添加Bi和P对Sn-0.7Cu无铅钎料合金性能的影响

Effects of Bi and P Addition on the Properties of Sn-0.7Cu Lead-free Solder Alloy

研究了添加Bi和P对Sn-0.7Cu无铅钎料合金熔点、显微组织、在Cu上的润湿性、导电率、硬度以及蠕变抗力等性能的影响。实验结果显示,随Bi含量增加,Sn-0.7Cu合金的熔点、导电率略有降低,润湿性、抗蠕变性能和维氏硬度均提高;此外,在添加Bi的基础上加P元素,能进一步降低Sn-0.7Cu-Bi合金的熔点,提高合金的导电率和润湿能力,但合金硬度略有下降;Sn-0.7Cu-1Bi-0.05P钎料合金的抗蠕变性优于Sn-0.7Cu-1Bi,Sn-0.7Cu-3Bi-0.05P钎料合金的抗蠕变性则劣于Sn-0.7Cu-3Bi。金相显微组织观察表明,单独加Bi能细化Sn-0.7Cu合金中的Cu6Sn5金属间化合物相;P的加入使Sn-0.7Cu-1Bi合金中的β-Sn枝晶尺寸变小,且Cu6Sn5相呈规则网络状分布于枝晶间隙;而在Sn-0.7Cu-3Bi合金中加P则粗化了Cu6Sn5相,并使IMC呈无规则分布。

Effects of Bi and P addition on the wettability between Sn-0. 7Cu solder alloy and Cu, and on the melting point, electrical conductivity, hardness, creep resistance and microstructure of Sn-0. 7Cu solder alloy were studied. The results revealed that the wettability, creep resistance and Vickers hardness of Sn-0. 7Cu solder were enhanced with the increasing of Bi, while the melting point and the electrical conductivity were decreased slightly. In addition, the melting point and hardness of the solder could be reduced and the electrical conductivity and the wettability to Cu could be enhanced as P was added into Sn-0. 7Cu-Bi. The creep resistance of Sn-0. 7Cu-1Bi-0. 05P solder alloy was superior to that of Sn-0. 7Cu-1Bi, but for Sn-0. 7Cu-3Bi, the result was reversed. It was observed from the microstructure of Sn-0. 7Cu-based solders that Cu6Sn5 phase was refined by the addition of Bi. The P addition into Sn- 0. 7Cu-1Bi made the grain size of β-Sn dendrites smaller and the Cu6 Sn5 phase network become well ordered. However, it was found that the Cu6 Sn5 phase was coarsened and its distribution exhibited irregular in Sn matrix by the addition of P into Sn-0. 7Cu-3Bi.