Two-Dimensional Basalt/Ni Microflakes with Uniform and Compact Nanolayers for Optimized Microwave Absorption Performance

Abstract

It has been accepted that the uniform distribution of magnetic metal particles is beneficial to microwave absorption, while why the homogeneous magnetic particles on the dielectric substrate improve the electromagnetic loss is still unclear. Herein, metal Ni nanoparticles, two-dimensional (2D) basalt/scattered Ni, and basalt/uniform Ni microflakes are obtained through a pretreatment and electroless deposition process. In comparison to Ni nanoparticles and basalt/scattered Ni, the basalt/Ni microflakes with largely uniform and compact Ni nanolayers on basalt, breaking the percolation limit, are favorable for enhanced electromagnetic attenuation. The Ni nanolayers are convenient for construction of a microscale conductive net and migration of an electron. The 2D heterostructures constructed by basalt substrates and decorated Ni layers boost multiple scattering absorption and promote interfacial polarization. Meanwhile, exposed Ni does not inhibit magnetic resonance, enabling strong magnetic coupling. Consequently, the basalt/Ni microflakes with uniform Ni nanolayers demonstrate better microwave absorption with a minimum reflection loss of −30 dB and an effective absorption bandwidth of 3 GHz at 1 mm. This work shows that the uniform and compact magnetic metal nanolayers are effective in improving the dielectric loss and magnetic loss simultaneously to achieve the high-performance microwave absorption.

Combinatorial Structural Engineering of Multichannel Hierarchical Hollow Microspheres Assembled from Centripetal Fe/C Nanosheets to Achieve Effective Integration of Sound Absorption and Microwave Absorption

“…After the microwave enters the composites, the attenuation constant (α) of the material plays a key role for microwave absorbing ability. The frequency dependences α values can be calculated using the following equation: α = 2 π f c ( μ ″ ε ″ − μ ′ ε ′ ) + false( μ ″ ε ″ − μ ′ ε ′ false) 2 + false( μ ′ ε ″ + μ ″ ε ′ false) 2 It is shown in Figure d that the order of the attenuation ability is Fe/C–500 > Fe/C–600 > Fe/C–700. The strong attenuation ability of Fe/C–500 makes the rapid consumption of microwave energy.…”

Highly anisotropic Fe3C microflakes constructed by solid-state phase transformation for efficient microwave absorption

“…Electromagnetic (EM) interference has emerged as a crucial problem with the rapid development of high-frequency communication techniques and micro-miniaturization of electronic information devices, which has aroused the rapid development of EM wave absorption materials 1 – 6 . Among all these achievements, soft magnetic materials occupy an important position in designing materials because of their excellent magnetic loss abilities induced by high saturation magnetization ( M s ) 5 , 7 , 8 . However, their ferromagnetic resonance behaviors could be impeded by the contradictory relationship between loss ability and frequency, known as the Snoek limit (( μ i − 1) f r = 4 γM s /3) 9 .…”

Ultra-thin Ni@nitrogen-doped polyaniline-derived carbon composites with broadband electromagnetic wave absorption

“…Common electromagnetic wave absorbing materials are mainly divided into dielectric loss and magnetic loss, depending on the mechanisms. For instance, Ti 3 C 2 T x , 8 carbon nanotubes, 9 and derived carbon 10,11 belong to the category of dielectric loss, while metals, 12 alloys, 13 and ferrites 14 are magnetic absorbing materials. The combination of these two types of materials is a classic design idea to achieve high absorption performance, such as biomass-derived tubular carbon fiber/Ni, 15 M(Co, Ni)@polyaniline, 16 and Co 3 O 4 @rGO/celery stalks derived carbon.…”