Enhanced absorption bandwidth in carbon-coated supermalloy FeNiMo nanocapsules for a thin absorb thickness

Electromagnetic-wave absorption properties of FeNiMo/C nanocapsules with FeNiMo nanoparticles as cores and carbon as shells have been studied. The FeNiMo/C nanocapsules, synthesized by arc-discharging Fe11Ni79Mo10 (at.%) alloy in ethanol, exhibited outstanding reflection loss (RL < −20 dB) in the range of 13–17.8 GHz with an absorber thickness of 1.7 mm, and an optimal RL of −64.0 dB was obtained at 13.2 GHz with an absorber thickness of 1.9 mm. The broadest bandwidth (RL <  − 10 dB) from 9 to 18 GHz, covering the whole Ku-band (12.4–18 GHz) and almost the whole X-band (9–12.4 GHz), was achieved for a 2 mm layer. The excellent electromagnetic properties are ascribed to the good match between high permeability from the core of FeNiMo nanoparticles and low permittivity from the special core/shell microstructure in the FeNiMo/C nanocapsules.

Research highlights▶ Synthesis of carbon-coated FeNiMo nanocapsules. ▶ The special core/shell microstructure in the nanocapsules results in the low permittivity. The good match between high permeability and low permittivity result in outstanding EM-wave absorption properties of FeNiMo/C nanocapsules. ▶ The FeNiMo/C nanocapsules, synthesized by arc-discharging Fe11Ni79Mo10 (at.%) alloy in ethanol, exhibited outstanding reflection loss (RL < −20 dB) in the range of 13–17.8 GHz with an absorber thickness of 1.7 mm, and an optimal RL of −64.0 dB was obtained at 13.2 GHz with an absorber thickness of 1.9 mm. The broadest bandwidth (RL < −10 dB) from 9 to 18 GHz, covering the whole Ku-band (12.4–18 GHz) and almost the whole X-band (9–12.4 GHz), was achieved for a 2 mm layer.