TY - CONF A1 - Ghasem Zadeh Khorasani, Media T1 - Long range influence of boehmite nanoparticles on the nanomechanics of epoxy matrix used in carbon-fiber composites N2 - Boehmite nanoparticles (AlOOH) were recently found to improve properties such as crack resistance, shrinkage and compressive strength in epoxy composites. Concentration and surface modification of boehmite nanoparticles are key factors for abovementioned enhancements. To understand the underlying mechanisms, more detailed research of micro- and nanoscopic mechanical properties is required. The presented study aims to investigate the influence of concentration and surface modification of boehmite on the stiffness of the bulk epoxy by means of AFM-based approaches: Force-Distance curves (FDC) on the sub- microscale and Intermodulation AFM and amplitude-dependent force spectroscopy (ADFS) on the nanoscale. For this purpose, stiffness-maps of epoxy filled with boehmite, with and without surface modification (HAc-boehmite) were obtained by FDC. These measurements showed a slight increase in overall stiffness of composite with increasing the nanoparticle content. The stiffening effect was observed to be intensified with HAc-boehmite. Since the lateral resolution of FDC is not high enough to distinguish nanoparticles, this effect was assumed to be due to the inevitable inclusion of nanoparticles in the measurement. By using Intermodulation-AFM, yielding ADFS stiffness maps with the resolution of <10 nm, we were able to calculate the average stiffness of bulk epoxy without the interference of nanoparticles. It was expected that the stiffness of regions faraway from particles would be equal to neat epoxy. In contrast, the results showed a drastic increase in stiffness of epoxy with increasing boehmite concentration (0, 1, 2.5, and 15%) especially in case of introducing 15wt% HAc-boehmite. Another important observation was formation of a spatial structure with non-homogenous stiffness distribution in bulk epoxy with HAc-boehmite. The underlying mechanisms of described observations are not fully understood yet. One hypothesis is the local increase in crosslinking density which we aim to investigate in our further studies by combining Dynamic Mechanical Thermal Analysis (DMTA) and Intermodulation-AFM. T2 - Frontiers in Polymer Science CY - Seville, Spain DA - 17.05.2017 KW - AFM KW - Boehmite KW - Epoxy nanocomposite PY - 2017 AN - OPUS4-50688 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghasem Zadeh Khorasani, Media T1 - Studies on interphase formation of cured epoxy resin near boehmite surface N2 - The application of inorganic nanoparticles as reinforcement agent for polymer composites is constantly growing. Improving the performance of the material with desirable properties requires understanding of the interaction between polymer chains and nanoparticles and the properties of the interphase as well. Boehmite, a mineral of aluminum with basic unit of AlO(OH), is a novel and promising nanofiller which leads to enhanced performance of polymer composites. It has been recently reported that boehmite nanoparticles have reinforcing effect on epoxy matrix in carbon-fiber composites. It was primarily assumed that these improvements are due to very high Young’s modulus of boehmite particles. However, in our latest study we presented new values for the Young’s modulus of boehmite much lower than those reported earlier. This brings up the importance of interphase properties, e.g. the crosslink density, which can have the dominant role in the overall material property. Nevertheless, due to resolution limitations of conventional nanoprobing approaches, characterization of the interphase between individual particles and matrix is a challenge. In this study, the main goal is to investigate the interphase of the epoxy/boehmite nanocomposites using AFM-based methods. We simplify the three-dimensional nanocomposite system to a two-dimensional horizontally layered sample with a large and easy to access interphase area. For this purpose, 1µm coatings of hydrothermally synthesized boehmite are prepared as the substrate on which the epoxy is later molded and cured. AFM surface potential and force maps were obtained on the cross-sectional cut of epoxy/ boehmite sample. The results show unexpectedly a large interphase area (approx. 1 µm) with different electrical and mechanical properties comparing to bulk epoxy. The average force-distance curves from this region showed more elastic behavior compared to bulk. The underlying mechanism of this influence is not fully understood yet. Thus, further investigation on the interphase region using the novel Nano-IR approach provides more information about the chemical characteristics. Numerical simulation will give complementary information to understand the effect of nanoparticles on the crosslinking density of the interphase. This can be different to bulk epoxy due to either different local temperature gradients or due to a surface selectivity of boehmite towards the monomer molecules. T2 - ICCS20–20th International Conference on Composite Structures CY - Paris, France DA - 04.09.2017 KW - AFM KW - AFM-IR KW - ImAFM KW - Boehmite KW - Epox KW - Nanocomposite KW - Interphase KW - Nanomechanics PY - 2017 AN - OPUS4-50689 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oesch, Tyler T1 - In-situ CT investigation of pull-out failure for reinforcing bars embedded in conventional and high-performance concretes N2 - The use of high-performance concretes holds great promise for many structural applications. This paper investigates the performance of these materials when used in combination with traditional reinforcing bars. An improved understanding of failure during reinforcing bar pull-out from high-performance concretes is needed in order to better predict the embedment length required to develop full reinforcing bar pull-out strength and the required thickness of reinforcing bar cover for adequate corrosion protection. The cracking structures surrounding the reinforcing bars were analyzed using x-ray computed tomography (CT) in order to determine the stress states causing failure. This was accomplished by conducting in-situ reinforcing bar pull-out experiments during CT scanning. A conventional concrete, a high-strength concrete, and a high-strength fiber reinforced concrete were all tested during the experiments. The results of these experiments showed that the levels of brittleness of the different concrete materials had a major impact on the failure mechanisms that they experienced during reinforcing bar pull-out. It was also clear that the specimen geometry and the casting method had a major impact on fiber orientation. The inclusion of fibers within concrete was also found to significantly improve strength and corrosion protection during reinforcing bar pull-out. T2 - 6th Conference on Industrial Computed Tomography CY - Wels, Austria DA - 09.02.2016 KW - Fiber KW - Reinforcing Bar KW - Computed Tomography KW - In-Situ KW - High-Performance Concrete PY - 2016 AN - OPUS4-35521 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stroh, Julia T1 - High resolution in situ monitoring of the initial cement hydration influenced by organic admixtures N2 - Numerous admixtures are used in the building practice to customize the properties of the cement paste during application. The influences of admixtures on the course of cement hydration and formation of hydrate phases have to be considered. Polycarboxylate ether (PCE) based polymeric superplasticizers (SPs) are known to retard the setting of the cement paste. The extent of the retardation differs depending on the molecular structure of the SP. Additionally, the presence of a stabilizing agent (SA) in the cement paste has a retarding side effect on the setting. The initial cement hydration processes and the detailed mechanisms of the retardation influenced by PCEs, as well as their interactions with particular SAs, are insufficiently understood. Up to now, only the results of phenomenological studies were taken into account to describe this retardation process. A detailed structure analysis monitoring the change of the phase composition during the hydration was never applied. Both SP and SA affect the adsorption of the sulphate ions on the clinker particles, causing changes in the formation of ettringite during the initial hydration, and are therefore a crucial part of the setting process itself. Here, the initial hydration of cement influenced by the interaction of SP and SA was monitored in situ by synchrotron X-ray diffraction. The high time resolution of the measurements allowed a continuous detection of the hydrates formed. The hydration was followed from the starting point of water addition and for couple of hours afterwards. The hydration of the levitated cement pellets containing starch as SA was initialized by adding aqueous solutions of different commercial SPs. Changes in the ettringite formation were detected in comparison to the reference hydration of pure cement. T2 - Early Age Concrete: From the Research Lab to the Construction Site CY - Tomsk, Russia DA - 02.06.2015 KW - Portland cement KW - Initial hydration KW - Superplasticizer KW - Stabilizer KW - Synchrotron XRD PY - 2015 AN - OPUS4-35470 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taabache, Soraya T1 - Microfluidic-Assisted Self-Assembly of Dendritic Amphiphiles N2 - The controlled production of supramolecular aggregates formed by the self-assembly of dendritic amphiphiles is of great interest owing to their potential application in the fields of nanotechnology and nanomedicine. Dendritic amphiphiles as building blocks offer the advantage that their structure and size can be precisely tuned through organic synthesis. This synthetic flexibility enables the fine-tuning of the hydrophobic to hydrophilic ratio of the dendritic segments, which mainly controls the morphology of the self-assembled structures. A promising method for the controlled preparation of supramolecular assemblies is based on the use of micromixers.[5,6] Due to their mixing times in the range of milliseconds at the microscale level, the application of such microfluidic systems benefits from a high mixing efficiency, a low mixing time and a reproducible synthesis compared to conventional batch-based techniques such as the solvent injection method or the film hydration method. Herein, we report on the microfluidic-assisted self-assembly of several dendritic amphiphiles and the impact of the mixing parameters on the self-assembly process. T2 - Makromolekulares Kolloquium 2016 CY - Freiburg im Breisgau, Germany DA - 24.02.2016 KW - Dendritic amphiphiles KW - Self-assembly KW - Dendrimersomes KW - Micromixer KW - Microfluidic PY - 2016 AN - OPUS4-35477 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steinborn, Gabriele T1 - Stable aqeous niobium carbide suspensions for production of homogeneous hard materials N2 - Hard materials consist of a hard phase embedded in a metallic binder. In order to achieve high toughness and strength, it is necessary to have a perfect mixing of hard phase and binder, which is mainly achieved by ball milling. Niobium carbide (NbC) has a high potential to substitute tungsten carbide as hard material. The publication presents the development of stable homogeneous and de-agglomerated NbC-dispersions. To prevent agglomeration of the powder, stable suspensions were achieved by surface treatments with the dispersants (PD and HD), which resulted in a charge reversal from a negative to a positive zeta potential. This surface-modified powder guaranteed a stable re-dispersion in the binder suspension. Nickel powder was added as metallic binder. This suspension was suited for 3D-printing. The green samples could be sintered in vacuum or Argon atmosphere. T2 - 91. Jahrestagung der deutschen keramischen Gesellschaft CY - Freiberg, Germany DA - 07.03.2016 KW - Niobium carbide powder KW - Stable suspensions KW - Reduction of agglomerates PY - 2016 AN - OPUS4-35636 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wu, Cheng-Chieh T1 - Inverse finite element adjustment of material parameters from integrated analysis of displacement field measurement N2 - The integration of finite element method (FEM) into the least-squares adjustment presented in is further extended for a joint evaluation of an elastostatic model and displacement field measurement. For linear solids which obey the Hooke's law, the material parameters determination from measurements is being examined. T2 - 32nd Danubia-Adria Symposium on advances in experimental mechanics CY - Starý Smokovec, Slovakia DA - 22.09.2016 KW - Integrated analysis KW - Inverse problem KW - Finite element method KW - Least-squares adjustment KW - Model and measurement based analysis PY - 2015 AN - OPUS4-35648 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Mimicking lizard-like surface structures upon ultrashort laser pulse irradiation of inorganic materials N2 - The wetting behavior of material surfaces can be controlled by surface structures. We functionalized inorganic material surfaces, such as steel, titanium alloy and silicon, to modify the wetting behavior using ultrashort laser pulses (fs- to ps-range). The laser processing was performed by scanning the laser beam across the surface of initially polished flat sample material. A combined experimental and theoretical study of the laser processing parameters (peak fluence, scan velocity, line overlap) allowed the identification of different regimes associated with characteristic surface morphologies (laser-induced periodic surface structures, grooves, micro cones, dimples, etc.). Analyses of the surface using optical as well as scanning electron microscopy allowed the identification of morphologies providing the optimum similarity to the natural skin of lizards. For mimicking skin structures of moisture-harvesting lizards towards an optimization of the surface wetting behavior, additionally, a two-step laser processing strategy was established for realizing hierarchical micro- and nanostructures. In this approach, a laser-generated regular array of small dimples was superimposed (step 2) to the micron-scaled capillaries processed before (step 1). Optical focus variation imaging measurements finally revealed the three dimensional topography of the laser processed surfaces derived from lizard skin structures. The functionality of these surfaces was analyzed in view of wetting properties. T2 - E-MRS 2016 Spring Meeting, Symposium C: "Laser-material interactions for tailoring future applications" CY - Lille, France DA - 02.05.2016 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Steel KW - Lizard KW - Wetting PY - 2016 AN - OPUS4-36047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Tribological properties of femtosecond laserinduced periodic surface structures on metals N2 - Laser-induced periodic surface structures (LIPSS, ripples) were generated on steel and titanium surfaces upon irradiation with multiple linear polarized femtosecond laser pulses (pulse duration 30 fs, central wavelength 790 nm). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning geometry for the processing of large surface areas covered homogeneously by the nanostructures. The irradiated surface regions were subjected to optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM) revealing sub-wavelength spatial periods. The nanostructured surfaces were tribologically tested under reciprocal sliding conditions against a sphere of hardened 100Cr6 steel at 1 Hz using paraffin oil and engine oil as lubricants. After 1000 sliding cycles at a load of 1.0 N, the corresponding wear tracks were characterized by OM and SEM. For specific conditions the laser-generated nanostructures endured the tribological treatment. Simultaneously, a significant reduction of the friction coefficient was observed in the laser-irradiated (LIPSS-covered) areas when compared to the non-irradiated surface, indicating the potential benefit of laser surface structuring for tribological applications. T2 - SPIE Photonics West Conference, Symposium "Laser Applications in Microelectronic and Optoelectronic Manufacturing" (LAMOM) XXI CY - San Francisco, CA, USA DA - 13.02.2016 KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Tribology KW - Friction KW - Wear PY - 2016 AN - OPUS4-36041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kirner, Sabrina T1 - Femtosecond laser-induced periodic surface structures on titanium nitride coatings for tribological applications N2 - Laser-induced periodic surface structures (LIPSS) were generated on titanium nitride (TiN) hardcoating surfaces (deposited on metallic substrates) upon irradiation with multiple linearly polarized femtosecond laser pulses in air (30 fs duration, 790 nm wavelength, 1 kHz pulse repetition rate). The conditions were optimized in a sample-scanning geometry for the processing of large surface areas (5 mm x 5 mm) covered homogeneously by nanostructures with sub-wavelength periods ranging between ~200 nm and 700 nm. For these nanostructures the coefficient of friction was characterized under reciprocating sliding condition against a ball of hardened steel at 1 Hz using different lubricants (regime of mixed friction). After 1000 cycles, the corresponding wear tracks were characterized by optical and scanning electron microscopy. High-resolution energy dispersive X-ray analyzes (EDX) allowed the visualization of chemical alterations within the wear tracks. For specific conditions, the nanostructures endured the tribological treatment. Our experiments provide a qualification of the tribological performance of the fs-LIPSS on TiN surfaces. T2 - E-MRS 2016 Spring Meeting, Symposium C: "Laser-material interactions for tailoring future applications" CY - Lille, France DA - 02.05.2016 KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Tribology KW - Friction KW - Wear KW - Titanium nitride PY - 2016 AN - OPUS4-36042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Naghib-zadeh, Hamid T1 - High-strength and gas-tight ceramic-ceramic joints by RAB composite tapes N2 - Ceramic components with complex shape cannot be produced frequently by usual ceramic forming and sintering processes. Therefore, numerous joining methods were developed and introduced in industrial scale. Nowadays, multi-stage Mo-Mn-process and active brazing are preferentially used, if temperature-stable and gastight joints are required. Unfortunately, both processes involve cost-intensive thermal processes: hydrogenous atmosphere is essential for metallization in Mo-Mn-process and active brazing takes place under vacuum. Thermal processes can be drastically simplified by using Reactive Air Brazing (RAB). Joining under air atmosphere is an interesting alternative, especially to join oxide ceramic components among themselves. So far, main disadvantage of RAB is low strength of join connections. Aim of this investigation was the development of high-strength, thermal shock resistant and gastight ceramic-ceramic joints by RAB. Therefore, - commercial, silver and copper oxide containing RAB soldering composition was modified by addition of ceramic particles with low thermal expansion coefficients (TEC). Hence, thermal misfit between TEC of solder and ceramic components was significantly reduced. - RAB soldering paste was replaced with newly developed RAB composite tapes, produced by ceramic “doctor blade” technology. Thereby, improved potential exist to tailor the brazing layer relating to composition, thickness and thickness uniformity. Gastight alumina-alumina, alumina-zirconia and zirconia-zirconia joints with strongly improved strength were produced by novel composite tapes. No strength degradation of joints was observed after thermal cycling up to 700°C. T2 - Jahrestagung der Deutschen Keramischen Gesellschaft (DKG) 2016 CY - Freiberg, Germany DA - 07.03.2016 KW - Brazing KW - Compsite tapes KW - Ceramic-ceramc joints PY - 2016 AN - OPUS4-36114 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spranger, Holger T1 - THz-ToF techniques for the detection of inherent discontinuities in dielectric materials based on SAFT N2 - The ability to penetrate dielectric materials makes T-rays attractive to reveal discontinuities in polymer and ceramic materials. Changes of travelling time (ToF) and pulse shape due to the interactions of THz pulses with the dielectric material and its inherent discontinuities can be observed. 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. T2 - 7th International Workshop on Terahertz Technology and Applications CY - Kaiserslautern, Germany DA - 15.03.2016 KW - Terahertz synthetic aperture dielectric materials PY - 2016 AN - OPUS4-36221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spranger, Holger T1 - THz-ToFD Tomography with Synthetic-Aperture-Aperture N2 - Terahertz-radiation (T-ray) are electromagnetic waves within a frequency range between 0,3 to 6 THz. T-rays are nonionising! They penetrate plastic, paper, ceramic and fabric. It is promising to use T-Rays for CT-applications to reveal uncertainties in dielectric materials. T2 - 8. THz-PhD-meeting CY - Marburg, Germany DA - 06.08.2013 KW - Terahertz Tomography synthetic aperture PY - 2013 AN - OPUS4-36223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maurer, G. T1 - High-pressure gas solubility in mixtures with one compound being an „alternative“ solvent N2 - The term „Alternative Solvents“ often refers to ionic liquids (ILs), mainly to distinguish these substances from traditional (i.e., molecular) solvents. In applications, any „alternative“ is required to perform better than something that is proven and tested. To bring ILs into practical use, availability and costs are the fundamental points to be addressed. There are two ways to proceed: ▬ tailoring a molecule, implanting the expected characteristics advantage: optimization of the targeted performance possible risks: outcome not always foreseeable, costly and time-intensive (“trial and error“) ▬ to target on mixtures of well-characterized ILs with molecular solvents advantage: substance characteristics are known, less costly, less time-consuming, mixture composition another tunable parameter risks: the same but with less impact For the basic engineering of technical processes, knowledge of phase equilibria, particularly of mixtures, over a broad (p,T) range is mandatory. This contribution reports on recent experimental results from our laboratory: ▬ the solubility of CO2 in a mixture of water and [bmim][CH3SO4] ▬ the solubility of CO2 in a mixture of methanol and [bmim][PF6] T2 - EUCHEM 2014 5th Conference on Molten Salts and Ionic Liquids CY - Tallinn, Estonia DA - 06.07.2014 KW - Ionic liquids KW - Gas solubility KW - Henry's constant PY - 2014 AN - OPUS4-35944 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kalies, G. A1 - Rockmann, R. T1 - Reliable information on solids from liquid-Phase adsorption N2 - For the characterization of disperse and porous solids, usually single gas adsorption(GA) is employed. In the case of liquid adsorption (LA), the extraction of information on solids immediately becomes a more sophisticated matter since information on geometric as well energetic parameters of the solids is both superposed by liquid-mixture effects and displayed in excess terms. We have to ask if reliable solid parameters can be also obtained from LA isotherms. The enlarged data bank of gas and liquid adsorption measurements enables us to change systematically solid parameters (e.g., the pore width of MCM-41, the pore entrances of SBA-16, chemical heterogeneity) and to study in this way the influence of solid parameters on LA. T2 - The FOA 10, 10th International Conference on Fundamentals of Adsorption CY - Awaji Island, Japan DA - 23.05.2010 KW - porous solids KW - gas adsorption KW - excess isotherms PY - 2010 AN - OPUS4-35945 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nguyen, Thi Yen T1 - Direct evidence of polyamorphism in paracetamol N2 - While polymorphism is a common phenomenon in the crystallization processes of organic compounds, polyamorphism has gained importance only recently. Using sophisticated sample environments and applying in situ scattering methods and vibrational spectroscopy, the complete crystallization process of organic compounds from solution can be traced and characterized. Diffuse scattering from amorphous intermediates can be investigated by analyzing the atomic pair Distribution function (PDF) to gain further insights into molecular pre-orientation. The crystallization behavior of Paracetamol was studied exemplarily under defined, surface-free conditions. Based on the choice of the solvent, the formation of different polymorphs is promoted. The thermodynamically stable form I and the metastable orthorhombic form II could be isolated in pure form directly from solution. For both polymorphs, the crystallization from solution proceeds via a distinct amorphous precursor phase. PDF analyses of these different amorphous states indicate a specific pre-orientation of the analyte molecules introduced by the solvent. The resulting crystalline polymorph is already imprinted in these proto-crystalline precursors. Direct experimental evidence for the polyamorphism of paracetamol is provided. T2 - Annual CM1402 crystallize COST meeting CY - Coimbra, Portugal DA - 06.04.2016 KW - Paracetamol KW - Crystallization KW - In situ analysis KW - Active pharmaceutical ingredient (API) PY - 2016 AN - OPUS4-35873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Electron irradiation of biomolecules under physiological conditions: Experimental realization and microdosimetric calculations N2 - In the last years, secondary low-energy electrons (LEE) emerged as important, if not predominant, reductive pathway in ionizing damage of biomolecules. These electrons are created in copious amount as result of inelastic scattering of high energy radiation at water. Until now, all experiments the quantification of the effects of LEEs on the biomolecular damage was either performed in vacuum with LEE sources or with DNA on surfaces in humid atmosphere. We present a new experimental setup to irradiate biomolecules with electrons under physiological conditions. In combination with monte carlo simulations this setup makes it possible to determine microdosimetric quantities for biomolecules in liquid environment under electron irradiation. This opens up new possibilities in radiation research to access the LEE damage under well defined physiological condition, for more complex systems, such as DNA-Protein complexes and even living cells. T2 - 14th International Congress of the International Radiation Protection Association CY - Cape Town, South Africa DA - 09.05.2016 KW - DNA KW - Dosimetry KW - Microdosimetry KW - Geant4 KW - Low energy electrons KW - Radicals KW - Radiation damage KW - Polymers PY - 2016 AN - OPUS4-36399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Madkour, Sherif T1 - Evidence of a Three-Layred Structure in Ultrathin PVME and PVME-PS Blend Films by Nanosized Relaxation Spectroscopy N2 - In the course of miniaturizing modern technology down to the molecular scale, much remain unknown about the materials behavior and the deviations from the bulk that might arises from confinement effects. Here, a combination of nano-sized relaxation spectroscopies (Broadband dielectric spectroscopy (BDS) and Specific heat spectroscopy (SHS); employing AC nanochip calorimetry) were utilized to investigate the glassy dynamics of ultra-thin films of Poly (vinyl methyl ether) (PVME) and of blends PVME / Polystyrene (PS) 50:50 wt-%,, which are miscible in bulk (thicknesses: ca. 8 nm – 160 nm, film thickness was controlled by ellipsometry, film topography by AFM). Both methods are sensitive to different probes; where SHS senses entropy fluctuations while BDS measures dipole fluctuations. For BDS measurements, a recently developed nano-structured electrode sample arrangement is employed, where ultra-thin films are spin-coated on an ultra-flat highly conductive silicon wafer, sandwiched between a wafer with nanostructured SiO2 nano-spacers with heights between 35 nm and 70 nm. For PVME films, two thickness independent processes were observed and interpreted to be the α-processes of a bulk-like layer and a process due to an absorbed layer to the substrate. This adsorbed layer further undergoes a confinement effect that results in the localization of the segmental dynamics, which results in an Arrhenius-like temperature dependence. A detailed analysis of the dielectric strengths of both processes reveals that the thickness of the adsorbed layer decreases with increasing temperature, while that of the bulk-like layer increases. For the blend system, by measuring the dynamic Tg in dependence of the film thickness, SHS showed that the Tg of the whole film was strongly influenced by a nanometer-thick surface layer at the polymer/air interface due to a self-assembling process. The dynamic Tg obtained from the SHS measurements decreased with decreasing film thickness. On the other hand, BDS measurements showed a completely different behavior. At high temperatures, the temperature dependence of the relaxation times of the films follows that of bulk-like PS/PVME; obeying the VFT-law. With decreasing temperature, the temperature dependence deviates from the VFT to an Arrhenius law; where the apparent activation energy decreases with decreasing film thickness. This is the first example where confinement induced changes were observed by BDS for ultra-thin films. All results were analyzed in detail in a comprehensive discussion. T2 - 14. Lähnwitzseminar on Calorimetry CY - Rostock-Warnemünde, Germany DA - 05.05.2016 KW - Ultra-Thin films PY - 2016 AN - OPUS4-36477 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sentker, K. A1 - Yildirim, Arda T1 - Columnar axial orientation of discotic liquid crystals in nanoporous solids N2 - Successful implementation of an optical polarimetry measurement setup. Due to wall anchoring interactions HAT6 embedded in an untreated alumina membrane exhibits a radial orientation for pore sizes in between 30 nm and 80 nm. Embedded in large membranes, pore size of 180 nm, HAT6 forms the favored hexagonal columnar phase along the pore axis. T2 - 80. Jahrestagung der DPG und DPG-Frühjahrstagung CY - Regensburg, Germany DA - 06.03.2016 KW - Discotic Liquid Crystals KW - Nanoconfinement KW - Orientation PY - 2016 AN - OPUS4-36479 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Walter, Astrid T1 - EU-Projekt HOMER, home made explosives (HMEs) and recipes characterisation N2 - Das EU-Projekt HOMER befasst sich mit den sogenannten Home Made Explosives (HMEs) und frei verfügbaren Rezepten für deren Herstellung. Diese Selbstlaborate spielen in der heutigen Zeit vor allem im Zusammenhang mit terroristischen Aktivitäten eine bedeutende Rolle. Informationen zu HMEs und ihrer Herstellung werden einfacher denn je über das Internet verbreitet. Hier knüpft das im 7. EU‑Forschungsrahmenprogramm finanzierte Projekt an und bezweckt, die im Internet verfügbaren Quellen auszuwerten und so die Informationslage für Sicherheitskräfte und Ermittlungsbehörden zu verbessern. Im Rahmen des Projektes wird eine automatisierte Suche von Rezepten im Internet entwickelt. Die gefundenen sowie die im Projekt generierten Informationen über HMEs sollen im Endergebnis in Form einer Software (Knowledge Management Platform) informationstechnisch nutzbar gemacht werden. Diese Datenbank soll auch für mobile Geräte zur Verfügung stehen. Der Schwerpunkt der Projektbeteiligung des Fachbereichs 2.3 Explosivstoffe der BAM liegt in der Bewertung der Rezepturen und der auf ihrer Grundlage hergestellten Laborate. Es wurden HMEs entsprechend der vorgefundenen Rezepte und unter Beachtung aller notwendigen Sicherheitsvorkehrungen hergestellt und anschließend sicherheitstechnisch geprüft und bewertet. Dabei wurden sowohl Handhabungsparameter wie die Empfindlichkeiten gegen Schlag, Reibung und thermische Einflüsse ermittelt, als auch die Leistungsparameter wie Detonationsgeschwindigkeit und Luftstoßdruckwirkung gemessen. Die gewonnen Erkenntnisse fließen in die genannte Datenbank ein und sollen beispielsweise Einsatzkräften vor Ort helfen, angemessene Schutzabstände zu ermitteln. Auch das Personal in Laboren der Kriminalämter profitiert von der zusammengetragenen Information über HMEs bei der Analyse von unbekannten Explosivstoffspuren. T2 - 14. BAM-PTB-Kolloquium zur chemischen und physikalischen Sicherheitstechnik CY - Berlin, Germany DA - 14.06.2016 KW - Homemade explosives KW - Explosivstoffe KW - TATP KW - Ammoniumnitrat PY - 2016 AN - OPUS4-36594 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulla, Hannes T1 - In situ investigation of mechanochemical reactions with PXRD and Raman spectroscopy - cocrystals of pyrazinamide with dicarboxylic acids N2 - - Cocrystal formation of pyrazinamide with dicarboxylic acids proceeds either directly or via a crystalline intermediate. - Two new crystal structures were discovered by in situ investigations. T2 - ICS 2016 CY - Granada, Spain DA - 30.05.2016 KW - In situ KW - Mechanochemie KW - XRD KW - Cocrystal PY - 2016 AN - OPUS4-36620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Feldkamp, Martin T1 - Heat Flux from Wood Filled Impact Limiter under Fire Conditions N2 - Packages for the transport of high-level radioactive material must withstand severe hypothetical accidents. Regulatory test conditions shall cover these severe accident conditions and consist of mechanical tests and a following thermal test. To withstand the mechanical tests heavy weight packages are often designed with impact limiters consisting of wood encapsulated in steel sheets. The thermal test is defined precisely in the IAEA-regulations as a 30 minute fully engulfing 800 °C fire. After the fire phase a pre-damaged impact limiter might continue burning or smouldering and influence the cask thermal behaviour with its energy release. The energy transferred from the impact limiter to the cask is of importance for the safety of transport packages. A full-scale fire test with an impact limiter of 2.3 m in diameter and filled with spruce wood was designed and performed. The impact limiter continued burning for 3 days. Energy transfer and temperature measurements were performed. T2 - 9th International Scientific Conference - wood & fire safety 2020 CY - Online meeting DA - 02.11.2020 KW - Fre KW - Smouldering KW - Wood PY - 2020 AN - OPUS4-51517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dittmann, Daniel T1 - Aktivkohlecharakterisierung von GAK-Filtern bei unterschiedlichen Laufzeiten N2 - Eine umfangreich ausgestaltete Trinkwasseraufbereitung als Multibarrieren-System ist notwendig, wenn das Rohwasser direkt aus Fließgewässern entnommen wird (z. B. für das Mülheimer Verfahren). Eine der Barrieren wird, als gezielte Behandlungs- oder Sicherheitsstufe, oft als Filter mit granulierter Aktivkohle (GAK-Filter) realisiert. Ihre Standzeit kann bei geringer Wasserbelastung (DOC < 2 mg/L), z. B. bei der Landeswasserversorgung Langenau, bis zu 5 Jahre betragen. Bei Rohwasser mit höherem Organikgehalt (DOC > 7 mg/L), wie bei der Nordwasser in Rostock, wird hingegen mindestens alle drei Jahre die GAK in den Filterkolonnen ausgetauscht. Die Rest-Adsorptionskapazität der GAK kann durch verschiedene Verfahren abgeschätzt werden, ist aber nach wie vor Gegenstand aktueller Forschung. Die weitergehende Charakterisierung der beladenen GAK kann hierbei helfen. Auf dem Poster sollen erste Ergebnisse zu den in Langenau und Rostock eingesetzten Aktivkohlen präsentiert werden. Hierzu wurden die frischen und nach unterschiedlichen Laufzeiten beladenen GAK untersucht. Die Zusammensetzung der Anorganik und der adsorbierten Organik, welche mittels Zersetzungs¬gasanalyse charakterisiert wurde, zeigt deutliche Unterschiede. Bspw. nimmt der Calcium-Gehalt der GAK in Langenau kontinuierlich zu, wohingegen dieser in den Proben aus Rostock mit zunehmender Laufzeit zurückgeht. Umgekehrt verhält es sich mit der Organik: Die GAK aus Rostock zeigen Hinweise auf biologische Besiedelung, während diese in Langenau trotz längerer Filterlaufzeit auszubleiben scheint. T2 - 4. Mülheimer Wasseranalytisches Seminar (MWAS2020) CY - Mülheim an der Ruhr, Germany DA - 16.09.2020 KW - Thermogravimetrie KW - Trinkwasser KW - Wasseraufbereitung KW - Aktivkohle PY - 2020 AN - OPUS4-51433 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg T1 - Novel Technique for On-Line Monitoring of the Curing Process of Fiber Reinforced Polymer Composites N2 - A specially designed experimental set up has been integrated into a commercially available FT IR Spectrometer for ATR experiments on Epoxy Systems. Representative data of far infrared spectra measured during the curing process at different temperatures of an epoxy system will be presented in dependency of the curing situation. The experiments and the selected set up are discussed to demonstrate its potential for future monitoring and ageing control applications during a manufacturing process of polymer composites. T2 - 45. International Confercene on infrared, milimeter and terahertz waves CY - Online meeting DA - 08.11.2020 KW - Far-infrared spectroscopy KW - Curing Monitoring PY - 2020 UR - https://live-irmmwthz.pantheonsite.io/technical-program AN - OPUS4-51649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayerlein, Bernd T1 - Focused ion beam techniques beyond the ordinary - Methodological developments within ADVENT N2 - This poster presents the focused ion beam preparation methodologies developed within the framework of the EU funded EURAMET project ADVENT (Advanced Energy-Saving Technology). It summarises the key breakthroughs achieved for various in situ investigation techniques, e.g. in situ experiments at the Synchrotron facility BESSY II (IR-SNOM and XRS), TEM and SMM instrumentation. The created experimental devices from diverse thin-film semiconductor materials paved the way to dynamic structural studies bearing the potential to determine nanoscale correlations between strain and electric fields and, moreover, for the fundamental development of new in situ capabilities. N2 - Dieses Poster zeigt die FIB Präparationstechniquen, die im Rahmen des EU-finanzierten EURAMET-Projekts ADVENT (Advanced Energy Saving Technology) entwickelt wurden. Es fasst die wichtigsten Errungenschaften zusammen, die für verschiedene in situ Untersuchungstechniken erzielt wurden, z.B. situ-Experimente in dem Synchrotronring BESSY II (IR-SNOM und XRS), in situ TEM Experimente und für die SMM Technik. Die experimentellen Probenstrukturen, die aus verschiedenen Dünnschicht-Halbleitermaterialien erzeugt wurden, ebneten den Weg für dynamische Strukturstudien, die das Potenzial haben, nanoskalige Korrelationen zwischen Dehnung und elektrischen Feldern zu bestimmen und darüber hinaus neue in situ Messmethoden zu entwickeln. T2 - Final Meeting CY - Online Meeting DA - 30.06.2020 KW - FIB KW - Sample preparation KW - In situ KW - TEM KW - AFM PY - 2020 AN - OPUS4-51606 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Linberg, Kevin T1 - Taking Fluorine Interaction to the Extremes using XRD and DFT Simulations N2 - This work aims to investigate the role of F-F and F-π interactions in dictating structural and mechanical properties, through a combination of X-ray powder diffraction and dispersion-corrected density functional. As no benchmarking data exist for F-dominating organic system, we first assess how different functionals affect the mechanical properties of the material. T2 - CRC 1349 Fluorine-Specific Interactions Symposium CY - Online meeting DA - 27.09.2021 KW - High Pressure KW - Fluorine Interaction KW - Hexafluorobenzen KW - Density Functional Theory PY - 2021 AN - OPUS4-53654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lagleder, Michaela T1 - Materialographische Untersuchungen an Bauteilen N2 - Eine Grundanforderung an Bauteile ist deren mechanische Integrität, die als Festigkeit (globale Bauteilbeanspruchung) bzw. Tragfestigkeit (lokale Beanspruchung) zu verstehen ist. Die Bauteilfestigkeit wird wesentlich durch das Materialgefüge bestimmt und kann über die Prüfung der Härte des Grundwerkstoffes lokal erfasst werden. Bei Bauteilverbindungen (z.B. Schweißnähte) ist zudem der Übergangsbereich zwischen den Fügeteilen von besonderem Interesse, bei Passungen oder Gleitlagern sind zudem geringe Rauheiten erforderlich, die oft durch mechanische Oberflächen-bearbeitung realisiert werden. Leichtbauweisen können sowohl über hochfeste Stahllegierungen bei geringem Materialeinsatz als auch über Aluminiumlegierungen realisiert werden. Für unterschied-liche Grundwerkstoffe (X2CrNiMo18-14-3, Co-Cr-W-Ni, AlSi10Mg, X5CrNi1810, ferritische Schweiß-nähte) werden an Quer- und Oberflächenschliffen Änderungen im Gefüge, morphologische Besonderheiten, Härteverläufe sowie Änderungen in den Rauheitskennwerten betrachtet, wie sie im Ergebnis mechanischer Oberflächenbearbeitung, bedingt durch den Herstellungsprozess, die Beanspruchung oder den Fügeprozess auftreten. Zur Validierung der Härtebestimmung wurde ein Laborvergleichsversuch an einer MPA-zertifizierten Härtevergleichsplatte und einer 100Cr6 Referenzprobe durchgeführt, den drei bzw. fünf der insgesamt fünf Teilnehmer bestanden. T2 - 55. Materialographie-Tagung CY - Online meeting DA - 29.09.2021 KW - Gleitlinien KW - Rauheit KW - Härteverlauf Schweißnaht KW - Laborvergleich Härte KW - Aluminium PY - 2021 AN - OPUS4-53503 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Netzband, Olivia T1 - Materialographische Untersuchungen an Funktionsschichten N2 - Oberflächenmodifizierte Grundwerkstoffe, insbesondere solche mit funktionellen Schichten, sind in unterschiedlichsten Branchen und Anwendungen anzutreffen. Es werden Quer- und Kalottenschliffe von Einfach- und Mehrschichtsystemen mit Beispielen aus dem Bereich des Korrosions- und Verschleißschutzes sowie dekorativer Anwendungen auf unterschiedlichsten Grundwerkstoffen (X5CrNi1810 Stahl, 100Cr6 Stahl, Hartmetall, ABS und Pappe) vorgestellt. Ebenso vielfältig wie die Grundwerkstoffe sind die Oberflächenmodifizierungen mit Funktionsschichten auf Basis von Nitrierungen, Hartstoffen, diamantähnlichem Kohlenstoff, Metallisierungen und Lackschichten mit Interferenzpigmenten. Neben der Identifikation von Schichtdefekten gilt das Hauptaugenmerk der materialographischen Analyse der Erfüllung der Schichtdickenspezifikation und der Bewertung der Homogenität der Schichtdicke auch bei kritischen Geometrien. Zur Validierung der Schichtdicken- bzw. Längenbestimmung im Querschliff wurde ein Laborvergleichsversuch mit einem Nickel-beschichteten Kupferdraht durchgeführt, den alle der 10 Teilnehmer bestanden. T2 - 55. Materialographie-Tagung CY - Online meeting DA - 29.09.2021 KW - Metallographie KW - Schichtdicken KW - Korrosion KW - Kalottenverfahren PY - 2021 AN - OPUS4-53504 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rautenberg, Max T1 - The Effect of Fluorine on Catalysts for the Oxygen Reduction Reaction obtained from Metal Organic Frameworks N2 - The oxygen reduction reaction (ORR) – an important reaction in electrochemical devices, such as fuel cells - is characterized by its sluggish kinetics and therefore requires catalysis. The industry currently relies on platinum as a catalyst, although it is scarce and expensive, hindering the commercial breakthrough of fuel cells in automotive applications. Platinum-free catalysts on basis of nitrogen- and metal doped carbons (NMCs) and fluorinated carbons are promising materials to replace platinum-based catalysts for the ORR. In this work we prepared six metal-organic frameworks (MOFs) by mechanical ball mill grinding and studied their formation by in-situ powder X-ray diffraction. Furthermore, the samples were carbonized under controlled conditions (900°C, 1h, N2-atmosphere) to yield carbon materials, that were employed in ORR-electrocatalysis. The effect of Co-doping and fluorination was systematically studied and outstanding ORR activity was found for the catalyst prepared from the Co-doped fluorinated ZIF-8. T2 - International Symposium on Fluorine-specific interactions CY - Berlin, Germany DA - 27.09.2021 KW - PGM-free catalyst KW - Oxygen Reduction Reaction KW - Mechanochemistry KW - MOFs PY - 2021 AN - OPUS4-53533 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rautenberg, Max T1 - Fluorination and co-doping of ZIF-8 by ball mill grinding for efficient oxygen reduction electrocatalysis N2 - The oxygen reduction reaction (ORR) is a common process in a variety of electrochemical devices, like fuel cells and metal air batteries. The sluggish kinetics of the ORR require an electrocatalyst to pass this bottleneck.[1] Currently, the most used catalytical systems are platinum-based, with several drawbacks, such as the high cost, low availability, and deactivation by CO poisoning.[2] Efforts are made to develop efficient, durable and low cost catalysts to promote the commercialization of fuel cells. Non-precious metal catalysts are promising candidates for efficient ORR catalysis. It has been shown that pyrolyzing metal organic frameworks (MOFs) under inert conditions yields carbon-rich materials, with evenly distributed metal sites, which possess promising electrocatalytic activity.[3] One widely used type of MOF as ORR catalyst precursors is the zeolitic imidazole framework (ZIF) where metal cations are linked through imidazole-based ligands. Their porous nature is partially retained after carbonization, making MOFs very suitable precursor materials. Herein we report the mechanochemical synthesis and structural analysis of Co-doped ZIF-8 (Zn), as well as two polymorphs (dense and prorous) of fluorinated Co-doped CF3-ZIF-8 (Zn). The samples showed electrochemical performance comparable to platinum after carbonization for 1 h at temperatures ranging between 850 – 1000°C. T2 - XXV General Assembly and Congress of the International Union of Crystallography - IUCr 2021 CY - Prague, Czech Republic DA - 14.08.2021 KW - PGM-free catalyst KW - Oxygen Reduction Reaction KW - Mechanochemistry KW - MOFs PY - 2021 AN - OPUS4-53535 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rautenberg, Max T1 - Synthesis and characterization of fluorinated Co-Zn-Zeolitic imidazole frameworks for catalysis of the oxygen reduction reaction N2 - The oxygen reduction reaction (ORR) is a common process in a variety of electrochemical devices, like fuel cells and metal air batteries. The sluggish kinetics of the ORR require an electrocatalyst to pass this bottleneck.[1] Currently, the most used catalytical systems are platinum-based, with several drawbacks, such as the high cost, low availability, and deactivation by CO poisoning.[2] Efforts are made to develop efficient, durable and low cost catalysts to promote the commercialization of fuel cells. Non-precious metal catalysts are promising candidates for efficient ORR catalysis. It has been shown that pyrolyzing metal organic frameworks (MOFs) under inert conditions yields carbon-rich materials, with evenly distributed metal sites, which possess promising electrocatalytic activity.[3] One widely used type of MOF as ORR catalyst precursors is the zeolitic imidazole framework (ZIF) where metal cations are linked through imidazolebased ligands. Herein we report the mechanochemical synthesis, structural analysis and of Co-doped ZIF-8 (Zn), as well as its fluorinated counterpart Co-doped CF3 -ZIF-8 (Zn). The samples showed electrochemical performance comparable to platinum after carbonization for 1h at temperatures ranging between 850 – 1000°C. T2 - 15th International conference on materials chemistry (MC15) CY - Online meeting DA - 12.07.2021 KW - PGM-free catalyst KW - Oxygen Reduction Reaction KW - Mechanochemistry KW - MOFs PY - 2021 AN - OPUS4-53539 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Carstensen, Niels T1 - Generation of Tribosystems by Additive Surface Treatment on Tool Steel Substrate N2 - Laser implantation aims at reducing friction and wear on highly stressed surfaces in forming processes. Especially the hot stamping process that is used as a resource efficient process for manufacturing geometrical complex and high-strength structures, exhibits severe wear and high friction during the forming operation. The laser implantation process addresses this problem by combining two different approaches (surface modification and surface structuring) in surface technology by creating elevated, highly wear-resistant micro-features to influence the tribological performance. Pure TiB2 implants have shown to reduce tool-sided wear significally and improve the part formability by reducing local necking in deep drawing tests. Within the scope of this work, TiB2-TiC and TiB2-TaC hard material mixtures are implanted on X38CrMoV5-3 hot work tool steel. The aim is to investigate how the implant material properties can be influenced by the application of different mixing ratios of hard material mixtures under the specific variation of the process parameters. Distinct implant formations are tested on a novel test apparatus to examine the influence on the tribological properties. From the analyses of the implant properties by hardness measurements, light microscopic images, EDX and XRD analyses process parameter ranges are identified to produce defect-free dome- and ring-shaped implants. The specific process parameters (pulse power, pulse duration, mixing ratio and coating thickness) can be used for the determination of the implant geometry (height, width and depth). The tribological tests exhibit improved friction and wear properties. Based on these results, a tribosystem manufactured by this additive surface treatment technology shows great potential to enhance the effectiveness of the hot stamping process. T2 - Friction 2021 CY - Sankt Augustin, Germany DA - 18.11.2021 KW - Laser implantation KW - Surface modification KW - Additive surface treatment KW - Hot stamping KW - Tool steel PY - 2021 AN - OPUS4-53809 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Feiler, Torvid T1 - Tuning the mechanical flexibility of organic molecular crystal by polymorphism for flexible optical waveguide N2 - Crystalline molecular materials are usually brittle and are prone to break into pieces upon external mechanical force. This fragility poses challenges for their application in next-generation technologies, including sensors, synthetic tissues, and advanced opto-electronics. The recent discovery of mechanical flexibility in single crystals of molecular materials has solved this issue and enable the design of smart flexible device technologies. Plastic crystals can be deformed permanently. This behavior is based on anisotropic molecular arrangements and the existence of facile slip planes which allow a permanent motion within the lattice. In contrast, elastic crystals can be deformed, but regain the original structure when the force is removed. This phenomenon is related to energetically isotropic molecular packing. Here we report 4-bromo-6-[(6-chlorolpyridin-2-ylimino)methyl]phenol (BCMPMP) as a promising candidate for future waveguide technologies. It turns out that BCMPMP has two different polymorphs with distinct optical and mechanical properties. Form I crystallizes in the orthorhombic space group Pca21 and shows brittle behavior. This structure exhibit very weak emission at 605 nm (λex = 425 nm) together with a low fluorescence quantum yield (Φ = 0.4 %). On the other hand, form II (monoclinic space group P21/c) has a large plastic regime and a bright emission at 585 nm (λex = 425 nm; Φ = 8.7 %). Based on its improved mechanical and optical properties, form II was explored as a bendable optical waveguide. Light was successfully propagated through a straight-shaped and mechanically deformed BCMPMP crystal. Depending on the light source, active or passive waveguiding could be achieved. So BCMPMP can also be used as a flexible wavelength filter. T2 - International School of Crystallography in Erice CY - Online meeting DA - 30.05.2021 KW - Flexible crystals KW - Polymorphism KW - Waveguide PY - 2021 AN - OPUS4-53905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völker, Christoph T1 - Presenting “SLAMD” - The Sequential Learning App for Materials Discovery N2 - Environmentally friendly alternatives to cement are created through the synthesis of numerous base materials. The variation of their proportions alone leads to millions of materials candidates. Identifying suitable materials is very laborious; traditional systematic research in the laboratory consumes a lot of time and effort. Sequential learning (SL) potentially speeds up the materials research process despite limited but highly complex available information. SL does not make direct predictions of material properties but ranks possible experiments according to their utility. The most promising experiments are prioritized over dead-end experiments and experiments whose outcome is already known. Our work has shown that SL seems to be promising for cement research. So far, research has mainly focused on materials whose synthesis is faster and whose material properties require less time for development or characterization (allowing many successive experiments). Contrarily, in the case of binders, SL is only useful if few experiments lead to the desired goal, as for example, the determination of the compressive strength alone typically requires 28 days. In research practice, experimental designs and the availability of resources often determine which data can be used - for example, when some laboratory resources are not available or deemed irrelevant to a task. As a result, new research scenarios are constantly emerging, each of which requires to demonstrate SL’s performance. We are presenting the SLAMD app to facilitate the exploration of SL methods in numerous research scenarios. The app provides flexible and low-threshold access to AI methods via intuitive and interactive user interfaces. We deliberately pursue a software-based research approach (as opposed to code-, or script-based). On the one hand, the results are more comprehensible since we refer to a common (code) basis (’reproducible science’). On the other hand, the methods are easily accessible to all which accelerates the knowledge transfer into laboratory practice. T2 - DGM Materials Week 2021 CY - Online meeting DA - 07.09.2021 KW - Sequential learning KW - Scientific software KW - Alcali activated binders PY - 2021 AN - OPUS4-54128 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Höhne, Patrick T1 - Limits of computer tomography aided characterization of different types of porous ceramic materials N2 - Ceramics with open porosity are attractive materials in many fields of applications covering medicine, catalysis, and filtration. Manifold technologies to produce porous ceramics are available, e.g. foaming and replica processes, resulting in various microstructures. Development and manufacturing of new materials is accelerating, while crucial characterization is becoming increasingly difficult and conventional measurements lack the desired speed. Computed tomography (CT) offers the possibility to three-dimensionally characterize entire samples with minimal sample preparation, while its main advantage is that it is non-destructive. Still, the assessment of quantitative results from CT measurements is not trivial. The poster presents CT characterizations of newly developed as well as commercially available openly porous ceramic samples. Properties such as porosity, permeability or pore characteristics were measured conventionally and compared to results calculated from CT-measurements using the commercial software VG StudioMax. The determined differences between measured and calculated values are presented and application areas as well as limits of the CT characterization are evaluated. T2 - Jahrestagung der Deutschen keramischen Gesellschaft 2021 CY - Online Meeting DA - 19.04.2021 KW - Ceramic KW - Porosity PY - 2021 AN - OPUS4-52724 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolmangadi, Mohamed Aejaz T1 - Molecular dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase separation N2 - For the first time, dielectric and calorimetric investigations of a homologous series of Janus polynorbornenes with rigid main backbones and flexible −Si(OR)3 side groups of differing length alkyl chains (R = propyl, butyl, hexyl, octyl, and decyl) is reported. Generally, this class of polymers has some potential for applications in the field of gas separation membranes. Two dielectrically active processes are observed at low temperatures, denoted as β- and α-relaxation. The former can be assigned to localized fluctuations, while the latter is related to the glassy dynamics of the flexible −Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain-rich and backbone-rich domains. This is confirmed through temperature-modulated differential scanning calorimetry (TMDSC) measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time using fast scanning calorimetry employing both fast heating and cooling rates. This is complemented with scattering experiments that show how the size of the alkyl chain-rich domains increases with the side chain length. Alongside these results, a significant conductivity contribution was observed for all poly(tricyclononenes) with −Si(OR)3 side groups, which is interpreted in terms of a percolation model. T2 - DPG Online Spring Conference 2021 CY - Online meeting DA - 22.03.2021 KW - Dynamics KW - Glass transition KW - Conductivity PY - 2021 AN - OPUS4-52335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Li, Wei T1 - Crack propagation in filled and unfilled polymers: Separation of surface energy and irreversible deformation energy N2 - Fiber-reinforced-polymers (FRPs) are in current research focus in the lightweight construction industry, because of their extraordinary characteristics (stiffness and strength-to-density relation). The structure of polymer matrix and the interaction with reinforcement are crucial for optimization of the mechanical and thermal properties of FRPs. Due to the macromolecular chain structure, the mechanical properties of a polymer strongly vary with temperature: Below the glass transition, the chain segments of a polymer are “frozen”. Regarding fracture, the total changed energy during fracture if only dissipates for the generation of the new surfaces. However, in the region of the glass transition, the polymer chain segments start to get “unfrozen”, and the energy is not only required for generating new surfaces, but also for irreversibly deformation. This irreversible deformation is affected by the global temperature and the local temperature near the crack tip, which is affected by the local strain rate and crack propagation velocity. Hence, in this research project, the irreversible deformation of neat and reinforced polymers will be controlled by changing the global temperature as well as the local temperature. With using different fracture experiments, the amount of energy required for creating new surfaces and for the irreversible deformation will be separated. The fracture tests include the conventional tensile test, the macroscopic peel test and the single fiber peel – off test. T2 - PhD Day 2018 of BAM CY - Berlin, Germany DA - 31.05.2018 KW - Crack Propagation KW - Polymer PY - 2018 AN - OPUS4-48471 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Werner, Tiago T1 - Comparison of the fatigue behavior of wrought and additively manufactured AISI 316L N2 - Additively Manufactured (AM) parts are still far from being used in safety-relevant applications, mainly due to a lack of understanding of the feedstock-process-propertiesperformance relationship. This work aims at providing a characterization of the fatigue behavior of the additively manufactured AISI 316L austenitic stainless steel and a direct comparison with the fatigue performance of the wrought steel. A set of specimens has been produced by laser powder bed fusion (L-PBF) and a second set of specimens has been machined out of hot-rolled plates. The L-PBF material shows a higher fatigue limit and better finite life performance compared to the wrought material, accompanied by an extensive amount of cyclic softening. T2 - Fatigue Design 2021 CY - Online meeting DA - 17.11.2021 KW - Additive Manufacturing KW - AM KW - 316L KW - Fatigue KW - High Cycle Fatigue KW - Low Cycle Fatigue PY - 2021 AN - OPUS4-53780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cakir, Cafer Tufan T1 - Unravelling the depths of complex alloys with grazing exit XANES N2 - High entropy alloys (HEAs) are considered as a new class of alloys containing at least 5 elements with concentrations between 5 and 35 atomic percent. There has been a growing interest in HEAs in the material research field in recent years. Due to their adjustable composition, which enables the modifications of mechanical properties (such as hardness, strength and ductility etc) and their stability at high temperatures, HEAs have been the focus of various studies. Especially the corrosion behavior of HEAs has been a wide research interest. Since the grazing exit X-ray fluorescence (GEXRF) offers a non-destructive way to collect notable information regarding the high temperature oxidation, we consider it as a useful method to investigate how HEAs behave in corrosive environments. The main idea of grazing geometry is to enhance the fluorescence signal of the surface. This enables highly sensitive surface analyses of thin protective film on surface in sub-micrometer scale. Position-sensitive area detectors provide information regarding the signal emitted from the sample as a function of emission angle and thus allow depth-sensitive analysis. Furthermore, the data collected from samples of an incidence energy which lays within a specific energy range provides XANES data to determine oxidation states. Moreover, since GEXRF profiles can also be simulated through physical models (Urbach 1999), they enable us to determine the layer thickness of a given sample in a non-destructive way. In this contribution, we present the preliminary results of a conceptual study regarding layer properties of CrCoNi medium entropy alloy. The successful implementation of such methodological concept will pave the way for the investigation of more complex alloys with multiple layers, which is planned for the later phases of the project. T2 - Denver X-Ray Conference DXC 2021 CY - Online meeting DA - 02.08.2021 KW - GEXRF KW - High entropy alloys KW - XANES KW - Grazing exit KW - XAS PY - 2021 AN - OPUS4-54027 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Feiler, Torvid T1 - Mechanically plastic molecular crystals for shapeable optic waveguides N2 - Molecular crystalline materials are usually brittle and are prone to breaking when mechanically stressed. This fragility greatly limits they application in next the generation of adaptable, functional materials. The recent discovery of mechanical compliancy in molecular crystals has solved this problem.1 Based on the nature of the deformation, molecular crystals can be divided into being plastically (irreversibly) or elastically (reversibly) bendable. The plastic deformation is generally associated with anisotropic molecular arrangements and the existence of low energy slip planes which allow a permanent motion within the lattice. Here we report 4-bromo-6-[(6-chloropyridin-2-ylimino)methyl]phenol (CPMBP) as a promising candidate for future waveguide technologies.2 CPMBP has been found to have two different polymorphs with distinct optical and mechanical properties. The brittle crystals of Form I exhibits very weak emission at 605 nm (λex = 425 nm; photoluminescence quantum yield Φ = 0.4 %). In contrast, Form II has a large plastic regime together with a bright emission at 585 nm (λex = 425 nm; Φ = 8.7 %). Taking advantage of the favorable mechanical flexibility and optical properties, Form II was used as a shapeable optical waveguide. By changing the wavelength of the light source, active or passive waveguiding can be realized. CPMBP could thus be used as a flexible wavelength filter. T2 - 30. Jahrestagung der Deutschen Gesellschaft für Kristallographie CY - Online meeting DA - 14.3.2022 KW - Flexible crystals KW - Polymorphism KW - Waveguide PY - 2022 AN - OPUS4-54514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karafiludis, Stephanos T1 - Trash to treasure: recovery of transition metal phosphates for (electro-)catalytical applications N2 - Wastewaters containing high concentrations of NH4+, PO43- and transition metals are environmentally harmful and toxic pollutants. At the same time phosphorous and transition metals constitute valuable resources. Here, we report the synthesis routes for Co- and Ni-struvites (NH4MPO4∙6H2O, M = Ni2+, Co2+) out of aqueous solutions resembling synthetic/industrial waste water compositions, and allowing for P, ammonia and metal co-precipitation. Furthermore, the as-obtained struvites were further up-cycled. When heated, these transition metal phosphates (TMPs) demonstrate significant changes in the degree of crystallinity/coordination environment involving a high amount of amorphous phases and importantly develop mesoporosity (Figure 1). In this regard, amorphous and mesoporous TMPs are known to be highly promising (electro-)catalysts. Amorphous phases do not represent a simple “disordered” crystal but more a complex system with a broad range of compositions and physicochemical properties, which remain mostly unknown. Consequently, we investigated the recrystallization and amorphization process during thermal treatment and a resolved the complex amorphous/crystalline structures (Figure 2). As a proof-of-principle for their applicational use, the as-obtained TMPs demonstrate significant proton conductivity properties similar to apatite-like structures from room to high temperatures (>800°C). Hence, we have developed a promising recycling route in which environmental harmful contaminants like PO43-, NH4+ and 3d metals would be extracted out of waste waters in the form of precursor raw materials. These raw materials can be then further up-cycled through a simple thermal treatment for their specific application in electrocatalysis. T2 - Goldschmidt Conference 2022 CY - Hawai'i, USA DA - 10.07.2022 KW - Mesoporosity KW - Amorphous phases KW - Transition metals KW - Struvite KW - Phosphates PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552852 UR - https://conf.goldschmidt.info/goldschmidt/2022/meetingapp.cgi/Paper/9501 AN - OPUS4-55285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lohrer, Christian T1 - Fachbereich 2.5 Konformitätsbewertung Explosivstoffe/Pyrotechnik N2 - Vorstellung der Kernaufgaben Konformitätsbewertung Explosivstoffe und pyrotechnische Gegenstände und Hauptaktiviäten in diesem Sektor T2 - 42. Informationstagung Sprengtechnik CY - Siegen, Germany DA - 15.10.2021 KW - Explosivstoffe KW - Pyrotechnik KW - Normung KW - Konformitötsbewertung KW - Politikberatung PY - 2021 AN - OPUS4-54396 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Valet, Svenja T1 - Determination of the corrosion product layer resistance on zinc samples by using gel electrolytes N2 - Crash barriers, railings, lamp posts, waste glass containers - these are just a few of the many examples of galvanized surfaces. They withstand wind and weather for decades, which is possible thanks to a protective layer made of corrosion products. When designing the atmospheric durability of galvanized components, a linear corrosion loss is assumed. In the past 30 years, however, the surrounding atmosphere has changed a lot. Due to the restriction of sulfur exhaust air, acid rain completely disappeared in Europe and Germany, which has a direct influence on the type and protective effect of the corrosion products. Under the influence of current atmospheric conditions, zinc layers are significantly more resistant and no longer show any linear corrosion loss. The established test methods cannot correctly map this change in neither short-term nor long-term tests and thus provide incorrect results. In order to solve this problem, a new measurement method was developed at BAM that can assess the protective effect of the formed surface layers in a minimally invasive manner without damaging the sample and in short test times. For this new method, gel electrolytes are used and the so-called corrosion product layer resistance RL, which is made up of various surface resistances, is measured electrochemically. As a single measurement, the surface layer resistance can provide information about the existing corrosion protection, while time-dependent measurements assess the stability of the layer. Thus, it is possible again to evaluate the corrosion protection layer. Furthermore, this method can also be used for field measurements on real components. T2 - EUROCORR 2022 CY - Berlin, Germany DA - 28.08.2022 KW - Corrosion KW - Corrosion Testing KW - Gel electrolytes KW - Zinc and galvanized samples KW - Corrosion product layer PY - 2022 AN - OPUS4-55688 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönauer-Kamin, Daniela T1 - Powder-Aerosol deposited (PAD) calcium manganate as n-type thermoelectric material N2 - Currently, calcium manganate CaMnO3 and calcium cobaltite Ca3Co4O9 are being investigated as n-type resp. p-type semiconducting materials as oxidation- and temperature-resistant thermoelectric materials for oxide multilayer thermoelectric generators (TEGs). In order to manufacture multilayer TEGs, pressure-assisted sintering processes at high temperatures are necessary to achieve optimal thermoelectric material properties. To realize TEGs in planar film technology, another method to obtain dense ceramic layers directly from the synthesized starting powders without a subsequent high temperature step is emerging recently: the powder aerosol deposition (PAD) method. In the present work, it is investigated whether PAD is suitable to produce dense ceramic films from Sm-doped CaMnO3 and Ca3Co4O9 powders. The resulting thermoelectric properties are characterized as a function of temperature. CaMnO3 powder could successfully be processed by PAD with resulting layer thicknesses of 5- 6 µm without any high-temperature sintering steps of the films. The electrical conductivity and the Seebeck coefficient of the films were determined in-plane from room temperature to 600 °C in air. The results show a Seebeck coefficient of around -200 µV/K, which is comparable to results of pressed and sintered bars. At 400 °C, the electrical conductivity corresponds to the conductivity of the bar. At higher temperatures the conductivity is better than with the reference. Below 400°C, the electrical conductivity is somewhat lower than that of the reference sample, a mild thermal treatment of the PAD layer improves it. It is expected that the thermal conductivity of the PAD film will be lower compared to the bars due to the nano-crystalline film morphology. This should result in a significantly increased ZT value for the PAD layers and a higher efficiency of the TEG. The work shows that both CaMnO3 and Ca3Co4O9 can be successfully processed by PAD, and the PAD films show comparable thermoelectric properties. T2 - 18th European Conference on Thermoelectrics CY - Barcelona, Spanien DA - 14.09.2022 KW - Film depositition KW - Calcium cobaltite PY - 2022 AN - OPUS4-55771 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lohrer, Christian T1 - Fachbereich 2.5 Konformitätsbewertung Explosivstoffe/Pyrotechnik N2 - Vorstellung der aktuellen Aufgaben und Tätigkeiten des FB 2.5 Konformitätsbewertung Explosivstoffe/Pyrotechnik T2 - 43. Informationstagung Sprengtechnik CY - Siegen, Germany DA - 22.04.2022 KW - Benannte Stelle KW - Konformitätsbewertung KW - Normung KW - FE KW - Beratung Behörden/Ministerien PY - 2022 AN - OPUS4-54688 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lohrer, Christian T1 - Forschungsschwerpunkte im Fachbereich 2.5 Konformitätsbewertung Explosivstoffe/Pyrotechnik N2 - Vorstellung der aktuellen Forschungsthemen mit Bezug zu Explosivstoffen und pyrotechnischen Gegenstände T2 - 43. Informationstagung Sprengtechnik CY - Siegen, Germany DA - 22.04.2022 KW - Alterung von Pyrotechnik KW - Sprengplattieren KW - Fallhammer KW - Zünder PY - 2022 AN - OPUS4-54689 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ertural, Christina T1 - Automation of machine learning driven interatomic potential generation for predicting vibrational properties N2 - Investigating the phononic properties is beneficial for predicting low thermal conductivity thermoelectric materials.1–3 Employing density functional theory4 takes many calculation steps and consumes a lot of computational resources.5,6 Using machine learning driven interatomic potentials (MLIP, e.g., Gaussian approximation potential,8 GAP) opens up a faster route to phonons7 but in most cases, the potentials are specifically tailored for a certain compound. In this work, we automate the generation of such MLIPs in a Python code-based workflow, based on the automation tools atomate29 and pymatgen10 which combines the automatic DFT computations with the automated fitting of GAPs. Automation enables easier testing, benchmarking and validation.11 We aim to provide the workflow-generated potentials for storage in databases. T2 - 16th International conference on materials chemistry (MC16) CY - Dublin, Ireland DA - 03.07.2023 KW - Interatomic potentials KW - Machine learning KW - Phonons KW - Thermoelectrics PY - 2023 AN - OPUS4-57932 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bustamante, Joana A1 - Naik, Aakash A1 - Ertural, Christina A1 - Ueltzen, Katharina A1 - George, Janine T1 - Thermodynamic and Thermoelectric Properties of the Canfieldite, (Ag8SnS6 ), in the Quasi-Harmonic Approximation N2 - Argyrodite-type materials have lately sparked a lot of research interest due to their thermoelectric properties.One promising candidate is canfieldite (Ag8SnS6), which has a Pna21 orthorhombic crystal structure at room temperature (RT). Recently, a new low-temperature (LT) phase transition of canfieldite at 120K has been found. Here, we investigate structural, vibrational and thermodynamic properties of Ag8SnS6 at room- and low-temperature employing density functional theory (DFT) and lattice dynamics computations. Thermal properties calculations were based on the quasi-harmonic approximation (QHA) as implemented in phonopy. We achieve good agreement with experiments. Thermal properties such as the constant-pressure heat capacity (Cp) and thermal conductivity are very close to experimental measurements. Furthermore, we compared RT and LT Ag8SnS6 Grüneisen parameters with argyrodites analogues, Ag8XS6 (X = Sn, Si, Ge), to arrive at an improved T2 - 16th International conference on materials chemistry (MC16) CY - Dublin, Ireland DA - 03.07.2023 KW - Thermoelectric materials KW - DFT KW - QHA KW - Grüneisen parameter PY - 2023 AN - OPUS4-57887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Musl, O. T1 - Mapping the Hydrophobic Composition of Lignosulfonates with 2D HIC-SEC aq. Liquid Chromatography N2 - 2D-LC provides in-depth information on the complex composition of lignosulfonates – information hitherto inaccessible by state-of-the-art lignin analytics. Analysis of 12 industrial lignosulfonates revealed considerable differences in their composition and functional dispersity - properties that are crucial for lignosulfonate usage T2 - Sustainable Materials Research Summit 2022, S.M.A.R.T CY - Vancouver, Canada DA - 07.08.2022 KW - Lignosulfonate KW - Lignin KW - Amphiphilicity KW - Hydrophobic interaction KW - Chromatography (HIC) KW - Size-exclusion chromatography (SEC) KW - Functionality type distribution KW - Two-dimensional liquid chromatography (2D-LC) KW - Molar mass distribution PY - 2022 AN - OPUS4-55510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karafiludis, Stephanos A1 - Stawski, Tomasz T1 - Crystallization study of transition metal phosphates: Characterization of a non-classical crystallization pathway N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.), which contain high concentrations of NH4+, PO43- and transition metals, are environmentally harmful due to their toxic pollutants. At the same time, phosphorus and selective transition metals such as Cobalt could be potentially depleted as a critical raw material due to the high demand and rapidly declining natural ore deposits. Therefore, due to simultaneous scarcity and abundance, the phosphorus and 3d metal recovery from agricultural, industrial, mining, or urban wastewaters have been an important factor in sustaining our global consumption and preservation of the natural environment. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we investigate the crystallization of transition metal phosphate (TMP) compounds (NH4MPO4∙6H2O, M3(PO4)2∙8H2O with M = Ni2+, Co2+, NixCo1-x2+ M-struvite and M-phosphate octahydrate) out of aqueous solutions, which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters has high potential as a P- and 3d metal recovery route. For this purpose, a detailed understanding of the crystallization process beginning from combination of solved ions and ending in a final crystalline product is required. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMPs could be controlled. Detailed investigations of the precipitation process in time using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases during the crystallization process. Over time, their complex amorphous framework changes significantly resulting simultaneously in an agglomeration and densification of the compound. After extended reaction times these colloidal nanophases condensed to a final crystal. However, the reaction kinetics of the formation of a final crystalline product and the lifetime of these intermediate phases vary significantly depending on the metal cation involved in the precipitation process. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The mixed NixCo1-x system shows a significantly different crystallization behavior and reaction kinetics of the precipitation compared to the pure endmembers. The observed various degree of stability could be linked to the octahedral metal coordination environment in these compounds. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications. T2 - HZB Usermeeting 2023 CY - Berlin, Germany DA - 22.06.2023 KW - Struvite KW - Transition metal KW - Phosphates KW - Crystallization KW - Amorphous phases PY - 2023 AN - OPUS4-57775 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karafiludis, Stephanos T1 - Crystallization study of transition metal phosphates: A novel example for non-classical crystallization theory N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.) which contain high concentrations of NH4+, PO43- and transition metals are environmentally harmful and toxic pollutants . Typically, separate pathways have been considered to extract hazardous and transition metals or phosphate as critical raw materials, independently from each other. Here, we report the synthesis routes for transition metal phosphate (TMP) compounds (M3(PO4)2∙8H2O, NH4MPO4∙6H2O, M = Ni2+, Co2+, M-struvite and M-phosphate octahydrate), which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters could be a promising P-recovery route. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMP could be controlled. Detailed investigations of the precipitation process using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases which subsequently aggregate and condense to final crystals after extended reaction times. However, the reaction kinetics of the formation of a final crystalline product vary significantly depending on the metal cation(s) involved in the precipitation process. The occurring amorphous nanophases seem to majorly influence the outcome of crystallization. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The observed various degree of stability could be linked to the octahedral metal coordination environment. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications 4. T2 - GeoMin Köln Konferenz 2022 CY - Cologne, Germany DA - 11.09.2022 KW - Non-classical crystallization theory KW - Amorphous phases KW - Transition metal KW - Phosphates KW - Diffraction PY - 2022 UR - https://www.geominkoeln2022.de/programme.html AN - OPUS4-55874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Amariamir, Sasan A1 - Benner, Philipp A1 - George, Janine T1 - Prediction of materials synthesizability N2 - In the pursuit of discovering materials with desirable properties, extending the available material libraries is crucial. High-throughput simulations have become an integral part in designing new materials in the past decades. However, there is no straightforward way of distinguishing synthesizable materials from all the proposed candidates. This project focuses on employing AI-driven methods to estimate synthesizability of materials. Up to now, material scientists and engineers have relied on domain knowledge as well as empirical heuristics to guess the stability and synthesizability of molecules and crystals. The famous Pauling rules of crystal stability are an example of such heuristics. However, after the accelerating material discovery in all the years since Pauling, these rules now fail to account for the stability of most known crystals. A new predictive set of heuristics for crystal stability/synthesizability is unlikely to be uncovered by human perception, given the magnitude and dimensionality of crystallographic data. Hence, a data-driven approach should be proposed to find a predictive model or set of heuristics which differentiate synthesizable crystal structures from the rest. The main challenge of this research problem is the lack of a negative set for classification. Here, there are two classes of data: the positive class which contains synthesizable materials and the negative class which contains materials which are not synthesizable. While the data from the positive class is simply the data of crystals which have been experimentally synthesized, we do not have access to data points which are certainly unsynthesizable. Strictly speaking, if an attempt of synthesizing a crystal fails, it does not necessarily follow that the crystal is not synthesizable. Also, there is no database available which contains the intended crystal structures of unsuccessful synthesis attempts. This project proposes a semi-supervised learning scheme to predict crystal synthesizability. The ML model is trained on experimental and theoretical crystal data. The initial featurization focuses on local environments which is inspired by the Pauling Rules. The experimental data points are downloaded through the Pymatgen API from the Materials Project database which contains relaxed structures recorded in Inorganic Crystal Structure Database – ICSD. The theoretical data is queried from select databases accessible through the Optimade project’s API. T2 - MSE Congress 2022 CY - Darmstadt, Germany DA - 27.09.2022 KW - Synthesizability KW - PU Learning KW - Cheminformatics PY - 2022 AN - OPUS4-56731 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Costard, René T1 - “Kalte Pyrotechnik” – heißes Thema oder heiße Luft? N2 - Das Poster zeigt Ergebnisse von Messungen der Verbrennungstemperaturen und Aerosolemissionen von "kalter Pyrotechnik" und einem Seenotrettungsmittel im Vergleich. T2 - 44. Informationstagung Sprengtechnik CY - Siegen, Germany DA - 14.04.2023 KW - Pyrotechnik KW - Missbräuchliche Verwendung in Stadien KW - Aerosole PY - 2023 AN - OPUS4-57311 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dengel, Jörg T1 - Untersuchung des Alterungsverhaltens von pyrotechnischen Seenotrettungsmitteln N2 - Das Poster zeigt Ergnisse der Untersuchung der Alterungsprozesse von pyrotechnischen Seenotrettungsmitteln (kleine schwimmfähige Rauchsignale und Seenotfackeln). Dabei erfolgte die Bewertung der thermischen und chemischen Stabilität sowie der Funktionssicherheit. Die beschleunigte Alterung (EN 16263:2015) und andere Methoden wurden mit natürlich gealterten Gegenständen verglichen T2 - 44. Informationstagung Sprengtechnik CY - Siegen, Germany DA - 14.04.2023 KW - Alterung von Pyrotechnik KW - Seenotrettungsmittel PY - 2023 AN - OPUS4-57312 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hertwig, Andreas T1 - Determining thermal transitions in thin polymer layers by means of spectroscopic ellipsometry N2 - Thin polymer layers have enormous technical significance as polymer coatings on materials are very cost-effective for tailoring properties of surfaces. Apart from technical aspects in their use, thin polymer layers can be used to determine dimensional aspects in properties of material, such as confinement effects. In this work, we investigated several different polymer layer materials and determined their glass transition region by means of temperature-dependent spectroscopic ellipsometry. We have optimised our fitting procedure of the ellipsometric data produced in temperature ramp experiments. By this, we could measure the dependence of Tg on the layer thickness in a wide variety of thickness values, proving the existence of confinement effects in the investigated systems. We compare numerical methods for determining the location of the glass transition and discuss the possibilities of different analysis methods when determining thermal transitions. We also discuss the simultaneous existence of these transitions and annealing effects and the implications on the accuracy of the determined data. T2 - 12th Workshop Ellipsometry 2023 CY - Prague, Czech Republic DA - 18.09.2023 KW - Thin Films KW - Polymers KW - Ellipsometry KW - Themal Transitions PY - 2023 AN - OPUS4-58413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lengas, Nikolaos A1 - Müller, Karsten A1 - Schlick-Hasper, Eva A1 - Neitsch, Marcel A1 - Johann, Sergej A1 - Zehn, M. W. T1 - FEA of the mechanical response of installed impact target foundations in drop tests of dangerous goods packagings N2 - Packagings for the transport of dangerous goods need to meet special requirements to get an approval. This includes free fall drop testing onto an essentially unyielding surface as a means to assess a package’s resistance to mechanical damage. A main requirement for drop tests is that the impact target’s mass shall be at least 50 times that of the heaviest package to be tested. Nevertheless, many manufacturers do not possess foundation structures with the required mass ratio. Previous evidence highlights that the mass ratio is not a decisive criterion on its own. Parameters such as the impact target foundation’s connection and the impulse experienced by the impacting object are essential as well. However, these factors are not easily verifiable since experimental measurements are not possible at most facilities. The objective of this work is to provide a detailed analysis on the interaction between impact target foundation and subgrade in dynamic impact testing using validated finite-element (FE) models. This research is highly beneficial for industrial application since it allows manufacturers to make informed predictions about the mechanical response of installed impact target foundations. T2 - FEMS EUROMAT 2023 CY - Frankfurt a. M., Germany DA - 03.09.2012 KW - Dangerous goods packagings KW - Drop test KW - Foundation KW - Structural dynamics PY - 2023 AN - OPUS4-58213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayerlein, Bernd T1 - PMDco - Platform MaterialDigital Core Ontology N2 - The PMD Core Ontology (PMDco) is a comprehensive set of building blocks produced via consensus building. The ontological building blocks provide a framework representing knowledge about fundamental concepts used in Materials Science and Engineering (MSE) today. The PMDco is a mid-level ontology that establishes connections between narrower MSE application ontologies and domain neutral concepts used in already established broader (top-level) ontologies. The primary goal of the PMDco design is to enable interoperability between various other MSE-related ontologies and other common ontologies. PMDco’s class structure is both comprehensive and extensible, rendering it an efficient tool to structure MSE knowledge. The PMDco serves as a semantic middle-layer unifying common MSE concepts via semantic mapping to other semantic representations using well-known key terms used in the MSE domain. The PMDco enables straight-forward documentation and tracking of science data generation and in consequence enables high-quality FAIR data that allows for precise reproducibility of scientific experiments. The design of PMDco is based on the W3C Provenance Ontology (PROV-O), which provides a standard framework for capturing the production, derivation, and attribution of resources. Via this foundation, the PMDco enables the integration of data from various data origins and the representation of complex workflows. In summary, the PMDco is a valuable advancement for researchers and practitioners in MSE domains. It provides a common MSE vocabulary to represent and share knowledge, allowing for efficient collaboration and promoting interoperability between diverse domains. Its design allows for the systematic integration of data and metadata, enabling seamless tracing of science data. Overall, the PMDco is a crucial step towards a unified and comprehensive understanding of the MSE domain in general. T2 - FEMS EUROMAT 2023 CY - Frankfurt a. M., Germany DA - 03.09.2023 KW - Knowledge Representation KW - Ontology KW - Semantic Interoperability KW - FAIR KW - Automation PY - 2023 AN - OPUS4-58197 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Seeber, Henrik T1 - Experimenteller Ansatz zur Untersuchung der primären Explosionswirkung N2 - Explosionsverletzungen gehören zu den häufigsten Verletzungen bei militärischen Einsätzen. Während die Auswirkungen von Splittern, die als sekundäre Explosionsverletzungen eingestuft werden, durch die modernen ballistischen Körperschutzsysteme der Polizei und des Militärs minimiert werden konnten, stellen die Auswirkungen der Stoßwellenausbreitung im Körper als Teil des primären Explosionstraumas nach wie vor eine ernsthafte Bedrohung dar. Zusätzlich zu einzelnen einsatzbedingten Lastfällen liegt ein wissenschaftlicher Fokus auf besonders exponiertem Personal, z.B. aus den Einsatzbereichen „Taktische Zugangstechnik“, „Präzisionsschützenwesen“ oder Steilfeuerwaffen (Mörser). Repetitive mild traumatic brain injury (mTBI) können gesundheitliche Langzeitschädigungen wie und chronic traumatic encephalopathy (CTE) erzeugen. Um einen Beitrag zur Erforschung der primären Explosionswirkungen zu leisten, hat die Bundeswehr in Zusammenarbeit mit dem Bundeswehrkrankenhaus Berlin und der Bundesanstalt für Materialforschung und -prüfung (BAM) ein interdisziplinäres wehrmedizinisches Sonderforschungsvorhaben eingerichtet. Ziel der geplanten Untersuchung ist die Entwicklung einer multidisziplinären Methode zur Analyse des Stoßwellenverhaltens in verschiedenen generischen Gewebesimulanzien, sowie Schutzmaterialien unter möglichst realitätsnahen und reproduzierbaren Bedingungen. Für die Erzeugung reproduzierbarer Stoßwellen wurde ein Autoklav (Druckbehälter) entwickelt, mit dem durch die detonative Umsetzung eines Acetylen-Sauerstoff-Gemisches gut reproduzierbare Druckwellen unter Freifeldbedingungen erzeugt werden können. Vorteile dieser Methode sind unter anderem die kurzen Rüstzeiten zwischen Versuchsdurchgängen, die Minimierung störender Einflüsse im Vergleich zu Stoßwellenrohren und die geringeren Sicherheitsanforderungen im Vergleich zur Anwendung von konventionellen Sprengstoffen. Das generische Torso-Modell besteht in seiner einfachsten Form aus einem mit Druck- und Beschleunigungssensoren instrumentierten Gelatineblock, welcher eine Simulanz für organisches Gewebe darstellt. Zur Untersuchung des Stoßwellenverhaltens wurden verschiedene Medien, wie Hohlkörper, Festkörper und Gewebesimulanzien differenter Dichte in das generische Torso-Modell eingebracht. Einen besonderer Untersuchungsschwerpunkt bildeten die Grenzbereiche zwischen den unterschiedlichen Medien. Des Weiteren wurde analysiert, wie sich verschiedene Schutzmaterialien auf das Stoßwellenverhalten auswirken und mit welchen veränderten Eigenschaften die Stoßwelle anschließend in die Gewebesimulanz einkoppelt. T2 - Angewandte Forschung für Verteidigung und Sicherheit in Deutschland CY - Bonn, Germany DA - 19.03.2024 KW - Primäre Explosionswirkug KW - Blast injury KW - Pressure wave KW - Druckwelle PY - 2024 AN - OPUS4-59474 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cook, Jake Thomas T1 - Assessment of concrete bioreceptivity in algal biofilm green façade systems N2 - Algal biofilm façades are an alternative to traditional green façades which can help to improve biodiversity and air quality within cities. They present a low maintenance approach in which subaerial algae are grown directly on concrete substrates. The intrinsic bioreceptivity of the substrate is a critical factor in successful facade colonisation. Existing research has identified several environmental and material properties which influence concrete bioreceptivity, however a consensus has yet to be made on which properties are most influential and how the interaction between properties may promote algal biofilm growth under specific conditions. T2 - International Conference on Bio-Based Building Materials CY - Vienna, Austria DA - 21.06.2023 KW - Concrete KW - Façade KW - Bio-receptive KW - Extracellular polymeric substances KW - Fractional factorial PY - 2023 UR - https://www.rilem.net/agenda/5th-international-conference-on-bio-based-building-materials-1501 AN - OPUS4-58976 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus T1 - PMDco: Achieving High-Quality & Reliable FAIR Data N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific. In this presentation, an approach how to maintain a comprehensive and intuitive MSE-centric terminology composing a mid-level ontology–the PMD core ontology (PMDco)–via MSE community-based curation procedures is shown. The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications. T2 - Kupfer-Symposium CY - Jena, Germany DA - 29.11.2023 KW - Ontology KW - Semantic Web Technologies KW - Plattform MaterialDigital KW - PMDco PY - 2023 AN - OPUS4-59031 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Casali, Lucia T1 - Use of the solvent-free mechanochemical method for a sustainable preparation of pharmaceuticals N2 - With the growing interest in environmental issues on the part of governments and institutions, pharmaceutical industries are asked to reduce their environmental footprint. Given the major impact related to the use of solvents, the development of methodologies less solvent demanding is nowadays even more urgent. In light of that, mechanochemistry would be a suitable solvent-free technology since it promotes the activation of the chemical reactions between (generally) solid materials via inputs of mechanical energy. Since such reactions may occur outside the kinetic and thermodynamic rules of conventional solution chemistry, the main limit of mechanochemistry is the poor mechanistic understanding of the solid-state transformations involved, which is still hindering a widespread use of the method, as well a scale-up to the industrial level. However, the development of methods for real-time monitoring of the mechanochemical reactions enables obtaining (in)accessible information on reaction intermediates, new products, or reaction time, thus getting closer to a better understanding of the mechanistic behaviour. With the rules of this chemistry becoming increasingly clear, the new reaction pathways of mechanochemistry wouldn’t represent a limit anymore, but an asset, that may lead to lot of opportunities for the pharmaceutical industry. T2 - Post Doc Day Berlin CY - Berlin, Germany DA - 02.11.2023 KW - Mechanochemistry KW - Sustainability KW - Pharmaceuticals PY - 2023 AN - OPUS4-59010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waske, Anja A1 - Fähler, Sebastian T1 - Thermomagnetic generators with magnetocaloric materials for harvesting low grade waste heat N2 - To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. This switches a magnetic flux and, according to Faraday’s law, induces a voltage. Here we give an overview on our research, covering both materials and systems. We demonstrate that guiding the magnetic flux with an appropriate topology of the magnetic circuit improves the performance of thermomagnetic generators by orders of magnitude. Through a combination of experiments and simulations, we show that a pretzel-like topology results in a sign reversal of the magnetic flux. This avoids the drawbacks of previous designs, namely, magnetic stray fields, hysteresis and complex geometries of the thermomagnetic material. Though magnetocaloric materials had been the first choice also for thermomagnetic generators, they require some different properties, which we illustrate with Ashby plots for materials selection. Experimentally we compare La-Fe-Co-Si and Gd plates in the same thermomagnetic generator. Furthermore, we discuss corrosion and deterioration under cyclic use is a severe problem occurring during operation. To amend this, composite plates using polymer as a matrix have been suggested previously. T2 - Dresden Days of Magnetocalorics CY - Dresden, Germany DA - 13.11.2023 KW - Thermomagnetic material KW - Waste heat recovery KW - Generator PY - 2023 AN - OPUS4-58865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bhattacharya, Biswajit A1 - Akhmetova, Irina A1 - Rautenberg, Max A1 - Emmerling, Franziska T1 - Mechanochemical synthesis of phosphonate-based proton conducting metal organic frameworks and hydrogen-bonded metal phosphonates N2 - Proton exchange membrane fuel cells (PEMFCs) are one of the most promising alternative green energy technologies that deliver high energy density without CO2 emissions. The proton conductivity of proton exchange membranes (PEM) contributes to the overall efficiency of a PEMFC. Materials being used as PEMs must exhibit high proton conductivity at the working conditions of the targeted PEMFC. To date, Nafion and Nafion-like polymers with acidic functionality are widely used as membrane materials due to their high proton conductivity in the range of 10-1 to 10-2 Scm-1 at higher relative humidity. However, these materials suffer from high costs, hazardous production process, and poor performance at high temperatures, limiting their versatility. In this context, crystalline porous materials are recognized as promising proton conductors for the proton exchange membrane (PEM) in fuel cell technology, owing to their tunable framework structure. However, it is still challenging bulk synthesis for real-world applications of these materials. Herein, we present mechanochemical gram-scale synthesis of series of mixed ligand metal organic frameworks (MOFs) and metal hydrogen‐bonded organic frameworks (MHOFs) using phenylene diphosphonic acid and 1-hydroxyethylidene-1,1-diphosphonic acid with different bipyridyl type of ligands, respectively. In all cases, the existence of extensive hydrogen bonds with amphiprotic uncoordinated phosphonate hydroxyl and oxygen atoms, the frameworks exhibited high proton conductivity. The study demonstrates the potential of green mechanosynthesis for preparations of framework-based proton conducting materials in bulk scale for green energy generation. T2 - 4th International Conference on Phosphonate Chemistry, Science and Technology, ICOPHOS-4 CY - Crete, Greece DA - 02.10.2023 KW - Proton exchange membrane fuel cells KW - Metal organic frameworks KW - Proton conducting materials PY - 2023 AN - OPUS4-58837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus T1 - PMDco - Platform MaterialDigital Core Ontology: Achieving High-Quality & Reliable FAIR Data N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific. In this poster presentation, an approach how to maintain a comprehensive and intuitive MSE-centric terminology composing a mid-level ontology–the PMD core ontology (PMDco)–via MSE community-based curation procedures is shown. The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications. T2 - DVM Arbeitskreis Betriebsfestigkeit - Potenziale der Betriebsfestigkeit in Zeiten des technologischen und gesellschaftlichen Wandels CY - Munich, Germany DA - 11.10.2023 KW - Digitalization KW - Semantic Web Technologies KW - FAIR KW - Data Interoperability KW - PMD Core Ontology PY - 2023 AN - OPUS4-58602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heinekamp, Christian T1 - Dispersible SnO2 nanoparticles - a structural phenomenon N2 - Previous work in the Dunne Group targeted dispersibility of metal oxide nanoparticles, which had been synthesised via an aqueous sol-gel route. Dispersibility was attained by solvothermal surface modification of the particles with trifluoro acetic acid. Part of the studies were tin oxide particles, which is known for its predominant rutile phase. Despite dispersibility in acetone of the particles unexpected peak splitting of the first (110) reflection was observed. Intensive long-term reaction studies on the tin oxide particles exhibited a time dependent extend of the peak splitting observed in XRD character-isation. Extended characterisation using solid-state multinuclear MAS-NMR spectroscopy indicate size dependent structure change due to partial fluorination of the particles during the solvothermal treatment. T2 - RSC Twitter Poster Conference 2022 CY - Online meeting DA - 01.03.2022 KW - SnO2 KW - Nanoparticles PY - 2022 AN - OPUS4-57225 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heinekamp, Christian T1 - Structure analysis of dispersible SnO2 nanoparticlesStructure analysis of dispersible SnO2 nanoparticles N2 - Previous work in the Dunne Group targeted dispersibility of metal oxide nanoparticles, which had been synthesised via an aqueous sol-gel route. Dispersibility was attained by solvothermal surface modification of the particles with trifluoro acetic acid (TFA). Part of the studies were tin oxide particles, which is known for its predominant rutile phase. Besides the dispersibility in acetone of the particles, an unexpected peak splitting of the (110) reflection was observed, which could be an unknown phase of SnO2 . For crystal growth long-term reaction studies on the tin oxide particles were performed. Interestingly these studies exhibited a time dependent extend of the peak splitting observed in XRD characterisation. Further extended analysis using multinuclear solid-state MAS-NMR spectroscopy indicate a size dependent structure change due to partial fluorination of the particles during the solvothermal treatment. T2 - SALSA Make and Measure 2022 CY - Online meeting DA - 07.09.2022 KW - SnO2 KW - Nanoparticles PY - 2022 AN - OPUS4-57201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heinekamp, Christian T1 - Metal fluoride surfaces by protonation with surface immobilized HF N2 - Lewis-acidic zirconium or chromium fluoride surfaces on different aluminium oxide or fluoride substrates. T2 - CRC 1349 Symposium 2021 CY - Berlin, Germany DA - 25.11.2021 KW - HF KW - Heterogeneous catalysis PY - 2021 AN - OPUS4-57226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fink, Friedrich T1 - Mechanochemical valorisation of kraft-lignin N2 - As one of nature's largest carbon sources with an annual production of around 20 billion tonnes, lignin is the third most abundant biopolymer on the planet. It becomes available as technical lignin, which is produced as a by-product in the pulp and paper industry and in smaller quantities in second generation biofuel refineries. Current estimates suggest that less than 10% of all technical lignin is reused. The high polydispersity, complex heterogeneous structure and uncertain reactivity are the major limiting factors for further processing. The most common applications for various technical lignins without extensive modifications are for example: Surface active substances, additives in bitumen, cement and animal feed. One way to make lignin usable is to break the structure into oligomer units and thus reduce the polydispersity and average molar mass. In addition, it is advantageous to introduce new functionalities such as hydroxyl or carbonyl groups when splitting the high-molecular-weight (HMW) fractions, or to convert existing functionalities. In this study, a mechanochemical method is presented that can degrade and modify technical kraft lignin by means of sodium percarbonate (SPC). T2 - 10th Intern. Symp. on the Separation and Characterisation of Natural and Synthetic Macromolecules (SCM-10) CY - Amsterdam, Netherlands DA - 01.02.2023 KW - Technical Lignin KW - Mechanochemical oxidation PY - 2023 AN - OPUS4-57001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, M. A1 - Schlingmann, T. A1 - Schmidt, J. A1 - Bettge, Dirk A1 - Hilgenberg, Kai A1 - Binder, M. A1 - Klöden, B. T1 - A Round Robin Test To Investigate The Printing Quality Of PBF LB/M Processed AlSi10Mg N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail. T2 - World PM2022 CY - Lyon, France DA - 09.10.2022 KW - Additive manufacturing KW - AlSi10Mg KW - Laser powder bed fusion KW - Round robin KW - Reproducibility PY - 2022 AN - OPUS4-56303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Linberg, Kevin T1 - Polymorphism in molecular cocrystals controlled by variable temperature ball milling N2 - Mechanochemistry offers a unique opportunity to modify or synthesize new crystal forms. Although the method is very promising, little is known about the mechanochemical means to control the synthesis of a solid form. Using an polymorphic organic cocrystal system, we show here that mechanochemistry can be used to obtain a polymorph transformation under the apparently conventional (thermal) transition point. T2 - Bessy User Meeting 2022 CY - Online meeting DA - 08.12.2022 KW - Mechanochemistry KW - Polymorphism KW - TRIS PY - 2022 AN - OPUS4-56473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karafiludis, Stephanos T1 - How do transition metal phosphates crystallise? N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.), which contain high concentrations of NH4+, PO43- and transition metals, are environmentally harmful due to their toxic pollutants. At the same time, phosphorus and selective transition metals such as Cobalt could be potentially depleted as a critical raw material due to the high demand and rapidly declining natural ore deposits. Therefore, due to simultaneous scarcity and abundance, the phosphorus and 3d metal recovery from agricultural, industrial, mining, or urban wastewaters have been an important factor in sustaining our global consumption and preservation of the natural environment. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we investigate the crystallization of transition metal phosphate (TMP) compounds (NH4MPO4∙6H2O, M3(PO4)2∙8H2O with M = Ni2+, Co2+, NixCo1-x2+ M-struvite and M-phosphate octahydrate) out of aqueous solutions, which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters has high potential as a P- and 3d metal recovery route. For this purpose, a detailed understanding of the crystallization process beginning from combination of solved ions and ending in a final crystalline product is required. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMPs could be controlled. Detailed investigations of the precipitation process in time using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases during the crystallization process. Over time, their complex amorphous framework changes significantly resulting simultaneously in an agglomeration and densification of the compound. After extended reaction times these colloidal nanophases condensed to a final crystal. However, the reaction kinetics of the formation of a final crystalline product and the lifetime of these intermediate phases vary significantly depending on the metal cation involved in the precipitation process. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The mixed NixCo1-x system shows a significantly different crystallization behavior and reaction kinetics of the precipitation compared to the pure endmembers. The observed various degree of stability could be linked to the octahedral metal coordination environment in these compounds. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications. T2 - Granada Münster Discussion Meeting (GMDM) CY - Granada, Spain DA - 30.11.2022 KW - Struvite KW - Transition metal KW - Phosphates KW - Amorphous phases KW - Non-classical crystallization PY - 2022 AN - OPUS4-56478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karafiludis, Stephanos T1 - Crystallization study of transition metal phosphates: a new example for non-classical crystallization theory N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.), which contain high concentrations of NH4+, PO43- and transition metals, are environmentally harmful due to their toxic pollutants. At the same time, phosphorus and selective transition metals such as Cobalt could be potentially depleted as a critical raw material due to the high demand and rapidly declining natural ore deposits. Therefore, due to simultaneous scarcity and abundance, the phosphorus and 3d metal recovery from agricultural, industrial, mining, or urban wastewaters have been an important factor in sustaining our global consumption and preservation of the natural environment. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we report the synthesis routes for transition metal phosphate (TMP) compounds (M3(PO4)2∙8H2O, NH4MPO4∙6H2O, M = Ni2+, Co2+, NixCo1-x2+ M-struvite and M-phosphate octahydrate), which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters could be a promising P-recovery route. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMP could be controlled. Detailed investigations of the precipitation process using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases which subsequently aggregate and condense to final crystals after extended reaction times. However, the reaction kinetics of the formation of a final crystalline product vary significantly depending on the metal cation involved in the precipitation process. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The mixed NixCo1-x system shows a significantly different crystallization behavior and reaction kinetics of the precipitation compared to the pure endmembers. The observed various degree of stability could be linked to the octahedral metal coordination environment in these compounds. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications. T2 - Adlershofer Forschungsforum 2022 CY - Berlin, Gemany DA - 11.11.2022 KW - Transition metal KW - Phosphates KW - Non-classical crystallization KW - In-situ SAXS/WAXS KW - Cryo-TEM PY - 2022 AN - OPUS4-56479 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epperlein, Martin T1 - QI-Digital - Qualitätssicherung für die Additive Fertigung N2 - Für die konventionelle Fertigung hat sich das bestehende System der Qualitätsinfrastruktur (QI) bewährt. Die additive Fertigung vergrößert den gestalterischen Spielraum von möglichen Bauteilgeometrien und Prozessfehlern jedoch erheblich. Hier gerät die QI an ihre Grenzen, sodass die Fertigung und Zulassung sicherheits-relevanter Bauteile sehr zeit- und kostenintensive Versuche erfordern. Eine moderne digitale QI erlaubt eine effizientere Qualitätssicherung für additiv gefertigte Bauteile. Dies erfordert eine durchgängig digitale Abbildung des physischen Materialflusses. T2 - QI-Forum CY - Berlin, Germany DA - 11.10.2022 KW - Additive Fertigung KW - Qualitätssicherung KW - Digitalisierung PY - 2022 AN - OPUS4-56382 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Strauß, Lea T1 - Empirical Model for Fatigue Life Prediction N2 - Laser-based powder bed fusion (PBF-LB) is an advanced additive manufacturing technique renowned for its precision and capability to fabricate complex metal components. However, the high thermal gradients and rapid cooling rates intrinsic to this process introduce significant process-induced effects, such as inhomogeneities, surface roughness, anisotropy, and residual stress, all of which critically influence the fatigue behavior of the produced parts. This study investigates the fatigue performance of AlSi10Mg samples produced by PBF-LB, examining the impact of varying surface conditions, geometries, and residual stress levels. Fatigue life prediction models are formulated based on nominal stress amplitude, residual stress, notch factor, crackinitiating inhomogeneity, and surface roughness, with smooth samples serving as a baseline reference. The study presents two empirical models for predicting fatigue life and fatigue strength using S-N curves and the Kitagawa-Takahashi diagram with the El Haddad approach, derived from comprehensive experimental data, including finite element modelling, fatigue life measurements, surface roughness evaluations, and residual stress analysis. T2 - ICAM2024 CY - Atlanta, GA, USA DA - 28.10.2024 KW - AlSi10Mg KW - Kitagawa-Takahashi diagram KW - Equivalent stress KW - Fatigue life prediction KW - PBF-LB/M PY - 2024 AN - OPUS4-61538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina T1 - Supramolecular Polymerization Induced by Confined Structural Water in Small Crown Macrocycle N2 - Structural water, integral to biological systems, i.e., for protein stability and function, has rarely been explored in materials science. Supramolecular polymers, which assemble through non-covalent interactions, offer functionalities such as responsiveness and self-healing. Traditionally, in such systems water is considered as a solvent. Herein, a novel water-induced supramolecular polymer hydrogel is reported, formed by a single crown ether macrocycle with a selenoxide hydrogen bonding receptor and a hydrophobic selenium-substituted core. Structural water was confined in a nanosegregated three-dimensional architecture, maintaining water in a liquid-like state down to -80 °C. Unlike previous studies requiring multiple crown ether units for structural water formation, this single unit system effectively controls structural water and supramolecular polymerization. The presence of confined water was revealed through dielectric and Flash DSC experiments. The resulting hydrogel exhibits exceptional adhesion to hydrophilic surfaces, retaining strength at low temperatures. These findings demonstrate the significant role of a single macrocycle in governing water structure and functionality in supramolecular systems. An expansion of the understanding of water's role beyond a solvent has been achieved, showcasing its potential as a comonomer in material science, particularly in the development of responsive, adhesive supramolecular polymers and hydrogels. T2 - Polydays 2024 CY - Berlin, Germany DA - 30.09.2024 KW - Hydrogels KW - Structural water PY - 2024 AN - OPUS4-61658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Melzer, Michael T1 - The temperature DCC exposed N2 - The DAkkS-accredited calibration laboratory of the German Federal Institute for Materials Research and Testing (BAM) has established valid XML digital calibration certificates (DCCs) for calibrations of resistance thermometers within the scope of its accreditation. Hence, all necessary information according to ISO/IEC 17025 and the DKD-R 5-1 calibration rule is provided in a machine-readable and machine-interpretable form. Furthermore, we actively participate in the definition of general and community-specific good practice requirements for the DCC of temperature quantities as technical specifications, hosted by the German Calibration Service (DKD). In this contribution the entire XML source code of a DCC from a Pt 100 thermometer calibration will be exposed and discussed. The DCC was automatically generated using a self-implemented middleware that is compiling the metadata (i.e. customer-, order-, item- and method data) and combines it with the measured calibration data and influence conditions into a process- and lab-specific DCC template. Since it was issued as an accredited calibration certificate, the validated and authorized DCC is also equipped with the novel digital accreditation symbol to form an `eAttestation´. This advanced electronic seal with a qualified certificate was recently piloted with the German national accreditation body (DAkkS), and, after successful validation by the receiver, verifies the active accreditation status of the issuing body at the time of sealing (authorization). As it also provides all other functionalities of an electronic seal, (i.e. data integrity and authenticity), it can fully replace a digital signature on accredited DCCs. The presented temperature DCC architecture fully complies to the latest good practice definitions of the DKD and thus represents a level 4 DCC according to the utility model for machine interpretability of DCCs. This also includes basic and quantity-specific refType definitions that are linked to an online refType repository to harmonize these key semantic providing elements across other DCC-issuing laboratories. The paper and also its conference poster will not represent a general introduction and motivation for the DCC itself. It rather addresses more detailed aspects of good practice, especially for DCCs from temperature quantity calibrations and may stimulate in-depth discussions between DCC experts from the providing, utilizing and accrediting points of view. The work was performed within the national QI-Digital initiative of the German Federal Ministry for Economic Affairs and Climate Action. T2 - IMEKO 2024 XXIV World Congress CY - Hamburg, Germany DA - 26.08.2024 KW - Digital Calibration Certificate KW - E-Attestation KW - QI-Digital KW - Digital Metrology KW - Calibration PY - 2024 UR - https://www.imeko2024.org/home AN - OPUS4-61872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schob, Daniela T1 - Comparative Analysis FFF vs. cold rolled 316L Samples N2 - This study provides insights into the properties of 316L stainless steel produced by additive manufacturing using fused filament fabrication (FFF). One key finding is particularly noteworthy: in significant contrast to cold-rolled 316L, FFF316L develops a pronounced martensite phase after fabrication. The comprehensive comparative analysis shows that FFF316L not only retains the ferrite volume content, but that this is also significantly influenced by the build-up direction. Despite the sintering process, which typically involves densification of the material, a pore volume fraction of 8.45 % remains, which influences the mechanical properties. Although FFF316L has lower elastic modulus and tensile strength values compared to cold-rolled 316L, its ductility is still competitive. The study further reveals that deformation-induced martensite forms at the intersections of the deformation twins and ferrite islands form at the grain boundaries during the compression and sintering phases. These findings highlight the challenges associated with FFF316L in specific application fields and signal the need to continue to carefully evaluate and improve the development of manufacturing technologies. T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024 CY - Berlin, Germany DA - 12.06.2024 KW - Additive manufacturing KW - Fused Filament Fabrication KW - Computed Tomography KW - 316L Stainless Steel KW - Deformation-Induced Martensite PY - 2024 AN - OPUS4-60302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayerlein, Bernd T1 - PMD core ontology: Building Bridges at the Mid-Level – A Community Effort for Achieving Semantic Interoperability in Materials Science N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific. This poster presents an approach to create and maintain a comprehensive and intuitive MSE-centric terminology by developing a mid-level ontology–the PMD core ontology (PMDco)–via MSE community-based curation procedures. The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications. T2 - TMS - Specialty Congress 2024 CY - Cleveland, Ohio, US DA - 16.06.2024 KW - Interoperability KW - Semantic Interoperability KW - Digtial Representation KW - Knowledge graph and ontologies PY - 2024 AN - OPUS4-60378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin T1 - Bestimmung von Korrosionsabträgen an Zink mittels gelartiger Elektrolyte N2 - Das Poster zeigt eine Methode zur Bestimmung von Korrosionsraten und Korrosionsabträgen an Zink durch Verwendung von gelartigen Elektrolyten. T2 - Jahrestagung 2016 der GfKORR CY - Frankfurt/Main, Germany DA - 15.11.2016 KW - Gelartige Elektrolyte KW - Gel-type electrolytes KW - Verzinkungen KW - Zinc coatings KW - Korrosionsabtrag KW - Corrosion loss PY - 2016 AN - OPUS4-38298 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinemann, Steffi T1 - Untersuchung des Einflusses industrieller Korundschleifprozesse auf die Korrosionsbeständigkeit nichtrostender Stähle mittels KorroPads N2 - Das Poster stellt aktuelle Eregbnisse des AiF-Vorhabens 18823 N/1 zum Einfluss von Schleifprozessen auf die Korrosionsbeständigkeit nichtrostender Stähle vor. T2 - Jahrestagung 2016 der GfKORR CY - Frankfurt/Main, Germany DA - 15.11.2016 KW - Korrosion KW - Corrosion KW - Korundschleifen KW - Corundum grinding KW - Nichtrostende Stähle KW - Stainless steels PY - 2016 AN - OPUS4-38299 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Madkour, Sherif T1 - Evidence of a three-layred structure in ultrathin PVME and PVME-PS blend films by nanosized relaxation spectroscopy N2 - In the course of miniaturizing modern technology down to the molecular scale, much remain unknown about the materials behavior and the deviations from the bulk that might arises from confinement effects. Here, a combination of nano-sized relaxation spectroscopies (Broadband dielectric spectroscopy (BDS) and Specific heat spectroscopy (SHS); employing AC nanochip calorimetry) were utilized to investigate the glassy dynamics of ultra-thin films of Poly (vinyl methyl ether) (PVME) and of blends PVME / Polystyrene (PS) 50:50 wt-%,, which are miscible in bulk (thicknesses: ca. 8 nm – 160 nm, film thickness was controlled by ellipsometry, film topography by AFM). Both methods are sensitive to different probes; where SHS senses entropy fluctuations while BDS measures dipole fluctuations. For BDS measurements, a recently developed nano-structured electrode sample arrangement is employed, where ultra-thin films are spin-coated on an ultra-flat highly conductive silicon wafer, sandwiched between a wafer with nanostructured SiO2 nano-spacers with heights between 35 nm and 70 nm. For PVME films, two thickness independent processes were observed and interpreted to be the α-processes of a bulk-like layer and a process due to an absorbed layer to the substrate. This adsorbed layer further undergoes a confinement effect that results in the localization of the segmental dynamics, which results in an Arrhenius-like temperature dependence. A detailed analysis of the dielectric strengths of both processes reveals that the thickness of the adsorbed layer decreases with increasing temperature, while that of the bulk-like layer increases. For the blend system, by measuring the dynamic Tg in dependence of the film thickness, SHS showed that the Tg of the whole film was strongly influenced by a nanometer-thick surface layer at the polymer/air interface due to a self-assembling process. The dynamic Tg obtained from the SHS measurements decreased with decreasing film thickness. On the other hand, BDS measurements showed a completely different behavior. At high temperatures, the temperature dependence of the relaxation times of the films follows that of bulk-like PS/PVME; obeying the VFT-law. With decreasing temperature, the temperature dependence deviates from the VFT to an Arrhenius law; where the apparent activation energy decreases with decreasing film thickness. This is the first example where confinement induced changes were observed by BDS for ultra-thin films. All results were analyzed in detail in a comprehensive discussion. T2 - Polydays 2016 CY - Potsdam, Germany DA - 28.09.2016 KW - Ultra-Thin films PY - 2016 AN - OPUS4-38188 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bettge, Dirk A1 - Sonnenburg, Elke A1 - Klinger, Christian T1 - Metallographische Zielpräparation von Ungänzen im Zusammenspiel mit ZfP-Methoden N2 - Oft sind von außen nicht sichtbare „Ungänzen“ im Innern die Ursache für das Versagen von Bauteilen. In manchen Fällen genügt eine herkömmliche metallographische Präparation, um der Schadensursache auf die Spur zu kommen. In anderen Fällen aber sind die Ungänzen zu klein oder ihre Lage zu ungewiss, um sie mit zufälligen Schnitten zu treffen. Zudem würde man durch Fehlversuche das Bauteil zu stark schädigen und so wertvolle Spuren verlieren sowie die weitere Untersuchbarkeit einschränken. In solchen Fällen ist es im wahrsten Sinn des Wortes zielführend, die Ungänzen mit Hilfe eines räumlich abbildenden ZfP-Verfahrens zu lokalisieren und dann mit den erhaltenen Koordinaten eine metallographische Zielpräparation präzise durchzuführen. Als Methoden kommen z.B. Mikro-Computer-Tomographie (µCT) und Tauch-Ultraschall in Frage. Bauteile können kleine elektronische Komponenten sein, aber auch große Bauteile wie Wellen aus Fahrzeugen oder Anlagen. T2 - Metallographietagung 2016 CY - Berlin, Germany DA - 21.09.2016 KW - Metallographie KW - ZfP KW - Schadensanalyse PY - 2016 AN - OPUS4-38190 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bettge, Dirk A1 - Sturm, Daniel A1 - Goldbeck, Hennig T1 - Metallographische Untersuchungen an gebrochenen Hüftprothesen mit Schaftadapter N2 - Modulare Hüftprothesen können individuell der Anatomie des Patienten angepasst werden und haben dadurch eine positive Auswirkung auf dessen Lebensqualität. Unter Betriebsbelastung sind in der zusätzlichen Konusverbindung zwischen Schaft und Kopfteil Relativbewegungen möglich. Selbst an Titan-Bauteilen bewirken diese durch Verletzung der Passivschicht Reibkorrosion und infolgedessen Spaltkorrosion. Verunreinigungen wie z.B. Knochenrückstände in der Konusverbindung bewirken eine erhöhte Relativbewegung und führen zusätzlich zu einer örtlichen Spannungsüberhöhung durch lokale Pressung. Die an der Mantelfläche des Schafts entstehenden Korrosionsdefekte reduzieren die Schwingfestigkeit des Schafts erheblich, so dass dort Schwingrisse initiiert werden können, welche dann durch die üblichen zyklischen Schwell-Biegebelastungen bis zum Restgewaltbruch wachsen. T2 - Metallographietagung 2016 CY - Berlin, Germany DA - 21.09.2016 KW - Metallographie KW - Fraktographie KW - Schadensanalyse PY - 2016 AN - OPUS4-38191 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosu, Dana-Maria T1 - The accuracy and reproducibility in thickness determination of thin films using SE N2 - Maintaining a consistent product quality is critical for the thin film industry. Therefore, the development of highly accurate protocols able to detect variations and nonidealities in manufactured thin film devices is essential and helps improve production quality and decrease manufacturing costs. The present work will discuss the accuracy and reproducibility in the determination of the thickness of thin films relevant for optoelectronic industry using spectroscopic ellipsometry, starting with the importance of set-up calibration, the need for very well defined calibration standards suitable for real devices and not least, the importance of accurate data analysis. As ellipsometry is an indirect method and theoretical modelling is needed to obtain the desired information regarding the investigated samples (e.g. thickness, roughness, optical constants), the model uncertainty has to be discussed and taken into account. If for ideal samples consisting of single layers with well-known optical constants the determination of thickness and roughness is straight forward and pretty accurate, for real samples, more complex theoretical models are needed and extracting accurate information regarding the samples can be very challenging. With careful calibration and a multidisciplinary approach, a combined measurement methodology can be developed enabling reliability, comparability, and accuracy. For production-relevant operation, maintaining the ease of use and scalability of ellipsometry as a technique can also be retained. T2 - EOSAM (European Optical Society Annual Meeting) CY - Berlin, Germany DA - 26.09.2016 KW - Spectroscopic ellipsometry KW - Thin films KW - Film thickness determination KW - Uncertainty PY - 2016 AN - OPUS4-38109 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Veliz Montes, Cinthya T1 - Unsubstituted, covalently-linked phthalocyanine-C60 fullerene dyads N2 - Were prepared four unsubstituted Pc - C60 fullerene systems, using two different synthetic strategies, via Prato (1,3 - dipolar cycloaddition) or Bingel reactions. The precursor Pcs 1 and 2 were successfully synthesized by cyclotetramerization reaction between TBDPS - protected and unsubstituted phthalonitriles. The surface studies are currently ongoing. T2 - PcsTT2016 Symposium CY - Elche, Spain DA - 27.01.2016 KW - Fullerene KW - Phthalocyanine PY - 2016 AN - OPUS4-38556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lüth, Peter T1 - CEQAT-DGHS Ringversuchsprogramm der BAM in Kooperation mit QuoData und PTB N2 - Bei der Bewertung der Verlässlichkeit der im Labor gewonnenen Prüfergebnisse spielen Ringversuche eine entscheidende Rolle. Die Bundesanstalt für Materialforschung und -prüfung (BAM) unterstützt deshalb den weiteren Ausbau des Ringversuchsprogramms des im Jahr 2007 gegründeten Kompetenzzentrums zur Qualitätssicherung für Prüfungen von Gefahrgütern und Gefahrstoffen auf physikalische Gefahren (Centre for quality assurance for testing of dangerous goods and hazardous substances, CEQAT-DGHS). Bei allen bisher untersuchten Prüfmethoden besteht ein Verbesserungsbedarf. Die RV müssen daher zunächst auf die Methodenentwicklung, -verbesserung und -validierung abzielen und nicht auf Leistungstests. T2 - 14. Kolloquium zur chemischen und physikalischen Sicherheitstechnik (BAM-PTB-Kolloquium) CY - Berlin, Germany DA - 14.06.2016 KW - Gefahrgut KW - Gefahrstoff KW - Ringversuch KW - Prüfmethode KW - Validierung KW - Qualitätssicherung PY - 2016 AN - OPUS4-38465 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hemmleb, M. A1 - Bettge, Dirk A1 - Berger, D. A1 - Driehorst, I. T1 - 3D surface reconstruction with segmented BSE detector: New improvements and application for fracture analysis in SEM N2 - Application of 4Q-BSE detector and dedicated software enables 3D surface measurements of fracture samples in SEM. 3D surface measurement is independent from magnification and material invariant. Quantitative height measurements require careful detector adjustment and system calibration. Live 3D view allows a fast assessment of topographical features. In addition to SE and BSE imaging, 3D surface data help to analyse and interpret fracture samples. T2 - European Microscopy Congress 2016 CY - Lyon, France DA - 28.08.2016 KW - Topography KW - SEM KW - 3D analysis KW - Fractography PY - 2016 AN - OPUS4-38456 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epping, Ruben T1 - Characterization of statistical EO-PO copolymers containing different end groups by UPLC/ESI-MS N2 - Commercial statistical ethylene oxide (EO) and propylene oxide (PO) copolymers of different monomer compositions and different average molar masses were studied by liquid chromatography under critical conditions (LCCC). Theoretical predictions of the existence of a critical adsorption point (CPA) for statistical copolymers with a given chemical and sequence distribution, could be studied and confirmed. An improved way to determine these critical conditions in a copolymer, alongside the inevitable chemical composition distribution (CCD), with the aid of mass spectrometric detection is described. Shift of the critical eluent composition with the monomer composition of the polymers could be observed. Due to the relatively low average molecular weight, broad molecular weight distribution (MWD) and the presumed existence of different end group functionalities as well as sequence distribution, gradient separation only by CCD was not possible. Therefore isocratic separations at the CPA of definite CCD’s were applied. Although the various present distributions partly superimposed the separation process the goal of separation by end group functionality could still be achieved on the basis of the additional dimension of ESI-MS. The existence of HO-H besides the desired AllylO-H end group functionalities could be confirmed and their amount could be estimated. T2 - International Symposium GPC/SEC and Related Techniques CY - Amsterdam, The Netherlands DA - 26.09.2016 KW - Polymers KW - UPLC KW - ESI-TOF-MS PY - 2016 AN - OPUS4-37632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schade, U. T1 - Estimation of THz waveforms for material characterization of stratified objects N2 - The poster discusses theoretically and exemplarily the influence of the materials and experimentally selected situation on the shape and size deformation of a detected pulse signal previously reflected on a three layer sheet. T2 - 41st International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz 2016) CY - Copenhagen, Denmark DA - 25.09.2016 KW - THz spectroscopy KW - Pulse reflection KW - Pulse shape analysis KW - Optical layer model PY - 2016 AN - OPUS4-37639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yildirim, Arda T1 - Structure and dynamics of 2,3,6,7,10,11-hexakis[hexyloxy] triphenylene in nanoporous anodic aluminum oxide membranes N2 - Due to their chemical structure, a rigid disk-like aromatic core and flexible alkyl chains attached to the core, discotic liquid crystals (DLCs) can organize and stack themselves into columns in a hexagonal columnar mesophase, a mesophase in between the plastic crystalline and isotropicphase. The overlap of the π orbitals of the aromatic core in the hexagonal columnar mesophase leads to a high charge-carrier mobilitie along the column axis – these columns can be considered as “moleculer nanowires” making liquid crystals a promising class of materials for electronic applications. Previous studies on DLCs showed that the phase behavior of DLCs is susceptible to nano confinement. Here in this study, the thermotropic collective orientational order of 2,3,6,7,10,11 hexakis[hexyloxy] triphenylene (HAT6), a triphenylene based DLC, and the effects of nano confinment on of its phase behavior were investigated by broadband dielectric spectroscopy (BDS) and differential scanning calorimetry (DSC). HAT6 was embedded into nanoporous anodic aluminum oxide membranes by melt infiltration in the isotropic phase under argon atmosphere. The filled membranes have the thickness of 80 µm and the diameter of 15mm and parallel aligned tubular nanopores having the pore diameters of 25, 40, 80 and 180 nm. The filling degree for each sample was checked by thermogravimetric analysis (TGA) in order to ensure complete filling. The bulk HAT6 forms, a hexagonal columnar phase between the isotropic phase above 371 K, and the plastic crystalline phase below 340 K. Unlike the bulk, the confined HAT6 forms two peaks in the heat flow during the plastic crystalline-to-hexagonal columnar phase transition, which might be the evidence of two different phase structures close to the wall and in the pore center. Moreover, the isotropic-to-columnar transition of the confined HAT6 shifts with decreasing pore diameter to lower temperatures. T2 - 9th International Conference on Broadband Dielectric Spectroscopy and its Applications CY - Pisa, Italy DA - 11.09.2016 KW - Discotic liquid crystals PY - 2016 AN - OPUS4-37712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus T1 - Degradation of PE-HD induced by liquid media - FNCT testing N2 - The Full-Notch Creep Test (FNCT) is widely used to characterize the slow crack growth (SCG) behavior of polyolefin materials in “inert” media as well as effects of environmental stress cracking (ESC) in which the medium has decisive influence on damage mechanism and time to failure tf*. Usually the FNCT is applied as a standardized testing method (ISO 16770) using a few universal liquid media, such as solutions of Arkopal N 100 (detergent). Selected relevant PE-HD materials are investigated also in real media and influences of temperature and geometry of specimen and notch are explicitly addressed. The investigations comprise also the ESC behavior of PE-HD in media that are sorbed to a significant extent – such as Diesel and Biodiesel – based on comparison with samples previously saturated with those media. T2 - PolyDays 2016 CY - Potsdam, Germany DA - 28.09.2016 KW - Sorption KW - Environmental stress cracking KW - Slow crack growth KW - PE-HD KW - FNCT PY - 2016 AN - OPUS4-37716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin T1 - Corrosion investigations by using gel-type electrolytes N2 - In the presentation different zinc coatings are presented and investigated. Their naturally formed protective layers are electrochemically characterized and corrosion relevant values are determined by using a gel pad based on polysaccharide. The corrosion relevant values allow the differentiation of various zinc coating systems and can describe the current protective effect provided by the coating. It is shown that gel-type electrolytes influence protective layers and coatings considerably less than corresponding bulk electrolytes. From the results it is evident that gel-type electrolytes represent a viable and promising field in corrosion research.zeige mehr T2 - EUROCORR European Corrosion Congress 2016 CY - Montpellier, France DA - 11.09.216 KW - Corrosion investigations KW - Gel-type electrolytes KW - Zinc coatings PY - 2016 AN - OPUS4-37496 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Plarre, Rüdiger T1 - Invasoren im Kleiderschrank N2 - Die Kleidermotte wird als invasive Art (Neozoon) beschrieben. T2 - Lange Nacht der Wissenschaften, FU Berlin, FB Biologie CY - Berlin, Germany DA - 11.06.16 KW - Kleidermotte KW - Invasive Arten KW - Neozoon PY - 2016 AN - OPUS4-36964 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fontana, Patrick T1 - Beton mit funktionalen Oberflächen N2 - Beton ist als Massenbaustoff vielseitig einsetzbar. Eine der neuesten Entwicklungen ist Ultrahochleistungsbeton (UHPC). Seine besonderen Eigenschaften ermöglichen eine zusätzliche Funktionalisierung der Oberflächen, da annähernd beliebige Mikrostrukturen exakt abgeformt werden können. So lassen sich beispielsweise Fassadenelemente aus UHPC bereits bei ihrer Herstellung im Betonfertigteilwerk mit selbstreinigenden Oberflächen ausrüsten. Eine andere Möglichkeit ist eine Anwendung als Datenspeicher. Wie das Beispiel der Schallplatte aus UHPC zeigt, lassen sich Muster, die hier die Schallinformationen enthalten, exakt von einer Matrize kopieren. T2 - Lange Nacht der Wissenschaften 2016 CY - Berlin, Germany DA - 11.06.2016 KW - UHPC KW - Selbstreinigung KW - Datenträger KW - Betonschallplatte PY - 2016 AN - OPUS4-36948 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bradley, I. A1 - Otremba, Frank A1 - Birk, A. M. A1 - Bisby, L. T1 - Novel equipment for the study of pressure vessel response to fire N2 - Pressurisation of full-containment pressure vessels in fire is known to be driven by thermal stratification. The predominant mode of heat transfer to the contents (convection from the shell to the liquid phase) results in formation of „hot“ boundary layers. Sub-cooled boiling may also be present. The warm layer rises to the surface through buoyancy and bubble flow, increasing the surface of the liquid above that of the bulk temperature, and hence driving a pressure rise. For reliable prediction of the complex effects governing vessel pressurization a three-dimensional numerical model is required. Work is being undertaken on such a model by other institutions in cooperation with this project. T2 - ASME 2016 CY - Phoenix, Arizona, USA DA - 11.11.2016 KW - Vessels KW - Novel equipment PY - 2016 AN - OPUS4-38433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cabeza, Sandra T1 - Low alloyed Mg-Y/RE-Zn alloys: mechanical and corrosion behaviour N2 - Mg-Y,RE-Zn systems present second phases with high thermal stability, promoting the increase of strength and creep resistance at high temperatures. Mg and its alloys have a potential application as biomaterials due to their biocompatibility and degradation behaviour. The dominant corrosion mechanism in those alloys is the microgalvanic corrosion through coupling of the more noble second phases with the Mg matrix, and therefore a low concentration of those was sought. T2 - Mg 2015 CY - Jeju, South Korea DA - 12.10.2015 KW - Magnesium KW - LPSO KW - Corrosion behaviour KW - Mechanichal behaviour PY - 2015 AN - OPUS4-38398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Otremba, Frank A1 - Sklorz, Christian T1 - A new tank design for Hazmat N2 - Initial studies have shown pre-deformed honeycomb structure pressure vessels to have comparable burst pressure to straight steel vessels. It was shown that honeycomp structured tanks have a higher energy absorption than straight steel tanks. Future studies will investigate optimization of the deformed plate, to determine if increased payloads or a reduced wall thickness can be achieved. T2 - ASME 2016 International Mechanical Engineering Congress and Exposition (ICME 2016) CY - Phoenix, Arizona, USA DA - 11.11.2016 KW - Hazmat KW - Tankdesign KW - Honeycomb structure PY - 2016 AN - OPUS4-38399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönfelder, Thorsten A1 - Otremba, Frank T1 - Temperature distribution during filling of a composite receptacle N2 - The arrangement of the measuring sensors allowed the capture of air flow induced temperatures and material temperatures on various points of the cylinder body. Four significant temperature levels could be observed: Inside the cylinder (far from the wall, close to the wall), inside the aluminium liner and outer surface. Figure 5 shows the temperature distribution after a regular filling process with a filling time of ten minutes. The temperature sensors T1 - T9 are marked with different colors. The corresponding measurement points are shown in Figure 4. Due to the high thermal conductivity of the aluminum liner the induced temperature peaks are quickly derived. A flow-induced exceeding of the maximum approval temperature is not expected. Regarding the safety assessement the results show that the pressure and temperature profilesmustbe taken into account. T2 - ASME 2016 International Mechanical Engineering Congress and Exposition (IMECE2016) CY - Phoenix, Arizona, USA DA - 11.11.2016 KW - Distribution during filling KW - Type III composite pressure receptacles PY - 2016 AN - OPUS4-38404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sojref, Regine A1 - Nofz, Marianne T1 - Thin and porous sol-gel alumina coatings on a 9% Cr steel as a protection against high-temperature corrosion in power plants N2 - In order to reduce CO2 emissions fossil fuelled power stations with high combustion efficiency are being developed. The increase of the operating temperature, a common way to improve combustion efficiency, leads to enhanced corrosion of heat exchange steel tubes in the power plants. Within the framework of the European project “Production of Coatings for New Efficient and Clean Coal Power Plant Materials” (POEMA)", high temperature corrosion protection coatings are now under investigation. Thin porous sol-gel alumina films are promising candidate coating materials. Coatings were prepared by applying boehmite sols on grinded steel P92 and subsequent heat treatments at temperatures up to 650 °C. Thus a porous layer of worm-like particles was formed consisting of nano-crystallites and amorphous alumina. A dense interface with satisfying adhesion resulted from diffusion of chromium and iron ions out of the steel into the porous coating. However, the film locally exhibited some cracks caused by steep edges in the grinded steel surface. An appropriate substrate pretreatment should avoid this problem. The protection of the steel relies on the barrier function of the alumina coating and the formation of a dense chromia layer at the steel surface. T2 - ICC6 6th International Congress on Ceramics CY - Dresden, Germany DA - 21.08.2016 KW - High-temperature corrosion KW - Alumina KW - Chromium PY - 2016 AN - OPUS4-38354 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fischer, Franziska T1 - In situ investigation of the mechanochemical formation of cocrystals unsing combined PXRD and Raman spectroscopy N2 - We present an in situ investigation of the mechanochemical formation of cocrystals using synchrotron XRD and Raman spectroscopy. This combination allows to study milling processes on the level of the molecular and crystalline structure thus obtaining reliable data for mechanistic studies. Thereby, mechanochemical syntheses can be optimized to isolate new crystal structures. T2 - Joint BER II and BESSY II User Meeting 2016 CY - Berlin, Germany DA - 07.12.2016 KW - Intermediate KW - Mechanochemistry KW - Cocrystal KW - In situ KW - Milling PY - 2016 AN - OPUS4-38722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -