Effect of MoC Addition on the Tribological Behavior of Ti(C,N)-Based Cermets.

Due to the excellent properties of Ti (C,N)-based ceramics, such as high hardness, excellent wear resistance, exceptional thermal deformation resistance, and sound chemical stability, they have been widely used in cutting tools or molds. Thus, revealing their tribological behavior against hard materials is of great significance. Some studies have reported the tribological behavior of Ti(C,N)-based cermets and hard cermets, but so far, the effects of MoC additions on the frictional properties of Ti(C,N)-based cermets are still unclear. In this study, Ti(C,N)-10WC-1CrC-5Co-10Ni-x MoC cermets (x = 4, 6, 8, 10 and 12 wt.%) were sintered using a vacuum hot-pressing furnace. Furthermore, the core-rim morphologies of the sintered samples were observed in SEM images. Then, the wear resistance of the cermets was studied against a SiN ball at a 50 N load using the fretting wear test. Finally, the wear mechanism was characterized using a combination of SEM, EDS and XPS. The experimental results indicated that the wear mechanisms of the cermets were mainly abrasive wear, adhesive wear, and the formation of an oxide film. As the content of MoC increased from 4 wt.% to 12 wt.%, the friction coefficient and wear volume had a variation law of first decreasing and then decreasing, and reached minimum values at 6 wt.% and 12 wt.%, and the lowest friction coefficient and wear rate were 0.49 and 0.9 × 10 mm/Nm, respectively. The 6 wt.% MoC greatly improved the hardness and fracture toughness of the cermet, while the 12 wt.% MoC promoted the formation of an oxide film and protected the friction surface. The cermet with 6 wt.% MoC is recommended because it has comprehensive advantages in terms of its mechanical properties, tribological properties, and cost.