High temperature anti-oxidative and tunable wave absorbing SiC/Fe3Si/CNTs composite ceramic derived from a novel polysilyacetylene

With the rapid development of high power electromagnetic (EM) equipment and high-speed aircraft, the powerful and high oxidation-resistance absorbers are fundamentally desirable for the EM field. Herein, a novel high temperature anti-oxidative SiC/Fe3Si/CNTs composite is synthesized by a facile polymer derived ceramic (PDC) route from a Fe-containing polysilyacetylene (PSA). The microstructure of as-prepared SiC/Fe3Si/CNTs composite absorber is featured by micro-sized SiC ceramic grains with spherical Fe3Si nanoparticles and carbon nanotubes (CNTs) attached to. The vector network analyzer tests show a tunable wave-absorbing performance by adjusting the thickness of layer, and the effective bandwidth (the reflection loss < -10 dB) is 3.3-16.8 GHz for the sample S-1400 (heat treatment at 1400 degrees C in nitrogen flow). The minimal RL value is -41.2 dB at 10.5 GHz at a thickness of 2 mm and an effective bandwidth is nearly 4 GHz (12.9-16.9 GHz) at the thickness of only 1.5 mm. Moreover, after the oxidation treatment at 800 degrees C in the air, this absorber maintains the main structure and shows a good high temperature oxidation resistance. This absorber still remains excellent wave absorption property, in view of a minimal RL value of - 40 dB at the thickness of 3 mm and a bandwidth of 4.8 GHz (10.4-15.2 GHz) at the thickness of 2.5 mm. The mechanism of high EM wave absorption performance is studied and attributed to the impendence matching, polarization, and the magnetic properties. Thus, the SiC/Fe3Si/CNTs composite is a promising EM absorber for high-temperature EM wave-absorbing applications.