Inhibition of Corrosion of Zinc in Sulphamic Acid

Abstract

The inhibition by sulphanilamide and phenyl diamine tetraacetic acidof the corrosion of zinc in sulphamic acid solution has been studied inrelation to the  concentrations of inhibitors and temperature. In plainsulphamic acid, the corrosion increases with the temperature. Inhibitionefficiency increases as the concentration of inhibitor increases. At 15 mMinhibitor cocentration in 0.1 M sulphamic acid, the efficiency of sulphanilamidewas found to be 78%, whereas 75% for phenyl diaminetetraacetic acid. The mode of inhibition action appears to be the chemisorptionbecause the plot of log   θ/1-θ versus log C giving a straight line suggeststhat the inbibitors cover both the anodic as well as cathodic regions throughgeneral absorption Langmuir isotherm. Galvanostatic polarization curvesshow both anodic and cathodic polarization in both inhibitors studied.