Zinc as a Cathodic Inhibitor

It was shown that zinc metal in close contact with a noble metal such as silver furnishes zinc ions to an aqueous solution. A binuclear zinc hydroxide complex cation seems to be formed which can act as a cathodic inhibitor. This ion also acts as a buffer removing CO2 and it reacts with the oxygen in the water to give additional hydroxide ions. Considerable attention is given to the investigation of the nature of zinc complexes. Other topics discussed include nature of the cathodic protective coating forming on zinc, effect of the addition on impurities to zinc, and peptizing effect of the zinc hydroxide complex. 5.8.4