Patent US3983198A successfully refreshed from Google Patents.
US3983198A
Expired / Lapsed
US
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Method of increasing the oxidation resistance of silicon nitride
Assignee: Ford Motor Co
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Filing: 1975-02-12
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Granted: 1976-09-28
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Expires: 1995-02-12
Abstract
Abstract A method of increasing the oxidation resistance of silicon nitride is disclosed. A furnace is preheated to a temperature in the range of 2500°F to 2750°F. The silicon nitride body to be treated is inserted into the preheated furnace. The silicon nitride article is maintained in the furance for a period of time sufficient to develop an oxidation resistant surface on the article. The period of time is generally in the range from one-half hour to five hours.
Inventors
- 👤 John A. Mangels
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:35
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B41/0072; C04B41/80
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
59 words
A method of increasing the oxidation resistance of a silicon nitride article which comprises the steps of: preheating a furnace containing an oxidizing atmosphere to a temperature in a range from 2500° F to 2750° F; inserting the silicon nitride article into the preheated furnace; and maintaining the silicon nitride article in the furnace for a period of time
Claim 2
Independent Claim
59 words
A method of increasing the oxidation resistance of a silicon nitride article which comprises the steps of: preheating a furnace containing an oxidizing atmosphere to a temperature in a range from 2500° F to 2750° F; inserting the silicon nitride article into the preheated furnace; and maintaining the silicon nitride article in the furnace for a period of time
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein: said period of time is from one-half hour
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein: said temperature is 2500° F, and
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein: said temperature is 2700° F and
Claim 6
Dependent Claim
14 words
The method of claim 1 wherein: an oxidizing atmosphere is established in said furnace.
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) | 1979-09-28 | 1980-03-29 | 1980-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-28 | 1984-03-29 | 1984-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-28 | 1988-03-29 | 1988-09-28 | $7700.00 | Window Closed / Lapsed |