TY - CONF A1 - Wollschläger, N. A1 - Nützmann, Kathrin T1 - What happens during S-corrosion in Fe13Cr in the early stage? N2 - Ferritic alloys containing Cr form Cr5S6 precipitates along grain boundaries in hot SO2 environment. Grain boundary precipitates may influence the steel’s mechanical behavior. Cr5S6 precipitates were reconstructed three-dimensionally using FIB tomography analysis to determine the volume, number, and penetration depth. The volume growth of Cr5S6 precipitates increased only for the initial aging time of 3 h but became constant after 6 h. The number of precipitates increased linearly. T2 - Meeting on Focused Ion Beams in Berlin - FIBiB2017 CY - Berlin, HZB Wannsee Campus, Germany DA - 06.11.2017 KW - Grain boundary corrosion KW - 3D tomography KW - Sulfidation PY - 2017 AN - OPUS4-45061 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koclęga, Damian A1 - Dymek, S. A1 - Radziszewska, A. A1 - Huebner, J. T1 - Optimization of laser treatment parameters of Inconel 686 overlay weld on carbon steel 13Mo4-5 N2 - The work presents the effects of the change of the laser cladding parameters on microstructure, chemical composition and mechanical properties of Inconel 686 overlays (coatings). To obtain the best quality of these coatings the various parameters of laser cladding such as the power density of the laser beam, the laser beam velocity and overlapping ratio of the weld tracks were applied. The substrates were boilers plate made of the 13Mo4-5 steel. Ni - base alloys characterize by the excellent high-temperature corrosion resistance, good strength and good ability to work in aggressive environments. Applied overlays had a proper combination of the metal substrate in particular small amount of Fe. This could be achieved by the reduction of the substrate melting and its dissolution into the overlays. The microstructure, chemical composition of the obtained overlays were investigated by means of a light microscope, a scanning electron microscope (SEM) equipped with the EDS detector. The overlays had cellular-dendritic structure. The variations of the chemical composition (especially Mo, Ni and W ) in the interdendritic and dendritic regions were observed. The interdendritic regions were enriched during solidifications in Mo and W and had lower content of Ni. T2 - METAL 2017 CY - Brno, Czech Republic DA - 24.05.2017 KW - Laser cladding KW - Overlay KW - Chemical composition KW - Inconel 686 PY - 2017 AN - OPUS4-44464 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kotaka, M. A1 - Honma, T. A1 - Shinozaki, K. A1 - Affatigato, M. A1 - Müller, Ralf A1 - Komatsu, T. T1 - Unique growth behavior of ferroelastic beta’-Gd2(MoO4)3 crystals in glasses N2 - An understanding on crystallization behavior and kinetics in glasses is one of the important topics in the glass science and technology. Tsukada et al.1) found an extremely unique and curious phenomenon in the crystallization of multiferroic (ferroelectric and ferroelastic properties) ’-Gd2(MoO4)3 crystals in Gd2O3-MoO3-B2O3 glasses. That is, crystals formed in the crystallization break into small pieces with a triangle prism or pyramidal shape having a length of 50-150 um spontaneously during the crystallization in the inside of an electric furnace, not during the cooling in air after the crystallization. They proposed to call this phenomenon “self-powdering phenomenon”. To the best of our knowledge, such a self-powdering phenomenon has not been observed in the crystallization of any other glasses. To investigate this phenomenon is very important for the glass science and for the preparation of bulk crystallized glasses with ferroelastic crystals. In this work, the preparation of crystallized glasses keeping the original shape is challenged, and the mechanism of self-powdering phenomenon is proposed. Glasses with the compositions of 21Gd2O3-63MoO3-(16-x)B2O3-xTeO2 (mol%) (x=0, 2, 4, 8) such as 21Gd2O3-63MoO3-16B2O3 (GM16B) and 21Gd2O3-63MoO3-8B2O3-8TeO2 (GM8T8B) were prepared using a conventional melt quenching technique. The quenched glasses were heat-treated at some temperatures, and the crystalline phase present in the crystallized samples was identified by X-ray diffraction (XRD) analyses, and the morphology and birefringence of crystals formed were observed using a polarized optical microscope (POM). The densities of GM16B and GM8T8B glasses are 4.76 g/cm3 and 4.91 g/cam3, respectively, and these values are higher than the density of ’-Gd2(MoO4)3 crystal, 4.555 g/cm3. These differences in the density might induce the large stresses in the inside of crystals during the crystal growth. The crystallized glasses of GM16B with ’-Gd2(MoO4)3 crystals do not keep the original glass shape, showing self-powdering phenomenon (breaking into small pieces). However, the crystallized glasses of GM8T8B keep the original glass shape without indicating any self-powdering. It is proposed that the stress at the interface between the glassy phase and ’-Gd2(MoO4)3 crystalline phase might be reduced in GM8T8B glasses containing TeO2 with weak Te-O bonds. T2 - Crystallization 2017 CY - Segovia, Spain DA - 10.09.2017 KW - Glass KW - Crystallization KW - Self-powdering PY - 2017 AN - OPUS4-44403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stephan-Scherb, Christiane A1 - Nützmann, Kathrin T1 - Real time observation of crystallization and growth of corrosion products by energy dispersive X-ray diffraction N2 - Ferritic-martensitic high temperature alloys are widely used as boiler tube and heat exchanger materials in combustion based power plants. All technologies have in common that the applied materials are exposed to different temperatures, process pressures and reactive atmospheres which lead to a change of the material properties and a further degradation of the material. To date corrosion analytics mainly proceeds via the use of various microscopic techniques and the analysis of the corrosion products after the reaction is completed. Comprehensive efforts have been made to study high temperature corrosion by the use of environmental SEM’s or in-situ TEM technologies. The here presented work will show a different approach to study high temperature gas corrosion in a multiple gas atmosphere by energy dispersive X-ray diffraction (EDXRD). For this technique high energetic white X-ray radiation (10-100 keV) was used as radiation source instead of conventional monochromatic radiation. It enables us to study crystallization procedures on short and medium time scales (1 min < t < 24 h) and the collection of Bragg-Signals of the phases of interest as a function of process time. Their occurrence can directly be correlated with thermodynamic and kinetic parameters. A special designed corrosion reactor was used to combine high temperature gas corrosion experiments with the collection of diffraction patter. The crystallization and reaction paths for oxide and sulfide formation was followed in-situ on Fe-Cr and Fe-Cr-Mn model alloys in a hot SO2 containing (T=650 °C) atmosphere. T2 - Gordon Research Conference on High Temperature Corrosion and Protection of Materials CY - New London, NH, USA DA - 09.07.2017 KW - Corrosion KW - In situ diffraction KW - Crystallization PY - 2017 AN - OPUS4-44717 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Höhne, Patrick A1 - Kuchenbecker, Petra A1 - Lindemann, Franziska A1 - Güther, Wolfgang A1 - Rabe, Torsten T1 - Utilization of an ultra sound atomizer for spray granulation of oxide ceramic fine powder N2 - Spray drying based granulation processes aim for flowable granules neither containing voids nor hard shells thus leading to a homogenous microstructure in the green and sinter bodies without strength reducing large pores. The increase of the specific surface area due to the utilization of finer powders as raw materials makes the production of granules of demanded quality more sophisticated. Innovations regarding additives as well as process engineering are therefore required. While conventional spray granulation processes of ceramic materials are based on rotational, one stream or two stream nozzles for nebulization, the investigations in the ZIM project concentrate on the applicability of an ultra sound atomizer unit. A spray dryer comprised of the aforementioned ultra sound atomization unit implemented in a commercial spray dryer (Niro, Denmark) was used as test system. Potential advantages of the ultra sound nebulization are investigated for model systems of alumina, zirconia and a ZTA composite while focusing on solids content, yield, pressability and granule properties (size, size distribution, flowability, shape and microstructure) as well as the final sinter body properties (density, microstructure and flexural strength). First ultra sound spray drying experiments yielded granules with excellent processability. Spray drying of identical slurries, as before tested and optimized for a two stream nozzle atomization process, resulted in a more suitable size distribution for dry pressing (less particles below 20 µm) and a higher yield. Furthermore, sinter bodies produced of ultra sound granules seem to have less large pores and a more homogenous microstructure T2 - 92. Jahrestagung der deutschen keramischen Gesellschaft CY - Berlin, Germany DA - 20.03.2017 KW - Ceramics KW - Spray drying KW - Ultra sound KW - Atomization KW - Microstructure PY - 2017 AN - OPUS4-39588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Otremba, Frank A1 - Sklorz, Christian T1 - Testing of pressurized vessels N2 - The results are based on data1. Figure 3 displays temperatures of the tank wall and of the gas phase over testing time. It can be seen that a complete coating strongly delayed the heating of tank wall and gas phase, whereas the partly coated tanks only had a minor influence on temperature development. There was no significant difference between a half coated and a thirdly coated tank measurable. Figure 4 shows the internal pressure of tanks over testing time. Only the fully coated tank enabled a low pressure over 90 min testing time. Hence, a complete coating is necessary to guarantee the fire safety of hazmat tanks and a partly coating is not sufficient. T2 - Annual Conference on Engineering and Information Technology CY - Nagoya - Japan DA - 29.03.2017 KW - Fire KW - Testing KW - Vessels KW - Dangerous goods PY - 2017 AN - OPUS4-39843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, S. A1 - Hönig, Gerald M. O. A1 - Wagner, M. R. A1 - Müßener, J. A1 - Hille, P. A1 - Teubert, J. A1 - Schörmann, J. A1 - Eickhoff, M. A1 - Hoffmann, A. A1 - Callsen, G. T1 - Tuning of the quantum-confined Stark effect in wurtzite [0001] nanostructures by the internal-field-guarded-active-region design N2 - In this work we eliminate the QCSE without having any special requirements on the growth procedure or the material. Hönig et al. developed the Internal-Field-Guarded-Active-Region Design (IFGARD), which we experimentally investigate in this work based on GaN/AlN nanodiscs (NDs). T2 - Compound Semiconductor Week 2017 CY - Berlin, Germany DA - 14.05.2017 KW - Halbleiterphysik KW - Nanophysik KW - Optoelektronik KW - Piezopolarisation KW - Spontane Polarisation PY - 2017 AN - OPUS4-40174 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Tschiche, Harald Rune A1 - Resch-Genger, Ute T1 - Fluorescence microscopic and spectroscopic monitoring of degradation processes upon polymer ageing N2 - The majority of all routinely used methods to assess polymer aging are based on destructive tests and methods. Early indicators for the deterioration of polymer materials are e.g., physical or mechanical properties like tensile strength, adhesion, brittleness, and color. It is well-known, however, that predominantly chemical changes are the underlying process of the physical changes that occur in organic materials upon aging over time. Typical initial steps during polymer degradation are crosslinking or chain breaking, alteration of autofluorescence, “yellowing” or bleaching caused by the formation of new functional groups. A straightforward strategy towards the sensitive detection and monitoring of chemical changes in the course of polymer aging is based on non-destructive optical measurements. Luminescence techniques, one of the most sensitive spectroscopic methods are the method of choice. Here, we present first results of luminescence-based monitoring of polymer degradation induced by different environmentally relevant weathering factors (e.g. humidity and UV exposure). Our studies include fluorescence spectroscopy as well as spectral scanning confocal fluorescence microscopy and clearly demonstrate the possibility to follow accelerate-aging processes by luminescence detection. T2 - Focus on Microscopy 2017 CY - Bordeaux, France DA - 09.04.2017 KW - Polymer aging KW - Confocal fluorescence microscopy KW - Fluorescence spectroscopy KW - Surface functionalities PY - 2017 AN - OPUS4-40274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tschiche, Harald A1 - Hoffmann, Katrin A1 - Radunz, Sebastian A1 - Schwibbert, Karin A1 - Sameith, Janin A1 - Toepel, Jörg A1 - Resch-Genger, Ute T1 - A Polymeric Nanosensor for Sensing of Broad pH Changes in Biofilm as Tool for the Investigation of Microbial Induced Corrosion N2 - One of today’s major problems in many technical plants as well as fuel tanks is Microbial induced corrosion (MIC), leading to considerable damage and huge financial losses. Successful prevention of MIC requires the localization of first signs of corrosion as well as the identification of factors influencing the corrosion process. Hence, there is a growing need for sensitive and preferably inexpensive tools that enable the early detection of MIC. Of utmost importance are methods, which provide spatially and time-resolved information and allow the determination of corrosion rates at sites of interest for possible prevention of MIC. T2 - First European / 10th German BioSensor Symposium CY - Potsdam, Germany DA - 20.03.2017 KW - Nanoparticel based pH-probes KW - Microbial induced corrosion KW - Imaging PY - 2017 AN - OPUS4-40261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tschiche, Harald A1 - Hoffmann, Katrin A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Resch-Genger, Ute T1 - Determination of degradation products of thermoplastic polyurethane using fluorescent sensors in a model system N2 - Polyurethanes (PU) are formed by polyaddition reaction between diols and diisocyantes. They can be formed utilizing three building blocks, namely a polyol or long-chain diol, a chain extender or short-chain diol, and a diisocyanate. The derived multi-phase block copolymer has thermoplastic properties and is called thermoplastic PU (TPU). This modular approach allows for a variety of alternations yielding a broad range of structural properties and applications. TPUs are based on three main classes of polyols, i.e. polyethers, polyesters, and polycaprolactones. With these different polyols and the ability of changing the ratio of building blocks a variety of material properties can be obtained thus TPUs find numerous applications in e.g. lightweight construction1, insulation, flame retardants, lacquer and glue, as well as medicine. Linear, isocyanate terminated, polyurethane prepolymers prepared from non-equivalent amounts of diisocyanate such as methylene diphenyl diisocyanate (MDI) attached to a polyol are widely used as precursors of the correspondent polymers. Chain-extending reactions with low molecular weight compounds bearing different amounts of active hydrogens enable both linear and crosslinked polyurethane to be formed. Due to TPUs being used in a broad range of applications facing a variety of stress (e.g. mechanical, hydrolytic, thermal, radiative/UV, as well as its combinations) the complexity of possible degradation mechanism is high. A functional group derived from degradation of the bulk matrix can be detected utilizing a suited fluorogenic sensor molecule. There are several fluorogenic dyes known for the application as sensor for amine groups e.g. fluorescamine, pyrylium dyes, deriving a fluorescent signal upon reaction. T2 - ANAKON 2017 CY - Tübingen, Germany DA - 03.04.2017 KW - Bewitterung KW - Polyurethan KW - Functional group detection KW - Polyurethanes PY - 2017 AN - OPUS4-40262 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -