In Vitro Evaluation of Degradation of a Calcium Phosphate Coating on a Mg-Zn-Ca Alloy in a Physiological Environment

Magnesium alloys would get considerable attention as biodegradable temporary implants if their corrosion resistance could be enhanced to the required level. In this study, the calcium phosphate (Ca-P) coating was deposited on a biodegradable magnesium alloy using the electrochemical deposition method with a view to controlling the degradation rate as well as enhancing the bioactivity. The coating morphology and chemistry were characterized using scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDXS), and x-ray diffraction (XRD). The resistance to electrochemical degradation, as a result of the Ca-P coating on the magnesium alloy, in modified simulated body fluid (m-SBF) was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of this study show that the Ca-P coating significantly decreases the degradation rate of the magnesium alloy, indicating the potential of the Ca-P coating to be used as a corrosion barrier for temporary implant materials.