Study of structural and dimensional characteristics of the melt spun p-Bi0.5Sb1.5Te3 powders compacted by vacuum hot pressing and spark plasma sintering

Abstract

P-type thermoelectric Bi0,5Sb1,5Te3 powders were obtained by the melt spinning technique (extremely rapid quenching from the liquid state) and their structural and dimensional characteristics were characterized. The crystallographic group and the lattice parameters of the powders correspond to those for Bi0,5Sb1,5Te3 crystallized in equilibrium conditions which suggests the identity of the crystal structure. The powders were compacted by vacuum hot pressing and spark plasma sintering. We found that the partial axial texture [001] directed along the axis of pressure application could be formed during the compacting of the powders. Temperature dependences of the thermoelectric characteristics of the compacted material were measured in a direction perpendicular to the pressure application axis in the 100–700K range. It is demonstrated that the compacted samples possess low thermal conductivity while retaining the Seebeck coefficient and the electrical conductivity values comparable to crystallized material; therefore ZT reaches 1.05–1.15 in the 330–350K range which indicates high prospects of applying these technologies.