Rapid Fabrication of Thermoelectric Compounds by Flash Sintering

Abstract

In various kinds of functional material, its properties can be controlled by microstructure refinement in order to optimize its performance. Especially for a thermoelectric material, the reduction of thermal conductivity by the microstructure refinement can enhance its utility for thermoelectric energy conversion devices. For the fabrication of a fine-grain sintered body, a powder metallurgical technique is commonly used. In particular, electric current sintering is an effective means of microstructure refinement. Recently, flash sintering, which is defined as sintering with a duration in the order of seconds, is expected as an energy efficient sintering technique. In addition, from an application viewpoint, the high production rate of flash sintering is expected to bring improved productivity to mass production of sintered parts. In this paper, flash sintering of thermoelectric compound was conducted by the sintering apparatus specially designed for flash sintering. With a current feed duration of 1 s, Sb2Te3 sintered sample having a thermoelectric performance comparable to that of a sample prepared by a conventional current sintering can be obtained. This significant reduction in the sintering time can result in the energy consumption for the sintering process being decreased to less than 1% of that required for conventional current sintering.