摘要
Bi2Te3基热电材料需与电极Cu连接构成热电模块。采用无铅钎料Sn—Bi及钎剂实现了大气环境中分别直接钎焊P型（Bi，Sb）2Te3与无氧Cu和n型Bi2（Te，Se）3与无氧Cu。观察了接头的组织及Sn，Cu，Bi元素在接头处的线分布和面分布。通过研究表明，Sn元素与p型（Bi，Sb）2Te3的反应比与n型Bi2（Te，Se）3剧烈，在（Bi，Sb）2Te3与Sn—Bi界面处形成了5～7μm的Sn反应层；Cu元素在Cu／Sn—Bi界面处也形成几微米的反应层；温度增加，两种反应的程度均有增加趋势。利用Gleeble1500D试验机测试了两种类型接头的抗剪强度，结果表明，（Bi，Sb）2Te3／Sn—Bi／Cu接头平均抗剪强度为5．1MPa，Bi2（Te，Se）3／Sn—Bi／Cu接头则为4．4MPa，（Bi，Sb）2Te3／Sn—Bi／Cu接头强度分散性高于Bi2（Te，Se）3／Sn-Bi／Cu接头。接头主要断裂于反应层，反应层的成分、组织和厚度是影响接头强度的关键因素。
Bi_2Te_3-based thermoelectric materials were joined with electrode Cu to constitute thermoelectric modules.The p-type(Bi,Sb)_2Te_3with Cu and n-type Bi_2(Te,Se)_3 with Cu were directly soldered in atmosphere condition with Sn-Bi lead free filler metal and soldering flux.The microstructures of the joints and the distributions of the alloying elements were investigated.The results indicated that Sn of the filler metal reacted with p-type(Bi,Sb)_2Te_3 more severely than with n-type Bi_2(Te,Se)_3,and 5~7μm Sn-Te reactive layer formed between(Bi,Sb)_2Te_3 and Sn-Bi filler metal.A reactive layer of few microns in thickness also existed between Cu and filler metal.The reactive layers became thicker with temperature.The shear test results showed that the average shear strength of(Bi,Sb)_2Te_3/Sn-Bi/Cu joint was 5.1 MPa,while that of Bi_2(Te,Se)_3/Sn-Bi/Cu is 4.4 MPa.The fracture position almost was located in the reactive layer between thermoelectric material and filler metal.The composition,microstructure and thickness of the reactive layer were the key factors.
出处
《焊接》
北大核心
2013年第4期9-13,69,共5页
Welding & Joining
基金
新型钎焊材料与技术国家重点实验室开放课题(SKLABFMT201101)
