分析了稀土元素Pr及其两种添加量对Sn0.7Cu0.05Ni无铅钎料焊点界面组织和性能的影响,并对其影响机制进行了初步探讨.结果表明,Pr元素的加入明显改善了钎料/基板的界面组织形貌,使其更为均匀平坦.Pr元素可通过减小界面反应化学驱动力,缩短反应时间,并与Ni元素产生＂协同作用＂来控制界面反应的进行;稀土元素Pr可通过PrSn3相颗粒的析出对焊点组织起到第二相强化的作用,同时会阻碍晶界或相界迁移以细化晶粒,提高焊点强度和韧性,对钎料焊点抗剪强度的测试验证了该理论.%Effects of rare earth element Pr on the intermetallics（ZMC） between Sn0.7Cu0.05Ni-xPr lead-free solder and Cu substrate were studied in this paper.And the possible influence mechanism was initially introduced.The experimental results showed that the interface morphology was greatly modified and became more uniform and flat due to the addition of Pr,and the effect of 0.05%Pr addition was more remarkable than that of 0.15%Pr.Adding Pr could reduce the driving force and time of the interfacial reaction to restrain excessive IMC growth.It was concluded that there was a synergistic effect on the interfacial reaction between Pr and Ni.The strength and ductility of the solder joint were greatly improved due to the refined microstructure because of the pinning effect on the migration of grain boundaries brought by adding Pr,and precipitation hardening strengthened by PrSn3 particles serving as the precipitated phase.
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