Electrodeposition of Nickel by an Asymmetric Periodically Reversed Step Current

We report he investigation ofhigh current density (-0.15 A/cm 2) nickel electrodeposition with a periodically reversed step current and the characterization f the surface morphology of the coatings thus produced. The deposits how micro-structure coherency, characteristics of columnar growth, diameter and shape of growth features, and porosity, which are current controlled. For the same total deposited mass, the deposit thickness i shown to be a function of periodically re-versed step current parameters. The control of deposit layers allows the fabrication of nickel coatings with well-defined mechanical and electrocatalytic properties. Metal plat ing under steady current density may re-sult in an i rregular morphology of the deposit idue to the depletion of ions at the cathode. Methods involv-ing agitation or air sparging may reduce this problem by decreasing the thickness of the diffusion layer, but pulse techniques have been shown to provide the best method of obtaining good fil l ing and coherency of the deposit (1)