Carbon nanowires reinforced porous SiO2/3Al2O3•2SiO2 ceramics with tunable electromagnetic absorption properties

Porous SiO2/3Al(2)O(3)center dot 2SiO(2) ceramics decorated with carbon nanowires (CNWs) were manufactured by catalytic chemical vapor deposition (CCVD) for wide absorption band and high absorption application. The results show that the as-prepared CNWs grow uniformly in porous SiO2/3Al(2)O(3 center dot)2SiO(2) ceramics to form the three dimensional (3D) structure. The content of CNWs can be effectively controlled by changing the weight of catalyst, and the dielectric properties of CNWs-SiO2/3Al(2)O(3)center dot 2SiO(2) composite ceramics can be tuned. As expected, the CNWs-SiO2/3Al(2)O(3)center dot 2SiO(2) composite ceramics possess wonderful electromagnetic (EM) absorption properties due to the effects of conductive loss, impedance match and dipoles polarization. It can be concluded that the minimum reflection coefficient (RCmin) of CNWs-SiO2/3Al(2)O(3 center dot)2SiO(2) composite ceramics reaches -31 dB at 9.1 GHz (which means 99.9% of EM wave powers are absorbed) and the effective absorption bandwidth (EAB) covers the whole X-band (8.2-12.4 GHz) at the thickness of 5.0 mm.