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US4115212A
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Electrolytic coloring process for non anodized aluminum and its alloys
Assignee: Rio Tinto France SAS
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Filing: 1978-02-09
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Granted: 1978-09-19
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Expires: 1998-02-09
Abstract
Abstract Electrolytic coloring process for the surface of aluminum or aluminum alloy objects such as designed for the interior or exterior of buildings or even simpler objects such as ski poles, etc., characterized in that the object, without having been previously anodized, is directly subjected to the action of an alternating current at a voltage below the anodization voltage of the aluminum in an aqueous bath consisting of sulfuric acid and boric acid or only sulfamic acid, at least one salt of copper, tin, silver, nickel or gold; the resultant colored film is then coated with a colorless varnish.
Inventors
- 👤 Jos Patrie
- 👤 Gabriel Colombier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:50
CPC Classifications
C; C25; C25D; C25D11/00; C25D9/00; C25D9/04
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
113 words
A process for electrolytic coloring of objects of aluminum and alloys of aluminum comprising subjecting the objects, without previous anodization, to alternating current, at a voltage below the anodization voltage of the aluminum, while immersed in an aqueous bath having a pH less than 2 and containing boric acid, at least one acid from the group consisting of sulfuric acid, sulfamic acid and mixtures thereof, and at least one salt of a metal selected from the group consisting of copper, tin, silver, nickel and gold, the anion of which is selected from the group consisting of sulfate, sulfamate and chloride, and then coating the colored surface of the object with a colorless varnish.
Claim 2
Dependent Claim
113 words
A process for electrolytic coloring of objects of aluminum and alloys of aluminum comprising subjecting the objects, without previous anodization, to alternating current, at a voltage below the anodization voltage of the aluminum, while immersed in an aqueous bath having a pH less than 2 and containing boric acid, at least one acid from the group consisting of sulfuric acid, sulfamic acid and mixtures thereof, and at least one salt of a metal selected from the group consisting of copper, tin, silver, nickel and gold, the anion of which is selected from the group consisting of sulfate, sulfamate and chloride, and then coating the colored surface of the object with a colorless varnish.
Claim 3
Dependent Claim
24 words
The process as claimed in claim 1 in which the object is subjected to the alternating current for a time less than 10 minutes.
Claim 4
Dependent Claim
29 words
The process as claimed in claim 1 in which the object is subjected to the alternating current for a time within the range of 30 seconds to 10 minutes.
Claim 5
Dependent Claim
17 words
The process as claimed in claim 1 in which the colored bath is at about ambient temperature.
Claim 6
Dependent Claim
21 words
The process as claimed in claim 1 in which the object is subjected to alternating currents of 2 to 10 volts.
Claim 7
Dependent Claim
29 words
The process as claimed in claim 1 in which the object is subjected to alternating current at a current density of 0.3 to 0.8 A/dm2 during the steady state.
Claim 8
Dependent Claim
25 words
The process as claimed in claim 1 in which the boric acid is present in the bath in a concentration of less than 50 g/l.
Claim 9
Dependent Claim
26 words
The process as claimed in claim 1 which when sulfuric acid is present in the bath, it is present in an amount of about 2 g/l.
Claim 10
Dependent Claim
25 words
The process as claimed in claim 1 in which sulfamic acid is present in the bath in an amount within the range of 2-10 g/l.
Claim 11
Dependent Claim
23 words
The process as claimed in claim 1 in which the salt is present in the bath in an amount less than 50 g/l.
Claim 12
Dependent Claim
22 words
The process as claimed in claim 1 in which the color coating is formed to a depth of less than 1 micron.
Claim 13
Dependent Claim
20 words
The process as claimed in claim 1 in which the colorless varnish comprises a solution of a colorless acrylic resin.
Claim 14
Dependent Claim
24 words
The process as claimed in claim 12 which includes the step of drying the varnish at a temperature within the range of 100°-150° C.
Claim 15
Dependent Claim
97 words
A process for electrolytic coloring of objects of aluminum and alloys of aluminum comprising subjecting the objects, without previous anodization, to alternating current, at a voltage below the anodization voltage of the aluminum, while immersed in an aqueous bath having a pH less than 2 and containing sulfamic acid and at least one salt of a metal selected from the group consisting of copper, tin, silver, nickel, and gold, the anion of which is selected from the group consisting of sulfate, sulfamate, and chloride, and then coating the colored surface of the object with a colorless varnish.
Claim 16
Dependent Claim
97 words
A process for electrolytic coloring of objects of aluminum and alloys of aluminum comprising subjecting the objects, without previous anodization, to alternating current, at a voltage below the anodization voltage of the aluminum, while immersed in an aqueous bath having a pH less than 2 and containing sulfamic acid and at least one salt of a metal selected from the group consisting of copper, tin, silver, nickel, and gold, the anion of which is selected from the group consisting of sulfate, sulfamate, and chloride, and then coating the colored surface of the object with a colorless varnish.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-18 | 1982-03-20 | 1982-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-18 | 1986-03-20 | 1986-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-18 | 1990-03-20 | 1990-09-19 | $7700.00 | Window Closed / Lapsed |