US3989496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spontaneously-formed glass-ceramics containing barium and/or strontium iron silicate crystals
Assignee: Corning Glass Works
•
Filing: 1975-03-19
•
Granted: 1976-11-02
•
Expires: 1995-03-19
Abstract
Abstract The present invention is concerned with the production of articles having the physical properties and internal microstructure normally associated with glass-ceramic articles, but which can be formed spontaneously from a molten glass batch. Hence, the instant invention avoids the heat treatment of a precursor glass body, such as is required in the manufacture of conventional glass-ceramic bodies to cause the crystallization in situ thereof. More specifically, this invention relates to the production of highly-crystalline glass-ceramic articles having compositions within the BaO and/or SrO-Fe2O3-SiO2 field, wherein BaO and/or SrO-Fe2O3-SiO2 solid solution crystals comprise the predominant crystal phase, which can be formed spontaneously from a molten glass batch.
Inventors
- 👤 Hermann L. Rittler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:56
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0009
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
171 words
A method for making a highly crystalline glass-ceramic article consisting essentially of BaO and/or SrO-Fe 2 O 3 -SiO 2 solid solution crystals with, optionally, Fe 3 O 4 dispersed within a glassy matrix, said crystals comprising 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, of about 8-20% BaO and/or 15-25% SrO, the total BaO + SrO not exceeding about 25%, 20-40% Fe 2 O 3 , and 40-70% SiO 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 a phase separation 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 solid solution phases in said glass body; and then d. cooling the crystallized body to room temperature.
Claim 2
Independent Claim
171 words
A method for making a highly crystalline glass-ceramic article consisting essentially of BaO and/or SrO-Fe 2 O 3 -SiO 2 solid solution crystals with, optionally, Fe 3 O 4 dispersed within a glassy matrix, said crystals comprising 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, of about 8-20% BaO and/or 15-25% SrO, the total BaO + SrO not exceeding about 25%, 20-40% Fe 2 O 3 , and 40-70% SiO 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 a phase separation 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 solid solution phases 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
51 words
A method according to claim 1 wherein said BaO and/or SrO-Fe 2 O 3 -SiO 2 solid solution crystals are selected from the group consisting of BaFeSi 4 O 10 , SrFeSi 4 O 10 , BaFeSi 2 O 7 , Sr 2 FeSi 2 O 7 , and mixtures thereof.
Claim 5
Dependent Claim
35 words
A method according to claim 1 wherein said glass also contains up to about 10% TiO 2 and that crystals of Ba and/or SrFe 2 TiSi 2 O 9 are present in said crystallized body.
Claim 6
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)
US3804608A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-11-02 | 1980-05-03 | 1980-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-02 | 1984-05-03 | 1984-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-02 | 1988-05-03 | 1988-11-02 | $7700.00 | Window Closed / Lapsed |