Zinc corrosion in NH4Cl and effect of some organic inhibitors

Abstract The corrosion of zinc in ammonium chloride, both pure and containing various organic compounds, has been studied by means of analytical and electrochemical methods as the determination of the zinc dissolved and the hydrogen evolved, I ( V ) curge recording and impedance measurements. The results obtained in a potential region near the zinc corrosion potential showed that the cathodic reaction of hydrogen discharge does not fit a simple exponential law because the Tafel coefficient appears to be electrode potential dependent. The experimental findings proved that only five of the 25 organic substances tested have been found to behave as zinc corrosion inhibitors (NDA, POELE, FORAFAC, TTH and TRITON in decreasing order of influence).