Effects of Ag contents in Sn-xAg lead-free solders on microstructure,corrosion behavior and interfacial reaction with Cu substrate  

Sn-xAg无铅焊料中Ag含量对其显微组织、腐蚀行为和与Cu基体界面反应的影响

作　　者：Phacharaphon TUNTHAWIROON Kannachai KANLAYASIRI 

机构地区：[1]Department of Industrial Engineering, Faculty of Engineering,King Mongkut’s Institute of Technology Ladkrabang

出　　处：《Transactions of Nonferrous Metals Society of China》2019年第8期1696-1704,共9页中国有色金属学报（英文版）

摘　　要：The effects of Ag on the microstructure and corrosion behavior of pre-soldering Sn-xAg lead-free solders,and on the formation of intermetallic layer of the solders with Cu substrate were investigated.The Ag contents(x)were 0,3.0,3.5,4.0,and5.0 wt.%.The Ag content played a role in the morphology of Ag3 Sn phase in the solders.The microstructure analysis showed that theβ-Sn phase was surrounded by eutectic networks in the 3.0 Ag and 3.5 Ag solders and large plate-like Ag3 Sn formed in the 4.0 Ag and5.0 Ag solders.Nonetheless,the Ag content slightly impacted the corrosion behavior of the as-cast solders as characterized using potentiodynamic polarization test.After soldering,only a single layer of a Cu6 Sn5 intermetallic compound formed at the Sn-xAg/Cu interface.By comparison,the Cu6 Sn5 intermetallic layer of the Ag-doped solders was thinner than that of the 0Ag solder.The fine Ag3 Sn particles in the eutectic networks precipitating in the 3.0 Ag and 3.5 Ag solders effectively hindered the growth of Cu6 Sn5 grains compared to large plate-like Ag3 Sn in the 4.0 and 5.0Ag solders.研究不同Ag含量(0、3.0%、3.5%、4.0%和5.0%,质量分数)对预焊Sn-xAg无铅焊料显微组织和腐蚀行为的影响,以及对焊料与铜基体间形成金属间化合物界面层的影响。Ag含量对焊料中Ag3Sn相的形貌有一定的影响。显微组织分析结果表明,在3.0Ag和3.5Ag焊料中,β-Sn相被共晶组织网络所包围;在4.0Ag和5.0Ag焊料中,形成大的片状Ag3Sn相。但是,动电位极化曲线测试结果显示,Ag含量对铸态焊料腐蚀行为的影响甚微。与铜基体焊接后,在Sn-xAg/Cu界面处仅形成单层的Cu6Sn5金属间化合物。与未掺Ag的焊料相比,掺Ag的焊料与基体的界面中形成的Cu6Sn5金属间化合物层更薄。与4.0Ag和5.0Ag焊料中形成的大片状Ag3Sn相比,在3.0Ag和3.5Ag焊料中析出的共晶网络中细小的Ag3Sn颗粒沉淀,能更有效地抑制Cu6Sn5晶粒的生长。

关 键 词：Sn-Ag lead-free solders MICROSTRUCTURE Ag_(3)Sn intermetallic phase corrosion behavior Cu_(6)Sn_(5) intermetallic layer wettability 

分 类 号：TG42[金属学及工艺—焊接]