Tribocorrosion-Resistant Ti40Nb-TiN Composites Having TiO₂-Based Nanotubular Surfaces

A novel multifunctional material was developed by hard TiN particle reinforcement addition to a β-type Ti40Nb alloy, followed by surface functionalization, yielding the formation of a nanotubular layer. Corrosion and tribocorrosion behaviors were investigated in a phosphate-buffered saline solution at body temperature. The results revealed that the Ti40Nb-TiN composites presented similar i_pass and E₍ values together with relatively similar R_ox and C_ox. However, its tribocorrosion resistance drastically improved (wear volume is almost 15 times lower than an unreinforced alloy) as a consequence of the load-carrying effect given by the reinforcement phases. The corrosion and tribocorrosion behaviors were further improved through surface functionalization as observed by significantly lower i_pass and higher R_ox values and almost undetectable wear volume loss from tribocorrosion tests due to the formation of a well-adhered anatase-rutile TiO₂-based nanotubular layer.