Equiaxed β–Si₃N₄ ceramics prepared by rapid reaction‐bonding and post‐sintering using TiO₂–Y₂O₃–Al₂O₃ additives

Abstract

Sintered reaction‐bonded Si3N4 ceramics with equiaxed microstructure were prepared with TiO2–Y2O3–Al2O3 additions by rapid nitridation at 1400°C for 2 hours and subsequent post‐sintering at 1850°C for 2 hours under N2 pressure of 3 MPa. It was found that α–Si3N4, β–Si3N4, Si2N2O, and TiN phases were formed by rapid nitridation of Si powders with single TiO2 additives. However, the combination of TiO2 and Y2O3–Al2O3 additives led to the formation of 100% β–Si3N4 phase from the nitridation of Si powders at such low temperature (1400°C), and the removal of Si2N2O phase. As a result, dense β–Si3N4 ceramics with equiaxed microstructure were obtained after post‐sintering at high temperature.

Influence of MXene (Ti3C2) Phase Addition on the Microstructure and Mechanical Properties of Silicon Nitride Ceramics

“…This is the opposite of what is found in the literature. Wu et al [33] investigated the effect of TiO 2 and TiO 2 /ZrO 2 /Y 2 O 3 addition to Si 3 N 4 on the formation of the Si 2 N 2 O phase. They showed that Si 2 N 2 O does not form in ceramics with oxide sintering activators.…”