Improving the electrical and microwave absorbing properties of Si3N4 ceramics with carbon nanotube fibers

Carbon nanotube fibers (CNTFs) reinforced Si3N4 ceramics has been prepared by incorporating CNTF preforms into ceramic precursor and followed by the sintering process. A SiC interface layer is formed due to the chemical reaction between Si and CNTs, leading to a good bonding between CNTs and Si3N4 matrix. Due to the ceramic deposition, the oxidation resistance is increased of 200 °C. Furthermore, the CNTs have well orientation and high-volume distribution (7 wt%) in the hybrid composites. Obvious improvements of the electrical conductivity (up to 103 S/m) and the microwave absorbing performance (up to 6 dB at 15 GHz) are obtained for the composites containing CNTFs. Our work provides a meaningful way to fabricate multifunctional ceramics possessing high electrical and microwave absorbind properties.