Low expansion transparent crystallized glass-ceramic
US5336643A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 18, 1993 |
| Grant date | Aug 9, 1994 |
| Priority date | — |
| Expiry date | Mar 18, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C10/0045
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A low expansion crystallized glass-ceramic which has a coefficient of thermal expansion (.alpha..times.10.sup.-7 /.degree. C.) within the range of from -10 to +10, has a remarkably reduced variation in the coefficient of thermal expansion accompanied by variation in heat treatment conditions, has an excellent optical homogeniety owing to reduced melting temperature in the base glass and has an improved transparency is obtained by restricting the ratio in weight of Al.sub.2 O.sub.3 to (SiO.sub.2 +P.sub.2 O.sub.5) within the range of 0.38 and 0.50 and adding MgO, BaO and ZnO of specific content ranges as essential ingredients in a base glass of a SiO.sub.2 -Al.sub.2 O.sub.3 -Li.sub.2 O system containing P.sub.2 O.sub.5 as an optional ingredient and TiO.sub.2 and ZrO.sub.2 as nucleating agents.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.