Corrosion inhibition effect of ethylamines on zinc in (HNO3+H3PO4) binary acid mixture
By R. T. Vashi, H. M. Bhajiwala
The inhibition effect of ethylamines on zinc in (HNO3+H3PO4) binary acid mixture has been studied by weight loss and polarization techniques. Corrosion rate increases with concentration of mix acid. The inhibition efficiency of ethylamines increases with the inhibitor concentration. The adsorption of inhibitor on zinc surface has been found to obey Langmuir adsorption isotherm. The values of activation energy (Ea), free energy of activation (∆Ga), Heat of adsorption (∆Qa), enthalpy of adsorption (∆H) and entropy of adsorption (∆S) were calculated. Corrosion rate increases and inhibition decreases with rise in temperature. Potentiostatic polarization results revealed that ethylamines act as mixed typed inhibitors.
Keywords : Corrosion, Zinc, Nitric and Phosphoric acid mixture, Ethylamines.