Effect of Synthesis Procedure on Thermoelectric Property of SiGe Alloy

SiGe thermoelectric material has been synthesized by ball milling combined with hot pressing (HP) or spark plasma sintering (SPS). Effects of ball milling time, powder to ball weight ratio and sintering method on microstructure and thermoelectric properties of SiGe are studied. The results show that longer ball milling time leads to decreased density and worse electrical properties. In the sintering process, SPS results in much larger density and better electrical properties than HP. The Si 0.795 Ge 0.2 B 0.005 sample prepared by 2 h ball milling combined with SPS obtains a maximum power factor of 3.0 mW m −1 K −2 at 860 K and ZT of 0.95 at 1000 K.