The mechanism of the corrosion inhibition of carbon steel in neutral medium by chromate and nickel ions

The electrochemical behaviour of carbon steel in 3.5% NaCl solutions containing dichromate and nickel ions, has been investigated by anodic polarization curves and gravimetric measurements. The presence of Cr/Ni ions, as low as 0.005 M, in the chloride medium has been observed in this study to inhibit the aggressiveness of the corrodent for the carbon steel by a noble shift of the corrosion potential, E corr, of the metal. Interface and interphase inhibition mechanisms are proposed to suggest explanations for the inhibiting experimental observations of these ions in the corrosion of carbon steel.