TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Sahre, Mario
A1 - Corrao, Elena
A1 - Pellegrino, Francesco
A1 - Alonso, Beatriz
A1 - Zurutuza, Amaia
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Standardized Elemental Composition Analysis of Graphene‐Related 2D Materials (GR2M) With SEM/EDS and XPS Works Reliably
N2 - Reliable quantification of the chemical composition of graphene‐related 2D materials (GR2M) as powders and liquid suspensions is a challenging task. Analytical methods such as X‐ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP‐MS), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) are recommended by standardization bodies. The specific parameters to be measured are also defined, e.g., the oxygen‐to‐carbon (O/C) atomic ratio, the trace metal impurities, or the functional groups. In this contribution, for the first time, results of a systematic study on the capability of energy‐dispersive X‐ray spectroscopy (EDS) at a scanning electron microscope (SEM) to reliably quantify the O/C ratio and impurities remained from the synthesis of selected GR2M are reported. The robustness of SEM/EDS analysis is verified for various measurement conditions (different excitations and EDS detectors) and the validity of the results is tested by comparison to the established XPS analysis. Moreover, an ionic liquid is used as a reference material for the quantification of the light elements such as C, N, O and F. The study clearly demonstrates the reliability of the fast and widely available SEM/EDS as a standard method for the quantification of the elemental composition of GR2M and generally of light materials.
KW - Graphene oxide flakes
KW - Impurities
KW - O/C ratio
KW - SEM/EDS
KW - Standard
KW - XPS
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656748
DO - https://doi.org/10.1002/smll.202511283
SN - 1613-6810
SP - 1
EP - 10
PB - Wiley-VHC GmbH
AN - OPUS4-65674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aliyah, K.
A1 - Berger, A.
A1 - Lazaridis, T.
A1 - Appel, C.
A1 - Prehal, C.
A1 - Menzel, A.
A1 - Guizar-Sicairos, M.
A1 - Smales, Glen J.
A1 - Pauw, Brian Richard
A1 - Gasteiger, H. A.
A1 - Gubler, L.
A1 - Büchi, F. N.
A1 - Eller, J.
T1 - Impact of Microporous Layer Composition on the Water Content in the Membrane Electrode Assembly of Polymer Electrolyte Fuel Cells
N2 - Polymer electrolyte fuel cells are paramount for future emission-free mobility. One of the vital challenges for prospering commercialization of PEFCs is water management in the cells. A microporous layer (MPL) is typically positioned between the gas Diffusion layer (GDL) and the catalyst layer (CL) to boost the cell performance and facilitate water management. In this study, three different MPLs were investigated, namely, carbon black-based MPLs with different PTFE binder contents (20 wt % PTFE as a base case and 40 wt % PTFE), as well as perforated MPLs with micron-sized pores coated on the same GDL- Substrate (Freudenberg H14). The water content in the membrane, catalyst layers (CL), and MPLs was explored using operando scanning small- and wide-angle X-ray scattering (S/WAXS). At Tcell = 80 °C, relative humidity = 100%, pabs = 3 bar, the MPL with larger pores exhibits slightly higher performance than the base case, while a considerably lower cathode CL and MPL saturation levels were observed for the MPL. In contrast, the MPL with higher amounts of PTFE binder shows lower performance than the base case, with considerably higher cathode CL and MPL saturation levels. 3D representations of how the pores could be filled in the cathode CLs were obtained from operando SAXS profiles using representative structure modeling for the different materials and operating conditions.
KW - Polymer electrolyte fuel cell
KW - Catalyst layer saturation
KW - Microporous layer saturation
KW - Membrane hydration
KW - Small and wide-angle scattering
KW - MOUSE
KW - SAXS
KW - X-ray scattering
KW - Energy storage materials
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656691
DO - https://doi.org/10.1021/acsami.5c22540
SN - 1944-8244
SP - 1
EP - 17
PB - American Chemical Society (ACS)
AN - OPUS4-65669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Charlesworth, M.
A1 - Lampronti, G.
A1 - Belenguer, Ana M.
A1 - Day, S.
A1 - Saunders, L.
A1 - Connolly, E.
A1 - Midgley, P.
A1 - Michalchuk, Adam A. L.
T1 - Influence of Liquid on Crystallite Size Evolution During Ball Milling
N2 - Liquid assisted grinding (LAG) is a commonly used mechanochemical procedure, especially for polymorphic conversions. However, it is not understood what effect liquid additives actually play in driving mechanochemical polymorphic conversions, precluding our ability to control solid form transformations under mechanochemical conditions. We here present a time-resolved in situ (TRIS) synchrotron powder Xray diffraction (PXRD) monitoring strategy that can track, with few nm resolution, the evolution of crystalline size under liquid assisted ball milling conditions. We apply this method to investigate the influence of liquid additives on the polymorphic conversion of the 1:1 co-crystal of theophylline and benzamide, with particular focus on the role that crystallite size plays in driving ball milling induced polymorphic transformations. We find that the crystallite sizes achieved by ball milling are highly sensitive to the amount of liquid added to the reaction mixture. Liquid additives generally lead to larger crystallite sizes as compared with neat grinding protocol, with our findings indicating that crystallite size reduction is not the main factor that causes polymorph conversion under liquid assisted grinding conditions. The data presented clearly indicates the presence of an induction period before phase transformation begins with a minimum value in the crystallite size of the starting polymorph indicating the end of that induction period.
KW - Ball milling
KW - In situ diffraction
KW - Phase transformation
KW - Liquid assisted grinding
KW - Crystallite size
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656783
DO - https://doi.org/10.1021/acs.cgd.5c01662
SN - 1528-7483
SP - 1
EP - 7
PB - American Chemical Society (ACS)
AN - OPUS4-65678
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Phase-field simulation of the dendrite fragmentation by electromagnetic stirring in AA5754 aluminum alloy laser beam welding
N2 - A phase-field model including magnetic field induced dendrite fragmentation was established and applied to the cases with different initial crystal nuclear positions for AA5754 aluminum alloy electromagnetic laser beam welding. Compare the calculated results that include dendrite fragmentation caused by the thermal electromagnetic Lorentz force with the results that consider only the thermal electromagnetic Lorentz force, without fragmentation, at the characteristic time instants. Both in the early and late stages, the small fragmentation at the dendrite tip promotes the number of higher-order branches and their growth, especially in the direction perpendicular to the solidification. The later stage fragmentation has the possibility of breaking one grain into several, which verifies the possibility of grain refinement caused by dendrite fragmentation. The fracture surface caused by fragmentation also makes more solid-liquid interfaces and their growth. In addition, the cases with different initial nuclear positions were compared. The grain growth in the low-temperature zone can be inhibited by the equiaxed grains' fragmentation at the high-temperature area (179.8 μm² and 14.7 % start at the center, 115.4 μm² and 9.4 % start at the high-temperature corner, 134.3 μm² and 10.9 % start at the low-temperature corner), which is another kind of grain refinement by the dendrite fragmentation. This kind of inhibition effect on grain growth in the low-temperature region will be enhanced with the increasing time interval between the two crystal nuclei’ appearance (179.8 μm² and 14.7 % when virtual grains appear at t = 4.3803 s and t = 4.3803 s, 134.3 μm² and 10.9 % at t = 4.0977 s and t = 3.9564 s, and 115.4 μm² and 9.4 % at t = 3.8151 s and t = 3.5325 s).
KW - Laser beam welding
KW - Electromagnetic
KW - Aluminum alloys
KW - Phase field method
KW - Equiaxed grain
KW - Dendrite fragmentation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656610
DO - https://doi.org/10.1016/j.cwe.2025.100014
SN - 3117-4159
VL - 35
IS - 1
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-65661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Kising, Pascal
A1 - Yang, Fan
A1 - Rethmeier, Michael
T1 - Prediction of weld pool and keyhole geometries in high-power laser beam welding through a physics-informed generative artificial intelligence approach
N2 - The weld pool and keyhole geometries are critical characteristics in evaluating the stability of the high-power laser beam welding (LBW) process and determining the resultant weld quality. However, obtaining these data through experimental or numerical methods remains challenging due to the difficulties in experimental measurements and the high computational demands of numerical modelling. This paper presents a physics-informed generative approach for predicting weld pool and keyhole geometries in the LBW process. With the help of a well experimentally validated numerical model considering the underlying physics in the LBW, the geometries of the weld pool and keyhole under various welding conditions are calculated, serving as the dataset of the generative model. A conditional variational autoencoder model is employed to generate realistic 2D weld pool and keyhole geometries from the welding parameters. We utilize a β-variational autoencoder model with the evidence lower bound loss function and include Kullback–Leibler divergence annealing to better optimize model performance and stability during training. The generated results show a good agreement with the ground truth from the numerical simulation. The proposed approach exhibits the potential of physics-informed generative models for a rapid and accurate prediction of the weld pool geometries across a diverse range of process parameters, offering a computationally efficient alternative to full numerical simulations for process optimization and control in laser beam welding processes.
KW - Laser beam welding
KW - Generative artificial intelligence
KW - Machine learning
KW - Numerical simulation
KW - Weld pool
KW - Keyhole dynamics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656621
DO - https://doi.org/10.2351/7.0001862
SN - 1042-346X
VL - 38
IS - 1
SP - 1
EP - 8
PB - Laser Institute of America
AN - OPUS4-65662
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Abbassi, Abdelouahad
A1 - Krenzer, Julius
A1 - Petrov, Eugene P.
A1 - Biesen, Lukas
A1 - Vasylyeva, Vera
A1 - Merzenich, Sarah
A1 - Resch-Genger, Ute
A1 - Müller, Thomas J. J.
T1 - Aroyl-S,N-ketene acetal-triarylamine bichromophores – intramolecular energy transfer and dual emission upon induced aggregation and encapsulation
N2 - Aroyl-S,N-ketene acetal-based bichromophores are synthesized by a catalytic aryl amination and their photophysics are studied in the solid state, in ethanol–water mixtures inducing aggregation, and after encapsulation in polystyrene nanoparticles. The dye substitution pattern controls aggregation-induced emission and intramolecular energy transfer efficiency, resulting in single-band or dual fluorescence and a strong increase in fluorescence quantum yield upon particle encapsulation.
KW - Fluorescence
KW - Dye
KW - Aggregation
KW - Photophysics
KW - Enhancement
KW - White light emission
KW - Energy transfer
KW - Quantum yield
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656700
DO - https://doi.org/10.1039/d5ra09361a
SN - 2046-2069
VL - 16
IS - 11
SP - 10255
EP - 10260
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilberg, Alec
T1 - Untersuchung und Kompensation des Size-of-Source Effektes der Thermografie zur Prozessüberwachung in der metallischen additiven Fertigung
N2 - Der Einsatz der Thermografie zur Prozessüberwachung in der additiven Fertigung von Metallen ist aktueller Schwerpunkt diverser Forschungsprojekte. Prozessbedingt können im Bauteil Risse, innere Spannungen und sonstige interne Fehlerstellen auftreten, deren Entstehung durch wichtige thermische Größen wie Phasenumwandlungstemperaturen, Abkühlgeschwindigkeiten und thermische Gradienten beeinflusst wird. Um diese Einflüsse zu untersuchen, ist eine möglichst genaue Messung dieser Parameter notwendig.
Neben den häufig betrachteten Einflüssen des Emissionsgrades, der Umgebungstemperatur und der atmosphärischen Absorption besteht ein weiterer Einfluss, hervorgerufen durch das optische System. Der Kameraaufbau, das verwendete Objektiv und Teilchen im Strahlengang können zur Beugung, Streuung, Reflektion und Aberration der elektromagnetischen Strahlung führen, wodurch die thermografische Messung verfälscht wird. Dies ist ein in der Pyrometrie intensiv erforschter Effekt und wird, aufgrund der Abhängigkeit zur betrachteten Objektgröße, als Size-of-Source Effekt bezeichnet und in dieser Arbeit untersucht.
Im Laser-Pulver-Auftragsschweißen (LPA) wird mittels eines Lasers auf einer Substratplatte ein Schmelzbad erzeugt und durch Einblasen von Metallpulver die lagenweise Fertigung von komplexen Bauteilen ermöglicht. Dabei können, je nach geometrischer Auflösung der Kamera, Größen des Schmelzbades im Bereich weniger Prozente der gesamten Bildfläche auftreten. Aus durchgeführten Referenzmessungen an Schwarzkörperstrahlern kann in der gleichen Größenordnung eine Abweichung der Strahlungswerte im zweistelligen Prozentbereich festgestellt werden. Daher ist in diesem Anwendungsfall der dadurch verursachte Fehler nicht zu vernachlässigen, weshalb auf Basis der Referenzmessungen eine Methode entwickelt wurde, um in Abhängigkeit der Größe des Objektes einen Faktor zur Kompensation des Size-of-Source Effektes zu berechnen.
In diesem Beitrag werden erste Ergebnisse dieser im Rahmen des DFG Projektes QT-LPA (Nr. 516965606) durchgeführten Arbeiten präsentiert.
T2 - DGZfP Jahrestagung 2025
CY - Berlin, Germany
DA - 26.05.2025
KW - SSE
KW - Thermografie
KW - Size of source Effect
PY - 2025
AN - OPUS4-65651
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilberg, Alec
T1 - Multispektrale Thermografie zur quantitativen Temperaturbestimmung im DED-LB/M Prozess
N2 - Additive Fertigungsverfahren bieten konstruktive Freiheiten, die mit konventionellen Herstellungsverfahren nur schwer zu realisieren sind. Durch die Möglichkeit hochkomplexe Bauteile aus Metall fertigen zu können, stellt die additive Fertigung in vielen Industriezweigen eine vielversprechende Fertigungsalternative da. Allerdings treten prozessbedingt hohe Temperaturgradienten und schnelle Phasenumwandlungen auf, die maßgeblich entscheidend für die Mikrostruktur und die Bildung von internen Spannungen, Rissen und weiteren Defekten sind. Diese Effekte wirken sich direkt auf die mechanischen Eigenschaften der gefertigten Bauteile aus und verdeutlichen die Notwendigkeit einer zuverlässigen Bauteilprüfung. Dabei sind nachgelagerte Verfahren in der Regel zeit- und kostenaufwändig, weshalb die Anwendung von in-situ Verfahren zur Qualitätssicherung im Fokus diverser Forschungsprojekte steht.
Die Thermografie erlaubt die orts- und zeitaufgelöste Messung der im Prozess auftretenden Temperaturfelder. Allerdings müssen die tatsächlich gemessenen digitalen Sensorwerte mittels geeigneter radiometrischer Modelle in Temperaturen umgewandelt werden. Da diese Modelle in der Regel auf Basis von Messungen an Schwarzkörperstrahlern kalibriert werden, kann dieses Vorgehen nur zufriedenstellende Werte liefern, sofern der Emissionsgrad des zu messenden Objektes bekannt ist. Während in statischen Anwendungen häufig ein konstanter Materialreferenzwert hinreichend befriedigende Ergebnisse liefert, ist man in der additiven Fertigung mit dem Problem konfrontiert, dass der Emissionsgrad lokal in kürzester Zeit starke Änderungen durchläuft. Beeinflusst wird dieser Effekt unter anderem durch Temperatur, Phasenzustand und Oberflächenzustand.
Das hier vorgestellte Verfahren nutzt Referenzmessungen des Emissionsgrades in Abhängigkeit von Temperatur, Winkel und Phasenzustand, um in einem DED-LB/M-Prozess (auch Laser-Pulver-Auftragschweißen, LPA) sowohl den Emissionsgrad als auch die tatsächliche Temperatur orts- und zeitaufgelöst zu bestimmen. Grundlage hierfür sind multispektrale thermografische Messungen, bei denen (quasi-) synchron in acht unterschiedlichen Wellenlängenbereichen gemessen wird.
In diesem Beitrag werden Ergebnisse der im Rahmen des DFG-Projektes QT-LPA (Nr. 516965606) durchgeführten Arbeiten präsentiert.
T2 - Thermo25
CY - Garching bei München, Germany
DA - 11.11.2025
KW - Thermografie
KW - TES
KW - Multispektral
KW - DED-LB/M
KW - Laserpulverauftragschweißen
PY - 2025
AN - OPUS4-65652
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ziegler, Mathias
A1 - Strobach, L.
T1 - Infrarotreflektographie und Blitzthermographie zur Sichtbarmachung von historischen Farbschichten am Flugzeug Bücker Bü 181 Bestmann
N2 - Die Geschichte eines Flugzeuges ist häufig von unterschiedlichen Nutzungsphasen geprägt. Zum Beispiel ist der Wechsel des Eigentümers eines Flugzeuges häufig mit umfassenden Veränderungen der Farbgebung und Kennzeichnung verbunden. Wenn ein Flugzeug in die Sammlung eines Museums aufgenommen wird, zeigt es entweder den letzten Einsatzzustand oder andere zu späteren Zeiten durchgeführte Reparaturen auf seiner Oberfläche. Oft befinden sich unterhalb dieser letzten äußeren Schicht, ältere Spuren der Nutzung. Um diese verdeckt liegenden Lackierungen sichtbar zu machen, können die Verfahren der Infrarotreflektographie und der aktiven Thermographie eingesetzt werden. Die Infrarotreflektographie wird häufig in der Gemälderestaurierung eingesetzt, um zum Beispiel Vorzeichnungen sichtbar zu machen. Die aus der industriellen zerstörungsfreien Prüfung bekannten Verfahren der aktiven Thermographie fanden bisher überwiegend im Bereich der Bauwerksuntersuchungen Anwendung. Erste Ergebnisse zu Farbuntersuchungen an historischen Flugzeugen mit den beiden Verfahren fanden am Deutschen Museum München in Zusammenarbeit mit der TU-München statt. Ein Projekt der HTW-Berlin mit der Bundesanstalt für Materialforschung und –prüfung (BAM) und dem Militärhistorischen Museum Flugplatz Berlin-Gatow greift diese Anwendungsidee auf und vergleicht beide Verfahren. Am Beispiel des Flugzeuges Bücker Bü 181 Bestmann können die Möglichkeiten, Grenzen und Potentiale der Technologien zum gegenwärtigen Entwicklungsstand verdeutlicht werden.
T2 - Material Truth
CY - Magdeburg, Germany
DA - 04.03.2026
KW - Aktive Thermographie
KW - Flugzeuggeschichte
KW - Zerstörungsfreie Prüfung (ZfP)
KW - Infrarotreflektographie
PY - 2026
AN - OPUS4-65658
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
T1 - Quantitative Auswertemöglichkeiten bei der spektralen Bestrahlung – Berechnung des Wirkungsspektrums
N2 - Für die Bewertung des Wellenlängeneinflusses auf die Alterungsvorgänge bei der Bestrahlung UV- oder lichtempfindlicher Materialien kann die Methode der spektralen Bestrahlung angewendet werden. Im Prinzip wird dabei das linear dispergierte Spektrum einer Strahlenquelle mit kontinuierlichem Spektrum (z.B. Xe-Lampe) auf eine Probenoberfläche abgebildet, so dass Ort einer Materialänderung und Wellenlänge der Bestrahlung einander zugeordnet werden können. Nachfolgende lokal-auflösende Analysemethoden ermitteln eine Eigenschaftsänderung an einem spezifischen Ort der Probe, aus dem sich dann die Bestrahlungswellenlänge ergibt.
Der verwendete Aufbau wird beschrieben. Es wird an einem ausgewählten Beispiel gezeigt, wie durch geeignete Anbindung eines Messsystems zur Bestimmung der spektralen Bestrahlungsstärke und ortsaufgelöste Messungen der Eigenschaftsänderungen eine quantitative Auswertung realisiert werden kann. Der Einfluss nichtlinearer Alterungsverläufe wird diskutiert. Grenzen der Methode werden aufgezeigt und Erweiterungsmöglichkeiten dargestellt.
T2 - 46. Jahrestagung der GUS
CY - Stutensee-Blankenloch, Germany
DA - 22.03.2017
KW - UV-Bestrahlung
PY - 2017
AN - OPUS4-42577
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - BOOK
A1 - Geburtig, Anja
A1 - Manier, G.
A1 - Cäsar, J.
A1 - Herlyn, J.
A1 - Hülsmann, Ph.
A1 - Köhl, M.
A1 - Reichert, Th.
A1 - Ruoss, H.
A1 - Rüther, N.
A1 - Schönlein, A.
T1 - Wasser und Materialeigenschaften
N2 - In der Gesellschaft für Umweltsimulation GUS e.V. erarbeiten Fachleute aus Wissenschaft und Industrie in freiwilliger Selbstverantwortung Leitfäden und Bücher zur, Umweltsimulation und zur Wirkungssimulation von Umwelteinflüssen.
Diese beschreiben den Stand der Technik bzw. Stand der Wissenschaft und dienen als Anleitung für Umweltingenieure und Personen, die sich in die Arbeitsgebiete Produktqualifikation und Umweltsimulation einarbeiten und einiesen wollen.
Folgende Themenschwerpunkte werden in diesem Leitfaden behandelt: Wasser und seine Eigenschaften, Phasenübergänge, Transportvorgänge, Änderung von Materialeigenschaften durch Wasser, Messmethoden.
KW - Wasser
KW - Materialien
PY - 2019
SN - 978-3-9818507-4-1
N1 - Belegexemplar liegt bei Frau Geburtig.
SP - 1
EP - 445
PB - Stober GmbH
CY - Eggenstein
AN - OPUS4-48325
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engelking, Lorenz
A1 - Eissel, A.
A1 - Madia, Mauro
A1 - Schröpfer, Dirk
A1 - Treutler, K.
A1 - Kruse, Julius
A1 - Kannengießer, Thomas
A1 - Wesling, V.
T1 - Influence of ultrasonic-assisted milling on surface integrity of additively manufactured components using MSG processes
N2 - Additive manufacturing (AM) is increasingly used for producing complex metallic components. Subsequent machining is essential to achieve final geometries and surface conditions. The resulting surface integrity, particularly the near-surface residual stress state, plays a crucial role in component performance and fatigue life. This study investigates the potential of ultrasonic-assisted milling (USAM), a hybrid machining process, to improve surface integrity and machinability compared to conventional milling (CM). Three materials were investigated, two difficult-to-cut materials CoCr26Ni9Mo5W and FeNi36 and a low-alloy steel S355J2C. The CoCr26Ni9Mo5W and FeNi36 were additively manufactured via Directed Energy Deposition (DED)-Arc and then machined with varying cutting speeds and feed rates within a Design of Experiments. USAM exhibited enhanced machinability and surface integrity, particularly at low cutting speeds, by reducing cutting forces up to 40% and shifting near-surface residual stresses from tensile to compressive. For S355J2C, USAM reduced cutting forces by approximately 45% and induced near-surface compressive residual stresses up to approximately −700 MPa. Rotating bending tests (DIN50100) show that USAM increases the technical fatigue limit from 307 MPa (CM) to 341 MPa (USAM), i.e., by ∼11%. These findings highlight the advantages of ultrasonic assistance in post-AM machining, offering enhanced fatigue performance and surface quality for various metallic materials.
T2 - 4th International Conference on Advanced Joining Processes 2025
CY - Coimbra, Portugal
DA - 16.10.2025
KW - Ultrasonic-assisted milling
KW - Residual stress
KW - Surface integrity
PY - 2026
DO - https://doi.org/10.1177/14644207261416395
SP - 1
EP - 12
PB - Sage Journals
AN - OPUS4-65682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jesus, Vinicius D.
A1 - Merizio, Leonnam G.
A1 - Galleani, Gustavo
A1 - Raffy, Guillaume
A1 - Carpentier, Mathis
A1 - Petit, Yannick
A1 - Cardinal, Thierry
A1 - de Camargo, Andrea S. S.
T1 - Energy transfer from Ag species to Nd 3+ in Ga–fluoride–phosphate glasses: near-infrared emission enhancement via controlled heat treatment and femtosecond laser inscription
N2 - Gallium fluoride–phosphate glasses are promising materials with wide optical transmission window, high volumetric density, and the ability to accommodate high concentrations of rare earth dopant ions within a tailored fluoride-rich coordination environment, resulting in high emission cross sections. In this work, the compositional system 25Ga(PO3)3–20ZnF2–30BaF2–(25–x–y)SrF2–xAgNO3–yNdF3 (x = 0–10 mol%, y = 0 or 1 mol%) was studied to understand how silver species affect the near-infrared (NIR) emission of Nd3+ ions, when the glasses are subjected to controlled heat treatment and to femtosecond direct laser writing (DLW). The glasses were obtained via the melt-quenching technique and characterized by DSC, XRD, UV-Vis-NIR absorption, and PL spectroscopy. The as-prepared glasses show broad UV-Vis excitation and emission bands arising from the coexistence of Ag+ ions and ionic Ag pairs. In samples with 10 mol% Ag+, brownish coloration and modified emission profiles indicated Ag nanoparticle formation at the surface. Heat treatment promoted the conversion of isolated Ag+ into ionic pairs, producing broadband emissions tunable by excitation wavelength and Ag+ concentration. In co-doped samples, Nd3+ introduced absorption dips in the Ag-related UV-Vis bands, consistent with energy transfer, which was further confirmed by shortened Ag excited-state lifetimes and increased Nd3+ NIR emission under UVVis excitation. In order to control the spatial distribution and size of Ag aggregates (nanoclusters, NCs) and to increase the energy transfer efficiency to Nd3+, femtosecond direct laser writing (DLW) was employed to co-doped glasses with 3 and 5 mol% Ag+. This approach enabled three-dimensional localized growth of Ag NCs with sub-micron spatial control. In the laser processed regions, the NIR emissions of Nd3+ at 900 and 1060 nm were significantly enhanced, clearly evidencing enhanced energy transfer from the localized laserinduced Ag-NCs to the Nd3+ ions. These findings suggest the possibility of tailoring high optical contrast near-IR emissions in glasses, enabling progress in advanced photonic applications.
KW - Neodymium
KW - Silver
KW - Fluoride phosphate glasses
KW - Direct laser writing
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656888
DO - https://doi.org/10.1039/d5ma01430a
SN - 2633-5409
SP - 1
EP - 14
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65688
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Engelking, Lorenz
A1 - Hälsig, A.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Hensel, J.
T1 - Influence of build‑up height on residual stresses in additive repair and modification using DED‑Arc with high‑strength filler metals
N2 - Directed energy deposition (DED)-Arc is suitable for the hybrid additive manufacturing, modification and repair of large metal components with high deposition rates. Residual stresses and distortion are of central importance when characterizing the manufactured components and the sensitive transition area between additive manufactured (AM) component and semifinished product. Residual stresses caused by the thermal cycles during the manufacturing process can impair the mechanical properties of the manufactured parts and can lead to component failure, especially for high-strength steels. Therefore, understanding and controlling residual stresses, when combining different base and feedstock materials, is critical to improve the quality and efficiency of the hybrid DED-Arc process. This article deals with the influence of the build-up height on the residual stress distribution of additively manufactured components with a selected base and feedstock material from commercial high-strength steels. Using a robot-assisted DED-system and a controlled short arc, AM welding experiments were carried out with close to the application parameters at working temperature (200 °C) and heat input (650 kJ/m). Five hybrid AM specimens (AM wall on upright structural steel plate) were produced using a one bead per layer strategy and selected AM-wall heights between 15 and 300 mm. The influence of the AM build height on the longitudinal residual stress in the whole hybrid AM specimen (in welding direction) was analyzed and discussed. All experiments exhibit comparable stress distributions in the area of the substrate plate up to the heat-affected zone (HAZ) and the transition zone, regardless of the building height. The height significantly influences the residual stress distribution of the deposited AM-component. Tensile residual stresses with a maximum range between 300and 400 MPa were always found in the last approx. 18 component layers (upper 40 mm). This is due to restraint of the shrinking of the top layers by the layers below. The lower layers show homogeneous residual stress distributions characterized by low compressive stresses due to the process-related tempering during the deposition of each layer on top of each other. As a result, the significant difference between the various AM build-up heights of the hybrid AM specimens is the extent (or height) of this tempered zone with low compressive stresses. These correlations contribute to the understanding of residual stress development with increasing structure height or ratio of component heights of substrate semi-finished product and AM component in hybrid additive manufacturing.
T2 - 78th IIW Annual Assembly and International Conference
CY - Genoa, Italy
DA - 22.06.2025
KW - DED-Arc
KW - Residual stress
KW - Heat control
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656793
DO - https://doi.org/10.1007/s40194-026-02417-y
SN - 1878-6669
SP - 1
EP - 12
PB - Spriner
AN - OPUS4-65679
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Kaplan, Alexander
A1 - Rethmeier, Michael
T1 - Digitalisation and Carbon Footprint Evaluation of Gas Metal Arc Welding and Wire-Arc Directed Energy Deposition
N2 - This paper showcases how a holistic approach to digitalisation enables data-driven welding applications, exemplarily for a gas metal arc welding (GMAW) laboratory. The workflow integrates advanced process monitoring, synchronised multi-sensor data acquisition and tools for data analytics. A welding domain-specific data exchange format weldx is presented that unifies and aggregates the data sets acquired during process monitoring with final component quality metrics, supporting reuse, traceability, and reproducibility. Two case studies illustrate the approach. First, GMAW parameters are adaptively adjusted according to local seam geometry to compensate joint-preparation deviations from nominal values typical for large-scale steel fabrication. Second, the seamless data aggregation along the welding production chain enables an automatic life-cycle assessment (LCA), quantifying the environmental impacts of additive manufacturing with DED Arc/M and attributing the dominant contributors to the carbon footprint. Collectively, the results indicate that a fully integrated experimental set-up together with standardised data structures and scalable analytics can couple monitoring, control, and sustainability, thereby realising the potential of digitalisation for high-quality and environmentally informed welding production.
KW - Digitalisation
KW - Arc welding
KW - DED-arc
KW - Life Cycle Assessment
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656812
DO - https://doi.org/10.1088/1757-899X/1342/1/012067
SN - 1757-8981
VL - 1342
IS - 1
SP - 1
EP - 15
PB - IOP Publishing
AN - OPUS4-65681
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
T1 - Messung der effektiven UV-Bestrahlung bei der Bewitterung von Polymeren
N2 - Bei der Bestrahlung und Bewitterung von polymeren Werkstoffen wird die Degradation durch eine Absorption von Strahlung initiiert und meistens durch weitere Klimagrößen, wie z.B. Wärme, Feuchte und atmosphärische Gase beeinflusst. Die Messung einer effektiven Bestrahlungsstärke und ihre zeitliche Integration sind deshalb von großer Bedeutung.
Photochemische Prozesse werden beim Sehen oder allgemeiner bei Farbstoffen schon durch sichtbare (VIS) Strahlung, dagegen bei der Erythembildung der Haut und der Photodegradation von Polymeren erst durch die energiereicheren Photonen der ultravioletten (UV) Strahlung initiiert. Die spektrale Empfindlichkeit des Auges und die Erythembildung sind im VIS- bzw. UV-Bereich sehr stark wellenlängenabhängig, was durch die Angabe der mit der spektralen Hellempfindlichkeit V() des Auges bewerteten VIS-Strahlung in Lux (lx) bzw. die mit der Erythem-Wirkfunktion bewertete UV Strahlung als dimensionsloser UV-Index berücksichtigt wird. Spektrale Empfindlichkeiten.
Die Photodegradation von Polymeren ist im UV-Bereich ebenfalls stark wellenlängenab-hängig, was bisher nicht berücksichtigt wurde. Seit Mitte der 70er Jahre, als die lx- bzw lxh- Messung bei der Strahlungsbeanspruchung langsam durch die Ermittlung der radiometrischen UV-Bestrahlungsstärke bzw. der UV-Bestrahlung im gesamten UV-Bereich abgelöst wurde, gab es hier bei der Bewitterungsprüfung keine weiteren Fortschritte auf dem Gebiet der Charakterisierung der Strahlungsbeanspruchung im UV-Bereich.
Seit Jahren liegen zahlreiche Ergebnisse über die spektrale Empfindlichkeit von Photo-degradationsprozessen vor, die zeigen, dass die spektrale Empfindlichkeit im Bereich der Globalstrahlung bei ca. 300 nm, am größten ist und im langwelligen UV-Bereich bei ca. 400 nm gegen Null geht. Die Messungen der radiometrischen Größen UV-Gesamt-bestrahlungsstärke und UV-Gesamtbestrahlung erfasst deshalb über weite Wellen-längenbereiche Strahlungsanteile, die für die Photodegradation bedeutungslos sind und mittelt über potenziell bedeutsame Änderungen im kurzwelligen UV-Bereich hinweg.
Es wird das Konzept eines neuen UV-Radiometers vorgestellt, dessen spektrale Empfindlichkeit einer mittleren spektralen Empfindlichkeit der Photodegradation von Polymeren entspricht. Die effektive UV-Bestrahlungsstärke und UV-Bestrahlung kann dadurch wesentlich genauer erfasst werden.
T2 - 48. Jahrestagung der GUS 2019
CY - Stutensee, Germany
DA - 27.03.2019
KW - UV-Bestrahlungsstärke
PY - 2019
AN - OPUS4-49712
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
T1 - Evaluation of Outdoor Exposures by means of Exposure Response Functions
N2 - Outdoor exposure tests are a common tool to evaluate the weathering resistance of a polymeric material or component. However, they have only a limited validity, mainly due to the limited reproducibility of the weather as well as of the bad adaptability to other exposure sites. Typically, an outdoor exposure is characterized by the measured radiant exposure; sometimes averaged temperature data are added. These can be – separately – related to long-term annual means, to get an idea on the severity of the exposure.
However, as for polymeric ageing, irradiance and temperature act simultaneously, such severity of an outdoor exposure could be better described by a computed property change of a similar material, which is calculated from the hourly irradiance and temperature values on the base of established exposure response functions.
In this way, various outdoor exposures are evaluated. For several exposure sites, annual deviations of the ageing amount are related to annual mean values, to evaluate the weathering reproducibility at the exposure site. Additionally, correlations to relevant weather parameters are illuminated. Also some specific exposure conditions, such as tilt angle, are tested. Compared to the use of weathering reference materials, this procedure unfavourably depends on the availability of a suited control as well as on the quality of the established exposure response function. In contrast, it enables a later exposure evaluation, on the base of documented weather data, if for instance no reference material was exposed.
T2 - 8th European Weathering Symposium
CY - Vienna, Austria
DA - 20.09.2017
KW - Photodegradation
KW - Weathering
KW - Service life prediction
PY - 2017
AN - OPUS4-42576
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachtendorf, Volker
A1 - Barthel, Anne-Kathrin
A1 - Geburtig, Anja
A1 - Trubiroha, P.
ED - Reichert, T.
T1 - Low-Temperature Irradiation Experiments for PE, PA, and PC Matrices
N2 - In this paper, we demonstrate the effects of radiation exposures of polymeric materials with UV-A 340 nm lamps (ISO 4892-3, Type 1A) at -10 °C in comparison to an irradiation at +50 °C using a Global UV Test 200 fluorescent lamp device from Weiss Umwelttechnik GmbH, which incorporates an active cooling appliance. While the effects at -10 °C actually are lower than at + 50°C their extent was clearly beyond expectations.
T2 - 8th European Weathering Symposium
CY - Vienna, Austria
DA - 20.09.2017
KW - Artificial weathering
KW - Irradiation
KW - Low-temperature
KW - Photo-oxidation
KW - Polyamide
KW - Polycarbonate
KW - Polyethylene
PY - 2017
SN - 978-3-9818507-1-0
VL - 18
SP - Paper 22, 319
EP - 329
PB - Thomas Würtz Grafik Design
CY - Karlsruhe
AN - OPUS4-42130
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kalbe, Ute
A1 - Krüger, Oliver
A1 - Bandow, Nicole
A1 - Geburtig, Anja
ED - Reichert, Thomas
T1 - Laboratory Weathering Test for Simulating the Leaching from Artificial Sporting Grounds
N2 - In order to estimating the amount and kind of emissions from polymeric sporting tracks a laboratory test was developed in BAM that combines artificial weathering and subsequent batch and column tests [1, 2, 3]. The goal consisted in nvestigating a possible change of emissions into soil and groundwater of a new sporting ground as a function of ageing and egradation of the system. At various stages of the weathering, the samples were removed and subjected to especially designed column extraction tests for the solid samples. Both these extracts and the accumulated rainwater run-off of the weathering device were subjected to analytical tests of their ingredients. The overall aim of the test consisted in developing ontrollable, reproducible, and standardisable conditions and methods of investigation that would allow an estimation of the emissions in the course of outdoor application of about five years.
T2 - 7th European Weathering Symposium. Natural and Artificial Ageing of Polymers
CY - Naples, Italy
DA - 16.09.2015
KW - artificial weathering
KW - emission
KW - leaching
KW - sporting track
KW - degradation
KW - ageing
KW - rubber
KW - extraction
PY - 2015
SN - 978-3-9816286-6-1
VL - CEES 17
SP - 195
EP - 208
PB - Thomas Würtz
CY - Karlsruhe, Germany
AN - OPUS4-35401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
T1 - Testing of HDPE containers for dangerous goods after outdoor exposure
N2 - Focus areas of BAM as well as testing results of HDPE containers for dangerous goods after outdoor exposure of were presented.
T2 - 70th CEEES Meeting
CY - Hørsholm, Danmark
DA - 13.11.2018
KW - HDPE
KW - Dangerous goods
KW - Chemical resistance
PY - 2018
AN - OPUS4-47032
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
A1 - Wachtendorf, Volker
A1 - Trubiroha, P.
T1 - Quantitative Auswertemöglichkeiten bei der spektralen Bestrahlung – Berechnung des Wirkungsspektrums
N2 - Für die Bewertung des Wellenlängeneinflusses auf die Alterungsvorgänge bei der Bestrahlung UV- oder lichtempfindlicher Materialien kann die Methode der spektralen Bestrahlung angewendet werden. Im Prinzip wird dabei das linear dispergierte Spektrum einer Strahlenquelle mit kontinuierlichem Spektrum (z.B. Xe-Lampe) auf eine Probenoberfläche abgebildet, so dass Ort einer Materialänderung und Wellenlänge der Bestrahlung einander zugeordnet werden können. Nachfolgende lokal-auflösende Analysemethoden ermitteln eine Eigenschaftsänderung an einem spezifischen Ort der Probe, aus dem sich dann die Bestrahlungswellenlänge ergibt.
Der verwendete Aufbau wird beschrieben. Es wird an einem ausgewählten Beispiel gezeigt, wie durch geeignete Anbindung eines Messsystems zur Bestimmung der spektralen Bestrahlungsstärke und ortsaufgelöste Messungen der Eigenschaftsänderungen eine quantitative Auswertung realisiert werden kann. Der Einfluss nichtlinearer Alterungsverläufe wird diskutiert. Grenzen der Methode werden aufgezeigt und Erweiterungsmöglichkeiten dargestellt.
T2 - 46. Jahrestagung der GUS
CY - Stutensee-Blankenloch, Germany
DA - 22.03.2017
KW - Bewitterung
KW - Spektrale Bestrahlung
KW - Kunststoffe
PY - 2017
SN - 978-3-9816286-9-2
SP - 91
EP - 99
AN - OPUS4-39595
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oliveira Menezes, Letícia Gonçalves
A1 - Trajano Silveira, Beatriz Aiub
A1 - de Castro Raucci, Larissa Moreira Spinola
A1 - Martorano, Antônio Secco
A1 - de Oliveira, Paulo Tambasco
A1 - Arai, Marylyn Setsuko
A1 - de Camargo, Andréa Simone Stucchi
A1 - Hannig, Christian
A1 - Sterzenbach, Torsten
A1 - Brighenti, Fernanda Lourenção
A1 - de Oliveira, Analú Barros
A1 - Moraes, João Carlos Silos
A1 - Danelon, Marcelle
T1 - Functional glass ionomer cement modified with phosphate and zinc oxide nanoparticles: in vitro insights into physicomechanical behavior, cytotoxicity and antimicrobial activity
N2 - Objectives: To evaluate the effect of incorporating zinc oxide nanoparticles (ZnONPs) and sodium trimetaphosphate microparticles (TMP) into resin-modified glass ionomer cement (RMGIC) on its physicomechanical, microbiological, and cytotoxic properties.
Methods: Six groups were prepared: 1) RMGIC (Fuji II LC); 2) RMGIC-1.0 %ZnONPs; 3) RMGIC-2.0 %ZnONPs; 4) RMGIC-14.0 %TMP; 5) RMGIC-1.0 %ZnONPs-14.0 %TMP; and 6) RMGIC-2.0 %ZnONPs-14.0 %TMP. Tensile/diametral compressive strengths (TS, DCS), surface hardness (SH) and degree of monomer conversion (%DC) were evaluated in 24 h and 7 days. Fluoride (F) release was assessed over 15 days using alternating demineralizing/remineralizing solutions. Antimicrobial/antibiofilm activity against S. mutans (UA159) was assessed through adhesion, biofilm growth measurements, and XTT assays. Cytotoxicity was tested on MDPC23 odontoblasts using the resazurin assay.
Results: The DCS for the RMGIC-2.0 %ZnONPs group was 22.5 % higher when compared to RMGIC after 24 h (p <0.05); after 7 days, RMGIC-2.0 %ZnONPS-14.0 %TMP group was 23.4 % higher than RMGIC (p < 0.05). For TS after 7 days, the RMGIC-2.0 %ZnONPs-14.0 % TMP group showed the highest values (37 % and 55.4 %) than RMGIC and RMGIC-14.0 % TMP, respectively (p < 0.05). At 24 h, the RMGIC-2.0 %ZnONPs-14.0 %TMP Group showed the highest SH among all groups (p < 0.05). The greatest effect on reducing bacterial viability was observed for the RMGIC-2.0 %ZnONPs-14.0 %TMP group (p < 0.05). For cytotoxicity analysis, at 24 h, the RMGIC-1.0 %ZnONPs-14.0 %TMP group showed the highest cytocompatibility (p < 0.05). At 48 and 72 h, RMGIC-1.0 %ZnONPs, RMGIC-2.0 %ZnONPs, RMGIC-1.0 %ZnONPs-14.0 %TMP and RMGIC-2.0 %ZnONPs-14.0 %TMP groups showed the lowest cytotoxicity (p < 0.05)
KW - Phosphate and zinc oxide nanoparticles
KW - Glass ionomer
PY - 2026
DO - https://doi.org/10.1016/j.jdent.2025.106307
SN - 0300-5712
VL - 165
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-65692
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghadamyari, Marzieh
A1 - Ebrahim Hosseini, Hossein
A1 - Michálková, Monika
A1 - de Camargo, Andréa Simone Stucchi
A1 - Cao, Jiangkun
A1 - Galusek, Dušan
A1 - Chukova, Oksana
A1 - Wondraczek, Lothar
A1 - Jacobsohn, Luiz Gustavo
A1 - Klement, Róbert
T1 - Broadband visible emission in undoped K2ZnGeO4 by near UV and X-ray excitation
N2 - Self-activated phosphors (SAP) have attracted significant attention for a wide range of applications, including lighting, displays, scintillators, lasers, luminescence-based sensors, bioimaging, drug delivery, and luminescent security inks. In this work, we report a new white emitting SAP, α-K2ZnGeO4, synthesized by high-temperature solid-state reaction. The phosphor crystallizes in a single-phase orthorhombic structure and consists of irregularly shaped particles. Under ultraviolet (UV) and X-ray excitation the sample exhibits broad yellowish-white emission spanning the 350–800 nm spectral range, with a long-wavelength tail extending into the near-infrared region, overlapping the biological window. Average lifetime values of 20.4 and 22.6 μs were determined from the fluorescence decay curves monitored at the centre of the band (550 nm), upon excitation at 272 and 377 nm, respectively. Additionally, the decay curve of a distinct spectral feature, peaked at 385 nm, was studied upon 272 nm excitation, yielding a lifetime of 2.3 μs. The role of structural defects (donors: VO and Zni; acceptors: VZn, VGe, and Oi) in the luminescence of α-K2ZnGeO4 was also investigated. Photoluminescence spectra recorded under 366 nm and 377 nm excitation yielded CIE 1931 chromaticity coordinates of (x, y) = (0.40213, 0.46943) and (0.39326, 0.47611), respectively. The values are almost identical and correspond to yellowish-white emission, highlighting the suitability of the material as a yellowish-white phosphor in white light-emitting diodes (wLEDs).
KW - Broadband emitter
KW - K2ZnGeO4
KW - X-ray excitation
PY - 2026
DO - https://doi.org/10.1016/j.ceramint.2026.01.063
SN - 0272-8842
VL - 52
IS - 7
SP - 8658
EP - 8669
PB - Elsevier Ltd.
AN - OPUS4-65691
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rex, Tobias
A1 - Vilela, Raquel R. C.
A1 - Bauer, Nadine
A1 - Hepp, Alexander
A1 - de Camargo, Andrea S. S.
A1 - Kiefer, Friedemann
A1 - Strassert, Cristian A.
T1 - Host–Guest Nanoparticles Incorporating a Fluorophore-Conjugated Pt(II) Complex: A Ratiometric Dual Emitter Performing as a Self-Referenced Oxygen Reporter
N2 - Ratiometric optical sensors, which provide real-time measurements by comparing the intensities of two spectrally separated emission bands, are highly effective for monitoring oxygen levels. By combining oxygen-independent and oxygensensitive emission characteristics, they offer accurate quantification, distinguishing them from other sensor types. In this work, we designed a ratiometric optical sensor concept based on a biscyclometalated platinum(II) complex coupled with an organic naphthalonitrile-based fluorophore and incorporated it into mesoporous silica nanoparticles. This encapsulation strategy significantly improved the stability and water-dispersibility of the otherwise hydrophobic coordination compound while preventing aggregation and enhancing its photophysical properties. Both the free molecule and its nanoparticle-encapsulated form were characterized, revealing high sensitivity to oxygen variations with the unique feature of self-referenced ratiometric readout. The sensor’s response was effectively measured at the single-particle level using photoluminescence microscopy, providing temporally and spatially resolved oxygen readouts. The versatility of the system was demonstrated across different experimental setups, including suspensions, solids, and agarose-embedded forms, highlighting is adaptability to a wide range of applications. This system holds significant promise for advanced oxygen monitoring, offering a reliable tool for high-resolution detection in complex environments with multiple orthogonal readouts.
KW - Oxygen sensing
KW - Ratiometric luminescence
KW - Platinum (II) complex
KW - Dual emitter probe
KW - Mesoporous silica nanoprticles
PY - 2026
DO - https://doi.org/10.1021/acsaom.5c00262
SN - 2771-9855
VL - 4
IS - 2
SP - 332
EP - 342
PB - American Chemical Society (ACS)
AN - OPUS4-65689
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saeed, A. M.
A1 - Saied, M. A.
A1 - Szymoniak, Paulina
A1 - Altmann, Korinna
A1 - Schönhals, Andreas
A1 - Fahmy, Alaa
T1 - High performance novel polyelectrolyte membrane consisting of polyvinyl alcohol-phenylsilanol-polypyrrole
N2 - The synthesis of composite membranes based on PVA, PPy, and sulfonated–hydrolyzed TMPS was investigated for application in proton–exchange membrane fuel cells. FT–IR confirmed the hydrolysis of TMPS through the appearance of Si–OH vibrations, disappearance of Si–O–CH3 bands, reduced CH3 stretching intensity (2840 cm− 1), and successful sulfonation of the phenyl ring (1030 cm− 1). XPS verified the introduction of sulfonic acid groups by identifying S2p peaks between 166–170 eV. Scanning electron microscopy (SEM) showed an incorporation of PPy and that the membrane morphology altered by silanol leading to an increased surface roughness and inducing phase separation in comparison to pure PVA. The PVA–PPy–Si membrane which did not undergo phase separation demonstrated improved mechanical stability (maximum stress 5.91 MPa), reduced methanol uptake (22%, lower than Nafion’s 30%), and enhanced thermal resistance compared to PVA–PPy and PVA–Si. It also exhibited a high ion–exchange capacity (1.5mmol g− 1, exceeding Nafion® at 0.9mmol g− 1 ) and a proton conductivity of 0.036 S/cm, twice that of Nafion 117. These combined properties identify the PVA–PPy–Si composite as a promising high–performance polyelectrolyte membrane for fuel cell applications.
KW - Polyelectrolyte membrane
PY - 2026
DO - https://doi.org/10.1016/j.apsusc.2026.166495
SN - 1873-5584
VL - 731
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-65627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -