超声化学结合放电等离子烧结制备In_4Se_3化合物的热电性能研究

Thermoelectric Properties of In_4Se_3 Synthesized by Combing Sonochemical and SPS Method

采用超声化学和后续还原热处理工艺合成了单相In4Se3化合物粉体,并结合放电等离子烧结技术(SPS)制备了致密的块体材料.对所得的块体材料的微结构和热电传输性能进行了系统研究.结果表明,块体样品的晶粒细小、排列紧密并存在显著的择优取向,同时样品中存在大量精细的层状结构,这使得块体样品的电热传输性能也表现出明显的各向异性.由于具有较高的Seebeck系数和较低的热导率,沿着SPS压力方向上样品表现出较好的热电性能,其最大ZT值在700 K可达到0.56,这与其它物理技术制备的In4Se3多晶材料的性能相当.

Single-phase In4Se3 powders were synthesized by a sonochemical method combined with subsequent deoxidizing heat-treatment,and a bulk sample was prepared via a spark plasma sintering（SPS） method.The phase composition,microstructures and thermoelectric transport properties of the as-prepared bulk sample were studied.The bulk sample possesses refined crystalline and obvious anisotropy observed in the different directions,where a large number of fine layered structures exist along the SPS pressing direction.Therefore,the thermoelectric properties of the bulk sample also show significant anisotropy.Owing to higher Seebeck coefficient and lower thermal conductivity,a better ZT is achieved in direction of the SPS pressure compared with the perpendicular direction.As a result,the maximum ZT reaches 0.56 at 700 K,which is comparable with that of the samples synthesized by other physical techniques.