Synthesis and sintering properties of silica-coated titanium nitride particles

Herein, we synthesized silica-coated titanium nitride (TiN/SiO2) particles via a sol-gel method and eval-uated 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 degrees 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 x 102 Hv) < TiN-SiO2 (1.01 x 103 Hv) < TiN/SiO2A (1.11 x 103 Hv) < TiN/SiO2S (1.15 x 103 Hv). In sum-mary, the SiO2 shell served as a sintering aid, and the NaOH catalyst densified the sintered body and improved its hardness. (c) 2023 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Automated summary

Silica-coated titanium nitride (TiN/SiO2) particles were synthesized using a sol-gel method and the hardness of the sintered bodies fabricated with these particles was evaluated. The presence of few micropores in the TiN/SiO2 structure resulted in particles with small specific surface areas. The Vickers hardness increased in the order: TiN < TiN-SiO2 < TiN/SiO2A < TiN/SiO2S. The SiO2 shell acted as a sintering aid and the NaOH catalyst improved the density and hardness of the sintered body.