The initial stage in the anodic dissolution of copper-gold alloys in chloride and sulfate solutions

Prior to emergence of diffusion limitations in a solution or an alloy, but after attaining equilibrium by the first single-electron stage of charge transfer, the initial stage in dissolution of copper and copper-gold alloys (4 to 50 at. % of Au) is limited by surface diffusion of copper adatoms between linear atomic steps both in sulfate and chloride solutions. Copper atoms emerge from semicrystalline or kink-positions at a greater but comparable rate. Mobility of adatoms decreases with the growing gold concentration, which is attributed to specificity of interactions between atoms in the alloy crystal lattice. The Cl- anions directly participate in a copper ionization act, which noticeably accelerates surface diffusion of adatoms in chloride solutions compared with sulfate solutions.