Electrochemical corrosion behaviour of copper under periodic wet–dry cycle condition

The effects of the dry period, temperature and (NH4)2SO4 on the electrochemical corrosion behaviour of copper film in printed circuit board (PCB–Cu) under thin electrolyte layer were investigated by electrochemical noise and electrochemical impedance spectroscopy combining with SEM analyses under various periodic wet–dry cycle conditions. Results showed that the corrosion rate of PCB–Cu decreased at the initial stage then increased, and eventually attained a steady state at the last stage, which could be ascribed to the difference of the protective performance of the formed corrosion products. According to the characteristics of the noise potential, each single wet–dry cycle could be divided into three regions.

• Study of the atmospheric corrosion under various periodic wet–dry cycle conditions.
• Study of the atmospheric corrosion under the different relative humidity conditions.
• The corrosion rate of copper increases with the prolongation of dry period.