US4687750A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transparent glass-ceramics containing gahnite
Assignee: Corning Glass Works
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Filing: 1986-09-08
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Granted: 1987-08-18
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Expires: 2006-09-08
Abstract
Abstract This invention relates to the production of highly transparent glass-ceramic articles containing about 30-50% by volume gahnite having dimensions finer than about 300 Å as essentially the sole crystal phase. The articles have compositions essentially free of Li 2 O, Na 2 O, CaO, SrO, and BaO and consist essentially, by weight, of about 1.5-5% R 2 O, consisting of 0-3% K 2 O and/or 0-3% Rb 2 O and/or 0-3% Cs 2 O, 13-22% ZnO, 16-28% Al 2 O 3 , 45-65% SiO 2 , and 1.5-8% TiO 2 .
Inventors
- 👤 Linda R. Pinckney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:05
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0036
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
87 words
A highly transparent glass-ceramic article essentially free of Li 2 O, Na 2 O, CaO, SrO, and BaO, wherein gahnite having dimensions finer than about 300Åconstitutes essentially the sole crystal phase, the composition of said article consisting essentially, expressed in terms of weight percent on the oxide basis, of about 1.5-5% R 2 O, consisting of 0-3% K 2 O and/or 0-3% Rb 2 O and/or 0-3% Cs 2 O, 13-22% ZnO, 16-28% Al 2 O 3 , 45-65% SiO 2 , and 1.5-8% TiO 2 .
Claim 2
Dependent Claim
87 words
A highly transparent glass-ceramic article essentially free of Li 2 O, Na 2 O, CaO, SrO, and BaO, wherein gahnite having dimensions finer than about 300Åconstitutes essentially the sole crystal phase, the composition of said article consisting essentially, expressed in terms of weight percent on the oxide basis, of about 1.5-5% R 2 O, consisting of 0-3% K 2 O and/or 0-3% Rb 2 O and/or 0-3% Cs 2 O, 13-22% ZnO, 16-28% Al 2 O 3 , 45-65% SiO 2 , and 1.5-8% TiO 2 .
Claim 3
Dependent Claim
50 words
A glass-ceramic article according to claim 1 wherein the composition of said article contains at least 2.5% R 2 O, at least 14% ZnO, at least 18% Al 2 O 3 , less than 60% SiO 2 , at least 2.5% TiO 2 , and is essentially free from MgO.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-17 | 1991-02-16 | 1991-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-17 | 1995-02-16 | 1995-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-17 | 1999-02-16 | 1999-08-18 | $7700.00 | Window Closed / Lapsed |