Research & Development

Study on stability of silica aerogel after heat treatment

  • Rui Gao ,
  • Zhangjian Zhou ,
  • Hongbo Zhang ,
  • Xiaoge Zhang
Expand
  • 1. College of Materials Science and Engineering,University of Science and Technology Beijing;Beijing 100083 China
    2. Zhonghai Runda Investment Co.

Received date: 2019-03-26

  Online published: 2020-06-10

Abstract

Silica aerogel has a broad application prospect in the field of thermal insulation due to its very high porosity and very low thermal conductivity.Tthe change of thermal conductivity of silica aerogel under different temperature heat treatment conditions was studied,and the related mechanism was explained on the basis of microstructure evolution.With the increase of heat treatment temperature,the thermal conductivity of aerogels first decreases and then rises.When the heat treatment temperature was lower than 400 ℃,the thermal conductivity of the aerogel decreased as the heat treatment temperature increase.This is because the lower temperature heat treatment removes most of the impurities inside the aerogel and makes the internal pore structure more uniform.When the heat treatment temperature was at 400~700 ℃,the higher temperature made the pore diameter inside increase significantly,and the aerogel particles increase,so that the thermal conductivity increased with the heat treatment temperature increase.When the heat treatment temperature was higher than 700 ℃,the aerogel particles began to sinter,the skeleton structure collapsed,the density increased remarkably,and the thermal conductivity also rised sharply.At this time,the typical characteristics of aerogel lightweight porous were not available.It is considered to have expired.Results showed that some guidance for the application of hydrophilic aerogel:the aerogel will have a best thermal insulation performance when treatment at 400 ℃ for a period of time.The aerogel′s working temperature should be below 700 ℃,and increase of temperature will slightly decrease the thermal insulation capacity of the aerogel;The aerogel will lose its thermal insulation capacity at temperatures above 700 ℃,so it should not be used at this temperature.

Cite this article

Rui Gao , Zhangjian Zhou , Hongbo Zhang , Xiaoge Zhang . Study on stability of silica aerogel after heat treatment[J]. Inorganic Chemicals Industry, 2019 , 51(9) : 50 -53 . DOI: 10.11962/1006-4990.2018-0567

References

[1] Akimov Y K . Fields of application of aerogels(review)[J]. Instruments and Experimental Techniques, 2003,46(3):287-299.
[2] Jones S M . Aerogel:space exploration applications[J]. Journal of Sol-Gel Science and Technology, 2006,40(2):351-357.
[3] Fricke J, Emmerling A . Aerogels preparation,properties,applications[J]. Structure and Bonding, 1992,77:37-87.
[4] 魏鹏湾, 闫共芹, 赵冠林 , 等. 二氧化硅气凝胶复合隔热材料研究进展[J]. 无机盐工业, 2016,48(10):1-6.
[5] Riffat S B, Qiu G Q . A review of state of the art aerogel applications in buildings[J]. International Journal of Low-Carbon Technologies, 2013,8(1):1-6.
[6] Cuce E, Cuce P M, Wood C J , et al. Toward aerogel based thermal superinsulation in buildings:a comprehensive review[J]. Renewable & Sustainable Energy Reviews, 2014,34:273-299.
[7] Torgal F P . Introduction to nano and biotech based materials for energy building efficiency[M] ∥Nano and Biotech Based Materials for Energy Building Efficiency.Springer,Cham, 2016: 1-16.
[8] Cho M H, Hong S C . A study on insulation fire proof materials using silica aerogels[J]. Journal of the Korea Academia-Industrial Cooperation Society, 2015,16(10):6816-6822.
[9] de la Rosa-Fox N .Aggregation process in silica aerogels on sintering[J].Journal of Non-Crystalline Solids, 1995, 192-193:534-538.
[10] Yang G X, Biswas P . Computer simulation of the aggregation and sintering restructuring of fractal-like clusters containing limited numbers of primary particles[J]. Journal of Colloid and Interface Science, 1999,211(1):142-150.
[11] Sarawade P B, Kim J K, Hilonga A , et al. Synjournal of sodium sili-cate-based hydrophilic silica aerogel beads with superior proper-ties:Effect of heat-treatment[J]. Journal of Non-Crystalline Solids, 2011,357(10):2156-2162.
[12] Huang D, Guo C, Zhang M , et al. Characteristics of nanoporous silica aerogel under high temperature from 950 ℃ to 1 200 ℃[J]. Materials & Design, 2017,129:82-90.
[13] Wei G, Wang L, Xu C , et al. Thermal conductivity investigations of granular and powdered silica aerogels at different temperatures and pressures[J]. Energy and Buildings, 2016,118:226-231.
[14] Schwertfeger F, Frank D, Schmidt M . Hydrophobic waterglass based aerogels without solvent exchange or supercritical drying[J]. Journal of Non-Crystalline Solids, 1998,225:24-29.
[15] Schmidt M, Schwertfeger F . Applications for silica aerogel products[J]. Journal of Non-Crystalline Solids, 1998,225:364-368.
[16] Kim G S, Hyun S H . Effect of mixing on thermal and mechanical properties of aerogel-PVB composites[J]. Journal of Materials Science, 2003,38(9):1961-1966.
[17] Rao A P, Pajonk G M, Rao A V . Effect of preparation conditions on the physical and hydrophobic properties of two step processed ambient pressure dried silica aerogels[J]. Journal of Materials Sci ence, 2005,40(13):3481-3489.
[18] Rao A V, Rao A P, Kulkarni M M . Influence of gel aging and Na2SiO3 / H2O molar ratio on monolithicity and physical properties of water-glass-based aerogels dried at atmospheric pressure[J]. Journal of Non-Crystalline Solids, 2004,350:224-229.
[19] Zhuravlev L T . The surface chemistry of amorphous silica.Zhuravlev model[J]. Colloids and Surfaces A:Physicochemical and Engineer ing Aspects, 2000,173(1/2/3):1-38.
[20] Kuchta L . About the synjournal and thermal stability of SiO2-aerogel[J]. Journal of Thermal Analysis, 1996,46(2):515-520.
[21] Olivi-Tran N, Jullien R . Numerical simulations of sintering,application to partially densified aerogels[J]. Journal of Sol-Gel Science and Technology, 1997,8(1/2/3):813-817.
[22] Phalippou J . Comparison between sintered and compressed aero gels[J]. Optical Materials, 2004,26(2):167-172.
Outlines

/