Electrochemical migration behavior of SnAgCuNi solder alloy in a simulated dew condensation environment

This study investigates SnAgCuNi lead-free solder alloys, focusing on the electrochemical migration (ECM) failure mechanism under simulated dew condensation conditions. The corrosion characteristics and ECM resistance of the alloys were systematically evaluated. Electrochemical measurements showed that low Ni additions (0.05-0.10 wt%) shifted the corrosion potential positively, reduced the corrosion current density, and significantly increased the charge transfer resistance, indicating improved passivation behavior. The results indicate that the addition of 0.05-0.10 wt% Ni effectively suppresses the ECM reaction rate, reduces ion concentration within the droplet system, mitigates corrosion of the solder alloy, and consequently enhances the ECM resistance of SAC305. In contrast, increasing the Ni content to 0.25 wt% markedly deteriorates ECM resistance. These findings provide a scientific basis and preventive strategies for addressing potential reliability concerns and the risks of metal corrosion migration in electronic packaging.