ガス噴霧法により得られたCoSb<SUB>3</SUB>系熱電材料の焼結と熱電特性

Abstract

The development of mass production process of thermoelectric materials is necessary to practical use. The most important thing is how to make large amounts of high quality thermoelectric materials with high productivity and low cost. Skutterudite structure materials are new kinds of thermoelectric materials which is recently paid much attention. From these view points, Skutterudite structure materials were produced by gas atomizing and sintering process. The materials examined in this study are CoSb3 of the typical Skutterudite structure material, (CoPdPt)Sb3 of the substituted structure n-typed material and CeFe3CoSb12 of the filled Skutterudite structure p-typed material. Sintering was tried with hot pressing process or spark plasma sintering process. Each gas atomized powder contains every necessary element with fine structure almost the same stoichiometric ratio of aimed thermoelectric material. Accordingly gas atomized powders could be sintered into thermoelectric materials in a short time without mixing and grinding process by both sintering methods. These lead to high productivity and low cost in manufacturing. Although there is no remarkable difference of thermoelectric properties between hot press sintered and spark plasma sintered materials, it was confirmed that sintering time required can be shorter for spark plasma sintering than for hot press sintering. CeFe3CoSb12 has some problems to attain high ZT value. On the other hand, (CoPdPt)Sb3 produced by gas atomizing and sintering process had almost same value of ZT which was obtained in laboratory scale. The combination process of gas atomizing and sintering methods is useful for mass production of thermoelectric materials.