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.