▎ 摘　　要

NOVELTY - Composite material comprises 3D graphene and aluminum dihydrogen phosphate adhesive, where the adhesive is filled in the pores of the 3D graphene and/or coated on the outer surface of the 3D graphene. USE - The composite material is used for stealth structure design on high-end weapons and equipment, an electromagnetic wave absorption device, and in aviation equipment or aerospace equipment (all claimed). ADVANTAGE - The composite material has compressive strength of 28.6 MPa or more at room temperature, even after being kept at 1000 degrees C for 20 minutes, its compressive strength is still more than 22 MPa, has excellent wave absorbing performance in the frequency range of 2-18 GHz, has excellent high temperature resistance, and excellent mechanical properties. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the composite material comprising (a) preparing 3D graphene framework, (b) weighing the components of aluminum dihydrogen phosphate colloid, silicon powder, boron oxide, zinc oxide and aluminum oxide according to the preset ratio, (c) adding the weighed above components in a mixer and mixing evenly, (d) filling the above-mentioned uniformly stirred mixture into the pores of the 3D graphene framework and/or coating on the surface of the three-dimensional graphene framework, placing at room temperature for 2-24 hours, and placing in an oven at 2-5 degrees C/minute, raising temperature to 60-80 degrees C, heat-preserving for 12-24 hours, continuously increasing to 150-200 degrees C, heat-preserving for 1-5 hours and cooling down naturally to obtain a preliminarily solidified composite material sample, and (e) heating the sample obtained in step (d) at 650-1000 degrees C at a heating rate of 5-20 degrees C/minute in an inert atmosphere, and maintaining the temperature for 20-120 minutes to obtain the composite material.