US5049531A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silicon nitride sintered body
Assignee: Niterra Co Ltd
•
Filing: 1989-09-07
•
Granted: 1991-09-17
•
Expires: 2009-09-07
Abstract
Abstract A sintered body of silicon nitride having high strength, toughness and oxidation resistance consists essentially of, by weight percentages, 0.5 to 7.0% of a Mg component calculated as MgO, 0.5 to 7.0% of a Zr component calculated as ZrO 2 , 0.5 to 10.0% of a Ce component calculated as CeO 2 , and the balance being Si 3 N 4 . The sum of Mg, Zr and Ce components calculated as oxides is 3 to 20% by weight. This product is suitable for engine parts or cutting tools.
Inventors
- 👤 Kenji Nakanishi
- 👤 Yo Tajima
- 👤 Masakazu Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:57
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/5935
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
115 words
A sintered body of silicon nitride consisting essentially of, in weight percentages of the body, 0.5 to 7.0% of a Mg component calculated as MgO, 0.5 to 7.0% of a Zr component calculated as ZrO 2 , 0.5 to 10.0% of a Ce component calculated as CeO 2 , and the balance being Si 3 N 4 , said body having a strength of not less than 80 kgf/mm 2 , a fracture toughness of not less than 6 MPa m 1/2 , a relative density of not less than 95% of theoretical density and a weight increase after oxidation testing at 800° C. for 100 hours of no more than 0.3 mg/cm 2 .
Claim 2
Dependent Claim
115 words
A sintered body of silicon nitride consisting essentially of, in weight percentages of the body, 0.5 to 7.0% of a Mg component calculated as MgO, 0.5 to 7.0% of a Zr component calculated as ZrO 2 , 0.5 to 10.0% of a Ce component calculated as CeO 2 , and the balance being Si 3 N 4 , said body having a strength of not less than 80 kgf/mm 2 , a fracture toughness of not less than 6 MPa m 1/2 , a relative density of not less than 95% of theoretical density and a weight increase after oxidation testing at 800° C. for 100 hours of no more than 0.3 mg/cm 2 .
Claim 3
Dependent Claim
35 words
The sintered body of silicon nitride according to claim 1 wherein the sum of Mg, Zr and Ce components calculated as MgO, ZrO 2 and CeO 2 , respectively, is 3 to 20% by weight.
Claim 4
Dependent Claim
77 words
The sintered body of silicon nitride according to claim 2 wherein the Mg, Zr and Ce components are within a range defined by straight lines interconnecting points A, B, C and D on drawing FIG. 1: A (0.6, 0.3, 0.1), B (0.6, 0.1, 0.3), C (0.1, 0.1, 0.8), and D (0.1, 0.8, 0.1) in a ternary triangular coordinate system of MgO, ZrO 2 and CeO 2 , wherein the numbers stand for weight percents of the components.
Claim 5
Dependent Claim
57 words
The sintered body according to claim 1 consisting essentially of 2 to 5% by weight of the Mg component, 2 to 5% by weight of the Zr component and 2 to 8% by weight of the Ce component, the sum of these components being 6 to 15% by weight, each component being calculated as each said oxide.
Claim 6
Dependent Claim
60 words
The sintered body of silicon nitride according to claim 1 consisting essentially of 1 to 5% by weight of the Mg component, 1 to 7% by weight of the Zr component and 1 to 8% by weight of the Ce component, the sum of these components being 3 to 20% by weight, each component being calculated as each said oxide.
Claim 7
Dependent Claim
62 words
The sintered body of silicon nitride according to claim 3 having a strength of not less than 90 kgf/mm 2 , fracture toughness of not less than 6.5 MPa.m 1/2 , a relative density of not less than 96% and a weight increase, when tested, after oxidation testing at 800° C. for 100 hours of not more than 0.3 mg/cm 2 .
Claim 8
Dependent Claim
33 words
The sintered body of silicon nitride according to claim 6 having a weight increase, when tested after oxidation testing at 800° C. for 100 hours of not more than 0.15 mg/cm 2 .
Claim 9
Dependent Claim
19 words
The sintered body of silicon nitride according to claim 6 having a relative density of not less than 99%.
Claim 10
Dependent Claim
22 words
The sintered body of silicon nitride according to claim 6 having the fracture toughness of not less than 7 MPa.m 1/2 .
References Cited (Backward Citations)
DE2800174A1
Cited
US4304576A
Cited
JPS5815371B2
Cited
JPS5771871A
Cited
US4777822A
Cited
JPS57166371A
Cited
JPS5864275A
Cited
JPS57188468A
Cited
EP0117936A1
Cited
US4535063A
Cited
JPS59190271A
Cited
JPS59190272A
Cited
US4560669A
Cited
JPS6065766A
Cited
US4449989A
Cited
JPS60131865A
Cited
JPS61178472A
Cited
US4764490A
Cited
US4692420A
Cited
US4692419A
Cited
US4696778A
Cited
US4871697A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-09-16 | 1995-03-18 | 1995-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-16 | 1999-03-18 | 1999-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-16 | 2003-03-18 | 2003-09-17 | $7700.00 | Window Closed / Lapsed |