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US4526872A
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Transparent glass-ceramic of light brown color and method of making
Assignee: Corning Glass Works
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Filing: 1984-02-22
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Granted: 1985-07-02
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Expires: 2004-02-22
Abstract
Abstract The present invention is primarily concerned with the production of transparent glass-ceramic articles especially suitable for use as cooking utensils nucleated with up to 6% TiO 2 and containing up to 0.25% Fe 2 O 3 and, perhaps, up to 0.1% MnO 2 , which exhibits a light brown tint that the human eye perceives essentially constant when the dominant wavelength is held between 577-581 nm, purity between 8-15%, and the transmission factor between about 65-80. The desired tint is obtained by including 0.0025-0.02% CoO+Cr 2 O 3 , consisting of 0.001-0.01% CoO and 0.001-0.01% Cr 2 O 3 , in the base composition of the glass-ceramic. An opaque glass-ceramic article exhibiting a light, warm creamy color perceived by the human eye as essentially constant when the dominant wavelength is held between 570-585 nm, the reflectance factor is in excess of 64, and the purity factor is no greater than 8% can be produced from like base compositions which are crystallized in situ at higher temperatures.
Inventors
- 👤 Andre Andrieu
- 👤 Jean-Pierre P. Davot
- 👤 Jean-Pierre A. M. Thibieroz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:32
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0018; C03C10/0027; C03C1/00; C03C1/10; C03C4/00; C03C4/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
120 words
A transparent glass-ceramic article wherein β-quartz solid solution constitutes the predominant crystal phase exhibiting a light brown tint perceived by the human eye as essentially constant when the dominant wave length lies between 577-581 nm, the purity between 8-15%, and the transmission faction between 65-80, consisting essentially, expressed in terms of weight percent on the oxide basis, of about ______________________________________
SiO.sub.2
62-70 TiO.sub.2 1.8-6
Al.sub.2 O.sub.3
17.75-21.5 Fe.sub.2 O.sub.3
0-0.25
MgO 1-2.5 As.sub.2 O.sub.3
0-1
ZnO 0.5-6 CoO 0.001-0.01
Li.sub.2 O
2.5-3.5 Cr.sub.2 O.sub.3
0.001-0.01
BaO 0-2 CoO + Cr.sub.2 O.sub.3
0.0025-0.02
ZrO.sub.2
1-2.5
______________________________________ wherein the sum of alkali metal oxides other than Li 2 O and alkaline earth metal oxides rather than BaO does not exceed about 0.5%.
Claim 2
Dependent Claim
120 words
A transparent glass-ceramic article wherein β-quartz solid solution constitutes the predominant crystal phase exhibiting a light brown tint perceived by the human eye as essentially constant when the dominant wave length lies between 577-581 nm, the purity between 8-15%, and the transmission faction between 65-80, consisting essentially, expressed in terms of weight percent on the oxide basis, of about ______________________________________
SiO.sub.2
62-70 TiO.sub.2 1.8-6
Al.sub.2 O.sub.3
17.75-21.5 Fe.sub.2 O.sub.3
0-0.25
MgO 1-2.5 As.sub.2 O.sub.3
0-1
ZnO 0.5-6 CoO 0.001-0.01
Li.sub.2 O
2.5-3.5 Cr.sub.2 O.sub.3
0.001-0.01
BaO 0-2 CoO + Cr.sub.2 O.sub.3
0.0025-0.02
ZrO.sub.2
1-2.5
______________________________________ wherein the sum of alkali metal oxides other than Li 2 O and alkaline earth metal oxides rather than BaO does not exceed about 0.5%.
Claim 3
Dependent Claim
28 words
A transparent glass-ceramic article according to claim 1 wherein said base composition also contains up to 0.005% V 2 O 5 and/or up to 0.1% MnO 2 .
Claim 4
Dependent Claim
126 words
A opaque glass-ceramic article wherein β-spodumene solid solution constitutes the predominant crystal phase, exhibiting a light, warm creamy color perceived by the human eye as essentially constant when the dominant wave length lies between 570-585 nm, the reflectance factor is in excess of 64, and the purity no greater than 8%, consisting essentially, expressed in terms of weight percent on the oxide basis, of about ______________________________________
SiO.sub.2
62-70 TiO.sub.2 1.8-6
Al.sub.2 O.sub.3
17.75-21.5 Fe.sub.2 O.sub.3
0-0.25
MgO 1-2.5 As.sub.2 O.sub.3
0-1
ZnO 0.5-6 CoO 0.001-0.01
Li.sub.2 O
2.5-3.5 Cr.sub.2 O.sub.3
0.001-0.01
BaO 0-2 CoO + Cr.sub.2 O.sub.3
0.0025-0.02
ZrO.sub.2
1-2.5
______________________________________ wherein the sum of alkali metal oxides other than Li 2 O and alkaline earth metal oxides other than BaO does not exceed about 0.5%.
Claim 5
Dependent Claim
126 words
A opaque glass-ceramic article wherein β-spodumene solid solution constitutes the predominant crystal phase, exhibiting a light, warm creamy color perceived by the human eye as essentially constant when the dominant wave length lies between 570-585 nm, the reflectance factor is in excess of 64, and the purity no greater than 8%, consisting essentially, expressed in terms of weight percent on the oxide basis, of about ______________________________________
SiO.sub.2
62-70 TiO.sub.2 1.8-6
Al.sub.2 O.sub.3
17.75-21.5 Fe.sub.2 O.sub.3
0-0.25
MgO 1-2.5 As.sub.2 O.sub.3
0-1
ZnO 0.5-6 CoO 0.001-0.01
Li.sub.2 O
2.5-3.5 Cr.sub.2 O.sub.3
0.001-0.01
BaO 0-2 CoO + Cr.sub.2 O.sub.3
0.0025-0.02
ZrO.sub.2
1-2.5
______________________________________ wherein the sum of alkali metal oxides other than Li 2 O and alkaline earth metal oxides other than BaO does not exceed about 0.5%.
Claim 6
Dependent Claim
28 words
An opaque glass-ceramic article according to claim 3 wherein said base compositions also contains up to 0.002% V 2 O 5 and/or up to 0.1% MnO 2 .
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US4009042A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-07-01 | 1988-12-31 | 1989-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-01 | 1992-12-31 | 1993-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-01 | 1996-12-31 | 1997-07-02 | $7700.00 | Window Closed / Lapsed |