Electrode process characteristics of Q235 carbon steel corroded in the seashore salt soil

The effect of water content on the electrode process of Q235 carbon steel corroded in the seashore salt soil was studied by using electrochemical impedance spectrum (EIS) measurements at ±50 mV polarization potential and open circuit potential with water content of 10%, 20% and 34%. When the water content was 10%, the cathodic process was mainly affected by charge transfer resistance (R_t) and the resistance of bonding layer (R₁), and the bonding layer blocked anodic process more heavily than cathodic process. When the water content was 20% and 34%, the cathodic process was mainly presented as diffusion controlled, and the bonding layer mainly affected the process of anodic dissolution. With the increase of water content, the charge transfer resistance of anodic reaction reduced gradually, while the effect of the cathodic diffusion control became more and more obvious.