Comparative study of β-Si₃N₄ powders prepared by SHS sintered by spark plasma sintering and hot pressing

β-Si₃N₄ powders prepared by self-propagating high-temperature synthesis (SHS) with additions of Y₂O₃ and Al₂O₃ were sintered by spark plasma sintering (SPS). The densification, microstructure, and mechanical properties of Si₃N₄ ceramics prepared using this method were compared with those obtained by hot pressing process. Well densified Si₃N₄ ceramics with finer and homogeneous microstructure and better mechanical properties were obtained in the case of the SPS technique at 200℃ 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^1/2.