Fabrication of SiO2 nanoparticles incorporated coating onto titanium substrates by the micro arc oxidation to improve the wear resistance

In order to improve the tribological performance of titanium substrates, Micro arc oxidation (MAO) technique was employed to fabricate SiO2 nanoparticles incorporated coating onto titanium substrates. Surface microstructure and chemical composition of the oxide layers were examined by means of scanning electron microscope with Energy Dispersive X-ray Spectroscopy (SEM/EDS), X-ray Photoelectron Spectroscopy (XPS) and X-ray diffraction (XRD). Structure analysis revealed that spherical SiO2 nanoparticles were uniformly deposited on the substrate surface and most of the particles were embedded into the MAO coating. Silicon element as discovered from the EDS and XPS analysis confirmed the successful incorporation of SiO2 nanoparticles. Microhardness and tribological behavior of the MAO coating were evaluated by using Vickers hardness apparatus and ball-on-disc test in simulated body fluid (SBF). The results show that after SiO2 nanoparticles incorporation, the mechanical strength and wear resistance of MAO coatings were increased. Meanwhile, the in vitro study indicates that the SiO2 incorporated samples retained similar cytocompatibility to that of native titanium substrates and would be a potential candidate for the development of biomedical devices.