TY - THES A1 - Schilling, Markus T1 - Environmental Stress Cracking (ESC) and Slow Crack Growth (SCG) of PE-HD induced by external fluids N2 - High-density polyethylene (PE-HD) is widely used as a packaging material. Typical applications are pipes and containers for storage and transport of dangerous goods. For these applications, the understanding of the craze-crack damage mechanisms slow crack growth (SCG) and environmental stress cracking (ESC) is of importance. Since these mechanisms are considered to be the major causes of failure, their understanding is essential for inspection and release of those materials. A well-established test method for the assessment of these damage mechanisms is the full-notch creep test (FNCT). It is used in this study for a detailed investigation of crack propagation phenomena in PE-HD container materials under the influence of different fluids such as air, water and aqueous detergent solutions (Arkopal N 100) as well as biodiesel and diesel. Based on the results of the FNCT, a classification scheme of different fluids is proposed, which allows for an assignment of the respective damage mechanisms. Hereby, it is differentiated between (i) inert, (ii) purely surface-active and (iii) additionally sorptive, bulk-active fluids with respect to SCG. If the test fluid changes the intrinsic properties (at the surface or in the bulk), the damage mechanism is addressed to ESC behavior. In FNCT investigations, stress, temperature and specimen geometry were varied systematically. In addition to the time to failure as common measure for the resistance of a PE-HD type against crack propagation, specimen elongation was considered in detail. Several imaging techniques were applied for fracture surface analysis of specimens tested in FNCT to gain novel information on SCG and ESC behavior. From height profiles obtained by laser scanning microscopy (LSM) and information on surface structures from scanning electron microscopy (SEM), indicators for the differentiation of the crack propagation mechanisms could be derived. Based on the LSM data, an algorithm for the distinction between ductile shear deformation and brittle crack growth as dominating failure mechanism was developed. Imaging techniques were also used for determination of crack propagation rates, which were related to time-resolved FNCT elongation data. From the time-resolved determination of crack lengths of partly damaged FNCT specimens, an increasing length of craze zone with a progressively propagating crack was revealed for the first time. This relation of crack and craze zones was specified by fracture mechanical considerations. N2 - Polyethylen hoher Dichte (PE-HD) wird als Werkstoff für Rohre und Behälter für den Transport und zur Lagerung von Gefahrgütern verwendet. Für die Beurteilung und technische Freigabe dieser Materialien ist das Verständnis der beiden Schädigungsmechanismen „langsames Risswachstum“ (engl.: „slow crack growth“, SCG) und „umgebungsbedingter Spannungsriss“ (engl.: „environmental stress cracking“, ESC) essentiell. Eine etablierte Prüfmethode zur Bewertung dieser Schädigungsmechanismen ist der Full-Notch Creep Test (FNCT), der in dieser Arbeit zur systematischen Untersuchung des Risswachstums in PE-HD Behältermaterialien unter Einwirkung von Luft, Wasser und wässrigen Netzmittellösungen (Arkopal N 100) sowie Biodiesel und Diesel verwendet wird. Aus den Ergebnissen des FNCT wird ein Klassifikationsschema für Fluide vorgeschlagen, welches ebenfalls eine Zuordnung zu den Schädigungsmechanismen erlaubt. Hierbei wird in (i) inerte, (ii) rein oberflächen-aktive und (iii) zusätzliche sorptive, volumen-aktive Fluide hinsichtlich des langsamen Risswachstums (SCG) unterschieden. Wenn ein Fluid lokal die intrinsischen Materialeigenschaften des Polymers verändert, wird der Schädigungsmechanismus dem umgebungsbedingten Spannungsriss (ESC) zugeordnet. Bei den FNCT-Untersuchungen wurden die mechanische Spannung, die Temperatur und die Prüfkörpergeometrie systematisch variiert. Zusätzlich zur Standzeit wurde die Prüfkörperdehnung zeitabhängig erfasst. Aus einer erweiterten Bruchflächenanalyse konnten neuartige Informationen über SCG und ESC erhalten werden. Hierzu wurden verschiedene Bildgebungsverfahren verwendet. Insbesondere wurden mit Laserscanningmikroskopie (LSM) Höhenprofile und mit Rasterelektronenmikroskopie (REM) Oberflächeninformationen zur Charakterisierung der Rissfortschrittsmechanismen erhalten. Auf Basis der LSM wurde unter Zuhilfenahme von Höhenprofildaten ein Algorithmus zur Unterscheidung zwischen duktiler Scherverformung und sprödem Risswachstum als dominierende Schädigungsmechanismen entwickelt. Die aus den bildgebenden Verfahren ermittelten Rissfortschrittsraten konnten mit den Daten der während des FNCT erfassten Dehnung der Prüfkörper in Beziehung gesetzt werden. Weiterhin wurde mithilfe von zeitaufgelösten Risslängendaten erstmals eine direkte Korrelation der Risslänge zu vorgeschädigten, fibrillierten Bereichen (Crazes) im PE-HD Prüfkörper während des FNCT nachgewiesen. Demnach vergrößert sich die Craze-Länge linear mit zunehmender Risslänge. Dieser Zusammenhang zwischen Riss- und Craze-Längen wurde auf mathematisch, bruchmechanischer Grundlage bestätigt. KW - High-density polyethylene (PE-HD) KW - Full-Notch Creep Test (FNCT) KW - Slow crack growth (SCG) KW - Environmental Stress Cracking (ESC) KW - Biodiesel KW - Diesel KW - Crack propagation analysis KW - Fracture Surface Analysis KW - Test Improvement KW - Imaging PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:tuda-tuprints-115443 DO - https://doi.org/10.25534/tuprints-00011544 SP - 1 EP - 212 CY - Darmstadt AN - OPUS4-50941 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghafafian, Carineh T1 - Localized repairs for wind turbine rotor blades N2 - The effect of localized repairs on the structural integrity and thus the lifespan of wind turbine rotor blade shells is examined. T2 - SAMPE Symposium 2020 CY - Kassel, Germany DA - 17.02.2020 KW - GFRP KW - Wind turbine blade shells KW - Scarf joint repairs KW - Sandwich PY - 2020 AN - OPUS4-50480 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stephan-Scherb, Christiane T1 - Applied Crystallography as a tool for a better understanding of Fundamental Questions of high temperature corrosion phenomena N2 - Corrosion Science Meets X-Rays, Neutrons and Electrons. The presentation gives an overview on current research activities applying in-situ X-ray diffraction and spectroscopy for a better understanding of fundamental mechanisms of high temperature corrosion. Additionally the knowledge gain by applying neutron powder diffraction and EBSD analysis is presented. T2 - Joint meeting of german and polish crystallographic association 2020 CY - Wroclaw, Poland DA - 24.02.2020 KW - Corrosion KW - Oxidation KW - In situ KW - Diffraction PY - 2020 AN - OPUS4-50483 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heuser, Lina A1 - Sobek, P. T1 - Sintering of silver-alkali zinc borate glass composites N2 - High conductive silver-glass-metallization-pastes are key components in photovoltaics and advanced microelectronics. However, the underlying mechanisms of liquid phase sintering as silver dissolution, diffusion and reprecipitation are poorly understood so far. In the current work, the influence of different network modifier in alkali-zinc-borate paste-glasses on liquid phase sintering of silver-glass-composites was studied. Therefore, silver-glass-composites containing 30 vol% glass were prepared, using low melting X2O-ZnO-B2O3 glasses with X = Na, Li, and Rb (NZB, LZB, and RZB). Glass transition temperature, viscosity, glass-silver wetting, crystallization and sintering behavior was studied by means of thermal analysis, dilatometry, heating microscopy and microscopy. Similar glass transition temperatures of 450 °C (RZB), 460 °C (LZB) and 465 °C (NZB) were found by means of thermal analysis for glasses under study. Also, all glasses have a similar crystallization onset at about 550 °C, even though exhibiting with a different degree of crystallization. Despite these similarities, however, the sintering behavior, measured in terms of area shrinkage, significantly differs for the composites. This finding indicates a different degree of silver dissolution. Assuming that dissolved silver reduces the viscosity, this effect could explain why glass crystallization starts at lower temperature in the composites. For example, the crystallization peak of LZB at 629 °C measured for pure glass powder compacts was decreased to 586 °C for the composite. Confirmatively, microstructure analyses indicate different degrees of silver dissolution, as e.g. revealed by different amount of silver precipitates within the residual glass phase, and reprecipitation. Best silver dissolution appeared for the RZB glass. Nevertheless, the final densification of RZB was retarded probably due to swelling and crystallization. T2 - XRM Workshop CY - Halle, Germany DA - 03.03.2020 KW - Silver-glass-metallization-paste KW - Sintering KW - Alkali ions PY - 2020 AN - OPUS4-51243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Composite materials - focus polymer matrix composites (PMC) N2 - Lecture about polymer matrix composites as part of the first trainings event GW4SHM, properties, production, basic theory, testing. T2 - 1. Training GW4SHM-Project CY - BAM, Berlin, Germany DA - 23.11.2020 KW - Polymer matrix composites KW - Composite testing KW - NDT PY - 2020 AN - OPUS4-51868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nolze, Gert T1 - Lattice parameter determination with EBSD. Is that possible? N2 - CALM is software for determining the Bravais lattice type and the resulting lattice parameters from a single Kikuchi pattern. It requires the definition of 4 bands and a single bandwidth from which all other band positions as well as bandwidths are derived. For band detection, it uses the Funk transform, which allows detection of twice as many bands as usual. CALM works for any symmetry and requires low-noise patterns of at least 320x240 pixels. The resulting errors are <2% even for such small patterns, assuming good quality. The relative errors are <0.5%. However, this requires a projection centre position best derived from a sample of a cubic phase in CALM. However, this must have been recorded under identical conditions. Hundreds of Kikuchi patterns of phases with different symmetries were examined. T2 - Institutskolloquium Kassel CY - Online meeting DA - 30.10.2020 KW - Phasenidentifikation KW - EBSD KW - Gitterkonstanten PY - 2020 AN - OPUS4-51813 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 - Bayerlein, Bernd T1 - Innovations- Plattform Material Digital N2 - Mit der Initiative MaterialDigital fördert das BMBF seit dem letzten Jahr ein wichtiges Instrument zur Digitalisierung der Materialwissenschaft und Werkstofftechnik in Deutschland. In der ersten Phase dieser Initiative wird seit Juli 2019 die Plattform MaterialDigital von einem Konsortium aufgestellt. Ziel dieser Plattform ist der Aufbau eines virtuellen Materialdatenraums, um zusammen mit allen Interessenten die Systematisierung des Umgangs mit Werkstoffdaten voranzutreiben. In einer zweiten Phase werden akademische F&E-Projekte voraussichtlich Anfang 2021 gefördert. In jedem dieser Projekte wird an einer konkreten Fragestellung das Themenfeld „Digitalisierung der Materialwissenschaft und Werkstofftechnik“ adressiert und multidisziplinär bearbeitet. In einer dritten Phase werden im Rahmen industriegeführter vorwettbewerblicher Verbundprojekte mit der gleichen Zielsetzung gefördert. T2 - Workshop - “Datenmanagement in der Additiven Fertigung” CY - Online meeting DA - 27.10.2020 KW - Digitalisierung KW - Plattform Material Digital KW - Virtueller Materialdatenraum KW - Vernetzung KW - Ontologien PY - 2020 AN - OPUS4-51609 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winkelmann, A. A1 - Nolze, Gert A1 - Cios, G. A1 - Tokarski, T. A1 - Bala, P. A1 - Hourahine, B. A1 - Trager-Cowan, C. T1 - Kikuchi pattern simulations of backscattered and transmitted electrons N2 - We discuss a refined simulation approach which treats Kikuchi diffraction patterns in electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). The model considers the result of two combined mechanisms: (a) the dynamical diffraction of electrons emitted coherently from point sources in a crystal and (b) diffraction effects on incoherent diffuse intensity distributions. Using suitable parameter settings, the refined simulation model allows to reproduce various thickness- and energy-dependent features which are observed in experimental Kikuchi diffraction patterns. Excess-deficiency features are treated by the effect of gradients in the incoherent background intensity. Based on the analytical two-beam approximation to dynamical electron diffraction, a phenomenological model of excess-deficiency features is derived, which can be used for pattern matching applications. The model allows to approximate the effect of the incident beam geometry as a correction signal for template patterns which can be reprojected from pre-calculated reference data. As an application, we find that the accuracy of fitted projection centre coordinates in EBSD and TKDcan be affected by changes in the order of 10−3–10−2 if excess-deficiency features are not considered in the theoreticalmodel underlying a best-fit pattern matching approach. Correspondingly, the absolute accuracy of simulation-based EBSD strain determination can suffer frombiases of a similar order of magnitude if excess-deficiency effects are neglected in the simulation model. KW - Electron diffraction KW - EBSD KW - Kikuchi diffraction KW - Pattern matching PY - 2021 DO - https://doi.org/10.1111/jmi.13051 VL - 284 IS - 2 SP - 157 EP - 184 PB - Wiley Online Library AN - OPUS4-53584 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Charmi, Amir T1 - Mechanical anisotropy of additively manufactured stainless steel 316l: an experimental and numerical study N2 - This work aims for a yield function description of additively manufactured (AM) parts of stainless steel 316L at the continuum-mechanical macro-scale by means of so-called virtual experiments using a crystal plasticity model at meso-scale. T2 - 1st Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing CY - BAM, Berlin DA - 10.12.2020 KW - Anisotropy KW - Crystal plasticity KW - Additive manufacturing PY - 2020 AN - OPUS4-51941 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kalinka, Gerhard T1 - Optische Beobachtungen der Faser-Matrix-Trennung im Pull-out-Versuch N2 - Der Vortrag behandelt Rissentstehung und Ausbreitung an Faser-Matrix-Interfaces, untersucht mit dem optischen Mikroskop. T2 - Composites United, CU-Arbeitsgruppe/n Faser-Matrix-Haftung & Matrices CY - Online meeting DA - 02.12.2021 KW - Faser KW - Matrix KW - Pull-out KW - Interface PY - 2021 AN - OPUS4-53968 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmies, Lennart A1 - Sonntag, U. T1 - Quantitative Fraktographie unter Verwendung klassischer Verfahren, Topographie-Daten und Deep-Learning N2 - Die Analyse von Bruchflächen wird in der Schadensanalyse meist auf der Basis von Erfahrungswissen vorgenommen, welches aus vorliegenden Untersuchungen, eigenen Vergleichsversuchen und aus der Literatur stammt. Durch Vergleiche mit bereits vorliegenden Bildern werden qualitativ Bruchmechanismen ermittelt. Grundlage sind zumeist zweidimensionale Bilder aus licht- und elektronenoptischen Verfahren. Quantitative Aussagen beziehen sich bislang beispielsweise auf makroskopische Anteile von Bruchmechanismen oder die Ausmessung von Schwingstreifen. In jüngerer Zeit gibt es vermehrt Ansätze, Computer-Algorithmen einzusetzen, die in der Lage sind, unterschiedlich strukturierte Bruchmerkmale zu finden und zu klassifizieren. Im hier vorgestellten IGF-Vorhaben „iFrakto“, IGF Vorhaben Nr.: 21477 N, werden licht- und elektronen-optisch Topographie-Bilder erzeugt und die gewonnenen 3D-Informationen zusammen mit den klassischen 2D-Bildern ausgewertet. Analytische Algorithmen und Machine Learning werden eingesetzt, um Bruchmerkmale zu analysieren, zu bewerten und mit Informationen aus einer fraktographischen Datenbank zu verknüpfen. Ziel ist die Bereitstellung von Software zur Unterstützung der Fraktographie in der Schadensanalyse. In diesem Beitrag werden erste Ergebnisse des Vorhabens vorgestellt. T2 - 55. Metallographie-Tagung CY - Online meeting DA - 29.9.2021 KW - Fraktographie KW - Machine Learning KW - Datenbank KW - REM KW - Topographie PY - 2021 AN - OPUS4-53491 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agea, Boris A1 - Walzel, S. T1 - 3D Druck unterstütz die Dekarbonisierung N2 - Suspensionsbasiertes Binder Jetting reduziert die Brennzeiten von technischer Keramik im Vergleich zu anderen 3d-druckverfahren signifikant. dabei wird nicht nur Energie beim Betrieb der Brennöfen gespart, sondern auch die Emission von Kohlendioxid beim Brennvorgang selbst gesenkt. KW - Schlickerdeposition PY - 2021 VL - 6 SP - 26 EP - 28 PB - Keramische Zeitschrift AN - OPUS4-53812 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa A1 - Balzer, B T1 - „Auffällige große Streifen“ im Schwingbruch N2 - Die „auffälligen großen Streifen“ sind von echten Schwingstreifen nur sehr schwer zu trennen, weil sie parallel zu den Schwingstreifen verlaufen und meistens ebenfalls nicht sehr groß sind. Die im Labor getesteten Proben zeigten, dass diese großen Streifen zusammen mit Verreibungen auftraten und „tire tracks“ („Reifenspuren“) verursachten. Dies wurde durch eine hochauflösende REM-Untersuchung bestätigt, die „tire tracks“ auf den „großen Streifen“ zeigte. Ein weiterer Hinweis ist die Änderung des R-Werts von -1 auf 0,1, was zu einer Bruchfläche ohne große Streifen und „tire tracks“ führt. T2 - Treffen der AG Fraktographie im Gemeinschaftsausschuss Rasterelektronenmikroskopie in der Materialprüfung CY - Online meeting DA - 19.11.2021 KW - Fractography KW - Fracture surface KW - SEM KW - REM KW - Fraktographie KW - Schwingstreifen KW - Fatigue PY - 2021 UR - https://dgm.inventum.de/widget/preview/45d8c33d-622b-43e2-8459-ba783394a723/611d133ebdac0611d133ebdac1 AN - OPUS4-53796 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghafafian, Carineh T1 - The effect of fiber orientation mismatch on scarf joint damage mechanisms under fatigue load N2 - Wind turbine rotor blades commonly fail before their projected 20-year lifespan largely due to defects that originate during manufacturing and are propagated by operational fatigue and environmental conditions. The cost-intensive replacement outcomes lead to a high loss of earnings, and are one of the inhibitors of wind turbine production. A potential repair alternative to restoring the mechanical properties of such lightweight fiber reinforced polymer (FRP) structures is to locally patch these areas with scarf joints. This type of repair allows for a smoother load distribution across the joint, and is favored especially on structures where minor aerodynamic contour changes are key. The effects of such repairs on the structural integrity, however, is still largely unknown. Building upon an understanding of the static load failure mechanism of GFRP scarf joints, presented at the ICCS23 Joint Event in 2020, the influence of the fiber orientation mismatch between parent and repair materials of 1:50 scarf joints on the failure mechanism of monolithic glass FRP specimens under cyclic fatigue load were examined in this study. Specimens with various layups were produced with the vacuum-assisted resin infusion (VARI) process using biaxial E-glass non-crimp fabric (NCF). The patch layers were then joined directly to the parent structure with the VARI using biaxial E-glass NCF with half the areal weight of the parent side to allow for better drapability. This mimics the soft-to-hard patch style utilized in wind turbine blade shell field repairs. The specimens were tested under uniaxial fatigue load, during which they were periodically monitored for damage onset. A comparison of the +45/-45° and 0/90° layups allowed for an understanding of the role of a highly mismatching fiber orientation in the transition zone between parent and patch material on the failure mechanism of the scarf joint. In addition to the tensile strength and stiffness property recovery assessment, a grayscale analysis using in-situ camera images determined the damage state leading to failure in each region across the scarf joint, which varied in the parent material versus scarf joint region, providing insight to the critical regions in this composite structure under cyclic loading. T2 - ICCS24 - 24th International Conference on Composite Structures CY - Online meeting DA - 14.06.2021 KW - Glass fiber reinforced polymers KW - Scarf repairs KW - Damage mechanisms PY - 2021 AN - OPUS4-52817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Entwicklung thermoelektrischer Multilayergeneratoren auf der Basis von Calciumcobaltit N2 - Thermoelectric generators can be used as energy harvesters for sensor applications. Multilayer thermoelectric generators (ML-TEGs) are a promising alternative to conventional π-type generators due to their high filling factor, high capability of automated production and the texturing potential during the production process. Calcium cobaltite is a promising thermoelectric oxide (p-type) with highly anisotropic properties. The following study shows the development of a textured unileg ML-TEG using ceramic multilayer technology. Tape-casting and pressure assisted sintering are applied to fabricate textured calcium cobaltite. Compared to conventional sintering, pressure assisted sintering increases the strength by the factor 10. Thermoelectric properties can be tuned either towards maximum power factor or towards maximum figure of merit depending on the pressure level. As electrical insulation material, a screen-printable glass-ceramic with high resistivity and adapted coefficient of thermal expansion is developed. From various commercial pastes a metallization with low contact resistance is chosen. The unileg ML-TEG is co-fired in one single step. The demonstrators reach 80% of the simulated output power and the power output is highly reproducible between the different demonstrators (99%). These results provide the first proof-of-concept for fabricating co-fired multilayer generators based on textured calcium cobaltite with high power factor, high density, and high strength. N2 - Thermoelektrische Generatoren können zum „Energy harvesting“ für den autarken Betrieb von bspw. Sensoren eingesetzt werden. Eine interessante Alternative zu den herkömmlichen π-Typ Generatoren sind auf Grund der höheren Leistungsdichte und der guten Automatisierbarkeit thermoelektrische Multilayergeneratoren. Calciumcobaltit ist ein vielsprechendes oxidisches Thermoelektrika (p-Typ) mit stark anisotropen Eigenschaften. Die hier vorgestellte Studie zeigt die Entwicklung von texturierten Unileg-Multilayer-Generatoren mittels keramischer Multilayertechnologie. Calciumcobaltit wird durch Foliengießen und druckunterstützte Sinterung texturiert. Im Vergleich zur konventionellen Sinterung verbessert sich die Festigkeit um den Faktor 10. Die thermoelektrischen Eigenschaften können je nach verwendetem Druckniveau hinsichtlich maximalem Power Factor oder hinsichtlich maximalem Gütefaktor optimiert werden. Ein Glaskeramikkomposit wird als Isolationsmaterial mit hohem Volumenwiderstand und angepasstem Wärmeausdehnungskoeffizienten entwickelt. Der Unileg-Multilayer-Generator wird in einem Schritt co-gesintert. Die hergestellten Demonstratoren erreichen 80% der simulierten Output-Leistung. Diese Ergebnisse stellen den ersten Machbarkeitsnachweis für die Herstellung von co-gesinterten Multilayer-Generatoren aus texturiertem Calciumcobaltit mit hohem Power Factor und hoher Festigkeit dar. T2 - Seminar des Lehrstuhls für Funktionsmaterialien, Universität Bayreuth CY - Online meeting DA - 18.06.2021 KW - Thermoelektrischer Generator KW - Multilayertechnik KW - Energy harvesting PY - 2021 AN - OPUS4-52834 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rabe, Torsten A1 - Eichler, J. A1 - Picht, G. A1 - Rossner, W. A1 - Stelter, M. A1 - Voigt, I. T1 - Digitalisierung der keramischen Fertigung - Herausforderungen und Chancen N2 - Dieses Strategiepapier zielt darauf ab, Akteuren und Entscheidungsträgern den Status der Digitalisierung in der keramischen Fertigung, erfolgreiche Best-Practice-Beispiele aber auch die Herausforderungen nahezubringen, die es nun anzugehen gilt. Es ist die Vision, die Keramikfertigung durchgehend zu digitalisieren und alle Schritte des Produktkreislaufs lückenlos über die gesamte Wertschöpfungs- und Nutzungskette zu vernetzen: also eine Keramikindustrie 4.0 zu etablieren. Das Strategiepapier erfasst zunächst die Spezifität der keramischen Fertigung und nimmt eine Analyse des gegenwärtigen Standes der Digitalisierung in der keramischen Industrie vor, auch anhand einiger ausgewählter Beispiele aus der industriellen Praxis. Auf Basis der wesentlichen Bausteine für eine Fertigungsdigitalisierung werden schließlich die Chancen für Keramikproduzenten sowie der erforderliche Forschungs- und Entwicklungsbedarf aufgezeigt. KW - Datenmanagement KW - Digitalisierung KW - Fertigungsprozess KW - Keramik KW - Sensorik PY - 2021 SP - 1 EP - 39 PB - Deutsche Gesellschaft für Materialkunde (DGM) und Deutsche Keramische Gesellschaft (DKG) CY - Köln ET - 1000 AN - OPUS4-52708 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraus, David A1 - Trappe, Volker T1 - Transverse damage in glass fiber reinforced polymer under thermo-mechanical loading N2 - In this study, the thermomechanical damage behavior of a glass fiber reinforced polymer material is investigated. The coefficients of thermal expansion of the composite as well as the matrix are measured in a wide temperature range. Quasi-static experiments with neat resin, unidirectional and multidirectional laminates are performed as well as fatigue experiments in a temperature range from 213 K to 343 K. This study focusses on the matrix damage due to fiber-parallel loading. A correlation between matrix effort, the dilatational strain energy of the matrix and the damage state of the specimen is demonstrated. It is shown that a fatigue life assessment can be performed with the aid of a temperature-independent master fatigue curve. KW - Composite KW - Glass fiber reinforced polymer KW - Thermo-mechanics KW - Fatigue KW - Damage KW - Temperature PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527462 DO - https://doi.org/10.1016/j.jcomc.2021.100147 SN - 2666-6820 VL - 5 SP - 100147 PB - Elsevier B.V. AN - OPUS4-52746 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghafafian, Carineh T1 - Restoring lightweight strength - Effect of localized repairs on the mechanical properties of composites sandwich structures N2 - As a type of high-performance composite material, glass-fiber reinforced plastics (GFRP) are favored for the construction of wind turbine rotor blades due to their high specific strength and stiffness properties (Grasse et al, 2010). During the blade manufacturing process, however, imperfections are often introduced, then further propagated due to harsh environmental conditions and a variety of loads (Caminero et al, 2013; Trappe et al, 2018). This leads to failure significantly before their designed lifespan. Since replacement of entire blades can be a costly potential outcome, localized repairs of the damaged region to restore structural integrity and thus lengthen its lifespan can executed in the field by technicians accessing the blades directly by suspended roping. These methods involve replacing the lost load path with a new material that is joined to the parent structure. In recent years, considerable studies have been conducted to investigate the influence of different repair parameters on the stress distribution, ultimate strength, impact behavior, and residual stresses of bonded repaired structures [Caminero et al, 2013; Trappe et al, 2018; Shufeng et al, 2014; Harman and Rider, 2011; Ahn and Springer, 2000; Lekou and Vionis, 2002). However, there currently do not exist any standardized repair procedures for wind turbine rotor blades. Namely, there is a lack of understanding about the effects of the layup of various repair methods, especially on the damage mechanism and fatigue life of the shells of rotor blades (Caminero et al, 2013; Trappe et al, 2018). This work therefore aims to begin to enrich this knowledge gap by testing the influence of different variables among repair patches on the mechanical properties of sandwich composite structures. Manufactured with the vacuum-assisted resin infusion (VARI) process, the test specimens are produced as a GFRP structure to represent the outer shell portion of a wind turbine blade, then repaired with a scarf joint. Scarf repairs are favored as the most efficient of the common structural joints, as the removal of the damaged area with angled walls leads to a nearly uniform shear stress distribution along the bond surface and no eccentricity in the load distribution (Caminero et al, 2013; Lekou and Vionis, 2002; Siener, 1992). The performance of specific layup methods of repair patches, namely a large-to-small versus small-to-large scheme of repair layers, is studied with static and load-controlled fatigue testing, then compared to pristine test specimens as well as to each other in terms of mechanical property restoration. The transition layer between repair and parent material is especially of interest in the performance of the structure. Damage onset, crack development and eventual failure are monitored in-situ with non-destructive testing methods, including thermography with an infrared camera system and a 3D deformation analysis system, to develop a more robust understanding of the effects of these repair concept variables on wind turbine blade shell structures. T2 - Wind Energy Science Conference CY - Online Meeting DA - 25.05.2021 KW - Glass fiber reinforced polymers KW - Wind turbine blade shell structures KW - Scarf joint repair PY - 2021 AN - OPUS4-52687 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 - Nolze, Gert T1 - CALM down: Identifying unknown phases N2 - CALM is software for determining the Bravais lattice type and the resulting lattice parameters from a single Kikuchi pattern. It requires the definition of 4 bands and a single bandwidth from which all other band positions as well as bandwidths are derived. For band detection, it uses the Funk transform, which allows detection of twice as many bands as usual. CALM works for any symmetry and requires low-noise patterns of at least 320x240 pixels. The resulting errors are <2% even for such small patterns, assuming good quality. The relative errors are <0.5%. However, this requires a projection centre position best derived from a sample of a cubic phase in CALM. However, this must have been recorded under identical conditions. Hundreds of Kikuchi patterns of phases with different symmetries were examined. T2 - Chemnitz MTEX Workshop 2021 CY - Online meeting DA - 08.03.2021 KW - EBSD KW - Gitterkonstanten KW - Phasenidentifikation PY - 2021 AN - OPUS4-52345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus T1 - Tensile Test: From Standard to PMD Application Ontology N2 - Data analysis methods play an important role in both the experimental and simulation-based digital description of materials but have so far been poorly structured. The platform Material Digital (PMD) should contribute to a standardized description of data processing methods in materials research. The goal is the quality assurance of the processes and the output data, the acquisition and definition of their accuracy as well as the interoperability between applications. Therefore, application ontologies are created to explicitly describe processes and test methods. In this presentation, the first efforts in creating a tensile test application ontology in accordance with the ISO standard 6892-1:2019-11 are shown. Especially, the path of ontology development to be pursued based on standards was focused. T2 - Onboarding Workshop der Plattform Material Digital (PMD) CY - Online meeting DA - 13.04.2021 KW - Ontology KW - Platform MaterialDigital KW - PMD KW - Tensile Test KW - Normung KW - Standardization PY - 2021 AN - OPUS4-52425 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stargardt, Patrick T1 - Modeling of the cooling behavior of thermoelectric multilayers N2 - Multilayered designs are an attractive approach towards cost-effective manufacturing of thermoelectric generators. Therefore, efforts are being made to co-fire two promising thermoelectric oxides, namely calcium cobaltite and calcium manganate. In this study, ceramic tapes, multilayer technology, and pressure-assisted sintering (PAS) were used. A major challenge for the PAS of low-sintered calcium manganate was cracking during cooling. A relationship between the properties of the release tape used during PAS and the cracking behavior was experimentally observed. To understand the origin of failure, reaction layers in the multilayer were analyzed and thermal stresses during cooling were estimated by finite element (FE) simulations. Thermal expansion, elastic properties, and biaxial strength of the thermoelectric oxides and selected reaction layers were determined on separately prepared bulk samples. The analysis showed that the reaction layers were not the cause for cracking of calcium manganate. Using the FE model, thermal stresses in different manganate multilayer designs with varying properties of the release tape were studied. The FEM study indicated, and a validation experiment proved that the thickness of the release tape has the main effect on thermal stresses during cooling in separately sintered calcium manganate. T2 - Keramik 2021 / Ceramics 2021 CY - Online Meeting DA - 19.04.2021 KW - Fem KW - Thermoelectric KW - Pressure assisted sintering PY - 2021 AN - OPUS4-52489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Charmi, Amir T1 - Mechanical anisotropy of LPBF 316L: a modeling approach N2 - The underlying cause of mechanical anisotropy in additively manufactured (AM) parts is not yet fully understood and has been attributed to several different factors like microstructural defects, residual stresses, melt pool boundaries, crystallographic and morphological textures. To better understand the main contributing factor to the mechanical anisotropy of AM stainless steel 316L, bulk specimens were fabricated via laser powder bed fusion (LPBF). Tensile specimens were machined from these AM bulk materials for three different inclinations relative to the build plate. Dynamic Young's modulus measurements and tensile tests were used to determine the mechanical anisotropy. Some tensile specimens were also subjected to residual stress measurement via neutron diffraction, porosity determination with X-ray micro-computed tomography, and texture analysis with electron backscatter diffraction (EBSD). A crystal plasticity model was used to analyze the elastic anisotropy and the anisotropic yield behavior of the AM specimens, and it was able to capture and predict the experimental behavior accurately. Overall, it was shown that the mechanical anisotropy of the tested specimens was mainly influenced by the crystallographic texture. T2 - 2. Online-Workshop "In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys " CY - Online meeting DA - 20.04.2021 KW - Anisotropy KW - Crystal plasticity KW - Additive manufacturing PY - 2021 AN - OPUS4-52603 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Portella, Pedro Dolabella A1 - Trappe, Volker T1 - Non-destructive characterization methods for polymer matrix composites N2 - The mechanical behavior of fiber reinforced composites with polymer matrix is governed by several mechanisms operating at different length scales. In this contribution we describe first non-destructive techniques which are adequate for the characterization of the fiber-matrix interphase at a microscopic level. In a second step we describe on a mesoscopic level the influence of manufacturing related elements on the mechanical properties of rotor blades for wind turbines. We concentrate on thermography, laminography and ultrasound in connection with mechanical testing systems. Finally we present methods for monitoring rotor blades by using embedded optical fibers. T2 - Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ, Brasilien CY - Online meeting DA - 26.11.2020 KW - Polymer matrix composites PY - 2020 AN - OPUS4-52043 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Portella, Pedro Dolabella T1 - Charakterisierung metallischer Werkstoffe für Anwendungen bei hohen Temperaturen N2 - In diesem Beitrag werden am Beispiel von Gasturbinen Verfahren zur Charakterisierung des werkstoff-mechanischen Verhaltens sowie der Gefügeentwicklung von Bauteilen für Anwendungen bei hohen Temperaturen aufgezeigt. Gasturbinen sind technisch gesehen sehr interessante Systeme, die in der Energietechnik und in der Luftfahrt von hoher wirtschaftlicher Relevanz sind. Seit Jahrzehnten gelten Gasturbinen als klassische Innovationstreiber, für ihre Entwicklung wurden bereits maßgebliche Erneuerungen im Bereich der Aerodynamik und der Werkstofftechnik hervorgebracht. T2 - Deutsche Physikalische Gesellschaft Senior Expert Netzwerk CY - Online meeting DA - 20.01.2021 KW - Superlegierungen KW - Gasturbinen PY - 2020 AN - OPUS4-52045 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Portella, Pedro Dolabella A1 - Krebber, Katerina T1 - Fiber Optic Sensors for SHM - From Laboratory to Industrial N2 - The paper highlights the research activities in Germany and Europe in the development of distributed fiber optic sensor for structural health monitoring (SHM) like the monitoring of geotechnical and civil infrastructures and presents selected results achieved within these projects. T2 - Conaendi & IEV 2021 CY - Online meeting DA - 09.03.2021 KW - Fiber KW - Optic KW - SHM PY - 2021 AN - OPUS4-52254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sandoval Saldias, Janina T1 - Chloridische Salzschmelzen als latente Wärmespeicher N2 - Latente Wärmspeicher auf der Basis von NaCl-KCl-MgCl2 Mischungen stellen eine kostengünstige Option für die Energiespeicherung von Prozesswärme dar. Der Beitrag gibt einen Überblick über die materialwissenschaftlichen Herausforderungen im System Salz-Legierung, welche gelöst werden müssen, um diese Speichertechnologie industriell zu etablieren. T2 - DMG Sektionstreffen Angewandte Mineralogie und Kristallographie CY - Online Meeting DA - 25.02.2021 KW - Wärmespeicher KW - Korrosion KW - Salzschmelzen PY - 2021 AN - OPUS4-52234 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Stephan-Scherb, Christiane ED - Schorr, S. ED - Weidenthaler, C. T1 - Crystallographic challenges in corrosion research N2 - High-temperature corrosion is a widespread problem in various industries. As soon as a hot and reactive gas (CO2, O2, H2O, SO2, NOx, etc.) is in contact with a solid, physico-chemical processes at the surface and interfaces lead to material degradation. The processes are dynamic and controlled by thermodynamic and kinetic boundary conditions. Whether a reaction product is protective or not depends on various factors, such as chemical composition of the solid and the reactive media, surface treatment as well as diffusion and transport paths of cations and anions. Resulting chemical and structural inhomogeneities with the corrosion layers are characterized by off stoichiometry within cationic and anionic sub lattices. The competitive processes can be studied by various techniques of applied crystallography. This chapter gives an overview on the challenges of chemical-structural Analysis of reaction products by crystallographic methods such as X-ray diffraction and X-ray near-edge structure spectroscopy and scanning electron microscopy electron backscatter diffraction (SEM-EBSD) for corrosion science. KW - High-temperature corrosion KW - Oxidation KW - Diffraction KW - Spectroscopy KW - Oxides PY - 2021 DO - https://doi.org/10.1515/9783110674910-009 SP - 291 PB - De Gruyter ET - 1 AN - OPUS4-52903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Thermo-mechanical fatigue of glass fiber reinforced polymer N2 - Glass fiber reinforced polymer (GFRP) materials in practical applications have to endure cyclic mechanical loading in a wide temperature range (e.g. aircraft applications, automotive, wind turbine blades). In this study the static strength and fatigue behavior of GFRP was investigated in a temperature range from 213 K to 343 K. Therefor the coefficients of thermal expansion of the composite as well as the matrix are measured in this temperature interval. The inverse laminate theory was extended and used to calculate the inter fiber-failure effort for a virtual UD-layer according to the layer wise strength approach. The experimentally determined results are compared with the micro-mechanical model according to Krimmer, which has been enhanced to include the effect of temperature and fiber-perpendicular failure modes. A correlation between matrix effort, the dilatational strain energy of the matrix and the damage state of the specimen is demonstrated. It is shown that a fatigue life assessment can be performed with the aid of a temperature-independent master fatigue curve, as it was similar done for the fatigue behavior of CFRP and GFRP to very high load cycles at room temperature. T2 - ICFC8 - The 8th International Conference on the Fatigue of Composites CY - Online meeting DA - 23.06.2021 KW - Glass fibre reinforced plastics KW - Fatigue KW - Thermo-mechanical-loading PY - 2021 AN - OPUS4-52910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agea Blanco, Boris A1 - Walzel, S. A1 - Chi, J. A1 - Lüchtenborg, J. T1 - Making Binder Jetting Really Work for Technical Ceramics - Additive Manufacturing of Technical Ceramics N2 - As an alternative shaping method to the traditionally used processes, additive manufacturing (AM) can produce economical ceramic components in small lot sizes and/or with complex geometries. Powder-based additive manufacturing processes like binder jetting are popular in the field of metal AM. One reason is the increased productivity compared to other AM technologies. For ceramic materials, powder-based AM technologies result in porous ceramic parts, provided they are not infiltrated. CerAMing GmbH unites the advantages of powder-based processes with the production of dense ceramic by means of the Layerwise Slurry Deposition. By using a suspension, a high packing density of the powder bed is achieved which leads to high green body densities. Due to this advantage the approach overcomes the problems of other powder-based AM technologies. Furthermore, a very economical debinding time allows the production of parts with high wall thicknesses. KW - Additive Manufacturing KW - Binder Jetting KW - Layerwise Slurry Deposition KW - Lithography-based technologies KW - Technical Ceramics PY - 2021 SP - 49 EP - 52 PB - Göller Verlag CY - Baden-Baden AN - OPUS4-52948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus T1 - Tensile Test Ontology used in Platform Material Digital (PMD) N2 - Data analysis methods play an important role in both the experimental and simulation-based digital description of materials but have so far been poorly structured. The platform Material Digital (PMD) is supposed to contribute to a standardized description of data processing methods in materials research. The goal is the quality assurance of the processes and the output data, the acquisition and definition of their accuracy as well as the interoperability between applications. Therefore, application ontologies are created to explicitly describe processes and test methods. In this presentation, the first efforts within the joint project PMD in creating a tensile test application ontology in accordance with the ISO standard 6892-1:2019-11 are shown. Especially, the path of ontology development to be pursued based on standards was focused. Furthermore, the presentation includes a live demonstration of queries possibly performed to query data that was uploaded in the PMD triple store. T2 - Online Workshop: An introduction to the semantic web and ontologies CY - Online meeting DA - 23.04.2021 KW - Ontology KW - Tensile Test KW - Platform Material Digital KW - PMD KW - Knowledge Graphs KW - Semantic Web PY - 2021 AN - OPUS4-52949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bettge, Dirk A1 - Le, Quynh-Hoa T1 - Entwicklung einer fraktographischen Symbolik N2 - Bei der Untersuchung von Bruchflächen werden zunächst Beobachtungen gemacht, d.h. makroskopische und mikroskopische Merkmale analysiert und in Bildern dokumentiert. Im zweiten Schritt werden anhand der gefundenen Merkmale Rissverlauf und Bruchmechanismen ermittelt. Abschließend sollen diese Ergebnisse in einem Bericht oder Gutachten zusammengefasst werden. Hierbei ist eine skizzenhafte Darstellung der fraktographischen Befunde hilfreich für das Verständnis des Lesers. Ein vorgefertigter fraktographischer Symbolsatz würde dies erheblich vereinfachen. Skizzen von fraktographischen Befunden sind in der Literatur recht häufig zu finden, z.B. in der VDI 3822 oder dem ASM Handbook Fractography, allerdings gibt es hierzu keine umfassende Systematik, wie sie z.B. aus der Meteorologie (Wetterkarten), Geographie (Landkarten, Seekarten) oder Geologie (Bodenkarten) seit langer Zeit bekannt sind. Deshalb wird hier der Versuch unternommen, einen Symbolsatz zu entwickeln und zur Verfügung zu stellen, mit dessen Hilfe fraktographische Befunde in eindeutiger und übersichtlicher Weise veranschaulicht werden können. Der fraktographische Symbolsatz ("Fracto Graphics") befindet sich in Entwicklung, ist offen zur Diskussion sowie für Verbesserungen. T2 - 55. Metallographie-Tagung CY - Online meeting DA - 29.9.2021 KW - Fraktographie KW - Symbolik KW - Schadensanalyse PY - 2021 AN - OPUS4-53433 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Wolf, Marcus A1 - Kranzmann, Axel T1 - Corrosion and corrosion fatigue of steels in downhole CCS environment - A summary N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO₂-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO₃ and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO₂: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied. KW - Steel KW - High alloyed steel KW - Corrosion KW - Corrosion fatigue KW - Carbon capture and storage PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531391 DO - https://doi.org/10.3390/pr9040594 SN - 2227-9717 VL - 9 IS - 4 SP - 1 EP - 33 PB - MDPI CY - Basel AN - OPUS4-53139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja A1 - Kranzmann, Axel T1 - Effects of saline aquifer water on the corrosion behaviour of martensitic stainless steels during exposure to CO2 environment N2 - Immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4 and X5CrNiCuNb16-4 at T=60 °C and ambient pressure and p=100 bar were performed for 700 h - 8000 h in a CO₂-saturated synthetic aquifer environment similar to CCS-sites in the Northern-German-Basin. Main corrosion products are FeCO₃ and FeOOH. Highest surface corrosion rates at ambient pressure are 0.8 mm/year for 42CrMo4 and lowest 0.01 mm/year for X5CrNiCuNb16-4. Corrosion rates at 100 bar (max. 0.01 mm/year for 42CrMo4, X20Cr13, X46Cr13) are generally lower than at ambient pressure (<0.01 mm/year for X35CrMo4, X5CrNiCuNb16-4). Heat treatment to martensitic microstructure offers good corrosion resistance. T2 - 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15 CY - Abu Dhabi, United Arab Emirates DA - 15.03.2021 KW - CCS KW - Corrosion KW - High alloyed steels PY - 2021 DO - https://doi.org/10.2139/ssrn.3812248 SP - 1 EP - 12 PB - SSRN CY - Rochester, NY AN - OPUS4-53140 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja A1 - Wolf, Marcus A1 - Kranzmann, Axel T1 - Evaluating corrosion and corrosion fatigue behavior via laboratory testing techniques in highly corrosive CCS-environment N2 - In CCS environment (carbon capture and storage) pipes are loaded statically and/or cyclically and at the same time exposed constantly to the highly corrosive hot thermal water. Experimental procedures such as ambient pressure immersions tests, in-situ corrosion fatigue experiments using a flexibly designed corrosion chamber at ambient pressure and a specially designed corrosion chamber at high pressure. Experimental set-ups for push/pull and rotation bending load are introduced. The corrosion behavior and lifetime reduction of high alloyed steels (X46Cr13, 1.4043), (X5CrNiCuNb16-4, 1.4542) and (X2CrNiMoN22-5-3, 1.4462) is demonstrated (T=60 °C, geothermal brine: Stuttgart Aquifer flow rate: 9 l/h, CO₂). T2 - 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15 CY - Abu Dhabi, United Arab Emirates DA - 15.03.2021 KW - Steel KW - Supercritical CO2 KW - Pipeline KW - Corrosion KW - CO2-storage PY - 2021 DO - https://doi.org/10.2139/ssrn.3812193 SP - 1 EP - 11 PB - SSRN CY - Rochester, NY AN - OPUS4-53142 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 - Pfennig, Anja T1 - Vom Blended Learning zum Full Online – so einfach geht es nicht – Praxiserfahrungen zum Einsatz von Lehrfilmen N2 - Mit Beginn der Covid-19 Pandemie und dem damit verbundenen ausschließlichen Lehren im online-Format war die Hoffnung verbunden ein Blended Learning Lehrformat für die Studieeingangsphase ohne viel konzeptionelle Änderungen übertragen zu können. Der Kurs Werkstofftechnik als Grundlagenfach für den Maschinenbau baut sich auf inverted classroom Lehrszenarien auf, deren Lerngrundlage hierfür eigens produzierte und auf das Lernziel abgestimmte Lehrfilme und Lightboard-Vorlesungen darstellen. Im Kontext der Studieneingangsphase bieten audiovisuell stimulierende Lehrfilme umfassende Lernmedien, wenn sie analog der Lerninhalte einem technischen und didaktischen Qualitätsanspruch genügen. In der Praxis des SS2020 und WS2020/21 hat sich gezeigt, dass die Moderation und Durchführung eines online-Kurses sich deutlich von dem eins blended learning-Kurses unterscheidet. Um denselben Lernerfolg bei Studierenden zu erzielen, müs-sen Anforderungen viel genauer und detaillierter verfasst werden, Studierende enger und persönlicher begleitet werden und Lehrfilme und Lernmedien in einen Gesamtzusammenhang gestellt werden. Im Folgenden werden aus persönlicher Erfahrung heraus niederschwellige, zum Teil ungewöhnliche praktische Erfahrungen zur erfolgreichen Umsetzung von Lehrfilm-basierten inverted classroom Lehrszenarien zusammengefasst und im Hinblick auf die online-Lehre bewertet. T2 - 19. Fachtagung Bildungstechnologien (DELFI) CY - Bonn, Germany DA - 13.09.2021 KW - Inverted classroom KW - Lehrfilm KW - Lehrfilmformate KW - Online KW - Covid-19 PY - 2021 SP - 289 EP - 295 AN - OPUS4-54154 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja T1 - Improving Learning Outcome for GSL (German as a Second Language) Students in a Blended Learning Cumulative Assessment Material Science Course N2 - First year students especially with migration background and language deficiencies rate material science in mechanical engineering as one of the fundamental courses with high work load and necessity of language skills due to the descriptive nature of the course. Therefore a blended learning course structure using based on inverted classroom teaching scenarios was established. Heart of the self-study period are visualizing peer-to-peer lecture films supported by micro-lectures along with various online teaching materials. Although students with migration background generally scored lower in tests due to the lack of language skills improved learning outcomes are demonstrated in high quality class discussions and in overall understanding. This paper introduces the learning structure and graded activities, evaluates the course and compares results of native German-speaking students to those of students with migration background. KW - Portfolio KW - Diversity KW - Blended learning KW - Inverted classroom KW - Lecture films PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541557 DO - https://doi.org/10.17706/ijeeee.2021.11.3.93-100 SN - 2010-3654 VL - 11 IS - 3 SP - 93 EP - 100 AN - OPUS4-54155 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja T1 - How flipped classroom teaching methods in first year studying succeed N2 - Flipping the classroom is a method to let students study on their own and then take time to discuss their questions and do extended hands-on lectures or exercises in class – or in the case of the covid-19 pandemic during plenary online sessions. First year mechanical engineering students use different teaching materials (mainly lecture videos, lightboard videos and micromodule lectures) to study from a distance and comprehend the principle underlying science in theory. Then the online plenary lectures offer the opportunity to apply their knowledge and transfer different scientific aspects of the course to get the bigger picture. Exercises, worked solutions, selfassessed tests and peer-instruction during present time help students to check on their learning progress. However, the self-study periods and (online) plenary sessions need to be guided carefully. To meet the course learning outcome and overcome the diversity of a first year class various practical leads have to be fulfilled to turn flipped classroom teaching into success. T2 - 7th International Conference on Higher Education Advances (HEAd’21) CY - Valencia, Spain DA - 20.06.2021 KW - Inverted classroom KW - Flipped classroom KW - Online teaching KW - Lecture videos KW - First year students PY - 2021 DO - https://doi.org/10.4995/HEAd21.2021.12792 SP - 1211 EP - 1219 AN - OPUS4-54156 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Wolf, M. A1 - Kranzmann, Axel T1 - Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment—A Summary N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/− applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied. KW - Steel KW - High alloyed steel KW - Corrosion fatigue KW - Cabon capture and storage KW - CCS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541626 DO - https://doi.org/10.3390/pr9040594 VL - 9 IS - 4 SP - 594 PB - MDPI AN - OPUS4-54162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blaeß, Carsten T1 - Viskose Rissschließung in Gläsern und Glasmatrixkompositen N2 - Um die Langzeitbeständigkeit von Hochtemperatur-Festoxidbrennstoffzellen (SOFC) sicherzustellen, ist das grundlegende Verständnis der viskosen Schließung oder Heilung von Rissen, als Folge wechselnder thermischer oder mechanischer Belastung, in Gläsern und teilkristallinen Materialien ein entscheidender Faktor. In Glas ist die Rissheilung hauptsächlich durch viskoses Fließen bestimmt. In teilkristallinen Schmelzen bewirkt der kristalline Volumenanteil die Erhöhung der effektiven Viskosität. Um die Auswirkungen des kristallinen Volumenanteils auf die Rissheilung zu ergründen, wurden Glasmatrixkomposite mit variierten inerten kristallinen Fülleranteilen, die während der Wärme-behandlung konstant blieben, hergestellt. Verwendet wurde ein kristallisationsträges Natrium-Calcium-Silicatglas und ZrO2 als inerter Füller. Komplexe, reproduzierbare Rissstrukturen wurden durch Vickers-Eindrücke erzeugt und die viskose Rissschließung während isothermer Wärmebehandlungs-schritte mittels Laser-Scanning-Mikroskopie verfolgt. Die Untersuchungen zeigen, dass, verglichen zum füllerfreien Glas, der kristalline Phasenanteil die effektive Viskosität erhöht und dadurch großräumiges Fließen verlangsamt. Dies verzögert das Aufweiten der Risse. Dieser Effekt erschwert die Rissverkürzung und führt oftmals zu großen gerundeten Kavitäten und dadurch zu einer verzögerten Rissschließung. Wird dieses Aufweiten verringert, ist zunächst ein lokales viskoses Fließen der Restglasphase weiterhin gegeben, sodass sich die Risse sogar schneller schließen. Für kristalline Anteile > 27 Vol% bildet sich dann ein stabiles Perkolationsgerüst aus, das die weitere Rissschließung auch lokal unterbindet. Nur innerhalb größerer glasiger Bereiche ist hierbei noch eine Rissschließung zu beobachten. Ein Optimum der Risslängenverkürzung konnte bei 17 Vol% beobachtet werden. T2 - 94. Glastechnische Tagung CY - Online meeting DA - 10.05.2021 KW - Glas KW - Hochtemperaturbrennstoffzelle KW - Glasmatrixkomposit KW - Rissheilung PY - 2021 AN - OPUS4-54245 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, A. A1 - Kranzmann, Axel T1 - Understanding the Anomalous Corrosion Behaviour of 17% Chromium Martensitic Stainless Steel in Laboratory CCS-Environment—A Descriptive Approach N2 - To mitigate carbon dioxide emissions CO2 is compressed and sequestrated into deep geological layers (Carbon Capture and Storage CCS). The corrosion of injection pipe steels is induced when the metal is in contact with CO2 and at the same time the geological saline formation water. Stainless steels X35CrMo17 and X5CrNiCuNb16-4 with approximately 17% Cr show potential as injection pipes to engineer the Northern German Basin geological onshore CCS-site. Static laboratory experiments (T = 60 ◦C, p = 100 bar, 700–8000 h exposure time, aquifer water, CO2-flow rate of 9 L/h) were conducted to evaluate corrosion kinetics. The anomalous surface corrosion phenomena were found to be independent of heat treatment prior to exposure. The corrosion process is described as a function of the atmosphere and diffusion process of ionic species to explain the precipitation mechanism and better estimate the reliability of these particular steels in a downhole CCS environment. KW - Corrosion KW - Steel KW - High alloyed steel KW - Corrosion mechanism KW - CCS PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545700 DO - https://doi.org/10.3390/cleantechnol4020014 VL - 4 IS - 2 SP - 239 EP - 257 PB - MDPI AN - OPUS4-54570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bettge, Dirk T1 - MGA Round Robin Test on Al-AM Fatigue Testing - Fractographic Results N2 - Presentation of results of an investigation of fracture mechanisms and crack start sites of an additive manufactured aluminium alloy after fatigue testing. Collaboration within the MGA initiative (Mobility Goes Additive). T2 - MGA Mid Term Meeting 2022 CY - Berlin, Germany DA - 05.07.2022 KW - Aluminium Alloy KW - Fractography KW - Additive Manufacturing PY - 2022 AN - OPUS4-55192 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Dynamic mechanical analysis of epoxy-matrix cross linking measured in-situ using an elastomer container N2 - A new patented dynamic mechanical analysis (DMA) is presented, where the tensile, bending- or torsional stiffness of a media can be characterized in-situ during the phase transition from liquid to solid. An epoxy system, e.g. Hexion L285/H287, is filled into an elastomer container, such as a silicone tube. This can be mounted into a conventional DMA and, based on a linear viscoelastic approach, the storage modulus (E’;G’), the loss modulus (E’’;G’’) and the loss angle tan(delta) can be measured at constant temperature as a function of time in order to investigate the liquid to sol-gel to solid transition. With this new method, the stiffness increase as a result of the cure process can be directly measured more precisely than with a rheometer in a shear plate set-up, because using an elastomer container gives a defined cross section for calculating the Young’s modulus. T2 - 20th European Conference on Composite Materials, ECCM20 CY - Lausanne, Switzerland DA - 26.06.2022 KW - Dynamic mechanical analysis (DMA) KW - Thermoset polymers KW - Cure process KW - Cross linking PY - 2022 AN - OPUS4-55213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Suárez Ocano, Patricia T1 - I n situ monitoring of growing oxidation of the chemically complex alloy AlMo 0.5 NbTa 0.5 TiZr in the high temperature regime using synchrotron radiation Preliminary results N2 - The chemically complex alloys (CCAs) that contain mostly refractory elements (rCCAs), may be highly resistant to heat and load, which makes them attractive candidates for use at extremely high temperatures associated with many technological applications, e.g. aeroengine turbines. However, the field of CCAs, especially their resistance in harsh (oxidative) and hot environment is still young and not much experimental evidence for the understanding mechanisms in this regime is available, which the proposed study addresses. For safe use in structural applications, in addition to their mechanical performance, the environmental resistance of this alloy is also critical. Surface degradation can significantly decrease the mechanical resistance during high temperature exposure, leading to premature failure. The AlMo0.5NbTa0.5TiZr rCCA only contains Al as a protection candidate and it is composed of a coherent B2/bcc nanoscopic cube-on-cube interweave and an hexagonal phase. The evaluation of the oxidation process in the AlMo0.5NbTa0.5TiZr rCCA in the heat-treated state has not been assessed yet. The proposed study focusses on a deeper understanding of the formation mechanism and growth kinetics of oxides at high temperature in the AlMo0.5NbTa0.5TiZr rCCA using synchrotron radiation. Due to the envisaged high temperature structural applications, the alloy is evaluated in an oxidation environment specifically between 800°C and 1000°C. T2 - Large scale facility-based techniques SPP meeting CY - Online meeting DA - 02.11.2021 KW - Refractory chemically complex alloys KW - Oxidation behavior KW - Microstructural analysis KW - Synchrotron radiation PY - 2021 AN - OPUS4-54383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra T1 - Bestimmung der Partikelgrößenverteilung mittels Zentrifugen-Sedimentationsverfahren nach ISO 13318-2 (Küvette) N2 - Im Vortrag werden das Messprinzip des Zentrifugen-Sedimentationsverfahrens erläutert und die Anforderungen der zugrundeliegenden Normen diskutiert. Es schließen sich umfangreiche Ausführungen zur praktischen Durchführung der Messung, insbesondere auch zu den vorbereitenden Arbeiten, sowie zur Auswertung der Rohdaten an. Gezeigt werden die Validierung sowie ein Beispiel zur regelmäßigen Verifizierung des Verfahrens. Nach Beispielen und Vergleichen zu Ergebnissen mit anderen Messverfahren, wird das Verfahren in einer Zusammenfassung bewertet. T2 - Seminar Rheologie und Stabilität von dispersen Systemen CY - Potsdam, Germany DA - 09.05.2022 KW - Nano powder KW - Cetrifugal Liquid Sedimentation CLS KW - Particle size determination PY - 2022 AN - OPUS4-54863 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghafafian, Carineh T1 - Fully-reversed fatigue behavior of scarf joint repairs for wind turbine blade shell applications N2 - Due to manufacturing imperfections which can propagate to damage under in-service loads, wind turbine rotor blades, made primarily of glass fiber reinforced polymers (GFRP), often fail significantly before their design life. To enable a quick and cost-effective return to service, localized repairs can be executed by technicians in the field, directly accessing the blades by suspended roping. Scarf joint repairs, shown to be highly efficient with a smooth load transition across angled joint walls and a restored aerodynamic profile, are the focus of this study. The damage mechanisms of these structures were examined under fully-reversed mechanical cyclic loading with a load ratio R = -1, which was made possible on the coupon scale by a custom designed anti-buckling support. The number of cycles to failure were compared across load levels. While the scarf joint ratio was held constant at 1:50, known from industry and literature to be a good compromise between restored mechanical properties and repair size, the layup sequence was varied between small-to-large and large-to-small. Hereby the effect of the presence of resin pockets and fiber orientation mismatch between the parent and repair structure on the failure mechanism as well as fatigue strength of ±45° GFRP scarf joint repair structures was studied. Strain development across the joint length was measured to assess stiffness degradation in addition to the fatigue strength recovery of scarf joint structures with respect to pristine reference specimens. Grayscale analysis was used to monitor the damage state leading to fracture across the specimens. Post-mortem fractography analysis with light microscopy described the global failure mechanisms as well as local damage distribution within the structure, all of which provided insight to critical variables in scarf joint GFRP structures under fully-reversed mechanical cyclic loading, allowing for the tailoring of such repairs on wind turbine blade shells for maximum restoration of service life. T2 - 20th European Conference on Composite Materials (ECCM20) CY - Lausanne, Switzerland DA - 26.06.2022 KW - Glass fiber reinforced polymers KW - Scarf repairs KW - Fatigue PY - 2022 AN - OPUS4-55638 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 - Junge, P. A1 - Stargardt, Patrick A1 - Kober, D. A1 - Greinacher, M. A1 - Rupprecht, C. T1 - Thermally Sprayed Al2O3 Ceramic Coatings for Electrical Insulation Applications N2 - Thermal spraying enables a fast and propelling way to additively deposit various ceramics as electric insulators, which are used in conditions where polymers are not suitable. Alumina (Al2O3) is among the most employed materials in the coating industry since it exhibits good dielectric properties, high hardness, high melting point while still being cost-effective. Various parameters (e.g. feedstock type, plasma gas mixture, plasma power) significantly influence the resulting coating in terms of microstructure, porosity, crystallinity, and degree of un-or molten particles. As a consequence, these parameters need to be investigated to estimate the impact on the electrical insulating properties of thermally sprayed alumina. This study focuses on the development of a novel electric insulation coating from Al2O3 feedstock powders deposited via atmospheric plasma spray (APS). The microstructure, porosity, and corresponding crystallographic phases have been analyzed with optical microscopy, XRD, and SEM images. To achieve an understanding of the parameters influencing the electrical insulation performance of the manufactured coatings, an in-depth analysis of the fundamental dielectric parameters e.g., DC resistance, breakdown strength, dielectric loss tangent, permittivity is presented. T2 - International Thermal Spray Conference and Exposition 2022 CY - Vienna, Austria DA - 04.05.2022 KW - Thermal Spray KW - Alumina KW - Dielectric properties PY - 2022 SP - 1 EP - 8 AN - OPUS4-55821 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -