Preparation and Microwave Absorbing Properties of Iron Oxides/Carbon Nanotubes Compounds

2012 ◽  
Vol 548 ◽  
pp. 133-137
Author(s):  
Chuan Guo Ma ◽  
Hai Jun Zheng ◽  
Xiao Ming Li ◽  
Liang Gao
Keyword(s):  
Thermal Decomposition ◽  
Iron Oxides ◽  
Nitrate Solution ◽  
Decomposition Temperature ◽  
Iron Nitrate ◽  
Microwave Absorbing Properties ◽  
Valence States ◽  
Different Temperatures ◽  
Microwave Absorbing ◽  
Absorbing Property

A Series of iron oxides/CNTs compounds were prepared using a method of impregnation with iron nitrate solution and followed thermal decomposition. The compounds were characterized by the means of scanning electronic microscope, X-ray diffraction and thermogravimetic analysis. The dielectric and microwave-absorbing properties of EP composites containing the different compounds were further measured in a specific frequency range. The results show that: CNTs show reduction at a high temperature, and can make products of the thermal decomposition of iron nitrate produce iron oxide nanoparticles with different valence states at different temperatures. With increasing decomposition temperature, the iron oxides in CNTs composites in turn are Fe2O3, Fe3O4, FeO and Fe. Compared with pure CNTs, these iron oxides/CNTs composites have better microwave absorbing properties in the wavebands of 7.5GHz ~ 15GHz and 26.5GHz ~ 40GHz. Among those iron oxides /CNTs compounds, Fe3O4/CNTs compound has the best microwave absorbing property.

Effect of Structure Modification on the Microwave Absorbing Performance of Carbon Foams

2011 ◽  
Vol 197-198 ◽  
pp. 536-539 ◽  
Author(s):  
Zhi Gang Fang ◽  
Yu Xin Gao ◽  
Chun Fang
Keyword(s):  
Electric Conductivity ◽  
Carbon Foam ◽  
Structure Design ◽  
Structure Modification ◽  
Replication Process ◽  
Microwave Absorbing Properties ◽  
Carbon Foams ◽  
Microwave Absorbing Property ◽  
Microwave Absorbing ◽  
Absorbing Property

Carbon foams were prepared by a polymer sponge replication process and their microwave absorbing properties were investigated. The electric conductivity of carbon foam has a direct effect on its microwave absorbing property, as the carbon foam with a medium electric conductivity of 0.46S/m has got a relatively excellent microwave absorbing property and demonstrated a characteristic of broadband absorption. Some structure modification has been made on carbon foams to fruther imrove their microwave absorbing performance. The result shows that making slots, especially gradient slots on the surface of carbon foams can greatly improve their microwave absorbing properties, while the reflection coefficients for a three-layered carbon foam structure exceeds -10dB with the combination effect of multilayer structure design and parameters gradient variatioin in the whole frequency range of 2.6-18GHz, which is usually to be considered as the practical application standard for microwave absorbing materials.

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.

Acute Inhalation Toxicity in Rats Exposed to Thermal Degradation Products of Hydraulic Fluids Type C

1994 ◽  
Vol 12 (5) ◽  
pp. 411-423 ◽  
Author(s):  
J. Van Dam ◽  
P. Daenens ◽  
E.K. Yerbeken
Keyword(s):  
Thermal Decomposition ◽  
Quantitative Data ◽  
Degradation Products ◽  
Decomposition Temperature ◽  
Inhalation Toxicity ◽  
Histological Damage ◽  
Safety And Health ◽  
Hydraulic Fluids ◽  
Different Temperatures ◽  
Type C

The acute inhalation toxicity of the thermal decomposition prod ucts of Hydraulic fluids type C was assessed in rats. These fluids consist of a mixture of water, ethylene glycol, polyalkylene glycol and some minor addi tives. Glissosafe® 610 was used as a model. Animals were exposed for one hour to atmospheres resulting from spraying the fluid on a plate heated to 500 °C, 600 ° C or 700°C. They were followed for fourteen days after exposure following the prescriptions of the Sixth Report of the Safety and Health Commission of the European Community. Additional tests were done to follow the evolution of histological damage at one, two, three, five and seven days after exposure to the different temperatures. These results were compared with some quantitative data of the major decomposition products. No mortality occurred. Only slight and transient respiratory discomfort was noticed during exposure due to the presence of sensory irritating products. The effects on growth were virtually nil, except for some slight initial retardation during the first day post-exposure. Histological damage was most pronounced at a decomposition temperature of 500°C. These results correlated with the quantitative data of the sensory irritating components. Out of this thermal decomposition mixture, formaldehyde seems to contribute most to the toxic ef fects.

Preparation of YBCO Superconducting Thin Film by Pulsed Thermal Decomposition of Ultrasonic-Misted Nitrate Solution

1997 ◽  
Vol 495 ◽  
Author(s):  
Junichi. Kinugasa ◽  
Akimitsu. Hatta ◽  
Toshimichi. Ito
Keyword(s):  
Thermal Decomposition ◽  
Rutherford Backscattering Spectrometry ◽  
Local Heating ◽  
Nitrate Solution ◽  
Diffraction Method ◽  
Decomposition Temperature ◽  
X Ray Diffraction ◽  
Superconducting Thin Film ◽  
New Material ◽  
Free Films

ABSTRACTYBa2Cu3O7-x superconducting thin films have been prepared by a new material preparation method, namely pulsed thermal decomposition of ultrasonic-misted nitrate solution. The prepared films have been studied by using powder X-ray diffraction method, scanning electron microscopy and Rutherford backscattering spectrometry. The results obtained indicate (1) that by local heating of the substrate with an infrared lamp, c-axis oriented YBa2Cu3O7-x films can be deposited without segregation of impurity phases, (2) that a high decomposition temperature is necessary to increase flatness of thin YBa2Cu3O7-x films although a sufficient margin temperature is required to obtain impurity-phase-free films, and (3) that the efficiency of the process increases if the adhesion is large between the deposited film and the substrate.

PANI / MWNTs / EP Composite Microwave Absorbing Coatings Dielectrical and Microwave Absorbing Properties Analysis

2013 ◽  
Vol 303-306 ◽  
pp. 2477-2480 ◽  
Author(s):  
Chong Guang Zang ◽  
Xian Peng Cao
Keyword(s):  
Reflection Loss ◽  
In Situ Polymerization ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing Materials ◽  
Multi Walled Carbon Nanotubes ◽  
Properties Of Materials ◽  
Microwave Absorbing ◽  
Absorbing Property ◽  
Walled Carbon Nanotubes

In this paper, the polyaniline (PANI) coated multi-walled carbon nanotubes (MWNTs) was prepared in situ polymerization. Adding PANI/MWNTs into epoxy resin（EP）, we got PANI / MWNTs / EP composite microwave absorbing materials. Through testing permittivity 、permeability and reflection loss of materials, the paper showed the effect of PANI/MWNTS to the dielectrical and microwave absorbing properties of materials.The results showed： PANI/MWNTs had great effect on dielectrical and microwave absorbing properties of materials. But the imaginary permeability was close to 0. That indicated that it mainly consumed electromagnetic wave by dielectric loss. In 200-1000MHZ, materials had better absorbing property and lower reflection loss (-13.6).

scholarly journals Preparation and microwave-absorbing property of BaFe12O19 nanoparticles and BaFe12O19/Fe3C/CNTs composites

RSC Advances ◽  
2015 ◽  
Vol 5 (111) ◽  
pp. 91665-91669 ◽  
Author(s):  
Liangjun Yin ◽  
Tong Chen ◽  
Shiyu Liu ◽  
Yuqi Gao ◽  
Biao Wu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Great Improvement ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Chemical Vapor Deposition Process ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing Property ◽  
Microwave Absorbing ◽  
Absorbing Property

A novel kind of BaFe12O19/Fe3C/CNTs composite was developed by the acetylene chemical vapor deposition process. The composites perform great improvement in the microwave absorbing properties compared with pure BaFe12O19 ferrite in 2–18 GHz range.

Microwave Absorbing Properties of Carbon Fibers Modified with BN/SiC Composite Coatings

2014 ◽  
Vol 29 (10) ◽  
pp. 1093 ◽  
Author(s):  
ZHOU Wei ◽  
XIAO Peng ◽  
LI Yang ◽  
LUO Heng ◽  
HONG Wen
Keyword(s):  
Carbon Fibers ◽  
Composite Coatings ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing
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