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
  • C23C22/73—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 characterised by the process
• • 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
  • C23C22/78—Pretreatment of the material to be coated
  • C23C22/80—Pretreatment of the material to be coated with solutions containing titanium or zirconium 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
  • C23C22/73—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 characterised by the process
  • C23C22/76—Applying the liquid by spraying
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
  • C25D13/20—Pretreatment
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/22—Electroplating: Baths therefor from solutions of zinc
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/42—Electroplating: Baths therefor from solutions of light metals
  • C25D3/44—Aluminium

Definitions

• the invention relates to a method for the anti-corrosion pre-treatment of a plurality of components in series, in which the components of the series are at least partially formed of iron and/or steel, and in which the components of the series each initially undergo a first conversion stage, followed by a rinsing stage and a subsequent second conversion stage, wherein, in the conversion stages, respective acidic aqueous conversion solutions based on compounds of the elements Zr and/or Ti dissolved in water are brought into contact with the components, and, additionally, copper ions are contained in the conversion solution for the second stage.
• EP 1 455 002 A1 therefore reports that reducing the proportion of fluorides in the conversion coating can result in an improved corrosion behavior and paint adhesion to a subsequent electrodeposition coating.
• EP 1 455 002 A1 proposes to add magnesium, calcium, an Si-containing compound, zinc, or copper to the conversion solution and alternatively, or in combination, to dry the conversion coating or post-rinse it with an alkaline aqueous composition.
• EP 2 318 566 A1 shows that cascading the rinsing water of the conversion treatment into a pre-rinse before the actual conversion treatment is advantageous for the formation of amorphous coatings based on the elements Zr and/or Ti, in particular on steel surfaces, which protect against corrosion.
• a first slight conversion of the surface takes place during the pre-rinse, which is advantageous for the subsequent construction of the actual conversion layer.
• a sequential layer structure by means of conversion in successive wet-chemical individual steps carried out independently of one another is also used to improve paint adhesion to correspondingly pre-treated steel surfaces. It describes a two-step process for the build-up of a conversion coating based on elements of the secondary groups IIIb/IVb of the periodic table, in particular on the element Zr, consisting of acidic fluoride-containing solutions, which is particularly suitable for a subsequent electrodeposition coating and can be carried out on various metal substrates.
• This object is achieved by a method for the sequential build-up of a conversion coating in two treatment steps that are interrupted by a rinsing stage, wherein the conversion solutions each contain water-soluble compounds of the elements Zr and/or Ti and copper ions are additionally contained in the second conversion stage.
• the present invention relates to a method for the anti-corrosion pre-treatment of a plurality of components in series, in which the components of the series are at least partially formed of iron and/or steel, and in which the components of the series each undergo the successive method steps i)-iii) and at least the surfaces of iron and/or steel of the components are successively brought into contact with the respectively provided aqueous solutions (I)-(III):
• Anti-corrosion pre-treatment of the components in series is when a large number of components are brought into contact with treatment solution provided in the respective treatment stages of the method according to the invention and conventionally stored in system tanks, the individual components being brought into contact successively and thus at different times.
• the system tank is the container in which the treatment solution is located for the purpose of anti-corrosion pre-treatment in series.
• the concentration of an active component or compound is referred to in the context of the present invention as the amount of substance per kilogram, this is the amount of substance based on the weight of the respective total composition.
• the components pre-treated according to the present invention can be three-dimensional structures of any shape and design that originate from a manufacturing process, in particular also including semi-finished products, such as strips, sheets, rods, pipes, etc., and composite structures assembled from said semi-finished products, in particular automobile bodies, the semi-finished products preferably being interconnected by means of adhesion, welding and/or flanging to form a composite structure.
• semi-finished products such as strips, sheets, rods, pipes, etc.
• composite structures assembled from said semi-finished products in particular automobile bodies, the semi-finished products preferably being interconnected by means of adhesion, welding and/or flanging to form a composite structure.
• a solution (I)-(III) is considered to be “provided” in the sense of the method according to the invention if it is either prepared or held ready for contacting as defined in the respective treatment stage (i)-(iii) or is implemented during contact as defined.
• the multi-stage pre-treatment according to the present invention in comparison with a conversion treatment by one-time contacting with an acidic aqueous solution containing compounds of Zr and/or Ti dissolved in water and free fluoride (“conventional single-stage conversion layer formation”), provides defect-free conversion layers with a low fluoride content and a significantly reduced tendency to corrosive delamination of a subsequently built up paint system.
• the combination of a first conversion stage and a second conversion stage, which takes place after the rinsing stage in a conversion solution containing copper ions dissolved in water, is indispensable for this, and the mere reduction of the fluoride content in the conversion coating after the first conversion stage by means of the rinsing stage, which takes place with a rinsing solution containing substantially no free fluoride ions (i.e., less than 0.25 mmol/kg, preferably less than 0.10 mmol/kg, very particularly preferably less than 0.05 mmol/kg of free fluoride), is not sufficient, in particular not for sufficient performance in terms of corrosion protection on the steel and/or iron surfaces of the components of the series.
• substantially no free fluoride ions i.e., less than 0.25 mmol/kg, preferably less than 0.10 mmol/kg, very particularly preferably less than 0.05 mmol/kg of free fluoride
• the amount of free fluoride in the relevant stages of the pre-treatment according to the invention can be determined potentiometrically by means of a fluoride-sensitive measuring electrode at 20° C. in the relevant provided solution after calibration with fluoride-containing buffer solutions without pH buffering.
• the conversion layer formation in method steps i) and iii) is carried out by means of conversion solutions that produce an amorphous oxide/hydroxide coating based on the elements Zr and/or Ti and accordingly contain compounds of the elements Zr and/or Ti dissolved in water.
• the term “dissolved in water” comprises molecularly dissolved species and compounds that dissociate in aqueous solution and form hydrated ions.
• Typical representatives of these compounds are titanyl sulfate (TiO(SO 4 )), titanyl nitrate (TiO(NO 3 ) 2 ) and/or hexafluorotitanic acid (H 2 TiF 6 ) and salts thereof or ammonium zirconium carbonate ((NH 4 ) 2 ZrO(CO 3 ) 2 ) and/or hexafluorozirconic acid (H 2 ZrF 6 ) and salts thereof.
• the compounds dissolved in water are preferably selected from fluoro acids and/or fluoro complexes of the elements Zr and/or Ti in the conversion stages.
• the conversion layer formation based on the fluoro acids and/or fluoro complexes of the element Zr is particularly preferred, because conversion layers of this kind provide improved paint adhesion.
• the pH of the conversion solution is not set to be acidic in order to keep the pickling rate as low as possible during the growth of the conversion layer, in particular in the first conversion stage.
• the pH is in each case above 3.0, more preferably above 3.5, particularly preferably above 4.0, but preferably below 4.5, because otherwise the precipitation of sparingly soluble hydroxides of the elements Zr and/or Ti in the interior of the solution can only be kept under control in a narrow process window during the serial treatment of a plurality of components.
• An embodiment of the method according to the invention is particularly preferred in which the predominant part of the layer formation is already carried out in the first conversion stage and the second conversion stage only serves to remedy defects in the conversion coating formed in the first stage by deposition of a relatively small additional coating on the elements Zr and/or Ti, which is supported by the local cementation of copper at point defects in the conversion layer.
• deposition of Zr and/or Ti beyond the required degree in the second conversion stage in turn significantly worsens the corrosion protection properties. This applies in particular to the surfaces of iron and/or steel of the components pre-treated according to the invention.
• a method according to the invention is preferred in which the contacting with the conversion solution (i) in the first conversion stage in method step (i) takes place at least for a period of time during which a coating of at least 20 mg/m 2 is produced on the surfaces of steel and/or iron, but the contacting is preferably not for so long that a coating of more than 150 mg/m 2 , more preferably more than 100 mg/m 2 , very particularly preferably more than 80 mg/m 2 in each case based on the elements Zr and/or Ti results on these surfaces.
• the contacting with the conversion solution (III) in the second conversion stage in method step (iii) does not continue until there is an increase in the coating of more than 15 mg/m 2 , particularly preferably more than 12 mg/m 2 , very particularly preferably more than 10 mg/m 2 , on the surfaces of steel and/or iron, but the contacting is preferably carried out at least for such a period of time that the coating on these surfaces is increased by at least 2 mg/m 2 in each case based on the elements Zr and/or Ti.
• the layer structure in the conversion stages of the method according to the invention for anti-corrosion pre-treatment is optimally coordinated.
• the treatment time required for this purpose i.e., the duration of contacting with the conversion solution at a temperature in the range of 10-60° C., should be in the range of 10 seconds to 300 seconds.
• the proportion of compounds of the elements Zr and/or Ti dissolved in water is preferably at least 0.15 mmol/kg, more preferably at least 0.25 mmol/kg, particularly preferably at least 0.30 mmol/kg.
• the content of compounds of the elements Zr and/or Ti dissolved in water should be significantly below 10.0 mmol/kg, particularly preferably below 5.0 mmol/kg.
• the proportion of free fluoride is at least 0.5 mmol/kg, particularly preferably at least 1.0 mmol/kg, and very particularly preferably at least 1.5 mmol/kg.
• the proportion of free fluoride should preferably be less than 8.0 mmol/kg, particularly preferably less than 6.0 mmol/kg, very particularly preferably less than 5.0 mmol/kg.
• F/mM and Me/mM are free fluoride (F) or reduced zirconium and/or titanium concentration (Me) reduced by the unit of the concentration in mmol/kg, is greater than 0.80, preferably greater than 1.20, particularly preferably greater than 1.60, so that such conversion solutions are preferred according to the invention.
• Suitable sources of free fluoride in the first conversion stage of method step i) of the method according to the invention are hydrofluoric acid and the water-soluble salts thereof, such as ammonium bifluoride and sodium fluoride, as well as complex fluorides of the elements Zr, Ti and/or Si, in particular complex fluorides of the element Si.
• the source of free fluoride is therefore preferably selected from hydrofluoric acid and its water-soluble salts and/or complex fluorides of the elements Zr, Ti and/or Si.
• Salts of hydrofluoric acid are water-soluble within the meaning of the present invention if their solubility in deionized water ( ⁇ 1 ⁇ Scm ⁇ 1 ) at 60° C. is at least 1 g/L, calculated as F.
• the rinsing stage in method step ii) of the method for sequential conversion coating according to the invention serves on the one hand for the complete or partial removal or dilution of soluble residues, particles and active components that are carried on the component in an adhering manner from the preliminary wet-chemical method step i).
• the removal of soluble residues should also specifically bring about the soluble fluoride species contained in the conversion coating, thus conditioning the first conversion coating for a subsequent passivating deposition of oxidic/hydroxidic Zr and/or Ti compounds and the cementation of copper in the second conversion stage.
• the rinsing solution does not have to contain substantially any active components based on metal or semi-metal elements, which are consumed merely by the metal surfaces of the component being brought into contact with the rinsing liquid by deposition.
• the rinsing liquid can simply be municipal water or deionized water, or, if necessary, a rinsing liquid that can additionally contain redox-active compounds (“depolarizers”) to optimize the conditioning of the metal surface accessible at point defects, or additionally surface-active compounds, such as non-ionic surfactants or anionic surfactants, to optimize wettability with the rinsing solution.
• depolarizers redox-active compounds
• the aqueous rinsing solution (II) provided in the rinsing stage has a concentration of compounds of the elements Zr and/or Ti dissolved in water, which is reduced in comparison with the aqueous conversion solution (I) at least by a factor of 5, preferably at least by a factor of 10, particularly preferably at least by a factor of 20, very particularly preferably at least by a factor of 50, and in this case comprises less than 0.25 mmol/kg, preferably less than 0.10 mmol/kg, particularly preferably less than 0.05 mmol/kg of free fluoride and preferably less than 0.10 mmol/kg of compounds of the elements Zr and/or Ti dissolved in water.
• the continuous reduction of soluble fluoride species in the conversion coating can also be achieved by bringing it into contact with rinsing solutions that contain a reduced concentration diluted by a factor of 5, for example by more than a factor of 100, of compounds of the elements Zr and/or Ti dissolved in water, can also be achieved in that the rinsing stage comprises a plurality of immediately successive rinsing steps, but preferably, for reasons of process economy, not more than three rinsing steps, with rinsing solutions (II) that contain at least one concentration, reduced by a factor of 5, of compounds of the elements Zr and/or Ti dissolved in water.
• the rinsing solution(s) (II) of the rinsing stage contain(s) a total of less than 50 ⁇ mol/kg, preferably a total of less than 15 ⁇ mol/kg, of metal ions of the elements copper, nickel and cobalt that are dissolved in water.
• the pH of the rinsing solution is in the range of 5.0 to 10.0.
• alkaline rinsing solutions can be disadvantageous in that alkalinity is introduced into the second conversion stage, which must be compensated for there by resharpening with acidic substances and additionally promotes the precipitation of active components and thus sludge formation.
• the aqueous rinsing solution (II) preferably at least the rinsing solution of the final rinsing step of the rinsing stage, has a pH above 6.0, but below 9.5, particularly preferably below 8.5 in method step (ii).
• the aqueous rinsing solution (II) of the rinsing stage in method step (ii) therefore additionally contains at least 0.1 mmol/kg, more preferably at least 0.5 mmol/kg, particularly preferably at least 1 mmol/kg, but preferably no more than 10 mmol/kg, particularly preferably no more than 6 mmol/kg of a depolarizer selected from nitrate ions, nitrite ions, nitroguanidine, N-methylmorpholine N-oxide, hydrogen peroxide in free or bound form, hydroxylamine in free or bound form, reducing sugars, preferably selected from nitrite ions, nitroguanidine, hydroxylamine in free or bound form, hydrogen peroxide in free or bound form, particularly preferably selected from nitrite ions.
• a depolarizer selected from nitrate ions, nitrite ions, nitroguanidine, N-methylmorpholine N-oxide, hydrogen peroxide in free or bound
• the rinsing stage can take place in a plurality of successive rinsing steps if it is ensured that the respective rinsing solutions (II) each have a pH in the range of 5.0 to 10.0 and a concentration of compounds of the elements Zr and/or Ti dissolved in water that is reduced at least by a factor of 5 in comparison with the aqueous conversion solution (I) and contain less than 0.25 mmol/kg, preferably less than 0.10 mmol/kg, particularly preferably less than 0.05 mmol/kg of free fluoride.
• the contacting with the respectively provided rinsing solution in the rinsing stage of method step (ii) is carried out by dipping and/or spraying, preferably dipping and spraying, wherein dipping is preferably carried out first and then spraying.
• the conversion of the metal surfaces of the component brought about in the second conversion stage serves, as has already been explained, primarily for the post-passivating deposition of oxidic/hydroxidic Zr and/or Ti compounds, so that, for reasons of process economy, but also for reliable compliance with the process window, relatively few active components of Zr and/or Ti in the conversion solution of the second conversion stage can be advantageous for optimum corrosion protection properties of the conversion layer constructed sequentially in the method according to the invention.
• the proportion of compounds of the elements Zr and/or Ti dissolved in water is less than 1.00 mmol/kg, preferably less than 0.80 mmol/kg, more preferably less than 0.70 mmol/kg, particularly preferably less than 0.60 mmol/kg.
• an amount of free fluoride is optional and it should be noted that the downstream conversion stage should not be set to be too mordanting at the same time in order to prevent the formation of local defects in the conversion coating. Nevertheless, a small amount of free fluoride may be useful for the cementation of the copper ions and the accelerated post-passivating deposition of oxidic/hydroxidic Zr and/or Ti for a short process time window.
• the proportion of free fluoride is less than 3.00 mmol/kg, preferably less than 2.50 mmol/kg, particularly preferably less than 2.00 mmol/kg, but preferably at least 0.1 mmol/kg, more preferably at least 0.2 mmol/kg, to support the increase in the coating on Zr and/or Ti.
• Suitable sources of free fluoride in the second conversion stage in method step i) of the method according to the invention are identical to those which are mentioned in connection with the first conversion stage.
• Corrosion protection and paint adhesion which are not sufficiently achieved until the second conversion stage, can be optimized by the amount of copper ions contained in the conversion solution (III). It is found that in the conversion solution (III) of the second conversion stage in method step iii), preferably more than 40 ⁇ mol/kg, particularly preferably more than 50 ⁇ mol/kg, should be contained. However, for reasons of process economy and for avoiding massive cementation of metallic copper, in particular when components are additionally pretreated with surfaces of zinc, it is preferred if no more than 500 ⁇ mol/kg, particularly preferably no more than 300 ⁇ mol/kg, and very particularly preferably no more than 200 ⁇ mol/kg of copper ions dissolved in water are contained in the conversion solution (II). Suitable sources of copper ions dissolved in water are water-soluble salts, such as copper nitrate (Cu(NO 3 ) 2 ), copper sulfate (CuSO 4 ) and copper acetate (Cu(CH 3 COO) 2 ).
• the anti-corrosion pre-treatment of the method according to the invention relates to a method execution for providing an amorphous conversion coating based on oxidic/hydroxidic compounds of the elements Zr and/or Ti, which provides an excellent paint adhesion primer for subsequently applied paint systems. Accordingly, it is preferred according to the invention if, after the method step (iii) with an intermediate rinsing step, but preferably without an intermediate drying step, a coating of the components is carried out using a paint system, preferably an electrodeposition coating, particularly preferably a cathodic electrodeposition coating.
• a rinsing step is used exclusively for the complete or partial removal of soluble residues, particles and active components that are carried over by adhering to the component from the previous wet-chemical method step (iii), from the component to be painted, without metal-element-based or semi-metal-element-based active components, which are already consumed merely by bringing the metal surfaces of the component into contact with the rinsing liquid, being contained in the rinsing liquid itself.
• the rinsing liquid can simply be municipal water or deionized water, or, if necessary, a rinsing liquid that contains surface-active compounds to improve the wettability with the rinsing liquid, which are preferably nonionic surfactants that, in the case of a subsequent electrodeposition coating to improve coverage, are in turn selected in particular from alkoxylated alkyl alcohols and/or alkoxylated fatty amines, which are ethoxylated and/or propoxylated, wherein the number of alkylene oxide units is preferably in total no more than 20, more preferably no more than 16, but more preferably at least 4, particularly preferably at least 8, wherein the alkyl group preferably comprises at least 10 carbon atoms, more preferably at least 12 carbon atoms, wherein an HLB value is realized in the range of 12 to 16, which is calculated as follows:
• a drying step in this context is a drying of the components caused by controllable technical precautions, for example by supplying heat or by means of directed air supply.
• the contacting of the aqueous solutions (I)-(III) in method steps (i)-(iii) with the components or surfaces of steel and/or iron is not selective for the success of the method according to the invention, so that conventional methods, such as dipping, spraying and splashing, are preferred.
• the method according to the invention is well suited for the anti-corrosion pre-treatment in series of materials composed of different metallic materials, the components of the series preferably also having surfaces of zinc and/or aluminum in addition to the surfaces of steel and/or iron.
• suitable metallic materials whose surfaces can be subjected to corrosion protection in the method according to the invention are zinc, electrolytic (ZE), hot-dip galvanized (Z) and alloy-galvanized (ZA), (ZF) and (ZM), and aluminum-coated (AZ), (AS) strip steel, as well as the light metals aluminum and magnesium and their alloys.
• the proportion of free fluoride was adjusted by means of an aqueous solution of ammonium bifluoride and the adjustment of the pH with ammonium bicarbonate.
• the pre-treated and electro-dip coated sheets were then aged for 6 weeks over 30 cycles according to the VW PV 1210 alternating climate test and the scribe delamination after aging was determined.

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• 2021
  • 2021-07-02 EP EP21183374.4A patent/EP4112773A1/de not_active Withdrawn
• 2022
  • 2022-06-30 EP EP22741234.3A patent/EP4363632A2/de active Pending
  • 2022-06-30 CN CN202280046241.2A patent/CN117580973A/zh active Pending
  • 2022-06-30 KR KR1020237045040A patent/KR20240025553A/ko unknown
  • 2022-06-30 CA CA3225205A patent/CA3225205A1/en active Pending
  • 2022-06-30 WO PCT/EP2022/068099 patent/WO2023275270A2/de active Application Filing
• 2023
  • 2023-12-18 US US18/543,174 patent/US20240124982A1/en active Pending

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