Abnormal Crystal Growth and Transport Properties of Sintered (Bi_(0.2)Sb_(0.8))_2Te_3 Thermoelectric Alloys with Ag Addition

摘要

A new processing technique, mechanical alloying followed by pulse discharge sintering (MA-PDS), has been successfully developed in our laboratory to fabricate the bulk Bi_2Te_3-based thermoelectric materials. ~(1)) In this processing, MA allows the formation of extremely fine (Bi, Sb)_2Te_3 solid solution crystallites from the elemental powders of Bi, Sb and Te through a sequence of collision events inside a ball mill. MA powders are subsequently compacted into bulk by PDS. In comparison to the conventional hot-pressing process, the very short time and the low temperature exposure of MA powders achieved by PDS offers the best means to retain fine grain size in compacts.