Method for preparing graphene based composite wave-absorbing composite material

A method for preparing a graphene based composite wave-absorbing material, comprising:

• dissolving a water soluble barium salt and a water soluble iron salt into deionized water to form a barium salt solution and an iron salt solution, respectively;
• mixing the barium salt solution and the iron salt solution according to a molar ratio of Ba:Fe of 1:12 to obtain a precursor solution having a metallic ion concentration in a range of 0.1 to 1.0 mol/L;
• dispersing a graphene material in deionized water to form a graphene dispersion having a concentration of 0.1 to 0.9 mg/mL;
• adding citric acid, nitric acid and the graphene dispersion into the precursor solution in sequence to form a mixture solution;
• stirring the mixture solution at a temperature of 50 to 75° C. to obtain a sol;
• aging the sol for 18 to 42 h;
• coating the sol on a substrate and drying the sol at a temperature of 60 to 100° C. to obtain a coating layer;
• and
• sintering the coating layer by a laser irradiation having a laser power ranging from 90 to 200 W and an irradiation period of 3 s to 20 s to obtain the graphene based composite wave-absorbing material comprising a compound of a formula of BaFe12O19 and graphene.