Spark plasma sinterability of TiC ceramics with different nitride additives

This research aimed to assess the effect of various nitride additives, i.e., AlN, hexagonal BN, Si₃N₄, TiN, and ZrN, on the sinterability, microstructure, and mechanical-physical characteristics of TiC-based materials. All ceramics were sintered at the same sintering conditions using the spark plasma sintering (SPS) process. A relative density over 100% was secured by introducing 5 wt% AlN to the TiC matrix. By contrast, the Si₃N₄ additive had the most detrimental influence on the sinterability of TiC, resulting in a relative density of around 90.4%. Both ZrN and Si₃N₄ additives were fully consumed over the SPS route, contributing to the in-situ formation of (ZrC + TiN), and SiC ingredients, respectively. Additionally, the finest microstructure was obtained by using BN as an additive. The best flexural strength (688 MPa) was secured for the TiC-AlN sample, while the lowest (219 MPa) was related to the TiC-Si₃N₄ composite. Considering the hardness values, the highest number (3128 HV_{0.1 kg}) was associated with the monolithic sample, followed by the TiC-AlN ceramic, at 3050 HV_{0.1 kg}, while the lowest hardness of 2649 HV_{0.1 kg} was attained for the TiC-ZrN composite. Ultimately, both BN and AlN additives enhanced the thermal conductivity of TiC, reaching values of 18.6 and 21.9 W/mK, respectively.