US3985531A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spontaneously-formed fluormica glass-ceramics
Assignee: Corning Glass Works
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Filing: 1975-03-19
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Granted: 1976-10-12
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Expires: 1995-03-19
Abstract
Abstract This invention relates to the manufacture of articles exhibiting the physical properties and internal microstructure of glass-ceramics but which can be formed spontaneously from a glass-forming melt, i.e., the heat treatment of a glass body to cause the crystallization in situ thereof conventional in the production of glass-ceramic articles is not required. More particularly, this invention is concerned with the manufacture of glass-ceramic articles having compositions within the Na 2 O-MgO-SiO 2 -F field, wherein a fluormica constitutes the primary crystal phase, which can be formed spontaneously from a molten glass batch.
Inventors
- 👤 David G. Grossman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:22
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0009
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
140 words
A method for making a highly crystalline glass-ceramic article consisting essentially of fluormica crystals dispersed within a glassy matrix, said crystals constituting the predominant proportion of said article, which comprises the steps of: a. melting a batch for a glass consisting essentially, by weight on the oxide basis, of about 5-15% Na 2 O, 10-20% MgO, 65-75% SiO 2 , and 5-10% F; b. simultaneously cooling said melt at a rate between about 10°-1000°C./minute to a temperature about 850°-1000°C. to shape said melt into a glass body and secure phase separation and nucleation therein; c. further cooling said shaped glass body and exposing said glass body to a temperature between about 650°-850° C. for a sufficient length of time to cause crystallization of the fluormica phase in said glass body; and then d. cooling the crystallized body to room temperature.
Claim 2
Independent Claim
140 words
A method for making a highly crystalline glass-ceramic article consisting essentially of fluormica crystals dispersed within a glassy matrix, said crystals constituting the predominant proportion of said article, which comprises the steps of: a. melting a batch for a glass consisting essentially, by weight on the oxide basis, of about 5-15% Na 2 O, 10-20% MgO, 65-75% SiO 2 , and 5-10% F; b. simultaneously cooling said melt at a rate between about 10°-1000°C./minute to a temperature about 850°-1000°C. to shape said melt into a glass body and secure phase separation and nucleation therein; c. further cooling said shaped glass body and exposing said glass body to a temperature between about 650°-850° C. for a sufficient length of time to cause crystallization of the fluormica phase in said glass body; and then d. cooling the crystallized body to room temperature.
Claim 3
Dependent Claim
19 words
A method according to claim 1 wherein said time sufficient to cause crystallization is at least about two minutes.
Claim 4
Dependent Claim
27 words
A method according to claim 1 wherein said crystallized article is cooled to room temperature by means of a quick chilling technique to thermally temper said article.
References Cited (Backward Citations)
US3804608A
Cited
US3839056A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-12 | 1980-04-12 | 1980-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-12 | 1984-04-12 | 1984-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-12 | 1988-04-12 | 1988-10-12 | $7700.00 | Window Closed / Lapsed |