The Effect of Titanium Dioxide (TiO₂) Nanoparticles on Hydroxyapatite (HA)/TiO₂ Composite Coating Fabricated by Electrophoretic Deposition (EPD)

Composite coatings of Hydroxyapatite (HA) with ceramics, polymers and metals are used to modify the surface structure of implants. In this research, HA/TiO₂ composite coating was fabricated by electrophoretic deposition (EPD) on 316 stainless steel substrate. HA/TiO₂ composite coatings with 5, 10 and 20 wt.% of TiO₂, deposited at 40 V and 90 s as an optimum condition. The samples coated at this condition led to an adherent, continuous and crack-free coating. The influence of TiO₂ content was studied by performing different characterization methods such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), corrosion resistance in simulated body fluid (SBF), coating’s dissolution rate in physiological solution and bond strength to the substrate. The results showed that the higher amount of TiO₂ in the composite coating led to increase in bond strength of coating to stainless steel substrate from 3 MPa for HA coating to 5.5 MPa for HA-20 wt.% TiO₂ composite coating. In addition, it caused to reduction of corrosion current density of samples in the SBF solution from 18.92 μA/cm² for HA coating to 6.35 μA/cm² for HA-20 wt.% TiO₂ composite coating.