Method to produce alumina aerogels having porosities greater than 80 percent

US6620458B2 · kind B2 · utility

Assignee

• The Regents of the University of California · US

Inventors

• John F. Poco · Livermore, US
• Lawrence W. Hrubesh · Pleasanton, US

Key dates

• Filing date: Sep 27, 2001
• Grant date: Sep 16, 2003
• Expiry date: Oct 4, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B2235/9607
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

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.