“…This choice is motivated by titanium appropriate properties such as low density, high strength to weight ratio, good corrosion resistance, and above all, biocompatibility which is conferred by the thin and compact oxide (TiO 2 ) spontaneously formed at its surface in the presence of oxygen [1][2][3]. However, in some applications (in ankle and hip joints, for instance) superior mechanical wear and, mainly, wear-corrosion resistance are required, but not provided by those metals [4,5]. To extend the use of titanium to situations where superior resistance is required, researchers have been working to improve the surface properties of titanium and its alloys through mechanical, chemical, thermo-chemical processes and/or coating deposition [6][7][8][9][10].…”