Inhibiting Effect and Mechanism of Organic Additive DA on Corrosion of Zinc in Alkaline Solution

摘要

Inhibiting effect of organic additive DA on corrosion of zinc in alkaline solution was studied through immersion test and electrochemical measurement and its inhibiting mechanism is discussed through calculation of thermodynamic and kinetic parameters. Results show that DA is an effective cathodic inhibitor and may become mercury-substituting inhibitor in alkalline zine-manganese batteries. Adsorption of DA on zinc surface is physisorption and obeys Langmuir isotherm. Both enthalpy and entropy changes are positive in the whole adsorption process, and so the adsorption is caused by entropy effect instead of enthalpy effect. Adsorption of DA on zinc surface lowers pre-exponential factor much more than Arrhenius activation energy of zinc corrosion reaction. Inhibition is mainly due to blocking effect instead of catalytic effect.