Study Of TiO₂ Nanotubes And Nano Hydroxyapatite（nHA） Preparation And Properties On The Surface Of Pure Titanium

Titanium and its alloys have a broad application prospect as the implanting materials due to their low elastic modulus, high specific strength, good corrosion resistance and biocompatibility. For a bone implanting materials, it must have a good bioactivity to promote the rapid combination with bone tissues. However, titanium and its alloys themselves are biologically inert materials. Therefore, in this thesis, the pure was taken as a reaserch subject, and the Ti O2 nanotube arrays were prepared on its surface by using anodic oxidation method. The effects pf the processing parameters on the morphologies of the TiO2 nanotube arrays were investigated. The hydrophilicity and the biocompatibility of the treated surface were evaluated. Furthermore, Ti/TiO2 array/ hydroxyapatite coating was prepared by electrochemical deposition method, and the interface bonding strength and biocompatibility of the coating were investigated. The main conclusions are as follows:(1) Using NH4F/glycerol as the electrolyte, the order TiO2 nanotube arrays were successfully prepared in situ by anodic oxidation method on titanium surface and the effects of the processing parameters on the morphology of TiO2 nanotube arrays were optimised. The results show that TiO2 nanotube arrays obtained under 20 V at 30℃ for 12 h are orderly arranged with a diameter in the range of 40-140 nm and a length more than 4μm. The TiO2 nanotubes are in an anatase structure after they were annealed at the temperature of 550℃.(2) The hydrophilicity and the biocompatibility of TiO2 nanotube arrays were evaluated. The results show that the TiO2 nanotube arrays exhibit an excellent hydrophilicity. The vitro cytotoxicity test results indicate that the TiO2 nanotube arrays have a good biocompatibility with no obvious toxicity. Meanwhile, the Ti O2 nanotube arrays with a high hydrophilicity show a superior biocompatibility.(3) The Ti/TiO2/nHA composite coating was successfully obtained on the Ti surface with the TiO2 nanotube arrays by electrochemical deposition method. The effects of the parameters on the morphology of HA coating were investigated. The results show that the HA coating surface obtained with 3mA/cm2 current density at 50℃for 30 min is smooth. The grains of the HA coating are uniform with a size in the range of 60-120 nm. The grain is arranged vertically, which has a certain gap between each other.(4) The bonding strength and biocompatibility of the coating were evaluated. The results show that the bonding strength is 26.7±2MPa, indicating the significant improvement of the bonding strength between the coating and the substrate. In vitro cytotoxicity test results indicate that the coating exhibit excellent biocompatibility with no obvious toxicity.