Enhanced electromagnetic wave absorption properties of NiCo2 nanoparticles interspersed with carbon nanotubes

The NiCo₂ nanoparticles and NiCo₂/carbon nanotubes (CNTs) nanohybrids were prepared by a single-model microwave heating and annealing treatment. It was found that the NiCo₂ nanoparticles were evenly distributed around with CNTs. As a result, the complex permittivity of NiCo₂/CNTs nanohybrids could be adjusted effectively, and achieved a well impedance matching for the microwave absorption. The dielectric loss, magnetic loss mechanism and the impedance matching were also investigated systematically. As a result, the reflection loss (RL) less than −20 dB (99% absorption) were observed at 3.7–16.5 GHz with the thickness of 1.2–4.0 mm; moreover, the maximum bandwidth of the RL values less than −10 dB (90% absorption) was 4.4 GHz (12.5–16.9 GHz), and a minimum RL value of −25.5 dB could be observed at 14.7 GHz with the thickness of 1.3 mm. These performances revealed that the NiCo₂/10%CNTs nanohybrids have a great potential to be used as the lightweight microwave absorption material.