US 4,789,389 A · Method for producing ultra-high purity, optical quality, glass articles

Abstract

A method for producing ultra-high purity, optical quality, glass articles is disclosed which involves: (1) forming a gel from a silicon-containing organic compound, such as, TEOS; (2) drying the gel to produce granules having a mean particle size of less than about 1 millimeter; (3) fully sintering the granules to produce high purity, artificial sand; (4) casting the artificial sand by conventional techniques, such as, slip casting, to form a high density, porous, green body; (5) drying and partially sintering the green body; (6) fully sintering the green body under vacuum; and (7) hot isostatic pressing ("hipping") the green body. The glass articles produced by the process have higher purity, greater homogeneity, and less IR absorption than existing, commercially available, premium quality, fused silica, glass articles. In addition, in accordance with the invention, high purity glass articles of complex shapes can be directly cast, rather than being machined or pressed from sheets of glass, as in the prior art.

Claims33

Dependent claims

A method for producing a 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 one millimeter;
(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 (i) raising the temperature of the chamber to above about 1000.degree. C., and (ii) introducing chlorine gas into the chamber and/or subjecting the chamber to a vacuum and/or purging the chamber with an inert gas;
and
(g) fully sintering the green body in a chamber by raising the temperature of the chamber to a temperature above about 1720.degree. C. while purging the chamber with helium or applying a vacuum to the chamber.

5 more elements

Dependencies are inferred from the claim text.

Method for producing ultra-high purity, optical quality, glass articles

Life of this patent

Method for producing ultra-high purity, optical quality, glass articles

Life of this patent

Abstract

Claims33