Large-scale preparation of Co nanoparticles as an additive in carbon fiber for microwave absorption enhancement in C band

Abstract

Recent studies have found that the core–shell structured metal nanoparticles and porous carbon nanofibers (PCNF) are combined into a microwave absorbing material through electrospinning, which exhibits excellent microwave absorption performance. In this study, the core–shell structure Co nanoparticles prepared by the self-developed HEIBE process (production rate of > 50 g/h) were combined with porous carbon fibers, and their absorbing properties were greatly improved. The morphology of Co/PCNF demonstrated that CoNPs are randomly dispersed in the porous carbon nanofibers and carbon nanofiber form complex conductive network which enhances the dielectric loss of the materials. Meanwhile, the Co/PCNF has a low graphitization and shows a significant improvement in permittivity due to the combination of CoNPs and high conductivity of carbon material. The maximum reflection loss (RL) of Co/PCNF reaches − 63.69 dB at 5.28 GHz with a thickness of 5.21 mm and the absorption bandwidth (RL ≤ − 10.0 dB) is 12.92 GHz. In terms of 5.60 mm and 6.61 mm absorber, there are two absorption peaks of − 47.64 dB and − 48.30 dB appear around 12.50 GHz and 14.10 GHz, respectively. The results presented in this paper may pave a way for promising applications of lightweight and high-efficiency microwave absorbing materials (MAMs).

Fabrication of clay soil/CuFe2O4 nanocomposite toward improving energy and shielding efficiency of buildings

“…Accordingly, the permeability, permittivity, and impedance matching (Z) are the vital parameters paving the way for the microwave absorption. Besides, the simulation of the matching thickness was evaluated using quarter wavelength mechanism, declaring that the incident waves can be canceled by reversal waves from the reflector (180° out of phase) in which the thickness of absorber is odd numeral of λ/4 of penetrated wave 39 – 41 . The electrical conductivity and polarization play the crucial roles tailoring permittivity while natural and exchange resonance as well as eddy current effect tune permeability.…”

Hardness and Wettability Characteristics of Electrolytically Produced Copper Composite Coatings Reinforced with Layered Double Oxide (Fe/Al LDO) Nanoparticles

“…However, the proportion of carbon and oxygen in this coating is higher compared to a pure copper coating. This indicates an increased absorption power of the composite coating and a slightly more porous structure, so that the retention of oxygen and carbon is increased [41]. The cross-sections of Cu-Fe/Al LDO coatings and the elemental mapping image analysis of all thicknesses were also performed (Figure 8).…”

Recent Progress of One-Dimensional Nanomaterials for Microwave Absorption: A Review

“…(g) Illustration for main microwave attenuation mechanisms. Reprinted with permission from ref . Copyright 2021 Springer.…”

“…Recently, metal nanoparticles and porous carbon nanofibers (PCNFs) are usually combined with each other to form core−shell structure composite absorbers, which presents an excellent EMWA performance. Zhu et al 110 prepared a Co nanoparticle-decorated 1D porous carbon fiber (Co/PCNF) core−shell structure composite. The core layer of porous carbon nanofibers formed a complex conductive network, and the shell layer of magnetic Co nanoparticles was randomly covered on the porous carbon nanofibers (Figure 6b−f).…”