包覆成孔剂法制备高性能多孔氮化硅陶瓷工艺

为了制备高强度且分布均匀的氮化硅陶瓷,采用包覆成孔剂法改进普通添加成孔剂的方法,常压烧结氮化硅多孔陶瓷,采用阿基米德法、三点弯曲法分别测试材料的孔隙率及抗弯强度,用扫描电镜和光学放大镜对氮化硅多孔陶瓷显微结构和表观结构进行研究.结果表明,添加包覆过的成孔剂强度比添加未包覆的成孔剂强度高,孔隙率为50%时,强度增加近一倍.强度的提高归因于特殊的微观结构,即气孔的均匀分布和孔与孔之间相间隔分布.

Preparation of porous silicon nitride ceramics by coated pore-forming agent method

Coated pore-forming agent method was introduced to the modification of the ordinary pore-forming method to prepare porous silicon nitride ceramics with high strength and uniform distribution. The porosity and flexural strength of the ceramics were measured. SEM and optical magnifier were used to investigate the morphology and microstructure of the prepared ceramics. Results show that the flexural strength of these porous silicon nitride ceramics is much higher than that of those without coating process treatment. When the porosity is 50% ,the flexural strength is increased by almost 100% . The enhancement of strength is ascribed to the uniform distribution of spherical pores and the partition of these pores.