Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/34—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides
  • C23C22/36—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides containing also phosphates
  • C23C22/361—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides containing also phosphates containing titanium, zirconium or hafnium compounds
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/34—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides
  • C23C22/36—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides containing also phosphates

Definitions

• the invention relates to a method for applying conversion coatings on aluminum surfaces by means of solutions which contain titanium and / or zirconium, fluoride and phosphate ions, but are free from nitrate, nitrite and chromium ions and from organic film-forming polymers and tannin.
• Such methods work e.g. with an aqueous solution containing hexavalent chromium, trivalent chromium, alkali ions and silicon dioxide in certain proportions and coatings for electrical insulation, for corrosion protection and as a primer for paints and the like. (DE-AS 17 69 582).
• Coatings can also be produced on metal surfaces with the aid of coating compositions which contain a compound of hexavalent chromium and a polymeric organic substance (so-called primer) and are then dried or baked on (AP-PS 197 164).
• coating compositions which contain a compound of hexavalent chromium and a polymeric organic substance (so-called primer) and are then dried or baked on (AP-PS 197 164).
• hexavalent chromium treatment fluids it is also known to clean the metal surface, in particular iron, zinc and aluminum, with an acidic aqueous solution, the chromium III ions, phosphate ions and finely divided silica , optionally also contains acetate, maleinate, zinc and / or manganese ions, to wet and dry the solution film (DE-OS 27 11 431).
• compositions which contain certain amounts of zirconium and / or titanium as well as phosphate and active fluoride (US Pat. No. 4,148,670) or polyacrylic acid or ester and fluozirconic acid, Fluotitanic acid or fluosilicic acid (US Pat. No. 4,191,596) or tannin together with titanium and Fluorine ions (US Pat. No. 4,054,466) or complex fluorides of boron, titanium or zircon together with oxidizing agents, such as sodium metanitrobenzenesuronate (DE-AS 19 33 013).
• phosphate and active fluoride US Pat. No. 4,148,670
• polyacrylic acid or ester and fluozirconic acid Fluotitanic acid or fluosilicic acid
• titanium and Fluorine ions US Pat. No. 4,054,466
• complex fluorides of boron, titanium or zircon together with oxidizing agents such as sodium metanitrobenzenesuronate (DE-AS 19 33 013)
• the last-mentioned methods are disadvantageous in that, due to the water-soluble constituents of the coating agent, a rinsing treatment is required, which often leads to wastewater which is difficult to treat or only a comparatively complicated bath monitoring leads to usable results.
• Coating agents containing tannin sometimes lead to an undesirable discoloration of the treated metal surface. Because of the variety of known tannins, the coating agents are also difficult to reproduce in terms of their effect. Coating agents containing polymers tend to age and become unstable, particularly in the form of concentrates. In particular, a certain incompatibility with subsequently applied organic coatings is also not predictable.
• the object of the invention is to provide a method for applying conversion coatings on aluminum surfaces which avoids the known, in particular the aforementioned disadvantages, and yet can be carried out simply and without additional effort.
• the solution can be brought into contact with the aluminum surface in any conventional manner, such as by dipping and then draining, pouring over and spinning off, brushing, spraying using single or dual-substance nozzles, spraying or rolling on with flat or structured rollers in the same or in the opposite direction will.
• Roll-on processes are particularly suitable because of the comparatively precise dosing of the solution quantities. Applying a solution amount of approx. 3 - 20 ml / m 2 aluminum surface is particularly advantageous. Because of the small amount of water to be evaporated, the amount of solution should be as low as possible.
• the solution film applied to the aluminum surface can be dried at room temperature.
• higher temperatures preferably from 50 to 120 ° C., given as the object temperature, should be aimed for.
• the aluminum surface is brought into contact with a solution in which the molar ratio of phosphate ions to zirconium and / or titanium ions is at most 5.
• this ensures a perfect layer formation, on the other hand it prevents the sparingly soluble zirconium phosphate from precipitating.
• the aluminum surfaces are brought into contact with a solution in such a way that a layer weight of 20-200 mg / m 2 results.
• the aluminum surfaces must be cleaned thoroughly.
• the cleaning can be done with acidic cleaners based on phosphoric acid or sulfuric acid, which should also contain a surfactant, especially non-ionic type, if necessary also fluoride, or with strongly alkaline cleaners, e.g. with sodium hydroxide solution, condensed phosphate and surfactant.
• strongly alkaline cleaners e.g. with sodium hydroxide solution, condensed phosphate and surfactant.
• degreasing can also be carried out with or in addition with halogenated hydrocarbons.
• Aluminum sheets measuring 100 x 200 mm were cleaned in a strongly alkaline cleaner based on sodium hydroxide solution, condensed phosphate, non-ionic surfactant at 65 ° C. for 15 seconds, thoroughly rinsed with water and freed of excess rinsing water by squeezing rollers.
• the cleaned aluminum sheets were then immersed in the treatment solution at the reaction temperature for approx. 1 sec guided between grooved rollers or smooth rollers in such a way that 6 or 3 ml of solution film per m 2 of aluminum surface remained.
• the solution was dried at an object temperature of 80 ° C.
• the aluminum sheets were subjected to several tests.
• the aluminum sheets provided with the conversion coating were coated with an epoxy paint (Mobil SHX 2636) and the paint adhesion was tested according to the T-bending test.
• a second series of aluminum sheets was provided with a gold lacquer and, after the boiling test, subjected to a test for blistering, discoloration and lacquer detachment.
• a hard PVC film was sealed using a PVC-based heat seal lacquer and the film's adhesion was determined after the peel test.
• the table below shows the test results with regard to the paint detachment for the T-bending test in percent - based on the bending point.
• the boiling test consists of first boiling the painted aluminum sheets in deionized water for 3 hours and then assessing the formation of blisters and discoloration.
• some of the metal sheets are additionally subjected to mechanical stress before the cooking treatment in accordance with the aforementioned T-bending test or in accordance with the impact indentation.
• the peeling test is characterized in that sheet metal strips or sheet metal strips 200 mm long and 15 mm wide provided with a conversion coating are provided on one side with a sealing wax and then by means of heated press jaws at a contact pressure of 300 Newton / cm 2 , a contact time of 4 sec and a temperature of the preheated press jaws 180 0C with a PVC-film are provided. After three days of storage in water, the loss of adhesion to a sheet not stored in water is determined by pulling off the film and is given in percent. The pull-off speed of the film is 30 mm / min.

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• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Treatment Of Metals (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6174596

Family Applications (1)

Country Status (8)

Cited By (5)

Families Citing this family (13)

Citations (3)

Family Cites Families (6)

• 1982
  • 1982-09-30 DE DE19823236247 patent/DE3236247A1/de not_active Withdrawn
• 1983
  • 1983-09-16 EP EP83201327A patent/EP0106389A1/de not_active Withdrawn
  • 1983-09-28 ZA ZA837238A patent/ZA837238B/xx unknown
  • 1983-09-28 CA CA000437827A patent/CA1199559A/en not_active Expired
  • 1983-09-29 JP JP58181798A patent/JPS5983776A/ja active Pending
  • 1983-09-29 AU AU19720/83A patent/AU1972083A/en not_active Abandoned
  • 1983-09-30 GB GB08326185A patent/GB2131052A/en not_active Withdrawn
  • 1983-09-30 ES ES526551A patent/ES8405447A1/es not_active Expired

Patent Citations (3)

Non-Patent Citations (3)

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