Rotating Ring‐Disk Electrode Studies of Cu‐Ni Alloy Electrodissolution in Acidic Chloride Solutions: II . , , and Cu‐Ni Alloys

The electrodissolution kinetics of Cu‐5 Ni, Cu‐10 Ni, and Cu‐30 Ni alloys in acidic chloride solutions have been investigated with rotating ring‐disk electrodes at various anodic potentials, H + and Cl − concentrations, and rotation rates. The kinetics and mechanisms of electrodissolution of the Cu component for all three alloys are consistent with results obtained previously for Cu. Electrodissolution of the Cu component exhibitied mixed mass‐transfer and kinetic control in the apparent Tafel region and mass‐transfer control in the limiting current region with cuprous chloride complex indicated as the limiting diffusion species. At potentials above the limiting diffusion current region, formation rates of Cu(I) and Cu(II) were under mass‐transfer and kinetic control, respectively. The effective thickness of the surface film on the Cu‐Ni alloys decreased with increasing Ni content.