Effect of SO42– Concentration on Electrochemical Corrosion Behavior of PCB-Cu under Thin Liquid Film

<p>The electrochemical corrosion behavior of PCB-Cu under thin liquid film was investigated with varying concentrations of SO<sub>4</sub><sup>2–</sup> through polarization curves and electrochemical impedance spectroscopy (EIS). The results indicate that the corrosion process of PCB-Cu was primarily controlled by the reduction of oxygen and the corrosion products. The cathodic current density increased with the concentration improvement of SO<sub>4</sub><sup>2–</sup>. Initially, the corrosion rate was dominated by the cathodic reduction process, however, in later stages of corrosion, the accumulation of surface corrosion products inhibited further corrosion of PCB-Cu.</p>