Enhanced Electromagnetic Absorption of Flake Carbonyl Iron/Reduced Graphene Oxide Composites

Carbonyl iron is an excellent microwave absorption material. However, the high density limits its application in lightweight microwave absorbing. In this study, flake carbonyl iron (FCI) was prepared by high-energy ball milling, and mixed with TPU to prepare the TPU/FCI composites. The large shape anisotropy of FCI makes the TPU/FCI samples exhibit higher permittivity and permeability, and consequently better microwave absorption performance than TPU/SCI (spherical carbonyl iron). Then, rGO was added into the TPU/FCI composites. The permittivity of the TPU/FCI/rGO composites is significantly enhanced by a few amount of rGO (less than 0.5 wt.%). As a result, the TPU/FCI/rGO sample with mFCI: mTPU = 3:10 and 0.5 wt.% rGO consumes only half of FCI that the TPU/FCI sample with mFCI: mTPU = 6:10 uses, and shows much better microwave absorbing performance than this TPU/FCI sample, that the minimum reflection loss reaches-68.3 dB (at 3.4 mm) and the effective absorption bandwidth is up to 5.9 GHz (at 1.5 mm). The TPU/FCI/rGO materials demonstrate promising application in light-weight high-efficient microwave attenuation.