Titanium Anodic Oxidation: A Powerful Technique for Tailoring Surfaces Properties for Biomedical Applications

Titanium biomaterials are widely employed to produce medical components, such as prostheses, plates and screws or dental implants. Their diffusion is ascribed to the broad spectrum of optimal mechanical and surface properties, such as the corrosion resistance and correlated low ionic release, the bio-compatibility, and especially, the enhanced osseointegration that can be achieved by surface modifications, particularly by suitable anodizing treatments. The anodic oxidation technique consists of polarizing titanium by imposing a current flow between the titanium specimen and a counterelectrode. The process parameters which most determine the properties of the growing oxide are the electrochemical ones as well as the electrolyte specifications and, of course, the composition of the metal itself and its surface conditions. Tuning the operating process parameters it is possible to obtain TiO₂ films that differ in terms of thickness, ranging from thin colored films up to complex micrometric thick ones; morphologies, from smooth to nanotubolar surfaces; oxide structures — from amorphous to anatase and rutile; and compositions. A precise and robust control of the anodizing process is of fundamental importance in tailoring properties of TiO₂ surfaces for biomedical applications.