Title: Method to produce alumina aerogels having porosities greater than 80 percent

Abstract

A two-step method for producing monolithic alumina aerogels having porosities of greater than 80 percent. Very strong, very low density alumina aerogel monoliths are prepared using the two-step sol-gel process. The method of preparing pure alumina aerogel modifies the prior known sol method by combining the use of substoichiometric water for hydrolysis, the use of acetic acid to control hydrolysis/condensation, and high temperature supercritical drying, all of which contribute to the formation of a polycrystalline aerogel microstructure. This structure provides exceptional mechanical properties of the alumina aerogel, as well as enhanced thermal resistance and high temperature stability.

Inventors:

Poco, John F.; Hrubesh, Lawrence W.

Issue Date:

Tue Sep 16 00:00:00 EDT 2003

Research Org.:

Univ. of California, Oakland, CA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1174490

Patent Number(s):

6620458

Application Number:

09/970,251

Assignee:

The Regents of the University of California (Oakland, CA)

Patent Classifications (CPCs):

C - CHEMISTRY C01 - INORGANIC CHEMISTRY C01F - COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS

C - CHEMISTRY C01 - INORGANIC CHEMISTRY C01P - INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

Show more

C - CHEMISTRY C01 - INORGANIC CHEMISTRY C01F - COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS

C01F7/448 - {using superatmospheric pressure, e.g. hydrothermal conversion of gibbsite into boehmite}

C - CHEMISTRY C01 - INORGANIC CHEMISTRY C01P - INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

C01P2006/10 - Solid density
C01P2006/14 - Pore volume
C01P2006/32 - Thermal properties

C - CHEMISTRY C04 - CEMENTS C04B - LIME, MAGNESIA

C04B14/302 - {Aerogels}
C04B2111/00982 - {as construction elements for space vehicles or aeroplanes}
C04B2235/3217 - Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
C04B2235/441 - Alkoxides, e.g. methoxide, tert-butoxide
C04B2235/5409 - expressed by specific surface values
C04B2235/77 - Density
C04B2235/96 - Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
C04B2235/9607 - Thermal properties, e.g. thermal expansion coefficient
C04B35/10 - based on aluminium oxide
C04B35/111 - Fine ceramics
C04B35/624 - Sol-gel processing
C04B35/6264 - {Mixing media, e.g. organic solvents}
C04B35/62655 - {Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying}
C04B38/0045 - {by a process involving the formation of a sol or a gel, e.g. sol-gel or precipitation processes}

Show less

DOE Contract Number:  

W-7405-ENG-48

Resource Type:

Patent

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE