Abstract:Ti(Cx,N1-x)-based cermets are fabricated with different ratios of carbon to nitrogen. The effect of C/N ratio on the core-rim structures and properties of cermets was studied. The results indicate that Ti(C0.5,N0.5)-based cermets possess poor properties due to too many pores. With the increase of C/N ratio, the formation rate of white-core/gray-rims decreases, and the homogeneity of the microstructure is enhanced. Consequently, the Ti(C0.7,N0.3)-based cermets show excellent mechanical properties, but a spot of voids and low relative density. TiC-based cermets with excellent relative density and non-porosity can be achieved in the absence of N element, which have coarser grain compared with Ti(C0.7,N0.3)-based cermets. In order to achieve fine grains and high density microstructure, 0.25wt%Cr3C2-0.75wt%VC is introduced into the TiC-based cermets. Superior hardness, transverse rupture strength and toughness are achieved. In addition, 0.25wt%Cr3C2-0.75wt%VC is also added into the Ti(C0.7,N0.3)-based cermets, but its mechanical properties are lower than that of the Ti(C0.7,N0.3)-based cermets without 0.25wt%Cr3C2-0.75wt%VC addition, which is due to acute solid solution reaction of finer and reactive particles with Ti(C,N). The cutting and friction performances of Ti(Cx,N1-x)-based cermets with different C/N ratios were also investigated. The results show that the TiC-based cermets with 0.25wt%Cr3C2-0.75wt%VC exhibit the lowest coefficient of friction which is 0.15 at the room temperature, and the longest service life during high speed cutting at 1000 r/min.