Synthesis and sintering properties of silica-coated titanium nitride particles

[Display omitted] •Silica-coated TiN (TiN/SiO2) particles were fabricated using a sol–gel method.•The SiO2 coating densified the sintered bodies fabricated using the TiN/SiO2 particles.•The NaOH catalyst densified the sintered bodies fabricated using TiN/SiO2 particles.•The hardness of the sintered body fabricated using TiN/SiO2 particles synthesized over NaOH was high.•The hardness of the sintered bodies increased owing to an increase in densification. Herein, we synthesized silica-coated titanium nitride (TiN/SiO2) particles via a sol–gel method and evaluated the hardness of the sintered bodies fabricated using the as-fabricated TiN/SiO2 particles. Commercially available micron-sized TiN particles were dispersed in a water–ethanol solution at 35 °C and then coated with SiO2 using a sol–gel method, tetraethyl orthosilicate (TEOS), and base catalysts. TiN/SiO2 particles with small specific surface areas owing to the presence of few micropores in their structure were obtained using NaOH as the base catalyst. The Vickers hardnesses of TiN, a mixture of TiN and SiO2 (TiN–SiO2), TiN/SiO2 fabricated using an ammonia solution as the base catalyst (TiN/SiO2A), and TiN/SiO2 fabricated using NaOH as the base catalyst (TiN/SiO2S) increased as follows: TiN (6.35 × 102 Hv)