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US4983422A
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Process for forming aluminum oxide ceramic composites
Assignee: Kaiser Aerotech Inc
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Filing: 1988-03-11
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Granted: 1991-01-08
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Expires: 2008-03-11
Abstract
Abstract Aluminum oxide ceramic composite articles having high flexural and tensile strength are produced by introducing a liquid aluminum oxide precursor material into a ceramic reinforcement fabric, curing the precursor material at an elevated temperature, and converting the cured precursor material to an aluminum oxide ceramic by pyrolysis at temperatures which do not result in the degradation of the reinforcement material. Such ceramic composite articles are particularly useful for applications requiring a low dielectric constant and a high mechanical strength.
Inventors
- 👤 H. O. Davis
- 👤 Marvin Pennell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:25
CPC Classifications
B; B32; B32B; B32B18/00; C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/117; C04B35/622; C04B35/626; C04B35/62605; C04B35/62625; C04B35/6263; C04B35/6264; C04B35/6269; C04B35/628; C04B35/62844; C04B35/62847; C04B35/62849; C04B35/62852; C04B35/62857; C04B35/6286; C04B35/62863; C04B35/62865; C04B35/62868; C04B35/62873; C04B35/62897; C04B35/71; C04B35/78; C04B35/80; C04B2235/00; C04B2235/02; C04B2235/50; C04B2235/52; C04B2235/5208; C04B2235/5216; C04B2235/522; C04B2235/5224; C04B2235/5252; C04B2235/60; C04B2235/616; C04B2235/65; C04B2235/656; C04B2235/6562; C04B2235/6565; C04B2235/6567; C04B2235/70; C04B2235/74; C04B2235/77; C04B2235/96; C04B2237/00; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/343; C04B2237/38
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
71 words
A process for forming aluminum oxide ceramic composites, said process comprising: introducing a liquid aluminum oxide precursor material into a reinforcement fabric substrate wherein said liquid aluminum oxide precursor is ionic aluminum suspended in a n aqueous alcohol solution in the presence of a mineral acid; curing the aluminum oxide precursor; and converting the cured aluminum oxide precursor material to an aluminum oxide ceramic phase by oxidation at an elevated temperature.
Claim 2
Dependent Claim
71 words
A process for forming aluminum oxide ceramic composites, said process comprising: introducing a liquid aluminum oxide precursor material into a reinforcement fabric substrate wherein said liquid aluminum oxide precursor is ionic aluminum suspended in a n aqueous alcohol solution in the presence of a mineral acid; curing the aluminum oxide precursor; and converting the cured aluminum oxide precursor material to an aluminum oxide ceramic phase by oxidation at an elevated temperature.
Claim 3
Dependent Claim
18 words
A process as in claim 1, wherein the liquid aluminum oxide precursor has a viscosity below 250 cp.
Claim 4
Dependent Claim
17 words
A process as in claim 1, wherein the aqueous alcohol solution is an aqueous dihydric alcohol solution.
Claim 5
Dependent Claim
13 words
A process as in claim 3, wherein the dihydric polyol is ethylene glycol.
Claim 6
Dependent Claim
38 words
A process as in claim 1, wherein the liquid aluminum precursor is cured at a temperature in the range from about 125° to 200° C. for a time period in the range from about 1 to 3 hours.
Claim 7
Dependent Claim
29 words
A process as in claim 1, wherein the pyrolysis step includes a stepped increase in temperature to a final temperature in the range from about 850° to 950° C.
Claim 8
Dependent Claim
107 words
A process for forming aluminum oxide ceramic composites, said process comprising: (a) forming a refractory interface layer on a reinforcement fabric; (b) introducing a liquid aluminum oxide precursor material onto the reinforcement fabric over the refractory interface layer, wherein said liquid aluminum oxide precursor is ionic aluminum suspended in an aqueous alcohol solution in the presence of a mineral acid; (c) curing the liquid aluminum oxide precursor material at an elevated temperature; (d) converting the cured liquid aluminum oxide precursor material to a ceramic by oxidizing under an elevated temperature; and (e) densifying the composite by repeating steps (a) through (d) until a desired density is attained.
Claim 9
Dependent Claim
107 words
A process for forming aluminum oxide ceramic composites, said process comprising: (a) forming a refractory interface layer on a reinforcement fabric; (b) introducing a liquid aluminum oxide precursor material onto the reinforcement fabric over the refractory interface layer, wherein said liquid aluminum oxide precursor is ionic aluminum suspended in an aqueous alcohol solution in the presence of a mineral acid; (c) curing the liquid aluminum oxide precursor material at an elevated temperature; (d) converting the cured liquid aluminum oxide precursor material to a ceramic by oxidizing under an elevated temperature; and (e) densifying the composite by repeating steps (a) through (d) until a desired density is attained.
Claim 10
Dependent Claim
47 words
A process as in claim 7, wherein the refractory interface layer is formed by chemical vapor deposition of a material selected from the group consisting of alumina, carbon, boron nitride, silicon dioxide, and silicon carbide to a thickness in the range from about 0.1 to 3 μm.
Claim 11
Dependent Claim
35 words
A process as in claim 7, wherein the refractory interface layer is formed by applying an organic precursor and pyrolyzing the precursor to form a carbon layer in the range from 0.1 to 3 μm.
Claim 12
Dependent Claim
18 words
A process as in claim 7, wherein the liquid aluminum oxide precursor has a viscosity below 250 cp.
Claim 13
Dependent Claim
17 words
A process as in claim 7, wherein the aqueous alcohol solution is an aqueous dihydric alcohol solution.
Claim 14
Dependent Claim
13 words
A process as in claim 11, wherein the dihydric alcohol is ethylene glycol.
Claim 15
Dependent Claim
39 words
A process as in claim 7, wherein the liquid aluminum oxide precursor is cured at a temperature in the range from about 125° to 200° C. for a time period in the range from about 1 to 3 hours.
Claim 16
Dependent Claim
30 words
A process as in claim 7, wherein the converting step (d) includes a stepped increase in temperature to a final temperature in the range from about 850° to 950° C.
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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) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |