The effect of hydroxyapatite nanoparticles on electrochemical and mechanical performance of TiC/N coating fabricated by plasma electrolytic saturation method

Abstract

In this study the hybrid Plasma Electrolytic Saturation-Electrophoretic Deposition (PES-EPD) method was used to deposit TiC/N + Hydroxyapatite (HA) composite coating on NiTi alloy. The Grazing Incidence X-ray Diffraction (GIXRD) and X-ray photoelectron spectroscopy (XPS) demonstrated that TiC0.2N0.8 and NiTiO3 were formed after the deposition process. Also, HA nanoparticles incorporated to the coating without any decomposition or reaction with the other phases. To evaluate the effect of HA nanoparticles on structural, mechanical and electrochemical performance of TiC/N coating, the field emission scanning electron microscope, the nano-indentation test and potentiodynamic polarization test were utilized. The results confirmed that, TiC/N + HA composite coating had low porosities and dense microstructure in comparison with TiC/N coating. Likewise, corrosion resistance of the composite coating in Ringer's solution was higher than TiC/N coating. Such behavior was related to the embedded HA nanoparticles in the coating which fill the coating porosities. The nano-indentation test results revealed that the incorporation of HA nanoparticles in TiC/N coating decreases its hardness and elastic modulus due to lower hardness and elastic modulus of hydroxyapatite than TiC/N.