▎ 摘　　要

NOVELTY - Preparing graphene network toughened zirconium carbide-silicon carbide (ZrC-SiC) ultrahigh temperature ceramic material involves adding graphene oxide powder to deionized water, then stirring for 20-30 minutes, and subjecting to ultrasonic treatment for 10-15 minutes to obtain aqueous graphene oxide solution. The polyvinyl alcohol is added to the aqueous graphene oxide solution and mixed under continues stirring for 20-30 minutes to obtain graphene oxide dispersion. The graphene oxide dispersion obtained is added into directional freezing device, then pre-frozen for 6-10 hours at a temperature of -20 degrees C to -10 degrees C, and then vacuum freeze-dried to obtain Poly(vinyl alcohol) (PVA) modified graphene network. The PVA modified graphene network obtained is thermally reduced for 5-10 hours at a temperature of 70-100 degrees C, then placed in a vacuum impregnation apparatus, impregnated with a ceramic slurry, and then vacuum dried to obtain graphene green body wrapped with ceramic powder. USE - Method for preparing graphene network toughened zirconium carbide-silicon carbide (ZrC-SiC) ultrahigh temperature ceramic material. ADVANTAGE - The method enables to prepare graphene network toughened zirconium carbide-silicon carbide (ZrC-SiC) ultrahigh temperature ceramic material, which has increased fracture toughness from 3.82MPam1/2 is to 4.26MPa m1/2, critical crack size from 26.8 mu m to 119.4 mu m, breaking power from 44.7J/m2 to 151.6J/m2. DETAILED DESCRIPTION - The green body of the graphene network-wrapped ceramic powder obtained is sintered by a discharge plasma at a temperature of 1750-1850 degrees C for 10-15 minutes to obtain desired graphene network toughened ZrC-SiC ultra-high temperature ceramic material.