Preparation And Microwave Absorbing Properties Of Micro Flake Fe Based Materials

In recent years,with the rapid rapid development of electronic devices,the modern electronic devices working frequency of GHz are widely used in the field of civilian industry and military.In our living space,there are a lot of electromagnetic waves due to these devices widely use,which not only interfere with each other,but also cause harm to the human body,resulting in electromagnetic pollution in space.Therefore,the magnetic microwave absorption material is an effective method to solve the electromagnetic interference.Among all kinds of absorbing materials,Fe based absorbing materials and their alloys are of great interest due to their high saturation magnetization,permeability and Curie temperature.The magnetic field orientation method reduces the dielectric constant of PACI particles.Oriented for 60 min under magnetic field of 1 kOe,the initial permeability of PACI particles in 1 GHz increases to 5.7,which is 1.43 times that of the initial magnetic permeability of the unoriented samples.When the best matching thickness is 3.20 mm,the effective absorption frequency bandwidth is 1.35 GHz from 1.54-2.93 GHz while the effective absorption bandwidth of the unoriented samples is 0.34 GHz.The strongest absorption intensity is-53.10 dB.The introduction of element Co on the basis of Fe can improve the saturation magnetization,permeability of the alloy and the impedance matching.The heat treatment temperature is 750?,the holding time is 2 h and the heating rate is 5/min.Under this heat treatment condition,the FeCo alloy treated shows better magnetic performance and electromagnetic wave absorption properties,the saturation magnetization Ms is 189.33emu/g,and the coercive force Hc is 71.32 Oe.When the thicness of coating is 2mm,the central frequency is 7.60 GHz,the effective absorption bandwidth is3.73 GHz from 6.00 to 9.73 GHz,the strongest absorption intensity is-52.24 dB,and the percentage absorption bandwidth is 49.08%.In order to enhance the loss capacity of FeCo alloy,we explored the introduction of Ni into FeCo alloy,and explored the effects of different Ni contents on the magnetic properties and microwave absorbing properties of FeCoNi alloy.The experiment shows that the introduction of Ni elements will increase the complex permeability and permittivity of the alloy.When the theory of atomic fraction of Ni elements is 5.26%?measured as 4.14%?,?FeCo?₉₀Ni₁₀ exhibits excellent soft magnetic properties with Mr of 179.33 emu/g and Hc of 102.02 Oe.The alloy has a maximum?''_maxof 2.92and the initial permeability of 1.15 at 1 GHz.Its effective absorption bandwidth is 4.8 GHz from 6.29to 11.09 GHz.The percentage of absorption bandwidth is 58.89%.When the atomic ratio of Ni exceeds the measured 4.14%,the complex permittivity of the FeCoNi alloy increases continuously,which is not conducive to the impedance matching,and the absorption property of the electromagnetic wave is deteriorated.