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US4608348A Expired / Lapsed US ⏱️ 0.0 years remaining

Glass-ceramics containing cristobalite and potassium fluorrichterite

Assignee: Corning Glass Works
•
Filing: 1985-11-04
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Granted: 1986-08-26
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Expires: 2005-11-04
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Abstract

Abstract This invention is directed to the production of glass-ceramic articles exhibiting great toughness, a modulus of rupture of at least 20,000 psi, and, in the form of bars having dimensions 5"×0.5"×0.1", sagging during the crystallization heat treatment of no more than 0.2" over a 4" span, and wherein potassium fluorrichterite constitutes the predominant crystal phase but wherein cristobalite is also present in an amount of at least 10% by volume. The inventive articles having an overall composition consisting essentially, in weight percent on the oxide basis, of: ______________________________________ SiO 2 65-69 Na 2 O 1.5-3.3 Al 2 O 3 0.75-3.5 K 2 O 4.2-6.0 MgO 13.5-17.5 BaO 0-2.5 CaO 3-4.8 P 2 O 5 `0-2.5 Li 2 O 0.5-2.0 F 3.3-5.5 ______________________________________

Inventors

  • 👤 George H. Beall
  • 👤 John E. Megles, Jr.
  • 👤 Linda R. Pinckney

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-07 06:39
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/16; C03B; C03B32/00; C03B32/02; C03C10/0036; C03C10/0045; C03C4/00; C03C2204/00

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 112 words
A highly crystalline glass-ceramic article exhibiting great toughness, a modulus of rupture of at least 20,000 psi, and, in the form of bars having dimensions 5"×0.5"×0.1", sagging during the crystallization heat treatment of no more than 0.2" over a 4" span, and wherein potassium fluorrichterite constitutes the predominant crystal phase, but wherein cristobalite is also present in an amount of at least 10% by volume, said glass-ceramic article having an overall composition consisting essentially, expressed in terms of weight percent on the oxide basis, of ______________________________________ SiO.sub.2 65-69 Na.sub.2 O 1.5-3.3 Al.sub.2 O.sub.3 0.75-3.5 K.sub.2 O 4.2-6.0 MgO 13.5-17.5 BaO 0-2.5 CaO 3-4.8 P.sub.2 O.sub.5 `0-2.5 Li.sub.2 O 0.5-2.0 F 3.3-5.5 ______________________________________
Claim 2
Dependent Claim 112 words
A highly crystalline glass-ceramic article exhibiting great toughness, a modulus of rupture of at least 20,000 psi, and, in the form of bars having dimensions 5"×0.5"×0.1", sagging during the crystallization heat treatment of no more than 0.2" over a 4" span, and wherein potassium fluorrichterite constitutes the predominant crystal phase, but wherein cristobalite is also present in an amount of at least 10% by volume, said glass-ceramic article having an overall composition consisting essentially, expressed in terms of weight percent on the oxide basis, of ______________________________________ SiO.sub.2 65-69 Na.sub.2 O 1.5-3.3 Al.sub.2 O.sub.3 0.75-3.5 K.sub.2 O 4.2-6.0 MgO 13.5-17.5 BaO 0-2.5 CaO 3-4.8 P.sub.2 O.sub.5 `0-2.5 Li.sub.2 O 0.5-2.0 F 3.3-5.5 ______________________________________
Claim 3
Dependent Claim 38 words
A glass-ceramic article according to claim 1 also containing up to 5 mole percent total of compatible metal oxides selected from the group of SrO, TiO 2 , B 2 O 3 , ZrO 2 , and ZnO.
Claim 4
Dependent Claim 56 words
A glass-ceramic article according to claim 1 also containing up to about 5% by weight of colorants selected from the group of CdO, CoO, Cr 2 O 3 , Fe 2 O 3 , MnO 2 , NiO, CdS, Er 2 O 3 , Nd 2 O 3 , Se, and V 2 O 5 .

References Cited (Backward Citations)

US4467039A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1989-08-25 1990-02-24 1990-08-26 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1993-08-25 1994-02-24 1994-08-26 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1997-08-25 1998-02-24 1998-08-26 $7700.00 Window Closed / Lapsed

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