Bi掺杂量对Mg-Si-Sn-Bi材料热电性能的影响  

Effect of Bi Doping Content on the Thermoelectric Properties of Mg-Si-Sn-Bi Materials

作　　者：宋贵宏[1] 孟雪[1] 杨明川[2] 胡方[1] 乔瑞庆[1] 陈立佳[1] 

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110870 [2]沈阳理工大学装备工程学院,沈阳110168

出　　处：《人工晶体学报》2016年第12期2790-2794,共5页Journal of Synthetic Crystals

基　　金：国家自然科学基金(51472167)

摘　　要：利用粉末冷压成型及真空烧结制备了不同Bi掺杂量的Mg-Si-Sn-Bi材料,并对制备材料组成和热电性能进行研究。结果表明,制备材料由Mg2Sn、Mg2Si和Mg2（Si,Sn）固溶体相组成。随测试温度的增加,制备材料的电阻率都急剧减小,这是典型的半导体特征。在研究范围内,掺杂Bi元素含量增加,制备材料的电阻率开始逐渐减小,但Bi掺杂量增加到一定值后,材料的电阻率又增加,而且掺杂后的材料电阻率都低于未掺杂的。制备材料的Seebeck系数是负值,表明这些材料都为n型半导体。对于掺杂Bi的材料,随着测试温度由室温增加到730 K,测得的Seebeck系数绝对值开始时轻微增加,约在240~270 K达到最大值,再随着温度增加,Seebeck系数绝对值又显著单调减小。对于掺杂Bi元素的材料,随Bi掺杂量的增加,Seebeck系数的绝对值先减少后增加,这是掺杂造成载流子浓度增加和散射过程加大相互竞争的结果。掺杂Bi的Mg-Si-Sn材料的功率因子都高于未掺杂的材料,且Bi掺杂量增加,制备材料的功率因子显著增加。对于1.29at%Bi和1.63at%Bi掺杂量的材料,功率因子分别在500 K和530 K存在一个极大值。The Mg-Si-Sn materials doped with different content of Bi were prepared by vacuum sintering after powder cold press molding, the composition and thermoelectric properties were studied. The results show that the prepared materials are composed of Mg2Sn, Mg2Si and Mg2 （Si, Sn） solid solution phase. The electrical resistivity of the prepared materials sharply decreases as measuring temperature increasing, which characterizes that these materials are semiconductor. The electrical resistivity of the prepared material first gradually decreases and then increases as the Bi doping content increasing within the scope of our studied content. However, the electrical resistivity of the doping Bi materials is less than that of without doping Bi materials. The Seebeek coefficient is negative, which suggests that the prepared material is n-type semiconductor. The absolute value of Seebeek coefficient slightly enhances and reaches a maximum value at 240-270 K then follows a monotonous reduction with measuring temperature from room temperature to 730 K. For a materials doped Bi, the absolute value of Seebeck coefficient first decreases and then increases as Bi content increasing, which is mutual competitive results of the carrier concentration increasing and the scattering process enhancement due to doping Bi. The power factor of materials doping Bi is higher than that of materials without doping Bi and the power factor of materials greatly increases as Bi doping content increasing. The power factor reaches maximum value at 500 K and530 K for the materials doping 1.29 at% and 1.63 at% Bi content, respectively.

关 键 词：Mg-Si-Sn材料 Bi掺杂 SEEBECK系数 电阻率 真空烧结 

分 类 号：TQ175[化学工程—硅酸盐工业]