Comparative study on tribocorrosion behavior of hydrogenated/hydrogen-free amorphous carbon coated WC-based cermet in 3.5 wt% NaCl solution

In this work, the tribocorrosion performance of hydrogenated and hydrogen-free diamond-like carbon (DLC) coated thermal sprayed WC-based cermet/carbide were investigated comparatively. The results showed that, regardless of hydrogen containing, both coatings demonstrated the improvement of anti-tribocorrosion capability of WC-based cermet in 3.5 wt% NaCl solution, by suppressing the corrosion of Ni-based binder phases. Particularly, the hydrogenated DLC coating presented the better tribocorrosion resistance under low load due to the high hardness and excellent corrosion resistance, but it suffered from the catastrophic delamination and protective degradation at heavy load arisen from the high brittleness and large residual stress. In contrast, the hydrogen-free DLC duplex coating exhibited a low COF of similar to 0.06 under higher load (10 N) with long time friction (12 h), because of its gradually shearing characteristic. This work provides theoretical basis and design principles for DLC combinations with remarkable corrosion inhibition used in harsh marines.