Characterization of silicon- substituted nano hydroxyapatite coating on magnesium alloy for biomaterial application

In this study, effects of substitution of Si in structure of HA (Si-HA) as coating on Mg alloy were investigated. The reverse pulse electrodeposition process with frequency of 10 and duty cycle of 0.1 was selected for coating. Four different electrolytes with different molars of SiO32− (0, 0.0025, 0.005 and 0.0075) were prepared in order to deposit Si-HA coatings on Mg alloy. The XRD and FTIR results showed that the main phase of deposited coatings was HA, and elemental analysis of coating confirmed the presence of Si in coatings. FE-SEM images of coatings indicated the presence of SiO32− in electrolyte caused a decrease in coating thickness and an increase in its compactness. The coating prepared by the electrolyte containing 0.005 mol/L SiO32− had higher corrosion resistance than that of HA coating as indicated by electrochemical tests. The cell experiment tests also showed that this high corrosion resistance coating had the nearest cell proliferation toward negative control.