Electrochemical Studies on the Corrosion Behavior of Mild Steel in NaCl Aqueous Solutions with Zinc Ions

The corrosion behaviors of mild steel in NaCl aqueous solution with different Zn2+ concentrations have been investigated electrochemically. The immersion potentials were influenced by the presence of Zn2+ and shifted to the positive direction with increasing the Zn2+ concentration in the solutions. Zn2+ suppressed the current density in both cathodic and anodic polarization, and the inhibition effects increased with increasing the Zn2+ concentrations. The electrochemical impedance spectroscopy (EIS) results showed the highest charge transfer resistance in the Zn-rich solution due to the formation of Zn-layer with the steel surface. The Zn-layer thickness increased, and the area of defects in the oxide film on the steel surface decreased with increasing the Zn2+ concentration. Therefore, it was suggested that the corrosion inhibition ability of mild steel in NaCl aqueous solution significantly improved with increasing the concentration of Zn2+ in the solution.