Characterization of the 3YSZ/CNT/HAP coating on the Ti6Al4V alloy by electrophoretic deposition.

In this article, the effects of the simultaneous addition of the 3 mol % yttria-stabilized zirconia (3YSZ) and carbon nanotubes (CNTs) reinforcements on different properties of the natural hydroxyapatite (HAP) coating were studied. The electrophoretic deposition (EPD) process was implemented to prepare thin coatings on the Ti6Al4V substrate. The coatings were then sintered at 1000 ° C under vacuum for 2 hr and the mechanical properties of them were studied by the nano-indentation method. The microsture and phase content of the coatings were investigated by the scanning electron microscope and X-ray diffraction methods, respectively. The electrochemical properties of the samples were studied by potentiodynamic polarization and electrochemical impedance spectroscopy. The biocompatibility of the coatings was evaluated by the MTT test under standard conditions. It was found that the proper voltage and duration for the deposition of the coatings were 20 V and 4 min, while the longer deposition time of up to 6 min. Was tolerable in the coatings containing 5 wt % of the CNTs. The hardness and Young's modulus of the coatings were improved significantly by the siumultaneous addition of 3YSZ and CNTs, but the effect of nanotubes was more prominent. It was also found that the composite coating had marginally lower biocompatibility, as compared to the natural HAP, which was probably due to their lower roughness. The corrosion resistance of the HAP was not affected by the presence of 3YSZ particles, while the addition of CNTs improved the corrosion resistance of the coatings.