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
  • C23C22/07—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 phosphates
  • C23C22/23—Condensed phosphates
• • 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
  • C23C22/07—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 phosphates
  • C23C22/08—Orthophosphates
  • C23C22/12—Orthophosphates containing zinc cations
  • C23C22/17—Orthophosphates containing zinc cations containing also organic acids
• • 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
  • C23C22/362—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 also zinc cations

Definitions

• the invention relates to a method for phosphating metals, in particular steel and galvanized steel, by spraying using an aqueous, acid accelerator, zinc and optionally nickel-containing phosphating solution and its use before electrocoating.
• the reduced zinc content compared to the usual phosphating baths leads to improved thin and uniform phosphate coatings, which are very adhesive and durable and are particularly suitable as a basis for the subsequent electrocoating.
• PCT publication WO 84/00386 discloses phosphating solutions with 0.2 to 0.6 g / 1 Zn and Ni in a ratio of 5.2 to 16 mol Ni to 1 mol Zn, the phosphate layers with a particularly high resistance to Have resolution in alkali.
• the Japanese patent publication (according to Chemical Abstracts 99/216843 u) 58 144 477 describes spray phosphating solutions for steel containing 0.1 to 0.5 g / 1 Zn, 15 to 30 g / 1 phosphate and 0.01 to 0.2 g / 1 nitrite.
• the phosphate layers thus produced are particularly suitable for pretreatment subsequent cathodic electrodeposition coating is well suited.
• the object of the invention is to provide a process which does not have the disadvantages of the known processes and which forms uniform, uniform phosphate layers with improved paint adhesion.
• the object is achieved by designing the method of the type mentioned at the outset in accordance with the invention in such a way that the metal surfaces are brought into contact with an aqueous acidic phosphating solution which and contains at least one activator from the group formate, nitrilotriacetate, trichloroacetate and ethylenediaminetetraacetate.
• the method according to the invention is intended in particular for the treatment of iron, steel and galvanized steel. However, it is also suitable for the phosphating of zinc alloys, Aluminum and aluminum alloys.
• the treatment is carried out by spraying, the contact times for iron, steel and aluminum being 90 to 240 seconds, for example, and zinc 5 to 240 seconds.
• the method according to the invention is mostly used at bath temperatures between 30 and 60 ° C.
• the addition of nickel to the phosphating bath generally has a favorable effect on the phosphating speed, the formation of layers on steel surfaces that are difficult to phosphate, on the phosphating of zinc surfaces and on the corrosion protection properties.
• the phosphating solutions to be used in the process according to the invention preferably contain alkali ions, for example Na, K, Li, NH 4 and, if necessary, further anions, for example N0 3 , Cl, 8 ° 4.
• the baths can also contain other cations known in phosphating technology, such as Co, Cu, Mn, Ca, Mg and Fe.
• nitrite and / or nitrobenzenesulfonate are used as oxidation accelerators.
• further oxidation accelerators e.g. Chlorate is possible and can be beneficial.
• An advantageous embodiment of the method according to the invention is to bring the metal surface into contact with a phosphating solution which contains at least one further activator from the group consisting of fluoride, hexafluorosilicate, tetrafluoroborate, glycolate, citrate, tartrate and condensed phosphate.
• the activators to be used in the method according to the invention have an accelerating and comparative effect on the layer formation and control the weight per unit area of the phosphate layers.
• the addition can e.g. over the corresponding acids or alkali salts.
• concentrations in the phosphating solution apply to the activators: 0.5 to 3 g / 1 fluoride; 1 to 5 g / 1 hexafluorosilicate; 3 to 10 g / 1 tetrafluoroborate; 5 to 15 g / 1 formate; 0.3 to 5 g / 1 glycolate; 0.3 to 3 g / 1 nitrilotriacetate; 2 to 15 g / 1 trichloroacetate; 0.1 to 3 g / 1 ethylenediaminetetraacetate; 0.01 to 0.5 g / 1 citrate; 0.03 to 0.8 g / 1 tartrate; 0.03 to 0.3 g / 1 condensed phosphate such as pyro-, tripo
• the weight per unit area of the phosphate layers produced on steel using the method according to the invention is usually between 0.8 and 2.5 g / m 2 .
• activating agents for example based on titanium phosphate, in the pre-rinse bath or in the last cleaning stage is recommended.
• the phosphate layers produced with the method according to the invention are suitable in principle for all purposes for which phosphate layers are suitable.
• the layers bring about an unusually strong improvement in the resistance of the coating film against the infiltration of the coating in the event of corrosive stress as well as a considerable increase in the adhesion of the coating to the metallic substrate in the event of scratching, impact and bending stress.
• electrocoating in particular in cathodic electrocoating, which is why the method is preferably used as a preparation for this type of painting.
• the method according to the invention finds practical application e.g. for the phosphating of car bodies.
• Body steel sheets degreased with mildly alkaline, activating cleaner in the spray process and then rinsed with water were sprayed with the following phosphating solutions for 2 min at 55 ° C., then rinsed with water, passively rinsed with dilute Cr (VI) / Cr (III) solution, rinsed with demineralized water and partly dried and partly cathodically electro-coated.
• the phosphating solutions according to 1 to 7 contained identical as well as the zinc contents indicated in the table.
• the phosphating solutions according to 8 to 11 contained as well as the activator levels listed in the table.
• the phosphating solutions mentioned were adjusted to the phosphating equilibrium with alkali.
• Examples 8 to 11 show clearly the advantages of the procedure according to the invention in comparison with Examples 1 to 6 according to the prior art. Due to the different chemical surface activity of steel sheets from different rolled batches, the absolute value of the visual assessment is subject to certain fluctuations, but without significantly influencing the relative differences.
• a portion of the cathodically coated panels was about / tested with an automobile paint system of a total of 100 micrometers and provided by various methods.
• the results of the sheets treated according to the invention with regard to VW stone chips with a salt spray test, cross-cut after exposure to condensation and bending over the conical mandrel are very good and behave significantly better than Examples 4 and 7 of the prior art.

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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)
• Paints Or Removers (AREA)
• Electrolytic Production Of Metals (AREA)
• Catalysts (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Glass Compositions (AREA)
• Secondary Cells (AREA)
• Materials For Medical Uses (AREA)
• Superconductors And Manufacturing Methods Therefor (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

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ID=6229954

Family Applications (1)

Country Status (10)

Cited By (7)

Families Citing this family (12)

Family Cites Families (14)

• 1984
  • 1984-03-09 DE DE19843408577 patent/DE3408577A1/de not_active Withdrawn
• 1985
  • 1985-02-15 EP EP85200192A patent/EP0154367B1/fr not_active Expired
  • 1985-02-15 DE DE8585200192T patent/DE3564967D1/de not_active Expired
  • 1985-02-15 AT AT85200192T patent/ATE37203T1/de not_active IP Right Cessation
  • 1985-03-05 US US06/708,463 patent/US4637838A/en not_active Expired - Fee Related
  • 1985-03-06 AU AU39574/85A patent/AU575380B2/en not_active Ceased
  • 1985-03-07 ES ES541015A patent/ES8602152A1/es not_active Expired
  • 1985-03-07 CA CA000475958A patent/CA1224121A/fr not_active Expired
  • 1985-03-08 GB GB08506049A patent/GB2155960A/en not_active Withdrawn
  • 1985-03-08 ZA ZA851761A patent/ZA851761B/xx unknown
  • 1985-04-01 CN CN198585101297A patent/CN85101297A/zh active Pending

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