US3445252A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alpha- and beta-cristobalite glassceramic articles and methods
Assignee: Corning Glass Works
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Filing: 1966-09-14
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Granted: 1969-05-20
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Expires: 1986-09-14
Abstract
No abstract record available.
Inventors
- 👤 John F Macdowell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:34
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0018; C03C10/0027; C03C10/0036
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
112 words
A METHOD FOR MAKING A GLASS-CERAMIC BODY CONTAINING A DERIVATIVE OF ALPHA-CRISTOBALITE AS THE PRINCIPAL CRYSTAL FORM COMPRISING THE STEPS OF: (A) MELTING A GLASS-FORMING COMPOSITION CONSISTING ESSENTIALLY, BY WEIGHT ON THE OXIDE BASIS, OF 5-40% AL2O3, 55-90% SIO2, AND THE BALANCE 0.5-3% LI2O; (B) SIMULTANEOUSLY COOLING THE MELT BELOW THE TRANSFORMATION RANGE OF SAID MELT AND FORMING A GLASS SHAPE THEREFROM; (C) HEATING SAID GLASS SHAPE TO ABOUT 850*-950*C. FOR AT LEAST ABOUT 1/4 HOUR TO ATTAIN THE DESIRED NUCLEATION; (D) RAISING THE TEMPERATURE OF SAID GLASS SHAPE TO ABOUT 1000*-1400*C. FOR A PERIOD OF TIME SUFFICIENT TO ATTAIN THE DESIRED CRYSTALLIZATION; AND (E) COOLING SAID GLASS SHAPE TO ROOM TEMPERATURE.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-05-19 | 1972-11-18 | 1973-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-05-19 | 1976-11-18 | 1977-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-05-19 | 1980-11-18 | 1981-05-20 | $7700.00 | Window Closed / Lapsed |