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

Substituted tertiary arsine and phosphines as interfacial adsorption inhibitors for corrosion of zinc in perchloric acid

The effect of triphenylarsine, triphenylphosphine and tri-p-tolylphosphine on the corrosion of zinc in HClO4 at 30° C was studied. A significant decrease in the corrosion rate of zinc is obtained by the addition of these compounds. The corrosion rate is a function of the temperature, pH of the medium and the concentration of the inhibitors. The percentage protection calculated from weight loss and polarization methods are in good agreement. The apparent free energies of adsorption of inhibitors for different possible modes of adsorption are evaluated. The experimental data obtained are in agreement with the corrosion inhibition of zinc by interfacial adsorption of inhibitors. © 1980 Chapman and Hall Ltd

EFFECT OF BENZOQUINOLINES AND ACRIDINE ON THE CORROSION OF ZINC IN HYDROHALIC ACIDS.

The effect of benzo(f)quinoline, benzo(h)quinoline and acridine on the corrosion of zinc in hydrohalic acids has been studied. Halide ions accelerate the corrosion whereas quinolines and acridine act as corrosion inhibitors. Halide ions enhance the protection of zinc by each inhibitor. The polarization data reveal that these inhibitors act as ambiodic inhibitors. The mechanism of corrosion inhibition is discussed on the basis of coadsorption and synergistic effect of anions and inhibitor molecules

The effect of thiocyanate ions on the corrosion of copper in perchloric acid

The effect of thiocyanate ions on the corrosion of copper in 0.1 M HClO4 was investigated in the presence of various concentrations of thiocyanate ions using weight loss and polarization methods. The corrosion rate decreased markedly in the presence of thiocyanate ions and maximum percentage protection (93.7%) was obtained at 10-3 M thiocyanate ions. The drift of the corrosion potential in the less noble direction and the increase in the anodic Tafel slope are consistent with the inhibition by thiocyanate ions of both the anodic and the cathodic reactions of the corrosion process. The variation in the corrosion rate with the concentration of thiocyanate ions is attributed to the specific adsorption of thiocyanate ions and precipitation of cuprous thiocyanate on the copper surface. © 1980