(南昌大学 材料科学与工程学院, 南昌 330031)
摘 要: 通过差热分析（DTA）, 研究Sn-xZn合金（x=2.5~9）的非平衡熔化性能, 发现在加热速度为5 ℃/min 时, Sn-6.5Zn与Sn-9Zn的熔化特性相同；通过浸润法和铺展法表征Sn-xZn合金在Cu基材表面上的润湿性。结果表明： Sn-6.5Zn在Cu基材表面上的润湿性优于Sn-9Zn。 研究速率为10-3 s-1和10-1 s-1时Sn-xZn的拉伸性能, 结果发现： Sn-6.5Zn的抗拉强度与Sn-9Zn的相当, 而延伸率高于Sn-9Zn。以搭接焊及界面剪切实验研究Sn-xZn/Cu焊点界面强度, 发现焊点界面剪切强度随x的增加而提高, 在x≥6.5时趋于稳定； x=6.5时剪切力最大, 表明Sn-6.5Zn在Sn-Zn系中具有最好的钎焊工艺性能。
关键字: Sn-Zn合金； 无铅焊料； 润湿性； 抗拉强度；延伸率； 焊点强度
（School of Materials Science and Engineering,
Nanchang University, Nanchang 330031, China）
Abstract: The non-equilibrium melting behaviors of Sn-xZn alloys (x=2.5-9) were examined by differential thermal analysis(DTA). The results show that at a heating rate of 5 ℃/min, Sn-6.5Zn behaves in the same way as the eutectic Sn-9Zn in melting. The wettability of Sn-xZn alloys on the surface of Cu base material was characterized with dipping and spreading tests, and the results show that Sn-6.5Zn alloy has significantly better wettability on the surface of Cu base material than Sn-9Zn alloy. The tensile tests at strain rates of 10-3 s -1 and 10-1 s-1 show that Sn-6.5Zn alloy has equivalent tensile strength as Zn-9Zn alloy, and better ductility as Sn-9Zn alloy. The strength of Sn-xZn/Cu lap joints increases as x increases, and levels off when x≥6.5. The maximum shear force of Sn-6.5Zn/Cu is the largest of all Sn-xZn/Cu joints, which indicates that Sn-6.5Zn alloy has the best solderability of Sn-Zn alloys investigated.
Key words: Sn-Zn alloys; lead-free solder; wettability; tensile strength; elongation; joint strength
