Preparation Of Graphene Ferrite Composites And Its Application In Electromagnetic Shielding

In recent years,with the rapid development of radar technologies such as communications,commercial and military applications,many serious problems of electromagnetic pollution have emerged.Therefore,electromagnetic wave absorption and protection technology have gained general attention,and it is one of the effective methods to solve this problem when the absorbing materials with excellent properties are prepared.In this paper,graphene is prepared by chemical method firstly.Then,graphene is combined with the most widely used ferrite,and the absorbing property of the composite is analyzed.The specific work and conclusions are as follows:?1?Graphene,nickel and ferric chloride are selected as raw materials by one step hydrothermal method,and Graphene/NiFe₂O₄ is made by high temperature and high pressure reactor.The analysis shows that the addition of graphene affects the magnetic properties and wave absorbing properties of the composites.With the increase of graphene content,the crystallinity of the Graphene/NiFe₂O₄ increases,and the absorption properties of the composites increases significantly.Under the condition of0.15g of graphene addition,the composites exhibit better microwave absorbing properties.When the addition amount of graphene is 0.15g,the frequency is 14.9GHz.The coating thickness is 2mm.The composite has a maximum absorption intensity of-40.5dB.The effective absorption width is 12.16-17.52GHz.?2?Double phthalic acrylic resin?BPH?and carbonyl iron powder are selected as raw materials by step solvent hot method,and Graphene/Carbony iron powder is made by high temperature calcination.The different solvent thermal time and graphene addition have an effect on microstructure and absorbing properties of Graphene/Carbony iron powder.The analysis of the results shows that,whether it is to increase the solvothermal time or increase the content of graphene,the graphene/carbonyl iron powder composites all undergo interparticle agglomeration and the crystallinity increases.With the increase of graphene content,the microwave absorption properties of Graphene/Carbony iron powder composites have improved significantly.When the solvent heat time is 6h and the addition of graphene is 1%,the composites exhibit better microwave absorbing properties.When the frequency is7.6GHz and the thickness is 2mm,the maximum absorption peak is-53.66dB and the maximum effective absorption frequency is 4GHz.?3?The ball-milled carbonyl iron powder phosphating samples?MZ-II/P?and graphene coated carbonyl iron powder ball mill after phosphating samples?MZ-?/C,P?composite material are made respectively by physical ball grinding.It is investigated that the existence of graphene has an effect on the phosphating treatment,microstructure,wave absorbing properties and corrosion resistance of the composites.The addition of graphene not only increases the microwave absorbing properties of MZ-II/C,P composites,but also improves the corrosion resistance of composites.