US4988646A
Expired / Lapsed
US
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Method for producing a ceramic
Assignee: International Business Machines Corp
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Filing: 1989-07-27
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Granted: 1991-01-29
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Expires: 2009-07-27
Abstract
Abstract A nitride, preferably AlN, ceramic is produced by contacting a mixed oxide gel (produced from organometallic/inorganic metal salt precursors) which, during sintering steps, transform into a melt that forms low contact angle with the nitride powder. The composition is sintered to thereby produce the desired ceramic.
Inventors
- 👤 Shyama P. Mukherjee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:26
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/581; C04B35/584; C04B35/593
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
101 words
A method for producing an aluminum nitride ceramic which comprises: (a) obtaining a powder of aluminum nitride; (b) contacting said powder with gel of a metallic compound that forms a low contact angle with said powder at the sintering step (d) and wherein said metallic compound include a member selected from the group of cobalt, nickel and mixtures thereof and at least one alloying member selected from the group of transition elements and rare earth elements; removing solvents and any organic material obtained from the composition from step (b); (d) sintering the composition from step (c) to thereby produce said ceramics.
Claim 2
Independent Claim
101 words
A method for producing an aluminum nitride ceramic which comprises: (a) obtaining a powder of aluminum nitride; (b) contacting said powder with gel of a metallic compound that forms a low contact angle with said powder at the sintering step (d) and wherein said metallic compound include a member selected from the group of cobalt, nickel and mixtures thereof and at least one alloying member selected from the group of transition elements and rare earth elements; removing solvents and any organic material obtained from the composition from step (b); (d) sintering the composition from step (c) to thereby produce said ceramics.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said powder has a particle size of about 1 μ to about 12 μ.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein the average particle size of said powder is about 2 microns.
Claim 5
Dependent Claim
31 words
The method of claim 1 wherein the metallic compound produced from the gel layer forms a contact angle of about 0° to about 40° with said powder at the sintering step.
Claim 6
Dependent Claim
28 words
The method of claim 1 wherein said gel is applied as a coating to said powder or was intimately mixed as a second phase in the composite powder.
Claim 7
Dependent Claim
30 words
The method of claim 1 wherein said powder is dispersed in a non-aqueous medium containing organo-metallic compound capable of forming a gel and then converting the dispersion into a gel.
Claim 8
Dependent Claim
25 words
The method of claim 1 wherein said powder comprises at least about 90% by weight of the combined solids from said powder and metallic compound.
Claim 9
Dependent Claim
26 words
The method of claim 1 wherein said powder comprises about 90% to about 99.5% by weight of the combined solids from said powder and metallic compound.
Claim 10
Dependent Claim
30 words
The method of claim 1 wherein said metallic compound is an alloy of nickel and an alloying metal selected from the group of yttrium, lanthanum, Sc, Ce, hafnium, zirconium, titanium.
Claim 11
Dependent Claim
28 words
The method of claim 9 wherein said alloy contains about 90% to about 30% of nickel and about 10% to about 70% by weight of said alloying metal.
Claim 12
Dependent Claim
16 words
The method of claim 9 wherein said metallic compound is an alloy of nickel and yttrium.
Claim 13
Dependent Claim
21 words
The method of claim 1 wherein said sintering is carried out at temperatures of about 1500° C. to about 1900° C.
Claim 14
Dependent Claim
15 words
The method of claim 1 wherein said sintering is carried out under a reducing atmosphere.
Claim 15
Dependent Claim
16 words
The method of claim 1 wherein said sintering is carried out in the presence of ammonia.
Claim 16
Dependent Claim
12 words
The method of claim 1 wherein said sintering is a pressureless sintering.
Claim 17
Dependent Claim
18 words
The method of claim 1 wherein said sintering is completed in about 1/2 hour to about 2 hours.
Claim 18
Dependent Claim
11 words
The method of claim 1 wherein said sintering is hot pressing.
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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) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |