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
• • 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
  • C23C22/364—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 manganese cations
• • 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
  • C23C22/40—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 molybdates, tungstates or vanadates
  • C23C22/44—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 molybdates, tungstates or vanadates containing also fluorides or complex fluorides
• • 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
  • C23C22/82—After-treatment
  • C23C22/83—Chemical after-treatment

Definitions

• the invention relates to a method for coating metallic surfaces with an optionally colored conversion layer, in particular to replace alkali phosphating such as iron phosphating, correspondingly coated substrates with metallic surfaces and the use of these coated substrates.
• alkali metal phosphate coatings in particular as pre-treatment layers before painting, have been described in isolated cases.
• the fresh alkali metal phosphate solutions that have not yet been used usually have practically no or only a very low content of aluminum, iron and zinc.
• the aqueous acidic alkali phosphate solutions also contain phosphate ions and, due to the pickling effect of these solutions on the metallic surfaces, ion content of the metals eluted from the metallic surfaces, such as e.g. aluminium, iron and/or zinc, as well as traces of alloying components of the pickled metallic materials.
• the main phases formed in the alkali phosphate layer during alkali phosphating are the corresponding phosphates, oxides and/or hydroxides of the metals from the surfaces of the base substrates to be treated.
• Alkaline phosphate solutions or coatings are also referred to as iron phosphate solutions or coatings when used on iron and steel materials.
• Alkaline phosphate coatings are after Werner Rausch: The phosphating of metals, Saulgau 1988 (see in particular pages 109 - 118 ), generally also referred to as layers of the so-called “non-layer-forming phosphating". This designation is misleading, since layers are also formed here, which are significantly thinner than other phosphate layers, such as the various types of zinc phosphating.
• the alkaline phosphate solution always contains an increased content of at least one alkali metal such as sodium and/or ammonium.
• Alkaline phosphating can usually be carried out in a simple and inexpensive manner.
• high-quality alkali phosphate coatings only show limited corrosion protection, usually a) corrosion protection no better than, i.e. no less than 3 mm infiltration, tested in the salt spray test according to DIN 50021 NSS over 500 hours for a powder coating based on epoxy-polyester -Powder paint with a thickness of 60 to 80 ⁇ m on a sheet of cold-rolled steel or usually b) corrosion protection no better than, i.e.
• alkali phosphating it is therefore usually necessary in the case of alkali phosphating to apply an additionally applied second conversion layer and usually also at least one subsequently applied lacquer layer.
• Such multi-stage processes are not only particularly complex, but also require additional baths and/or treatment zones and possibly also additional rinsing steps and/or drying steps and are also costly and time-consuming.
• the paint adhesion of the alkali phosphate coating is often insufficient, so that an additional conversion coating, for example based on zirconium hexafluoride and/or silane, has to be applied before painting. This makes the coating process particularly complex and expensive.
• the high phosphate content of alkali phosphating is also disadvantageous, since phosphate in the waste water has to be disposed of in a complex manner.
• Alkaline phosphating is often applied in several stages, with the first stage primarily just cleaning and the second stage forming the layer. This is followed by rinsing or rinsing.
• U.S. 2011/111235 A1 and U.S. 2011/189488 A1 discloses in each case a process for coating metallic surfaces with an acidic aqueous conversion composition which has a pH in the range from 2.5 to 6.5 and which contains a total of 0.01 to 1 g/l of ZrF 6 2- or/and TiF 6 2- in the form of ions calculated as ZrF 6 2- , 0.01 to 1 g/l of Mn ions or of Zn ions and a polymer/copolymer.
• the object was to find aqueous compositions which can be applied in a simple manner, which are composed as environmentally friendly as possible and which give better protection against corrosion than high-quality alkali phosphate coatings.
• the ions of TiF 6 2- , ZrF 6 2- or/and HfF 6 2- are largely equivalent and interchangeable in the acidic aqueous conversion composition, but in many cases the ions of ZrF 6 2- provide the best properties of the conversion coating produced herewith.
• the content of TiF 6 2- , ZrF 6 2- and/or HfF 6 2- in the acidic aqueous conversion composition is preferably 0.05 to ⁇ 1 g/l, 0.1 to 0.8 g/l, 0.15 to 0.50 g/L or 0.20 to 0.33 g/L.
• a cation content of the acidic aqueous conversion composition only of Fe 2+ ions based on the total content of Fe 2+ , Mn and Zn ions, this content originates at least partially from an intentional addition.
• the ions of manganese and zinc and to a limited extent also of Fe 2+ are largely equivalent and interchangeable in the acidic aqueous conversion composition, but in many cases the ions of manganese and/or zinc provide the best properties of the conversion coating produced herewith.
• manganese and zinc are added to the acidic aqueous conversion composition, it is particularly preferred to achieve a manganese content that is higher than the zinc content.
• It preferably contains 0 or 0.01 to 0.3 g/L or 0.02 to 0.15 g/L of Fe 2+ ions and 0.01 to 1 g/L of Mn ions or/and 0, 01 to 1 g/L or 0.1 to 0.6 g/L of Zn ions. It particularly preferably contains 0.1 to 0.6 g/l or 0.2 to 0.4 g/l of Mn ions and/or 0.1 to 0.6 g/l or 0.2 to 0.4 g/L of Zn ions.
• phosphate-free ⁇ 0.1 g/L PO 4
• completely phosphate-free ⁇ 0.1 g/L PO 4
• a phosphate content calculated as PO 4 3- between 0.001 and ⁇ 0.1 g/L cannot be ruled out, in particular due to carryover and contamination.
• organic polymer and/or organic copolymer contributes to the properties of the conversion coating produced thereby being improved even further and to the fact that subsequent painting can be dispensed with, if appropriate.
• the content of organic polymer and/or organic copolymer in the acidic aqueous conversion composition is preferably 0.1 to 2 g/l, 0.2 to 2 g/l, 0.4 to 1.5 g/l or 0.6 to 1 .2g/L.
• the organic polymer and/or copolymer is based on (meth)acrylate/(meth)acrylic acid and/or vinyl acetate-acrylic copolymer.
• the coating produced can be referred to as a passivation layer and the corrosion protection can be referred to as bare corrosion protection.
• SiO 2 nanoparticles can show a similar positive effect as an addition of organic polymer and / or organic copolymer, but often with the difference that the layer formation and thus the Coating with SiO 2 is even more uniform.
• At least one nonionic, anionic, cationic and/or zwitterionic surfactant can be added in each case.
• An addition of at least one nonionic surfactant is particularly preferred here.
• Anions selected from the group consisting of carbonate, nitrate and sulfate are often added via the addition of cations via water-soluble salts.
• nitrates are particularly preferred.
• carboxylate anions for example via acetic acid and/or via a manganese carboxylate
• carboxylate anions is in principle possible as an alternative or supplement to these anions and is often well suited to avoiding or reducing the anions of mineral acids.
• carboxylic acids and their derivatives such as salts and esters that are water-soluble can be added are stable within the pH value range, which do not have a complicated composition of substances, which form anions in water which, depending on the type and amount of the anions, do not impair layer formation and which, if appropriate, complex alkali and/or alkaline earth metal ions which do not participate in layer formation.
• carboxylate anions these are in particular aliphatic carboxylic acids and mono-, di- and/or polycarboxylic acids such as hydroxycarboxylic acids.
• carboxylate anions care must be taken to ensure that they do not impair layer formation, since citrate and other individual complexing agents, for example, can impair layer formation, depending on the type and quantity of the anions.
• sulfonic acid such as methanesulfonic acid, amidosulfonic acid and/or one of their derivatives can be beneficial here in order to act as an accelerator and/or as a further counterion.
• molybdate content calculated as MoO 4 , of 0 or in the range from 0.01 to ⁇ 0.1 g/l is preferred.
• the addition of molybdate has only proven its worth when the amounts added are very small.
• P-containing oxyanions such as orthophosphate, condensed phosphates and phosphonates should be avoided, in particular because of a possible pollution of waste water and possibly also because of increased sludge formation, which can lead to expensive disposal of waste water and/or sludge.
• P-containing oxyanions it is preferred for reasons of environmental compatibility and to avoid disposal costs that no content of P-containing oxyanions is added, and it is preferable to ensure that no content of P-containing oxyanions is entrained .
• contents of lithium, sodium, potassium and/or ammonium are usually unavoidable in order to achieve charge equalization and not only to add polyvalent cations such as heavy metal ions.
• polyvalent cations such as heavy metal ions.
• sodium ions are particularly preferred. They are largely equivalent and interchangeable in the acidic aqueous conversion composition and are often necessary for pH control.
• cobalt and/or nickel are also advantageous here in order to achieve better protection against corrosion, even if these elements are problematic in terms of environmental compatibility and industrial hygiene.
• An addition of at least one accelerator is sometimes beneficial, in particular an addition of a chlorate, nitrite and/or peroxide. However, it is important to ensure that the quantity is suitable, for example an NO 2 content of significantly less than 1 g/L. If at least one accelerator is added, layer formation can be accelerated and the properties of the coating produced therewith can be improved. Here, an overdose of accelerator is to be avoided in order not to impair the layer formation as in example B40. The addition of nitroguanidine has not been shown to be beneficial.
• the level of complex fluoride(s) alone often results in a low level of free fluoride.
• a content or/and addition of at least one fluoride can lead to a slightly higher content of free fluoride.
• the salary is often free fluoride, which is particularly favorable for aluminum-containing substrate surfaces, in the range from 0.01 to 0.5 g/L, calculated as F - .
• An addition of at least one vanadium compound can also significantly increase corrosion protection.
• ions and substances from other areas of the system may be entrained in small quantities despite rinsing with water.
• levels of alkali metals, ammonium, complexing agents, surfactants, anionic impurities in the cleaning bath and/or other impurities or their ions can be introduced into the bath composition according to the invention.
• a separate preceding cleaning step is not necessarily provided, so that the entry of foreign ions through a chemical treatment solution can be largely ruled out.
• a cleaning step can be carried out with water containing surfactants and without a cleaner structure (builder).
• the cleaning can take place before the conversion coating, so that before the substrate is brought into contact with the aqueous composition, it is cleaned, in particular with an alkaline cleaning.
• the aqueous composition can also contain at least one surfactant in addition to or instead of this cleaning step, so that the cleaning and conversion coating (also) take place in the same process step.
• the aqueous conversion composition preferably has no content or only a small content, such as up to 0.1 g/L, of carboxylic acids, phosphates, phosphonates and/or compounds and/or ions of calcium, chromium, chromate, cobalt, copper, magnesium, Molybdenum, nickel, vanadium and/or tin intentionally added.
• No silane/silanol/siloxane/polysiloxane content is intentionally added to the aqueous conversion composition.
• Silane/silanol/siloxane/polysiloxane means silane, silanol, siloxane and/or polysiloxane, because in water and during coating, e.g. starting from a silane, silanols and/or siloxanes can very quickly result, which sometimes also - depending on the chemical definition - polysiloxanes can arise.
• the combined content of alkaline earth metals such as calcium and/or magnesium in the acidic aqueous conversion composition is preferably no greater than 0.2 g/l in order to avoid precipitation in the presence of fluorides as far as possible.
• the acidic aqueous conversion composition has a pH in the range of 2.5 to 6.5 and contains, consists essentially of or consists in all of:
• Mn and/or Zn ions are added, while the content of Fe 2+ ions is preferably etched out of the iron-rich metallic substrate only by the pickling effect of the acidic conversion composition.
• the coating is then painted at least once.
• the bath composition according to the invention can preferably be prepared by diluting one or two concentrates with water by a dilution factor in the range from 5:1 to 40:1.
• the second concentrate could, for example, contain at least one surfactant and also be aqueous.
• fluoride can also be added as monofluoride, as bifluoride and/or in the form of the corresponding acids.
• the free fluoride content is often in the range of 0.01 to 0.2 g/L.
• city water with a conductance of, for example, 200 to 600 ⁇ S/cm or deionized water is preferably used, both for the preparation and for topping up the liquid level in the bath, as well as for the first rinse after the conversion coating.
• Paint adhesion and corrosion protection tend to be slightly less good on hot-dip galvanized steel (HDG) sheets than on cold-rolled steel (CRS) sheets.
• HDG hot-dip galvanized steel
• CRS cold-rolled steel
• a content of Fe 2+ ions often does not deteriorate the properties of the coating, but it is found that Fe 2+ ions are gradually oxidized to Fe 3+ and deposited as bath sludge. It is therefore preferred that the acidic aqueous conversion composition has a content of manganese and/or zinc ions.
• a surfactant-containing aqueous composition can help to further improve cleaning either after degreasing and/or pickling or at least to avoid degreasing before conversion coating, so that cleaning can be carried out in a one-pot process and so that the cleaning step is eliminated and in As part of the conversion coating takes place.
• At least one substrate with metallic surfaces is contacted with the aqueous composition for a time in the range from 1 second to 10 minutes, in particular from 0.5 to 10 minutes when treating parts. Particularly preferably, it is brought into contact for a time in the range from 1 to 10 minutes, in particular when dipping, or preferably from 0.5 to 6 minutes, in particular when spraying.
• composition according to the invention can also be applied to a strip if it is rinsed with water after strip coating (rinse method).
• the metallic coil is preferably contacted with the aqueous composition for a time ranging from 1 second to 2 minutes.
• the substrate with metallic surfaces has a temperature in the range from 5 to 90°C and preferably in the range from 15 to 70°C or 30 to 60°C when it comes into contact with the aqueous composition.
• the aqueous composition has a temperature in the range from 35 to 70°C or from 45 to 60°C when in contact with the substrate with metallic surfaces. This means that the same temperatures can be used with these compositions as with alkali phosphating, in which 50 to 55 °C are often used.
• a temperature in the range of 50 to 55 °C resulted in the most even conversion coatings and also the most even paint layers after painting.
• the object is also achieved with a coated substrate with metallic surfaces that has been coated according to the invention.
• the coating produced in this way has a layer thickness of 0.3 to 3 ⁇ m and/or that the sum of the coating of elementally measured zirconium and/or titanium in the conversion coating is in the range from 1 to 300 mg/m 2 or preferably in the range of 15 to 150 mg/m 2 measured with an X-ray fluorescence (XRF) system.
• XRF X-ray fluorescence
• the coating produced here is colored, iridescent or gray.
• Interference colors of the 1st or higher order preferably occur in the coating produced in this way, or colors in which the interference color is superimposed on the color of ions. These colours are the same or similar to an alkali phosphate coating. The colors often help to approximate the thickness and sometimes also the uniformity and/or quality of a coating. If this is even possible at a greater viewing distance, this is particularly advantageous in a coating process.
• the conversion coating according to the invention produced herewith is then rinsed with water or with an aqueous post-rinse solution, in particular containing silane, organic polymer and/or organic copolymer, and optionally also painted.
• Rinsing can be done with aqueous rinsing solutions such as Gardolene ® D95 containing phenolic resin or Gardolene ® D6890 based on silane.
• the aqueous after-rinse solution particularly preferably contains at least one a) cation selected from alkaline earth metal, aluminum, titanium, yttrium and heavy metal cations, b) organic polymer and/or copolymer, c) silane, silanol, siloxane and/or Polysiloxane or/and d) complex fluoride, where complex fluoride also stands for the corresponding fluorine-containing acid. Aminosilanes with one, two or even more amino groups and/or bissilylsilanes are particularly preferred as silanes.
• a coating is applied with an aqueous acidic composition according to the invention, optionally then rinsed with water and/or then optionally rinsed with an aqueous composition and the at least one coating produced in this way is then painted at least once.
• an aqueous acidic composition based on 0.01 to 1 g/L of TiF 6 2- , ZrF 6 2- and/or HfF 6 2- or only ZrF 6 2- in the form of ions can be used calculated as ZrF 6 2 and 0 or 0.01 to 1 g/L each of Fe 2+ , Mn and/or Zn ions, of which at least one type of these ions has a content in the range of 0.01 to 1 g/L L is included, and optionally 0.01 to 2 g / L of particulate SiO 2 with an average particle diameter ⁇ 0.3 microns, based on the solids content and / or optionally 0.01 to 10 g / L of at least one surfactant, the is essentially phosphate-free and essentially phosphonate-free, a coating is applied, optionally then rinsed with water and/or optionally then with an aqueous composition based on zirconium complex fluoride, silane and/or organic
• the conversion coating produced in this way can preferably be used without a coating with a primer, lacquer or adhesive.
• the conversion coating produced in this way can optionally be coated at least once with a primer, paint or adhesive after at least one rinsing with water and/or with an aqueous post-rinsing solution. So that even with these compositions if required, the same treatment steps, sequences and treatment processes can be used successfully as in alkali phosphating.
• the coating produced herewith can represent an excellent replacement for an alkali phosphate coating such as an iron phosphate coating.
• the at least one substrate with metallic surfaces which has been coated according to the invention, is preferably used as an architectural element, as a container, as a construction or connection element, as a profile element, as a radiator element, as a molded part with a complicated shape and/or as a component in construction, energy technology, vehicle construction, device construction , household appliance construction or mechanical engineering.
• the aqueous conversion compositions according to the invention give excellent coatings which have excellent corrosion resistance, excellent paint adhesion and usually also a clear color.
• the corrosion resistance on steel surfaces is almost as good as that of a high-quality zinc phosphate coating and thus significantly superior to the corrosion resistance of a high-quality alkali phosphate coating, without a rinsing solution being used afterwards to improve the coating properties. With the use of an additional rinsing solution, the corrosion resistance of a high-quality zinc phosphating can even be achieved.
• composition according to the invention and the method according to the invention are particularly advantageous in the chemical pretreatment of surfaces of various steel substrates used in the metalworking industry Find. It is even possible to clean in one step and at the same time apply a paintable conversion layer, for which this three-stage treatment process consisting of cleaning with conversion coatings, rinsing with city water and rinsing with fully deionized water is completely sufficient. Above all, the bath analysis is very easy to handle, since an exact determination of the anions and cations is only rarely necessary, since the pH value and the conductivity provide sufficient information about the chemical bath condition.
• the process of the invention can be used to produce a coloured, iridescent, gray or colorless (as in B40) passivation layer (without painting) or a coloured, iridescent, gray or colorless (as in B40) conversion coating (with painting).
• a passivation layer is also a coating produced by conversion. Therefore, the term "conversion coating" within the meaning of this application also includes the term "passivation layer” as long as or when no paint is applied, e.g. also in the claims.
• the process according to the invention can be used as a replacement for an alkali metal phosphating process or, in some cases, even as a replacement for a zinc phosphating process.
• the products manufactured with the method according to the invention can be used in a variety of ways, in particular as an architectural element, as a container, as a construction or connection element, as a profile element, as a radiator element, as a molded part with a complicated shape and/or as a component in construction, energy technology, vehicle construction, equipment construction , household appliance construction or mechanical engineering and, for example, as radiators, as frames, as panels, as panels, as angles or as components in vehicle or aircraft interiors.
• Gardobond® C made of cold-rolled steel, CRS, made of St14 DC05, Gardobond® HDG/5 made of the corresponding hot-dip galvanized steel, or Gardobond® F made of AA 5005 made of AlMg1 from Chemetall GmbH were used for the coating. Unless otherwise stated, Gardobond ® C standard sheets were used.
• Aqueous conversion compositions according to Table 1 were prepared.
• a non-ionic surfactant from Gardobond ® Additive H7438 was used as the surfactant, which provided additional cleaning of the metal surface.
• the alkaline Gardobond® Additive H 7157 SiO 2 dispersion stabilized with potassium hydroxide from Chemetall GmbH had a solids content of 20% and an average particle size of 0.2 ⁇ m.
• the polymer dispersion 1 AC 2773 based on acrylate from Alberdingk had a solids content of 53%.
• the acrylate-containing copolymer dispersion 2 VA 294 VP from Alberdingk had a solids content of 47%.
• the acrylate-containing copolymer dispersion 3 AS 2084 VP from Alberdingk had a solids content of 53% solids.
• Polymer, copolymer, SiO 2 particles and/or surfactant were added separately to the previously prepared aqueous conversion composition at the end of the mixing process. In individual experiments, ammonium molybdate was added.
• Panels were conversion coated at 55°C for 3 minutes with cleaning effect when surfactant was present. This was followed by rinsing once with service water and then with deionized water before the coated panels were dried at 120° C. in a drying cabinet for at least 10 minutes. When using a different temperature, there was no clear difference in quality.
• a layer of paint was then applied to each of the conversion-coated sheets: either an epoxy-polyester powder paint Interpon ® 700 from Akzo Nobel Powder Coatings GmbH in a layer thickness of 60 to 80 ⁇ m, a wet paint Alexit ® Monolayer based on polyurethane and isocyanate from Mankiewicz in a layer thickness of 60 to 80 microns or a black cathodic dip paint Cathoguard ® 350 from BASF in a layer thickness of 15 to 20 microns in Example B3 or in Examples B45 to B48 a cathodic dip paint Cathoguard ® 800 (KTL) from BASF in a layer thickness of 15 to 20 ⁇ m and then one layer each of an automobile structure according to Daimler Benz from 25-30 ⁇ m filler, 11-15 ⁇ m base coat and 40-50 ⁇ m clear coat.
• an epoxy-polyester powder paint Interpon ® 700 from Akzo Nobel Powder Coatings GmbH in a layer thickness of 60 to 80 ⁇ m
• the paint adhesion of the painted samples was determined using the cross-hatch method according to DIN EN ISO 2409 before and after a 240-hour climate change test.
• the corrosion resistance of the painted samples was determined in the salt spray test according to DIN 50021 over 500 hours in the neutral NSS salt spray test. In contrast to what is usual in the Asian and North American markets, only a single coat of paint was applied.
• the layer weight was measured in mg/m 2 for a deposit of elemental zirconium with the X-ray fluorescence system.
• the element zirconium is often the guiding element for the quality of the coating, depending on the metallic substrate different metal coatings can be deposited on zirconium with the same aqueous composition.
• the examples according to the invention were compared in the comparative examples VB1 and VB2 with a high-quality, internationally widely used alkali phosphating on sheets of Gardobond® C made of cold-rolled steel:
• a Gardoiene ® D 6890 rinsing solution based on aminosilane with surfactant, an Oxsilan ® 9810/3 rinsing solution based on two different aminosilanes and ZrF 6 or a rinsing solution of a polymer dispersion 1 AC 2773 based on acrylate was used before drying at 120 °C in the drying cabinet for at least 10 minutes.
• Table 1 Overview of the compositions of the aqueous baths and the properties of the associated coated samples and coatings Contents in g/L VB1 VB2 VB3 VB4 VB5 VB6 B1 B2 B3 B4 iron phosphating GB A4976 A4976 - - - - - - - Zr as H 2 ZrF 6 - - 0.50 1.00 0.05 0.30 0.30 0.30 0.30 0.30 0.30 Mn - - - - - - 0.15 0.15 0.15 0.15 Zn - - - - - - 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 Surfactant: GBA H7438 4 4 3 3 3 3 3 3 3 3 3 PH value 5.4 5.4 4.8 4.8 4.8 4.8 3.6 3.5 4.2 4.8 5.4 then rinse with Gardolene ® D6800/6 - Yes - - - - - - - - - - color of the layer blue
• the aqueous conversion compositions according to the invention give excellent coatings which, under these conditions, have excellent corrosion resistance, excellent paint adhesion and usually also a distinct color. Both strongly colored and colorless coatings can be produced with these compositions.
• the corrosion resistance on steel surfaces is almost as good as that of a high-quality zinc phosphating and thus far superior to the corrosion resistance of a high-quality alkali phosphating (e.g. B3 compared to VB1).
• the coating properties were determined only after an additional second conversion treatment—in contrast to the examples according to the invention.
• the paint adhesion on steel surfaces is even as good as that of a high-quality zinc phosphating and thus clearly superior to the paint adhesion of a high-quality alkali phosphating.
• the aqueous conversion compositions according to the invention are composed in a very environmentally friendly manner, are advantageous in terms of industrial hygiene and are phosphate-free.
• a post-rinse solution e.g. containing silane, organic polymer and/or organic copolymer
• paint adhesion was achieved on steel surfaces which is at least as good as that of high-quality zinc phosphating , and corrosion resistance at least as good as that of zinc phosphating has also been achieved.
• the acidic aqueous conversion compositions according to the invention are outstandingly suitable for replacing alkali metal phosphating on various metallic substrate surfaces and not just iron phosphating on iron and steel surfaces. This has even resulted in a multi-metal capability in the treatment, so that a mix of different metallic surfaces can be treated simultaneously or one after the other in the same bath.
• Zn and Mn are only deposited in non-significantly measurable amounts based on measurements with X-ray fluorescence analysis.
• Zr is the main component of the layer and can be present, for example, as (Zr(OH) x F y ).
• Zn often acts as a fluoride scavenger at the metal-coating interface, allowing less fluoride to be incorporated into the layer, which Applicant understands leads to better results.
• Zn and Mn are only part of the layer in small amounts and can therefore only be analytically detected more precisely using XPS/ESCA photoelectron spectroscopy.
• the properties of the coatings produced are often best when the Zr layer is highest in comparable tests. However, the Zr layer is different for different steel grades and also for the same steel grade with different surface properties.
• a non-ionic surfactant was also added during the tests, which improved the cleanliness of the metallic surface of the standard CRS Gardobond ® C sheets used. It was therefore possible to dispense with a previous cleaning stage. If, in comparison, no surfactant was added, the properties of the coating did not change, except that there was an increased risk that the metallic surfaces were not sufficiently cleaned, which could have a negative impact on the properties of the coating.

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