Mg_(3)Sb_(2)材料的自蔓延燃烧合成与热电性能研究

Research on Self-propagating Combustion Synthesis and Thermoelectric Performances of Mg_(3)Sb_(2) Material

采用自蔓延燃烧合成-等离子活化烧结(SHS-PAS)合成法制备了一系列Mg3+xSb2(0≤x≤0.4)样品,合成了Mg_(3)Sb_(2)单相产物,并研究了自蔓延燃烧过程中Mg过量对本征p型Mg_(3)Sb_(2)材料的晶体结构、热电性能的影响规律,进而确定了通过SHS-PAS方法合成Mg_(3)Sb_(2)的材料化学计量配比的最佳Mg过量量,优化了本征p型Mg_(3)Sb_(2)材料的热电性能。结果表明,在Mg_(3+x)Sb_(2)(0≤x≤0.4)样品中,当Mg过量量达到x=0.3时,样品在723 K下电导率为1744.5 S·m^(-1),Seebeck系数为345.7μV·K-1,总热导率0.65 W·m^(-1)·K^(-1),获得最佳ZT值达0.23,相比已有文献报道的传统固相反应法制备的本征Mg_(3)Sb_(2)材料提高达150%。

A series of Mg_(3+x)Sb_(2)(0≤x≤0.4) samples were prepared by SHS-PAS method and the single phase products of Mg_(3)Sb_(2) was synthesized.Moreover,the effects of excess Mg on the lattice structure and thermoelectric properties of intrinsic p-type Mg_(3)Sb_(2) material during self-propagating combustion were studied.The optimum Mg excess amount of the stoichiometric ratio of Mg_(3)Sb_(2)synthesized by SHS-PAS method were determined.The results show that Mg_(3.3)Sb_(2) sample shows the highest ZT value of 0.23 at 723 K.With the conductivity of 1744.5 S·m^(-1),the Seebeck coefficient of 345.7μV·K^(-1),the total thermal conductivity of 0.65 W·m^(-1)·K^(-1),which is 150%higher than that of the intrinsic Mg_(3)Sb_(2)reported in the literature prepared by traditional solid-state reaction method.