Spark plasma sinterability of TiC ceramics with different nitride additives

Abstract

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 HV0.1 kg) was associated with the monolithic sample, followed by the TiC-AlN ceramic, at 3050 HV0.1 kg, while the lowest hardness of 2649 HV0.1 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.