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US4013477A
Expired / Lapsed
US
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Method for preparing dense, β-alumina ceramic bodies
Assignee: University of Utah
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Filing: 1975-07-30
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Granted: 1977-03-22
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Expires: 1995-07-30
Abstract
Abstract A method for preparing a dense and strong polycrystalline beta ''-alumina-containing ceramic body exhibiting an elecrical resistivity at 300 DEG C of 5 ohm-cm or lower, and a controlled and uniform grain size under 50 micrometers, comprising:
Inventors
- 👤 Arun D. Jatkar
- 👤 Ivan B. Cutler
- 👤 Anil V. Virkar
- 👤 Ronald S. Gordon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:12
CPC Classifications
H; H01; H01M; H01M10/00; H01M10/36; H01M10/39; H01M10/3909; H01M10/3918; C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/113; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
112 words
In a process for forming a β"-alumina containing ceramic body comprising A. forming a green ceramic body from a matrix powder which is of a composition consistent with the formation of β"-alumina upon sintering and B. sintering said green ceramic body at a temperature and for a time necessary to achieve the desired final density and convert said composition to β"-alumina, the improvement comprising mechanically mixing said matrix powder, with β"-alumina seed crystals prior to forming said green ceramic body, said seed crystals having a particle size up to 100 micrometers, the amount of said crystals ranging up to 50% by weight of said total mixture of seed crystals and matrix powder.
Claim 2
Dependent Claim
112 words
In a process for forming a β"-alumina containing ceramic body comprising A. forming a green ceramic body from a matrix powder which is of a composition consistent with the formation of β"-alumina upon sintering and B. sintering said green ceramic body at a temperature and for a time necessary to achieve the desired final density and convert said composition to β"-alumina, the improvement comprising mechanically mixing said matrix powder, with β"-alumina seed crystals prior to forming said green ceramic body, said seed crystals having a particle size up to 100 micrometers, the amount of said crystals ranging up to 50% by weight of said total mixture of seed crystals and matrix powder.
Claim 3
Dependent Claim
37 words
A process in accordance with claim 1 wherein said seed crystals are formed by sintering a body formed from the same composition as said matrix powder and comminuting the sintered β"-alumina body to the desired particle size.
Claim 4
Dependent Claim
30 words
A process in accordance with claim 1 wherein said β"-alumina seed crystals are admixed with said matrix powder in an amount ranging up to 10 weight percent of the mixture.
Claim 5
Dependent Claim
34 words
A process in accordance with claim 1 wherein said β"-alumina seed crystals are admixed with said matrix pwoder in an amount ranging from about 2 up to about 10 weight percent of the mixture.
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) | 1980-03-21 | 1980-09-20 | 1981-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-21 | 1984-09-20 | 1985-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-21 | 1988-09-20 | 1989-03-22 | $7700.00 | Window Closed / Lapsed |