Synthesis and Microwave Absorbing Properties of Ni/SiO2 Core/Shell Particles

2010 ◽  
Vol 160-162 ◽  
pp. 945-950
Author(s):  
Bo Chong Wang ◽  
Tao Wang ◽  
Liang Qiao ◽  
Fa Shen Li
Keyword(s):  
Impedance Match ◽  
Core Shell ◽  
Frequency Range ◽  
Soft Magnetic ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Properties ◽  
Hydrolysis Method ◽  
Microwave Absorbing ◽  
Shell Particles

In this paper, we report on the microwave absorbing properties of the Ni/SiO2 core/shell soft magnetic material which was synthesized by the tetraethyl orthosilicate (TEOS) hydrolysis method. The SEM patterns were shown that the particles of Ni/SiO2 were more dispersed and homogeneous. Microwave absorbing properties were measured in the range of 0.1–18 GHz. A reflection loss (RL) exceeding −20 dB in the frequency range of 2.6–8.9 GHz was achieved for an absorber thickness of 2.0–5.6 mm, and an optimal RL of −49.5 dB was obtained at 4.4 GHz for the thickness of 3.5 mm. The good microwave absorption properties resulted from a proper impedance match as a consequence of the insulator SiO2 around Ni particles.

Improved dielectric properties and microwave absorbing properties of SiC Nanorods/Ni core-shell structure

2017 ◽  
Vol 10 (06) ◽  
pp. 1750069 ◽  
Author(s):  
Huijing Yang ◽  
Qinglu Wang ◽  
Li Wang ◽  
Zelin Zhang ◽  
Yuanlin Li ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Microwave Absorption ◽  
Shell Structure ◽  
Solution Method ◽  
Core Shell ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Properties ◽  
Core Shell Structure ◽  
Microwave Absorbing

We synthesized SiC nanorods/Ni core-shell structure (SiCR-Ni) by a facile solution method and researched their dielectric and microwave absorption properties. The dielectric and microwave absorbing properties of SiCR-Ni are superior to SiC nanorods (SiC[Formula: see text]. The maximum absorption peak of SiCR-Ni is almost three times that of SiCR. The bandwidth of effective absorption of SiCR-Ni covers 64% of [Formula: see text]-band. The improved properties of SiCR-Ni originate from multi-polarization in the special core-shell structure of SiCR-Ni.

Enhanced Microwave Absorption Properties of FeCo@TiO2 Core-Shell Nanoparticles

2018 ◽  
Vol 15 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Abdolrasoul Gharaati ◽  
Majid Ebrahimzadeh
Keyword(s):  
Tio2 Nanoparticles ◽  
Microwave Absorption ◽  
Core Shell ◽  
Frequency Range ◽  
Absorption Properties ◽  
Shell Nanoparticles ◽  
Microwave Absorption Properties ◽  
Band Frequency ◽  
Microwave Absorbing ◽  
Core Shell Nanoparticles

Background: Microwave absorbing nanocomposite is a kind of material that attenuates the reflection of microwave radiation in the gigahertz frequency range. These materials consist of dielectric and transition nanoparticles tend to exhibit attractive microwave absorption properties due to their high permittivity and permeability loss factors. Method: The FeCo nanoparticles were prepared from the reduction of iron and cobalt ions with hydrazine. Then, the FeCo@TiO2 core-shell nanoparticles synthesized by co-precipitation method and their microwave absorbing performance are investigated. The phase composition, morphology and coercivity properties of the nanoparticles were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The composites of FeCo@TiO2 nanoparticles with the ratio of 30 vol.% and paraffin wax (70 vol.%) in different thicknesses were prepared. The microwave absorption properties of these composites were investigated in the frequency range of 2-18 GHz using the vector network analyzer. Results: These nanocomposites exhibit the excellent microwave absorption characteristics (reflection loss<-20dB) in the bored band frequency range of 6-16 GHz with different absorber thicknesses of 1- 2.2 mm. The maximum absorption capability of -47.76 dB was obtained at the frequency of 7.92 GHz with the thickness of 1.8 mm. Based on this study, it can be argued that the FeCo@TiO2 nanoparticles can be used for the bored band and thin microwave absorbers.

scholarly journals The Preparation of FeCo/ZnO Composites and Enhancement of Microwave Absorbing Property by Two-Step Method

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3259
Author(s):  
Ka Gao ◽  
Junliang Zhao ◽  
Zhongyi Bai ◽  
Wenzheng Song ◽  
Rui Zhang
Keyword(s):  
Single Phase ◽  
Effective Bandwidth ◽  
Frequency Range ◽  
Step Method ◽  
Absorption Properties ◽  
Composite Surface ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing Property ◽  
Microwave Absorbing ◽  
Absorbing Property

In this paper, the flower-like FeCo/ZnO composites were successfully firstly prepared by a two-step method, and their microstructures and microwave absorbing properties were characterized. The results show that with an increase of temperature, the content of ZnO loaded on a FeCo/ZnO composite surface was increased. The optimal reflection loss (RL) value can be reached around −53.81 dB at 9.8 GHz, which is obviously superior to results of previous studies and reports, and its effective bandwidth (RL < −10 dB) is 3.8 GHz in the frequency range of 8.7–11.8 GHz with a matching thickness of 1.9 mm. We considered that a large number of lamellar and rod-like ZnO loaded on nano-FeCo single-phase solid solution by two-step method can significantly improve the electromagnetic wave absorption properties.

Bimetallic MOF-derived porous CoNi/C nanocomposites with ultra-wide band microwave absorption properties

2019 ◽  
Vol 43 (42) ◽  
pp. 16546-16554 ◽  
Author(s):  
Chang Liu ◽  
Jing Qiao ◽  
Xue Zhang ◽  
Dongmei Xu ◽  
Nannan Wu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Fine Particles ◽  
Wide Band ◽  
Ultra Wide Band ◽  
Target Product ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing ◽  
Distributed Elements

The CoNi bimetallic MOF-derived composites were synthesized in this work. The target product is composed of fine particles with uniformly distributed elements of Ni, Co, C. The CoNi/C-650 sample displays good microwave absorbing properties.

scholarly journals Controlling the electric permittivity of honeycomb-like core–shell Ni/CuSiO3 composite nanospheres to enhance microwave absorption properties

RSC Advances ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 1172-1180 ◽  
Author(s):  
Rambabu Kuchi ◽  
Taha Latif ◽  
Sung Woo Lee ◽  
Viet Dongquoc ◽  
Phuoc Cao Van ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Impedance Matching ◽  
Core Shell ◽  
Electric Permittivity ◽  
Next Generation ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Materials ◽  
Absorbing Materials ◽  
Microwave Absorbing

Controlling impedance matching and enhancing absorption properties are crucial for developing next-generation microwave absorbing materials.

Microwave Absorbing Properties of FeXCo1-X(x=0.7, 0.8) Alloys with Spherical Nanoparticles

2011 ◽  
Vol 299-300 ◽  
pp. 484-488
Author(s):  
Fei Wang ◽  
Lian Zhu Zhang
Keyword(s):  
High Resistivity ◽  
Alloy Nanoparticles ◽  
Body Centered Cubic ◽  
Spherical Nanoparticles ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Properties ◽  
Fe Content ◽  
Bcc Structure ◽  
Microwave Absorbing

FexCo1-xalloys were prepared by low temperature hydrothermal method. The influence of Fe content on static magnetic and microwave absorbing properties was studied. XRD results show that FexCo1-xalloys are single-phased body-centered cubic (BCC) structure for both 70% and 80% Fe content. The lattice constant of the alloys increases with increasing Fe content. The coercivity decreases with the increase of Fe content. The composites with high resistivity were prepared by homogeneously mixing FexCo1-xalloy nanoparticles and paraffin wax, and their microwave absorption properties were studied.

Novel Radar Absorbing Materials with Broad Absorbing Band: Carbon Foams

2010 ◽  
Vol 26-28 ◽  
pp. 246-249 ◽  
Author(s):  
Zhi Gang Fang ◽  
Chun Fang
Keyword(s):  
Electric Conductivity ◽  
Carbon Foam ◽  
Impedance Match ◽  
Frequency Range ◽  
Microwave Absorbing Properties ◽  
Replication Method ◽  
Carbon Foams ◽  
Electromagnetic Behavior ◽  
Measured Frequency Range ◽  
Microwave Absorbing

Carbon foams were prepared by a polymer sponge replication method and their microwave absorbing properties were investigated in this paper. It was found that the electric conductivity of carbon foams increases quickly with the improvement of carbonization temperatures. Moreover, the electric conductivity of carbon foams strongly affects their microwave absorbing performances. As the electric conductivity increases from 0.02 S/m to 1.03 S/m, the dominant electromagnetic behavior of carbon foams changes from transmission to reflection with regard to the incident electromagnetic wave. The best microwave absorbing performance was achieved for the carbon foam with an electric conductivity of 0.46S/m when other parameters are fixed at constants, and absorbing values for the carbon foam exceeds 7dB almost in the whole measured frequency range of 4-15GHz, while the frequencies range for absorbing values exceeding 8dB are about 7 GHz, demonstrating a characteristic of broad absorbing bandwidth. It is to be noted that the absorbing characteristic for the carbon foam with an electric conductivity of 0.46S/m is obtained without any impedance match design, which indicates that carbon foams have the possibility to be applied as broad absorbing bandwidth RAMs.

The Influence of Sintering Temperature and Mn-Ti Doped BaFe12O19 on the Microwave Absorbing Properties

2015 ◽  
Vol 754-755 ◽  
pp. 733-737
Author(s):  
M.N. Nasruddin ◽  
Tulus Ikhsan Nasution ◽  
M.S. Achmad ◽  
K. Candra ◽  
F.N. Lukman ◽  
...  
Keyword(s):  
Dopant Concentration ◽  
Sintering Temperature ◽  
Barium Hexaferrite ◽  
Solid State Reaction Method ◽  
Network Analyzer ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Properties ◽  
Magnetizing Force ◽  
Microwave Absorbing

The effect of sintering temperature and Mn-Ti (x = 0.1 and 0.5 % mol) doped in Barium hexaferrite (BaFe12O19) on the microwave absorption properties have been investigated. The BaFe(12-2x)MnxTixO19samples were prepared by using a solid state reaction method from technical grade materials of BaCO3, Fe2O3, MnO2, and TiO2. The permagraph and vector network analyzer (VNA) measurement with frequency of 4 – 10 GHz were used to determine the magnetic properties and microwave absorbing properties, respectively. The magnetic induction and magnetizing force (B-H) curve analysis of BaFe(12-2x)MnxTixO19revealed that by increasing the Mn-Ti dopant concentrations, the remanence (Br) and BH(max) increases, meanwhile, the HCBvalue decreases for both 1100 and 1150oC. The frequency dependence of reflection loss (RL) measurement given anoptimum value of-26.15 dB at frequency of 9.18 GHz which obtained by x = 0.1% mol Mn-Ti (1100oC). The maximum absorption peak was achieved for 0.5 % mol Mn-Ti sample with ~98.3 % at 9.18 GHz. By controlling the sintering temperature and Mn-Ti dopant concentration, the RL and absorption behavior can be modified to desirable values and also indicates that higher Mn-Ti dopant concentration (0.5% mol) possess better absorbing characteristics. Furthermore, it was found that complex permitivitty and permeability values of BaFe12O19can be modified by controlling the Mn-Ti dopant concentration.

Preparation of graphene/Fe3O4/Ni electromagnetic microwave absorbing nano-composite materials

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940055 ◽  
Author(s):  
Yu-Wei Huang ◽  
Yu-Jiang Wang ◽  
Shi-Cheng Wei ◽  
Yi Liang ◽  
Wei Huang ◽  
...  
Keyword(s):  
Composite Materials ◽  
Photoelectron Spectroscopy ◽  
Network Analyzer ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Nano Composite ◽  
X Ray ◽  
Microwave Absorbing Properties ◽  
One Step ◽  
Microwave Absorbing

Graphene/Fe3O4/Ni nano-composite materials were prepared by one-step hydrothermal method from RGO, FeCl3 ⋅ 6H2O and purity Ni. The structure and electromagnetic microwave absorbing properties were investigated systematically by field emission scanning electron microscope (FESEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS) and vector network analyzer (VNA). The reflectance was simulated based on the electromagnetic parameters to evaluate the absorption properties of the sample. The results show that Fe3O4 and Ni are on the surface of graphene evenly, the composites exhibit excellent microwave absorption properties, reflection loss and broad effective absorption bandwidth are −16.38 dB and 3.60 GHz, as the paraffin wax is 40% and the matching thickness is 2.00–3.50 mm.

Sign in / Sign up

Export Citation Format

Share Document