US4605594A
Expired / Lapsed
US
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Ceramic articles having a nonporous core and porous outer layer
Assignee: 3M Co
•
Filing: 1984-08-08
•
Granted: 1986-08-12
•
Expires: 2004-08-08
Abstract
Abstract Fired ceramic article, which exhibits a uniform, porous sheath and a core. The porous sheath or outer layer of the article can be filled with various infiltrates, e.g., catalysts, in order to provide the article with useful properties. The article can be prepared by treating a fired ceramic article with a leachant, e.g., hydrofluoric acid or a precursor thereof.
Inventors
- 👤 Kenneth E. Owens
- 👤 Robert A. Hatch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:39
CPC Classifications
C; C12; C12N; C12N11/00; C12N11/14; B; B01; B01J; B01J37/00; B01J37/02; B01J37/024; C04; C04B; C04B35/00; C04B35/622; C04B35/62227; C04B35/62231; C04B38/00; C04B38/04; D; D01; D01F; D01F9/00; D01F9/08; G; G01; G01N; G01N30/00; G01N30/02; G01N30/50; G01N30/52; G01N2030/524; G01N2030/528; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2929; Y10T428/2933; Y10T428/2964; Y10T428/2973; Y10T428/2978; Y10T428/2982
Claims Analysis
Total Claims: 52
Claim 1
Independent Claim
65 words
A fired, non-vitreous, non-fused, monolithic, ceramic article characterized by having a core and a sheath or outer layer, at least a portion of said core being enveloped or covered by said sheath or outer layer, said sheath or outer layer having a structure characterized by interconnected micropores, said micropores having an average diameter of less than 300 Å, said core having a substantially non-porous structure.
Claim 2
Dependent Claim
65 words
A fired, non-vitreous, non-fused, monolithic, ceramic article characterized by having a core and a sheath or outer layer, at least a portion of said core being enveloped or covered by said sheath or outer layer, said sheath or outer layer having a structure characterized by interconnected micropores, said micropores having an average diameter of less than 300 Å, said core having a substantially non-porous structure.
Claim 3
Dependent Claim
27 words
The article of claim 1 wherein said ceramic article comprises silica and at least one oxide selected from the group consisting of alumina, zirconia, and mixtures thereof.
Claim 4
Dependent Claim
25 words
The article of claim 2 wherein said ceramic article further includes at least one oxide selected from the group consisting of boria, chromia, and titania.
Claim 5
Dependent Claim
13 words
The article of claim 1 wherein said ceramic article comprises alumina and zirconia.
Claim 6
Dependent Claim
15 words
The article of claim 1 wherein said article is in the form of a fiber.
Claim 7
Dependent Claim
12 words
The article of claim 5 wherein said fiber is a continuous fiber.
Claim 8
Dependent Claim
12 words
The article of claim 5 wherein said fiber is a non-continuous fiber.
Claim 9
Dependent Claim
16 words
A fiber-reinforced plastic composite comprising a plastic material and at least one article of claim 5.
Claim 10
Dependent Claim
16 words
A fiber-reinforced metal composite comprising a metal matrix and at least one article of claim 5.
Claim 11
Dependent Claim
11 words
A woven fabric comprising a plurality of articles of claim 5.
Claim 12
Dependent Claim
11 words
A non-woven fabric comprising a plurality of articles of claim 5.
Claim 13
Dependent Claim
15 words
The article of claim 1 wherein said article is in the form of a bead.
Claim 14
Dependent Claim
15 words
The article of claim 1 wherein said article is in the form of a coating.
Claim 15
Dependent Claim
18 words
The article of claim 1 wherein said article is in the form of a solid or hollow spheroid.
Claim 16
Dependent Claim
15 words
The article of claim 1 wherein said article is in the form of a flake.
Claim 17
Dependent Claim
12 words
The article of claim 1 wherein said article is an unshaped aggregate.
Claim 18
Dependent Claim
32 words
The article of claim 1 wherein said article is characterized by having an average sheath or outer layer thickness at least 9 times as great as the average thickness of the core.
Claim 19
Dependent Claim
34 words
The article of claim 1 wherein said article is characterized by having an average sheath or outer layer thickness equal to or less than 1/10 as great as the average thickness of the core.
Claim 20
Dependent Claim
33 words
The article of claim 1 wherein said article is characterized by having an average sheath or outer layer thickness from 1/10 to 9 times as great as the average thickness of the core.
Claim 21
Dependent Claim
16 words
The article of claim 1 wherein said article comprises at least one crystalline or microcrystalline phase.
Claim 22
Dependent Claim
10 words
The article of claim 1 wherein said article is transparent.
Claim 23
Dependent Claim
10 words
The article of claim 1 wherein said article is reflective.
Claim 24
Dependent Claim
38 words
The article of claim 1 wherein said sheath or outer layer is prepared by leaching a ceramic body to separate leachable material from the portion of the body which forms the sheath or outer layer of the article.
Claim 25
Dependent Claim
15 words
The article of claim 23 wherein said ceramic body is derived from a sol-gel process.
Claim 26
Dependent Claim
18 words
The article of claim 23 wherein said ceramic body is leached by a chemical leachant comprising hydrofluoric acid.
Claim 27
Dependent Claim
12 words
The article of claim 25 wherein said leachant is free of water.
Claim 28
Dependent Claim
21 words
The article of claim 25 wherein said leachant further comprises an inorganic or an organic acid in addition to hydrofluoric acid.
Claim 29
Dependent Claim
13 words
The article of claim 25 wherein said chemical leachant comprises hydrofluoric acid vapor.
Claim 30
Dependent Claim
14 words
The article of claim 23 wherein said chemical leachant comprises precursors of hydrofluoric acid.
Claim 31
Dependent Claim
16 words
The article of claim 1 wherein said porous sheath or outer layer contains a fill material.
Claim 32
Dependent Claim
25 words
The article of claim 30 wherein said sheath or outer layer has an index of refraction different from the index of refraction of said core.
Claim 33
Dependent Claim
12 words
The article of claim 30 wherein said fill material is a solid.
Claim 34
Dependent Claim
17 words
The article of claim 30 wherein said fill material is a metal, metal oxide, or metal salt.
Claim 35
Dependent Claim
12 words
The article of claim 30 wherein said fill material is a catalyst.
Claim 36
Dependent Claim
12 words
The article of claim 30 wherein said fill material is a biochemical.
Claim 37
Dependent Claim
13 words
The article of claim 30 wherein said fill material comprises a living organism.
Claim 38
Dependent Claim
11 words
The article of claim 30 wherein said fill material is organic.
Claim 39
Dependent Claim
12 words
The article of claim 37 wherein said fill material is a polymer.
Claim 40
Dependent Claim
11 words
The article of claim 30 wherein said fill material is inorganic.
Claim 41
Dependent Claim
11 words
The article of claim 30 wherein said fill material is magnetic.
Claim 42
Dependent Claim
12 words
The article of claim 30 wherein said fill material is a fluid.
Claim 43
Dependent Claim
12 words
The article of claim 30 wherein said fill material is electrically conductive.
Claim 44
Dependent Claim
22 words
A woven fabric comprising a plurality of articles of claim 30, each of said articles being in the form of a fiber.
Claim 45
Dependent Claim
22 words
A non-woven fabric comprising a plurality of articles of claim 30, each of said articles being in the form of a fiber.
Claim 46
Dependent Claim
28 words
The article of claim 1 wherein the ratio of the porosity of the sheath or outer layer to the porosity of the core is at least about 2.5:1.
Claim 47
Dependent Claim
47 words
Method of preparing the ceramic article of claim 1 comprising the steps of: (1) contacting a ceramic article with a leachant for a sufficient period of time until a sheath or outer layer is formed on the unchanged ceramic core, and (2) recovering the leached ceramic article.
Claim 48
Dependent Claim
11 words
The method of claim 46 wherein said leachant is hydrofluoric acid.
Claim 49
Dependent Claim
18 words
The method of claim 47 wherein said leachant further comprises a mineral acid in addition to hydrofluoric acid.
Claim 50
Dependent Claim
12 words
The method of claim 46 wherein said leachant is hydrofluoric acid vapor.
Claim 51
Dependent Claim
13 words
The method of claim 46 wherein said leachant comprises precursors of hydrofluoric acid.
Claim 52
Dependent Claim
43 words
Method for infiltrating the porous sheath of the ceramic article of claim 1 comprising the steps of: (1) treating the ceramic article of claim 1 with an infiltrate, (2) recovering the infiltrated ceramic article, and, optionally, (3) treating the resultant infiltrated ceramic article.
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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) | 1989-08-11 | 1990-02-10 | 1990-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-11 | 1994-02-10 | 1994-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-11 | 1998-02-10 | 1998-08-12 | $7700.00 | Window Closed / Lapsed |