▎ 摘　　要

NOVELTY - Preparing silicon carbide composite material, comprises (i) mixing silicon source, ethanol and water in a certain proportion, and stirring in a certain concentration of hydrochloric acid solution for 18-24 hours; (ii) slowly dropping aqueous ammonia into the hydrolysis solution of the silicon source while stirring, and adding the dispersion of the carbon source into the solution before the gel is formed, stirring slowly and adding a small amount of ammonia; (iii) placing the mixed gel in a refrigerator and transferring to a freeze dryer to obtain a dry gel, placing the dry gel in an alumina crucible, placing the whole crucible in a vacuum tube high-temperature furnace for reaction, and introducing in protective gas, storing at a certain temperature for 4 hours, cooling and taking out solid to room temperature naturally; (iv) allowing to stand the solid for 2 hours in a mixed solution of hydrofluoric acid and ionized water, and freeze-drying solid material removed from the solution. USE - The method is useful for preparing silicon carbide composite material. ADVANTAGE - The method is economical and environmentally friendly, has simple operation and technology, simple equipment, and high efficiency to obtain a composite material with high wave absorbing performance. DETAILED DESCRIPTION - Preparing silicon carbide composite material, comprises (i) mixing silicon source, ethanol and water in a certain proportion, and stirring in a certain concentration of hydrochloric acid solution for 18-24 hours, placing carbon source in the mixed solution of deionized water and dimethylformamide, ultrasonically processing for 2-4 hours, and stirring for 3 hours; (ii) slowly dropping aqueous ammonia into the hydrolysis solution of the silicon source while stirring, and adding the dispersion of the carbon source into the solution before the gel is formed, stirring slowly and adding a small amount of ammonia, stopping stirring after 1 minute, allowing the carbonaceous silica gel to stand for 15 minutes and placing in a 45-50 degrees C water bath for more than 24 hours until the gel is stably formed; (iii) placing the mixed gel in a refrigerator at -40 degrees C for 24 hours and transferring to a freeze dryer to obtain a dry gel, placing the dry gel in an alumina crucible, placing the whole crucible in a vacuum tube high-temperature furnace for reaction, and introducing in protective gas, storing at a certain temperature for 4 hours, cooling and taking out the solid to room temperature naturally; (iv) allowing to stand the solid for 2 hours in a mixed solution of hydrofluoric acid and ionized water, and freeze-drying the solid material removed from the solution.