Functionally graded HA–TiO2 nanostructured composite coating on Ti–6Al–4V substrate via electrophoretic deposition

Abstract

Abstract In the present study, electrophoretic deposition was carried out in the ethanol-based suspensions at the voltage of 20 V for 3 min to form functionally graded coatings of HA/TiO 2 nanoparticles and HA–TiO 2 nanocomposite coatings with 0, 10 and 20 wt.% of TiO 2 on Ti–6Al–4V substrate. The gradual addition of HA suspension into the deposition cell containing TiO 2 nanoparticles caused the functionally graded structure of HA–TiO 2 coatings. The microstructure of coatings showed the lower porosities by the addition of TiO 2 and using graded structure. The pull-off test results showed the highest bonding strength for the graded coating. The electrochemical impedance spectroscopic studies after in vitro tests, revealed that the total corrosion resistance of graded coating is higher than that of HA and HA–TiO 2 samples. The accelerated apatite formation on functionally graded coating corresponding to inductively coupled plasma spectroscopy was attributed to the higher wettability of its surface.