Sn-9Zn-xAg无铅钎料润湿性能及焊点力学性能

Wettability of Sn-9Zn-xAg lead-free solder and mechanical properties of soldered joints

研究了合金元素Ag的添加量对Sn-9Zn无铅钎料润湿性能及其焊点力学性能的影响.结果表明,当Ag元素的添加量(质量分数)为0.3%时,钎料具有最好的润湿性能,焊点的力学性能最佳,焊接接头的断口形貌显示钎料与铜基板接头断口处有明显的韧窝,是典型的韧性断裂;当Ag元素的添加量(质量分数)为0.5%～1.0%时,钎料的润湿性能下降,当Ag元素的添加量(质量分数)增加到1.0%时,焊点的力学性能有所下降,在断口的韧窝底部有大颗的Cu-Zn,Ag-Zn金属间化合物.因此,Sn-9Zn无铅钎料中合金元素Ag的最佳添加量(质量分数)为0.3%.

The effects of Ag on the wettability of Sn-9Zn lead-free solder and the mechanical properties of soldered joints are investigated respectively.The results indicate that when the content of Ag is 0.3 wt.%,the solder gets the best wettability;when the content of Ag is from 0.5 wt.% to 1 wt.%,the wettability decreases.The best mechanical property of soldered joint is obtained when the content of Ag is 0.3 wt.%.Moreover,the fracture micrographs show that plenty of dimples are found on the Sn-9Zn-0.3Ag soldered joints fractures.When the content of Ag is 1 wt.%,some Cu-Zn and Ag-Zn intermetallic compounds appear on the bottom of dimples,and the mechanical property of the soldered joint decreases.In general,the optimum additive amount of Ag in Sn-9Zn solder is about 0.3 wt.%.