Preparation Of Dielectric/Magnetic Metal Nanoparticles Composites And Study On Their Microwave Absorption Performance

The vigorous development of microelectronic instruments and 5G era has brought convenience and progress to human life,but the accompanying excessive electromagnetic wave pollution will harm human health,communication system and even national security.In order to solve the above problems and adapt to the complex application environment,it is urgent to have light weight,strong absorption capacity and wide effective absorption band of electromagnetic wave absorption materials.The microstructure,dielectric loss capacity and magnetic loss capacity of materials are the main factors that affect the corresponding properties of materials to electromagnetic wave.Therefore,controlling the structure,dielectric loss and magnetic loss of materials is an effective way to optimize the absorption performance of materials.To this end,this study combined dielectric materials and magnetic nanoparticles to prepare hybrid composite materials and core-shell composite materials,and studied their electromagnetic wave absorption properties.Specific research contents are as follows:(1)Firstly,two-dimensional MXene material was selected as the source of dielectric loss.Through simple electrostatic adsorption principle,NiCo2S4 nanoparticles,as the source of magnetic loss,were loaded between layers.The prepared MXene-NiCo2S4 composite has abundant surface defects,unsaturated bonds and suspended bonds,and the synergistic effect of dielectric and magnetic losses,which can guarantee the performance of high reflection losses.The results show that the minimum reflection loss of MXene-NiCo2S4 laminated composite reaches-62.62 dB and the effective absorption bandwidth is 3.24 GHz when the filling amount is 20 wt%.(2)To enrich the heterogeneous interface of materials,increase the microwave transmission path.Biomass carbon microspheres were used as the dielectric material of coreshell materials,and nano-grass like CoNiO2 magnetic shells were grown on the surface.It’s grass-like structure with large surface area,unique core-shell structure,magnetic loss and dielectric loss properties endow C@CoNiO2 microsphere composite excellent microwave absorption performance,excellent impedance matching performance,excellent attenuation performance and synergistic double loss mechanism.In the case of low filling load,the lowest reflection loss reaches-44.06 dB and the effective absorption bandwidth reaches 7.04 GHz.Due to its biomass-derived carbon composites and excellent electromagnetic wave absorption properties,it has shown great potential for practical wave-absorbing applications in microwave technology and aerospace.