US5122485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sintered silicon carbide and silicon nitride base composite
Assignee: Nissan Motor Co Ltd
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Filing: 1991-01-23
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Granted: 1992-06-16
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Expires: 2011-01-23
Abstract
Abstract A method for producing a sintered silicon carbide and silicon nitride base composite which is suitable for a material for automotive engine parts. The method is comprised of compacting a mixture including, as major components, powder of β-type silicon carbide and powder of α-type silicon nitride to form a compact. The compact is first sintered at ordinary pressure, and then resintered at a pressure of nitrogen gas ranging from 10 to 2000 atmosphere and at a temperature higher 100° to 200° C. than that in the ordinary pressure sintering, thereby obtaining the sintered composite high in strength and toughness.
Inventors
- 👤 Yoshio Akimune
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:17
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/5935
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
86 words
A method for producing a sintered silicon carbide and silicon nitride composite, comprising the following steps in the sequence set forth: sintering a mixture including, as major components, a powder of β-type silicon carbide and a powder of α-type silicon nitride at one atmosphere pressure of nitrogen and at a first sintering temperature; and resintering the sintered mixture at a pressure of nitrogen gas ranging from 10 to 2000 atmosphere and at a second sintering temperature 100° to 200° C. higher than said first sintering temperature.
Claim 2
Independent Claim
86 words
A method for producing a sintered silicon carbide and silicon nitride composite, comprising the following steps in the sequence set forth: sintering a mixture including, as major components, a powder of β-type silicon carbide and a powder of α-type silicon nitride at one atmosphere pressure of nitrogen and at a first sintering temperature; and resintering the sintered mixture at a pressure of nitrogen gas ranging from 10 to 2000 atmosphere and at a second sintering temperature 100° to 200° C. higher than said first sintering temperature.
Claim 3
Independent Claim
93 words
A method for producing a sintered silicon carbide and silicon nitride composite, comprising the following steps in the sequence set forth: compacting a mixture including, as major components, powder of β-type silicon carbide and powder of α-type silicon nitride to form a compact; sintering the compact at one atmosphere pressure and at a first sintering temperature to form a sintered compact; resintering the sintered compact at a pressure of nitrogen gas ranging from 10 to 2000 atmosphere and at a second sintering temperature 100° to 200° C. higher than said first sintering temperature.
Claim 4
Independent Claim
93 words
A method for producing a sintered silicon carbide and silicon nitride composite, comprising the following steps in the sequence set forth: compacting a mixture including, as major components, powder of β-type silicon carbide and powder of α-type silicon nitride to form a compact; sintering the compact at one atmosphere pressure and at a first sintering temperature to form a sintered compact; resintering the sintered compact at a pressure of nitrogen gas ranging from 10 to 2000 atmosphere and at a second sintering temperature 100° to 200° C. higher than said first sintering temperature.
Claim 5
Dependent Claim
16 words
A method as claimed in claim 2, wherein said second sintering temperature is about 1750° C.
Claim 6
Dependent Claim
23 words
A method as claimed in claim 2, wherein said second sintering temperature is within a range from about 1850° to about 1950° C.
Claim 7
Dependent Claim
25 words
A method as claimed in claim 2, wherein said sintering is carried out in an atmosphere of nitrogen gas at a pressure of 1 atmosphere.
Claim 8
Independent Claim
95 words
A method for producing a sintered silicon carbide and silicon nitride composite, comprising the following steps in the sequence set forth: sintering a mixture including, as major components, a powder of β-type silicon carbide having an average particle size ranging from 0.2 to 0.5 μm, and a powder of α-type silicon nitride at one atmospheric pressure and at a first sintering temperature; and resintering the sintered mixture at a pressure of nitrogen gas ranging from 10 to 2000 atmosphere and at a second sintering temperature 100° to 200° C. higher than said first sintering temperature.
Claim 9
Independent Claim
95 words
A method for producing a sintered silicon carbide and silicon nitride composite, comprising the following steps in the sequence set forth: sintering a mixture including, as major components, a powder of β-type silicon carbide having an average particle size ranging from 0.2 to 0.5 μm, and a powder of α-type silicon nitride at one atmospheric pressure and at a first sintering temperature; and resintering the sintered mixture at a pressure of nitrogen gas ranging from 10 to 2000 atmosphere and at a second sintering temperature 100° to 200° C. higher than said first sintering temperature.
Claim 10
Dependent Claim
17 words
The process of claim 6 wherein the silicon carbide has an average particle size of 0.3 μm.
Claim 11
Dependent Claim
14 words
The process of claim 7 wherein said first sintering temperature is about 1750° C.
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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) | 1995-06-16 | 1995-12-16 | 1996-06-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-16 | 1999-12-16 | 2000-06-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-16 | 2003-12-16 | 2004-06-16 | $7700.00 | Window Closed / Lapsed |