Abstract—

Si₃N₄/TiN ceramic composites have been prepared by hot pressing in a nitrogen atmosphere using fine Si₃N₄ and Ti powders and CaO–Al₂O₃ sintering aids and investigated. The results demonstrate that hot pressing was accompanied by titanium nitridation, yielding titanium nitride with the composition TiN_0.9. Reaction between silicon nitride and the sintering aid led to the formation of a Ca-α-SiAlON with the composition Ca_0.67(Si₁₀Al₂)(N_15.3O_0.7). In addition to the major phases, calcium aluminosilicate with the composition Ca₃Al₂Si₃O₁₂ was identified. Increasing the percentage of titanium nitride in the composites prepared at a temperature of 1650°C led to an increase in their density and Vickers microhardness: from 3.18 ± 0.03 to 4.33 ± 0.03 g/cm³ and from 17 ± 1.1 to 29.4 ± 0.9 GPa, respectively.