|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||The Influence of Impurities on the Interfacial Chemistry of Niobium – Alumina High-temperature Refractories
||Michael K. Eusterholz, Torben Boll, Alexander Kauffmann, Reshma Sonkusare, Tilo Zienert, Dirk Endler, Vincent Ott, Anja Weidner, Julian Gebauer, Christos G. Aneziris, Michael Stüber, Martin Heilmaier, Bastian Kraft
|On-Site Speaker (Planned)
||Michael K. Eusterholz
Composites of coarse-grained refractory metals and refractory α-Al2O3-ceramic offer an outstanding combination of thermomechanical and functional properties, e.g., low shrinkage, excellent resistance to thermal shock, and electrical conductivity. Conventionally sintered composites from technical grade raw materials of α-Al2O3 and Nb include impurity elements and carbides alongside oxides, which further develop after exposure at a typical application temperature of 1500°C to 1800°C. To understand the principles of formation of such phases we investigated α-Al2O3 substrates, which were sputter-coated with Nb as a model system beside the technical grade material. This allows to independently study the influence of various impurity elements at the interface. The chemistry was investigated on different length scales. Backscatter electron imaging and electron backscatter diffraction were used to elucidate the microstructure, while transmission electron microscopy and atom probe tomography advanced the understanding of nano-scale segregation and phase formation at the phase boundary.
||Composites, High-Temperature Materials,