Surface studies of coarse-grained and nanostructured titanium implants.

The results of XPS measurements of nanostructured Ti (ns-Ti) prepared with a help of severe plastic deformation (SPD) have been presented. We have measured XPS spectra of core levels (Ti 2p, O 1s, C 1s, F 1s) and valence bands before and after treatment of ns-Ti-implants in HF. The obtained data have been compared with XPS measurements of untreated and acid treated coarse-grained Ti (cg-Ti). According to these measurements the surface composition has not practically been changed by reduction of grains size of Ti-implants. It has been found that the surface of both types of implants is covered with thick TiO2 layer. The acid treatment reduces the surface contamination of ns-Ti and cg-Ti by hydrocarbons and induces better passivation and formation of more thick TiO2 layer. It has been shown that severe plastic deformation not only improves mechanical properties but also preserves corrosion stability of Ti-implants.