Comparison of tribological and corrosion behaviors of Cp Ti coated with the TiO₂/graphite coating and nitrided TiO₂/graphite coating

The TiO₂/graphite coatings were fabricated by micro arc oxidation (MAO) process combined with or without plasma nitriding to improve the tribological and anti-corrosion performances of the Cp Ti. The microstructure and composition of the coatings were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. The tribological and corrosion behaviors were evaluated by the friction test and electrochemical test, respectively. Results show that the nitrided TiO₂/graphite coating exhibits relatively smooth surface with less porous structure. Its friction coefficient, wear rate under dry sliding condition and corrosion current density in artificial seawater are lower, compared to those of the TiO₂/graphite coating, indicating that it has perfect tribological property and corrosion resistance. - Highlights: • The TiO₂/graphite MAO coating has been treated by plasma nitriding successfully. • The nitrided coating exhibites relatively smooth surface with less porous structure. • The plasma nitriding is useful to improve the tribological and anti-corrosion properties of MAO coating.