Effects of metal cations on corrosion of mild steel in model fresh water

• Corrosion behaviour of steel is different depending on the kind of metal cations in fresh water.
• Metal cations that have large X are incorporated in passive films of the steel.
• The corrosion rate of mild steel can be estimated by using “corrosion inhibitory effect of cations, Y”.s.

The effects of metal cations on corrosion of mild steel in model fresh water were investigated by electrochemical techniques and immersion tests. Analysis of X-ray photoelectron spectroscopy showed that metal cations have large hardness of cations, X, are incorporated in passive films. The electrochemical and immersion results showed that X is not suitable as a corrosion indicator of mild steel. A novel corrosion indicator, “corrosion inhibitory effect of cations Y”, that consists of X and molar volume ratio, ΔV, is proposed, and it is shown that the novel indicator can estimate the corrosion rate of mild steel in fresh water.