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US4018612A Expired / Lapsed US ⏱️ 0.0 years remaining

Transparent beta-quartz glass-ceramics

Assignee: Corning Glass Works
•
Filing: 1976-03-25
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Granted: 1977-04-19
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Expires: 1996-03-25
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Abstract

Abstract This invention is concerned with the production of highly-crystalline, transparent glass-ceramic articles, wherein the predominant crystal phase is a beta-quartz solid solution, and which exhibit transmittances of infra-red radiations in excess of 75%, and, frequently in excess of 85%, at a wave length of 2.5 microns in articles having cross sections of about 3 mm. The articles also demonstrate excellent resistance to attack by acids and detergents, and possess coefficients of thermal expansion over the range of room temperature (R.T.) to 600° C. of less than 10 × 10 - 7 /° C. Compositions operable in the invention are encompassed within a very narrow range of the Li 2 O--MgO--ZnO--Al 2 O 3 --SiO 2 quinary nucleated with a combination of TiO 2 + ZrO 2 . Where desired, coloring agents conventional in the glass art can be added to yield colored, transparent, glass-ceramic articles.

Inventors

  • 👤 Kenneth Chyung

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 10:52
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0036; C03C10/0045; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/904

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 153 words
A transparent glass-ceramic article exhibiting a coefficient of thermal expansion (R.T.-600° C.) less than about 10 × 10 - 7 /° C., excellent chemical durability and resistance to detergent attack, an infra-red transmittance at a wave length of 2.5 microns through a polished plate of about 3 mm. thickness of in excess of 75%, and wherein beta-quartz solid solution constitutes the predominant crystal phase, said glass-ceramic article being crystallized in situ from a parent glass having a viscosity at the liquidus of at least 10,000 poises and consisting essentially, by weight on the oxide basis, of 2.5-3.5% Li 2 O, 1.5-2.5% MgO, 1-2% ZnO, 17.75-20% Al 2 O 3 , 67-70% SiO 2 , 2-4.5% TiO 2 , O-2% BaO, and 1-2% ZrO 2 , and wherein alkali metal oxides other than Li 2 O, alkaline earth metal oxides other than MgO and BaO, and B 2 O 3 are essentially absent therefrom.
Claim 2
Dependent Claim 153 words
A transparent glass-ceramic article exhibiting a coefficient of thermal expansion (R.T.-600° C.) less than about 10 × 10 - 7 /° C., excellent chemical durability and resistance to detergent attack, an infra-red transmittance at a wave length of 2.5 microns through a polished plate of about 3 mm. thickness of in excess of 75%, and wherein beta-quartz solid solution constitutes the predominant crystal phase, said glass-ceramic article being crystallized in situ from a parent glass having a viscosity at the liquidus of at least 10,000 poises and consisting essentially, by weight on the oxide basis, of 2.5-3.5% Li 2 O, 1.5-2.5% MgO, 1-2% ZnO, 17.75-20% Al 2 O 3 , 67-70% SiO 2 , 2-4.5% TiO 2 , O-2% BaO, and 1-2% ZrO 2 , and wherein alkali metal oxides other than Li 2 O, alkaline earth metal oxides other than MgO and BaO, and B 2 O 3 are essentially absent therefrom.

References Cited (Backward Citations)

US3113009A Cited
US3252811A Cited
US3625718A Cited
US3677785A Cited
US3928229A Cited
US3775154A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1980-04-18 1980-10-18 1981-04-19 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1984-04-18 1984-10-18 1985-04-19 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1988-04-18 1988-10-18 1989-04-19 $7700.00 Window Closed / Lapsed

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