US3573073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Glass-ceramic article and method
Assignee: ROBERT W PFITZENMAIER
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Filing: 1968-03-18
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Granted: 1971-03-30
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Expires: 1988-03-18
Abstract
Abstract THIS INVENTION RELATES TO THE STRENGTHENING OF GLASSCERAMIC ARTICLES WHEREIN THE CRYSTAL CONTENT THEREOF CONSTITUTES THE PREDOMINANT PORTION AND OCNTAINING NEPHELINE AS THE PRINCIPAL CRYSTAL PHASE. THE STRENGTHENING IS EFFECTED THROUGH AN ION EXCHANGE REACTION OCCURRING WITHIN A SURFACE LAYER OF THE GLASS-CERAMIC ARTICLE WHEREIN POTASSIUM IONS FROM AN EXTERNAL SOURCE ARE EXCHANGED FOR SODIUM IONS IN THE NEPHELINE TO CONVERT THE NEPHELINE AT LEAST IN PART TO KALSILITE AND CAUSE COMPRESSIVE STRESSES TO BE DEVELOPED IN THE SURFACE LAYER.
Inventors
- 👤 David A Duke
- 👤 Bruce R Karstetter
- 👤 Stanley S Lewek
- 👤 Robert W Pfitzenmaier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:32
CPC Classifications
C; C03; C03B; C03B23/00; C03B23/04; C03B23/08; C03B23/09; C03B23/095; C03C; C03C10/00; C03C10/0018; C03C21/00; C03C21/001; C03C21/002; Y; Y10; Y10T; Y10T428/00; Y10T428/31; Y10T428/315
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-29 | 1974-09-28 | 1975-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-29 | 1978-09-28 | 1979-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-29 | 1982-09-28 | 1983-03-30 | $7700.00 | Window Closed / Lapsed |