Microstructure and mechanical properties of Ti (C, N) based cermets reinforced with different ceramic particles processed by spark plasma sintering

The addition effect of different ceramic particles such as TiB2, TiN and nano-Si3N4 on the microstructure and mechanical properties of TiCN-WC-Co-Cr3C2 based cermets, which are prepared by spark plasma sintering, was studied. Microstructural characterization of the cermets was done by scanning electron microscope. X-ray diffraction was performed to study the crystal structures. Mechanical properties such as hardness and fracture toughness were measured for the different developed cermets. The hardness and fracture toughness of the TiCN-WC-Co-Cr3C2 cermets without TiN, TiB2, and nano-Si3N4 were 8.4 GPa and 3.4 MPa m1/2, respectively. It was found that 5 wt% TiB2 addition alone improved the corresponding hardness and fracture toughness to 19.2 GPa and 6.9 MPa m1/2, respectively. The addition of 5 wt% TiN, improved the hardness and fracture toughness to 16.7 GPa and 6.9 MPa m1/2, respectively. With the combination of 5 wt% TiN and 5 wt% TiB2, the hardness and fracture toughness were improved to 15.5 GPa and 6.6 MPa m1/2, respectively. But, the addition of 5 wt% Si3N4 showed a balanced improvement in both hardness (17.6 GPa) and toughness (6.9 MPa m1/2). Fracture toughness did not change much for all the above cermets with different ceramic inclusions.