High-Performance Electromagnetic Wave Absorbing CNT/SiCf Composites: Synthesis, Tuning, and Mechanism.

High-performance electromagnetic (EM) wave absorbing materials are strongly desired in many fields like portable devices and aircraft. Introducing carbon nanotubes (CNTs) to certain materials has been proved to be an effective method leading to good EM wave absorption capability. In this work, CNTs are successfully synthesized on SiC fibers with high speed by using a newly developed method which is far more efficient than the commonly used one. The obtained CNT/SiCf composites exhibit high-performance EM wave absorption capability. With 0.72 wt % CNTs, the reflection loss of the 4 mm composite with only 20 wt % filler loading reaches -62.5 dB with the broad effective absorption bandwidth of 8.8 GHz, covering almost the entire Ku band and three-quarters X band. Moreover, the composites can be added to varying matrices so as to modify their EM wave absorption and other properties. The EM wave absorption performance can be easily tuned in a wide range by varying the CNT content, thickness, and filler loading. This work offers a new route for efficiently synthesizing CNTs but, more importantly, for designing high-performance and multifunctional EM wave absorbing materials.