Characterization of functionally graded hydroxyapatite/TiO2 multilayer coating on Ti-6Al-4V titanium alloy by electrophoretic deposition

Single layer and functionally graded coatings of hydroxyapatite and TiO2 particles were deposited on Ti-6Al-4V titanium alloy substrate by electrophoretic deposition technique (EPD). The coatings chemical composition and morphology were investigated using energy dispersive X-ray spectroscopy (EDX), scanning electron microscope (SEM) and X-ray diffraction (XRD) methods. The results showed in HA/TiO2 functionally graded coating, the composition varied from inner layer to top layer as 100 %wt TiO2 to 100 %wt HA. To investigation biocompatibility of the coatings, the culture Wharton’s Mesenchymal Stem Cells was used. The results showed the HA/TiO2 functionally graded coating and HA single layer coating were more biocompatible in comparison to TiO2 single layer coating. The adhesion strengths of the coatings were measured by shear testing and the results showed that the HA/TiO2 functionally graded coating has more adhesion strength (~31 MPa) compare to HA single layer.