US4692419A
Expired / Lapsed
US
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Silicon nitride sintered body and manufacturing method thereof
Assignee: NGK Insulators Ltd
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Filing: 1986-08-04
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Granted: 1987-09-08
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Expires: 2006-08-04
Abstract
Abstract A silicon nitride sintered body essentially consisting of compounds of Sr, Mg, Ce, Zr and Al in amounts of from 0.1 to 18% by weight when calculated as SrO, from 0.2 to 25% by weight when calculated as MgO, from 0.1 to 20% by weight when calculated as CeO 2 , from 0.1 to 15% by weight when calculated as ZrO 2 and from 1 to 20% by weight when calculated as Al 2 O 3 , respectively, and the balance being silicon nitride. A method of manufacturing the silicon nitride sintered body is also disclosed. The silicon nitride sintered body has a low thermal conductivity while high mechanical strength and high fracture toughness being maintained.
Inventors
- 👤 Minoru Matsui
- 👤 Takao Soma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:22
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
91 words
A silicon nitride sintered body consisting essentially of Sr in an amount of from 0.1 to 18% by weight calculated as SrO, Mg in an amount of from 0.2 to 25% by weight calculated as MgO, Ce in an amount of from 0.1 to 20% by weight calculated as CeO 2 , Zr in an amount of from 0.1 to 15% by weight calculated as ZrO 2 and Al in an amount of from 1 to 20% by weight calculated as Al 2 O 3 , the balance being silicon nitride.
Claim 2
Dependent Claim
91 words
A silicon nitride sintered body consisting essentially of Sr in an amount of from 0.1 to 18% by weight calculated as SrO, Mg in an amount of from 0.2 to 25% by weight calculated as MgO, Ce in an amount of from 0.1 to 20% by weight calculated as CeO 2 , Zr in an amount of from 0.1 to 15% by weight calculated as ZrO 2 and Al in an amount of from 1 to 20% by weight calculated as Al 2 O 3 , the balance being silicon nitride.
Claim 3
Dependent Claim
61 words
A silicon nitride sintered body according to claim 1, wherein Sr is present in an amount of from 0.4 to 12% by weight calculated as SrO, Mg is present in an amount of from 0.5 to 17% by weight calculated as MgO, and Ce is present in an amount of from 0.4 to 13% by weight calculated as CeO 2 .
Claim 4
Independent Claim
118 words
A method of manufacturing a silicon nitride sintered body, which comprises formulating and molding a raw material consisting essentially of Sr in an amount of from 0.1 to 18% by weight calculated as SrO, Mg in an amount of from 0.2 to 25% by weight calculated as MgO, Ce in an amount of from 0.1 to 20% by weight calculated as CeO 2 , Zr in an amount of from 0.1 to 15% by weight calculated as ZrO 2 and Al in an amount of from 1 to 20% by weight calculated as Al 2 O 3 , the balance being silicon nitride; and then firing the resulting molding in a nitrogen atmosphere or an inert gas atmosphere.
Claim 5
Independent Claim
118 words
A method of manufacturing a silicon nitride sintered body, which comprises formulating and molding a raw material consisting essentially of Sr in an amount of from 0.1 to 18% by weight calculated as SrO, Mg in an amount of from 0.2 to 25% by weight calculated as MgO, Ce in an amount of from 0.1 to 20% by weight calculated as CeO 2 , Zr in an amount of from 0.1 to 15% by weight calculated as ZrO 2 and Al in an amount of from 1 to 20% by weight calculated as Al 2 O 3 , the balance being silicon nitride; and then firing the resulting molding in a nitrogen atmosphere or an inert gas atmosphere.
Claim 6
Dependent Claim
64 words
A method of manufacturing a silicon nitride sintered body according to claim 3, wherein Sr is present in an amount of from 0.4 to 25% by weight calculated as SrO, Mg is present in an amount of from 0.5 to 17% by weight calculated as MgO, and Ce is present in amount of from 0.4 to 13% by weight calculated as CeO 2 .
Claim 7
Dependent Claim
31 words
A method of manufacturing a silicon nitride sintered body according to claim 3, wherein the Zr is introduced into the raw material through abrasion of a zirconia porcelain media during milling.
Claim 8
Dependent Claim
46 words
A method of manufacturing a silicon nitride sintered body according to claim 5, wherein the zirconia porcelain media have a specific gravity of not less than 5, Mohs hardness of not less than 6 and a ZrO 2 content of not less than 70% by weight.
Claim 9
Dependent Claim
29 words
A method of manufacturing a silicon nitride sintered body according to claim 3, wherein the silicon nitride raw material powder contains not less than 50% by weight of α-phase.
Claim 10
Dependent Claim
62 words
A method of manufacturing a silicon nitride sintered body according to claim 7, wherein the silicon nitride raw material powder has a total content of Fe, Ca, Na and K impurities of not more than 3% by weight, an average particle size of not more than 5 μm and a BET specific surface area of from 1 to 50 m 2 /g.
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) | 1990-09-07 | 1991-03-09 | 1991-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-07 | 1995-03-09 | 1995-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-07 | 1999-03-09 | 1999-09-08 | $7700.00 | Window Closed / Lapsed |