High-temperature dielectric and electromagnetic interference shielding properties of SiCf/SiC composites using Ti3SiC2 as inert filler

Ti3SiC2 filler has been introduced into SiCf/SiC composites by precursor infiltration and pyrolysis (PIP) process to optimize the dielectric properties for electromagnetic interference (EMI) shielding applications in the temperatures of 25-600 degrees C at 8.2-12.4 GHz. Results indicate that the flexural strength of SiCf/SiC composites is improved from 217 MPa to 295 MPa after incorporating the filler. Both the complex permittivity and tan delta of the composites show obvious temperature-dependent behavior and increase with the increasing temperatures. The absorption, reflection and total shielding effectiveness of the composites with Ti3SiC2 filler are enhanced from 13 dB, 7 dB and 20 dB to 24 dB, 21 dB and 45 dB respectively with the temperatures increase from 25 degrees C to 600 degrees C. The mechanisms for the corresponding enhancements are also proposed. The superior absorption shielding effectiveness is the dominant EMI shielding mechanism. The optimized EMI shielding properties suggest their potentials for the future shielding applications at temperatures from 25 degrees C to 600 degrees C. (C) 2015 Elsevier Ltd. All rights reserved.