SiC nanofibers modified Si3N4 ceramics for improved electromagnetic interference shielding in X-band

Home-made SiC nanofibers were introduced into Si3N4 matrix for enhanced electromagnetic interference (EMI) shielding properties. The microstructural characterization revealed that SiC nanofibers modified Si3N4 ceramic is composed of SiC conductive networks made of uniformly distributed SiC nanofibers, micro-pores and insulating Si3N4 matrix. Moreover, EMI shielding effectiveness (SET) for SiC nanofibers modified Si3N4 ceramic is dependent on SiC nanofibers content. When the SiC nanofibers content is increased from 0 to 8 wt%, the EMI SET of as prepared ceramics increased from 3.43-4.15 dB to 5.58-9.31 dB. Due to the low electrical conductivity of as prepared ceramics, multi-reflection caused by the micro-pores and nanofibers networks is mainly responsible for the EMI shielding. The study indicates that introduction of SiC nanofibers would be a favorable solution for Si3N4 based thermostructural material with an improved EMI shieding.