Corrosion inhibition performance of three imidazole derivatives on mild steel in 1 M phosphoric acid

The effect of benzimidazole (BI), 2-methyl benzimidazole (2MBI) and 2-aminobenzimidazole (2ABI) on the corrosion of mild steel was evaluated in 1 M phosphoric acid at various concentrations using electrochemical techniques (Electrochemical Impedance Spectroscopy (EIS) and DC polarization). Inhibition of imidazole derivatives was evaluated at concentrations between 5 × 10−2–10−4 M. It was observed that inhibition efficiency increased with increasing inhibitor concentration. Adsorption of imidazole derivatives on the metal surface was investigated to consider basic information on the interaction between the inhibitors and the metal surface. Flory–Huggins adsorption isotherm model showed that each inhibitor replaces 3–5 molecules of water on the metal surface.