US4753903A
Expired / Lapsed
US
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Silicon carbide sintered body and a manufacturing method therefor
Assignee: Kyocera Corp
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Filing: 1986-03-27
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Granted: 1988-06-28
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Expires: 2006-03-27
Abstract
Abstract A silicon carbide sintered body suitable for electrical discharge machining and a method for its manufacture are disclosed. The silicon carbide sintered body comprises 0.5-5% by weight of AlN, 0.5-3% by weight (as Ti) of a Ti compound, 0.5-8% by weight of C, 0-3% by weight (as B) of B or a B compound, and a remainder of substantially SiC. It has a volume resistivity at room temperature of not greater than 10 ohm-cm and a density of at least 90% of the theoretical density of SiC. The manufacturing method comprises shaping a mixture of the raw materials and sintering the shaped green body in a non-oxidizing atmosphere at a temperature of 2000 DEG -2300 DEG C.
Inventors
- 👤 Akira Saito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:29
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
85 words
A silicon carbide sintered body consisting essentially of: 0.5-5% by weight of AlN; 0.5-3% by weight (as Ti) of a titanium compound; 0.5-8% by weight of free carbon; 0--3% by weight (as B) of at least one material selected from the group consisting of elemental boron and a boron compound; and a remainder of substantially SiC, said sintered body having a volume resistivity at room temperature of not greater than 10 ohm-cm and a density of at least 90% of the theoretical density of SiC.
Claim 2
Dependent Claim
85 words
A silicon carbide sintered body consisting essentially of: 0.5-5% by weight of AlN; 0.5-3% by weight (as Ti) of a titanium compound; 0.5-8% by weight of free carbon; 0--3% by weight (as B) of at least one material selected from the group consisting of elemental boron and a boron compound; and a remainder of substantially SiC, said sintered body having a volume resistivity at room temperature of not greater than 10 ohm-cm and a density of at least 90% of the theoretical density of SiC.
Claim 3
Dependent Claim
85 words
A silicon carbide sintered body, consisting essentially of: 1-3% by weight of AlN; 1-2% by weight (as Ti) of a titanium compound; 2-5% by weight of free carbon; 0-1% by weight (as B) of at least one material selected from the group consisting of elemental boron and a boron compound; and a remainder of substantially SiC, said sintered body having a volume resistivity at room temperature of not greater than 10 ohm-cm and a density of at least 90% of the theoretical density of SiC.
Claim 4
Dependent Claim
85 words
A silicon carbide sintered body, consisting essentially of: 1-3% by weight of AlN; 1-2% by weight (as Ti) of a titanium compound; 2-5% by weight of free carbon; 0-1% by weight (as B) of at least one material selected from the group consisting of elemental boron and a boron compound; and a remainder of substantially SiC, said sintered body having a volume resistivity at room temperature of not greater than 10 ohm-cm and a density of at least 90% of the theoretical density of SiC.
Claim 5
Dependent Claim
19 words
The silicon carbide sintered body claimed in claim 1, wherein the volume resistivity is not greater than 1 ohm-cm.
Claim 6
Dependent Claim
19 words
The silicon carbide sintered body claimed in claim 2, wherein the volume resistivity is not greater than 1 ohm-cm.
Claim 7
Independent Claim
140 words
A method for manufacturing a silicon carbide sintered body having a volume resistivity at room temperature of not greater than 10 ohm-cm and a density of at least 90% of the theoretical density of SiC, comprising the steps of: (a) shaping a mixture consisting essentially of 0.5-5% by weight of AlN, 0.5-3% by weight (as Ti) of a titanium compound, at least one material selected from the group consisting of free carbon and carbonizable organic substances in an amount sufficient to provide 0.5-8% by weight of free carbon after sintering, 0.3% by weight of at least one material selected from the group consisting of elemental boron and a boron compound, and a remainder of substantially SiC, so as to form a shaped green body; and (b) sintering the shaped body in a non-oxidizing atmosphere at a temperature of 2000°-2300° C.
Claim 8
Independent Claim
140 words
A method for manufacturing a silicon carbide sintered body having a volume resistivity at room temperature of not greater than 10 ohm-cm and a density of at least 90% of the theoretical density of SiC, comprising the steps of: (a) shaping a mixture consisting essentially of 0.5-5% by weight of AlN, 0.5-3% by weight (as Ti) of a titanium compound, at least one material selected from the group consisting of free carbon and carbonizable organic substances in an amount sufficient to provide 0.5-8% by weight of free carbon after sintering, 0.3% by weight of at least one material selected from the group consisting of elemental boron and a boron compound, and a remainder of substantially SiC, so as to form a shaped green body; and (b) sintering the shaped body in a non-oxidizing atmosphere at a temperature of 2000°-2300° C.
Claim 9
Dependent Claim
85 words
A method as claimed in claim 5, wherein said mixture consists essentially of: 1-3% by weight of AlN, 1-2% by weight (as Ti) of a titanium compound, at least one material selected from the group consisting of free carbon and carbonizable organic substances in an amount sufficient to provide 2-5% by weight of free carbon after sintering, 0-1% by weight (as B) of at least one material selected from the group consisting of elemental boron and a boron compound, and a remainder of substantially SiC.
Claim 10
Dependent Claim
17 words
A method as claimed in claim 5, wherein said sintering is carried out under substantially pressureless conditions.
Claim 11
Dependent Claim
17 words
A method as claimed in claim 6, wherein said sintering is carried out under substantially pressureless conditions.
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) | 1991-06-28 | 1991-12-28 | 1992-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-28 | 1995-12-28 | 1996-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-28 | 1999-12-28 | 2000-06-28 | $7700.00 | Window Closed / Lapsed |