Method for producing metal oxide aerogels having densities less than 0.02 g/cc

US5275796A · kind A · utility

Assignee

• The Regents of the University of California · US

Inventors

• Thomas M. Tillotson · Tracy, US
• John F. Poco · Livermore, US
• Lawrence W. Hrubesh · Pleasanton, US
• Ian M. Thomas · Temperance, US

Key dates

• Filing date: Sep 5, 1991
• Grant date: Jan 4, 1994
• Expiry date: Sep 5, 2011

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/54
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A two-step method is described for making transparent aerogels which have a density of less than 0.003 g/cm.sup.3 to those with a density of more than 0.8 g/cm.sup.3, by a sol/gel process and supercritical extraction. Condensed metal oxide intermediate made with purified reagents can be diluted to produce stable aerogels with a density of less than 0.02 g/cm.sup.3. High temperature, direct supercritical extraction of the liquid phase of the gel produces hydrophobic aerogels which are stable at atmospheric moisture conditions. Monolithic, homogeneous silica aerogels with a density of less than 0.02 to higher than 0.8 g/cm.sup.3, with high thermal insulation capacity, improved mechanical strength and good optical transparency, are described.