微合金化低银无铅钎料的性能研究

Properties of microalloyed low-silver lead-free solders

无铅钎料的溶铜性能是影响波峰焊工艺品质和生产效率的重要因素之一。文中在前期研究优选出的Sn-0.5Ag-0.7Cu低银无铅钎料的基础上,系统研究了微量P、Ni合金元素的添加量对钎料溶铜性能和焊接性的影响,观察了界面金属间化合物的生长情况,并将微合金化后的钎料与Sn-3.0Ag-0.5Cu合金进行了焊接性及物理特性对比。结果表明,在0～0.1%的添加量范围内,随着P含量增加,焊接性有所改善,溶铜量呈先升后降的趋势;随着Ni含量的增加,焊接性变差,溶铜量不断降低。推荐的微合金化成分为:添加0.02%的P和0.02%的Ni。这种新型钎料与Sn-3.0Ag-0.5Cu合金相比,焊接性及物理性能接近,但溶铜量降低了69%。

The copper dissolution rate of lead-free solder has strong impacts on both wave soldering quality and production efficiency. Based on the optimized low-silver solder alloy Sn-0.5Ag-0.7Cu from the previous research by authors, the effect of trace amount of P and Ni addition on the copper dissolution rate and solderability were studied. Microstructure of intermetallic compound was analyzed. The solderability and physical properties of micoralloyed low-silver solder and Sn -3.0Ag -0.5Cu were compared. Results show that within the addition range of 0 -0.1%, with the amount of P being increased, solderability keeps improving, while the copper dissolution rate increases at first and then decreases. With the amount of Ni increased, the copper dissolution rate keeps decreasing, while solderability becomes worse. Recommended microalloying compositions are: 0.02% P and 0.02% Ni. Compared with Sn -3.0Ag -0.5Cu, this new alloy has similar solderability and physical properties, while the copper dissolution rate is decreased by 69%.