Nanoarchitectonics of SiC/multilayer graphene composite powders with wave absorbing properties

Abstract

SiC/multilayer graphene composite powders and SiC nanopowders (SiCNPs) were successfully synthesized via a simple catalyst-assisted carbothermal reduction method using silicon dioxide and expanded graphite. The influences of the catalyst content, heat treatment temperature, and graphite/SiO2 molar ratio on the synthesis of powders were studied. The phase composition and their relative content, morphologies, chemical structures, and microstructures were detected using XRD, SEM, AFM, RAMAN, XPS, FTIR, BET, and TEM, respectively. Electromagnetic wave absorption properties of the products were studied at frequencies from 2 to 18 GHz. The results show that the introduction of Fe catalyst has a pronounced catalytic effect on the synthesis of 3 C-SiC powders. The formation temperature of 3 C-SiC is reduced to 1673 K with 0.5 wt% Fe addition as the catalyst. When the expanded graphite is appropriately excessive (the molar ratio of graphite/SiO2 is 3.5), multilayer graphene with a thickness of about 3.5 nm is formed in-situ in the composite powders. The 3 C-SiC/multilayer graphene composite powders exhibit the optimal electromagnetic wave absorption property. When the filling ratio of 3 C-SiC/multilayer graphene composite powders is 30 wt%, the minimum reflection loss reaches − 53.62 dB at a thickness of 2.04 mm and a frequency of 13.95 GHz. Graphene has a unique internal microstructure, high dielectric loss and good conductivity, which improve the impedance matching of the material and then increase the magnetic loss. It is predicted that the SiC/multilayer graphene composite powder has the potential to become an excellent electromagnetic wave absorber.