Super-thick diamond-like carbon (DLC) film is a potential protective coating in corrosive environments. In the present work, three kinds of DLC films whose thickness and modulation periods are 4μm and 3,21μm and 17 and 21μm and 7, respectively, were fabricated on stainless steel. The effect of different thickness and modulation periods on corrosion and tribocorrosion behavior of the DLC-coating stainless steel was investigated in 3.5wt% NaCl aqueous solution by a ball-on-flat tribometer equipped with a three-electrode electrochemical cell. The DLC-coating stainless steel served as a working electrode, and its OCP and potentiody-namic polarization were monitored before and during rubbing. The wear–corrosion mechanism of the DLC films was investigated by SEM. The results showed that the increasing thickness can prolong significantly lifetime of DLC films in NaCl aqueous solution.
In particular, the modulation period has a significant impact on the tribocorrosion resistance of the DLC super-thick films. The study suggested that the increasing thickness of compressive stress layer could suppress film damage by reducing crack propagation rate. Thus, the super-thick DLC film with thickness of 21μm and 7 periods presented the best tribocorrosion resistance among all studied films.