(上海交通大學 材料科學與工程學院
教育部高溫材料及測試開放實驗室， 上海 200030)
摘 要: 在不同冷卻速度下制備幾種不同成分的多元AgPbmSbTem+2（m=10、 14、 18）化合物并進行退火處理。 粉末X射線衍射結(jié)果表明， AgPbmSbTem+2具有與PbTe相同的面心立方結(jié)構(gòu)。 微觀組織分析表明， 自熔融狀態(tài)快速冷卻制備的化合物中存在嚴重的成分偏析， 晶界處有富Ag、 Sb相存在； 緩慢冷卻試樣中偏聚相較少； 退火處理后， 試樣中的偏聚相消失。制備得到的AgPbmSbTe2+m化合物具有典型的枝晶結(jié)構(gòu)。用內(nèi)標法精確測定AgPbmSbTem+2的晶格常數(shù)，晶格常數(shù)隨m值增大而單調(diào)增加； 減少化合物中的Ag含量，晶格常數(shù)增大。
關(guān)鍵字: PbTe； 熱電材料； 晶格常數(shù)； 微觀組織
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
