Microwave absorption properties of in situ grown CNTs/SiC composites

Abstract CNTs/SiC composites were synthesized by pyrolysis of methane over SiC supported nickel catalysts. The composites show good microwave absorption ability in the frequency range of 2–18 GHz. The pyrolysis temperature has profound influences on the microwave absorption characteristic, and 700 °C is the most suitable temperature for preparation of the composites. The microwave absorption characteristic is also influenced by the Ni loading. By varying the Ni loading from 5 wt.% to 7.5 wt.%, the bandwidth of reflection loss below −10 dB can be broadened by 1.5 GHz under the same conditions. For the composite obtained from 7.5 wt.% Ni loading and the pyrolysis temperature of 700 °C, a minimum reflection loss of −37.6 dB can be obtained at 14.5 GHz with a thickness of 1.9 mm and the bandwidth of reflection loss below −10 dB can reach 5.1 GHz (from 12.4 to 17.5 GHz) with a thickness of 2 mm.