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US4396720A
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Transparent glass-ceramics containing mullite
Assignee: Corning Glass Works
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Filing: 1982-07-06
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Granted: 1983-08-02
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Expires: 2002-07-06
Abstract
Abstract This invention is concerned with the production of substantially transparent glass-ceramic articles containing mullite as the predominant crystal phase which can be prepared by crystallizing in situ precursor glasses capable of being melted at temperatures no higher than 1650° C. The inventive articles consist essentially, in weight percent, of 1070% SiO 2 , 7-40% B 2 O 3 , 14-50% Al 2 O 3 , 0-35% RO, wherein RO consists of at least one member of the group in the indicated proportions of 015% MgO, 0-20% CaO, 0-30% SrO, 0-30% BaO, and 0-30% PbO, and 0-30% R 2 O, wherein R 2 O consists of at least one member of the group in the indicated proportions of 0-10% Li 2 O, 0-15% Na 2 O, 0-25% K 2 O, 0-25% Rb 2 O, and 0-25% Cs 2 O, the mole ratio Al 2 O 3 :RO+R 2 O>1.3. Where 0.01-1% Cr 2 O 3 is included in the composition, the glass-ceramic will exhibit broad absorption over the visible region of the radiation spectrum, strong fluorescence in the red and near infrared portions of the spectrum where exposed to ultraviolet and/or visible radiation, and relatively little overlap of the absorption and fluorescent spectra.
Inventors
- 👤 George H. Beall
- 👤 John F. MacDowell
- 👤 Mark P. Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:39
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0054
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
102 words
A substantially transparent glass-ceramic article containing mullite as the predominant crystal phase which can be prepared from a precursor glass capable of being melted at temperatures no higher than 1650° C. and which can be crystallized at high viscosities, i.e., about 10 9 -10 12 poises, said glass-ceramic article consisting essentially, expressed in terms of weight percent on the oxide basis, of 40-60% SiO 2 , 12-30% B 2 O 3 , 17.5-27.5% Al 2 O 3 , and 3-13% Na 2 O and/or K 2 O, and wherein the mole ratio Al 2 O 3 :Na 2 O+K 2 O 1.75.
Claim 2
Dependent Claim
102 words
A substantially transparent glass-ceramic article containing mullite as the predominant crystal phase which can be prepared from a precursor glass capable of being melted at temperatures no higher than 1650° C. and which can be crystallized at high viscosities, i.e., about 10 9 -10 12 poises, said glass-ceramic article consisting essentially, expressed in terms of weight percent on the oxide basis, of 40-60% SiO 2 , 12-30% B 2 O 3 , 17.5-27.5% Al 2 O 3 , and 3-13% Na 2 O and/or K 2 O, and wherein the mole ratio Al 2 O 3 :Na 2 O+K 2 O 1.75.
Claim 3
Dependent Claim
118 words
A substantially transparent glass-ceramic article containing mullite as the predominant crystal phase which can be prepared from a precursor glass capable of being melted at temperatures no higher than 1650° C. and which can be crystallized in situ at high viscosities, i.e., about 10 9 -10 12 poises, said glass-ceramic article consisting essentially, expressed in terms of weight percent on the oxide basis, of 15-45% SiO 2 , 20-30% B 2 O 3 , 20-40% Al 2 O 3 , and 5-30% RO, wherein RO consists of at least one member of the group in the indicated proportions of 0-15% MgO, 0-20% CaO, 0-30% SrO, and 0-30% BaO, and wherein the mole ratio Al 2 O 3 :RO<1.75.
Claim 4
Dependent Claim
118 words
A substantially transparent glass-ceramic article containing mullite as the predominant crystal phase which can be prepared from a precursor glass capable of being melted at temperatures no higher than 1650° C. and which can be crystallized in situ at high viscosities, i.e., about 10 9 -10 12 poises, said glass-ceramic article consisting essentially, expressed in terms of weight percent on the oxide basis, of 15-45% SiO 2 , 20-30% B 2 O 3 , 20-40% Al 2 O 3 , and 5-30% RO, wherein RO consists of at least one member of the group in the indicated proportions of 0-15% MgO, 0-20% CaO, 0-30% SrO, and 0-30% BaO, and wherein the mole ratio Al 2 O 3 :RO<1.75.
Claim 5
Dependent Claim
28 words
A glass-ceramic according to claim 1 also containing up to 1% total of transition metal oxides and/or up to 5% total of rare earth metal oxides as colorants.
Claim 6
Dependent Claim
28 words
A glass-ceramic according to claim 2 also containing up to 1% total of transition metal oxides and/or up to 5% total of rare earth metal oxides as colorants.
Claim 7
Dependent Claim
55 words
A glass-ceramic according to claim 1, which, also containing 0.01-1% Cr 2 O 3 , demonstrates broad absorption over the visible region of the radiation spectrum, strong fluorescence in the red and near infrared portions of the spectrum when exposed to ultraviolet and/or visible radiation, and relatively little overlap of the absorption and fluorescent spectra.
Claim 8
Dependent Claim
55 words
A glass-ceramic according to claim 2 which, also containing 0.01-1% Cr 2 O 3 , demonstrates broad absorption over the visible region of the radiation spectrum, strong fluorescence in the red and near infrared portions of the spectrum when exposed to ultraviolet and/or visible radiation, and relatively little overlap of the absorption and fluorescent spectra.
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) | 1986-08-01 | 1987-01-31 | 1987-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-01 | 1991-01-31 | 1991-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-01 | 1995-01-31 | 1995-08-02 | $7700.00 | Window Closed / Lapsed |