Graphene @Fe3O4 compound water base magnetorheological fluid and preparation method thereof

The invention relates to the field of intelligent magnetic materials and in particular relates to a graphene @Fe3O4 compound water base magnetorheological fluid and a preparation method thereof, solving the problems that existing magnetorheological fluids are easy to settle and the stability and magnetorheological effects of the magnetorheological fluids are difficult to optimize at the same time. The preparation method comprises the following steps: preparing a Fe3O4 water base magnetic fluid with FeCl2.4H2O and FeCl3.6H2O; sequentially adding concentrated sulfuric acid, potassium permanganate and hydrogen peroxide to natural flake graphite and sodium nitrate to prepare graphite oxide; and then carrying out ultrasonic dispersion on home-made graphite oxide to prepare graphene oxide, finally adding a surfactant, the Fe3O4 water base magnetic fluid and a reducing agent to graphene oxide, washing the solution with deionized water until the solution is neutral, and then dispersing graphene @Fe3O4 compound magnetic particles in the deionized water to undergo ultrasonic dispersion, removing the precipitates and taking the supernatant, namely the stable graphene @Fe3O4 compound water base magnetorheological fluid, wherein the magnetic particles are graphene @Fe3O4 and account for 5-35wt% of the whole. The method has the advantages of good stability, low zero field viscosity, high shear strain and wide operating temperature range.