The effect of Anodamine on the corrosion behavior of 1018 mild steel in deionized water: II. Electrochemical Impedance Analysis

Electrochemical Impedance Spectroscopy (EIS) has been used to explore the corrosion and electrochemical behavior of 1018 mild steel (MS) in deaerated, deionized water containing different concentrations of the filming amine inhibitor Anodamine. The Point Defect Model (PDM) was optimized on the EIS data using the newly-developed procedure to study the mitigation mechanism of Anodamine. The optimization results suggest that, as the concentration of Anodamine increases, the pore resistance of the adsorbed inhibitor, the charge transfer resistance, and the Warburg coefficient associated with the transport of redox species through the porous outer layer of the passive film increase, with the latter being the primary cause of inhibition. Accordingly, the hydrophobic layer of adsorbed Anodamine becomes more protective and the inhibitory effect of Anodamine is enhanced as its concentration increases. In addition, within the passive range, increased applied anodic potential enhances the adsorption of Anodamine and hence enhances its inhibitory effect.