日本金属学会誌

J. Japan Inst. Metals, Vol. 65, No. 10 (2001),
pp. 955-960

Formation of Cerium-Filled Skutterudite Thermoelectric Materials in the Sintering of Gas-Atomized Powder

Hiroyuki Tanahashi1, Yoriko Ohta1, Hiroshi Uchida1,, Yoshio Itsumi2,, Akio Kasama1 and Kakuei Matsubara3

1Japan Ultra-high Temperature Materials Research Institute, Ube 755-0001
2Materials Research Laboratory, Kobe Steel, LTD., Kobe 651-2271

3Department of Electronics and Computer Science, Science University of Tokyo in Yamaguchi, Onoda 756-0884

Abstract:

A formation process of the CeFe3CoSb12 thermoelectric materials with a filled skutterudite structure prepared using the gas-atomized powder was studied. Fine powder particles were prepared by a fast Ar gas jet and characterized. It was found that these particles consist of the CeFe3CoSb12, FeSb2, FeSb and Sb. The differential scanning calorimetry curve indicates that thermoelectric materials were sintered through two exothermic reactions, i.e. the low-temperature one probably corresponds to the oxidation of Sb and the high-temperature one matches the skutterudite phase formation from latter three phases. Sintering conditions were adjusted in order to reduce the Sb oxidation and to ensure the skutterudite phase formation. As the result of thermoelectric measurements, the Seebeck coefficient increases, and the both electric conductivity and thermal conductivity decrease in the temperature range 300-850 K mainly with decreasing the residual Sb in the sintered materials. The maximum dimensionless figure-of-merit of 0.63 was obtained for the most improved specimen at 700 K.


(Received May 22, 2001)

Keywords:

cobalt-antimonide, cerium filling, skutterudite, thermoelectric material, gas-atomizing, differential scanning calorimeter, sintering, formation process


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