Effect of spark plasma sintering parameters on the electrical and thermal properties of Bi0.5Sb1.5Te3 sintered body

Abstract

This study investigated the effect of spark plasma sintering parameters on the electrical and thermal properties of Bi0.5Sb1.5Te3 sintered body. The Bi0.5Sb1.5Te3 powders were prepared by the combination of the melting and mechanical milling processes. The mechanical treated powders were sintered by using spark plasma sintering process under various sintering conditions. The change in the microstructure and phase with sintering conditions were analyzed using FE-SEM and XRD. The thermoelectric property of the sintered body was evaluated by measuring the Seebeck coefficient, electric resistivity and thermal conductivity. Grain size of Bi0.5Sb1.5Te3 sintered body was increased as sintering temperature or sintering time was increased and sintering temperature affected more than sintering time in grain growth. The sintered body by using spark plasma sintering process was shown an orientation on thermal and electrical properties. We assume that these orientation of thermal and electrical properties is because of the anisotropy of crystal structure of Bi-Te system. The orientation of these sintered bodies was increased as the sintering temperature and time was increased. Seebeck coefficient and electrical resistivity was decreased on the perpendicular direction to pressure and thermal conductivity of the parallel direction to pressure was decreased.