Effect Of Nbc On The Microstructure, Mechanical Properties, And Oxidation Resistance Of Ti(C,N)-Based Cermets

A comprehensive investigation of the effects of NbC on the microstructure and properties of Ti(C,N)-based cermets has been performed. Cermet samples were obtained via liquid-phase sintering under the guidance of thermodynamic calculations, and the amount of NbC was varied. The results showed that when the NbC content exceeded 12 wt.%, a hard phase with an NbC core appeared due to the lattice mismatch between the core and rim. NbC was not completely consumed by dissolution and precipitation, causing it to form a residual NbC core. As the NbC content increased, the grain size was refined, and the hardness of the cermet increased, but the fracture toughness decreased. When NbC was introduced into the cermet, a relatively dense protective layer was formed on the surface during oxidation, which restricted the diffusion of oxygen and improved the oxidation resistance of the cermet.