Study on Thermal Stability of Nano-Silica Thermal Insulating Composites

2012 ◽  
Vol 488-489 ◽  
pp. 588-591
Author(s):  
Jin Peng Feng ◽  
De Ping Chen ◽  
Wen Ni ◽  
Shao Jian Ma
Keyword(s):  
Thermal Stability ◽  
Fumed Silica ◽  
High Volume ◽  
High Specific Surface Area ◽  
Volume Shrinkage ◽  
Nano Silica ◽  
Excellent Thermal Stability ◽  
Thermal Insulating ◽  
Different Temperatures ◽  
Thermal Stability Of

This work investigated the thermal stability of nano-silica thermal insulating composites, which consisted of fumed silica, fibers and opacifiers. The volume shrinkage was introduced as an evaluation index to characterize thermal stability of the composites at different temperatures. The effects of serving temperature, serving time, particle size of fumed silica and mass ratio of SiC were discussed. The results indicated nano-silica thermal insulating composites have excellent thermal stability under the temperature of 800°C. The volume shrinkage was correlated positively with serving time. High specific surface area of fumed silica could bring good thermal insulating performance, but at the same time caused high volume shrinkage when applied at high temperatures. SiC as an opacifier has little influence on volume shrinkage, but too much amount may yet increase solid heat transfer and lead to the drop of thermal insulating properties.

Effect of Fumed Titanium Oxide on Thermal Stability of Nano-Silica Thermal Insulating Composites

2011 ◽  
Vol 284-286 ◽  
pp. 102-105
Author(s):  
Jin Peng Feng ◽  
De Ping Chen ◽  
Wen Ni ◽  
Shao Jian Ma ◽  
Jin Lin Yang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Titanium Oxide ◽  
X Ray Diffraction ◽  
Nano Silica ◽  
Excellent Thermal Stability ◽  
Dry Process ◽  
Thermal Insulating ◽  
Different Temperatures ◽  
Insulating Properties ◽  
Thermal Stability Of

This work investigated the effects of fumed titanium oxide on thermal stability of nano-silica thermal insulating composites prepared by dry process. The results showed that the composites could keep excellent thermal stability at the temperatures below 800°C. However, when the samples were used at higher temperatures (>800°C), the volume shrinkage increased sharply, which directly led to a serious deformation and then affected thermal insulating properties in applications. The utilization of fumed titanium oxide could significantly improve thermal stability of the composites. When 10wt% fumed titanium oxide was added, the service temperature can increase from 800°C to 900°C. The desirable results would be achieved by adjusting the amount of additives according to practical using temperature. In addition, field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were employed to characterize the microstructure and phase transformations of the composites treated at different temperatures.

Study of thermal stability of fumed silica based thermal insulating composites at high temperatures

2011 ◽  
Vol 42 (7) ◽  
pp. 1821-1825 ◽  
Author(s):  
Jinpeng Feng ◽  
Yongye Yan ◽  
Deping Chen ◽  
Wen Ni ◽  
Jinlin Yang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Temperatures ◽  
Fumed Silica ◽  
Thermal Insulating ◽  
Thermal Stability Of

Microstructure studies of tungsten silicide schottky contacts on Gaas

1987 ◽  
Vol 45 ◽  
pp. 328-329
Author(s):  
Yih-Cheng Shih ◽  
E. L. Wilkie
Keyword(s):  
Thermal Stability ◽  
Field Effect Transistors ◽  
Schottky Contact ◽  
Schottky Contacts ◽  
Excellent Thermal Stability ◽  
Barrier Heights ◽  
Gaas Substrates ◽  
Film Adhesion ◽  
Threshold Voltages ◽  
Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

STRUCTURE AND THERMAL STABILITY OF THE SULFIDE OVERLAYERS ON CH3CSNH2-PASSIVATED GaAs(100) SURFACES

2001 ◽  
Vol 08 (01n02) ◽  
pp. 19-23 ◽  
Author(s):  
F. Q. XU ◽  
E. D. LU ◽  
H. B. PAN ◽  
C. K. XIE ◽  
P. S. XU ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Electron Spectroscopy ◽  
Photoemission Spectroscopy ◽  
Low Energy Electron Diffraction ◽  
Native Oxides ◽  
Sulfur Passivation ◽  
Different Temperatures ◽  
Low Energy Electron ◽  
Synchrotron Radiation Photoemission ◽  
Thermal Stability Of

Chemically sulfur passivation of GaAs(100) by thioacetamide ( CH 3 CSNH 2) has been studied using synchrotron radiation photoemission spectroscopy (SRPES), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED). The measurement of SRPES and AES showed that the top layer of native oxides over GaAs(100) was removed and the sulfides of Ga and As were formed after the passivation process. The thermal stability and surface structure have also been studied by annealing the passivated samples at different temperatures. We found that the surface sulfides could be removed gradually; as a result, a clean, ordered and thus Fermi level unpinning surface was finally achieved. The surface restructures with GaAs(100)–S(2×1) and 4×1 LEED patterns were observed on annealing above 260°C and at 550°C respectively.

scholarly journals Improved thermal stability of SiCf/SiC ceramic matrix composites fabricated by PIP process

2021 ◽  
Vol 15 (2) ◽  
pp. 164-169
Author(s):  
Jian Gu ◽  
Sea-Hoon Lee ◽  
Daejong Kim ◽  
Hee-Soo Lee ◽  
Jun-Seop Kim
Keyword(s):  
Thermal Stability ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Sic Fiber ◽  
Sic Ceramic ◽  
Different Temperatures ◽  
Pre Treatment ◽  
Thermal Deterioration ◽  
Thermal Stability Of

Improvement of the thermal stability of continuous SiC fiber reinforced SiC ceramic matrix composites (SiCf/SiC CMC) by the pre-treatment of SiC fillers and the suppression of oxidation during polymer impregnation and pyrolysis (PIP) process were investigated. Dense SiCf/SiC CMCs were fabricated using the slurry infiltration and PIP process under a purified argon atmosphere. Structure and mechanical properties of the SiCf/SiC CMC heated at different temperatures were evaluated. The flexural strength of the SiCf/SiC CMC decreased only 15.3%after heating at 1400 ?C, which exhibited a clear improvement compared with the literature data (49.5% loss), where severe thermal deterioration of SiCf/SiC composite occurred at high temperatures by the crystallization and decomposition of the precursor-derived ceramic matrix. The thermal stability of the SiCf/SiC CMC fabricated by PIP process was improved by the pre-treatment of SiC fillers for removing oxides and the strict atmosphere control to prevent oxidation.

Thermal Stability of Solid Aluminum Electrolytic Capacitors with Conductive Polyaniline Counter Electrode

2012 ◽  
Vol 512-515 ◽  
pp. 1018-1021
Author(s):  
Xu Fei Zhu ◽  
Long Fei Jiang ◽  
Wei Xing Qi ◽  
Chao Lu ◽  
Ye Song
Keyword(s):  
Thermal Stability ◽  
Counter Electrode ◽  
Electrolytic Capacitor ◽  
Aluminum Electrolytic Capacitor ◽  
Dodecylbenzenesulfonic Acid ◽  
Excellent Thermal Stability ◽  
High Frequencies ◽  
Solid Aluminum ◽  
Good Thermal Stability ◽  
Thermal Stability Of

To overcome the risk of electrolyte leakage and the shortcoming of higher impedance at high frequencies for the conventional aluminum electrolytic capacitor impregnated with electrolyte solutions, solid aluminum electrolytic capacitor employing conducting polyaniline (PANI) as a counter electrode was developed. The as-fabricated solid capacitors have very low impedances at high frequencies and excellent thermal stability. The superior performances can be ascribed to high conductivity and good thermal stability of the camphorsulfonic acid (CSA)-dodecylbenzenesulfonic acid (DBSA) co-doped PANI.

Thermal Stability of Mechanical Properties of Copper after Equal-Channel Angular Pressing

2008 ◽  
Vol 584-586 ◽  
pp. 960-965 ◽  
Author(s):  
Tamara Kravchenko ◽  
Alexander Korshunov ◽  
Natalia Zhdanova ◽  
Lev Polyakov ◽  
Irina Kaganova
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Chemical Composition ◽  
Yield Strength ◽  
Equal Channel Angular Pressing ◽  
Angular Pressing ◽  
Different Temperatures ◽  
Thermal Stability Of

Annealed oxygen-free and tough-pitch copper samples have been processed by equalchannel angular pressing (ECAP) by route BC. The samples included 8 x 8 mm section pieces and a 40 mm diameter bar. Thermal stability was assessed based on the changes in the standard mechanical properties (conventional yield strength, tensile strength, elongation, proportional elongation and contraction) after annealing at different temperatures for 1 hour. Thermal stability of the same grade of material has been found to be different for different batches and to depend on the structural conditions of deformed material. The zone of thermal stability for copper of the two grades of interest does not depend on the material’s chemical composition.

Thermal stability of WAlN/WAlON/Al2O3-based solar selective absorber coating

MRS Advances ◽  
2016 ◽  
Vol 1 (41) ◽  
pp. 2807-2813 ◽  
Author(s):  
Atasi Dan ◽  
Kamanio Chattopadhyay ◽  
Harish C. Barshilia ◽  
Bikramjit Basu
Keyword(s):  
Thermal Stability ◽  
Stainless Steel ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Rf Magnetron Sputtering ◽  
Thermal Conversion ◽  
Solar Absorptance ◽  
Excellent Thermal Stability ◽  
Oxidation In Air ◽  
Thermal Stability Of

AbstractThe solar absorptance property of W/WAlN/WAlON/Al2O3-based coatings, deposited by DC/RF magnetron sputtering on stainless steel substrate was studied by measuring the reflectance spectra in the wavelength range of 250 - 2500 nm. The effect of thermal annealing on the optical properties of the solar selective absorber coatings was investigated. Annealing the coatings at 450°C for 150 hrs in air did not show any significant change in the spectral properties of the absorber coating indicating the excellent thermal stability of the coating. The W layer acts as infrared reflective layer and diffusion barrier on stainless steel substrate. The top Al2O3 layer serves as dense shield to protect the under layers from oxidation in air. In summary, the present study indicates the potential application of W/WAlN/WAlON/Al2O3-based selective coatings in high temperature photo thermal conversion systems.

Effect of Fumed Silica and Zinc Borate on the Thermogravimetric Analysis Curves of ABS/Magnesium Hydroxide Composite

2014 ◽  
Vol 599-601 ◽  
pp. 183-186
Author(s):  
Zhang Ting Li ◽  
Yue Qun Lu ◽  
Li Li Fan ◽  
Pei Bang Dai ◽  
Xia Su ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Thermal Stability ◽  
Flame Retardant ◽  
Fumed Silica ◽  
Acrylonitrile Butadiene Styrene ◽  
Zinc Borate ◽  
Processing Temperature ◽  
Great Decrease ◽  
Thermal Stability Of ◽  
Butadiene Styrene

For achieving sufficient flame retardancy, high magnesim hydroxide (MH) content is needed in MH flame retardant Acrylonitrile-butadiene-styrene copolymer (ABS) composites (ABS/MH), which will cause a great decrease in mechanical property and difficulty in preparing samples for measurement. We prepared ABS/MH filled high 60.0% flame retardant by compounding ABS and modified flame retardant MH, fumed silica (SiO2) and zinc borate (ZB) via TX-10 phosphate/polyacrylate latex and studied the effect of a small amount of SiO2 and ZB with MH in ABS for improving the thermal decomposition of ABS/MH. The thermal stability of the modified flame retardant could meet the processing temperature of ABS. The incorporation of ZB, SiO2 or SiO2/ZB could improve the thermal stability of ABS/MH.

Sign in / Sign up

Export Citation Format

Share Document