TY - CONF
A1 - Abel, Andreas
T1 - Ambient and high-temperature mechanical properties of intermetallic Fe3Al alloys with complex borides
N2 - Due to the increasing scarcity of critical raw materials current high-temperature materials are sought to be replaced by alloys based on more abundant metals. One possibility within the class of intermetallics are iron aluminides, which combine sustainability and cost-efficiency with the prospect of mass savings. Iron aluminides show competitive specific strength up to 700 °C and excellent creep and wet corrosion resistance by small additions of Mo, Ti and B. Nevertheless, a Mo content of above 2 at.% which is needed for optimum corrosion resistance results in enhanced brittleness, especially at room temperature. This is why alloys with these Mo fractions were only mechanically tested under compressive loading so far. Still, testing of static and creep properties under tensile loading is required for reliable component design. Besides high standards for crack-free processing, data acquisition for tensile loads is especially complicated by environmental embrittling effects for iron aluminides. To cope with these challenges, the AiF research project “WAFEAL – Materials applications for iron aluminides” was initiated. The main goal is to collect standardised data on ambient and high-temperature tensile properties and creep properties. Samples with a nominal composition of Fe-26Al-4Mo-0.5Ti-1B [at.%] were manufactured via centrifugal casting in ceramic shell moulds followed by machining. Heat treatment for homogenisation and final polishing were carried out where appropriate. A summary of the achieved tensile and creep properties such as yield and tensile strength, maximum elongation, secondary creep rate and stress exponents will be given. Results will be also discussed regarding the influence of temperature, stress level and microstructure on the damage mechanisms. Furthermore, the effect of different alloy concentrations on the mechanical response at different temperatures will be outlined within a small experimental series.
T2 - MSE Congress 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Fe-Al alloys
KW - Intermetallics
KW - Iron aluminides
KW - Tensile data
KW - High temperature mechanical properties
KW - Creep data
KW - Fractography
PY - 2022
AN - OPUS4-55993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Kai
T1 - ToF-SIMS as a new tool for nano-scale investigation of ps-laser generated surface structures on Titanium substrates
N2 - The fabrication of laser-generated surface structures on titanium and titanium alloys has recently gained remarkable interests, being technologically relevant for applications in optics, medicine, fluid transport, tribology, and wetting of surfaces. The morphology of these structures, and so their chemistry, is influenced by the different laser processing parameters such as the laser fluence, wavelength, pulse repetition rate, the effective number of laser pulses per beam spot area, etc. A simple way to characterize laser-generated surface structures is by means of optical microscopy (OM) or white light interference microscopy (WLIM). The latter can address the surface topography, while having a lateral resolution limit of ~(lambda)/2 (lambda = illumination wavelength). To resolve morphologies with spatial periods significantly smaller than (lambda)/2, scanning electron microscopy (SEM) is often used, taking benefit of the reduced de Broglie wavelength associated to the electrons of several keV energy. However, all the above-mentioned techniques lack the necessary depth-resolution to reveal and quantify sub-surface material modifications of these laser-generated structures. Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) represents a promising surface analytical technique for studying laser-induced chemical surface alterations since the method combines a high surface sensitivity with the capability to perform a depth-profiling of the laser-affected surface zone. In this study we combine WLIM and high-resolution SEM with ToF-SIMS to fully characterize the evolution of various types of laser-generated micro- and nanostructures formed on Ti-6Al-4V alloys upon irradiation by near infrared ultrashort laser pulses (1030 nm, 925 fs) at different laser fluence levels, effective number of pulses, and at different pulse repetition rates (1 – 400 kHz). We show how this combined surface analytical approach allows to evaluate alterations in the surface chemistry and topography of the laser-generated surface structures depending on the laser processing parameters
T2 - ECASIA 2022
CY - Limerick, Ireland
DA - 29.05.2022
KW - Laser-induced periodic surface structures
KW - Time of Flight - Secondary ion mass spectrometry
KW - White light interferometric microscopy
KW - Titanium alloy
PY - 2022
AN - OPUS4-54992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Han, Ying
T1 - Aluminium High Temperature Fatigue
N2 - The studied aluminium alloy is EN AW-2618A (2618A). It is very widely used for exhaust gas turbo-charger compressor wheels. Due to long operating times, high cycle fatigue (HCF) and material aging under the influence of temperatures up to 230 °C is particularly relevant for the wheels. The wheels are typically milled from round wrought blanks. From such round blanks, different testpieces are extracted and a comprehensive series of HCF tests is conducted at room temperature. The tests investigate the materials fatigue performance in the T61 state for two load-ratios, namely R = -1 and R = 0.1. Additionally, two overaged material states are tested, accounting for the aging process the material undergoes during long operating times at high temperatures. The experimental results are evaluated and compared to each other.
Furthermore, the design process of notched specimens is presented. With the notched specimens, it is aimed to quantify the notch sensitivity of the material. Relating thereto, two potential model parameters for the fatigue lifetime model are introduced.
T2 - FVV Frühjahrstagung 2022
CY - Würzburg, Germany
DA - 31.03.2022
KW - High Cycle Fatigue
KW - Aluminium Alloy
KW - EN AW-2618A
PY - 2022
AN - OPUS4-54886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knigge, Xenia
A1 - Guo, Z.
A1 - Valsami-Jones, E.
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Influence of Sterilization on the Surface of Nanoparticles Studied with XPS / HAXPES in Comparison to SEM / EDS
N2 - Nanosafety is becoming increasingly important as nanomaterials are widely used in industrial processes and consumer products. For nanotoxicity measurements prior sterilization of the samples is necessary, but as structure activity relationships are made with properties of pristine particles, the question arises, if the sterilization process has an impact on the physico-chemical properties of nanoparticles and thus on the biological behavior.
This question will be addressed in this talk. For this purpose, results from SEM and EDS measurements are combined with those of a novel lab-based HAXPES spectrometer in order to obtain a more complete picture. At the end, an influence of sterilization will be evident, which indicates a restructuring of the nanoparticles owing to sterilization.
T2 - Microscopy & Microanalysis 2022
CY - Portland, USA
DA - 31.07.2022
KW - XPS
KW - HAXPES
KW - SEM
KW - EDS
KW - Nanoparticles
PY - 2022
DO - https://doi.org/10.1017/S1431927622004287
VL - 28
SP - 986
EP - 988
PB - Cambridge University Press
AN - OPUS4-55352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Han, Ying
T1 - High cycle fatigue behavior of alloy EN AW-2618A
N2 - The presentation shows the results of high cycle fatigue (HCF) tests from the aluminium alloy EN AW-2618A. This study investigates the mean stress influence in the T61 condition and the effect of overaging. For this purpose, axial HCF tests were carried out at room temperature and different stress ratios (R=-1, R=0.1) as well as with overaged conditions (T61+10h@230°C, T61+1000h@230°C). After completion of the tests, the fracture surfaces were examined to study crack initiation.
T2 - The 18th International Conference on Aluminium Alloys
CY - Toyama, Japan
DA - 04.09.2022
KW - High Cycle Fatigue
KW - Aluminium Alloy
KW - EN AW-2618A
PY - 2022
AN - OPUS4-55865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Skrotzki, Birgit
T1 - Brinell-Hardness (HBW 2.5/62.5) of Al-alloy EN AW-2618A after different aging times and temperatures
N2 - The dataset contains data from Brinell hardness measurements of Al-alloy EN AW-2618A after aging for different times and temperatures. Aging was either load free or with applied tensile load (creep).
KW - Aluminium alloy
KW - EN AW-2618A
KW - Brinell hardness
KW - Aging
KW - Creep
PY - 2022
UR - https://doi.org/10.5281/zenodo.6787085
UR - https://doi.org/10.5281/zenodo.10396823
DO - https://doi.org/10.5281/zenodo.6787084
PB - Zenodo
CY - Geneva
AN - OPUS4-55158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Han, Ying
A1 - Radners, J.
A1 - von Hartrott, P.
A1 - Skrotzki, Birgit
T1 - Aluminium high temperature fatigue
N2 - The studied aluminium alloy is EN AW-2618A (2618A). It is very widely used for exhaust gas turbo-charger compressor wheels. Due to long operating times, high cycle fatigue (HCF) and material aging under the influence of temperatures up to 230 °C is particularly relevant for the wheels. The wheels are typically milled from round wrought blanks. From such round blanks, different testpieces are extracted and a comprehensive series of HCF tests is conducted at room temperature. The tests investigate the materials fatigue performance in the T61 state for two load-ratios, namely R = -1 and R = 0.1. Additionally, two overaged material states are tested, accounting for the aging process the material undergoes during long operating times at high temperatures. The experimental results are evaluated and compared to each other.
Furthermore, the design process of notched specimens is presented. With the notched specimens, it is aimed to quantify the notch sensitivity of the material. Relating thereto, two potential model parameters for the fatigue lifetime model are introduced. Finally, the extended research data management in this project is highlighted and its advantages for sustainable use in material science and engineering applications are shown.
N2 - In diesem Projekt wird die Aluminiumlegierung EN AW-2618A (2618A) untersucht, welche sehr verbreitet in Verdichterrädern von Abgasturboladern zum Einsatz kommt. Hochzyklische Ermüdung und Werkstoffalterung bei Temperaturen von bis zu 230 °C ist bei Abgasturboladern aufgrund der langen Einsatzzeiten besonders relevant. Die Verdichterräder werden typischerweise aus geschmiedeten Rohlingen gefräst. Aus entsprechenden Rohlingen werden im Rahmen des Projekts eine Vielzahl von Proben mit unterschiedlichen Geometrien entnommen. Die Proben werden unter verschiedenen Prüfbedingungen in hochzyklischen Ermüdungsversuchen bei Raumtemperatur getestet. Zum einen wird das Ermüdungsverhalten des Werkstoffs im T61-Zustand für die zwei Belastungsverhältnisse R = -1 und R = 0,1 untersucht. Zum anderen werden zwei überalterte Materialzustände getestet. Damit soll dem Alterungsprozess Rechnung getragen werden, den das Material während langer Betriebszeiten bei hohen Temperaturen durchläuft. Die experimentellen Ergebnisse werden evaluiert und miteinander verglichen.
Darüber hinaus wird der Entwurfsprozess von gekerbten Probengeometrien dokumentiert. Die gekerbten Proben sollen Aufschluss über die Kerbempfindlichkeit des Werkstoffs geben. In diesem Zusammenhang werden zwei mögliche Modellparameter für das zu entwickelnde Lebensdauermodell vorgestellt. Abschließend wird das erweiterte Forschungsdatenmanagement des Projekts beleuchtet und seine Vorteile für die nachhaltige Nutzung in materialwissenschaftlichen und ingenieurtechnischen Anwendungen aufgezeigt.
T2 - FVV Frühjahrstagung 2022
CY - Würzburg, Germany
DA - 31.03.2022
KW - EN AW-2618A
KW - High cycle fatigue
KW - Aluminium alloy
PY - 2022
IS - FVV Publikationen Heft R602
SP - 617
EP - 634
PB - Forschungsvereinigung Verbrennungskraftmaschinen (FVV)
CY - Frankfurt am Main
AN - OPUS4-54622
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Habibimarkani, Heydar
T1 - Time-of-flight secondary ion mass spectrometry (ToF-SIMS) for in situ investigation on FeNi nanoparticles
N2 - The modern economy is dependent on catalysis, which is main efforts to create environmentally and energy-friendly technologies. The storage of excess electrical energy into chemical energy by splitting water into hydrogen and oxygen is a feasible solution to this energy demand. Due to their abundance on Earth and inherent stability in alkaline solution, transition-metal oxides have become one of several viable alternatives to noble-metal catalysts. Since NiFe oxide is one of the most active oxygen evolution reaction (OER) electrocatalysts for alkaline water electrolysis, it has been the subject of extensive research.
In this work, NiFe2O4 nanoparticles (NPs) of various sizes, specific stoichiometric and non-stoichiometric Fe:Ni surface ratios are synthesized. we will use a combination of ultra-high vacuum surface analysis techniques, such as time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS), to obtain the detailed characterization of the OER electrocatalysts top-surface layer, which is required to identify the rate-limiting step intermediates, and surface morphological changes at the electrolyte/catalyst.
T2 - SALSA Make&Measure 2022
CY - Berlin, Germany
DA - 15.09.2022
KW - ToF-SIMS
KW - FeNi nanoparticles
PY - 2022
AN - OPUS4-56157
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Liaison report from VAMAS with ISO/TC 202 Microbeam Analysis
N2 - The progress in the activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects/inter-laboratory comparisons. The recently started project FIB sample processing for TEM is presented. Next projects in the pipeline involving EBSD and TKD are shortly announced. The need of more promotion for the engagement of more experts from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed.
T2 - 29th Annual Meeting of ISO/TC 202 Microbeam Analysis
CY - Online meeting
DA - 28.11.2022
KW - VAMAS
KW - ISO/TC 202
KW - Microbeam Analysis
KW - EBSD
KW - Electron microscopy
KW - Thin films
PY - 2022
AN - OPUS4-56424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Verknüpfung von Datenrepositorien: Die Plattform MaterialDigital (PMD)
N2 - Vorstellung der Plattform MaterialDigital. Darstellung der Bedürfnisse und Herausforderungen in der Materialwissenschaft und Werkstofftechnik.
T2 - Vision Keramik
CY - Dresden, Germany
DA - 07.06.2022
KW - Digitalisierung
KW - Ontologie
KW - Standardisierung
PY - 2022
AN - OPUS4-54979
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Morphology Analysis of Graphene Oxide Flakes with SEM - Preparation of an Inter-Laboratory Comparison @VAMAS
N2 - Experience gained at BAM within the European project ISGScope on the accurate measureemnt of graphene oxide flakes by electron microscopy is presented. Particularly, factors such as the type of solvent, substrate temperature, but also proper, gentle measurement parameters and image analysis conditions towards automation are highlighted. The measurement procedures in develeopment are being prepared to launch an inter-laboratory comparison under VAMAS (TWA41) as preparatory guidance for future standardisation at ISO.
T2 - ISO/TC 229 Nanotechnologies Plenary Meeting - Graphene Standardisation
CY - Teddington, UK
DA - 14.11.2022
KW - Graphene oxide flakes
KW - SEM
KW - Morphology
KW - VAMAS
KW - Standardisation
KW - Sample preparation
KW - ISOGScope
PY - 2022
AN - OPUS4-56300
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, L. M.
A1 - Müller, J. T.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Schmidt, J.
A1 - Bekheet, M. F.
A1 - Gurlo, A.
A1 - Simon, U.
T1 - Hierarchically porous and mechanically stable monoliths from ordered mesoporous silica and their water filtration potential
N2 - Mechanically stable structures with interconnected hierarchical porosity combine the benefits of both small
and large pores, such as high surface area, pore volume, and good mass transport capabilities. Hence, lightweight micro-/meso-/macroporous monoliths are prepared from ordered mesoporous silica COK-12 by means of spark plasma sintering (SPS, S-sintering) and compared to conventionally (C-) sintered monoliths. A multi-scale model is developed to fit the small angle X-ray scattering data and obtain information on the hexagonal lattice parameters, pore sizes from the macro to the micro range, as well as the dimensions of the silica population. For both sintering techniques, the overall mesoporosity, hexagonal pore ordering, and amorphous character are preserved. The monoliths' porosity (77–49%), mesopore size (6.2–5.2 nm), pore volume (0.50–0.22 g cm-3
), and specific surface area (451–180 m2 g-1) decrease with increasing processing temperature and pressure. While the difference in porosity is enhanced, the
structural parameters between the C-and S-sintered monoliths are largely converging at 900 C, except for the mesopore size and lattice parameter, whose dimensions are more extensively preserved in the
S-sintered monoliths, however, coming along with larger deviations from the theoretical lattice. Their higher mechanical properties (biaxial strength up to 49 MPa, 724 MPa HV 9.807 N) at comparable porosities and ability to withstand ultrasonic treatment and dead-end filtration up to 7 bar allow S-sintered monoliths to reach a high permeance (2634 L m-2 h-1 bar-1), permeability (1.25 x 10^-14 m2), and ability to reduce the chemical oxygen demand by 90% during filtration of a surfactant-stabilized oil in water emulsion, while indicating reasonable resistance towards fouling.
KW - SAXS
KW - Hierarchically porous
KW - Silica
KW - Water filtration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555928
DO - https://doi.org/10.1039/D2NA00368F
SN - 2516-0230
SP - 1
EP - 17
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-55592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Pauw, Brian Richard
T1 - How to run a (lab) SAXS instrument efficiently
N2 - Here I talk about our holistic approach to X-ray scattering, and what improvements we made to our methodology to make measuring with us a very streamlined process.
KW - Laboratory management
KW - MOUSE
KW - X-ray scattering
KW - Instrument utilization
KW - Research efficiency
KW - Automation
KW - Metadata collection
KW - Laboratory automation
PY - 2022
UR - https://www.youtube.com/watch?v=ncadUQ43Uwc
DO - https://doi.org/10.26272/opus4-55761
PB - YouTube, LLC
CY - San Bruno, CA, USA
AN - OPUS4-55761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruna, F. G.
A1 - Prokop, M.
A1 - Bystron, T.
A1 - Loukrakpam, R.
A1 - Melke, J.
A1 - Lobo, C. M. S.
A1 - Fink, M.
A1 - Zhu, M.
A1 - Voloshina, E.
A1 - Kutter, M.
A1 - Hoffmann, H.
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, B.
A1 - Bouzek, K.
A1 - Paulus, B.
A1 - Roth, C.
T1 - Following adsorbed intermediates on a platinum gas diffusion electrode in H3PO3‑containing electrolytes using in situ X‑ray absorption spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalyst with H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - Δμ XANES
KW - H3PO3
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - ACS
CY - Washington, DC
AN - OPUS4-55815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lin, R.
A1 - Li, X.
A1 - Krajnc, A.
A1 - Li, Z.
A1 - Li, M.
A1 - Wang, W.
A1 - Zhuang, L.
A1 - Smart, S.
A1 - Zhu, Z.
A1 - Appadoo, D.
A1 - Harmer, J. R.
A1 - Wang, Z.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Beyer, S.
A1 - Wang, L.
A1 - Mali, G.
A1 - Bennett, T. D.
A1 - Chen, V.
A1 - Hou, J.
T1 - Mechanochemically Synthesised Flexible Electrodes Based on Bimetallic Metal–Organic Framework Glasses for the Oxygen Evolution Reaction
N2 - The melting behaviour of metal–organic frameworks (MOFs) has aroused significant research interest in the areas of materials science, condensed matter physics and chemical engineering. This work first introduces a novel method to fabricate a bimetallic MOF glass, through meltquenching of the cobalt-based zeolitic imidazolate Framework (ZIF) [ZIF-62(Co)] with an adsorbed ferric coordination complex. The high-temperature chemically reactive ZIF-62-(Co) liquid facilitates the formation of coordinative bonds between Fe and imidazolate ligands, incorporating Fe nodes into the framework after quenching. The resultant Co–Fe bimetallic MOF glass therefore shows a significantly enhanced oxygen evolution reaction performance. The novel bimetallic MOF glass, when combined with the facile and scalable mechanochemical synthesis technique for both discrete powders and surface coatings on flexible substrates, enables significant opportunities for catalytic device Assembly
KW - Electrodes
KW - MOF
KW - OER
KW - XANES
KW - XAS
KW - Bimetallic frameworks
PY - 2022
DO - https://doi.org/10.1002/anie.202112880
VL - 61
IS - 4
SP - e202112880
PB - Wiley
AN - OPUS4-54018
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Abrudan, R.
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Schneider, M.
A1 - Laplanche, G.
A1 - Yusenko, Kirill
T1 - Inner relaxations in equiatomic single-phase high-entropy Cantoralloy
N2 - The superior properties of high-entropy multi-functional materials are strongly connected with their atomic heterogeneity through many different local atomic interactions. The detailed element-specific studies on a local scale can provide insight into the primary arrangements of atoms in multicomponent systems and benefit to unravel the role of individual components in certain macroscopic properties of complex compounds. Herein, multi-edge X-ray absorption spectroscopy combined with reverse Monte Carlo simulations was used to explore a homogeneity of the local crystallographic ordering and specific structure relaxations of each constituent in the equiatomic single-phase facecentered cubic CrMnFeCoNi high-entropy alloy at room temperature. Within the considered fitting approach, all five elements of the alloy were found to be distributed at the nodes of the fcc lattice without any signatures of the additional phases at the atomic scale and exhibit very close statistically averaged interatomic distances (2.54 – 2.55 Å) with their nearest-neighbors. Enlarged structural displacements were found solely for Cr atoms. The macroscopic magnetic properties probed by conventional magnetometry demonstrate no opening of the hysteresis loops at 5 K and illustrate a complex character of the long-range magnetic order after field-assisted cooling in ± 5 T. The observed magnetic behavior is assigned to effects related to structural relaxations of Cr. Besides, the advantages and limitations of the reverse Monte Carlo approach to studies of multicomponent systems like high-entropy alloys are highlighted.
KW - Magnetism
KW - High-entropy alloys
KW - Reverse Monte Carlo (RMC)
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS)
KW - X-ray absorption near edge structure (XANES)
PY - 2022
DO - https://doi.org/10.1016/j.jallcom.2022.165999
SN - 0925-8388
VL - 920
SP - 1
EP - 31
PB - Elsevier
AN - OPUS4-55457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time resolved in situ monitoring of mechanochemical transformations by X-ray absorption spectroscopy (XAS)
N2 - Mechanochemical reactions promise a new direction for environmentally benign preparation of materials, and has been dubbed by IUPAC as one of the 10 chemical innovations that will change our world. Despite this significant promise, very little is known about the mechanisms that drive mechanochemical transformations, posing significant barriers to realizing their full potential. To this end, there is growing need to follow mechanochemical reactions in situ and in real time. We here describe advances in the development and application of XAS methods to monitor material synthesis in real time under mechanochemical conditions. We demonstrate the generality of our approaches by describing mechanochemical syntheses of materials by both vibratory ball milling and by Resonant Acoustic Mixing (RAM), where a time resolution of 1 second is for a whole XAS spectrum was achieved. Moreover, we describe how spectroscopic methods can be coupled to diffraction-based approaches, thereby providing new dimensions in understanding mechanochemical synthesis.
T2 - Advances X ray Analytics Seminar at TU Berlin
CY - Berlin, Germany
DA - 14.06.2022
KW - XAS
KW - Mechanochemistry
KW - Time resolved
KW - In situ
PY - 2022
AN - OPUS4-56259
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Flatken, M. A.
A1 - Radicchi, E.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Härk, E.
A1 - Pascual, J.
A1 - Mathies, F.
A1 - Shargaieva, O.
A1 - Prause, A.
A1 - Dallmann, A.
A1 - De Angelis, F.
A1 - Hoell, A.
A1 - Abate, A.
T1 - Role of the Alkali Metal Cation in the Early Stages of Crystallization of Halide Perovskites
N2 - ABX3 metal halide perovskites revolutionized the research and development of new optoelectronics, including solar cells and light-emitting diodes. Processing polycrystalline thin films from precursor solutions is one of the core advantages of these materials since it enables versatile and cost-effective manufacturing. The perovskite film morphology, that is, continuous substrate coverage and low surface roughness, is of paramount importance for highly efficient solar cells and optoelectronic devices in general. Controlling the chemistry of precursor solutions is one of the most effective strategies to manage the perovskite film morphology. Herein, we show the fundamental influence of the A-site cation composition on the perovskite precursor arrangement and the consequent film formation. Extended X-ray absorption fine structure spectroscopy and small-angle X-ray scattering give unprecedented insights into the complex structural chemistry of the perovskite precursors and, in particular, their repulsive interactions as a crucial parameter for colloidal stability. Combining these techniques with in situ grazing incidence wide-angle X-ray scattering during thin-film formation allows us to identify the mechanism for using alkali metals as a decisive criterion to control the colloidal stability of the perovskite precursor and thus the thin-film morphology. We illustrate the fundamental principle behind the systematic use of alkali metals regardless of whether they are incorporated in the lattice or not. Hence, this work provides tools to selectively control the morphology and crystal growth in present and future systems
KW - MAPbI3 perovskites
KW - Halide Perovskites
KW - X-ray absorption spectroscopy
PY - 2022
DO - https://doi.org/10.1021/acs.chemmater.1c03563
SN - 0897-4756
VL - 34
IS - 3
SP - 1121
EP - 1131
PB - American Chemical Society
AN - OPUS4-54713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tiebe, Carlo
T1 - Materialuntersuchungen zur Schadensanalyse an einem explodierten Umlaufkühler
N2 - Ein Umlaufkühler ist im Betrieb explodiert. Splitter des zerborstenen Gehäuses aus Kunststoff wurden mit dem Kühlwasser in die Umgebung geschleudert, am Betriebsort entstand Personenschaden. Bei Funktionsprüfungen am beschädigten Gerät traten unerwartet - aber reproduzierbar - Knalleffekte bei Berührung der Außenoberfläche der Kupfer-Kühlschlange auf. Ein möglicher Mechanismus konnte im Labor durch Synthese von Kupferazid auf Kupferproben und Auslösung vergleichbarer Knalleffekte nachgestellt werden. Damit ist die Plausibilität des beschriebenen Schadensereignisses mit diesem oder einem ähnlich reagierenden Stoff belegt. Ein eindeutiger Nachweis darüber, dass bei dem aufgetretenen Schadensfall dieselbe chemische Reaktion stattgefunden hat, war nicht möglich, da die Belag-Überreste aus dem explodierten Kühlgerät für eine Analyse nicht mehr in ausreichender Menge verfügbar gewesen sind.
T2 - BG RCI Präventionstagung, Teil 11 - Inkompatible Systeme – Wenn Chemikalien und Werkstoffe heftig reagieren
CY - Online meeting
DA - 19.01.2022
KW - Explosion
KW - Gutachten
KW - Kupferazid
KW - Materialuntersuchung
KW - Schadensanalyse
KW - Umlaufkühler
PY - 2022
AN - OPUS4-56686
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tiebe, Carlo
A1 - Zunkel, Astrid
A1 - Klein, Ulrich
A1 - Schlischka, Jörg
A1 - Klinger, Christian
T1 - Materialuntersuchungen an einem explodierten Umlaufkühler
N2 - Ein Umlaufkühler ist im Betrieb explodiert. Splitter des zerborstenen Gehäuses aus Kunststoff wurden mit dem Kühlwasser in die Umgebung geschleudert, am Betriebsort entstand Personenschaden. Bei Funktionsprüfungen am beschädigten Gerät traten unerwartet - aber reproduzierbar - Knalleffekte bei Berührung der Außenoberfläche der Kupfer-Kühlschlange auf. Ein möglicher Mechanismus konnte im Labor durch Synthese von Kupferazid auf Kupferproben und Auslösung vergleichbarer Knalleffekte nachgestellt werden. Damit ist die Plausibilität des beschriebenen Schadensereignisses mit diesem oder einem ähnlich reagierenden Stoff belegt. Ein eindeutiger Nachweis darüber, dass bei dem aufgetretenen Schadensfall dieselbe chemische Reaktion stattgefunden hat, war nicht möglich, da die Belag-Überreste aus dem explodierten Kühlgerät für eine Analyse nicht mehr in ausreichender Menge verfügbar gewesen sind.
KW - Kupferazid
KW - Umlaufkühler
KW - Explosion
KW - Gutachten
KW - Schadensanalyse
KW - Materialuntersuchung
PY - 2022
SN - 2191-0073
VL - 12
IS - 7/8
SP - 15
EP - 21
PB - VDI Fachmedien
CY - Düsseldorf
AN - OPUS4-55570
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by glow-discharge optical emission spectroscopy
N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs.
T2 - Adlershofer Forschungsforum 2022
CY - Berlin, Germany
DA - 11.11.2022
KW - Lithium Ion Batteries
KW - GD-OES
KW - FIB
KW - SEM
KW - EDX
PY - 2022
AN - OPUS4-56246
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by GD-OES
N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs.
T2 - Empa Group Meeting
CY - Dübendorf, Switzerland
DA - 22.11.2022
KW - Lithium Ion Batteries
KW - GD-OES
KW - FIB
KW - SEM
KW - EDX
PY - 2022
AN - OPUS4-56584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time resolved in situ monitoring of mechanochemical transformations by X-ray absorption spectroscopy (XAS)
N2 - Mechanochemical reactions promise a new direction for environmentally benign preparation of materials, and has been dubbed by IUPAC as one of the 10 chemical innovations that will change our world. Despite this significant promise, very little is known about the mechanisms that drive mechanochemical transformations, posing significant barriers to realizing their full potential. To this end, there is growing need to follow mechanochemical reactions in situ and in real time. We here describe advances in the development and application of XAS methods to monitor material synthesis in real time under mechanochemical conditions. We demonstrate the generality of our approaches by describing mechanochemical syntheses of materials by both vibratory ball milling and by Resonant Acoustic Mixing (RAM), where a time resolution of 1 second is for a whole XAS spectrum was achieved. Moreover, we describe how spectroscopic methods can be coupled to diffraction-based approaches, thereby providing new dimensions in understanding mechanochemical synthesis.
T2 - European Conference on X-ray Spectrometry 2022
CY - Bruges, Belgium
DA - 27.06.2022
KW - XAS
KW - Mechanochemictry
KW - Time resolved
KW - In situ
PY - 2022
AN - OPUS4-56258
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sonntag, Nadja
T1 - Dwell-Fatigue and Cyclic Softening of Grade P92 Steel under LCF and TMF Conditions
N2 - Tempered martensite-ferritic steels, such as the grade P92 steel studied in this contribution, exhibit pronounced macroscopic cyclic softening under isothermal low-cycle fatigue (LCF) and non-isothermal thermomechanical fatigue (TMF) conditions, which is considered to be the predominant degradation mechanism in high-temperature fatigue in this and other material groups. However, such softening processes are highly complex since microscopic (e.g., recovery) and macroscopic (e.g., crack initiation and growth), as well as global and local effects superimpose, especially under creep-fatigue conditions. In this contribution, we discuss the cyclic deformation and softening behavior of P92 in strain-controlled LCF, in-phase (IP) TMF, and out-of-phase (OP) TMF tests with and without dwell times in the temperature range from 300 °C to 620°C. EBSD-based dislocation analysis on various fatigued material states confirms the continuous redistribution and annihilation of geometrically necessary dislocations in all studied states, which can be quantitatively correlated with macroscopic softening despite different damage mechanisms for different test types. Deviations from this correlation are observed for OP TMF and LCF with dwell times, i.e., for conditions where optical microscopy reveals pronounced crack-oxidation interactions at the specimen surfaces.
T2 - LCF9 - Ninth International Conference on Low Cycle Fatigue
CY - Berlin, Germany
DA - 21.06.2022
KW - LCF
KW - TMF
KW - EBSD
PY - 2022
DO - https://doi.org/10.48447/LCF9-2022-111
AN - OPUS4-55128
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Fedelich, Bernard
ED - Cailletaud, G.
ED - Cormier, J.
ED - Eggeler, G.
ED - Maurel, V.
ED - Nazé, L.
T1 - Crystal orientation and elastic properties
N2 - The elastic constants are the most basic mechanical properties of a material and are needed for any structural analysis of a component. For example, they have a major influence on the eigenfrequencies of vibrating parts. Single crystals of Ni-base superalloys are strongly anisotropic, which means that the observed properties are orientation dependent. Tensor algebra is then required to mathematically formulate the elastic properties and their relations to the crystal orientation. Hence, this chapter first summarizes some basic definitions and calculation rules for Rotation matrices, including the definition of the Euler angles, which are most commonly used to define the relative orientations of the crystal and the component. Parts of this chapter closely follow the lines of the excellent exposition of the topic by Olschewski.
KW - Nickel-base superalloys
KW - Elasticity
PY - 2022
SN - 978-0-12-819357-0
SP - 41
EP - 67
PB - Elsevier Inc.
AN - OPUS4-53435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Drexler, A
A1 - Konert, Florian
A1 - Sobol, Oded
A1 - Rhode, Michael
A1 - Domitner, J
A1 - Sommitsch, C
A1 - Böllinghaus, Thomas
T1 - Enhanced gaseous hydrogen solubility in ferritic and martensitic steels at low temperatures
N2 - Metals that are exposed to high pressure hydrogen gas may undergo detrimental failure by embrittlement. Understanding the mechanisms and driving forces of hydrogen absorption on the surface of metals is crucial for avoiding hydrogen embrittlement. In this study, the effect of stress-enhanced gaseous hydrogen uptake in bulk metals is investigated in detail. For that purpose, a generalized form of Sievert's law is derived from thermodynamic potentials considering the effect of microstructural trapping sites and multiaxial stresses. This new equation is parametrized and verified using experimental data for carbon steels, which were charged under gaseous hydrogen atmosphere at pressures up to 1000 bar. The role of microstructural trapping sites on the parameter identification is critically discussed.
KW - Hydrogen
KW - Thermodynamic modelling
KW - Pressure-dependent solubility
KW - Steel
KW - Trapping
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559307
DO - https://doi.org/10.1016/j.ijhydene.2022.09.109
SN - 0360-3199
VL - 47
IS - 93
SP - 39639
EP - 39653
PB - Elsevier Ltd.
AN - OPUS4-55930
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocano, Patricia
A1 - Fries, S. G.
A1 - Lopez-Galilea, I.
A1 - Darvishi Kamachali, Reza
A1 - Roik, J.
A1 - Agudo Jácome, Leonardo
T1 - The AlMo0.5NbTa0.5TiZr refractory high entropy superalloy: Experimental findings and comparison with calculations using the CALPHAD method
N2 - Detailed microstructural characterization of the AlMo0.5NbTa0.5TiZr refractory high entropy superalloy in the as-cast state is reported for first time and compared with the state annealed at 1400 oC for 24 h. The former shows a dendritic structure, with a mixture of A2/B2 phases < 20 nm in both the dendritic and interdendritic regions. A mostly amorphous phase, rich in Al and Zr, is found within the interdendritic region. The annealed state reproduced the combination of A2/B2/Al-Zr-rich phases reported previously. Calculations from two relevant ThermoCalc databases were compared with the experimental results. Equilibrium calculations were compared with results for the annealed alloy, whereas solidification paths calculated using Scheil-Gulliver model were used for comparison with the as-cast alloy. A previously hypothesized spinodal decomposition during cooling as the mechanism responsible for the patterned A2/B2 microstructure is confirmed via the CALPHAD calculations, pointing to its use as an efficient design tool for such alloys. Finally, the comparison between the experimental and computational findings allowed better understanding the solidification path and equilibrium stability of this alloy, giving a base to make better decisions on the field of new refractory superalloy design.
KW - CALPHAD database analysis
KW - Refractory superalloys
KW - Chemically complex alloy
KW - Characterization
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545906
DO - https://doi.org/10.1016/j.matdes.2022.110593
SN - 1873-4197
VL - 217
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xing, H.
A1 - Jing, H.
A1 - Dong, X.
A1 - Wang, Lei
A1 - Han, Y.
A1 - Hu, R.
T1 - Cellular growth during rapid directional solidification: Insights from quantitative phase field simulations
N2 - In this paper, columnar cellular growth with kinetic effects including kinetic undercooling and solute trapping in rapid directional solidification of alloys was investigated by using a recent quantitative phase-field model for rapid solidification. Morphological transition and primary spacing selection with and without kinetic effects were numerically investigated. Numerical results show that doublon structure is an intermediate state in the primary spacing adjustment of cellular arrays. It was found that the inclusions of kinetic effects result in the increase of the solute in the solid phase and the solute enrichment in the interdendritic liquid channel. Moreover, predicted results indicate that the growth directions of the cellular arrays in rapid directional solidification with and without kinetic effects are independent of the Péclet number. Therefore, the kinetic effects play important roles in numerical simulations of the growth pattern selection and solute distribution during rapid solidification. Neglecting them will result in the inaccurately predicted results.
KW - Rapid solidification
KW - Phase-field model
PY - 2022
DO - https://doi.org/10.1016/j.mtcomm.2022.103170
VL - 30
SP - 103170
PB - Elsevier Ltd.
AN - OPUS4-54571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ganesh, R.
A1 - Gesell, Stephan
A1 - Fedelich, Bernard
A1 - Kuna, Meinhard
A1 - Kiefer, B.
T1 - Procrackplast: Eine Software zur Simulation des 3D-Risswachstums unter großen plastischen Deformationen
T1 - Procrackplast: A software for simulating 3D crack growth under large plastic deformation
N2 - The finite element software ProCrackPlast is developed for the automated simulation of fatigue crack growth in arbitrarily loaded three-dimensional components with large scale plastic deformations, in particular under cyclic thermomechanical (TMF) loading.
ProCrackPlast is developed by extending the software Procrack, created at TU Freiberg for linear-elastic crack growth simulations. The pre-processing, FEM analysis, and the post-processing in ProCrackPlast are done by the commercial software ABAQUS. ProCrackPlast resorts to a crack growth procedure which adaptively updates the crack in finite increments based on the fracture-mechanical parameter, cyclic crack tip opening displacement ΔCTOD . Features of this software along with two application examples of fatigue crack growth in a typical cast steel, Ni-Resist, are presented in this paper to show its capability and performance.
N2 - Es wird die Finite-Element-Software ProCrackPlast vorgestellt, die eine automatische Simulation der Ermüdungsrissausbreitung in beliebig belasteten dreidimensionalen Bauteilen mit größeren plastisch verformten Bereichen ermöglicht, insbesondere bei thermomechanischer Wechselbelastung (TMF). ProCrackPlast entstand durch Erweiterung des Programs ProCrack, das an der TU Freiberg für linear-elastische inkrementelle Rissfortschrittsanalysen entwickelt wurde. Das Pre-Processing, die FEM Analyse und das Post-Processing werden mit Hilfe der kommerziellen FE-Software ABAQUS durchgeführt.
ProCrackPlast beruht auf einem Algorithmus, mit dem der Rissfortschritt adaptiv in endlichen Inkrementen unter Verwendung des bruchmechanischen Parameters der zyklischen Rissöffnungsverschiebung ΔCTOD gesteuert wird. Die Funktionseigenschaften dieser Software werden anhand von zwei Anwendungsbeispielen zum Ermüdungsrisswachstum für einen typischen Stahlguss, Ni-Resist, exemplarisch dargestellt, um die Möglichkeiten und Leistungsfähigkeit von ProCrackPlast zu demonstrieren.
T2 - 54. Tagung des Arbeitskreises "Bruchmechanik und Bauteilsicherheit"
CY - Online meeting
DA - 22.02.2021
KW - Automated finite element analysis
KW - Automatische Finite Element Simulation
KW - Thermomechanical fatigue
KW - Crack growth
KW - Thermomechanische Ermüdung
KW - Rissausbreitung
PY - 2022
SP - 205
EP - 214
PB - Deutscher Verband für Materialforschung und -prüfung e.V.
AN - OPUS4-54435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ruffini, A.
A1 - Le Bouar, Y.
A1 - Finel, A.
A1 - Epishin, A. I.
A1 - Fedelich, Bernard
A1 - Feldmann, Titus
A1 - Viguier, B.
A1 - Poquillon, D.
T1 - Dislocations interacting with a pore in an elastically anisotropic single crystal nickel-base superalloy during hot isostatic pressing
N2 - The formation of pores in CMSX-4 nickel based superalloys is detrimental to the service life of the material. A way to avoid the problem is to treat the superalloys under Hot Isostatic Pressing (HIP), which enables a large volume fraction of pores to be annihilated. This paper aims to understand the contribution of plastic activity related to the gliding of dislocations on the pore annihilation. Simulations based on a phase-field model of dislocation are performed and make it possible to consider the strong anisotropy of the CMSX-4 under HIP conditions in conjunction to the strong elastic heterogeneity introduced by the pore. For pores with a radius of few micrometers, it is shown that edge parts of dislocation lines that present an extra half atomic plane oriented towards the pore are stacked above and under it in the direction which is perpendicular to their slip-planes, causing an increase of the number of dislocation along the four octahedral directions of the FCC single crystal which intersect the pore center. Results are streamlined within the isotropic elastic theory of dislocations. Effects of elastic anisotropy and dislocation reactions are also investigated in order to specify what would be the dislocation configuration around a pore in CMSX-4 under HIP conditions. Notably, the elastic anisotropy is shown to significantly modify the arrangement of dislocations close to the pore equator. Simulations also allow for the characterization of pore/dislocation interactions when dislocations are involved in Low Angle Boundaries as experimentally observed.
KW - HIP
KW - Superalloys
KW - Dislocation
KW - Pore
KW - Phase-field
PY - 2022
DO - https://doi.org/10.1016/j.commatsci.2021.111118
SN - 0927-0256
VL - 204
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54220
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
T1 - Melting upon Coalescence of Solid Nanoparticles
N2 - The large surface-to-volume ratio of nanoparticles is understood to be the source of many interesting phenomena. The melting temperature of nanoparticles is shown to dramatically reduce compared to bulk material. Yet, at temperatures below this reduced melting point, a liquid-like atomic arrangement on the surface of nanoparticles is still anticipated to influence its properties. To understand such surface effects, here, we study the coalescence of Au nanoparticles of various sizes using molecular dynamics simulations. Analysis of the potential energy and Lindemann index distribution across the nanoparticles reveals that high-energy, high-mobility surface atoms can enable the coalescence of nanoparticles at temperatures much lower than their corresponding melting point. The smaller the nanoparticles, the larger the difference between their melting and coalescence temperatures. For small enough particles and/or elevated enough temperatures, we found that the coalescence leads to a melting transition of the two nominally solid nanoparticles, here discussed in relation to the heat released due to the surface reduction upon the coalescence and the size dependence of latent heat. Such discontinuous melting transitions can lead to abrupt changes in the properties of nanoparticles, important for their applications at intermediate temperatures.
KW - Nanoparticles
KW - Molecular Dynamics
KW - Surface-induced Melting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552183
DO - https://doi.org/10.3390/solids3020025
VL - 3
IS - 2
SP - 361
EP - 373
PB - MDPI
AN - OPUS4-55218
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mosquera Feijoo, Maria
A1 - Oder, Gabriele
A1 - Saliwan Neumann, Romeo
A1 - Buchheim, Michaela
A1 - Kranzmann, Axel
A1 - Olbricht, Jürgen
T1 - Impact of Sample Geometry and Surface Finish on VM12‑SHC Ferritic–Martensitic Steel Under Cyclic Steam Atmosphere Operating Conditions
N2 - The steam side oxidation of ferritic–martensitic VM12-SHC steel was investigated under thermo-cyclic conditions in water steam at 620/320 °C and 30 bar with a focus on assessing the influence of pre-oxidation time, specimen geometry and surface finish. The specimens were pre-oxidized under isothermal conditions in water steam at 620 °C and 30 bar for 500 h or 1500 h. After pre-oxidation treatment, all specimens were subjected up to 258 thermal cycles. Three different geometries—rectangular coupons, U-shaped ring segments and ring samples—were investigated to evaluate the influence of open/closed shape, and flat/curved surface on corrosion rate. At the same time, two types of surface finish were considered: “as received” and “ground.” The formation of a protective scale by pre-oxidation was investigated. EBSD and ESMA analyses revealed that the Cr-content of the alloy appeared to be insufficient for obtaining a protective oxide scale under studied conditions, at the same time the anayses confirmed that initial oxidation depends on presence of minor alloying elements as Si and Mn, strong oxide formers which can alter the kinetics and morphology of the corrosion reaction. Moreover, rectangular coupons with small wall thickness and flat surface exhibited the highest corrosion rate, while “ground” curved samples showed only local oxidation. This indicates that for same pre-oxidation time, oxidation kinetics is controlled by curvature.
KW - Cyclic steam oxidation
KW - 12%Cr steel
KW - Specimen geometry
KW - Surface treatments
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551808
DO - https://doi.org/10.1007/s11085-022-10114-6
SN - 0030-770X
SP - 1
EP - 18
PB - Springer
AN - OPUS4-55180
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhou, X.
A1 - Wei, Y.
A1 - Kühbach, M.
A1 - Zhao, H.
A1 - Vogel, F.
A1 - Darvishi Kamachali, Reza
A1 - Thompson, G. B.
A1 - Raabe, D.
A1 - Gault, B.
T1 - Revealing in-plane grain boundary composition features through machine learning from atom probe tomography data
N2 - Grain boundaries (GBs) are planar lattice defects that govern the properties of many types of polycrystalline materials. Hence, their structures have been investigated in great detail. However, much less is known about their chemical features, owing to the experimental difficulties to probe these features at the atomic length scale inside bulk material specimens. Atom probe tomography (APT) is a tool capable of accomplishing this task, with an ability to quantify chemical characteristics at near-atomic scale. Using APT data sets, we present here a machine-learning-based approach for the automated quantification of chemical features of GBs. We trained a convolutional neural network (CNN) using twenty thousand synthesized images of grain interiors, GBs, or triple junctions. Such a trained CNN automatically detects the locations of GBs from APT data. Those GBs are then subjected to compositional mapping and analysis, including revealing their in-plane chemical decoration patterns. We applied this approach to experimentally obtained APT data sets pertaining to three case studies, namely, Ni-P, Pt-Au, and Al-Zn-Mg-Cu alloys. In the first case, we extracted GB specific segregation features as a function of misorientation and coincidence site lattice character. Secondly, we revealed interfacial excesses and in-plane chemical features that could not have been found by standard compositional analyses. Lastly, we tracked the temporal evolution of chemical decoration from early-stage solute GB segregation in the dilute limit to interfacial phase separation, characterized by the evolution of complex composition patterns. This machine-learning-based approach provides quantitative, unbiased, and automated access to GB chemical analyses, serving as an enabling tool for new discoveries related to interface thermodynamics, kinetics, and the associated chemistry-structure-property relations.
KW - Machine learning
KW - Digitalization
KW - Alloy microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543049
DO - https://doi.org/10.1016/j.actamat.2022.117633
SN - 1359-6454
VL - 226
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feldmann, Titus
A1 - Fedelich, Bernard
A1 - Epishin, A.
T1 - Simulation of Hot Isostatic Pressing in a Single-Crystal Ni Base Superalloy with the Theory of Continuously Distributed Dislocations Combined with Vacancy Diffusion
N2 - Single-crystal components made of nickel base superalloys contain pores after casting and homogenization heat treatment. Hot isostatic pressing (HIP), which is carried above the γ' -solvus temperature of the alloy, is industrially applied to reduce porosity. A modeling of HIP based on continuously distributed dislocations is developed in a 2D setting. Glide and climb of straight-edge dislocations, as well as vacancy diffusion, are the deformation mechanisms taken into account.
Thereby, dislocation glide is controlled by dragging a cloud of large atoms, and climb is controlled by vacancy diffusion. Relying on previous investigations of the creep behavior at HIP temperatures, it is assumed that new dislocations are nucleated at low-angle boundaries (LAB) and move through subgrains until they either reach the opposite LABs or react with other dislocations and annihilate.
Vacancies are created at the pore surface and diffuse through the alloy until they are either consumed by climbing dislocations or disappear at the LABs. The field equations are solved by finite elements. It is shown that pore shrinking is mostly controlled by vacancy diffusion as the shear stresses at the LABs are too low to
nucleate a sufficient amount of dislocations.
KW - Nickel-base superalloys
KW - HIP
KW - Dislocation
KW - Creep
KW - Model
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542309
DO - https://doi.org/10.1002/adem.202101341
VL - 2022
PB - Wiley
AN - OPUS4-54230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
A1 - Breidung, Marc
A1 - Wossidlo, Peter
A1 - Wahl, Ken
A1 - Gerwien, Peter
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Küppers, M.
ED - Zimmermann, Martina
T1 - Gezielte Werkstoffprüfung zur fail-safe-Bauteilauslegung am Beispiel eines Achsschenkels
N2 - Bei der Auslegung von Achsschenkeln für Nutzfahrzeuge wird für den Überlastfall ein fail-safe-Kriterium (kontrolliertes Versagen) als Basisphilosophie angesetzt. Gefordert wird, dass sich der Achsschenkel auch unter Akzeptanz begrenzten Risswachstums hinreichend elastisch-plastisch verformen kann, ohne dass es zum Bruch kommt. Der Fahrer soll anschließend anhand der bleibenden Verformungen bemerken können, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Eine Voraussetzung für dieses Bauteilverhalten ist eine hinreichende Bruchzähigkeit des Werkstoffs. Diese, wie auch die Rissspitzenbeanspruchung, müssen ermittelt werden, um den bruchmechanischen Sicherheitsnachweis führen zu können. Zur Ermittlung der mechanisch-technologischen und bruchmechanischen Werkstoffeigenschaften wurde ein Prüfkonzept entwickelt, bei dem die Proben an der potenziell kritischen Stelle direkt aus den geschmiedeten Achsschenkeln entnommen werden. Die experimentelle Werkstoffcharakterisierung bildet dann die Beanspruchungsbedingungen beim Überlastereignis ab. Im Rahmen der Produktion stehen jedoch nur Kerbschlagarbeitswerte zur Verfügung und aufwändige bruchmechanische Versuche sollen vermieden werden. Deshalb wurde eine Korrelation zur Abschätzung der vorhandenen Bruchzähigkeit aus der Kerbschlagarbeit herangezogen. Es ergibt sich eine Ergebnismatrix, die die Einflussgrößen Versagenswahrscheinlichkeit, Temperatur und Bruchzähigkeit verknüpft. Abschließend wird ein erster Vergleich der abgeschätzten mit den experimentell ermittelten Bruchzähigkeitswerten gezogen. Dieser weist aus, dass die abgeschätzten Werte geringfügig konservativ sind.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Kerbschlagarbeit
KW - Achsschenkel
KW - Fail-safe
KW - Bruchmechanische Auslegung
KW - Korrelation
PY - 2022
SP - 1
EP - 6
PB - DGM - Deutsche Gesellschaft für Materialkunde e.V.
CY - Sankt Augustin
AN - OPUS4-56152
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
ED - Zimmermann, M.
T1 - Zur Frage der Verwendung von Untermaßprobenergebnissen des Kerbschlagbiegeversuchs - Eine ernüchternde Bilanz
N2 - Der Kerbschlagbiegeversuch ist seit der ersten Hälfte des letzten Jahrhunderts standardisiert und seit langem als Prüfverfahren international genormt. Weltweit sind zu garantierende Werte der Kerbschlagenergie (KV) und Übergangstemperaturen (TÜ) in Produktnormen und Regelwerken festgelegt. Unter bestimmten Bedingungen besteht dabei die Option, statt Normalproben Untermaßproben zu prüfen. Im Rahmen einer Untersuchung der BAM wurde der aktuelle Status von Prüf- und Produktnormen sowie Regelwerken zur Bewertung der Bauteilintegrität hinsichtlich ihres Umgangs mit Untermaßprobenergebnissen erfasst. Zur Schaffung einer geeigneten aktuellen Datenbasis wurden an ISO-V-Proben der Dicken 2,5, 5,0, 7,5 und 10,0 mm aus vier aktuellen Baustählen KV2-T-Kurven ermittelt. Es wurden unterschiedliche Vorgehensweisen zur Kurvenanpassung und Festlegung von Übergangstemperaturen praktiziert. Ferner kamen verfügbare Ansätze zur Skalierung von Untermaßprobenergebnissen auf die Werte von Normalproben zur Anwendung. Das Ausmaß des Probendickeneffektes ist werkstoff- und temperaturabhängig. Im Bereich der Werkstoffprüfung ist akzeptiert, dass die Ergebnisse von Normal- und Untermaß-proben nicht ohne Weiteres ineinander überführt werden können. Der Stand der Produktnormung und der Regelwerke ist jedoch im besten Falle als unzureichend, vielfach jedoch schlicht als falsch zu bezeichnen. In einem weiten anwendungsrelevanten Temperaturbereich werden hier sogar deutlich nicht-konservative Skalierungsergebnisse geliefert. Die betroffenen Produkt-normenreihen und Regelwerke müssen überarbeitet werden.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022: Werkstoffe und Bauteile auf dem Prüfstand, Prüftechnik – Kennwertermittlung – Schadensvermeidung
CY - Dresden, Germany
DA - 27.10.2022
KW - Kerbschlagbiegeversuch, Untermaßproben, Normalproben, Skalierung von Ergebnissen
PY - 2022
SP - 1
EP - 6
PB - Deutsche Gesellschaft für Materialkunde (DGM)
CY - Sankt Augustin
AN - OPUS4-56155
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Zur Frage der Verwendung von Untermaßprobenergebnissen des Kerbschlagbiegeversuchs – eine ernüchternde Bilanz
N2 - Der Kerbschlagbiegeversuch ist seit der ersten Hälfte des letzten Jahrhunderts standardisiert und seit langem als Prüfverfahren international genormt. Weltweit sind zu garantierende Werte der Kerbschlagenergie (KV) und Übergangstemperaturen (TÜ) in Produktnormen und Regelwerken festgelegt. Unter bestimmten Bedingungen besteht dabei die Option, statt Normalproben Untermaßproben zu prüfen. Im Rahmen einer Untersuchung der BAM wurde der aktuelle Status von Prüf- und Produktnormen sowie Regelwerken zur Bewertung der Bauteilintegrität hinsichtlich ihres Umgangs mit Untermaßprobenergebnissen erfasst. Zur Schaffung einer geeigneten aktuellen Datenbasis wurden an ISO-V-Proben der Dicken 2,5, 5,0, 7,5 und 10,0 mm aus vier aktuellen Baustählen KV2-T-Kurven ermittelt. Es wurden unterschiedliche Vorgehensweisen zur Kurvenanpassung und Festlegung von Übergangstemperaturen praktiziert. Ferner kamen verfügbare Ansätze zur Skalierung von Untermaßprobenergebnissen auf die Werte von Normalproben zur Anwendung. Das Ausmaß des Probendickeneffektes ist werkstoff- und temperaturabhängig. Im Bereich der Werkstoffprüfung ist akzeptiert, dass die Ergebnisse von Normal- und Untermaß-proben nicht ohne Weiteres ineinander überführt werden können. Der Stand der Produktnormung und der Regelwerke ist jedoch im besten Falle als unzureichend, vielfach jedoch schlicht als falsch zu bezeichnen. In einem weiten anwendungsrelevanten Temperaturbereich werden hier sogar deutlich nicht-konservative Skalierungsergebnisse geliefert. Die betroffenen Produkt-normenreihen und Regelwerke müssen überarbeitet werden.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Skalierung von Ergebnissen
KW - Kerbschlagbiegeversuch
KW - Untermaßproben
KW - Normalproben
PY - 2022
AN - OPUS4-56156
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
A1 - Breidung, Marc
A1 - Kiyak, Yusuf
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Küppers, M.
T1 - Aspekte der analytischen bruchmechanischen Bauteilbewertung
N2 - Am Beispiel eines abgesetzten zylindrischen Bauteils (Achsschenkel) werden Probleme der analytischen bruchmechanischen Bauteilbewertung diskutiert. Als Basis-philosophie wird ein Fail Safe-Kriterium (kontrolliertes Versagen) angesetzt. Die Forderung ist, dass sich der Achsschenkel, bevor er bricht, in einem Ausmaß plastisch verformen kann, bei dem der Fahrer bemerkt, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Um das zu gewährleisten, muss der Werkstoff einen bestimmten Riss-widerstand aufweisen. Dazu werden im hier vorgestellten ersten Teil des Projektes mittels FEM Rissspitzenbeanspruchungen in Abhängigkeit von der Auslenkung des Zylinders und angenommener Rissgrößen ermittelt. Diese finden als Zielgrößen in der weiteren Analyse Anwendung. Da eine einfach umzusetzende Lösung angestrebt wird, werden zusätzlich analytische Rechnungen an Ersatzgeometrien (halbunendliche Platte und Vollzylinder), aber mit den realen Spannungen am Bauteil durchgeführt. Es zeigt sich, dass die Ergebnisse wegen des Steifigkeitsunterschieds zwischen Bauteil und Ersatzgeometrie unvertretbar konservativ sind. Alternativ wird ein hybrides Konzept vorgestellt, für das die Modellparameter mittels FEM bestimmt werden. Es liefert sehr genaue Ergebnisse. Im Rahmen der analytischen Rechenvorschrift können die Lösungen auf andere Werkstoffe übertragen werden, ohne dass zusätzliche FEM-Analysen notwendig sind.
T2 - 54. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Online meeting
DA - 22.02.2022
KW - FEM
KW - Bauteilbewertung
KW - Fail-safe
KW - Analytisches Modell
PY - 2022
DO - https://doi.org/10.48447/Br-2022-BB
VL - 254
SP - 1
EP - 11
PB - DVM
CY - Berlin
AN - OPUS4-54406
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - BOOK
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
T1 - Dynamics of Composite Materials
N2 - Historically, to tune the properties of a polymer or more general soft matter systems by a second phase is not a new concept and dates back to the 40s of the last century. Beside some successes, the improvement of the properties remained somehow limited. The expectations of the enhancement of the properties of composites changed by the developments of Toyota Central research in the 1990s. It was shown that the incorporation of 5 vol% exfoliated layers of a clay system into a polymer leads to a strong improvement of the mechanical and thermal properties. This discovery stimulated a broad research interest of both fundamental and applied character. Today, polymer-based nanocomposites have reached a billion-dollar global market. The corresponding applications span from components for transportation, commodity plastics with enhanced barrier and/or flame retardancy characteristics, to polymers with electrical properties for shielding, electronics, sensors, and solar cells as well as to live science. Important fields are filled rubbers, reinforced thermoplastics, or thermosets for automotive, aircraft/space and marine industries, but also membranes for separation processes as well as barrier layers, just to mention a few.
For a variety of applications, the molecular mobility in nanocomposites is of great importance. This concerns the molecular mobility needed to form a percolating filler network in rubbers used in tires or in composites employed in electric shielding applications. In general, it is also essential for processing polymer-based nanocomposites. Furthermore, separation processes in composite materials for membranes require a certain molecular mobility. This also concern nanodielectrics used in electrical applications or sensors where the mobility of charge carriers can be related to the fluctuations of molecular groups etc. Finally, the molecular mobility can be taken as probe for structure on a molecular scale.
Broadband dielectric spectroscopy is a powerful tool to investigate the molecular mobility in polymer systems. It is due to the extremely broad frequency and sensitivity range that can be covered by this technique. Information about localized and cooperative molecular fluctuations, polarization effects at interfaces, as well as charge transport processes can be deduced. Therefore, this book focusses on broadband dielectric spectroscopy of composite materials. Moreover, the dielectric studies are accompanied by mechanical spectroscopy, advanced calorimetry, NMR techniques, as well as transmission electron microscopy and X-ray scattering investigations.
Besides a brief introduction to (nano)composites, the book aims to address fundamental aspects of the molecular mobility in this innovative group of materials. Selected examples with scientific interest and some cases with high industrial impact were chosen. Due to the breadth of the subject, unfortunately not all topics could be addressed in detail, such as processing for instance.
Berlin, Andreas Schönhals
July 2021 Paulina Szymoniak
KW - Composite materials
KW - Nanocomposites
PY - 2022
SN - 978-3-030-89722-2
SN - 978-3-030-89723-9
DO - https://doi.org/10.1007/978-3-030-89723-9
VL - 2022
SP - 1
EP - 375
PB - Springer Nature
CY - Cham, Switzerland
AN - OPUS4-54538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
A1 - Abbasi, Behboud
T1 - On the question of how to analyze and apply Charpy pendulum impact test results correctly - Shortcomings in corresponding procedures and standards
N2 - This paper is focused on the approximation of absorbed Charpy impact energy-temperature curves (KV-T) and the management of sub-size test piece results in Charpy pendulum impact tests. Both subjects are frequently underestimated but may have a strong impact on the assessment of product quality and structural integrity. The status of related test standards, product standards, structural integrity assessment procedures and corresponding research is reviewed.
It is concluded that the state of regulation is partly insufficient and wrong. There is a wide gap between the state of knowledge in the field of materials testing and the requirements of product standards and structural integrity assessment procedures. The present paper aims at boosting and supporting the necessary discussion among the parties involved to raise the level of technical safety. Correspondingly, a large experimental database was created by Charpy impact testing of popular modern structural Steels with nominal yield strength from 235 MPa to 960 MPa. KV-T data were generated using test pieces with thicknesses between 2.5 mm and 10 mm. Different strategies for KV-T curve fitting, definition of transition temperatures, as well as upper and lower shelf energy levels were followed, and different scaling procedures were applied to the sub-size test piece results. The results show that proportional scaling of sub-size to full-size test piece results in terms of KV should be disallowed because it is a wrong approach.
Regulations still incorporating such procedures should be revised as soon as possible. Existing nonproportional scaling and conversion procedures were applied. The results obtained illustrate that neither an overall nor consistent conservatism nor an adequate conservatism level can be achieved. In summary, the standardizing bodies should enforce the discussion to revise relevant test standards considering more precise specifications on Charpy data fitting. Furthermore, proposals are made for an improved management of sub-size test piece results.
KW - Structural integrity assessment procedure
KW - Charpy pendulum impact test
KW - Sub-size test piece
KW - Standard test piece
KW - Curve fitting
KW - Conversion of results
KW - Absorbed energy
KW - Transition temperature
KW - Steel
KW - Test standard
KW - Product standard
PY - 2022
DO - https://doi.org/10.1520/JTE20210781
SN - 0090-3973
VL - 50
IS - 4
SP - 2268
EP - 2293
PB - American Society for Testing and Materials (ASTM)
CY - West Conshohocken, PA
AN - OPUS4-55172
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jungnickel, R.
A1 - Mirabella, Francesca
A1 - Stockmann, Jörg Manfred
A1 - Radnik, Jörg
A1 - Balasubramanian, K.
T1 - Graphene‑on‑gold surface plasmon resonance sensors resilient to high‑temperature annealing
N2 - Gold films coated with a graphene sheet are being widely used as sensors for the detection of label-free binding interactions using surface plasmon resonance (SPR). During the preparation of such sensors, it is often essential to subject the sensor chips to a high-temperature treatment in order to ensure a clean graphene surface. However, sensor chips used currently, which often use chromium as an adhesion promoter, cannot be subjected to temperatures above 250 °C, because under such conditions, chromium is found to reorganize and diffuse to the surface, where it is easily oxidized, impairing the quality of SPR spectra. Here we present an optimized preparation strategy involving a three-cycle tempering coupled with chromium (oxide) etching, which allows the graphene-coated SPR chips to be annealed up to 500 °C with little deterioration of the surface morphology. In addition, the treatment delivers a surface that shows a clear enhancement in spectral response together with a good refractive index sensitivity. We demonstrate the applicability of our sensors by studying the kinetics of avidin–biotin binding at different pH repeatedly on the same chip. The possibility to anneal can be exploited to recover the original surface after sensing trials, which allowed us to reuse the sensor for at least six cycles of biomolecule adsorption.
KW - Surface plasmon resonance
KW - Graphene
KW - Sensing
KW - Surface regeneration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564585
DO - https://doi.org/10.1007/s00216-022-04450-4
SN - 1618-2642
SP - 1
EP - 7
PB - Springer
AN - OPUS4-56458
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nickl, Philip
A1 - Hilal, T.
A1 - Olal, D.
A1 - Donskyi, Ievgen
A1 - Radnik, Jörg
A1 - Ludwig, K.
A1 - Haag, R.
T1 - A New Support Film for Cryo Electron Microscopy Protein Structure Analysis Based on Covalently Functionalized Graphene
N2 - Protein adsorption at the air–water interface is a serious problem in cryogenic electron microscopy (cryoEM) as it restricts particle orientations in the vitrified ice-film and promotes protein denaturation. To address this issue, the preparation of a graphene-based modified support film for coverage of conventional holey carbon transmission electron microscopy (TEM) grids is presented. The chemical modification of graphene sheets enables the universal covalent anchoring of unmodified proteins via inherent surface-exposed lysine or cysteine residues in a one-step reaction. Langmuir–Blodgett (LB) trough approach is applied for deposition of functionalized graphene sheets onto commercially available holey carbon TEM grids. The application of the modified TEM grids in single particle analysis (SPA) shows high protein binding to the surface of the graphene-based support film. Suitability for high resolution structure determination is confirmed by SPA of apoferritin. Prevention of protein denaturation at the air–water interface and improvement of particle orientations is shown using human 20S proteasome, demonstrating the potential of the support film for structural biology.
KW - Functionalized graphene
KW - Transmission electron microsocpy
KW - Protein structure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566443
DO - https://doi.org/10.1002/smll.202205932
SN - 1613-6810
SP - 2205932
PB - Wiley VCH
AN - OPUS4-56644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Gezielte Werkstoffprüfung zur fail-safe-Bauteilauslegung am Beispiel eines Achsschenkels
N2 - Bei der Auslegung von Achsschenkeln für Nutzfahrzeuge wird für den Überlastfall ein fail-safe-Kriterium (kontrolliertes Versagen) als Basisphilosophie angesetzt. Gefordert wird, dass sich der Achsschenkel auch unter Akzeptanz begrenzten Risswachstums hinreichend elastisch-plastisch verformen kann, ohne dass es zum Bruch kommt. Der Fahrer soll anschließend anhand der bleibenden Verformungen bemerken können, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Eine Voraussetzung für dieses Bauteilverhalten ist eine hinreichende Bruchzähigkeit des Werkstoffs. Diese, wie auch die Rissspitzenbeanspruchung, müssen ermittelt wer-den, um den bruchmechanischen Sicherheitsnachweis führen zu können. Zur Ermittlung der mechanisch-technologischen und bruchmechanischen Werkstoffeigenschaften wurde ein Prüfkonzept entwickelt, bei dem die Proben an der potenziell kritischen Stelle direkt aus den geschmiedeten Achsschenkeln entnommen werden. Die experimentelle Werkstoffcharakterisierung bildet dann die Beanspruchungsbedingungen beim Überlastereignis ab. Im Rahmen der Produktion stehen jedoch nur Kerbschlagarbeitswerte zur Verfügung und aufwändige bruchmechanische Versuche sollen vermieden werden. Deshalb wurde eine Korrelation zur Abschätzung der vorhandenen Bruchzähigkeit aus der Kerbschlagarbeit herangezogen. Es ergibt sich eine Ergebnismatrix, die die Einflussgrößen Versagenswahrscheinlichkeit, Temperatur und Bruchzähigkeit verknüpft. Abschließend wird ein erster Vergleich der abgeschätzten mit den experimentell ermittelten Bruchzähigkeitswerten gezogen. Dieser weist aus, dass die abgeschätzten Werte geringfügig konservativ sind.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Korrelation
KW - Achsschenkel
KW - Fail-safe
KW - Bruchmechanische Auslegung
KW - Kerbschlagarbeit
PY - 2022
AN - OPUS4-56153
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Pauw, Brian Richard
T1 - Just a minute: X-ray scattering
N2 - An extremely brief summary of what X-ray scattering can do for you (X-ray scattering encompasses small-angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS/XRD), amongst others). See my other videos for more detailed explanations on sample selection, data correction, data analysis, etc.
KW - X-ray scattering
KW - Introduction
KW - Materials science
KW - Nanostructure investigation
KW - MOUSE
PY - 2022
UR - https://www.youtube.com/watch?v=jWWNQyaCTHA
DO - https://doi.org/10.26272/opus4-55768
PB - YouTube, LLC
CY - San Bruno, CA, USA
AN - OPUS4-55768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chowdhary, S.
A1 - Schmidt, R. F.
A1 - Sahoo, A. K.
A1 - tom Dieck, T.
A1 - Hohmann, T.
A1 - Schade, B.
A1 - Brademann-Jock, Kerstin
A1 - Thünemann, Andreas
A1 - Netz, R. R.
A1 - Gradzielski, M.
A1 - Koksch, B.
T1 - Rational design of amphiphilic fluorinated peptides: Evaluation of self-assembly properties and hydrogel formation
N2 - Advanced peptide-based nanomaterials composed of self-assembling peptides (SAPs) are of emerging interest in pharmaceutical and biomedical applications. The introduction of fluorine into peptides, in fact, offers unique opportunities to tune their biophysical properties and intermolecular interactions. In particular, the degree of fluorination plays a crucial role in peptide engineering as it can be used to control the characteristics of fluorine-specific interactions and, thus, peptide conformation and self-assembly. Here, we designed and explored a series of amphipathic peptides by incorporating the fluorinated amino acids (2S)-4-monofluoroethylglycine (MfeGly), (2S)-4,4-difluoroethylglycine (DfeGly) and (2S)-4,4,4-trifluoroethylglycine (TfeGly) as hydrophobic components. This approach enabled studying the impact of fluorination on secondary structure formation and peptide self-assembly on a systematic basis. We show that the interplay between polarity and hydrophobicity, both induced differentially by varying degrees of side chain fluorination, does affect peptide folding significantly. A greater degree of fluorination promotes peptide fibrillation and subsequent formation of physical hydrogels in physiological conditions. Molecular simulations revealed the key role played by electrostatically driven intra-chain and inter-chain contact pairs that are modulated by side chain fluorination and give insights into the different self-organization behaviour of selected peptides. Our study provides a systematic report about the distinct features of fluorinated oligomeric peptides with potential applications as peptide-based biomaterials.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Amyloid
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553504
DO - https://doi.org/10.1039/D2NR01648F
SN - 2040-3364
VL - 14
IS - 28
SP - 10176
EP - 10189
PB - Royal Society of Chemistry
AN - OPUS4-55350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Navarro, L.
A1 - Thünemann, Andreas
A1 - Yokosawa, T.
A1 - Spiecker, E.
A1 - Klinger, D.
T1 - Regioselective Seeded Polymerization in Block Copolymer Nanoparticles: Post-Assembly Control of Colloidal Features
N2 - Post-assembly modifications are efficient tools to adjust colloidal features of block copolymer (BCP) particles. However, existing methods often address particle shape, morphology, and chemical functionality individually. For simultaneous control, we transferred the concept of seeded polymerization to phase separated BCP particles. Key to our approach is the regioselective polymerization of (functional) monomers inside specific BCP domains. This was demonstrated in striped PS-b-P2VP ellipsoids. Here, polymerization of styrene preferably occurs in PS domains and increases PS lamellar thickness up to 5-fold. The resulting asymmetric lamellar morphology also changes the particle shape, i.e., increases the aspect ratio. Using 4-vinylbenzyl azide as co-monomer, azides as chemical functionalities can be added selectively to the PS domains. Overall, our simple and versatile method gives access to various multifunctional BCP colloids from a single batch of pre-formed particles.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
KW - Polymer
KW - Nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557246
DO - https://doi.org/10.1002/anie.202208084
SN - 1433-7851
VL - 61
IS - 35
SP - 1
EP - 11
PB - Wiley
CY - Weinheim
AN - OPUS4-55724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, M. B.
A1 - Fahrenson, C.
A1 - Givelet, L.
A1 - Herrmann, T.
A1 - Loescher, K.
A1 - Böhmert, L.
A1 - Thünemann, Andreas
A1 - Braeuning, A.
A1 - Sieg, H.
T1 - Beyond microplastics ‑ investigation on health impacts of submicron and nanoplastic particles after oral uptake in vitro
N2 - The continuously increasing use of plastics is supposed to result in a rising exposure of MNPs to humans. Available data on human health risks of microplastics after oral uptake increased immensely in the past years and indicates very likely only low risks after oral consumption. Concerning nanoplastics, uptake, transport and potential adverse effects after oral uptake are less well understood. This study aims to investigate differences between microplastic particles and particles in the submicron- and nanoscaled size derived from food-relevant polymers with a particle size range consistent with higher potential for cellular uptake, fate, and effects when applied to human intestinal and liver cells. This work includes the development of cellular and subcellular detection methods for synthetic polymeric particles in the micro- and nanometer-range, using Scanning Electron Microscopy, Small-Angle X-ray and Dynamic Light Scattering methods, Asymmetric Flow Field Flow Fractionation, octanol-water fractionation, fluorescence microscopy and flow cytometry. Polylactic acid (250 nm and 2 μm (polydisperse)), melamine formaldehyde (366 nm) and polymethylmethacrylate (25 nm) were thoroughly characterized. The submicro- and nanoplastic test particles showed an increased uptake and transport quantity through intestinal cells. Both types of particles resulted in observed differences of uptake behavior, most likely influenced by different lipophilicity, which varied between the polymeric test materials. Toxic effects were detected after 24 h only in overload situations for the particles in the submicrometer range. This study provides further evidence for gastrointestinal uptake of submicro- and nanoplastics and points towards differences regarding bioavailability between microplastics and smaller plastic particles that may result following the ingestion of contaminated food and beverages. Furthermore, the results reinforce the importance for studying nanoplastics of different materials of varying size, surface properties, polymer composition and hydrophobicity.
KW - Small-angle X-ray scattering
KW - SAXS
KW - nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550741
DO - https://doi.org/10.1186/s43591-022-00036-0
VL - 2
SP - 1
EP - 19
PB - Springer Nature
AN - OPUS4-55074
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Navarro, L.
A1 - Thünemann, Andreas
A1 - Klinger, D.
T1 - Solvent Annealing of Striped Ellipsoidal Block Copolymer Particles: Reversible Control over Lamellae Asymmetry, Aspect Ratio, and Particle Surface
N2 - Solvent annealing is a versatile tool to adjust the shape and morphology of block copolymer (BCP) particles. During this process, polar solvents are often used for block-selective swelling. However, such water-miscible solvents can induce (partial) solubilization of one block in the surrounding aqueous medium, thus, causing complex structural variations and even particle disassembly. To reduce the complexity in morphology control, we focused on toluene as a nonpolar polystyrene-selective solvent for the annealing of striped polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) ellipsoids. The selective stretching of PS chains produces unique asymmetric lamellae structures, which translate to an increase in the particle aspect ratio after toluene evaporation. Complete reversibility is achieved by changing to chloroform as a nonselective solvent. Moreover, surfactants can be used to tune block-selective wetting of the particle surface during the annealing; for example, a PS shell can protect the internal lamellae structure from disassembly. Overall, this versatile postassembly process enables the tailoring of the structural features of striped colloidal ellipsoids by only using commercial BCPs and solvents.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticle
KW - Polymer
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543731
DO - https://doi.org/10.1021/acsmacrolett.1c00665
VL - 11
IS - 3
SP - 319
EP - 335
PB - American Chemical Society
AN - OPUS4-54373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saloga, Patrick E. J.
A1 - Rybak, Tina
A1 - Thünemann, Andreas
T1 - Microwave-Assisted Synthesis of ZnO Nanoparticles: Phase Transfer to Water
N2 - Herein, a simple one-pot procedure is reported to obtain aqueous zinc oxide (ZnO) nanoparticle dispersions from ZnO nanoparticles dispersed in cyclohexane. In the process, polyoxyethylene (20) sorbitan monooleate (polysorbate 80, Tween 80) functions as a phase transfer agent and colloidal stabilizer. The particles grow in a defined manner during the transfer, presumably via coalescence. The final particle radii are tuneable in the range from 2.3 ± 0.1 nm to 5.7 ± 0.1 nm depending on the incubation time of the dispersion at 90 °C. Small-angle X-ray scattering is employed to determine the particle radius distributions before and after phase transfer. The larger ZnO particle radii are associated with a redshift of the optical bandgap and luminescence emission, as expected for semiconductor nanoparticles. The particles presented here exhibit a relative size distribution width of 20%, rendering them attractive for applications in, e.g., biology or catalysis. The latter application is demonstrated at the photocatalytic degradation of methylene blue dye.
KW - SAXS
KW - Small-angle X-ray scattering
KW - nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551502
DO - https://doi.org/10.1002/adem.202101276
VL - 24
IS - 6
SP - 1
EP - 7
PB - Wiley
AN - OPUS4-55150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - Aqueous Dispersions of polypropylene as possible reference material for nanoplastics
N2 - Plastic debris in micron and nanometer scale pollutes the nature all over the world. The potential dangers of these pollutants remain unpredictable. While risk assessment studies on microplastics are already popular, nanoplastic has not yet reached the same focus of investigation. The reason for this difference is simple: There is a "methodological gap" in the analytics of plastic particles with a diameter smaller than 1 µm. Submicron and nanoplastic particles are currently not detectable in environmental matrices. Therefore, it is important for researchers to have a well-characterized nanoplastic material, that serves as a reference for nanoplastics found in nature.
Our aim was to synthesize nanoplastics made from the most common used plastics such as polypropylene (PP). We found an easy way to form nanoparticles consisting of PP (nano-PP), adapting and improving the method presented for polystyrene (PS). Nano-PP was formed via a top-down method where the polymer was dispersed to acetone and then transferred to water. No additional surfactant is needed to obtain a dispersion which is stable for more than 35 weeks.
The success of forming nanoplastics and their size was detected via scattering methods, predominantly dynamic light scattering (DLS). The chemical analysis of the nanoplastics was performed via Fourier Transform Infrared spectroscopy. To examine the good stability of the nanoparticles, zeta potential measurements were performed, which revealed zeta potentials of -30 to -40 mV.
T2 - European Polymer Congress 2022
CY - Prag, Czechia
DA - 26.06.2022
KW - Nanoplastic
PY - 2022
AN - OPUS4-55960
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieg, H.
A1 - Klusmann, L.
A1 - Ellermann, A. L.
A1 - Böhmert, L.
A1 - Thünemann, Andreas
A1 - Braeuning, A.
T1 - Counterions determine uptake and effects of aluminum in human intestinal and liver cells
N2 - Aluminum (Al) is highly abundant in the biosphere and can occur in different physico-chemical states. It is present in human food and undergoes transitions between dissolved and particulate species during the passage of the gastrointestinal tract. Moreover, in a complex matrix such as food different inorganic and organic counterions can affect the chemical behavior of Al following oral uptake.
In this work, the effects of different counterions, namely chloride, citrate, sulfate, lactate and acetylacetonate, on Al uptake and toxicity in the human intestine are studied. The respective Al salts showed different dissolution behavior in biological media and formed nanoscaled particles correlating in reverse with the amount of their dissolved fraction. The passage through the intestinal barrier was studied using a Caco-2 Transwell® system, showing counterion-dependent variance in cellular uptake and transport. In addition, Al toxicity was investigated using Al species (Al3+, metallic Al0 and oxidic γAl2O3 nanoparticles) and counterions individually or in mixtures on Caco-2 and HepG2 cells. The strongest toxicity was observed using a combination of Al species, depending on solubility, and the lipophilic counterion acetylacetonate. Notably, only the combination of both led to toxicity, while both substances individually did not show toxic effects. A toxification of previously non-toxic Al-species by the presence of acetylacetonate is shown here for the first time. The dependency on the concentration of free Al ions was demonstrated using sodium hydrogen phosphate, which was able to counteract the toxic effects by complexing free Al ions.
These findings, using Al salts as an example for a common food contaminant, underline the importance of a consideration of the chemical properties of human nutrition, especially dissolution and hydrophobicity, which can significantly influence the cellular uptake and effects of xenobiotic substances.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanoparticle
PY - 2022
DO - https://doi.org/10.1016/j.tiv.2021.105295
VL - 79
SP - 1
EP - 7
PB - Elsevier
AN - OPUS4-54110
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dubey, A.
A1 - Hon Keat, C.
A1 - Shvartsman, V.
A1 - Yusenko, Kirill
A1 - Escobar, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Hagemann, U.
A1 - Kovalenko, S.
A1 - Stächler, J.
A1 - Lupascu, D.
T1 - Mono-, Di-, and Tri-valent Cation Doped BiFe0.95Mn0.05O3 Nanoparticles: Ferroelectric Photocatalysts
N2 - The ferroelectricity of multivalent co-doped Bismuth ferrite (BiFeO3; BFO) nanoparticles (NPs) is revealed and utilized for light photocatalysis exploiting their narrow electronic band gap. The photocatalytic activity of ferroelectric photocatalysts BiFe0.95Mn0.05O3 (BFM) NPs and mono-, di-, or tri-valent cations (Ag+, Ca2+, Dy3+; MDT) co-incorporated BFM NPs are studied under ultrasonication and in acidic conditions. We find that such doping enhances the photocatalytic activity of the ferroelectric NPs approximately three times. The correlation of the photocatalytic activity with structural, optical, and electrical properties of the doped NPs is established. The increase of spontaneous polarization by the mono- and tri-valent doping is one of the major factors in enhancing the photocatalytic performance along with other factors such as stronger light absorption in the visible range, low recombination rate of charge carriers and larger surface area of NPs. A-site doping of BFO NPs by divalent elements suppresses the polarization, whereas trivalent (Dy3+) and monovalent (Ag+) cations provide an increase of polarization. The depolarization field in these single domain NPs acts as a driving force to mitigate recombination of the photoinduced charge carriers.
KW - Piezoresponse
KW - Bismuth Ferrite
KW - Nanoparticles
KW - Photocatalysis
KW - Ferroelectric
KW - Polarization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557230
DO - https://doi.org/10.1002/adfm.202207105
SN - 1616-301X
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-55723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Sebastian
A1 - Bertmer, M.
A1 - Gluth, Gregor
T1 - Sol–gel synthesis and characterization of lithium aluminate (L–A–H) and lithium aluminosilicate (L–A–S–H) gels
N2 - Hydrous lithium aluminosilicate (L–A–S–H) and lithium aluminate (L–A–H) gels are candidate precursors for glass-ceramics and ceramics with potential advantages over conventional processing routes. However, their structure before calcination remained largely unknown, despite the importance of precursor structure on the properties of the resulting materials. In the present study, it is demonstrated that L–A–S–H and L–A–H gels with Li/Al ≤ 1 can be produced via an organic steric entrapment route, while higher Li/Al ratios lead to crystallization of gibbsite or nordstrandite. The composition and the structure of the gels was studied by thermogravimetric analysis, X-ray diffraction, 27Al and 29Si magic-angle spinning nuclear magnetic resonance, and Raman spectroscopy. Aluminium was found to be almost exclusively in six-fold coordination in both the L–A–H and the L–A–S–H gels. Silicon in the L–A–S–H gels was mainly in Q4 sites and to a lesser extent in Q3 sites (four-fold coordination with no Si–O–Al bonds). The results thus indicate that silica-rich and aluminium-rich domains formed in these gels.
KW - Lithium aluminosilicates
KW - Raman spectroscopy
KW - Sol-gel
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558756
DO - https://doi.org/10.1111/ijac.14187
SN - 1546-542X
VL - 19
IS - 6
SP - 3179
EP - 3190
PB - Wiley
AN - OPUS4-55875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - PP Nanoplastics Dispersed In Water As Reference Materials
N2 - Plastic debris in micron and nanometer scale pollutes the nature all over the world. The potential dangers of these pollutants remain unpredictable. While risk assessment studies on microplastic are already popular, nanoplastic has not yet reached the same focus of investigation. The reason for this difference is simple: There is a “methodological gap” in the analytics of plastic particles with a diameter smaller than 1 µm. Submicron and nano plastic particles are currently not detectable in environmental matrices. Therefore, it is important for researchers to have a well-characterized nanoplastic material, that serves as a reference for nanoplastic found in nature.
Our aim was to synthesize nanoplastics made from the most common used plastics, starting with polypropylene (PP). We found an easy way to form nanoparticles consisting of PP (nano-PP), adapting and improving the method presented for polystyrene (PS). PP was dispersed to acetone and then transferred to water. No additional surfactant is needed to obtain a dispersion which is stable for more than 35 weeks. The
The success of forming nanoplastics and their size was detected via scattering methods, predominantly dynamic light scattering (DLS). To examine the good stability of the nanoparticles, zeta potential measurements were performed, which revealed zeta potentials of -30 to -40 mV.
This method is repeatable and well suited to produce reference material, as which we propose our prepared particles, based on a homogeneity study, that we performed, following the ISO Guide 35 for reference materials.
T2 - Prague Meeting on Macromolecules 2022
CY - Prag, Czechia
DA - 24.07.2022
KW - Nanoplastic
KW - Reference material
PY - 2022
AN - OPUS4-55961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - Aqueous dispersions of polypropylene: towards referencematerials for nanoplastics characterization
N2 - Plastic pollution in the environment is a rising concern for the health of our planet. The plastic litter that pollutes our environment leads to microplastic particles. They can be found (nearly) everywhere. The processes that lead to microplastic can also form nanoplastic particles, which have a size below 1 µm. Because of the small size they can penetrate tissue more easily. Only few risk assessment studies of nanoplastics were carried out so far.
Using polystyrene (PS) nanoparticles to test effects on organisms is easy because it is commercially available. However, this falls a little short, as the polyolefins i.e., polypropylene (PP) and polyethylene (PE), are produced in a larger proportion than PS. Moreover, these plastics are mainly used for disposable products, which means that they also account for a large proportion of plastic waste. Therefore, the percentage of polyolefins in environmental nanoplastic is presumably high. It is important to test the toxicological effects also with nanoplastics made of PP and PE to have more realistic results.
Herein, we present an easy and repeatable method to prepare an aqueous dispersion of polypropylene nanoplastics (nano-PP). They are stabilized electrostatically, resulting in a strongly negative zeta potential of -43 mV (± 2 mV) and making no surfactant necessary to keep the dispersion stable.
The size and the size distribution were determined via Dynamic Light Scattering (DLS) and gives a hydrodynamic diameter of 180.5 nm (± 5.8 nm) and a PDI of 0.084 (± 0.023).
Finally, ca. 480 bottles of the dispersion with a volume of 10 mL each were prepared to serve as a potential reference material for further testing of detection methods or risk assessments.
T2 - International Conference on Microplastic Pollution in the Mediterranean Sea
CY - Neapel, Italy
DA - 25.09.2022
KW - Nanoplastic
PY - 2022
AN - OPUS4-55963
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes, Bruna F.
A1 - Prokop, Martin
A1 - Bystron, Tomas
A1 - Loukrakpam, Rameshwori
A1 - Melke, Julia
A1 - Lobo, Carlos M. S.
A1 - Fink, Michael
A1 - Zhu, Mengshu
A1 - Voloshina, Elena
A1 - Kutter, Maximilian
A1 - Hoffmann, Hendrik
A1 - Yusenko, Kirill V.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, Bettina
A1 - Bouzek, Karel
A1 - Paulus, Beate
A1 - Roth, Christina
T1 - Following Adsorbed Intermediates on a Platinum Gas Diffusion Electrode in H3PO3-Containing Electrolytes Using In Situ X-ray Absorption Spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalystwith H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate Proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - H3PO3,
KW - Δμ XANES
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - American Chemical Society (ACS)
AN - OPUS4-64733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - C. Pardo Pérez, L.
A1 - Arndt, A.
A1 - Stojkovikj, S.
A1 - Y. Ahmet, I.
A1 - T. Arens,, J.
A1 - Dattila, F.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Davies, V.
A1 - Höflich, K.
A1 - Köhnen, E.
A1 - Tockhorn, P.
A1 - Golnak, R.
A1 - Xiao, J.
A1 - Schuck, G.
A1 - Wollgarten, M.
A1 - López, N.
A1 - T. Mayer, M.
T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy
N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts.
KW - Electrochemical CO2 conversion
KW - Cu catalysts
KW - X-ray absorption spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116
DO - https://doi.org/10.1002/aenm.202103328
SN - 1614-6832
VL - 12
IS - 5
SP - 2103328
PB - Wiley-VCH GmbH
AN - OPUS4-54711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Taylor, J.
A1 - Thakur, S.
A1 - Radu, F.
A1 - Weschke, E.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Xiao, B.
A1 - Savan, A.
A1 - Yusenko, Kirill
A1 - Ludwig, A.
T1 - Local structure and magnetic properties of a nanocrystalline Mn-rich Cantor alloy thin film down to the atomic scale
N2 - The huge atomic heterogeneity of high-entropy materials along with a possibility to unravel the behavior of individual components at the atomic scale suggests a great promise in designing new compositionally complex systems with the desired multi-functionality. Herein, we apply multi-edge X-ray absorption spectroscopy (extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and X-ray magnetic circular dichroism (XMCD)) to probe the structural, electronic, and magnetic properties of all individual constituents in the single-phase face-centered cubic (fcc)-structured nanocrystalline thin film of Cr20Mn26Fe18Co19Ni17 (at.%) high-entropy alloy on the local scale. The local crystallographic ordering and component-dependent lattice displacements were explored within the reverse Monte Carlo approach applied to EXAFS spectra collected at the K absorption edges of several constituents at room temperature. A homogeneous short-range fcc atomic environment around the absorbers of each type with very similar statistically averaged interatomic distances (2.54–2.55 Å) to their nearest-neighbors and enlarged structural relaxations of Cr atoms were revealed. XANES and XMCD spectra collected at the L2,3 absorption edges of all principal components at low temperature from the oxidized and in situ cleaned surfaces were used to probe the oxidation states, the changes in the electronic structure, and magnetic behavior of all constituents at the surface and in the sub-surface volume of the film. The spin and orbital magnetic moments of Fe, Co, and Ni components were quantitatively evaluated. The presence of magnetic phase transitions and the co-existence of different magnetic phases were uncovered by conventional magnetometry in a broad temperature range.
KW - Magnetism
KW - High-entropy alloys
KW - Reverse Monte Carlo (RMC)
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS),
KW - X-ray magnetic circular dichroism (XMCD),
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578254
DO - https://doi.org/10.1007/s12274-022-5135-3
SN - 1998-0124
SP - 5626
PB - Springer
AN - OPUS4-57825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Knigge, Xenia
A1 - Andresen, Elina
A1 - Resch-Genger, Ute
A1 - Cant, D.J.H.
A1 - Shard, A.G.
A1 - Clifford, C.A.
T1 - Composition, thickness, and homogeneity of the coating of core–shell nanoparticles—possibilities, limits, and challenges of X-ray photoelectron spectroscopy
N2 - Core–shell nanoparticles have attracted much attention in recent years due to their unique properties and their increasing importance in many technological and consumer products. However, the chemistry of nanoparticles is still rarely investigated in comparison to their size and morphology. In this review, the possibilities, limits, and challenges of X-ray photoelectron spectroscopy (XPS) for obtaining more insights into the composition, thickness, and homogeneity of nanoparticle coatings are discussed with four examples: CdSe/CdS quantum dots with a thick coating and a small core; NaYF4-based upconverting nanoparticles with a large Yb-doped core and a thin Er-doped coating; and two types of polymer nanoparticles with a poly(tetrafluoroethylene) core with either a poly(methyl methacrylate) or polystyrene coating. Different approaches for calculating the thickness of the coating are presented, like a simple numerical modelling or a more complex simulation of the photoelectron peaks. Additionally, modelling of the XPS background for the investigation of coating is discussed. Furthermore, the new possibilities to measure with varying excitation energies or with hard-energy X-ray sources (hard-energy X-ray photoelectron spectroscopy) are described. A discussion about the sources of uncertainty for the determination of the thickness of the coating completes this review.
KW - X-ray spectroscopy
KW - Nanoparticles
KW - Spectroscopy / Instrumentation
KW - Spectroscopy / Theory
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548305
DO - https://doi.org/10.1007/s00216-022-04057-9
VL - 414
IS - 15
SP - 4331
EP - 4345
PB - SpringerNature
AN - OPUS4-54830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Kiyak, Yusuf
A1 - Breidung, Marc
A1 - Baer, Wolfram
A1 - Küppers, M.
ED - Madia, Mauro
T1 - Stiffness/constraint effects in analytical flaw assessment - A technical note
N2 - Using the case study of a fail-safe design criterion for a steering knuckle of a commercial vehicle, the effect of stiffness/constraint on the crack driving force in the component is discussed. The problem arises when assessment procedures such as R6, BS 7910 or SINTAP/FITNET are applied in conjunction with substitute geometries for determining the model parameters K-factor and limit load (or a substitute for the latter), as it is common practice. In the example, the conservatism was so pronounced that this procedure was in fact unusable. A way out could be the finite element-based determination of the model parameters and their use in the analytical framework. This procedure is useful and effective if the finite element-based calculations are used in parameter sensitivity analyses.
KW - Fail-safe design
KW - Fracture resistance
KW - Fracture assessment
KW - Stiffness
KW - Constraint
PY - 2022
DO - https://doi.org/10.1016/j.engfracmech.2022.108728
SN - 0013-7944
IS - 273
SP - 1
EP - 15
PB - Elsevier Science
CY - Kidlington
AN - OPUS4-55544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Aspekte der analytischen bruchmechanischen Bauteilbewertung
N2 - Am Beispiel eines abgesetzten zylindrischen Bauteils (Achsschenkel) werden Probleme der analytischen bruchmechanischen Bauteilbewertung diskutiert. Als Basis-philosophie wird ein Fail Safe-Kriterium (kontrolliertes Versagen) angesetzt. Die Forderung ist, dass sich der Achsschenkel, bevor er bricht, in einem Ausmaß plastisch verformen kann, bei dem der Fahrer bemerkt, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Um das zu gewährleisten, muss der Werkstoff einen bestimmten Riss-widerstand aufweisen. Dazu werden im hier vorgestellten ersten Teil des Projektes mittels FEM Rissspitzenbeanspruchungen in Abhängigkeit von der Auslenkung des Zylinders und angenommener Rissgrößen ermittelt. Diese finden als Zielgrößen in der weiteren Analyse Anwendung. Da eine einfach umzusetzende Lösung angestrebt wird, werden zusätzlich analytische Rechnungen an Ersatzgeometrien (halbunendliche Platte und Vollzylinder), aber mit den realen Spannungen am Bauteil durchgeführt. Es zeigt sich, dass die Ergebnisse wegen des Steifigkeitsunterschieds zwischen Bauteil und Ersatzgeometrie unvertretbar konservativ sind. Alternativ wird ein hybrides Konzept vorgestellt, für das die Modellparameter mittels FEM bestimmt werden. Es liefert sehr genaue Ergebnisse. Im Rahmen der analytischen Rechenvorschrift können die Lösungen auf andere Werkstoffe übertragen werden, ohne dass zusätzliche FEM-Analysen notwendig sind.
T2 - 54. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Online meeting
DA - 22.02.2022
KW - Bauteilbewertung
KW - Fail-safe
KW - Analytisches Modell
KW - FEM
PY - 2022
AN - OPUS4-54408
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bawadkji, O.
A1 - Cherri, M.
A1 - Schäfer, A.
A1 - Herziger, S.
A1 - Nickl, Philip
A1 - Achazi, K.
A1 - Donskyi, Ievgen
A1 - Adeli, M.
A1 - Haag, R.
T1 - One-pot covalent functionalization of 2D black phosphorus by anionic ring opening polymerization
N2 - In this work, a one-pot approach for the covalent functionalization of few-layer black phosphorus (BP) by anionic ring opening polymerization of glycidol to obtain multifunctional BP-polyglycerol (BP-PG) with high amphiphilicity for near-infrared-responsive drug delivery and biocompatibility is reported. Straightforward synthesis in combination with exceptional biological and physicochemical properties designates functionalized BP-PG as a promising candidate for a broad range of biomedical applications.
KW - 2D nanomaterial
KW - Amphiphilicity
KW - Black phosphorus
KW - Hyperbranched
KW - Polyglycerol
KW - Water dispersibility
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568833
DO - https://doi.org/10.1002/admi.202201245
SN - 2196-7350
VL - 9
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56883
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Resch-Genger, Ute
ED - Koch, Matthias
ED - Meermann, Björn
ED - Weller, Michael G.
T1 - Topical collection: Analytical methods and applications in the materials and life sciences
N2 - Current trends in materials and life sciences are flanked by the need to push detection limits to single molecules or single cells, enable the characterization of increasingly complex matrices or sophisticated nanostructures, speed up the time of analysis, reduce instrument complexity and costs, and improve the reliability of data. This requires suitable analytical tools such as spectroscopic, separation and imaging techniques, mass spectrometry, and hyphenated techniques as well as sensors and their adaptation to application-specific challenges in the environmental, food, consumer product, health sector, nanotechnology, and bioanalysis. Increasing concerns about health threatening known or emerging pollutants in drinking water, consumer products, and food and about the safety of nanomaterials led to a new awareness of the importance of analytical sciences. Another important driver in this direction is the increasing demand by legislation, particularly in view of the 17 sustainable development goals by the United Nations addressing clean energy, industry, and innovation, sustainable cities, clean water, and responsible consumption and production. In this respect, also the development of analytical methods that enable the characterization of material flows in production processes and support recycling concepts of precious raw materials becomes more and more relevant. In the future, this will provide the basis for greener production in the chemical industry utilizing recycled or sustainable starting materials.
This makes analytical chemistry an essential player in terms of the circular economy helping to increase the sustainability of production processes. In the life sciences sector, products based on proteins, such as therapeutic and diagnostic antibodies, increase in importance. These increasingly biotechnologically produced functional biomolecules pose a high level of complexity of matrix and structural features that can be met only by highly advanced methods for separation, characterization, and detection. In addition, metrological traceability and target definition are still significant challenges for the future, particularly in the life sciences.
However, innovative reference materials as required for the health and food sector and the characterization of advanced materials can only be developed when suitable analytical protocols are available. The so-called reproducibility crisis in sciences underlines the importance of improved measures of quality control for all kinds of measurements and material characterization. This calls for thorough method validation concepts, suitable reference materials, and regular interlaboratory comparisons of measurements as well as better training of scientists in analytical sciences.
The important contribution of analytical sciences to these developments is highlighted by a broad collection of research papers, trend articles, and critical reviews from these different application fields. Special emphasis is dedicated to often-overlooked quality assurance and reference materials.
T2 - 150 years BAM: Science with impact
CY - Berlin, Germany
DA - 01.01.2021
KW - 150th anniversary
KW - ABC
KW - Analysis
KW - Analytical sciences
KW - BAM
KW - Collection
KW - Environment
KW - Fluorescence
KW - Life sciences
KW - Limit of detection
KW - Material sciences
KW - Method
KW - Nanoparticle
KW - Pollutant
KW - Quality assurance
KW - Reference material
KW - Sensor
KW - Special issue
KW - Bundesanstalt für Materialforschung und -prüfung
KW - Jahrestag
PY - 2022
UR - https://link.springer.com/journal/216/topicalCollection/AC_16a2ef9b81853377e321ef84d9c4a431
SN - 1618-2642
SN - 1618-2650
VL - 414
SP - 4267
EP - 4529
PB - Springer
CY - Berlin
AN - OPUS4-55670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Getenet, M.
A1 - Garcia-Ruiz, J. M.
A1 - Otálora, F.
A1 - Emmerling, Franziska
A1 - Al-Sabbagh, Dominik
A1 - Verdugo-Escamilla, E.
T1 - A comprehensive methodology for monitoring evaporitic mineral precipitation and hydrochemical evolution of saline lakes: The case of Lake Magadi soda brine (East African Rift Valley, Kenya)
N2 - Lake Magadi, East African Rift Valley, is a hyperalkaline and saline soda lake highly enriched in Na+, K+, CO32–, Cl–, HCO3–, and SiO2 and depleted in Ca2+ and Mg2+, where thick evaporite deposits and siliceous sediments have been forming for 100 000 years. The hydrogeochemistry and the evaporite deposits of soda lakes are subjects of growing interest in paleoclimatology, astrobiology, and planetary sciences. In Lake Magadi, different hydrates of sodium carbonate/bicarbonate and other saline minerals precipitate. The precipitation sequence of these minerals is a key for understanding the hydrochemical evolution, the paleoenvironmental conditions of ancient evaporite deposits, and industrial crystallization. However, accurate determination of the precipitation sequence of these minerals was challenging due to the dependency of the different hydrates on temperature, water activity, pH and pCO2, which could induce phase transformation and secondary mineral precipitation during sample handling. Here, we report a comprehensive methodology applied for monitoring the evaporitic mineral precipitation and hydrochemical evolution of Lake Magadi. Evaporation and mineral precipitations were monitored by using in situ video microscopy and synchrotron X-ray diffraction of acoustically levitated droplets. The mineral patterns were characterized by ex situ Raman spectroscopy, X-ray diffraction, and scanning electron microscopy. Experiments were coupled with thermodynamic models to understand the evaporation and precipitation-driven hydrochemical evolution of brines. Our results closely reproduced the mineral assemblages, patterns, and textural relations observed in the natural setting. Alkaline earth carbonates and fluorite were predicted to precipitate first followed by siliceous sediments. Among the salts, dendritic and acicular trona precipitate first via fractional crystallization─reminiscent of grasslike trona layers of Lake Magadi. Halite/villiaumite, thermonatrite, and sylvite precipitate sequentially after trona from residual brines depleted in HCO3–. The precipitation of these minerals between trona crystals resembles the precipitation process observed in the interstitial brines of the trona layers. Thermonatrite precipitation began after trona equilibrated with the residual brines due to the absence of excess CO2 input. We have shown that evaporation and mineral precipitation are the major drivers for the formation of hyperalkaline, saline, and SiO2-rich brines. The discrepancy between predicted and actual sulfate and phosphate ion concentrations implies the biological cycling of these ions. The combination of different in situ and ex situ methods and modeling is key to understanding the mineral phases, precipitation sequences, and textural relations of modern and ancient evaporite deposits. The synergy of these methods could be applicable in industrial crystallization and natural brines to reconstruct the hydrogeochemical and hydroclimatic conditions of soda lakes, evaporite settings, and potentially soda oceans of early Earth and extraterrestrial planets.
KW - Crystallization
KW - Precipitation
KW - Crystals
KW - Evaporation
KW - Minerals
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546712
DO - https://doi.org/10.1021/acs.cgd.1c01391
SN - 1528-7483
VL - 22
IS - 4
SP - 2307
EP - 2317
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-54671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, A.
A1 - Anis, B.
A1 - Szymoniak, Paulina
A1 - Altmann, Korinna
A1 - Schönhals, Andreas
T1 - Graphene Oxide/Polyvinyl Alcohol–Formaldehyde Composite Loaded by Pb Ions: Structure and Electrochemical Performance
N2 - An immobilization of graphene oxide (GO) into a matrix of polyvinyl formaldehyde (PVF) foam as an eco-friendly, low cost, superior, and easily recovered sorbent of Pb ions from an aqueous solution is described. The relationships between the structure and electrochemical properties of PVF/GO composite with implanted Pb ions are discussed for the first time. The number of alcohol groups decreased by 41% and 63% for PVF/GO and the PVF/GO/Pb composite, respectively, compared to pure PVF. This means that chemical bonds are formed between the Pb ions and the PVF/GO composite based on the OH groups. This bond formation causes an increase in the Tg values attributed to the formation of a strong surface complexation between adjacent layers of PVF/GO composite. The conductivity increases by about 2.8 orders of magnitude compared to the values of the PVF/GO/Pb composite compared to the PVF. This means the presence of Pb ions is the main factor for enhancing the conductivity where the conduction mechanism is changed from ionic for PVF to electronic conduction for PVF/GO and PVF/GO/Pb.
KW - Graphene oxide
KW - Polyvinyl formaldehyde
KW - Lead ions
KW - Conductivity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549588
DO - https://doi.org/10.3390/polym14112303
SN - 2073-4360
VL - 14
IS - 11
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-54958
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Gernhard, M.
A1 - Radnik, Jörg
A1 - Witt, Julia
A1 - Roth, C.
A1 - Emmerling, Franziska
T1 - Mechanochemical synthesis of fluorine-containing Co-doped zeolitic imidazolate frameworks for producing electrocatalysts
N2 - Catalysts derived from pyrolysis of metal organic frameworks (MOFs) are promising candidates to replace expensive and scarce platinum-based electrocatalysts commonly used in polymer electrolyte membrane fuel cells. MOFs contain ordered connections between metal centers and organic ligands. They can be pyrolyzed into metal- and nitrogen-doped carbons, which show electrocatalytic activity toward the oxygen reduction reaction (ORR). Furthermore, metal-free heteroatom-doped carbons, such as N-F-Cs, are known for being active as well. Thus, a carbon material with Co-N-F doping could possibly be even more promising as ORR electrocatalyst. Herein, we report the mechanochemical synthesis of two polymorphs of a zeolitic imidazole framework, Co-doped zinc 2-trifluoromethyl-1H-imidazolate (Zn0.9Co0.1(CF3-Im)2). Time-resolved in situ X-ray diffraction studies of the mechanochemical formation revealed a direct conversion of starting materials to the products. Both polymorphs of Zn0.9Co0.1(CF3-Im)2 were pyrolyzed, yielding Co-N-F containing carbons, which are active toward electrochemical ORR.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - Nobel-metal free electrocatalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546833
DO - https://doi.org/10.3389/fchem.2022.840758
SN - 2296-2646
VL - 10
IS - 840758
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-54683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolf, J.
A1 - Stawski, Tomasz
A1 - Smales, Glen Jacob
A1 - Thünemann, Andreas
A1 - Emmerling, Franziska
T1 - Towards automation of the polyol process for the synthesis of silver nanoparticles
N2 - Metal nanoparticles have a substantial impact across diferent felds of science, such as photochemistry, energy conversion, and medicine. Among the commonly used nanoparticles, silver nanoparticles are of special interest due to their antibacterial properties and applications in sensing and catalysis. However, many of the methods used to synthesize silver nanoparticles often do not result in well-defned products, the main obstacles being high polydispersity or a lack of particle size tunability. We describe an automated approach to on-demand synthesis of adjustable particles with mean radii of 3 and 5 nm using the polyol route. The polyol process is a promising route for silver nanoparticles e.g., to be used as reference materials. We characterised the as-synthesized nanoparticles using small-angle X-ray scattering, dynamic light scattering and further methods, showing that automated synthesis can yield colloids with reproducible and tuneable properties.
KW - Sillver
KW - Nanoparticles
KW - Automated synthesis
KW - Chemputer
KW - Scattering
KW - SAXS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546803
DO - https://doi.org/10.1038/s41598-022-09774-w
VL - 12
IS - 1
SP - 1
EP - 9
PB - Nature Springer
AN - OPUS4-54680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zänker, Steffen
A1 - Scholz, G.
A1 - Marquardt, Julien
A1 - Emmerling, Franziska
T1 - Structural changes in Ba-compounds of different hardness induced by high-energy ball milling – evidenced by 137Ba NMR and X-ray powder diffraction
N2 - Changes in the global bulk and local structures, of three different barium compounds (BaZrO3, BaF2, and BaFCl),were induced by mechanical milling and followed using X-ray powder diffraction (PXRD), subsequent microstructure analysis, and 137Ba solid state NMR spectroscopy. Harder materials like BaZrO3 experience significantly higher structural changes upon milling than softer materials like BaF2. Moreover, soft materials with layered structures, like BaFCl, show a pronounced structural change during the milling process. By combining PXRD and solid state NMR, detailed information on the changes to the global and local structures were obtained, which are of interest for mechanochemical synthesis, mechanically treated catalysts or ionic conductors.
KW - Mechanochemistry
KW - X-ray diffraction
KW - Solid state NMR
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547397
DO - https://doi.org/10.1002/zaac.202200026
SN - 0044-2313
VL - 648
IS - 10
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Belenguer, A.
A1 - Lampronti, G.
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
A1 - Sanders, J.
T1 - Quantitative reversible one pot interconversion of three crystalline polymorphs by ball mill grinding
N2 - We demonstrate here using a disulfide system the first example of reversible, selective, and quantitative transformation between three crystalline polymorphs by ball mill grinding. This includes the discovery of a previously unknown polymorph. Each polymorph is reproducibly obtained under well-defined neat or liquid-assisted grinding conditions, revealing subtle control over the apparent thermodynamic stability. We discovered that the presence of a contaminant as low as 1.5% mol mol−1 acting as a template is required to enable all these three polymorph transformations. The relative stabilities of the polymorphs are determined by the sizes of the nanocrystals produced under different conditions and by surface interactions with small amounts of added solvent. For the first time, we show evidence that each of the three polymorphs is obtained with a unique and reproducible crystalline size. This mechanochemical approach gives access to bulk quantities of metastable polymorphs that are inaccessible through recrystallisation.
KW - Mechanochemistry
KW - Polymorph
KW - XRD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549934
DO - https://doi.org/10.1039/D2CE00393G
SP - 1
EP - 7
PB - Royal Society of Chemistry
AN - OPUS4-54993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gugin, Nikita
A1 - Villajos Collado, José Antonio
A1 - Feldmann, Ines
A1 - Emmerling, Franziska
T1 - Mix and wait – a relaxed way for synthesizing ZIF-8
N2 - Herein we report the synthesis of a zeolitic imidazolate framework (ZIF-8) by an easy “mix and wait” procedure. In a closed vial, without any interference, the mixture of 2-methylimidazole and basic zinc carbonate assembles into the crystalline product with approx. 90% conversion after 70 h. The reaction exhibits sigmoidal kinetics due to the self-generated water which accelerates the reaction.
KW - In-situ analysis
KW - Mechanochemistry
KW - MOF
KW - Synthesis
KW - ZIF-8
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546841
DO - https://doi.org/10.1039/D2RA00740A
VL - 12
SP - 8940
EP - 8944
PB - Royal Society of Chemistry
AN - OPUS4-54684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
T1 - The Mechanochemical Excitation of Crystalline LiN3
N2 - Mechanochemical reactions are driven by the direct absorption of mechanical energy by a solid (often crystalline) material. Understanding how this energy is absorbed and ultimately causes a chemical transformation is essential for understanding the elementary stages of mechanochemical transformations. Using as a model system the energetic material LiN3 we here consider how vibrational energy flows through the crystal structure. By considering the compression response of the crystalline material we identify the partitioning of energy into an initial vibrational excitation. Subsequent energy flow is based on concepts of phonon–phonon scattering, which we calculate within a quasi-equilibrium model facilitated by phonon scattering data obtained from Density Functional Theory (DFT). Using this model we demonstrate how the moments (picoseconds) immediately following mechanical impact lead to significant thermal excitation of crystalline LiN3, sufficient to drive marked changes in its electronic structure and hence chemical reactivity. This work paves the way towards an ab initio approach to studying elementary processes in mechanochemical reactions involving crystalline solids.
KW - Energetic materials
KW - Ab initio simulation
KW - DFT
KW - Mechanochemistry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559310
DO - https://doi.org/10.1039/d2fd00112h
SP - 1
EP - 20
PB - Royal Society of Chemistry
AN - OPUS4-55931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Cakir, Cafer Tufan
A1 - Radtke, Martin
A1 - Haider, M. Bilal
A1 - Emmerling, Franziska
A1 - F. M. Oliveira, P.
A1 - Michalchuk, Adam
T1 - Dispersive x-ray absorption spectroscopy for time-resolved in situ monitoring of mechanochemical reactions
N2 - X-ray absorption spectroscopy (XAS) provides a unique, atom-specific tool to probe the electronic structure of solids. By surmounting long-held limitations of powder-based XAS using a dynamically averaged powder in a Resonant Acoustic Mixer (RAM), we demonstrate how time-resolved in situ (TRIS) XAS provides unprecedented detail of mechanochemical synthesis. The use of a custom-designed dispersive XAS (DXAS) setup allows us to increase the time resolution over existing fluorescence measurements from ∼15 min to 2 s for a complete absorption spectrum. Hence, we here establish TRIS-XAS as a viable method for studying mechanochemical reactions and sampling reaction kinetics. The generality of our approach is demonstrated through RAM-induced (i) bottom-up Au nanoparticle mechanosynthesis and (ii) the synthesis of a prototypical metal organic framework, ZIF-8. Moreover, we demonstrate that our approach also works with the addition of a stainless steel milling ball, opening the door to using TRIS-DXAS for following conventional ball milling reactions. We expect that our TRIS-DXAS approach will become an essential part of the mechanochemical tool box.
KW - In situ studies
KW - Dipsersive XAS
KW - Mechanochemistry
KW - Time-resolved
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567659
DO - https://doi.org/10.1063/5.0130673
SN - 1089-7690
VL - 157
IS - 21
SP - 1
EP - 12
PB - American Institute of Physics
CY - Melville, NY
AN - OPUS4-56765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mazzeo, P
A1 - Lampronti, G
A1 - Michalchuk, Adam
A1 - Belenguer, A
A1 - Bacchi, A
A1 - Emmerling, Franziska
T1 - Accurate extrinsic and intrinsic peak broadening modelling for time-resolved in situ ball milling reactions via synchrotron powder X-ray diffraction
N2 - The debate on the mechanisms which underpin mechanochemical reactions via ball mill grinding is still open. Our ability to accurately measure the microstructural (crystal size and microstrain) evolution of materials under milling conditions as well as their phase composition as a function of time is key to the in-depth understanding of the kinetics and driving forces of mechanochemical transformations. Furthermore, all ball milling reactions end with a steady state or milling equilibrium – represented by a specific phase composition and relative microstructure – that does not change as long as the milling conditions are maintained. The use of a standard sample is essential to determine the instrumental contribution to the X-ray powder diffraction (XRPD) peak broadening for time-resolved in situ (TRIS) monitoring of mechanochemical reactions under in operando conditions. Using TRIS-XRPD on a ball milling setup, coupled with low-energy synchrotron radiation, we investigated different data acquisition and analysis strategies on a silicon standard powder. The diffraction geometry and the microstructural evolution of the standard itself have been studied to model the instrumental contribution to XRPD peak broadening throughout the grinding activity. Previously proposed functions are here challenged and further developed. Importantly, we show that minor drifts of the jar position do not affect the instrumental resolution function significantly. We here report and discuss the results of such investigations and their application to TRIS-XRPD datasets of inorganic and organic ball mill grinding reactions.
KW - Mechanochemistry
KW - In situ diffraction
KW - Synchrotron radiation
KW - Sustainable chemisry
PY - 2022
DO - https://doi.org/10.1039/d2fd00104g
SP - 1
EP - 17
PB - Royal Society of Chemistry
AN - OPUS4-55932
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ravi, J.
A1 - Feiler, Torvid
A1 - Mondal, A.
A1 - Michalchuk, Adam
A1 - Reddy, C. M.
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Chandrasekar, R.
T1 - Plastically bendable organic crystals for monolithic and hybrid micro-optical circuits
N2 - Fluorescent plastically bendable crystals are a promising alternative to silicon-based materials for fabricating photonic integrated circuits, owing to their optical attributes and mechanical compliance. Mechanically bendable plastic organic crystals are rare. Their formation requires anisotropic intermolecular interactions and slip planes in the crystal lattice. This work presents three fluorescent plastically bendable crystalline materials namely, 2-((E)-(6-methylpyridin-2-ylimino)methyl)-4-chlorophenol (SB1), 2-((E)-(6-methylpyridin-2-ylimino)methyl)-4-bromophenol (SB2), and 2-((E)-(6-Bromopyridin-2-ylimino)methyl)-4-bromophenol (SB3) molecules. The crystal plasticity in response to mechanical stress facilitates the fabrication of various monolithic and hybrid (with a tip-to-tip coupling) photonic circuits using mechanical micromanipulation with an atomic force microscope cantilever tip. These plastically bendable crystals act as active (self-guiding of fluorescence) and passive waveguides both in straight and extremely bent (U-, J-, and O-shaped) geometries. These microcircuits use active and passive waveguiding principles and reabsorbance and energy-transfer mechanisms for their operation, allowing input-selective and direction-specific signal transduction.
KW - Flexible crystals
KW - Flexible waveguide
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565302
DO - https://doi.org/10.1002/adom.202201518
SN - 2195-1071
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56530
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Röder, Bettina
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - Controlling polymorphism in molecular cocrystals by variable temperature ball milling
N2 - Mechanochemistry offers a unique opportunity to modify and manipulate crystal forms, often providing new products as compared with conventional solution methods. While promising, there is little known about how to control the solid form through mechanochemical means, demanding dedicated investigations. Using a model organic cocrystal system (isonicotinamide:glutaric acid), we here demonstrate that with mechanochemistry, polymorphism can be induced in molecular solids under conditions seemingly different to their conventional thermodynamic (thermal) transition point. Whereas Form II converts to Form I upon heating to 363 K, the same transition can be initiated under ball milling conditions at markedly lower temperatures (348 K). Our results indicate that mechanochemical techniques can help to reduce the energy barriers to solid form transitions, offering new insights into controlling polymorphic forms. Moreover, our results suggest that the nature of mechanochemical transformations could make it difficult to interpret mechanochemical solid form landscapes using conventional equilibrium-based tools.
KW - Mechanochemistry
KW - Polymorphism
KW - TRIS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564728
DO - https://doi.org/10.1039/d2fd00115b
SP - 1
EP - 16
PB - Royal Society of Chemistry
AN - OPUS4-56472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lakshmipathi, M.
A1 - Dey, S.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
T1 - Designing Dual Mechanical Response in Molecular Crystals through Cocrystallization
N2 - Two isomorphous crystals are reported based on a naphthylvinylpyridine coformer. The crystals are mechanically flexible and exhibit photosalient response to UV irradiation. We therefore show how multiple mechanical phenomena can be simultaneously designed into a single material by cocrystallization.
KW - Cocrystal
KW - Mechanical response
PY - 2022
DO - https://doi.org/10.1021/acs.cgd.2c00913
SN - 1528-7483
VL - 22
SP - 6838
EP - 6843
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-56561
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - Unintended Rate Enhancement in Mechanochemical Kinetics by Using Poly(methyl methacrylate) Jars
N2 - Time-resolved in situ (TRIS) X-ray diffraction has changed how mechanochemical transformations are studied but requires the use of X-ray transparent jars often made from poly(methyl methacrylate) (PMMA). However, using PMMA jars can alter the apparent kinetics of mechanochemical polymorphism by an order of magnitude, questioning the interpretability of established TRIS methods. Our results suggest that rate enhancement in PMMA jars may not be dominated by chemical effects of the polymer, but rather a result of different equilibrium temperatures within the jar. These features must be better understood before control over mechanochemical reactions can be achieved.
KW - Mechanochemistry
KW - Organic compounds
KW - Polymers
KW - Materials
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565276
DO - https://doi.org/10.1021/acs.cgd.2c01227
SN - 1528-7483
SP - 1
EP - 5
PB - ACS Publications
AN - OPUS4-56527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völzke, Jule L.
A1 - Hodjat Shamami, Parya
A1 - Gawlitza, Kornelia
A1 - Feldmann, Ines
A1 - Zimathies, Annett
A1 - Meyer, Klas
A1 - Weller, Michael G.
T1 - High-purity corundum as support for affinity extractions from complex samples
N2 - Nonporous corundum powder, known as an abrasive material in the industry, was functionalized covalently with protein binders to isolate and enrich specific proteins from complex matrices. The materials based on corundum were characterized by TEM, ESEM, BET, DLS, EDS, and zeta potential measurements. The strong Al-O-P bonds between the corundum surface and amino phosphonic acids were used to introduce functional groups for further conjugations. The common crosslinker glutaraldehyde was compared with a hyperbranched polyglycerol (PG) of around 10 kDa. The latter was oxidized with periodate to generate aldehyde groups that can covalently react with the amines of the surface and the amino groups from the protein via a reductive amination process. The amount of bound protein was quantified via aromatic amino acid analysis (AAAA). This work shows that oxidized polyglycerol can be used as an alternative to glutaraldehyde. With polyglycerol, more of the model protein bovine serum albumin (BSA) could be attached to the surface under the same conditions, and lower non-specific binding (NSB) was observed. As a proof of concept, IgG was extracted with protein A from crude human plasma. The purity of the product was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A binding capacity of 1.8 mg IgG per gram of corundum powder was achieved. The advantages of corundum include the very low price, extremely high physical and chemical stability, pressure resistance, favorable binding kinetics, convenient handling, and flexible application.
KW - Corundum
KW - Sapphire
KW - Affinity chromatography
KW - Antibodies
KW - Self-assembled monolayers (SAM)
KW - Polyglycerol
KW - Dendrimer
KW - Nonspecific binding (NSB)
KW - Purification
KW - Solid-phase extraction (SPE)
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559342
DO - https://doi.org/10.3390/separations9090252
VL - 9
IS - 9
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-55934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazlagić, Anera
A1 - Russo, Francesco
A1 - Vogl, Jochen
A1 - Sturm, Patrick
A1 - Stephan, D.
A1 - Gluth, Gregor
ED - Resch-Genger, Ute
ED - Koch, Matthias
ED - Meermann, Björn
ED - Weller, Michael G.
T1 - Development of a sample preparation procedure for Sr isotope analysis of Portland cements
N2 - The 87Sr/86Sr isotope ratio can, in principle, be used for provenancing of cement. However, while commercial cements consist of multiple components, no detailed investigation into their individual 87Sr/86Sr isotope ratios or their influence on the integral 87Sr/86Sr isotope ratio of the resulting cement was conducted previously. Therefore, the present study aimed at determining and comparing the conventional 87Sr/86Sr isotope ratios of a diverse set of Portland cements and their corresponding Portland clinkers, the major component of these cements. Two approaches to remove the additives from the cements, i.e. to measure the conventional 87Sr/86Sr isotopic fingerprint of the clinker only, were tested, namely, treatment with a potassium hydroxide/sucrose solution and sieving on a 11-µm sieve. Dissolution in concentrated hydrochloric acid/nitric acid and in diluted nitric acid was employed to determine the 87Sr/86Sr isotope ratios of the cements and the individual clinkers. The aim was to find the most appropriate sample preparation procedure for cement provenancing, and the selection was realised by comparing the 87Sr/86Sr isotope ratios of differently treated cements with those of the corresponding clinkers. None of the methods to separate the clinkers from the cements proved to be satisfactory. However, it was found that the 87Sr/86Sr isotope ratios of clinker and cement generally corresponded, meaning that the latter can be used as a proxy for the clinker 87Sr/86Sr isotope ratio. Finally, the concentrated hydrochloric acid/nitric acid dissolution method was found to be the most suitable sample preparation method for the cements; it is thus recommended for 87Sr/86Sr isotope analyses for cement provenancing.
KW - Cement
KW - Provenancing
KW - Sr isotopes
KW - Portland clinker
KW - Dissolution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542239
DO - https://doi.org/10.1007/s00216-021-03821-7
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - 15 (Topical collection: Analytical methods and applications in the materials and life sciences)
SP - 4379
EP - 4389
PB - Springer
CY - Berlin
AN - OPUS4-54223
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Meermann, Björn
A1 - Koch, Matthias
A1 - Weller, Michael G.
T1 - Editorial: Analytical methods and applications in materials and life sciences
N2 - Current trends in materials and life sciences are flanked by the need to push detection limits to single molecules or single cells, enable the characterization of increasingly complex matrices or sophisticated nanostructures, speed up the time of analysis, reduce instrument complexity and costs, and improve the reliability of data. This requires suitable analytical tools such as spectroscopic, separation and imaging techniques, mass spectrometry, and hyphenated techniques as well as sensors and their adaptation to application-specific challenges in the environmental, food, consumer product, health sector, nanotechnology, and bioanalysis. Increasing concerns about health threatening known or emerging pollutants in drinking water, consumer products, and food and about the safety of nanomaterials led to a new awareness of the importance of analytical sciences. Another important driver in this direction is the increasing demand by legislation, particularly in view of the 17 sustainable development goals by the United Nations addressing clean energy, industry, and innovation, sustainable cities, clean water, and responsible consumption and production. In this respect, also the development of analytical methods that enable the characterization of material flows in production processes and support recycling concepts of precious raw materials becomes more and more relevant. In the future, this will provide the basis for greener production in the chemical industry utilizing recycled or sustainable starting materials.
This makes analytical chemistry an essential player in terms of the circular economy helping to increase the sustainability of production processes. In the life sciences sector, products based on proteins, such as therapeutic and diagnostic antibodies, increase in importance. These increasingly biotechnologically produced functional biomolecules pose a high level of complexity of matrix and structural features that can be met only by highly advanced methods for separation, characterization, and detection. In addition, metrological traceability and target definition are still significant challenges for the future, particularly in the life sciences.
However, innovative reference materials as required for the health and food sector and the characterization of advanced materials can only be developed when suitable analytical protocols are available. The so-called reproducibility crisis in sciences underlines the importance of improved measures of quality control for all kinds of measurements and material characterization. This calls for thorough method validation concepts, suitable reference materials, and regular interlaboratory comparisons of measurements as well as better training of scientists in analytical sciences.
The important contribution of analytical sciences to these developments is highlighted by a broad collection of research papers, trend articles, and critical reviews from these different application fields. Special emphasis is dedicated to often-overlooked quality assurance and reference materials.
T2 - 150 years BAM: Science with impact
CY - Berlin, Germany
DA - 01.01.2021
KW - Analysis
KW - Life sciences
KW - Analytical sciences
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Nanoparticle
KW - Sensor
KW - Material sciences
KW - Pollutant
KW - Environment
KW - Method
KW - Limit of detection
KW - 150th anniversary
KW - ABC
KW - BAM
KW - Collection
KW - Editorial
KW - Special issue
KW - Bundesanstalt für Materialforschung und -prüfung
KW - Jahrestag
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550720
DO - https://doi.org/10.1007/s00216-022-04082-8
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - Topical collection: Analytical methods and applications in the materials and life sciences
SP - 4267
EP - 4268
PB - Springer
CY - Berlin
AN - OPUS4-55072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kaufmann, Jan Ole
A1 - Brangsch, J.
A1 - Kader, A.
A1 - Saatz, Jessica
A1 - Mangarova, D. B.
A1 - Zacharias, M.
A1 - Kempf, W. E.
A1 - Schwaar, T.
A1 - Ponader, Marco
A1 - Adams, L. C.
A1 - Möckel, J.
A1 - Botnar, R. M.
A1 - Taupitz, M.
A1 - Mägdefessel, L.
A1 - Traub, Heike
A1 - Hamm, B.
A1 - Weller, Michael G.
A1 - Makowski, M. R.
T1 - ADAMTS4-specific MR-probe to assess aortic aneurysms in vivo using synthetic peptide libraries
N2 - The incidence of abdominal aortic aneurysms (AAAs) has substantially increased during the last 20 years and their rupture remains the third most common cause of sudden death in the cardiovascular field after myocardial infarction and stroke. The only established clinical parameter to assess AAAs is based on the aneurysm size. Novel biomarkers are needed to improve the assessment of the risk of rupture. ADAMTS4 (A Disintegrin And Metalloproteinase with ThromboSpondin motifs 4) is a strongly upregulated proteoglycan cleaving enzyme in the unstable course of AAAs. In the screening of a one-bead-one-compound library against ADAMTS4, a low-molecular-weight cyclic peptide is discovered with favorable properties for in vivo molecular magnetic resonance imaging applications. After identification and characterization, it’s potential is evaluated in an AAA mouse model. The ADAMTS4-specific probe enables the in vivo imaging-based prediction of aneurysm expansion and rupture.
KW - Peptide
KW - Peptide library
KW - OBOC library
KW - Combinatorial chemistry
KW - Peptide aptamers
KW - Binding molecule
KW - Affinity
KW - Synthetic peptides
KW - Contrast agent
KW - Magnetic resonance imaging
KW - One-bead-one-compound library
KW - On-chip screening
KW - Lab-on-a-chip
KW - MALDI-TOF MS
KW - SPR
KW - Surface plasmon resonance
KW - Alanine scan
KW - Fluorescence label
KW - MST
KW - Docking
KW - Chelate
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560930
DO - https://doi.org/10.1038/s41467-022-30464-8
N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M.
VL - 13
IS - 1
SP - 1
EP - 18
PB - Springer Nature Limited
CY - Heidelberg
AN - OPUS4-56093
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völzke, Jule L.
T1 - Corundum as a novel affinity platform for the isolation of human IgG from plasma
N2 - Nonporous corundum powder was functionalized covalently with protein binders to isolate and enrich specific proteins from complex matrices.The common crosslinker glutaraldehyde was compared with a hyperbranched polyglycerol (PG) of around 10 kDa. The latter was oxidized with periodate to generate aldehyde groups that can covalently react with the amines of the surface and the amino groups from the protein via a reductive amination process. The amount of bound protein was quantified via aromatic amino acid analysis (AAAA). As a proof of concept, IgG was extracted with protein A from crude human plasma. The advantages of corundum include the very low price, extremely high physical and chemical stability, pressure resistance, favorable binding kinetics, convenient handling, and flexible application.
T2 - Adlershofer Forschungsforum 2022
CY - Berlin, Germany
DA - 11.11.2022
KW - Affinity support
KW - Affinity chromatography
KW - Affinity extraction
KW - Phosphonic acids
KW - Polyglycerol
KW - Reductive amination
KW - Amino acid analysis
KW - Tyrosine
KW - Protein quantification
KW - SDS-PAGE
KW - Antibodies
KW - Antibody purification
KW - Downstream processing
KW - Bovine serum albumin
KW - BSA
KW - Protein a
KW - TEM
KW - ESEM
KW - Aluminum oxide
KW - Sapphire
KW - Human plasma
KW - Protein immobilization
KW - Protein hydrolysis
KW - Glutaraldehyde
KW - Aromatic amino acid analysis AAAA
PY - 2022
AN - OPUS4-56154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Völzke, Jule L.
A1 - Hodjat Shamami, Parya
A1 - Gawlitza, Kornelia
A1 - Feldmann, Ines
A1 - Zimathies, Annett
A1 - Weller, Michael G.
T1 - High-purity corundum as support for affinity extractions from complex samples
N2 - Nonporous corundum powder, known as an abrasive material in the industry, was functionalized covalently with protein binders to isolate and enrich specific proteins from complex matrices. The materials based on corundum were characterized by TEM, ESEM, BET, DLS, and zeta potential measurements. The strong Al-O-P bonds between the corundum surface and amino phosphonic acids are used to introduce functional groups for further conjugations. The common cross-linker glutaraldehyde was compared with a hyperbranched polyglycerol (PG) of around 10 kDa. The latter is oxidized with periodate to generate aldehyde groups that can covalently react with the amines of the surface and the amino groups from the protein via a reductive amination process. The amount of bound protein was quantified via aromatic amino acid analysis (AAAA). This work shows that oxidized polyglycerol can be used as an alternative to glutaraldehyde. With polyglycerol, more of the model protein bovine serum albumin (BSA) could be attached to the surface under the same conditions, and lower nonspecific binding (NSB) was observed. As a proof of concept, IgG was extracted with protein A from crude human plasma. The purity of the product was examined by SDS-PAGE. A binding capacity of 1.8 mg IgG per g of corundum powder was achieved. The advantages of corundum are the very low price, extremely high physical and chemical stability, pressure resistance, favorable binding kinetics, and flexible application.
KW - Protein
KW - Bioseparation
KW - Purification
KW - Immunoprecipitation
KW - Affinity chromatography
KW - Polyglycerol
KW - Glutaraldehyde
KW - Linker
KW - Bioconjugation
KW - Self-assembled monolayer (SAM)
KW - Periodate oxidation
KW - Reductive amination
KW - Antibodies
KW - Igg
KW - Immunoglobulins
KW - Carrier
KW - Solid phase
KW - Hyperbranched polymer
KW - Aromatic amino acid analysis aaaa
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555142
DO - https://doi.org/10.20944/preprints202208.0004.v1
SN - 2310-287X
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-55514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Röder, Bettina
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - Controlling polymorphism in molecular cocrystals by variable temperature ball milling
N2 - Mechanochemistry offers a unique opportunity to modify and manipulate crystal forms, often providing new products as compared with conventional solution methods. While promising, there is little known about how to control the solid form through mechanochemical means, demanding dedicated investigations. Using a model organic cocrystal system (isonicotinamide:glutaric acid), we here demonstrate that with mechanochemistry, polymorphism can be induced in molecular solids under conditions seemingly different to their conventional thermodynamic (thermal) transition point.
Whereas Form II converts to Form I upon heating to 363 K, the same transition can be initiated under ball milling conditions at markedly lower temperatures (348 K). Our results indicate that mechanochemical techniques can help to reduce the energy barriers to solid form transitions, offering new insights into controlling polymorphic forms. Moreover, our results suggest that the nature of mechanochemical transformations could make it difficult to interpret mechanochemical solid form landscapes using conventional equilibrium-based tools.
KW - Mechanochemistry
KW - Kinetics
KW - In situ
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558878
DO - https://doi.org/10.1039/d2fd00115b
SP - 1
EP - 16
PB - Royal Society of Chemistry
AN - OPUS4-55887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heilmann, Maria
A1 - Prinz, Carsten
A1 - Bienert, Ralf
A1 - Wendt, R.
A1 - Kunkel, B.
A1 - Radnik, Jörg
A1 - Hoell, A.
A1 - Wohlrab, S.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
T1 - Size-Tunable Ni–Cu Core–Shell Nanoparticles—Structure, Composition, and Catalytic Activity for the Reverse Water–Gas Shift Reaction
N2 - A facile and efficient methodology is described for the solvothermal synthesis of size-tunable, stable, and uniform NiCu core–shell nanoparticles (NPs) for application in catalysis. The diameter of the NPs is tuned in a range from 6 nm to 30 nm and to adjust the Ni:Cu ratio from 30:1 to 1:1. Furthermore, the influence of different reaction parameters on the final NPs is studied. The NPs are structurally characterized by a method combination of transmission electron microscopy, anomalous small-angle X-ray scattering, X-ray absorption fine structure, and X-ray photoelectron spectroscopy. Using these analytical methods, it is possible to elucidate a core–shell–shell structure of all particles and their chemical composition. In all cases, a depletion from the core to the shell is observed, with the core consisting of NiCu alloy, surrounded by an inner Ni-rich shell and an outer NiO shell. The SiO2-supported NiCu core–shell NPs show pronounced selectivity of >99% for CO in the catalytic reduction of CO2 to CO using hydrogen as reactant (reverse water–gas shift reaction) independent of size and Ni:Cu ratio.
KW - Nanoparticles
KW - Core-shell
KW - Catalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543606
DO - https://doi.org/10.1002/adem.202101308
SN - 1438-1656
SP - 1
EP - 13
PB - Wiley VCH
AN - OPUS4-54360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Axel
A1 - Altmann, Korinna
A1 - Kocher, B.
A1 - Braun, U.
T1 - Determination of tire wear markers in soil samples and their distribution in a roadside soil
N2 - Tire wear (TW) constitutes a significant source of microplastic in terrestrial ecosystems. It is known that particles emitted by roads can have an effect up to 100 m into adjacent areas. Here, we apply for the first-time thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS) to determine TW in soil samples by detection of thermal decomposition products of styrene-butadiene rubber (SBR), without additional enrichment. Additionally, zinc contents were determined as an elemental marker for TW. Mixed soil samples were taken along three transects along a German motorway in 0.3, 2.0, and 5.0 m distance from the road. Sampling depths were 0–2, 2–5, 5–10, and 10–20 cm. Four fine fractions, 1 000–500, 500–100, 100–50, and <50 μm, were analyzed.
TW contents based on SBR ranged from 155 to 15 898 mg kg−1. TW contents based on zinc were between 413 and 44 812 mg kg−1. Comparison of individual values of SBR and zinc reveals SBR as a more specific marker. Results confirm that most TW ends up in the topsoil within a 2 m distance.
The sampling strategy resulted in representative data for a larger area. Standard deviations of quadruple TED-GC/MS determination of SBR were <10% for all grain size fractions. TED-GC/MS is a suitable analytical tool for determining TW in soil samples without the use of toxic chemicals, enrichment, or special sample preparation.
KW - Microplastic
KW - TED-GC/MS
KW - Tire wear
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543344
DO - https://doi.org/10.1016/j.chemosphere.2022.133653
VL - 294
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-54334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Loges, A.
A1 - Scholz, G.
A1 - de Sousa Amadeu, Nader
A1 - Jingjing, S.
A1 - Emmerling, Franziska
A1 - John, T.
A1 - Paulus, B.
A1 - Braun, T.
T1 - Studies on the local structure of the F/OH site in topaz by magic angle spinning nuclear magnetic resonance and Raman spectroscopy
N2 - he mutual influence of F and OH groups in neighboring sites in topaz (Al2SiO4(F,OH)2) was investigated using magic angle spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The splitting of 19F and 1H NMR signals, as well as the OH Raman band, provides evidence for hydrogen bond formation within the crystal structure. Depending on whether a given OH group has another OH group or fluoride as its neighbor, two different hydrogen bond constellations may form: either OH···O···HO or F···H···O. The proton accepting oxygen was determined to be part of the SiO4 tetrahedron using 29Si MAS NMR. Comparison of the MAS NMR data between an OH-bearing and an OH-free topaz sample confirms that the 19F signal at −130 ppm stems from F− ions that take part in H···F bonds with a distance of ∼ 2.4 Å, whereas the main signal at −135 ppm belongs to fluoride ions with no immediate OH group neighbors. The Raman OH sub-band at 3644 cm−1 stems from OH groups neighboring other OH groups, whereas the sub-band at 3650 cm−1 stems from OH groups with fluoride neighbors, which are affected by H···F bridging. The integrated intensities of these two sub-bands do not conform to the expected ratios based on probabilistic calculations from the total OH concentration. This can be explained by a difference in the polarizability of the OH bond between the different hydrogen bond constellations or partial order or unmixing of F and OH, or a combination of both. This has implications for the quantitative interpretation of Raman data on OH bonds in general and their potential use as a probe for structural (dis-)order. No indication of tetrahedrally coordinated Al was found with 27Al MAS NMR, suggesting that the investigated samples likely have nearly ideal Al/Si ratios, making them potentially useful as high-density electron microprobe reference materials for Al and Si, as well as for F.
KW - Topas
KW - NMR
KW - XRD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561863
DO - https://doi.org/10.5194/ejm-34-507-2022
SN - 1617-4011
VL - 34
IS - 5
SP - 507
EP - 521
PB - Copernicus Publications
CY - Göttingen
AN - OPUS4-56186
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mazzeo, P. P.
A1 - Prencipe, M.
A1 - Feiler, Torvid
A1 - Emmerling, Franziska
A1 - Bacchi, A.
T1 - On the mechanism of cocrystal mechanochemical reaction via low melting eutectic: A time-resolved in situ monitoring investigation
N2 - Mechanochemistry has become a sustainable and attractive cost-effective synthetic technique, largely used within the frame of crystal engineering. Cocrystals, namely, crystalline compounds made of different chemical entities within the same crystal structure, are typically synthesized in bulk via mechanochemistry; however, whereas the macroscopic aspects of grinding are becoming clear, the fundamental principles that underlie mechanochemical cocrystallization at the microscopic level remain poorly understood. Time-resolved in situ (TRIS) monitoring approaches have opened the door to exceptional detail regarding mechanochemical reactions. We here report a clear example of cocrystallization between two solid coformers that proceeds through the formation of a metastable low melting binary eutectic phase. The overall cocrystallization process has been monitored by time-resolved in situ (TRIS) synchrotron X-ray powder diffraction with a customized ball milling setup, currently available at μ Spot beamline at BESSY-II, Helmholtz-Zentrum Berlin. The binary system and the low melting eutectic phase were further characterized via DSC, HSM, and VT-XRPD.
KW - Mechanochemistry
KW - In situ
KW - Cocrystal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552977
DO - https://doi.org/10.1021/acs.cgd.2c00262
SN - 1528-7505
VL - 22
IS - 7
SP - 4260
EP - 4267
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-55297
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pakrashy, S.
A1 - Mandal, P. K.
A1 - Goswami, J. N.
A1 - Dey, S. K.
A1 - Choudhury, S. M.
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Alasmary, F. A.
A1 - Dolai, M.
T1 - Bioinformatics and Network Pharmacology of the First Crystal Structured Clerodin: Anticancer and Antioxidant Potential against Human Breast Carcinoma Cell
N2 - Clerodin was isolated from the medicinal plant Clerodendrum infortunatum, and CSD search showed the first crystal structure of clerodin by a single-crystal X-ray diffraction study. We checked its binding potential with target proteins by docking and conducted network pharmacology analysis, ADMET analysis, in silico pathway analysis, normal mode analysis (NMA), and cytotoxic activity studies to evaluate clerodin as a potential anticancer agent. The cell viability studies of clerodin on the human breast carcinoma cell line (MCF-7) showed toxicity on MCF-7 cells but no toxicity toward normal human lymphocyte cells (HLCs). The anticancer mechanism of clerodin was validated by its enhanced capacity to produce intracellular reactive oxygen species (ROS) and to lower the reduced glutathione content in MCF-7 cells.
KW - Anticancer
KW - Clerodin
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567600
DO - https://doi.org/10.1021/acsomega.2c07173
SN - 2470-1343
VL - 7
IS - 51
SP - 48572
EP - 48582
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-56760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Bhattacharya, Biswajit
A1 - Witt, Julia
A1 - Jain, Mohit
A1 - Emmerling, Franziska
T1 - In situ time-resolved monitoring of mixed-ligand metal–organic framework mechanosynthesis
N2 - The mechanism of mixed-ligand metal–organic framework (MOF) formation, and the possible role of intermediate single-ligand metal complexes during mechanosynthesis, have not been explored yet. For the first time, we report here in situ real-time monitoring of the mechanochemical formation mechanism of mixed-ligand MOFs. Our results show that binary phases can act as intermediates or competing products in one-pot and stepwise synthesis.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - In situ X-ray diffraction
KW - Mixed-ligand MOFs
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558167
DO - https://doi.org/10.1039/D2CE00803C
SP - 1
EP - 4
PB - Royal Society of Chemistry
AN - OPUS4-55816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emmerling, Franziska
A1 - Hoch, C.
T1 - Laudatio Prof. Dr.-Ing. Caroline Röhr
N2 - It is a laudatio on the ocations of Prof. Dr.-Ing. Caroline Röhrs 60th birthday.
KW - Metal-oxides
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561877
DO - https://doi.org/10.1002/zaac.202200159
SN - 0044-2313
VL - 648
IS - 10
SP - 1
EP - 2
PB - John Wiley & Sons, Ltd
AN - OPUS4-56187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Kochovski, Z.
A1 - Feldmann, Ines
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz
T1 - Ni- and Co-Struvites: Revealing Crystallization Mechanisms and Crystal Engineering toward Applicational Use of Transition Metal Phosphates
N2 - Industrial and agricultural waste streams (waste water, sludges, tailings, etc.) which contain high concentrations of NH4+, PO43–, and transition metals are environmentally harmful and toxic pollutants. At the same time, phosphorous and transition metals constitute highly valuable resources. Typically, separate pathways have been considered to extract hazardous transition metals or phosphate independently from each other. Investigations on the simultaneous removal of multiple components have been carried out only to a limited extent. Here, we report the synthesis routes for Ni- and Co-struvites (NH4MPO4·6H2O, M = Ni2+ and Co2+), which allow for P, ammonia, and metal co-precipitation. By evaluating different reaction parameters, the phase and stability of transition metal struvites as well as their crystal morphologies and sizes could be optimized. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P) ratios, whereas Co-struvite only forms at low M/P ratios. Detailed investigations of the precipitation process using ex situ and in situ techniques provided insights into the crystallization mechanisms/crystal engineering of these materials. M-struvites crystallize via intermediate colloidal amorphous nanophases, which subsequently aggregate and condense to final crystals after extended reaction times. However, the exact reaction kinetics of the formation of a final crystalline product varies significantly depending on the involved metal cation in the precipitation process: several seconds (Mg) to minutes (Ni) to hours (Co). The achieved level of control over the morphology and size makes precipitation of transition metal struvites a promising method for direct metal recovery and binding them in the form of valuable phosphate raw materials. Under this paradigm, the crystals can be potentially up-cycled as precursor powders for electrochemical or (electro)catalytic applications, which require transition metal phosphates.
KW - Crystallization
KW - Struvite
KW - Nickel
KW - Cobalt
KW - Phosphorous recovery
KW - Up-cycling
KW - Aqueous synthesis
PY - 2022
DO - https://doi.org/10.1021/acs.cgd.2c00284
VL - 22
IS - 7
SP - 4305
EP - 4315
PB - ACS Publications
CY - Washington D.C.
AN - OPUS4-55286
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
T1 - Time-Resolved InSitu Monitoring of Mechanochemical Reactions
N2 - Mechanochemical transformations offer environmentally benign synthesis routes, whilst enhancing both the speed and selec-tivity of reactions. In this light, mechanochemistry promises to trans-form the way in which chemistry is done in both academia and indus-try but is greatly hindered by a current lack in mechanistic understand-ing. The continued development and use of time-resolved in situ(TRIS) approaches to monitor mechanochemical reactions provides a new dimension to elucidatethese fascinating transformations. We here discuss recent trends in method development that have pushed the boundaries of mechanochemical research. New features of mech-anochemical reactions obtained by TRIS techniques are subse-quently discussed, shedding light on how different TRISapproaches have beenused. Emphasis is placed on the strength of combining complementary techniques. Finally, we outline our views for the po-tential of TRIS methods in mechanochemical research, towards es-tablishing a new, environmentally benign paradigm in the chemical sciences
KW - Mechanochemistry
KW - Material synthesis
KW - Green chemistry
PY - 2022
DO - https://doi.org/10.1002/anie.202117270
SN - 1433-7851
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54321
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wegner, Karl David
A1 - Häusler, I.
A1 - Knigge, Xenia
A1 - Hodoroaba, Vasile-Dan
A1 - Emmerling, Franziska
A1 - Reiss, P.
A1 - Resch-Genger, Ute
T1 - One-Pot Heat-Up Synthesis of ZnSe Magic-Sized Clusters Using Thiol Ligands
N2 - The synthesis of two new families of ZnSe magic-sized clusters (MSCs) is achieved using the thiol ligand 1-dodecanethiol in a simple one-pot heat-up approach. The sizes of the MSCs are controlled with the thiol ligand concentration and reaction temperature.
KW - ZnSe
KW - Magic-sized cluster
KW - Dodecanethiol
KW - Semiconductor nanocrystals
KW - One-pot synthesis
PY - 2022
DO - https://doi.org/10.1021/acs.inorgchem.2c00041
VL - 61
IS - 19
SP - 7207
EP - 7211
PB - ACS Publications
CY - Washington, DC (USA)
AN - OPUS4-54880
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, A.
A1 - Saeed, A.
A1 - Dawood, U.
A1 - Abdelbary, H.
A1 - Altmann, Korinna
A1 - Schönhals, Andreas
T1 - Nano-MnO2/xanthan gum composite films for NO2 gas sensing
N2 - Nowadays, sensors based on polymers/nanostructured metal oxide composites have been investigated exten-sively because of their sensitivity to NO2 gas at ambient temperature. In this work, nanocomposite membranes of xanthan gum (XG) with different contents of MnO2 nanoparticles were prepared as a potential NO2 gas sensor operating at room temperature by a simple one-step oxidation-reduction reaction. The structural, morphological, thermal, and electrical properties of the composite membrane were investigated. The FT-IR results confirm the successful preparation of MnO2 through the oxidation of XG by KMnO4 and reveal further the structural changes of the XG/MnO2 nanocomposite upon its exposure to NO2 gas. The capping of the synthesized MnO2 nano-particles by XG, the surface composition of the XG/MnO2 nanocomposite membranes, and the effect of NO2 gas on the surface composition was investigated using the XPS technique. The DC conductivity and dielectric loss of nanocomposites were higher than for neat XG. The conductivities of the nanocomposites XG/MO-4, XG/MO-4/ low NO2, and XG/MO-4/high NO2 composites are half, one, and three orders of magnitude higher than that for pure XG revealing a transition from insulating to conductive properties. The results demonstrated that XG/MnO2 nanocomposite membranes are promising for potential applications in NO2 gas sensing.
KW - Gas sensors
KW - Membranes
KW - Metal oxides
KW - Nanocomposites
KW - Semiconductors
PY - 2022
DO - https://doi.org/10.1016/j.matchemphys.2022.127277
SN - 0254-0584
VL - 296
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-56769
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lakshmipathi, M.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Structure-mechanical property correlation of a series of 4-(1-Napthylvinyl) pyridine based cocrystals
N2 - We obtained three 4-(1-Napthylvinyl) pyridine based cocrystals ( 1–3 ) and studied its structure mechan- ical property correlation which aimed towards various applications for photo switches, mechanical ac- tuators etc. Selection of coformer molecules is important in fine tuning mechanical property outcome of synthesized cocrystals. Amongst three cocrystals, cocrystal 1 is mechanically flexible and its mechani- cal property is attributed to underlying crystal packing features which is in line with existing elastically bendable crystals while other two cocrystals ( 2, 3 ) are brittle in nature. Hirshfeld analysis was carried out to illustrate structure-property correlation particularly in terms of number as well as types of non- covalent interactions in the lattice and further to corroborate the space of the molecules in the lattice.
KW - Cocrystals
KW - Mechanical properties
KW - Halogen bond interaction
KW - Structure-mechanical property correlation
PY - 2022
DO - https://doi.org/10.1016/j.molstruc.2022.133670
SN - 0022-2860
VL - 1268
SP - 1
EP - 16
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55547
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waniek, Tassilo
T1 - The practical implementation of MP reference material production according to ISO standards
N2 - Micro- and nanoplastic particles became a topic of public concern all over the world e.g. in water, soil, sludge and air. For a profound risk assessment, it is necessary to identify the origins, hotspots, or transport between different media. Therefore, a representative repeatable analysis is required and reference materials (RM) to proof and compare methods.
The basis of MNP investigations is a harmonized analysis which includes sampling, sample preparation and detection. In recent years, spectroscopic methods like µRaman and µFTIR for the determination of particle numbers or thermoanalytical methods like Pyrolysis gas chromatography/mass spectrometry (py-GC/MS) and Thermo extraction/ desorption gas chromatography / mass spectrometry (TED-GC/MS) for mass determination have proven to be particularly suitable.
The technical committees (TC) of ISO TC 61 “plastics” and TC 147 “water quality" are working on harmonisation processes on international level. For all standardization approaches, it is necessary that the detection methods and analysis processes can be validated. Therefore, BAM develops reference material for microplastic (MP) analysis for several years with focus on the most common polymers PE, PP, PS, PET and PA.
MP particles with a close to reality fragment shape are obtained by cryomilling and sieving. For sample preparation purposes with mass detection methods MP particles are pressed into pills with a water-soluble matrix. Thereby losses due to sample preparation e.g. filtration are included in the verification of an analysis.
To ensure a constant quality throughout all MP RM batches the homogeneity and stability is controlled according to ISO Guide 35. Next to TED-GC/MS measurements particle size distribution, infrared spectroscopy and differential scanning calorimetry spectra are taken as accompanying parameters.
This presentation aims to introduce into the MP RM production process with ensured quality and special focus on pointing out customized setups for particle comminution, separation, and characterization for standardization.
T2 - ASTM Syposioum on Microplastic Analytical and Reference Standards - Opportunities to Advance Microplastic Science
CY - Seattle, WA, USA
DA - 30.06.2022
KW - Microplastic
KW - Reference material
KW - Cryo milling
KW - Polymer
PY - 2022
AN - OPUS4-55891
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Cocrystal polymorphs & Mechanochemistry - Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new crystal forms. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity. Control over ball milling transformations is needed before the transformative potential of mechanochemical processing can be realized. Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography. Here we will discuss our recent results investigating the formation of polymorphic cocrystals thereby elucidating the influence of milling parameters (solvent, temperature, time) and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 33th European Crrystallography Meeting
CY - Versailles, France
DA - 23.08.2022
KW - Mechanochemistry
KW - Cocrystals
KW - Kinetics
KW - Polymorphs
PY - 2022
AN - OPUS4-55586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Braun, U.
T1 - Detection of plastics in soil
N2 - Soil acts as a final sink for pollutants. Microplastics from different sources such as plastic mulching, littering, compost, sewage sludge, sedimentary deposition, and tyre abrasion are expected to be found in soil. However, representative and comprehensive information is missing on the sources, transport, and fate. Therefore, a reliable analysis method for microplastics in soils needs to be developed.
The presented work describes the development of a procedure for microplastics analysis in soils. A representative sampling based on the on-site conditions and a sample preparation method was established and comprised of a drying step, the separation of microplastic particles > 1 mm, and a density separation for particles < 1 mm. The detection of the large microplastic particles (> 1 mm) was conducted with Attenuated Total Reflection - Fourier Transform infrared Spectroscopy (ATR-FTIR) , while Thermal Extraction Desorption - Gas Chromatography / Mass Spectrometry (TED-GC/MS) was applied for particles < 1 mm, gaining information on the type of polymer and mass fraction. Based on the established method, 14 environmental soil samples ? with different exposure of microplastics from agriculture, industrial sites, roads, and floods were investigated.
Due to the arbitrary microplastic particle distribution among the samples for large microplastics, it was reasoned that the found particles were unrepresentative. In contrast, microplastic particles < 1 mm were discovered in a high mass in soil samples exposed to plastic mulching or fertilization with sewage sludge or compost (0 – 115 mg/kg). On average, microplastic contents detected in soil samples taken from a construction site and an inner-city lake were higher (13 – 238 mg/kg). As expected, microplastic content in soil sampled in proximity to roads was more pronounced in the upper soil layers. In contrast, very remote sampling sites, expectably uncontaminated, did not lead to the detection of microplastic regarding to thermoanalytical detection method.
In a proof of concept experiment several in vivo and in vitro ecotoxicological tests were applied to evaluate the effect of microplastics (tyre abrasion, polystyrene containing hexabromocyclododecane) in natural soils. In summary, while no effects of the examined probes could be detected on higher levels of biological organization after exposures to earthworm E. andrei, significant changes in several oxidative stress related biomarkers were observed.
T2 - SETAC Europe 2022
CY - Kopenhagen, Denmark
DA - 15.05.2022
KW - Microplastic
KW - TED-GC/MS
KW - Soil
PY - 2022
AN - OPUS4-55872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Cocrystal polymorphs & Mechanochemistry - Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new crystal forms. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity. Control over ball milling transformations is needed before the transformative potential of mechanochemical processing can be realized. Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography. Here we will discuss our recent results investigating the formation of polymorphic cocrystals thereby elucidating the influence of milling parameters (solvent, temperature, time) and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 3rd CEFMC meeting
CY - Kashmir, India
DA - 31.08.2022
KW - Mechanochemistry
KW - Crystal Engeneering
PY - 2022
AN - OPUS4-55641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -