US4179486A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of protecting Si3 N4 ceramic alloy during heating
Assignee: Boeing North American Inc
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Filing: 1978-07-21
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Granted: 1979-12-18
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Expires: 1998-07-21
Abstract
Abstract Articles made from Si3N4 ceramic alloy powders are protected during heating by loosely packing them in Si3N4 before heating. Compacts made from Si3N4 ceramic alloys are protected from both oxidation and from volatilization by the encompassing powder even though the furnace atmosphere is air.
Inventors
- 👤 Frederick F. Lange
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:42
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/622; C04B35/64
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
71 words
A method of protecting a Si 3 N 4 ceramic alloy article during heating comprising the steps of: providing a Si 3 N 4 ceramic alloy article; loosely packing said article in Si 3 N 4 powder; heating said article and said powder to a processing temperature in an oxidizing atmosphere; cooling said article and said powder to a temperature below said processing temperature; and removing said article from said powder.
Claim 2
Independent Claim
71 words
A method of protecting a Si 3 N 4 ceramic alloy article during heating comprising the steps of: providing a Si 3 N 4 ceramic alloy article; loosely packing said article in Si 3 N 4 powder; heating said article and said powder to a processing temperature in an oxidizing atmosphere; cooling said article and said powder to a temperature below said processing temperature; and removing said article from said powder.
Claim 3
Dependent Claim
26 words
The method as claimed in claim 1, wherein said step of heating comprises placing said article in a furnace at atmospheric pressure having an air atmosphere.
Claim 4
Dependent Claim
20 words
The method as claimed in claim 2, wherein said step of cooling comprises furnace cooling said article and said powder.
Claim 5
Dependent Claim
32 words
The method as claimed in claim 1, wherein said Si 3 N 4 powder has a composition substantially the same as the composition of said Si 3 N 4 ceramic alloy article.
Claim 6
Dependent Claim
23 words
The method as claimed in claim 1, wherein said Si 3 N 4 powder is placed in an Al 2 O 3 container.
Claim 7
Dependent Claim
21 words
The method as claimed in claim 1, wherein said Si 3 N 4 powder is placed in an SiO 2 container.
Claim 8
Independent Claim
74 words
A method of protecting a Si 3 N 4 -CeO 2 ceramic alloy article during heating comprising the steps of: providing a Si 3 N 4 -CeO ceramic alloy article; loosely packing said article in Si 3 N 4 powder; heating said article and said powder to a processing temperature in an oxidizing atmosphere; cooling said article and said powder to a temperature below said processing temperature; and removing said article from said powder.
Claim 9
Independent Claim
74 words
A method of protecting a Si 3 N 4 -CeO 2 ceramic alloy article during heating comprising the steps of: providing a Si 3 N 4 -CeO ceramic alloy article; loosely packing said article in Si 3 N 4 powder; heating said article and said powder to a processing temperature in an oxidizing atmosphere; cooling said article and said powder to a temperature below said processing temperature; and removing said article from said powder.
Claim 10
Dependent Claim
40 words
The method as claimed in claim 7, wherein said step of heating comprises placing said article in a furnace at atmospheric pressure having an air atmosphere, and wherein said step of cooling comprises furnace cooling said article and said powder.
Claim 11
Dependent Claim
25 words
The method as claimed in claim 7, wherein said Si 3 N 4 powder comprises a Si 3 N 4 -CeO 2 ceramic alloy powder.
References Cited (Backward Citations)
US3969125A
Cited
FR2221421A1
Cited
US4143107A
Cited
US3983198A
Cited
US4101616A
Cited
US4112143A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-17 | 1983-06-18 | 1983-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-17 | 1987-06-18 | 1987-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-17 | 1991-06-18 | 1991-12-18 | $7700.00 | Window Closed / Lapsed |