Characterization of TiO2 films made by anodic oxidation on Ti-6Al-4V

VERA, M. L.; ARES, A. E.; ROSENBERGER, M. R.; LAMAS, D. G; SCHVEZOV, C.E.

Campinas

Otro; 20º Reunión Anual de Usuarios Laboratorio Nacional de Luz Sincrotron (LNLS); 2010

Laboratorio Nacional de Luz Sincrotron

The Ti-6Al-4V alloy is widely used as a structural material due to its excellent mechanical and corrosion resistant properties. At present they are also used in mechanical prosthetic devices for human implants due to the excellent biocompatibility. The bio and chemical properties of titanium alloys are known to be associated to the formation of TiO2 on the surface which occurs naturally. Oxide films in metals can also be produced by anodic oxidation, resulting in films which may be thicker and denser than the natural oxides.In this work TiO2 films on Ti-6Al-4V substrates were produced by anodic oxidation, using a H2SO4 1 M solution as electrolyte at different voltages (from 10V to 70V). Thickness and phase composition of the films were determined by X-ray reflectometry and X-ray diffraction, respectively. These experiments were carried out at the D12A-XRD1 beamline of the LNLS.The results of the influence of voltage on color, thickness, morphology and crystalline structure of the oxides are presented which are necessary to analyze for the production of coatings for biomedical applications.TiO2 films of different colors were obtained, with thickness ranging from 20 to 200 nm depending on the applied voltage. Relationships among voltage, color and thickness were confirmed. The film roughness is of the order of the substrate roughness and it increases with the applied voltage.The oxide layers produced at low voltages up to 50V are smooth and amorphous. A spark discharge occurs, at voltages larger than 60V, producing porous and crystalline (anatase and rutile) coatings. Each of these morphologies and structures of the coatings are suitable to different biomedical applications and devices.