Low temperature production of high purity fused silica
US4059658A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1975 |
| Grant date | Nov 22, 1977 |
| Priority date | — |
| Expiry date | Sep 15, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S65/901
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.