A novel biomedical TiN-embedded TiO2 nanotubes composite coating with remarkable mechanical properties, corrosion, tribocorrosion resistance, and antibacterial activity

Tribocorrosion is a severe problem in dental implants, artificial joints, and other implants, and it will affect the long-term safety of the implants. To improve the deficiencies of titanium alloys, we combined physical vapor deposition technology and anodic oxidation to prepare TiN to embed TiO2 nanotube composite coatings (NTNTs-TiN). Results show that the hardness of the NTNTs-TiN composite coatings reaches 33.2 +/- 0.6 GPa, and the grains of the composite coatings were further refined. The NTNTs-TiN coating has the smallest average coeffi-cient of friction (0.22) during tribocorrosion. The tribocorrosion resistance of NTNTs-TiN coating in SBF is increased by-44 and-2 times compared with Ti6Al4V alloy and TiN coating, respectively. The capillarity effect of the lower contact angle of NTNTs-TiN can form a continuous water-lubrication film at the interface between the counter-ball and coating and produce a lubrication film composed of Ca, Mg, and P, which reduces the coefficient of friction significantly. The NTNTs/TiN composite coating exhibits the best synergistic effect of wear and corrosion. In addition, the NTNTs-TiN coating also exhibits excellent antimicrobial and corrosion properties, which provides a new solution for the long-term safe use of implants in the human body.