Regensburg 2022 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 4: Structural Materials
MM 4.8: Vortrag
Montag, 5. September 2022, 12:15–12:30, H46
Influence of oxygen and carbon on the chemistry at the niobium/alumina interface in a refractory composite material — •Michael Eusterholz1, Torben Boll1, Alexander Kauffmann1, Reshma Sonkusare1, Vincent Ott1, Julian Gebauer1, Bastian Kraft1, Anja Weidner2, Michael Stüber1, Sven Ulrich1, and Martin Heilmaier1 — 1Karlsruhe Institute of Technology (KIT) — 2TU Bergakademie Freiberg (TUBAF)
High-temperature processes such as steel casting impose harsh conditions on materials, which thus require excellent properties, including creep strength and resistance to thermal shock. Composites based on coarse-grained refractory metals and refractory ceramics promise superior performances due to adjustable mechanical and electrical properties.
Conventionally sintered composites from technical grade raw materials of α-Al2O3 and Nb include impurity elements that form carbides alongside oxides during synthesis. To understand the principles of formation, we investigate α-Al2O3 substrates sputter-coated with Nb as model materials beside the technical grade material. As the latter is subjected to carbon and oxygen containing gases during sintering, we compare the effect of oxygen and carbon overexposure on the ceramic-metal interface and contrast these results with a heat treatment with unaffected interface. Electron microscopy techniques elucidate the microstructure, while atom probe tomography advances the understanding of nano-scale phase formation at the phase boundary which are decisive for the material properties and corrosion resistance.