INHIBITING AND ACCELERATING EFFECTS OF SOME QUINOLINES ON THE CORROSION OF ZINC AND SOME BINARY ZINC-ALLOYS IN HCL SOLUTION

The effect of quinoline, benzo(f)quinoline and 8-hydroxyquinoline on the electrochemical and corrosion behaviour of zinc, Zn-2% Cd and Zn-2 % Pb alloys in deaerated 0.1 M HCl solution was studied using the potentiostatic technique. Although quinoline inhibited the corrosion of zinc at all examined concentrations, it accelerated the corrosion of the alloys. As an inhibitor, quinoline was found to have a predominant anodic effect and its adsorption conformed with the Temkin isotherm. At concentrations > 10(-4) M, benzo(f)quinoline inhibited the corrosion of both zinc and the alloys. Inhibition was found to be predominantly anodic without changing the mechanism of zinc dissolution. Inhibition by 8-hydroxy quinoline was found to be purely anodic occurring by surface chelation, resulting in a change of the mechanism of zinc dissolution.