Improvement in Thermoelectric Properties by High Crystal Orientation in (Bi_(0.25)Sb_(0.75))_2Te_3 and Bi_2(Te_(0.9)Se_(0.1))_3

摘要

In this study, mechanical alloying followed by pulse discharge sintering (MA-PDS) was employed to synthesize the bulk (Bi_(0.25)sb_(0.75))_2Te_3 and Bi_2(Te_(0.9)Se_(0.1))_3 thermoelectric materials and then the compacts were pressed. The effect of pressing on the crystal orientation and thermoelectric performance of the compacts was investigated. The microstructural characterizations of the pressed compacts by XRD and SEM indicated a high crystallographic orientation, namely a preferred (0 0 15) (0 0 18) orientation was formed after pressing. The grain boundary sliding in the compacts by pressing was suggested to be responsible for the development of the highly preferred orientation.