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US3873329A Expired / Lapsed US ⏱️ 0.0 years remaining

Glass-ceramic article

Assignee: Corning Glass Works
•
Filing: 1973-07-02
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Granted: 1975-03-25
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Expires: 1993-07-02
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Abstract

Abstract This invention relates to the production of hard, high-modulus glass-ceramic articles having compositions within the MgO-Al2O3B2O3-SiO2 field nucleated with a combination of TiO2 and ZrO2 wherein the principal crystal phases are alpha-quartz and sapphirine. Where such articles are contacted with a source of lithium ions at elevated temperatures, an exchange of lithium ions for magnesium ions on a two-Li -for-one Mg 2basis takes place within the crystal structures resulting in the development of a surface layer wherein the primary crystal phase is a lithium-stuffed beta-quartz solid solution, also sometimes termed beta-eucryptite solid solution. This phenomenon causes the development of compressive stresses within the ion exchanged surface layer as the articles are cooled below the exchange temperature leading to a marked improvement in the mechanical strength of the articles.

Inventors

  • 👤 George H Beall

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 18:50
CPC Classifications
C; C03; C03B; C03B32/00; C03B32/02; C03C; C03C10/00; C03C10/0036; C03C10/0045; C03C21/00

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 103 words
A GLASS-CERAMIC ARTICLE EXHIBITING A MODULUS OF RUPTURE VALUE AS FORMED BETWEEN ABOUT 25,000-60,000 PSI, A KNOOP HARDNESS MEASUREMENT (KHN100) GREATER THAN 800, AND A COEFFICIENT OF THERMAL EXPANSION (25*-300*C.) BETWEEN ABOUT 90-110 X 10**-7/*C. CONSISTING PREDOMINANTLY OF ALPHA-QUARTZ AND SAPPHIRINE HOMOGENEOUSLY DISPERSED WITHIN A GLASSY MATRIX, THE TOTAL CRYSTALLINITY COMPRISING AT LEAST 75 PERCENT OF THE GLASS-CERAMIC ARTICLE AND BEING PRODUCED THROUGH THE CRYSTALLIZATION IN SITU OF A GLASS ARTICLE CONSISTING ESSENTIALLY, BY WEIGHT ON THE OXIDE BASIS, OF ABOUT 10-16 PERCENT MGO, 0.5-3.5% B2O3, 20-28 PERCENT AL2O3, 44-58 PERCENT SIO2, 3-9% TIO2, AND 3-7% ZRO2, THE TOTAL TIO2+ZRO2 BEING ABOUT 8-13%
Claim 2
Dependent Claim 103 words
A GLASS-CERAMIC ARTICLE EXHIBITING A MODULUS OF RUPTURE VALUE AS FORMED BETWEEN ABOUT 25,000-60,000 PSI, A KNOOP HARDNESS MEASUREMENT (KHN100) GREATER THAN 800, AND A COEFFICIENT OF THERMAL EXPANSION (25*-300*C.) BETWEEN ABOUT 90-110 X 10**-7/*C. CONSISTING PREDOMINANTLY OF ALPHA-QUARTZ AND SAPPHIRINE HOMOGENEOUSLY DISPERSED WITHIN A GLASSY MATRIX, THE TOTAL CRYSTALLINITY COMPRISING AT LEAST 75 PERCENT OF THE GLASS-CERAMIC ARTICLE AND BEING PRODUCED THROUGH THE CRYSTALLIZATION IN SITU OF A GLASS ARTICLE CONSISTING ESSENTIALLY, BY WEIGHT ON THE OXIDE BASIS, OF ABOUT 10-16 PERCENT MGO, 0.5-3.5% B2O3, 20-28 PERCENT AL2O3, 44-58 PERCENT SIO2, 3-9% TIO2, AND 3-7% ZRO2, THE TOTAL TIO2+ZRO2 BEING ABOUT 8-13%
Claim 3
Dependent Claim 16 words
A glass-ceramic article according to claim 1 wherein the mole ratio Si2O4:MgAl2O4 is below about 3:2.
Claim 4
Dependent Claim 17 words
A glass-ceramic article according to claim 2 wherein the mole ratio Si2O4:MgAl2O4 is greater than about 1:1.
Claim 5
Dependent Claim 28 words
A glass-ceramic article according to claim 1 wherein the sum of MgO, B2O3, Al2O3, SiO2, TiO2, and ZrO2 constitutes about 97 percent by weight of the total composition.

References Cited (Backward Citations)

US3117881A Cited
US3252778A Cited
US3647490A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-03-24 1978-09-23 1979-03-25 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-03-24 1982-09-23 1983-03-25 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-03-24 1986-09-23 1987-03-25 $7700.00 Window Closed / Lapsed

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