Synthesis and consolidation of TiN/TiB2 ceramic composites via reactive spark plasma sintering

The simultaneous synthesis and densification of TiN/TiB2 ceramic composites via reactive spark plasma sintering (RSPS) was investigated. Different component ratios (TiH2/BN (TiN, B)) and heating rates (112.5–300 °C/min) were used to initiate the chemical reaction for TiN/TiB2 synthesis. The omit RSPS process was revealed to have three stages, which are described separately. The relationships between the RSPS conditions, the microstructure and the properties of sintered ceramic composites were established. A Vickers hardness of 16–25 GPa and a fracture toughness of 4–6.5 MPa m1/2 were measured for various compositions. Sintered ceramic composites containing 36 wt% TiB2 with the highest relative density of 97.4 ± 0.4% and an average grain size of 150–550 nm have been obtained.

Research highlights▶ The omit process of TiN/TiB2 consolidation consists of three stages. ▶ The formation of a nonstoichiometric TiN1−xCx (x = 0.1–0.3) phase instead TiN phase. ▶ The relative density of 97.4 ± 0.4% for composites containing 36 wt%TiB2 was obtained. ▶ The ceramic composites containing 36 wt% TiB2 has the most homogeneous nanostructure. ▶ A Vickers hardness of 16–25 GPa and a fracture toughness of 4–6.5 MPa m1/2.