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DS: Fachverband Dünne Schichten
DS 42: Thermoelectric materials IV: Glass, sintered materials (Focused session – Organizers: Meyer, Heiliger)
DS 42.3: Talk
Friday, March 30, 2012, 12:15–12:30, H 2032
Ca3Co4O9 based ceramics and glass-ceramics as high temperature stable oxide thermoelectrics — •Matthias Jost1,2, Julian Lingner1,2, Martin Letz2, and Gerhard Jakob1 — 1Johannes-Gutenberg Universität, Institut für Physik, Staudinger Weg 7, Mainz D-55128 — 2Schott AG, Hattenbergstraße 10, Mainz D-55122
Oxidic thermoelectric materials are a good alternative to the now more common thermoelectric materials, such as PbTe, SiGe, BiSb or Bi2Te3, because of their thermal stability, chemical stability, low toxic level and good availability of the raw materials. In our presentation, we will give a brief review about the determined thermoelectric properties of our Ca3Co4O9 ceramics and Ca3Co4O9 glass-ceramics. Ca3Co4O9 ceramics were first discussed by Ryoji Funahashi in 1999. The ceramics have been processed using conventional sintering. Therefor we mixed CaCO3 and CoO powders. The mixture was ground, calcined, pulverized, and pressed into pellets. These pellets were cold isostatically pressed and after that sintered at different temperatures. The glass was melted in a platin-iridium crucible, casted into a steel mold, quenched and cooled down in an annealing lehr. After that, it was ceramized in an infrared-furnace. The ceramics/glass-ceramics were examined by X-ray diffraction and samples were prepared out of the pellets/glass-ceramic-blocks. Electrical conductivity, thermal resistivity and the Seebeck coefficient of these samples were measured for different temperatures and from these values ZT were calculated.