采用FAPAS法制备掺杂Y的Mg_2Si及其热电性能

Y-doped Mg_2Si Prepared by Field-Activated and Pressure-Assisted Reactive Synthesis

本文通过电场激活压力辅助法(FAPAS)制备了Mg2Si和掺杂稀土元素Y的Mg2Si基热电材料,并对不同掺杂量下的试样进行物相分析及热电性能的比较。用该方法制备的两种试样均具有组织均匀,晶粒细小的结构。Y掺杂试样的电性能得到明显改善,在288-580K温度范围内,掺杂2000ppmY试样的seebeck系数随着温度的升高而增大,其绝对值大于未掺杂试样的seebeck系数。在438K时,其电导率是未掺杂试样电导率的1.67倍。此外,Y掺杂试样的热导率也明显降低了。因此,掺杂试样的热电综合性能得到了提高,其ZT值在408K达到未掺杂试样的2.23倍。

Mg2Si and Y-doped Mg2Si were prepared by the field-activated and pressure assisted synthesis（FAPAS）process from elemental powders.The products have uniform and relatively fine-grained microstructure which can ensure good thermal and electrical performances.The Seebeck coefficient of Y-doped Mg2Si（2000ppmY-doped sample）increases in the temperature range of 288-580K and is higher than that of non-doped Mg2Si.And the electric conductivity was enhanced as well,which reached up to 1.67 times of non-doped Mg2Si at 438K.the figure of merit-ZT was improved obviously,which reached up to 2.23 times of non-doped Mg2Si at about 408K.