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US3985532A
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US
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Spontaneously-formed celsian 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 relates to the production of articles exhibiting the physical properties and internal microstructure of glass-ceramic materials but which can be formed spontaneously from a molten glass, i.e., no heat treatment of a glass body to cause the crystallization in situ thereof is required, as is demanded in the manufacture of conventional glass-ceramic articles. More specifically, this invention is concerned with the production of glass-ceramic articles having compositions within the BaO-Al2O 3-SiO2-F field which, when nucleated with TiO2, contain celsian (BaO.Al2O3.2SiO2) as the predominant crystal phase, and 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
2026-11-08 17:16
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0036
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
159 words
A method for making a highly crystalline glass-ceramic article consisting essentially of celsian and rutile 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 25-45% BaO, 15-30% Al 2 O 3 , 20-40% SiO 2 , 3-15% F, and 4-15% TiO 2 ; b. simultaneously cooling said melt at a rate between about 10°-1000° C./minute to a temperature about 850°-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 650°-850° C. for a sufficient length of time to cause crystallization of the celsian and rutile crystals in said glass body; and then d. cooling the crystallized body to room temperature.
Claim 2
Independent Claim
159 words
A method for making a highly crystalline glass-ceramic article consisting essentially of celsian and rutile 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 25-45% BaO, 15-30% Al 2 O 3 , 20-40% SiO 2 , 3-15% F, and 4-15% TiO 2 ; b. simultaneously cooling said melt at a rate between about 10°-1000° C./minute to a temperature about 850°-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 650°-850° C. for a sufficient length of time to cause crystallization of the celsian and rutile 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)
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 |