Patent EP0140981A1 successfully refreshed from Google Patents.
US4256497A
Expired / Lapsed
US
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Lead-free glaze for alumina bodies
Assignee: Champion Aerospace LLC
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Filing: 1980-02-08
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Granted: 1981-03-17
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Expires: 2000-02-08
Abstract
Abstract A high-silica ceramic glaze, having a low coefficient of thermal expansion, suitable for application to alumina bodies, is disclosed. The glaze consists essentially, by weight percent, of 35 to 54 percent SiO 2 , from 7 to 11 percent Al 2 O 3 , from 17 to 25 percent B 2 O 3 , from 2 to 3 percent CaO, from 2 to 21/2 percent ZnO, from 41/4 to 5 percent Na 2 O, from 81/2 to 21 percent SrO, and from 0.7 to 1 percent of a mixture of K 2 O, Li 2 O and MgO, and minor impurities.
Inventors
- 👤 Randy O. Knapp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:10
CPC Classifications
C; C03; C03C; C03C8/00; C03C8/02; C03C8/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
97 words
A lead-free and barium-free ceramic glaze for application to sintered high alumina substrates and maturing at temperatures from 1800° to 2200° F. consisting essentially of from 35 to 54 percent SiO 2 , from 7 to 11 percent Al 2 O 3 , from 17 to 25 percent B 2 O 3 , from 2 to 3 percent CaO, from 2 to 21/2 percent ZnO, from 41/4 to 5 percent Na 2 O, from 81/2 to 21 percent SrO, and from 0.7 to 1 percent of a mixture of K 2 O, Li 2 O, and MgO.
Claim 2
Dependent Claim
97 words
A lead-free and barium-free ceramic glaze for application to sintered high alumina substrates and maturing at temperatures from 1800° to 2200° F. consisting essentially of from 35 to 54 percent SiO 2 , from 7 to 11 percent Al 2 O 3 , from 17 to 25 percent B 2 O 3 , from 2 to 3 percent CaO, from 2 to 21/2 percent ZnO, from 41/4 to 5 percent Na 2 O, from 81/2 to 21 percent SrO, and from 0.7 to 1 percent of a mixture of K 2 O, Li 2 O, and MgO.
Claim 3
Dependent Claim
55 words
A ceramic glaze as claimed in claim 1 consisting essentially of 521/2 percent SiO 2 , 9 percent Al 2 O 3 , 191/4 percent B 2 O 3 , 21/4 percent CaO, 43/4 percent Na 2 O, 1/2 percent K 2 O, 1/4 percent LiO 2 , 2 percent ZnO, and 91/2 percent SrO.
Claim 4
Dependent Claim
42 words
A ceramic glaze as claimed in claim 1 wherein the normalized molecular formula contains from about 0.24 to 0.35 mole of R 2 O, about 0.07 to 0.11 mole of ZnO and from 1.00 to 1.54 moles R 2 O 3 .
Claim 5
Dependent Claim
35 words
A ceramic glaze as claimed in claim 3 wherein from 0.78 mole to 1.19 moles of the R 2 O 3 in the normalized molecular formula for the glaze is B 2 O 3 .
Claim 6
Dependent Claim
23 words
A ceramic glaze as claimed in claim 4 wherein the RO in the normalized molecular formula is from substantially 0.65 to 0.75 mole.
Claim 7
Dependent Claim
27 words
A ceramic glaze as claimed in claim 5 wherein SrO constitutes from 0.33 to 0.57 mole of the RO in the normalized molecular formula for the glaze.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-16 | 1984-09-15 | 1985-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-16 | 1988-09-15 | 1989-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-16 | 1992-09-15 | 1993-03-17 | $7700.00 | Window Closed / Lapsed |