Abstract
The variation in corrosion behavior of steel in neutral solutions caused by the presence of copper, nickel or chromium has been investigated by means of electrochemical methods. Sodium sulfate and sodium chloride aqueous solutions have been chosen as corrosion environments, in order to reveal the anion effect on the corrosion of steels studied.
Results obtained are as follows:
1) The corrosion resistance of steels in neutral solution may be evaluated by the corrosion potential and the anodic polarization curve.
2) In sodium sulfate aqueous solution, the corrosion resistance of steel was not affected by the addition of nickel, chromium or copper in steel, whereas in sodium chloride solution, the addition of nickel or chromium tends to increase the corrosion resistance of steel. This phenomenon seems to be correlated with the formation of compact corrosion products on the surface of the steels embracing these elements.
3) In the early stage of corrosion in sodium chloride solution, corrosion behavior of steel was affected by the auto-reduction of corrosion product.
