Effects of calcium salts on microstructure and corrosion behavior of micro-arc oxidation coatings on Mg-2Zn-1Ca-0.8 Mn alloy

Micro-arc oxidation (MAO) in an alkaline disodium hydrogen phosphate electrolyte containing different calcium salts has been used to produce oxide coatings on self-designed Mg-2Zn-1Ca-0.8 Mn alloy as a potential biodegradable bone implant material. SEM with EDS, XRD and FT-IR were used to characterize microstructures, elemental distribution and compositions of the MAO coatings. Potentiodynamic polarization curves and corrosion morphologies of the coating in the SBF solution are also presented. The results show that the coatings formed in (CH3COO)(2)Ca-containing electrolyte exhibit better apatiteinducing ability. However, the coatings formed in Ca(C6H11O7)(2)center dot H2O-containging electrolyte show lower corrosion resistance than those formed in (CH3COO)(2)Ca and (C6H5O7)(2)Ca-3 center dot 4H(2)O containing electrolyte. (C) 2017 Elsevier B. V. All rights reserved.