US4031177A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the manufacture of articles of translucent alumina
Assignee: Compagnie General dElectro Ceramique SA
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Filing: 1975-10-17
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Granted: 1977-06-21
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Expires: 1995-10-17
Abstract
Abstract Final sintering of an alumina powder containing a small portion of magnesia, baryta, lanthana, yttria, or salts of magnesium, barium, lanthanum or yttrium, in a non-oxidizing carbon monoxide atmosphere at a temperature above 1700° C produces a translucent alumina article.
Inventors
- 👤 Alain Auriol
- 👤 Paul Tritten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:09
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/01; C04B35/10; C04B35/111; C04B35/115; Y; Y10; Y10S; Y10S264/00; Y10S264/91
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
79 words
In a process for manufacturing articles of translucent alumina by sintering articles molded from a very pure fine powder containing a small portion of a grain-growth inhibiting substance, comprising the steps of: a. preliminarily sintering said powder in an oxidizing atmosphere at a temperature between about 700° C and about 1100° C., followed by b. final sintering at a temperature above 1700° C., in a nonoxidizing medium, the improvement which comprises conducting final sintering in a carbon monoxide atmosphere.
Claim 2
Dependent Claim
79 words
In a process for manufacturing articles of translucent alumina by sintering articles molded from a very pure fine powder containing a small portion of a grain-growth inhibiting substance, comprising the steps of: a. preliminarily sintering said powder in an oxidizing atmosphere at a temperature between about 700° C and about 1100° C., followed by b. final sintering at a temperature above 1700° C., in a nonoxidizing medium, the improvement which comprises conducting final sintering in a carbon monoxide atmosphere.
Claim 3
Dependent Claim
20 words
The process of claim 1, wherein the preliminary sintering takes place at a temperature of from 800° to 1100° C.
Claim 4
Dependent Claim
23 words
The process of claim 1, wherein the final sintering takes place under a partial carbon monoxide pressure above or equal to 670 millibars.
Claim 5
Dependent Claim
19 words
The process of claim 3, wherein the final sintering takes place at about 1850° C for about 5 hours.
Claim 6
Dependent Claim
20 words
The process of claim 1, wherein the final sintering takes place in a carbon monoxide atmosphere containing an inert gas.
Claim 7
Dependent Claim
21 words
The process of claim 1, wherein the final sintering takes place in a carbon monoxide atmosphere in the presence of carbon.
References Cited (Backward Citations)
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Cited
US3377176A
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US3641227A
Cited
US3679383A
Cited
US3615306A
Cited
US3711585A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-20 | 1980-12-20 | 1981-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-20 | 1984-12-20 | 1985-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-20 | 1988-12-20 | 1989-06-21 | $7700.00 | Window Closed / Lapsed |