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Title: Process for forming transparent aerogel insulating arrays

Abstract

An improved supercritical drying process for forming transparent silica aerogel arrays is described. The process is of the type utilizing the steps of hydrolyzing and condensing aloxides to form alcogels. A subsequent step removes the alcohol to form aerogels. The improvement includes the additional step, after alcogels are formed, of substituting a solvent, such as CO/sub 2/, for the alcohol in the alcogels, the solvent having a critical temperature less than the critical temperature of the alcohol. The resulting gels are dried at a supercritical temperature for the selected solvent, such as CO/sub 2/, to thereby provide a transparent aerogel array within a substantially reduced (days-to-hours) time period. The supercritical drying occurs at about 40/sup 0/C instead of at about 270/sup 0/C. The improved process provides increased yields of large scale, structurally sound arrays. The transparent aerogel array, formed in sheets or slabs, as made in accordance with the improved process, can replace the air gap within a double glazed window, for example, to provide a substantial reduction in heat transfer. The thus formed transparent aerogel arrays may also be utilized, for example, in windows of refrigerators and ovens, or in the walls and doors thereof or as the activemore » material in detectors for analyzing high energy elementary particles or cosmic rays.« less

Inventors:
;
Publication Date:
Research Org.:
Lawrence Berkeley Lab., CA (USA)
OSTI Identifier:
5459282
Application Number:
ON: DE86013773
Assignee:
Dept. of Energy LBNL; ERA-11-005022; EDB-86-136520
DOE Contract Number:
AC03-76SF00098
Resource Type:
Patent
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; SILICA; PRODUCTION; WINDOWS; DOUBLE GLAZING; MATERIALS; ALCOHOLS; DRYING; GELS; CHALCOGENIDES; COLLOIDS; COVERINGS; DISPERSIONS; GLAZING; HYDROXY COMPOUNDS; MINERALS; OPENINGS; ORGANIC COMPOUNDS; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; SILICON COMPOUNDS; SILICON OXIDES; 360601* - Other Materials- Preparation & Manufacture; 320100 - Energy Conservation, Consumption, & Utilization- Buildings

Citation Formats

Tewari, P.H., and Hunt, A.J.. Process for forming transparent aerogel insulating arrays. United States: N. p., 1985. Web.
Tewari, P.H., & Hunt, A.J.. Process for forming transparent aerogel insulating arrays. United States.
Tewari, P.H., and Hunt, A.J.. 1985. "Process for forming transparent aerogel insulating arrays". United States. doi:.
@article{osti_5459282,
title = {Process for forming transparent aerogel insulating arrays},
author = {Tewari, P.H. and Hunt, A.J.},
abstractNote = {An improved supercritical drying process for forming transparent silica aerogel arrays is described. The process is of the type utilizing the steps of hydrolyzing and condensing aloxides to form alcogels. A subsequent step removes the alcohol to form aerogels. The improvement includes the additional step, after alcogels are formed, of substituting a solvent, such as CO/sub 2/, for the alcohol in the alcogels, the solvent having a critical temperature less than the critical temperature of the alcohol. The resulting gels are dried at a supercritical temperature for the selected solvent, such as CO/sub 2/, to thereby provide a transparent aerogel array within a substantially reduced (days-to-hours) time period. The supercritical drying occurs at about 40/sup 0/C instead of at about 270/sup 0/C. The improved process provides increased yields of large scale, structurally sound arrays. The transparent aerogel array, formed in sheets or slabs, as made in accordance with the improved process, can replace the air gap within a double glazed window, for example, to provide a substantial reduction in heat transfer. The thus formed transparent aerogel arrays may also be utilized, for example, in windows of refrigerators and ovens, or in the walls and doors thereof or as the active material in detectors for analyzing high energy elementary particles or cosmic rays.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1985,
month = 9
}
  • An improved supercritical drying process for forming transparent silica aerogel arrays is described. The process is of the type utilizing the steps of hydrolyzing and condensing aloxides to form alcogels. A subsequent step removes the alcohol to form aerogels. The improvement includes the additional step, after alcogels are formed, of substituting a solvent, such as CO.sub.2, for the alcohol in the alcogels, the solvent having a critical temperature less than the critical temperature of the alcohol. The resulting gels are dried at a supercritical temperature for the selected solvent, such as CO.sub.2, to thereby provide a transparent aerogel array withinmore » a substantially reduced (days-to-hours) time period. The supercritical drying occurs at about 40.degree. C. instead of at about 270.degree. C. The improved process provides increased yields of large scale, structurally sound arrays. The transparent aerogel array, formed in sheets or slabs, as made in accordance with the improved process, can replace the air gap within a double glazed window, for example, to provide a substantial reduction in heat transfer. The thus formed transparent aerogel arrays may also be utilized, for example, in windows of refrigerators and ovens, or in the walls and doors thereof or as the active material in detectors for analyzing high energy elementry particles or cosmic rays.« less
  • This patent describes a drying process for forming transparent aerogel insulating arrays of the type utilizing the steps of hydrolyzing and condensing alkoxides to form alcogels, and subsequently removing the alcohol therefrom to form aerogels, the improvement comprising the additional step, after alcogels are formed, of substituting a solvent having a critical temperature less than the critical temperature of the alcohol for the alcohol in the alcogels, and drying the resulting gels at a supercritical temperature for the solvent, to thereby provide a transparent aerogel array within a substantially reduced drying time period.
  • A transparent, heat-insulating coating, neutrally acting in transparency and external appearance, for transparent substrates, more particularly for insulating glass panes, is disclosed. The coating is formed from a bismuth oxide-silver-bismuth oxide multilayer system in which a more electronegative substance, i.e. a substance with a higher normal potential, is added to the bismuth oxide layers to avoid blackening under UV radiation. If manganese is used as the electronegative substance, its oxidation to higher valency states can be prevented by the addition of trivalent substances. The layers may be applied in a conventional way by diode-cathode atomization.
  • A method for preparing aerogel thin films by an ambient-pressure, continuous process is disclosed. The method of this invention obviates the use of an autoclave and is amenable to the formation of thin films by operations such as dip coating. The method is less energy intensive and less dangerous than conventional supercritical aerogel processing techniques.
  • A method for preparing aerogel thin films by an ambient-pressure, continuous process. The method of this invention obviates the use of an autoclave and is amenable to the formation of thin films by operations such as dip coating. The method is less energy intensive and less dangerous than conventional supercritical aerogel processing techniques.