Fabrication and properties of Ti(C,N) based cermets reinforced by nano-CBN particles

Titanium carbontride (Ti(C,N)) based cermets with and without nano-cubic boron nitride (CBN) particles were prepared by microwave sintering in argon and nitrogen environment, respectively. Two kinds of core–rim microstructure, black core–grey rim and white core–grey rim, are shown in the cermets by scanning electron microscopy (SEM) in combination with energy dispersive X-ray analysis (EDX). It is found that, for the cermet with 1.5% nano-CBN particles sintered at 1500 °C for 30 min in argon, its transverse rupture strength (TRS) and hardness are improved to about 25.9% and 1.4%, respectively. The SEM analysis shows that the inhibition effect of nano-CBN particles on the dissolution of Ti(C,N) is weakened with the increase of content of nano-CBN particles. Moreover, for the cermet sintered in argon reinforced by 1.5% nano-CBN particles, more fine black core–grey rims are found in the microstructure compared to the others. For the material sintered in nitrogen, its microstructure accompanied with many white core–grey rims in number and big black core and thin outer rim in size, results in high hardness and low TRS.