Equiaxed β–Si3N4 ceramics prepared by rapid reaction‐bonding and post‐sintering using TiO2–Y2O3–Al2O3 additives. Issue 12 (8th August 2017) - Wu, Li‐Xiang
Abstract: Sintered reaction‐bonded Si3 N4 ceramics with equiaxed microstructure were prepared with TiO2 –Y2 O3 –Al2 O3 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–Si3 N4, β–Si3 N4, Si2 N2 O, and TiN phases were formed by rapid nitridation of Si powders with single TiO2 additives. However, the combination of TiO2 and Y2 O3 –Al2 O3 additives led to the formation of 100% β–Si3 N4 phase from the nitridation of Si powders at such low temperature (1400°C), and the removal of Si2 N2 O phase. As a result, dense β–Si3 N4 ceramics with equiaxed microstructure were obtained after post‐sintering at high temperature.