Corrosion resistance and bioactivity of SiO2-Y2O3 coatings deposited on 316L steel

Ceramic coatings consisting of SiO2-Y2O3 layers were deposited on 316L steel using the sol-gel technique. The Y2O3 layer was included to increase the build-up of apatite ceramic, and to improve the corrosion resistance of the steel to bodily fluids. Raman spectra and EDS analysis confirmed the increased presence of Ca and P on the surface of the samples after 220 days of exposure to simulated body fluid (SBF) when compared to three-layer SiO2 coatings. The nucleation of bone-like apatites on the coating surface is indicative of the bioactive effect of the Y2O3 layer. The high corrosion resistance of steel coated with Y2O3 and SiO2-Y2O3 layers was confirmed by the corrosion current densities and ICP-OES analysis of the SBF composition after exposure of the samples.