INFLUENCE OF ANIONS ON THE PERFORMANCE OF ISOMERS OF AMINOBENZOIC ACID ON THE CORROSION INHIBITION AND HYDROGEN PERMEATION THROUGH MILD-STEEL IN ACIDIC SOLUTIONS

The influence of aminobenzoic acids on the corrosion and hydrogen perm eation through mild steel in 1 M HCl and 0.5 M H2SO4 has been studied using weight loss and gasometric measurements and various electrochemi cal techniques, All the three isomers of aminobenzoic acid inhibit the corrosion of mild steel both in HCl and H2SO4 in the order ortho > me ta > para, It is observed that the inhibition is greater in HCl than i n H2SO4. The predominant behaviour is in the cathodic inhibitor mode. These compounds reduce the permeation current in 1 M HCl and enhance i t in 0.5 M H2SO4. The adsorption of these compounds on mild steel in 1 M HCl and 0.5 M H2SO4 obeys Langmuir's adsorption isotherm.