摘要
以分子结构单元为[Si H2NH]n的全氢聚硅氮烷作先驱体,采用聚合物浸渍裂解法制备了三维石英织物增强氮化硅基复合材料(3DSi O2f/Si3N4)。研究了复合材料的致密化工艺与力学性能。结果表明:全氢聚硅氮烷与石英纤维润湿性好,浸渍效率高,陶瓷产率高;经5个浸渍裂解周期后复合材料密度达1.96g/cm3,孔隙率为10.9%,复合材料室温弯曲强度为33.5MPa,弹性模量为16.3GPa。由断口形貌看出:材料呈现脆性断裂,无纤维拔出现象,纤维与基体发生了较强的界面结合,基体内部和纤维表面均出现微裂纹。界面结合过强是导致3D Si O2f/Si3N4复合材料力学性能不佳的主要原因。
A 3 -dimensional silica fiber fabric reinforced silicon nitride composite was prepared by the polymer impregnation pyrolysis method using a preceramic polymer named perhydropolysilazane （PHPS） with the main backbone [SiH2 NH]n, as precursor. The densification behavior and mechanical properties of the composite were investigated. The results indicate that due to the good wettability of PHPS with silica fibers and high ceramic yield, the density of the composite reaches 1.96 g/cm^3 after five impregnation- pyrolysis cycles, with a porosity of 10.9 %. The flexural strength of the composite at room temperature is 33.5 MPa and the elastic modulus is 16.3 GPa. The morphology for the fracture surface of the composite shows that the composite exhibits a brittle fracture without fiber pull-out, and there is a strong bonding between the fiber and matrix interface. Micro-cracks are found in the matrix and on the surface of the fibers. The excessively strong bonding of the fiber/matrix interface probably result in the low mechanical properties of the composite.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2005年第12期1527-1530,共4页
Journal of The Chinese Ceramic Society
基金
国防预研资助项目。~~
关键词
全氢聚硅氮烷
聚合物浸渍裂解
石英织物
氮化硅
复合材料
致密化
力学性能
perhydropolysilazane
polymer impregnation pyrolysis
silica fiber fabric
silicon nitride
composite
densification
mechanical property
