Microwave absorbing and infrared radiation properties of Al@multi-walled carbon nanotubes composites

In this work, Al@MWCNTs (multi-walled carbon nanotubes) composites were prepared by a one-step hydrothermal method. The effects of the morphology and mass ratio of Al@MWCNTs on microwave absorption were studied. The Al@MWCNTs were also found to participate in infrared emissivity. A large number of MWCNTs were interconnected and interspersed between Al sheets, forming a conductive network. As the mass ratio of MWCNTs in the composite was increased, the microwave absorption performance became stronger, and the infrared emissivity remained excellent. When the mass ratio of MWCNTs:Al was 3:20, the minimum reflection loss of the composite at 10.88 GHz was − 39.24 dB, and the effective absorption bandwidth below − 10 dB were 3.04 GHz (9.2–12.24 GHz), the matching thickness was 2 mm, and the infrared emissivity was only 0.67. In this paper, Al powder, a composite material with low infrared emissivity, was creatively used to achieve the superior material bifunctional absorption of MWCNTs, providing a novel and effective way to design other excellent bifunctional materials in the future.