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 ∼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. [Display omitted] • Amorphous carbon coating with and without hydrogen were deposited on WC-based cermet for tribocorrosion comparison. • a-C:H duplex coating presented the excellent tribocorrosion inhibition properties at lower load. • Poor toughness of a-C:H duplex coating caused the catastrophic delamination at higher load in chloride solution. • a-C coated WC cermet behaved the long-term tribocorrosion resistance under heavy friction due to graphitic shearing. [ABSTRACT FROM AUTHOR]