Design of core-shell nickel oxide/silicon carbide whiskers towards excellent microwave absorption property

Toward the increasingly serious problem of electromagnetic wave pollution, the development of absorbing material with the properties of the light, thin, wide, strong, and multiple applications scenarios is still a huge challenge. Herein, the core-shell nickel oxide/silicon carbide whiskers (NiO/SiCw) with variational NiO morphologies (tulle-, flower, and rod-like) were designed and fabricated via a facile pre-hydrothermal method and post-annealing process. For the NiO shell morphology, it can effectively be controlled by the proportion of Ni(NO3)(2)center dot 6H(2)O, NH4Cl, and CO(NH2)(2). The structure of NiO/SiCw samples was investigated by XRD, SEM, XPS, TEM, and N-2 absorption-desorption. Compared to other morphologies of NiO, the flower-like NiO/SiCw possess a porous structure and large surface area that can benefit from the multiple reflections and attenuation of the microwave. As an absorber, the composite with the flower-like NiO/SiCw filler loading of 50% manifests a superior microwave attenuation capability due to its special porous structure, good impedance matching, and large dielectric loss induced from heterojunction interfacial polarization. The minimum reflection loss of flower-like NiO/SiCw is up to -56.8 dB with a thickness of 1.9 mm, and the maximum effective absorption bandwidth (EAB) reaches 5.17 GHz. The as-prepared flower-like NiO/SiCw with strong absorption, thin thickness, and width EAB can meet the potential requirements for microwave absorption materials under oxidation environments. (C) 2021 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.