The Synthesis Of Tunsten Carbide/Carbon Composites Through Non-solvent Method And Their Microwave Absorption Performance

In recent years,Electromagnetic(EM)pollution has become a global concern owing to its potential threats in physical health,equipment operation,and information security.Microwave absorption emerged as an advanced and sustainable alternative for the precaution of EM pollution,because this promising strategy was established on the fundamental energy conversion through the interaction between EM waves and microwave absorbing materials(MAMs).Among various functional materials with unique EM characteristics,Carbides/carbon composites are emerging as a new kind of binary dielectric systems with good microwave absorption performance.Herein,we obtain a series of tungsten carbide/carbon composites through a simple solvent-free strategy,where the solid mixture of dicyandiamine(DCA)and ammonium metatungstate(AM)is employed as the precursor.During high-temperature pyrolysis,ultrafine cubic WC1-x nanoparticles(3?4 nm)are in situ generated and uniformly dispersed on carbon nanosheets derived from DCA.This configuration overcomes poor chemical homogeneity from large size of conventional carbide particles and is greatly helpful to create abundant heterogeneous interfaces favorable for EM disspation.It is found that the weight ratio of DCA to AM can regulate the chemical composition of these composites effectively,while less impact on the average size of WC1-x nanoparticles.With the increase of carbon content,the relative complex permittivity and dielectric loss ability of these composites are constantly enhanced through conductive loss and polarization relaxation.The difference in dielectric property endows these composites with distinguishable attenuation ability and impedance matching.When the weight ratio of DCA to AM is 6.0,the optimized composite can produce good microwave absorption performance in the frequency range of 2.0-18.0 GHz,which is superior to many conventional carbides/carbon composites.In order to further improve the performance of WCC-6,we obtain a sample of tungsten carbide/carbon composite through a simple solvent-free strategy,where the solid mixture of DCA,AM,and ammonium nitrate(AN),is employed as the precursor.During high-temperature pyrolysis,porous tungsten carbide/carbon composites are in situ generated.This configuration improves the dielectric parameters of the composite material,effectively improves the impedance matching ability of MAMs,and produces good microwave absorption performance in the frequency range of 2.0-18.0 GHz.This work provides a valuable paradigm for ultrafine carbide nanoparticles decorated carbon materials synthesis for further the construction of microstructure.