Ethanolamines as corrosion inhibitors for zinc in (HNO3 + HCl) binary acid mixture
By R. T. Vashi and H. M. Bhajiwala
The inhibition effect of ethanolamines on zinc in (HNO3 + HCl) binary acid mixture has been studied by weight loss method and polarization techniques. Corrosion rate increases with the concentration of acid mixture. The inhibition efficiency (I.E.) of ethanolamines increases with the concentration of inhibitors. Corrosion rate increases while I.E. decreases with increase in temperature. 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. Potentiostatic polarization results revealed that ethanolamines act as mixed typed inhibitors.
Key words: Corrosion, zinc, nitric acid and hydrochloric acid mixture, ethanolamines.