EP3456864B1 - Two stage pre-treatment of aluminium, in particular aluminium casting alloys, comprising a pickle and a conversion treatment - Google Patents

Two stage pre-treatment of aluminium, in particular aluminium casting alloys, comprising a pickle and a conversion treatment Download PDF

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Publication number
EP3456864B1
EP3456864B1 EP17191578.8A EP17191578A EP3456864B1 EP 3456864 B1 EP3456864 B1 EP 3456864B1 EP 17191578 A EP17191578 A EP 17191578A EP 3456864 B1 EP3456864 B1 EP 3456864B1
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EP
European Patent Office
Prior art keywords
pickling solution
brought
contact
solution
water
Prior art date
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Application number
EP17191578.8A
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German (de)
French (fr)
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EP3456864A1 (en
Inventor
Volker GEICK
Kathrin SCHÄUBLE
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Henkel AG and Co KGaA
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Henkel AG and Co KGaA
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Priority to HUE17191578A priority Critical patent/HUE048447T2/en
Application filed by Henkel AG and Co KGaA filed Critical Henkel AG and Co KGaA
Priority to ES17191578T priority patent/ES2767852T3/en
Priority to PL17191578T priority patent/PL3456864T3/en
Priority to EP17191578.8A priority patent/EP3456864B1/en
Priority to MX2020001673A priority patent/MX2020001673A/en
Priority to CN201880060188.5A priority patent/CN111094624B/en
Priority to KR1020207007534A priority patent/KR102538202B1/en
Priority to PCT/EP2018/067027 priority patent/WO2019052701A1/en
Publication of EP3456864A1 publication Critical patent/EP3456864A1/en
Application granted granted Critical
Publication of EP3456864B1 publication Critical patent/EP3456864B1/en
Priority to US16/817,044 priority patent/US11499237B2/en
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    • CCHEMISTRY; METALLURGY
    • C23COATING 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
    • C23CCOATING 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
    • C23C22/00Chemical 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
    • C23C22/05Chemical 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
    • C23C22/06Chemical 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
    • C23C22/34Chemical 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
    • CCHEMISTRY; METALLURGY
    • C23COATING 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
    • C23CCOATING 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
    • C23C22/00Chemical 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
    • C23C22/78Pretreatment of the material to be coated
    • C23C22/80Pretreatment of the material to be coated with solutions containing titanium or zirconium compounds
    • CCHEMISTRY; METALLURGY
    • C23COATING 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
    • C23CCOATING 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
    • C23C22/00Chemical 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
    • C23C22/82After-treatment
    • CCHEMISTRY; METALLURGY
    • C23COATING 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
    • C23GCLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/12Light metals
    • C23G1/125Light metals aluminium
    • CCHEMISTRY; METALLURGY
    • C23COATING 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
    • C23GCLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/14Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
    • C23G1/22Light metals
    • CCHEMISTRY; METALLURGY
    • C23COATING 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
    • C23CCOATING 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
    • C23C24/00Coating starting from inorganic powder

Definitions

  • the present invention relates to a process for the corrosion-protective treatment of components made of aluminum, in particular castings such as automobile rims, comprising a pretreatment stage and a subsequent coating.
  • the pretreatment step again includes a pickle based on sulfuric acid and phosphate-free aqueous solutions containing water-soluble compounds of the element Ti and at least one polybasic ⁇ -hydroxycarboxylic acid and a source of fluoride ions, the conversion treatment based on an acidic aqueous solution containing water-soluble compounds of the elements Zr and / or Ti is upstream.
  • the prior art discloses a multiplicity of pretreatment methods of components made of aluminum, in particular of aluminum casting, for imparting corrosion protection and as a paint adhesion base, which are based on a plurality of successive wet-chemical process steps.
  • the component is first subjected to a cleaning, which is a combination of surface-active and etching substances both for removing superficial contaminants originating from upstream fabrication stages, for example mold release agents, as well as for producing a reproducible component surface, which is necessary for the application of a homogeneous adhesion-promoting conversion layer , contains.
  • a cleaning which is a combination of surface-active and etching substances both for removing superficial contaminants originating from upstream fabrication stages, for example mold release agents, as well as for producing a reproducible component surface, which is necessary for the application of a homogeneous adhesion-promoting conversion layer , contains.
  • additional process steps may be required in order to obtain a substrate surface optimally conditioned for the conversion layer formation.
  • WO 94/28193 A1 It is known that a preservation of the aluminum surface produced after the cleaning and acid pickling or dewetting can be achieved for a subsequent permanent corrosion-protective pretreatment if the pickling already has passivating active components selected from water-soluble compounds of the elements Zr and / or Ti.
  • active components in the acidic pickling polyhydroxycarboxylic acids, such as gluconic acid, or polymers based on acrylates or derivatized vinylphenols are optional.
  • the after the WO 94/28193 A1 obtained passivation is intended to protect the surface against partial oxidation until the application of the permanent corrosion-protecting pretreatment and to preserve the largely homogenous chemical nature of the aluminum surface.
  • the semifinished product treated in this way can be subjected to further component production such as chipless machining, welding or forming without the occurrence of adverse effects on the immediately following applied permanent corrosion protection until the application of the permanent corrosion protection.
  • the object of the present invention is now to provide the operators of coating equipment for components made of aluminum and its alloys, in particular castings, a pretreatment stage based on the established process sequence of an acid pickling followed by a chromium-free conversion treatment based on the elements Zr and / or Ti built in the continuous operation of such a system, the bath life and maintenance intervals are extended over the prior art and ideally no caused by sludge maintenance of the pretreatment stage of the coating plant is required.
  • every measure suitable for avoiding sludge formation should be taken at the same time exerts no negative influence on the corrosion protection and the paint adhesion of the pre-treated in such a coating system components.
  • This object is achieved in a method for corrosion-protective treatment of aluminum-made components comprising a pretreatment stage and a subsequent coating, wherein the component in the pretreatment stage first with an aqueous sulfuric acid and phosphate-free pickling solution, the pH of 1 to 2.5, has a free acidity in points of at least 5 and at least one water-soluble compound of the element Ti; a source of fluoride ions and at least one polybasic ⁇ -hydroxycarboxylic acid, and then contacted with an aqueous conversion treatment solution having a pH of 1 to 3.5 and at least one water-soluble compound of the elements Zr and / or Ti becomes.
  • the pH denotes the negative decadic logarithm of the activity of the hydronium ions.
  • the pH is determined potentiometrically at 20 ° C. directly in the solution by means of pH-sensitive electrodes after two-point calibration with buffer solutions for the pH values of 4.01 and 7.01.
  • a compound is water soluble if its solubility in deionized water ( ⁇ ⁇ 1 ⁇ Scm -1 ) and at a temperature of 20 ° C is at least 1g / kg. All quantities in "g / kg" refer to the proportion of the respective component per kilogram of the respectively indicated reference solution.
  • an excellent paint adhesion is achieved which, surprisingly, also in the absence of phosphates and with high tolerance to aluminum ions in the stain, is based on the combination of the Ti and Zr coating applied in the multistage process.
  • the absence of phosphates and high tolerance to aluminum ions in the stain enable the pretreatment stage to produce no precipitates and therefore no sludge in continuous operation. This requires the presence of the polybasic ⁇ -hydroxycarboxylic acid.
  • Polybasic ⁇ -hydroxycarboxylic acids in the context of the present invention have at least two carboxylic acid groups and at least one hydroxyl group in ⁇ position to one of the carboxylic acid groups.
  • the at least one polybasic ⁇ -hydroxycarboxylic acid is selected from those compounds in which each carboxyl group has a hydroxyl group in the ⁇ - or ⁇ -position, and which furthermore preferably has not more than 8 carbon atoms.
  • Particularly preferred representatives of the polybasic ⁇ -hydroxycarboxylic acid are tartaric acid and / or citric acid, particularly preferably citric acid.
  • the proportion of polybasic ⁇ -hydroxycarboxylic acids in the pickling solution at least 0.1 g / kg, especially preferably at least 0.5 g / kg, especially
  • the proportion of polybasic ⁇ - Hydroxycarboxylic acids in the pickling solution therefore in a preferred process according to the invention not greater than 4 g / kg, more preferably not greater than 2 g / kg.
  • the positive effect of the mordant-containing water-soluble compounds of the element titanium in the presence of the source of fluoride ions on the subordinate conversion treatment is usually already achieved with small amounts in the range of a few milligrams of Ti per kilogram of mordant.
  • the proportion of water-soluble compounds of the element Ti in the pickling solution is preferably at least 0.04 g / kg, more preferably at least 0.1 g / kg. Above one gram of Ti per kilogram of pickling solution, no significant improvement in paint adhesion is obtained after the conversion treatment.
  • the pickling solution is preferably not more than 0.6 g / kg, more preferably not more than 0.3 g / kg in each case based on the element Ti of water-soluble compounds of the element Ti.
  • water-soluble compounds of the element Ti titanyl sulfate (TiO (SO 4 )), titanyl nitrate (TiO (NO 3 ) 2 ) and / or hexafluorotitanic (H 2 TiF 6 ) and their salts are well suited and therefore preferred in the pickling solution of the process according to the invention , particularly preferred is hexafluorotitanic acid and its salts.
  • a source of fluoride ions according to the invention is required for a sufficient stain of the aluminum-made component without a reproducible largely oxide-free surface can not be adjusted and the positive effect of containing in the stain water-soluble compounds of the element titanium on the paint adhesion does not apply can.
  • a source of fluoride ions in the context of the present invention is any water-soluble inorganic compound containing fluorine containing at least 100 mg / kg of fluoride ions as 0.1% by weight aqueous solution after TISAB buffering with an aliquot of the buffer. determined potentiometrically at 20 ° C by means of a fluoride ion-sensitive electrode according to DIN 38 405-D-4-1, released. An aliquot of the buffer results in a volume mixing ratio of buffer to aqueous solution containing the source of fluoride of 1: 1.
  • the TISAB Buffer (Total Lonic Strength Adjustment Buffer) is manufactured with a resolution of 58 g NaCl, 1 g of sodium citrate and 50 ml of glacial acetic acid in 500 ml of deionized water ( ⁇ ⁇ 1 ⁇ Scm -1 ) and setting a pH of 5.3 by means of 5 N NaOH and filling to a total volume of 1000 ml again with deionized water ( ⁇ ⁇ 1 ⁇ Scm -1 ).
  • the total fluoride content in the pickling solution is at least 0.02 g / kg, particularly preferably at least 0.05 g / kg, very particularly preferably at least 0.1 g / kg calculated as F.
  • the total fluoride content is determined in the context of the present invention by means of a fluoride ion-sensitive electrode according to DIN 38 405-D-4-1 as described above.
  • the proportion of free fluoride in the pickling solution is to be kept low for a moderate pickling rate of the aluminum material.
  • the proportion of free fluoride is therefore less than 10 mg / kg, more preferably less than 5 mg / kg each potentiostatically determined directly in the pickling solution at 20 ° C by means of calibrated fluoride-sensitive electrode.
  • Suitable sources of fluoride ions are, for example, ammonium bifluoride, sodium fluoride and / or complex fluorides, in particular hexafluorotitanic acid and its salts.
  • complex fluorides of the element Zr should not be included in the pickling solution since these are also likely to cause the surfaces of the aluminum-made component to adhere and therefore compete with the conditioning of the aluminum surfaces achieved by the water-soluble compounds of the element Ti.
  • the pickling solution therefore contains a total of less than 0.02 g / kg, more preferably less than 0.01 g / kg, most preferably less than 0.004 g / kg of water-soluble compounds of the element Zr calculated as Zr ,
  • the pickling solution preferably has a pH below 2.0 in a process according to the invention. This ensures on a regular basis that a sufficient stain can take place in the pretreatment stage.
  • the pickling solution has a free acid content of at least 6 points, so that a pickling removal which is largely independent of the type of aluminum material to be treated and sufficiently adequate for the subsequent conversion treatment is ensured, for example in the series treatment of different aluminum materials manufactured individual components or in the series treatment of individual components produced from a mix of different aluminum materials.
  • the free acid content in points should preferably not be greater than 10 in order to effect sufficient conditioning of the aluminum surfaces on the basis of the water-soluble compounds of Ti element contained in the pickling solution.
  • the free acid content in points is determined in the context of the present invention by diluting 10 ml of the pickling solution to 50 ml and titrating with 0.1 N sodium hydroxide solution to a pH of 3.6. The consumption of milliliters of caustic soda indicates the score.
  • the presence of a certain buffer capacity or a certain acidity has proven to be a stable process control in a series treatment.
  • the total acid content of importance and this is in the pickling solution of the method according to the invention preferably at least 12 points, but preferably not more than 18 points.
  • the total acid content is inventively determined analogously to the free acid with the difference that is titrated to a pH of 8.5.
  • An aqueous pickling solution is sulfuric if it contains sulfuric acid to adjust the pH and the proportion of other acids with a pKS 1 value of less than 2.5 for the first deprotonation step is less than 1 g / kg, more preferably less than 0 5 g / kg, more preferably less than 0.1 g / kg.
  • the pickling solution in the process according to the invention for preventing the precipitation of sparingly soluble salts and the film formation on the surfaces of the aluminum-made component is phosphate-free.
  • An aqueous pickling solution is phosphate-free if it contains less than 0.5 g / kg, preferably less than 0.1 g / kg, more preferably less than 0.05 g / kg of phosphates dissolved in water, calculated as PO 4 .
  • Particularly suitable nonionic surfactants are selected from alkoxylated alkyl alcohols, alkoxylated fatty amines and / or alkylpolyglycosides, particularly preferably from alkoxylated alkyl alcohols and / or alkoxylated fatty amines, particularly preferably from alkoxylated alkyl alcohols.
  • Alkoxylated alkyl alcohols and / or alkoxylated fatty amines are preferably end-capped, more preferably having an alkyl group, which in turn preferably has not more than 8 carbon atoms, more preferably not more than 4 carbon atoms.
  • the component in the process of the invention, it is advantageous for sufficient staining and conditioning of the aluminum surfaces, and therefore also preferred, for the component to be contacted with the pickling solution for a duration sufficient to contain at least 2 mg of aluminum per square meter of surface area contacted to pickle the component and particularly preferably also sufficient to produce a coating layer of at least 4 mg of titanium per square meter on the contacted surface of the component.
  • the pickling solution is also preferably adjusted for the observance of pretreatment-typical treatment times such that for a alloy according to EN AW-6014 (AIMg0.6Si0.6V) at 40 ° C in an unstirred pickling solution of the method according to the invention, a pickling rate of at least 15 mgm -2 s -1 based on the element aluminum results.
  • EN AW-6014 AIMg0.6Si0.6V
  • a conversion layer based on the elements Zr and / or Ti is applied in the method according to the invention.
  • a layer of at least 50 .mu.mol / m 2 preferably at least 100 .mu.mol / m 2 , more preferably at least 200 .mu.mol / m 2 , but preferably determined by not more than 500 .mu.mol / m 2 by X-ray fluorescence analysis (RFA) based on the sum of the elements Zr and Ti, and the components made of aluminum are therefore brought into contact with the conversion treatment solution for such a duration that a corresponding layer support is realized.
  • RFA X-ray fluorescence analysis
  • At least 0.1 mmol / kg more preferably at least 0.5 mmol / kg of water-soluble compounds of the elements Zr and / or Ti calculated as a corresponding amount of the elements Zr and / or Ti however, for economic reasons, preferably not more than 5 mmol / kg, more preferably not more than 3 mmol / kg.
  • Suitable representatives of water-soluble compounds are ammonium zirconium carbonate ((NH 4 ) 2 Zr (OH) 2 (CO 3 ) 2 ), titanyl sulfate (TiO (SO 4 )), zirconium sulfate (Zr (SO 4 ) 2 ), titanium nitrate (Ti (NO 3 ) 4 Zirconium nitrate (Zr (NO 3 ) 4 ), zirconyl nitrate (ZrO (NO 3 ) 2 ), titanyl nitrate (TiO (NO 3 ) 2 ), ammonium zirconium lactate (NH 4 Zr (C 3 H 5 O 3 ) 5 ), zirconium perchlorate ( Zr (ClO 4 ) 4 ), titanium perchlorate (Ti (ClO 4 ) 4 ), and / or hexafluorotitanic acid (H 2 TiF 6 ) or hexafluorozirconic acid (H 2
  • the molar ratio of the total content of water-soluble compounds of the elements Zr and Ti relative to the respective elements to the total fluoride content in the conversion treatment solution is at least zero , 1, more preferably at least 0.4. It has surprisingly been found that the use
  • the pH of the conversion treatment solution in the pretreatment stage is at least 1.8, more preferably at least 2.0.
  • the conversion treatment solution therefore contains a total of less than 0.1 g / kg of water-soluble compounds of the element chromium calculated as Cr.
  • the addition of phosphate ions to the conversion treatment solution is not advantageous, so that selbige in the process according to the invention is analogous to the pickling solution phosphate-free and therefore less than 0.5 g / kg, preferably less than 0.1 g / kg, more preferably less than 0 , 05 g / kg of phosphates dissolved in water, calculated as PO 4 .
  • Components made of aluminum which are treated in accordance with the present invention corrosion protection, are those whose metallic component consists of aluminum and / or aluminum alloys, in particular aluminum casting alloys, or is composed.
  • An alloy is an aluminum alloy in that it consists of at least 50 at.% Of the element Al.
  • Suitable components made of aluminum in the method according to the invention are for example selected from semi-finished products such as sheet metal, strip, coil or wire or from complex three-dimensional production objects such as rims for the automotive sector.
  • the components may be formed from strip material or sheets and / or joined together or made by casting.
  • the treatment of components made of cast aluminum alloys for example AA 6014, in particular rims for the automotive sector is preferred.
  • a pretreatment step in the sense of the present invention is a process step which is separate from the application of the paint finish and which comprises the process steps of pickling and conversion treatment which are separated from one another with the aid of liquid compositions in the form of the pickling liquor and each independently stored in system tanks Conversion treatment solution.
  • the components made of aluminum are pretreated in series in the pretreatment stage of the process according to the invention.
  • pretreatment in series involves contacting a plurality of components made of aluminum with the pickling and conversion treatment solution respectively stored in a system tank, without a complete exchange with a new batch of the following in each of the pretreatment of a single component made of aluminum System tanks of pre-treatment stage stockpiled pickling and conversion treatment solutions takes place.
  • the transition of the component from the stain into the conversion treatment takes place "directly".
  • a "rinsing step" in the sense of the present invention denotes a process which is intended solely to remove as far as possible active components from an immediately preceding wet-chemical treatment step, which are dissolved in a wet film adhering to the component, by means of a rinsing solution from the surface of the component. without replacing the active components to be removed by others. Active components are dissolved in water compounds that consume already by the mere contacting of the metallic surfaces of the component with the rinsing liquid.
  • the rinsing fluid can be city water.
  • the components to be treated in the process according to the invention originate from an upstream production process whose surfaces should therefore first be freed from impurities, such as mold release aids, in order to ensure good pickling.
  • the component is therefore supplied in the pretreatment stage before being brought into contact with the pickling solution to an alkaline degreasing, more preferably by contacting with an alkaline aqueous composition having a pH above 9, however, preferably below 12, and having a free alkalinity of at least 3 points, but preferably less than 6 points, and optionally containing surface active compounds, preferably selected from nonionic surfactants.
  • a rinsing step but preferably no drying step takes place.
  • the application of the cleaning, pickling and conversion treatment solution stored in the respective system tanks of the pre-treatment stage can be carried out by all methods known in the art, with immersion and spraying methods for bringing the aluminum made into contact
  • the spray method is particularly preferred as the type of application.
  • the coating following the pretreatment stage comprises the application of a composition comprising a chemically or physically hardening binder to form a cover layer on the pretreated and aluminum-made component, wherein the cover layer resulting from the coating in the dried or cured state has a layer thickness of preferably at least one micrometer , particularly preferably of at least 10 .mu.m, measured according to the wedge-cut method according to DIN 50986: 1979-03.
  • Suitable lacquers are autophoretic lacquers, electrodeposition lacquers, powder lacquers and liquid lacquers which can be applied by conventional means.
  • paints based on inorganic binders such as, for example, silicate or lime
  • paints based on organic binders can be used according to the invention.
  • the following application of lacquers based on organic binders, in particular those containing less than 10% by weight of organic solvent constituents, which have a boiling point below 150 ° C. at 1 bar, is particularly advantageous.
  • powder coatings are preferred, in particular those with binders based on epoxy resins, carboxyl- and hydroxyl-containing polyester resins and / or acrylate resins, each having an excellent paint adhesion to the pretreated according to the invention made of aluminum components.
  • the component made of aluminum can be subjected after the pretreatment and before the painting of a sink, which serves to remove an adhering to the surface wet film of the conversion solution before the paint is applied. Furthermore, it is usual and may therefore be preferred that the component is dried before the application of the paint. This is the case in particular when a powder coating is to be applied, for which a particularly good paint adhesion base is provided in the method according to the invention and therefore there is a preference.
  • the sludge-inhibiting effect of the polybasic ⁇ -hydroxycarboxylic acids is illustrated in Table 2, which assesses the sludge formation in a pickling solution according to the above process step II, but added a total of 1 g / kg of aluminum ions in the form of aluminum sulfate. From this table shows that an inhibition of sludge formation, ie the precipitation of aluminum and titanium salts, succeed in the presence of citric acid or tartaric acid.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Description

Die vorliegende Erfindung betrifft ein Verfahren zur korrosionsschützenden Behandlung von aus Aluminium gefertigten Bauteilen, insbesondere Gussteilen wie Automobilfelgen, umfassend eine Vorbehandlungsstufe und eine nachfolgende Lackierung. Die Vorbehandlungsstufe beinhaltet wiederum eine Beize auf Basis schwefelsaurer und phosphatfreier wässriger Lösungen enthaltend wasserlösliche Verbindungen des Elements Ti sowie mindestens eine mehrbasige α-Hydroxycarbonsäure und eine Quelle für Fluorid-Ionen, die einer Konversionsbehandlung auf Basis einer sauren wässrigen Lösung enthaltend wasserlösliche Verbindungen der Elemente Zr und/oder Ti vorgelagert ist.The present invention relates to a process for the corrosion-protective treatment of components made of aluminum, in particular castings such as automobile rims, comprising a pretreatment stage and a subsequent coating. The pretreatment step again includes a pickle based on sulfuric acid and phosphate-free aqueous solutions containing water-soluble compounds of the element Ti and at least one polybasic α-hydroxycarboxylic acid and a source of fluoride ions, the conversion treatment based on an acidic aqueous solution containing water-soluble compounds of the elements Zr and / or Ti is upstream.

Im Stand der Technik ist eine Vielzahl an Vorbehandlungsverfahren von aus Aluminium gefertigten Bauteilen, insbesondere von Aluminiumguss, zur Vermittlung eines Korrosionsschutzes und als Lackhaftgrund bekannt, die auf mehreren aufeinanderfolgenden nasschemischen Verfahrensschritten basieren. Üblicherweise wird das Bauteil dabei zunächst einer Reinigung unterzogen, die eine Kombination von oberflächenaktiven und beizenden Substanzen sowohl zur Entfernung von aus vorgelagerten Fabrikationsstufen stammenden oberflächlichen Verschmutzungen, beispielsweise Formtrennmitteln, als auch zur Erzeugung einer reproduzierbaren Bauteiloberfläche, die für die Aufbringung einer homogenen haftungsvermittelnden Konversionsschicht notwendig ist, enthält. Je nach Art der Reinigung können zwischengelagert weitere Verfahrensschritte erforderlich sein, um eine für die Konversionsschichtbildung optimal konditionierte Substratoberfläche zu erhalten. So wird in der die WO 2003/097899 A2 ein Verfahren für die Konversionsbehandlung von Aluminiumrädern offenbart, bei dem zwischen einer alkalischen Reinigung und Konversionsschichtbildung auf Basis einer sauren Zusammensetzung ein weiterer nasschemischer Schritt nach der Art einer Dekapierung durchgeführt wird, der der Entfernung alkalischer Rückstände und der nach der Reinigung verbleibenden Oxidschicht dient. Erst das auf diese Weise gereinigte und "dekapierte" Bauteil weist eine nahezu metallische Oberfläche und ist damit bestens konditioniert für die nachfolgende Konversionsschichtbildung.The prior art discloses a multiplicity of pretreatment methods of components made of aluminum, in particular of aluminum casting, for imparting corrosion protection and as a paint adhesion base, which are based on a plurality of successive wet-chemical process steps. Usually, the component is first subjected to a cleaning, which is a combination of surface-active and etching substances both for removing superficial contaminants originating from upstream fabrication stages, for example mold release agents, as well as for producing a reproducible component surface, which is necessary for the application of a homogeneous adhesion-promoting conversion layer , contains. Depending on the type of cleaning, additional process steps may be required in order to obtain a substrate surface optimally conditioned for the conversion layer formation. So in the the WO 2003/097899 A2 discloses a process for the conversion treatment of aluminum wheels, in which between alkaline cleaning and conversion layer formation based on an acidic composition, another wet chemical step is carried out in the manner of a pickling, which serves for the removal of alkaline residues and the remaining after cleaning oxide layer. Only the thus cleaned and "decanted" component has a nearly metallic surface and is thus optimally conditioned for the subsequent conversion layer formation.

Auch die internationale Offenlegungsschrift WO 00/68458 A1 stellt sich die Aufgabe einer möglichst effizienten Verfahrensabfolge zur korrosionsschützenden Vorbehandlung von aus Aluminium gefertigten Bauteilen. Hier offenbart ist ein dreistufiges Verfahren bestehend aus einer sauren Beize, einer Spüle und einer sauren Konversionsbehandlung auf Basis der Elemente Zr und/oder Ti, wobei die Spüle zwischen Beize und Konversionsbehandlung vorzugsweise aus mehreren Spülschritten besteht, innerhalb derer das Spülwasser kaskadenartig entgegen der Transportrichtung des Bauteils geführt wird.Also the international publication WO 00/68458 A1 the task of the most efficient process sequence possible for the corrosion-protective pretreatment of aluminum-made components. Disclosed herein is a three-stage process consisting of an acidic pickle, a sink and an acidic conversion treatment based on the elements Zr and / or Ti, wherein the sink between pickling and conversion treatment preferably consists of several rinsing steps exists, within which the rinse water is cascaded against the transport direction of the component.

Auch ist aus der WO 94/28193 A1 bekannt, dass eine Konservierung der nach der Reinigung und sauren Beize bzw. Dekapierung erzeugten Aluminiumoberfläche für eine nachfolgende permanente vor Korrosion schützende Vorbehandlung dann erzielt werden kann, wenn der Beize bereits passivierende Aktivkomponenten ausgewählt aus wasserlöslichen Verbindungen der Elemente Zr und/oder Ti beigefügt sind. Zusätzlich sind als Aktivkomponenten in der sauren Beize Polyhydroxycarbonsäuren, wie beispielsweise Gluconsäure, oder Polymere auf Basis von Acrylaten oder derivatisierten Vinylphenolen optional. Die nach der WO 94/28193 A1 erzielte Passivierung soll die Oberfläche bis zur Aufbringung der permanenten vor Korrosion schützenden Vorbehandlung vor partieller Oxidation schützen und eine Konservierung der weitestgehend homogenen chemischen Beschaffenheit der Aluminiumoberfläche leisten. Das auf diese Weise behandelte Halbzeug kann bis zur Aufbringung des permanenten Korrosionsschutzes der weiteren Bauteilfertigung wie dem spanlosen Bearbeiten, Schweißen oder dem Umformen unterworfen werden, ohne dass nachteilige Auswirkungen für den unmittelbar nachfolgenden aufgebrachten permanenten Korrosionsschutz zu befürchten sind.Also is from the WO 94/28193 A1 It is known that a preservation of the aluminum surface produced after the cleaning and acid pickling or dewetting can be achieved for a subsequent permanent corrosion-protective pretreatment if the pickling already has passivating active components selected from water-soluble compounds of the elements Zr and / or Ti. In addition, as active components in the acidic pickling polyhydroxycarboxylic acids, such as gluconic acid, or polymers based on acrylates or derivatized vinylphenols are optional. The after the WO 94/28193 A1 obtained passivation is intended to protect the surface against partial oxidation until the application of the permanent corrosion-protecting pretreatment and to preserve the largely homogenous chemical nature of the aluminum surface. The semifinished product treated in this way can be subjected to further component production such as chipless machining, welding or forming without the occurrence of adverse effects on the immediately following applied permanent corrosion protection until the application of the permanent corrosion protection.

Das Beizen umfasst nicht lediglich die Entfernung der Oxidschicht, sondern schließt üblicherweise auch das Beizen des aus Aluminium gefertigten Bauteils selbst ein. Dies ist regelmäßig erwünscht und notwendig, um eine homogene reproduzierbare metallische Oberfläche für die nachfolgende korrosionsschützende Konversionsbeschichtung bereitzustellen. Hier ergibt sich jedoch das Problem der Anreicherung von Aluminium-Salzen in der sauren Beize. Die hohe Aluminiumfracht ist ursächlich für die Ausfällung schwerlöslicher Salze insbesondere in Anwesenheit von in der sauren Beize enthaltenden passivierenden Aktivkomponenten auf Basis der Elemente Zr und/oder Ti. Die Ausfällungen führen im kontinuierlichen Betrieb einer Vorbehandlungsstufe zu Schlammbildung und Verkrustungen, die an bewegten Teilen der Beschichtungsanlage wie Ventilen für den Sprühauftrag oder Transportgestellen häufiger entfernt werden müssen. Damit ist eine wiederkehrende Wartung der Anlage erforderlich, die nicht im laufenden Betrieb der Anlage durchgeführt werden kann und üblicherweise den Austausch des gesamten Badvolumens erfordert, so dass auch die Badstandzeit erheblich verkürzt ist.Pickling not only involves removal of the oxide layer, but usually also includes pickling of the aluminum-made component itself. This is regularly desirable and necessary to provide a homogeneous reproducible metallic surface for the subsequent anti-corrosive conversion coating. Here, however, there is the problem of accumulation of aluminum salts in the acidic stain. The high aluminum load is the cause of the precipitation of sparingly soluble salts, especially in the presence of acidic pickling containing passivating active components based on the elements Zr and / or Ti. The precipitates lead in the continuous operation of a pretreatment stage to sludge formation and incrustations on moving parts of the coating plant how valves for spray application or transport racks need to be removed more frequently. Thus, a recurrent maintenance of the system is required, which can not be performed during operation of the system and usually requires the replacement of the entire bath volume, so that the bath life is significantly reduced.

Die vorliegende Erfindung stellt sich nun die Aufgabe den Betreibern von Beschichtungsanlage für aus Aluminium und seinen Legierungen gefertigten Bauteilen, insbesondere Formgussteilen, eine Vorbehandlungsstufe bereitzustellen, die auf der etablierten Prozessfolge einer sauren Beize gefolgt von einer chromfreien Konversionsbehandlung auf Basis der Elemente Zr und/oder Ti aufbaut, wobei im kontinuierlichen Betrieb einer solchen Anlage die Badstandzeiten und Wartungsintervalle gegenüber dem Stand der Technik verlängert sind und idealerweise keine durch Schlammbildung verursachte Wartung der Vorbehandlungsstufe der Beschichtungsanlage erforderlich ist. Gleichzeitig ist jedoch unabdingbar, dass jede für die Vermeidung der Schlammbildung geeignete Maßnahme gleichzeitig keinen negativen Einfluss auf den Korrosionsschutz und die Lackhaftung der in einer solchen Beschichtungsanlage vorbehandelten Bauteile ausübt.The object of the present invention is now to provide the operators of coating equipment for components made of aluminum and its alloys, in particular castings, a pretreatment stage based on the established process sequence of an acid pickling followed by a chromium-free conversion treatment based on the elements Zr and / or Ti built in the continuous operation of such a system, the bath life and maintenance intervals are extended over the prior art and ideally no caused by sludge maintenance of the pretreatment stage of the coating plant is required. At the same time, however, it is indispensable that every measure suitable for avoiding sludge formation should be taken at the same time exerts no negative influence on the corrosion protection and the paint adhesion of the pre-treated in such a coating system components.

Diese Aufgabe wird in einem Verfahren zur korrosionsschützenden Behandlung von aus Aluminium gefertigten Bauteilen umfassend eine Vorbehandlungsstufe und eine nachfolgende Lackierung gelöst, wobei das Bauteil in der Vorbehandlungsstufe zunächst mit einer wässrigen schwefelsauren und phosphatfreien Beizlösung, die einen pH-Wert von 1 bis 2,5, einen freien Säuregehalt in Punkten von zumindest 5 aufweist und mindestens eine wasserlösliche Verbindung des Elements Ti; eine Quelle für Fluorid-Ionen sowie mindestens eine mehrbasige α-Hydroxycarbonsäure enthält, und anschließend mit einer wässrigen Konversionsbehandlungslösung, die einen pH-Wert von 1 bis 3,5 und mindestens eine wasserlösliche Verbindung der Elemente Zr und/oder Ti enthält, in Kontakt gebracht wird.This object is achieved in a method for corrosion-protective treatment of aluminum-made components comprising a pretreatment stage and a subsequent coating, wherein the component in the pretreatment stage first with an aqueous sulfuric acid and phosphate-free pickling solution, the pH of 1 to 2.5, has a free acidity in points of at least 5 and at least one water-soluble compound of the element Ti; a source of fluoride ions and at least one polybasic α-hydroxycarboxylic acid, and then contacted with an aqueous conversion treatment solution having a pH of 1 to 3.5 and at least one water-soluble compound of the elements Zr and / or Ti becomes.

Der pH-Wert bezeichnet den negativen dekadischen Logarithmus der Aktivität der Hydronium-Ionen. Der pH-Wert wird erfindungsgemäß bei 20 °C unmittelbar in der Lösung mittels pH-sensitiver Elektroden nach Zwei-Punkt-Kalibrierung mit Pufferlösungen für die pH-Werte 4,01 und 7,01 potentiometrisch bestimmt.The pH denotes the negative decadic logarithm of the activity of the hydronium ions. According to the invention, the pH is determined potentiometrically at 20 ° C. directly in the solution by means of pH-sensitive electrodes after two-point calibration with buffer solutions for the pH values of 4.01 and 7.01.

Eine Verbindung ist wasserlöslich, wenn ihre Löslichkeit in entionisiertem Wasser (κ<1µScm-1) und bei einer Temperatur von 20 °C mindestens 1 g/kg beträgt. Alle Mengenangaben in "g/kg" beziehen sich auf den Anteil der jeweiligen Komponente pro Kilogramm der jeweils angezeigten Referenzlösung.A compound is water soluble if its solubility in deionized water (κ <1μScm -1 ) and at a temperature of 20 ° C is at least 1g / kg. All quantities in "g / kg" refer to the proportion of the respective component per kilogram of the respectively indicated reference solution.

Im erfindungsgemäßen Verfahren wird eine hervorragende Lackhaftung erzielt, die überraschenderweise auch in Abwesenheit von Phosphaten und bei hoher Toleranz gegenüber Aluminium-Ionen in der Beize auf die Kombination der im mehrstufigen Verfahren aufgebrachten Ti- und Zr-Auflage beruht. Die Abwesenheit von Phosphaten und hohe Toleranz gegenüber Aluminium-Ionen in der Beize ermöglichen, dass die Vorbehandlungsstufe im kontinuierlichen Betrieb keine Ausfällungen und damit keinen Schlamm produziert. Hierfür erforderlich ist die Anwesenheit der mehrbasigen α-Hydroxycarbonsäure.In the process according to the invention, an excellent paint adhesion is achieved which, surprisingly, also in the absence of phosphates and with high tolerance to aluminum ions in the stain, is based on the combination of the Ti and Zr coating applied in the multistage process. The absence of phosphates and high tolerance to aluminum ions in the stain enable the pretreatment stage to produce no precipitates and therefore no sludge in continuous operation. This requires the presence of the polybasic α-hydroxycarboxylic acid.

Mehrbasige α-Hydroxycarbonsäuren im Sinne der vorliegenden Erfindung besitzen mindestens zwei Carbonsäuregruppen und zumindest eine Hydroxyl-Gruppe in α-Stellung zu einer der Carbonsäuregruppen. In einer bevorzugten Ausführung ist die zumindest eine mehrbasige α-Hydroxycarbonsäure ausgewählt aus solchen Verbindungen, in denen jede Carboxyl-Gruppe eine Hydroxyl-Gruppe in α- oder β-Stellung aufweist, und die weiterhin bevorzugt nicht mehr als 8 Kohlenstoffatome aufweisen. Besonders bevorzugte Vertreter der mehrbasigen α-Hydroxycarbonsäure sind Weinsäure und/oder Zitronensäure, insbesondere bevorzugt Zitronensäure.Polybasic α-hydroxycarboxylic acids in the context of the present invention have at least two carboxylic acid groups and at least one hydroxyl group in α position to one of the carboxylic acid groups. In a preferred embodiment, the at least one polybasic α-hydroxycarboxylic acid is selected from those compounds in which each carboxyl group has a hydroxyl group in the α- or β-position, and which furthermore preferably has not more than 8 carbon atoms. Particularly preferred representatives of the polybasic α-hydroxycarboxylic acid are tartaric acid and / or citric acid, particularly preferably citric acid.

Für eine ausreichend hohe Toleranz gegenüber Aluminium-Ionen und weiterhin gute Ergebnisse in der Konditionierung der Aluminiumoberfläche für die Lackapplikation in der Vorbehandlungsstufe ist im erfindungsgemäßen Verfahren bevorzugt, dass der Anteil an mehrbasigen α-Hydroxycarbonsäuren in der Beizlösung mindestens 0,1 g/kg, besonders bevorzugt mindestens 0,5 g/kg, ganz besondersFor a sufficiently high tolerance to aluminum ions and furthermore good results in the conditioning of the aluminum surface for the paint application in the pretreatment stage is preferred in the inventive method that the proportion of polybasic α-hydroxycarboxylic acids in the pickling solution at least 0.1 g / kg, especially preferably at least 0.5 g / kg, especially

bevorzugt mindestens 1 g/kg beträgt. Aus Gründen der Wirtschaftlichkeit sind Anteile oberhalb von zehn Gramm pro Kilogramm der Beizlösung nicht sinnvoll und in der Beizlösung üblicherweise weder erforderlich für die Konditionierung der Aluminiumoberfläche in der Vorbehandlungsstufe noch für die Stabilisierung der gelösten Verbindungen des Elements Ti. Konsequenterweise ist der Anteil an mehrbasigen α-Hydroxycarbonsäuren in der Beizlösung daher in einem bevorzugten erfindungsgemäßen Verfahren nicht größer als 4 g/kg, besonders bevorzugt nicht größer als 2 g/kg.preferably at least 1 g / kg. For reasons of economy, proportions above ten grams per kilogram of the pickling solution are not meaningful and in the pickling solution usually neither necessary for the conditioning of the aluminum surface in the pretreatment stage nor for the stabilization of the dissolved compounds of the element Ti. Consequently, the proportion of polybasic α- Hydroxycarboxylic acids in the pickling solution therefore in a preferred process according to the invention not greater than 4 g / kg, more preferably not greater than 2 g / kg.

Der positive Effekt der in der Beize enthaltenden wasserlöslichen Verbindungen des Elements Titan in Gegenwart der Quelle für Fluorid-Ionen auf die nachrangige Konversionsbehandlung wird üblicherweise bereits mit geringen Mengen im Bereich von wenigen Milligramm an Ti pro Kilogramm der Beize erzielt. Bevorzugt liegt der Anteil an wasserlöslichen Verbindungen des Elements Ti in der Beizlösung bei mindestens 0,04 g/kg, besonders bevorzugt bei mindestens 0,1 g/kg. Oberhalb von einen Gramm an Ti pro Kilogramm der Beizlösung wird keine signifikante Verbesserung der Lackhaftung nach der Konversionsbehandlung erzielt. Auch zur Vermeidung von Ausfällungen und zur Erhöhung der Toleranz gegenüber Aluminium-Ionen ist es daher bevorzugt, wenn die Beizlösung vorzugsweise nicht mehr als 0,6 g/kg, besonders bevorzugt nicht mehr als 0,3 g/kg jeweils bezogen auf das Element Ti an wasserlöslichen Verbindungen des Elements Ti enthält.The positive effect of the mordant-containing water-soluble compounds of the element titanium in the presence of the source of fluoride ions on the subordinate conversion treatment is usually already achieved with small amounts in the range of a few milligrams of Ti per kilogram of mordant. The proportion of water-soluble compounds of the element Ti in the pickling solution is preferably at least 0.04 g / kg, more preferably at least 0.1 g / kg. Above one gram of Ti per kilogram of pickling solution, no significant improvement in paint adhesion is obtained after the conversion treatment. Also, to avoid precipitation and to increase the tolerance to aluminum ions, it is therefore preferable if the pickling solution is preferably not more than 0.6 g / kg, more preferably not more than 0.3 g / kg in each case based on the element Ti of water-soluble compounds of the element Ti.

Als wasserlösliche Verbindungen des Elements Ti sind Titanylsulfat (TiO(SO4)), Titanylnitrat (TiO(NO3)2)und/oder Hexafluorotitansäure (H2TiF6) sowie ihre Salze gut geeignet und daher in der Beizlösung des erfindungsgemäßen Verfahrens bevorzugte Vertreter, insbesondere bevorzugt ist Hexafluorotitansäure und ihre Salze.As water-soluble compounds of the element Ti titanyl sulfate (TiO (SO 4 )), titanyl nitrate (TiO (NO 3 ) 2 ) and / or hexafluorotitanic (H 2 TiF 6 ) and their salts are well suited and therefore preferred in the pickling solution of the process according to the invention , particularly preferred is hexafluorotitanic acid and its salts.

Eine Quelle für Fluorid-Ionen ist erfindungsgemäß erforderlich für eine hinreichende Beize des aus Aluminium gefertigten Bauteils ohne die eine reproduzierbare weitestgehend oxidfreie Oberfläche nicht eingestellt werden kann und der positive Effekt der in der Beize enthaltenden wasserlöslichen Verbindungen des Elements Titan auf die Lackhaftung nicht zum Tragen kommen kann.A source of fluoride ions according to the invention is required for a sufficient stain of the aluminum-made component without a reproducible largely oxide-free surface can not be adjusted and the positive effect of containing in the stain water-soluble compounds of the element titanium on the paint adhesion does not apply can.

Eine Quelle für Fluorid-Ionen im Sinne der vorliegenden Erfindung ist jede wasserlösliche anorganische Verbindung enthaltend Fluor, die als 0,1 Gew.-%ige wässrige Lösung nach TISAB-Pufferung mit einer aliquoten Menge des Puffers mindestens 100 mg/kg Fluorid-Ionen, potentiometrisch bei 20 °C mittels einer Fluorid-Ionensensitiven Elektrode nach der DIN 38 405-D-4-1 bestimmt, freisetzt. Eine aliquote Menge des Puffers resultiert in einem volumenbezogenen Mischungsverhältnis von Puffer zur wässrigen Lösung enthaltend die Quelle an Fluorid von 1:1. Der TISAB Puffer ("Total lonic Strength Adjustment Buffer") wird hergestellt durch Auflösung von 58 g NaCl, 1 g Natriumcitrat und 50 ml Eisessig in 500 ml entionisiertem Wasser (κ < 1µScm-1) und Einstellen eines pH-Wertes von 5,3 mittels 5 N NaOH sowie Auffüllen auf ein Gesamtvolumen von 1000 ml wiederum mit entionisiertem Wasser (κ < 1µScm-1).A source of fluoride ions in the context of the present invention is any water-soluble inorganic compound containing fluorine containing at least 100 mg / kg of fluoride ions as 0.1% by weight aqueous solution after TISAB buffering with an aliquot of the buffer. determined potentiometrically at 20 ° C by means of a fluoride ion-sensitive electrode according to DIN 38 405-D-4-1, released. An aliquot of the buffer results in a volume mixing ratio of buffer to aqueous solution containing the source of fluoride of 1: 1. The TISAB Buffer (Total Lonic Strength Adjustment Buffer) is manufactured with a resolution of 58 g NaCl, 1 g of sodium citrate and 50 ml of glacial acetic acid in 500 ml of deionized water (κ <1 μScm -1 ) and setting a pH of 5.3 by means of 5 N NaOH and filling to a total volume of 1000 ml again with deionized water (κ < 1μScm -1 ).

Vorliegend ist es bevorzugt, wenn der Gesamtfluorid-Gehalt in der Beizlösung mindestens 0,02 g/kg, besonders bevorzugt mindestens 0,05 g/kg, ganz besonders bevorzugt mindestens bei 0,1 g/kg berechnet als F beträgt. Der Gesamtfluorid-Gehalt wird im Rahmen der vorliegenden Erfindung mittels einer Fluorid-Ionensensitiven Elektrode nach der DIN 38 405-D-4-1 wie zuvor beschrieben bestimmt.In the present case, it is preferred if the total fluoride content in the pickling solution is at least 0.02 g / kg, particularly preferably at least 0.05 g / kg, very particularly preferably at least 0.1 g / kg calculated as F. The total fluoride content is determined in the context of the present invention by means of a fluoride ion-sensitive electrode according to DIN 38 405-D-4-1 as described above.

Der Anteil an freiem Fluorid ist in der Beizlösung ist für eine moderate Beizrate des Aluminiumwerkstoffes gering zu halten. In einer bevorzugten Ausführungsform ist der Anteil an freiem Fluorid daher kleiner als 10 mg/kg, besonders bevorzugt kleiner als 5 mg/kg jeweils potentiostatisch unmittelbar in der Beizlösung bei 20 °C mittels kalibrierter Fluorid-sensitiver Elektrode bestimmt.The proportion of free fluoride in the pickling solution is to be kept low for a moderate pickling rate of the aluminum material. In a preferred embodiment, the proportion of free fluoride is therefore less than 10 mg / kg, more preferably less than 5 mg / kg each potentiostatically determined directly in the pickling solution at 20 ° C by means of calibrated fluoride-sensitive electrode.

Geeignete Quellen für Fluorid-Ionen sind beispielsweise Ammoniumbifluord, Natriumfluorid und/oder komplexe Fluoride, insbesondere Hexafluorotitansäure und ihre Salze. Jedoch sollten vorzugsweise keine komplexen Fluoride des Elements Zr in der Beizlösung enthalten sein, da diese ebenfalls geeignet sind eine Belegung der Oberflächen des aus Aluminium gefertigten Bauteils herbeizuführen und daher mit der durch die wasserlöslichen Verbindungen des Elements Ti erzielten Konditionierung der Aluminiumoberflächen konkurrieren.Suitable sources of fluoride ions are, for example, ammonium bifluoride, sodium fluoride and / or complex fluorides, in particular hexafluorotitanic acid and its salts. However, preferably, complex fluorides of the element Zr should not be included in the pickling solution since these are also likely to cause the surfaces of the aluminum-made component to adhere and therefore compete with the conditioning of the aluminum surfaces achieved by the water-soluble compounds of the element Ti.

In einer bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens enthält die Beizlösung daher insgesamt weniger als 0,02 g/kg, besonders bevorzugt weniger als 0,01 g/kg, ganz besonders bevorzugt weniger als 0,004 g/kg an wasserlöslichen Verbindungen des Elements Zr berechnet als Zr.In a preferred embodiment of the method according to the invention, the pickling solution therefore contains a total of less than 0.02 g / kg, more preferably less than 0.01 g / kg, most preferably less than 0.004 g / kg of water-soluble compounds of the element Zr calculated as Zr ,

Die Beizlösung weist in einem erfindungsgemäßen Verfahren vorzugsweise einen pH-Wert unterhalb von 2,0 auf. Damit ist regelmäßig sichergestellt, dass eine hinreichende Beize in der Vorbehandlungsstufe erfolgen kann.The pickling solution preferably has a pH below 2.0 in a process according to the invention. This ensures on a regular basis that a sufficient stain can take place in the pretreatment stage.

In einer bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens weist die Beizlösung einen freien Säuregehalt von zumindest 6 Punkten auf, so dass ein von der Art des zu behandelnden Aluminiummaterials weitestgehend unabhängiger und für die nachfolgende Konversionsbehandlung hinreichender Beizabtrag sichergestellt ist, beispielsweise in der Serienbehandlung von jeweils aus unterschiedlichen Aluminiummaterialien gefertigten Einzelbauteilen oder in der Serienbehandlung von aus einem Mix unterschiedlicher Aluminiummaterialien gefertigter Einzelbauteile. Umgekehrt sollte der freie Säuregehalt in Punkten vorzugsweise nicht größer als 10 sein, um eine ausreichende Konditionierung der Aluminiumoberflächen auf der Basis der in der Beizlösung enthaltenden wasserlöslichen Verbindungen des Elements Ti zu bewirken.In a preferred embodiment of the process according to the invention, the pickling solution has a free acid content of at least 6 points, so that a pickling removal which is largely independent of the type of aluminum material to be treated and sufficiently adequate for the subsequent conversion treatment is ensured, for example in the series treatment of different aluminum materials manufactured individual components or in the series treatment of individual components produced from a mix of different aluminum materials. Conversely, the free acid content in points should preferably not be greater than 10 in order to effect sufficient conditioning of the aluminum surfaces on the basis of the water-soluble compounds of Ti element contained in the pickling solution.

Der freie Säuregehalt in Punkten wird im Rahmen der vorliegenden Erfindung bestimmt, indem man 10 ml der Beizlösung auf 50 ml verdünnt und mit 0,1 N Natronlauge bis zu einem pH-Wert von 3,6 titriert. Der Verbrauch an Millilitern Natronlauge gibt die Punktzahl an.The free acid content in points is determined in the context of the present invention by diluting 10 ml of the pickling solution to 50 ml and titrating with 0.1 N sodium hydroxide solution to a pH of 3.6. The consumption of milliliters of caustic soda indicates the score.

Neben der Einstellung eines freien Säuregehalts in der Beizlösung als Regelungsparameter für die Bereitstellung von im erfindungsgemäßen Verfahren optimal gebeizten Oberflächen der aus Aluminium gefertigten Bauteile, hat sich das Vorliegen einer gewissen Pufferkapazität oder eines gewissen Säurevorrats für eine stabile Prozessführung bei einer Serienbehandlung herausgestellt. Hierfür ist der Gesamtsäuregehalt von Bedeutung und dieser liegt in der Beizlösung des erfindungsgemäßen Verfahrens vorzugsweise bei zumindest 12 Punkten, jedoch vorzugsweise bei nicht mehr als 18 Punkten. Der Gesamtsäuregehalt wird erfindungsgemäß analog zur freien Säure bestimmt mit dem Unterschied, dass bis zu einem pH-Wert von 8,5 titriert wird.In addition to the setting of a free acid content in the pickling solution as a control parameter for the provision of optimally pickled in the process according to the invention surfaces of aluminum-made components, the presence of a certain buffer capacity or a certain acidity has proven to be a stable process control in a series treatment. For this purpose, the total acid content of importance and this is in the pickling solution of the method according to the invention preferably at least 12 points, but preferably not more than 18 points. The total acid content is inventively determined analogously to the free acid with the difference that is titrated to a pH of 8.5.

Bezüglich der in der Beizlösung der Vorbehandlungsstufe des erfindungsgemäßen Verfahrens für die Einstellung des Säuregehaltes zu verwendenden Säure wurde festgestellt, dass diese schwefelsauer für eine gute Beizwirkung sein sollte. Eine wässrige Beizlösung ist schwefelsauer, wenn sie zur Einstellung des pH-Wertes Schwefelsäure enthält und der Anteil an anderen Säuren mit einem pKS1-Wert von weniger als 2,5 für den ersten Deprotonierungsschritt geringer als 1 g/kg, besonders bevorzugt geringer als 0,5 g/kg, insbesondere bevorzugt geringer als 0,1 g/kg ist.With regard to the acid to be used in the pickling solution of the pretreatment stage of the process according to the invention for the adjustment of the acid content, it was determined that this should be sulfur-acidic for a good pickling action. An aqueous pickling solution is sulfuric if it contains sulfuric acid to adjust the pH and the proportion of other acids with a pKS 1 value of less than 2.5 for the first deprotonation step is less than 1 g / kg, more preferably less than 0 5 g / kg, more preferably less than 0.1 g / kg.

Weiterhin ist die Beizlösung im erfindungsgemäßen Verfahren zur Vermeidung der Ausfällung schwerlöslicher Salze und der Schichtbildung auf den Oberflächen des aus Aluminium gefertigten Bauteils phosphatfrei. Eine wässrige Beizlösung ist phosphatfrei, wenn sie weniger als 0,5 g/kg, vorzugsweise weniger als 0,1 g/kg, besonders bevorzugt weniger als 0,05 g/kg an in Wasser gelösten Phosphaten berechnet als PO4 enthält.Furthermore, the pickling solution in the process according to the invention for preventing the precipitation of sparingly soluble salts and the film formation on the surfaces of the aluminum-made component is phosphate-free. An aqueous pickling solution is phosphate-free if it contains less than 0.5 g / kg, preferably less than 0.1 g / kg, more preferably less than 0.05 g / kg of phosphates dissolved in water, calculated as PO 4 .

In einem bevorzugten erfindungsgemäßen Verfahren enthält die Beizlösung zusätzlich eine oberflächenaktive organische Verbindung, besonders bevorzugt ein Niotensid, wobei der Anteil an oberflächenaktiven organischen Substanzen in der Beizlösung vorzugsweise zumindest 0,1 mmol/L beträgt. In diesem Zusammenhang sind allgemein solche Niotenside bevorzugt, deren HLB-Wert (Hydrophilic-Lipophilic-Balance) zumindest 8, besonders bevorzugt zumindest 10, insbesondere bevorzugt zumindest 12 ist, jedoch besonders bevorzugt nicht mehr als 18, insbesondere bevorzugt nicht mehr als 16 beträgt. Der HLB-Wert dient zur quantitativen Klassifizierung von Niotensiden entsprechend ihrer inneren molekularen Struktur, wobei eine Aufgliederung des Niotensids in eine lipophile und eine hydrophile Gruppe vorgenommen wird. Der HLB Wert kann auf der willkürlichen Skala Werte von Null bis 20 annehmen und berechnet sich gemäß vorliegender Erfindung wie folgt: HLB = 20 · 1 M L / M

Figure imgb0001
mit

ML:
Molmasse der lypophilen Gruppe des Niotensids
M:
Molmasse des Niotensids
In a preferred process according to the invention, the pickling solution additionally contains a surface-active organic compound, more preferably a nonionic surfactant, wherein the proportion of surface-active organic substances in the pickling solution is preferably at least 0.1 mmol / L. In this context, preference is generally given to those nonionic surfactants whose HLB value (hydrophilic-lipophilic balance) is at least 8, more preferably at least 10, particularly preferably at least 12, but is particularly preferably not more than 18, particularly preferably not more than 16. The HLB value is used for the quantitative classification of nonionic surfactants according to their internal molecular structure, with a breakdown of the nonionic surfactant into a lipophilic and a hydrophilic group. The HLB value may take on the arbitrary scale values of zero to 20 and is calculated according to the present invention as follows: HLB = 20 · 1 - M L / M
Figure imgb0001
With
M L :
Molar mass of the hypophilic group of nonionic surfactant
M:
Molar mass of the nonionic surfactant

Insbesonders geeignete Niotenside sind ausgewählt aus alkoxylierten Alkylalkoholen, alkoxylierten Fettaminen und/oder Alkylpolyglycosiden, besonders bevorzugt aus alkoxylierten Alkylalkoholen und/oder alkoxylierten Fettaminen, insbesondere bevorzugt aus alkoxylierten Alkylalkoholen. DieParticularly suitable nonionic surfactants are selected from alkoxylated alkyl alcohols, alkoxylated fatty amines and / or alkylpolyglycosides, particularly preferably from alkoxylated alkyl alcohols and / or alkoxylated fatty amines, particularly preferably from alkoxylated alkyl alcohols. The

alkoxylierten Alkylalkohole und/oder alkoxylierten Fettamine sind dabei vorzugsweise endgruppenverschlossen, besonders bevorzugt mit einer Alkyl-Gruppe, die wiederum vorzugsweise nicht mehr als 8 Kohlenstoffatome, besonders bevorzugt nicht mehr als 4 Kohlenstoffatome aufweist.Alkoxylated alkyl alcohols and / or alkoxylated fatty amines are preferably end-capped, more preferably having an alkyl group, which in turn preferably has not more than 8 carbon atoms, more preferably not more than 4 carbon atoms.

Im erfindungsgemäßen Verfahren ist es von Vorteil für eine ausreichende Beize und Konditionierung der Aluminiumoberflächen und daher auch bevorzugt, dass das Bauteil für eine solche Dauer mit der Beizlösung in Kontakt gebracht wird, die ausreicht, um mindestens 2 mg Aluminium pro Quadratmeter der in Kontakt gebrachten Oberfläche des Bauteils zu beizen und besonders bevorzugt ebenso ausreicht um eine Schichtauflage von mindestens 4 mg Titan pro Quadratmeter auf der in Kontakt gebrachten Oberfläche des Bauteils zu erzeugen. In diesem Zusammenhang ist die Beizlösung auch für die Einhaltung vorbehandlungstypischer Behandlungszeiten vorzugsweise derart eingestellt, dass für eine für eine Legierung nach EN AW-6014 (AIMg0.6Si0.6V) bei 40 °C in einer ungerührten Beizlösung des erfindungsgemäßen Verfahrens eine Beizrate von zumindest 15 mgm-2s-1 bezogen auf das Element Aluminium resultiert.In the process of the invention, it is advantageous for sufficient staining and conditioning of the aluminum surfaces, and therefore also preferred, for the component to be contacted with the pickling solution for a duration sufficient to contain at least 2 mg of aluminum per square meter of surface area contacted to pickle the component and particularly preferably also sufficient to produce a coating layer of at least 4 mg of titanium per square meter on the contacted surface of the component. In this context, the pickling solution is also preferably adjusted for the observance of pretreatment-typical treatment times such that for a alloy according to EN AW-6014 (AIMg0.6Si0.6V) at 40 ° C in an unstirred pickling solution of the method according to the invention, a pickling rate of at least 15 mgm -2 s -1 based on the element aluminum results.

In der der Beize unmittelbar nachfolgenden Konversionsbehandlung wird im erfindungsgemäßen Verfahren eine Konversionsschicht auf Basis der Elemente Zr und/oder Ti aufgebracht. Für eine hinreichende Lackhaftung ist bevorzugt, wenn nach der Konversionsbehandlung eine Schichtauflage von zumindest 50 µmol/m2, vorzugsweise zumindest 100 µmol/m2, besonders bevorzugt zumindest 200 µmol/m2, jedoch vorzugsweise von nicht mehr als 500 µmol/m2 bestimmt mittels Röntgenfluoreszenzanalyse (RFA) bezogen auf die Summe der Elemente Zr und Ti resultiert, und die aus Aluminium gefertigten Bauteile daher für eine solche Dauer mit der Konversionsbehandlungslösung in Kontakt gebracht werden, dass eine entsprechende Schichtauflage realisiert ist. Hierfür ist weiterhin bevorzugt, dass in der Konversionsbehandlungslösung des erfindungsgemäßen Verfahrens mindestens 0,1 mmol/kg, besonders bevorzugt mindestens 0,5 mmol/kg an wasserlöslichen Verbindungen der Elemente Zr und/oder Ti berechnet als entsprechende Menge der Elemente Zr und/oder Ti enthalten sind, jedoch aus wirtschaftlichen Gründen vorzugsweise nicht mehr als 5 mmol/kg, besonders bevorzugt nicht mehr als 3 mmol/kg. Geeignete Vertreter wasserlöslicher Verbindungen sind Ammoniumzirconiumcarbonat ((NH4)2Zr(OH)2(CO3)2), Titanylsulfat (TiO(SO4)), Zirconiumsulfat (Zr(SO4)2), Titannitrat (Ti(NO3)4), Zirconiumnitrat (Zr(NO3)4), Zirconylnitrat (ZrO(NO3)2), Titanylnitrat (TiO(NO3)2), Ammoniumzirconiumlactat (NH4Zr(C3H5O3)5), Zirconiumperchlorat (Zr(ClO4)4), Titanperchlorat (Ti(ClO4)4), und/oder Hexafluorotitansäure (H2TiF6) bzw. Hexafluorozirkonsäure (H2ZrF6) sowie ihre jeweiligen Salze.In the treatment immediately following the pickle, a conversion layer based on the elements Zr and / or Ti is applied in the method according to the invention. For a sufficient paint adhesion is preferred if after the conversion treatment, a layer of at least 50 .mu.mol / m 2 , preferably at least 100 .mu.mol / m 2 , more preferably at least 200 .mu.mol / m 2 , but preferably determined by not more than 500 .mu.mol / m 2 by X-ray fluorescence analysis (RFA) based on the sum of the elements Zr and Ti, and the components made of aluminum are therefore brought into contact with the conversion treatment solution for such a duration that a corresponding layer support is realized. For this purpose, it is further preferred that in the conversion treatment solution of the process according to the invention at least 0.1 mmol / kg, more preferably at least 0.5 mmol / kg of water-soluble compounds of the elements Zr and / or Ti calculated as a corresponding amount of the elements Zr and / or Ti however, for economic reasons, preferably not more than 5 mmol / kg, more preferably not more than 3 mmol / kg. Suitable representatives of water-soluble compounds are ammonium zirconium carbonate ((NH 4 ) 2 Zr (OH) 2 (CO 3 ) 2 ), titanyl sulfate (TiO (SO 4 )), zirconium sulfate (Zr (SO 4 ) 2 ), titanium nitrate (Ti (NO 3 ) 4 Zirconium nitrate (Zr (NO 3 ) 4 ), zirconyl nitrate (ZrO (NO 3 ) 2 ), titanyl nitrate (TiO (NO 3 ) 2 ), ammonium zirconium lactate (NH 4 Zr (C 3 H 5 O 3 ) 5 ), zirconium perchlorate ( Zr (ClO 4 ) 4 ), titanium perchlorate (Ti (ClO 4 ) 4 ), and / or hexafluorotitanic acid (H 2 TiF 6 ) or hexafluorozirconic acid (H 2 ZrF 6 ) and their respective salts.

In diesem Zusammenhang ist für eine effektive Schichtbildung auf Basis der Elemente Zr und/oder Ti in der Konversionsbehandlung weiterhin bevorzugt, wenn das molare Verhältnis des Gesamtanteils wasserlöslicher Verbindungen der Elemente Zr und Ti bezogen auf die jeweiligen Elemente zum Gesamtfluorid-Gehalt in der Konversionsbehandlungslösung mindestens 0,1, besonders bevorzugt mindestens 0,4 beträgt. Es hat sich überraschenderweise herausgestellt, dass die VerwendungIn this connection, for effective film formation based on the elements Zr and / or Ti in the conversion treatment, it is further preferable that the molar ratio of the total content of water-soluble compounds of the elements Zr and Ti relative to the respective elements to the total fluoride content in the conversion treatment solution is at least zero , 1, more preferably at least 0.4. It has surprisingly been found that the use

wasserlöslicher Verbindungen des Elements Zr, insbesondere von Hexafluorozirkonsäure und ihren Salzen, in der Konversionsbehandlungslösung in Kombination mit der Ti-haltigen Beizlösung die besten Lackhaftungsergebnisse erzielt und daher im erfindungsgemäßen Verfahren bevorzugt ist.water-soluble compounds of the element Zr, in particular of hexafluorozirconium acid and their salts, achieved in the conversion treatment solution in combination with the Ti-containing pickling solution, the best paint adhesion results and is therefore preferred in the process according to the invention.

In einer bevorzugten Ausgestaltung des erfindungsgemäßen Verfahrens liegt der pH-Wert der Konversionsbehandlungslösung in der Vorbehandlungsstufe bei zumindest 1,8, besonders bevorzugt bei zumindest 2,0.In a preferred embodiment of the method according to the invention, the pH of the conversion treatment solution in the pretreatment stage is at least 1.8, more preferably at least 2.0.

Für eine hinreichende Konversionsbehandlung in der Vorbehandlungsstufe des erfindungsgemäßen Verfahrens bedarf es nicht der Anwesenheit von wasserlöslichen Verbindungen des Elements Chrom. In einer weiteren bevorzugten Ausgestaltung des erfindungsgemäßen Verfahrens enthält die Konversionsbehandlungslösung daher insgesamt weniger als 0,1 g/kg an wasserlöslichen Verbindungen des Elements Chroms berechnet als Cr. Auch ist der Zusatz von Phosphat-Ionen zur Konversionsbehandlungslösung nicht vorteilhaft, so dass selbige im erfindungsgemäßen Verfahren analog zur Beizlösung phosphatfrei ist und daher weniger als 0,5 g/kg, vorzugsweise weniger als 0,1 g/kg, besonders bevorzugt weniger als 0,05 g/kg an in Wasser gelösten Phosphaten berechnet als PO4 enthält.For a sufficient conversion treatment in the pretreatment stage of the process according to the invention, it is not necessary for the presence of water-soluble compounds of the element chromium. In a further preferred embodiment of the method according to the invention, the conversion treatment solution therefore contains a total of less than 0.1 g / kg of water-soluble compounds of the element chromium calculated as Cr. Also, the addition of phosphate ions to the conversion treatment solution is not advantageous, so that selbige in the process according to the invention is analogous to the pickling solution phosphate-free and therefore less than 0.5 g / kg, preferably less than 0.1 g / kg, more preferably less than 0 , 05 g / kg of phosphates dissolved in water, calculated as PO 4 .

Aus Aluminium gefertigte Bauteile, die gemäß der vorliegenden Erfindung korrosionsschützend behandelt werden, sind solche, deren metallischer Bestandteil aus Aluminium und/oder Aluminiumlegierungen, insbesondere Aluminiumgusslegierungen, bestehen oder zusammengesetzt ist. Eine Legierung ist eine Aluminiumlegierung, insofern sie zu mindestens 50 At.-% aus dem Element AI besteht. Im erfindungsgemäßen Verfahren geeignete aus Aluminium gefertigte Bauteile sind beispielsweise ausgewählt aus Halbzeugen wie Blech, Band, Coil oder Draht oder aus komplexen dreidimensionalen Fertigungsobjekten wie Felgen für den automobilen Bereich. Die Bauteile wiederum können aus Bandmaterial oder Blechen geformt und/oder zusammengefügt oder im Gussverfahren hergestellt worden sein. Im Rahmen der vorliegenden Erfindung bevorzugt ist die Behandlung von aus Aluminiumgusslegierungen, beispielsweise AA 6014, gefertigten Bauteilen, insbesondere Felgen für den automobilen Bereich.Components made of aluminum, which are treated in accordance with the present invention corrosion protection, are those whose metallic component consists of aluminum and / or aluminum alloys, in particular aluminum casting alloys, or is composed. An alloy is an aluminum alloy in that it consists of at least 50 at.% Of the element Al. Suitable components made of aluminum in the method according to the invention are for example selected from semi-finished products such as sheet metal, strip, coil or wire or from complex three-dimensional production objects such as rims for the automotive sector. In turn, the components may be formed from strip material or sheets and / or joined together or made by casting. In the context of the present invention, the treatment of components made of cast aluminum alloys, for example AA 6014, in particular rims for the automotive sector is preferred.

Eine Vorbehandlungsstufe im Sinne der vorliegenden Erfindung ist eine von der Aufbringung der Lackierung getrennte Verfahrensstufe umfassend die voneinander zeitlich getrennten Verfahrensschritte Beize und Konversionsbehandlung unter Zuhilfenahme von jeweils unabhängig voneinander in Systemtanks bevorrateten flüssigen Zusammensetzungen in Form der Beiz- bzw. der Konversionsbehandlungslösung. In einer bevorzugten Ausführungsform werden die aus Aluminium gefertigten Bauteile in der Vorbehandlungsstufe des erfindungsgemäßen Verfahrens in Serie vorbehandelt. Als Vorbehandlung in Serie gilt erfindungsgemäß das In-Kontakt-Bringen einer Vielzahl von aus Aluminium gefertigten Bauteilen mit der jeweils in einem Systemtank bevorrateten Beiz- und Konversionsbehandlungslösung, ohne dass nach jeder Vorbehandlung eines einzelnen aus Aluminium gefertigten Bauteils ein vollständiger Austausch mit Neuansatz der in den Systemtanks der Vorbehandlungsstufe bevorrateten Beiz- und Konversionsbehandlungslösungen erfolgt.A pretreatment step in the sense of the present invention is a process step which is separate from the application of the paint finish and which comprises the process steps of pickling and conversion treatment which are separated from one another with the aid of liquid compositions in the form of the pickling liquor and each independently stored in system tanks Conversion treatment solution. In a preferred embodiment, the components made of aluminum are pretreated in series in the pretreatment stage of the process according to the invention. According to the invention, pretreatment in series involves contacting a plurality of components made of aluminum with the pickling and conversion treatment solution respectively stored in a system tank, without a complete exchange with a new batch of the following in each of the pretreatment of a single component made of aluminum System tanks of pre-treatment stage stockpiled pickling and conversion treatment solutions takes place.

Der Übergang des Bauteils von der Beize in die Konversionsbehandlung erfolgt "unmittelbar". Erfindungsgemäß bedeutet dies, dass die Konversionsbehandlung der Beize nachfolgt, ohne dass eine Benetzung des Bauteils mit einer anderen flüssigen Zusammensetzung, die weder eine Spülnoch Konversionsbehandlungslösung im Sinne der vorliegenden Erfindung darstellt, zwischengeschaltet ist, vorzugsweise ist jedoch mindestens ein Spülschritt auf Basis einer oder mehrerer Spüllösungen zwischengeschaltet. Ein "Spülschritt" im Sinne der vorliegenden Erfindung bezeichnet einen Vorgang, der allein dazu bestimmt ist, Aktivkomponenten aus einem unmittelbar vorausgegangenem nasschemischen Behandlungsschritt, die in einem dem Bauteil anhaftenden Nassfilm gelöst vorliegen, mittels einer Spüllösung von der Oberfläche des Bauteils möglichst weitgehend zu entfernen, ohne dass die zu entfernenden Aktivkomponenten durch andere ersetzt werden. Aktivkomponenten sind dabei in Wasser gelöste Verbindungen, die sich bereits durch das bloße In-Kontakt-Bringen der metallischen Oberflächen des Bauteils mit der Spülflüssigkeit verbrauchen. So kann die Spülflüssigkeit beispielsweise Stadtwasser sein.The transition of the component from the stain into the conversion treatment takes place "directly". According to the invention, this means that the conversion treatment follows the pickling without intervening a wetting of the component with another liquid composition which is neither a flushing nor conversion treatment solution in the sense of the present invention, but preferably at least one flushing step is based on one or more flushing solutions interposed. A "rinsing step" in the sense of the present invention denotes a process which is intended solely to remove as far as possible active components from an immediately preceding wet-chemical treatment step, which are dissolved in a wet film adhering to the component, by means of a rinsing solution from the surface of the component. without replacing the active components to be removed by others. Active components are dissolved in water compounds that consume already by the mere contacting of the metallic surfaces of the component with the rinsing liquid. For example, the rinsing fluid can be city water.

Zudem findet in einem bevorzugten erfindungsgemäßen Verfahren in der Vorbehandlungsstufe zwischen Beize und Konversionsbehandlung kein solcher Verfahrensschritt statt, bei dem durch die Bereitstellung und Nutzung technischer Mittel eine Trocknung oder eine Entfernung des wässrigen, auf der Oberfläche des Bauteils anhaftenden Flüssigfilms beabsichtigt ist, insbesondere durch Zuführung thermischer Energie oder Aufprägen einer Luftströmung.Moreover, in a preferred process according to the invention in the pretreatment stage between pickling and conversion treatment, no such process step takes place in which drying and removal of the aqueous liquid film adhering to the surface of the component is intended by the provision and use of technical means, in particular by supplying thermal Energy or imprinting an airflow.

Die im erfindungsgemäßem Verfahren zu behandelnden Bauteile stammen aus einem vorgelagerten Fertigungsprozess deren Oberflächen daher zur Gewährleistung einer guten Beize zunächst von Verunreinigungen wie Formtrennhilfsmitteln befreit werden sollten. In einem bevorzugten erfindungsgemäßen Verfahren wird das Bauteil daher in der Vorbehandlungsstufe vor dem In-Kontakt-Bringen mit der Beizlösung einer alkalischen Entfettung zugeführt, besonders bevorzugt durch In-Kontakt-Bringen mit einer alkalischen wässrigen Zusammensetzung, die einen pH-Wert oberhalb von 9, jedoch vorzugsweise unterhalb von 12, und eine freie Alkalität von mindestens 3 Punkten, jedoch vorzugsweise weniger als 6 Punkten aufweist und optional oberflächenaktive Verbindungen, vorzugsweise ausgewählt aus nichtionischen Tensiden, enthält.The components to be treated in the process according to the invention originate from an upstream production process whose surfaces should therefore first be freed from impurities, such as mold release aids, in order to ensure good pickling. In a preferred method according to the invention, the component is therefore supplied in the pretreatment stage before being brought into contact with the pickling solution to an alkaline degreasing, more preferably by contacting with an alkaline aqueous composition having a pH above 9, however, preferably below 12, and having a free alkalinity of at least 3 points, but preferably less than 6 points, and optionally containing surface active compounds, preferably selected from nonionic surfactants.

In diesem Zusammenhang ist weiterhin bevorzugt, dass nach der alkalischen Entfettung und vor dem In-Kontakt-Bringen mit der Beizlösung ein Spülschritt, jedoch vorzugsweise kein Trocknungsschritt erfolgt.In this context, it is further preferred that after the alkaline degreasing and before bringing into contact with the pickling solution, a rinsing step, but preferably no drying step takes place.

Die Applikation der in den jeweiligen Systemtanks der Vorbehandlungsstufe bevorrateten Reinigungs-, Beiz- und Konversionsbehandlungslösung kann mit allen im Stand der Technik bekannten Verfahren erfolgen, wobei Tauch- und Sprühverfahren für das In-Kontakt-Bringen der aus Aluminium gefertigtenThe application of the cleaning, pickling and conversion treatment solution stored in the respective system tanks of the pre-treatment stage can be carried out by all methods known in the art, with immersion and spraying methods for bringing the aluminum made into contact

Bauteile mit diesen Lösungen bevorzugt sind, besonders bevorzugt ist das Sprühverfahren als Applikationsart.Components with these solutions are preferred, the spray method is particularly preferred as the type of application.

Die der Vorbehandlungsstufe nachfolgende Lackierung beinhaltet erfindungsgemäß die Aufbringung einer Zusammensetzung enthaltend ein chemisch oder physikalisch aushärtendes Bindemittel zur Ausbildung einer Deckschicht auf dem vorbehandeltem und aus Aluminium gefertigtem Bauteil, wobei die aus der Lackierung resultierende Deckschicht im getrockneten oder ausgehärteten Zustand eine Schichtdicke von vorzugsweise zumindest einem Mikrometer, besonders bevorzugt von zumindest 10 µm, gemessen gemäß Keilschnittverfahren nach der DIN 50986:1979-03 aufweist.According to the invention, the coating following the pretreatment stage comprises the application of a composition comprising a chemically or physically hardening binder to form a cover layer on the pretreated and aluminum-made component, wherein the cover layer resulting from the coating in the dried or cured state has a layer thickness of preferably at least one micrometer , particularly preferably of at least 10 .mu.m, measured according to the wedge-cut method according to DIN 50986: 1979-03.

Geeignete Lacke sind autophorethische Lacke, Elektrotauchlacke, Pulverlacke sowie mit konventionellen Mitteln applizierbare Flüssiglacke. Hinsichtlich der verwendeten Bindemittel können erfindungsgemäß sowohl Lacke, die auf anorganischen Bindemitteln wie beispielsweise Silkat oder Kalk basieren, als auch Lacke basierend auf organischen Bindemittel eingesetzt werden. Besonders vorteilhaft ist erfindungsgemäß die nachfolgende Auftragung von auf organischen Bindemitteln basierten Lacken, insbesondere solchen, die weniger als 10 Gew.-% an organischen Lösemittelbestandteilen enthalten, die einem Siedepunkt unterhalb von 150 °C bei 1 bar aufweisen. In diesem Zusammenhang sind daher Pulverlacke bevorzugt, insbesondere solche mit Bindemitteln auf Basis von Epoxidharzen, carboxy- und hydroxygruppenhaltige Polyesterharzen und/oder Acrylatharzen, die jeweils eine hervorragende Lackhaftung auf den entsprechend der Erfindung vorbehandelten aus Aluminium gefertigten Bauteilen aufweisen.Suitable lacquers are autophoretic lacquers, electrodeposition lacquers, powder lacquers and liquid lacquers which can be applied by conventional means. With regard to the binders used, both paints based on inorganic binders, such as, for example, silicate or lime, and paints based on organic binders can be used according to the invention. According to the invention, the following application of lacquers based on organic binders, in particular those containing less than 10% by weight of organic solvent constituents, which have a boiling point below 150 ° C. at 1 bar, is particularly advantageous. In this context, therefore, powder coatings are preferred, in particular those with binders based on epoxy resins, carboxyl- and hydroxyl-containing polyester resins and / or acrylate resins, each having an excellent paint adhesion to the pretreated according to the invention made of aluminum components.

Das aus Aluminium gefertigte Bauteil kann nach der Vorbehandlung und vor der Lackierung einer Spüle unterworfen werden, die dazu dient, einen auf der Oberfläche anhaftenden Nassfilm der Konversionslösung zu entfernen bevor der Lack aufgetragen wird. Ferner ist es üblich und kann daher bevorzugt sein, dass das Bauteil vor der Auftragung des Lackes getrocknet wird. Dies ist insbesondere dann der Fall, wenn ein Pulverlack aufzutragen ist, für die im erfindungsgemäßen Verfahren ein besonders guter Lackhaftgrund bereitgestellt wird und daher eine Präferenz besteht.The component made of aluminum can be subjected after the pretreatment and before the painting of a sink, which serves to remove an adhering to the surface wet film of the conversion solution before the paint is applied. Furthermore, it is usual and may therefore be preferred that the component is dried before the application of the paint. This is the case in particular when a powder coating is to be applied, for which a particularly good paint adhesion base is provided in the method according to the invention and therefore there is a preference.

Ausführungsbeispiele:EXAMPLES

Im Folgenden wird die Korrosionsschutzwirkung einer erfindungsgemäßen Verfahrensabfolge anhand der Vorbehandlung von Aluminiumblechen (EN AW-6014) dargelegt und zudem die Neigung zur Schlammbildung in schwefelsauren Beizlösungen der Vorbehandlungsstufe enthaltend Fluorokomplexe des Elements Titan und 1 g/kg an gelösten Aluminium untersucht.The corrosion protection effect of a process sequence according to the invention is described below on the basis of the pretreatment of aluminum sheets (EN AW-6014) and, in addition, the tendency for sludge formation in sulfuric acid pickling solutions of the pretreatment stage containing fluorocomplexes of the element titanium and 1 g / kg of dissolved aluminum is investigated.

Die Verfahrensabfolge zur Behandlung der Aluminiumbleche (EN AW-6014) beinhaltete die aufeinanderfolgenden Verfahrensschritte I bis IV, wobei jedem der Verfahrensschritte I-III ein Spülschritt mit entionisierten Wasser (κ<1 µScm-1) folgte und die Bleche nach dem Spülschritt nach Verfahrensschritt III im Luftstrom getrocknet wurden, ehe die Lackierung im Schritt IV vorgenommen wurde:
I. Reinigung:

  • 30 g/LBONDERITE C-AK G 414 (Henkel AG & Co. KGaA) in Stadtwasser
  • In-Kontakt-Bringen erfolgt durch Sprühen für 160 Sekunden bei 60 °C und 1 bar

II. Beize:
  • Schwefelsaure wässrige Lösung mit einem pH-Wert von 1,6 enthaltend 4,4 g/kg Al2(SO4)3·14 H2O und zusätzlich
    1. a. 0,5 g/kg H2TiF6
    2. b. 0,5 g/kg H2TiF6 / 1,3 g/kg Zitronensäure
  • In-Kontakt-Bringen erfolgt durch Sprühen für 160 Sekunden bei 50 °C und 1 bar

III. Konversionsbehandlung
30 g/L BONDERITE M-NT 4595 R5 MU (Henkel AG & Co. KGaA) in entionisiertem Wasser (κ<1 µScm-1) ergebend eine Behandlungslösung enthaltend 100 mg/kg H2ZrF6, wobei ein pH-Wert von 2,8 mittels NH4CO3-Lösung eingestellt wurde.
IV. Lackierung
Pulverlack Freiotherm PO1857B plus Klarlack Freiotherm KO1853KRA999 (beide Emil Frei GmbH & Co. KG):
  • Auftragsmenge des Pulverlacks betrug ca. 90 g/m2 und nach dem Einbrennen für 10 Minuten bei 180 °C ergab sich eine Trockenfilmdicke von ca. 60 µm.
  • Auftragsmenge des Klarlacks betrug ca. 50 g/m2 und Einbrennen für 10 Minuten bei 150 °C ergab eine Trockenfilmdicke von ca. 20 µm
Tab. 1 Korrosionswerte auf Aluminiumblechen (EN AW-6014) nach Lackschichtaufbau No. Verfahrensabfolge CASS-Test1 Schlamm3 Unterwanderung am Ritz 2 / mm Enthaftung am Ritz 2 / mm 1 I-IIa-III-IV 0,2 0,2 ja 2 I-IIb-III-IV 0,1 0,1 nein 1 bestimmt nach 240 Stunden im CASS-Test gemäß DIN EN ISO 9227 2 U/2 Wert 3 sichtbare Sedimentbildung in einem 3 l Becherglas mit Außendurchmesser von 150 mm enthaltend 2 Liter der Beizlösung 24 Stunden nach Ansatz der Beizlösung (ja/nein) The process sequence for the treatment of the aluminum sheets (EN AW-6014) involved the successive process steps I to IV, wherein each of the process steps I-III, a rinsing step with deionized water (κ <1 μScm -1 ) followed and the sheets after the rinsing step after process step III air-dried before painting in step IV:
I. Cleaning:
  • 30 g / LBONDERITE C-AK G 414 (Henkel AG & Co. KGaA) in town water
  • Contacting is done by spraying for 160 seconds at 60 ° C and 1 bar

II. Pickling:
  • Sulfuric acid aqueous solution with a pH of 1.6 containing 4.4 g / kg Al 2 (SO 4 ) 3 · 14 H 2 O and in addition
    1. a. 0.5 g / kg H 2 TiF 6
    2. b. 0.5 g / kg H 2 TiF 6 / 1.3 g / kg citric acid
  • Contacting is done by spraying for 160 seconds at 50 ° C and 1 bar

III. conversion treatment
30 g / L BONDERITE M-NT 4595 R5 MU (Henkel AG & Co. KGaA) in deionized water (κ <1 μScm -1 ) resulting in a treatment solution containing 100 mg / kg H 2 ZrF 6 , wherein a pH of 2 8 was adjusted by means of NH 4 CO 3 solution.
IV. Paint
Powder coating Freiotherm PO1857B plus Clearcoat Freiotherm KO1853KRA999 (both Emil Frei GmbH & Co. KG):
  • Application amount of the powder coating was about 90 g / m 2 and after baking for 10 minutes at 180 ° C resulted in a dry film thickness of about 60 microns.
  • Application amount of the clearcoat was about 50 g / m 2 and baking for 10 minutes at 150 ° C gave a dry film thickness of about 20 microns
Tab. 1 Corrosion values on aluminum sheets (EN AW-6014) after paint coat build-up No. process sequence CASS test 1 Mud 3 Infiltration at the Ritz 2 / mm Delamination at the Ritz 2 / mm 1 I-IIa-III-IV 0.2 0.2 Yes 2 I-IIb-III-IV 0.1 0.1 No 1 determined after 240 hours in the CASS test according to DIN EN ISO 9227 2 U / 2 value 3 visible sediment formation in a 3 l beaker with an outer diameter of 150 mm containing 2 liters of the pickling solution 24 hours after pickling solution has been applied (yes / no)

Die Ergebnisse der Tabelle 1 belegen anhand der insgesamt niedrigen Unterwanderungswerte den Vorteil einer Verfahrensführung, bei der der Beizlösung Fluorokomplexe des Elements Ti hinzugesetzt sind. Zusätzlich zu den sehr guten Korrosionsschutzergebnissen im CASS-Test, insbesondere in Gegenwart der Zitronensäure, wird in derartigen Beizlösungen die Schlammbildung durch die Zugabe von Zitronensäure effektiv verhindert. Tab. 2 Schlammbildung in der Beizlösung in Gegenwart unterschiedlicher Inhibitoren Inhibitor Schlammbildung 1 Polyacrylsäure ja Xanthan ja Maleinsäure ja Malonsäure ja Bernsteinsäure ja Mandelsäure ja Milchsäure ja Zitronensäure nein Weinsäure nein Glukonsäure ja Methansulfonsäure ja Amidosulfonsäure ja 1 Bildung eines Sediments in einem 3 l Becherglas mit Außendurchmesser von 150 mm enthaltend 2 Liter der Beizlösung nach 24 Stunden sichtbar (ja/nein) The results of Table 1 show, on the basis of the overall low undercrossing values, the advantage of a process procedure in which the etching solution contains fluorochemical complexes of Ti. In addition to the very good corrosion protection results in the CASS test, especially in the presence of citric acid, in such pickling solutions sludge formation is effectively prevented by the addition of citric acid. Tab. 2 Sludge formation in the pickling solution in the presence of different inhibitors inhibitor Mud formation 1 polyacrylic acid Yes xanthan Yes maleic Yes malonic Yes Succinic acid Yes mandelic Yes lactic acid Yes citric acid No tartaric acid No gluconic Yes methane Yes amidosulfonic Yes 1 formation of a sediment in a 3 l beaker with an outer diameter of 150 mm containing 2 liters of the pickling solution visible after 24 hours (yes / no)

Die schlamminhibierende Wirkung der mehrbasigen α-Hydoxycarbonsäuren ist in der Tabelle 2 veranschaulicht, die die Schlammbildung in einer Beizlösung gemäß obigen Verfahrensschritt II, der jedoch insgesamt 1 g/kg Aluminium-Ionen in Form von Aluminiumsulfat hinzugesetzt sind, beurteilt. Aus dieser Tabelle geht hervor, dass eine Inhibierung der Schlammbildung, also der Ausfällung von Aluminium- und Titan-Salzen, in Gegenwart von Zitronensäure oder Weinsäure gelingt.The sludge-inhibiting effect of the polybasic α-hydroxycarboxylic acids is illustrated in Table 2, which assesses the sludge formation in a pickling solution according to the above process step II, but added a total of 1 g / kg of aluminum ions in the form of aluminum sulfate. From this table shows that an inhibition of sludge formation, ie the precipitation of aluminum and titanium salts, succeed in the presence of citric acid or tartaric acid.

Claims (15)

  1. A method for the anti-corrosion treatment of components made of aluminum, comprising a pretreatment stage and subsequent coating, in which method, in the pretreatment stage, the component is first brought into contact with an aqueous phosphate-free sulfuric acid pickling solution which has a pH of from 1 to 2.5, a free acid content of at least 5 points and contains at least one water-soluble compound of the element Ti, a source of fluoride ions and at least one polybasic α-hydroxycarboxylic acid, and is subsequently brought into contact with an aqueous conversion treatment solution which has a pH of from 1 to 3.5 and contains at least one water-soluble compound of the elements Zr and/or Ti.
  2. The method according to claim 1, characterized in that the proportion of α-hydroxycarboxylic acids in the pickling solution is at least 0.1 g/kg, preferably at least 0.5 g/kg, particularly preferably at least 1 g/kg, but preferably does not exceed 4 g/kg, particularly preferably does not exceed 2 g/kg.
  3. The method according to one or both of the preceding claims, characterized in that the α-hydroxycarboxylic acids in the pickling solution are selected from citric acid and/or tartaric acid, preferably from citric acid.
  4. The method according to one or more of the preceding claims, characterized in that the proportion of water-soluble compounds of the element Ti in the pickling solution is at least 0.04 g/kg, preferably at least 0.1 g/kg, but preferably does not exceed 0.6 g/kg, particularly preferably does not exceed 0.3 g/kg, in each case based on the element Ti.
  5. The method according to one or more of the preceding claims, characterized in that the pickling solution has a pH below 2.
  6. The method according to one or more of the preceding claims, characterized in that the pickling solution has a free acid content of at least 6 points, but preferably no more than 10 points.
  7. The method according to one or more of the preceding claims, characterized in that the pickling solution has a total acid content of at least 12 points, but preferably no more than 18 points.
  8. The method according to one or more of the preceding claims, characterized in that the proportion of water-soluble compounds of the elements Zr and/or Ti in the conversion treatment solution is at least 0.1 mmol/kg, preferably at least 0.5 mmol/kg, but preferably does not exceed 5 mmol/kg, particularly preferably does not exceed 3 mmol/kg, calculated in each case as corresponding amounts of the elements Zr and/or Ti.
  9. The method according to one or more of the preceding claims, characterized in that the water-soluble compounds of the elements Zr and/or Ti are selected from water-soluble compounds of the element Zr, which are in turn preferably selected from hexafluorozirconic acid and the salts thereof.
  10. The method according to one or more of the preceding claims, characterized in that the component is brought into contact with the pickling solution for long enough to pickle at least 2 mg of aluminum per square meter of the surface of the component that has been brought into contact, and to preferably also at least produce a coating layer of at least 4 mg of titanium per square meter of the surface of the component that has been brought into contact.
  11. The method according to one or more of the preceding claims, characterized in that, before being brought into contact with the pickling solution, the component undergoes alkaline degreasing, preferably by being brought into contact with an alkaline aqueous composition which has a pH of greater than 9, but preferably less than 12, and a free alkalinity of at least 3 points but preferably less than 6 points and which optionally contains surface-active compounds which are preferably selected from non-ionic surfactants.
  12. The method according to claim 11, characterized in that, after the alkaline degreasing and before being brought into contact with the pickling solution, a rinsing step, but preferably not a drying step, takes place.
  13. The method according to one or more of the preceding claims, characterized in that, after being brought into contact with the pickling solution and before being brought into contact with the conversion treatment solution, a rinsing step, but preferably not a drying step, takes place.
  14. The method according to one or more of the preceding claims, characterized in that, after being brought into contact with the conversion treatment solution and before being coated, a rinsing step takes place, and immediately before being coated, a drying step preferably also takes place.
  15. The method according to one or more of the preceding claims, characterized in that the component is coated in the subsequent coating with a powder coating.
EP17191578.8A 2017-09-18 2017-09-18 Two stage pre-treatment of aluminium, in particular aluminium casting alloys, comprising a pickle and a conversion treatment Active EP3456864B1 (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
ES17191578T ES2767852T3 (en) 2017-09-18 2017-09-18 Two-stage aluminum pretreatment, in particular aluminum alloys, comprising pickling and conversion treatment
PL17191578T PL3456864T3 (en) 2017-09-18 2017-09-18 Two stage pre-treatment of aluminium, in particular aluminium casting alloys, comprising a pickle and a conversion treatment
EP17191578.8A EP3456864B1 (en) 2017-09-18 2017-09-18 Two stage pre-treatment of aluminium, in particular aluminium casting alloys, comprising a pickle and a conversion treatment
HUE17191578A HUE048447T2 (en) 2017-09-18 2017-09-18 Two stage pre-treatment of aluminium, in particular aluminium casting alloys, comprising a pickle and a conversion treatment
MX2020001673A MX2020001673A (en) 2017-09-18 2018-06-26 Two-stage pre-treatment of aluminum, in particular aluminum casting alloys, comprising pickle and conversion treatment.
CN201880060188.5A CN111094624B (en) 2017-09-18 2018-06-26 Two-stage pretreatment of aluminum, particularly cast aluminum alloys, including pickling and conversion treatment
KR1020207007534A KR102538202B1 (en) 2017-09-18 2018-06-26 Two-step pretreatment of aluminum, particularly aluminum casting alloys, including pickling and conversion treatment
PCT/EP2018/067027 WO2019052701A1 (en) 2017-09-18 2018-06-26 Two-stage pre-treatment of aluminum, in particular aluminum casting alloys, comprising pickle and conversion treatment
US16/817,044 US11499237B2 (en) 2017-09-18 2020-03-12 Two-stage pretreatment of aluminum, in particular aluminum casting alloys, comprising pickle and conversion treatment

Applications Claiming Priority (1)

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EP17191578.8A EP3456864B1 (en) 2017-09-18 2017-09-18 Two stage pre-treatment of aluminium, in particular aluminium casting alloys, comprising a pickle and a conversion treatment

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MX (1) MX2020001673A (en)
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CN114622196B (en) * 2021-11-11 2022-11-29 四川亨通兴达科技有限公司 Environment-friendly nano vitrification agent for surface treatment based on phosphorus-free metal and preparation method thereof

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JPS5173938A (en) * 1974-12-25 1976-06-26 Nippon Packaging Kk Aruminiumuoyobi sonogokinnohyomenshoriho
DE4317217A1 (en) 1993-05-24 1994-12-01 Henkel Kgaa Chrome-free conversion treatment of aluminum
DE19921842A1 (en) 1999-05-11 2000-11-16 Metallgesellschaft Ag Pretreatment of aluminum surfaces with chrome-free solutions
US6821633B2 (en) 2002-05-17 2004-11-23 Henkel Kommanditgesellschaft Auf Aktien (Henkel Kgaa) Non-chromate conversion coating compositions, process for conversion coating metals, and articles so coated
GB0500071D0 (en) * 2005-01-05 2005-02-09 Houghton Australia Pty Ltd Cleaning formulation
CN101463475A (en) * 2007-12-19 2009-06-24 鸿富锦精密工业(深圳)有限公司 Magnesium alloy phosphating method and formation solution thereof
DE102012215679A1 (en) * 2012-09-04 2014-05-15 Henkel Ag & Co. Kgaa Process for the corrosion-protective surface treatment of metallic components in series
WO2015052546A1 (en) * 2013-10-09 2015-04-16 ArcelorMittal Investigación y Desarrollo, S.L. Sheet metal having a znaimg coating and improved flexibility and corresponding production method
DE102014206407A1 (en) * 2014-04-03 2015-10-08 Henkel Ag & Co. Kgaa Two-stage pre-treatment of aluminum including pickle and passivation

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HUE048447T2 (en) 2020-08-28
US20200208273A1 (en) 2020-07-02
MX2020001673A (en) 2020-07-13
US11499237B2 (en) 2022-11-15
WO2019052701A1 (en) 2019-03-21
CN111094624B (en) 2023-01-24
PL3456864T3 (en) 2020-05-18
KR20200054974A (en) 2020-05-20
KR102538202B1 (en) 2023-05-30
CN111094624A (en) 2020-05-01
ES2767852T3 (en) 2020-06-18

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