Ag和RE对表面组装用SnAgCuRE无铅钎料显微组织的影响

Effect of Ag and RE on Microstructure of SnAgCuRE Lead-free Solder

采用扫描电镜和能谱分析等检测手段,分别研究了Ag和RE含量对SnAgCuRE系钎料合金显微组织的影响。结果表明,随着Ag和RE含量的增加,SnAgCuRE无铅钎料的显微组织中的共晶组织所占比例增大,钎料合金中富Sn相的组织细化。但Ag含量超过3.2 wt%时,会出现大的板条状Ag3Sn初晶,因此,Ag的最佳添加量在2.0wt%～3.0wt%。当RE添加量达到0.5wt%时,会出现大块的花瓣状和点、条状的CeSn3和LaSn3稀土化合物相,聚集在共晶组织和富Sn相界面处,导致钎料性能下降。

The effects of Ag and RE on the microstructure of SnAgCuRE solder were investigated by scanning electronic microscope and energy spectrum analysis.The results show that with the Ag content increasing,the microstructure of SnAgCuRE solder alloy becomes more even and fine,the proportion of eutectic structure in the solder alloy increases accordingly.But Ag3Sn appears when the content of Ag exceeds 3.2 wt%,so the best addition of Ag is 2.0 wt%～3.0 wt%.Large pieces of CeSn3 and LaSn3 which is harmful to its performance,grow on the interface of eutectic and β-Sn phase,when the content of RE reaches 0.5wt%.