SILVER-GOLD ALLOYS PREPARED BY PULSE PLATING - MODELING OF THE CHEMICAL-COMPOSITION

The individual and simultaneous deposition of silver and gold from low cyanide concentration solutions showed two regions in the potentiodyn amical j-E curves. At low overpotentials, these processes take place t hrough adsorbed species while at high overpotentials the normal diffus ional region is observed. Then, when pure silver and gold deposits are prepared by galvanostatic pulse plating, the presence of adsorbed spe cies cannot be disregarded. This phenomenon prevails and has an import ant effect when silver and gold are simultaneously deposited by pulse plating. Therefore, the chemical composition of the alloys is describe d by a model in the activation region while another model was deduced for the diffusional region. The models take into account typical param eters of pulse plating and were developed by application of the statis tical experimental design methodology.