The effect of alkaline earth additions on the physical property and the corrosion behavior of Sn-0.7Cu-0.075Al solder alloy

In this study, Sn-0.7Cu-0.075Al alloy (SCA alloy for short) was prepared by ball milling and vacuum melting. The effects of adding Sr and Ca on the microstructure, mechanical properties, physical properties, and electrochemical corrosion properties of SCA alloy were studied. The results show that the content of Cu6Sn5/β-Sn eutectic phase in the microstructure of SCA alloy decreases with the addition of Sr and Ca, and oxide impurity appears in the microstructure of the alloy. The addition of Sr and Ca decreased the electrical conductivity, microhardness, and tensile strength of SCA alloy. The wettability of SCA alloy increases first and then decreases with the addition of Sr and Ca. The addition of Sr and Ca resulted in the formation of a dense corrosion product film with good adhesion during the corrosion process of SCA alloy, which reduced the passivation current density (IP) of the alloy and effectively improved the passivation performance of SCA alloy.