Preparation And Wave Absorbing Properties Of Nb₂CT_x Composites

Electromagnetic pollution is increasingly serious due to the high frequency use of household appliances and military equipment due to wireless transmission technology.Therefore,the development of electromagnetic wave absorption materials is imminent.In this paper,three composites wave-absorbing systems were prepared by electrostatic self-assembly method to prepare Nb₂CT_x/β-MnO₂,Nb₂CT_x/α-MnO₂and Nb₂CT_x/Fe₃O₄,and systematically studied their composition,micromorphology,magnetic properties and wave absorption capacity,and the following conclusions were drawn:（1）Multi-layer Nb₂CT_xwas prepared by liquid phase etching method,and the absorption performance test was tested with VNA,and the results showed that Nb₂CT_xwas at 13.06 GHz,the minimum reflection loss is-2.34 d B,and the matching thickness is 2.6 mm.Nb₂CT_x/β-MnO₂composites were prepared by electrostatic self-assembly method,and when the mass ratio of Nb₂CT_xtoβ-MnO₂is 1:1,the minimum reflection loss at 16.98 GHz reached-29.22 d B,the matching thickness is4.5 mm,and the bandwidth is 1.36 GHz.In addition,the Nb₂CT_x/β-MnO₂composites has two reflective peaks at a thickness of 4.5 mm,demonstrating dual absorption capacity.The improved EM wave absorbing property originates from the excellent dielectric loss capability of composites（2）Nb₂CT_x/α-MnO₂composites were successfully synthesized by electrostatic self-assembly method,and the influence of MnO₂of different crystal forms on the absorption performance of the composites was studied.Ultra-longα-MnO₂nanowires with an average length of 1.72μm attach to the surface and layer of Nb₂CT_x,resulting in interfacial polarization and dipole polarization,enhancing the dielectric loss capability of the composites and broadening the effective absorption bandwidth.When the Nb₂CT_x/α-MnO₂mass ratio is 1:0.5,the comprehensive wave absorption capacity is the best,with a minimum reflection loss of-27.99 d B at 14.43 GHz,a matching thickness of 1.8 mm,and a bandwidth of 4.88 GHz.（3）Nb₂CT_xMXene was composited with Fe₃O₄prepared at different reaction temperatures by electrostatic self-assembly method to obtain Nb₂CT_x/spherical Fe₃O₄composites,and the wave absorption capacity of the material was optimized through the synergy between the internal dielectric loss and magnetic loss of the material.At the microwave frequency of 14.26 GHz,the minimum reflection loss is-30.14 d B,the matching thickness is 2.2 mm,and the effective absorption bandwidth is 2.39 GHz.The integrated effective absorption bandwidth is 9.12 GHz（6.05 to 15.17 GHz）and the matching thickness range is 2.2 to 4.5 mm,achieving full absorption in the X-band.