TY - JOUR A1 - Griesche, Axel A1 - Dabah, Eitan A1 - Kardjilov, N. A1 - Hilger, A. A1 - Manke, I. A1 - Kannengießer, Thomas T1 - Imaging of hydrogen in steels using neutrons N2 - We investigated the hydrogen distribution spatially and temporally in technical iron at room temperature. Samples were charged electrochemically and subsequently analysed by means of neutron radiography and tomography. The radiographic images allowed for a time-resolved analysis of hydrogen fluxes. The three-dimensional distribution of hydrogen measured by neutron tomography delivered valuable information for the damage analysis of hydrogen-induced cracks. For the first time hydrogen concentration gradients inside the material could be detect directly together with the cracks. The neutron radiography and tomography results were gained at the Research Reactor BER II of the HZB in Berlin. KW - Hydrogen embrittlement KW - Hydrogen diffusion KW - Neutron tomography KW - Blister PY - 2014 DO - https://doi.org/10.3139/146.111043 SN - 1862-5282 VL - 105 IS - 7 SP - 640 EP - 644 PB - Carl Hanser CY - München AN - OPUS4-31084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dabah, Eitan A1 - Pfretzschner, Beate A1 - Schaupp, Thomas A1 - Kardjilov, N. A1 - Manke, I. A1 - Boin, M. A1 - Woracek, R. A1 - Griesche, Axel T1 - Time-resolved Bragg-edge neutron radiography for observing martensitic phase transformation from austenitized super martensitic steel N2 - Neutron Bragg-edge imaging was applied for the visualization of a γ-Austenite to α'-martensite phase transformation. In the present study, a super martensitic stainless steel sample was heated until complete austenitization and was subsequently cooled down to room temperature. The martensitic phase Transformation started at Ms = 190 °C. Using a monochromatic neutron beam with λ = 0.390 nm, the transmitted intensity was significantly reduced during cooling below Ms, since the emerging martensitic phase has a higher attenuation coefficient than the austenitic phase at this wavelength. The phase Transformation process was visualized by filming the transmission images from a scintillator screen with a CCD camera with a temporal resolution of 30 s and a spatial resolution of 100 µm. KW - Neutron imaging KW - Bragg-edge imaging KW - Phase transformation PY - 2017 DO - https://doi.org/10.1007/s10853-016-0642-9 SN - 0022-2461 SN - 1573-4803 VL - 52 IS - 6 SP - 3490 EP - 3496 AN - OPUS4-38574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kardjilov, N. A1 - Hilger, A. A1 - Manke, I. A1 - Banhart, J. A1 - Griesche, Axel T1 - Imaging with Cold Neutrons at the CONRAD-2 Facility N2 - CONRAD-2 is an imaging instrument using low-energy (cold) neutrons. The instrument is installed at the end of a curved neutron guide which avoids the direct line of sight towards the reactor core. This ensures a very low background of high-energy neutrons and. photons at the sample position. The cold neutron beam provides a wavelength range which is suitable for phase-and diffraction-contrast imaging such as grating interferometry and Bragg edge mapping. The instrument is well suited for high resolution imaging due to the high efficiency of the very thin scintillators that can be used for the detection of cold neutrons. An instrument upgrade was performed recently as a part of an upgrade program for the cold neutron instrumentation at HZB. The parameters of the instrument as well as some research highlights will be presented. T2 - 10th World Conference on Neutron Radiography (WCNR) CY - Grindelwald, SWITZERLAND DA - 05.10.2014 KW - iron embrittlement KW - neutron imaging KW - neutron instrumentation KW - cold neutrons PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-373239 DO - https://doi.org/10.1016/j.phpro.2015.07.008 SN - 1875-3892 VL - 69 SP - 60 EP - 66 PB - Elsevier B.V. CY - Amsterdam, NL AN - OPUS4-37323 LA - eng 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 - 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 - Lange, Axel A1 - Kupsch, Andreas A1 - Hentschel, Manfred P. A1 - Manke, I. A1 - Kardjilov, N. A1 - Arlt, Tobias A1 - Grothausmann, R. T1 - Reconstruction of limited computed tomography data of fuel cell components using direct iterative reconstruction of computed tomography trajectories N2 - CT (computed tomography) reconstructions of fuel cell components of a yet unrivaled spatial resolution and quality are presented. This is achieved by application of the novel DIRECTT (Direct Iterative Reconstruction of Computed Tomography Trajectories) algorithm. We focus on two different key issues which essentially rule the fuel cell's durability on different length scales and physical interactions. On the resolution scale of some 100 µm agglomerations of condensed water in flow-field channels are detected by means of quasi-in situ neutron CT (after operation). Five orders of magnitude below nanometer sized Ru catalyst particles on carbon black support are visualized by electron tomography. Both types of experiments are especially adapted to the type of material involved but they are accompanied by severe deviations from ideal CT measuring conditions, as well. In order to overcome the tremendous reconstruction artifacts of standard algorithms, we employ DIRECTT which is described in detail. Comparisons of DIRECTT reconstructions to the conventional filtered back projection, prove the significant improvements in both experimental methods. KW - PEM fuel cell KW - Neutron computed tomography KW - Electron tomography KW - Reconstruction algrorithm KW - Water management KW - Catalyst PY - 2011 DO - https://doi.org/10.1016/j.jpowsour.2010.10.106 SN - 0378-7753 VL - 196 IS - 12 SP - 5293 EP - 5298 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-23589 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 - Strobl, M. A1 - Dawson, M. A1 - Grünzweig, C. A1 - Behr, G. A1 - Hentschel, Manfred P. A1 - David, C. A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Banhart, J. T1 - Three-dimensional imaging of magnetic domains N2 - Magnetic domains have been the subject of much scientific investigation since their theoretical existence was first postulated by P.-E. Weiss over a century ago. Up to now, the three-dimensional (3D) domain structure of bulk magnets has never been observed owing to the lack of appropriate experimental methods. Domain analysis in bulk matter thus remains one of the most challenging tasks in research on magnetic materials. All current domain observation methods are limited to studying surface domains or thin magnetic films. As the properties of magnetic materials are strongly affected by their domain structure, the development of a technique capable of investigating the shape, size and distribution of individual domains in three dimensions is of great importance. Here, we show that the novel technique of Talbot-Lau neutron tomography with inverted geometry enables direct imaging of the 3D network of magnetic domains within the bulk of FeSi crystals. KW - Computed tomography KW - Reconstruction algorithm KW - Talbot-Lau neutron tomography KW - Magnetic domains PY - 2010 DO - https://doi.org/10.1038/ncomms1125 SN - 2041-1723 SP - 1 EP - 6 PB - Nature Publishing Group CY - London, UK AN - OPUS4-22609 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hilger, A. A1 - Kardjilov, N. A1 - Lange, A. A1 - Kupsch, Andreas A1 - Hentschel, M. P. A1 - Manke, I. T1 - Neutron darkfield imaging of fiber composites N2 - While X-ray based darkfield imaging with grating interferometers is already widely used, darkfield imaging with neutrons has still a relatively small user community focused mostly on magnetic materials. Here, we demonstrate the application of neutron darkfield imaging byTalbot-Lau type grating interferometry to fiber reinforced plastics. Common carbon and glass fiber composites have been investigated including characteristic damage structures. The darkfield images show a strong signal response caused by fiber delamination, suitable fiber direction, particles, pores and cracks. The basic principles of neutron darkfield imaging applied to fiber composites are highlighted. KW - Neutron radiography KW - Darkfield imaging KW - Talbot-Lau interferometer KW - Fiber composites KW - Non-destructive testing PY - 2021 DO - https://doi.org/10.1515/mt-2020-0103 SN - 2195-8572 SN - 0025-5300 VL - 63 IS - 7 SP - 623 EP - 629 PB - De Gruyter CY - Berlin AN - OPUS4-53077 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, R. A1 - Boenke, T. A1 - Dörfler, S. A1 - Abendroth, T. A1 - Härtel, P. A1 - Althues, H. A1 - Kaskel, S. A1 - Kardjilov, N. A1 - Markötter, Henning A1 - Sintschuk, Michael A1 - Hilger, A. A1 - Manke, I. A1 - Risse, S. T1 - Multimodal Operando Analysis of Lithium Sulfur Multilayer Pouch Cells: An In-Depth Investigation on Cell Component Design and Performance N2 - This study presents an innovative operando analysis of lithium-sulfur (Li/S) multilayer pouch cells, employing a combination of lab-source and synchrotron x-ray imaging to investigate sulfur crystallite dissolution and lithium dendrite formation. By integrating advanced X-ray imaging, impedance spectroscopy, and simultaneous monitoring of temperature and pressure, the research uncovers critical insights into the behavior of active and inactive cell components. The analysis reveals significant degradation increments, primarily driven by side product accumulation and the deterioration of lithium microstructures, which contribute to performance loss over cycling. Additionally, temperature distribution analysis shows a strong correlation between joule heating, polarization resistance, and the observed endothermic processes during crystallization. These findings provide a comprehensive understanding of the mechanistic processes within industrially relevant pouch cells, highlighting opportunities for optimizing Li/S cell designs and advancing high-energy-density battery systems for commercial applications. KW - Current collector perforation KW - Impedance spectroscopy KW - Lthium sulfur batteries KW - Multilayer pouch cells KW - X-ray imaging PY - 2025 DO - https://doi.org/10.1002/aenm.202404256 SP - 1 EP - 12 PB - Wiley VHC-Verlag AN - OPUS4-62436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -