Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/07—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing phosphates
  • C23C22/08—Orthophosphates
  • C23C22/12—Orthophosphates containing zinc cations
  • C23C22/17—Orthophosphates containing zinc cations containing also organic acids
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/82—After-treatment
  • C23C22/83—Chemical after-treatment
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2222/00—Aspects relating to chemical surface treatment of metallic material by reaction of the surface with a reactive medium
  • C23C2222/10—Use of solutions containing trivalent chromium but free of hexavalent chromium

Definitions

• the invention relates to the corrosion protection of metallic materials, in particular of those which are provided with a surface of zinc or zinc alloys.
• the coating of the metallic workpiece to be protected with a coating of another metal is a widely used and established method in the art.
• the coating metal can behave in the corrosive medium either electrochemically nobler or less noble than the material base metal. If the coating metal behaves less noble, it acts in the corrosive medium compared to the base metal as a sacrificial anode (cathodic corrosion protection).
• this protective function associated with the formation of corrosion products of the coating metal is thus desired, the corrosion products of the coating often lead to undesirable decorative and often also to functional impairments of the workpiece.
• cathodically protective base coating metals such as, for example, Zinc or aluminum and their alloys often used so-called conversion coatings.
• conversion coatings These are reaction products of the non-noble coating metal which are insoluble in aqueous media over a wide pH range with the treatment solution. Examples of these so-called conversion layers are so-called phosphating and chromating.
• chromium (VI) ions see EP 0 553 164 A1 .
• chromium (VI) is reduced to chromium (III), which in the surface film which is more alkaline due to the evolution of hydrogen, inter alia as chromium (III) hydroxide or sparingly soluble ⁇ -oxo or ⁇ -hydroxo bridging Chromium (III) complex is deposited.
• chromium (III) hydroxide or sparingly soluble ⁇ -oxo or ⁇ -hydroxo bridging Chromium (III) complex is deposited.
• sparingly soluble zinc chromate (VI) is formed. Overall, a tightly closed, very well protects against corrosion attack by electrolytes conversion coating on the zinc surface.
• chromium (VI) compounds are acutely toxic and highly carcinogenic, requiring replacement of the methods associated with these compounds.
• a disadvantage of this additional process step is the occurrence of drainage drops in the coating of workpieces made on the frame and / or the bonding of coated bulk material; In addition, problems such as dimensional accuracy of threads and the like, which are associated with the layer thickness of these seals arise.
• the font EP 0 479 289 A1 describes a chromating process in which the substrates are immersed in a treatment solution containing, in addition to chromium (VI) and chromium (III) ions, hydrofluoric acid and phosphoric acid, a silane coupling agent.
• the patent EP 0 922 785 B1 describes a treatment solution and a process for the production of protective layers on metals, wherein the surface to be protected with a treatment solution containing chromium (III) ions, an oxidizing agent and an oxyacid or an oxyacid salt of phosphorus or a corresponding anhydride.
• This treating solution may further contain a monomeric silane coupling agent.
• EP 1 051 539 B1 describes a treatment solution for increasing the corrosion protection of substrates which, in addition to chromium (VI) and chromium (III) ions, also contains phosphoric acid, hydrofluoric acid, colloidal silicon dioxide and a monomeric epoxy-functionalized silane.
• the invention has for its object to provide methods for increasing the corrosion protection of metallic, especially zinc-containing and zinc-containing, provided with a conversion layer, surfaces.
• the aim is to preserve or improve the decorative and functional properties of the surfaces.
• the above problems with the use of chromium (VI) -containing compounds and hydrofluoric acid or post-treatments for sealing are to be avoided.
• the process of applying a chromium (III) ion-containing passivation step, which is usually carried out in two separate stages, followed by a sealing is to be replaced by a one-stage process in which the functionality of a passivation layer containing chromium (III) ions and a sealant are united.
• a further aspect of the invention is that it is possible to dispense with the rinsing steps which are usually required in the two-stage processes known from the prior art between the application of the passivation containing chromium (III) ions and the sealing. This significantly reduces the amount of heavy metal contaminated wastewater. Furthermore, the handling of silanes and other metal alkoxides should be made controllable by separately prepared under appropriate reaction conditions organosols of sufficient stability and film-forming properties and then only with the remaining components of the treatment solution (chromium (III) ions, phosphate source and other optional components) be mixed.
• Phosphate compounds are derived from phosphorus in the oxidation state + V derived oxo compounds and their esters with organic radicals having up to 12 carbon atoms and the salts of mono- and diesters.
• Suitable phosphate compounds are in particular alkyl phosphates with alkyl groups having up to 12 carbon atoms.
• Suitable phosphate compounds are ortho-phosphoric acid (H 3 PO 4 ) and its salts, polyphosphoric acid and its salts, meta-phosphoric acid and its salts, phosphoric acid methyl ester (mono-, di- and triesters), phosphoric acid ethyl ester (mono-, Di- and triesters), n -propyl phosphoric acid esters (mono-, di- and triesters), isopropyl orthophosphate (mono-, di- and triesters), n- butyl phosphate (mono-, di- and triesters), phosphoric acid-2 butyl ester (mono-, di- and triester), phosphoric acid tert- butyl ester (mono-, di- and triester), the salts of said mono- and diesters and di-phosphorus pentoxide and mixtures of these compounds.
• sets includes not only the salts of completely deprotonated acids, but salts in all possible proto
• the treatment solution preferably contains between 0.2 g / l and 20 g / l of chromium (III) ions, more preferably between 0.5 g / l and 15 g / l of chromium (III) ions and more preferably between 1 g / l and 10 g / l chromium (III) ions.
• the ratio of the molar concentration of chromium (III) ions to the molar concentration of the at least one phosphate compound (based on orthophosphate) is between 1: 1.5 and 1: 3, preferably between 1: 1.7 and 1: 2.5.
• Chromium (III) ions may be added to the treatment solution either in the form of inorganic chromium (III) salts, e.g. basic chromium (III) sulfate, chromium (III) hydroxide, chromium (III) dihydrogen phosphate, chromium (III) chloride, chromium (III) nitrate, potassium chromium (III) sulfate or chromium (III) salts organic Acids such as Chromium (III) methanesulfonate, chromium (III) citrate may be added or produced by reduction of suitable chromium (VI) compounds in the presence of suitable reducing agents.
• inorganic chromium (III) salts e.g. basic chromium (III) sulfate, chromium (III) hydroxide, chromium (III) dihydrogen phosphate, chromium (III) chloride, chromium (III) n
• Suitable chromium (VI) compounds are e.g. Chromium (VI) oxide, chromates, such as potassium or sodium chromate, dichromates, e.g. Potassium or sodium dichromate.
• Suitable reducing agents for in situ generation of chromium (III) ions are e.g. Sulfites, e.g. Sodium sulfite, sulfur dioxide, phosphites, e.g. Sodium hypophosphite, phosphorous acid, hydrogen peroxide, methanol, hydroxycarboxylic acids and hydroxydicarboxylic acids, e.g. Gluconic acid, citric acid and malic acid.
• the treatment solution preferably has a pH between pH 2 and pH 7, more preferably between pH 2.5 and pH 6, and most preferably between pH 2.5 and pH 3.
• the above-mentioned organosol can be obtained by per se known hydrolysis and condensation of the at least one alkoxysilane of the formula (1).
• Particularly preferred among the above alkoxysilanes of the formula (1) is at least one in which at least one R has a group which can undergo a polyaddition (including polymerization) or polycondensation reaction.
• This grouping capable of polyaddition or polycondensation reaction is preferably an epoxy group or carbon-carbon multiple bonds, with a (meth) acrylate group being a particularly preferred example of the latter groupings.
• Particularly preferred alkoxysilanes according to formula (1) are those in which x is 2 or 3 and in particular 3 and a radical R is ⁇ -glycidyloxy-C 2-6 -alkyl or ⁇ - (meth) acryloxy-C 2-6 - Alkyl stands.
• alkoxysilanes are 3-glycidoxypropyltri (m) ethoxysilane, 3,4-epoxybutyltri (m) ethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltri (m) ethoxysilane, 3- (meth) acryloxypropyltri (m) ethoxysilane and 2 - (meth) acryloxyethyltri (m) ethoxysilane, 3-glycidoxypropyldimethyl (m) ethoxysilane, 3-glycidoxypropylmethyldi (m) ethoxysilane, 3- (meth) acryloxypropylmethyldi (m) ethoxysilane and 2- (meth) acryloxyethylmethyl-di (m) ethoxysilane.
• alkoxysilanes of the formula (1) which can preferably be used in combination with alkoxysilanes having the above groupings capable of polyaddition or polycondensation reaction are, for example, hexadecyltri (m) ethoxysilane, cyclohexyltri (m) ethoxysilane, cyclopentyltri (m) ethoxysilane, ethyltri (m) ethoxysilane, phenylethyltri (m) ethoxysilane, phenyltri (m) ethoxysilane, n-propyltri (m) ethoxysilane, cyclohexyl (m) ethyldimethoxysilane, dimethyldi (m) ethoxysilane, diisopropyldi (m) ethoxysilane and phenylmethyldi (m) ethoxysilane.
• At least one alkoxide according to formula (2) is then combined with the hydrolyzate of the at least one alkoxysilane of formula (1).
• the Alkoxides according to formula (2) are very reactive, so that in the absence of a complexing agent, the components according to formulas (1) and (2) would hydrolyze and condense very rapidly on contact with water. According to the invention, however, it is not necessary to use the reactive alkoxides directly in complexed form. Rather, it is possible to add the complexing agent or compounds shortly after the start of the reaction of the components according to formulas (1) and (2).
• alkoxides according to formula (2) are aluminum sec-butoxide, titanium isopropoxide, titanium propoxide, titanium butoxide, zirconium isopropoxide, zirconium propoxide, zirconium butoxide, zirconium ethoxide, tetraethoxysilane, tetramethoxysilane, tetrapropyloxysilane and tetrabutyloxysilane.
• complexing agents are ethanolamines and alkyl phosphates, such as tri-, diethanolamine and butyl phosphate.
• examples of such complexed alkoxides according to formula (2) are titanium acetylacetonates, titanium bisacetoacetates, triethanolamine titanates, triethanolamine zirconates and zirconium diethyl citrates.
• the complexing agent in particular a chelate compound, causes some complexation of the metal cation, so that the hydrolysis and condensation rate of the components according to formulas (1) and (2) is reduced.
• the organosol comprises a water-compatible or water-miscible solvent having a boiling point of at least 150 ° C.
• a water-compatible or water-miscible solvent having a boiling point of at least 150 ° C.
• diethylene glycol, triethylene glycol, butyl diglycol, propylene glycols, butylene glycols, and polyethylene glycols can be used therefor.
• the object of the high-boiling solvents is that improved resistance of the organosols can be achieved in exchange for the liberated during hydrolysis low molecular weight alcohol.
• the organosol is characterized in that the weight ratio of the component according to formula (1) to the component according to formula (2) in the range 1: 1 to 1: 100, especially preferably in the range 1: 1 to 1: 25. Since the components according to formula (2) also serve as crosslinking agents for the alkoxysilanes according to formula (1), they should be present in the organosols at least in equimolar amounts relative to the component of formula (1).
• the organosol is the treatment solution according to the invention based on an active ingredient content of 25% in the organosol in an amount of 1 g / l to 50 g / l, preferably 3 g / l to 20 g / l and most preferably 5 g / l to 15 g / l added.
• the treatment solution may additionally (optionally) contain one or more further complexing agents.
• Suitable further complexing agents are, in particular, organic chelate ligands.
• suitable further complexing agents are polycarboxylic acids, hydroxycarboxylic acids, hydroxypolycarboxylic acids, aminocarboxylic acids or hydroxyphosphonic acids.
• suitable carboxylic acids are citric, tartaric, malic, lactic, gluconic, glucuronic, ascorbic, isocitric, gallic, glycolic, 3-hydroxypropionic, 4-hydroxybutyric, salicylic, nicotinic, alanine, glycine, asparagine, aspartic, cysteine, glutamic, glutamine , Lysine.
• Suitable hydroxyphosphonic acids are, for example, Dequest 2010 TM (from Solutia, Inc.); suitable as aminophosphonic acids, for example Dequest 2000 TM (from Solutia, Inc.).
• the treatment solution will contain at least one metal or metalloid, e.g. Sc, Y, Ti, Zr, Mo, W, Mn, Fe, Co, Ni, Zn, B, Al, Si.
• metal or metalloid e.g. Sc, Y, Ti, Zr, Mo, W, Mn, Fe, Co, Ni, Zn, B, Al, Si.
• These elements may be added in the form of their salts or in the form of complex anions or the corresponding acids of these anions such as hexafluoroboric acid, hexafluorosilicic acid, hexafluorotitanic acid or hexafluorozirconic acid, tetrafluoroboric acid or hexafluorophosphoric acid or their salts.
• zinc which may be added in the form of zinc (II) salts, for example zinc sulfate, zinc chloride, zinc phosphate, zinc oxide or zinc hydroxide.
• the treatment solution is added between 0.5 g / l and 25 g / l, more preferably between 1 g / l and 15 g / l Zn 2+ .
• the list of zinc compounds are only examples of compounds suitable according to the invention, but does not limit the amount of suitable zinc compounds to the substances mentioned.
• the treatment solution may additionally (optionally) contain one or more water-soluble or water-dispersible polymers selected from the group consisting of polyethylene glycols, polyvinylpyrrolidones, polyvinyl alcohols to improve the film formation on the surface to be treated and to increase the hydrophobicity of the surface.
• polyethylene glycols polyvinylpyrrolidones
• polyvinyl alcohols polyvinyl alcohols
• the concentration of the at least one polymer is preferably in the range between 50 mg / l and 20 g / l.
• the layer properties of the deposited corrosion protection layer are significantly improved.
• the treatment solution may additionally (optionally) contain one or more wetting agents.
• one or more wetting agents may additionally (optionally) contain one or more wetting agents.
• fluoroaliphatic polymeric esters such as Fluorad FC-4432 TM (from 3M).
• the treatment solution may additionally (optionally) contain one or more lubricants.
• Suitable lubricants are, for example, polyether-modified siloxanes, polyether wax emulsions, ethoxylated alcohols, PTFE, PVDF, ethylene copolymers, paraffin emulsions, polypropylene wax emulsions, MoS 2 and dispersions thereof, WS 2 and emulsions thereof, polyethylene glycols, polypropylene, Fischer-Tropsch hard waxes, micronized and synthetic hard waxes, Graphite, metal soaps and polyurea.
• Particularly preferred lubricants are PTFE, micronized hard waxes and polyether wax emulsions.
• the optional lubricants are added in an amount of 0.1 g / l to 300 g / l, preferably 1 g / l to 30 g / l of the treatment solution according to the invention.
• the surfaces treated according to the invention are metallic, preferably zinc-containing, and zinc-containing surfaces which are optionally provided with a chromium (III) -containing conversion layer.
• the process according to the invention deposits on the treated surface a layer comprising chromium (III) ions, phosphate (s), a silicon / metal organic network and optionally further metal ions, e.g. Zinc ions, and optionally one or more polymeric components.
• the contacting of the treatment solution with the surface to be treated can be carried out in the inventive method according to known methods, in particular by immersion.
• the temperature of the treatment solution is preferably between 10 ° C and 90 ° C, more preferably between 20 ° C and 80 ° C, more preferably between 25 ° C and 50 ° C.
• the duration of the contacting is preferably between 0.5 s and 180 s, more preferably between 5 s and 60 s, most preferably between 10 s and 30 s.
• the treatment solution can be prepared prior to carrying out the method according to the invention by dilution of a correspondingly higher concentrated concentrate solution.
• the objects treated according to the invention are no longer rinsed after contacting, but are dried directly.
• the process according to the invention leads to increased corrosion protection in the case of articles which have a zinc-containing surface.
• the method of the invention may also be used.
• the method according to the invention after application of a so-called conversion layer is applied to full metal zinc and zinc alloy surfaces.
• Conversion layers can be deposited from treatment solutions containing, for example, chromium (III) ions and an oxidizing agent.
• the method of the present invention is applied to full metal zinc and zinc alloy surfaces after oxidative activation.
• This oxidative activation is, for example, immersing the galvanized substrate in an aqueous solution containing an oxidizing agent.
• Suitable oxidizing agents for this purpose are nitrates and nitric acid, peroxides such as hydrogen peroxide, persulfates and perborates.
• zinc flake coatings the process according to the invention is applied directly after application and curing of the zinc flake coating.
• Sample parts made of steel were first coated in a weakly acidic electroplating process (Unizinc ACZ 570 from Atotech GmbH) with an 8-10 ⁇ m thick zinc coating and rinsed with demineralized water.
• a weakly acidic electroplating process Unizinc ACZ 570 from Atotech GmbH
• sample parts were provided with a chromium (III) ion and nitrate-containing conversion layer (EcoTri® HC2 from Atotech Deutschland GmbH) and dried.
• a chromium (III) ion and nitrate-containing conversion layer (EcoTri® HC2 from Atotech Deutschland GmbH)
• treatment solution A a treatment solution with a pH of 3.9 was applied, which contained the following constituents: 4.5 g / l Cr 3+ from chromium (III) hydroxide 18 g / l PO 4 3- from ortho-phosphoric acid 5.5 g / l Zn 2+ from zinc oxide 11 g / l citric acid
• the corrosion resistance formation of red corrosion according to EN ISO 9227 was tested with a neutral salt spray test. The formation of red corrosion was observed after 864 h.
• Sample parts made of steel were coated in a weakly acidic galvanic process (Unizinc ACZ 570 from Atotech GmbH) with an 8-10 ⁇ m thick zinc coating and rinsed with demineralized water.
• a weakly acidic galvanic process Unizinc ACZ 570 from Atotech GmbH
• sample parts were provided with a chromium (III) ion and nitrate-containing conversion layer (EcoTri®HC2 from Atotech Deutschland GmbH) and dried.
• a chromium (III) ion and nitrate-containing conversion layer (EcoTri®HC2 from Atotech Deutschland GmbH)
• a treatment solution according to the invention with a pH value of 2.8 was applied, which contained the following constituents: 4.5 g / l Cr 3+ from chromium (III) hydroxide 18 g / l PO 4 3- from ortho-phosphoric acid 5.5 g / l Zn 2+ from zinc oxide 11 g / l citric acid 50 g / l an organosol having an active substance content of 25% (in% by weight) prepared from tetraethoxysilane as alkoxysilane according to formula (1) and 3-glycidyloxypropyltriethoxysilane as metal alkoxide according to formula (2).
• the corrosion resistance formation of red corrosion according to EN ISO 9227 was tested with a neutral salt spray test. The formation of red corrosion was observed after 1500 h.
• Sample parts made of steel were coated with a zinc flake-containing treatment solution (Zintek® 800 WD 1 from Atotech Deutschland GmbH) with a 10 ⁇ m thick zinc flake-containing overlay.
• a zinc flake-containing treatment solution Zintek® 800 WD 1 from Atotech GmbH
• Example 1 the treatment solution of Example 1 according to the invention was applied and the sample parts coated in this way were dried.
• the corrosion resistance formation of red corrosion according to EN ISO 9227 was tested with a neutral salt spray test. The formation of red corrosion was observed after 3500 hours.

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• 2009
  • 2009-07-03 EP EP09164575A patent/EP2281923A1/fr not_active Withdrawn
• 2010
  • 2010-07-05 JP JP2012518952A patent/JP5627680B2/ja active Active
  • 2010-07-05 CN CN201080029167.0A patent/CN102471890B/zh active Active
  • 2010-07-05 ES ES10728680T patent/ES2401173T3/es active Active
  • 2010-07-05 WO PCT/EP2010/059586 patent/WO2011000969A1/fr active Application Filing
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