Effect of Ni on Performances of Sn2.5AgO.7CuO.1RE Solder Alloy and Its CreepProperties of the solder Joints for SMT

KeKe Zhang, YanLi Fan, Yaoli Wang, Yaomin Zhu, Xin Zhang, Yanfu YanSchool of Material Science and Engineering, Henan University of Science and Technology,

No.48 Xiyuan Road, Luoyang,Henan,471003, P.R.ChinaEmail: zhkeke@mail.haust.edu.cn

AbstractWith the development of electronic productions based on

lead-free solder, SnAgCuRE as a special lead-free solderalloy in our country, which possess better microjoiningtechnological property and higher mechanical property, hasbeen the hot-point of the microjoining research field. Toreduce the manufacturing costs of SnAgCuRE lead-freesolder alloy and improve or increase its creep and fatigueproperties of soldered joints, with reference to thecommercial employed Sn3.8AgO.7Cu solder, takingSn2.5AgO.7CuO.iRE lead-free solder alloy with lower Agcontent as a research object, based on the research ofmicrostructure, mechanical and physical performances andwettability of Sn2.5AgO.7CuO. 1REXNi solder alloy withlower Ag content fabricated by vacuum condition in thispaper. And the creep behavior and its rupture life ofSn2.5AgO.7CuO. 1REXNi soldered joints were separately

investigated under constant temperature by a single shear lapcreep specimen with a lmm2 cross sectional area. The resultshows that the performances of Sn2.5AgO.7CuO.iRE solderalloy and its creep properties of the solder joints can beimproved with adding Ni, especially the elongation ofSn2.5AgO.7CuO. lREO.05Ni can be obviously improvedwithout degradation its strength, which is 1.4 times morethan that of the commercial employed Sn3.8AgO.7Cu solderalloy. Accordingly the creep rupture life of its solder joints isthe longest , which is 13.3 times more than that ofSn2.5AgO.7Cu O.iRE, and is far superior to that of thecommercial employed lead-free solder Sn3.8AgO.7Cu.Therefore, Ni amount added to the Sn2.5AgO.7CuO. iREsolder alloy under 0.05%0 is proper. The results are helpfulfor the practical application of Sn2.5AgO.7CuO.iRE lead-free solder.

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