Electrical and shielding properties of epoxy composites with Ni–C and Co–C core-shell nanoparticles

The electrical and microwave shielding properties of epoxy-based composites (CMs) filled with metal-nanocarbon Ni–C and Co–C core-shell particles have been studied for the broad frequency range (16–67) GHz. The decrease of electrical resistivity of CMs with the increase of Ni content in core-shell particles and temperature in the range of 77–293 K was found. The observed sufficient increase of microwave shielding efficiency (32–40 dB at sample thickness of 2.2 mm) in Ka- and V-band for CMs with high Ni content correlates with increased electrical conductivity. A high microwave absorption index (0.999 at f = 65 GHz) of (Me–C)/epoxy CMs can be attributed to the enhanced dielectric and magnetic losses. The modeling of microwave absorption capability of 60 wt% (Nix-C)/epoxy CMs showed that the microwave absorption peaks can be observed only for the narrow frequency range, (18–25) GHz at a sample thickness of 0.6–1.0 mm with the effective bandwidth (2.3–4.8) GHz. •Epoxy composites filled with 60 wt% of (Ni–C) and (Co–C) core-shell particles.•Decrease of electrical resistivity with increase of Ni content and temperature.•Increase of EMI shielding due to enhanced electric loss for higher Ni content.•Reflection loss in (Ni–C)/epoxy composites versus Ni content and sample thickness.•High microwave absorption index (∼0.999 at f = 65 GHz) for (Ni–C)/epoxy composites.