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Thermoelectric Properties of Nb-Doped SrTiO3 / TiO2 Multiphase Composite

Published online by Cambridge University Press:  31 January 2011

Kiyoshi Fuda
Affiliation:
fudak@ipc.akita-u.ac.jp, Akita University, 1-1 Tegatagakuen-Cho, Akita, 010-8502, Japan
Kenji Murakami
Affiliation:
murakami@ipc.akita-u.ac.jp, Akita University, Appl. Chem. for Env., Akita, Japan
Tomoyoshi Shoji
Affiliation:
shoji@ipc.akita-u.ac.jp, Akita University, Appl. Chem. for Env., Akita, Japan
Shigeaki Sugiyama
Affiliation:
Akita pref. Ind. Tech. Center, Akita, 010-1623, Japan
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Abstract

In this study, we fabricated and examined a series of multiphase type composites constructed of Nb-doped SrTiO3 / TiO2 fine particles. The composition of the composites and the sintering temperatures were selected in a two-phase region where a perovskite SrTiO3 and a rutile TiO2 phases coexist. The composites obtained here were found to commonly have a mosaic type texture constructed of TiO2 and SrTiO3 fine particles with a typical size of about 500 nm. In some samples we also found additive phases such as Sr6Ti7Nb9O42. The thermal conductivity values measured for the most samples with different contents are ranged between 2 and 5 Wm-1K-1. The values are apparently lower than the value for single crystal SrTiO3 samples presented in literature. A sample with rather low relative density of about 80% showed a quite low thermal conductivity, about 1 Wm-1K-1. Taking account the other TE data, e.g. Seebeck coefficient and electrical conductivity, we calculated dimensionless figure of merit, ZT, to be at maximum 0.24 at 600°C.

Type
Research Article
Copyright
Copyright © Materials Research Society 2009

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