TY - JOUR A1 - Meng, Xiangmeng A1 - Bachmann, Marcel A1 - Yang, Fan A1 - Rethmeier, Michael T1 - Toward prediction and insight of porosity formation in laser welding: A physics-informed deep learning framework N2 - The laser welding process is an important manufacturing technology for metallic materials. However, its application is often hindered by the occurrence of porosity defects. By far, an accurate prediction of the porosity defects and an insight into its formation mechanism are still challenging due to the highly nonlinear physics involved. In this paper, we propose a physics-informed deep learning (PIDL) framework by utilizing mechanistic modeling and experimental data to predict the porosity level during laser beam welding of aluminum alloys. With a proper selection of the physical variables (features) concerning the solidification, liquid metal flow, keyhole stability, and weld pool geometry, the PIDL model shows great superiority in predicting the porosity ratio, with a reduction of mean square error by 41 %, in comparison with the conventional DL model trained with welding parameters. Furthermore, the selected variables are fused into dimensionless features with explicit physical meanings to improve the interpretability and extendibility of the PIDL model. Based on a well-trained PIDL model, the hierarchical importance of the physical variables/procedures on the porosity formation is for the first time revealed with the help of the Shapley Additive Explanations analysis. The keyhole ratio is identified as the most influential factor in the porosity formation, followed by the downward flow-driven drag force, which offers a valuable guideline for process optimization and porosity minimization. KW - Laser beam welding KW - Physics-informed deep learning KW - Porosity prediction KW - Feature fusion KW - Hierarchical importance PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624708 DO - https://doi.org/10.1016/j.actamat.2025.120740 VL - 286 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-62470 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krahl, T. A1 - Beer, F. A1 - Relling, A. A1 - Gawlitza, Kornelia A1 - Rurack, Knut A1 - Kemnitz, E. T1 - Toward Luminescent Composites by Phase Transfer of SrF2 :Eu3+ Nanoparticles Capped with Hydrophobic Antenna Ligands N2 - Transparent dispersions of hydrophobic SrF2 :Eu3+ nanoparticles in cyclohexane with up to 20% europium were obtained by fluorolytic sol-gel synthesis followed by Phase transfer into cyclohexane through capping with sodium dodecylbenzenesulfonate (SDBS). The particles were characterized by TEM, XRD and DLS as spherical objects with a diameter between 6 and 11 nm in dry state. 1H-13CP MAS NMR experiments revealed the binding of the anionic sulfonate head group to the particle surface. The particles show bright red luminescence upon excitation of the aromatic capping agents, acting as antennas for an Energy transfer from the benzenesulfonate unit to the Eu3+ centers in the particles. This synthesis method overcomes the current obstacle of the fluorolytic sol-gel synthesis that transparent dispersions can be obtained directly only in hydrophilic solvents. To demonstrate the potential of such hydrophobized alkaline-earth fluoride particles, transparent luminescent organic-inorganic composites with 10% SrF2 :Eu3+ embedded into polyTEGDMA, polyBMA, poly-BDDMA and polyD3MA, respectively, were prepared, endowing the polymers with the luminescence features of the nanoparticles. KW - Nanoparticles KW - Fluorides KW - Sol-gel process KW - Organic-inorganic hybrid composites PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508668 DO - https://doi.org/10.1002/cnma.202000058 SP - 1 EP - 11 PB - Wiley AN - OPUS4-50866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Wan, Wei A1 - Rurack, Knut T1 - Toward Label-Free Optical Multiplexing of Analytes in Indicator Release Lateral Flow Assays via Detection Zones Containing Tailored Capture Materials N2 - The use of macromolecules and materials immobilized in the detection zone of test strips for indicator capture and focusing in label-free lateral flow assays (LFAs) is described, with emphasis on its future use in low number multiplexing. Several materials such as polyelectrolytes, functionalized mesoporous silica micro- and nanoparticles, chemically modified cellulose or glass fibre (GF) membranes and molecularly imprinted polymer gels coated onto membranes were studied in model assays, before the most promising materials were combined with antibody-gated indicator delivering (gAID) sensor materials. Cellulose, nitrocellulose and GF membranes were used as supports and highly fluorescent dyes of different charge states as model indicators. Combination of the best performing capture materials with gAID systems made it possible to distinctly increase the sensitivity and reduce the measurement uncertainty in the LFA testing of pentaerythritol tetranitrate (PETN) in aqueous samples. In addition, dual-plexing of PETN and 2,4,6-trinitrotoluene (TNT) was realized on a single test strip containing two dedicated capture zones. KW - Rapid tests KW - Vor-Ort-Analytik KW - Multiplexing KW - Teststreifen KW - Molecularly imprinted polymers PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557873 DO - https://doi.org/10.1002/anse.202100062 VL - 2 IS - 4 SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-55787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karapanagiotis, Christos A1 - Schukar, Marcus A1 - Breithaupt, Mathias A1 - Hicke, Konstantin T1 - Toward a Digital Twin of Hydrogen Pressure Vessels Enabled by Distributed Fiber Optic Sensors N2 - We present a digital replica of a hydrogen pressure vessel enabled by distributed fiber optic sensors (DFOS). This digital replica dynamically displays and updates the vessel’s structural condition by calculating strain residuals defined as the difference between the measured DFOS strain and the expected strain based on pressure data. As an example, we show the ability of the DFOS to detect and localize damage caused by drilling six holes into the vessel’s body. This digital replica represents a foundational step toward a fully integrated digital twin for predictive maintenance and remaining lifetime prognosis. T2 - Sensor and Measurement Science International (SMSI) 2025 CY - Nuremberg, Germany DA - 06.05.2025 KW - fiber optic sensors KW - digital twin KW - structural health monitoring KW - hydrogen KW - machine learning PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633885 UR - https://www.ama-science.org/proceedings/details/5962 SN - 978-3-910600-06-5 DO - https://doi.org/10.5162/SMSI2025/C6.1 SP - 165 EP - 166 PB - AMA Service GmbH CY - Wunstorf AN - OPUS4-63388 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beygi Nasrabadi, Hossein A1 - Hanke, T. A1 - Weber, M. A1 - Eisenbart, M. A1 - Bauer, F. A1 - Meissner, R. A1 - Dziwis, G. A1 - Tikana, L. A1 - Chen, Yue A1 - Skrotzki, Birgit T1 - Toward a digital materials mechanical testing lab N2 - To accelerate the growth of Industry 4.0 technologies, the digitalization of mechanical testing laboratories as one of the main data-driven units of materials processing industries is introduced in this paper. The digital lab infrastructure consists of highly detailed and standard-compliant materials testing knowledge graphs for a wide range of mechanical testing processes, as well as some tools that enable the efficient ontology development and conversion of heterogeneous materials’ mechanical testing data to the machine-readable data of uniform and standardized structures. As a basis for designing such a digital lab, the mechanical testing ontology (MTO) was developed based on the ISO 23718 and ISO/IEC 21838-2 standards for the semantic representation of the mechanical testing experiments, quantities, artifacts, and report data. The trial digitalization of materials mechanical testing lab was successfully performed by utilizing the developed tools and knowledge graph of processes for converting the various experimental test data of heterogeneous structures, languages, and formats to standardized Resource Description Framework (RDF) data formats. The concepts of data storage and data sharing in data spaces were also introduced and SPARQL queries were utilized to evaluate how the introduced approach can result in the data retrieval and response to the competency questions. The proposed digital materials mechanical testing lab approach allows the industries to access lots of trustworthy and traceable mechanical testing data of other academic and industrial organizations, and subsequently organize various data-driven research for their faster and cheaper product development leading to a higher performance of products in engineering and ecological aspects. KW - General Engineering KW - General Computer Science PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582698 DO - https://doi.org/10.1016/j.compind.2023.104016 SN - 0166-3615 VL - 153 SP - 1 EP - 15 PB - Elsevier B.V. AN - OPUS4-58269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Halisch, M. A1 - Dlugosch, R. A1 - Prinz, Carsten T1 - Toward a better understanding of low-frequency electrical relaxation - An enhanced pore space characterization N2 - Relaxation phenomena observed in the electrical low-frequency range (approximately 1 mHz-10 kHz) of natural porous media like sandstones is often assumed to be directly related to the dominant (modal) pore throat sizes measured, for instance, with mercury intrusion porosimetry. Attempts to establish a universally valid relationship between pore size and peak Spectral Induced Polarization (SIP) relaxation time have failed, considering sandstones from very different origins and featuring great variations in textural and chemical compositions as well as in geometrical pore space properties. In addition working with characteristic relaxation times determined in Cole-Cole or Debye decomposition fits to build the relationship have not been successful. In particular, samples with narrow pore throats are often characterized by long SIP relaxation times corresponding to long “characteristic length scales” in these media, assuming that the diffusion coefficients along the electrical double layer were constant. Based on these observations, three different types of SIP relaxation can be distinguished. We present a new way of assessing complex pore spaces of very different sandstones in a multi-methodical approach to combine the benefits of mercury intrusion porosimetry, micro-computed tomography, and nuclear magnetic resonance. In this way, we achieve much deeper insight into the pore space due to the different resolutions and sensitivities of the applied methods to both pore constrictions (throats) and wide pores (pore bodies). We experimentally quantify pore aspect ratios and volume distributions within the two pore regions. We clearly observe systematic differences between three SIP relaxation types identified previously and can attribute the SIP peak relaxation times to measured characteristic length scales within our materials. We highlight selected results for a total of nine sandstones. It seems that SIP relaxation behavior depends on the size difference of the narrow pore throats to the wide pore bodies, which increases from SIP Type 1 to Type 3. KW - µ-CT KW - Spectral induced polarization KW - Nuclear magnetic resonance KW - Pore space PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509763 DO - https://doi.org/10.1190/GEO2019-0074.1 SN - 0016-8033 VL - 85 IS - 4 SP - MR257 EP - MR270 PB - Society of Exploration Geophysicists AN - OPUS4-50976 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lecompagnon, Julien A1 - Rooch, Ludwig A1 - Hassenstein, Christian A1 - Ziegler, Mathias ED - Sakagami, T. ED - Inoue, H. T1 - Total Focusing in the Virtual Wave Domain: 3D Defect Reconstruction Using Spatially Structured Laser Heating N2 - Classical active thermographic testing of industrial goods has mostly been limited to generating 2D defect maps. While for surface or near-surface defect detection, this is a desired result, for deeply buried defects, a 3D reconstruction of the defect geometry is coveted. This general trend can also be well observed in widely used NDT methods (radiography, ultrasonic testing), where the progression from 2D to 3D reconstruction methods has already made profound progress (CT, UT phased array transducers). Achieving a fully 3D defect reconstruction in active thermographic testing suffers from the diffusive nature of thermal processes. One possible solution to deal with thermal diffusion is the application of the virtual-wave concept, which, by solving an inverse problem, allows the diffusiveness to be extracted from the thermographic data in the post-processing stage. What is left follows propagating-wave physics, enabling the usage of well-known algorithms from ultrasonic testing. In this work, we present our progress in the 3D reconstruction of deeply buried defects using spatially structured laser heating in conjunction with applying the well-known total focusing method (TFM) in the virtual-wave domain. T2 - 18th International Workshop on Advanced Infrared Technology and Applications (AITA 2025) CY - Kobe, Japan DA - 15.09.2025 KW - Non-destructive testing KW - Virtual wave concept KW - Laser thermography KW - Thermal thomography PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641463 DO - https://doi.org/10.3390/proceedings2025129054 VL - 129 IS - 1 SP - 1 EP - 5 PB - MDPI CY - Basel AN - OPUS4-64146 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Van Tran, K. A1 - Woracek, R. A1 - Kardjilov, N. A1 - Markötter, Henning A1 - Abou-Ras, D. A1 - Puplampu, S. A1 - Förster, C. A1 - Penumadu, D. A1 - Dahlberg, C. F. O. A1 - Banhart, J. A1 - Manke, I. T1 - Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography N2 - Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale. KW - Neutron tomography KW - Phase distribution KW - Rectangular cross-section KW - Torsion KW - Geometrical effect PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561649 DO - https://doi.org/10.1016/j.matdes.2022.111037 SN - 0264-1275 VL - 222 SP - 111037 PB - Elsevier Ltd. AN - OPUS4-56164 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tran, K. V. A1 - Woracek, R. A1 - Kardjilov, N. A1 - Markötter, Henning A1 - Abou-Ras, D. A1 - Puplampu, S. A1 - Förster, C. A1 - Penumadu, D. A1 - Dahlberg, C. F. O. A1 - Banhart, J. A1 - Manke, I. T1 - Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography N2 - Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale. KW - Neutron tomography KW - Phase distribution KW - Rectangular cross-section KW - Torsion KW - Geometrical effect PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569101 DO - https://doi.org/10.1016/j.matdes.2022.111037 VL - 222 SP - 1 EP - 13 PB - Elsevier Ltd. AN - OPUS4-56910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Witte, Julien A1 - Schröpfer, Dirk A1 - Hamacher, M. A1 - Michels, H. A1 - Hamm, C. A1 - Appelt, M. A1 - Börner, Andreas A1 - Kannengießer, Thomas T1 - Tool development for hybrid finishing milling of iron aluminides N2 - The importance of high-temperature materials made of iron aluminides (FeAl) has been increasing in light weight applications, e.g., airplane turbines, due to the high material’s specific strength. However, the highly economic production by means of permanent mold casting involves special microstructures for Fe26Al4Mo0.5Ti1B alloy components leading to difficult machinability for subsequent finishing milling and low surface qualities. Major effects of tool and machining parameter variation incorporating ultrasonic assistance on the milling process and surface integrity are shown. Loads for tool and component surface are significantly adjustable to enable an economic process chain regarding the surface integrity of safety-relevant components. KW - Ultrasonic-assisted milling KW - Iron aluminide KW - Surface integrity KW - Tool wear PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566294 DO - https://doi.org/10.1016/j.procir.2022.03.123 SN - 2212-8271 VL - 108 SP - 793 EP - 798 PB - Elsevier B.V. AN - OPUS4-56629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dudziak, Mateusz A1 - Dural, Esra A1 - Dey, R. A1 - Ullrich, M. S. A1 - Huth, Christian A1 - Thomson, C. A1 - Schartel, Bernhard T1 - Together We Can: Synergistic Flame Retardancy by Melamine Polyphosphate and Phosphorylated Microalgae in Polylactide Biocomposites N2 - A strategy for enhancing the sustainable flame retardancy of polylactide (PLA) composites by partially replacing melamine polyphosphate (MPP), a commercial flame retardant proposed for PLA, with wastewater polyphosphate-enriched microalgae (P-Algae) has been explored. The incorporation of P-Algae at a 1:1 ratio with MPP leads to a notable synergistic effect, surpassing the expected additive behavior of the individual components. Comprehensive characterization encompassing thermogravimetric analysis coupled with FTIR, pyrolysis combustion flow calorimeter (PCFC), cone calorimeter, oxygen index (LOI), UL-94 tests, and rheological measurements—demonstrates that the presence of this biomaterial can significantly enhance flame retardant performance. Replacing 50% of MPP with P-Algae in PLA resulted in a 17% reduction in peak heat release rate (pHRR) and maintained a V-0 rating in UL-94 testing. The use of P-Algae does not compromise the flame retardancy of PLA but rather contributes positively, offering a promising path toward more sustainable flame-retardant systems. By leveraging naturally derived biomass, this approach aligns with the growing demand for novel eco-friendly technologies in polymer engineering. Insights into an innovative renewable additive as a functional and effective component in flame-retardant biocomposites have been achieved. KW - Flame retardancy KW - Melamine polyphosphate KW - Phosphorus- enriched microalgae KW - Polylactide PLA KW - Synergism PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640539 DO - https://doi.org/10.1002/pat.70350 SN - 1099-1581 SN - 1042-7147 VL - 36 IS - 9 SP - e70350 PB - John Wiley & Sons Ltd. AN - OPUS4-64053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scharek, Vera M. A1 - Pfeifer, Jens A1 - Vogl, Jochen A1 - Traub, Heike A1 - Meermann, Björn T1 - Tin fractionation analysis in sediment samples via on-line ID ETV/ICP-MS N2 - We report a quantification approach for directly determining total tin and tin-based pollutants/species in sediments via electrothermal vaporization/inductively coupled plasma-mass spectrometry (ETV/ICP-MS) utilizing an on-line isotope dilution mass spectrometry (IDMS) approach. The method was developed and validated using an estuarine sediment reference material (BCR-277R), yielding a recovery of 106%. A relative standard deviation (RSD) of 14%, comparable to published data using a similar method, was obtained. A limit of quantification (LOQ) was estimated at 0.008 mg Sn kg−1 and sufficient for quantifying the total tin mass fraction of surface sediments along the tidal River Elbe course. Hereby, a decrease towards the river mouth, presumably due to dilution effects by less polluted marine sediment, was observed. Besides total tin, monitoring of organotin compounds (OTCs)/species is of interest in sediments due to their toxic effects on aquatic life. The method’s capability was extended by separating an OTC fraction in a sediment certified reference material (CRM) through the ETV temperature program. While spiking experiments with OTC standards confirmed the assignment, only a small fraction of the total certified OTC amount (3%), likely due to matrix effects, was recovered. However, applying the method to real-world samples, OTCs were detectable along the River Elbe course. By this, we demonstrated the potential of our method as a complementary fast-screening approach to species-specific analysis procedures. KW - ETV KW - Sn-Speciation KW - Sediment PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640137 DO - https://doi.org/10.1007/s00216-025-06064-y SN - 1618-2642 SP - 1 EP - 10 PB - Springer Science and Business Media LLC AN - OPUS4-64013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Griesche, Axel A1 - Pfretzschner, B. A1 - Taparli, Ugur Alp A1 - Kardjilov, N. T1 - Time-Resolved Neutron Bragg-Edge Imaging: A Case Study by Observing Martensitic Phase Formation in Low Temperature Transformation (LTT) Steel during GTAW N2 - Polychromatic and wavelength-selective neutron transmission radiography were applied during bead-on-plate welding on 5 mm thick sheets on the face side of martensitic low transformation temperature (LTT) steel plates using gas tungsten arc welding (GTAW). The in situ visualization of austenitization upon welding and subsequent α’-martensite formation during cooling could be achieved with a temporal resolution of 2 s for monochromatic imaging using a single neutron wavelength and of 0.5 s for polychromatic imaging using the full spectrum of the beam (white beam). The spatial resolution achieved in the experiments was approximately 200 µm. The transmitted monochromatic neutron beam intensity at a wavelength of λ = 0.395 nm was significantly reduced during cooling below the martensitic start temperature Ms since the emerging martensitic phase has a ~10% higher attenuation coefficient than the austenitic phase. Neutron imaging was significantly influenced by coherent neutron scattering caused by the thermal motion of the crystal lattice (Debye–Waller factor), resulting in a reduction in the neutron transmission by approx. 15% for monochromatic and by approx. 4% for polychromatic imaging. KW - Austenite-to-martensite transformation KW - Neutron radiography KW - Bragg-edge imaging KW - Gas tungsten arc welding (GTAW) KW - Debye–Waller factor KW - Low transformation temperature (LTT) steel PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538016 DO - https://doi.org/10.3390/app112210886 VL - 11 IS - 22 SP - 10886 PB - MDPI CY - Basel AN - OPUS4-53801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Griesche, Axel A1 - Pfretzschner, Beate A1 - Taparli, Ugur Alp A1 - Kardjilov, N. T1 - Time-Resolved Neutron Bragg-Edge Imaging: A Case Study by Observing Martensitic Phase Formation in Low Temperature Transformation (LTT) Steel during GTAW N2 - Polychromatic and wavelength-selective neutron transmission radiography were applied during bead-on-plate welding on 5 mm thick sheets on the face side of martensitic low transformation temperature (LTT) steel plates using gas tungsten arc welding (GTAW). The in situ visualization of austenitization upon welding and subsequent α’-martensite formation during cooling could be achieved with a temporal resolution of 2 s for monochromatic imaging using a single neutron wavelength and of 0.5 s for polychromatic imaging using the full spectrum of the beam (white beam). The spatial resolution achieved in the experiments was approximately 200 µm. The transmitted monochromatic neutron beam intensity at a wavelength of λ = 0.395 nm was significantly reduced during cooling below the martensitic start temperature M s since the emerging martensitic phase has a ~10% higher attenuation coefficient than the austenitic phase. Neutron imaging was significantly influenced by coherent neutron scattering caused by the thermal motion of the crystal lattice (Debye–Waller factor), resulting in a reduction in the neutron transmission by approx. 15% for monochromatic and by approx. 4% for polychromatic imaging. KW - Neutron radiography KW - Debye–Waller factor KW - Austenite-to-martensite transformation KW - Low transformation temperature (LTT) steel KW - Bragg-edge imaging KW - Gas tungsten arc welding (GTAW) PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559077 DO - https://doi.org/10.3390/app112210886 VL - 11 IS - 22 PB - MDPI AN - OPUS4-55907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kabelitz, Anke A1 - de Oliveira Guilherme Buzanich, Ana A1 - Joester, Maike A1 - Reinholz, Uwe A1 - Radtke, Martin A1 - Bienert, Ralf A1 - Schulz, K. A1 - Schmack, R. A1 - Kraehnert, R. A1 - Emmerling, Franziska T1 - Time-resolved in situ studies on the formation mechanism of iron oxide nanoparticles using combined fast-XANES and SAXS N2 - The reaction of iron chlorides with an alkaline reagent is one of the most prominent methods for the synthesis of iron oxide nanoparticles. We studied the particle formation mechanism using triethanolamine as reactant and stabilizing agent. In situ fast-X-ray absorption near edge spectroscopy and small-angle X-ray scattering provide information on the oxidation state and the structural information at the same time. In situ data were complemented by ex situ transmission electron microscopy, wide-angle X-ray scattering and Raman analysis of the formed nanoparticles. The formation of maghemite nanoparticles (γ-Fe2O3) from ferric and ferrous chloride was investigated. Prior to the formation of these nanoparticles, the formation and conversion of intermediate phases (akaganeite, iron(II, III) hydroxides) was observed which undergoes a morphological and structural collapse. The thus formed small magnetite nanoparticles (Fe3O4) grow further and convert to maghemite with increasing reaction time. KW - oxidation state KW - structural information KW - maghemite PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351376 DO - https://doi.org/10.1039/C5CE01585E SN - 1466-8033 VL - 17 IS - 44 SP - 8463 EP - 8470 CY - London, UK AN - OPUS4-35137 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karapanagiotis, Christos A1 - Wosniok, Aleksander A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Time-Efficient Convolutional Neural Network-Assisted Brillouin Optical Frequency Domain Analysis N2 - To our knowledge, this is the first report on a machine-learning-assisted Brillouin optical frequency domain analysis (BOFDA) for time-efficient temperature measurements. We propose a convolutional neural network (CNN)-based signal post-processing method that, compared to the conventional Lorentzian curve fitting approach, facilitates temperature extraction. Due to its robustness against noise, it can enhance the performance of the system. The CNN-assisted BOFDA is expected to shorten the measurement time by more than nine times and open the way for applications, where faster monitoring is essential. KW - Fiber-optic sensors KW - Machine learning KW - Temperature and strain monitoring KW - Brillouin distributed sensing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524631 DO - https://doi.org/10.3390/s21082724 VL - 21 IS - 8 SP - 2724 PB - MDPI AN - OPUS4-52463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Örnek, C. A1 - Léonard, Fabien A1 - McDonald, S. A1 - Prajapati, A A1 - Withers, P. J. A1 - Engelberg, D. T1 - Time-dependent in situ measurement of atmospheric corrosion rates of duplex stainless steel wires N2 - Corrosion rates of strained grade UNS S32202 (2202) and UNS S32205 (2205) duplex stainless steel wires have been measured, in situ, using time-lapse X-ray computed tomography. Exposures to chloride-containing (MgCl2) atmospheric environments at 50 °C (12–15 M Cl− and pH ~5) with different mechanical elastic and elastic/plastic loads were carried out over a period of 21 months. The corrosion rates for grade 2202 increased over time, showing selective dissolution with shallow corrosion sites, coalescing along the surface of the wire. Corrosion rates of grade 2205 decreased over time, showing both selective and pitting corrosion with more localised attack, growing preferentially in depth. The nucleation of stress corrosion cracking was observed in both wires. KW - X-ray computed tomography KW - Time-lapse X-ray computed tomography PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444153 UR - https://www.nature.com/articles/s41529-018-0030-9 DO - https://doi.org/10.1038/s41529-018-0030-9 SN - 2397-2106 VL - 2 SP - Article 10, 1 EP - 15 PB - Nature CY - London AN - OPUS4-44415 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Peters, Stefan A1 - Kunkel, Benny A1 - Cakir, Cafer Tufan A1 - Kabelitz, Anke A1 - Witte, Steffen A1 - Bernstein, Thomas A1 - Bartling, Stephan A1 - Radtke, Martin A1 - Emmerling, Franziska A1 - Abdel-Mageed, Ali Mohamed A1 - Wohlrab, Sebastian A1 - de Oliveira Guilherme Buzanich, Ana T1 - Time-, space- and energy-resolved in situ characterization of catalysts by X-ray absorption spectroscopy N2 - A novel setup for dispersive X-ray absorption spectroscopy (XAS) with simultaneous resolution of space, time and energy for in situ characterization of solid materials is demonstrated. KW - Dispersive XAS KW - Catalysis KW - In situ KW - Structure analysis PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584924 DO - https://doi.org/10.1039/d3cc03277a SN - 1359-7345 SP - 1 EP - 4 PB - Royal Society of Chemistry (RSC) AN - OPUS4-58492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Emmerling, Franziska T1 - Time- & spatial-resolved X-ray absorption fine structure (XAFS) spectroscopy in a single-shot – new analytical possibilities for in situ material characterization N2 - A new concept that comprises both time- and lateral-resolved X-ray absorption fine-structure information simultaneously in a single shot is presented. This uncomplicated set-up was tested at the BAMline at BESSY-II (Berlin, Germany). The primary broadband beam was generated by a double multilayer monochromator. The transmitted beam through the sample is diffracted by a convexly bent Si (111) crystal, producing a divergent beam. This, in turn, is collected by either an energy-sensitive area detector, the so-called color X-ray camera, or by an area-sensitive detector based on a CCD camera, in θ-2θ geometry. The first tests were performed with thin metal foils and some iron oxide mixtures. A time resolution of lower than 1 s together with a spatial resolution in one dimension of at least 50 µm is achieved. KW - Time resolution KW - Single-shot XAFS PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370892 DO - https://doi.org/10.1107/S1600577516003969 SN - 1600-5775 IS - 23 SP - 769 EP - 776 PB - International Union of Crystallography CY - Chester, UK AN - OPUS4-37089 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spranger, Holger A1 - Beckmann, Jörg A1 - Boehm, Rainer T1 - THz-ToF techniques for the detection of inherent discontinuities in dielectric materials based on a SAFT – and an optical layer reconstruction algorithm N2 - Electromagnetic waves with frequencies between 0.1 and 10 THz are described as THz-radiation (T-ray). The ability to penetrate dielectric materials makes T-rays attractive to reveal discontinuities in polymer and ceramic materials. THz-Time Domain Spectroscopy Systems (THz-TDS) are available on the market today which operates with THz-pulses transmitted and received by optically pumped semiconductor antennas. In THz-TDS the travelling time (ToF) and shape of the pulse is changed if it interacts with the dielectric material and its inherent discontinuities. A tomogram of the object under the test can be reconstructed from time of flight diffraction (ToFD) scans if a synthetic focusing aperture (SAFT) algorithm is applied. Otherwise, planar discontinuities like cracks in plastics or delaminated layers in composites can be abstracted as layers located at any angle in relation to the outer sample surface direction. A tomogram from the scanned sample can then be reconstructed in case the interactions of electromagnetic pulses with the existing inherent interfaces are detectable and a model is assumed which describes the device under the test as multilayer structure composed of thin layers with different dielectric properties. A short description of both the SAFT – and Optical Layer algorithm for the reconstruction of the inherent structure is initially given. Measurements on representative samples with a variety of artificially produced small and large scale. Reconstructed tomograms are presented to discuss and evaluate the benefits and limits of the two different reconstruction approaches. T2 - 19th World Conference on Non-Destructive Testing 2016 CY - Munich, Germany DA - 13.06.2016 KW - THz SAFT Optical layer reconstruction PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365866 SN - 978-3-940283-78-8 VL - 158 SP - 1 EP - 10 AN - OPUS4-36586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - Grelle, Tobias A1 - Jaunich, Matthias A1 - Goral, Milan A1 - Wolff, Dietmar T1 - Three-dimensional thermal expansion of neat and irradiated (U)HMWPE materials at elevated temperatures N2 - The thermal expansion of polymeric parts can be an issue in many applications where the available space is limited, or exact dimensions of the part are required. For this study, a device was designed and built that allowed measuring the thermal expansion simultaneously in all three spatial directions on cubic samples with real-scale dimensions (78 mm edge length). The results are shown between 25 °C and 125 °C for two PE materials, one HMWPE and one tempered UHMWPE, for non-irradiated samples as well as cubes that have been irradiated with 100 and 400 kGy. The results measured with the new device were very similar to those measured with conventional thermo-mechanical analysis equipment and to literature data of UHMWPE. The HMWPE material shows a much larger thermal expansion coefficient in one direction compared to the other two directions during the first heating due to frozen stresses from the pressing step during material manufacturing. These stresses are mostly released by the expansion during the first heating, so that the expansion during the second heating is more uniform. The overall volumetric expansion is the same for both heating runs. By contrast, the tempered UHMWPE material shows no significant difference between first and second heating run, as the stresses from processing could already relax in the tempering step. The irradiation treatment does not affect the values significantly for the given test set-up. KW - Lupolen KW - Ultra high molecular weight polyethylene KW - GUR KW - Coefficient of thermal expansion KW - High temperature PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563987 DO - https://doi.org/10.1016/j.polymertesting.2022.107841 SN - 0142-9418 VL - 117 SP - 1 EP - 8 PB - Elsevier Ltd. AN - OPUS4-56398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Manke, I. A1 - Kardjilov, N. A1 - Schäfer, R. A1 - Hilger, A. A1 - Grothausmann, R. A1 - Strobl, M. A1 - Dawson, M. A1 - Grünzweig, C. A1 - Tötzke, C. A1 - David, C. A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Banhart, J. T1 - Three-dimensional imaging of magnetic domains with neutron grating interferometry N2 - This paper gives a brief overview on3D imaging of magnetic domains with shearing grating neutron tomography. We investigated the three-dimensional distribution of magnetic domain walls in the bulk of a wedge-shaped FeSi single crystal. The width of the magnetic domains wasanalyzed at different locations within the crystal. Magnetic domains close to the tip of the wedge are much smaller than in the bulk. Furthermore, the three-dimensional shape of individual domains wasinvestigated. We discuss prospects and limitations of the applied measurement technique. KW - Neutron imaging KW - Tomography KW - Magnetic domains KW - Grating interferometry KW - Darkfield imaging KW - Shearing gratings KW - Talbot-Lau KW - Three-dimensional data quantification KW - Tomographic reconstruction PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-341919 DO - https://doi.org/10.1016/j.phpro.2015.07.057 SN - 1875-3892 VL - 69 SP - 404 EP - 412 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-34191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - De la Hoz Alford, L. A1 - Pecanha de Souza, C. G. A1 - Paciornik, S. A1 - d` Almeida, J. R. M. A1 - Santos Leite, B. A1 - Avila, H. C. A1 - Léonard, F. A1 - Bruno, Giovanni T1 - Three-Dimensional Characterization of Polyurethane Foams Based on Biopolyols N2 - Two biopolyol-based foams derived from banana leaves (BL) or stems (BS) were produced, and their compression mechanical behavior and 3D microstructure were characterized. Traditional compression and in situ tests were performed during 3D image acquisition using X-ray microtomography. A methodology of image acquisition, processing, and analysis was developed to discriminate the foam cells and measure their numbers, volumes, and shapes along with the compression steps. The two foams had similar compression behaviors, but the average cell volume was five times larger for the BS foam than the BL foam. It was also shown that the number of cells increased with increasing compression while the average cell volume decreased. Cell shapes were elongated and did not change with compression. A possible explanation for these characteristics was proposed based on the possibility of cell collapse. The developed methodology will facilitate a broader study of biopolyol-based foams intending to verify the possibility of using these foams as green alternatives to the typical petrol-based foams. KW - Compression mechanical KW - Biopolyol KW - Banana KW - 3D microstructure KW - X-ray microtomography PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571982 DO - https://doi.org/10.3390/ma16052118 SN - 1996-1944 VL - 16 IS - 5 SP - 1 EP - 12 PB - MDPI CY - Basel AN - OPUS4-57198 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kotschate, Daniel A1 - Gohlke, Dirk A1 - Heckel, Thomas T1 - Three dimensional examination of directivity pattern in immersion tank testing N2 - High resolution examination of safety-relevant parts in immersion tank testing with focussing probes is forming a main topic of modern non-destructive testing. For the usage of complex reconstruction methods and algorithms, an individual and detailed knowledge about the transmission behaviour of the used probes is essential, as this has a significant influence on the results of data reconstruction. Especially the knowledge about position and diameter of the focal point is needed to achieve the highest possible sensitivity. Through the individual position of the beam axis within the examined volume, a four dimensional metro logical determination of the acoustical pressure (x, y, z, t) is necessary. With the measured data it is possible to draw interferences about the sound field and acoustical pressure distribution. The presented work realized a method of automatic determination of the beam axis, the position of focal point and the focal diameter to support individual testing setups and transducer characterization. T2 - 7th International Symposium on NDT in Aerospace CY - Bremen, Germany DA - 16.11.2015 PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-339995 AN - OPUS4-33999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wagner, Jan A1 - Dudziak, Mateusz A1 - Falkenhagen, Jana A1 - Rockel, Daniel A1 - Reimann, H.-A A1 - Schartel, Bernhard T1 - This is the way: An evidence based route to phytic-acid–based flame retardant poly(lactide acid) N2 - A systematic sequence of materials was investigated to develop phytic-acid (Phyt)–based flame retarded poly (lactide acid) (PLA), while factoring in molecular weight (MW), crystallinity and mechanical properties. Synergistic approaches were developed based on combinations with lignin and expandable graphite (EG), as well as by applying different Phyt salts of melamine (Mel), piperazine (Pip), and arginine (Arg). Compounds were twin screw extruded, injection molded, hot pressed and investigated with thermal analysis, size exclusion chromatography, infrared spectroscopy, tensile testing, limited oxygen index (LOI), UL 94, cone calorimeter, and scanning electron microscope. 16.7 wt.% flame retardant (FR) slightly enhances crystallization while MW remains unchanged in PLA Phyt Arg and PLA Phyt Mel. LOI was improved to 43.7 vol.% for PLA Phyt Arg, UL 94 V0 achieved for PLA Phyt Pip. Cone calorimeter results show total heat evolved reduced by 14 %, maximum average rate of heat emission 43 % lower, and peak heat release rate reduced by 50 % for PLA Phyt Mel. Phyt Mel combined with EG increased the char yield of PLA to 20 wt.% and 15.5 wt.% at 600 and 900 ◦C, respectively. Phyt is exploited to enhance char yield, stabilize the intumescent char, and lower the apparent effective heat of combustion. The combination of Phyt Mel and EG was proposed as an efficient FR for PLA via an evidence based developing route. KW - Polylactide acid KW - Intumescent flame retardant KW - Phosphorous flame retardant KW - Phytic acid KW - Expandable graphite KW - Melamine PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626395 DO - https://doi.org/10.1016/j.polymdegradstab.2025.111242 SN - 1873-2321 SN - 0141-3910 VL - 234 SP - 1 EP - 14 PB - Elsevier Ltd. AN - OPUS4-62639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Valderrey, Virginia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Thiourea- and Amino-Substituted Benzoxadiazole Dyes with Large Stokes Shifts as Red-Emitting Probe Monomers for Imprinted Polymer Layers Targeting Carboxylate-Containing Antibiotics N2 - Bifunctional fluorescent molecular oxoanion probes based on the benzoxadiazole (BD) chromophore are described which integrate a thiourea binding motif and a polymerizable 2-aminoethyl methacrylate unit in the 4,7-positions of the BD core. Concerted charge transfer in this electron donor-acceptor-donor architecture endows the dyes with strongly Stokes shifted (up to >250 nm) absorption and fluorescence. Binding of electron-rich carboxylate guests at the thiourea receptor leads to further analyte-induced red-shifts of the emission, shifting the fluorescence maximum of the complexes to ≥700 nm. Association constants for acetate are ranging from 1–5×105 M−1 in acetonitrile. Integration of one of the fluorescent probes through its polymerizable moiety into molecularly imprinted polymers (MIPs) grafted from the surface of submicron silica cores yielded fluorescent MIP-coated particle probes for the selective detection of antibiotics containing aliphatic carboxylate groups such as enoxacin (ENOX) at micromolar concentrations in highly polar solvents like acetonitrile. KW - Molecular imprinting KW - Anion recognition KW - Antibiotics KW - Benzoxadiazole dyes KW - Charge transfer KW - Fluorescence PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545027 DO - https://doi.org/10.1002/chem.202104525 SN - 1521-3765 SP - 1 EP - 9 PB - Wiley-VCH AN - OPUS4-54502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silbernagl, Dorothee A1 - Sturm, Heinz A1 - Plajer, A. J. T1 - Thioanhydride/isothiocyanate/epoxide ring-opening terpolymerisation: sequence selective enchainment of monomer mixtures and switchable catalysis N2 - We report a new sequence selective terpolymerisation in which three monomers (butylene oxide (BO) A, PhNCS B and phtalic thioanhydride (PTA) C) are selectively enchained into an (ABA′C)n sequence. PTA/PhNCS/BO ring-opening terpolymerisation ROTERP can be coupled with CS2 ROTERP to generate tetrapolymers and with εDL ROP in switchable catalysis for blockpolymer synthesis. KW - Blockcopolymer KW - 1H-NMR KW - TGA KW - DSC KW - AFM PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552339 DO - https://doi.org/10.1039/d2py00629d SP - 1 EP - 5 PB - Royal Society of Chemistry CY - Cambridge, UK AN - OPUS4-55233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yu, C.-H. A1 - Peng, R. L. A1 - Luzin, V. A1 - Sprengel, Maximilian A1 - Calmunger, M. A1 - Lundgren, J.-E. A1 - Brodin, H. A1 - Kromm, Arne A1 - Moverare, J. T1 - Thin-wall effects and anisotropic deformation mechanisms of an additively manufactured Ni-based superalloy N2 - Laser powder bed fusion (LPBF) of Ni-based superalloys shows great potential for high temperature applications, for example, as a burner repair application for gas turbines where the thin-walled structure is important. It motivates this work to investigate the evolution of microstructure and the anisotropic mechanical behavior when plate-like specimens are built with a thickness from 4 mm down to 1 mm. By performing texture analysis using neutron diffraction, a clear transition in fiber texture from <011> to <001> is indicated when the specimen becomes thinner. The residual stress shows no thickness dependence, and at the subsurface the residual stress reaches the same level as the yield strength. Due to the rough as-built surface, a roughness compensation method for mechanical properties of thin-walled structures is outlined and demonstrated. Tensile tests from room temperature up to 700 ◦C have been carried out. Anisotropic mechanical behavior is found at all temperatures, which is strongly related to the anisotropic texture evolution. Stronger texture evolution and grain rotations are discovered when the tensile loading is applied along the building direction. The mechanical behavior has been compared to a wrought material, where the high dislocation density and the subgrain structure of the LPBF material result in a higher yield strength. Combining the statistical texture analysis by neutron diffraction with mechanical testing, EBSD grain orientation mapping and the investigation of dislocation structures using transmission electron microscopy, this work illustrates the significance of texture for the thin-wall effect and anisotropic mechanical behavior of LPBF materials. KW - Hastelloy X KW - Hot tensile test KW - Crystallographic texture KW - Roughness KW - Residual stress KW - Dislocation density PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518759 DO - https://doi.org/10.1016/j.addma.2020.101672 VL - 36 SP - 101672 PB - Elsevier B.V. AN - OPUS4-51875 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lanzino, Maria Carolina A1 - Le, Long-Quan R. V. A1 - Wilbig, Janka A1 - Rheinheimer, Wolfgang A1 - Seidenstuecker, Michael A1 - Günster, Jens A1 - Killinger, Andreas T1 - Thin GB14 coatings on implants using HVSFS N2 - Enhancing osseointegration, the process by which medical implants securely bond to bone, is crucial for improving patient outcomes in orthopedics and dental surgery. Calcium alkali orthophosphates, with their superior bioactivity, resorbability, and chemical resemblance to bone minerals, have emerged as promising candidates for implant coatings. These materials offer improved solubility and lower melting points due to the substitution of calcium with potassium and sodium, along with the addition of magnesium oxide. This study investigates GB14 calcium alkali orthophosphate coatings applied via High Velocity Suspension Flame Spraying (HVSFS), a technique that enables precise control over coating properties. A porosity target of &gt;10% was set to promote bone growth, and we achieved porosities up to 13%, ensuring better cell penetration and stability at the implant-bone interface. Coatings were produced using different gas parameters and distances, with their microstructure and phase composition analyzed using scanning electron microscope (SEM), Vickers hardness testing and X-ray diffraction (XRD). Additionally, roughness and porosity were also assessed. Different coating’s microstructures were achieved by varying stand-off distance and gas parameters. Increasing stand-off distance while reducing gas stoichiometry enabled the production of calcium alkali orthophosphate coatings with fewer cracks, higher porosity and a hardness level comparable to that of state-of-the-art tricalcium phosphate (TCP) coatings. The sample with optimized properties in terms of achieved microstructure and topography was selected for in vitro testing using MG63 osteosarcoma cells to evaluate cell proliferation and adhesion. WST (I) assay, LDH assay, and live/dead staining confirmed the biocompatibility of the coatings, highlighting the potential of HVSFS to enhance osseointegration and outperform conventional methods in implantology. No relevant cytotoxicity could be shown and cells show a good proliferation over time. These results highlight thus the potential of HVSFS to produce thin, bioactive and resorbable coatings to enhance osseointegration. KW - Bio ceramics KW - Spray coating PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623983 DO - https://doi.org/10.3389/fmats.2024.1522447 SN - 2296-8016 VL - 11 IS - 1522447 SP - 1 EP - 14 PB - Frontiers Media SA AN - OPUS4-62398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rhode, Michael A1 - Richter, Tim A1 - Mente, Tobias A1 - Mayr, P. A1 - Nitsche, A. T1 - Thickness and microstructure effect on hydrogen diffusion in creep‑resistant 9% Cr P92 steel and P91 weld metal N2 - Martensitic 9% Cr steels like P91 and P92 show susceptibility to delayed hydrogen assisted cracking depending on their microstructure. In that connection, effective hydrogen diffusion coefficients are used to assess the possible time-delay. Limited data on room temperature diffusion coefficients reported in literature vary widely by several orders of magnitude (mostly attributed to variation in microstructure). Especially P91 weld metal diffusion coefficients are rare so far. For that reason, electrochemical permeation experiments had been conducted using P92 base metal and P91 weld metal (in as-welded and heat-treated condition) with different thicknesses. From the results obtained, diffusion coefficients were calculated using to different methods, time-lag, and inflection point. Results show that, despite microstructural effects, the sample thickness must be considered as it influences the calculated diffusion coefficients. Finally, the comparison of calculated and measured hydrogen concentrations (determined by carrier gas hot extraction) enables the identification of realistic diffusion coefficients. KW - Creep-resistant steel KW - Diffusion KW - Hydrogen assisted cracking KW - Welding KW - Electrochemical permeation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540645 DO - https://doi.org/10.1007/s40194-021-01218-9 SN - 0043-2288 SP - 1 EP - 16 PB - Springer Nature Switzerland AG AN - OPUS4-54064 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Häusler, Ines A1 - Darvishi Kamachali, Reza A1 - Hetaba, W. A1 - Skrotzki, Birgit T1 - Thickening of T-1 Precipitates during Aging of a High Purity Al–4Cu–1Li–0.25Mn Alloy N2 - The age hardening response of a high-purity Al–4Cu–1Li–0.25Mn alloy (wt. %) during isothermal aging without and with an applied external load was investigated. Plate shaped nanometer size T1 (Al2CuLi) and θ′ (Al2Cu) hardening phases were formed. The precipitates were analyzed with respect to the development of their structure, size, number density, volume fraction and associated transformation strains by conducting transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) studies in combination with geometrical Phase analysis (GPA). Special attention was paid to the thickening of T1 phase. Two elementary types of single-layer T1 precipitate, one with a Li-rich (Type 1) and another with an Al-rich (Defect Type 1) central layer, were identified. The results show that the Defect Type 1 structure can act as a precursor for the Type 1 structure. The thickening of T1 precipitates occurs by alternative stacking of These two elementary structures. The thickening mechanism was analyzed based on the magnitude of strain associated with the precipitation transformation normal to its habit plane. Long-term aging and aging under load resulted in thicker and structurally defected T1 precipitates. Several types of defected precipitates were characterized and discussed. For θ′ precipitates, a ledge mechanism of thickening was observed. Compared to the normal aging, an external load applied to the peak aged state leads to small variations in the average sizes and volume fractions of the precipitates. KW - Al-Cu-Li-alloy KW - Precipitation KW - T1 precipitate KW - Microstructure evolution KW - Thickening KW - Creep KW - Volume fraction KW - Number density KW - Strain difference PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471207 DO - https://doi.org/10.3390/ma12010030 SN - 1996-1944 VL - 12 IS - 1 SP - 30, 1 EP - 23 PB - MDPI AN - OPUS4-47120 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chaudhuri, Somsubhro A1 - Purayil, Sruthi Krishna Kunji A1 - Kruse, Julius A1 - Madia, Mauro A1 - Nielsen, Sören T1 - Thermography-Assisted Mechanical Testing of Cold-Spray (AM) Repair N2 - Cold Spray Additive Manufacturing (CSAM) is a solid-state process that is being increasingly used for structural repairs in aerospace and energy sectors. It enables the deposition of dense material at low temperatures by accelerating metal particles to supersonic velocities, thereby reducing thermal distortion. However, the structural integrity of CSAM repairs—particularly at the interface between the deposited layer and the substrate—remains a critical concern. Various post-treatments and characterization methods have been explored to optimize performance. While X-ray Computed Tomography (XCT) is effective for sub-surface inspection, it cannot be applied in situ during mechanical testing. Digital Image Correlation (DIC), a surface-based method, also lacks sub-surface sensitivity. To address this, Infrared Thermography (IRT) was employed alongside DIC during the tensile and fatigue testing of aluminum CSAM-repaired specimens. A cooled IRT camera operating at 200 FPS captured thermal data, with lock-in processing subsequently applied in post-processing. IRT successfully detected early interfacial damage and enabled the tracking of crack propagation, which was later confirmed through fracture surface analysis. This extended abstract presents findings from fatigue tests using IRT. T2 - 18th International Workshop on Advanced Infrared Technology and Applications (AITA 2025) CY - Kobe, Japan DA - 15.09.2025 KW - Thermography KW - Thermografie KW - Thermal stress analysis KW - Cold spray KW - Damage detection PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642299 DO - https://doi.org/10.3390/proceedings2025129018 VL - 129 IS - 1 SP - 1 EP - 5 PB - MDPI CY - Basel AN - OPUS4-64229 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krankenhagen, Rainer A1 - Röllig, Mathias A1 - Worzewski, Tamara A1 - Doroshtnasir, Manoucher T1 - Thermographic rotor blade inspection from larger distances – a promising tool for the maintenance of wind turbines N2 - The permanently increasing number of wind turbines requires suited inspection and monitoring methods to ensure liability and security. Concerning the inspection of ro-tor blades, only manual inspections are state of the art. Thermographic Testing (TT) has the potential to detect typical failures and damages on rotor blades. The paper presents some results of onsite measurements carried out as “passive thermogra-phy”, i.e. without a defined heating procedure. Due the totally contactless meas-urement principle, TT can be applied to rotating blades as well as to resting blades. Both methods will be compared with respect to their possible realization. T2 - WCNDT 2016 CY - Munich, Germany DA - 13.06.2016 KW - Wind turbine rotor blade KW - Thermographic inspection KW - Passive thermography KW - Nondestructive testing PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366331 SN - 978-3-940283-78-8 SP - We.4.D.4., 1 EP - 8 AN - OPUS4-36633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lecompagnon, Julien A1 - Ahmadi, Samim A1 - Hirsch, Philipp Daniel A1 - Rupprecht, C. A1 - Ziegler, Mathias T1 - Thermographic detection of internal defects using 2D photothermal super resolution reconstruction with sequential laser heating N2 - Thermographic photothermal super resolution reconstruction enables the resolution of internal defects/inhomogeneities below the classical limit, which is governed by the diffusion properties of thermal wave propagation. Based on a combination of the application of special sampling strategies and a subsequent numerical optimization step in post-processing, thermographic super resolution has already proven to be superior to standard thermographic methods in the detection of one-dimensional defect/inhomogeneity structures. In our work, we report an extension of the capabilities of the method for efficient detection and resolution of defect cross sections with fully two-dimensional structured laser-based heating. The reconstruction is carried out using one of two different algorithms that are proposed within this work. Both algorithms utilize the combination of several coherent measurements using convex optimization and exploit the sparse nature of defects/inhomogeneities as is typical for most nondestructive testing scenarios. Finally, the performance of each algorithm is rated on reconstruction quality and algorithmic complexity. The presented experimental approach is based on repeated spatially structured heating by a high power laser. As a result, a two-dimensional sparse defect/inhomogeneity map can be obtained. In addition, the obtained results are compared with those of conventional thermographic inspection methods that make use of homogeneous illumination. Due to the sparse nature of the reconstructed defect/inhomogeneity map, this comparison is performed qualitatively. KW - Thermography KW - Super resolution KW - NDT KW - Inspection KW - Internal defects PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548351 DO - https://doi.org/10.1063/5.0088102 SN - 1089-7550 VL - 131 IS - 18 SP - 1 EP - 12 PB - AIP Publishing AN - OPUS4-54835 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unnikrishnakurup, Sreedhar A1 - Myrach, Philipp A1 - Polomski, Benjamin A1 - Le Claire, Elisabeth A1 - Vengara, N. A1 - Balasubramaniam, Krishnan A1 - Ziegler, Mathias T1 - Thermographic crack detection in hot steel surfaces N2 - The detection and characterization of surface cracks in steel specimens prior to damage is a technologically and economically highly significant task and is of utmost importance when it comes to safety-relevant structures. In steel production where steel billets at high temperatures have to be inspected while moving a number of well-established NDT methods cannot be applied. Laser thermography however is a promising candidate to serve as a fast, non-contact and remote tool in this case. We present a study that shows that the crack detection capabilities of laser thermography can be extended also to specimens at high temperature. A combination of inductive and laser heating allows to systematically study the contrast formation as well as the optimization of the important measurement parameters. The experiments are accompanied by FEM simulations that provide a better insight of the physical correlations and support the experimental developments. The aim of these studies is to develop a system with high inspection speed and detection performance to be in-line operated under the hostile environment of steel production lines. T2 - 19th World Conference on Non-Destructive Testing (WCNDT 2016) CY - Munich, Germany DA - 13.06.2016 KW - In-line Monitoring KW - Laser Infrared thermography KW - Cracks KW - Induction heating KW - Steel billets KW - FEM simulation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389161 UR - http://ndt.net/?id=19573 SN - 1435-4934 VL - 21 IS - 7 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-38916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ikeda, Yuki A1 - Wallis, Theophilus A1 - Maaß, Robert A1 - Darvishi Kamachali, Reza T1 - Thermodynamics of grain boundary segregation transition and their relevance for liquid metal embrittlement in Fe-Zn system N2 - Grain boundaries (GBs) are common sites of failure in polycrystalline materials. Recently, a massive Zn segregation transition at Fe GBs was discovered and shown to act as a potent precursor of liquid metal embrittlement (LME) in the Fe-Zn system (Kamachali et al., Scripta Materialia 238 (2024) 115758). In this study, we elaborate on how temperature, GB type and the chemo-structurally coupled phase decomposition at the GB impact this segregation transition. CALPHAD and atomistic simulation data were utilized as inputs to conduct quantitative density-based thermodynamic modeling and phase-field simulations across various GBs, alloy compositions, and temperatures. We reveal that once the segregation transition becomes possible, the GB structural variation stabilizes spinodally formed Zn-rich phases within the GB region, with a higher tendency in disordered GBs. GB phase diagrams were constructed to identify and analyze the range of critical temperatures and alloy compositions associated with the segregation transition. The phase diagrams reveal that the miscibility gap for more disordered GB expands and, although the segregation transition is inevitable and occurs for all GBs, the barrier to triggering it is lower for more disordered GBs. Based on our thermodynamic analyses, potential processing modifications and GB engineering strategies for mitigating segregation-induced LME are thoroughly discussed. KW - Thermodynamics KW - Phase-Field Modelling KW - Steels PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634145 DO - https://doi.org/10.1016/j.actamat.2025.121134 SN - 1359-6454 VL - 296 SP - 1 EP - 11 PB - Elsevier BV AN - OPUS4-63414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Herzel, Hannes A1 - Grevel, K.-D. A1 - Emmerling, Franziska A1 - Dachs, E. A1 - Benisek, A. A1 - Adam, Christian A1 - Majzlan, J. T1 - Thermodynamic properties of calcium alkali phosphates Ca(Na,K)PO4 N2 - Calcium alkali phosphates Ca(Na,K)PO4 are main constituents of bioceramics and thermochemically produced phosphorus fertilizers because of their bioavailability. Sparse thermodynamic data are available for the endmembers CaNaPO4 and CaKPO4. In this work, the missing data were determined for the low-temperature phase modifications of the endmembers CaNaPO4 and CaKPO4 and three intermediate Ca(Na,K)PO4 compositions. Standard enthalpy of formation ranges from - 2018.3 ± 2.2 kJ mol-1 to - 2030.5 ± 2.1 kJ mol-1 and standard entropy from 137.2 ± 1.0 J mol-1 K-1 to 148.6 ± 1.0 J mol-1 K-1 from sodium endmember b-CaNaPO4 to potassium endmember b0-CaKPO4. Thermodynamic functions are calculated up to 1400 K for endmembers and the sodium-rich intermediate phase b-Ca(Na0.93K0.07)PO4. Functions above 640 K are extrapolated because of the phase transition from low- to high-temperature phase. Impurities in the synthesized intermediate phases c-Ca(Na0.4K0.6)PO4 and c-Ca Na0.35K0.65)PO4 and one additional phase transition around 500 K impeded the determination of high-temperature thermodynamic functions. In general, data for phase transition temperatures agree with the previously reported phase diagrams. KW - Formation enthalpy KW - Heat capacity KW - Phase transformation KW - Bioceramics KW - Phosphorus fertilizer KW - Entropy PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507640 DO - https://doi.org/10.1007/s10853-020-04615-5 VL - 55 SP - 8477 EP - 8490 PB - Springer AN - OPUS4-50764 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schröder, Nina A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Thermodynamic prediction of precipitations behaviour in HAZ of a gas metal arc welded S690QL with varying Ti and Nb content N2 - For a significant increase in the strength of high-strength fine-grained structural steels with a nominal yield strength ≥690 MPa, the addition of microalloying elements such as Nb and Ti is required. The standard specifications for the chemical composition of these steels (e.g., in EN 10025-6) often only give the manufacturer limit contents to achieve the defined properties. The effect of the alloying elements in the heat affected zone (HAZ) is sometimes completely contrary. This makes it difficult to adequately predict the batch dependency regarding weldability and the load-bearing behaviour of the welded joint. Three different micro-alloyed steels of the grade S690QL were produced on a laboratory scale, focusing on different Nb and Ti contents. To investigate the tempering effect, these were gas metal arc welded in three layers. In addition to metallographic investigations of individual HAZ areas, thermodynamic phase calculations were carried out using Thermo-Calc, following variations in the chemical composition. This provides an understanding of phase transformation, precipitation growth, and dissolution during welding as a function of temperature and cooling conditions. The results show a divergent metallurgical behaviour in the HAZ of the three different micro-alloyed steels. Thereby, the Ti micro-alloyed grade showed a strong softening of the HAZ in contrast to the Nb micro-alloyed grade. This can be attributed to a contrary precipitation behaviour during welding. KW - High-strength structural steel KW - Gas metal arc welding KW - HAZ-softening KW - Microalloying influences KW - Thermodynamic simulation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579988 DO - https://doi.org/10.1007/s40194-023-01550-2 SN - 0043-2288 SP - 1 EP - 10 PB - Springer AN - OPUS4-57998 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lozano-Martín, D. A1 - Tuma, Dirk A1 - Kipphardt, Heinrich A1 - Khanipour, Peyman A1 - Chamorro, C. R. T1 - Thermodynamic characterization of the (H2 + C3H8) system significant for the hydrogen economy: Experimental (p, rho, T) determination and equation-of-state modelling N2 - For the gradual introduction of hydrogen in the energy market, the study of the properties of mixtures of hydrogen with typical components of natural gas (NG) and liquefied petroleum gas (LPG) is of great importance. This work aims to provide accurate experimental (p, rho, T) data for three hydrogen-propane mixtures with nominal compositions (amount of substance, mol/mol) of (0.95 H2 + 0.05 C3H8), (0.90 H2 + 0.10 C3H8), and (0.83 H2 + 0.17 C3H8), at temperatures of 250, 275, 300, 325, 350, and 375 K, and pressures up to 20 MPa. A single-sinker densimeter was used to determine the density of the mixtures. Experimental density data were compared to the densities calculated from two reference equations of state: the GERG-2008 and the AGA8-DC92. Relative deviations from the GERG-2008 EoS are systematically larger than those from the AGA8-DC92. They are within the ±0.5% band for the mixture with 5% of propane, but deviations are higher than 0.5% for the mixtures with 10% and 17% of propane, especially at low temperatures and high pressures. Finally, the sets of new experimental data have been processed by the application of two different statistical equations of state: the virial equation of state, through the second and third virial coefficients, B(T, x) and C(T, x), and the PC-SAFT equation of state. KW - Hydrogen-containing gas mixture KW - Density data KW - Equation of state KW - Virial coefficients PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570056 DO - https://doi.org/10.1016/j.ijhydene.2022.11.170 SN - 0360-3199 VL - 48 IS - 23 SP - 8645 EP - 8667 PB - Elsevier B. V. CY - Amsterdam AN - OPUS4-57005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lozano-Martín, D. A1 - Pazoki, F. A1 - Kipphardt, Heinrich A1 - Khanipour, P. A1 - Tuma, Dirk A1 - Horillo, A. A1 - Chamorro, C. R. T1 - Thermodynamic (p, ρ, T) characterization of a reference high-calorific natural gas mixture when hydrogen is added up to 20 % (mol/mol) N2 - The injection of hydrogen into the natural-gas grid is an alternative during the process of a gradual decarbonization of the heat and power supply. When dealing with hydrogen-enriched natural gas mixtures, the performance of the reference equations of state habitually used for natural gas should be validated by using high-precision experimental thermophysical data from multicomponent reference mixtures prepared with the lowest possible uncertainty in composition. In this work, we present experimental density data for an 11-compound high-calorific (hydrogen-free) natural gas mixture and for two derived hydrogen-enriched natural gas mixtures prepared by adding (10 and 20) mol-% of hydrogen to the original standard natural gas mixture. The three mixtures were prepared gravimetrically according to ISO 6142–1 for maximum precision in their composition and thus qualify for reference materials. A single-sinker densimeter was used to determine the density of the mixtures from (250–350) K and up to 20 MPa. The experimental density results of this work have been compared to the densities calculated by three different reference equations of state for natural gas related mixtures: the AGA8-DC92 EoS, the GERG-2008 EoS, and an improved version of the GERG-2008 EoS. While relative deviations of the experimental density data for the hydrogen-free natural gas mixture are always within the claimed uncertainty of the three considered equations of state, larger deviations can be observed for the hydrogen-enriched natural gas mixtures from any of the three equations of state, especially for the lowest temperature and the highest pressures. KW - Hydrogen-enriched natural gas KW - Single-sinker densimeter KW - High-pressure density KW - Equations of state PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604742 DO - https://doi.org/10.1016/j.ijhydene.2024.05.028 SN - 0360-3199 VL - 70 SP - 118 EP - 135 PB - Elsevier BV CY - Amsterdam AN - OPUS4-60474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leers, K. A1 - Arnold, U. A1 - Herzel, Hannes A1 - Adam, Christian A1 - Burkhardt, J. T1 - Thermochemically Treated Sewage Sludge Ash From Pilot-Scale Production as P-Fertilizer for Spring Wheat and Maize in Different Soil Conditions N2 - Background P-fertilizers made from sewage sludge ash (SSA) may be suitable substitutes for rock phosphate (RP)-based fertilizers and contribute to sustainable use of waste. In this context, the thermochemical AshDec treatment of SSA (TC-SSA) has been continuously improved and has emerged as a possible method to produce plant-available and low-pollutant P-fertilizers. Aim Evaluation of the P-fertilizer efficacy of TC-SSA produced in pilot trials in vegetation experiments with different plants, soils, and fertilizer doses. Methods TC-SSA was tested in pot experiments for spring wheat and maize on different soils and at two doses (0.2 and 0.4 g fertilizer P pot−1) and is compared to untreated SSA (USSA), RP, Struvite, triple superphosphate (TSP), and a control without P-fertilization (Zero P). Pot experiments are complemented by an analysis of fertilizer P-solubility. Results P-solubility of SSA with different extraction methods increased due to the thermochemical treatment, whereas the water-insoluble property remained. In contrast to RP or USSA, TC-SSA enriched calcium–acetate–lactate extractable soil P to the same extent as TSP. Plant biomass and P-uptake increased with TC-SSA compared to Zero P, RP, and USSA and were in most cases equal to TSP fertilization under different soil conditions. In contrast, the effects of RP and USSA varied among soils but, mostly, did not exceed plant biomass and P-uptake of the unfertilized control. Conclusion TC-SSA has an increased fertilizer efficacy compared to USSA and is an effective P-fertilizer for spring wheat and maize in different soil conditions. KW - Phosphorus KW - Fertilizer KW - Thermochemical KW - Maize PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648251 DO - https://doi.org/10.1002/jpln.70035 SN - 1522-2624 VL - 189 IS - 1 SP - 81 EP - 93 PB - Wiley-VCH AN - OPUS4-64825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Smol, M. A1 - Adam, Christian A1 - Kugler, Stefan T1 - Thermochemical Treatment of Sewage Sludge Ash (SSA)—Potential and Perspective in Poland N2 - Phosphorus (P) recovery from sewage sludge ash (SSA) is one of the most promising approaches of phosphate rock substitution in mineral fertilizers and might be a sustainable way to secure supply of this raw material in the future. In the current investigation, the process of thermochemical treatment of SSA was applied to SSA coming from selected mono-incineration plants of municipal sewage sludge in Poland (Cracow, Gdansk, Gdynia, Lodz, Kielce and Szczecin). The Polish SSA was thermochemically converted in the presence of sodium (Na) additives and a reducing agent (dried sewage sludge) to obtain secondary raw materials for the production of marketable P fertilizers. The process had a positive impact on the bioavailability of phosphorus and reduced the content of heavy metals in the obtained products. The P solubility in neutral Ammonium citrate, an indicator of its bioavailability, was significantly raised from 19.7–45.7% in the raw ashes and 76.5–100% in the thermochemically treated SSA. The content of nutrients in the recyclates was in the range of 15.7–19.2% P2O5, 10.8–14.2% CaO, 3.5–5.4% Na2O, 2.6–3.6% MgO and 0.9–1.3% K2O. The produced fertilizer raw materials meet the Polish norms for trace elements covered by the legislation: the content of lead was in the range 10.2–73.1 mg/kg, arsenic 4.8–22.7 mg/kg, Cadmium 0.9–2.8 mg/kg and mercury <0.05 mg/kg. Thus, these products could be potentially directly used for fertilizer production. This work also includes an analysis of the possibilities of using ashes for fertilizer purposes in Poland, based on the assumptions indicated in the adopted strategic and planning documents regarding waste management and fertilizer production. KW - Sewage Sludge Ashes KW - Critical raw materials KW - Phosphorus KW - Fertilizer KW - Sewage Sludge PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514468 DO - https://doi.org/10.3390/en13205461 VL - 13 IS - 20 SP - 5461 AN - OPUS4-51446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmalz, Alina A1 - Eby, Charles Gaston A1 - Moss, Caitlin A1 - Bhattacharya, Biswajit A1 - Emmerling, Franziska T1 - Thermally Robust 1D Cu(I) Phosphonate Coordination Polymer Exhibiting Enhanced Proton Conductivity via Humidity‐Driven Pathways N2 - The development of thermally stable solid-state proton conductors (SSPCs) is crucial for advancing energy-conversion devices such as proton-exchange membrane fuel cells (PEMFCs). In this work, we report the solvothermal synthesis and characterization of a novel, 1D Cu(I) coordination polymer, {Cu(ADP)0.5(BPY)}n (BAM-5), based on anthracenediylphosphonate (H2ADP) and 4,40 -bipyridine (BPY). Single-crystal X-ray diffraction revealed that BAM-5 crystallizes in the triclinic space group P1 and shows a 1D ladder structure connected by the H2ADP and organic BPY linkers, which is assembled into a 2D layer via O−H···O hydrogen bonding interactions between uncoordinated oxygen and the O−H of the phosphonate group. Thermogravimetric and dynamic water sorption analysis demonstrated exceptional thermal robustness of BAM-5 until 230°C and notable water affinity. Proton conductivity measurements found increasing proton conductive properties with increasing temperature and relative humidity.The latter is correlated with the material’s water uptake since the structure itself does not contain any permanent lattice water molecules. A maximum proton conductivity of 6.6 × 10−6 S cm−1 was found at 80°C and 98% RH. To the best of our knowledge, no dense, nonporous 1D coordination polymer without lattice or coordinated solvent molecules has shown comparable proton con� ductivity. The high activation energy suggests a combination of both, a Grotthuss-type proton hopping through the hydrogen� bonded framework, and a vehicular process, in which protons are carried along with absorbed water molecules. KW - Coordination polymers KW - Phosphonate ligand KW - Proton conduction KW - X-ray diffraction PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651382 DO - https://doi.org/10.1002/zaac.202500187 SN - 0044-2313 SP - 1 EP - 8 PB - Wiley VHC-Verlag AN - OPUS4-65138 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szczerba, Wojciech A1 - Schott, M. A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas A1 - Kurth, D.G. T1 - Thermally induced structural rearrangement of the Fe(II) coordination geometry in metallo-supramolecular polyelectrolytes N2 - Rigid rod-type metallo-supramolecular coordination polyelectrolytes with Fe(II) centres (Fe-MEPEs) are produced via the self-assembly of the ditopic ligand 1,4-bis(2,2':6',2''-terpyridine-4'-yl)benzene (tpy-ph-tpy) and Fe(II) acetate. Fe-MEPEs exhibit remarkable electrochromic properties; they change colour from blue to transparent when an electric potential is applied. This electrochemical process is generally reversible. The blue colour in the ground state is a result of a metal-to-ligand charge transfer at the Fe(II) centre ion in a quasi-octahedral geometry. When annealed at temperatures above 100 °C, the blue colour turns into green and the formerly reversible electrochromic properties are lost, even after cooling down to room temperature. The thermally induced changes in the Fe(II) coordination sphere are investigated in situ during annealing of a solid Fe-MEPE using X-ray absorption fine structure (XAFS) spectroscopy. The study reveals that the thermally induced transition is not accompanied by a redox process at the Fe(II) centre. From the detailed analysis of the XAFS spectra, the changes are attributed to structural changes in the coordination sphere of the Fe(II) site. In the low temperature state, the Fe(II) ion rests in a quasi-octahedral coordination environment surrounded by six nitrogen atoms of the pyridine rings. The axial Fe–N bond length is 1.94 Å, while the equatorial bond length amounts to 1.98 Å. In the high temperature state, the FeN6-site exhibits a distortion with the axial Fe–N bonds being shortened to 1.88 Å and the equatorial Fe–N bonds being elongated to 2.01 Å. KW - Metallo-supramolecular polyelectrolytes KW - Electrochromism KW - XANES KW - EXAFS KW - Local structure KW - Thermal stability PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317331 DO - https://doi.org/10.1039/c4cp01187b SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 36 SP - 19694 EP - 19701 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-31733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kovacevic, E. A1 - Strunskus, T. A1 - Santhosh, N. M. A1 - Zavasnik, Z. A1 - Unger, Wolfgang A1 - Sauvage, T. A1 - Ammar, M.-R. A1 - Cvelbar, U. A1 - Berndt, J. T1 - Thermal stability studies of plasma deposited hydrogenated carbon nitride nanostructures N2 - Thermally stable carbon nitride nanostructures have potential applications in surface coatings and automotive fields. In this work, hydrogenated nitrogen-rich carbon nitride nanoparticles have been synthesised via low-pressure low-power plasma vapour deposition technique from methane/Nitrogen gas mixture in a dry process. Thermal stability of the initially prepared hydrogenated carbon Nitride structures has been analysed by near-edge X-ray absorption fine-structure spectroscopy (NEXAFS, insitu), Raman spectroscopy, scanning and transmission electron microscopy and nuclear reaction Analysis (NRA). Thermal studies reveal the excellent stability of the material and nitrogen-rich characteristics (N/C ratio 0.5e0.2 ± 0.01). The obtained results suggest transformation of sp3-rich as-deposited carbon Nitride into sp2-carbon phase with more graphitic features upon thermal annealing. Such in-situ thermal studies of plasma deposited carbon nitrides confirm the conversion of sp3-rich phase to sp2-rich carbon phase at the critical temperature (about 450 K), without a huge loss in nitrogen content. The analysis revealed that the material is a stable plasma deposit after this critical temperature up to >1100 K. Additionally, super hydrophilic carbon nitride nanostructure transforms into a hydrophobic surface after thermal annealing. These thermally stable hydrophobic carbon nitride nanoparticles could be used as a promising material for the hydrophobic coatings for various applications, especially for harsh conditions. KW - Carbon nanoparticles KW - Hydrogenated nanostructures KW - Plasma deposition KW - NEXAFS KW - Thermal annealing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536163 DO - https://doi.org/10.1016/j.carbon.2021.08.008 SN - 0008-6223 VL - 184 SP - 82 EP - 90 PB - Elsevier Ltd. AN - OPUS4-53616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Amano, Kofi Owusu Ansah A1 - Tschirschwitz, Rico A1 - Gimadieva, Elena A1 - Köhler, Florian A1 - Krause, Ulrich T1 - Thermal runaway and explosibility of the gas release from 18650 sodium-ion cells of NFM chemistry N2 - The present study investigates the thermal runaway behaviour and explosibility of the gas mixture released from sodium-ion batteries (SIBs). A total of 30 tests comprising two test series were performed using 18650 SIBs with a NaNi1/3Fe1/3Mn1/3O2 (NFM) chemistry. The cells of SOC level = 0 %, 25 %, 50 %, 75 % and 100 % were subjected to thermal abuse inside a 10 L pressurized reaction vessel. In test series 1, the tests were performed in an air atmosphere. In test series 2, an inert atmosphere was used. First, the total amount of gas released from the SIBs was calculated based on the temperature and pressure measured in the reaction vessel. Subsequently, a gas composition analysis was performed using a Fourier-transformed infrared (FTIR) spectrometer. This study revealed that the thermal runaway in SIBs could be categorized into four phases. At the onset of thermal runaway, the thermal runaway-induced explosion of the cells resulted in a rate of temperature rise ranging from 2 K/s to 70 K/s. The investigation further revealed a peak reaction temperature of 415 ◦C and a maximum pressure of 4 bar could be reached at thermal runaway in the 10 L vessel. The gas release of up to 5 ± 0.3 L (4 ± 0.2 L/Ah, 1.3 ± 0.1 L/Wh) from test series 1 and 2.4 ± 0.2 L (2 ± 0.1 L/Ah, 0.53 ± 0.04 L/Wh) from test series 2 showed a dependence on SOC and failure environment used. By applying Le Chatelier's mixing rule, the measured gas release from the air atmosphere showed a calculated lower explosion limit and upper explosion limit values of 4.8 % and 24 % in volume fraction, respectively. KW - Sodium-ion battery KW - Thermal runaway KW - Gas release KW - Gas explosion KW - Explosion limit PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631782 DO - https://doi.org/10.1016/j.est.2025.116614 SN - 2352-152X VL - 122 SP - 1 EP - 16 PB - Elsevier Ltd. AN - OPUS4-63178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - zur Nedden, Philipp Maximilian A1 - von Saldern, Jakob Georg Raimund A1 - Beuth, Jan Paul A1 - Orchini, Alessandro T1 - Thermal Radiation Of Inclined Large Scale Hydrogen Jet Flames N2 - In order to assess the thermal radiation emanating from hydrogen jet flames, experiments under real scale conditions were carried out at the Test Site Technical Safety of BAM. Herein, the behavior of inclined hydrogen jet flames was investigated. The aim of the work is to determine the Surface Emissive Power (SEP) and radiant heat fraction of these flames and to provide a reliable dataset for model evaluation purposes. Since the aforementioned values are not directly measurable, the incident heat radiation was measured at defined distances from the flame, as well as the flame’s shape and size. The required values were then derived from these measurements. The hydrogen releases ranged from 0.0125 kg/s to 0.175 kg/s with a 30 mm orifice. The mass flows were held constant during the releases, nevertheless a transient behavior of the flame could be observed since the experiments were carried out under open field conditions, with unsteady wind fields. In the literature, the flame lengths are often determined using visible light imaging, either by injecting coloring substances in the low light emitting hydrogen jet flame or by carrying out the measurements in darkness. In this work the jet flames were visualized using infrared (IR) and OH* imaging. The recorded flame shapes and resulting flame lengths are compared. Results from this showed that the flame lengths determined with OH* and IR recordings differ greatly. A flame length ratio lf OH*/lf IR in the range of 0.47–0.62 can be found. In addition, the SEP differ also in the range of 10 kW/m2–16 kW/m2 (IR) and 40 kW/m2–80 kW/m2 (OH*) for hydrogen jet flames due to differences in the determined flame surface. Conclusions regarding the determined xRAD values for IR and OH* result in approximately the same range of 0.031–0.043. T2 - 11th Iinternational conference on hydrogen safety 2025 CY - Seoul, Republic of Korea DA - 22.09.2025 KW - Hydrogen safety KW - Jet flames KW - Thermal radiation KW - Large scale experiment PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655181 DO - https://doi.org/10.58895/hysafe.27 SN - 2943-5935 VL - 3 IS - 1 SP - 39 EP - 50 PB - Karlsruhe Institute of Technology Library AN - OPUS4-65518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohr, Gunther A1 - Chaudry, Mohsin Ali A1 - Scheuschner, Nils A1 - Blasón Gonzalez, Sergio A1 - Madia, Mauro A1 - Hilgenberg, Kai T1 - Thermal history transfer from complex components to representative test specimens in laser powder bed fusion N2 - Additively manufactured components are characterized by heterogeneous mechanical properties due to variations of the microstructure, flaws and residual stresses resulting from the inhomogeneous fabrication process. The large number of influencing factors poses a further challenge in understanding the correlation between material properties, process parameters and component geometry. Therefore, the qualification of components based on witness specimens produced within the same job is questionable. This work aims to present a new strategy for the characterization of PBF-LB/M components based on representative specimens. The key assumption is the feasibility of a transfer of the thermal history from a component to a specimen. It is assumed that similar material properties are determined for components and specimens produced adopting a similar thermal history. After the definition of a region of interest in the component, a combination of thermal analyses by means of finite elements and in-situ experimental determination of the thermal history through infrared thermography is used to produce test coupons with a similar thermal history. The effectiveness of the procedure is demonstrated on a pressure vessel for applications in the chemical industry. KW - Additive manufacturing KW - Heat accumulation KW - Thermal history KW - In situ monitoring KW - Process simulation KW - Representative specimens PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602651 DO - https://doi.org/10.1007/s40964-024-00689-8 SN - 2363-9512 SN - 2363-9520 SP - 1 EP - 16 PB - Springer CY - Cham, Switzerland AN - OPUS4-60265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lunkenheimer, P. A1 - Loidl, A. A1 - Riechers, Birte A1 - Zaccone, A. A1 - Samwer, K. T1 - Thermal expansion and the glass transition N2 - Melting is well understood in terms of the Lindemann criterion, which essentially states that crystalline materials melt when the thermal vibrationsof their atoms become so vigorous that they shake themselves free of the binding forces. This picture does not necessarily have to hold for glasses, where the nature of the solid–liquid cross-over is highly debated. The Lindemann criterion implies that the thermal expansion coefficients of crystals are inversely proportional to their melting temperatures. Here we find that, in contrast, the thermal expansion coefficient of glasses decreases more strongly with increasing glass temperature, which marks the liquid–solid cross-over in this material class. However, this proportionality returns when the thermal expansion coefficient is scaled by the fragility, a measure of particle cooperativity. Therefore, for a glass to become liquid, it is not sufficient to simply overcome the interparticle binding energies. Instead, more energy must be invested to break up the typical cooperative particle network that is common to glassy materials. The thermal expansion coefficient of the liquid phase reveals similar anomalous behaviour and is universally enhanced by a constant factor of approximately 3. These universalities allow the estimation of glass temperatures from thermal expansion and vice versa. KW - Glass transition KW - Lindemann criterion KW - Thermal expansion KW - Glass PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570267 DO - https://doi.org/10.1038/s41567-022-01920-5 SN - 1745-2473 SP - 1 EP - 7 PB - Nature Publishing Group CY - London AN - OPUS4-57026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pittrich, Tim A1 - Jansen, Daniel A1 - Weise, Frank A1 - Stelzner, Ludwig A1 - Dehn, Frank T1 - Thermal decomposition in blended cement systems and its effect on fire-induced concrete spalling: Insights from XRD and TGA N2 - Blended cements are gaining increasing popularity due to their lower CO2-footprint in comparison to ordinary Portland cement (OPC). However, this growing use raises the potential risk of buildings made with blended cement concrete being exposed to fire, which can lead to heavy damages caused by explosive concrete spalling. It has already been shown that the cement type strongly influences the fire-induced concrete spalling and the thermally induced moisture transport, however, to understand the mechanisms behind these findings the thermal decomposition behavior of the cementitious matrix must be investigated more systematically. Therefore, the phase content of three blended cement pastes (CEM II/A-LL, CEM III/A and CEM II/B-Q) was studied in comparison with a Portland cement paste (CEM I) after temperature exposure to 20 ◦C, 105 ◦C, 300 ◦C and 500 ◦C. Clear differences in the initial phase composition and their dehydration behavior between the individual cement types were recognized. In conclusion, blended cements showed lower amounts of AFt and AFm phases and additionally lower amounts of portlandite and C-(A)-S-H were found in CEM III/A and CEM II/B-Q pastes. The results suggest that higher AFt and AFm contents in CEM I, which are associated with greater water release at relatively low temperatures may ultimately reduce the spalling risk. Furthermore, C-(A)-S-H in CEM III/A and CEM II/B-Q showed increased thermal stability and large amounts of non-hydrated phases were found in every blended cement paste. Both of those aspects might contribute to thermomechanical spalling and the overall increased spalling susceptibility observed in blended cement concrete. KW - Fire concrete spalling KW - High temperatures KW - Blended cements KW - Dehydration KW - XRD KW - TGA PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653698 DO - https://doi.org/10.1016/j.cscm.2026.e05784 SN - 2214-5095 VL - 24 SP - 1 EP - 14 PB - Elsevier Ltd. AN - OPUS4-65369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -