Thermoelectric properties of Bi-Sb composite prepared by mechanical alloying method

Abstract

To study the mechanical alloying process and the properties of thermoelectric semiconductor with fine dispersed ceramic particles, Bi-Sb alloys with addition of fine BN and ZrO/sub 2/ were prepared by mechanical alloying. The milled powders were sintered by hot pressing. The Bi/sub 92.5/Sb/sub 7.5/ solid solution with fine dispersion of BN and ZrO ceramic particles were successfully synthesized. The sintered composites show very fine microstructures in which average grain size are less than one micron. The thermal properties of composites were measured by laser flash method at room temperature. The electrical properties were measured by Van der Pauw method at room temperature and at 77 K. The BN addition has obtained larger reduction of thermal conductivity compared to ZrO/sub 2/. The thermal conductivity has been reduced to 20% of the reported value of Bi-Sb single crystal, which achieved with 10 vol% addition of BN.