Electrochemical study of the cathodic protection efficiencies of selected anions on galvanised steel in acidic medium

The cathodic protection efficiency of selected anions were investigated on galvanized steel surface in acidic medium. The results reveal that the inclusion of the electroactive anions (OH ⁻, I ⁻, Br ⁻, Cl ⁻, NO ⁻₃, MnO₄⁻ and F ⁻) in the acidic corrodent enhanced the cathodic protection with high efficiency for the less electronegative ions and vice versa. The average cathodic protection efficiency recorded for the anios follow the trend OH ⁻ (78.3%) > I ⁻ (74.4%) > Br ⁻ (69.2%) > Cl ⁻ (63.8%) > NO ⁻₃ (60.7%) > MnO₄⁻ (59.6%) F ⁻ (57.9%). Chemical adsorption mechanism has been proposed for the electroactive anions.