Effect of Corrosion on the Composition of Pulse‐Plated Cu‐Ni Alloys

Copper and nickel are codeposited by pulse and reverse‐pulse plating on a rotating cylinder cathode from a citrate bath. Polarization data for copper and nickel as well as potential transients during pulse and reverse‐pulse current experiments show that displacement reactions may occur during the pulse off‐time or pulse‐reversal time. A mathematical model which includes this effect is developed to predict the composition of electrodeposited alloys. The model shows that copper deposits at the mass‐transfer limiting current throughout the pulse‐cycle while nickel is alternately deposited and dissolved during the pulse on‐time and off‐time (or reversal time). The alloy composition is governed by pulse parameters and the diffusion limiting current for copper deposition.