Solid stae reaction synthesis of skutterudite compounds Fe_xCo_4-xSb₁₂ and thermoelectric properties

Skutterudite compounds Fe_xCo_4-xSb₁₂ were synthesized by solid state reaction using high-purity powders of Co, Fe, and Sb as starting materials. Fe_xCo_4-xSb₁₂(x = 0-1.0) compounds were obtained at 900-1000 K. The lattice constant of Fe_xCo_4-xSb₁₂ increased with increasing substitution of Fe for Co sites. Carrier concentration and electrical conductivity increased with increasing Fe content. Seebeck coefficient decreased and T_opt of Seebeck coefficient shifted to higher temperature with increasing Fe content. Lattice conductivity was reduced significantly by substitution of Fe for Co sites. The maximum ZT value of 0.5 was obtained for Fe_0.92Co_3.08Sb₁₂ at 750K.