Corrosion behaviour of zinc in alcohol‐water solvents

Abstract

PurposeThe aim of this paper is to elucidate the mechanism and the effect of different monohydric organic solvent on the corrosion behaviour of zinc in distilled water.Design/methodology/approachThe corrosion behaviour of zinc in stagnant distilled water containing 0‐70 percent (v/v) methanol, ethanol or n‐propanol was investigated at 25‐40°C using potentiodynamic polarization technique. The activation parameters that govern zinc corrosion in mixed solvent system were also calculated.FindingsThe data revealed that, the corrosion of zinc in mixed solvents depends on two factors: the hydrolysis rates of the metal ions in alcohol‐water solutions and the chemisorption of organic solvent molecules at the metal surface. When the latter effect predominant the final result is an increase of the inhibiting effect. On the other hand, when the first factor is dominant the final result is a decrease in the protection efficiency and may exhibit an accelerating effect.Research limitations/implicationsSpecial attention should be made on using mixed water‐alcohol solvents. Methanol, 50 percent (v/v), has unexpected accelerating effect whereas 70 percent (v/v) exhibits protection efficiency of ≈58 percent.Originality/valueOwing to environmental concerns, the use of alcohol in automotive fuel increases. Therefore, it is of importance to study the corrosion behaviour of zinc in alcoholic solution.