US4769350A
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Silicon nitride sintered material for cutting tools and process for making the same
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1987-09-30
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Granted: 1988-09-06
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Expires: 2007-09-30
Abstract
Abstract A silicon nitride sintered material for cutting tools comprising from about 3 to 10 wt % of partially stablized zirconium oxide, from about 1 to 5 wt % of aluminum oxide, and from about 1 to 10 wt % of yttrium oxide, the balance being silicon nitride, and the process for making the same.
Inventors
- 👤 Takao Nishioka
- 👤 Akira Yamakawa
- 👤 Masaya Miyake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:10
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
46 words
A silicon nitride sintered material for cutting tools consisting essentially of from about 3 to 10 wt% of partially stablized zirconium oxide, from about 1 to 5 wt% of aluminum oxide, and from about 1 to 10 wt% of yttrium oxide, the balance being silicon nitride.
Claim 2
Dependent Claim
46 words
A silicon nitride sintered material for cutting tools consisting essentially of from about 3 to 10 wt% of partially stablized zirconium oxide, from about 1 to 5 wt% of aluminum oxide, and from about 1 to 10 wt% of yttrium oxide, the balance being silicon nitride.
Claim 3
Dependent Claim
73 words
A process for making a silicon nitride sintered material for cutting tools comprising the steps of: (a) mixing from about 3 to 10 wt% of partially stabilized zirconium oxide powder, from about 1 to 5 wt% of aluminum oxide powder, from about 1 to 10 wt% of yttrium oxide powder, and the balance of silicon nitride powder; (b) and sintering the mixture in a non-oxidative gas atmosphere at about 1,600° to 1,900° C.
Claim 4
Dependent Claim
73 words
A process for making a silicon nitride sintered material for cutting tools comprising the steps of: (a) mixing from about 3 to 10 wt% of partially stabilized zirconium oxide powder, from about 1 to 5 wt% of aluminum oxide powder, from about 1 to 10 wt% of yttrium oxide powder, and the balance of silicon nitride powder; (b) and sintering the mixture in a non-oxidative gas atmosphere at about 1,600° to 1,900° C.
Claim 5
Dependent Claim
43 words
A process for making a silicon nitride sintered material for cutting tools as claimed in claim 2, wherein said mixture is hot isostatically pressed in an atmosphere of nitrogen, argon, or a combination thereof at a pressure of about 10 to 2,000 atm.
Claim 6
Dependent Claim
30 words
A process for making a silicon nitride sintered material for cutting tools as claimed in claim 2, wherein said silicon nitride powder contains at least about 40% of β-phase crystals.
Claim 7
Dependent Claim
35 words
A process for making a silicon nitride sintered material for cutting tools as claimed in claim 2, wherein said partially stabilized zirconium oxide powder is partially stabilized with an oxide of yttrium, calcium, or magnesium.
Claim 8
Dependent Claim
30 words
A process for making a silicon nitride sintered material for cutting tools as claimed in claim 5, wherein said partially stabilized zirconium oxide powder is partially stabilized with yttrium oxide.
Claim 9
Dependent Claim
33 words
A process for making a silicon nitride sintered material for cutting tools as claimed in claim 2, wherein the mean particle size of said silicon nitride powder is less than about 0.5 μm.
Claim 10
Dependent Claim
85 words
A silicon nitride sintered material comprising cubic and tetragonal crystals of partially stabilized zirconium oxide in a silicon nitride matrix, produced by a process comprising the steps of (a) mixing from about 3 to 10 wt% of partially stabilized zirconium oxide powder, from about 1 to 5 wt% of aluminum oxide powder, from about 1 to 10 wt% of yttrium oxide powder, and the balance being silicon nitride powder; and (b) sintering the mixture in a non-oxidative gas atmosphere at about 1,600° to 1,900° C.
Claim 11
Dependent Claim
85 words
A silicon nitride sintered material comprising cubic and tetragonal crystals of partially stabilized zirconium oxide in a silicon nitride matrix, produced by a process comprising the steps of (a) mixing from about 3 to 10 wt% of partially stabilized zirconium oxide powder, from about 1 to 5 wt% of aluminum oxide powder, from about 1 to 10 wt% of yttrium oxide powder, and the balance being silicon nitride powder; and (b) sintering the mixture in a non-oxidative gas atmosphere at about 1,600° to 1,900° 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) | 1991-09-06 | 1992-03-07 | 1992-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-06 | 1996-03-07 | 1996-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-06 | 2000-03-07 | 2000-09-06 | $7700.00 | Window Closed / Lapsed |