scholarly journals Facile Synthesis of GNPs@NixSy@MoS2 Composites with Hierarchical Structures for Microwave Absorption

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1403 ◽  
Author(s):  
Wenfeng Zhu ◽  
Li Zhang ◽  
Weidong Zhang ◽  
Fan Zhang ◽  
Zhao Li ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Skin Effect ◽  
Hydrothermal Reaction ◽  
Synergistic Effects ◽  
Hierarchical Structures ◽  
Dielectric Losses ◽  
Facile Synthesis ◽  
Molar Ratios

Graphene-based powder absorbers have been used to attain excellent microwave absorption. However, it is not clear if inferior microwave absorption by pure graphene materials can be attributed to impedance mismatching or inadequate attenuation capability. In this comparative study, we focus on these aspects. Graphene nanoplatelets (GNPs) multi-component composites (GNPs@NixSy@MoS2) were prepared by hydrothermal reaction with different S and Mo molar ratios. The morphologies, phase crystals, elemental composition, and magnetic properties of the composites were also analyzed. In addition, microwave absorption of the as-prepared samples was investigated and it revealed that the impedance mismatching could be responsible for inferior microwave absorption; higher conductivity can lead to skin effect that inhibits the further incidence of microwaves into the absorbers. Furthermore, the optimum reflection loss (RL) of GNPs@NixSy@MoS2-2 can reach −43.3 dB at a thickness of 2.2 mm and the corresponding bandwidth with effective attenuation (RL < −10 dB) of up to 3.6 GHz (from 7.0 to 10.6 GHz). Compared with the GNPs, the enhanced microwave absorption can be assigned to the synergistic effects of conductive and dielectric losses.

scholarly journals Enhanced Microwave Absorption and Electromagnetic Properties of Si-Modified rGO@Fe3O4/PVDF-co-HFP Composites

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 933 ◽  
Author(s):  
Yuexuan Li ◽  
Yugang Duan ◽  
Chengmeng Wang
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
High Efficiency ◽  
Vinylidene Fluoride ◽  
Synergistic Effects ◽  
Electromagnetic Properties ◽  
Absorption Mechanism ◽  
Simple Method ◽  
Absorption Frequency ◽  
Enhanced Absorption

Graphene has been regarded as one of the most promising two-dimensional nanomaterials. Even so, graphene was still faced with several key issues such as impedance mismatching and narrow bandwidth, which have hindered the practical applications of graphene-based nanocomposites in the field of microwave absorption materials. Herein, a series of Si-modified rGO@Fe3O4 composites were investigated and fabricated by a simple method. On one hand, the degree of defects in graphene carbon could be tuned by different silane coupling reagents, which were beneficial to enhancing the dielectric loss. On the other hand, the spherical Fe3O4 nanoparticles provided the magnetic loss resonance, which contributed to controlling the impedance matching. Subsequently, the electromagnetic absorption (EMA) properties of Si-modified rGO@Fe3O4 composites with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) were investigated in this work. As a result, the Si(2)-rGO@Fe3O4/PVDF-co-HFP composite exhibited the excellent EMA performance in the range of 2–18 GHz. The maximum reflection loss (RLmax) reached −32.1 dB at 3.68 GHz at the thickness of 7 mm and the effective absorption frequency bandwidth for reflection loss (RL) below −10 dB was 4.8 GHz at the thickness of 2 mm. Furthermore, the enhanced absorption mechanism revealed that the high-efficiency absorption performance of Si(2)-rGO@Fe3O4/PVDF-co-HFP composite was attributed to the interference absorption (quarter-wave matching model) and the synergistic effects between Si(2)-rGO@Fe3O4 and PVDF-co-HFP. This work provides a potential strategy for the fabrication of the high-performance EMA materials.

Synthesis of Hollow Rod-like Hierarchical Structures Assembled by CoFe/C Nanosheets for Enhanced Microwave Absorption

2021 ◽  
Author(s):  
Susu Bao ◽  
Zhijia Song ◽  
Runjing Mao ◽  
Yue Li ◽  
Shuhong Zhang ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Synergistic Effects ◽  
Hierarchical Structures ◽  
Interfacial Polarization ◽  
Ferromagnetic Metal ◽  
Hybrid Structures

Composites of ferromagnetic metal and carbon with hierarchical structures are favoured for strengthening microwave absorption capability due to synergistic effects of hybrid structures and enhanced interfacial polarization. However, it remains...

Facile synthesis of porous coin-like iron and its excellent electromagnetic absorption performance

RSC Advances ◽  
2015 ◽  
Vol 5 (33) ◽  
pp. 25936-25941 ◽  
Author(s):  
Hualiang Lv ◽  
Xiaohui Liang ◽  
Yan Cheng ◽  
Guangbin Ji ◽  
Dongming Tang ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Electromagnetic Scattering ◽  
Special Structure ◽  
Facile Synthesis ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Electromagnetic Absorption ◽  
Absorption Performance

The porous coin-like iron exhibits excellent microwave absorption properties with the optimal reflection loss value of −53.2 dB at a thickness of 1.4 mm. This special structure is attributed to electromagnetic scattering behavior which is benefit for microwave absorption.

Synthesis and microwave absorption enhancement of graphene@Fe3O4@SiO2@NiO nanosheet hierarchical structures

Nanoscale ◽  
2014 ◽  
Vol 6 (6) ◽  
pp. 3157-3164 ◽  
Author(s):  
Lei Wang ◽  
Ying Huang ◽  
Xu Sun ◽  
Haijian Huang ◽  
Panbo Liu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Hydrothermal Reaction ◽  
Sol Gel ◽  
Hierarchical Structures ◽  
Absorption Enhancement ◽  
Sol Gel Process ◽  
Nio Nanosheets

Hierarchical structures of graphene@Fe3O4@SiO2@NiO nanosheets were prepared by combining the versatile sol–gel process with a hydrothermal reaction.

Facile synthesis of a CNT@Fe@SiO2 ternary composite with enhanced microwave absorption performance

RSC Advances ◽  
2015 ◽  
Vol 5 (94) ◽  
pp. 76836-76843 ◽  
Author(s):  
Hualiang Lv ◽  
Guangbin Ji ◽  
Haiqian Zhang ◽  
Youwei Du
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Core Structure ◽  
Pyrolysis Process ◽  
Facile Synthesis ◽  
Ternary Composite ◽  
Absorption Performance ◽  
Microwave Absorption Performance

The CNTs@Fe@SiO2 ternary core-structure was prepared by a simple two-step approach consisting a pyrolysis process and then decomposition. At a thin thickness of 1.5 mm, the optimal reflection loss value of the ternary composite is as high as −14.2 dB.

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

2015 ◽  
Vol 17 (8) ◽  
pp. 6044-6052 ◽  
Author(s):  
Biao Zhao ◽  
Gang Shao ◽  
Bingbing Fan ◽  
Wanyu Zhao ◽  
Rui Zhang
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Core Shell ◽  
Facile Synthesis ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Shell Composite

The microwave absorption properties of a core–shell rice-like CuO-coated Ni composite are superior to those of pure Ni microspheres and CuO nanoflakes. The optimal reflection loss is −62.2 dB at 13.8 GHz.

Transformation of Structure, Magnetic Properties and Microwave Absorption Capability in Nd-Doped Strontium Hexaferrite

2020 ◽  
Vol 855 ◽  
pp. 255-260
Author(s):  
Mukhtar Effendi ◽  
Efi Solihah ◽  
Candra Kurniawan ◽  
Wahyu Tri Cahyanto ◽  
Wahyu Widanarto
Keyword(s):  
Magnetic Properties ◽  
Microwave Absorption ◽  
Solid State Reaction Method ◽  
Strontium Hexaferrite ◽  
Basic Material ◽  
X Ray Diffraction ◽  
Cell Parameters ◽  
Tetragonal Crystal ◽  
Capability Analysis ◽  
Natural Iron

The synthesize of Nd3+-strontium hexaferrite magnetic material by the solid-state reaction method has been successfully carried out. This study aims to determine the effect of Nd3+ on the structure, magnetic properties, and microwave absorption capability of the material. Preparation of (1-x)SrO:xNd2O3:6Fe2O3 where x = 0, 10, 20, and 30 mol% using basic material in the form of SrCO3 powder, Nd2O3 powder and Fe3O4 from natural iron sand. The characterization includes the X-Ray Diffraction (XRD) examination to determine the crystal structure, the Scanning Electron Microscope (SEM) for exploring the surface morphology, Vibrating Sample Magnetometer (VSM) for the magnetic properties investigation of material, and Vector Network Analyzer (VNA) for microwave absorption capability analysis. The XRD results show that the addition of Nd3+ doping increases the number of SrNdFeO4 phases. The phase has a tetragonal crystal system that has cell parameters a = b = 3.846 Å, and c = 12.594 Å. The magnetic properties of the material showed that the addition of Nd3+ decreased the saturation and remanence magnetization values, whereas the value of the coercivity field increased. Meanwhile, the best microwave absorption occurs in samples with the addition of Nd3+ as much as 0.3 mol, which results in a reflection loss value of -18.9 dB with a frequency bandwidth of 3.9 GHz.

Facile synthesis of FeCo alloys with excellent microwave absorption in the whole Ku-band: Effect of Fe/Co atomic ratio

2017 ◽  
Vol 704 ◽  
pp. 289-295 ◽  
Author(s):  
Yan Cheng ◽  
Guangbin Ji ◽  
Zhaoyong Li ◽  
Hualiang Lv ◽  
Wei Liu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Atomic Ratio ◽  
Facile Synthesis ◽  
Feco Alloys ◽  
Ku Band
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