Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
  • C25F3/00—Electrolytic etching or polishing
  • C25F3/16—Polishing
  • C25F3/18—Polishing of light metals
  • C25F3/20—Polishing of light metals of aluminium
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
  • C25D11/16—Pretreatment, e.g. desmutting
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
  • C25D11/18—After-treatment, e.g. pore-sealing

Definitions

• the invention relates to a method for producing colored surfaces on parts made of aluminum or aluminum alloys.
• Aluminum parts such as aluminum pressed or rolled profiles, are among others in the building hardware and lighting industry or in particular in the automotive industry with e.g. Window border systems or as decorative frames, moldings and. Like. Used. It is also known to use parts made of aluminum or aluminum alloys that have a colored anodized surface.
• the new method should be characterized in that a variety of colors with color gradations Gold - bronze Light - dark bronze Gray - brown Gray - blue anthracite Light-dark blue Blue-violet when coloring the parts, a simple check of the coloring results and a reproducibility of the individual color nuances is possible at any time.
• An extruded profile made of aluminum alloy AlMg 1 or AlMgSi 0.5 is mechanically ground and polished. Degreasing or cleaning is carried out in two steps.
• Acidic aqueous solution containing phosphoric acid pH 1.1 Acidic aqueous solution containing phosphoric acid pH 1.1.
• the profile is electrolytically alkaline polished in order to achieve a sufficient glossy surface reflection.
• the electrolyte contains: Na3PO4 (trisodium phosphate) 120 g / l Na2CO3 (disodium carbonate) 330 g / l Al Po4 (aluminum phosphate) 10 g / l Extracts from beech wood 5 m / l Current density 3 A / dm2 operating temperatur 70 - 80 o C Exposure time 18 min
• the aluminum treated in this way is rinsed in water. Then the oxide layer is removed in a chromic acid solution 50 g / l CrO3 at 98 o C and an exposure time of 3 min.
• the aluminum is rinsed in a sodium hydrogen sulfite solution in order to reduce the 6-valent chromium to the 3-valent chromium.
• the profile is anodized electrolytically using direct current.
• the electrolyte contains: H2SO4 (sulfuric acid) 180 g / l Al 8 g / l Surfactants (wetting agents) 30 ml Current density 1.5 A / dm2 operating temperatur 18 - 20 o C Exposure time 35 min anodic layer thickness 12 ⁇ m
• the profile is exposed in an electrolyte containing metal salts using alternating current.
• hues of gold-bronze and light-dark bronze are achieved under the same operating conditions with different exposure times.
• the electrolyte contains: SnSO4 (tin sulfate) 15 g / l Sn (tin as tin sulfate) H2SO4 (sulfuric acid) 15 g / l Oxicarboxylic acid 30 ml / l operating temperatur 20 - 22 o C Current density 1.5 A / dm2 PH value 1.0
• tin is deposited in the pores of the okyd layer by electrolytic metal deposition.
• the colors gold-bronze and light-dark bronze are achieved with variable current densities and different exposure times from 10 seconds to 15 minutes. If the profile is to be given a color other than that described above, the exposure time for metal deposition is limited to 10 - 30 seconds, with variable current densities resulting in different color gradations. This parameter-controlled metal deposition achieves a basic color, while the adsorption capacity of the oxide layer is retained.
• the adsorption capacity of the Okyd layer is used to variably change the basic coloring through chemical incorporation of an organic azo dye.
• the chemical dye bath contains: Azo dye 1 g / l fungicide 0.4 ml / l PH value 3.5 - 3.9 operating temperatur 50 o C Exposure times 90-180 seconds
• pigment parts of the azo dye are deposited in the pores of the oxide layer in addition to the previously deposited metal salt and thus change the basic color.
• the oxide layer is compacted as the last treatment step and thus protected against external influences.
• the profile is pretreated in a 6% cobalt fluoride, 30% nickel fluoride solution in demineralized water at 30 ° C. for about 10 minutes.
• the profile at 70 ° C in demineralized water with the addition of a scale inhibitor in 2 ml / l triazine derivative 50 minutes is treated.
• the increase in volume of the layer closes the pores.
• the layer is now protected against external influences.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
• Chemical Treatment Of Metals (AREA)
• Printing Plates And Materials Therefor (AREA)
• Other Surface Treatments For Metallic Materials (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

ID=6381456

Family Applications (1)

Country Status (4)

Cited By (1)

Families Citing this family (13)

Family Cites Families (34)

• 1989
  • 1989-05-26 DE DE3917188A patent/DE3917188A1/de active Granted
• 1990
  • 1990-03-23 DE DE9090105561T patent/DE59002262D1/de not_active Expired - Fee Related
  • 1990-03-23 EP EP90105561A patent/EP0399172B1/fr not_active Expired - Lifetime
  • 1990-05-23 US US07/528,130 patent/US5102508A/en not_active Expired - Fee Related
  • 1990-05-28 JP JP2135543A patent/JPH0313596A/ja active Granted

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