Microwave absorbing hybrid composites containing Ni-Fe coated carbon nanofibers prepared by electroless plating

Microwave absorbing hybrid composites containing metal coated one-dimensional carbon nanomaterials were investigated for wider absorption bandwidth (BW) with thinner thickness. The optimally designed dielectric carbon nanofibers (CNFs)/epoxy composites had 10 dB absorbing BW of 2.8 GHz (8.8-11.6) in the X-band with the content of 3.0 wt.% (2.30 mm thickness). For the improvement of the magnetic characteristics of the fillers, Ni-Fe coated CNFs were prepared by electroless plating. The typical thickness of Ni-Fe deposited layers was about 200-300 nm. Using the prepared hybrid nanofillers, optimally designed Ni-Fe coated CNFs/epoxy composites had 10 dB absorbing BW of 3.7 GHz (8.3-12.0) in the X-band with the content of 40.0 wt.% (2.40 mm thickness). The 10 dB absorbing BW per unit thickness is about 1.54 GHz/mm. The hybrid composites showed about 26% improvement over the dielectric composites. (C) 2011 Elsevier Ltd. All rights reserved.