Patent US4572902A successfully refreshed from Google Patents.
US4572902A
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Method for producing ceramic sintered body of a Si3 N4 -SiC system
Assignee: Krosaki Harima Corp
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Filing: 1985-02-07
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Granted: 1986-02-25
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Expires: 2005-02-07
Abstract
Abstract After sintering, ceramic body of Si 3 N 4 -SiC is heat-treated at 500°-1500° C. in atmosphere of gas mixture of chlorine and nitrogen whereby SiC is converted into silicon chloride which in turn is nitrided to form Si 3 N 4 in the pores of the ceramic body to provide closed pore structure. Gas mixture may contain oxygen. Heat treatment may be conducted in pressurized atmosphere of gas mixture.
Inventors
- 👤 Taiji Matano
- 👤 Haruyuki Ueno
- 👤 Kazushige Fukuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:02
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/5935; C04B41/45; C04B41/50; C04B41/5053; C04B41/5062; C04B41/5066; C04B41/80; C04B41/81; C04B41/85; C04B41/87
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
81 words
A method for producing ceramics having a closed pore structure from a sintered body of a Si 3 N 4 -SiC system which includes a process for heating ceramic sintered body in an atmosphere of a flowing gas mixture containing 0.1-80% in volume of chlorine and balance nitrogen gas at the temperature range of 500°-1500° C. after sintering whereby SiC is chemically reacted to produce silicon chloride which in turn is nitrided to form Si 3 N 4 in the pores.
Claim 2
Independent Claim
81 words
A method for producing ceramics having a closed pore structure from a sintered body of a Si 3 N 4 -SiC system which includes a process for heating ceramic sintered body in an atmosphere of a flowing gas mixture containing 0.1-80% in volume of chlorine and balance nitrogen gas at the temperature range of 500°-1500° C. after sintering whereby SiC is chemically reacted to produce silicon chloride which in turn is nitrided to form Si 3 N 4 in the pores.
Claim 3
Dependent Claim
22 words
The method according to claim 1, wherein said gas mixture contains equal to or less than 50% in volume of oxygen gas.
Claim 4
Dependent Claim
23 words
The method according to claim 1, wherein said atmosphere of the gas mixture is a pressurized atmosphere of 50 kg/cm 2 and less.
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) | 1989-02-24 | 1989-08-26 | 1990-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-24 | 1993-08-26 | 1994-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-24 | 1997-08-26 | 1998-02-25 | $7700.00 | Window Closed / Lapsed |