scholarly journals High-Temperature Dielectric and Microwave Absorption Property of Atmospheric Plasma Sprayed Al2O3-MoSi2-Cu Composite Coating

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1029
Author(s):  
Cheng Gao ◽  
Yangsheng Jiang ◽  
Dayong Cai ◽  
Jinyong Xu ◽  
Jia Ding
Keyword(s):  
High Temperature ◽  
Microwave Absorption ◽  
Temperature Stability ◽  
Atmospheric Plasma ◽  
High Temperature Stability ◽  
Atom Diffusion ◽  
In Situ Xrd ◽  
Air Atmosphere ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Al2O3-MoSi2 coating has excellent high-temperature stability. On this basis, Al2O3-MoSi2-Cu composite high-temperature absorbing coating was prepared by atmospheric plasma spraying method. The phase transition characteristics of Al2O3-MoSi2-Cu spraying feedstock under high temperatures were analyzed by thermogravimetric test, the phase analysis of coating was performed by an in situ XRD test at different temperatures, and the microstructure of the coating was characterized by SEM. The test results of high-temperature microwave absorption performance show that, in high-temperature air atmosphere, the Cu in the coating is gradually transformed into Cu2O by oxygen atom diffusion, and the microwave absorption performance of the coating gradually increases with the increase in temperature. The 1.7 mm-thick coating at 500 °C has the best absorbing performance with a reflection loss (RL) value of −17.96 dB and an effective absorbing bandwidth (RL < −10 dB) in X-band of 2.42 GHz. The prepared Al2O3-MoSi2-Cu composite high-temperature absorbing coating takes into account the dual advantages of high-temperature stability and high-temperature absorbing properties.

High Temperature Stability of MGCs Gas Turbine Components in Air and Combustion Gas Flow Environments

2004 ◽  
Author(s):  
Narihito Nakagawa ◽  
Hideki Ohtsubo ◽  
Kohji Shibata ◽  
Atsuyuki Mitani ◽  
Kazutoshi Shimizu ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Flow ◽  
Temperature Stability ◽  
High Temperature Strength ◽  
High Temperature Stability ◽  
Combustion Gas ◽  
Air Atmosphere ◽  
Low Nox Emission ◽  
Very High

Melt growth composites (MGCs) have a unique microstructure, in which continuous networks of single-crystal phases interpenetrate without grain boundaries. Therefore, the MGCs have excellent high-temperature strength characteristics, creep resistance, oxidation resistance and thermal stability in an air atmosphere at very high temperature. To achieve ultra-high thermal efficiency and low NOx emission for gas turbine systems, non-cooled turbine nozzle vanes and heat shield panels of combustor liners has been fabricated on an experimental basis. These components are thermally stable after heat treatment at 1700°C for 1000 hours in an air atmosphere. In addition, we have just started the exposure tests to evaluate the influence of combustion gas flow environment on MGCs.

scholarly journals Tunable Narrowband Silicon-Based Thermal Emitter with Excellent High-Temperature Stability Fabricated by Lithography-Free Methods

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1814
Author(s):  
Guozhi Hou ◽  
Qingyuan Wang ◽  
Yu Zhu ◽  
Zhangbo Lu ◽  
Jun Xu ◽  
...  
Keyword(s):  
High Temperature ◽  
Absorption Spectra ◽  
Fdtd Method ◽  
Temperature Stability ◽  
High Energy ◽  
Structure Design ◽  
Bragg Reflector ◽  
High Temperature Stability ◽  
Absorption Performance ◽  
Thermal Emitter

Thermal emitters with properties of wavelength-selective and narrowband have been highly sought after for a variety of potential applications due to their high energy efficiency in the mid-infrared spectral range. In this study, we theoretically and experimentally demonstrate the tunable narrowband thermal emitter based on fully planar Si-W-SiN/SiNO multilayer, which is realized by the excitation of Tamm plasmon polaritons between a W layer and a SiN/SiNO-distributed Bragg reflector. In conjunction with electromagnetic simulations by the FDTD method, the optimum structure design of the emitter is implemented by 2.5 periods of DBR structure, and the corresponding emitter exhibits the nearly perfect narrowband absorption performance at the resonance wavelength and suppressed absorption performance in long wave range. Additionally, the narrowband absorption peak is insensitive to polarization mode and has a considerable angular tolerance of incident light. Furthermore, the actual high-quality Si-W-SiN/SiNO emitters are fabricated through lithography-free methods including magnetron sputtering and PECVD technology. The experimental absorption spectra of optimized emitters are found to be in good agreement with the simulated absorption spectra, showing the tunable narrowband absorption with all peak values of over 95%. Remarkably, the fabricated Si-W-SiN/SiNO emitter presents excellent high-temperature stability for several heating/cooling cycles confirmed up to 1200 K in Ar ambient. This easy-to-fabricate and tunable narrowband refractory emitter paves the way for practical designs in various photonic and thermal applications, such as thermophotovoltaic and IR radiative heaters.

Ni-decorated SiC powders: Enhanced high-temperature dielectric properties and microwave absorption performance

2013 ◽  
Vol 237 ◽  
pp. 309-313 ◽  
Author(s):  
Jie Yuan ◽  
Hui-Jing Yang ◽  
Zhi-Ling Hou ◽  
Wei-Li Song ◽  
Hui Xu ◽  
...  
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Microwave Absorption ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Negative imaginary parts of complex permeability and microwave absorption performance of core double-shelled FeCo/C/Fe2.5Cr0.5Se4 nanocomposites

RSC Advances ◽  
2016 ◽  
Vol 6 (77) ◽  
pp. 73020-73027 ◽  
Author(s):  
D. Li ◽  
Y. Feng ◽  
D. S. Pan ◽  
L. W. Jiang ◽  
Z. M. Dai ◽  
...  
Keyword(s):  
High Temperature ◽  
Microwave Absorption ◽  
Chemical Method ◽  
Arc Discharge ◽  
Complex Permeability ◽  
Discharge Process ◽  
High Temperature Solution ◽  
Temperature Solution ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Cactus-shaped core double-shelled FeCo/C/Fe2.5Cr0.5Se4 nanostructures with a spiky surface were prepared by combining an arc-discharge process with a high-temperature solution chemical method.

High-temperature annealing of an iron microplate with excellent microwave absorption performance and its direct micromagnetic analysis by electron holography and Lorentz microscopy

2017 ◽  
Vol 5 (24) ◽  
pp. 6047-6053 ◽  
Author(s):  
Wenbin You ◽  
Wen She ◽  
Zhengwang Liu ◽  
Han Bi ◽  
Renchao Che
Keyword(s):  
Magnetic Property ◽  
High Temperature ◽  
Microwave Absorption ◽  
Electron Holography ◽  
High Temperature Annealing ◽  
Lorentz Microscopy ◽  
Special Morphology ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Microplate iron exhibits excellent microwave absorption performance because of its special morphology and optimization of its magnetic property.

scholarly journals Flexible Fe3Si/SiC ultrathin hybrid fiber mats with designable microwave absorption performance

RSC Advances ◽  
2018 ◽  
Vol 8 (59) ◽  
pp. 33574-33582 ◽  
Author(s):  
Yi Hou ◽  
Yani Zhang ◽  
Xiaoqing Du ◽  
Yong Yang ◽  
Chaoran Deng ◽  
...  
Keyword(s):  
High Temperature ◽  
Microwave Absorption ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Hybrid Fiber ◽  
Fiber Mats ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Flexible Fe3Si/SiC ultrathin fiber mats have been fabricated by electrospinning and high temperature treatment (1400 °C) using polycarbosilane (PCS) and ferric acetylacetonate (Fe(acac)3) as precursors.

scholarly journals Thin and temperature resistant TiO2-Sr1-xLaxTiO3 (x=0.1~0.3) composite ceramics for microwave absorption in the X-band

2021 ◽  
Author(s):  
Yingying Zhou ◽  
Qinlong Wen ◽  
Chaoqun Yang ◽  
Zhaowen Ren ◽  
Yuanyuan Lu ◽  
...  
Keyword(s):  
High Temperature ◽  
Microwave Absorption ◽  
High Performance ◽  
Temperature Stability ◽  
Absorption Efficiency ◽  
Material System ◽  
High Temperature Stability ◽  
X Ray ◽  
Novel Material ◽  
Composition Structure

Abstract Recently, high-temperature stability is a challenge in a number of microwave absorption materials. Hence, researchers are still searching for a novel material system preferably with a high-temperature resistance to be applied in the field of microwave absorption. Here, in the current study, toward this aim, lanthanum (La) doped strontium titanate (SrTiO 3 ) blended with TiO 2 were fabricated by hot-press sintering in vacuum. The as-prepared samples are denoted as TiO 2 -Sr 1- x La x TiO 3 with x varying from 0.1 to 0.3 in steps of 0.1. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), and microwave vector network analyzer were carried on to study their morphology, phase composition, structure, electromagnetic and microwave absorption properties, respectively. It is revealed that the La atom was efficiently doped at the Sr-site in SrTiO 3 . Benefiting from the tunability of its dielectric and impedance properties, TiO 2 -Sr 1- x La x TiO 3 can be utilized in a highly efficient way to absorb microwave radiations with a decent design. Results illustrated that TiO 2 -Sr 1- x La x TiO 3 ( x =0.2) with a thickness of only 0.42 mm exhibits a high microwave absorption efficiency of -40.89 dB and can achieve a 2.82 GHz bandwidth of reflection loss value below -5 dB. Thus, TiO 2 -Sr 1- x La x TiO 3 composites ceramics can be served as an opening opportunity for the application of high-temperature stability and tunable high-performance effectiveness microwave absorption materials in stealth technology and information security.

scholarly journals Conductive, Superhydrophobic, and Microwave-Absorbing Cotton Fabric by Dip-Coating of Aqueous Silk Nanofibers Stabilized MWCNTs and Octadecanoyl Chain Bonding

2021 ◽  
Author(s):  
Ling Liu ◽  
Mingyuan Wu ◽  
Qingyun Wu ◽  
Jiuyi Liu ◽  
Jianjun Yang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Microwave Absorption ◽  
Cotton Fabric ◽  
Active Sites ◽  
Dip Coating ◽  
Transmission Electron Microscopy Micrographs ◽  
Coating Adhesion ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Abstract A facile dip-coating method to endow cotton fabric (CF) with satisfactory conductivity, superhydrophobicity and microwave absorption performance was proposed based on the combination of multi-walled carbon nanotubes (MWCNTs) incorporation and hydrophobic octadecanoyl chain bonding. The entanglement and bundling of MWCNTs induced by the particularly high aspect ratio and high interaction energy renders homogeneous dispersion of MWCNTs a challenging. The durable coating adhesion of MWCNTs on hydrophilic CF remains the other challenge due to the absence of strong interactions with intrinsic hydrophobic MWCNTs. In this work, silk nanofibers (SNFs) were synthesized by degrading silk at high temperature, which was adopted as dispersant to prepare individually dispersed MWCNTs via ultrasonication and homogenization processes. The coating adhesion of MWCNTs to CF (MWCNTs-CF) was enhanced via dipping coating and thermal treatment induced chemical immobilization cycles. Octadecanoyl chain-tethered MWCNTs-CF (C18-MWCNTs-CF) was manufactured by further treatment with stearoyl chloride to achieve superhydrophobicity. The scanning and transmission electron microscopy micrographs demonstrated that the aggregates of MWCNTs were successfully de-bundled into individually dispersed nanotubes by taking advantages of the high π-π interaction and electrostatic repulsive interactions between MWCNTs and SNFs. SNFs has the superiority of chemical bonding with CF at high temperature and providing active sites for subsequent hydrophobic treatment. The electrical conductivity, surface properties, thermal stability, mechanical properties, and microwave absorption performance of the CF samples were evaluated systematically. Compared with pristine CF (1.04🞩1010 Ω), the C18-MWCNTs-CF exhibited excellent conductive property with surface resistance reaching 55 Ω when the loaded MWCNTs on CF were 247.5 mg/g in the case of 3 dipping-drying cycles and possessed a relatively greater microwave absorption performance of -36.08 dB at 9.28 GHz with merely 2.7 mm thickness. Compared with pristine CF, C18-MWCNTs-CF exhibited superhydrophobicity with the WCA increasing from 26° to 150° even after 20 scratching cycles due to the combination of facile octadecanoyl group tethering and the increased surface roughness. The biodegradable and recyclable C18-MWCNTs-CF exhibited reasonable electrical conductivity, superhydrophobicity and microwave absorption that promises an ideal application prospect in the field of smart textile and wearable electronic devices.

Sign in / Sign up

Export Citation Format

Share Document