Investigations on effect of process parameters of electrodeposited Ni-Al2O3 composite coating using orthogonal array approach and mathematical modeling

This research article aims at preparation of nickel-aluminum oxide (Ni-Al2O3) metal matrix composite coatings that were prepared from conventional electro-deposition process. Micron sized alumina particles were deposited in nickel matrix by electro-co-deposition technique. The primary electroplating parameters of current density, pH value of electrolyte, temperature of bath, amount of ceramic particles (Al2O3) in bath, and agitation speed were considered for experimental studies. Experimental design and run orders were framed by orthogonal array of Taguchi's approach. L27 orthogonal array was chosen for experimental design based on five plating parameters and three levels. The experiments were conducted by adjusting the plating parameters and the samples were prepared from electrolytic bath. Volume fraction of Al2O3 and micro-hardness of deposits were recorded for each coated sample systematically. The mean effect studies of electroplating parameters were investigated using Taguchi's approach. The S/N ratio values for the response of micro-hardness were calculated and analyzed for significances of independent input parameters. It was found that current density, pH, temperature and agitation speed were the most significant factors. A second order quadratic equation was developed as prediction model for micro-hardness. The predicted micro-hardness values were found to be in good agreement with the experimental results.