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采用真空熔炼制备了三元Bi2Te2.7Se0.3合金材料,再利用热压烧结法烧结成型,用XRD和SEM对材料物相成分和形貌进行了表征。结果表明,Bi、Te、Se单质粉末经真空熔炼形成了单相Bi2Te2.7Se0.3合金,热压烧结过程中未发生相变反应,热压烧结后仍为单相Bi2Te2.7Se0.3;热压烧结后热电材料在微观结构上存在各向异性,沿垂直于压力方向产生优化取向,沿(0001)面的解理断裂局限在单颗晶粒的尺寸范围,这预示着能够在增强材料力学性能的同时提高热电性能。
The ternary Bi2Te2.7Se0.3 alloy was prepared by vacuum melting and then sintered by hot-pressing sintering. The phase composition and morphology of the material were characterized by XRD and SEM. The results showed that the single-phase Bi2Te2.7Se0.3 alloy was formed by vacuum melting of the single-component powders of Bi, Te and Se. No phase change reaction took place during the hot-pressing sintering and remained single-phase Bi2Te2.7Se0.3 after hot-pressing sintering. The microstructural anisotropy of the thermoelectric material after pressure sintering results in an optimized orientation perpendicular to the pressure direction and the cleavage fracture along the (0001) plane is confined to the single grain size range, Performance while improving thermoelectric performance.