A novel spark plasma sintered TiC–ZrN–C composite with enhanced flexural strength

Novel TiC-based composites were produced by incorporating ZrN and carbon black additives to improve their flexural strength. Spark plasma sintering method at 1900 °C was implemented to fabricate the designed composites; i.e., monolithic TiC, TiC-5 wt% carbon black, TiC-5 wt% ZrN, and TiC-5 wt% carbon black-5 wt% ZrN. Carbon black enhanced the sintering behavior of TiC remarkably, whereas the introduction of ZrN altered the composition of the matrix. The applied ZrN and its inevitable oxide phase proportion (ZrO₂) participated in the in-situ formation of ZrC and TiN compounds. Although ZrC was mainly entrapped in the carbonaceous phase, the remaining ZrN and TiN could be dissolved in the TiC_x matrix, forming (Ti,Zr) (C,N) solid solution. As the mobility of dislocations is not plausible in the solid solution, TiC–ZrN-carbon black composite represented a higher flexural strength (741 MPa) than TiC-carbon black (658 MPa) counterpart. Furthermore, remarkable thermal conductivity (25.1 W/mK) and hardness (3233 HV_{0.1 kg}) were achieved for the ceramic containing carbon black.