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US4473446A
Expired / Lapsed
US
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Chromic acid-fluoride anodizing surface treatment for titanium
Assignee: Boeing Co
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Filing: 1983-01-06
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Granted: 1984-09-25
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Expires: 2003-01-06
Abstract
Abstract A method for surface treating titanium articles prior to adhesive bonding by anodization in a chromic-hydrofluoric acid bath at a low anodizing potential of greater than one volt but less than five volts.
Inventors
- 👤 Melvin C. Locke
- 👤 Joseph A. Marceau
- 👤 Kevin M. Harriman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:21
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/02; C25D11/26
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
109 words
A method of forming a porous adhesion-promoting oxide coating on a titanium article comprising the steps of: anodizing said titanium article in an aqueous anodizing solution comprising fluoride ions and an oxidizing electrolyte for at least five minutes, the anodizing temperature of said solution being at least about 50° F., the fluoride ion concentration of said solution being such as to result in a current density of from about 0.5 amperes per square foot to about 3/0 amperes per square foot, the anodizing potential of said solution ranging from greater than one volt to less than five volts, and rinsing said aqueous anodizing solution from said article with water.
Claim 2
Independent Claim
109 words
A method of forming a porous adhesion-promoting oxide coating on a titanium article comprising the steps of: anodizing said titanium article in an aqueous anodizing solution comprising fluoride ions and an oxidizing electrolyte for at least five minutes, the anodizing temperature of said solution being at least about 50° F., the fluoride ion concentration of said solution being such as to result in a current density of from about 0.5 amperes per square foot to about 3/0 amperes per square foot, the anodizing potential of said solution ranging from greater than one volt to less than five volts, and rinsing said aqueous anodizing solution from said article with water.
Claim 3
Dependent Claim
24 words
The process of claim 1 wherein said anodizing solution is rinsed from said article within two minutes after the cessation of the anodizing current.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein said anodizing potential ranges from about three volts to less than five volts.
Claim 5
Dependent Claim
16 words
The method of claim 3 wherein said anodizing potential ranges from 3.5 volts to 4.5 volts.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein said anodizing temperature ranges from about 50° F. to about 80° F.
Claim 7
Dependent Claim
22 words
The process of claim 5 wherein said anodizing temperature of said anodizing solution ranges from about 60° F. to about 70° F.
Claim 8
Dependent Claim
24 words
The method of claim 1 further comprising the step of: immersing said titanium article in an acid pickling bath prior to anodizing said article.
Claim 9
Dependent Claim
26 words
The method of claim 1 wherein said anodizing solution comprises a solution of chromic acid and hydrofluoric acid having a pH of less than about 6.0.
Claim 10
Dependent Claim
53 words
The method of claim 1 further comprising: prior to anodizing said article, immersing said article in a mild alkaline etching solution maintained at a temperature of about 160° F. to about 220° F. for a period of at least about fifteen minutes, and thereaftet rinsing said etching solution from said article with water.
Claim 11
Dependent Claim
22 words
The method of claim 9 wherein said alkaline etching solution is maintained at a temperature of from 160° to about 180° .
Claim 12
Dependent Claim
19 words
The method of claim 1 wherein said current density ranges from about 0.75 to 1.75 amperes per square foot.
Claim 13
Dependent Claim
20 words
The method of claim 1 wherein said titanium article is anodized for a period of from twenty to twenty-two minutes.
References Cited (Backward Citations)
US3959091A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-25 | 1988-03-26 | 1988-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-25 | 1992-03-26 | 1992-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-25 | 1996-03-26 | 1996-09-25 | $7700.00 | Window Closed / Lapsed |