US4376652A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High density high strength Si3 N4 ceramics prepared by pressureless sintering of amorphous Si3 N4 powder and Ti
Assignee: Clinical Product Development Ltd
•
Filing: 1979-01-08
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Granted: 1983-03-15
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Expires: 1999-01-08
Abstract
Abstract High purity fine particle size amorphous Si 3 N 4 powder compacts may be pressureless sintered to high density by the addition of from 100 to 1000 parts per million Ti to the powder prior to compaction.
Inventors
- 👤 Sergej-Tomislav Buljan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:26
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
38 words
A powder mixture consisting essentially of amorphous Si 3 N 4 powder of average particle size below about 3 microns characterized in that the Si 3 N 4 powder contains about 100 to 1000 parts per million Ti.
Claim 2
Dependent Claim
38 words
A powder mixture consisting essentially of amorphous Si 3 N 4 powder of average particle size below about 3 microns characterized in that the Si 3 N 4 powder contains about 100 to 1000 parts per million Ti.
Claim 3
Dependent Claim
36 words
The powder mixture of claim 1 in which the Si 3 N 4 , powder consists of up to 5 weight percent crystalline Si 3 N 4 , remainder substantially amorphous Si 3 N 4 .
Claim 4
Dependent Claim
54 words
The powder mixture of claim 1 additionally containing up to 25 weight percent of at least one additive selected from the group consisting of MgO, CrN, Y 2 O 3 , HfO 2 , ZrO 2 , ZrN, La 2 O 3 , CeO 2 , SiO 2 and Al 2 O 3 .
Claim 5
Dependent Claim
12 words
A powder compact of the powder of claims 1, 2 or 3.
Claim 6
Dependent Claim
13 words
The powder compact of claim 4 in which a volatilizable additive is present.
Claim 7
Dependent Claim
19 words
A polycrystalline body of Si 3 N 4 obtained by the pressureless sintering of the compact of claim 4.
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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) | 1986-03-14 | 1986-09-13 | 1987-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-14 | 1990-09-13 | 1991-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-14 | 1994-09-13 | 1995-03-15 | $7700.00 | Window Closed / Lapsed |