scholarly journals Improving Impedance Matching of Flaky Carbonyl Iron Based on the Surface Modification by Binary Coupling Agents

2021 ◽  
Author(s):  
Huimin Wu ◽  
Guozhi Xie ◽  
Yan Zhu ◽  
Ningyan Xie ◽  
Jing Chen
Keyword(s):  
Surface Modification ◽  
Coupling Agent ◽  
Carbonyl Iron ◽  
Impedance Matching ◽  
Coupling Agents ◽  
Tangent Loss ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Minimum Reflection Loss

Abstract In this paper, the impedance matching of the flaky carbonyl iron was improved by surface modification with binary coupling agents. The microstructure, phase and electromagnetic parameters were detected by scanning electron microscope (SEM), X-ray diffraction (XRD) and Agilent vector network analyzer, respectively. After binary coupling agent applied, the shape and particle size of the flaky CIP have changed significantly, whereas the phase remained α-Fe phase. On the other hand, with the addition of binary coupling agents, the complex permittivity of flaky CIP is reduced, which is beneficial to impedance matching. The doping with 2wt% calcium stearate and 2ml titanate to flaky CIP has a minimum reflection loss peak of −13 dB at the thickness of 2 mm. It is noted that the effective absorption bandwidth (RL<-10dB) is up to 0.8GHz (1.8~2.6GHz). Moreover, the magnetic tangent loss of the samples can be significantly improved by the addition of binary coupling agents. Therefore, the surface modification of binary coupling agent can make flaky CIP get better impedance matching and absorbing performance in S band.

Preparation and Research of Coupling Agent Modified Organophilic Montmorillonite

2013 ◽  
Vol 634-638 ◽  
pp. 2238-2241
Author(s):  
Xiao Hua Gu ◽  
Jia Liang Zhou ◽  
Xiao Sheng Li ◽  
Bao Yun Xu
Keyword(s):  
Thermal Stability ◽  
Coupling Agent ◽  
Interlayer Spacing ◽  
Coupling Agents ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triphenyl Phosphonium ◽  
Ft Ir ◽  
Novel Method ◽  
Organophilic Montmorillonite

A novel method is proposed to modify montmorillonite with coupling agents and Hexadecyl triphenyl phosphonium bromide surfactants made by our group (named P-surfactant in the following). The structure of organophilic montmorillonite (OMMT) was investigated by FT-IR, XRD and TG. The FT-IR shows the coupling agents were inserted between the layers of MMT and reacted with –OH of MMT. The results of X-ray diffraction shows that the coupling agents were all intercalated into the layers of MMT. The interlayer spacing of montmorillonite increases to 4.00 nm, the effect of modification is well. The results of TG showed the thermal stability was better.

scholarly journals The Effect of 3-(Glycidoloxy Propyl) Trimethoxy Silane Concentration on Surface modification of SiO2 nanoparticles

2021 ◽  
Author(s):  
Hamed Bahramnia ◽  
Hamidreza Mohammadian Semnani ◽  
Ali Habibolahzadeh ◽  
Hassan Abdoos
Keyword(s):  
Surface Modification ◽  
Crystallite Size ◽  
Coupling Agent ◽  
Thermo Gravimetric Analysis ◽  
Sio2 Nanoparticles ◽  
Hydroxyl Group ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trimethoxy Silane

Abstract AbstractCoupling agent concentration plays a key role in functionalization of SiO2 nanoparticles as reinforcing particles.PurposeIn this study, the influence of 3-(glycidoloxy propyl) trimethoxy silane (GPTMS) concentration on functionalization of SiO2 nanoparticles, is experimentally investigated.MethodsThe functionalization of nano-silica were performed by 30, 50, 80 and 110 wt.% of GPTMS in order to find the optimal GPTMS concentration to complete the process. Fourier Transformation Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Thermo Gravimetric Analysis (TGA) and X-Ray Diffraction (XRD) characterized the pure and modified samples; then, the results were compared to each other to achieve the aim of the research.ResultsFTIR results confirmed the silanization proceed due to the silane absorption peak disappearing and shifting of the hydroxyl group bonds in to the amide bonds. This test showed that 30 wt.% GPTMS has not been sufficient for full functionalization of the NPs. According to FESEM images, it seems that the NPs were better modified by 80 wt.% GPTMS due to the least NPs aggregation and lack of coupling agent deposition on the NPs. Also, TGA illustrates that this sample has higher thermal stability because of lower weight loss (11.2%) in coupling agent decomposition temperature range: 130-380°C. Furthermore, X-Ray Diffraction confirmed the FESEM and TGA results about the mentioned sample due to its highest crystallite size (increase 26.64% in crystallite size in comparison with the pure sample).ConclusionSo, the 80 wt.% of GPTMS introduced as the optimal concentration for surface modification of SiO2 nanoparticles.

Prepared and Microwave-Absorption Properties of BN Coated Ni Nanocapsules

2010 ◽  
Vol 663-665 ◽  
pp. 1252-1255 ◽  
Author(s):  
Gui Mei Shi ◽  
Shu Lian ◽  
Ge Song ◽  
Jin Bing Zhang
Keyword(s):  
Reflection Loss ◽  
Electromagnetic Properties ◽  
Mechanochemical Reaction ◽  
Network Analyzer ◽  
Absorber Thickness ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
X Ray ◽  
Transmission Electron

BN coated Ni nanocapsules were prepared by arc evaporating Ni-B amorphous alloy powders synthesized by a mechanochemical reaction, and their microstructure, surface component as well as electromagnetic properties (2-18 GHz) were investigated by means of high-resolution transmission electron microscopy, X-ray diffraction , photoluminescence spectra (PL) and a network analyzer, respectively. The reflection loss R (dB) of the nanocapsules less than -20 dB was obtained in the frequency range of 4.3-18 GHz for an absorber thickness of 1.4-6 mm. An optimal reflection loss of -32.0 dB was reached at 13 GHz with an absorber thickness of 2 mm. The microwave absorptive mechanisms of BN-coated Ni nanocapsule absorbent were discussed.

scholarly journals Frequency and Temperature Dependent Dielectric Response of Fe3O4 Nano-crytallites

2014 ◽  
Vol 6 (3) ◽  
pp. 399-406 ◽  
Author(s):  
M. Z. Ansar ◽  
S. Atiq ◽  
K. Alamgir ◽  
S. Nadeem
Keyword(s):  
Magnetite Nanoparticles ◽  
Sol Gel ◽  
Dielectric Behavior ◽  
Tangent Loss ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Dielectric Tangent Loss ◽  
Auto Combustion ◽  
Combustion Technique

Magnetite nanoparticles have been prepared by using sol-gel auto combustion technique. The samples are prepared by using different concentrations of fuel. Structural characterization has been done using X-Ray diffraction technique and it was observed that fuel concentration can affect the structural properties of Magnetite nanoparticles. The dielectric properties for all the samples such as dielectric constant (??), dielectric tangent loss (tan ?) and dielectric loss factor (??) have been studied as a function of frequency and temperature in the range 10 Hz–20 MHz  and it was found that these nanoparticles can be used in microwave devices because of their good dielectric behavior. © 2014 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v6i3.17938 J. Sci. Res. 6 (3), 399-406 (2014)

Synthesis and Excellent Microwave Absorption Properties of ZnO/Fe3O4/MWCNTs Composites

NANO ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. 1650139 ◽  
Author(s):  
Lei Wang ◽  
Honglong Xing ◽  
Zhenfeng Liu ◽  
Ziyao Shen ◽  
Xiang Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Microwave Absorption ◽  
Photoelectron Spectroscopy ◽  
Wave Attenuation ◽  
Impedance Matching ◽  
Interfacial Polarization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Transmission Electron

ZnO nanocrystals were introduced into Fe3O4/MWCNTs composites to improve the impedance matching and electromagnetic (EM) wave attenuation of the system. The as-synthesized ZnO/Fe3O4/MWCNTs composites were characterized by X-ray diffraction, vibrating sample magnetometer, field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy. SEM and TEM images showed that Fe3O4 microspheres 100–200[Formula: see text]nm in size connected MWCNTs. Analysis of EM parameters revealed that the impedance matching of the ZnO/Fe3O4/MWCNTs composites was considerably improved after ZnO nanocrystals were introduced. The ZnO/Fe3O4/MWCNTs composites exhibited a highly efficient microwave absorption (MA) capacity within the tested frequency range of 2–18[Formula: see text]GHz. The optimal reflection loss of EM waves was [Formula: see text][Formula: see text]dB at 6.08[Formula: see text]GHz with an absorber thickness of 3.5[Formula: see text]mm. The excellent MA properties of the composites could be attributed to the improved impedance matching, interfacial polarization, and combined effects of dielectric and magnetic losses.

scholarly journals Phase, microstructure and microwave dielectric properties of Mg0:95Ni0:05Ti0:98Zr0:02O3 ceramics

2015 ◽  
Vol 33 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Abdul Manan ◽  
Dil Nawaz Khan ◽  
Atta Ullah ◽  
Arbab Safeer Ahmad
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Secondary Phase ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Scanning Electron

AbstractMg0:95Ni0:05Ti0:98Zr0:02O3 ceramics was prepared via conventional solid-state mixed-oxide route. The phase, microstructure and microwave dielectric properties of the sintered samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and a vector network analyzer. The microstructure comprised of circular and elongated plate-like grains. The semi quantitative analysis (EDS) of the circular and elongated grains revealed the existence of Mg0:95Ni0:05T2O5 as a secondary phase along with the parent Mg0:95Ni0:05Ti0:98Zr0:02O3 phase, which was consistent with the XRD findings. In the present study, εr ~17.1, Qufo~195855 ± 2550 GHz and τf ~ -46 ppm/K was achieved for the synthesized Mg0:95Ni0:05Ti0:98Zr0:02O3 ceramics sintered at 1325 °C for 4 h.

Surface Modification of 1-Butyl-3-Methylimidazolium Chloride -Treated Lignocellulosic Materials

2020 ◽  
Vol 1010 ◽  
pp. 526-531
Author(s):  
Asanah Radhi ◽  
Abdullah Othman ◽  
Muhammad Afif Aziz ◽  
Nik Raihan Nik Yusoff
Keyword(s):  
Electron Microscopy ◽  
Surface Modification ◽  
Functional Group ◽  
Hydroxyl Groups ◽  
Lignocellulosic Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexadecyl Trimethylammonium Bromide ◽  
Thermal Stability Of ◽  
Scanning Electron

Lignocellulosic materials are generally considered hydrophilic due to the high density of hydroxyl groups. The use of lignocellulosic materials in hydrophobic systems thus require surface modification. Therefore, in this study, cellulose (MCC) and sawdust (SD) have been pretreated with ionic liquid, 1-butyl-3-methylimidazolium chloride (BMIMCl) prior to surface modification with cationic surfactant, hexadecyl trimethylammonium bromide (CTAB). The effect of BMIMCl pretreatment prior to surface modification has been investigated. Crystallinity, functional group changes, morphology and thermal stability of the sawdust and cellulose upon BMIMCl pretreatment and surface modification have been studied using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric Analysis (TGA). XRD results showed that the structure of lignocellulosic materials became more amorphous upon pretreatment with BMIMCl. FTIR results indicated that the modification of lignocellulosic is more efficient in BMIMCl-pretreated samples. Percentage of decomposition is higher for the BMIMCl-pretreated and CTAB modified samples.

Microwave Absorption Performance of La0.7 Sr0.3 MnO3 with Different Sintering Temperatures

2011 ◽  
Vol 415-417 ◽  
pp. 1399-1402 ◽  
Author(s):  
Shu Yuan Zhang ◽  
Quan Xi Cao
Keyword(s):  
Low Frequency ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Pure Perovskite Structure ◽  
X Ray ◽  
Different Temperatures ◽  
Absorption Performance ◽  
Microwave Absorption Performance ◽  
Traditional Solid State Method

La 0.7 Sr 0.3 MnO 3 powders have been synthesized at different temperatures by the traditional solid state method. The crystal structures have been characterized by X-ray diffraction (XRD). The electromagnetic parameters were measured by vector network analyzer (VNA) within the frequency range of 5.85-18GHz. It’s found that the pure perovskite structure has been obtained at the temperature of 1000°C. The bandwidth for R<-6dB became thinner with the sintering temperature’s increase from 1000°C to 1150°C, and the absorbing peak moves to the higher frequency first and low frequency then, the absorbing peak is enhanced first and weakened then.

Surface Modification of Parylene C Film and Application

2013 ◽  
Vol 750-752 ◽  
pp. 1887-1890
Author(s):  
Li Sheng Zhang ◽  
Yuan Lin Zhou ◽  
Yang Guo ◽  
Ye Yang
Keyword(s):  
Surface Modification ◽  
Benzene Ring ◽  
Film Surface ◽  
Attenuated Total Reflection ◽  
X Ray Diffraction ◽  
Parylene C ◽  
X Ray ◽  
Fourier Transformation Infrared Spectroscopy ◽  
Function Group ◽  
Cl Atom

In this article, we report the surface modification results of Parylene C Film by solution of sodium naphthalene complex and its application. In this work, the function group and the crystal structure of the film were characterized separately with Attenuated Total Reflection Fourier transformation infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD).The result of test shows that the bond of carbon (C) and chlorine (Cl) is damaged; The crystalline of the film reduces, and the NaCl crystal exist on the film surface. The surface energy of the film is increased from 28.64mJ/m2 to 41.48mJ/m2, and the shearing tension of modified film was reached over 212.8kPa.The generalized analysis result indicated that nucleophilic reagent destructs the C-Cl bond on the benzene ring, the chlorine (Cl) atom on the benzene ring and the sodium ion in modified reagent forms the sodium chloride which adheres to the film surface.

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