Aluminum Silicate Aerogels with High Temperature Stability

Trifu, Roxana; Rhine, Wendell E.; Mel'nikova, I. G.; White, Shannon; Hurwitz, Frances I.

doi:10.1002/9780470584354.ch28

Cited by 4 publications

(3 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Irrespective of the slight increment of thermal conductivity of TPS composites as a function of temperature, the mullite formation at elevated temperatures as evidenced from XRD studies keep the thermal insulation performance of TPS intact. This is in contrast to silica and alumina aerogels which suffer from loss in thermal insulation performance, especially after heat treatment at 700°C in air …”

Section: Resultssupporting

confidence: 88%

Development and characterization of a contoured passive thermal protection system

Daniel

Srikanth

Kumar

et al. 2018

Int J Applied Ceramic Tech

View full text Add to dashboard Cite

Present work deals with process refinement, fabrication, and testing of a novel contoured passive thermal protection system (TPS), based on aluminosilicate fiber reinforced silica matrix composite. Taguchi method‐based statistical approach was employed to understand the effect of process parameters such as thickness, layer density, stacking sequence and firing temperature on dielectric properties, flexural strength, and bulk density of composites. Analysis of variance was performed to ensure the statistical significance. The developed TPS was characterized for thermal insulation properties by testing under infrared heating conditions. The science behind the insulation characteristics of the TPS was analyzed using FTIR, XRD, and SEM to understand the associated high‐temperature phase transitions. Present study has shown that, the back‐face temperature exponentially decays with TPS thickness. For TPS having 9 mm thickness, the back‐face temperature was found to be below 100°C when the front face was exposed to 1000°C. The insulation index was found to be increasing with increase in temperature and TPS thickness. Improved thermal insulation characteristics of TPS are due to energy consuming processes such as crystalline changes and micro cracks formation.

show abstract

Section: Resultssupporting

confidence: 88%

Development and characterization of a contoured passive thermal protection system

Daniel

Srikanth

Kumar

et al. 2018

Int J Applied Ceramic Tech

View full text Add to dashboard Cite

show abstract

“…For instance, alumina aerogels have attracted vast attention for their ability to maintain the large surface area and mesopore structure up to 1000 • C. [7][8][9] Alumina aerogels can be synthesized by using aluminum alkoxides or inorganic aluminum salts as precursors. 8,[10][11][12][13] The aluminum alkoxides such as aluminum tri-sec-butoxide and aluminum isopropoxide are typical sources for fabricating monolithic alumina aerogels. Nevertheless, the extremely high sensitivity of aluminum alkoxides to water usually makes it difficult to control the preparation process, 8,14 and the aluminum alkoxides are expensive.…”

Section: Introductionmentioning

confidence: 99%

Foreign element doping and thermal stability of alumina aerogels

Peng

Feng

et al. 2021

J Am Ceram Soc.

View full text Add to dashboard Cite

The addition of foreign elements is considered as an effective method to improve the thermal stability of alumina aerogels at a higher temperature. However, the location and stabilizing mechanism of the foreign elements in the alumina aerogel have not been carefully studied. In this work, Si or La was introduced into the network of alumina aerogels through a sol-gel strategy. The Si-doped alumina aerogel maintained high surface area (92 m 2 /g) and pore volume (0.572 cm 3 /g) even at 1300 • C. The dopants prevented α-Al 2 O 3 transformation at elevated temperatures (1200 • C-1300 • C). The distribution of foreign ions and their stabilizing mechanism were discussed in detail. The doped alumina aerogels reinforced by mullite fiber felt, with quite low density and thermal conductivity, can be used as high-temperature thermal insulations.

show abstract

“…Fibre reinforced silica aerogel composite, with low thermal conductivity and high mechanical performance, expands its uses especially as an excellent thermal insulation material [1][2][3][4][5][6][7][8][9][10][11]. However, alumina-silica (Al 2 O 3 −SiO 2 ) aerogel, with high specific surface area, high porosity and high temperature stability [12][13][14][15][16][17], is attracting more increased interest in the field of thermal insulation application [18][19][20][21][22][23][24][25] at elevated temperature. As with SiO 2 aerogel, the Al 2 O 3 −SiO 2 aerogel is fragile and difficult to use directly.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of fibre reinforced Al2O3−SiO2 aerogel composite with high density uniformity via a facile high-pressure impregnation approach

Yang

Jiang

Feng

et al. 2017

PAC

View full text Add to dashboard Cite

Alumina-silica (Al 2 O 3 −SiO 2) aerogel composite, with low density, low thermal conductivity and hightemperature stability, is attracting increased interest in the field of thermal insulation application. In this paper, a novel way to fabricate fibre reinforced Al 2 O 3 −SiO 2 aerogel composite via a facile high-pressure impregnation approach was reported. Two Al 2 O 3 −SiO 2 aerogel composites, HPe and LPe, were synthesized via high-pressure and low-pressure impregnation approach, respectively. The effects of the impregnation approach on the aerogel composites performance were studied, and the impregnation model was established. The results showed that the as-prepared HPe exhibited higher density uniformity, better high-temperature stability, higher specific surface area and lower thermal conductivity. It was also shown that the effect of impregnation approach on the mean density and morphology of the aerogel composites is negligible. However, the standard deviation of density (0.00857) and mean thickness shrinkage (9.98%) of HPe were 37.8% and 15.4% lower than that of LPe, respectively. The specific surface area (884.1 m 2 /g) of HPe was 43.5% higher than that of LPe. The thermal conductivity of HPe at 1100°C was 2.74% lower than that of LPe. The impregnation model of the aerogel composites presented that the density uniformity and thermal conductivity of HPe were improved obviously, because there were less large pores in HPe than in the LPe.

show abstract

Aluminum Silicate Aerogels with High Temperature Stability

Cited by 4 publications

References 17 publications

Development and characterization of a contoured passive thermal protection system

Development and characterization of a contoured passive thermal protection system

Foreign element doping and thermal stability of alumina aerogels

Synthesis of fibre reinforced Al2O3−SiO2 aerogel composite with high density uniformity via a facile high-pressure impregnation approach

Contact Info

Product

Resources

About