Comparative study of β-Si 3N 4 powders prepared by SHS sintered by spark plasma sintering and hot pressing

Abstract

β-Si 3N 4 powders prepared by self-propagating high-temperature synthesis (SHS) with additions of Y 2O 3 and Al 2O 3 were sintered by spark plasma sintering (SPS). The densification, microstructure, and mechanical properties of Si 3N 4 ceramics prepared using this method were compared with those obtained by hot pressing process. Well densified Si 3N 4 ceramics with finer and homogeneous microstructure and better mechanical properties were obtained in the case of the SPS technique at 200°C lower than that of hot pressing. The microhardness is 15.72 GPa, the bending strength is 716.46 MPa, and the fracture toughness is 7.03 MPa·m ½.