A novel strategy for c-axis textured silicon nitride ceramics by hot extrusion

摘要

Highly c-axis textured beta-silicon nitride (beta-Si3N4) ceramic with fine grains was prepared by a new method of hot extrusion for the first time. The (002) pole figure on the section plane vertical to extruding direction showed a characteristic of center rotational symmetry. The average cline angle between elongated beta-Si3N4 grains and hot extruding direction was about 14.4 degrees. The degree of c-axis texturing by hot extrusion was comparable to that achieved by rotating magnetic field. The hardness and toughness anisotropy in different direction was apparent and relatively higher hardness was achieved in the present work mainly due to the finer grain size. Therefore, many different compositions of c-axis aligned Si3N4-based ceramics with tailored mechanical properties could be achieved by the strategy of hot extrusion.