use of Hammett acidity function for the characterization of the corrosion behavior of stainless steel in aqueous and mixed methanol-water media containing acid

The electrochemical behavior of stainless steel [304 and 316] has been investigated in aqueous solutions of hydrochloric acid and in acidic mixed methanol-water solvents. The comparison of the results obtained in different concentrations would be questionable if the main physicochemical properties of the solutions were not vigorously defined. In the case of acidity which is one of the most important parameters for comparison of the corrosion mechanism, the use of the Hammett acidity function, Ho, is more suitable than scale in the organic mixed solvents. This study pointed out that Hammett acidity function, may be a correct measurement of the acid strength of the proton, is the main factor governing the corrosion phenomenon