Regensburg 2004 – scientific programme

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M: Metallphysik

M 18: Postersitzung

M 18.8: Poster

Tuesday, March 9, 2004, 14:30–16:30, Saal C

Phase formation by interfacial reactions in the BaO - TiO₂ system — •Andreas Graff, Stephan Senz, and Dietrich Hesse — Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany

Model experiments concerning phase formation during BaTiO₃ genesis by interfacial reactions in ceramics were performed to identify the reaction mechanism. Reaction products between BaO vapour and rutile (TiO₂) single crystals with different orientations were investigated by XRD and analytical TEM. BaTiO₃ was found at the surface of the reaction layer. It had a well-defined orientation relation to the rutile substrate. In addition to BaTiO₃, Ti-rich phases and pores were formed. This observation is discussed by an outdiffusion of titanium and oxygen from the BaTiO₃-TiO₂ interface. For a more detailed study of this behavior, reaction couples of BaTiO₃ thin films on rutile single crystal substrates were prepared. Solid state reactions were initiated by heat treatment in air. These experiments are compared with the BaO-TiO₂ reaction.