Cristobalite reinforcement of high silica glass
US5053359A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1990 |
| Grant date | Oct 1, 1991 |
| Priority date | — |
| Expiry date | May 16, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B35/002
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A high-density silica glass article with excellent thermal shock characteristics is formed from a high purity vitreous silica containing an aluminum compound as a crystallization aid and having a dense concentration of cristobalite muclei. The aluminum compound is aluminum oxide, aluminum hydroxide, an aluminum salt, or other aluminum-oxide precursor. A refractory silica glass crucible made according to the invention has remarkable advantages in a Czochralski crystal-growing process. The entire crucible can be crystallized during the initial melt down in the Cz furnace to provide a cristobalite inner surface which effectively resists attack by the molten silicon to minimize contamination problems during crystal growing. Another embodiment of the invention relates to a unique drawn silica glass with good flexural strength having fibrous oriented veins of cristobalite embedded in a matrix of vitreous silica and having remarkable resistance to deformation at temperatures of 1500.degree. C. and higher as are encountered in certain ferrous casting and investment casting processes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.