ABSTRACT

Silicon carbide (SiC) fibres are widely used as promising reinforcement in ceramic matrix composites due to their excellent mechanical and thermal properties. In this work, sub-micrometer SiC fibres were prepared by electrospinning using polycarbosilane as the precursor, followed by curing in air and pyrolysing at high temperatures. The effect of the microstructure of SiC fibres on mechanical properties was investigated and the SiC fibre mats prepared at 1300°C for 2 h exhibited a mechanical strength of 184.5 ± 19.4 MPa. Hot-drawing was conducted on as-spun fibres during the curing process and the strength, Young’s modulus, and flexibility of SiC fibre mats were improved. The strength with a drawing ratio of 200% reaches 243.0 ± 17.5 MPa. The enhancement of mechanical strength after hot-drawing is mainly attributed to the reduced defects in fibres, improvement in the orientation of the precursor fibres as well as the alignment of the molecular chains in the precursor fibres.

摘要

碳化硅 (SiC) 纤维由于其优异的机械和热性能而被广泛用作陶瓷基复合材料的有前途的增强材料。在这项工作中，亚微米 SiC 纤维是通过使用聚碳硅烷作为前驱体进行静电纺丝，然后在空气中固化并在高温下热解制备的。研究了 SiC 纤维的微观结构对机械性能的影响，在 1300°C 下制备 2 小时的 SiC 纤维垫的机械强度为 184.5 ± 19.4 MPa。在固化过程中对初纺纤维进行热拉伸，提高了碳化硅纤维毡的强度、杨氏模量和柔韧性。拉伸比为200%时强度达到243.0±17.5MPa。热拉伸后机械强度的提高主要归因于纤维缺陷的减少，