中文摘要：

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。

英文摘要：

The method of vacuum-melting/grinding was used to prepare Naxi2-xTe2.7Se0.3 （x=0, 0.02, 0.04, 0.06） thermoelectric material powders, and the hot-pressing sintering method was employed to consolidate the powders into bulk materials. The phase composition and morphologies of the materials were characterized by XRD and SEM. The results show that Na, Bi, Te and Se elemental powders are alloyed to be a single-phase of Bi2Te2.7Se0.3 after vacuum-melting/grinding. There is no phase transition reaction within the certain content of Na doping during hot-pressing sintering process. The surface morphologies of NaxBi2-xTe2.7Se0.3 thermoelectric materials prepared by vacuum melting and hot-pressing sintering present layer structure with definite orientation, a distribution of some pores and the inhomogeneity of the structure; with the increase of Na doping concentration, the degree of orientation increases, the amount of pores decreases, and the uniformity of the structure improves.