scholarly journals Barium titanate flakes based composites for microwave absorbing applications

2013 ◽  
Vol 7 (4) ◽  
pp. 189-193 ◽  
Author(s):  
Raj Jain ◽  
Ashish Dubey ◽  
Amit Soni ◽  
Sanjiv Gupta ◽  
Trilok Shami
Keyword(s):  
Barium Titanate ◽  
Reflection Loss ◽  
Composite Laminates ◽  
Sol Gel ◽  
Tape Casting ◽  
Weight Ratio ◽  
Single Layer ◽  
Wide Frequency Range ◽  
Nano Particles ◽  
Electromagnetic Properties

Barium titanate (BT) has attained research focus in recent past owing to considering its high dielectric constant and stealth capabilities in microwave region. Shape effects of BT viz. powder, micron size flakes, nano particles and nanotubes have been studied vastly for its stealth capabilities. Present study aims at the preparation of millimetric size barium titanate flakes (BTFs) via controlled sol-gel process followed by tape casting. BTFs were mixed in varied weight ratio (50-90 wt.%) with polyurethane resin to fabricate composite laminates. Electromagnetic properties measurement in X and Ku band revealed high values of real and imaginary permittivity. Reflection loss measurements demonstrated more than 20 dB loss in wide frequency range (11.4-13.6 GHz). For single layer microwave absorber, reflection loss values have been calculated and it is observed that calculated and measured reflection loss values are in good agreement to each other. Developed material can find applications in broadband radar signature reduction.

scholarly journals Electromagnetic Properties Performance of MWCNTs/Polyester Composites in X-band

2018 ◽  
Vol 150 ◽  
pp. 06014 ◽  
Author(s):  
Y. S. Lee ◽  
F. H. Wee ◽  
K. Y. You ◽  
C. Y. Lee ◽  
Y. Y. Lee ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Weight Ratio ◽  
Electromagnetic Properties ◽  
Band Frequency ◽  
Microwave Absorbing Materials ◽  
X Band ◽  
Line Theory ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this paper presents nano-composites based on polyester (PE) matrix with multi-walled carbon nanotubes (MWCNTs) as fillers have been developed for microwave absorbing materials. The MWCNTs/PE composite samples were fabricated with different weight ratio of MWCNTs (3 wt%, 5 wt%, and 10 wt%). The electromagnetic properties of different MWCNTs/PE composite have been determined by using rectangular waveguide technique and Agilent material measurement software. Moreover, the reflection loss (microwave absorption) of MWCNTs/PE composite have been calculated based on the basis of transmission line theory. The performance of electromagnetic properties and microwave absorption of MWCNTs/PE composite were analyzed in X-band frequency. The dielectric loss properties of the composite are increse with increasing in MWCNTs weight ratio. The microwave absorption results show that such 3 wt% MWCNTs/PE composites sample with 4 mm thickness has achieved less than -10 dB values (< 90 % microwave absorption) of reflection loss.

scholarly journals Effect of different permeability on electromagnetic properties of absorbing materials

2018 ◽  
Vol 197 ◽  
pp. 02015 ◽  
Author(s):  
Riser Fahdiran ◽  
Yuliyanti Dwi Utami ◽  
Erfan Handoko
Keyword(s):  
Transmission Line ◽  
Reflection Loss ◽  
Single Layer ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Transmission Line Theory ◽  
Microwave Frequencies ◽  
Microwave Absorbing Properties ◽  
Absorbing Materials ◽  
Line Theory

In this study, we have simulated and investigated electromagnetic properties of six types materials using a single layer metal backed absorber model that were determined at microwave frequencies 8.2 up to12.4 GHz. The reflection loss was simulated for different thicknesses in the range of 0.85 to 1.05 mm based on the relative complex permeability and permittivity referring to transmission line theory. The optimal microwave absorbing properties was be resulted by A3 sample. The minimum RL of −23.84 dB can be obtained at 10.72 GHz with thin thickness of 0.95 mm. This method paves a new avenue to design magnetic and dielectric absorbing materials.

Microelectronics Packaging Application using post-LTCC technology

2011 ◽  
Vol 2011 (CICMT) ◽  
pp. 000127-000129
Author(s):  
Yoshihiko IMANAKA ◽  
Hideyuki AMADA ◽  
Fumiaki KUMASAKA
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Room Temperature ◽  
Electronic Devices ◽  
Tape Casting ◽  
Rapid Evolution ◽  
Lithium Ion ◽  
Aerosol Deposition ◽  
Nano Particles ◽  
Degree Of Crystallinity

The rapid evolution in electronic equipment has created a demand for advanced devices that are flexible, thin, and light in weight. This demand is driving the development of flexible and stretchable electronic devices as a core technology. To produce wearable computers, we need to fabricate functional membranes that contain passive devices such as capacitors and resistors on resin sheets at low temperatures. These sheets can then serve as mounting boards for various electronic devices. By improving the technique for room-temperature aerosol deposition (ASD) of a ceramic material (post-LTCC technology), we have established a technology for forming a dielectric inorganic film with an excellent degree of crystallinity and favorable electric properties for use in the production of flexible and stretchable electronic devices on a polyimide sheet. In the barium titanate film produced by the deposition on a polyimide sheet, a closely packed film with a high degree of sealing was formed by means of structure control to establish large-particle anchors, measuring about 100 nm in diameter, at the interface between the ceramic film and the polyimide sheet. The maximum dielectric constant of a film of barium titanate formed on the polyimide sheet by using the improved aerosol-deposition was 350 .By using this method to form a three-dimensional capillary structure inside a film, we produced a capacitor film with an apparent dielectric constant of 40,000 at room temperature. We also demonstrate cathode films for quick-charging lithium ion batteries. To achieve rapid charging, it is necessary to improve the speed of the chemical reaction between the cathode material and the electrolyte. Our process, however, does not require any unnecessary additive, such as a binder, unlike conventional tape casting method, and forms a film consisting of nano-particles of a high crystallinity, and is therefore effective for rapid charging.

scholarly journals Tailoring Mesoporous Titania Features by Ultrasound-Assisted Sol-Gel Technique: Effect of Surfactant/Titania Precursor Weight Ratio

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1263
Author(s):  
Elvira Mahu ◽  
Cristina Giorgiana Coromelci ◽  
Doina Lutic ◽  
Iuliean Vasile Asaftei ◽  
Liviu Sacarescu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Weight Ratio ◽  
Soft Template ◽  
Synthesis Process ◽  
Mesoporous Titania ◽  
Cavitation Effect ◽  
Titania Precursor ◽  
Gel Technique ◽  
Ultrasound Assisted

A mesoporous titania structure has been prepared using the ultrasound-assisted sol-gel technique in order to find out a way to tailor its structure. The TiO2 obtained was compared to the same version of titania but synthesized by a conventional sol-gel method with the objective of understanding the effect of ultrasound in the synthesis process. All synthesis experiments were focused on the preparation of a titania photocatalyst. Thus, the anatase photocatalytic active phase of titania was proven by X-ray diffraction. Additionally, the ultrasonation treatment proved to increase the crystallinity of titania samples, being one of the requirements to having good photocatalytic activity for titania. The influence of surfactant/titania precursor weight ratio on the structural (XRD), textural (N2-sorption measurements), morphological (TEM), surface chemistry (FTIR) and optical properties (UVDR) was investigated. It was observed that the crystallite size, specific surface area, band gap energy and even photocatalytic activity was affected by the synergism occurring between cavitation effect and the surfactant/titania precursor weight ratio. The study yielded interesting great results that could be considered for further application of ultrasound to tailor mesoporous titania features via sol-gel soft template synthesis, against conventional sol-gel process.

Manufacturing Processes of Solid Oxide Fuel Cell Components

2007 ◽  
Vol 336-338 ◽  
pp. 498-501
Author(s):  
Xian Feng Jiang ◽  
Min Fang Han ◽  
Su Ping Peng
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Screen Printing ◽  
Sol Gel ◽  
Tape Casting ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Cell Components ◽  
One Step ◽  
Made In

The all processes for manufacturing materials parts of solid oxide fuel cell (SOFC) are discussed in the paper. The films are made in one step by the ways of APS, VPS, EVD, which are usually used to produce the electrolyte and interconnect. The films are thin and good gas-resistance, but with relatively high cost. All parts of SOFC are made by the following ways, such as sol-gel, tape casting, tape calendaring and screen printing, which are suitable for manufacturing samples in industry with the cheapest process by co-sintered together ways.

scholarly journals Loading Effect of Sol-Gel Derived Barium Hexaferrite on Magnetic Polymer Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 558
Author(s):  
Thanida Charoensuk ◽  
Wannisa Thongsamrit ◽  
Chesta Ruttanapun ◽  
Pongsakorn Jantaratana ◽  
Chitnarong Sirisathitkul
Keyword(s):  
Polymer Composites ◽  
Sol Gel ◽  
Weight Ratio ◽  
Barium Hexaferrite ◽  
Acrylonitrile Butadiene Styrene ◽  
Combustion Method ◽  
Casting Method ◽  
Auto Combustion ◽  
Solution Casting Method ◽  
Butadiene Styrene

Solution–processing methods were investigated as viable alternatives to produce the polymer-bonded barium hexaferrite (BaM). BaM powders were first synthesized by using the sol-gel auto-combustion method. While the ignition period in two synthesis batches varied, the morphology of hexagonal microplates and nanorods, as well as magnetic properties, were reproduced. To prepare magnetic polymer composites, these BaM powders were then incorporated into the acrylonitrile-butadiene-styrene (ABS) matrix with a weight ratio of 80:20, 70:30, and 60:40 by using the solution casting method. Magnetizations were linearly decreased with a reduction in ferrite loading. Compared to the BaM loose powders and pressed pellet, both remanent and saturation magnetizations were lower and gave rise to comparable values of the squareness. The squareness around 0.5 of BaM samples and their composites revealed the isotropic alignment. Interestingly, the coercivity was significantly increased from 1727–1776 Oe in loose BaM powders to 1874–2052 Oe for the BaM-ABS composites. These composites have potential to be implemented in the additive manufacturing of rare-earth-free magnets.

A study on the electromagnetic properties of graphite/bismuth/bismuth oxide-coated composites

2021 ◽  
pp. 004051752199434
Author(s):  
Yuanjun Liu ◽  
Yanfeng Yang
Keyword(s):  
Mechanical Property ◽  
Dielectric Constant ◽  
Bismuth Oxide ◽  
Control Variable ◽  
Single Layer ◽  
Polarization Property ◽  
Electromagnetic Properties ◽  
Shielding Effectiveness ◽  
Absorbing Property ◽  
Layer Coating

Coating is a commonly used process for the preparation of protective textiles. In this study, the absorbing coated composite material was prepared by a coating process, using plain weave polyester/cotton fabric as the base fabric, PU-2540 polyurethane as the binder, and graphite, bismuth and bismuth oxide as the functional particles. The effects of the content of functional particles and the ratio of functional particles on the dielectric constant, reflection loss, shielding effectiveness, and tensile strength of the single-layer coating composites were studied using the control variable method. The results showed that when the frequency was 1–1000 MHz, the real and imaginary parts of the dielectric constant, the tangential value of the loss angle, and the tensile value increased with the increase of the coating content, and the polarization, loss and attenuation property, and mechanical property of the electromagnetic wave were enhanced. When graphite, bismuth, and bismuth oxide was mixed at the ratio of 9:0:0 in weight, the polarization property was the best. When mixed at the ratio of 6:1:2 in weight, the loss performance and attenuation ability were the best. When mixed at the ratio of 6:3:0 in weight, the absorbing property and mechanical property were the best. When mixed at the ratio of 6:2:1 in weight, the shielding property was the best.

scholarly journals Synergy Effects in Electromagnetic Properties of Phosphate Ceramics with Silicon Carbide Whiskers and Carbon Nanotubes

2019 ◽  
Vol 9 (20) ◽  
pp. 4388 ◽  
Author(s):  
Artyom Plyushch ◽  
Jan Macutkevič ◽  
Polina Kuzhir ◽  
Aliaksei Sokal ◽  
Konstantin Lapko ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Silicon Carbide ◽  
Wide Frequency Range ◽  
Electromagnetic Properties ◽  
Aluminium Phosphate ◽  
Silicon Carbide Whiskers ◽  
Synergy Effects ◽  
Multi Walled Carbon Nanotubes ◽  
The Difference ◽  
Walled Carbon Nanotubes

Hybrid composite materials based on an aluminium phosphate matrix with silicon carbide whiskers and multi-walled carbon nanotubes were studied in a wide frequency range (20 Hz to 36 GHz). It was demonstrated, that the addition of the silicon carbide whiskers enhances the dielectric permittivity and conductivity. This was explained by the difference in tunnelling parameters. Hybrid ceramics with nanotubes and whiskers also exhibits substantially improved electromagnetic shielding properties. The hybrid ceramics with 10 wt. % silicon carbide whiskers and a 1 mm thick 1.5 wt. % carbon nanotube layer, show higher than 50% absorption of electromagnetic radiation.

Synergistic Effect of Eu3+ and Sm3+ Co-Doping on Photocatalytic Activity of TiO2 Nanoparticles

2011 ◽  
Vol 197-198 ◽  
pp. 891-894 ◽  
Author(s):  
Cheng Zhi Jiang ◽  
Xu Dong Lu
Keyword(s):  
Photocatalytic Activity ◽  
Synergistic Effect ◽  
Sol Gel ◽  
Blue Shift ◽  
Nano Particles ◽  
Absorption Profile ◽  
Co Doping ◽  
The Matrix ◽  
Co Doped ◽  
The Eu

Pure TiO2, Eu3+and Sm3+co-doping TiO2composite nanoparticles have been prepared by sol-gel method and characterized by the techniques such as XRD, SEM and DRS. The photocatalytic degradation of methylene blue (MB) in aqueous solution was used as a probe reaction to evaluate their photocatalytic activity. The matrix distortion of TiO2nano-particles increases after co-doping of Eu3+and Sm3+and a blue-shift of the absorption profile are clearly observed. The results show that co-doping of Eu3+and Sm3+inhibits the phase transformation of TiO2from anatase to rutile, decreases the diameter of TiO2nano-particles and significantly enhance the photocatalytic activity of TiO2. The Eu3+and Sm3+co-doped into TiO2nano-particles exert a synergistic effect on their photocatalytic activity.

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