The preparation method of ultra-fine tow silicon carbide fibre

The present invention provides a kind of preparation method of ultra-fine tow silicon carbide fibre, raw material will be used as using Polycarbosilane (PCS), from the small silk number spinneret that hole count is less than 200, continuous P CS fibers are made by melt spinning, continuous P CS fibers are subjected to radiation annealing processing and are changed into PCS fusion-free fibres, by PCS fusion-free fibres by pre-burning under more than 1000 DEG C inert atmospheres, then by being burnt eventually under more than 1400 DEG C inert atmospheres, prepare the SiC fibers of ultra-fine tow.The ultra-fine tow silicon carbide fibre prepared, on the basis of 11 12 μm of fibre diameter is ensured, number of fiber is controlled below 200.