Role of the thiocyanate ion in the corrosion inhibition of zinc in perchloric acid by n-decylamine

The effect of KSCN on the corrosion of electropolished zinc in 0.1 M HClO4 and 0.1 M HClO4 solution containing different concentrations of n-decylamine (nDA) has been investigated using weight loss and polarization methods. The inhibitor efficiency of nDA increased markedly in the presence of KSCN. pH and temperature affected the corrosion inhibition of zinc by nDA in acidic KSCN solution. The weight loss and polarization measurements gave consistent results. nDA in acidic KSCN solution acted mainly as a cathodic inhibitor, but with a smaller degree of anodic control. The increase in the inhibitor efficiency of nDA in the presence of KSCN is discussed from the viewpoint of the co-adsorption of nDA in cationic form and thiocyanate ions. © 1979