Effects of TiN content on the properties of hot pressed TiB2-SiC ceramics

This research intended to study the impacts of different contents of the TiN additive on the mechanical properties and microstructural features of the TiB2-SiC-based composites. Three different samples of TiB2-15 vol% SiC- x vol% TiN (x = 0, 3.5, and 7) were produced by hot-pressing at 2000 C under 35 MPa for 120 min. Thanks to advancement of some reactions among the TiB2 surface oxides and the SiC reinforcement, two in-situ phases of TiC and SiO2 were produced during the sintering. Nevertheless, the TiN incorporation resulted in generating another in-situ compound (TiC0.3N0.7) in the relevant as-sintered ceramics. Moreover, introducing TiN significantly refined the microstructure of the composites, leading to higher mechanical characteristics. Finally, the highest flexural strength (781 MPa) and Vickers hardness (27.1 GPa) values were attained for the sample introduced by 7 vol% TiN.