US4054627A
Expired / Lapsed
US
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Dense chromium sesquioxide
Assignee: Individual
•
Filing: 1973-05-14
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Granted: 1977-10-18
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Expires: 1993-05-14
Abstract
Abstract A sintered, fine grained, polycrystalline, essentially fully dense, essentially single phase Cr 2 O 3 body is prepared by sintering Chromium Sesquioxide (Cr 2 O 3 ) at essentially the equilibrium oxygen partial pressure (P O .sbsb.2) for the formation of Cr 2 O 3 from its elements at the sintering temperature. To achieve optimum theoretical density a second metal oxide dopant such as MgO, capable of controlling the grain size, is added. In addition, Cr 2 O 3 bodies are rendered more stable, and thus have a longer life, by maintaining over the body an atmosphere which is essentially equilibrium P O .sbsb.2 for the formation of Cr 2 O 3 from its elements at that temperature.
Inventors
- 👤 Paul Darrell Ownby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:31
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/12; Y; Y10; Y10S; Y10S264/00; Y10S264/57
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
53 words
A process for producing a sintered body consisting substantially of Cr 2 O 3 up to within about 1% of theoretical density, which comprises, sintering a Cr 2 O 3 body at essentially the equilibrium oxygen partial pressure for the formation of Cr 2 O 3 from its elements at the sintering temperature.
Claim 2
Dependent Claim
53 words
A process for producing a sintered body consisting substantially of Cr 2 O 3 up to within about 1% of theoretical density, which comprises, sintering a Cr 2 O 3 body at essentially the equilibrium oxygen partial pressure for the formation of Cr 2 O 3 from its elements at the sintering temperature.
Claim 3
Dependent Claim
27 words
The process of claim 1 where the body contains in intimate mixture therewith a small but effective amount of MgO as a dopant for controlling grain growth.
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) | 1980-10-17 | 1981-04-18 | 1981-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-17 | 1985-04-18 | 1985-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-17 | 1989-04-18 | 1989-10-18 | $7700.00 | Window Closed / Lapsed |