US 5,547,482 A · Method of making fused silica articles

Abstract

This invention is directed to the production of essentially defect-free high purity fused silica glass articles, the method comprising the following steps: (a) forming a green body from silica particulates or a porous body of amorphous silica; (b) sintering said body in a chamber by raising the temperature of the chamber to above 1720.degree. C., while purging the chamber with helium or applying a vacuum to the chamber; and (c) consolidating the sintered body in a chamber by raising the temperature within the chamber to at least 1750.degree. C., introducing an inert gas into the chamber at a pressure less than about 6.9 MPa (1000 psig), and cooling the chamber while maintaining the pressurized atmosphere to a temperature at least below the annealing point of the glass. In the most preferred practice, a green body of silica particulates will be prepared via a sol-gel process.

Claims19

Dependent claims

A method of producing an essentially defect-free, fused silica glass article from fused silica glass particulates comprising the steps of:

(a) forming a green body from said silica glass particulates;
(b) drying and sintering said green body in a chamber by raising the temperature of the chamber to above 1720.degree. C. while purging the chamber with helium or applying a vacuum to the chamber to form a sintered body;
and
(c) consolidating said sintered body by applying pressure to said body in said chamber and raising the temperature within the chamber to at least 1750.degree. C., introducing an inert gas into the chamber at a pressure less than about 6.9 MPa, and cooling the chamber while maintaining the pressurized atmosphere to a temperature below the annealing point of said glass.

1 more element

A method of producing an essentially defect-free fused silica glass article comprising the steps of:

(a) preparing a solution which contains at least one silicon-containing organic compound having the formula Si(OR).sub.4, or SiR(OR).sub.3, where R is an alkyl group;
(b) polymerizing the silicon in the solution to form a SiO.sub.2 gel;
(c) drying the gel at a rate which causes the gel to fragment into granules having a mean particle size less than about 1 mm;
(d) sintering the granules at a temperature less than about 1150.degree. C., the density of the granules after sintering being approximately equal to their maximum theoretical density;
(e) forming a green body from the sintered granules;
(f) drying and partially sintering the green body in a chamber by raising the temperature of the chamber to above about 1000.degree. C. and thereafter subjecting the green body to one or more further step selected from the group consisting of introducing chlorine gas into the chamber, subjecting the chamber to a vacuum, and purging the chamber with an inert gas;
(g) fully sintering the green body in said chamber by raising the temperature of the chamber to above 1720.degree. C. while purging the chamber with helium or applying a vacuum to the chamber to form a fully sintered body;
and then
(h) consolidating the fully sintered body by applying pressure to the body in said chamber and raising the temperature within the chamber to at least 1750.degree. C., introducing an inert gas into the chamber at a pressure less than about 1000 psig (6.9 MPa), and thereafter cooling the chamber while maintaining the pressurized atmosphere to a temperature below the annealing point of said glass.

6 more elements

Dependencies are inferred from the claim text.

Method of making fused silica articles

Life of this patent

Method of making fused silica articles

Life of this patent

Abstract

Claims19