Sn-6Bi-2Ag(Cu,Sb)无铅钎料合金微观组织分析

Microstructures of Sn-6Bi-2Ag(Cu,Sb) lead-free solder alloys

利用差示扫描量热计 (DSC)测定了Sn 6Bi 2Ag ,Sn 6Bi 2Ag 0 .5Cu ,Sn 6Bi 2Ag 2 .5Sb三种新无铅钎料合金的熔化温度。结果表明 ,少量Cu的加入能降低Sn Bi Ag系无铅钎料合金的熔化温度 ,而Sb的加入使合金的熔化温度升高。利用光学显微镜 (OM )、扫描电子显微镜 (SEM )、能谱分析 (EDX)对合金的微观组织进行了分析与比较 ,钎料合金的微观组织与冷却条件和合金元素的含量有关 ,Sb的加入使析出相的尺寸细化。硬度测定表明Sn Bi Ag(Cu ,Sb)无铅钎料合金的硬度远大于纯Sn的硬度 ,加入少量的Cu(0 .5 % ) ,Sb(2 .5 % )对Sn Bi

The melting ranges of the three new lead-free solder alloys Sn-6Bi-2Ag, Sn-6Bi-2Ag-0.5Cu, Sn-6Bi-2Ag-2.5Sb were measured by a differential scanning calorimeter (DSC). The addition of Cu decreases the melting range of solder alloy, while that of Sb increases the melting range. Their microstructures were revealed by using optical microscope (OM), scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX). The microstructures of solder alloys strongly depend on the cooling condition and the alloying addition, Sb dissolves in Sn and decreases the precipitation phase sizes of Bi and Ag 3Sn. It is shown that the additions of Cu and Sb have a weak effect on the microhardness of the solder alloys.