US4145234A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for providing aluminum substrates with light-absorptive surface layer
Assignee: Austria Metall AG
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Filing: 1978-03-01
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Granted: 1979-03-20
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Expires: 1998-03-01
Abstract
Abstract To provide a substrate of aluminum with a dark surface layer of high absorption/emission ratio for luminous energy, the degreased and pickled substrate is immersed in a hot chromating bath until an oxide coating of not more than 2.5μ thickness is formed thereon. This coating is then colored black in a hot, acidic dyeing solution (pH between about 0.5 and 5) of potassium permanganate and a nitrate of cobalt or copper.
Inventors
- 👤 Herbert Meissner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:59
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/82; C23C22/83; C23C22/05; C23C22/60; C23C22/66; C23C22/67; C23C22/84; Y; Y10; Y10S; Y10S126/00; Y10S126/907; Y10S126/908
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
129 words
A process for providing a substrate of aluminum with a dark surface layer of high absorption/emission ratio for luminous energy, comprising the steps of immersing said substrate in an oxidizing bath for a period just sufficient to form an oxide coating of not more than about 2.5μ on a surface thereof, rinsing the surface so coated, and thereafter immersing said substrate in an acidic aqueous solution of potassium permanganate and a nitrate of cobalt or copper, said solution having a pH between substantially 0.5 and 5 and a temperature between substantially 90° and 100° C., the proportion of potassium permanganate in said solution ranging between substantially 1 and 200 grams per liter, the proportion of the nitrate in said solution ranging between substantially 1 and 100 grams per liter.
Claim 2
Dependent Claim
129 words
A process for providing a substrate of aluminum with a dark surface layer of high absorption/emission ratio for luminous energy, comprising the steps of immersing said substrate in an oxidizing bath for a period just sufficient to form an oxide coating of not more than about 2.5μ on a surface thereof, rinsing the surface so coated, and thereafter immersing said substrate in an acidic aqueous solution of potassium permanganate and a nitrate of cobalt or copper, said solution having a pH between substantially 0.5 and 5 and a temperature between substantially 90° and 100° C., the proportion of potassium permanganate in said solution ranging between substantially 1 and 200 grams per liter, the proportion of the nitrate in said solution ranging between substantially 1 and 100 grams per liter.
Claim 3
Dependent Claim
15 words
A process as defined in claim 1 wherein the pH ranges between 2 and 3.
Claim 4
Dependent Claim
26 words
A process as defined in claim 1 wherein the potassium permanganate is present in said solution in a proportion of at least 5 grams per liter.
Claim 5
Dependent Claim
25 words
A process as defined in claim 1 wherein the nitrate is present in said solution in a proportion of 5 to 25 grams per liter.
Claim 6
Dependent Claim
15 words
A process as defined in claim 1 wherein said solution contains nitric or acetic acid.
Claim 7
Dependent Claim
27 words
A process as defined in claim 1 wherein said oxide coating is formed in a hot alkaline chromating bath to a thickness on the order of 1μ.
References Cited (Backward Citations)
US1965269A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-19 | 1982-09-18 | 1983-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-19 | 1986-09-18 | 1987-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-19 | 1990-09-18 | 1991-03-20 | $7700.00 | Window Closed / Lapsed |