Optimization of Corrosion Rate of Coatings Using RSM and Particle Swarm Optimization Algorithm

Abstract

This study focuses on the electroless deposition of Ni–P alloy over a copper substrate to minimize the corrosion rate of the substrate. Central Composite Design (CCD) has been performed using Design-Expert software for minimizing the corrosion rate of the coating. Along with that, CCD is also utilized to analyze the influence of various process parameters viz. concentration of Nickel Sulphate, the concentration of Sodium Hypophosphite and bath temperature. Potentiodynamic test has been employed to evaluate the corrosion rate of each of the coated substrates. In order to minimize the corrosion rate, optimization has been performed using particle swarm optimization (PSO). 21.59[Formula: see text]g/L of Nickel Sulphate, 26. 72[Formula: see text]g/L of Sodium Hypophosphite and 93.41°C as the bath temperature were the optimum conditions for the deposition of coating in order to achieve a corrosion rate value of 0.862[Formula: see text]mm/Yas obtained from the model analysis results. Further, Analysis of Variance (ANOVA) was implemented which corroborated that the parameter Nickel Sulphate along with the interaction between Sodium Hypophosphite and bath temperature were the significant ones in determining the corrosion rate of the coating deposited in optimized condition. Optical Microscopy, Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray analysis (EDX) were conducted to study the surface morphology and the elemental composition of the coated substrate respectively.