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Thermoelectric performance and crystal phase of calcium cobalt oxides sintered in oxygen gas
Author(s) -
Tahashi Masahiro,
Takahashi Makoto,
Goto Hideo
Publication year - 2018
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/jace.15349
Subject(s) - sintering , seebeck coefficient , materials science , crystallite , oxygen , thermoelectric effect , cobalt , analytical chemistry (journal) , partial pressure , electrical resistivity and conductivity , phase (matter) , calcium hydroxide , mineralogy , metallurgy , chemistry , composite material , thermal conductivity , thermodynamics , physics , organic chemistry , chromatography , electrical engineering , engineering
Calcium hydroxide and tricobalt tetroxide were used as starting materials in a Ca:Co molar ratio of 3:4 and sintered at 1073‐1373 K in a pure oxygen atmosphere. Polycrystalline single‐phase Ca 3 Co 4 O 9 was obtained at all sintering temperatures in oxygen gas, and comparison with a sample sintered in air showed that controlling the oxygen partial pressure during sintering was important. In the sample sintered at 1373 K, the Seebeck coefficient was slightly lower than that of the samples sintered at lower temperatures, but the resistivity was decreased by half, so the power factor was doubled.