EP1409157B1 - Anticorrosive black coating on zinc alloy and method for making same - Google Patents

Anticorrosive black coating on zinc alloy and method for making same Download PDF

Info

Publication number
EP1409157B1
EP1409157B1 EP01958148A EP01958148A EP1409157B1 EP 1409157 B1 EP1409157 B1 EP 1409157B1 EP 01958148 A EP01958148 A EP 01958148A EP 01958148 A EP01958148 A EP 01958148A EP 1409157 B1 EP1409157 B1 EP 1409157B1
Authority
EP
European Patent Office
Prior art keywords
acid
solution
zinc alloy
process according
mol
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP01958148A
Other languages
German (de)
French (fr)
Other versions
EP1409157A2 (en
Inventor
Jean-Jacques Duprat
Lionel Thiery
Nicolas Pommier
Anne Charpentier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Coventya SAS
Original Assignee
Coventya SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Coventya SAS filed Critical Coventya SAS
Publication of EP1409157A2 publication Critical patent/EP1409157A2/en
Application granted granted Critical
Publication of EP1409157B1 publication Critical patent/EP1409157B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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
    • C23C22/48—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
    • C23C22/53—Treatment of zinc or alloys based thereon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/50—Multilayers
    • B05D7/51—One specific pretreatment, e.g. phosphatation, chromatation, in combination with one specific coating
    • 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
    • C23C22/10—Orthophosphates containing oxidants
    • 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
    • C23C22/46—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 oxalates
    • 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 a black anticorrosive layer formed of two layers on a zinc alloy and a process for preparing this anti-corrosive layer.
  • a zinc alloy for example Zn-Fe, Zn-Ni, Zn-Co, Zn-Mn.
  • the zinc alloy deposit can then be protected by a chromating layer. This can be achieved by treating the zinc alloy deposit with a solution containing Cr 6+ . But the use of solutions containing Cr 6+ is no longer desired for reasons of toxicity and protection of the environment.
  • US-A-5,415,702 proposes instead to treat a zinc / nickel or zinc / iron alloy with an acidic solution containing Cr 3+ ions and phosphate ions.
  • the surface thus coated with chromate can be contacted with an alkali metal silicate solution.
  • an organic coating for example a paint
  • This method has the following drawbacks: the protection against corrosion of a layer prepared by this method on a zinc / iron alloy is not sufficient compared to that of a layer prepared by this method on a zinc alloy / nickel. In addition, the protection against corrosion of a layer prepared by this method on a zinc / iron alloy is defective after heating for one hour beyond 150 ° C (thermal shock). Finally, it may occur due to the silicate coating after a while, white traces very undesired surface. In addition, the surface prepared by this process has an adhesion insufficient for subsequent painting.
  • the present invention aims to overcome the disadvantages of the state of the art, to further improve the protection of zinc alloys against corrosion, and to provide in particular an anticorrosive black layer on zinc alloys which exhibit heating for one hour up to 120 ° C or up to 150 ° C or in some cases beyond (thermal shock) and salt spray test according to DIN 50 021 corrosion resistance greater than 200 h.
  • the invention also aims to give the anticorrosive layer a uniform, non-alterable, black appearance over time.
  • the process according to the invention is defined in claim 1. It consists in treating the zinc alloy in a first step with an aqueous acidic solution of Cr 3+ , containing a complexing agent or several complexing agents, and treating the zinc alloy thus passivated in a second step of the process by an aqueous solution containing an organic polymer, an anticorrosive metal oxide and optionally a black pigment.
  • the anticorrosion coating made on a zinc alloy according to the invention consists of a superposition of two individual layers, prepared according to a process according to the invention, the first layer having a layer weight (expressed as Cr) of 1 to 4 mg / dm 2 .
  • the process described according to the invention consists of two steps.
  • the deposition of zinc alloy is treated with an acidic aqueous solution of Cr 3+ free Cr 6+ containing one or more complexing agents.
  • the deposit is thus passivated.
  • the treatment time is from 20 to 400 seconds.
  • a preferred treatment time is between 60 and 240 seconds.
  • the passivated zinc alloy, rinsed and drained is treated with an aqueous suspension containing organic polymers, anticorrosive metal oxides and optionally black pigments.
  • the treatment time is from 5 to 120 seconds.
  • the zinc alloy thus treated can be dried in hot air (for example between 50 and 75 ° C, preferably at 70 ° C).
  • the pH of the acid solution of Cr 3+ will be between 1 and 4, preferably between 1 and 3.
  • the pH adjustment is preferably carried out using mineral acids such as HNO 3 , H 2 SO 4 , HCl or H 3 PO 4 .
  • the treatment of the zinc alloy with the passivation solution and by the suspension can be carried out in different ways, for example by immersion, spraying, brush or roller.
  • the immersion application will be used preferentially.
  • the temperature of the Cr 3+ solution used in the first step of the process is between 20 and 80 ° C, preferably between 25 and 60 ° C; the temperature of the aqueous suspension used in the second stage of the process is between 15 and 35 ° C, preferably between 20 and 30 ° C.
  • Trivalent chromium can be introduced into the solution in the form of trivalent chromium salts, such as for example CrCl 3 , 6H 2 O, Cr (NO 3 ) 3 , 9H 2 O, chromium (III) acetate or in the form of trivalent chromium sulphate ("pure" chromium sulphate or chromium sulphate and other cations, for example KCr (SO 4 ) 2 12H 2 O).
  • a Cr 3+ solution can be prepared from a solution of Cr 6+ with addition of a mineral acid in the presence of a reducing agent such as, for example, formaldehyde or sodium hydrogen sulfite.
  • the lower limit of the chromium content of the solution (expressed as Cr 3+ ) is 1 g / l (which corresponds to 0.02 mol / l), preferably 5 g per liter (corresponding to 0 1 mol / l); the upper limit of the chromium (III) content of the solution is 30 g / l (corresponding to 0.58 mol / l), but preferably 20 g / l (corresponding to 0.38 mol / l).
  • the solution contains one or more complexing agents such as phosphates, hypophosphites, acid salts organic compounds (eg citric acid, oxalic acid, tartaric acid, malonic acid, maleic acid, formic acid, acetic acid, lactic acid, aminoacetic acid, iminodiacetic acid) or urea.
  • complexing agents such as citric acid, oxalic acid, tartaric acid, malonic acid, maleic acid, formic acid, acetic acid, lactic acid, aminoacetic acid, iminodiacetic acid
  • the phosphates will be used preferentially because they particularly favor the formation of a dark conversion layer. Phosphates act as a "proton reservoir", these protons allow to activate and maintain the passivation process of the zinc alloy deposit.
  • the phosphates will be incorporated for example in the form of Na 3 PO 4 , Na 2 HPO 4 , NaH 2 PO 4 or in the form of phosphoric acid. Phosphates may be present for a minimum concentration in the solution (expressed as PO 4 3- ) of 10 g / l (corresponding to 0.01 mol / l), preferably 15 g / l (which corresponds to 0.15 mol / l).
  • the upper limit of the phosphate concentration in the solution is preferably 44 g / l (corresponding to 0.42 mol / l), in particular preferably 25 g / l (corresponding to 0.26 mol / l). l).
  • Hypophosphite may be added (for example in the form of alkali metal hypophosphite such as NaH 2 PO 2 or in the form of hypophosphorous acid), alone or preferably with phosphates.
  • An advantageous effect of hypophosphite is that it delays the precipitation of chromium hydroxide in the solution on the surface of the zinc alloy to a pH of 4.5. Without the addition of hypophosphite, the chromium hydroxide precipitates at a pH of the solution of 3.0.
  • the minimum concentration of hypophosphite (expressed in H 2 PO 2 - ) is 0.08 mol / l, and preferably 0.23 mol / l.
  • the upper limit of the concentration of hypophosphite is 0.65 mol / l and preferably 0.5 mol / l and more preferably 0.45 mol / l.
  • the other complexing agents mentioned can be incorporated at a level of from 0.025 mol / l to 0.6 mol / l, with a particular preference for the interval between 0.06 and 0.2 mol / l. It is preferable to use them together with phosphates and / or hipophosphite.
  • Corrosion protection and blackness uniformity can be further improved by the addition of iron, molybdenum, cobalt and / or nickel ions to the Cr 3+ solution.
  • the amounts to be added may for example be between 0.001 mol / l and 0.1 mol / l.
  • the protection against corrosion and the adhesion of the topcoat can be improved by incorporating into the passivation solution silicon dioxide in the form of colloidal particles such as for example the Ludox dispersion AM30 marketed by the company Du Bridge.
  • the amount incorporated may be between 0.07 mol / l and 1.3 mol / l.
  • the passivation layer or stratum 1 has a thickness of between 0.5 and 5 ⁇ and preferably between 0.5 ⁇ and 1.5 ⁇
  • the aqueous suspension used in the second stage of the process contains organic polymers, anticorrosive metal oxides and possibly black pigments.
  • the organic polymers used are of the copolymer type acrylic, methacrylic or vinyl resins. They are polymers of the ester of acrylic acid or methacrylic acid and may have as their alcohol component an unsubstituted or substituted alkyl group with functional groups, for example a methyl, ethyl, propyl or isopropyl group, n-butyl, isobutyl, tert-butyl, pentyl and hexyl and their isomers and higher homologues, 2-ethylhexyl, phenoxyethyl, hydroxyethyl, 2-hydroxypropyl, caprolactone-hydroxyethyl or dimethylaminoethyl.
  • Commercially available acrylate copolymers are, for example, Lugalvan DC from BASF or Carboset 560 from BF Goodrich.
  • polyethylene waxes in the form of an emulsion, for example, Polygene PE from BASF or Luciwax EN 41 from Morton.
  • the waxes advantageously increase the wear resistance of the surfaces and make it possible to obtain, depending on the wax used, advantageous sliding properties, such as a coefficient of low friction of between 0.08 and 0.18.
  • suitable waxes in the suspension makes it possible to obtain constant coefficient of friction values at ⁇ 0.03.
  • the amount of organic polymers added (expressed as dry matter, respectively) is in total from 5 to 150 g / l, preferably from 10 to 100 g / l.
  • a combination of 5 to 90 g / l of acrylate or methacrylate copolymer and 1 to 60 g / l of polyethylene wax was found to be very favorable.
  • anticorrosive metal oxides use is made of silicon dioxide, titanium dioxide, zirconium dioxide, and / or rare earth oxides such as cerium oxide or La 2 O 3 or Y 2 O 3 or Pr 6 O 11 . These metal oxides are preferably used in the form of an aqueous suspension of nanoparticles.
  • concentration of the metal oxides (relative to the solid material) in the aqueous suspension used in the second stage of the process is preferably from 20 to 60 g / l, in particular with a preference for the interval between 30 and 45 g / l.
  • the metal oxides are fixed by the organic polymers.
  • the introduction of the mineral substances in the anticorrosive layer in this form has, compared to the known treatment with solutions of these substances (for example sodium silicate solutions) the advantage of improving the protection against corrosion and maintain the uniform black color of the anticorrosive layer over time.
  • the uniform black appearance of the anticorrosive layer can be further enhanced by addition of carbon black pigments (for example Derussol P130 from Degussa) or other pigments but such as the Black Sanodal marketed by Clariant in the suspension aqueous solution used during the second stage of the process.
  • carbon black pigments for example Derussol P130 from Degussa
  • the concentration of carbon black pigments in the aqueous suspension is between 5 and 20 g / l.
  • the friction layer or second layer deposited in the second stage has a thickness of 0.5 to 5 ⁇ and preferably 0.5 to 2.5 ⁇ .
  • the anticorrosive layer thus has a thickness in general of between 1 ⁇ and 5 ⁇ and preferably between 1 ⁇ and 4 ⁇ .
  • the anticorrosive layer produced in two stages according to the process according to the invention which has just been described on galvanized metal surfaces has a layer weight in the first layer (expressed as Cr) of 0.5 to 4 mg / dm 2 .
  • the formed chromium layer (first layer) is dissolved on the galvanized metal surface after the first process step (passivation) with 10% hydrochloric acid and the chromium content is determined by means of a atomic absorption spectroscopy.
  • the second layer of the anticorrosive layer consists of anticorrosive metal oxides, black pigments and, if appropriate, other additives incorporated into organic polymers.
  • An advantage of this anticorrosive layer according to the invention lies in the absence of Cr 6+ and in a corrosion resistance after heating for one hour at 120 ° C. or at 150 ° C., and a salt spray resistance according to the invention.
  • the aqueous suspension making it possible to produce the second layer consists of 90 g / l of a colloidal dispersion containing 44% of silicon dioxide particles in water (Ludox AS 40 from Du Pont), of 50 g / l of a 27% acrylic copolymer (Carboset 560 from the company BF Goodrich) and 70 g / l of an ethylenic grafted acrylic copolymer (Lugalvan DC from BASF).
  • 50 g / l of a 20% carbon black dispersion (Derussol P 130 from Degussa) is introduced as a black pigment into the aqueous solution.
  • Standard 100 mm ⁇ 70 mm steel plates are coated in a conventional zinc / iron alloy (0.5% Fe), activated in a 5 ml / l nitric acid solution. then, after rinsing, they are immersed for approximately 180 seconds in the Cr 3+ solution (temperature of the solution 25 ° C.), rinsed, drained in a stream of air (room temperature), quenched during 30 seconds in the aqueous suspension and dried for about 15 minutes in a hot air stream (70 ° C). The appearance of the plates is then black uniform.
  • the chromium content of the anticorrosion layer is (before treatment with the aqueous suspension) 2 mg / dm 2 .
  • the steel plates thus treated are heated for 1 hour at 150 ° C. (thermal shock) and then subjected to a salt spray test according to DIN 50 021. An appearance of white rust is observed after 300 hours.
  • chromium nitrate 11.5% chromium content
  • 20 g of 85% phosphoric acid, 0.3 g of 69% nitric acid and 75 g of colloidal silica dispersion type Ludox AM 30 are added thereto and the volume is adjusted to 1 liter with water. water. The pH is adjusted to between 1.5 and 1.6 with 50% NaOH solution.
  • Standard steel plates are conventionally coated 100 mm x 70 mm of a zinc / nickel alloy (Ni 12 to 15%), soaked for about 90 seconds in the solution of Cr 3+ (temperature of the solution 25 ° C), rinsed, they are drained in a stream of air (room temperature), quenched for about 30 seconds in the aqueous suspension (of Example 1) and dried for about 10 minutes in a stream of hot air (70 ° C.). VS).
  • the steel plates have a uniform black appearance.
  • the chromium content of the anticorrosion layer is (before treatment with the aqueous suspension)> 2 mg / dm 2 .
  • the steel plates thus treated are heated for 1 hour at 120 ° C (thermal shock) and then subjected to a salt spray test according to DIN 50 021.
  • the parts do not exhibit white rust after 240 hours and no red rust after 800 hours.
  • the Cr 3+ solution consists of 55 g / l of Chromitan (trade name) (chromium (III) sulphate salt), which corresponds to a Cr 3+ content of the 9.35 solution.
  • g / l 25.5 g / l H 3 PO 4 , 30 g / l sodium hypophosphite, 20 g / l citric acid and 0.9 g / l HNO 3
  • the pH of the solution is adjusted to 2.5 with 20% NaOH solution.
  • the aqueous suspension making it possible to produce the second layer consists of 90 g / l of a colloidal dispersion containing 44% of silicon dioxide particles in water (Ludox AS40 from Du Pont), 50 g / l of 27% acrylic copolymer (Carboset 560 from the company BF Goolrich) and 70 g / l of an ethylenic grafted acrylic copolymer (Cugalvan DC from BASF)
  • Standard 100 mm x 70 mm steel plates of a zinc / iron alloy (0.5% Fe) were conventionally coated, cleaned and immersed for about 240 seconds in Cr 3+ (temperature of the solution 25 ° C), rinsed, drained in a stream of air (room temperature), soaked for about 30 seconds in the aqueous suspension described above and dried for about 15 minutes in a stream of hot air (70 ° C). The appearance of the plates is then black uniform.
  • the chromium content of the anticorrosion layer is (before treatment with the aqueous suspension) greater than 2 mg / dm 2 .
  • the solution is filtered through a filter paper having a pore diameter of 100 ⁇ m and is heated for 2 hours at 60 ° C.
  • the pH is adjusted to between 2.3 and 2.5 with 50% NaOH solution.
  • To this solution is added 1 g of cobalt sulfate CoSO 4 , 7H 2 O.
  • Standard steel plates of 100 mm x 70 mm of a zinc / iron alloy (0.5% Fe) are conventionally coated, activated in a 5 ml / l nitric acid solution, soaking them for about 60 seconds in the Cr 3+ solution (solution temperature 25 ° C), rinsing them and draining them in a stream of air (room temperature). The appearance of the plates is then black uniform.
  • the chromium content of the anticorrosion layer is greater than 2 mg / dm 2 .
  • the steel plates thus treated are immersed for about 30 seconds in the aqueous suspension (Example 1) and dried for about 15 minutes in a stream of hot air (70 ° C.) and heated for 24 hours at 120 ° C. ° C (thermal shock) and then subjected to a salt spray test according to DIN 50021. After 300 h, no white rust was observed.
  • KCr (SO 4 ) 2 , 12H 2 O 100 g of KCr (SO 4 ) 2 , 12H 2 O are dissolved in 200 ml of water. 20 g of NaOH are dissolved in about 100 ml and added thereto. It is heated at 80 ° C. for 1 hour. After cooling to about 25 ° C., 20 g of sodium hypophosphite, 20 g of citric acid, 15 g of 85% phosphoric acid, 0.6 g of 69% nitric acid and 100 g of typical silica dispersion Ludox AM30, the solution is then added to 1 1 with water. The pH of the solution is 2.5.
  • Standard steel plates of 100 mm x 70 mm of a zinc / iron alloy (0.5% Fe) are conventionally coated, activated in a 5 ml / l nitric acid solution, soaking them for 180 seconds in the Cr 3+ solution (solution temperature 25 ° C), rinsing them and draining them in a stream of air (room temperature).
  • the steel plates have a uniform black appearance.
  • the chromium content of the anticorrosive layer is between 2 and 4 mg / dm 2 .
  • the steel plates are quenched for about 30 seconds in the aqueous suspension (of Example 1) and dried for about 15 minutes in a stream of hot air (70 ° C.) and heated for 24 hours. 120 ° C (thermal shock) and then subjected to a salt spray test according to DIN 50 021. After 200 h, no white rust was observed.
  • Standard 100 mm x 70 mm steel plates are conventionally coated with a 12 ⁇ m thick zinc / nickel (Ni 15%) alloy, soaked in the Cr 3+ solution for 75 seconds. (temperature of the solution 25 ° C), rinsed and drained in a stream of air (room temperature).
  • the steel plates have a uniform black appearance.
  • the chromium content of the anticorrosive layer is 2 mg / dm 2 .
  • the steel plates are quenched for about 30 seconds in the aqueous suspension (of Example 3) and dried for about 15 minutes in a stream of hot air (70 ° C).
  • the plates are then heated for one hour at 120 ° C. (thermal shock), and then subjected to a salt spray test according to DIN 50 021. After 200 hours, no white rust is observed, and after 800 h, no red rust is observed.

Abstract

The invention concerns a method for depositing an anticorrosive black coating on a zinc alloy which consists in treating the zinc alloy in a first step with an aqueous acid solution of Cr3+ containing one or several complexing agents and in treating the resulting passivated zinc alloy in a second step with an aqueous suspension containing organic polymers and anticorrosive metal oxides and black pigments. The invention also concerns a black anticorrosive coating with two layers on a zinc alloy, the first layer of the anticorrosive coating having a weight (in Cr) of 1 to 4 mg/dm2.

Description

L'invention concerne une couche anticorrosive noire formée de deux strates sur un alliage de zinc et un procédé de préparation de cette couche anti-corrosive.The invention relates to a black anticorrosive layer formed of two layers on a zinc alloy and a process for preparing this anti-corrosive layer.

Pour les protéger de la corrosion, on revêt des surfaces métalliques, par exemple des surfaces en acier, d'un alliage de zinc (par exemple Zn-Fe, Zn-Ni, Zn-Co, Zn-Mn). Le dépôt de zinc allié peut ensuite être protégé par une couche de chromatation. Celle-ci peut être obtenue en traitant le dépôt de zinc allié par une solution contenant du Cr6+. Mais l'utilisation de solutions contenant du Cr6+ n'est plus souhaitée pour des raisons de toxicité et de protection de l'environnement. Le brevet US-A 5 415 702 propose en substitution de traiter un alliage de zinc/nickel ou zinc/fer par une solution acide renfermant des ions Cr3+ et des ions phosphates. La surface ainsi revêtue de chromate peut être mise en contact avec une solution de silicate de métal alcalin. Finalement dans un autre stade opératoire, on peut déposer sur la couche de silicate ainsi obtenue, un revêtement organique (par exemple une peinture).To protect them from corrosion, metallic surfaces, for example steel surfaces, are coated with a zinc alloy (for example Zn-Fe, Zn-Ni, Zn-Co, Zn-Mn). The zinc alloy deposit can then be protected by a chromating layer. This can be achieved by treating the zinc alloy deposit with a solution containing Cr 6+ . But the use of solutions containing Cr 6+ is no longer desired for reasons of toxicity and protection of the environment. US-A-5,415,702 proposes instead to treat a zinc / nickel or zinc / iron alloy with an acidic solution containing Cr 3+ ions and phosphate ions. The surface thus coated with chromate can be contacted with an alkali metal silicate solution. Finally, in another stage of operation, an organic coating (for example a paint) may be deposited on the silicate layer thus obtained.

Ce procédé présente les inconvénients suivants : la protection face à la corrosion d'une couche préparée par ce procédé sur un alliage de zinc/fer n'est pas suffisante par rapport à celle d'une couche préparée par ce procédé sur un alliage zinc/nickel. En outre, la protection face à la corrosion d'une couche préparée par ce procédé sur un alliage de zinc/fer est défectueuse après un chauffage d'une heure au-delà de 150°C (choc thermique). Enfin, il peut se produire en raison du revêtement à base de silicate après un certain temps, des traces blanches très peu souhaitées en surface. De plus, la surface préparée par ce procédé présente une adhérence insuffisante pour une peinture ultérieure.This method has the following drawbacks: the protection against corrosion of a layer prepared by this method on a zinc / iron alloy is not sufficient compared to that of a layer prepared by this method on a zinc alloy / nickel. In addition, the protection against corrosion of a layer prepared by this method on a zinc / iron alloy is defective after heating for one hour beyond 150 ° C (thermal shock). Finally, it may occur due to the silicate coating after a while, white traces very undesired surface. In addition, the surface prepared by this process has an adhesion insufficient for subsequent painting.

La présente invention vise à surmonter les inconvénients de l'état de la technique, à améliorer encore la protection des alliages de zinc vis-à-vis de la corrosion, et à procurer notamment une couche noire anticorrosive sur des alliages de zinc qui présentent après un chauffage d'une heure jusqu'à 120°C ou jusqu'à 150°C ou dans certains cas au-delà (choc thermique) et un essai au brouillard salin suivant la norme DIN 50 021 une résistance à la corrosion supérieure à 200 h. L'invention vise en outre à donner à la couche anticorrosive un aspect noir uniforme non altérable au cours du temps.The present invention aims to overcome the disadvantages of the state of the art, to further improve the protection of zinc alloys against corrosion, and to provide in particular an anticorrosive black layer on zinc alloys which exhibit heating for one hour up to 120 ° C or up to 150 ° C or in some cases beyond (thermal shock) and salt spray test according to DIN 50 021 corrosion resistance greater than 200 h. The invention also aims to give the anticorrosive layer a uniform, non-alterable, black appearance over time.

Le procédé suivant l'invention est défini dans la revendication 1. Il consiste à traiter l'alliage de zinc dans une première étape par une solution aqueuse acide de Cr3+, contenant un agent complexant ou plusieurs agents complexants, et à traiter l'alliage de zinc ainsi passivé dans une deuxième étape du procédé par une solution aqueuse contenant un polymère organique, un oxyde métallique anticorrosif et éventuellement un pigment noir. Le revêtement anticorrosion réalisé sur un alliage de zinc suivant l'invention est constitué d'une superposition de deux couches individuelles, préparées selon un procédé suivant l'invention, la première couche ayant un poids de couche (exprimé en Cr) de 1 à 4 mg/dm2.The process according to the invention is defined in claim 1. It consists in treating the zinc alloy in a first step with an aqueous acidic solution of Cr 3+ , containing a complexing agent or several complexing agents, and treating the zinc alloy thus passivated in a second step of the process by an aqueous solution containing an organic polymer, an anticorrosive metal oxide and optionally a black pigment. The anticorrosion coating made on a zinc alloy according to the invention consists of a superposition of two individual layers, prepared according to a process according to the invention, the first layer having a layer weight (expressed as Cr) of 1 to 4 mg / dm 2 .

Le procédé décrit suivant l'invention est constitué de deux étapes. Dans la première étape, le dépôt de zinc allié est traité par une solution aqueuse acide de Cr3+ exempte de Cr6+ renfermant un ou plusieurs agents complexants. Le dépôt est ainsi passivé. La durée de traitement va de 20 à 400 secondes. Une durée de traitement préférée est comprise entre 60 et 240 secondes. Dans une deuxième étape du procédé, l'alliage de zinc passivé, rincé et égoutté, est traité par une suspension aqueuse renfermant des polymères organiques, des oxydes métalliques anticorrosifs et éventuellement des pigments noirs. La durée de traitement va de 5 à 120 secondes. Finalement, on peut sécher l'alliage de zinc ainsi traité dans de l'air chaud (par exemple entre 50 et 75°C, de préférence à 70°C).The process described according to the invention consists of two steps. In the first step, the deposition of zinc alloy is treated with an acidic aqueous solution of Cr 3+ free Cr 6+ containing one or more complexing agents. The deposit is thus passivated. The treatment time is from 20 to 400 seconds. A preferred treatment time is between 60 and 240 seconds. In a second step of the process, the passivated zinc alloy, rinsed and drained, is treated with an aqueous suspension containing organic polymers, anticorrosive metal oxides and optionally black pigments. The treatment time is from 5 to 120 seconds. Finally, the zinc alloy thus treated can be dried in hot air (for example between 50 and 75 ° C, preferably at 70 ° C).

Le pH de la solution acide de Cr3+ sera compris entre 1 et 4, de préférence entre 1 et 3. Le réglage du pH s'effectue de préférence à l'aide d'acides minéraux comme HNO3, H2SO4, HCl ou H3PO4.The pH of the acid solution of Cr 3+ will be between 1 and 4, preferably between 1 and 3. The pH adjustment is preferably carried out using mineral acids such as HNO 3 , H 2 SO 4 , HCl or H 3 PO 4 .

Le traitement de l'alliage de zinc par la solution de passivation et par la suspension peut être effectué de différente manière, par exemple par immersion, par projection, à la brosse ou au rouleau. L'application par immersion sera utilisée préférentiellement. La température de la solution de Cr3+ utilisée dans la première étape du procédé est comprise entre 20 et 80°C, de préférence entre 25 et 60°C ; la température de la suspension aqueuse utilisée dans la deuxième étape du procédé est comprise entre 15 et 35°C, de préférence entre 20 et 30°C.The treatment of the zinc alloy with the passivation solution and by the suspension can be carried out in different ways, for example by immersion, spraying, brush or roller. The immersion application will be used preferentially. The temperature of the Cr 3+ solution used in the first step of the process is between 20 and 80 ° C, preferably between 25 and 60 ° C; the temperature of the aqueous suspension used in the second stage of the process is between 15 and 35 ° C, preferably between 20 and 30 ° C.

Le chrome trivalent peut être introduit dans la solution sous la forme de sels de chrome trivalents, comme par exemple CrCl3, 6H2O, Cr(NO3)3, 9H2O, l'acétate de chrome (III) ou sous forme de sulfate de chrome trivalent (sulfate de chrome "pur" ou sulfate de chrome et d'autres cations comme par exemple KCr(SO4)2 12H2O). Suivant une autre possibilité, on peut préparer une solution de Cr3+ à partir d'une solution de Cr6+ avec addition d'un acide minéral en présence d'un agent réducteur comme par exemple le formaldéhyde ou l'hydrogénosulfite de sodium. La limite inférieure de la teneur en chrome de la solution (exprimée en Cr3+) est de 1 g/l (ce qui correspond à 0,02 mol/l), de préférence de 5 g par litre (ce qui correspond à 0,1 mol/l) ; la limite supérieure de la teneur en chrome (III) de la solution est de 30 g/l (ce qui correspond à 0,58 mol/l), mais de préférence de 20 g/l (ce qui correspond à 0,38 mol/l).Trivalent chromium can be introduced into the solution in the form of trivalent chromium salts, such as for example CrCl 3 , 6H 2 O, Cr (NO 3 ) 3 , 9H 2 O, chromium (III) acetate or in the form of trivalent chromium sulphate ("pure" chromium sulphate or chromium sulphate and other cations, for example KCr (SO 4 ) 2 12H 2 O). Alternatively, a Cr 3+ solution can be prepared from a solution of Cr 6+ with addition of a mineral acid in the presence of a reducing agent such as, for example, formaldehyde or sodium hydrogen sulfite. The lower limit of the chromium content of the solution (expressed as Cr 3+ ) is 1 g / l (which corresponds to 0.02 mol / l), preferably 5 g per liter (corresponding to 0 1 mol / l); the upper limit of the chromium (III) content of the solution is 30 g / l (corresponding to 0.58 mol / l), but preferably 20 g / l (corresponding to 0.38 mol / l).

Pour complexer les ions Cr3+ et réguler ainsi la précipitation de l'hydroxyde de chrome III à la surface de la pièce pendant l'opération de conversion, la solution contient un ou plusieurs agents complexants tels que phosphates, hypophosphites, sels d'acides organiques (par exemple l'acide citrique, l'acide oxalique, l'acide tartrique, l'acide malonique, l'acide maléique, l'acide formique, l'acide acétique, l'acide lactique, l'acide aminoacétique, l'acide iminodiacétique) ou de l'urée.To complex the Cr 3+ ions and thus regulate the precipitation of the chromium hydroxide III at the surface of the part during the conversion operation, the solution contains one or more complexing agents such as phosphates, hypophosphites, acid salts organic compounds (eg citric acid, oxalic acid, tartaric acid, malonic acid, maleic acid, formic acid, acetic acid, lactic acid, aminoacetic acid, iminodiacetic acid) or urea.

Les phosphates seront utilisés de façon préférentielle parce qu'ils favorisent particulièrement la formation d'une couche de conversion foncée. Les phosphates agissent en tant que "réservoir de protons", ces protons permettent d'activer et de maintenir le processus de passivation du dépôt de zinc allié. Les phosphates seront incorporés par exemple sous la forme de Na3PO4, Na2HPO4, NaH2PO4 ou sous la forme d'acide phosphorique. Les phosphates peuvent être présents pour une concentration minimale dans la solution (exprimée en PO4 3-) de 10 g/l (ce qui correspond à 0,01 mol/l), de préférence de 15 g/l (ce qui correspond à 0,15 mol/l). La limite supérieure de la concentration en phosphate dans la solution est de préférence de 44 g/l (ce qui correspond à 0,42 mol/l), notamment de préférence de 25 g/l (ce qui correspond à 0,26 mol/l).The phosphates will be used preferentially because they particularly favor the formation of a dark conversion layer. Phosphates act as a "proton reservoir", these protons allow to activate and maintain the passivation process of the zinc alloy deposit. The phosphates will be incorporated for example in the form of Na 3 PO 4 , Na 2 HPO 4 , NaH 2 PO 4 or in the form of phosphoric acid. Phosphates may be present for a minimum concentration in the solution (expressed as PO 4 3- ) of 10 g / l (corresponding to 0.01 mol / l), preferably 15 g / l (which corresponds to 0.15 mol / l). The upper limit of the phosphate concentration in the solution is preferably 44 g / l (corresponding to 0.42 mol / l), in particular preferably 25 g / l (corresponding to 0.26 mol / l). l).

De l'hypophosphite peut être ajouté (par exemple sous forme d'hypophosphite de métal alcalin comme NaH2PO2 ou sous forme d'acide hypophosphoreux), seul ou de préférence avec des phosphates. Un effet avantageux de l'hypophosphite réside dans le fait qu'il retarde la précipitation de l'hydroxyde de chrome dans la solution à la surface de l'alliage de zinc jusqu'à un pH de 4,5. Sans addition d'hypophosphite, l'hydroxyde de chrome précipite dès un pH de la solution de 3,0. La concentration minimale d'hypophosphite (exprimée en H2PO2 -) est de 0,08 mol/l, et préférentiellement de 0,23 mol/l. La limite supérieure de la concentration en hypophosphite est de 0,65 mol/l et préférentiellement 0,5 mol/l et plus préférentiellement 0,45 mol/l.Hypophosphite may be added (for example in the form of alkali metal hypophosphite such as NaH 2 PO 2 or in the form of hypophosphorous acid), alone or preferably with phosphates. An advantageous effect of hypophosphite is that it delays the precipitation of chromium hydroxide in the solution on the surface of the zinc alloy to a pH of 4.5. Without the addition of hypophosphite, the chromium hydroxide precipitates at a pH of the solution of 3.0. The minimum concentration of hypophosphite (expressed in H 2 PO 2 - ) is 0.08 mol / l, and preferably 0.23 mol / l. The upper limit of the concentration of hypophosphite is 0.65 mol / l and preferably 0.5 mol / l and more preferably 0.45 mol / l.

Les autres agents complexants mentionnés peuvent être incorporés à hauteur de 0,025 mol/l à 0,6 mol/l avec une préférence notamment pour l'intervalle comprise entre 0,06 et 0,2 mol/l. Il est préférable de les utiliser en même temps que des phosphates et/ou de l'hipophosphite.The other complexing agents mentioned can be incorporated at a level of from 0.025 mol / l to 0.6 mol / l, with a particular preference for the interval between 0.06 and 0.2 mol / l. It is preferable to use them together with phosphates and / or hipophosphite.

On peut encore améliorer la protection vis-à-vis de la corrosion ainsi que l'uniformité de la teinte noire par l'addition d'ions des éléments fer, molybdène, cobalt et/ou nickel à la solution de Cr3+. Les quantités à ajouter peuvent être par exemple comprises entre 0,001 mol/l et 0,1 mol/l.Corrosion protection and blackness uniformity can be further improved by the addition of iron, molybdenum, cobalt and / or nickel ions to the Cr 3+ solution. The amounts to be added may for example be between 0.001 mol / l and 0.1 mol / l.

La protection vis-à-vis de la corrosion et l'adhérence de la couche de finition peuvent être améliorées en incorporant dans la solution de passivation du dioxyde de silicium sous forme de particules colloïdales comme par exemple la dispersion Ludox AM30 commercialisée par la société Du Pont. La quantité incorporée pourra être comprise entre 0,07 mol/l et 1,3 mol/l.The protection against corrosion and the adhesion of the topcoat can be improved by incorporating into the passivation solution silicon dioxide in the form of colloidal particles such as for example the Ludox dispersion AM30 marketed by the company Du Bridge. The amount incorporated may be between 0.07 mol / l and 1.3 mol / l.

La couche de passivation ou 1ère strate a une épaisseur comprise entre 0,5 et 5 µ et de préférence, entre 0,5 µ et 1,5 µThe passivation layer or stratum 1 has a thickness of between 0.5 and 5 μ and preferably between 0.5 μ and 1.5 μ

La suspension aqueuse utilisée dans la deuxième étape du procédé renferme des polymères organiques, des oxydes métalliques anticorrosifs et éventuellement des pigments noirs.The aqueous suspension used in the second stage of the process contains organic polymers, anticorrosive metal oxides and possibly black pigments.

Les polymères organiques utilisés sont du type copolymère acrylique, méthacrylique ou résines vinyliques. Ce sont des polymères de l'ester de l'acide acrylique ou de l'acide méthacrylique et ils peuvent avoir comme constituant alcoolique un groupe alcoyle non substitué ou substitué par des groupes fonctionnels, par exemple un groupe méthyle, éthyle, propyle, isopropyle, n-butyle, isobutyle, tert-butyle, pentyle et hexyle et leurs isomères et homologues supérieurs, 2-éthylhexyle, phénoxyéthyle, hydroxyéthyle, 2-hydroxypropyle, caprolactone-hydroxyéthyle ou diméthylaminoéthyle. Les copolymères d'acrylate disponibles dans le commerce sont par exemple le Lugalvan DC de la société BASF ou le Carboset 560 de la société BF Goodrich.The organic polymers used are of the copolymer type acrylic, methacrylic or vinyl resins. They are polymers of the ester of acrylic acid or methacrylic acid and may have as their alcohol component an unsubstituted or substituted alkyl group with functional groups, for example a methyl, ethyl, propyl or isopropyl group, n-butyl, isobutyl, tert-butyl, pentyl and hexyl and their isomers and higher homologues, 2-ethylhexyl, phenoxyethyl, hydroxyethyl, 2-hydroxypropyl, caprolactone-hydroxyethyl or dimethylaminoethyl. Commercially available acrylate copolymers are, for example, Lugalvan DC from BASF or Carboset 560 from BF Goodrich.

Comme polymères organiques, on peut utiliser en outre des cires de polyéthylène (sous la forme d'une émulsion, par exemple, le Polygène PE de la société BASF ou le Luciwax EN 41 de la société Morton). Les cires augmentent avantageusement la résistance à l'usure des surfaces et permettent d'obtenir suivant la cire utilisée des propriétés de glissement avantageuses comme un coefficient de frottement bas compris entre 0,08 et 0,18. L'utilisation de cires appropriées dans la suspension permet d'obtenir des valeurs de coefficient de frottement constantes à ± 0,03.As organic polymers, it is also possible to use polyethylene waxes (in the form of an emulsion, for example, Polygene PE from BASF or Luciwax EN 41 from Morton). The waxes advantageously increase the wear resistance of the surfaces and make it possible to obtain, depending on the wax used, advantageous sliding properties, such as a coefficient of low friction of between 0.08 and 0.18. The use of suitable waxes in the suspension makes it possible to obtain constant coefficient of friction values at ± 0.03.

La quantité de polymères organiques ajoutés (exprimée respectivement en matière sèche) est au total de 5 à 150 g/l, de préférence de 10 à 100 g/l. Une combinaison de 5 à 90 g/l de copolymère d'acrylate ou de méthacrylate et de 1 à 60 g/l de cire de polyéthylène s'est avérée très favorable.The amount of organic polymers added (expressed as dry matter, respectively) is in total from 5 to 150 g / l, preferably from 10 to 100 g / l. A combination of 5 to 90 g / l of acrylate or methacrylate copolymer and 1 to 60 g / l of polyethylene wax was found to be very favorable.

Comme oxydes métalliques anticorrosifs, on utilise du dioxyde de silicium, du dioxyde de titane, du dioxyde de zirconium, et/ou des oxydes de terres rares comme de l'oxyde de cérium ou La2O3 ou Y2O3 ou Pr6O11. Ces oxydes métalliques sont utilisés de préférence sous la forme d'une suspension aqueuse de nanoparticules. La concentration des oxydes métalliques (rapportée à la matière solide) dans la suspension aqueuse utilisée dans la deuxième étape du procédé est de préférence de 20 à 60 g/l avec notamment une préférence pour l'intervalle entre 30 et 45 g/l. Les oxydes métalliques sont fixés par les polymères organiques. L'introduction des substances minérales dans la couche anticorrosive sous cette forme a, par rapport au traitement connu par des solutions de ces substances (par exemple des solutions de silicate de sodium) l'avantage d'améliorer la protection vis-à-vis de la corrosion et de maintenir la couleur noire uniforme de la couche anticorrosive au cours du temps.As anticorrosive metal oxides, use is made of silicon dioxide, titanium dioxide, zirconium dioxide, and / or rare earth oxides such as cerium oxide or La 2 O 3 or Y 2 O 3 or Pr 6 O 11 . These metal oxides are preferably used in the form of an aqueous suspension of nanoparticles. The concentration of the metal oxides (relative to the solid material) in the aqueous suspension used in the second stage of the process is preferably from 20 to 60 g / l, in particular with a preference for the interval between 30 and 45 g / l. The metal oxides are fixed by the organic polymers. The introduction of the mineral substances in the anticorrosive layer in this form has, compared to the known treatment with solutions of these substances (for example sodium silicate solutions) the advantage of improving the protection against corrosion and maintain the uniform black color of the anticorrosive layer over time.

L'aspect noir uniforme de la couche anticorrosive peut être encore renforcé par addition de pigments de noir de carbone (par exemple Derussol P130 de la société Degussa) ou d'autres pigments mais tels que le Noir Sanodal commercialisé par la société Clariant dans la suspension aqueuse utilisée au cours de la deuxième étape du procédé. De préférence, la concentration en pigments de noir de carbone dans la suspension aqueuse est comprise entre 5 et 20 g/l.The uniform black appearance of the anticorrosive layer can be further enhanced by addition of carbon black pigments (for example Derussol P130 from Degussa) or other pigments but such as the Black Sanodal marketed by Clariant in the suspension aqueous solution used during the second stage of the process. Preferably, the concentration of carbon black pigments in the aqueous suspension is between 5 and 20 g / l.

La couche de friction ou deuxième strate déposée au deuxième stade a une épaisseur de 0,5 à 5 µ et de préférence de 0,5 à 2,5 µ. La couche anticorrosive a ainsi en tout une épaisseur comprise en général entre 1 µ et 5 µ et de préférence entre 1 µ et 4 µ.The friction layer or second layer deposited in the second stage has a thickness of 0.5 to 5 μ and preferably 0.5 to 2.5 μ. The anticorrosive layer thus has a thickness in general of between 1 μ and 5 μ and preferably between 1 μ and 4 μ.

La couche anticorrosive réalisée en deux étapes selon le procédé suivant l'invention qui vient d'être décrit sur des surfaces métalliques zinguées a un poids de couche dans la première strate (exprimé en Cr) de 0,5 à 4 mg/dm2. Pour déterminer ce poids on dissout la couche de chrome formée (première strate) sur la surface métallique zinguée après la première étape du procédé (passivation) par de l'acide chlorhydrique à 10 % et on détermine la teneur en chrome au moyen d'une spectroscopie d'absorption atomique. La deuxième strate de la couche anticorrosive est constituée d'oxydes métalliques anticorrosifs, de pigments noirs et, le cas échéant, d'autres additifs incorporés dans des polymères organiques. Un avantage de cette couche anticorrosive suivant l'invention réside dans l'absence de Cr6+ et dans une résistance à la corrosion après un chauffage d'une heure à 120°C ou à 150°C, et une résistance au brouillard salin suivant la norme DIN 50 021 de 200 h et parfois bien au-delà.The anticorrosive layer produced in two stages according to the process according to the invention which has just been described on galvanized metal surfaces has a layer weight in the first layer (expressed as Cr) of 0.5 to 4 mg / dm 2 . To determine this weight, the formed chromium layer (first layer) is dissolved on the galvanized metal surface after the first process step (passivation) with 10% hydrochloric acid and the chromium content is determined by means of a atomic absorption spectroscopy. The second layer of the anticorrosive layer consists of anticorrosive metal oxides, black pigments and, if appropriate, other additives incorporated into organic polymers. An advantage of this anticorrosive layer according to the invention lies in the absence of Cr 6+ and in a corrosion resistance after heating for one hour at 120 ° C. or at 150 ° C., and a salt spray resistance according to the invention. the DIN 50 021 standard of 200 hours and sometimes well beyond.

L'invention est décrite plus précisément à l'aide des exemples suivants :The invention is described more precisely with the aid of the following examples:

Exemple 1Example 1

On dissout 19 g de CrO3 dans environ 250 ml d'eau. On y ajoute très lentement 11 g de H2SO4 à 96 %. On y ajoute ensuite 60 g d'H3PO4 à 85 % et on complète par de l'eau à 1 l de solution en tout. La température de la solution s'élève à 65°C environ. La solution est maintenue sous agitation, on ajoute alors avec précaution du formaldéhyde jusqu'à ce que la couleur vire au jaune vert. On refroidit à 25°C environ. A cette solution de Cr3+ on ajoute par litre 30 g d'hypophosphite de sodium et ensuite 20 g d'acide citrique. Le pH est ajusté à 2,7 par une solution de NaOH à 50 % et le mélange est maintenu à une température de 25°C.19 g of CrO 3 are dissolved in approximately 250 ml of water. 11 g of 96% H 2 SO 4 are added very slowly. 60 g of 85% H 3 PO 4 are then added and water is added to 1 liter of solution in all. The temperature of the solution is about 65 ° C. The solution is kept stirring, Carefully add formaldehyde until the color turns green yellow. Cooled to about 25 ° C. To this solution of Cr 3+ is added per liter 30 g of sodium hypophosphite and then 20 g of citric acid. The pH is adjusted to 2.7 with a 50% NaOH solution and the mixture is maintained at a temperature of 25 ° C.

La suspension aqueuse permettant de réaliser la seconde couche est constituée de 90 g/l d'une dispersion colloïdale à 44 % de particules de dioxyde de silicium dans l'eau (Ludox AS 40 de la société Du Pont), de 50 g/l d'un copolymère acrylique à 27 % (Carboset 560 de la société BF Goodrich) et de 70 g/l d'un copolymère acrylique greffé éthylénique (Lugalvan DC de la société BASF). Pour renforcer l'aspect noir de la surface traitée par la suspension, on introduit comme pigment noir dans la solution aqueuse 50 g/l d'une dispersion de noir de carbone à 20 % (Derussol P 130 de la société Degussa).The aqueous suspension making it possible to produce the second layer consists of 90 g / l of a colloidal dispersion containing 44% of silicon dioxide particles in water (Ludox AS 40 from Du Pont), of 50 g / l of a 27% acrylic copolymer (Carboset 560 from the company BF Goodrich) and 70 g / l of an ethylenic grafted acrylic copolymer (Lugalvan DC from BASF). To reinforce the black appearance of the surface treated with the suspension, 50 g / l of a 20% carbon black dispersion (Derussol P 130 from Degussa) is introduced as a black pigment into the aqueous solution.

On revêt des plaques d'acier standard de 100 mm x 70 mm d'une manière classique d'un alliage de zinc/fer (Fe 0,5 %), on les active dans une solution d'acide nitrique à 5 ml/l, puis après rinçage on les plonge pendant 180 secondes environ dans la solution de Cr3+ (température de la solution 25°C), on les rince, on les égoutte dans un courant d'air (température ambiante), on les trempe pendant 30 secondes environ dans la suspension aqueuse et on les sèche pendant 15 minutes environ dans un courant d'air chaud (70°C). L'aspect des plaques est alors noir uniforme. La teneur en chrome de la couche anticorrosion est (avant le traitement par la suspension aqueuse) de 2 mg/dm2. On porte les plaques d'acier ainsi traitées pendant 1 h à 150°C (choc thermique) et on les soumet ensuite à un essai au brouillard salin suivant la norme DIN 50 021. On observe une apparition de rouille blanche après 300 h.Standard 100 mm × 70 mm steel plates are coated in a conventional zinc / iron alloy (0.5% Fe), activated in a 5 ml / l nitric acid solution. then, after rinsing, they are immersed for approximately 180 seconds in the Cr 3+ solution (temperature of the solution 25 ° C.), rinsed, drained in a stream of air (room temperature), quenched during 30 seconds in the aqueous suspension and dried for about 15 minutes in a hot air stream (70 ° C). The appearance of the plates is then black uniform. The chromium content of the anticorrosion layer is (before treatment with the aqueous suspension) 2 mg / dm 2 . The steel plates thus treated are heated for 1 hour at 150 ° C. (thermal shock) and then subjected to a salt spray test according to DIN 50 021. An appearance of white rust is observed after 300 hours.

Exemple 2Example 2

On dilue 60 g d'une solution de nitrate de chrome (teneur en chrome 11,5 %) dans 200 ml d'eau. On y ajoute 20 g d'acide phosphorique à 85 %, 0,3 g d'acide nitrique à 69 %, et 75 g de de dispersion de silice colloïdale type Ludox AM 30 et on ajuste le volume à 1 litre avec de l'eau. On règle le pH entre 1,5 et 1,6 à l'aide d'une solution de NaOH à 50 %.60 g of a solution of chromium nitrate (11.5% chromium content) in 200 ml of water are diluted. 20 g of 85% phosphoric acid, 0.3 g of 69% nitric acid and 75 g of colloidal silica dispersion type Ludox AM 30 are added thereto and the volume is adjusted to 1 liter with water. water. The pH is adjusted to between 1.5 and 1.6 with 50% NaOH solution.

On revêt d'une manière classique des plaques d'acier standard de 100 mm x 70 mm d'un alliage de zinc/nickel (Ni 12 à 15 %), on les trempe pendant 90 secondes environ dans la solution de Cr3+ (température de la solution 25°C), on les rince, on les égoutte dans un courant d'air (température ambiante), on les trempe pendant 30 secondes environ dans la suspension aqueuse (de l'exemple 1) et on les sèche pendant 10 minutes environ dans un courant d'air chaud (70°C). Les plaques d'acier présentent un aspect noir uniforme. La teneur en chrome de la couche anticorrosion est (avant le traitement par la suspension aqueuse) > 2 mg/dm2. Les plaques d'acier ainsi traitées sont portées pendant 1 h à 120°C (choc thermique) et soumises ensuite à un essai au brouillard salin suivant la norme DIN 50 021. Les pièces ne présentent pas de rouille blanche après 240 heures et pas de rouille rouge après 800 heures.Standard steel plates are conventionally coated 100 mm x 70 mm of a zinc / nickel alloy (Ni 12 to 15%), soaked for about 90 seconds in the solution of Cr 3+ (temperature of the solution 25 ° C), rinsed, they are drained in a stream of air (room temperature), quenched for about 30 seconds in the aqueous suspension (of Example 1) and dried for about 10 minutes in a stream of hot air (70 ° C.). VS). The steel plates have a uniform black appearance. The chromium content of the anticorrosion layer is (before treatment with the aqueous suspension)> 2 mg / dm 2 . The steel plates thus treated are heated for 1 hour at 120 ° C (thermal shock) and then subjected to a salt spray test according to DIN 50 021. The parts do not exhibit white rust after 240 hours and no red rust after 800 hours.

Exemple 3Example 3

La solution de Cr3+ est constituée de 55 g/l de Chromitan (marque de fabrique) (sel à base de sulfate de chrome (III)), ce qui correspond à une teneur en Cr3+ de la solution de 9,35 g/l, de 25,5 g/l d'H3PO4, de 30 g/l d'hypophosphite de sodium, de 20 g/l d'acide citrique et de 0,9 g/l d'HNO3, le pH de la solution est ajusté à 2,5 à l'aide d'une solution de NaOH 20%.The Cr 3+ solution consists of 55 g / l of Chromitan (trade name) (chromium (III) sulphate salt), which corresponds to a Cr 3+ content of the 9.35 solution. g / l, 25.5 g / l H 3 PO 4 , 30 g / l sodium hypophosphite, 20 g / l citric acid and 0.9 g / l HNO 3 the pH of the solution is adjusted to 2.5 with 20% NaOH solution.

La suspension aqueuse permettant de réaliser la seconde couche est constituée de 90g/l d'une dispersion colloïdale à 44% de particules de dioxyde de silicium dans l'eau (Ludox AS40 de la société Du Pont), de 50g/l d'un copolymère acrylique à 27% (Carboset 560 de la société BF Goolrich) et de 70g/l d'un copolymère acrylique greffé éthylénique (Cugalvan DC de la société BASF)The aqueous suspension making it possible to produce the second layer consists of 90 g / l of a colloidal dispersion containing 44% of silicon dioxide particles in water (Ludox AS40 from Du Pont), 50 g / l of 27% acrylic copolymer (Carboset 560 from the company BF Goolrich) and 70 g / l of an ethylenic grafted acrylic copolymer (Cugalvan DC from BASF)

On revêt d'une manière classique des plaques d'acier standard de 100 mm x 70 mm d'un alliage de zinc/fer (Fe 0,5 %), on les nettoie, on les plonge pendant 240 secondes environ dans la solution de Cr3+ (température de la solution 25°C), on les rince, on les égoutte dans un courant d'air (température ambiante), on les trempe pendant 30 secondes environ dans la suspension aqueuse décrite ci-dessus et on les sèche pendant 15 minutes environ dans un courant d'air chaud (70°C). L'aspect des plaques est alors noir uniforme. La teneur en chrome de la couche anticorrosion est (avant le traitement par la suspension aqueuse) supérieure à 2 mg/dm2. On porte les plaques d'acier ainsi traitées pendant 1 h à 120°C (choc thermique) et on les soumet ensuite à un essai au brouillard salin suivant la norme DIN 50021. Les pièces ne présentent pas de rouille blanche après 320 heures.Standard 100 mm x 70 mm steel plates of a zinc / iron alloy (0.5% Fe) were conventionally coated, cleaned and immersed for about 240 seconds in Cr 3+ (temperature of the solution 25 ° C), rinsed, drained in a stream of air (room temperature), soaked for about 30 seconds in the aqueous suspension described above and dried for about 15 minutes in a stream of hot air (70 ° C). The appearance of the plates is then black uniform. The chromium content of the anticorrosion layer is (before treatment with the aqueous suspension) greater than 2 mg / dm 2 . We wear them steel plates treated for 1 hour at 120 ° C (thermal shock) and then subjected to a salt spray test according to DIN 50021. The parts do not exhibit white rust after 320 hours.

Exemple 4Example 4

On dissout 45 g (correspondant à une teneur en Cr3+ de 7,65 g) de Chromitan (marque de fabrique) (sel à base de sulfate de chrome (III)) dans 500 ml d'eau, et on amène le pH au-dessus de 5 par addition d'une solution à 20% de NaOH. A cette solution on ajoute 45 g d'hypophosphite de sodium et 54 g d'acide phosphorique à 85 % et on complète la solution à 1 1 par de l'eau.45 g (corresponding to a Cr 3+ content of 7.65 g) of Chromitan (trade name) (salt based on chromium (III) sulphate) are dissolved in 500 ml of water, and the pH is brought above 5 by addition of a 20% solution of NaOH. To this solution are added 45 g of sodium hypophosphite and 54 g of 85% phosphoric acid and the solution is made up to 1 liter with water.

On filtre la solution sur un papier filtre ayant un diamètre de pore de 100 µm et on la porte pendant 2 h à 60°C. On règle le pH entre 2,3 et 2,5 par une solution de NaOH à 50 %. A cette solution on ajoute 1 g de sulfate de cobalt CoSO4, 7H2O.The solution is filtered through a filter paper having a pore diameter of 100 μm and is heated for 2 hours at 60 ° C. The pH is adjusted to between 2.3 and 2.5 with 50% NaOH solution. To this solution is added 1 g of cobalt sulfate CoSO 4 , 7H 2 O.

On revêt de manière classique des plaques d'acier standard de 100 mm x 70 mm d'un alliage de zinc/fer (Fe 0,5 %), on les active dans une solution d'acide nitrique à 5 ml/l, on les trempe pendant 60 secondes environ dans la solution de Cr3+ (température de la solution 25°C), on les rince et on les égoutte dans un courant d'air (température ambiante). L'aspect des plaques est alors noir uniforme. La teneur en chrome de la couche anticorrosion est supérieure à 2 mg/dm2.Standard steel plates of 100 mm x 70 mm of a zinc / iron alloy (0.5% Fe) are conventionally coated, activated in a 5 ml / l nitric acid solution, soaking them for about 60 seconds in the Cr 3+ solution (solution temperature 25 ° C), rinsing them and draining them in a stream of air (room temperature). The appearance of the plates is then black uniform. The chromium content of the anticorrosion layer is greater than 2 mg / dm 2 .

On plonge les plaques d'acier ainsi traitées pendant 30 secondes environ dans la suspension aqueuse (exemple 1) et on les sèche pendant 15 minutes environ dans un courant d'air chaud (70°C), on les porte pendant 24 h à 120°C (choc thermique) et on les soumet ensuite à un essai au brouillard salin suivant la norme DIN 50021. Après 300 h, on n'observe pas de rouille blanche.The steel plates thus treated are immersed for about 30 seconds in the aqueous suspension (Example 1) and dried for about 15 minutes in a stream of hot air (70 ° C.) and heated for 24 hours at 120 ° C. ° C (thermal shock) and then subjected to a salt spray test according to DIN 50021. After 300 h, no white rust was observed.

Exemple 5Example 5

On dissout 100 g de KCr(SO4)2, 12H2O dans 200 ml d'eau. On dissout 20 g de NaOH dans 100 ml environ et on les y ajoute. On porte à 80°C pendant 1 h. Après refroidissement à 25°C environ, on ajoute 20 g d'hypophosphite de sodium, 20 g d'acide citrique, 15 g d'acide phosphorique à 85 %, 0,6 g d'acide nitrique à 69 % et 100 g de dispersion de silice type Ludox AM30, on complète ensuite la solution à 1 1 par de l'eau. Le pH de la solution est de 2,5.100 g of KCr (SO 4 ) 2 , 12H 2 O are dissolved in 200 ml of water. 20 g of NaOH are dissolved in about 100 ml and added thereto. It is heated at 80 ° C. for 1 hour. After cooling to about 25 ° C., 20 g of sodium hypophosphite, 20 g of citric acid, 15 g of 85% phosphoric acid, 0.6 g of 69% nitric acid and 100 g of typical silica dispersion Ludox AM30, the solution is then added to 1 1 with water. The pH of the solution is 2.5.

On revêt de manière classique des plaques d'acier standard de 100 mm x 70 mm d'un alliage de zinc/fer (Fe 0,5 %), on les active dans une solution d'acide nitrique à 5 ml/l, on les trempe pendant 180 secondes dans la solution de Cr3+ (température de la solution 25°C), on les rince et on les égoutte dans un courant d'air (température ambiante). Les plaques d'acier présentent un aspect noir uniforme. La teneur en chrome de la couche anticorrosive est comprise entre 2 et 4 mg/dm2.Standard steel plates of 100 mm x 70 mm of a zinc / iron alloy (0.5% Fe) are conventionally coated, activated in a 5 ml / l nitric acid solution, soaking them for 180 seconds in the Cr 3+ solution (solution temperature 25 ° C), rinsing them and draining them in a stream of air (room temperature). The steel plates have a uniform black appearance. The chromium content of the anticorrosive layer is between 2 and 4 mg / dm 2 .

On trempe les plaques d'acier pendant 30 secondes environ dans la suspension aqueuse (de l'exemple 1) et on les sèche pendant 15 minutes environ dans un courant d'air chaud (70°C), on les porte pendant 24 h à 120°C (choc thermique) et ensuite on les soumet à un essai au brouillard salin suivant la norme DIN 50 021. Après 200 h, on n'observe pas de rouille blanche.The steel plates are quenched for about 30 seconds in the aqueous suspension (of Example 1) and dried for about 15 minutes in a stream of hot air (70 ° C.) and heated for 24 hours. 120 ° C (thermal shock) and then subjected to a salt spray test according to DIN 50 021. After 200 h, no white rust was observed.

Exemple 6Example 6

On ajoute 35 g d'une solution de nitrate de chrome (teneur en chrome 11,5 %) dans 100 ml d'eau. On y ajoute 6,5 g de NaOH, 15 g d'acide oxalique et 2 g d'acide malonique. La température devient supérieure à 60°C. Après refroidissement à 25°C, on ajoute 2 g de Co(NO3)2, 6H2O, et on complète la solution à 1 l par de l'eau. On règle le pH à 1,5.35 g of a solution of chromium nitrate (11.5% chromium content) in 100 ml of water are added. 6.5 g of NaOH, 15 g of oxalic acid and 2 g of malonic acid are added. The temperature becomes higher than 60 ° C. After cooling to 25 ° C., 2 g of Co (NO 3 ) 2 , 6H 2 O are added and the solution is made up to 1 liter with water. The pH is adjusted to 1.5.

On revêt de manière classique des plaques d'acier standard de 100 mm x 70 mm d'un alliage de zinc/nickel (Ni 15 %) de 12 µm d'épaisseur, on les trempe pendant 75 secondes dans la solution de Cr3+ (température de la solution 25°C), on les rince et on les égoutte dans un courant d'air (température ambiante). Les plaques d'acier présentent un aspect noir uniforme. La teneur en chrome de la couche anticorrosive est de 2 mg/dm2.Standard 100 mm x 70 mm steel plates are conventionally coated with a 12 μm thick zinc / nickel (Ni 15%) alloy, soaked in the Cr 3+ solution for 75 seconds. (temperature of the solution 25 ° C), rinsed and drained in a stream of air (room temperature). The steel plates have a uniform black appearance. The chromium content of the anticorrosive layer is 2 mg / dm 2 .

On trempe les plaques d'acier pendant 30 secondes environ dans la suspension aqueuse (de l'exemple 3) et on les sèche pendant 15 minutes environ dans un courant d'air chaud (70°C).The steel plates are quenched for about 30 seconds in the aqueous suspension (of Example 3) and dried for about 15 minutes in a stream of hot air (70 ° C).

On porte alors les plaques pendant 1 h à 120°C (choc thermique), et on les soumet ensuite à un essai au brouillard salin suivant la norme DIN 50 021. Après 200 h, on n'observe pas de rouille blanche, et après 800 h on n'observe pas de rouille rouge.The plates are then heated for one hour at 120 ° C. (thermal shock), and then subjected to a salt spray test according to DIN 50 021. After 200 hours, no white rust is observed, and after 800 h, no red rust is observed.

Claims (11)

  1. Process for depositing a black anti-corrosive layer on a zinc alloy, consisting of treating the zinc alloy in a first step of the process with an aqueous acidic solution of Cr3+ free from Cr6+, containing a complexing agent or a plurality of complexing agents, and in a second step of the process treating the zinc alloy thus passivated with an aqueous suspension containing an organic polymer, an anti-corrosive metal oxide selected from among silicon dioxide, titanium dioxide, zirconium dioxide and/or rare earth oxides such as cerium oxide, or La2O3 or Y2O3 or Pr6O11 and preferably a black pigment, thus depositing a second stratum 0.5 to 5 µm thick, preferably 0.5 to 2.5 µm thick.
  2. Process according to claim 1, characterised in that in the first step of the process the pH of the Cr3+ solution ranges from 1 to 4.
  3. Process according to claim 2, characterised in that in the first step of the process the pH of the Cr3+ solution ranges from 1.0 to 3.0.
  4. Process according to one of claims 1 to 3, characterised in that it comprises using, as complexing agent, a phosphate, a hypophosphite, citric acid, oxalic acid, tartaric acid, malonic acid, maleic acid, formic acid, acetic acid, lactic acid, aminoacetic acid, iminodiacetic acid or urea.
  5. Process according to one of claims 1 to 4, characterised in that it comprises, in the first step of the process, adding Fe, Co, Mo and/or Ni ions to the Cr3+ solution in an amount of from 0.001 mol/l to 0.1 mol/l.
  6. Process according to one of claims 1 to 5, characterised in that it comprises, in the first step of the process, adding colloidal particles of silicon dioxide to the Cr3+ solution in an amount that may vary from 0.07 mol/l to 1.3 mol/l.
  7. Process according to one of claims 1 to 6, characterised in that it comprises using, as organic polymers, acrylate or methacrylate copolymers, polyethylene wax or vinyl resins.
  8. Process according to one of claims 1 to 7, characterised in that it comprises depositing the second stratum by immersion.
  9. Process according to one of claims 1 to 8, characterised in that the anti-corrosive metal oxides are in the form of a suspension of nanoparticles.
  10. Black anti-corrosive layer on a zinc alloy, characterised in that it comprises two strata, in that it can be prepared by a process according to one of claims 1 to 9 and in that the first stratum has a weight (expressed in Cr) of 1 to 4 mg/dm2.
  11. Layer according to claim 10, characterised in that it has a thickness of between 1 µm and 5 µm and preferably between 1 µm and 4 µm and the second stratum has a thickness of between 0.5 µm and 5 µm and preferably between 0.5 µm and 2.5 µm.
EP01958148A 2000-07-25 2001-07-20 Anticorrosive black coating on zinc alloy and method for making same Expired - Lifetime EP1409157B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR0009716 2000-07-25
FR0009716A FR2812307B1 (en) 2000-07-25 2000-07-25 ANTI-CORROSIVE BLACK LAYER ON A ZINC ALLOY AND PROCESS FOR PREPARING THE SAME
PCT/FR2001/002376 WO2002007902A2 (en) 2000-07-25 2001-07-20 Anticorrosive black coating on zinc alloy and method for making same

Publications (2)

Publication Number Publication Date
EP1409157A2 EP1409157A2 (en) 2004-04-21
EP1409157B1 true EP1409157B1 (en) 2007-04-11

Family

ID=8852874

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01958148A Expired - Lifetime EP1409157B1 (en) 2000-07-25 2001-07-20 Anticorrosive black coating on zinc alloy and method for making same

Country Status (5)

Country Link
EP (1) EP1409157B1 (en)
DE (1) DE60127870T2 (en)
ES (1) ES2282278T3 (en)
FR (1) FR2812307B1 (en)
WO (1) WO2002007902A2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009045569A1 (en) 2009-10-12 2011-04-14 Dr.-Ing. Max Schlötter GmbH & Co KG Black passivation of zinc and zinc iron layers

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3774415B2 (en) * 2002-03-14 2006-05-17 ディップソール株式会社 A treatment solution for forming a black hexavalent chromium-free conversion coating on zinc and zinc alloy plating and a method of forming a black hexavalent chromium-free conversion coating on zinc and zinc alloy plating.
US20050109426A1 (en) 2002-03-14 2005-05-26 Dipsol Chemicals Co., Ltd. Processing solution for forming hexavalent chromium free, black conversion film on zinc or zinc alloy plating layers, and method for forming hexavalent chromium free, black conversion film on zinc or zinc alloy plating layers
US20040156999A1 (en) * 2003-02-07 2004-08-12 Pavco, Inc. Black trivalent chromium chromate conversion coating
US20060003901A1 (en) * 2004-07-02 2006-01-05 Henkel Kommanditgesellschaft Auf Aktien (Henkel Kgaa) Dry film lubricant
US20070243397A1 (en) * 2006-04-17 2007-10-18 Ludwig Robert J Chromium(VI)-free, aqueous acidic chromium(III) conversion solutions
EP2014793B1 (en) 2007-06-14 2013-11-20 Atotech Deutschland GmbH Anti-corrosion treatment for conversion coatings
EP2281923A1 (en) 2009-07-03 2011-02-09 ATOTECH Deutschland GmbH Corrosion protection treatment for surfaces made of zinc and zinc coatings
JP2013249528A (en) * 2012-06-04 2013-12-12 Dipsol Chemicals Co Ltd Trivalent chromium-conversion processing solution containing aluminum-modified colloidal silica
JP6283857B2 (en) * 2013-08-28 2018-02-28 ディップソール株式会社 Black fastening member for vehicles with excellent corrosion resistance and black appearance
ES2747838T3 (en) 2014-04-16 2020-03-11 Doerken Ewald Ag Procedure for Producing a Dark Corrosion Protective Coating
ES2556680B1 (en) * 2014-07-18 2016-11-03 Moreda - Riviere Trefilerías, S.A. Coated wire, procedure for obtaining it and mesh comprising it
EP3246429A1 (en) * 2016-05-20 2017-11-22 ATOTECH Deutschland GmbH Aqueous zink passivation composition and method for passivation of a zinc surface using such a composition
ES2646237B2 (en) * 2017-09-28 2018-07-27 Avanzare Innovacion Tecnologica S.L. Formulation for the biting of polymeric materials prior to coating them
JP2017226925A (en) * 2017-10-05 2017-12-28 ディップソール株式会社 Trivalent chromium chemical conversion treatment liquid containing aluminum modified colloidal silica
US20220119959A1 (en) 2019-02-28 2022-04-21 Atotech Deutschland Gmbh Aqueous post treatment composition and method for corrosion protection
EP3771748A1 (en) * 2019-07-30 2021-02-03 Dr.Ing. Max Schlötter GmbH & Co. KG Chromium (vi) and cobalt-free black passivation for zinc nickel surfaces

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3392008B2 (en) * 1996-10-30 2003-03-31 日本表面化学株式会社 Metal protective film forming treatment agent and treatment method
US3900689A (en) * 1970-04-02 1975-08-19 Du Pont Substrates treated with chromium(iii) complexes to increase the adhesion of organic polymers thereto
CA1228000A (en) * 1981-04-16 1987-10-13 David E. Crotty Chromium appearance passivate solution and process
JP2844953B2 (en) * 1991-03-29 1999-01-13 日本鋼管株式会社 Weldable colored steel plate
US5415702A (en) * 1993-09-02 1995-05-16 Mcgean-Rohco, Inc. Black chromium-containing conversion coatings on zinc-nickel and zinc-iron alloys
EP0970757B1 (en) * 1998-07-07 2002-10-30 Kabushiki Kaisha Nippankenkyusho Rust preventive coating and method for forming the same
US6224657B1 (en) * 1998-10-13 2001-05-01 Sermatech International, Inc. Hexavalent chromium-free phosphate-bonded coatings

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009045569A1 (en) 2009-10-12 2011-04-14 Dr.-Ing. Max Schlötter GmbH & Co KG Black passivation of zinc and zinc iron layers
EP2319957A1 (en) 2009-10-12 2011-05-11 Dr.Ing. Max Schlötter GmbH & Co. KG Black passivation of zinc and zinc-iron layers

Also Published As

Publication number Publication date
DE60127870T2 (en) 2008-01-17
EP1409157A2 (en) 2004-04-21
ES2282278T3 (en) 2007-10-16
FR2812307B1 (en) 2003-02-14
FR2812307A1 (en) 2002-02-01
WO2002007902A3 (en) 2002-06-20
DE60127870D1 (en) 2007-05-24
WO2002007902A2 (en) 2002-01-31

Similar Documents

Publication Publication Date Title
EP1409157B1 (en) Anticorrosive black coating on zinc alloy and method for making same
US4278477A (en) Metal treatment
JPS6352114B2 (en)
US8262811B2 (en) Aqueous reaction solution and method of passivating workpieces having zinc or zinc alloy surfaces and use of a heteroaromatic compound
FR2496707A1 (en) SURFACE TREATED STEEL SHEETS FOR PAINT APPLICATION
JPH0324295A (en) Production of black surface-treated steel sheet
JP4189884B2 (en) Chromium-free chemical conversion treatment solution and treatment method
JP2007023353A (en) Non-chromium reactive chemical conversion treatment of galvanized member
KR20130109938A (en) Process for forming corrosion protection layers on metal surfaces
JPWO2015029836A1 (en) Friction modifier for topcoat agent of trivalent chromium conversion coating or chromium-free conversion coating and topcoat agent containing the same
JP2775210B2 (en) Method for sealing chromate conversion coating on electroplated zinc
JP5520439B2 (en) Method for producing surface-adjusted aluminum casting
US4939001A (en) Process for sealing anodized aluminum
JPH0352557B2 (en)
EP0390348B1 (en) Method for producing resin-coated rust-proof steel sheets with properties suitable for electrodeposition coating
KR100326653B1 (en) Manufacturing method of hot-dip galvanized steel sheet containing chromate treatment with excellent black resistance and whiteness
JP3278475B2 (en) Trivalent chromium compound sol composition and method for producing the same
US4351675A (en) Conversion coatings for zinc and cadmium surfaces
JPS63195296A (en) Production of colored surface-treated steel sheet
JP5660751B2 (en) Chemical conversion aqueous solution for forming a chromium-free conversion coating on zinc or zinc alloy plating and a chromium-free conversion coating obtained therefrom
JP2787365B2 (en) Organic thin film coated Cr-containing zinc-based multi-layer rust-proof steel sheet having excellent long-term adhesion of organic thin film and cationic electrodeposition coating property, and method for producing the same
JPH0419307B2 (en)
JP3212754B2 (en) Water-based inorganic paint coating pretreatment method for aluminum-based metal surfaces
CA2118856A1 (en) Enhanced corrosion resistant one-step coatings and treated metallic substrates
JPH0211799A (en) Zn-based surface-treated steel sheet having excellent corrosion resistance after coating

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20030624

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

17Q First examination report despatched

Effective date: 20060807

RIC1 Information provided on ipc code assigned before grant

Ipc: C23C 22/53 20060101ALI20061117BHEP

Ipc: C23C 22/06 20060101ALI20061117BHEP

Ipc: B05D 5/06 20060101AFI20061117BHEP

Ipc: C23C 28/00 20060101ALI20061117BHEP

RBV Designated contracting states (corrected)

Designated state(s): DE ES FR IT SE

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE ES FR IT SE

REF Corresponds to:

Ref document number: 60127870

Country of ref document: DE

Date of ref document: 20070524

Kind code of ref document: P

REG Reference to a national code

Ref country code: SE

Ref legal event code: TRGR

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2282278

Country of ref document: ES

Kind code of ref document: T3

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20080114

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 20120719

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20120726

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20130618

Year of fee payment: 13

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20130709

Year of fee payment: 13

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20130711

Year of fee payment: 13

REG Reference to a national code

Ref country code: SE

Ref legal event code: EUG

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130721

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20140908

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130721

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 60127870

Country of ref document: DE

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20150331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20150203

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140720

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 60127870

Country of ref document: DE

Effective date: 20150203

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140731