(上海交通大学 材料科学与工程学院
教育部高温材料及测试开放实验室， 上海 200030)
摘 要: 在不同冷却速度下制备几种不同成分的多元AgPbmSbTem+2（m=10、 14、 18）化合物并进行退火处理。 粉末X射线衍射结果表明， AgPbmSbTem+2具有与PbTe相同的面心立方结构。 微观组织分析表明， 自熔融状态快速冷却制备的化合物中存在严重的成分偏析， 晶界处有富Ag、 Sb相存在； 缓慢冷却试样中偏聚相较少； 退火处理后， 试样中的偏聚相消失。制备得到的AgPbmSbTe2+m化合物具有典型的枝晶结构。用内标法精确测定AgPbmSbTem+2的晶格常数，晶格常数随m值增大而单调增加； 减少化合物中的Ag含量，晶格常数增大。
关键字: PbTe； 热电材料； 晶格常数； 微观组织
Ag, Sb-alloyed PbTe
（Key Laboratory of the Ministry of Education for
High Temperature Materials and Testing,
School of Materials Science and Engineering,
Shanghai Jiao Tong University, Shanghai 200030, China）
Abstract: A few multicomponent AgPbmSbTem+2 compounds with different compositions were synthesized under different cooling rates and then annealed. The powder X-ray diffraction shows that AgPbmSbTem+2 has the same crystal structure(fcc) as PbTe. The microstructure analysis indicates that severe segregation occurs in the compounds prepared by melt-quenching. The Ag-Sb-rich phase can be observed at the grain boundaries. In contrast, the compounds prepared by slow-cooling have little segregation. After annealed, this segregated phase disappears. The AgPbmSbTem+2 matrix displays a dendrite microstructure. The accurate lattice parameters were measured and calculated by the interpolation method. It is found that the lattice parameters vary monotonously with m and increase with reducing content of Ag.
Key words: PbTe; thermoelectric material; lattice constant; microstructure
