放电等离子烧结制备Zn-Cu-Sb-Bi合金的热电性能

Thermoelectric properties of Zn-Cu-Sb-Bi alloys prepared by spark plasma sintering

采用真空熔炼/放电等离子烧结(SPS)方法制备P型Zn4-xCuxSb3-xBix(x=0～0.8)材料,研究该合金的组织结构和热电性能。结果表明,x<0.2时,Zn4-xCuxSb3-xBix材料的Seebeck系数随x值增大而增大,当x=0.2时达到最大值;而当x>0.2后,Seebeck系数又随x值增大而下降。在x=0.2和487 K的条件下,Seebeck系数达到最大值,为249.2μV/K。合金的电导率随Cu和Bi含量增加而增大。借助Zn4-xCuxSb3的热扩散系数,计算得到材料的热导率随x值增大而增大;在574 K,x=0.4时,Zn4-xCuxSb3-xBix合金的最大热电优值(ZT)为0.53,比同温度下β-Zn4Sb3合金的ZT值大0.07。

P-type Zn4-xCuxSb3-xBix （x=0-0.8） alloys were prepared through vacuum melting and spark plasma sintering, and their structures were characterized. The results show that the Seebeck coefficient （α） increases with molar fraction （x） up to x=0.2 and then decreases, the electrical conductivity （α） increases with increasing molar fraction x value. Considering the same fabrication technology of Zn4-xCuxSb3-xBix and Zn4-xCuxSb3 with the same x, the measured thermal diffusivities of Zn4-xCuxSb3 were used to calculate the thermal conductivities of Zn4-xCuxSb3-xBix. A relative enhancement of ZT is attained for Zn3.6Cu0.4Sb3.6Bi0.4, whose ZT is 0.53 at 574 K, about 0.07 higher than that of Zn4Sb3 at the same temperature.