Formation of cerium-filled skutterudite thermoelectric materials in the sintering of gas-atomized powder

A formation process of the CeFe3CoSb12 thermoelectric materials with a fill ed skutterudite structure prepared using the gas-atomized powder was studie d. Fine powder particles were prepared by a fast Ar gas jet and characteriz ed. It was found that these particles consist of the CeFe3CoSb12, FeSb2, Fe Sb and Sb. The differential scanning calorimetry curve indicates that therm oelectric materials were sintered through two exothermic reactions, i.e. th e low-temperature one probably corresponds to the oxidation of Sb and the h igh-temperature one matches the skutterudite phase formation from latter th ree phases. Sintering conditions were adjusted in order to reduce the Sb ox idation and to ensure the skutterudite phase formation. As the result of th ermoelectric 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 mate rials. The maximum dimensionless figure-of-merit of 0.63 was obtained for t he most improved specimen at 700 K.