Fabrication And Properties Study On Bioactive Coating On The Ti6Al4V

Titanium alloys have excellent properties of high strength, biocompatibility and corrosion resistance and become one of the best substituting materials of hard organizations, such as bone and tooth. However, because of the poor surface bioactivity,leading to the weak binding capacity with bone, it is important to modify the surface to improve the bioactive property, as well as the anticorrosion and biological properties.In this paper, the bioactive coatings were fabricated on the surface of Ti6A14V substrate using Micro-arc Oxidation method by changing electrolytic systems and technical parameters.The surface morphology, bioactive elements contents and the phase composition were explored by scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and X-ray diffraction (XRD). The effect of electrolytic component and concentration, pulse voltage, frequeney, duty-cycle and treating time on the morphology, bioactive elements contents, thickness of the coating and phase composition of the bioactive coating has been studied in order to optimalize the electrolytic systems and technical parameters. According to the results above, the corrosion resistance, the bonding strength, the wetting and the bioactivity of the coatings were studied by CHI660B electrochemical analyser, the tensile testing machine, JC2000A static contact angle meter and immersion in vitro.The results showed that the surface morphology, bioactive elements contents and the phase composition of the porous coating were mainly affected by electrolytic component and concentration, pulse voltage and treating time. The bioactive coating with homogeneous pore size and good compactness can be obtained on the surface of Ti6A14V substrate in the electrolyte comprising Ca(CH3COO)2 and Na2HPO4 with c(CaAc) of 0.15mol/L, c(Na2HPO4) of 0.10mol/L, pulse voltage of 450V, frequeney of 800Hz, duty-cycle of 30%, and treating time of 20 min. The bioactive coating is mainly composed of anatase TiO2 and rutile TiO2, the binding strength between coating and substrate reaches 53.7 MPa. The corrosion potential of the coating was -0.060V, which had been obviously increased by 0.134V compared with Ti6A14V substrate. The hydroxyapatite could be formed on the surface of the coating after soaked in the SBF for 7 days, which suggested that the MAO coatings possess good bone inducement ability.