ELECTROCHEMICAL STUDY OF SIC PARTICLE OCCLUSION DURING NICKEL ELECTRODEPOSITION

Previous, published work conducted by the Bureau of Mines showed that chromium particle occlusion occurs as a result of particle collisions with the cathode surface. Conductive chromium particles within the electric field were also shown to cause a local rise in the cathodic current density on the area immediately adjacent to that particle. In order to research the effect of conductive particles vs. semiconductive particles on the occlusion process, nickel electrodeposition was studied in the presence of SiC particles and compared to previous studies on nickel electrodeposition in the presence and absence of Cr particles. The effect of semiconductive SiC particles on nickel electrodeposition was to catalyze the formation of H(ads) as well as Ni+(ads) intermediates. Evidence of a H(ads) intermediate was obtained by current efficiency studies of Ni electrodeposition as well as x-ray diffraction and hydrogen analyses of the coatings made during electrodeposition.