Effect of electrophoretic deposition parameters on the corrosion behavior of hydroxyapatite-coated cobalt–chromium using response surface methodology

Cobalt–chromium (Co–Cr)-based alloys have been used extensively as medical implants, but the ion release and the corrosion products can affect their mechanical integrity and biocompatibility. One of the solutions is to surface coat the substrate with hydroxyapatite via electrophoretic deposition technique. Two variables—pH of electrolyte and current density—were used to examine the electrochemical behavior of the coated sample. An experimental strategy was developed based on the response surface methodology together with the analysis of variance to verify the precision of the mathematical models and their relative parameters. Close agreement was observed between the predicted models and the experimental results. The pH value of electrolyte was a more significant factor than current density in increasing the corrosion potential (Ecorr) of the substrate. The maximum Ecorr was obtained with a current density of 12 mA cm−2 and a pH value of 4.71