Draft tube using carbon/carbon/silicon carbide composite material and preparation method of draft tube

The invention discloses a draft tube using carbon/carbon/silicon carbide composite material, with simple production process and resistance to erosion of silicon vapour, and a preparation method of the draft tube. The preparation method of the draft tube is characterized by comprising the steps of carrying out the chemical vapour infiltration on the carbon fibre preform of the draft tube to to densify pyrolytic carbon and silicon carbide alternatively or perform caballing to the pyrolytic carbon and the silicon carbide, mechanically machining, and purifying to obtain the product. The density of the draft tube is between 1.3g/cm and 2.5g/cm , the flexural strength of the draft tube is more than or equal to 300MPa, and the fracture toughness of the draft tube is more than or equal to 15MPa.m . According to the draft tube and the preparation method provided by the invention, the erosion of the silicon vapour on the core carbon fibre of the carbon/carbon/silicon carbide composite material can be effectively inhibited. The flexural strength of the prepared carbon/carbon/silicon carbide composite material is more than 300MPa and is 2-5 times of that of the carbon/carbon composite material; the fracture toughness of the carbon/carbon/silicon carbide composite material is more than or equal to 15MPa.m ; the resistance of the carbon/carbon/silicon carbide composite materialto the erosion of the silicon vapour is increased by 5-10 times compared with that of the carbon/carbon composite material; the service life of the draft tube is greatly prolonged; and meanwhile, thehigher strength of the draft tube is beneficial to the improvement of the safety of the thermal field.