US4341874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Si3 N4 Ceramic powder material and method for manufacturing the same
Assignee: Toshiba Corp
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Filing: 1980-12-31
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Granted: 1982-07-27
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Expires: 2000-12-31
Abstract
Abstract Ceramic powder material mainly consists of silicon nitride wherein the content of oxygen combined with generally unavoidable impurities as measured by activation analysis accounts for less than 2% by weight. The above-mentioned ceramic powder material can also be prepared preferably by the method which comprises the step of heating raw ceramic powder material mainly consisting of silicon nitride to 1,400° C. to 1,900° C. in the presence of a separately prepared nonsintered molding of ceramic material or sintered molding of ceramic material having a porosity of at least 10%.
Inventors
- 👤 Katsutoshi Nishida
- 👤 Michiyasu Komatsu
- 👤 Tadashi Miyano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:06
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
110 words
A ceramic powder material consisting essentially of silicon nitride powder consisting essentially of from 0.05 to 2.5% by weight of aluminium and from 0.4 to 8.0% by weight of yttrium, in which all or a part of the yttrium contained in the silicon nitride powder is present in the form of a crystalline compound of silicon nitride and yttrium oxide and in which the total oxygen content W O (% by weight) as measured by activation analysis falls within the range expressed by the following formula denoting the relationship between the content of aluminium W Al (% by weight) and the content of yttrium W Y (% by weight): ##EQU2##
Claim 2
Dependent Claim
110 words
A ceramic powder material consisting essentially of silicon nitride powder consisting essentially of from 0.05 to 2.5% by weight of aluminium and from 0.4 to 8.0% by weight of yttrium, in which all or a part of the yttrium contained in the silicon nitride powder is present in the form of a crystalline compound of silicon nitride and yttrium oxide and in which the total oxygen content W O (% by weight) as measured by activation analysis falls within the range expressed by the following formula denoting the relationship between the content of aluminium W Al (% by weight) and the content of yttrium W Y (% by weight): ##EQU2##
Claim 3
Dependent Claim
28 words
The ceramic powder material according to claim 1, wherein the crystalline compound is a silicon yttrium oxynitride crystal compound (Si 3 N 4 .Y 2 O 3 ).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-26 | 1986-01-25 | 1986-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-26 | 1990-01-25 | 1990-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-26 | 1994-01-25 | 1994-07-27 | $7700.00 | Window Closed / Lapsed |