パルス放電焼結法によって作製したn型CoSb₃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

抄録

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%.