Enhanced microwave absorbing performance of CoNi alloy nanoparticles anchored on a spherical carbon monolith

Abstract

CoNi alloy nanoparticles anchored on a spherical carbon monolith (CoNi–C) were prepared by a solvothermal route and subsequent heat treatment without any templates. Their permittivity and permeability behaviors were studied in the frequency range of 2–18 GHz. The CoNi–C composites showed the best microwave absorbing performances compared to those of Co–C and Ni–C. The maximum reflection loss of the CoNi–C nanocomposites can reach −50.2 dB at 7.7 GHz with samples of 4 mm in thickness, better than that of the Ni–C composites, while the Co–C composites showed almost no absorption at all. The absorption mechanism of the three absorbents was also discussed.