Patent US4977112A successfully refreshed from Google Patents.
US4977112A
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Silicon nitride sintered body and a method of producing the same
Assignee: NGK Insulators Ltd
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Filing: 1989-08-16
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Granted: 1990-12-11
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Expires: 2009-08-16
Abstract
Abstract A high density silicon nitride sintered body having a substantially crystallized intergranular phase and an improved mechanical strength at high temperature is produced by firing a molded body of a blend comprising Si3N4, a sintering aid and a crystallization controlling agent selected from at least one compound of Cr, Mn, Co, Ni, Nb and Mo with a specified blending ratio.
Inventors
- 👤 Minoru Matsui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:48
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/5935
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
127 words
A silicon nitride sintered body consisting essentially of: Si 3 N 4 in an amount of 75-95% by weight; at least one crystallization control agent selected from the compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 and MoO 3 ; and a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 1-10% by weight. wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 2
Dependent Claim
127 words
A silicon nitride sintered body consisting essentially of: Si 3 N 4 in an amount of 75-95% by weight; at least one crystallization control agent selected from the compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 and MoO 3 ; and a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 1-10% by weight. wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 3
Dependent Claim
21 words
A silicon nitride sintered body according to claim 1, wherein said silicon nitride is primarily β- Si 3 N 4 .
Claim 4
Dependent Claim
131 words
A silicon nitride sintered body consisting essentially of: Si 3 N 4 in an amount of 75-95% by weight; at least one crystallization control agent selected from the compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 , and MoO 3 ; and a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 , MgO, and CeO 2 ; wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 5
Dependent Claim
131 words
A silicon nitride sintered body consisting essentially of: Si 3 N 4 in an amount of 75-95% by weight; at least one crystallization control agent selected from the compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 , and MoO 3 ; and a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 , MgO, and CeO 2 ; wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 6
Dependent Claim
21 words
A silicon nitride sintered body according to claim 3, wherein said silicon nitride is primarily β- Si 3 N 4 .
Claim 7
Independent Claim
179 words
A method of producing a silicon nitride sintered body comprising: molding a blended powder of Si 3 N 4 which is present in an amount of 75-95% by weight, with at least one crystallization control agent selected from compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 , and MoO 3 , with a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 and 1-10% by weight MgO; heating said molded powder by a process selected from the group consisting of atmospheric pressure heating and pressurized heating; and cooling said heated body at a cooling rate of not greater than 10° C./min from 1500° C.-1000° C.; wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride sintered body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 8
Independent Claim
179 words
A method of producing a silicon nitride sintered body comprising: molding a blended powder of Si 3 N 4 which is present in an amount of 75-95% by weight, with at least one crystallization control agent selected from compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 , and MoO 3 , with a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 and 1-10% by weight MgO; heating said molded powder by a process selected from the group consisting of atmospheric pressure heating and pressurized heating; and cooling said heated body at a cooling rate of not greater than 10° C./min from 1500° C.-1000° C.; wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride sintered body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 9
Dependent Claim
31 words
A method of producing a silicon nitride sintered body according to claim 5, wherein said heating is performed in an atmosphere selected from the group consisting of nitrogen and inert gases.
Claim 10
Dependent Claim
25 words
A method of producing a silicon nitride sintered body according to claim 5, wherein said heating is performed at a temperature of about 1650°-1800° C.
Claim 11
Independent Claim
186 words
A method of producing a silicon nitride sintered body comprising: molding a blended powder of Si 3 N 4 which is present in an amount of 75-95% by weight, with at least one crystallization control agent selected from compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 , and MoO 3 , with a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 , 1-10% by weight MgO and 1-10% by weight CeO 2 ; heating said molded powder by a process selected from the group consisting of atmospheric pressure heating and pressurized heating; and cooling said heated body at a cooling rate of not greater than 10° C./min from 1500° C.-1000° C.; wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride sintered body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 12
Independent Claim
186 words
A method of producing a silicon nitride sintered body comprising: molding a blended powder of Si 3 N 4 which is present in an amount of 75-95% by weight, with at least one crystallization control agent selected from compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 , and MoO 3 , with a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 , 1-10% by weight MgO and 1-10% by weight CeO 2 ; heating said molded powder by a process selected from the group consisting of atmospheric pressure heating and pressurized heating; and cooling said heated body at a cooling rate of not greater than 10° C./min from 1500° C.-1000° C.; wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride sintered body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 13
Dependent Claim
31 words
A method of producing a silicon nitride sintered body according to claim 8, wherein said heating is performed in an atmosphere selected from the group consisting of nitrogen and inert gases.
Claim 14
Dependent Claim
25 words
A method of producing a silicon nitride sintered body according to claim 8, wherein said heating is performed at a temperature of about 1650°-1800° C.
Claim 15
Independent Claim
193 words
A method of producing a silicon nitride sintered body comprising: molding a blended powder of Si 3 N 4 which is present in an amount of 75-95% by weight, with at least one crystallization control agent selected from compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 , and MoO 3 , with a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 , 1-10% by weight MgO and 1-10% by weight CeO 2 ; heating said molded powder at a temperature of about 1650°-1800° C. by a process selected from the group consisting of atmospheric pressure heating and pressurized heating; and cooling said heated body at a cooling rate of not greater than 10° C./min from 1,500° C.-1,000° C.; wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride sintered body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 16
Independent Claim
193 words
A method of producing a silicon nitride sintered body comprising: molding a blended powder of Si 3 N 4 which is present in an amount of 75-95% by weight, with at least one crystallization control agent selected from compounds of the group consisting of Mn, Co, Ni, Nb, and Mo, said crystallization control agent being present in an amount of 0.05-3.0% by weight as MnO, CoO, NiO, Nb 2 O 5 , and MoO 3 , with a remainder being a sintering aid present as 2-15% by weight Y 2 O 3 , 1-10% by weight MgO and 1-10% by weight CeO 2 ; heating said molded powder at a temperature of about 1650°-1800° C. by a process selected from the group consisting of atmospheric pressure heating and pressurized heating; and cooling said heated body at a cooling rate of not greater than 10° C./min from 1,500° C.-1,000° C.; wherein said crystallization control agent results in a substantially crystallized intergranular phase in said silicon nitride sintered body, such that a bending strength of said body at about 1000° C. is substantially the same as a bending strength of said body at room temperature.
Claim 17
Dependent Claim
31 words
A method of producing a silicon nitride sintered body according to claim 11, wherein said heating is performed in an atmosphere selected from the group consisting of nitrogen and inert gases.
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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) | 1993-12-10 | 1994-06-11 | 1994-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-10 | 1998-06-11 | 1998-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-10 | 2002-06-11 | 2002-12-11 | $7700.00 | Window Closed / Lapsed |