Low temperature synthesis of nanocrystalline Sb2Te3 by mechanical alloying

Sb40Te60 thermoelectric compound was fabricated via mechanical milling of bismuth and tellurium as starting materials. Effects of the milling time and heat treatment were investigated. X-ray diffraction (XRD) was used for the characterization of the ball-milled powders. Thermal behavior of the mechanically alloyed powders was studied by differential thermal analysis (DTA) and the morphological evolutions were monitored by scanning electron microscopy (SEM). Results showed that the reaction between Sb and Te initiated after 5 h of milling and completed after 10 h. The synthesized Sb2Te3 had anisotropic property with the mean grain size of 13 nm at the end of milling. Also this compound could not be formed during heating by DTA at low temperatures (<500 °C). Under the sintering conditions the maximum values of electrical conductivity and power factor were found to be 860 (Ω cm)−1 and 45 (μW cm−1 K−1), respectively.