Electromagnetic and microwave absorbing properties of carbon-encapsulated cobalt nanoparticles

Electromagnetic and microwave absorption of carbon-encapsulated cobalt nanoparticles, which were synthesized by the CVD method using NaCl as the catalytic support, have been investigated. The real and imaginary parts of permittivity and permeability of carbon-encapsulated cobalt nanoparticle composites rise with the increasing of nanoparticle concentration. The carbon-encapsulated cobalt nanoparticles/paraffin composite achieves a reflection loss below -10 dB in the frequency range of 7.4-11.8 GHz, and the minimum value reaches -18.6 dB at 8.8 GHz. The microwave-absorbing peaks of composites containing carbon-encapsulated cobalt nanoparticles shifts to low frequency region with the increasing of nanoparticle concentration. (C) 2017 Elsevier B.V. All rights reserved.