High purity opaque silica glass
US5977000A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1997 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Nov 25, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249969
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Opaque silica glass having a density of 2.0 to 2.18 g/cm.sup.3, sodium and potassium elements concentrations in the silica glass of each 0.5 ppm or less and an OH group concentration of 30 ppm or less, and containing bubbles which are independent bubbles having the following physical values: a bubble diameter of 300 .mu.m or less, and a bubble density of 100,000 to 1,000,000 bubbles/cm.sup.3, and a production process for opaque silica glass, including: filling quartz raw material grain having a particle size of 10 to 350 .mu.m in a heat resistant mold, heating it in a non-oxidizing atmosphere from a room temperature up to a temperature lower by 50 to 150.degree. C. than a temperature at which the above raw material grain is melted at a temperature-raising speed not exceeding 50.degree. C./minute, then, slowly heating it up to a temperature higher by 10 to 80.degree. C. than the temperature at which the quartz raw material grain is melted at the speed of 10.degree. C./minute or less, and cooling after maintaining at the above temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.