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

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 beta-Sn and the defects especially at boundaries facilitate Cl- preferential adsorption. After the oxides film deterioration, galvanic effect between Ag3Sn and beta-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. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The corrosion effect of Ag addition on Sn solder is influenced by the formed surface oxide film, where the oxide film on Sn-Ag solder is more susceptible to NaCl electrolyte attack compared to pure Sn solder. Variations in oxide film thickness among Ag3Sn and beta-Sn phases, along with defects at boundaries, facilitate Cl- preferential adsorption. Additionally, galvanic effect between Ag3Sn and beta-Sn contributes to further corrosion after oxide film deterioration.