Thermoelectric and Mechanical Properties of Bi-Te Materials Prepared by Hot Press Method

Abstract

The purpose of this work is to present thermoelectric and mechanical properties of Bi-Te polycrystalline materials. Semiconducting ceramics of p- and n-type bismuth telluride were prepared by a hot press method. High purity row materials of Bi, Sb, Te and Se were used for the alloy preparation and the sample with a dimension of 144mm in diameter and 35mm in hight was obtained. The tensile and compressive strengths of n-type were 20.6 and 118MPa, respectively, being independent of hot press directions. A thermomechanical analysis (TMA) was used to determine the thermal expansion coefficient of 1.59×10-5K-1 for n-type and 1.69×10-5K-1 for p-type. The thermal expansion coefficient was denpendent on the hot press direction. The thermoelectric modules were fabricated to determine their figure of merit of 2.3×10-3K-1 at 20°C. From the present observations, the polycrystalline bismuth telluride was found to have the same thermoelectric properties as zone-melting ones.