Preparation Of Ferrite-doped Graphene Oxide-coated Fabrics And Investigation Of Their Electromagnetic Properties

With the rapid development of electronic technology in civil and military fields,electromagnetic protection has attracted great attentions.Electromagnetic shielding materials and absorbing materials are the key to solve the problem of electromagnetic protection.However,most of the existing researches on flexible materials are aimed at reflective electromagnetic shielding materials,which can not fundamentally solve the problem of electromagnetic protection because they easily cause secondary pollution when reflecting electromagnetic waves.Absorbing materials can transform electromagnetic waves into heat energy and other forms of energy,so as to attenuate and consume electromagnetic wave energy,which can better solve the problem of electromagnetic protection.The application of absorbing materials is the key factor to solve the problems of electromagnetic radiation pollution,radar stealth and so on.The research of absorbing materials is of great significance to both military and civil fields.In this paper,the flexible graphene oxide(GO)/ferrite composite coated fabric was prepared by combining graphene with magnetic materials with different loss mechanisms and different absorption bands by coating process.It can not only solve the problems of high density and narrow absorption frequency band of magnetic loss-type absorbing materials,but also help to adjust the electromagnetic parameters of the composites to meet the requirements of improving the absorbing performance.In addition,the application of textile fabrics makes the materials have good flexibility.Results show that 30% stainless steel fiber cloth has the best electromagnetic shielding efficiency and dielectric property compared with poly-cotton,arylon cloth and 15% stainless steel fiber cloth in the preparation process of graphene oxide coated fabrics.When the graphene oxide content is 3%,the maximum shielding efficiency of graphene oxide coated fabric can reach 46.27 d B,the maximum real part value of dielectric constant is 25.5,and the maximum imaginary part value is 2.12.It shows that the material has strong polarization and loss ability to electromagnetic wave.When adding magnetic ferrite and graphene oxide doping,the wave-absorbing properties of graphene oxide-ferrite composite coated fabrics are better than those of the pure graphene oxide coated fabrics.Moreover,graphene oxide and ferrite are coated on the surface of conductive fabrics respectively,which is designed to be a layer structure with the interaction of reflection layer,absorbing layer and various loss mechanisms.The composite fabric has the best ability to absorb electromagnetic waves.Among them,when barium ferrite and nickel-zinc ferrite are selected as magnetic wave-absorbing particles,the materials have the best wave-absorbing effect.When the surface graphene oxide content is 3% and the bottom nickel-zinc ferrite content is 30%,the minimum reflection loss of the material at a frequency of 1.32 GHz can reach-11.72 d B.When the surface graphene oxide content is 3% and the bottom barium ferrite content is 30%,the material has a minimum value of ?11.41 d B at 1.32 GHz frequency.The addition of ferrite improves the impedance matching of the material and the two loss mechanisms enhance the absorbing property of the materials.The graphene oxide/ferrite double-layer coating materials also have good static magnetic properties,dielectric properties and mechanical properties.The composite coated fabric designed in this paper can effectively absorb electromagnetic waves in the frequency range of 0.01 GHz-3 GHz,which provides a theoretical basis for the research and development of flexible electromagnetic protection materials.