Impact of Cu content on corrosion property of Zn20Sn lead-free solder

New types of alloys Zn20SnxCu were prepared by adding different contents of Cu into Zn20Sn master alloy, using alloying principle, and the effect of Cu content on the corrosion resistant property of Zn20Sn solder alloy was investigated. The results show that when the Cu content was less than 4%, the corrosion potential of Zn20SnxCu solder alloy increased, the corrosion rate reduced gradually, and the corrosion resistance of solder alloy increased with the increase of Cu content. When the Cu content was more than 4%, the corrosion potential of Zn20SnxCu solder alloy reduced, the corrosion rate increased gradually, and the corrosion resistance of solder alloy reduced with the increase of Cu content. The main products on the corrosion surface of Zn20SnxCu were Zn5(OH)₈Cl₂·H₂O and ZnO. Considering the corrosion performance of Zn20SnxCu, the optimized addition amount of Cu is 4%.