纳米AlN分散的Bi_(85)Sb_(15)低温热电性能研究

Thermoelectric properties of nano-AlN dispersed Bi_(85)Sb_(15) at cryogenic temperature

利用机械合金（MA）和放电等离子（SPS）烧结方法,制备出Bi85Sb15/x mol%AlN（x=0,0.1,0.2,0.3）块体材料。在77—300 K温区内,测试了块体材料的电导率、Seebeck系数、霍尔系数和热导率,并由此计算出材料的zT值。结果表明：纳米AlN分散的Bi85Sb15材料,随着AlN含量的增加,样品的迁移率升高,从而明显提高材料的电导率,但Seebeck系数绝对值呈减小趋势。适量的纳米AlN的引入可以形成散射中心,增加对声子的散射作用,降低热导率。当基体Bi85Sb15中加入0.1mol%AlN时,其zT值在250 K取得最大值～0.32,比基体在此温度下的zT值提高了45%。

Bi85Sb15/x mol% AlN（ x = 0,0. 1,0. 2,0. 3） bulk materials were fabricated by mechanical alloying（ MA） and spark plasma sintering（ SPS）. The electrical conductivities,Seebeck coefficients,Hall coefficients and thermal conductivities were investigated in the temperature range from 77 K to 300 K. As a result,with the increase of nano-AlN content,the electrical conductivities were improved significantly because of the increasing mobility but the absolute Seebeck coefficients tended to decrease. The proper nanoAlN dispersed in Bi85Sb15can be scatter centers and decrease the thermal conductivity. The maximum zT value of ～ 0. 32 was achieved at 250 K for the sample Bi85Sb15/0. 1 mol% AlN,which was increased 45%than that of Bi85Sb15matrix at the same temperature.