A second-harmonic generation study of a corrosion inhibitor on a mild steel electrode

Second-harmonic generation at surfaces was used to study the adsorption kinetics of a model corrosion inhibitor, oleic imidazoline, onto the surface of a mild steel electrode. It was found that positive polarization relative to the uninhibited rest potential of the electrode, in deaerated salt solution, increased the rate at which the oleic imidazoline adsorbs onto the surface. Negative polarization increased the rate of desorption from the surface. These results show that oleic imidazoline will stick preferentially to anodic sites on a corroding mild steel electrode and this is the mechanism that leads to build-up of the monolayer of oleic imidazoline on the surface.