The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 22, 1977
Filed:
Sep. 15, 1975
Robert D Shoup, Painted Post, NY (US);
William J Wein, Lowman, NY (US);
Corning Glass Works, Corning, NY (US);
Abstract
The instant invention is directed to the production of high purity fused silica bodies by means of a three-step process. In the first step, various specifically-defined ratios of aqueous alkali metal silicates with colloidal silica or quaternary ammonium silicate are gelled with certain organic reagents. In the second step, the gelled silicate mass is leached in weakly acid solutions to yield bodies of very high porosity, i.e., greater than 50%, with mean pore diameters ranging between about 400A-4000A, but wherein the pore diameters are extraordinarily uniform within a particular body. Lastly, the microporous body is fired briefly at temperatures above about 1350.degree. C. to consolidate the body to a solid transparent fused silica article having alkali metal contents less than 100 parts per million (PPM). The size of the pores, combined with the exceptional uniformity of pore sizes within an individual unit, is vital to achieve crack-free, homogeneous products.