Morphology of Nanostructured TiO2 Surfaces for Biomedical Implants Developed by Electrochemical Anodization

Ti6Al4V alloy is widely used for biomedical implants, and the modification of its surface, at nanoscale level, is a method to enhance its osseointegration. We modified the Ti6Al4V surface, with an initial micro rough topography, by using electrochemical anodization in 1M H3PO4 + 0.5 wt% HF electrolyte, and anodization potential of 20 V. By using short anodization duration, 5 min, or 15 min, the oxide layer presents a nanoporous morphology, and do not cover the entire surface. At an anodization time of 30 min, our results demonstrate the synthesis of continuous, highly ordered nanotubular TiO2 layer (diameter of nanotubes: 25-90 nm, thickness of the layer: 350-450 nm), superimposed over a micro rough topography, the oxide layer exhibiting a good adherence to the substrate, coherence and no brittleness. Anodization time of 2 hours provides the results very similar with those obtained at 30 min in terms of nanotubular layer topography, but some drawbacks appear in terms of surface coverage and continuity of the layer.