Highly flexible and strong SiC fibre mats prepared by electrospinning and hot-drawing

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.