Electrochemical Corrosion Characteristics of Q235 Steel and Copper in Simulated Red Soil Solutions with Different pH Values

Corrosion and electrochemical characteristics of Q235 steel and copper in red soil simulated solutions with different pH were compared and studied by polarization curve and electrochemical impedance spectroscopy (EIS) techniques. The results show that the corrosion rate of Q235 steel and copper decreased with increasing pH of solution. In red soil simulation solution, the active dissolution of Fe mainly occurred in the anode of Q235 steel, and the corrosion process was controlled by cathodic reduction reaction. The cathode of copper mainly underwent a depolarization reaction of oxygen, and the corrosion process was controlled by anodic dissolution reaction, and the content of H⁺ in the solution would affect the formation process of corrosion product film. In the simulated soil solutions with pH 4 and 5, the corrosion resistance of copper was not much higher than that of carbon steel, and in the simulated solution with pH 6, the formation of dense corrosion product film on the sample surface significantly reduced the corrosion rate of copper.