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US5089449A
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Silicon nitride sintered bodies
Assignee: NGK Insulators Ltd
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Filing: 1990-03-01
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Granted: 1992-02-18
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Expires: 2010-03-01
Abstract
Abstract Silicon nitride sintered bodies including Si 3 N 4 and at least one element selected from Y 2 O 3 , MgO, ZrO 2 . In the silicon nitride bodies, a J phase solid solution is present in an intergranular phase, which satisfies a relation of 0.65x≦y≦x+2 wherein y is an amount of J phase solid solution and x is an amount of Y 2 O 3 as an additive.
Inventors
- 👤 Shinichi Miwa
- 👤 Seiichi Asami
- 👤 Takehiro Kajihara
- 👤 Kouichi Imao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:45
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
77 words
A silicon nitride sintered body consisting essentially of Si 3 N 4 as a main ingredient and about 3-15 wt.% Y 2 O 3 , about 1-7 wt.% MgO and about 0.5-1.00/g wt.% ZrO 2 . comprising an intergranular phase consisting essentially of a J phase solid solution, wherein an amount of J phase solid solution: y, satisfies the following formula with respect to an amount of Y 2 O 3 : x, as an additive; 0.65x≦y≦x+2.
Claim 2
Dependent Claim
77 words
A silicon nitride sintered body consisting essentially of Si 3 N 4 as a main ingredient and about 3-15 wt.% Y 2 O 3 , about 1-7 wt.% MgO and about 0.5-1.00/g wt.% ZrO 2 . comprising an intergranular phase consisting essentially of a J phase solid solution, wherein an amount of J phase solid solution: y, satisfies the following formula with respect to an amount of Y 2 O 3 : x, as an additive; 0.65x≦y≦x+2.
Claim 3
Dependent Claim
27 words
A silicon nitride sintered body according to claim 1, wherein a part of Y 2 O 3 is substituted by an oxide of a rare earth element.
Claim 4
Dependent Claim
107 words
A silicon nitride sintered body according to claim 1, wherein said J phase solid solution has a crystal phase having a caspidine structure of a monoclinic system represented by the formula: M 3 I (M 2 II M 7 III )M I M IV 2 , wherein M I is an element selected from the group consisting of Y, Mg, Fe and Ni; M II is an element selected from the group consisting of Si and Al; M III is an element selected from the group consisting of O and N; and M IV is an element selected from the group consisting of F, O and N.
Claim 5
Dependent Claim
28 words
The silicon nitride sintered body of claim 1, wherein said sintered body has a strength of about 630-800 MPa while being maintained at 800° C. for 1,000 hours.
Claim 6
Dependent Claim
27 words
The silicon nitride sintered body of claim 1, wherein said sintered body has a strength of about 600-760 MPa while being maintained at 900° for 1,000 hours.
Claim 7
Dependent Claim
22 words
The silicon nitride sintered body of claim 1, wherein said sintered body has a strength of about 730-920 MPa at room temperature.
Claim 8
Dependent Claim
22 words
The silicon nitride sintered body of claim 1, wherein said sintered body has a strength of about 620-850 MPa at 1200° C.
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) | 1995-02-17 | 1995-08-19 | 1996-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-17 | 1999-08-19 | 2000-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-17 | 2003-08-19 | 2004-02-18 | $7700.00 | Window Closed / Lapsed |