Materials Based on Solid Solutions of Bismuth and Antimony Tellurides Formed by Rapid Melt Crystallization Methods

Abstract

p-type Bi_0.5Sb_1.5Te₃ solid solutions prepared by hot pressing and the extrusion of powders prepared by rapid melt crystallization methods such as melt spinning and melt crystallization in a liquid are investigated. The morphology of the powders, the sample cleavage surface, and their microstructure are investigated using optical microscopy, scanning electron microscopy, and scanning tunneling microscopy. The mechanical properties of the samples are investigated by room-temperature compression tests. The Seebeck coefficient, electrical conductivity, and thermal conductivity of the materials are measured in the temperature range of 100–600 K. The highest limiting compressive strength σ_B = 145 MPa at 300 K and maximal thermoelectric efficiency (ZT)_max = 1.34 at 370 K are found for materials extruded from granules prepared by melt crystallization in water and ground in a ball mill.