Pressureless-sintering and thermoelectric properties of lead selenide ceramics

As an attempt to establish pressureless-sintering technique of heavy-metal chalcogenide thermoelectric materials; sintering behavior and thermoelectric properties of PbSe ceramics were investigated. Under appropriate sintering conditions, sintered densities higher than 97% of theoretical density were attained. The volatilization of the components was effectively suppressed by the use of a powder bed and the optimization of sintering temperature and time. Although an oxide phase, PbSeO₃, was contained in the starting powder, it was eliminated by sintering powder compacts under a reducing atmosphere. The electrical conductivity increased with increasing sintering temperature, while Seebeck coefficient was not much dependent on the sintering conditions. Potential superiority of pressureless-sintering technique to pressure-sintering techniques such as hot-pressing was evidenced in terms of obtaining oxide-free, highly dense thermoelectric ceramics