Synthesis of CoSb3 skutterudite by mechanical alloying

In the present work, elemental powder mixtures with an atomic ratio of Co:Sb=1:3 were mechanically alloyed by high-energy ball milling in a planetary ball mill. It is found that the CoSb3 compound (e-phase) was synthesized after milling for 10 h, and its concentration increased with prolonged milling time. The CoSb2 compound (δ-phase) was observed when milling for longer than 20 h, but single phase CoSb3 skutterudite could not be obtained even on further milling for 50 h. It is shown that single phase CoSb3 could be synthesized easily by annealing the as-MAed powders in vacuum at 700 °C, and the annealing time could be as short as 1 h for the powders milled for over 10 h.