ELECTROLYTIC CODEPOSITION OF NI-GAMMA-AL2O3 THIN-FILMS

The effects of current density, particle concentration, and agitation on Ni-gammaAl2O3 composite electrodeposition have been investigated an d a comparison made to the deposition of pure nickel using a rotating disk electrode. The nickel deposition efficiency and nickel polarizati on behavior are both substantially altered by the presence of alumina particles in the bath. Troughs in the nickel efficiency and kinks in t he nickel polarization curves were observed which were not present dur ing the deposition of pure nickel. The appearance of anomalous behavio r in these measurements coincides with the appearance of a peak in par ticle incorporation into the film. This behavior has been ascribed to competition between the charge-transfer controlled nickel deposition r eaction, and the mass-transfer limitation of the alumina deposition pr ocess at high currents.