US5643474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermal barrier coating removal on flat and contoured surfaces
Assignee: General Electric Co
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Filing: 1995-12-26
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Granted: 1997-07-01
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Expires: 2015-12-26
Abstract
Abstract The invention is directed towards a wet chemical process for removing physical vapor deposited or air plasma sprayed thermal barrier coatings from coated parts without damaging or effecting the bond coat or the base metal substrate. The process entails using an autoclave with an organic caustic solution to fully remove the thermal barrier coating.
Inventors
- 👤 D. Sangeeta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:11
CPC Classifications
C; C23; C23G; C23G5/00; C23G5/02; C23G1/00; C23G1/14; C23G1/19; C23G1/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
59 words
A method for removing thermal barrier coatings from flat and contoured surfaces comprising the step of: treating the thermal barrier coated surface in an autoclave with an organic caustic solution at a temperature, a pressure, and a time sufficient to completely remove the thermal barrier coating from the surface without damaging an underlying bond coat or a substrate surface.
Claim 2
Independent Claim
59 words
A method for removing thermal barrier coatings from flat and contoured surfaces comprising the step of: treating the thermal barrier coated surface in an autoclave with an organic caustic solution at a temperature, a pressure, and a time sufficient to completely remove the thermal barrier coating from the surface without damaging an underlying bond coat or a substrate surface.
Claim 3
Dependent Claim
34 words
A method according to claim 1 where the thermal barrier coating is a chemically stabilized zirconia selected from the group consisting of yttria stabilized zirconia, calcia stabilized zirconia, magnesia stabilized zirconia, and mixtures thereof.
Claim 4
Dependent Claim
23 words
A method according to claim 2 where the thermal barrier coating is about 8 weight percent yttria stabilized about 92 weight percent zirconia.
Claim 5
Dependent Claim
19 words
A method according to claim 1 where the organic caustic solution comprises an organic compound, a base, and water.
Claim 6
Dependent Claim
32 words
A method according to claim 4 where the organic compound is a solvent selected from the group consisting methanol, ethanol, propanol, isopropyl alcohol, acetone, liquid carbon dioxide, liquid ammonia, and mixtures thereof.
Claim 7
Dependent Claim
41 words
A method according to claim 4 where the base is a inorganic base or an organic base, where the base is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, triethylamine, tetramethylammonium hydroxide, and mixtures thereof.
Claim 8
Dependent Claim
34 words
A method according to claim 1 where the pressure is between about 100 psi to 3000 psi, where the temperature is between about 150°-250° C., and where the time is between about 0.1-8.0 hours.
Claim 9
Dependent Claim
32 words
A method according to claim 1 where the bond coat is a metal composition selected from the group consisting of aluminum, platinum aluminum, nickel aluminum, nickel-chromium-aluminum-yttrium, iron-chromium-aluminum-yttrium, cobalt-chromium-aluminum-yttrium, nickel-cobalt-chromium-aluminum-yttrium, and mixtures thereof.
Claim 10
Dependent Claim
48 words
A method according to claim 1 where the substrate is a nickel, chromium, or iron based superalloy selected from the group consisting of GTD-111, GTD-222, Rene 80, Rene 41, Rene 125, Rene 77, Rene 95, Inconel 706, Inconel 718, Inconel 625, cobalt-based HS188, cobalt-based L-605, and stainless steels.
Claim 11
Dependent Claim
29 words
A method according to claim 4 where the organic caustic solution is about 1-98 weight percent organic compound, about 1-65 weight percent base, and about 1-35 weight percent water.
Claim 12
Dependent Claim
27 words
A method according to claim 5 where the organic compound approaches a supercritical fluid state during the treatment of the thermal barrier coated surface in the autoclave.
References Cited (Backward Citations)
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US3163524A
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US3419441A
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US3481877A
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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) | 2000-06-30 | 2000-12-30 | 2001-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-06-30 | 2004-12-30 | 2005-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-06-30 | 2008-12-30 | 2009-07-01 | $7700.00 | Window Closed / Lapsed |