Microwave Absorption Performance Of Biomass Carbon Materials And Biomass Carbon/Magnetic Nanoparticle Composites

As the microwave absorbing materials,carbon materials have the advantages of light weight and high conductivity.The raw materials of most carbon materials belong to non-renewable resources such as coal and petroleum,and the preparation process is also quite complicated.Biomass carbon materials have the characteristics of renewable,low price,abundant raw materials,simple preparation process and high specific surface area,which have attracted widespread attention of researchers.Magnetic particles can adjust the electromagnetic parameters of biomass carbon materials,achieve better impedance matching,improve microwave absorption performance,and increase effective bandwidth.The specific research contents of this article are as follows:?1?Carbonized photon crystals?CPCs-HTC and CPCs-HC?were obtained by high-temperature carbonization and hydrothermal carbonization of Peacock Feather Fibers and their microwave absorption properties were studied.The SEM shows that the two-dimensional periodic microstructure of photonic crystals is retained in CPCs.Due to high temperature Carbonization,CPCs-HTC has blocking phenomenon,which leads to the increase in the size of rod-like structures.Microwave absorption performance analysis results show that CPCs-HC has poor wave absorption performance,while CPCs-HTC has a minimum reflection absorption of-57.9 dB at a frequency of 7.3 GHz and a thickness of2.5 mm,and the effective absorption bandwidth?RL<-10 dB?of 2.1GHz.?2?Biomass carbon materials?CPMLs?were obtained by high temperature carbonization of peat moss leaves?PMLs?.The microstructure of CPMLs in C/Ni composites is well preserved.Microwave absorption performance analysis shows that the minimum RL value of C-Ni 0.8 mol/L composite material is less than-20 dB in the thickness range of 2.0-3.5 mm.And when the thickness is 2.4 mm,the minimum RL reaches-52 dB,the effective absorption bandwidth?RL<-10 dB?is 2.6 GHz.?3?Peat moss has high water storage characteristics.The peat moss leaves were soaked in KOH solution to prepare activated carbon?AC-1 wt%KOH,AC-3 wt%KOH,AC-5 wt%KOH?.AC-5 wt%KOH with the highest specific surface area and the most abundant pore structure was selected to prepare the AC/Fe₃O₄ composite by hydrothermal method.The porous structure of AC in AC/Fe3O4 composites is well preserved.The minimum RL of AC-Fe3O4 1-1 reaches-51.6 dB at 14.2 GHz with a thickness of 1.6 mm,and the corresponding effective absorption bandwidth is 4.1 GHz.