US4612146A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the hot-isostatic compression of ceramic shaped parts
Assignee: MTU Aero Engines AG
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Filing: 1984-06-21
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Granted: 1986-09-16
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Expires: 2004-06-21
Abstract
Abstract A ceramic preform is coated with a layer of amorphous carbon and is then hot-isostatically compressed to form the desired ceramic part. The layer of carbon can then be removed.
Inventors
- 👤 Werner Huther
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:52
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/622; C04B35/64; C04B35/645; C04B35/6455
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
70 words
A process for the manufacture of a shaped ceramic part comprising applying a resin coat on a preform of silicon nitride or silicon carbide, heating the resin coat to form a gas impermeable coating of amorphous carbon therefrom on said preform, hot-isostatically compressing the preform with the amorphous carbon coating thereon to form a shaped ceramic part with the amorphous carbon coating, and then burning off the amorphous carbon coating.
Claim 2
Dependent Claim
70 words
A process for the manufacture of a shaped ceramic part comprising applying a resin coat on a preform of silicon nitride or silicon carbide, heating the resin coat to form a gas impermeable coating of amorphous carbon therefrom on said preform, hot-isostatically compressing the preform with the amorphous carbon coating thereon to form a shaped ceramic part with the amorphous carbon coating, and then burning off the amorphous carbon coating.
Claim 3
Dependent Claim
30 words
A process as claimed in claim 1 wherein the resin coat is formed by at least one coat of a phenol resin, epoxy resin or polyimide resin on the preform.
Claim 4
Dependent Claim
28 words
A process as claimed in claim 2 which further includes the step of curing the resin coat on the preform by heat treatment at 150° to 250° C.
Claim 5
Dependent Claim
22 words
A process as claimed in claim 1 wherein said heating comprises slow heating of the preform in an inert gas or vacuum.
Claim 6
Dependent Claim
23 words
A process as claimed in claim 2 wherein the heating is carried out after each application of a resin coating on the preform.
Claim 7
Dependent Claim
31 words
A process as claimed in claim 5 wherein the heating of the first resin layer is carried out under pressure and any subsequent heat treatment is carried out in a vacuum.
Claim 8
Dependent Claim
26 words
A process as claimed in claim 1 wherein the preform comprises reaction-bonded silicon nitride which contains 0.5 to 5% MgO or Y 2 O 3 .
Claim 9
Dependent Claim
34 words
A process as claimed in claim 1 wherein the preform comprises a powder preform of Si 3 N 4 powder having an average particle size of 1 to 2μ and a purity of 99%.
Claim 10
Dependent Claim
24 words
A process as claimed in claim 8 wherein the powder preform comprises a sintering promoting additive of MgO or Y 2 O 3 powder.
Claim 11
Dependent Claim
31 words
A process as claimed in claim 1 wherein said preform comprises a powder preform of silicon carbide having an average particle size of 1 to 2μ and a purity of 98%.
Claim 12
Dependent Claim
18 words
A process as claimed in claim 10 wherein the silicon carbide preform includes additives which prevent grain growth.
Claim 13
Dependent Claim
28 words
A process as claimed in claim 1 wherein the amorphous carbon coating is burned off the shaped part at a temperature of 600° to 1200° C. in air.
Claim 14
Dependent Claim
28 words
A process as claimed in claim 2 wherein the amorphous carbon coating is burned off the shaped part at a temperature of 600° to 1200° C. in air.
References Cited (Backward Citations)
US4112143A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-09-15 | 1990-03-17 | 1990-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-15 | 1994-03-17 | 1994-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-15 | 1998-03-17 | 1998-09-16 | $7700.00 | Window Closed / Lapsed |