Transparent and nonexpansive glass-ceramic
US5017519A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1990 |
| Grant date | May 21, 1991 |
| Priority date | — |
| Expiry date | Apr 23, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C10/0045
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A transparent and colorless glass-ceramic containing crystals of .beta.-quartz and .beta.-eucryptite is obtained by heat-treating a glass essentially composed of 63-69 wt % of SiO.sub.2, 18-22 wt % of Al.sub.2 O.sub.3, 3-5 wt % of Li.sub.2 O, 1-3 wt % of MgO, 4-6 wt % of ZrO.sub.2, 0-2 wt % of ZnO, 0-2 wt % of P.sub.2 O.sub.5, 0-2 wt % of Na.sub.2 O, 0-2 wt % of BaO and 0.3-1 wt % of As.sub.2 O.sub.3, with proviso that the proportion of ZrO.sub.2 to SiO.sub.2 is not lower than a specified level and that the molar ratio of Al.sub.2 O.sub.3 to the total of Li.sub.2 O, MgO and ZnO is within a specified range. The thermal expansion coefficient of this glass-ceramic is very close to zero over the range from room temperature to about 300.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.