Role of TiC nanocrystalline and interface of TiC and amorphous carbon on corrosion mechanism of titanium doped diamond-like carbon films: Exploration by experimental and first principle calculation

Abstract The corrosion mechanism of Titanium doped Diamond-like carbon (Ti-DLC) films was investigated by electrochemical tests and first-principle calculations. Potentiodynamic polarization curves and Electrochemical impedance spectroscopy (EIS) show that the Ti-DLC films exhibit a poor corrosion resistance than that of pure DLC film in 3.5 wt% NaCl solution. The formed TiC nanocrystalline in Ti-DLC film reduce the migration barrier and energy of Cl atom permeation in the film, which causes a lower total system energy change of the crystal plane TiC, interface structure of TiC and amorphous carbon (TiC/a-C) than that of pure DLC film, and then accelerates the corrosion failure of the Ti-DLC film.