US4184885A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alumina core having a high degree of porosity and crushability characteristics
Assignee: General Electric Co
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Filing: 1979-01-25
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Granted: 1980-01-22
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Expires: 1999-01-25
Abstract
Abstract A fired alumina article having a core of material having from 20 to 65 percent continuous porosity by volume and desired crushability characteristics and an integral outer barrier layer consisting of porous alumina having a density gradient.
Inventors
- 👤 Wayne D. Pasco
- 👤 Frederic J. Klug
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:05
CPC Classifications
B; B22; B22C; B22C9/00; B22C9/10; C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249955; Y10T428/249967; Y10T428/24997
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
98 words
A fired ceramic article suitable for use as a core in the investment casting of the directionally solidified eutectic and superalloy material consisting essentially of a porous body of alumina ceramic material having a continuous porosity content by volume of from 20 percent to 65 percent, and an integral outer barrier layer of dense alumina material having a continuous porosity throughout and a density gradient for the thickness of the barrier layer, wherein the pore size in the barrier layer is sufficiently small to prevent the penetration of any metal cast and solidified in contact with the article.
Claim 2
Dependent Claim
98 words
A fired ceramic article suitable for use as a core in the investment casting of the directionally solidified eutectic and superalloy material consisting essentially of a porous body of alumina ceramic material having a continuous porosity content by volume of from 20 percent to 65 percent, and an integral outer barrier layer of dense alumina material having a continuous porosity throughout and a density gradient for the thickness of the barrier layer, wherein the pore size in the barrier layer is sufficiently small to prevent the penetration of any metal cast and solidified in contact with the article.
Claim 3
Dependent Claim
29 words
The ceramic article of claim 1 wherein the density of the alumina increases in a direction from the center of the article toward the outer surface of the article.
Claim 4
Dependent Claim
30 words
The ceramic article of either claim 1 or 2 wherein the microstructure of the article has a grain morphology which is characteristic of grains which have undergone vapor phase transport.
Claim 5
Dependent Claim
23 words
The ceramic article of either claim 1 or 2 wherein the porosity content, by volume, of the body is greater than 30 percent.
Claim 6
Dependent Claim
22 words
The ceramic article of claim 4 wherein the porosity content, by volume, of the body is from 40 percent to 60 percent.
Claim 7
Dependent Claim
22 words
The ceramic article of claim 4 wherein the porosity content, by volume, of the body is from 45 percent to 55 percent.
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) | 1983-01-21 | 1983-07-23 | 1984-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-21 | 1987-07-23 | 1988-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-21 | 1991-07-23 | 1992-01-22 | $7700.00 | Window Closed / Lapsed |