A novel synthesize approach and electromagnetic wave absorbing properties of expanded graphite/Fe₃O₄/carbon nanorod composite microstructure

Expanded graphite (EG), as a new carbon nanomaterial, has excellent characteristics, which includes great specific surface area, good electrical conductivity, and excellent mechanical properties. In this study, the microwave puffing method combined a rapid, simple and inexpensive process that has been developed to synthesize EG/Fe₃O₄/carbon nanorod(CN) nanoparticle hybrids, which can be applied as an electromagnetic radiation absorbent. Carbon nanorods not only played a role to connect the graphene layer structure but also promoted a synergistic graphene absorbing effect. Meanwhile, the catalyst of carbon nanotubes was decomposed into nano magnetic particles under microwave conditions, which can improve the absorbing properties of the composite material. The morphologies of the carbon nanocomposites were examined by SEM, EDX and TEM, respectively. The complex relative permittivity and permeability of the absorber were measured using a microwave network analyzer in the frequency range of 2–18 GHz. With an increase of the matching thickness, the maximum absorbing peak of the carbon nanocomposites shifted to a lower frequency region, under above the frequency range. When the matching thickness was 2.4 mm, the minimum absorption peak of the carbon nanocomposites was − 28 dB at 14.4 GHz, and a minimum reflection loss of − 10 dB was achieved within the range of 12.3–17.8 GHz.