Patent US4284432A successfully refreshed from Google Patents.
US4284432A
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US
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Ceramic powder material and method for manufacturing the same
Assignee: Toshiba Corp
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Filing: 1979-09-21
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Granted: 1981-08-18
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Expires: 1999-09-21
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 03:57
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
123 words
A method of reducing the oxygen content of a ceramic powder material prior to molding including the step of heating raw ceramic powder consisting essentially of silicon nitride to a temperature ranging between 1,400° C. and 1,900° C. in the presence of a nonsintered or a sintered molding of ceramic material, said molding formed of a compound selected from the group consisting of aluminum nitride, boron nitride, titanium nitride, silicon nitride and aluminum oxide and having a porosity of at least 10%, thereby reducing the amount of oxygen combined with impurities unavoidably included in said raw ceramic powder material to an amount less than 2.0% by weight as measured by activation analysis, the thus treated powder when molded exhibiting high temperature mechanical strength.
Claim 2
Independent Claim
123 words
A method of reducing the oxygen content of a ceramic powder material prior to molding including the step of heating raw ceramic powder consisting essentially of silicon nitride to a temperature ranging between 1,400° C. and 1,900° C. in the presence of a nonsintered or a sintered molding of ceramic material, said molding formed of a compound selected from the group consisting of aluminum nitride, boron nitride, titanium nitride, silicon nitride and aluminum oxide and having a porosity of at least 10%, thereby reducing the amount of oxygen combined with impurities unavoidably included in said raw ceramic powder material to an amount less than 2.0% by weight as measured by activation analysis, the thus treated powder when molded exhibiting high temperature mechanical strength.
Claim 3
Independent Claim
167 words
A method of reducing the oxygen content of a ceramic powder material prior to molding, said method including the step of heating a raw mixed ceramic powder consisting essentially of 0.1 to 5% by weight of alumina, 0.5 to 10% by weight of yttria and silicon nitride as the remainder, in the presence of a non-sintered or a sintered molding of ceramic material, said molding formed of a compound selected from the group consisting of aluminum nitride, boron nitride, titanium nitride, silicon nitride and aluminum oxide, and having a porosity of at least 10% to a temperature ranging between 1,400° C. and 1,900° C., and whereby the resulting heated mass contains 0.05 to 2.5% by weight of aluminum, and 0.4 to 8.0% by weight of yttrium; and the total oxygen content W O (% by weight) as measured by activation analysis satisfies the following formula denoting the relationship between the aluminum content W A (% by weight) and the yttrium content W Y (% by weight): ##EQU2##
Claim 4
Independent Claim
167 words
A method of reducing the oxygen content of a ceramic powder material prior to molding, said method including the step of heating a raw mixed ceramic powder consisting essentially of 0.1 to 5% by weight of alumina, 0.5 to 10% by weight of yttria and silicon nitride as the remainder, in the presence of a non-sintered or a sintered molding of ceramic material, said molding formed of a compound selected from the group consisting of aluminum nitride, boron nitride, titanium nitride, silicon nitride and aluminum oxide, and having a porosity of at least 10% to a temperature ranging between 1,400° C. and 1,900° C., and whereby the resulting heated mass contains 0.05 to 2.5% by weight of aluminum, and 0.4 to 8.0% by weight of yttrium; and the total oxygen content W O (% by weight) as measured by activation analysis satisfies the following formula denoting the relationship between the aluminum content W A (% by weight) and the yttrium content W Y (% by weight): ##EQU2##
References Cited (Backward Citations)
GB970639A
Cited
US3969125A
Cited
US3992497A
Cited
US3830652A
Cited
US4046580A
Cited
US4071371A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-17 | 1985-02-16 | 1985-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-17 | 1989-02-16 | 1989-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-17 | 1993-02-16 | 1993-08-18 | $7700.00 | Window Closed / Lapsed |