EP0646187B1 - Couche d'oxyde non chromate pour substrats en aluminium - Google Patents

Couche d'oxyde non chromate pour substrats en aluminium Download PDF

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EP0646187B1
EP0646187B1 EP93914728A EP93914728A EP0646187B1 EP 0646187 B1 EP0646187 B1 EP 0646187B1 EP 93914728 A EP93914728 A EP 93914728A EP 93914728 A EP93914728 A EP 93914728A EP 0646187 B1 EP0646187 B1 EP 0646187B1
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cobalt
solution
salt
substrate
per liter
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German (de)
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EP0646187A1 (fr
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Matthias P. Schriever
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Boeing Co
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Boeing Co
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    • 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
    • C23C22/48—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 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
    • C23C22/56—Treatment of aluminium or alloys based thereon
    • 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
    • C23C22/60—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 alkaline aqueous solutions with pH greater than 8
    • C23C22/66—Treatment of aluminium or alloys based thereon
    • 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
    • C23C22/68—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 solutions with pH between 6 and 8

Definitions

  • This environmental-quality invention is in the field of chemical conversion coatings formed on metal substrates, for example, on aluminum substrates. More particularly, one aspect of the invention is a new type of oxide coating (which I refer to as a "cobalt conversion coating") which is chemically formed on metal substrates.
  • the invention enhances the quality of the environment of mankind by contributing to the maintenance of air and water quality.
  • chemical conversion coatings are formed chemically by causing the surface of the metal to be "converted" into a tightly adherent coating, all or part of which consists of an oxidized form of the substrate metal.
  • Chemical conversion coatings can provide high corrosion resistance as well as strong bonding affinity for paint.
  • the industrial application of paint (organic finishes) to metals generally requires the use of a chemical conversion coating, particularly when the performance demands are high.
  • aluminum protects itself against corrosion by forming a natural oxide coating, the protection is not complete.
  • aluminum alloys particularly of the high-copper 2000-series aluminum alloys, such as alloy 2024-T3, corrode much more rapidly than pure aluminum.
  • the first is by anodic oxidation (anodization) in which the aluminum component is immersed in a chemical bath, such as a chromic or sulfuric acid bath, and an electric current is passed through the aluminum component and the chemical bath.
  • a chemical bath such as a chromic or sulfuric acid bath
  • an electric current is passed through the aluminum component and the chemical bath.
  • the resulting conversion coating on the surface of the aluminum component offers resistance to corrosion and a bonding surface for organic finishes.
  • the second type of process is by chemically producing a conversion coating, which is commonly referred to as a chemical conversion coating, by subjecting the aluminum component to a chemical solution, such as a chromic acid solution, but without using an electric current in the process.
  • a chemical solution such as a chromic acid solution
  • the chemical solution may be applied by immersion application, by manual application, or by spray application.
  • the resulting conversion coating on the surface of the aluminum component offers resistance to corrosion and a bonding surface for organic finishes.
  • the present invention relates to this second type of process for producing chemical conversion coatings.
  • the chemical solution may be applied by immersion application, by various types of manual application, or by spray application.
  • chromic acid process for forming chemical conversion coatings on aluminum substrates is described in various embodiments in Ostrader et al. U.S. Patent 2,796,370 and Ostrader et al. U.S. Patent 2,796,371, in military process specification MIL-C-5541, and in Boeing Process Specification BAC 5719.
  • These chromic acid chemical conversion baths contain hexavalent chromium, fluorides, and cyanides, all of which present significant environmental as well as health and safety problems.
  • the constituents of a typical chromic acid conversion bath are as follows: CrO 3 - "chromic acid” (hexavalent, chromium); NaF-sodium fluoride; KBF 4 -potassium tetrafluoroborate; K 2 ZrF 6 -potassium hexafluorozirconate; K 3 Fe(CN) 6 potassium ferricyanide; and, HNO 3 -nitric acid (for pH control).
  • Chromic acid conversion films as formed on aluminum substrates, meet a 168 hours corrosion resistance criterion, but they primarily serve as a surface substrate for paint adhesion. Because of their relative thinness and low coating weights 3.72-13.84 milligrams/m 2 (40-150 milligrams/ft 2 ), chromic acid conversion coatings do not cause a fatigue life reduction in the aluminum structure.
  • the invention is a process for forming a cobalt conversion coating on a metal substrate, thereby imparting corrosion resistance and paint adhesion properties.
  • the invention was developed as a replacement for the prior art chromic acid process.
  • the process includes the steps of: (a) providing a cobalt conversion solution comprising an aqueous solution containing a soluble cobalt-III hexavalent complex, the concentration to the cobalt-III hexavalent complex being from about 0.01 mole per liter of solution to the saturation limit of the cobalt-III hexavalent complex; and (b) contacting the substrate with the solution for a sufficient amount of time, whereby the cobalt conversion coating is formed.
  • the substrate may be aluminum, aluminum alloy, as well as Cd plated, Zn plated, Zn-Ni plated, and steel.
  • the cobalt-III hexavalent complex is preferably present in the form of Me m [Co(R) 6 ] n' wherein Me is Na, Li, K, Ca, Zn, Mg, or Mn, and wherein m is 2 or 3, n is 1 or 2, and R is a carboxylate having 1 to 6 C atoms.
  • the invention is a chemical conversion coating solution for producing a cobalt conversion coating on a metal substrate, the solution including an aqueous solution containing a soluble cobalt-III hexacarboxylate complex, the concentration of the cobalt-III hexacarboxylate complex being from about 0.01 mole per liter of solution to the saturation limit of the cobalt-III hexavalent complex.
  • the cobalt conversion solution may be prepared by a bath makeup sequence including the steps of: (a) dissolving a soluble cobalt-II salt, preferably cobalt acetate, and (b) dissolving a metal acetate salt such as sodium, magnesium or calcium acetate to form a conversion coating solution.
  • wetting agents such as alkyl fluorides, fluorocarbons, and metal fluorides can be added to the conversion coating solutions. Addition of these wetting agents eliminate the need for a costly sealing step following formation of the conversion coating.
  • FIGURES 1 through 4 are photomicrographs (scanning electron microscope operated at 20 KV) of alloy 2024-T3 test panels with cobalt conversion coatings made by the invention.
  • FIGURES 1 through 4 show a cobalt conversion coatings 410 formed by a 15 minute immersion in a typical cobalt conversion coating solution at 60°C (140°F).
  • FIGURE 1 is a photomicrograph at X10,000 magnification of a test panel showing a cobalt conversation coating 410 of the invention.
  • the photomicrograph is a top view of the upper surface of oxide coating 410.
  • the top of oxide coating 410 is porous and looks like a sponge. This test panel was immersed in the cobalt conversion coating solution for 15 minutes.
  • the white bar is a length of 1 micron.
  • FIGURE 2 is a photomicrograph at X70,000 magnification of the test panel of FIGURE 1.
  • the photomicrograph is a top view of the upper surface of oxide coating 410.
  • FIGURE 2 is a close-up, at higher magnification, of a small area of the test panel.
  • the white bar is a length of 1 micron.
  • FIGURE 3 is a photomicron at X10,000 magnification of another test panel showing a side view, from an elevated angle, of a fractured cross section of a cobalt conversion coating 420 of the invention.
  • the fractured cross section of the aluminum substrate of the test panel is indicated by reference numeral 422.
  • This test panel was immersed in the coating bath for 15 minutes. To make the photomicrograph, the test panel was bent and broken off to expose a cross section of oxide coating 420.
  • the white bar is a length of 1 micron.
  • FIGURE 4 is a photomicrograph at X70,000 magnification of the test panel of FIGURE 3 showing a side view, from an elevated angle, of a fractured cross section of cobalt conversion coating 420 of the invention.
  • FIGURE 4 is a close-up, at higher magnification, of a small area of the test panel.
  • the aluminum substrate of the test panel is indicated by reference numeral 422.
  • the white bar is a length of 1 ⁇ m.
  • FIGURE 5 is a graph showing the tradeoff between paint adhesion and corrosion resistance as a function of immersion time.
  • the present invention relates to a new cobalt conversion coating.
  • the cobalt conversion coating can be made so resistant to corrosion that the conventional sealing step is no longer required. This result is achieved by adding metal fluorides and wetting agents such as alkyl fluorides and fluorocarbons to the conversion coating solution. It is believed that the combination of the wetting agents and the metal fluorides impart a small etch effect on the aluminum substrate surface which is believed to aid in the coating formation.
  • Cobalt ammine complexes were thus produced with a number of reactants, i.e., Co(NO 3 )• 6H 2 O, CoCl 2 • 6H 2 O, NH 4 NO 3 , NH 4 Cl and NH 4 OH.
  • the resultant coatings formed on aluminum substrates were found to have substantially improved corrosion resistant over the simple salt immersion described earlier.
  • a review of cobalt complexing chemistry yielded the following information:
  • reaction (4) An examination of reaction (4) revealed however, that while well defined iridescent coatings could be formed on aluminum substrates, an excess of ammonia, i.e., NH 4 OH was required to drive this reaction. As a consequence, it is difficult to control the pH of the bath due to the high evaporation rates of ammonia from the solution. Furthermore, the amount of excess ammonia in the bath had a pronounced effect on the paint adhesion and corrosion resistance characteristics of coatings formed by this method. Paint adhesion and corrosion performance ranged from superb to complete failure, depending on the amount of ammonia in the bath.
  • the typical reactions are 2Co(C 2 H 3 O 2 ) 2 • 4H 2 O + 3 Mg(C 2 H 3 O 2 ) 2 • 4H 2 O +2HC 2 H 3 O 2 ⁇ Mg 3 [Co(C 2 H 3 O 2 ) 6 ] 2 + 21H 2 O Co(C 2 H 3 O 2 ) 2 • 4H 2 O + 3Ca(C 2 H 3 O 2 ) 2 • H 2 O +1/2 O 2 + 2HC 2 H 3 O 2 ⁇ Ca 3 [Co(C 2 H 3 O 2 ) 6 ] 2 + 21H 2 O Co(C 2 H 3 O 2 ) 2 • 4H 2 O + 3Na(C 2 H 3 O 2 ) • 3H 2 O + 1/4O 2 + HC 2 H 3 O 2 ⁇ Na 3 [Co(C 2 H 3 O 2 ) 6 ] + 13 1/2H 2 O
  • a cobalt conversion coating having superior performance characteristics can be produced by reacting a soluble cobalt salt with a metal carboxylate in accordance with the following general formula Soluble Cobalt Salt + Me(R) x ⁇ Me m [Co(R) 6 ] n , wherein x can be 1 or 2, m is 3, n is 1 or 2, Me is selected from the group consisting of Na, Li, K, Ca, Zn, Mg, and Mn, and wherein R is a carboxylate having from 1 to 5 carbon (C) atoms, provided the carboxylates are soluble in the reaction solution.
  • Metal fluorides such as MgF 2 and CaF 2 and wetting agents such as water soluble alkyl-fluorides and fluorocarbons can also be added in very small quantities to these solutions (Tables III and IV) to improve corrosion protection and manufacturing ease.
  • alkyl fluoride wetting agents such as MSP-ST alkyl fluoride by M&T Harshaw, Cleveland, Ohio, and fluorocarbons FC99 or FC95 wetting agents by 3M Company, St. Paul, Minnesota, have been successfully used.
  • the presence of the fluorinated wetting agents, metal fluorides, or mixtures thereof raise the corrosion performance level of resultant coatings to such a degree that sealing of these conversion coatings in a secondary seal step is no longer required.
  • any water soluble fluorinated wetting agent capable of lowering liquid surface tension into the range of 0.03 N/m to 0.04 N/m (30 to 40 dynes per centimeter) at 20°C is usable.
  • Solutions operated as detailed below yield coatings that pass a 168 hours salt spray corrosion resistance criteria in accordance with Boeing Process Specification BAC 5719, "Chromated Conversion Coatings.”
  • the single step conversion coating has 'yielded in excess of 240 hours of salt spray resistance before showing any sign of corrosion pitting.
  • Cobalt acetate is the most preferred soluble cobalt-II salt.
  • Other water soluble cobalt salts such as Co(NO 3 ) 2 , CoSO 4 , CoCl 2, CoPO 4 , CoCO 3 , may be substituted for cobalt acetate, but are not preferred for the reasons illustrated in Table I.
  • These cobalt salts are preferably reacted with soluble metal carboxylates having from 1 to 5 carbon atoms, although metal salts of acetic acid are most preferred.
  • the carboxylate salts of Ca, Mg, and Na are preferred, with the Na carboxylate being most preferred, while Zn, Li, K, and Mn may also be used.
  • the limitations on using carboxylates other than the acetates is water solubility.
  • carboxylates that will work are for example sodium propionate.
  • the minimum solubility needed to produce an effective coating is about 0.01 moles of cobalt-II salt per liter of water at 20°C. (68°F).
  • the salts may be used up to their solubility limits.
  • fluorinated wetting agents may be added to the bath as discussed above. When these wetting agents are employed, a conversion coating is created that does not need to be subjected to a conventional sealing step in order to exhibit satisfactory corrosion resistance.
  • the concentration of dissolved cobalt-II salt used may be from about 0.01 mole per liter of final solution up to the solubility limit of the cobalt-II salt employed at 20°C (68°F).
  • the concentration of dissolved cobalt-II salt used may be from about 0 04 mole per liter of final solution up to 0.15 mole per liter of final solution.
  • the concentration of the cobalt-III hexcarboxylate coordination complex may be from about 0.01 mole per liter of final solution up to the solubility limit of the cobalt-III hexcarboxylate coordination complex employed.
  • the concentration of the cobalt-III hexcarboxylate coordination complex may be from about 0.04 mole per liter of final solution up to 0.15 mole per liter of final solution.
  • the concentration of dissolved metal carboxylate may be from about 0.03 to 2.5 moles per liter of final solution.
  • concentration of dissolved metal carboxylate used may be from about 0.05 mole per liter of final solution up to 0.2 mole per liter of final solution.
  • the concentration of the fluorinated wetting agents is preferably sufficient to hold solution surface tension between 3x10 -6 Nm to 4x10 -6 Nm (30 to 40 dynes) per centimeter at 20°C.
  • the metal fluorides, MgF 2 and CaF 2 may be present in a concentration from 0 to solubility limit. It is to be understood that the fluorinated wetting agents, metal fluorides, or mixtures thereof are not required, but are preferred. If the wetting agents and metal fluorides are not used, the conversion coating must be subjected to a sealing step to achieve high corrosion resistance. By using the wetting agents and fluorides, the sealing step can be eliminated, thus making the use of the present invention even more economical.
  • the pH of the bath may be from about 5.0 to 9.0 with 6.0 to 7.5 being preferred and 6.5 being most preferred.
  • the temperature of the bath may be from about 20°C to 71,1°C (68°F to 160°F). Above 71,1°C (160°F), gradual decomposition of the cobalt-III hexcarboxylate complex may occur. The optimum temperature is 60 ⁇ 2.2°C (140 ⁇ 5°F).
  • the immersion time may be from about 3 minutes to 60 minutes, more preferably from 5 to 30 minutes. When sodium acetate is employed, the immersion time can be reduced to 5 to 8 minutes. Use of these parameters will result in coating weights ranging for example from 215 mg/m 2 to 2583 mg/m 2 (20 to 240 mg/ft 2 ).
  • the cobalt conversion coating should be applied after all trimming and fabrication have been completed. Parts, where solution entrapment is possible, should not be subjected to immersion alkaline cleaning or immersion deoxidizing; manual cleaning and manual deoxidizing procedures should be used to obtain water break-free surfaces before applying cobalt conversion treatment.
  • a water break-free surface is a surface which maintains a continuous water film for a period of at least 30 seconds after having been sprayed or immersion rinsed in clean water at a temperature below 37.7°C (100°F).
  • Vapor degrease may be performed in accordance with Boeing Process Specification BAC 5408.
  • Emulsion clean in accordance with Boeing Process Specification BAC 5763, or solvent clean in accordance with Boeing Process Specification BAC 5750 if parts are greasy or oily. Parts with open faying surfaces or spot-welded joints where solution entrapment is possible should be immersed in cold water (or in hot and cold water) for 2 minutes after precleaning.
  • Alkaline clean and rinse may be performed in accordance with Boeing Process Specification BAC 5749, except for parts with open faying surfaces or spot welded joints, in which case, rinsing should be for at least 10 minutes using agitation with multiple immersions (a minimum of four times) followed by manual spray rinsing as required to prevent solution entrapment.
  • Deoxidize and rinse may be performed in accordance with Boeing Process Specification BAC 5765 except for parts where solution entrapment is possible, which parts may be rinsed using the method described above under "Alkaline Cleaning". Castings may be deoxidized by either of the following methods:
  • FIGURE 5 depicts the general behavior of cobalt conversion coatings with respect to corrosion performance vs. paint adhesion.
  • the intercept point of the corrosion and adhesion curve represents the bath parameters where the two divergent properties (corrosion and adhesion) are at optimum with respect to each other.
  • the pH be maintained between pH 6.0 and 7.5, although coatings have been produced between pH 5.0 and 9.0. Adjustments to the pH may be required after the solutions have been used for extended periods.
  • ESCA electron spectroscopy for chemical analysis (also known as XPS or X-ray photoelectron spectroscopy).) These analyses show that the cobalt conversion coating consists of a mixture of oxides, namely, aluminum oxide AL 2 O 3 as the largest volume percent, and cobalt oxides CoO, Co 2 O 3 , and Co 3 O 4 Al 2 O 3 .
  • large volume percent means that the volume of this oxide exceeds the volume of any other oxide which is present, but the term “largest volume percent” means that the volume of this oxide exceeds the volume of any other oxide which is present, but the term “largest volume present” does not necessarily imply that the volume of this oxide is more than 50 volume percent.
  • the data further shows that in the lower portion of the oxide coating (that is, next to the aluminum substrate), the largest volume percent is AL 2 O 3 .
  • the middle portion of the oxide coating is a mixture of CoO, Co 2 O 3 , Co 3 O 4 , and Al 2 O 3 .
  • the data shows that in the top portion of the oxide coating, the largest volume percent is a mixture of co 2 O 3 and Co 3 O 4 .
  • FIGS. 1 through 4 show a cobalt conversion coating 410 and 420 formed by a 15 minute immersion in a typical cobalt conversion coating solution.
  • the top surface of the cobalt conversion coating, as shown in FIGS. 1 through 4 bears a resemblance to a sponge, thus providing substantial surface area and porosity for good paint adhesion. Below the top surface, the coating becomes more dense and solid (nonporous).

Claims (33)

  1. Procédé pour la formation d'un revêtement de transformation au cobalt de film d'oxyde sur un substrat, dans lequel ledit substrat est de l'aluminium ou un alliage d'aluminium, ledit procédé comprenant les étapes consistant :
    (a) à fournir une solution de transformation au cobalt formant un film d'oxyde comprenant une solution réactionnelle aqueuse comprenant un complexe hexacoordiné de cobalt-III soluble, dans lequel ledit complexe hexacoordiné de cobalt-III est présent dans la forme de Mem[Co(R)6]n, où Me est un ou plusieurs éléments choisis parmi Na, Li, K, Ca, Zn, Mg et Mn et où m est égal à 2 ou à 3, n est égal à 1 ou à 2 et R est un carboxylate ayant de 1 à 5 atomes de C, la concentration dudit complexe hexacoordiné de cobalt-III étant comprise entre environ 0,01 mole par litre de ladite solution réactionnelle aqueuse et la limite de saturation dudit complexe hexacoordiné de cobalt-III; et
    (b) à mettre ledit substrat en contact avec ladite solution réactionnelle aqueuse sur une durée suffisante pour oxyder la surface dudit substrat, ledit revêtement de transformation au cobalt de film d'oxyde est par là formé, dans lequel ladite solution réactionnelle aqueuse présente un pH d'environ 5,0 à 9,0.
  2. Procédé selon la revendication 1, dans lequel on ajoute un agent mouillant de fluorure d'alkyle ou de fluorocarbone à ladite solution réactionnelle aqueuse dans la quantité exigée pour produire une tension superficielle du liquide de 0,03 N/m à 0,04 N/m (30 à 40 dynes par centimètre).
  3. Procédé selon les revendications 1 ou 2, dans lequel R est l'acétate.
  4. Procédé selon les revendications 1, 2 ou 3, dans lequel la concentration dudit complexe hexavalent de cobalt-III est comprise entre environ 0,04 mole par litre de solution et environ 0,15 mole par litre de solution.
  5. Procédé selon l'une quelconque des revendications 1-4, dans lequel ladite solution de transformation au cobalt est fournie en faisant réagir un sel de cobalt-II avec un carboxylate de métal ayant de 1 à 5 atomes de carbone.
  6. Procédé selon la revendication 5, dans lequel la concentration dudit sel de cobalt-II est comprise entre environ 0,04 mole par litre de solution finale et environ 0,15 moles par litre de solution finale et la concentration du carboxylate de métal est comprise entre environ 0,03 et 2,5 mole par litre de solution finale.
  7. Procédé selon les revendications 5 ou 6, dans lequel ledit sel de cobalt-II est un sel de cobalt-II qui présente une solubilité minimale d'environ 0,01 mole de sel de cobalt-II par litre d'eau à 20°C (68°F).
  8. Procédé selon l'une quelconque des revendications 5-7, dans lequel ledit sel de cobalt-II est l'acétate de cobalt.
  9. Procédé selon la revendication 5, dans lequel ladite solution de transformation au cobalt est préparée par une séquence de constitution du bain comprenant :
    (a) la dissolution dudit sel de carboxylate de métal, et
    (b) l'addition subséquente dudit sel de cobalt-II.
  10. Procédé selon la revendication 1, dans lequel ladite solution de transformation au cobalt présente un pH d'environ 5,0 à 9,0.
  11. Procédé selon la revendication 1, dans lequel ladite solution de transformation au cobalt présente une température d'environ 20°C à 71,1°C (68°F à 160°F).
  12. Procédé selon la revendication 1, dans lequel ledit substrat est mis en contact avec ladite solution de transformation au cobalt sur une durée d'environ 3 minutes à 60 minutes.
  13. Procédé selon la revendication 1, dans lequel on ajoute un agent mouillant fluoré à ladite solution de transformation au cobalt pour aider à la formation dudit revêtement de transformation au cobalt sur ledit substrat.
  14. Procédé selon la revendication 13, dans lequel ledit agent mouillant est choisi parmi un fluorure d'alkyle, des fluorocarbones, CaF2, MgF2 et des mélanges de ceux-ci.
  15. Procédé selon la revendication 13, dans lequel on ajoute ledit agent mouillant dans la quantité exigée pour produire une tension superficielle du liquide de 0,03 à 0,04 N/m (30 à 40 dynes par centimètre).
  16. Procédé selon la revendication 13, dans lequel on ajoute MgF2, CaF2 ou des mélanges de ceux-ci à ladite solution dans une quantité comprise entre 2 et 4 grammes par litre de solution finale.
  17. Procédé selon la revendication 1, dans lequel ledit substrat est de l'aluminium, un alliage d'aluminium, du magnésium, un alliage de magnésium, un substrat plaqué de Cd ou un substrat plaqué de Zn-Ni.
  18. Article produit par le procédé selon la revendication 1.
  19. Solution de revêtement de transformation chimique pour la production d'un revêtement de transformation au cobalt de film d'oxyde sur un substrat métallique, ladite solution comprenant une solution réactionnelle aqueuse comprenant un complexe hexacoordiné de cobalt-III soluble présent dans la forme de Mem[Co(R)6]n, où Me est un ou plusieurs éléments choisis parmi Na, Li, K, Ca, Zn, Mg et Mn et où m est égal à 2 ou à 3, n est égal à 1 ou à 2 et R est un carboxylate ayant de 1 à 5 atomes de C, la concentration dudit complexe hexacoordiné de cobalt-III étant comprise entre environ 0,01 mole par litre de solution et la limite de saturation dudit complexe hexacoordiné de cobalt-III, la solution réactionnelle aqueuse ayant un pH compris entre environ 5,0 et 9,0.
  20. Solution selon la revendication 19, dans laquelle R est un acétate.
  21. Solution selon la revendication 19, dans laquelle ledit complexe hexacoordiné de cobalt-III soluble est un complexe soluble de carboxylate de cobalt-III pouvant être obtenu en faisant réagir un sel de cobalt-II avec un sel de carboxylate de métal dans lequel le métal Me est défini dans la revendication 19 ayant de 1 à 5 atomes de C.
  22. Solution selon la revendication 21, dans laquelle la concentration dudit sel de cobalt-II est comprise entre environ 0,01 mole par litre de solution finale et la limite de saturation du sel de cobalt-II utilisé et la concentration dudit sel de carboxylate de métal est comprise entre environ 0,03 et 2,5 mole par litre de solution finale.
  23. Solution selon la revendication 21, dans laquelle ledit cobalt-II est un sel de cobalt-II qui présente une solubilité minimale d'environ 0,01 mole de sel de cobalt-II par litre d'eau à 20°C (68°F).
  24. Solution selon la revendication 21, dans laquelle ledit sel de cobalt-II est l'acétate de cobalt.
  25. Solution selon la revendication 21, dans laquelle ledit carboxylate de métal est un acétate de métal.
  26. Solution selon la revendication 21, dans laquelle ladite solution de transformation au cobalt est préparée par une séquence de constitution du bain comprenant :
    (a) la dissolution dudit carboxylate de métal; et
    (b) l'addition subséquente dudit sel de cobalt-II.
  27. Utilisation de la solution selon la revendication 19 pour la production d'un revêtement de transformation au cobalt de film d'oxyde sur un substrat métallique, dans laquelle ladite solution présente un pH d'environ 5,0 à 9,0.
  28. Utilisation de la solution selon la revendication 19 pour la production d'un revêtement de transformation au cobalt de film d'oxyde sur un substrat métallique, dans laquelle ladite solution présente une température d'environ 20°C à 71,7°C (68°F à environ 160°F).
  29. Utilisation de la solution selon la revendication 19 pour la production d'un revêtement de transformation au cobalt de film d'oxyde sur un substrat métallique, dans laquelle ledit substrat est de l'aluminium, un alliage d'aluminium, du magnésium, un alliage de magnésium, un substrat plaqué de Cd ou un substrat plaqué de Zn-Ni.
  30. Solution selon la revendication 19 comprenant un agent mouillant fluoré ajouté à ladite solution de transformation au cobalt pour aider à la formation dudit revêtement de transformation au cobalt sur ledit substrat.
  31. Solution selon la revendication 30, dans laquelle ledit agent mouillant est choisi parmi un fluorure d'alkyle, des fluorocarbones, CaF2, MgF2 et des mélanges de ceux-ci.
  32. Solution selon la revendication 30, dans laquelle ledit agent mouillant est ajouté dans la quantité exigée pour produire une tension superficielle du liquide de 0,03 à 0,04 N/m (30 à 40 dynes par cm).
  33. Solution selon la revendication 30, dans laquelle on ajoute MgF2, CaF2 ou des mélanges de ceux-ci à ladite solution dans une quantité comprise entre 2 et 4 g par litre de solution finale.
EP93914728A 1992-06-25 1993-06-23 Couche d'oxyde non chromate pour substrats en aluminium Expired - Lifetime EP0646187B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US903853 1992-06-25
US07/903,853 US5411606A (en) 1990-05-17 1992-06-25 Non-chromated oxide coating for aluminum substrates
CNB931017378A CN1138873C (zh) 1992-06-25 1993-01-18 在金属基体上形成钴转化膜层的方法，钴转化镀膜液及其用途
PCT/EP1993/001630 WO1994000619A1 (fr) 1992-06-25 1993-06-23 Couche d'oxyde non chromate pour substrats en aluminium

Publications (2)

Publication Number Publication Date
EP0646187A1 EP0646187A1 (fr) 1995-04-05
EP0646187B1 true EP0646187B1 (fr) 2001-01-10

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EP (1) EP0646187B1 (fr)
JP (1) JP3345010B2 (fr)
CN (2) CN1138873C (fr)
AT (1) ATE198631T1 (fr)
AU (1) AU687740B2 (fr)
BR (1) BR9306602A (fr)
CA (1) CA2138790C (fr)
DE (1) DE69329853T2 (fr)
DK (1) DK0646187T3 (fr)
ES (1) ES2152950T3 (fr)
GR (1) GR3035554T3 (fr)
MX (1) MX9303745A (fr)
NO (1) NO315522B1 (fr)
NZ (1) NZ253699A (fr)
RU (1) RU2135637C1 (fr)
SG (1) SG43169A1 (fr)
WO (1) WO1994000619A1 (fr)
ZA (1) ZA934544B (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5551994A (en) * 1990-05-17 1996-09-03 The Boeing Company Non-chromated oxide coating for aluminum substrates
ES2125231T3 (es) * 1991-07-19 1999-03-01 Boeing Co Revestimientos de oxido no cromado para sustratos de aluminio.
US5948178A (en) * 1995-01-13 1999-09-07 Henkel Corporation Composition and process for forming a solid adherent protective coating on metal surfaces
WO1996021753A1 (fr) * 1995-01-13 1996-07-18 Henkel Corporation Composition et procede destine a former un revetement protecteur adherent solide sur des surfaces en metal
AR001268A1 (es) * 1995-03-22 1997-10-08 Henkel Corp Procedimiento para formar un recubrimiento protector adherente solido sobre superficies metalicas.
FR2752851B1 (fr) * 1996-09-02 1998-11-13 Cfpi Ind Bain et procede de phosphatation de substrats metalliques, concentre pour la preparation de ce bain et substrats metalliques traites a l'aide de ces bain et procede
US5873953A (en) * 1996-12-26 1999-02-23 The Boeing Company Non-chromated oxide coating for aluminum substrates
US6315823B1 (en) 1998-05-15 2001-11-13 Henkel Corporation Lithium and vanadium containing sealing composition and process therewith
US7235142B2 (en) 2002-01-04 2007-06-26 University Of Dayton Non-toxic corrosion-protection rinses and seals based on cobalt
WO2003060019A1 (fr) 2002-01-04 2003-07-24 University Of Dayton Pigments anticorrosion non toxiques a base de cobalt
US7294211B2 (en) 2002-01-04 2007-11-13 University Of Dayton Non-toxic corrosion-protection conversion coats based on cobalt
FR2856079B1 (fr) * 2003-06-11 2006-07-14 Pechiney Rhenalu Procede de traitement de surface pour toles et bandes en alliage d'aluminium
CN1309864C (zh) * 2004-09-29 2007-04-11 广州擎天油漆化工实业有限公司 一种在铝及其合金表面上形成转化膜的工艺
CN100372972C (zh) * 2005-11-03 2008-03-05 复旦大学 在固体表面生长金属有机配合物的方法
CN103184445A (zh) * 2011-12-28 2013-07-03 上海航天精密机械研究所 一种铝合金表面化学氧化溶液组合物及工艺
CN103266315B (zh) * 2013-05-31 2015-05-13 海安县申菱电器制造有限公司 一种铝合金钴盐化学转化膜处理液的配制
CN103266314B (zh) * 2013-05-31 2015-05-13 海安县申菱电器制造有限公司 一种铝合金钴盐化学转化膜处理方法
CN104846309A (zh) * 2015-05-09 2015-08-19 安徽鼎恒再制造产业技术研究院有限公司 一种高强度Co3O4-SiC涂层材料及其制备方法
CN106868495B (zh) * 2017-01-23 2019-06-11 江苏理工学院 一种钴盐化学氧化废液的回收再利用方法
US20210268778A1 (en) * 2018-06-28 2021-09-02 Nelumbo Inc. Coincident Surface Modifications and Methods of Preparation Thereof

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US4381203A (en) * 1981-11-27 1983-04-26 Amchem Products, Inc. Coating solutions for zinc surfaces
US5298092A (en) * 1990-05-17 1994-03-29 The Boeing Company Non-chromated oxide coating for aluminum substrates
ATE154401T1 (de) * 1990-11-30 1997-06-15 Boeing Co Chromatfreier kobalt-konversionsüberzug
ES2125231T3 (es) * 1991-07-19 1999-03-01 Boeing Co Revestimientos de oxido no cromado para sustratos de aluminio.

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DE69329853D1 (de) 2001-02-15
GR3035554T3 (en) 2001-06-29
RU94046218A (ru) 1996-10-20
NO945026D0 (no) 1994-12-23
CA2138790C (fr) 2004-10-19
CN1080963A (zh) 1994-01-19
MX9303745A (es) 1994-02-28
ZA934544B (en) 1994-03-18
NO315522B1 (no) 2003-09-15
CN1195893C (zh) 2005-04-06
AU4500893A (en) 1994-01-24
JP3345010B2 (ja) 2002-11-18
RU2135637C1 (ru) 1999-08-27
ES2152950T3 (es) 2001-02-16
DK0646187T3 (da) 2001-04-30
NO945026L (no) 1995-02-24
EP0646187A1 (fr) 1995-04-05
WO1994000619A1 (fr) 1994-01-06
CA2138790A1 (fr) 1994-01-06
SG43169A1 (en) 1997-10-17
NZ253699A (en) 1997-05-26
CN1090338A (zh) 1994-08-03
DE69329853T2 (de) 2001-04-26
JPH07508311A (ja) 1995-09-14
CN1138873C (zh) 2004-02-18
ATE198631T1 (de) 2001-01-15
AU687740B2 (en) 1998-03-05
BR9306602A (pt) 1998-12-08

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