论文部分内容阅读
在微波作用下利用MgH_2、纳米Si粉、Sn粉和Bi粉进行固相反应,结合电场激活压力辅助合成法(FAPAS)制备了高纯Bi掺杂的Mg_2Si_(1-x)Sn_x(0.4≤x≤0.6)基固溶体热电材料,并对其微观结构和热电性能进行了表征。结果表明,MgH_2替代传统原料Mg粉显著降低了固相反应温度且防止了Mg的挥发和氧化,同时微波快速低温加热有效抑制晶粒长大,可获得平均晶粒尺寸为200 nm的高纯产物。在300~750 K的温度区间对样品热电性能进行测试。结果表明,细小的片层固溶体组织和Bi的掺杂有效降低了样品热导率,同时改善了其电性能,在600 K时,含1.5%Bi(原子分数)的Mg_2Si_(0.4/0Sn_(0.6)热电材料具有最大ZT值0.91。
Under the action of microwaves, MgH_2, nano-Si powder, Sn powder and Bi powder were used for solid-state reaction. The high purity Bi-doped Mg_2Si_ (1-x) Sn_x (0.4≤x ≤0.6) based solid solution thermoelectric material, and its microstructure and thermoelectric properties were characterized. The results showed that MgH 2 instead of the traditional Mg powder significantly reduced the solid-phase reaction temperature and prevented the volatilization and oxidation of Mg. Simultaneously, the microwave heating at low temperature effectively restrained the grain growth and obtained the pure product with the average grain size of 200 nm . The thermoelectric properties of the samples were tested in the temperature range of 300 ~ 750K. The results show that the doping of thin solid solution and Bi effectively reduces the thermal conductivity and improves the electrical properties of the samples. At 600 K, Mg_2Si_ (0.4 / 0Sn_ (0.6) ) The thermoelectric material has a maximum ZT value of 0.91.