Commercially pure Ti and Ti6Al4V are the most widely used metallic biomaterials for orthopaedic applications due to their overall good osteointegration capacity, inertness and non-toxicity. Nevertheless, the introduction of an implant in the body is always associated with the risk of microbial infection in particular for the fixation of open-fractured bones and joint-revision surgeries. Considering that the bacteria adhesion mechanisms are very similar to those of the host’s osteogenic cells, once an implant is inserted, the occurrence of infection is dependent on the relative speed by which osteogenic cells and bacterial cells adhere to the implant surface. Moreover, cell and tissue responses are affected not only by the chemical properties of the implant surface, but also by the surface topography and roughness. To this aim specific surface treatments which favor osteointegration and simultaneously discourage bacterial adhesion are required. The anodization of Ti with the formation of TiO2 nanotubes is a cheap method which can lead to an increase of the surface roughness at a nanoscale and enhance osteointegration. Moreover, combined with post anodization annealing or drug loading, the nanotubes porosity could also hinder the bacterial adhesion. The present work focuses on the effect of the anodizing parameters such as applied voltage and time to the microstructure and corrosion resistance of the obtained films. Commercially pure Ti and Ti6Al4V plates have been anodized using an ethylene glycol electrolyte containing 0.5wt.% NH4F and 2.5% V H2O. The applied voltage varied from 20 to 120V and the anodization time from 30 to 180 min. The obtained films have been characterized by SEM and XRD regarding the microstructure with particular attention to the structure of TiO2 nanotubes on the α and β phase grains of Ti6Al4V.
