▎ 摘　　要

NOVELTY - Preparation of graphene-modified carbon fiber-reinforced silicon carbide composite material involves placing surface-functionalized carbon fiber preform in impregnation solution, vacuum-immersing for 0.5-2 hours, removing impregnated carbon fiber, subjecting to hydrothermal chemical reduction reaction at 70-95 degrees C for 4-6 hours, obtaining multi-scale graphene-carbon fiber preform, depositing multi-scale graphene-carbon fiber preform on silicon carbide substrate by chemical vapor infiltration method and obtaining composite material. USE - Preparation of graphene-modified carbon fiber-reinforced silicon carbide composite material (claimed). ADVANTAGE - The method efficiently provides graphene-modified carbon fiber-reinforced silicon carbide composite material having high temperature resistance, wear resistance and electromagnetic shielding performance, by simple method. DETAILED DESCRIPTION - Preparation of graphene-modified carbon fiber-reinforced silicon carbide composite material involves adding a reducing agent to 1-10 mg/ml graphene oxide solution, obtaining impregnating solution such that the mass ratio of reducing agent with respect to graphene oxide is 1:1-1:10, ultrasonically cleaning carbon fiber preform using acetone, placing in high-concentration nitric acid at 85-95 degrees C for 1-4 hours, removing, subjecting to dialysis treatment using 5-40% ethanol aqueous solution for 24 hours or more, removing carbon fibers after drying at 40-65 degrees C, obtaining surface-functionalized carbon fiber preform, placing surface-functionalized carbon fiber preform in impregnation solution, vacuum-immersing for 0.5-2 hours, removing impregnated carbon fiber, subjecting to hydrothermal chemical reduction reaction at 70-95 degrees C for 4-6 hours, obtaining multi-scale graphene-carbon fiber preform, depositing multi-scale graphene-carbon fiber preform on silicon carbide substrate by chemical vapor infiltration method and obtaining composite material. The chemical vapor deposition of silicon carbide, is carried out by placing multi-scale graphene-carbon fiber preform in vapor deposition furnace, evacuating the furnace at 2-3 kPa, introducing inert gas as shielding gas at the flow rate of 200-800 mL/minute, increasing furnace temperature to 1000-1300 degrees C at the temperature rising rate of 5-10 degrees C/minute, introducing hydrogen at the flow rate of 100-300 ml/minute, introducing methyltrichlorosilane gas at the flow rate of 4-20 g/h, adjusting the furnace pressure as 2-8 kPa, carrying out deposition reaction for 20-120 hours, and cooling the temperature inside the furnace to room temperature.