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分析了不同稀土元素Pr的添加量对Sn0.7Cu0.05Ni无铅钎料润湿性能、焊点力学性能以及钎料显微组织的影响,并对焊点内部组织的演化规律与其性能之间的内在联系进行了初步探讨.研究发现,稀土元素Pr的适宜添加量为0.025%~0.075%,且存在一最佳添加量0.05%.微量稀土元素Pr的加入可显著降低液态钎料的表面张力,改善其润湿性,同时可对晶界迁移产生钉扎作用,细化焊点组织,提高焊点力学性能.过量Pr元素的加入会因其过度氧化及其所引起的应力场综合作用增大等原因导致其活性作用降低.
The effects of different amount of rare earth element Pr on the wettability, mechanical properties of solder joint and microstructure of solder were investigated. And the relationship between the evolution of internal structure of solder joint and its performance The results show that the suitable addition amount of rare earth element Pr is 0.025% ~ 0.075%, and there is an optimal addition amount of 0.05% .The addition of trace rare earth element Pr can significantly reduce the surface tension of liquid solder, Improve its wettability, at the same time can have a pinning effect on the grain boundary migration, refine solder joint structure, improve the mechanical properties of solder joints.Addition of excessive Pr element will be due to its excessive oxidation and the resultant increase of stress field And other reasons lead to reduced activity.