Electrochemical characterization of electrophoretically deposited hydroxyapatite/chitosan/graphene oxide composite coating on Mg substrate

Abstract Magnesium alloys are promising for hard tissue implants due to stupendous advantages including biodegradability and similar mechanical properties to natural bone. However, high degradation rate in body environment is main disadvantage for widespread applications of Mg alloys. In the present study, the alloy of Mg-4 % Zn- 4 % Sn-0.6 % Ca-0.5 % Mn was at first prepared by casting and subsequent extrusion, then was coated by hydroxyapatite/chitosan (HA/CS) with different graphene oxide (GO) content through electrophoretic deposition method (EPD). The effect of GO value and electrodeposition potential were studied on the morphology, chemical features and corrosion behavior of coating. Accordingly, coated samples were characterized by Fourier Transformation Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS). The results revealed the improvement of corrosion resistance for all coated samples and the optimum values of additional GO and applied potential were found to be 1 % and 150 V, respectively. The microstructure of the coatings showed a significant relationship between the soundness of coating and corrosion resistance which might be due to the formation of well dispersed, low porosity and relatively dense composite coating.