Fabrication of one-dimensional textured Si3N4-based ceramics with high hardness and toughness by low temperature hot extrusion

Abstract

Aiming to achieve silicon nitride (Si3N4) ceramics with high hardness and high toughness, one-dimensional textured Si3N4-based ceramics, with and without 0.5 vol% ZrB2 additive, were prepared using spark plasma sintering combined with hot extrusion at temperatures of 1600 °C and 1800 °C. One-dimensional texture (fI = 0.89) was achieved at a hot extrusion temperature of 1600 °C for the Si3N4 ceramic with the introduction of 0.5 vol% ZrB2. The fracture toughness (7.49 ± 0.47 MPa m1/2) closely approached that of the Si3N4 sample processed at the hot extrusion temperature of 1800 °C (7.95 ± 0.27 MPa m1/2), while the hardness (18.55 ± 0.18 GPa) was significantly higher than that of the Si3N4 sample processed at a hot extrusion temperature of 1800 °C (16.48 ± 0.20 GPa). It was demonstrated that one-dimensional textured Si3N4-based ceramics with high hardness and toughness can be prepared by the introduction of ZrB2 combined with low temperature hot extrusion.