EP4363632A2 - Procédé de construction séquentielle d'une couche de conversion sur des composants présentant des surfaces en acier - Google Patents

Procédé de construction séquentielle d'une couche de conversion sur des composants présentant des surfaces en acier

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Publication number
EP4363632A2
EP4363632A2 EP22741234.3A EP22741234A EP4363632A2 EP 4363632 A2 EP4363632 A2 EP 4363632A2 EP 22741234 A EP22741234 A EP 22741234A EP 4363632 A2 EP4363632 A2 EP 4363632A2
Authority
EP
European Patent Office
Prior art keywords
mmol
conversion
particularly preferably
iii
stage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22741234.3A
Other languages
German (de)
English (en)
Inventor
Jan-Willem Brouwer
Frank-Oliver Pilarek
Fernando Jose RESANO ARTALEJO
Kristof WAPNER
Sebastian SINNWELL
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Henkel AG and Co KGaA
Original Assignee
Henkel AG and Co KGaA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Henkel AG and Co KGaA filed Critical Henkel AG and Co KGaA
Publication of EP4363632A2 publication Critical patent/EP4363632A2/fr
Pending legal-status Critical Current

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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
    • C23C22/78—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
    • C23C22/05—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
    • C23C22/73—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 present invention relates to a method for the anti-corrosion pretreatment of a large number of components in series, in which the components in the series are at least partially composed of iron and/or steel and in which the components in the series each first undergo a first conversion stage, followed by a rinsing stage and a the subsequent second conversion stage, with acidic aqueous conversion solutions based on compounds of the elements Zr and/or Ti dissolved in water being brought into contact with the components in the conversion stages and copper ions also being contained in the conversion solution of the second conversion stage.
  • Controlled layer formation and the growth of coatings that are as defect-free as possible is of great importance, particularly in the case of amorphous thin layers, such as those resulting from the conversion treatment of acidic aqueous solutions containing water-soluble compounds of the elements Zr and/or Ti.
  • EP 1 455 002 A1 therefore reports that even reducing the proportion of fluorides in the conversion coating can lead to improved corrosion behavior and paint adhesion to a subsequently applied electrophoretic paint.
  • EP 1 455 002 A1 proposes adding magnesium, calcium, a Si-containing compound, zinc or copper to the conversion solution and alternatively, or in combination, drying the conversion coating or a post-rinse with an alkaline aqueous composition. Furthermore, there are efforts in the prior art to improve the quality of the conversion coating via a sequential build-up of the coating.
  • EP 2 318 566 A1 shows that cascading rinsing water from the conversion treatment back 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 that provide good protection against corrosion, particularly on steel surfaces.
  • EP 2318 566 A1 a first low-grade conversion of the surface takes place in the pre-rinse, which is advantageous for the subsequent build-up of the actual conversion layer.
  • EP 2971 234 A1 a sequential build-up of layers by conversion in successive wet-chemical individual steps carried out independently of one another is used to improve paint adhesion on appropriately pretreated steel surfaces.
  • the present task is to establish alternative methods for providing conversion coatings that are as defect-free as possible for a large number of metals, which then have improved protection against corrosive paint migration after the paint layer has been built up.
  • the process should be as resource-saving as possible and particularly suitable for the treatment of components in series.
  • a significant improvement in corrosion protection and paint adhesion, at least on the surfaces of steel and/or iron, should also be achieved in a stable manner during the pretreatment of a series of components to improve the process quality.
  • This object is achieved by a method for sequentially building up a conversion coating in two treatment steps, which are interrupted by a rinsing step, the conversion solutions each containing water-soluble compounds of the elements Zr and/or Ti and copper ions also being contained in the second conversion step.
  • the present invention relates to a method for the anti-corrosion pretreatment of a large number of components in series, in which the components in the series are at least partially composed of iron and/or steel and in which the components in the series each have the successive method steps i) - iii) run through and at least the surfaces of iron and/or steel of the components are successively brought into contact with the respective aqueous solutions (l)-(lll): i) First conversion stage providing an aqueous conversion solution (I) which has a pH in the range from 2.5 to 5.0, containing at least 0.10 mmol/kg of compounds of the elements Zr and/or Ti dissolved in water and free fluoride; ii) rinsing stage providing an aqueous rinsing solution (II) which has a pH in the range from 5.0 to 10.0 and a concentration of compounds of the elements dissolved in water which is reduced by a factor of at least 5 compared to the aqueous conversion solution (I).
  • second conversion stage providing an aqueous conversion solution (III) which has a pH in the range from 2.5 to 5.0, containing at least 0.10 mmol/kg of compounds of the elements Zr and/or Ti dissolved in water and at least 15 pmol/kg of copper ions dissolved in water.
  • a corrosion-protective pretreatment of the components in series is present when a large number of components are brought into contact with the treatment solution provided in the respective treatment stages of the method according to the invention and usually stored in system tanks, the contacting of the individual components being sequential and thus separated in time.
  • the system tank is the container in which the treatment solution is located for the purpose of anti-corrosion pre-treatment in series.
  • the pretreatment of a component composed of a metallic material in particular the surfaces of the iron and steel materials to be subjected to the pretreatment in the method according to the invention, then all materials are included that the respective element to more than 50 at.% included.
  • An anti-corrosion pre-treatment always affects the surfaces of the component and thus the metallic materials.
  • the material can be a uniform material or a coating.
  • galvanized types of steel consist both of steel and of zinc, whereby surfaces of steel can be exposed on the cut edges and ground-through points, for example of an automobile body made of galvanized steel, and the steel material can then be pretreated according to the invention.
  • the concentration of an active component or compound is specified as the amount of substance per kilogram, this is the amount of substance based on the weight of the respective total composition.
  • the components pretreated according to the present invention can be any three-dimensional structure of any shape and design that originates from a manufacturing process, in particular semi-finished products such as strips, sheets, rods, tubes, etc. and composite structures assembled from the aforementioned semi-finished products, in particular Automobile bodies, the semi-finished products preferably being connected to one another by gluing, welding and/or flanging to form a composite structure.
  • a solution (I)-(III) is considered to be “provided” within the meaning of the process according to the invention if it is either stored or kept as defined in the respective treatment stage (i)-(iii) for the bringing into contact or upon contacting is realized as defined.
  • the multi-stage pretreatment according to the present invention provides, compared to 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 one-stage conversion layer formation") defect-free conversion layers with low Fluoride content and a significantly reduced tendency to corrosive infiltration of a subsequently applied paint system.
  • the combination of a first conversion stage with a second conversion stage that takes place after the rinsing stage in a conversion solution containing copper ions dissolved in water is essential 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 , which contains essentially 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, especially not for a sufficient performance in terms of corrosion protection on the steel and/or iron surfaces of the components of the series.
  • the amount of free fluoride in the respective stages of the pretreatment according to the invention is to be determined potentiometrically at 20° C. in the respective solution provided after calibration with fluoride-containing buffer solutions without pH buffering using a fluoride-sensitive measuring electrode.
  • the formation of the conversion layer in method steps i) and iii) takes place by means of conversion solutions which bring about an amorphous oxidic/hydroxidic coating based on the elements Zr and/or Ti and correspondingly contain compounds of the elements Zr and/or Ti dissolved in water.
  • conversion solutions which bring about an amorphous oxidic/hydroxidic coating based on the elements Zr and/or Ti and correspondingly contain compounds of the elements Zr and/or Ti dissolved in water.
  • dissolved in water includes molecularly dissolved species and compounds that dissociate in aqueous solution to form hydrated ions.
  • Typical representatives of these compounds are titanyl sulfate (TiO(SC>4)), titanyl nitrate (TiO(NC>3)2) and/or hexafluorotitanic acid (H2T 6) and its salts or ammonium zirconium carbonate ((NH4)2ZrO(CC>3)2 ) and/or hexafluorozirconic acid (H2ZrF6) and its salts.
  • the compounds dissolved in water in the conversion stages are preferably selected from fluoroacids and/or fluorocomplexes of the elements Zr and/or Ti convey.
  • the pH of the conversion solution is not too acidic, in order to keep the pickling rate as low as possible when growing the conversion layer, particularly in the first conversion stage.
  • the pH is above 3.0, particularly preferably above 3.5, particularly preferably above 4.0, but preferably below 4.5, since otherwise the precipitation of poorly soluble hydroxides of the elements Zr and/or Ti in the interior of the solution in the series treatment of a large number of components can only be kept under control within a narrow process window.
  • a process according to the invention is preferred in which the contacting with the conversion solution (I) in the first conversion stage in process step (i) takes place for at least a period of time for which a layer coverage of at least 20 mg/m 2 is brought about, but the contacting preferably does not continue for so long that a layer coverage of more than 150 mg/m 2 , more preferably more than 100 mg/m 2 , entirely particularly preferably more than 80 mg/m 2 in each case based on the elements Zr and/or Ti.
  • the bringing into contact with the Conversion solution (III) in the second conversion stage in process step (iii) does not last so long that the layer coverage increases by more than 15 mg/m 2 , particularly preferably by more than 12 mg/m 2 , very particularly preferably by more than 10 mg/m 2 on the surfaces of steel and/or iron, but the bringing into contact is preferably at least for such a period of time that the layer coverage on these surfaces is reduced by at least 2 mg/m 2 in each case based on the elements Zr and/or Ti is increased.
  • the layer structure in the conversion stages of the method according to the invention for the anti-corrosion pretreatment is optimally matched to one another.
  • the treatment time required for this ie the duration of contact with the conversion solution at a temperature in the range of 10-60° C., should be in the range from 10 seconds to 300 seconds.
  • a method is preferred according to the invention in which in the conversion solution (I) of the first conversion stage in process step i) the proportion of compounds of the elements Zr and/or Ti dissolved in water is preferably at least 0.15 mmol/kg, particularly preferably at least 0.25 mmol/kg, particularly preferably at least 0.30 mmol/kg.
  • the contents of compounds of the elements Zr and/or Ti dissolved in water should be well below 10.0 mmol/kg, particularly preferably below 5.0 mmol/kg.
  • a proportion of free fluoride is necessary in any case, but this depends on the type and surface properties of the metallic substrates, especially steel substrates, and the required pickling rate. It is fundamentally advantageous and therefore preferred according to the invention if the proportion of free fluoride in the conversion solution (I) of the first conversion stage in process step i) 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. However, for reasons of process economy and to prevent the formation of rust on the surfaces of steel and/or iron, especially after the rinsing stage, the proportion of free fluoride should preferably be less than 8.0 mmol/kg, more preferably less than 6.0 mmol/kg. kg, most preferably less than 5.0 mmol/kg.
  • V Me/mM where F / mM and Me / mM represent the free fluoride (F) or reduced zirconium and/or titanium concentration (Me) reduced by the unit of 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 for free fluoride in the first conversion stage in process step i) of the process according to the invention are hydrofluoric acid and its water-soluble salts, such as ammonium bifluoride and sodium fluoride, and complex fluorides of the elements Zr, Ti and/or Si, in particular complex fluorides of the element Si.
  • the source of free fluoride in a phosphating according to the second aspect of the present invention is therefore preferably selected from hydrofluoric acid and its water-soluble salts and/or complex fluorides of the elements Zr, Ti and/or Si.
  • Hydrofluoric acid salts are water-soluble in the context of the present invention if their solubility in deionized water (K ⁇ IpScrrr 1 ) at 60° C. is at least 1 g/L calculated as F.
  • the rinsing stage in process step ii) of the process according to the invention for sequential conversion coating serves to completely or partially remove or dilute soluble residues, particles and active components that are carried over from the previous wet-chemical process step i) adhering to the component.
  • the removal of soluble residues should also specifically cause the soluble fluoride species contained in the conversion coating and in this way condition 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 essentially does not have to contain any active components based on metallic or semi-metallic elements, which are consumed by deposition simply by bringing the metallic surfaces of the component into contact with the rinsing liquid.
  • the rinsing liquid can be city water or deionized water or, if necessary, a rinsing liquid that also contains redox-active compounds ("depolarizers") to optimize the conditioning of the metal surface accessible in point defects or surface-active compounds such as nonionic surfactants to improve the wettability with the rinsing solution or may contain anionic surfactants.
  • Essential for the fulfillment of the purpose of the rinsing stage is therefore initially only that the aqueous rinsing solution (II) provided in the rinsing stage has a compared to the aqueous conversion solution (I) by a factor of at least 5, preferably at least a factor of 10, particularly preferably at least has a concentration of compounds of the elements Zr and/or Ti dissolved in water that is reduced by a factor of 20, very particularly preferably at least by a factor of 50, and in particular less than 0.25 mmol/kg, preferably less than 0.10 mmol/kg 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 contains.
  • the thorough reduction of soluble fluoride species in the conversion coating can be achieved by bringing them into contact with rinsing solutions which have a reduced concentration of compounds of the elements Zr and/or dissolved in water diluted by a factor of more than 5, e.g. or Ti, can also be achieved in that the rinsing stage comprises several rinsing steps in direct succession, but preferably no more than three rinsing steps for reasons of process economy, with rinsing solutions (II) which have at least a factor of 5 reduced concentration of compounds dissolved in water containing the elements Zr and/or Ti.
  • the rinsing solution(s) (II) in the rinsing stage is less than 50 pmol/kg, preferably less than 15 pmol/kg in total, of metal ions of the elements copper dissolved in water,
  • the pH of the rinsing solution is in the range from 5.0 to 10.0.
  • alkaline rinsing solutions can be disadvantageous in that alkalinity is carried into the second conversion stage, which has to be compensated for there by re-sharpening with acidic substances and there also promotes the precipitation of active components and thus the formation of sludge.
  • the aqueous rinsing solution (II) preferably at least the rinsing solution of the last rinsing step of the rinsing stage in process step (ii)
  • the aqueous rinsing solution (II) of the rinsing stage in method step (ii) therefore additionally contains at least 0.1 mmol/kg, particularly preferably at least 0.5 mmol/kg, particularly preferably at least 1 mmol/kg 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 form,
  • the rinsing stage can be carried out in several successive rinsing steps insofar as it is ensured that the respective rinsing solutions (II) each have a pH in the range from 5.0 to 10.0 and, compared to the aqueous conversion solution (I), at least by the factor 5 has a reduced concentration of compounds of the elements Zr and/or Ti dissolved in water and contains 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 bringing into contact in the rinsing stage of process step (ii) with the rinsing solution provided in each case takes place by dipping and/or spraying, preferably dipping and spraying, with preferably first dipping and then spraying.
  • the conversion of the metal surfaces of the component brought about in the second conversion stage is primarily used for the post-passivation deposition of oxidic/hydroxidic Zr and/or Ti compounds, so that for reasons of process economy, but also to ensure compliance with the process window for optimal corrosion protection properties the conversion layer built up sequentially in the method according to the invention, relatively few active components of Zr and/or Ti in the conversion solution of the second conversion stage can be advantageous.
  • a process according to the invention is preferred in which the proportion of compounds of the elements Zr and/or Ti dissolved in water in the conversion solution (III) of the second conversion stage in process step iii) is less than 1.00 mmol/kg, preferably less than 0.80 mmol/kg, particularly 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 considered that the downstream conversion stage should not be overly caustic to prevent the formation of local defects in the conversion coating. Nevertheless, a small amount of free fluoride can be useful for the cementation of the copper ions and the accelerated post-passivation deposition of oxidic/hydroxidic Zr and/or Ti for a short process time window.
  • the proportion of free fluoride in the conversion solution (III) of the second conversion stage in process step iii) 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 assist in increasing the layer coverage of Zr and/or Ti.
  • Suitable sources for free fluoride in the second conversion stage in process step i) of the process according to the invention are identical to those mentioned in connection with the first conversion stage.
  • the corrosion protection and paint adhesion that is only brought about adequately with the second conversion stage can be optimized via the amount of copper ions contained in the conversion solution (III).
  • the conversion solution (III) of the second conversion stage in process step iii) should preferably contain more than 40 pmol/kg, particularly preferably more than 50 pmol/kg.
  • the conversion solution (II) it is preferred if in the conversion solution (II) not more than 500 pmol / kg, particularly preferably not more than 300 pmol/kg and very particularly preferably not more than 200 pmol/kg of copper ions dissolved in water are present.
  • 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 pretreatment of the method according to the invention relates to a method of providing an amorphous conversion coating based on oxidic/hydroxidic compounds of the elements Zr and/or Ti, which imparts an excellent paint primer to subsequently applied paint systems. Accordingly, it is preferred according to the invention if after process step (iii) with an intermediate rinsing step, but preferably without an intermediate drying step, the components are coated with a coating system, preferably electrocoating, particularly preferably cathodic electrocoating.
  • a rinsing step in this context is used exclusively for the complete or partial removal of soluble residues, particles and active components, which are carried over from the previous wet-chemical process step (iii) adhering to the component, from the component to be painted, without the rinsing liquid itself containing active components based on metallic or semi-metallic elements that are consumed simply by bringing the metallic surfaces of the component into contact with the rinsing liquid.
  • the rinsing liquid can only be city water or deionized water or, if necessary, also represent a rinsing liquid which contains surface-active compounds, preferably non-ionic surfactants, to improve the wettability with the rinsing liquid which in turn are selected in particular from alkoxylated alkyl alcohols and/or alkoxylated fatty amines which are ethoxylated and/or propoxylated in the case of subsequent electrocoating to improve the throwing power of the paint, the total number of alkylene oxide units preferably not being greater than 20, particularly preferably is not greater than 16, but is particularly preferably at least 4, particularly preferably at least 8, with the alkyl group preferably comprising at least 10 carbon atoms, particularly preferably at least 12 carbon atoms, with an HLB value in the range from 12 to 16 being realized, which is like is calculated as follows:
  • HLB 20 (1-Mi/M) with Mi: molar mass of the lypophilic group of the nonionic surfactant
  • M molar mass of the nonionic surfactant.
  • a drying step in this context is drying of the components brought about by controllable technical precautions, e.g. by supplying heat or directed air supply.
  • the contacting of the aqueous solutions (I) - (III) in the process steps (i) - (iii) with the components or surfaces of steel and / or iron is not selective for the success of the method, so that conventional methods such as dipping, spraying, spraying and gushing are preferred.
  • the duration of the bringing into contact in the respective treatment stages which is preferably in the range of 10-300 seconds
  • the temperature of the conversion solutions (I)-(II) during the bringing into contact preferably being in the range of 10-60°C, particularly preferably in the range of 25-55°C, very particularly preferably in the range of 30-50°C.
  • the method according to the invention is well suited for the anti-corrosion pretreatment in series of materials composed of different metallic materials
  • the components of the series preferably also surfaces of zinc and/or aluminum in addition to the surfaces of steel and/or iron exhibit.
  • Suitable metallic materials whose surfaces can be pre-treated to protect against corrosion in the process according to the invention are, in addition to steel and iron, 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. Examples:
  • the proportion of free fluoride was adjusted in each case by means of an aqueous solution of ammonium bifluoride and the pH value was adjusted with ammonium bicarbonate.
  • the pretreated and electrocoated metal sheets were then exposed to 30 cycles for 6 weeks in accordance with the VW PV 1210 alternating climate test, and the delamination at the scribe was determined after exposure.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Electrochemistry (AREA)
  • Chemical Treatment Of Metals (AREA)

Abstract

La présente invention concerne un procédé de pré-traitement anticorrosion d'une pluralité de composants en série, les composants de la série étant composés au moins en partie de fer et/ou d'acier et les composants de la série traversant chacun tout d'abord une première étape de conversion suivie d'une étape de rinçage directement suivie d'une deuxième étape de conversion. Au cours des étapes de conversion, des solutions de conversion aqueuses acides respectives à base de composés des éléments Zr et/ou Ti dissous dans l'eau sont mises en contact avec les composants, et des ions cuivre supplémentaires sont contenus dans la solution de conversion de la deuxième étape de conversion.
EP22741234.3A 2021-07-02 2022-06-30 Procédé de construction séquentielle d'une couche de conversion sur des composants présentant des surfaces en acier Pending EP4363632A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP21183374.4A EP4112773A1 (fr) 2021-07-02 2021-07-02 Procédé de construction séquentielle d'une couche de conversion sur des composants comprenant des surfaces en acier
PCT/EP2022/068099 WO2023275270A2 (fr) 2021-07-02 2022-06-30 Procédé de construction séquentielle d'une couche de conversion sur des composants présentant des surfaces en acier

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EP4363632A2 true EP4363632A2 (fr) 2024-05-08

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EP21183374.4A Withdrawn EP4112773A1 (fr) 2021-07-02 2021-07-02 Procédé de construction séquentielle d'une couche de conversion sur des composants comprenant des surfaces en acier
EP22741234.3A Pending EP4363632A2 (fr) 2021-07-02 2022-06-30 Procédé de construction séquentielle d'une couche de conversion sur des composants présentant des surfaces en acier

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US (1) US20240124982A1 (fr)
EP (2) EP4112773A1 (fr)
JP (1) JP2024524451A (fr)
KR (1) KR20240025553A (fr)
CN (1) CN117580973A (fr)
CA (1) CA3225205A1 (fr)
WO (1) WO2023275270A2 (fr)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10110834B4 (de) * 2001-03-06 2005-03-10 Chemetall Gmbh Verfahren zur Beschichtung von metallischen Oberflächen und Verwendung der derart beschichteten Substrate
JP4526807B2 (ja) 2002-12-24 2010-08-18 日本ペイント株式会社 塗装前処理方法
DE102008038653A1 (de) 2008-08-12 2010-03-25 Henkel Ag & Co. Kgaa Sukzessive korrosionsschützende Vorbehandlung von Metalloberflächen in einem Mehrstufenprozess
JP2014504333A (ja) * 2010-12-07 2014-02-20 日本パーカライジング株式会社 ジルコニウム、銅、及び金属キレート化剤を含有する金属前処理用組成物、並びに金属基材の関連するコーティング
WO2013033372A1 (fr) * 2011-09-02 2013-03-07 Ppg Industries Ohio, Inc. Procédé de phosphatation au zinc en deux étapes
US9303167B2 (en) 2013-03-15 2016-04-05 Ppg Industries Ohio, Inc. Method for preparing and treating a steel substrate
EP4041937A1 (fr) * 2019-10-10 2022-08-17 PPG Industries Ohio Inc. Systèmes et procédés de traitement d'un substrat

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Publication number Publication date
EP4112773A1 (fr) 2023-01-04
WO2023275270A3 (fr) 2023-03-09
KR20240025553A (ko) 2024-02-27
JP2024524451A (ja) 2024-07-05
WO2023275270A2 (fr) 2023-01-05
US20240124982A1 (en) 2024-04-18
CA3225205A1 (fr) 2023-01-05
CN117580973A (zh) 2024-02-20

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