Characterization of modified Ti6Al4V alloy after fretting-corrosion tests using near- field microscopy

Fretting wear and corrosion of Ti6Al4V alloys at the bone/implant stem interface produces the release of wear particles and corrosive ions from the stem into the surrounding tissue that can induce bone resorption. In this work, oxidation treatments at 500o and 700 oC for 1 h have been studied for increasing the friction-corrosion resistance at these interfaces. The friction-corrosion process of thermally treated Ti6Al4V discs against pins of cadaver bone were evaluated in bovine serum medium for 1 million cycles of loading at 4Hz with maximum contact pressures of 10 MPa. Cyclic displacement of 120 μm for pin-on-disk samples in a linear motion was applied. Samples were characterized, before and after the oxidation treatment, by atomic force microscopy (AFM), scanning Kelvin probe (SKP) and scanning electrochemical microscopy (SECM). The characterization of the Ti6Al4V samples showed the growth and the different morphology of the oxides as a consequence of the temperature. SKP and SECM revealed that the surface of oxidized samples had lower