Synthesis and thermoelectric performance of a p-type Bi0.4Sb1.6Te3 material developed via mechanical alloying

Abstract

A p-type Bi0.4Sb1.6Te3 thermoelectric compound was fabricated via mechanical alloying of bismuth, antimony and tellurium elemental powders as starting materials. The mechanically alloyed compositions were sintered through a spark-plasma sintering (SPS) process. The effect of the milling time was investigated. In order to characterize the powders obtained via mechanical alloying, X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analysis were used. The morphological evolution was studied by scanning electron microscopy (SEM). Results showed that the p-type Bi0.4Sb1.6Te3 compound was formed after 2h of milling. Further, the variation of milling time showed that the synthesized phase was stable. All the powders exhibit the same morphology albeit with slight differences. Measurements of the electrical resistivity, Seebeck coefficient and thermal conductivity were performed in the temperature range 300–520K for the SPS samples. The resulting thermoelectric figure of merit ZT reaches a maximum of 1.2 at 360K for the p-type bulk material with a 5h milling time. This study demonstrates the possibility of preparing thermoelectric materials of high performance and short processing time.