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采用真空熔炼/研磨技术制备NaxBi2-xTe2.7Se0.3(x=0,0.02,0.04,0.06)热电材料粉末,利用热压烧结法制备块体样品。通过XRD和SEM对该材料的物相成分和断面形貌进行表征。结果表明:在适当的范围内掺杂Na元素及真空熔炼和热压烧结均不会改变合金的物相,仍为单相Bi2Te2.7Se0.3合金。真空熔炼及热压烧结制备的NaxBi2-xTe2.7Se0.3块体热电材料呈具有一定取向的层状结构、少许的孔隙分布以及结构不均匀性等一系列特征;随Na掺入量的增加,取向程度增大,孔隙数量减少,结构均匀性提高。
The NaxBi2-xTe2.7Se0.3 (x = 0,0.02,0.04,0.06) thermoelectric material powder was prepared by vacuum melting / grinding technology, and the bulk samples were prepared by hot-press sintering method. The phase composition and cross-sectional morphology of the material were characterized by XRD and SEM. The results show that: Na doped in the proper range and vacuum melting and hot pressing sintering will not change the phase of the alloy, still single-phase Bi2Te2.7Se0.3 alloy. NaxBi2-xTe2.7Se0.3 bulk thermoelectric materials prepared by vacuum melting and hot-pressing sintering show a series of features such as layered structure with some orientations, little pore distribution and structural inhomogeneity. With the increase of Na content, The degree of orientation increases, the number of pores decreases, and the structural uniformity improves.