The synergistic effect of Halide ions on the corrosion inhibition of zinc by n-decylamine

Abstract

The effect of halide ions on the spontaneous dissolution and the anodic and cathodic polarization of zinc in perchloric acid solution with and without n-decylamine has been studied. Halide ions enhanced the corrosion of zinc, whereas n-decylamine inhibited the corrosion of zinc. The inhibitor efficiency of n-decylamine is increased significantly by the presence of halide ions. A consistent surface coverage value is obtained both from weight loss and polarization studies. n-decylamine acts mainly as a cathodic inhibitor. The change in the free energy of adsorption of n-decylamine in the presence of halide ions is explained in terms of a change in the mechanism of corrosion inhibition. Synergism of n-decylamine and halide ions is discussed from a view point of a model of co-adsorption of halide ions and n-decylamine.