Synthesis and microwave absorption characterization of SiO₂ coated Fe₃O₄–MWCNT composites

Abstract

This study investigated the microwave absorption properties of core-shell composites containing; iron oxide decorated carbon nanotubes (CNTs) and silica (SiO2@Fe3O4-MWCNTs) with various thicknesses of silica shells (7, 20 and 50 nm). Transmission electron microscopy (TEM) and X-ray diffraction results confirmed the formation of these core-shell structures. Microwave absorption characterization of the samples at the ranging band under consideration (the X-band) showed increased absorption and shifting of the peaks to lower frequencies compared to the uncoated sample (Fe3O4-MWCNTs). The minimum reflection loss decreased with increasing SiO2 thickness. The minimum reflection loss of the composite with an optimized thickness of the silica shell (7 nm) exceeded -41 dB at 8.7-9 GHz.

Facile synthesis and enhanced microwave absorption properties of novel hierarchical heterostructures based on a Ni microsphere–CuO nano-rice core–shell composite

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Investigation of the electromagnetic absorption properties of Ni@TiO2 and Ni@SiO2 composite microspheres with core–shell structure

“…[1][2][3] These electromagnetic waves can harm the human body and can also affect the life and performance of electrical circuits. 4,5 Consequently, there is a high demand for absorbing materials, which can absorb microwaves effectively and convert EM energy into thermal energy.…”

Solvothermal synthesis and good microwave absorbing properties for magnetic porous-Fe3O4/graphene nanocomposites

“…3(c), the excellent wave absorbing properties including the optimal minimum RL value of -43.7 dB at 6.8 GHz with a sample thickness of 5 mm can be obtained in Fe 3 O 4 /GO composites with 7 wt% GO additions, which is superior to those of the most of magnetite-based composites reported in the previous literatures. 24,25 From 3D RL images shown in Fig. 3(d) that for this composite sample, the large minimum RL values and broad absorption bandwidth can be achieved at low frequency range with increasing sample thickness, which can present their practical application scopes so as to guide their actual application as high-performance microwave absorbing materials.…”