US3870608A - Process for coloring aluminum or aluminum alloys by anodizing with imperfectly rectified current - Google Patents

Process for coloring aluminum or aluminum alloys by anodizing with imperfectly rectified current Download PDF

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US3870608A
US3870608A US359645A US35964573A US3870608A US 3870608 A US3870608 A US 3870608A US 359645 A US359645 A US 359645A US 35964573 A US35964573 A US 35964573A US 3870608 A US3870608 A US 3870608A
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aluminum
approximately
sulfuric acid
electrolytic solution
component
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US359645A
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Ikuo Mita
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Tokyo Metropolitan Government
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Tokyo Metropolitan Government
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    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02Anodisation
    • C25D11/04Anodisation of aluminium or alloys based thereon
    • C25D11/14Producing integrally coloured layers

Definitions

  • ABSTRACT Aluminum or aluminum alloys are colored by anodizing the aluminum or aluminum alloys in a sulfuric acid electrolytic solution containing oxyacid anion and/or metal salt by imperfectly rectified current.
  • Japanese Patent Publication No. 9805/1969 aluminum or aluminum alloys are anodized to form a film and the resulting film is colored with an organic dye or inorganic coloring materials.
  • Japanese Patent Publication Nos. 14053/1967, l2566/l969 and 19842/1971 and Studies on coloring of aluminum for architectural purposes using inorganic matierials, published by Aluminum Kenchiku Yohin Hyomen Shori Gijutsu Kenkyu Kumiai, Mar. 1, 1972 disclose a coloring process comprising adding various materials to an electrolytic solution and anodizing by AC, DC or a superimposed AC on DC, a so called one step electrolytic process.”
  • electrolytic coloring of an aluminum anodized film in Denki Kagaku, Vol. 3, p. 20, 1935, and Study on Electrolytic coloring method read before the 44th Meeting of Kinzoku Hyomen Gijutsu Kyokai, 1971 discloses a so called two step electrolytic method" comprising producing an anodized oxide film on aluminum or aluminum alloy according to conventional procedure in the first step and subjecting the anodized article to AC or DC electrolysis by dipping the aluminum or aluminum alloy thus anodized in a solution of a metal salt where the aluminum of aluminum alloy is used as one electrode.
  • the method in item l) above necessitates two vessels, i.e. an electrolytic vessel and a coloring vessel for soaking in a separate coloring bath.
  • the two step electrolytic method in item (3) above necessitates two electrolytic vessels so that the operation is complicated.
  • the method in item (2) above gives a monotonous color tone, and can not give varied color.
  • the process of superimposed alternating current on direct current necessitates AC source, DC source and a rectifier-transformer.
  • a process for coloring aluminum or aluminum alloys which comprises anodizing the article of aluminum or alloy of aluminum in a sulfuric acid electrolytic solution containing at least one ingridient selected from the group consisting of oxyacid anion and metal salt by imperfectly rectitied current.
  • An object of this invention is to provide a novel coloring process capable of producing commercially excellent colored anodized film easily.
  • a method of imperfectly rectifying current employed in this invention is that the rectifying is effected imperfectly by by-passing a part of the current by using a resistance upon rectifying single phase or three phase alternating current. This method is much more simple than the conventional process of superimposed alternating current on direct current the apparatus point of view. Further, current obtained by the method of imperfectly rectifying current has a negative component and a positive component which have'the same cycle and thereby there can be produced uniform colored anodized film.
  • coloring is conducted in such a manner as shown below. While the oxyacid anion and/or metal salt added to the sulfuric acid electrolytic solution produced an anodized film on the aluminum or aluminum alloy article by imperfectly rectified current, S ion or negative ion components formed by decomposition of sulfuric acid in the electrolytic solution combines with the positive ion components formed by decomposition of oxyacid anion and- /or metal salt to produce a sulfur compound, a coloring component, in the oxide film layer. Since such coloring component is formed in the anodized film, a highly weatherproof colored film of excellent color can be easily obtained.
  • Examples of the oxyacid ions which maybe added to the sulfuric acid electrolytic solution are SeOf", M00 W0 TeOf', CrOfi, ASO33 AsOfl, and V0
  • Representative metal salts include sulfates, nitrates, phosphates, sulfamates, borates, 'chromates, dichromates, chlorides, silicates and organic acid salts such as oxalates, malonates, tartarates, succinates and the like of nickel cobalt, tin, copper, lead, titanium, cadmium, iron, molybdenum, zirconium and manganese.
  • Prefera ble metal salts are sulfates ofnickel, cobalt, tin, copper, lead, titanium and cadmium.
  • the amount of the oxyacid anion and/or metal salt to be added depends upon the type of oxyacid and metal salt. In general, the amount is determined by taking into consideration solubility in the sulfuric acid electrolytic solution, coloring property and economy, and usually ranges from about 0.1 to 200 g./l., preferred with from about 1 to 100 g./l. However, when the solubility in the electrolytic solution is too low, the coloring disadvantageously lowered.
  • the ratio of positive component to negative component in the imperfectly rectified current is at least 2:l. Preferably such ratio is 2-20zl.
  • the current density of the positive component is 0.5 6.0 A/dm with 1.0 3.0 A/dm preferred and that of the negative component is 0.05 6.0 A/dm with 0.1 3.0 A/dm preferred.
  • the electrolysis was effected by using a carbon plate as one electrode with imperfectly rectified current, i.e. wherein the positive component has a current density of 2.0 A/dm and the negative component has a current density of 0.2 A/dm for 30 minutes to produce a film of bronze color.
  • the colored film was treated with boiling water to seal.
  • EXAMPLE 2 An aluminum plate treated in a way similar to Example 1 above was subjected to electrolysis in an electrolytic bath having the following composition at a bath temperature of 20C.
  • EXAMPLE 3 An aluminum plate treated in a way similar to Example 1 above was subjected to electrolysis in an electrolytic bath having the following composition at a bath temperature of 20C.
  • Sulfuric acid Selenic acid The electrolysis was effected by using a carbon plate as one electrode with imperfectly rectified current, i.e. wherein the positive component has a current density of 3.0 A/dm and the negative component has a current density of 0.2 A/dm for 40 minutes to produce a deep orange film. The resulting colored film was treated with boiling water to seal.
  • EXAMPLE 4 An aluminum plate treated in a way similar to Example 1 above was subjected to electrolysis in an electrolytic bath having the following composition at a bath temperature of 25C.
  • the electrolysis was conducted by using a carbon plate as one electrode with imperfectly rectified current, i.e. wherein the positive component has a current density of 3.0 A/dm and the negative component has a current density of 1.2 A/dm' for 30 minutes to produce a grayish film.
  • the resulting colored film was treated with boiling water to seal.
  • EXAMPLE 5 An aluminum plate treated in a way similar to Example l was subjected to electrolysis in an electrolytic bath having the following composition at a bath temperature of 25C.
  • the resulting film was treated with boiling water to seal.
  • EXAMPLE 6 An aluminum plate treated in a way similar to Example l was subjected to electrolysis in an electrolytic bath having the following composition at a bath temperature of 20C.
  • the electrolysis was conducted by using a carbon plate as one electrode with imperfectly rectified current, i.e., wherein the positive component has a current density of 2.5 A/dm and the negative component has a current density of 0.2 A/dm for 30 minutes to produce a film of bronz color.
  • the resulting colored film was treated with boiling water to seal.
  • EXAMPLE 7 An aluminum plate treated in a way similar to Example l was subjected to electrolysis in an electrolytic bath having the following composition at a bath tem perature of 20C.
  • the electrolysis was effected by using a carbon plate as one electrode with imperfectly rectified current, i.e. wherein positive component has a current density of 3.0 A/dm and the negative component has a current density of 0.3 A/dm' for 30 minutes to produce a grayish orange film.
  • the resulting colored film was treated with boiling water to seal.
  • a process for coloring an article of aluminum or alloys of aluminum comprising anodizing the article in a sulfuric acid electrolytic solution containing at least one ingredient selected from the group consisting of SeOf", M00 W0 TeOf, CrOf, CrO AsO AsOf, V0 sulfates.
  • a process according to claim 1 wherein the ingredient contained in the sulfuricacid electrolytic solution is selected from the group consisting of a sulfate of nickel. cobalt. tin. copper. lead. titanium and cadmium.
  • a process according to claim 1 wherein the current density of the positive component is approximately 1.0 to 3.0 A/dm and that of the negative component is approximately 0.1 to 3.0 A/dm 5.
  • a process according to claim 1 wherein the ratio of positive component to negative component is approximately 2-20:l.
  • a process according to claim 5 wherein the ingredient contained in the sulfuric acid electrolytic solution is selected from the group consisting of a sulfate of nickel, cobalt, tin, copper, lead, titanium and cadmium; wherein the amount of the ingredient in the sulfuric acid electrolytic solution is approximately l to 100 g./l.; and wherein the current density of the positive component is approximately 1.0 to 3.0 A/dm and that of the negative component is approximately 0.1 to 3.0 A/dm

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrochemical Coating By Surface Reaction (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
US359645A 1972-05-18 1973-05-14 Process for coloring aluminum or aluminum alloys by anodizing with imperfectly rectified current Expired - Lifetime US3870608A (en)

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JP4862172A JPS5315014B2 (zh) 1972-05-18 1972-05-18

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4571287A (en) * 1980-12-27 1986-02-18 Nagano Prefecture Electrolytically producing anodic oxidation coat on Al or Al alloy
US20070267299A1 (en) * 2003-01-30 2007-11-22 Yoshiyuki Mitani Method for Forming Anodic Oxide Layer on Surface of Aluminum or Aluminum Alloy
US20130299353A1 (en) * 2012-05-12 2013-11-14 Catcher Technology Co., Ltd. Method of forming interference film on surface of aluminum alloy substrate

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5180657A (ja) * 1975-01-11 1976-07-14 Sumitomo Metal Ind Marukozainogasusetsudanhoho oyobi sochi
JPS5297334A (en) * 1976-02-13 1977-08-16 Mitsubishi Metal Corp Device for exfoliating electrodeposited cathode plate in electrolytic refining

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3616311A (en) * 1964-03-20 1971-10-26 Reynolds Metals Co Integral hard coat anodizing system
US3639221A (en) * 1969-12-22 1972-02-01 Kaiser Aluminium Chem Corp Process for integral color anodizing

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3616311A (en) * 1964-03-20 1971-10-26 Reynolds Metals Co Integral hard coat anodizing system
US3639221A (en) * 1969-12-22 1972-02-01 Kaiser Aluminium Chem Corp Process for integral color anodizing

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4571287A (en) * 1980-12-27 1986-02-18 Nagano Prefecture Electrolytically producing anodic oxidation coat on Al or Al alloy
US20070267299A1 (en) * 2003-01-30 2007-11-22 Yoshiyuki Mitani Method for Forming Anodic Oxide Layer on Surface of Aluminum or Aluminum Alloy
US20130299353A1 (en) * 2012-05-12 2013-11-14 Catcher Technology Co., Ltd. Method of forming interference film on surface of aluminum alloy substrate

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Publication number Publication date
JPS4941242A (zh) 1974-04-18
JPS5315014B2 (zh) 1978-05-22

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