Effect of the content of Ni on mechanical properties of Sn0.7Cu solder alloy

摘要

SnCu lead-free solder is regarded as a promising lead-free solder alloy for its good solderability and low cost in the filed of the wave welding.Compared to SnAgCu solder,the mechanical properties of Sn0.7Cu solder alloy are poorer,which badly affect the wide applications of the solder.In the paper a new solder is made by adding trace Ni into Sn0.7Cu to improve the mechanical properties.Results show that the tensile strength and the shear strength of the new solder increase with the increasing of the content of Ni when Ni is less than 0.7 wt%.Compared to the matrix of Sn0.7Cu,the tensile strength and the shear strength are respectively improved by 12% and 54% when the content of Ni is 0.7 wt%.Micro-structure analysis shows that Ni3Sn4 binary alloy is formed by adding trace Ni to SnCu matrix solder alloy,which has the function of dispersion strengthen.This is the main mechanism of improvement of the mechanical properties of the SnCu-Ni solder alloy.