▎ 摘　　要

NOVELTY - Composite material comprises 35-70 wt.% polytetrafluoroethylene (PTFE), 24-59 wt.% modified ceramic powder, and 1-6 wt.% fluorinated graphene, where the ceramic powder is treated with a high-temperature coupling agent, and the coupling agent accounts for 0.5-2.5 wt.% of the silicon dioxide. USE - Composite material. ADVANTAGE - The composite material has increased density, reduced porosity, improved dielectric properties, mechanical properties, and thermal stability, has excellent comprehensive performance, simple processing technology and good application prospect. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the composite material, which involves: (A) mixing ceramic powder with ethanol, stirring at room temperature for 0.5-1 hours, adding 0.5-2.5 wt.% high temperature resistant coupling agent of ceramic powder, adding deionized water at the same time, using acetic acid to adjust the pH to 3-5, heating to 65 degrees C, mixing for 1-3 hours, performing suction filtration, washing, drying the product at 110 degrees C for 3 hours at room temperature, crushing and sieving; (B) dispersing graphene oxide uniformly in deionized water, shaking ultrasonically for 1 hour, filtering to remove insolubles to obtain a uniform dispersion of graphene oxide, adding the dispersion to a reaction vessel containing a PTFE lined with a certain amount of hydrofluoric acid and stirred gently, heating the reaction vessel at a certain temperature for a certain period of time, cooling down to room temperature, washing multiple times with deionized water to a pH of 7, filtering and drying to obtain fluorinated graphene powder; (C) mixing the modified ceramic powder and fluorinated graphene powder with PTFE powder according to a certain ratio and drying, adding a certain amount of lubricant, soaking, extruding into a certain shape of the embryo body through an extruder, rolling the embryo body repeatedly by two rollers, where the final PTFE composite material is made into a sheet shape, and placing the PTFE sheet in an oven at 230-250 degrees C for 24 hours; (D) superimposing the multiple dried sheets on each other placing under a cold press at 45-60 megapascal for 0.5-1.0 hour, placing in a precise temperature control sintering furnace, performing sintering using temperature raising process, where the temperature is raised from room temperature to 160 degrees C at 1.5 degrees C per minute, kept warm for 1 hour, the temperature is increased from 160-260 degrees C at 1 degrees C per minute, incubated for 1 hour, and the temperature is finally raised to 360-380 degrees C at a rate of 0.5 degrees C per minute, incubated for 2 hours; and (E) cooling by reducing the temperature from 360-380 degrees C to 260 degrees C at 0.5 degrees C per minute, incubating for 1 hour, reducing the temperature from 260 degrees C to 160 degrees C at 1.5 degrees C per minute, incubating for 0.5 hour, and finally reducing the temperature to room temperature at a cooling rate of at 2 degrees C per minute.