US4297246A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing dense refractory oxide coatings on metallic substrates and the production of catalysts from the coated substrates
Assignee: Ricardo AEA Ltd
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Filing: 1978-10-25
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Granted: 1981-10-27
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Expires: 1998-10-25
Abstract
Abstract The invention is concerned with providing substrates with coatings obtainable from sols, for example to protect the substrate (such as in nuclear reactors or hydrocarbon cracking plant) or to provide a carrier for catalytically active material. Hitherto, coatings obtained from sols have had a high porosity and high surface area so that they have not been entirely satisfactory for the above applications. In the invention, dense, low-porosity coatings are provided by contacting the substrate with a sol of refractory material (e.g. CeO2 or SiO2) convertible to a gel of density at least 40% of the theoretical density of the refractory material, and converting the sol to the gel. Optionally, the gel may be converted to a ceramic coating by firing.
Inventors
- 👤 James A. Cairns
- 👤 Robert L. Nelson
- 👤 James L. Woodhead
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:23
CPC Classifications
G; G21; G21C; G21C3/00; G21C3/02; G21C3/04; G21C3/16; G21C3/20; B; B01; B01J; B01J37/00; B01J37/02; B01J37/0215; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01J13/00; B01J13/0004; B01J13/0047; B01J37/024; C; C23; C23C; C23C18/00; C23C18/02; C23C18/12; C23C18/125; C23C18/1254; C23D; C23D5/00; C23D5/02; C23D5/10; C01; C01P; C01P2004/00; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/10; Y; Y02; Y02E; Y02E30/00; Y02E30/30; Y10; Y10S; Y10S376/00; Y10S376/90
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
132 words
A method of coating a substrate with a refractory oxide selected from the group consisting of ceria, zirconia and titania which comprises the steps of (i) contacting the substrate with a sol of said refractory oxide comprising a dispersion, in a liquid medium, of substantially unaggregated colloidal primary particles of the refractory oxide or of aggregated colloidal primary particles of the refractory oxide and ions which occupy gaps in said aggregated particles, said sol being capable of being converted to a gel of the refractory oxide, the bulk density of the gel being at least 40% of the theoretical density of the refractory material; (ii) converting the sol to a gel to provide the substrate with a gel coating; and (iii) firing to convert the gel coating to said refractory oxide coating.
Claim 2
Independent Claim
132 words
A method of coating a substrate with a refractory oxide selected from the group consisting of ceria, zirconia and titania which comprises the steps of (i) contacting the substrate with a sol of said refractory oxide comprising a dispersion, in a liquid medium, of substantially unaggregated colloidal primary particles of the refractory oxide or of aggregated colloidal primary particles of the refractory oxide and ions which occupy gaps in said aggregated particles, said sol being capable of being converted to a gel of the refractory oxide, the bulk density of the gel being at least 40% of the theoretical density of the refractory material; (ii) converting the sol to a gel to provide the substrate with a gel coating; and (iii) firing to convert the gel coating to said refractory oxide coating.
Claim 3
Dependent Claim
25 words
A method according to claim 1 wherein the bulk density of the gel is at least 45% of the theoretical density of the refractory oxide.
Claim 4
Dependent Claim
16 words
A method according to claim 1 wherein catalytically active material is applied to the coated substrate.
Claim 5
Dependent Claim
15 words
A method according to claim 3 wherein the substrate is an aluminium bearing ferritic alloy.
Claim 6
Dependent Claim
30 words
A method according to claim 4 wherein the alloy has proportions by weight of up to 20% Cr, 0.5 to 12% Al, 0.1 to 3% Y, and the balance Fe.
Claim 7
Independent Claim
111 words
A method of coating a substrate with a refractory oxide which comprises the steps of (i) contacting the substrate with a sol comprising an aqueous dispersion of substantially unaggregated colloidal primary particles of ceria or of aggregated colloidal primary particles of ceria and ions which occupy gaps in said aggregated particles, said sol being capable of being converted to a gel of the refractory oxide, the bulk density of the gel being at least 40% of the theoretical density of the refractory material; (ii) converting the sol to a gel to provide the substrate with a gel coating; and (iii) firing to convert the gel coating to a refractory oxide coating.
Claim 8
Independent Claim
111 words
A method of coating a substrate with a refractory oxide which comprises the steps of (i) contacting the substrate with a sol comprising an aqueous dispersion of substantially unaggregated colloidal primary particles of ceria or of aggregated colloidal primary particles of ceria and ions which occupy gaps in said aggregated particles, said sol being capable of being converted to a gel of the refractory oxide, the bulk density of the gel being at least 40% of the theoretical density of the refractory material; (ii) converting the sol to a gel to provide the substrate with a gel coating; and (iii) firing to convert the gel coating to a refractory oxide coating.
Claim 9
Independent Claim
129 words
A method of coating a substrate with a other than silica which comprises the steps of (i) contacting the substrate with a sol of said refractory oxide comprising a dispersion, in a liquid medium, of substantially unaggregated colloidal primary particles of the refractory oxide or of aggregated colloidal primary particles of the refractory oxide and ions which occupy gaps in said aggregated particles, said sol being capable of being converted to a glass-based material by carrying out steps (ii) and (iii) below: (ii) converting the sol to a gel to provide the substrate with a gel coating, the bulk density of the gel being at least 40% of the theoretical density of the refractory material; and (iii) firing to convert the gel coating to a glass-based refractory oxide coating.
Claim 10
Independent Claim
129 words
A method of coating a substrate with a other than silica which comprises the steps of (i) contacting the substrate with a sol of said refractory oxide comprising a dispersion, in a liquid medium, of substantially unaggregated colloidal primary particles of the refractory oxide or of aggregated colloidal primary particles of the refractory oxide and ions which occupy gaps in said aggregated particles, said sol being capable of being converted to a glass-based material by carrying out steps (ii) and (iii) below: (ii) converting the sol to a gel to provide the substrate with a gel coating, the bulk density of the gel being at least 40% of the theoretical density of the refractory material; and (iii) firing to convert the gel coating to a glass-based refractory oxide coating.
Claim 11
Dependent Claim
26 words
The method of claim 7 wherein the sol is a sol of a refractory metal oxide selected from the group consisting of ceria, zirconia and titania.
Claim 12
Independent Claim
128 words
A method of coating a substrate with a other than silicawhich comprises the steps of (i) contacting a Nb stabilized Cr bearing austentic steel with a sol of said refractory oxide comprising a dispersion, in a liquid medium, of substantially unaggregated colloidal primary particles of the refractory oxide or of aggregated colloidal primary particles of the refractory oxide and ions which occupy gaps in said aggregated particles, said sol being capable of being converted to a gel of the refractory oxide, the bulk density of the gel being at least 40% of the theoretical density of the refractory material; (ii) converting the sol to a gel to provide said austentic steel with a gel coating; and (iii) firing to convert the gel coating to a refractory oxide coating.
Claim 13
Independent Claim
128 words
A method of coating a substrate with a other than silicawhich comprises the steps of (i) contacting a Nb stabilized Cr bearing austentic steel with a sol of said refractory oxide comprising a dispersion, in a liquid medium, of substantially unaggregated colloidal primary particles of the refractory oxide or of aggregated colloidal primary particles of the refractory oxide and ions which occupy gaps in said aggregated particles, said sol being capable of being converted to a gel of the refractory oxide, the bulk density of the gel being at least 40% of the theoretical density of the refractory material; (ii) converting the sol to a gel to provide said austentic steel with a gel coating; and (iii) firing to convert the gel coating to a refractory oxide coating.
Claim 14
Dependent Claim
26 words
The method of claim 9 wherein the sol is a sol of a refractory metal oxide selected from the group consisting of ceria, zirconia and titania.
References Cited (Backward Citations)
US3133829A
Cited
US3518050A
Cited
US3761571A
Cited
US3894963A
Cited
US3785998A
Cited
US3893950A
Cited
US3957692A
Cited
US3966645A
Cited
US3920583A
Cited
US4096095A
Cited
US4070286A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-10-26 | 1985-04-27 | 1985-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-26 | 1989-04-27 | 1989-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-26 | 1993-04-27 | 1993-10-27 | $7700.00 | Window Closed / Lapsed |