A perspective on effect by Ag addition to corrosion evolution of Pb-free Sn solder

Abstract The corrosion effect by Ag addition to Sn solder has been explored with consideration of the formed surface oxides film. Results indicate that the oxides film on Sn-Ag solder maintains a much shorter duration to NaCl electrolyte attack than that on pure Sn solder. The film thickness variation among phases of Ag3Sn and β-Sn and the defects especially at boundaries facilitate Cl− preferential adsorption. After the oxides film deterioration, galvanic effect between Ag3Sn and β-Sn comes into play for further corrosion. This observed evolution behavior provides a practical perspective to corrosion of Ag-alloyed Sn solder with an oxides film covering.