Effects of metal cations on mild steel corrosion in 10 mM Cl− aqueous solution

Highlights: • Different surface morphologies were observed by SEM after immersion in the different solutions with metal cations. • XPS and EDS analysis results showed that only Zn remains on the specimen among other experimental metal cations after immersion in the solutions. • Zn²⁺ was incorporated in the oxide films by making a strong bond with the film in the 10 mM Cl⁻ aqueous solution. • Zn²⁺ forms a protective metal cation layer with the oxide film thus inhibits the corrosion reactions, and consequently lowers the corrosion rate. - Abstract: The influences of metal cations on the corrosion of mild steel in 10 mM Cl⁻ aqueous solutions were investigated by electrochemical techniques and immersion tests. Immersion tests and electrochemical impedance spectroscopy (EIS) results showed that Zn²⁺ has a significant effect on corrosion inhibition. Surface morphological inspection also showed the smooth surface of specimen immersed in Zn²⁺ containing solution. Analysis of X-ray photoelectron spectroscopy showed that Zn²⁺ was incorporated in the oxide films by making a strong bond. It is supposed that Zn²⁺ forms a very effective shielding film which can inhibit the electrochemical reactions, and consequently lowers the corrosion rate.