Thermoelectric properties of fine-grained PbTe bulk materials fabricated by cryomilling and spark plasma sintering

Abstract

Dense fine-grained PbTe bulk materials without oxide phases are fabricated using a process that combines cryomilling (mechanical milling at cryogenic temperature) and spark plasma sintering (SPS). In the process, micro-grained PbTe powder is cryomilled into nanocrystalline powders, which are then rapidly densified into dense bulk samples with fine grains by SPS at 573 K. The effect of cryomilling on the composition ratio, microstructure, and thermoelectric properties of sintered PbTe samples is investigated. Experimental results indicate that when the grain size decreases to the nano-scale, the Seebeck coefficient increases, the thermal conductivity decreases, and the electrical conductivity only slightly changes for all sintered samples. According to the results, the combination of cryomilling and spark plasma sintering can improve the thermoelectric transport properties of PbTe bulk materials. ©2011 The Japan Institute of Metals.