Carbon coated Co–SiC nanocomposite with high-performance microwave absorption

A carbon coated Co–SiC nanocomposite was fabricated via in situ pyrolysis of methane on a hierarchical Co3O4–SiC nanostructure, which was obtained by hydrothermal synthesis. By the reduction of methane, the Co3O4 was in situ converted to cobalt nanoparticles, and coated by carbon or filled in the CNTs. The as-prepared composite exhibits excellent microwave absorption performance in the frequency range of 2–18 GHz. When the match thickness is 1.8 mm, the composite has a reflection loss value below −10 dB in the range 12.2 to 18 GHz, which nearly covers the whole Ku-band (12–18 GHz). When the thickness is 2.6 mm, the reflection loss value below −10 dB distributes at 8.2–11.5 GHz, covering most of the X-band (8–12 GHz). Moreover, by further tuning the match thickness, the composite can selectively absorb some certain frequency bands of microwaves.