The effects of Cl− ion concentration and relative humidity on atmospheric corrosion behaviour of PCB-Cu under adsorbed thin electrolyte layer

The effects of Cl− ion concentration and relative humidity on atmospheric corrosion behaviour of PCB-Cu under adsorbed thin electrolyte layer were investigated by cathodic polarization curves and electrochemical impedance spectroscopy. Results indicated that the cathodic process of PCB-Cu corrosion was dominated by the reduction of oxygen and corrosion products. The cathodic current density increased with increasing relative humidity and Cl− ion concentration. The corrosion rate was initially dominated by oxygen reduction, but at the later stage of corrosion, the anodic process began to affect the corrosion rate due to the accumulation of corrosion products.

Research highlights
► Design a new thin layer cell.
► In situ study on atmospheric corrosion under adsorbed thin electrolyte layer.
► Study on the effect of relative humidity on corrosion of copper film.
► Study on the effect of Cl− ion concentration on corrosion of copper film.