XPS investigation of TiO containing diamond-like carbon films

One of the widely used materials for medical implants is titanium, because it readily forms a passivation layer of titanium dioxide which is known to be of excellent biocompatibility. However, under mechanical loads this passivation layer may locally be removed resulting in a black residue of TiO2 particles around the implant. Hard diamond-like carbon (DLC) coatings on the other hand are known to be biocompatible and to have excellent mechanical and chemical stability. A combination of the two materials in the form of TiO containing DLC coatings is expected to show further improvements of the bio-mechanical properties of medical implants. In this paper we present X-ray photoelectron spectroscopy investigations of TiO containing amorphous hydrogenated carbon films. These films are produced by r.f.-plasma chemical vapor deposition using mixtures of acetylene and titanium(IV) ethoxide as feed gases. The chemical states of the different elements in as-deposited tiO DLC films are analyzed.