Synthesis of Fe-substituted CoSb3-based skutterudite Co4–xFexSb12 by mechanical alloying-hot pressing-annealing

Abstract

Mechanical alloying and preparation of Fesubstituted CoSb₃-based skutterudite Co_{4 x}Fe_xSb₁₂ (x"d1) were studied. All the compositions showed similar kinetics in mechanical alloying, where the skutterudite phase was kinetically more favorable than CoSb₂ phase initially. Then the latter became the strongest phase when milling time was increased. A single phase skutterudite structure could not be obtained via mechanical alloying. Hot pressing on powders milled for 10 hours yielded mostly skutterudite phase as well as minor residual Sb impurity, and single phase skutterudite compounds were finally obtained for Co_{4 x}Fe_xSb₁₂ (x"d0.65) after annealing at 650?C for 48 hours. The maximal solubility for Fe substitution seemed to be reached at x = 0.65.

Keywords

thermoelectric materials, skutterudite, mechanical alloying, sintering