先驱体浸渍-裂解法制备SiBN纤维增强SiBN陶瓷基复合材料

连续纤维增强氮化物陶瓷基复合材料是耐高温透波材料的主要发展方向,纤维是目前制约耐高温透波复合材料发展的关键,而SiBN陶瓷纤维是一种兼具耐高温、透波、承载的新型陶瓷纤维。以聚硅氮烷为陶瓷先驱体,以SiBN连续陶瓷纤维为增强体,采用先驱体浸渍-裂解法制备了SiBN陶瓷纤维增强SiBN陶瓷基复合材料,研究了复合材料的热膨胀特性、力学性能、断裂模式以及微观结构。结果表明:SiBN陶瓷纤维增强SiBN陶瓷基复合材料呈现明显的脆性断裂特征,复合材料的弯曲强度和拉伸强度分别为88.52 MPa和6.6 MPa,纤维的力学性能仍有待于提高。

Preparation of SiBN fiber reinforced SiBN ceramic matrix composites by precursor infiltration-pyrolysis method

Continuous fiber-reinforced nitride ceramic matrix composites are the main development direction of high-temperature wave-transparent materials, fiber is the pivotal issue which restrict the development of high-temperature wave-transparent composite materials, and SiBN ceramic fibers are a new kind of ceramic fibers which have excellent performances of high temperature resistance, wave transmission and mechanics. Polyborosilazane was used as ceramic precursor, and SiBN continuous fiber was used as reinforcement, SiBN fiber reinforced SiBN ceramic matrix composites were prepared by precursor infiltration-pyrolysis method. The thermal expansion properties, mechanical properties, fracture modes and microstructures of SiBN fiber reinforced SiBN ceramic matrix composites were investigated, and the preparation of new high-temperature wave-transparent ceramic matrix composites by precursor infiltration-pyrolysis was explored. The results show that the SiBN fiber reinforced SiBN ceramic matrix composites exhibits distinct brittle fracture characteristic, the bending strength and tensile strength of the composites are 88.52 MPa and 6.6 MPa respectively, which means the mechanical properties of the fiber still needs to be improved.