US4894126A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anodic coatings on aluminum for circuit packaging
Assignee: International Business Machines Corp
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Filing: 1988-01-15
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Granted: 1990-01-16
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Expires: 2008-01-15
Abstract
Abstract An anodizing bath for aluminum alloys is disclosed; the aqueous bath solution contains sulfuric acid, citric acid, urea, and ammoniated colloidal silica; the latter three components being a complexing agent, a leveling agent and a stabilizing agent, respectively, so as to result in an oxide layer having and amorphous structure which eliminates the necessity of sealing thick anodic coating.
Inventors
- 👤 Issa S. Mahmoud
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:15
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/02; C25D11/04; C25D11/06; C25D11/16; H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/05; H05K1/053
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
50 words
An aqueous electrolytic anodizing bath for aluminum and its alloys comprising per liter: from about 6 to about 24 ml sulfuric acid, from about 5 to about 10 g complexing agent, from about 2 to about 5 g urea; and from about 4 to about 8 ml ammoniated colloidal silica
Claim 2
Dependent Claim
50 words
An aqueous electrolytic anodizing bath for aluminum and its alloys comprising per liter: from about 6 to about 24 ml sulfuric acid, from about 5 to about 10 g complexing agent, from about 2 to about 5 g urea; and from about 4 to about 8 ml ammoniated colloidal silica
Claim 3
Dependent Claim
12 words
The bath of claim 1 wherein the complexing agent is citric acid.
Claim 4
Dependent Claim
83 words
An improved method of producing on aluminum alloys a thick, stable anodic coating having an amorphous structure comprising: anodizing aluminum alloys in an electrolytic bath, under even agitation, at a temperature in a range from about 5 to about 15 degrees centigrade, with initial current density in a range from about 30 to about 50 amps/sq.ft, said bath containing per liter thereof 974 ml deionized water 20 ml sulfuric acid 5.5 g citric acid 3.0 g urea, and 6.0 ml ammoniated colloidal silica.
Claim 5
Dependent Claim
83 words
An improved method of producing on aluminum alloys a thick, stable anodic coating having an amorphous structure comprising: anodizing aluminum alloys in an electrolytic bath, under even agitation, at a temperature in a range from about 5 to about 15 degrees centigrade, with initial current density in a range from about 30 to about 50 amps/sq.ft, said bath containing per liter thereof 974 ml deionized water 20 ml sulfuric acid 5.5 g citric acid 3.0 g urea, and 6.0 ml ammoniated colloidal silica.
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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) | 1993-01-15 | 1993-07-17 | 1994-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-15 | 1997-07-17 | 1998-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-15 | 2001-07-17 | 2002-01-16 | $7700.00 | Window Closed / Lapsed |