微量铬添加与快速凝固对Sn-9Zn合金钎料及钎料/铜焊点界面特性的影响

Effects of Trace Chromium Addition and Rapid Solidification on Characteristics of Sn-9Zn Alloy Solder and Solder/Copper Joint Interface

通过真空熔炼制备Sn-9Zn和Sn-9Zn-0.1Cr(质量分数/%)合金钎料,并利用单辊法得到快速凝固态Sn-9Zn-0.1Cr合金钎料,研究了微量铬添加和快速凝固对钎料显微组织、润湿性能、耐腐蚀性能,以及钎料/铜焊点界面金属间化合物(IMC)层在85℃时效过程中生长动力学的影响。结果表明:添加质量分数0.1%铬能够抑制Sn-9Zn合金钎料中富锌相的聚集并细化共晶组织,提高合金钎料的最大润湿力并缩短润湿时间,抑制钎料/铜焊点界面IMC层的生成以及在时效过程中的过度生长;快速凝固态Sn-9Zn-0.1Cr合金钎料中富锌相呈颗粒状弥散分布于β-Sn枝晶中,组织更加细小均匀,耐腐蚀性能显著改善,但界面IMC层在85℃时效过程中的生长速率相比于熔炼态合金钎料略有增大。

Sn-9Zn and Sn-9Zn-0.1Cr(mass fraction/%) alloy solders were prepared by vacuum melting, and then the rapidly solidified Sn-9Zn-0.1Cr alloy solder was obtained by a single roll method. The effects of the trace chromium addition and rapid solidification on the solder microstructure, wetting properties and corrosion resistance, as well as on the growth kinetics of intermetallic compound(IMC) layers at the solder/copper joint interface during aging at 85 ℃, were investigated. The results show that the addition of 0.1 wt% chromium could inhibit the aggregation of zinc-rich phases and refine the eutectic structure in the Sn-9Zn alloy solder, increase the maximum wetting force and shorten the wetting time of the alloy solder, and inhibit the formation and the overgrowth during aging of the interfacial IMC layer of the solder/copper joint. The zinc-rich phase in the rapidly solidified Sn-9Zn-0.1Cr alloy solder was granular and dispersed in β-Sn dendrites, the structure was finer and more uniform, and the corrosion resistant was significantly improved;but the growth rate of the interfacial IMC layer during aging at 85 ℃ slightly increased compared with that of the as-smelted alloy solder.