Effects of upgrading temperature on electromagnetic shielding properties of three-dimensional graphene/SiBCN/SiC ceramic composites

SiC coating is introduced using MTS-H-2-Ar system via chemical vapor deposition technology. SER and SET of the composites increased from 7.5 dB to 18.9 dB-9.1 dB and 20.8 dB, respectively, due to the deposition of SiC coating. The influence of oxidation temperature on microstructure and electromagnetic interference shielding performance has been systematically investigated. The morphology of GF/SiBCN/SiC composite remained unchanged after oxidation at 900 degrees C. However, condensed particles which distributed around cauliflower-like structure disappeared and were replaced by some small particles with increasing temperature. The GF/SiBCN/SiC ceramic composites exhibited mass loss after oxidation at 900 degrees C initially and saw a slight mass gain afterwards. Graphene layers kept their integral structure and SET retention rate of 97% and 93% have been recorded after oxidation at 900 degrees C and 1100 degrees C for 10 h, respectively.