Preparation and Study of Porous Si~3N4 Ceramics with High Strength by Gelcasting

Porous Si3N4 ceramics with high strength, uniform structure and relative high porosity were obtained by gelcasting. The mechanical performances and micro-structure of the porous Si3N4 ceramics were studied and the reasons were discussed. It was showed that using proper techniques, green bodies with high strength, uniform structure and good machining proparey could be got. Results show that the sintered porous Si3N4 ceramics have strength more than 150MPa and porosity up to 50%. SEM shows that porous are formed by the banding-up of pillar β-Si3N4. The uniform porous distribution and pillar structure are the main reasons for good mechanical performances.