Thermoelectric Properties of Bismuth Telluride Based Materials Prepared by Powder Metallurgy Processing

摘要

Poiycrystalline samples of Bi_2Te_3 based alloys were prepared by powder metallurgy processing including a melting-grinding and a sintering procedure of compacted pellets. Two sintering procedures as hot-pressing and spark plasma sintering (SPS) were employed. The thermoelectric properties and mechanical strength were measured in all case. Thermoelectric properties for p-type (Bi_(0.25)Sb_(0.75))_2Te_3 and n-type Bi_2(Te_(0.2)Se_(0.8))_3 changed with sintering temperature in both sintering methods. Mechanical strength and relative density increase with sintering temperature in two sintering procedures. The results firmly suggest that both sintering procedures are promising to obtain high performance thermoelectric materials.