TY - JOUR A1 - Arlt, Tobias A1 - Manke, I. A1 - Wippermann, K. A1 - Schröder, A. A1 - Mergel, J. A1 - Riesemeier, Heinrich A1 - Banhart, J. T1 - Röntgen-Kanten-Tomografie und -Radiografie zur Untersuchung von Alterungseffekten in Brennstoffzellenmaterialien KW - Resolution neutron-radiography KW - Local current distribution KW - Water transport KW - Carbon-dioxide KW - Methanol KW - Platinum KW - Oxidation PY - 2010 SN - 0025-5300 VL - 52 IS - 10 SP - 692 EP - 697 PB - Hanser CY - München AN - OPUS4-23045 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Manke, I. A1 - Hartnig, C. A1 - Kardjilov, N. A1 - Riesemeier, Heinrich A1 - Goebbels, Jürgen A1 - Kuhn, R. A1 - Krüger, P. A1 - Banhart, J. T1 - In situ synchrotron X-ray radiography investigations of water transport in PEM fuel cells N2 - Water transport in an operating PEM fuel cell was investigated with synchrotron X-ray radiography with a spatial resolution of 3 µm and a temporal resolution of 5 s. This method allows for the detection of water accumulations with less than 10 µm diameter. We demonstrate that synchrotron X-ray imaging can dramatically expand the possibilities of imaging with high spatial and time resolution, especially as a complement to neutron radiography. Water transport processes from the first appearance of small water accumulations in the gas diffusion layer to their transport into the channel system were analysed in situ. Correlations between local effects such as water formation and operating conditions of the whole system, e.g. power variations, were found. A recently described eruptive water transport mechanism is analysed in detail. KW - Fuel cell KW - Gas diffusion layer KW - Imaging KW - Synchrotron KW - X-ray radiography KW - Two-phase flow KW - Water transport PY - 2010 DO - https://doi.org/10.1002/fuce.200800123 SN - 1615-6846 SN - 1615-6854 VL - 10 IS - 1 SP - 26 EP - 34 PB - Wiley-VCH CY - Weinheim AN - OPUS4-22730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zabler, S. A1 - Rueda, A. A1 - Rack, A. A1 - Riesemeier, Heinrich A1 - Zaslansky, P. A1 - Manke, I. A1 - Garcia-Moreno, F. A1 - Banhart, J. T1 - Coarsening of grain-refined semi-solid Al-Ge32 alloy: X-ray microtomography and in situ radiography KW - Microtomography KW - Radiography KW - 2D/3D imageanalysis KW - Technical binary alloys KW - LSW PY - 2007 DO - https://doi.org/10.1016/j.actamat.2007.05.028 SN - 1359-6454 SN - 1873-2453 VL - 55 IS - 15 SP - 5045 EP - 5055 PB - Elsevier Science CY - Kidlington AN - OPUS4-20583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hartnig, C. A1 - Manke, I. A1 - Schloesser, J. A1 - Krüger, P. A1 - Kuhn, R. A1 - Riesemeier, Heinrich A1 - Wippermann, K. A1 - Banhart, J. T1 - High resolution synchrotron X-ray investigation of carbon dioxide evolution in operating direct methanol fuel cells N2 - The carbon dioxide evolution and bubble formation in an operating fuel has been studied by means of synchrotron X-ray radiography. Two different observation directions have been chosen: a through-plane insight has been employed to track the formation of bubbles starting at the corner of the lands of the flow field; a depth profile of the carbon dioxide evolution has been derived from cross sectional studies describing an affected area of up to 100 µm. The dynamics of the bubble formation and detachment of the bubbles from the position of formation is strongly correlated with the current density. Cracks and breaks in the catalyst layer which result from the preparation process are visible under operating conditions and a possible swelling of the catalyst layer does not reach a complete vanishing of the cracks. KW - DMFC KW - Carbon dioxide evolution KW - Synchrotron radiography KW - In situ study KW - Cross section KW - Through-plane PY - 2009 DO - https://doi.org/10.1016/j.elecom.2009.05.047 SN - 1388-2481 VL - 11 IS - 8 SP - 1559 EP - 1562 PB - Elsevier CY - Amsterdam AN - OPUS4-20577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Treimer, W. A1 - Feye–Treimer, U. A1 - Radke, C. A1 - Hilger, A. A1 - Neumann, O. A1 - Manke, I. A1 - Haibel, A. A1 - Rack, A. A1 - Riesemeier, Heinrich T1 - Investigations of mamma biopsies by means of µ-tomography PY - 2005 UR - http://www.helmholtz-berlin.de/media/media/oea/web/pr_webseite/druckschriften/berichte/bessy/annualreport2004.pdf#page=452 SN - 0179-4159 SP - 452 EP - 453 PB - Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung CY - Berlin AN - OPUS4-7383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maier, W. A1 - Arlt, Tobias A1 - Wannek, C. A1 - Manke, I. A1 - Riesemeier, Heinrich A1 - Krüger, P. A1 - Scholta, J. A1 - Lehnert, W. A1 - Banhart, J. A1 - Stolten, D. T1 - In-situ synchrotron X-ray radiography on high temperature polymer electrolyte fuel cells N2 - In contrast to classical low temperature polymer electrolyte fuel cells (LT-PEFCs), the membrane conductivity in high temperature polymer electrolyte fuel cells (HT-PEFCs) (operating temperature ~ 160 °C) is based on proton transport within phosphorus-oxygen acids at different levels of hydration, orthophosphoric acid (H3PO4) being the simplest example. We present for the first time in-situ synchrotron X-ray radiography measurements applied to a HT-PEFC to gain insight into the local composition of the membrane electrode assembly (MEA) under dynamic operating conditions. Transmission changes during the radiographic measurements exhibit a clear influence of the formation of product water on the membrane composition. KW - HT-PEFC KW - Synchrotron x-ray radiography KW - Membrane electrode assembly (MEA) KW - Phosphoric acid PY - 2010 DO - https://doi.org/10.1016/j.elecom.2010.08.002 SN - 1388-2481 VL - 12 IS - 10 SP - 1436 EP - 1438 PB - Elsevier CY - Amsterdam AN - OPUS4-23962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tötzke, C. A1 - Manke, I. A1 - Hartnig, C. A1 - Kuhn, R. A1 - Riesemeier, Heinrich A1 - Banhart, J. T1 - Investigation of carbon fiber gas diffusion layers by means of synchrotron X-ray tomography N2 - The 3-dimensional spatial distribution of liquid water in different gas diffusion layer (GDL) materials was analyzed using synchrotron X-ray tomography. The capability of the method was demonstrated by virtually separating the GDL components in order to facilitate individual analysis of fiber material, liquid water and gas filled pore spaces. The influence of hydrophobic surface treatment on the water distribution in the GDL was illustrated by analyzing three GDL materials with different degrees of hydrophobicity. In the least hydrophobic sample, liquid water tends to form larger clusters which stretch out about several hundred µm inside the porous GDL. In contrast, only small water clusters were found in the strongly hydrophobic material with high Polytetrafluoroethylene (PTFE)-content as the liquid is partially pressed out of the GDL. Additionally, the influence of fiber orientation on the water distribution in the felt material was demonstrated. KW - Synchrotron X-ray tomography KW - Fuel cell KW - Gas diffusion layer (GDL) materials KW - Analysis of fiber material PY - 2011 DO - https://doi.org/10.1149/1.3635571 SN - 1938-6737 SN - 1938-5862 VL - 41 IS - 1 SP - 379 EP - 386 CY - Pennington, NJ, USA AN - OPUS4-25348 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Arlt, Tobias A1 - Manke, I. A1 - Wippermann, K. A1 - Riesemeier, Heinrich A1 - Mergel, J. A1 - Banhart, J. T1 - Investigation of the local catalyst distribution in an aged direct methanol fuel cell MEA by means of differential synchrotron X-ray absorption edge imaging with high energy resolution N2 - Synchrotron X-ray absorption edge imaging with high energy resolution was applied to study aging of fuel cell catalyst materials. The combination of an imaging and a high X-ray energy resolution set-up allows acquiring spatially resolved XAS (XANES and EXAFS) spectra. We analyzed the two-dimensional distribution of Pt and Ru in fresh and aged fuel cell catalysts. Spatially resolved XAS images were taken at the RuK edge and at the PtL3 edge. Taking radiographs above and below the absorption edges provides quantitative information about the thickness of the catalytic materials and additional chemical information. A strong influence of the flow field channels and the structure of the gas diffusion layers on the thicknesses of the catalytic elements were found: a thinner catalyst layer was found below the ribs of the flow field geometries as well as under crossing points of fiber bundles of the woven gas diffusion layers. KW - XAS KW - X-ray energy edge KW - Membrane electrode assembly KW - Direct methanol fuel cell KW - Aging mechanism KW - X-ray synchrotron radiography PY - 2013 DO - https://doi.org/10.1016/j.jpowsour.2012.08.038 SN - 0378-7753 VL - 221 SP - 210 EP - 216 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-27372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Dabah, Eitan A1 - Hilger, A. A1 - Kardjilov, N. A1 - Manke, I. A1 - Kannengießer, Thomas T1 - Neutron imaging of hydrogen in steels N2 - Transmission images with neutrons show a high contrast between hydrogen and iron when using state-of-the-art scintillator materials and digital Cameras. Monitoring the 2D hydrogen distribution evolution with good temporal resolution is possible if a high flux of neutrons is provided. The mass transport of hydrogen can be quantified by Converting the intensity distribution of the images in a hydrogen concentration distribution by using Standards with known composition and similar thickness. Then neutron radiography can be used quantitatively as a non-destructive measurement technique to determine diffusion coefficients e.g. for hydrogen in Steel. We report about measurements at Research Reactors in Germany. The capabilities and limitations, s well as perspectives of this method will be discussed and illustrated with selected examples. T2 - Materials Science & Technology (MS&T) 2013 CY - Montreal, Quebec, Canada DA - 27.10.2013 KW - Neutron radiography KW - Hydrogen KW - Diffusion KW - Steel PY - 2013 SP - 945 EP - 950 PB - Curran CY - Red Hook, NY AN - OPUS4-29506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Griesche, Axel A1 - Dabah, Eitan A1 - Kannengießer, Thomas A1 - Kardjilov, N. A1 - Hilger, A. A1 - Manke, I. T1 - Three-dimensional imaging of hydrogen blister in iron with neutron tomography N2 - We investigated hydrogen embrittlement and blistering in electrochemically hydrogen-charged technical iron samples at room temperature. Hydrogen-stimulated cracks and blisters and the corresponding hydrogen distributions were observed by neutron tomography. Cold neutrons were provided by the research reactor BER II to picture the sample with a spatial resolution in the reconstructed three-dimensional model of ~25 µm. We made the unique observation that cracks were filled with molecular hydrogen and that cracks were surrounded by a 50 µm wide zone with a high hydrogen concentration. The zone contains up to ten times more hydrogen than the bulk material. The hydrogen enriched zone can be ascribed to a region of increased local defect density. Hydrogen also accumulated at the sample surface having the highest concentration at blistered areas. The surfaces of the brittle fractured cracks showed micropores visualized by scanning electron microscopy. The micropores were located at grain boundaries and were surrounded by stress fields detected by electron backscattered diffraction. The cracks clearly originated from the micropores. KW - Hydrogen embrittlement KW - Hydrogen diffusion KW - In situ KW - Neutron tomography KW - Iron PY - 2014 DO - https://doi.org/10.1016/j.actamat.2014.06.034 SN - 1359-6454 SN - 1873-2453 VL - 78 SP - 14 EP - 22 PB - Elsevier Science CY - Kidlington AN - OPUS4-31068 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Arlt, T. A1 - Kardjilov, N. A1 - Kupsch, Andreas A1 - Manke, I. A1 - Salvemini, F. A1 - Grazzi, F. T1 - Neutronen-Laminografie am Beispiel eines historischen Artefakts T1 - Neutron computed laminography on an ancient metal artifact N2 - Die Computer-gestützte Laminografie (CL) wurde als komplementäre Methode zur Computertomografie für die dreidimensionale Bildgebung von lateral ausgedehnten Objekten entwickelt. Ursprünglich für medizinische Zwecke verwendet, wurde diese Methode kürzlich als zerstörungsfreie nicht-invasive Methode nicht nur in der Materialforschung, sondern auch mit steigendem Interesse für kunsthandwerkliche und historische Objekte eingesetzt. Hier wird die Computer-gestützten Laminografie mit polychromatischer Neutronenstrahlung an einer historischen Tsuba eingesetzt, einem Stichblatt eines japanischen Schwerts. Eine Analyse der Lötstellen gibt Rückschlüsse auf das Herstellungsverfahren. Zudem wurden unterschiedliche Materialsysteme gefunden, vermutlich um dem Tsuba lokal eine höhere Stabilität zu verleihen. Die Messungen wurden an der Imaging-Beamline CONRAD-2 an der Neutronenquelle BER 2 des Helmholtz-Zentrums Berlins (HZB) durchgeführt. KW - Neutronenlaminographie KW - Computertomographie PY - 2018 DO - https://doi.org/10.3139/120.111261 SN - 0025-5300 VL - 60 IS - 12 SP - 1209 EP - 1214 PB - Carl Hanser Verlag CY - München AN - OPUS4-46936 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Lück, S. A1 - Schmidt, V. A1 - Grothausmann, R. A1 - Hilger, A. A1 - Manke, I. T1 - Missing wedge computed tomography by iterative algorithm DIRECTT N2 - A strategy to mitigate typical reconstruction artefacts in missing wedge computed tomography is presented. These artefacts appear as elongations of reconstructed details along the mean direction (i.e. the symmetry centre of the projections). Although absent in standard computed tomography applications, they are most prominent in advanced electron tomography and also in special topics of X-ray and Neutron tomography under restricted geometric boundary conditions. We investigate the Performance of the DIRECTT (Direct Iterative Reconstruction of Computed Tomography Trajectories) algorithm to reduce the directional artefacts in standard procedures. In order to be sensitive to the anisotropic nature of missing wedge artefacts, we investigate isotropic substructures of metal foam as well as circular disc models. Comparison is drawn to filtered backprojection and algebraic techniques. Reference is made to reconstructions of complete data sets. For the purpose of assessing the reconstruction Quality, Fourier transforms are employed to visualize the missing wedge directly. Deficient reconstructions of disc models are evaluated by a length-weighted boundary orientations. The DIRECTT results are assessd at different signal-to-noise ratios by means of local and integral evaluation Parameters. KW - Tomography KW - Algorithm KW - Reconstruction KW - Computed tomography KW - Electron tomography KW - Image morphology KW - Iterative reconstruction KW - Missing wedge PY - 2016 DO - https://doi.org/10.1111/jmi.12313 SN - 1365-2818 VL - 261 IS - 1 SP - 36 EP - 45 PB - Wiley CY - Hoboken, New Jersey, USA AN - OPUS4-35801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -