稀土Er对Sn-3.0Ag-0.5Cu无铅焊料合金组织与性能的影响

Effect of Er on microstructure and properties of Sn-3.0Ag-0.5Cu lead-free solder alloy

研究稀土Er含量对Sn-3.0Ag-0.5Cu无铅焊料合金显微组织以及性能的影响。结果表明:当Er含量为0.05%～0.50%(质量分数)时,对该无铅焊料合金的导电性和腐蚀性影响不大,但使熔化区间温度降低;当Er含量为0.05%时,焊点剪切强度最高;当Er含量为0.10%时,焊料铺展面积最大,焊料润湿性有所改善,同时焊料的拉伸强度达到最高;当Er含量为0.25%时,伸长率最大。随着Er含量的增加,该焊料合金的组织由树枝晶向等轴晶转变,且组织逐渐细化。Er的较佳添加量为0.05%～0.25%。

Trace rare earth element Er was added into Sn-3.0Ag-0.5Cu solder to investigate the effect of rare earth on the microstructure and mechanical properties of SnAgCu solder. The results show that, when Er content（mass fraction） is within 0.05%-0.50%, the Er has a slight effect on the resistivity and corrosion, and lowers the melting range. When Er content is 0.05%, the shear strength is the highest. When Er content is 0.10%, the spreading area is the biggest and the tensile strength is the highest. When Er content is 0.25%, the elongation is the highest. With the increase of Er content, the microstructure of the solder changes from fir-tree crystal to equiaxed crystal and is refined. And the suitable content of Er is within 0.05%-0.25%.