NiSe_2块体材料的制备及热电性能研究

Synthesis and Thermoelectric Properties of NiSe_2 Bulk Material

结合机械合金化(MA)与放电等离子烧结(SPS)工艺制备了NiSe_2块体热电材料。研究了MA球磨时间和SPS烧结温度对NiSe_2热电材料的物相、显微组织以及电热传输性能的影响。结果表明:当转速为425 r/min,球磨40 h后合成了约45 nm的NiSe_2纳米粉体。NiSe_2粉体是一种直接禁带半导体,禁带宽度为2.653 eV,其块体呈n型导电特征。烧结温度为773 K时,NiSe_2块体材料在323 K获得最大功率因子101μW·m^(-1)·K^(-2),热导率为7.5 W·m^(-1)·K^(-1),最大ZT值为0.0045。

NiSe2 thermoelectric materials were prepared by the combination of mechanical alloying （MA） and spark plasma sintering （SPS）. The effects of MA time and SPS temperature on the phase structure, microstructure, thermoelectric and optical properties were investigated. The results show that NiSe2 nanopowders with the grain sizes of 45 nm are synthesized by applying MA at 425 r/min for 40 h. It is proved that NiSe2 powder material is a direct band gap semiconductor with an optical band gap of about 2.653 eV and the NiSe2 bulk possesses a n-type semiconductive characteristic. The NiSe2 bulk prepared by applying SPS at 773 K attains a maximum power factor of 101 μW·m^-1.K2 along with a thermal conductivity 7.5 W·m^-1·K^-1 and the largest ZTvalue 0.0045.