US3985534A
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 The instant invention involves the production of articles exhibiting an internal microstructure and physical characteristics like those of glass-ceramic bodies but which can be formed spontaneously from a molten glass. Hence, in contrast to the production of conventional glass-ceramic articles, no heat treatment of a parent or precursor glass body is required to cause crystallization in situ to occur. More particularly, the instant invention is concerned with the manufacture of highly crystalline glass-ceramic articles, having compositions within the Li 2 O-Na 2 O-Al 2 O 3 -MgO-SiO 2 -F system, wherein a fluormica constitutes the predominant crystal phase, which can be formed spontaneously from a molten glass batch.
Inventors
- 👤 James E. Flannery
- 👤 Dale R. Wexell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:53
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/16; C03C10/0018; C03C10/0027
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
170 words
A method for making a highly crystalline glass-ceramic article consisting essentially of fluormica crystals dispersed within a glassy matrix, said crystals constituting at least 50% by volume of said article, which comprises the steps of: a. melting a batch for a glass consisting essentially, by weight on the oxide basis as calculated from the batch, of about 1-5% Li 2 O, 3-6% Na 2 O, 2-6% Al 2 O 3 , 45-75% SiO 2 , 3-7% F, and 5-10% B 2 O 3 and/or 1.5-4.5% MoO 3 and/or WO 3 ; b. simultaneously cooling said melt at a rate between about 10°-1000° C./minute to a temperature about 875°-1050° C. to shape said melt into a glass body and obtain phase separation and nucleation therein; c. further cooling said shaped glass body and exposing said glass body to a temperature between about 750°-950° C. for a sufficient length of time to cause crystallization of the fluormica crystals in said glass body; and then d. cooling the crystallized body to room temperature.
Claim 2
Independent Claim
170 words
A method for making a highly crystalline glass-ceramic article consisting essentially of fluormica crystals dispersed within a glassy matrix, said crystals constituting at least 50% by volume of said article, which comprises the steps of: a. melting a batch for a glass consisting essentially, by weight on the oxide basis as calculated from the batch, of about 1-5% Li 2 O, 3-6% Na 2 O, 2-6% Al 2 O 3 , 45-75% SiO 2 , 3-7% F, and 5-10% B 2 O 3 and/or 1.5-4.5% MoO 3 and/or WO 3 ; b. simultaneously cooling said melt at a rate between about 10°-1000° C./minute to a temperature about 875°-1050° C. to shape said melt into a glass body and obtain phase separation and nucleation therein; c. further cooling said shaped glass body and exposing said glass body to a temperature between about 750°-950° C. for a sufficient length of time to cause crystallization of the fluormica crystals 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 2 minutes.
Claim 4
Dependent Claim
27 words
A method according to claim 1 wherein said crystallized body is cooled to room temperature by means of a quick chilling technique to thermally temper said body.
References Cited (Backward Citations)
US3667973A
Cited
US3804608A
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 |