US4179301A
Expired / Lapsed
US
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Si3 N4 containing intergranular phase nucleating agent and method
Assignee: GTE Sylvania Inc
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Filing: 1979-01-08
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Granted: 1979-12-18
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Expires: 1999-01-08
Abstract
Abstract Polycrystalline ceramic bodies of Si 3 N 4 when prepared with a nucleating agent to obtain an intergranular phase which is substantially crystalline, exhibit improved mechanical strength at elevated temperatures over bodies having a glass-containing intergranular phase.
Inventors
- 👤 Sergej-Tomislav Buljan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:31
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
77 words
A polycrystalline ceramic body consisting essentially of a first phase of Si 3 N 4 grains, and a second crystalline intergranular phase comprising SiO 2 and at least one densifying additive, characterized in that the body additionally contains from 100 to 1,000 parts per million of at least one nucleating agent selected from the group consisting of Ti, Fe, and the oxides and nitrides of Ti and Fe to facilitate substantially complete crystallization of the intergranular phase.
Claim 2
Dependent Claim
77 words
A polycrystalline ceramic body consisting essentially of a first phase of Si 3 N 4 grains, and a second crystalline intergranular phase comprising SiO 2 and at least one densifying additive, characterized in that the body additionally contains from 100 to 1,000 parts per million of at least one nucleating agent selected from the group consisting of Ti, Fe, and the oxides and nitrides of Ti and Fe to facilitate substantially complete crystallization of the intergranular phase.
Claim 3
Dependent Claim
19 words
The body of claim 1 wherein the body contains at least 200 parts per million of the nucleating agent.
Claim 4
Dependent Claim
46 words
The body of claim 1 wherein the densifying additive is selected from the group consisting of Al 2 O 3 , MgO, Y 2 O 3 , La 2 O 3 , HfO 2 , SiO 2 , CeO 2 , CrN, ZrO 2 and ZrN.
Claim 5
Dependent Claim
28 words
The body of claim 3 wherein the densifying additive is selected from the group consisting of Al 2 O 3 , MgO and Y 2 O 3 .
Claim 6
Dependent Claim
22 words
The body of claim 4 wherein Al 2 O 3 is present in the amount of up to about 4 weight percent.
Claim 7
Dependent Claim
19 words
The body of claim 5 wherein MgO is present in the amount of up to about 5 weight percent.
Claim 8
Dependent Claim
22 words
The body of claim 5 wherein Y 2 O 3 is present in the amount of up to about 20 weight percent.
Claim 9
Independent Claim
99 words
A method for producing a polycrystalline body consisting essentially of a first phase of Si 3 N 4 grains and a second crystalline intergranular phase comprising SiO 2 and at least one densifying additive, the method comprising consolidating particulate starting materials and sintering the consolidated materials, the method characterized by adding at least one nucleating agent selected from the group consisting of Ti, Fe, and the oxides and nitrides of Ti and Fe in the amount of about 100 to 1,000 parts per million to the materials prior to consolidation to facilitate substantially complete crystallization of the intergranular phase.
Claim 10
Independent Claim
99 words
A method for producing a polycrystalline body consisting essentially of a first phase of Si 3 N 4 grains and a second crystalline intergranular phase comprising SiO 2 and at least one densifying additive, the method comprising consolidating particulate starting materials and sintering the consolidated materials, the method characterized by adding at least one nucleating agent selected from the group consisting of Ti, Fe, and the oxides and nitrides of Ti and Fe in the amount of about 100 to 1,000 parts per million to the materials prior to consolidation to facilitate substantially complete crystallization of the intergranular phase.
Claim 11
Dependent Claim
22 words
The method of claim 8 wherein the nucleating agent is added in the amount of at least about 200 parts per million.
Claim 12
Dependent Claim
46 words
The method of claim 8 wherein the densifying additive is selected from the group consisting of Al 2 O 3 , MgO, Y 2 O 3 , La 2 O 3 , CeO 2 , HfO 2 , SiO 2 , CrN, ZrO 2 and ZrN.
Claim 13
Dependent Claim
28 words
The method of claim 10 wherein the densifying additive is selected from the group consisting of Al 2 O 3 , MgO and Y 2 O 3 .
Claim 14
Dependent Claim
22 words
The method of claim 11 wherein Al 2 O 3 is present in the amount of up to about 4 weight percent.
Claim 15
Dependent Claim
19 words
The method of claim 12 wherein MgO is present in the amount of up to about 5 weight percent.
Claim 16
Dependent Claim
22 words
The method of claim 12 wherein Y 2 O 3 is present in the amount of up to about 20 weight percent.
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) | 1982-12-17 | 1983-06-18 | 1983-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-17 | 1987-06-18 | 1987-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-17 | 1991-06-18 | 1991-12-18 | $7700.00 | Window Closed / Lapsed |