Optimization of process parameters on the response of corrosion resistance of electroless Ni-Co-P coating using Box-Behnken Design (BBD)

Abstract

Ternary Ni-Co-P alloy coating was chosen to improve the corrosion resistance of the Copper substrate. Box-Behnken Design (BBD) of experiment was utilized for the optimization of the effects of different process parameters such as Cobalt Sulphate, Sodium Hypophosphite, and temperature. Electrochemical Impedance Spectroscopy (EIS) was used to study the corrosion resistance behaviour of different samples by altering different parameters. Analysis of Variance (ANOVA) was done to determine the important process parameters and their significant interactions. The surface morphology, microstructures and elemental compositions of the as-deposited coatings were analyzed using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Energy Dispersive X-Ray Spectroscopy (EDX) respectively. Finally, 15g/L of Cobalt Sulphate, 25g/L of Sodium Hypophosphite, and 85°C of bath temperature were found out to be the optimum conditions for coating deposition in order obtain a corrosion resistance of 1165 ohm-cm2.