| The pollution of electromagnetic waves has become one of the main sources of harm to human health and electronic information equipment.For this reason,the research and development of microwave absorbing materials is of great significance.Microwave absorbing materials are divided into three types:magnetic loss,dielectric loss and composite loss.Magnetic nano spinel ferrite has the characteristics of strong magnetic loss,good impedance matching,light weight and simple synthesis process,and has very important applications in the field of microwave absorption.CuFe2O4 and CoFe2O4,as typical spinel ferrites,have good magnetic permeability and dielectric constant,and there are many vacancy defects in the crystal structure,which provide the basis for their doping modification and recombination.As an ultra-light material,graphene oxide has a huge specific surface area and a high carrier migration rate.It is one of the preferred microwave absorbing materials to achieve light weight and strong absorption.A single absorbing material always has disadvantages such as single absorption mechanism,low absorption strength,and poor impedance matching performance.For this reason,composite modification of materials with different excellent performance can effectively solve these problems.This subject mainly studied the microwave absorption properties and microwave absorption mechanism of CuFe2O4,CuFe2O4/RGO and CoxCu1-xFe2O4/RGO,and the shielding effectiveness of the doped electromagnetic shielding coating film material prepared by the composite of Co0.5Cu0.5Fe2O4/RGO and styrene-acrylic emulsion was explored.The specific conclusions are as follows:1.Adjust the crystal structure of CuFe2O4 particles through the time and temperature of the hydrothermal reaction,and realize the adjustment of the magnetic properties of CuFe2O4 particles.The study found that the saturation magnetization of CuFe2O4 particles synthesized under 180℃ and 10h conditions is 30.69emu/g;it has the best reflection loss at a thickness of 4.50mm and a frequency of 6.00GHz,which has the best reflection loss of-25.8dB;The microwave absorption mechanism of CuFe2O4 nanoparticles is mainly to absorb electromagnetic waves in the form of eddy current loss,magnetic resonance and natural resonance.2.CuFe2O4/RGO composite materials was prepared by compounding different ratios of graphene oxide and CuFe2O4 particles,and studied the modification effects of the dielectric properties and microwave absorption properties of the composite materials.The results show that the micro morphology of CuFe2O4/RGO is that CuFe2O4 nanoparticles grow on the surface of the wrinkled graphene oxide sheet;the average particle size of CuFe2O4/RGO-20 is 279.3nm,and it’s best reflection loss reaches-58.70dB,the maximum effective absorption bandwidth is 6.03GHz.The dielectric loss of CuFe2O4/RGO composite is significantly enhanced,and microwaves are dissipated under the combined action of magnetic loss and dielectric loss.3.In order to further increase the effective absorption bandwidth of the material and expand the application range of the material,the crystal structure of CuFe2O4 particles was doped with Co element to prepare CoxCu1-xFe2O4/RGO nanocomposite material,and the microwave absorption of different element ratios was studied.Performance impact.The study found that the average particle size of the Co0.5Cu0.5Fe2O4/RGO nanocomposite is 298.3nm.While maintaining the original three-dimensional network structure,the maximum effective absorption bandwidth is increased to 6.34GHz,and the reflection loss value is kept relatively high(-58.25dB);The magnetic loss ability of the doped CoxCul-xFe204/RGO nanocomposite is significantly enhanced.4.The doped electromagnetic shielding coating film was prepared with styrene-acrylic emulsion as the matrix and Co0.5Cu0.5Fe2O4/RGO as the microwave absorbing filler,and the electromagnetic shielding performance of electromagnetic shielding coating film with diffident addition amount of Co0.5Cu0.5Fe2O4/RGO nanocomposite was studied.Studies have shown that the doped electromagnetic shielding coating film is a non-impedance-matched material,and uses reflection to achieve electromagnetic wave shielding;when the Co0.5Cu0.5Fe2O4/RGO nanocomposite is added at 5.0%,the best shielding effectiveness is 5.48dB of the film.Figure[62]Table[14]References[88]... |
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