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US3915720A Expired / Lapsed US ⏱️ 0.0 years remaining

Machinable hydrothermally-crystallized glass bodies

Assignee: Corning Glass Works
•
Filing: 1974-10-07
•
Granted: 1975-10-28
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Expires: 1994-10-07
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Abstract

Abstract The instant invention is concerned with the production of glass bodies which, after being hydrothermally crystallized, exhibit a relatively high degree of machinability and good chemical durability. Such bodies are produced by hydrating glass particles having compositions within a very narrow interval of the Na2OAl2O3-MgO-SiO2 field. The hydration simultaneously results in the development of quartz crystals and causes the glass particles to sinter together into an integrated solid body which can be readily shaped and drilled by hand and machine tools. Upon firing to remove the water in the glass structure, a porous body is produced that will exhibit no more than 10% linear shrinkage and, most preferably, less than 5%.

Inventors

  • 👤 Walter H Tarcza

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 14:35
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0036; C03C10/0045

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 57 words
A HYDRATED, SINTERED GLASS-CERAMIC BODY IN WHICH THE CRYSTALLINE PHASE IS LPHA-QUARTZ BETWEEN 25-80% BY TOTAL VOLUME, SAID BODY EXHIBITING A HIGH DEGREE OF MACHINABILITY AND GOOD CHEMICAL DURABILITY CONSISTING ESSENTIALLY, BY WEIGHT ON THE OXIDE BASIS, OF ABOUT 2-5% MGO, 2-5% A12O3, 15-20% NA2O, AND 75-80% SIO2, AND CONTAINING BETWEEN ABOUT 15-30% BY WEIGHT ABSORBED H2O.
Claim 2
Dependent Claim 57 words
A HYDRATED, SINTERED GLASS-CERAMIC BODY IN WHICH THE CRYSTALLINE PHASE IS LPHA-QUARTZ BETWEEN 25-80% BY TOTAL VOLUME, SAID BODY EXHIBITING A HIGH DEGREE OF MACHINABILITY AND GOOD CHEMICAL DURABILITY CONSISTING ESSENTIALLY, BY WEIGHT ON THE OXIDE BASIS, OF ABOUT 2-5% MGO, 2-5% A12O3, 15-20% NA2O, AND 75-80% SIO2, AND CONTAINING BETWEEN ABOUT 15-30% BY WEIGHT ABSORBED H2O.

References Cited (Backward Citations)

US3498803A Cited
US3498802A Cited
US3811853A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-10-27 1979-04-28 1979-10-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-10-27 1983-04-28 1983-10-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-10-27 1987-04-28 1987-10-28 $7700.00 Window Closed / Lapsed

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