电场激活合成Mg_2Si的热电性能研究

Thermoelectric Properties of Mg_2Si Synthesized by Field-activation

用Mg粉和Si粉通过电场激活加压辅助法(Field-activated and Pressure-assisted Synthesis,FAPAS),在1073 K、50 MPa条件下快速实现了Mg2Si块体热电材料的一步法合成与致密化;合成过程反应物反应完全,产物的XRD曲线的Mg2Si峰型尖锐,占产物含量的99.5%。合成样品的Seebeck系数、电导率、功率因子分别在562K、773 K、600 K时达到最大值,分别为445μVK-1、54.4 Scm-1、4.35 W/cmK2。通过对比多种方法合成的Mg2Si热电材料的热电性能发现,FAPASA样品的功率因子比其它方法具有明显的优势。

By using Mg and Si powders as raw material, hulk thermoelectric material Mg2Si was synthesized and compected speedily in one step by field-activation and pressure assisted synthesis at 1073 K, 50 MPa for 15 min. It is found that Mg2 Si peak is the only sharp peak and there is no residual Si or Mg peak in the XRD pattern of FAPAS sample. The content of Mg2Si is about 99.5%. The optimal value of Seebeck coefficient α and electrical conductivity α of the FAPAS samples are 445 μVK^-1 and 54.4 Scm^-1 ,which are obtained at the temperatures of 562 K and 773 K respectively. The highest power factor of 4.35 × 10^-6 W/cmK^2 at book, is obtained from the calculation of the Seebeck coefficient and electrical conductivity of sample. Compared with other synthesis methods, the FAPAS sample can achieve a higher power factor.