Preparation and microwave absorption properties of carbon nanocoils

Carbon nanocoils were prepared by chemical vapour deposition, using commercial acetylene as carbon source, a nickel plate as a catalyst and a phosphorous compound as additive. The carbon nanocoils with diameters in the range of 80-100 nm and lengths of 5-50 mu m are visible from FESEM images. Microwave absorption, complex permittivity and permeability of carbon nanocoils have been investigated at 2-18 GHz. Carbon nanocoils are chiral microwave absorbing materials and exhibit superior microwave absorption compared with the larger carbon microcoils. The reflection loss of the Nomex honeycomb sandwich composites filled with the carbon nanocoils is below - 10 dB (90% absorption) at 8.9-18 GHz in the range of 2-18 GHz, and the minimum value is -32.23 dB at 12 GHz. The bandwidth corresponding to the reflection loss below -10 dB is 8.1 GHz. (C) 2008 Elsevier B.V. All rights reserved.