Effect of nickel ion concentration on Ni/Al2O3 composite coatings

The electrochemical preparation of Ni/Al2O3 composite coating is investigated by variation of electrolyte concentration. The agglomerated diameter of alumina particles can be reduced with the decrease of electrolyte concentration from 1109 nm to 178 nm at a bath concentration of 0.20 M4 nickel ions under the 5 W/L. with a 40 minute ultrasonic energy treatment. Furthermore. an effective dispersion of alumina particles in the electrolyte solution makes more opportunities for loose adsorption and strong adsorption of alumina particles on the electrode. The Ni/Al2O3 composite coating is prepared with variations of electrolyte concentration under reasonable electrochemical conditions. When the nickel ion concentration is 0.3-5 M. the volume content of alumina particles in this composite coating is increased to a maximum value of 26.78 vol.%. Meantime, the homogeneity of the composite coating is promoted by ail effective dispersion due to the decrease in the bath concentration.