Preparation And Microwave Absorption Properties Of NiCo Alloy/Carbon-based Composites

Nowadays,electromagnetic microwave has been widely used in communication,medical,military and many other fields.However,the microwave pollution caused by its wide application is becoming more and more serious.Therefore,the preparation of microwave absorption materials which can convert microwave energy into heat energy and other energy is considered to be one of the effective methods to solve this problem.Existing studies have proved that the composite material combining magnetic component and dielectric component has excellent microwave absorption properties.Based on this,in this paper,nickel-cobalt alloy（NiCo）based magnetic components were prepared with different morphologies of nickel-cobalt alloy/carbon matrix composites with different carbon materials,and the microwave absorption performance and its potential microwave absorption mechanism were studied.The main findings are as follows:（1）Spherical NiCo alloys with different micro and nano sizes were prepared by simple hydrothermal method.The influence of the molar ratio of nickel to cobalt on the microwave absorption property of the alloy was investigated.The results show that the microwave absorbing properties of the alloys can be adjusted by changing the molar ratio of nickel and cobalt in the alloy.The minimum reflection loss(RL_min)was-53.29 d B.When the thickness was 2.84 mm,the maximum effective absorption bandwidth（EAB）of Ni₆Co₄alloy was 6.6GHz,covering C,Ku and the entire X band.（2）NiCo-APs@HCC composites were successfully prepared by in situ hydrothermal modification of magnetic NiCo alloy particles（NiCo-APs）on the surface of hydrophilic carbon cloth（HCC）.The results showed that NiCo-APs@HCC composites exhibit a unique corncob-like structure,which was helpful to increase the multiple reflection and scattering of microwaves,thus improving the microwave absorption performance of the composites.When the thickness of NiCo-APs@HCC composites was 2.29 mm,its RL_min was-41.80 d B.EAB was5.8 GHz,almost spanning the entire Ku band.（3）NiCo alloy bimetallic nanosheets arrays with core-shell heterogeneous structure and hydrophilic carbon cloth（NiCo-BNSAs@HCC）composites were prepared by solvothermal method combined with heat treatment.The results showed that NiCo-BNSAs were uniformly coated on the surface of the hydrophilic carbon fiber to form a heterogeneous core-shell structure.This special structure can not only improve the multiple reflection and scattering of microwave,but also improve the impedance matching of the materials and increase the interface polarization loss,so as to improve the microwave absorption performance of the materials.When the matching thickness of NiCo-BNSAs@HCC composite was 1.35mm,the RL_min was-75.4 d B,and when the matching thickness was 1.10 mm,the EAB was 3.6 GHz.The composites have good microwave absorption performance under extremely thin thickness.（4）NiCo-BNSAs/RGO/MDCF composites were prepared by solvothermal method combined with heat treatment.The results showed that the flake RGO interspersed in the carbon foam skeleton not only supports the carbon skeleton,but also increases the specific surface area of the material.The RL_min of NiCo-BNSAs/RGO/MDCF composite was-67.8 d B,EAB was2.9 GHz,and by adjusting the matching thickness,the EAB can cover the whole C and X bands.Figure[56]Table[8]Reference[123]...