Hardness and corrosion protection enhancement behaviour of surgical implant surfaces treated with ceramic thin films

Abstract

Covalent thin films like TiN and other hard coatings are widely used for tribological and corrosion protection of surfaces. The use of tools covered in thin films in mechanical and chemical industries have increased strongly in the past few years. However, this surface treatment is not commercially applied to surgical implants such as a femoral prosthesis, which is submitted to strong wear and corrosion attack. Ti–6Al–4V ELI alloy together with stainless steel are still the main materials used for medical applications because of their corrosion resistance and biocompatibility. To improve the poor surface hardness and wear resistance of these implants, titanium nitride and (Ti–6Al–4V)N thin films were deposited on the mobile surface. To obtain a good coating–surface adhesion, the protective films were deposited using magnetron sputtering equipment and all samples were cleaned by means of plasma etching in an argon–nitrogen atmosphere. The layers produced have been characterised in terms of phase formation by X-ray diffraction, the composition and depth profile were studied by means of Rutherford backscattering, X-ray photon spectroscopy and energy dispersive spectroscopy (EDS), the hardness was checked using a nano-hardness tester and corrosion protection enhancement was tested using cyclic voltammetry equipment.