Improvement in the high temperature thermal insulation performance of Y2O3 opacified silica aerogels

In automotive technology, the proper use of thermal insulation materials helps improve the performance and life of internal equipment and reduce maintenance cost. In this study, plasma spraying and flame spraying are used to prepare and coat a new MgO-B2O3-SiO2-Zn powder on the SUS304 substrate. The resulting coating as thermal insulation layer formed a networked microstructure between the substrates to improve the thermal insulation performance of the material. By validation of thermal radiation experiments, the thermal insulation effects of various ceramic powders were compared, the high-temperature and low-temperature thermal insulation materials for about 300 and 100 °C were determined, and the thermal insulation performance of the constructed material coatings was verified by analysis.

Download Full-text

Alumina-Doped Silica Aerogels for High-Temperature Thermal Insulation

Gels ◽

10.3390/gels7030122 ◽

2021 ◽

Vol 7 (3) ◽

pp. 122

Author(s):

Yu Wu ◽

Xiaodong Wang ◽

Lin Liu ◽

Ze Zhang ◽

Jun Shen

Keyword(s):

Heat Treatment ◽

High Temperature ◽

Thermal Insulation ◽

Large Scale ◽

Low Cost ◽

Linear Shrinkage ◽

Silica Aerogels ◽

Hydroxyl Groups ◽

Scale Production ◽

Α Al2o3

In this study, we used two methods to prepare alumina-doped silica aerogels with the aim of increasing the thermal stability of silica aerogels. The first method was physical doping of α-Al2O3 nano powders, and the second method was to create a chemical compound via the co-precursor of TEOS and AlCl3·6H2O in different proportions. The shrinkage, chemical composition, and specific surface area (SSA) of samples after heating at different temperatures were analyzed. Our results show that the silicon hydroxyl groups of samples derived from AlCl3·6H2O gradually decreased and nearly disappeared after heating at 800 °C, which indicates the complete dehydration of the silicon hydroxyl. Thus, the samples exhibited a large linear shrinkage and decreased SSA after high-temperature heat treatment. By contrast, samples doped with α-Al2O3 powders retained abundant silicon hydroxyl groups, and the 6.1 wt.% α-Al2O3-doped sample exhibited the lowest linear shrinkage of 11% and the highest SSA of 1056 m2/g after heat treatment at 800 °C. The alumina-doped silica aerogels prepared using a simple and low-price synthesized method pave the way for the low-cost and large-scale production of high-temperature thermal insulation.

Download Full-text

The Insulated Effect of New Inorganic Coatings on the Surface of Fiber Paper

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.373-374.682 ◽

2008 ◽

Vol 373-374 ◽

pp. 682-685

Author(s):

Fei He ◽

Xiao Dong He ◽

J.F. Li ◽

Ming Wei Li ◽

S.M. Zhang

Keyword(s):

High Temperature ◽

Thermal Insulation ◽

Random Network ◽

Inorganic Coatings ◽

Insulation Effect ◽

Service Conditions ◽

Fiber Materials ◽

Insulation Performance ◽

Continuous Random Network ◽

Made In

The unitary thermal insulation fiber materials can not satisfy rigorous high temperature environment usually. New inorganic coatings were prepared by adding SiO2 aerogels super-insulation powder into high temperature adhesive. Aerogels are high dispersive solid materials which consist of colloid particles or high polymer molecule and have continuous random network structure filling with gaseous dispersive medium. The coatings with super insulation function were made by means of adding thermal-proof materials to the coatings. The microstructure of light porous power and the states of coatings on the surface of fiber paper under different state were observed by scanning electron microscope (SEM). The insulated effect of the composite materials was tested by considering thermal conductivity. On the basis of this, the coatings on the surface of fiber paper were optimized according to the material thermal-insulation performance and the materials that could be satisfactory to the service conditions were made in the end. The results show that silica aerogels powder is dispersed equably in high temperature adhesive. The new inorganic coatings possess themselves of good thermal-insulation effect and can be used as insulated space-layers. The insulation ability of fiber paper is improved obviously.

Download Full-text