Reduced Pressure Curing on Polycarbosilane Precursor for Synthesis of Silicon Carbide Fiber

Low pressure curing method with iodine vapor was used on low softening temperature polycarbosilane (PCS) precursor for fabrication of continuous SiC fiber at relatively low temperature. The low curing temperature can provide with a wide range of softening temperature PCS precursors, especially with low softening PCSs, which have a good spinnability, but many difficulties with conventional oxidation curing method. The low pressure curing method having the presence of iodine vapor have shown the more positive effect on pyrolysis with early stage crystallization of β-SiC at 1300 °C. Crystal size of β-SiC, cured at 0.008 kPa is around 2–3 nm larger than cured at 101 kPa. In addition, the higher tensile strength of SiC fiber at elevated temperature can be obtained at 0.008 kPa with a value of 2.1 GPa, compare to 1.3 GPa at 101 kPa of curing pressure condition.