The Anodic Corrosion of Gold in Concentrated Chloride Solutions

Abstract

The anodic corrosion of gold has been studied in concentrated chloride solutions as a function of chloride concentration and pH. Results are discussed in terms of five potential regions: active, prepassive, active‐to‐passive transition, passive, and transpassive. The existence of HAuCl2 with a dissociation constant of the order of 1 to 10 and a mechanism for the active dissolution of gold are postulated. The relation between the breakdown of the passivating film in the transpassive region and the gold dissolution and chlorine evolution reactions is discussed.