パルス放電焼結法によって作製したn型CoSb<SUB>3</SUB>化合物の熱電特性に及ぼすアルミナナノ粒子添加の影響

Abstract

Thermoelectric power generation is a promising green energy system recovering waste heat. CoSb3 skutterudite compound is a candidate material for thermoelectric power generation. For improving thermoelectric performance of the material, it is necessary to lower the thermal conductivity. In this work, Al2O3 nanoparticles were added and dispersed by mechanical grinding (MG) into n-type CoSb3 compound prepared by pulse discharge sintering (PDS) method. Over long MG treatment brought high electrical resistivity, lowering thermoelectric performance of the Al2O3 nanoparticles added CoSb3 compound. Seebeck coefficient almost did not change regardless of additional amount of Al2O3 nanoparticles. Increasing additional amount of Al2O3 nanoparticles brought increasing electrical resistivity and decreasing thermal conductivity. It is found that there is an optimal additional amount of Al2O3 nanoparticles that leads to improvement of thermoelectric performance of the CoSb3 compound. The maximum thermoelectric performance (ZT=0.58) was achieved at 684 K in the CoSb3 compound including Al2O3 nanoparticles of 0.1 mass%.