Effect of HfC addition on microstructure of Ti(CN)–Ni cermet system

Abstract

Ti(CN) based cermets have a core/shell microstructure, which gives rise to outstanding mechanical properties and chemical stability for cutting tool applications. The HfC content and C/N ratio in Ti(C_1-x N_x ) were varied in order to investigate the effect of HfC addition on the microstructure of Ti(C_1-x N_x )–Ni systems. The presence of HfC in the solid solution, (Ti,Hf)C, was found to cause the surface energy to be more anisotropic in the presence of liquid Ni. A phase separation of (Ti,Hf)C and (Hf,Ti)C was noted when >20 wt-%HfC was added to TiC–HfC–Ni. In addition, the Ti(C_0·3 N_0·7 ) based system showed the lowest coarsening for all sintering times of the various Ti(C_1-x N_x ) systems examined. This study focuses on the role of various Ti(CN) and HfC cermets and how they affect the coarsening of microstructures.