The Study Of Preparation CoFe₂O₄/Ti₃C₂T_x Mxene Composite And Its Wave Absorption Properties

The rapid development and wide use of electronic equipment and wireless communication technology have produced a large number of electromagnetic waves,which not only affect the operation of equipment,but also cause harm to human health.Therefore,light weight and high performance microwave absorbing materials are essential to control electromagnetic pollution and protect human health.As a typical new two-dimensional material,Ti3C2Tx MXene is a potential microwave absorption material due to its unique layered structure,large specific surface area,abundant natural defects and surface functional groups.However,its single dielectric loss mechanism and narrow absorption bandwidth limit its practical application.In order to solve the above problems,CoFe2O4 with high saturation magnetization and high electromagnetic performance was introduced in this project to synthesize CoFe2O4/Ti3C2Tx composite material,CoFe2O4 nanoparticles were uniformly coated on the surface of two-dimensional layered Ti3C2Tx and inserted between layers of Ti3C2Tx.The excellent mechanical properties,excellent electrical conductivity,excellent chemical stability and thermal stability of Ti3C2Tx are combined with the superior magnetic properties of nano-CoFe2O4,so as to achieve the purpose of improving impedance matching and enhancing the performance of absorbing wave.The main work and research conclusions of this paper are as follows:(1)Two-dimensional layered Ti3C2Tx Mxene was successfully prepared by chemical etching.It was found that urea had the best effect on the layer expansion of Ti3C2Tx by using different intercalating agents,and the grain size of Ti3C2Tx was greatly improved.After annealing at 800,950 and 1100?,Ti3C2Tx maintains its original two-dimensional accordion shape.When annealing temperature is 800?,TiO2 and amorphous carbon are formed in the product Ti3C2-800.(2)The magnetic CoFe2O4 nanomaterials with rod-like morphology and spherical morphology were prepared by different methods.The preparation parameters of rod-like CoFe2O4 were determined as follows:the ratio of ethylene glycol to water was 3:1,the solvothermal reaction temperature was 120?,the solvothermal reaction time was 24 h,and the annealing temperature was 750?.Under the reaction parameters,rod-like CoFe2O4 with uniform morphology and size,regular edges and corners,and large aspect ratio was prepared.Pure spherical CoFe2O4 was obtained by sol-gel method at annealing temperatures of 300?;Pure spherical CoFe2O4 was prepared by solvothermal reaction for 16 h with chlorine as raw material.The average particle size of CoFe2O4 is about 155 nm and the dispersion is good.(3)When the thickness of single-phase spherical CoFe2O4 is 1.9 mm,the EABmax(maximum effective absorption bandwidth)of 7.0 GHz appears in the range of 10.7-17.7 GHz.When the thickness of the sample was 2.3 mm,the RLmin at 10.7 GHz was-59.3 dB.The spherical CoFe2O4/Ti3C2Tx composite materials with different CoFe2O4 content were prepared by solvothermal method,which was firmly attached and uniformly coated on the Ti3C2Tx surface or inserted into the interlayer of Ti3C2Tx.When the CoFe2O4 content was 70%,the composite material has effective absorption when the thickness is 1.0 mm.When the content of CoFe2O4 is 80%,the RLmin and EAB of the composites are-77.2 dB and 3.3 GHz,and the corresponding sample thickness is only 2.6 mm.When CoFe2O4 content is 90%,EABmax is 6.5 GHz.