Fabrication and characterization of Bi/sub 2/Te/sub 3/-Sb/sub 2/Te/sub 3/ based thermoelectric materials by powder-extrusion-sintering technique

Abstract

Despite high thermoelectric performance, the commercial applications of Bi/sub 2/Te/sub 3/-Sb/sub 2/Te/sub 3/ based thermoelectrics are limited mainly because of production cost due to complicated processing steps. In this study, a new approach to the powder-extrusion-sintering method, which is intended to fabricate a sound sintered material by the simultaneous application of pressure and heat, was investigated. This method is expected to be suitable for low cost production of Bi/sub 2/Te/sub 3/-Sb/sub 2/Te/sub 3/ materials because of the possibility of semi-continuous fabrication processing. It was possible to achieve high density (/spl ges/95% of theoretical density) products by adjusting variables, such as; die angle, die hole length, powder size, extrusion pressure and temperature. Thermoelectric properties of sintered specimens were measured, and discussed to achieve optimum fabrication conditions.