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Sintering Temperature Dependence of Thermoelectric Performance and Crystal Phase of Calcium Cobalt Oxides
Author(s) -
Tahashi Masahiro,
Tanimoto Tetsuya,
Goto Hideo,
Takahashi Makoto,
Ido Toshiyuki
Publication year - 2010
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2010.04026.x
Subject(s) - sintering , materials science , crystallite , cobalt oxide , seebeck coefficient , thermoelectric effect , calcium oxide , cobalt , phase (matter) , oxide , analytical chemistry (journal) , mineralogy , chemistry , metallurgy , composite material , thermodynamics , thermal conductivity , physics , organic chemistry , chromatography
Polycrystalline samples were synthesized by a conventional solid‐state reaction. As starting materials, Co 3 O 4 and Ca(OH) 2 were mixed in a molar ratio of Ca:Co=3:4 and sintered at 1073–1373 K. The compound phases and thermoelectric properties of the resulting products were dependent on the sintering temperature. X‐ray diffraction analysis showed that the Ca 3 Co 4 O 9 compound was stable up to 1193 K and that Ca 3 Co 2 O 6 was formed at 1273 K. At 1373 K, the sample decomposed into cobalt oxide and calcium oxide. A maximum power factor of about 100 μW/(K 2 ·m) at 873 K was obtained for the Ca 3 Co 4 O 9 phase sintered at 1193 K.