Effect of Mo2C Addition on the Tribological Behavior of Ti(C,N)-Based Cermets

Abstract

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 Mo2C additions on the frictional properties of Ti(C,N)-based cermets are still unclear. In this study, Ti(C,N)-10WC-1Cr3C2-5Co-10Ni-x Mo2C 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 Si3N4 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 Mo2C 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 × 10−6 mm3/Nm, respectively. The 6 wt.% Mo2C greatly improved the hardness and fracture toughness of the cermet, while the 12 wt.% Mo2C promoted the formation of an oxide film and protected the friction surface. The cermet with 6 wt.% Mo2C is recommended because it has comprehensive advantages in terms of its mechanical properties, tribological properties, and cost.

A Review of Research Progress on Ti(C,N)-Based Cermet Binder by Intermetallic Compounds and High-Entropy Alloys

“…Ti(C,N)-based cermet is a kind of metal-ceramic material prepared by the powder metallurgy method using TiC, TiN, and Ti(C,N) as the matrix composition [1][2][3][4], the titanium carbide structure, as shown in Figure 1, Fe-Co-Ni as the binder [5][6][7][8], and other transition metal carbides [9][10][11][12]. Because of its high hardness, excellent wear resistance, low coefficient of friction, and good chemical stability, Ti(C,N)-based cermet has become an important alternative material to cemented carbide and is widely used in cutting and grinding tools [13][14][15][16][17].…”

Effect of Si3N4 Additive on Microstructure and Mechanical Properties of Ti(C,N)-Based Cermet Cutting Tools

“…They can influence the solid solution reaction, grain growth, and core/rim structure of Ti(C,N)-based cermets, which will cause a change in the material’s mechanical features [ 14 ]. The addition of both WC and Mo 2 C can enhance the wettability between the core and metallic phase and improve sintering properties of Ti(C,N)-based cermets to obtain greater performance during dry machining [ 15 , 16 , 17 ]. Furthermore, for boosting the thermal shock resistance and hot hardness, NbC plays a crucial role in this issue [ 13 , 18 ].…”