High-Speed Selective Electroplating with Single Circular Jets

High-speed selective electroplating of circular deposits with a jet system was investigated by both experimental and theoretical studies. Direct measurement of current distribution was made with a sectioned electrode made of concentricrings. Three systems were studied, including alkaline ferricyanide reduction, copper deposition from acidified sulfate solution, and copper deposition from an acidified sulfate solution that also contained a ferric/ferrous redox couple. In these systems, current distribution data were obtained upon controlled variation of jet Reynolds number, electrolyte conductivity, reactant concentration, and applied total current. A mathematical model of the process was developed that included mass transfer, ohmic resistance, charge transfer, cell geometry, and multiple electrode reactions. The mathematical model was used to generate dimensionless contour maps indicating generalized conditions under which selective high-speed electroplating can be accomplished.