The effect of Anodamine on the corrosion behavior of 1018 mild steel in deionized water:I. Immersion and polarization tests

• Preformed layer of absorbed Anodamine can mitigate the corrosion of mild steel.
• Increasing Anodamine level can enhance the passivation of mild steel in DI water.
• Gradual anodic potentiodynamic polarization enhances adsorption of Anodamine.
• Cathodic polarization induces the desorption of Anodamine.
• Corrosion is catalyzed once depassivation occurs in the presence of the inhibitor.

The inhibitory effects of Anodamine on the corrosion behavior of 1018 Mild Steel (MS) in deionized water were investigated using immersion tests and electrochemical methods. It is found that the corrosion of 1018 MS is significantly mitigated when the concentration of Anodamine is as high as 100 ppm. The hydrophobic layer of absorbed inhibitor preformed in solution containing 100 ppm Anodamine is still sufficiently resilient to mitigate the corrosion of MS when the concentration of Anodamine is gradually decreased to 0 ppm. With increasing concentration of Anodamine, the passive range of MS in deionized water is gradually expanded. However, after depassivation by anodic polarization, pitting occurs and the current density increases rapidly. The adsorption of Anodamine can be enhanced by gradual anodic potentiodynamic polarization whereas cathodic polarization induces desorption. Once depassivation had occurred, Anodamine was not re-adsorbed onto the corroding sample surface and the corrosion process was even catalyzed in the presence of Anodamine.