The Anodic Behavior of Gold in Sulfuric Acid Solutions: Effect of Chloride and Electrode Potential

The anodic behavior of gold has been studied in containing 0, 1, and at potentials in the passive and in the transpassive regions. The reaction products are soluble Au (III) and an film. Their rates of formation and the potential dependence of the rates are functions of the chloride concentration. Chloride promotes the dissolution of gold and reduces the rate of film formation. The composition of the film and the mechanism of its formation are not affected by the presence of chloride in solution. Two mechanisms of oxygen evolution exist. At low potentials, oxygen is evolved on the metal surface; at high potentials, the process occurs on the film. At high potentials, the film formation and the oxygen evolution reactions have the same rate‐determining steps. The implications of this study to the corrosion of gold conductors on electronic circuits are discussed.