Influence of an Imidazoline Quaternary Ammonium Salt on Pitting Corrosion of Carbon Steel in NaNO2₂+NaCl Solution

The effect of an imidazoline quaternary ammonium salt on pitting corrosion of Q235 carbon steel in a NaNO2 + NaCl solution was studied by polarization curves,Mott-Schottky curves,XPS and ESTM methods.The results showed that the imidazoline quaternary ammonium salt could accelerate the formation of the passive film on carbon steel surface in a NaNO2+NaCl solution and decrease the passive current;the imidazoline quaternary ammonium salt absorbed on carbon steel surface could also decrease the donor concentration in passive films and improve the film′s corrosion resistance;though imidazoline quaternary ammonium salt had no obvious influence on pitting potential,it was helpful for repassivation of stable pit with a proper quantity (e.g.40 mg/L).