TY - CONF A1 - Magkos, Sotirios T1 - Reconstruction of limited-angle projection data with DIRECTT N2 - Direct Iterative Reconstruction of Computed Tomography Trajectories is a fully three-dimensional algorithm that prioritizes the reconstruction of voxels corresponding to dominant trajectories across the projections. T2 - MUMMERING outreach conference CY - Online meeting DA - 10.06.2021 KW - Iteration method KW - X-ray imaging KW - Signal processing KW - Computed tomography PY - 2021 AN - OPUS4-53466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Widjaja, Martinus Putra A1 - Alves, M. A1 - Mavrogordato, M. A1 - Joannes, S. A1 - Bunsell, A. A1 - Mair, Georg W. A1 - Thionnet, A. T1 - Effect of the Time Dependent Loading of Type IV Cylinders Using a Multiscale Model N2 - The Reduced Volume Method (RVM) has been used to evaluate the multiscale fibre break model developed at Mines ParisTech. It allows the model to be assigned only at certain part of the structures without necessarily compromising the final prediction. An attempt to model a simple unidirectional composite structure has also been carried out and gave a satisfying result. This paper deals with the application of the RVM to real scale type IV composite cylinders, where its stacking sequence was evaluated through micro-CT scans conducted with the collaboration of the University of Southampton. Two modelling geometries were evaluated and compared with the corresponding experimental results. T2 - 8th International Conference on Hydrogen Safety (ICHS) CY - Adelaide, Australia DA - 24.09.2019 KW - Fibre break KW - Multiscale modelling KW - Type IV pressure vessel KW - Time dependent loading PY - 2019 SP - ID131 AN - OPUS4-49273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. T1 - Evidence of damage evolution during creep of Al–Mg alloy using synchrotron X-ray refraction N2 - In order to provide further evidence of damage mechanisms predicted by the solid-state transformation creep (SSTC) model, direct observation of damage accumulation during creep of Al–3.85Mg was made using synchrotron X-ray refraction (SXRR). X-ray refraction techniques capture the specific surface (i.e. surface per unit volume) with a field of view comparable to the specimen size but with microscopic sensitivity. A significant rise of the internal specific surface with increasing creep time was observed, providing evidence for the creation of a fine grain substructure, as predicted by the SSTC model. T2 - Tenth Joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 05.12.2018 KW - Aluminium alloys KW - Creep KW - Damage KW - Synchrotron X-ray refraction KW - Electron microscopy KW - Subgrain structure PY - 2018 AN - OPUS4-46861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Glass-ceramic composite multilayer structures - modeling of densification and shrinkage mismatch N2 - Low temperature co-fired ceramics (LTCC) are glass-ceramic composites that are processed by tape casting and multilayer technology to create multilayer circuit boards and electronic packages for high frequency applications, microsystems, and sensors. Pressure-assisted sintering (PAS) enables the densification of LTCC without lateral shrinkage, and thereby the manufacturing of miniaturized modules with minimal shrinkage tolerances. Co-firing of LTCC with other functional ceramics facilitates the implementation of innovative module concepts. The master sintering curve model is a useful tool to supplement the empirical optimization of such sintering processes. Two applications of the model are presented. Firstly, an algorithm is deduced that allows the simulation of shrinkage mismatch in a combined multilayer structure. Based on this simulation, an optimized process for the co-firing of LTCC and ferrite is derived. Secondly, the pressure-assisted sintering of LTCC is modeled. A comprehensive description of the densification behavior of LTCC during PAS is thereby possible. T2 - 14. Treffen des DGG-DKG Arbeitskreises "Glasig-kristalline Multifunktionswerkstoffe" CY - Berlin, Germany DA - 25.02.2016 KW - low temperature co-fired ceramics KW - master sintering curve KW - pressure-assisted sintering KW - multilayer PY - 2016 AN - OPUS4-35419 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Tailoring the surface properties of glass-ceramic-composite substrates by advanced pressure-assisted sintering T2 - Junior Euromat 2012 CY - Lausanne, Switzerland DA - 2012-07-23 PY - 2012 N1 - Geburtsname von Mieller, Björn: Brandt, B. - Birth name of Mieller, Björn: Brandt, B. AN - OPUS4-26398 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Widjaja, Martinus Putra T1 - General update of the PhD work for mid_term consortium meeting N2 - Before the multiscale model is used to calculate real scale composite structures, a study to improve the effectiveness is required, especially the computation time. The reduced volume method has been studied and proved to be useful for the multiscale model of Mines ParisTech. T2 - Mid_Term Consortium Meeting of FiBreMoD CY - Imperial College London, United Kingdom DA - 11.09.2018 KW - Reduced volume method KW - Integral range KW - Composite pressure vessels KW - Multiscale model KW - Fibre breaks PY - 2018 AN - OPUS4-48570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. T1 - Microstructure characterization of materials using X-ray refraction techniques N2 - X-ray refraction is an excellent tool for the characterization of the microstructure of materials. However, there are only a few (synchrotron) laboratories in the world that use this technique for material characterisation. Therefore, the seminar will first explain the basic principles of X-ray refraction and the measurement techniques installed at the hard X-ray beamline BAMline at BESSY II (Berlin, Germany). This is followed by examples of investigations on fibre-reinforced plastic composites (CFRP) as well as ceramic (Cordierite, ZrO2-SiO2) and metallic materials (Ti-6Al-4V, Inconel). Some of the investigations were carried out both ex-situ and in-situ under mechanical and thermal load. The results are correlated with the mechanical properties of the materials. T2 - LNLS Users Group Seminar Series CY - Campinas, Brasil DA - 25.10.2022 KW - X-ray refraction KW - Analyzer-Based Imaging KW - BAMline PY - 2022 AN - OPUS4-56117 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander T1 - Residual stresses in am review and oulook of activities at BAM N2 - Critical discussion of residual stress Analysis in additive manufacturing from examples in literature and an overview of activities at BAM T2 - Workshop on Fatigue of Additive Manufactured Metallic Components CY - BAM, Berlin, Germany DA - 16.05.2019 KW - Diffraction KW - Additive Manufacturing KW - Residual stress PY - 2019 AN - OPUS4-49843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evsevleev, Sergei T1 - Stress partitioning and damage evolution in near-eutectic cast AlSi12CuMgNi alloy N2 - Near eutectic cast Al–Si alloys are the basis of all Al-alloys used for pistons due to their high fluidity and relatively high strength-to-weight ratio. Their microstructure is characterized by the presence of eutectic-Si embedded in an age hardenable -Al matrix. During solution heat treatment, the eutectic Si network undergoes a process of gradual disintegration, reducing the load bearing capability and the strength of the alloy. The improvement of the high temperature strength is achieved by addition of transition elements such as Cu, Mg or Ni through the formation of stiff intermetallic (IM) phases. In present study a near-eutectic AlSi12CuMgNi alloy produced by squeeze casting was investigated in as-cast condition. The in-situ neutron diffraction compression tests revealed the stress partitioning mechanism between phases of the alloy. Large stresses were found in IMs, showing their significant role as a reinforcement elements. After the failure of IM and Si phases the load is transferred back to the Al matrix, inducing further plastic deformation in it, yet without creating microcracking. The neutron diffraction experiments were coupled with assessment of internal damage after ex-situ compression tests by synchrotron radiation computed tomography. The quantitative analysis of CT data revealed that local tensile stresses in IM and Si phases induce microcracks with preferential orientation, parallel to the axis of applied load. Altogether, present experimental data was used as an input for the developed micromechanical model based on Maxwell homogenization scheme. In contrast to the neutron diffraction experiment, which can only determine stress differences between the axial and radial sample directions, the model allows predicting the principal stresses in each phase of the alloy. T2 - European Conference on Residual Stresses - ECRS10 CY - Leuven, Belgium DA - 11.09.2018 KW - Aluminum alloy KW - Intermetallics KW - Computed tomography KW - Neutron diffraction KW - Stress analysis KW - Load partition PY - 2018 AN - OPUS4-46054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Material development for oxide multilayer generators N2 - Thermoelectric generators can be used for energy harvesting by directly transforming a temperature gradient into a voltage. Multilayer generators based on low-temperature co-fired ceramics technology (LTCC) are an interesting alternative to conventional π-type generators. They exhibit several advantages like high filling factor, possibility of texturing, co-firing of all materials in one single-step, and reduction of production costs due to the high possible degree of automation. Pressure-assisted sintering enables the theoretical possibility of co-firing two promising oxide thermoelectric materials: Ca3Co4O9 (p-type) and CaMnO3 (n-type). Due to the large difference in sintering temperature (300 K) the process is very challenging. In this work we show the material development of Ca3Co4O9, CaMnO3, insulation and metallization for multilayer generators co-fired under pressure at 900 °C. The materials are tailored regarding their sintering behavior, electrical performance and coefficients of thermal expansion. Different generator designs (unileg and pn-type) were fabricated and analyzed regarding crack formation, interaction layers and thermoelectric performance. Simulated stresses during cooling in the multilayers are compared with actual crack formation for different sintering conditions. This study shows that a lower pressure level and a lower level of complexity are beneficial for co-firing and performance. T2 - 45th International Conference and Expo on Advanced Ceramics and Composites (ICACC 2021 Virtual) CY - Online meeting DA - 08.02.2021 KW - Thermoelectrics KW - Multilayer PY - 2021 AN - OPUS4-52462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Powierza, Bartosz T1 - In-situ CT observation of water migration in heated concrete N2 - In order to study damage in concrete exposed to fire, a series of continuous X-ray computed tomography (CT) measurements were performed on a concrete sample heated, in-situ, on one side. The water migration relative to time and 3D space and, in particular, the dynamic condensation and vaporization of water droplets in the pores was quantified. This approach shows significant potential for further investigation of fire-related concrete damage. T2 - 3rd International Conference on Tomography of Materials and Structures CY - Lund, Sweden DA - 26.06.2017 KW - In-situ KW - X-ray CT KW - Heated concrete KW - Pores KW - Water migration KW - Fire PY - 2017 UR - http://meetingorganizer.copernicus.org/ICTMS2017/ICTMS2017-29.pdf AN - OPUS4-43062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hassenstein, Christian T1 - Automated self-adjustment of array probe with a robotic ultrasonic test system N2 - Ultrasonic testing (UT) of objects with complex geometries often requires the use of a robotic arm to position the probe perpendicular to the local surface. Using immersion makes it possible to test these objects with standard ultrasonic linear array probes. Here, the probe positions and orientations provided by the robot are used for merging the locally acquired image data into a 3D-reconstruction. The quality of this reconstruction is highly dependent on the alignment of the tool center point (TCP) of the physical probe with the TCP used in the digital model. For common industrial tools, the TCP is usually acquired using geometric features of the tools. However, for ultrasonic arrays in immersion, there is a water standoff between the probe and the test object, therefore the TCP is in free space in front of the array and cannot be acquired with the common method. To overcome this challenge, we propose a method that allows the robotic ultrasonic system to automatically self-adjust the positioning of the UT probe using a test block made of steel with defined geometric features as a target for referencing. For each of the six degrees of freedom, a scan and adjustment routine are established using the data acquired by the UT probe to update the TCP’s position and orientation in the robot control. Given a coarse pre-definition of the TCP and the known target test block, no human interaction is required while the system determines the optimum tool position and orientation. Part of this work will be used to improve and extend standards for robotic ultrasonic test systems, e.g. ISO 24647. T2 - 20th World Conference On Non-Destructive Testing CY - Incheon, South Korea DA - 27.05.2024 KW - Ultrasonic KW - Testing KW - Automation KW - Robotics KW - NDT 4.0 PY - 2024 AN - OPUS4-60565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - Influence of the pressure difference on the safety characteristics of dusts and potential ignition sources for hybrid mixtures N2 - In the standards for the determination of safety characteristics of dusts an initial pressure difference of 400 mbar (all: abs) is applied, that increases to 1013 mbar to achieve a homogeneous dust-air mixture. Since the measuring equipment accuracy is given with ± 0,1 bar the initial pressure could range somewhere between 300 and 500 mbar and the pressure increase between 500 and 700 mbar, leading to a testing pressure of 800 to 1200 mbar. This variation does not only affect the testing pressure but also the concentration of dust and the level of turbulence, leading to wrong values of Pmax, Kst and assigning them to wrong concentrations. When tests for hybrid mixtures are conducted there are more degrees of freedom leading to even higher variations. To overcome these variations a higher accuracy is demanded for hybrid mixture testing. Further, in this presentation four standardized ignition sources are presented. T2 - Global Dust Safety Conference CY - Halifax, Canada DA - 01.03.2021 KW - hybrid mixtures, ignition sources, safety characteristics PY - 2021 AN - OPUS4-53557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hassenstein, Christian T1 - Automatisierte Wanddickenbestimmung an Prüfteilen mit komplexen Geometrien aus anisotropen Werkstoffen N2 - Im Rahmen des Projektes MRO2.0, das sich mit der digitalen Transformation des Servicezyklus von modernen Gasturbinenschaufeln beschäftigt, wurde gezeigt, wie sich automatisiert und flächendeckend die (Rest-)Wanddicke an variabel gekrümmten Prüfgeometrien bestimmen lässt. Es wurde ein Roboterarm verwendet, der ein lineares Ultraschallarray in Tauchtechnik führt und Prüfdaten aufnimmt, die mit einer adaptierten TFM (Total Focusing Method) zu Rekonstruktionen der Außen- und Innenoberfläche verarbeitet werden. In der aktuellen zweiten Projektphase wird die Methode für Werkstoffe erweitert, die anisotrope akustische Eigenschaften aufweisen. In diesem Beitrag wird eine Methode vorgestellt, wie sich die Kristallausrichtung bzw. die richtungsabhängige Schallgeschwindigkeit mittels eines linearen Ultraschallarrays bestimmen lässt. Für den Sendefall eines Randelements in Kontakttechnik können dabei Wellen identifiziert werden, die sich parallel zur Prüfkopfapertur im Prüfobjekt ausbreiten und mit der richtungsabhängigen Schallgeschwindigkeit skalieren. Die ermittelte Schallgeschwindigkeitsverteilung kann dann verwendet werden, um die lokale Wanddickenbestimmung für die Anisotropie zu adaptieren. T2 - 6. Workshop Messtechnische Anwendungen von Ultraschall CY - Drübeck, Germany DA - 17.06.2024 KW - Ultraschallprüfung KW - Anisotropie KW - Turbinenschaufel KW - NDT 4.0 PY - 2024 AN - OPUS4-60568 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - Comparative study on standardized ignition sources used for explosion testing N2 - For the determination of safety characteristics of gases, vapors and dusts different types of ignition sources are used in international standards and guidelines. Table 1 compares technical relevant ignition sources with their main features. The paper presents test results of a comparative calorimetric and visual study between four different types of ignition sources. The ignition procedures were analyzed visually with a high-speed camera and electric recordings. In addition to that, the influence of the electrode-orientation, -distance as well as ignition energy on the reproducibility of the exploding wire igniter was tested. The exploding wire is already in use for standardized determination of safety characteristics of gases, first tests on the suitability of the exploding wire igniter for dust testing have been carried out by Scheid et al. Using the exploding wire, the ignition energy can be varied from 2 to 10 000 J (2 x 5 000 J) and thus it could be used for gases, vapors, dusts and hybrid mixtures. Moreover it can be used at high initial pressures and it is the only ignition source with an easily measurable ignition energy release. Furthermore, it does not introduce another chemical reaction into the system. Finally, a proposal for a standard ignition source for explosion tests on hybrid mixtures is derived from the test results. T2 - 13th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions CY - Braunschweig, Germany DA - 27.07.2020 KW - Ignition source KW - Exploding Wire KW - Safety characteristics determination KW - Hybrid mixtures PY - 2020 AN - OPUS4-51691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo T1 - Optical thickness-profiling for fs-laserinduced superficial amorphization and oxide removal on silicon N2 - Amorphization and re-crystallization of polished silicon wafers cut in <111> and <100> orientation were studied after irradiation by single Ti:sapphire femtosecond laser pulses (790 nm, 30 fs) using optical imaging, topographic characterization, and transmission electron microscopy. Spectroscopic imaging ellipsometry (SIE) enabled fast data acquisition at multiple wavelengths and provided experimental data for calculating the amorphous layer thickness profiles with lateral resolution in the micrometer and vertical resolution in the nanometer range based on a thin-film layer model including the topmost native oxide. For a radially Gaussian shaped laser beam and at moderate peak laser fluences above the melting but below the ablation threshold, laterally parabolic amorphous layer profiles with maximum thicknesses of some tens of nanometers were quantitatively derived. Moreover, the threshold fluence of the native oxide removal was quantified. At laser peak fluences closely below the ablation threshold of silicon, SIE is capable to reveal even the laser-induced removal and formation of the native oxide covering the Si wafers under ambient air conditions. The accuracy of these all-optical, non-destructive SIE-based layer thickness assessments is verified experimentally through high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). Along with topographic information obtained by atomic force microscopy (AFM), a comprehensive picture of the oxide removal and superficial re-solidification of silicon after local melting by femtosecond laser pulses can be drawn. T2 - E-MRS Spring Meeting 2025 CY - Strasbourg, France DA - 26.05.2025 KW - Femtosecond laser KW - Laser-induced amorphization KW - Native oxide layer KW - Spectroscopic imaging ellipsometry KW - Transmission electron microscopy PY - 2025 AN - OPUS4-63275 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Bacterial adhesion on ultrashort pulse laser processed surfaces ― more than size matters! N2 - Bacterial biofilms are aggregates of bacterial cells, often attached to a surface and enclosed by a self-produced extracellular matrix which confers increased stress tolerance and resistance to cleaning. Biofilm formation leads to biofouling which gives rise to high costs in numerous technical settings due to biocorrosion and biodegradation. However, biofilms can also be attractive for industrial settings such as wastewater treatment systems or for soil bioremediation processes. Hence, the control of bacterial adhesion to a surface is of major concern. Surface topography strongly influences bacterial adhesion. Therefore, one promising way to achieve bacteria-guiding surfaces lies in the contactless and aseptic large-area laser processing of technical surfaces. We used short and ultrashort pulsed laser systems to generate different surface textures, mainly high-spatial-frequency and low-spatial-frequency laser-induced periodic surface structures, LIPSS (HFSL and LFSL), on Ti, Ti-alloy, steel, and polymers (PET and PE). Pristine (polished) and laser processed samples were subjected to bacterial adhesion experiments with two different Escherichia coli strains and Staphylococcus aureus as test organisms. The bacterial strains differed in their cell wall structure (grampositive vs. gramnegative strains), in size, shape, the occurrence of cell appendages, and in their biofilm forming capabilities. Adhesion patterns were analyzed microscopically and compared regarding the respective test strain and surface topography. Our results revealed that adhesion behavior strongly depends not only on the material’s topography and chemistry, but also on the specific bacterial strain, the presence of cell appendages, and ambient growth conditions. T2 - 13th International Conference on Photoexcited Processes and Applications, ICPEPA-13 CY - Lecce, Italy DA - 14.09.2025 KW - Biofilm KW - Bacterial adhesion KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses PY - 2025 AN - OPUS4-64166 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kaczmarek, D. A1 - Bonse, Jörn T1 - Capabilities and limitations of Sipe’s first principles LIPSS theory: current aspects and directions N2 - This presentation elucidates the fundamentals and capabilities of John E. Sipe’s first principles theory (1983) of laser-induced periodic surface structures (LIPSS), representing an analytical mathematical approach (Green’s formalism) to calculate the absorption of electromagnetic radiation at a microscopically rough surface via the so-called efficacy factor. It includes a discussion of assumptions made in the theory and resulting limitations, such as the restriction to a near-surface layer (the so-called “selvedge”), the lack of any material response, or missing inter-pulse feedback phenomena being relevant in typical multi-pulse irradiation conditions. The influence of the angle of incidence, the polarization direction (s-pol. or p-pol.), the optical properties (dielectric permittivity) of the irradiated materials, as well as its surface roughness and its specific encoding in the theory via a shape factor (s) and a filling factor (f) are addressed. A simplifying mathematical reformulation (without changing the validity range) of Sipe’s theory in the form of 14 complex-valued equations published in 2005 is motivated, as well as the necessity of some minor adjustments for non-normal incident radiation - revealed in a very recent Erratum. Starting with 2009, extensions of the original theory were developed, e.g., the analytical Sipe-Drude model in order to include intra-pulse transient changes of the optical properties of the material. Finite-difference time-domain (FDTD) numerical simulations successfully confirmed in 2012 the validity of the Sipe-Drude approach. Moreover, the FDTD formalism can be extended to sub-surface regions and can be combined with a material response (topography) modelling for iteratively considering inter-pulse feedback phenomena. Finally, we will provide characteristic examples of Sipe’s efficacy factor for typical material classes (metals, semiconductors, dielectrics), we will explain how the results can be interpreted, and line out how the Sipe theory may be extended further. T2 - 12th International LIPSS Workshop CY - Leipzig, Germany DA - 11.09.2024 KW - Laser-induced periodic surface structures (LIPSS) KW - Theory KW - Green's formalism KW - Scattering waves KW - Finite-difference time-domain calculations PY - 2024 AN - OPUS4-61098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser Nanotexturierung von Metalloberflächen zur Reduktion von Reibung und Verschleiß N2 - Die Reduktion von Reibung und Verschleiß in technischen Systemen bietet ein großes Potenzial zur Reduktion von CO2-Emissionen. Dieser Beitrag diskutiert die Erzeugung und tribologische Charakterisierung von Ultrakurzpuls-generierten Nanostrukturen auf Metallen (Stahl, Titan). Besonderes Augenmerk wird dabei auf die Rolle der laserinduzierten Oxidschicht im Zusammenspiel mit verschleißreduzierenden Additiven in ölbasierten Schmiermitteln gerichtet. T2 - Online Abendvortrag beim AWT Härterei- und Werkstoffkreis Bodensee der Arbeitsgemeinschaft Wärmebehandlung + Werkstofftechnik e.V. CY - Online meeting DA - 16.01.2025 KW - Additive KW - Laser-induzierte periodische Nanostrukturen KW - Reibungsreduktion KW - Verschleißreduktion PY - 2025 AN - OPUS4-62432 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voss, Heike T1 - Morphology and regularity of high-spatial frequency laser-induced periodic surface structures (HSFL) on titanium materials N2 - Titanium and its alloys are known to allow the straightforward laser‐based manufacturing of ordered surface nanostructures, so‐called high spatial frequency laser‐induced periodic surface structures (HSFL). These structures exhibit sub‐100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, HSFL were processed on different titanium materials (bulk, film) upon irradiation with near‐infrared ps‐laser pulses (1030 nm wavelength, ≈ 1 ps pulse duration) under different laser scan processing conditions. Here we extend our previous work on chemical analyses of HSFL on titanium materials towards a more detailed morphological and topographical surface characterization. For that, scanning electron and atomic force microscopic images are subjected to a regularity analysis using our self-developed ReguΛarity software. The regularity of the HSFL is assessed with respect to the influences of sample- and laser-related parameters, as well as the imaging method used. T2 - 13th International LIPSS Workshop CY - Enschede, Netherlands DA - 29.10.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Titanium KW - Ultrashort laser pulses KW - Laser processing PY - 2025 AN - OPUS4-64631 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - X-ray emission during ultrashort pulse laser material processing N2 - The unwanted emission of X-rays during ultrashort pulse laser material processing in air was already reported more than 20 years ago for pulse repetition rates in the 1 kHz range [1]. It was stated that an enclosure of the experimental setup is necessary to protect the operator from X-rays. By now, the use of ultrashort pulse laser technology has become established in industry using repetition rates in the multi 100 kHz up to the GHz range and laser average powers up to the kW level. Since 2018/2019, more and more investigations have been carried out on the hazards from X-rays at higher laser pulse repetition rates [2-4]. Recently, maximum X-ray skin dose rates of the order of 1 Sv/h (iron target [5]) and X-ray photon energies of up to 40 keV (tungsten target [6]) were reported. Measures must be taken to shield the unwanted X-rays. T2 - 10th Conference on Applications of Femtosecond Lasers in Materials Science (FemtoMat) CY - Mauterndorf, Austria DA - 24.02.2025 KW - Ultrashort pulse laser KW - Material processing KW - X-ray emission KW - Radiation protection PY - 2025 AN - OPUS4-62665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser Nanotexturierung von Metalloberflächen zur Reduktion von Reibung und Verschleiß N2 - Die Reduktion von Reibung und Verschleiß in technischen Systemen bietet ein großes Potenzial zur Reduktion von CO2-Emissionen. Dieser Beitrag diskutiert die Erzeugung und tribologische Charakterisierung von Ultrakurzpuls-generierten Nanostrukturen auf Metallen (Stahl, Titan). Besonderes Augenmerk wird dabei auf die Rolle der laserinduzierten Oxidschicht im Zusammenspiel mit verschleißreduzierenden Additiven in ölbasierten Schmiermitteln gerichtet. T2 - Internationale Bodensee Fachtagung „Wärmebehandlung und Oberflächentechnik zur Verbesserung von Tribologie und Verschleissbeständigkeit" CY - Feldkirch, Austria DA - 20.03.2025 KW - Additive KW - Laser-induzierte periodische Nanostrukturen KW - Reibungsreduktion KW - Verschleißreduktion PY - 2025 AN - OPUS4-62757 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Generation and characterization of anisotropic nanostructures using ultrashort pulsed lasers N2 - The lecture gives an overview of the generation and characterization of anisotropic nanostructures using ultrashort pulsed laser radiation. Special attention will be paid to the phenomenon of so-called laser-induced periodic surface structures (LIPSS) on various materials. One focus will be on dielectrics and the dynamics of nanostructure formation. Further examples of bulk nanostructures from the literature will be discussed. T2 - 8th UKP-Workshop: Ultrafast Laser Technology CY - Aachen, Germany DA - 08.04.2025 KW - Laser-induced Periodic Surface Structures (LIPSS) KW - Dielectrics KW - Surface Nanostructures KW - Volume Nanostructures PY - 2025 AN - OPUS4-62947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - Entwicklungen zu Bestimmungsverfahren für sicherheitstechnische Kenngrößen des Explosionsschutzes für hybride Gemische N2 - Zur Bestimmung sicherheitstechnischer Kenngrößen (STK) von hybriden Gemischen (Gemisch aus mindestens zwei brennbaren Phasen, wie z.B. Staub/Gas- oder Gas/Dampf-Gemisch) existieren bislang keine einheitlichen, genormten Prüfmethoden. Die Normen und Regelwerke zur Bestimmung der STK von einphasigen brennbaren Systemen (Staub, Gas, Dampf) unterscheiden sich teilweise erheblich. Beispielsweise sind in den jeweiligen Normen für Stäube, Gase und Dämpfe unterschiedliche Zündquellen und Zündenergien definiert. Des Weiteren unterscheiden sich die in den Normen definierten Prüfabläufe bei der Gemischherstellung. Bei der Entwicklung einer einheitlichen Norm für hybride Gemische muss der Einfluss dieser beiden Parameter ermittelt werden, um die Vergleichbarkeit mit den STK der einzelnen Komponenten Gas, Staub und Dampf gewährleisten zu können und bisherige Erkenntnisse zu hybriden Gemischen interpretieren und bewerten zu können. T2 - VDI-Fachtagung "Sichere Handhabung brennbarer Stäube" CY - Online meeting DA - 04.11.2020 KW - Hybride Gemische KW - Explodierender Draht KW - Sicherheitstechnische Kenngrößen KW - Zündquellen PY - 2020 AN - OPUS4-51692 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lucaßen, J. T1 - Bottom-up grown CISe micro absorber arrays: microstructure analysis and solar cell integration N2 - A reduction of critical raw materials like indium and gallium in chalcopyrite thin-film solar cells is aimed for the micro-concentrator concept. Bottom-up grown micro absorbers for operation under light concentration on the micrometer scale allow improved heat dissipation. T2 - 41st European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2024) CY - Vienna, Austria DA - 23.09.2024 KW - Laser-assisted MO-CVD KW - CISe micro-absorber KW - Micro solar cell arrays KW - Solar cell efficiency PY - 2024 AN - OPUS4-62075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Ultrafast optical probing of laser-induced formation of periodic surface nanostructures N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a coherent laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. The presentation provides an overview of current theories on LIPSS and the quest to achieve ever smaller surface nanostructures. The historical development of the fundamental ideas behind LIPSS is presented, together with experimental approaches that make it possible to distinguish between the various LIPSS formation scenarios. Time-resolved experimental methods are required to investigate the dynamics of their formation. The presentation focuses on ultrafast time-resolved optical (pump-probe) techniques that can be used for localized point measurements or microscopic imaging, utilizing the reflection, diffraction, or coherent scattering of the probe radiation at the emerging LIPSS, while simultaneously capturing information about rapid melting, ablation, and solidification phenomena. However, given the sub-micrometric spatial periods of LIPSS, their analysis using optical radiation employed in far-field techniques remained a challenge. Therefore, short wavelengths of the probe beam in the UV range or even below are required to overcome the diffraction limit imposed in the optical spectral range. Fourth-generation light sources, namely short-wavelength (XUV or X-ray) short-pulse free-electron lasers (FELs), offer new and fascinating possibilities for resolving laser-induced structure formation on surfaces in the sub-micrometer to nanometer range and in time domains from picoseconds to several nanoseconds with a resolution in the sub-picosecond regime. On laser-irradiated semiconductor surfaces, this unique spatio-temporal resolution enables the detection of early signs of coherent/plasmonic electromagnetic scattering effects, followed by the excitation of hydrodynamic capillary waves – providing new insights into the above-mentioned debate. Recent experiments at the European XFEL used fs-time-resolved small-angle X-ray scattering (fs-SAXS) and even fs-time-resolved grazing incidence small-angle X-ray scattering (fs-GISAXS), combined with grazing-incidence diffraction (fs-GID), to reveal the dynamics of the formation of nanometric LIPSS on metals. T2 - CINSaT Herbstkolloquium 2025 CY - Kassel, Germany DA - 05.11.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses KW - Pump-probe measurements KW - Free-electron laser KW - Small angle X-ray scattering (SAXS) PY - 2025 AN - OPUS4-64633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hassenstein, Christian T1 - Robotergestützte Ultraschallprüfung von Objekten mit komplexen Geometrien N2 - Durch den Einsatz moderner digitaler Design- und Fertigungsmethoden wachsen einerseits die Komplexität von Bauteilen, andererseits der Bedarf an Informationen über deren Qualität und Zustand. Damit steigen auch die Anforderungen an die zerstörungsfreie Prüfung, die im Zuge von ZfP 4.0 automatisierte und flexible, innovative Prüfmethoden erfordert. Das gilt insbesondere für Objekte, deren Oberflächengeometrien über plane Flächen und eindimensionale Krümmungen hinausgehen. Um zu zeigen, wie eine Ultraschallprüfung von Objekten mit komplexer Oberflächengeometrie realisiert werden kann, wurde an der BAM eine roboterbasierte Demonstratoranlage entwickelt. Dabei führt ein Roboterarm einen Array-Prüfkopf in Tauchtechnik senkrecht über die Prüffläche. Die dafür erforderliche Prüfbahn kann entweder anhand der CAD-Geometrie oder mithilfe einer Punktewolke der Prüffläche, die vorab mit einem am Roboter angebrachten Laser-Profilometer erfasst wird, ermittelt werden. Zur Erhöhung der Genauigkeit werden der Lasersensor und der Ultraschallprüfkopf automatisiert mit dafür entwickelten Routinen am Roboter eingemessen. Durch bildgebende Verfahren und eine automatische Auswertung der Bilder kann die in Tauchtechnik auftretende Brechung des Schallbündels an der Prüfteiloberfläche berücksichtigt werden, was die ortsrichtige Rekonstruktion von Anzeigen aus dem Prüfteilinneren bzw. der Rückwand ermöglicht. Durch Rückführung der Anzeigen in ein gemeinsames Koordinatensystem entsteht eine 3D-Rekonstruktion des Prüfteils. Der vorliegende Beitrag stellt die Demonstratoranlage und die angewendeten Methoden im Detail vor und nennt Anwendungsbeispiele. T2 - DGZfP Jahrestagung 2025 CY - Berlin, Germany DA - 26.05.2025 KW - Ultraschall KW - Robotik KW - Turbinenschaufel KW - Wanddicke KW - Defekterkennung PY - 2025 AN - OPUS4-63417 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voss, Heike T1 - ReguΛarity - A free software for the objective quantification of the regularity of periodic surface structures generated by femtosecond laser irradiation N2 - The precise laser-based surface structuring on the micro- and nanoscale allows to create functional properties for innovative applications, e.g., in medicine, optics and biology. Among the various types of surface structures, laser-induced periodic surface structures (LIPSS) are characterized by their versatility and the relatively simple manufacturing process. However, the fabrication of highly regular LIPSS patterns remains challenging. The systematic investigation of LIPSS formation, as well as of the resulting functional properties requires a precise evaluation of the surface morphology, especially with regard to periodicity and regularity. Existing quantification methods such as Fast Fourier Transformation (FFT) tend to lack automation and objectivity, especially when dealing with large data sets and multi-scale structures. Although automated approaches exist with the Gini coefficient and the P³S method, their limited availability restricts a broader scientific use. We therefore introduce ReguΛarity as an innovative open-source software solution for objective, rapid and reproducible evaluation of structured surfaces concerning their regularity. In order to provide comprehensive surface morphological analysis, our software uses advanced image-processing techniques and integrates the already developed tools such as P³S method, Gini coefficient, FFT analysis, and the calculation of DLOA (Dispersion of LIPSS Orientation Angle). The software allows to evaluate any relevant image format as provided, e.g., by standard scanning electron micrographs. An intuitive PyQt5-based interface, enhanced by multi-threading capabilities, facilitates efficient data processing. Interactive features such as region-of-interest selection and plotting provide flexible adaptation to diverse applications. ReguΛarity offers a robust analysis tool that will contribute to the further development of precise laser-based surface structuring and to the optimization of the desired functional properties in both research and industry. T2 - 13th International Conference on Photoexcited Processes and Applications, ICPEPA-13 CY - Lecce, Italy DA - 14.09.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Laser processing KW - Fourier transformation KW - Regularity PY - 2025 AN - OPUS4-64176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rahner, E. T1 - From nightmare to numbers - A novel software tool for objective regularity analysis of LIPSS N2 - The precise laser-based surface structuring on the micro- and nanoscale allows for the creation of functional properties for innovative applications, e.g., in medicine, optics and biology. Among the various types of surface structures, laser-induced periodic surface structures (LIPSS) are distinguished by their versatility and the comparatively simple manufacturing process. Nevertheless, the fabrication of highly regular LIPSS patterns remains challenging. The systematic investigation of LIPSS formation, as well as of the resulting functional properties demands accurate and objective evaluation of surface morphology, especially regarding periodicity and regularity. Existing quantification methods such as Fast Fourier Transformation (FFT) tend to lack automation and objectivity, especially when dealing with large data sets and multi-scale structures. Although automated approaches, such as those based on the Gini coefficient or the P³S method, have been proposed, their limited availability hinders a broader scientific use. To overcome these limitations, we introduce ReguΛarity, a novel, freely available Python-based software tool featuring a graphical user interface for automated and quantitative assessment of regularity in period and (quasi-)periodic surface patterns including LIPSS. The software processes microscopic images obtained from optical, scanning electron microscopy (SEM), or atomic force microscopy (AFM), combining image segmentation with one- and two-dimensional Fourier analyses (1D-FT, 2D-FT), phase evaluation, and gradient-based orientation determination to facilitate a comprehensive regularity analysis of (quasi-)periodic surface patterns with spatial periods Λ. Regularity is quantified by the newly proposed five-dimensional regularity tuple R comprising the normalized spread of spatial periods from 2D-FT, the normalized local variation of the dominant spatial period from 1D-FT, the Gini coefficient G, the Dispersion of the LIPSS Orientation Angle (DLOA), and the mean phase deviation. The demonstration of the software’s capabilities is achieved by comparing idealized sinusoidal test patterns with SEM micrographs of fs-laser-generated LIPSS on stainless steel (AISI 316L) and aluminum alloy (AlMg5). This comparison highlights ReguΛarity’s objective differentiation between varying levels of structural regularity. The software facilitates high-throughput analysis and data-driven optimization in laser surface engineering processes. T2 - 13th International LIPSS Workshop CY - Enschede, Netherlands DA - 29.10.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Fourier transform KW - Gini coefficient PY - 2025 AN - OPUS4-65047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gräf, S. T1 - Ion marker implantation as key to understand the formation of femtosecond LIPSS on steel N2 - Ultrashort laser (fs-laser) pulses can be used to generate laser-induced periodic surface structures (LIPSS, ripples) on different types of materials. A variety of potential applications of these grating-like LIPSS have already been demonstrated in the field of surface functionalization. Examples include structural colours (e.g. for optical effects or safety features), beneficial friction and wear reduction, modification of the wetting behaviour of surfaces, and antibacterial or cell adhesion promoting properties for medical implants. Despite decades of research, however, some aspects regarding the formation mechanism are still unclear and the subject of controversial debate. This involves the two main models of coherent electromagnetic scattering and matter reorganization, which are used for explaining aspects of LIPSS formation and phenomenology. One major issue is to quantify the actual amount of material removal during the fs-laser processing due to the lack of an independent depth reference and to visualize the so-called heat-affected zone accompanying intense fs-laser irradiation. In the present study, near-surface implantation of Mn and N ions into different material depth of Mn-free austenitic stainless steel alloy FeCrNiMo18-12-2 was used to create reference layers of a defined thickness containing the respective elements. LIPSS (type low-spatial frequency LIPSS, LSFL) were fabricated on the polished substrate surfaces in an air environment by fs-laser irradiation (λ = 1025 nm, τ = 300 fs, frep = 100 kHz, F = 1.5 J/cm2). The implanted layers subsequently served as a kind of coordinate system to assess the material removal during the formation process via cross-sectional Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectroscopy (EDXS). Using both analysis methods enabled in particular to determine the position of peaks and valleys of the LIPSS topography in relation to the initial surface before fs-laser irradiation. This confirmed the selective ablation in the LIPSS valleys. Moreover, linking changes in the material’s microstructure, e.g., the crystallinity and near surface elemental composition before and after fs-laser treatment, gave additional insights regarding the transient cooling rates, as recently shown for NiTi alloys. T2 - 13th International LIPSS Workshop CY - Enschede, Netherlands DA - 29.10.2015 KW - Energy dispersive X-ray analysis (EDX) KW - Ion implantation KW - Laser-induced periodic surface structures (LIPSS) KW - Steel KW - Transmission electron microscopy (TEM) PY - 2025 AN - OPUS4-64900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Bacterial adhesion on ultrashort pulse laser processed surfaces ― more than size matters! N2 - Bacterial biofilms are aggregates of bacterial cells, often attached to a surface, and enclosed by a self-produced extracellular matrix which confers increased stress tolerance and resistance to cleaning. Biofilm formation leads to biofouling which gives rise to high costs in numerous technical settings due to biocorrosion and biodegradation. However, biofilms can also be attractive for industrial settings such as wastewater treatment systems or for soil bioremediation processes. Hence, the control of bacterial adhesion to a surface is of major concern. Surface topography strongly influences bacterial adhesion. Therefore, one promising way to achieve bacteria-guiding surfaces lies in the contactless and aseptic large-area laser processing of technical surfaces. We used short and ultrashort pulsed laser systems to generate different surface textures, mainly high-spatial-frequency and low-spatial-frequency laser-induced periodic surface structures, LIPSS (HFSL and LFSL), on Ti, Ti-alloy, steel, and polymers (PET and PE). Pristine (polished) and laser processed samples were subjected to bacterial adhesion experiments with two different Escherichia coli strains and Staphylococcus aureus as test organisms. The bacterial strains differed in their cell wall structure (grampositive vs. gramnegative strains), in size, shape, the occurrence of cell appendages, and in their biofilm forming capabilities. Adhesion patterns were analyzed microscopically and compared regarding the respective test strain and surface topography. Our results revealed that adhesion behavior strongly depends not only on the material’s topography and chemistry, but also on the specific bacterial strain, the presence of cell appendages, and ambient growth conditions. T2 - 13th International LIPSS Workshop CY - Enschede, Netherlands DA - 29.10.2025 KW - Bacterial adhesion KW - Biofilm KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses PY - 2025 AN - OPUS4-64632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voss, Heike T1 - Morphology and regularity of high-spatial frequency laser-induced periodic surface structures (HSFL) on titanium materials N2 - Titanium and its alloys are known to enable the straightforward laser‐based manufacturing of ordered surface nanostructures, so‐called high-spatial frequency laser‐induced periodic surface structures (HSFL). These structures exhibit sub‐100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, HSFL were processed on different titanium materials (bulk, film) upon irradiation with near‐infrared ps‐laser pulses (1030 nm wavelength, ≈1 ps pulse duration) under different laser scan processing conditions in normal air atmosphere. Here, we extend our previous work on chemical analyses of HSFL on titanium materials towards a more detailed large-area morphological and topographical surface characterization. For this purpose, scanning electron or atomic force microscopic images are subjected to a regularity analysis using our ReguΛarity software. The results are assessed with respect to the influences of sample- or laser-related parameters on the regularity of the HSFL. T2 - 13th International Conference on Photoexcited Processes and Applications, ICPEPA-13 CY - Lecce, Italy DA - 14.09.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Laser processing KW - Ulltrashort laser pulses KW - Titanium PY - 2025 AN - OPUS4-64173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gräf, S. T1 - Ion marker implantation for tracing the formation of femtosecond LIPSS on steel N2 - An ion marker experiment is conducted to investigate the formation of low spatial frequency laser-induced periodic surface structures (LIPSS) on stainless steel surfaces upon scan-processing with femtosecond laser pulses (300 fs, 1025 nm, 100 kHz) focussed to a spot diameter of ~20 µm. Defined concentration depth profiles of 14N^+- and 55Mn^+-ions were implanted below the polished surface of a cast Mn- and Si-free stainless steel AISI 316L using an acceleration energy of 380 keV. This generated two distinct “depth-tracer-layers” ~135 nm (55Mn) and ~340 nm (14N) below the sample surface. The sample morphology and microstructure were evaluated before and after LIPSS-processing using scanning and transmission electron microscopy techniques in top-view and cross-sectional geometry. Energy-dispersive X-ray spectroscopy (EDXS) allowed to visualize the depth distribution of the marker elements, the steel constituents, and of oxygen involved through the laser processing in ambient air. These experiments revealed that the LIPSS on this metal are predominantly formed by material removal through locally varying ablation and, to a lesser extent, by local melt displacement effects prior to the re-solidification. Moreover, the processing in air leads to the formation of a less than 10 nm thick laser-induced oxide layer covering the steel surface. Our new tracer ion approach contributes to the ongoing debate on the relevance of electromagnetic or hydrodynamic effects during the formation of LIPSS. T2 - E-MRS Spring Meeting 2025 CY - Strasbourg, France DA - 26.05.2026 KW - Laser-induced periodic surface structures (LIPSS) KW - Steel KW - Ion implantation KW - Transmission electron microscopy (TEM) KW - Energy dispersive X-ray analysis (EDX) PY - 2025 AN - OPUS4-63274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grunewald, Thomas T1 - Nichtelektrischer Explosionsschutz: Zündgefahren durch Funken - Grundlagen und Maßnahmen zum Explosionsschutz N2 - Geräte und Maschinen, die zur bestimmungsgemäßen Verwendung in explosionsgefährdeten Bereichen gemäß 2014/34/EU konstruktiv vorgesehen sind, muss in der europäischen Union eine Zündgefahrenbewertung durchgeführt werden. Dabei müssen alle 13 Zündquellen betrachtet werden. Eine Teilmenge der 13 Zündquellen sind die Gefahren von nichtelektrischen Zündquellen, zu denen auch die mechanischen Schlag-, Schleif- und Reibvorgänge gehören. Bei mechanischen Schlagvorgängen kommt es infolge des Zusammenstoßes zweier Werkstücke bzw. Bauteile zu einer Umwandlung der kinetischen Energie. Dabei erhöht sich die Temperatur der Werkstoffe an der Kontaktstelle und es kommt unter Umständen zu einem Abtrennvorgang kleiner Partikel erhöhter Temperatur. Sowohl die heißen Kontaktstellen (Zündquelle "heiße Oberflächen") als auch die abgetrennten Partikel (Zündquelle "mechanisch erzeugte Funken") können eine wirksame Zündquelle für ein explosionsfähiges Gasgemisch darstellen. Zur Festlegung von Grenzwerten wurden in der Norm DIN EN ISO 80079-36:2016 die Gasgemische anhand ihrer Explosionsgruppe klassifiziert und zu jeder Gruppe die maximale Energie des Schlagvorgangs festgelegt, unter derer die Entstehung einer wirksamen Zündquelle als unwahrscheinlich angenommen werden kann. Weitere Festlegungen von Grenzwerten für die kinetische Schlagenergie und geeignete Werkstoffpaarungen finden sich u.a. in der DIN EN 1755 (ex-geschützte Flurförderzeuge) und in der DIN EN 14986 (ex-geschützte Ventilatoren). T2 - Ausbildung zum Explosionsschutzbeauftragten CY - Essen, Germany DA - 20.01.2026 KW - Schlagfunken KW - Schleiffunken KW - Reibfunken KW - Explosionsschutz KW - Nichtelektrischer Explosionsschutz KW - Mechanischer Explosionsschutz PY - 2026 AN - OPUS4-65398 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ebell, Gino T1 - Spannstahlgefährdung - Stand der aktuellen Erkenntnisse aus Sondierungen und Materialuntersuchungen N2 - Spannstahlbrücken die in der Vergangenheit mir vergüteten Spannstählen errichtet worden sind können unter ungünstigen Gegebenheiten bei deren Erstellung signifikante Probleme hinsichtlich der Tragfähigkeit bekommen. Im Speziellen kann die wasserstoffinduzierte Spannungsrisskorrosion hier bei der Errichtung der Brückenbauwerke Anrisse an den Spanndrähten erzeugt haben die Jahre später zum Versagen der Brücke führen können. Die Präsentation im Speziellen behandelt den Teileinsturz der Carolabrücke in Dresden und neue Erkenntnisse zu vergüteten Spannstählen. T2 - BMV - Workshop CY - Bonn, Germany DA - 20.01.2026 KW - Korrosion KW - Spannstahl KW - Spannungsrisskorrosion KW - Wasserstoff PY - 2026 AN - OPUS4-65403 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koch, Claudia T1 - Ensuring Quality Smarter with a digital Quality Infrastructure (Mexican-German Technical Exchange) N2 - The presentation introduces the initiative QI‑Digital, which aims to holistically transform quality infrastructure across all its elements. To this end, a digital QI ecosystem is being developed that integrates digital QI tools with advanced methods for testing, inspection, and monitoring, and embeds them into the broader digital industrial ecosystem. Sovereign and secure data sharing and management are enabled through technologies such as data spaces, the Asset Administration Shell, verifiable credentials, and the Digital Product Passport (DPP). Particular emphasis is placed on the role of artificial intelligence in quality assurance: Several use cases and ongoing projects from BAM are presented togetehr with the business benefits they enable. Ongoing activities on the use of AI for manageing quality-related documentation are also presentated that aim at establishing an agentic AI framework for QI. The talk concludes with key lessons learned so far within the initiative. T2 - Mexican-German Technical Exchange on QI Digital CY - Mexico City, Mexico DA - 23.01.2026 KW - Quality infrastructure KW - Agentic AI KW - Digital Ecosystem PY - 2025 AN - OPUS4-65411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn A1 - Fellinger, Tim-Patrick T1 - Berlin Battery Lab - Vom Material zur Zelle - Batterieinnovation aus Berlin N2 - Das Berlin Battery Lab (BBL) vereint exzellente Materialforschung, modernste Analytik und gezielten Technologietransfer. Als gemeinsames Labor von BAM, HZB und der Humboldt Universität zu Berlin entwickeln wir zukunftsfähige Natrium-Ionen- und Metall-Schwefel-Batterien – von der Materialidee bis zur funktionsfähigen Zelle. T2 - Batteriaforum Deutschland CY - Berlin, Germany DA - 20.01.2026 KW - Batterie KW - Kooperation KW - Natrium-Ionen KW - BBL PY - 2026 AN - OPUS4-65410 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ruehle, Bastian T1 - MINERVA-OS: The Orchestrator of our SDL for Nano and Advanced Materials Synthesis N2 - We present our SDL "Minerva" and its' Orchestrator "Minerva-OS". We discuss the general architecture of the orchestrator, the problems our orchestration solution solves, associated objectives, and success criteria. We demonstrate how a user would interact with it and give examples of what it has already been used for. We also provide some explanation of the available and planned features, and how workflows/experiments are represented. Lastly, we discuss key technical challenges we faced during development. T2 - Orchestration Alignment Virtual Workshop CY - Online meeting DA - 20.01.2026 KW - Self Driving Labs KW - Materials Acceleration Platforms KW - Workflows KW - Orchestration PY - 2026 AN - OPUS4-65422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Absorption and Refraction Techniques: Characterization and Non-Destructive Testing of Additively Manufactured Materials N2 - The combination of tomographic, microstructural data with other experimental techniques and with modeling is paramount, if we want to extract the maximum amount of information on material and component properties. In particular, quantitative image analysis, statistical approaches, direct discretization of tomographic reconstructions represent concrete possibilities to extend the power of the tomographic 3D representation to insights into the material and component performance. This logic thread equally holds for industrial and academic research, and valorizes expensive experiments such as those carried out at synchrotron sources, which cannot be daily repeated. I will show a few examples of possible use of X-ray tomographic data for quantitative assessment of damage evolution and microstructural properties, as well as for non-destructive testing. Examples of micro-structured inhomogeneous materials will be given, such as Composites, Ceramics, Concrete, and Additively manufactured parts. I will also show how X-ray refraction computed tomography (CT) can be highly complementary to classic absorption CT, being sensitive to internal interfaces. Additionally, I will present a new technique in our portfolio, Neutron Diffraction, which is extremely well suited to the study of internal stresses, both residual and under external load. T2 - Kolloquium an dem ‘Laboratoire National de Metrologie et d’Essais CY - LNE’ Paris, France DA - 09.06.2016 KW - Computertomographie KW - Metrologie KW - 3D Mikrostruktur KW - Zerstörungsfreie Prüfung KW - Röntgenrefraktion KW - Additive Fertigung KW - TF Material KW - Analytical Science PY - 2016 AN - OPUS4-38826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maiwald, Michael T1 - Erfahrungsaustausch Labor-Robotik N2 - Die BAM setzt in ihren analytischen Labors zunehmend Labor-Robotik ein, um gefähliche oder zeitraubende Routineaufgaben zu automatisieren. Durch Automation kann auch die Reproduzierbarkeit solcher Anwendungen erhöht werden. Im Beitrag werden einige aktuelle Beispiele aus den Analytiklabors diskutiert, wie z. B. die Anwendung für die Herstellung und RFA-Analytik von Gläsern, eine Feinwäge-Robotik für 10-L-Gaszylinder im Rahmen der Herstellung von Primärnormalen oder die Automatisierung von Probenpräsentationen für optische Spektroskopie und chemical Imaging. Auch wird kurz auf den Einsatz von Speicherprogrammierbaren Steuerungen in der modularen Laborautomation und die Virtualisierung von analytischen Laborrechnern eingengangen. T2 - Industrienetzwerk Smartes Labor am Institut für Energie- und Umwelttechnik e.V. (IUTA) CY - Duisburg, Germany DA - 09.11.2022 KW - Laborautomation KW - Labor-Robotik KW - Automatisierung KW - Smartes Labor PY - 2022 AN - OPUS4-56227 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Höhne, Patrick T1 - Small batch preparation of ready-to-press powder for systematic studies N2 - Efficient studies of scarce or expensive materials require material saving processes. Therefore, a high yield concept for small batch preparation of ready-to-press powder is exemplarily presented for yttria stabilized nano-zirconia (d50 < 50 nm). The concept involves small batch preparation in an ultrasound resonator, dispersant selection based on zeta potential measurements, evaluation of slurry stability using an analytical centrifuge, and preparation of ready-to-press powder by freeze drying. Freeze drying offers key advantages. Process efficiency and high yield above 95 % are independent of sample size. The dried product does not require further mechanical treatment like milling or grinding. Side effects like migration of additives are avoided. An optimized freeze drying process tolerates slurries with moderate stability. Thus, efforts for slurry development can be reduced. Generally, identifying a suitable dispersing agent requires only 3-5 zeta potential measurements. Slurry stability is rechecked using an analytical centrifuge, which also accounts for steric stabilization. An ultrasound resonator is used to disperse the powder without contamination, which becomes critical for small batches. The described route is exemplarily presented for the development of an additive recipe for nano-sized zirconia powder, targeting for good pressing behavior and high green density. Therefore, a variety of binding and lubricating agents were tested. Following the presented route, 80 g zirconia powder were sufficient to conduct a study including slurry development and five sample sets with varying composition, each set comprising five discs (d = 20 mm and h = 2 mm). T2 - 94. DKG Jahrestagung CY - Leoben, Austria DA - 05.05.2019 KW - Fine Powder KW - Slurry KW - Freeze Drying PY - 2019 AN - OPUS4-48293 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - You, Yi T1 - Acoustic Ion Manipulation (AIM) N2 - The precise control of gaseous ions is a cornerstone in ion-based spectrometry and other disciplines such as materials processing. Traditional high-pressure ion optics rely on electrostatic and magnetic fields that often demand the use of intense electric fields, radio frequency activation, complex geometrical arrangements, or partially transmissive grids. Consequently, the efficiencies of such devices tend to be low or they require large footprints, as ion motions under ambient conditions are governed aerodynamically by collisions and fluid dynamics. However, from a different perspective and holistic reasoning, the limitations posed by collisions, aerodynamics, and other factors that hinder ion control in the open-air suggested an innovative direction for ion manipulation. Our study introduces a novel method that employs low-power standing acoustic waves to effectively manipulate ion beams. We observe that ions distinctively prefer traveling through areas of static pressure within the acoustic field, identified as "nodes." In contrast, neutral gases are unaffected by the acoustic field structure and continue to move along a straight trajectory. We have named this method Acoustic Ion Manipulation (AIM). Initial studies demonstrated selective and efficient manipulations of ion with AIM, including gating, redirection, regional dispersion, and focusing. This technique broadens the scope of ion manipulation strategies at high pressures while enriching our fundamental understanding of ion-acoustic kinetics. The potential applications of this method are vast, promising significant advancements in the fields of analytical chemistry, environmental science, and beyond. T2 - ANAKON 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - Acoustic ion manipulation KW - Mass spectrometry PY - 2025 AN - OPUS4-64110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Li, Xunyu T1 - Atomic Isotope Analysis of Lithium with Spatial Heterodyne Spectrometry and Lineshape Recovery through Deconvolution N2 - A spatial heterodyne spectrometer (SHS) was combined with a reduced-pressure glow discharge to demonstrate the analytical utilization of high resolving-power spectral analysis for atomic isotopes. In the experimental illustrations, we will demonstrate the spectra for the lithium isotope ratio through the D-lines featuring 6Li and 7Li. The SHS utilized in our setup boasts single-digit picometer resolution, enabling the precise discrimination of three separate spectral bands in real-time. To further enhance the spectral quality and improve quantification accuracy, we established an innovative approach to recover the natural lineshape, avoiding interferences from the instrumental function that broadens fine features. By understanding the inherent characteristics of an SHS interferogram and leveraging computational capabilities, we will demonstrate the direct extraction of the numerical presentation of the instrumental function from an SHS interferogram; this instrumental function was used for spectral data processing that enables significant improvements in spectral resolution through deconvolution algorithms. The resulting high-quality spectra enabled precise quantitative determination of lithium concentrations and isotope ratios. We aim to showcase the procedures involved in fine-tuning an SHS platform, along with software design strategy to track real-time spectral variations. Meanwhile, the concept of the lineshape recovery through deconvolution will also be discussed. Furthermore, atomic lithium spectra featuring various isotope compositions will be presented to highlight the potential of SHS in real-life applications. T2 - SCIX 2024 Conference CY - Raleigh, NC, USA DA - 20.10.2024 KW - Spatial Heterodyne Spectrometry KW - High-Resolution Spectrometry KW - Isotopic Analysis KW - Line Shape Recovery KW - Instrumental Function PY - 2024 AN - OPUS4-62138 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Magkos, Sotirios T1 - The DIRECTT algorithm: A promising alternative for Computed Tomography reconstructions N2 - The DIRECTT (Direct Iterative REconstruction of Computed Tomography Trajectories) algorithm represents a promising alternative to conventional algorithms, such as the Filtered Backprojection (FBP) or the Algebraic Reconstruction Technique (ART), by overcoming restrictions associated with them. Such restrictions include the limited spatial resolution achieved through FBP due to Nyquist‘s sampling theorem, the inability of FBP to perform a quality reconstruction when projections are missing, and the excessive computing time needed for ART. T2 - CINEMAX IV Summer School CY - Toreby, Danmark DA - 27.08.2018 KW - Computed tomography KW - Reconstruction algorithm KW - Spatial resolution PY - 2018 AN - OPUS4-46448 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hufgard, Josefin T1 - Use Your Time (Domain) Wisely: Streamlined Analysis of Complex Mixtures with Pulsed-Laser Techniques N2 - This study aims to streamline complex mixture analysis through the parallel ionization of all analytes without extensive preprocessing. Here, pulsed laser ablation of single droplets is used with modified cross-correlation, a phase-sensitive algorithm. This combined method allows contactless chemical investigation with minimal sample pretreatment, as well as the separation of analytes in mixtures and reconstruction of analyte-specific mass spectra. T2 - Future WINS: Corss-sections and interfaces in science, careers, and communication CY - Berlin, Germany DA - 21.11.2024 KW - MS KW - Data analysis KW - Laser ablation PY - 2024 AN - OPUS4-62124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Was kann die Neutronenbeugung für die ZfP tun? N2 - Neutronenbeugung hat verschiedenste Anwendungen, die auf die eigenartigen physikalischen Eigenschaften der Neutronen berühen. Während die Beugungstechniken wie z.B. die klassische Pulverbeugung, die Kleinwinkelstreuung und die Texturanalyse besonders für die Materialcharakterisierung nutzbar sind, setzt sich die Neutronenbeugung als zerstörungsfreies Verfahren für Eigenspannungsanalyse extrem relevant ein. Allerdings sind nur wenig die Leute, die die Neutronenbeugung in der ZfP Community benutzen. Dieser Vortrag hat das Ziel die Interesse an der Nutzung von einem solchen Grossgerätwerkzeug aufzuwecken und ein Paar impactvolle Anwendungsbeispiele einiger Techniken zu zeigen. Die Bestimmung mikroskopischer mechanischen Eigenschaften von Kompositen (MMC oder CMC), sowie der Mapping von Eigenspannungsfelder in Komponenten werden bearbeitet. Es wird gezeigt, dass Neutronenbeugung grundsätzlich eine zerstörungsfreie Methode für beide die Materialcharakterisierung und die Komponentenintegrität ist, die hohes Potentiell hat, zum Verfahrensportfolio der zerstörungsfreier Prüfung zu gehören. T2 - 381. Sitzung des Arbeitskreises Berlin der DGZfP CY - BAM, Berlin, Deutschland DA - 01.11.2016 KW - Neutronenbeugung KW - Eigenspannungen KW - Kompositen KW - Legierungen KW - Schweißnähte KW - TF Material PY - 2016 AN - OPUS4-38313 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shashev, Yury T1 - Talbot- Lau interferometry with a non- binary phase grating for non-destructive testing N2 - Grating interferometric set-ups have been established in the last decade. They are promising candidates to obtain enhanced image contrast from weakly absorbing micro and nano structures. They are based on X-ray refraction and near-field diffraction using the Talbot effect. At the expense of taking multiple images, Talbot-Lau grating interferometry allows separating the absorption, refraction, and scattering contributions by analysing the disturbances of a phase grating interference pattern. Contrary to other refraction enhanced methods, this technique can be applied using conventional X-ray tubes (divergent, polychromatic source). This makes it attractive to solve typical non-destructive testing problems. We investigated the efficiency of phase gratings, i.e. the visibility (the amplitude of oscillations) upon variation of propagation distance and phase grating rotation around an axis parallel to the grid lines. This grating rotation changes the grating shape (i.e. the distributions of phase shifts). This can yield higher visibilities than derived from rectangular shapes. Our study includes experimental results obtained from synchrotron radiation, as well as simulations for monochromatic radiation. The advantages of Talbot-Lau interferometry are demonstrated at the example of glass capillaries. T2 - WCNDT 2016 CY - Munich, Germany DA - 13.06.2016 KW - Phase grating KW - X-ray phase contrast imaging KW - Talbot- Lau interferomerty KW - Visibility KW - Synchrotron PY - 2016 AN - OPUS4-36625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pelkner, Matthias T1 - Evaluation of high spatial resolution imaging of magnetic stray fields for early damage detection N2 - Metal magnetic memory (MMM) technique with associated ISO 24497-1:3 is gaining considerable interest in the magnetic NDT community. In contrast to traditional Magnetic Flux Leakage (MFL) testing, the inspection objects are not intentionally magnetized by an external magnetic field. Due to the physical coupling between mechanical stress and magnetization of ferromagnetic materials, it is assumed that the distribution of the residual MFL correspond to the internal stress of the specimen, or in the most general sense, to a degradation of the material. Usually, MMM measurements are performed by relatively bulky magnetic inspection sensors. The evaluation of local magnetic field distribution is limited thereby. Highprecision GMR (Giant Magneto Resistance) measurements in the micrometer regime can provide a higher degree of information due to better spatial resolution. We present a concise summary of studies on the correlation of magnetic structure and microstructure of steels. In particular, we compare residual stress measurements in S235JRC steel welds by means of neutron diffraction with high resolution magnetic field mappings. Results indicate a qualitative correlation between residual stresses and local stray field variation. In addition, stray field measurements of plastically deformed specimens for quasi-static and cyclic loading cases are discussed. The present study concludes that GMR sensors can detect inhomogeneous plastic deformations of S235JR steel in a very early stage, without specific signal processing according to the ISO 24497-1:3. T2 - QNDE - Review of Progress in Quantitative Nondestructive Evaluation CY - Atlanta, Georgia, USA DA - 18.07.2016 KW - NDT KW - MMM KW - GMR PY - 2016 AN - OPUS4-37101 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. T1 - Hochauflösende, schnelle Materialcharakterisierung - Zerstörungsfeie Prüfung mittels Röntgenrefraktion N2 - Materialcharakterisierung von CFK-Werkstoffen mittels Röntgen-Refraktion T2 - CCeV-Veranstaltung 3er-AG CY - Augsburg DA - 04.03.2016 KW - CFK KW - Röntgen-Refraktion KW - Faser-Matrix Enthaftung PY - 2016 AN - OPUS4-35666 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Pressure assisted sintering of tape cast calcium cobaltite N2 - Thermoelectric materials can convert waste heat directly into electrical power by utilizing the Seebeck effect. Calcium cobaltite Ca3Co4O9 is a promising p-type oxide thermoelectric material for applications between 600 °C and 900 °C in air. The properties and morphology of Ca3Co4O9 are strongly anisotropic because of its crystal structure of alternating layers of CoO2 and Ca2CoO3. The electrical conductivity is for example 13.5 times higher in a/b-direction than in c-direction. By aligning the plate-like grains, the anisotropic properties can be assigned to the component. Hot-pressing of tablets is a well-known technology for grain alignment of Ca3Co4O9 and increases the thermoelectric properties in a/b-direction remarkably. It also increases the relative density. However, hot-pressing of tablets is limited by the tablet size. An interesting alternative for larger components is the pressure assisted sintering of panels from tape casted layers. Tape casting already leads to a grain alignment during green body forming. By combining tape casting and pressure assisted sintering (50 kN maximum force) of Ca3Co4O9, high densities and high thermoelectric properties can be reached for large components up to 200 mm edge length. Ca3Co4O9 was successfully tape casted with the doctor blade technique (binder: polyvinyl butyral, organic solvent). Several layers of tape were stacked and laminated to 5 cm x 5 cm panels. These panels were sintered with different applied pressures in a LTCC sintering press with combined in-situ shrinkage measurement. Pressure-less sintered panels have a 2.5 times higher electrical conductivity at room temperature than test bars with randomly orientated particles. By applying a uniaxial pressure of 10 MPa during sintering, the electrical conductivity increases by the factor of 6 compared to the pressure-less sintered panels. About 40 % linear shrinkage are reached in pressing direction. The Seebeck coefficient (S25 °C=146 μV/K) and the electrical conductivity (σ25 °C=15100 S/m) are in good agreement with the values published in literature for hot-pressed tablets. T2 - 15th Conference & Exhibition of the European Ceramic Society CY - Budapest, Hungary DA - 09.07.2017 KW - Thermoelectrics KW - Pressure assisted sintering PY - 2017 AN - OPUS4-41026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -