Construction and characterization of micro/nano-topography on titanium alloy formed by micro-milling and anodic oxidation

The surface micro/nano-topographical modifications have been widely used in improving the biocompatibility of biomedical implants. In this paper, the feasibility of the micro-milling process for construction of micro-grooves without burrs on titanium alloy materials was investigated. Low melting point alloy was selected as supporting material to extend the boundary of the workpiece, so the burrs produced on the surface of supporting material. A novel hierarchical micro/nano-topography with micro-grooves and TiO2 nanotubes was fabricated on titanium alloy surface combining micro-milling and anodic oxidation. The scanning electron microscope, energy-dispersive spectroscopy, laser scanning microscope, and contact angle tester were used in characterizing surface features of machined workpieces. Results showed that the micro-grooves with dimension of 40 mu m in depth were machined using V-shaped cutting tool, and the TiO2 nanotubes with dimension of 70 nm in diameter were superimposed on the surfaces of micro-grooves by anodic oxidation. In addition, the hydrophilicity of micro/nano-structured surface was significantly enhanced with the water contact angle decreasing from 114.8A degrees to 60.3A degrees. It is concluded that this hybrid method combining micro-milling technology and anodic oxidation can be used in improving the biological activity of biomedical implants through changing surface topographies.