Effects of pH and Cl− concentration on corrosion behavior of the galvanized steel in simulated rust layer solution

Effects of pH and Cl− concentration on the corrosion behavior of galvanized steel in simulated rust layer (SRL) solution have been investigated using measurements of weight loss, electrochemical impedance spectroscopy (EIS), linear polarization combined with cyclic polarization experiment. In neutral SRL solutions, pitting corrosion occurred on the galvanized steel simultaneously. However, exposure to high alkaline solutions resulted in passivation. Results revealed that the galvanized steel in SRL solution was susceptible to pitting corrosion in all chloride solution of concentration ranging between 0.1 and 0.6 M.

► Galvanized steel corrosion behavior was studied in simulated rust layer solution.
► Rust layer absorbed on the electrode was gradually damaged by Cl−.
► Increasing Cl− concentration will increase corrosion rate of galvanized steel.
► Galvanized steel is passivated in high alkaline simulated rust layer solution.
► ZnO is responsible to the high resistance of coating in high alkaline solution.