EP4081672A1 - Systèmes et procédés de traitement d'un substrat métallique - Google Patents

Systèmes et procédés de traitement d'un substrat métallique

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Publication number
EP4081672A1
EP4081672A1 EP20845479.3A EP20845479A EP4081672A1 EP 4081672 A1 EP4081672 A1 EP 4081672A1 EP 20845479 A EP20845479 A EP 20845479A EP 4081672 A1 EP4081672 A1 EP 4081672A1
Authority
EP
European Patent Office
Prior art keywords
composition
substrate
present
conversion
sealing
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.)
Withdrawn
Application number
EP20845479.3A
Other languages
German (de)
English (en)
Inventor
Gordon L. POST
Michael A. Mayo
Justin J. Martin
Abdulrahman D. IBRAHIM
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.)
PRC Desoto International Inc
Original Assignee
PRC Desoto International Inc
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 PRC Desoto International Inc filed Critical PRC Desoto International Inc
Publication of EP4081672A1 publication Critical patent/EP4081672A1/fr
Withdrawn legal-status Critical Current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
    • C23C22/34—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/78—Pretreatment of the material to be coated
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/82—After-treatment
    • C23C22/83—Chemical after-treatment
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2222/00—Aspects relating to chemical surface treatment of metallic material by reaction of the surface with a reactive medium
    • C23C2222/10—Use of solutions containing trivalent chromium but free of hexavalent chromium

Definitions

  • the present invention relates to compositions, systems and methods for treating a substrate.
  • the present invention also relates to a substrate obtainable by treatment with the systems and methods.
  • an inorganic protective coating can be applied to the metal surface.
  • This inorganic protective coating also referred to as a conversion coating, may be the only coating applied to the metal substrate or the coating may be an intermediate coating to which subsequent coatings are applied.
  • a system for treating a substrate comprising: a conversion composition comprising trivalent chromium in an amount of 0.001 g/L to 20 g/L based on total weight of the conversion composition; and a sealing composition comprising an ammonium- containing compound.
  • Also disclosed herein is a method of treating a metal substrate comprising: contacting at least a portion of the surface of the substrate with a conversion composition comprising a trivalent chromium in an amount of 0.001 g/L to 20 g/L based on total weight of the conversion composition; and contacting the portion of the substrate surface that has been treated with the conversion composition with a sealing composition comprising an ammonium- containing compound.
  • a substrate obtainable by treatment with a system of the present invention and/or obtainable by the method of treating of the present invention.
  • Fig. 1 shows an XPS depth profile of (A) substrate treated according to Example
  • each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
  • a closed or open-ended numerical range is described herein, all numbers, values, amounts, percentages, subranges and fractions within or encompassed by the numerical range are to be considered as being specifically included in and belonging to the original disclosure of this application as if these numbers, values, amounts, percentages, subranges and fractions had been explicitly written out in their entirety.
  • the terms “on,” “onto,” “applied on,” “applied onto,” “formed on,” “deposited on,” “deposited onto,” mean formed, overlaid, deposited, and/or provided on but not necessarily in contact with the surface.
  • a coating layer “formed over” a substrate does not preclude the presence of one or more other intervening coating layers of the same or different composition located between the formed coating layer and the substrate.
  • the term “substantially free,” when used with respect to the absence of a particular material, means that such material, if present at all in a composition, a bath containing the composition, and/or layers formed from and comprising the composition, only is present in a trace amount of 5 ppm or less based on a total weight of the composition or layer(s), as the case may be, excluding any amount of such material that may be present or derived as a result of drag-in, substrate(s), and/or dissolution of equipment.
  • the term “essentially free,” when used with respect to the absence of a particular material, means that such material, if present at all in a composition, a bath containing the composition, and/or layers formed from and comprising the composition, only is present in a trace amount of 1 ppm or less based on a total weight of the composition or layer(s), as the case may be.
  • the term “completely free,” when used with respect to the absence of a particular material, means that such material, if present at all in a composition, a bath containing the composition, and/or layers formed from and comprising the composition, is absent from the composition, the bath containing the composition, and/or layers formed from and comprising same (i.e., the composition, bath containing the composition, and/or layers formed from and comprising the composition contain 0 ppm of such material).
  • salt refers to an ionic compound made up of cations and anions and having an overall electrical charge of zero. Salts may be hydrated or anhydrous.
  • aqueous composition refers to solution or dispersion in a medium that comprises predominantly water.
  • the aqueous composition may comprise water in an amount of more than 50 wt.%, or more than 70 wt.% or more than 80 wt.% or more than 90 wt.% or more than 95 wt.%, based on the total weight of the composition.
  • the aqueous medium may for example consist substantially of water.
  • the aqueous composition may comprise solutes or dispersants in an amount of at least 5 wt.%, such as at least 10 wt.%, such as at least 20 wt.%, such as at least 30 wt.%, such as at least 40 wt.%, such as at least 50 wt.% based on total weight of the aqueous composition.
  • conversion composition refers to a composition that is capable of reacting with and chemically altering the substrate surface and binding to it to form a film that affords corrosion protection.
  • a “sealing composition” refers to a composition, e.g. a solution or dispersion, that affects a substrate surface or a material deposited onto a substrate surface in such a way as to alter the physical and/or chemical properties of the substrate surface (i.e., the composition affords corrosion protection) and that is applied to at least a portion of the substrate surface following treatment of the surface with a conversion composition.
  • a “system” refers to a plurality of treatment compositions
  • the system may be part of a production line (such as a factory production line) that produces a finished substrate or a treated substrate that is suitable for use in other production lines.
  • ammonium-containing compound refers to a compound that contains the NH4 + cation.
  • transition metal refers to an element that is in any of
  • transition metal compound refers to compounds that include at least one element that is a transition metal of the CAS version of the Periodic Table of the Elements.
  • Group IA metal refers to an element that is in Group
  • Group IA metal compound refers to compounds that include at least one element that is in Group IA of the CAS version of the Periodic Table of the Elements.
  • Group IIA metal refers to an element that is in Group
  • Group IIA metal compound refers to compounds that include at least one element that is in Group IIA of the CAS version of the Periodic Table of the Elements.
  • Group MB metal refers to yttrium and scandium of the
  • Group IIIB metal expressly excludes lanthanide series elements.
  • Group MB metal compound refers to compounds that include at least one element that is in group MB of the CAS version of the Periodic Table of the Elements as defined above.
  • Group IVB metal refers to an element that is in group
  • Group IVB metal compound refers to compounds that include at least one element that is in Group IVB of the CAS version of the Periodic Table of the Elements.
  • Group VB metal refers to an element that is in group
  • Group VB metal compound refers to compounds that include at least one element that is in Group VB of the CAS version of the Periodic Table of the Elements.
  • Group VIB metal refers to an element that is in group
  • Group VIB metal compound refers to compounds that include at least one element that is in Group VIB of the CAS version of the Periodic Table of the Elements.
  • Group VIIB metal refers to an element that is in group
  • Group VIIB metal compound refers to compounds that include at least one element that is in Group VIIB of the CAS version of the Periodic Table of the Elements.
  • Group IIB metal refers to an element that is in group
  • Group IIB metal compound refers to compounds that include at least one element that is in Group IIB of the CAS version of the Periodic Table of the Elements.
  • lanthanide series elements refers to elements 57-71 of the CAS version of the Periodic Table of the Elements and includes elemental versions of the lanthanide series elements. According to the invention, the lanthanide series elements may be those which have both common oxidation states of +3 and +4, referred to hereinafter as +3/+4 oxidation states.
  • the term “lanthanide compound” refers to compounds that include at least one of elements 57-71 of the CAS version of the Periodic Table of the Elements.
  • halogen refers to any of the elements fluorine, chlorine, bromine, iodine, and astatine of the CAS version of the Periodic Table of the Elements, corresponding to Group VIIA of the periodic table.
  • halide refers to compounds that include at least one halogen.
  • aluminum when used in reference to a substrate, refers to substrates made of or comprising aluminum and/or aluminum alloy, and clad aluminum substrates.
  • Pitting corrosion is the localized formation of corrosion by which cavities or holes are produced in a substrate.
  • the term “pit,” as used herein, refers to such cavities or holes resulting from pitting corrosion and is characterized by (1) a rounded, elongated or irregular appearance when viewed normal to the test panel surface, (2) a “comet-tail”, a line, or a “halo” (i.e., a surface discoloration) emanating from the pitting cavity, and (3) the presence of corrosion byproduct (e.g., white, grayish or black granular, powdery or amorphous material) inside or immediately around the pit.
  • An observed surface cavity or hole must exhibit at least two of the above characteristics to be considered a corrosion pit. Surface cavities or holes that exhibit only one of these characteristics may require additional analysis before being classified as a corrosion pit.
  • total composition weight refers to the total weight of all ingredients being present in the respective composition including any carriers and solvents.
  • the present invention is directed to a system for treating a metal substrate comprising, or in some instances, consisting essentially of, or in some instances, consisting of: a conversion composition comprising trivalent chromium in an amount of 0.001 g/L to 20 g/L based on total weight of the conversion composition; and a sealing composition comprising an ammonium-containing compound.
  • the present invention also is directed to a method of treating a metal substrate comprising, or in some instances, consisting essentially of, or in some instances, consisting of: contacting at least a portion of a surface of the substrate with a conversion composition comprising trivalent chromium in an amount of 0.001 g/L to 20 g/L based on total weight of the conversion composition; and contacting at least a portion of the surface that has been contacted with the conversion composition with a sealing composition comprising ammonium-containing compound.
  • Suitable substrates that may be used in the present invention include metal substrates, metal alloy substrates, and/or substrates that have been metallized, such as nickel- plated plastic.
  • the metal or metal alloy can comprise or be steel, aluminum, zinc, nickel, and/or magnesium.
  • the steel substrate could be cold rolled steel, hot rolled steel, electrogalvanized steel, and/or hot dipped galvanized steel.
  • Aluminum alloys of the 1XXX, 2XXX, 3 XXX, 4 XXX, 5 XXX, 6XXX, or 7XXX series as well as clad aluminum alloys also may be used as the substrate.
  • Aluminum alloys may comprise 0.01% by weight copper to 10% by weight copper.
  • Aluminum alloys which are treated may also include castings, such as 1XX.X, 2XX.X, 3XX.X, 4XX.X, 5XX.X, 6XX.X, 7XX.X,
  • the substrate used in the present invention may also comprise titanium and/or titanium alloys, zinc and/or zinc alloys, and/or nickel and/or nickel alloys.
  • the substrate may comprise a portion of a vehicle such as a vehicular body (e.g., without limitation, door, body panel, trunk deck lid, roof panel, hood, roof and/or stringers, rivets, landing gear components, and/or skins used on an aircraft) and/or a vehicular frame.
  • a vehicular body e.g., without limitation, door, body panel, trunk deck lid, roof panel, hood, roof and/or stringers, rivets, landing gear components, and/or skins used on an aircraft
  • vehicle or variations thereof includes, but is not limited to, civilian, commercial and military aircraft, and/or land vehicles such as cars, motorcycles, and/or trucks.
  • the conversion composition of the present invention may comprise a conversion composition comprising trivalent chromium.
  • the conversion composition may further comprise an anion that may be suitable for forming a salt with a trivalent chromium cation, including for example a sulfate, a nitrate, an acetate, a carbonate, a hydroxide, or combinations thereof.
  • the trivalent chromium salt may be present in the conversion composition in an amount of at least 0.001 g/L, such as at least 0.1 g/L, such as at least 0.5 g/L, and in some instances, no more than 20 g/L, such as no more than 10 g/L, such as no more than 5 g/L.
  • the trivalent chromium salt may be present in the conversion composition in an amount of 0.001 g/L to 20 g/L, such as 0.1 g/L to 10 g/L, such as 0.5 g/L to 5 g/L.
  • the conversion composition also may comprise a metal such as a Group I and/or a Group II metal.
  • a metal such as a Group I and/or a Group II metal.
  • the Group I and/or Group II metal may be present as a metal salt.
  • the anion forming the salt with a Group I and/or Group II cation may comprise, for example, a halogen, a nitrate, a sulfate, an acetate, a phosphate, a silicate (e.g., orthosilicates and metasilicates), a carbonate, an hydroxide, and the like.
  • the conversion composition also may comprise at least one coinhibitor.
  • the coinhibitor may comprise a Group IIA metal, a transition metal, a lanthanide series metal, an azole, or combinations thereof.
  • the lanthanide series may, for example, comprise cerium, praseodymium, terbium, or combinations thereof;
  • the Group IIA metal may comprise magnesium;
  • the transition metal may comprise a Group IIIB metal such as yttrium, scandium, or combinations thereof, a Group IVB metal such as zirconium, titanium, hafnium, or combinations thereof, a Group VB metal such as vanadium, a Group VIB metal such as molybdenum, a Group VIIB metal such as manganese; and/or a Group IIB metal such as zinc.
  • “coinhibitor” refers to a metal or other compound present in the conversion composition in addition to the trivalent chromium to reduce pitting on the substrate surface (i.e., an improvement in corrosion performance).
  • the conversion composition may further comprise an anion that may be suitable for forming a salt with the conversion composition metal cations of the coinhibitor(s), such as a halogen, a nitrate, a sulfate, a phosphate, a silicate (e.g., orthosilicates and metasilicates), a carbonate, an acetate, a hydroxide, and the like.
  • an anion that may be suitable for forming a salt with the conversion composition metal cations of the coinhibitor(s), such as a halogen, a nitrate, a sulfate, a phosphate, a silicate (e.g., orthosilicates and metasilicates), a carbonate, an acetate, a hydroxide, and the like.
  • the salt of the coinhibitor of the conversion composition may be present in the conversion composition in an amount of at least 0.001 g/L, such as at least 0.1 g/L, such as at least 0.5 g/L, and in some instances, no more than 20 g/L, such as no more than 10 g/L, such as no more than 5 g/L.
  • the salt of the coinhibitor of the conversion composition may be present in the conversion composition in an amount of 0.001 g/L to 20 g/L, such as 0.1 g/L to 10 g/L, such as 0.5 g/L to 5 g/L.
  • the conversion composition may exclude hexavalent chromium or compounds that include hexavalent chromium.
  • Non-limiting examples of such materials include chromic acid, chromium trioxide, chromic acid anhydride, dichromate salts, such as ammonium dichromate, sodium dichromate, potassium dichromate, and calcium, barium, magnesium, zinc, cadmium, and strontium dichromate.
  • hexavalent chromium in any form, such as, but not limited to, the hexavalent chromium-containing compounds listed above.
  • the conversion compositions and/or coatings or layers, respectively, deposited from the same may be substantially free, may be essentially free, and/or may be completely free of one or more of any of the elements or compounds listed in the preceding paragraph.
  • a conversion composition and/or coating or layer, respectively, formed from the same that is substantially free of hexavalent chromium or derivatives thereof means that hexavalent chromium or derivatives thereof are not intentionally added, but may be present in trace amounts, such as because of impurities or unavoidable contamination from the environment.
  • the amount of material is so small that it does not affect the properties of the conversion composition; in the case of hexavalent chromium, this may further include that the element or compounds thereof are not present in the conversion compositions and/or coatings or layers, respectively, formed from the same in such a level that it causes a burden on the environment.
  • the term “substantially free” means that the conversion compositions and/or coating or layers, respectively, formed from the same contain less than 10 ppm of any or all of the elements or compounds listed in the preceding paragraph, based on total weight of the composition or the layer, respectively, if any at all.
  • the term “essentially free” means that the conversion compositions and/or coatings or layers, respectively, formed from the same contain less than 1 ppm of any or all of the elements or compounds listed in the preceding paragraph, if any at all.
  • the term “completely free” means that the conversion compositions and/or coatings or layers, respectively, formed from the same contain less than 1 ppb of any or all of the elements or compounds listed in the preceding paragraph, if any at all.
  • the pH of the conversion composition may, in some instances, be less than 7, such as less than 5, such as 1.5 to 6.9, such as 2.0 to 6.0, such as 2.5 to 4.5.
  • the pH may be adjusted using, for example, any acid and/or base as is necessary.
  • the pH of the conversion composition may be maintained through the inclusion of an acidic material, including water soluble and/or water dispersible acids, such as nitric acid, sulfuric acid, and/or phosphoric acid.
  • the pH of the composition may be maintained through the inclusion of a basic material, including water soluble and/or water dispersible bases, such as sodium hydroxide, sodium carbonate, potassium carbonate, potassium hydroxide, ammonium hydroxide, ammonia, and/or amines such as triethylamine, methylethyl amine, or mixtures thereof.
  • the conversion composition may comprise an aqueous medium and may optionally contain other materials such as nonionic surfactants and auxiliaries conventionally used in the art of conversion compositions.
  • water dispersible organic solvents for example, alcohols with up to about 8 carbon atoms such as methanol, isopropanol, and the like, may be present; or glycol ethers such as the monoalkyl ethers of ethylene glycol, diethylene glycol, or propylene glycol, and the like.
  • water dispersible organic solvents are typically used in amounts up to about ten percent by volume, based on the total volume of aqueous medium.
  • thickeners such as cellulosic, silicated, or acrylic thickeners may be present.
  • thickeners are typically used in amounts of at least 0.00001 % by weight, such as at least 0.5% by weight, and in some instances, no more than 5% by weight, such as no more than 1% by weight.
  • thickeners are typically used in amounts of 0.00001% to 5% by weight, such as 0.5% to 1% by weight.
  • Other optional materials include surfactants that function as defoamers or substrate wetting agents.
  • Anionic, cationic, amphoteric, and/or nonionic surfactants may be used.
  • Defoaming surfactants may optionally be present at levels up to 1 weight percent, such as up to 0.1 percent by weight, and wetting agents are typically present at levels up to 2 percent, such as up to 0.5 percent by weight, based on the total weight of the conversion composition.
  • the conversion composition may comprise a carrier, often an aqueous medium, so that the composition is in the form of a solution or dispersion of the trivalent chromium cation and optionally other metal ions and/or coinhibitors in the carrier.
  • the solution or dispersion may be brought into contact with the substrate by any of a variety of known techniques, such as dipping or immersion, spraying, intermittent spraying, dipping followed by spraying, spraying followed by dipping, brushing, or roll-coating.
  • the solution or dispersion when applied to the metal substrate, is at a temperature ranging from 40°F to 160°F , such as 60°F to 110°F , such as 70°F to 90°F.
  • the conversion process may be carried out at ambient conditions.
  • the contact time is often from 1 second to 30 minutes, such as 30 seconds to 15 minutes, such as 4 minutes to 10 minutes.
  • ambient conditions refer to room temperature and humidity conditions or temperature and humidity conditions that are typically found in the area in which the coating composition is being applied to a substrate, e.g., at 10°C to 40°C and 5% to 80% relative humidity, while slightly thermal conditions are temperatures that are slightly above ambient temperature (e.g., > 40°C and less than 100°C at 5% to 80% relative humidity)
  • the substrate optionally may be air dried at room temperature or may be dried with hot air, such as slightly thermal air, for example, by using an air knife, by flashing off the water by brief exposure of the substrate to a high temperature (i.e., a temperature greater than ambient), such as by drying the substrate in an oven at 15°C to 100°C, such as 20°C to 90°C, or in a heater assembly using, for example, infrared heat, such as for 10 minutes at 70°C, or by passing the substrate between squeegee rolls.
  • a high temperature i.e., a temperature greater than ambient
  • the substrate optionally may be rinsed with tap water, deionized water, reverse osmosis (RO) water and/or an aqueous solution of rinsing agents in order to remove any residue and then optionally may be dried, for example air dried or dried with hot air as described in the preceding sentence.
  • RO reverse osmosis
  • At least a portion of the substrate surface may be cleaned and/or deoxidized prior to contacting at least a portion of the substrate surface with the conversion composition described above, in order to remove grease, dirt, and/or other extraneous matter.
  • At least a portion of the surface of the substrate may be cleaned by physical and/or chemical means, such as mechanically abrading the surface and/or cleaning/degreasing the surface with alkaline or acidic cleaning compositions.
  • Such cleaners are often preceded or followed by a water rinse, such as with tap water, distilled water, RO water, or combinations thereof.
  • cleaning compositions” or “cleaner compositions” included in the treatment systems and methods of the present invention may have deoxidizing functionality in addition to degreasing characteristics.
  • the cleaning composition may be alkaline and may have a pH greater than 7, such as greater than 9, such as greater than 11.
  • the pH of the cleaning composition may be 7 to 13, such as 9 to 12.7.
  • the cleaning composition may be acidic and may have a pH less than 7, such as less than 6, such as less than 5.5.
  • the pH of the cleaning composition may be 0.5 to 6, such as 1.5 to 4.5.
  • the cleaning composition may include commercially available alkaline cleaners, including ChemkleenTM 163, 177, 611L, 490MX, 2010LP, and 181ALP, Ultrax 32, Ultrax 97, and Ultrax 94D, each of which are commercially available from PPG Industries, Inc. (Cleveland, OH), and any of the DFM Series, RECC 1001, and 88X1002 cleaners (commercially available from PRC -DeSoto International, Sylmar, CA), and any of the Turco or Bonderite/Ridolene series of cleaners (commercially available from Henkel Technologies, Madison Heights, MI), and any of the SOCOCLEAN series of cleaners (commercially available from Socomore).
  • alkaline cleaners including ChemkleenTM 163, 177, 611L, 490MX, 2010LP, and 181ALP, Ultrax 32, Ultrax 97, and Ultrax 94D, each of which are commercially available from PPG Industries, Inc. (Cleveland, OH), and any of
  • the cleaning composition of the present invention may comprise a carrier such as water such that the cleaning composition is in the form of a solution or dispersion.
  • the solution or dispersion may be brought into contact with the substrate by any of a variety of techniques, including but not limited to dip immersion, spraying, swabbing, or spreading using a brush, roller, or the like.
  • the cleaning composition may be applied using an electrolytic-coating system.
  • the dwell time in which the cleaning composition remains in contact with the metal substrate may vary from a few seconds to multiple hours, for example less than 30 minutes or three minutes or less.
  • the immersion times may vary from a few seconds to multiple hours, for example less than 30 minutes or three minutes or less, such as 2 seconds.
  • the cleaning composition When the cleaning composition is applied to the metal substrate using a spray application, the composition may be brought into contact with at least a portion of the substrate using conventional spray application methods.
  • the dwell time in which the cleaning composition remains in contact with the metal substrate may vary from a few seconds to multiple hours, for example less than 30 minutes or three minutes or less, such as 2 seconds.
  • the metal substrate may optionally be air dried, and then rinsed with tap water, RO water, and/or distilled/de-ionized water. Alternately, after contacting the metal substrate with the composition, the metal substrate may be rinsed with tap water, RO water, and/or distilled/de-ionized water, and then subsequently air dried (if desired). However, the substrate need not be dried, and in some instances, drying is omitted. Additionally, as noted above, the substrate need not be rinsed, and the metal substrate may then be further coated with conversion coatings, primers and/or topcoats to achieve a substrate with a finished coating. Accordingly, in some instances this subsequent rinse may be omitted.
  • the cleaning composition may be applied to a metal substrate for 1 to 10 minutes (for example, 3 to 5 minutes), and the surface of the metal substrate may be kept wet by reapplying the cleaning composition. Then, the composition is optionally allowed to dry, for example in the absence of heat greater than room temperature, for 5 to 10 minutes (for example, 7 minutes) after the last application of the composition. However, the substrate does not need to be allowed to dry, and in some instances, drying is omitted.
  • a solvent e.g., alcohol
  • the metal substrate optionally may be conditioned prior to contacting the metal substrate with the cleaning composition described above.
  • conditioning refers to the surface modification of the substrate prior to subsequent processing.
  • Such surface modification can include various operations, including, but not limited to cleaning (to remove impurities and/or dirt from the surface), deoxidizing, and/or application of a solution or coating, as is known in the art.
  • Conditioning may have one or more benefits, such as the generation of a more uniform starting metal surface, improved adhesion to a subsequent coating on the pre-treated substrate, and/or modification of the starting surface in such a way as to facilitate the deposition of a subsequent composition.
  • the metal substrate may be pre-treated by solvent wiping the metal prior to applying the composition to the metal substrate.
  • suitable solvents include methyl ethyl ketone (MEK), methyl propyl ketone (MPK), acetone, and the like.
  • the metal substrate optionally may be prepared by first solvent treating the metal substrate prior to contacting the metal substrate with the cleaning composition.
  • solvent treating refers to rinsing, wiping, spraying, or immersing the substrate in a solvent that assists in the removal of inks, oils, etc. that may be on the metal surface.
  • the metal substrate may be prepared by degreasing the metal substrate using conventional degreasing methods prior to contacting the metal substrate with the cleaning composition.
  • Additional optional procedures for preparing the metal substrate include the use of a surface brightener, such as an acid pickle or light acid etch, or a smut remover.
  • a surface brightener such as an acid pickle or light acid etch, or a smut remover.
  • the metal substrate may be rinsed with either tap water, RO water, and/or distilled/de-ionized water between each of the conversion steps and may be rinsed well with distilled/de-ionized water and/or alcohol after contact with the composition according to the present invention.
  • tap water RO water
  • distilled/de-ionized water between each of the conversion steps and may be rinsed well with distilled/de-ionized water and/or alcohol after contact with the composition according to the present invention.
  • some of the above described pre-treatment procedures and rinses may not be necessary prior to or after application of the cleaning composition.
  • the cleaned substrate surface may be deoxidized, mechanically and/or chemically.
  • the term “deoxidize” means removal of the oxide layer found on the surface of the substrate in order to promote uniform deposition of the conversion composition (described below), as well as to promote the adhesion of the conversion composition coating to the substrate surface.
  • Suitable deoxidizers will be familiar to those skilled in the art.
  • a typical mechanical deoxidizer may be uniform roughening of the substrate surface, such as by using a scouring or cleaning pad.
  • Typical chemical deoxidizers include, for example, acid-based deoxidizers such as phosphoric acid, nitric acid, fluoroboric acid, sulfuric acid, chromic acid, hydrofluoric acid, and ammonium bifluoride, or Amchem 7/17 deoxidizers (available from Henkel Technologies, Madison Heights, MI), any of the OAKITE series of deoxidizers (commercially available from BASF), any of the TURCO series of deoxidizers (commercially available from Henkel), any of the Socosurf series of deoxidizers (commercially available from Socomore), or combinations thereof.
  • acid-based deoxidizers such as phosphoric acid, nitric acid, fluoroboric acid, sulfuric acid, chromic acid, hydrofluoric acid, and ammonium bifluoride, or Amchem 7/17 deoxidizers (available from Henkel Technologies, Madison Heights, MI), any of the OAKITE series of deoxidizers (commercially available from BASF), any of the TURCO series
  • the chemical deoxidizer comprises a carrier, often an aqueous medium, so that the deoxidizer may be in the form of a solution or dispersion in the carrier, in which case the solution or dispersion may be brought into contact with the substrate by any of a variety of known techniques, such as dipping or immersion, spraying, intermittent spraying, dipping followed by spraying, spraying followed by dipping, brushing, or roll-coating.
  • the skilled artisan will select a temperature range of the solution or dispersion, when applied to the metal substrate, based on etch rates, for example, at a temperature ranging from 50°F to 150°F (10°C to 66°C), such as from 70°F to 130°F (21°C to 54°C), such as from 80°F to 120°F (27°C to 49°C).
  • the contact time may be from 30 seconds to 20 minutes, such as 1 minute to 15 minutes, such as 90 seconds to 12 minutes, such as 3 minutes to 9 minutes.
  • the system of the present invention may further comprise a sealing composition.
  • the sealing composition may comprise an ammonium-containing compound.
  • the ammonium-containing compound may be in the form of an ammonium salt.
  • the sealing composition may further comprise an anion that may be suitable for forming a salt with the ammonium cation, including for example, a sulfate, a nitrate, an acetate, a carbonate, a hydroxide, a phosphate, or combinations thereof.
  • ammonium- containing compounds include basic salts of ammonium, ammonium zirconium carbonate (AZC), ammonium acetate, ammonium zirconium sulfate, ammonium zirconium lactate, ammonium zirconium glycolate. and the like.
  • the ammonium of the ammonium-containing compound may be present in the sealing composition in an amount of at least 100 ppm based on total weight of the sealing composition, such as at least 120 ppm, and may be present in the sealing composition in an amount of no more than 1,500 ppm based on total weight of the sealing composition, such as no more than 1,000 ppm.
  • the ammonium may be present in the sealing composition in an amount of 100 ppm to 1,500 ppm based on total weight of the sealing composition, such as 120 ppm to 1,000 ppm.
  • the sealing composition may further comprise a Group IVB metal.
  • the Group IVB metal may, for example, be titanium, zirconium, hafnium or combinations thereof.
  • the Group IVB metal may be introduced to the sealing composition as a compound such as an inorganic or organic salt.
  • Suitable compounds of zirconium include, but are not limited to, hexafluorozirconic acid, alkali metal and ammonium salts thereof, ammonium zirconium carbonate, zirconyl nitrate, zirconyl sulfate, zirconium carboxylates and zirconium hydroxy carboxylates, such as zirconium acetate, zirconium oxalate, ammonium zirconium glycolate, ammonium zirconium lactate, ammonium zirconium citrate and mixtures thereof.
  • a suitable compound of hafnium includes, but is not limited to, hafnium nitrate.
  • a suitable compound of titanium includes, but is not limited to, fluorotitanic acid and its salt
  • Nonlimiting examples of anions suitable for forming a salt with the Group IVB metal cation include carbonates, hydroxides, nitrates, halogens, sulfates, phosphates and silicates (e.g., orthosilicates and metasilicates) such that the metal salt may comprise a carbonate, a hydroxide, a nitrate, a halide, a sulfate, a phosphate, a silicate (e.g., orthosilicate or metasilicate), a permanganate, a chromate, a vanadate, a molybdate, and/or a perchlorate.
  • anions suitable for forming a salt with the Group IVB metal cation include carbonates, hydroxides, nitrates, halogens, sulfates, phosphates and silicates (e.g., orthosilicates and metasilicates) such that the metal salt may comprise a
  • the Group IVB metal may be present in the sealing composition in an amount of at least 250 ppm based on total weight of the sealing composition, such as at least 500 ppm, and may be present in the sealing composition in an amount of no more than 3,800 ppm based on total weight of the sealing composition, such as no more than 2,600 ppm.
  • the Group IVB metal may be present in the sealing composition in an amount of 250 ppm to 3,800 ppm based on total weight of the sealing composition, such 500 ppm to 2,600 ppm.
  • the sealing composition may exclude chromium or chromium-containing compounds.
  • chromium-containing compound refers to materials that include hexavalent chromium. Non-limiting examples of such materials include chromic acid, chromium trioxide, chromic acid anhydride, dichromate salts, such as ammonium dichromate, sodium dichromate, potassium dichromate, and calcium, barium, magnesium, zinc, cadmium, and strontium dichromate.
  • chromium in any form, such as, but not limited to, the hexavalent chromium-containing compounds listed above.
  • the present sealing compositions and/or coatings or layers, respectively, deposited from the same may be substantially free, may be essentially free, and/or may be completely free of one or more of any of the elements or compounds listed in the preceding paragraph.
  • a sealing composition and/or coating or layer, respectively, formed from the same that is substantially free of chromium or derivatives thereof means that chromium or derivatives thereof are not intentionally added, but may be present in trace amounts, such as because of impurities or unavoidable contamination from the environment.
  • the amount of material is so small that it does not affect the properties of the sealing composition; in the case of chromium, this may further include that the element or compounds thereof are not present in the sealing compositions and/or coatings or layers, respectively, formed from the same in such a level that it causes a burden on the environment.
  • the term “substantially free” means that the sealing compositions and/or coating or layers, respectively, formed from the same contain less than 10 ppm of any or all of the elements or compounds listed in the preceding paragraph, based on total weight of the composition or the layer, respectively, if any at all.
  • the term “essentially free” means that the sealing compositions and/or coatings or layers, respectively, formed from the same contain less than 1 ppm of any or all of the elements or compounds listed in the preceding paragraph, if any at all.
  • the term “completely free” means that the sealing compositions and/or coatings or layers, respectively, formed from the same contain less than 1 ppb of any or all of the elements or compounds listed in the preceding paragraph, if any at all.
  • the sealing composition may, in some instances, exclude phosphate ions or phosphate-containing compounds and/or the formation of sludge, such as aluminum phosphate, iron phosphate, and/or zinc phosphate, formed in the case of using a treating agent based on zinc phosphate.
  • phosphate-containing compounds include compounds containing the element phosphorous such as ortho phosphate, pyrophosphate, metaphosphate, tripolyphosphate, organophosphonates, and the like, and can include, but are not limited to, monovalent, divalent, or trivalent cations such as: sodium, potassium, calcium, zinc, nickel, manganese, aluminum and/or iron.
  • a composition and/or a layer or coating comprising the same is substantially free, essentially free, or completely free of phosphate, this includes phosphate ions or compounds containing phosphate in any form.
  • sealing composition and/or layers deposited from the same may be substantially free, or in some cases may be essentially free, or in some cases may be completely free, of one or more of any of the ions or compounds listed in the preceding paragraph.
  • a sealing composition and/or layers deposited from the same that is substantially free of phosphate means that phosphate ions or compounds containing phosphate are not intentionally added, but may be present in trace amounts, such as because of impurities or unavoidable contamination from the environment. In other words, the amount of material is so small that it does not affect the properties of the composition; this may further include that phosphate is not present in the sealing compositions and/or layers deposited from the same in such a level that they cause a burden on the environment.
  • substantially free means that the sealing compositions and/or layers deposited from the same contain less than 5 ppm of any or all of the phosphate anions or compounds listed in the preceding paragraph, based on total weight of the composition or the layer, respectively, if any at all.
  • essentially free means that the sealing compositions and/or layers comprising the same contain less than 1 ppm of any or all of the phosphate anions or compounds listed in the preceding paragraph.
  • completely free means that the sealing compositions and/or layers comprising the same contain less than 1 ppb of any or all of the phosphate anions or compounds listed in the preceding paragraph, if any at all.
  • the sealing composition may optionally further contain an indicator compound, so named because it indicates, for example, the presence of a chemical species, such as a metal ion, the pH of a composition, and the like.
  • an “indicator”, “indicator compound”, and like terms as used herein refer to a compound that changes color in response to some external stimulus, parameter, or condition, such as the presence of a metal ion, or in response to a specific pH or range of pHs.
  • the indicator compound used according to the present invention can be any indicator known in the art that indicates the presence of a species, a particular pH, and the like.
  • a suitable indicator may be one that changes color after forming a metal ion complex with a particular metal ion.
  • the metal ion indicator is generally a highly conjugated organic compound.
  • the indicator compound can be one in which the color changes upon change of the pH; for example, the compound may be one color at an acidic or neutral pH and change color in an alkaline pH, or vice versa.
  • Such indicators are well known and widely commercially available.
  • An indicator that “changes color upon transition from a first pH to a second pH” i.e., from a first pH to a second pH that is more or less acidic or alkaline) therefore has a first color (or is colorless) when exposed to a first pH and changes to a second color (or goes from colorless to colored) upon transition to a second pH (i.e., one that is either more or less acidic or alkaline than the first pH).
  • an indicator that “changes color upon transition to a more alkaline pH (or less acidic pH) goes from a first color/colorless to a second color/color when the pH transitions from acidic/neutral to alkaline.
  • an indicator that “changes color upon transition to a more acidic pH (or less alkaline pH) goes from a first color/colorless to a second color/color when the pH transitions from alkaline/neutral to acidic.
  • Non-limiting examples of such indicator compounds include methyl orange, xylenol orange, catechol violet, bromophenol blue, green and purple, eriochrome black T, Celestine blue, hematoxylin, calmagite, gallocyanine, and combinations thereof.
  • the indicator compound may comprise an organic indicator compound that is a metal ion indicator.
  • Nonlimiting examples of indicator compounds include those found in Table 1. Fluorescent indicators, which will emit light in certain conditions, can also be used according to the present invention, although the use of a fluorescent indicator also may be specifically excluded. That is, alternatively, conjugated compounds that exhibit fluorescence are specifically excluded.
  • fluorescent indicator and like terms refer to compounds, molecules, pigments, and/or dyes that will fluoresce or otherwise exhibit color upon exposure to ultraviolet or visible light.
  • fluoresce will be understood as emitting light following absorption of shorter wavelength light or other electromagnetic radiation.
  • indicators often referred to as “tags,” include acridine, anthraquinone, coumarin, diphenylmethane, diphenylnaphthylmethane, quinoline, stilbene, triphenylmethane, anthracine and/or molecules containing any of these moieties and/or derivatives of any of these such as rhodamines, phenanthridines, oxazines, fluorones, cyanines and/or acridines.
  • the conjugated compound useful as indicator may for example comprise catechol violet, as shown in Table 1.
  • Catechol violet (CV) is a sulfone phthalein dye made from condensing two moles of pyrocatechol with one mole of o- sulfobenzoic acid anhydride. It has been found that CV has indicator properties and when incorporated into compositions having metal ions, it forms complexes, making it useful as a complexiometric reagent. As the composition containing the CV chelates metal ions coming from the metal substrate (i.e., those having bi- or higher valence), a generally blue to blue-violet color is observed.
  • Xylenol orange as shown in Table 1 may likewise be employed in the compositions according to the present invention. It has been found that xylenol orange has metal ion (i.e., those having bi- or higher valence) indicator properties and when incorporated into compositions having metal ions, it forms complexes, making it useful as a complexiometric reagent. As the composition containing the xylenol orange chelates metal ions, a solution of xylenol orange turns from red to a generally blue color.
  • the indicator compound may be present in the sealing composition in an amount of at least 0.01 g/ 1000 g sealing composition, such as at least 0.05 g/1000 g sealing composition, and in some instances, no more than 3 g/1000 g sealing composition, such as no more than 0.3g/1000 g sealing composition.
  • the indicator compound may be present in the sealing composition in an amount of 0.01 g/1000 g sealing composition to 3 g/1000 g sealing composition, such as 0.05 g/1000 g sealing composition to 0.3 g/1000 g sealing composition.
  • the indicator compound changing color in response to a certain external stimulus provides a benefit when using the sealing composition in that it can serve, for example, as a visual indication that a substrate has been treated with the composition.
  • a sealing composition comprising an indicator that changes color when exposed to a metal ion that is present in the substrate will change color upon complexing with metal ions in that substrate; this allows the user to see that the substrate has been contacted with the composition.
  • Similar benefits can be realized by depositing an alkaline or acid layer on a substrate and contacting the substrate with a composition of the present invention that changes color when exposed to an alkaline or acidic pH.
  • the sealing composition may comprise an aqueous medium and optionally may contain other materials such as at least one organic solvent.
  • suitable such solvents include propylene glycol, ethylene glycol, glycerol, low molecular weight alcohols, and the like.
  • the organic solvent may be present in the sealing composition in an amount of at least 1 g solvent per liter of sealing composition, such as at least about 2 g solvent per liter of sealing solution, and in some instances, may be present in an amount of no more than 40 g solvent per liter of sealing composition, such as no more than 20 g solvent per liter of sealing solution.
  • the organic solvent may be present in the sealing composition, if at all, in an amount of 1 g solvent per liter of sealing composition to 40 g solvent per liter of sealing composition, such as 2 g solvent per liter of sealing composition to 20 g solvent per liter of sealing composition.
  • the pH of the sealing composition may be at least 5, such as at least 6, such as at least 7, and in some instances may be no higher than 11, such as no higher than 10, such as no higher than 9.
  • the pH of the sealing composition may be 5 to 11, such as 6 to 10, such as 7 to 9.
  • the pH of the sealing composition may be adjusted using, for example, any acid and/or base as is necessary.
  • the pH of the sealing composition may be maintained through the inclusion of an acidic material, including carbon dioxide, water soluble and/or water dispersible acids, such as nitric acid, sulfuric acid, and/or phosphoric acid.
  • the pH of the sealing composition may be maintained through the inclusion of a basic material, including water soluble and/or water dispersible bases, including carbonates such as Group I carbonates, Group II carbonates, hydroxides such as sodium hydroxide, potassium hydroxide, or ammonium hydroxide, ammonia, and/or amines such as triethylamine, methylethyl amine, or mixtures thereof.
  • a basic material including water soluble and/or water dispersible bases, including carbonates such as Group I carbonates, Group II carbonates, hydroxides such as sodium hydroxide, potassium hydroxide, or ammonium hydroxide, ammonia, and/or amines such as triethylamine, methylethyl amine, or mixtures thereof.
  • the sealing composition may comprise a carrier, often an aqueous medium, so that the composition is in the form of a solution or dispersion of the ammonium-containing compound in the carrier.
  • the solution or dispersion may be brought into contact with the substrate by any of a variety of known techniques, such as dipping or immersion, spraying, intermittent spraying, dipping followed by spraying, spraying followed by dipping, brushing, or roll-coating.
  • the solution or dispersion when applied to the metal substrate may be at a temperature ranging from 40°F to about 160°F, such as 60°F to 110°F.
  • the process of contacting the metal substrate with the sealing composition may be carried out at ambient or room temperature.
  • the contact time is often from about 1 second to about 15 minutes, such as about 5 seconds to about 2 minutes.
  • the substrate optionally may be air dried at room temperature or may be dried with hot air, for example, by using an air knife, by flashing off the water by brief exposure of the substrate to a high temperature, such as by drying the substrate in an oven at 15°C to 100°C, such as 20°C to 90°C, or in a heater assembly using, for example, infrared heat, such as for 10 minutes at 70°C, or by passing the substrate between squeegee rolls.
  • the substrate surface may be partially, or in some instances, completely dried prior to any subsequent contact of the substrate surface with any water, solutions, compositions, or the like.
  • “completely dry” or “completely dried” means there is no moisture on the substrate surface visible to the human eye.
  • the substrate optionally is not rinsed or contacted with any aqueous solutions prior to contacting at least a portion of the substrate surface with subsequent treatment compositions to form films, layers, and/or coatings thereon (described below).
  • the substrate optionally may be contacted with tap water, deionized water, RO water and/or any aqueous solution known to those of skill in the art of substrate treatment, wherein such water or aqueous solution may be at a temperature of room temperature (60°F) to 212°F
  • the substrate then optionally may be dried, for example air dried or dried with hot air as described in the preceding paragraph such that the substrate surface may be partially, or in some instances, completely dried prior to any subsequent contact of the substrate surface with any water, solutions, compositions, or the like.
  • a method of treating a substrate comprising, or consisting essentially of, or consisting of, contacting at least a portion of the substrate with a conversion composition comprising, or in some instances consisting of, or in some instances consisting essentially of, trivalent chromium; and contacting the surface contacted with the conversion composition with a sealing composition comprising, or consisting essentially of, or consisting of, an ammonium-containing compound.
  • a coating composition comprising a film-forming resin may be deposited onto at least a portion of the surface of the substrate that has been contacted with the sealing composition.
  • any suitable technique may be used to deposit such a coating composition onto the substrate, including, for example, brushing, dipping, flow coating, spraying and the like.
  • depositing of a coating composition may comprise an electrocoating step wherein an electrodepositable composition is deposited onto a metal substrate by electrodeposition.
  • depositing of a coating composition may comprise a powder coating step.
  • the coating composition may be a liquid coating composition.
  • the coating composition may comprise a thermosetting film-forming resin or a thermoplastic film-forming resin.
  • film-forming resin refers to resins that can form a self-supporting continuous film on at least a horizontal surface of a substrate upon removal of any diluents or carriers present in the composition or upon curing at ambient or elevated temperature.
  • Conventional film-forming resins that may be used include, without limitation, those typically used in automotive OEM coating compositions, automotive refmish coating compositions, industrial coating compositions, architectural coating compositions, coil coating compositions, and aerospace coating compositions, among others.
  • thermosetting refers to resins that “set” irreversibly upon curing or crosslinking, wherein the polymer chains of the polymeric components are joined together by covalent bonds. This property is usually associated with a cross-linking reaction of the composition constituents often induced, for example, by heat or radiation. Curing or crosslinking reactions also may be carried out under ambient conditions. Once cured or crosslinked, a thermosetting resin will not melt upon the application of heat and is insoluble in solvents.
  • thermoplastic refers to resins that comprise polymeric components that are not joined by covalent bonds and thereby can undergo liquid flow upon heating and are soluble in solvents.
  • an electrodepositable coating composition comprising a water-dispersible, ionic salt group-containing film-forming resin that may be deposited onto the substrate by an electrocoating step wherein the electrodepositable coating composition is deposited onto the metal substrate by electrodeposition.
  • the ionic salt group-containing film-forming polymer may comprise a cationic salt group containing film-forming polymer for use in a cationic electrodepositable coating composition.
  • the term “cationic salt group-containing film-forming polymer” refers to polymers that include at least partially neutralized cationic groups, such as sulfonium groups and ammonium groups, that impart a positive charge.
  • the cationic salt group-containing film-forming polymer may comprise active hydrogen functional groups, including, for example, hydroxyl groups, primary or secondary amine groups, and thiol groups.
  • Cationic salt group- containing film-forming polymers that comprise active hydrogen functional groups may be referred to as active hydrogen-containing, cationic salt group-containing film-forming polymers.
  • Examples of polymers that are suitable for use as the cationic salt group-containing film-forming polymer include, but are not limited to, alkyd polymers, acrylics, polyepoxides, polyamides, polyurethanes, polyureas, polyethers, and polyesters, among others.
  • the cationic salt group-containing film-forming polymer may be present in the cationic electrodepositable coating composition in an amount of 40% to 90% by weight, such as 50% to 80% by weight, such as 60% to 75% by weight, based on the total weight of the resin solids of the electrodepositable coating composition.
  • the “resin solids” include the ionic salt group-containing film-forming polymer, curing agent, and any additional water- dispersible non-pigmented component s) present in the electrodepositable coating composition.
  • the ionic salt group containing film-forming polymer may comprise an anionic salt group containing film-forming polymer for use in an anionic electrodepositable coating composition.
  • anionic salt group containing film-forming polymer refers to an anionic polymer comprising at least partially neutralized anionic functional groups, such as carboxylic acid and phosphoric acid groups that impart a negative charge.
  • the anionic salt group-containing film-forming polymer may comprise active hydrogen functional groups.
  • Anionic salt group-containing film-forming polymers that comprise active hydrogen functional groups may be referred to as active hydrogen-containing, anionic salt group- containing film-forming polymers.
  • the anionic salt group-containing film-forming polymer may comprise base- solubilized, carboxylic acid group-containing film-forming polymers such as the reaction product or adduct of a drying oil or semi -drying fatty acid ester with a dicarboxylic acid or anhydride; and the reaction product of a fatty acid ester, unsaturated acid or anhydride and any additional unsaturated modifying materials which are further reacted with polyol. Also suitable are the at least partially neutralized interpolymers of hydroxy-alkyl esters of unsaturated carboxylic acids, unsaturated carboxylic acid and at least one other ethyl enically unsaturated monomer.
  • Still another suitable anionic electrodepositable resin comprises an alkyd-aminoplast vehicle, i.e., a vehicle containing an alkyd resin and an amine-aldehyde resin.
  • Another suitable anionic electrodepositable resin composition comprises mixed esters of a resinous polyol.
  • Other acid functional polymers may also be used such as phosphatized polyepoxide or phosphatized acrylic polymers. Exemplary phosphatized polyepoxides are disclosed in U.S. Patent Application Publication No. 2009-0045071 at [0004]-[0015] and U.S. Patent Application Serial No. 13/232,093 at [0014]-[0040], the cited portions of which being incorporated herein by reference.
  • the anionic salt group-containing film-forming polymer may be present in the anionic electrodepositable coating composition in an amount 50% to 90%, such as 55% to 80%, such as 60% to 75%, based on the total weight of the resin solids of the electrodepositable coating composition.
  • the electrodepositable coating composition may further comprise a curing agent.
  • the curing agent may react with the reactive groups, such as active hydrogen groups, of the ionic salt group-containing film-forming polymer to effectuate cure of the coating composition to form a coating.
  • suitable curing agents are at least partially blocked polyisocyanates, aminoplast resins and phenoplast resins, such as phenolformaldehyde condensates including allyl ether derivatives thereof.
  • the curing agent may be present in the cationic electrodepositable coating composition in an amount of 10% to 60% by weight, such as 20% to 50% by weight, such as 25% to 40% by weight, based on the total weight of the resin solids of the electrodepositable coating composition.
  • the curing agent may be present in the anionic electrodepositable coating composition in an amount of 10% to 50% by weight, such as 20% to 45% by weight, such as 25% to 40% by weight, based on the total weight of the resin solids of the electrodepositable coating composition.
  • the electrodepositable coating composition may further comprise other optional ingredients, such as a pigment composition and, if desired, various additives such as fillers, plasticizers, anti-oxidants, biocides, UV light absorbers and stabilizers, hindered amine light stabilizers, defoamers, fungicides, dispersing aids, flow control agents, surfactants, wetting agents, or combinations thereof.
  • additives such as fillers, plasticizers, anti-oxidants, biocides, UV light absorbers and stabilizers, hindered amine light stabilizers, defoamers, fungicides, dispersing aids, flow control agents, surfactants, wetting agents, or combinations thereof.
  • the electrodepositable coating composition may comprise water and/or one or more organic solvent(s).
  • Water can for example be present in amounts of 40% to 90% by weight, such as 50% to 75% by weight, based on total weight of the electrodepositable coating composition.
  • the organic solvents may typically be present in an amount of less than 10% by weight, such as less than 5% by weight, based on total weight of the electrodepositable coating composition.
  • the electrodepositable coating composition may in particular be provided in the form of an aqueous dispersion.
  • the total solids content of the electrodepositable coating composition may be from 1% to 50% by weight, such as 5% to 40% by weight, such as 5% to 20% by weight, based on the total weight of the electrodepositable coating composition.
  • total solids refers to the non-volatile content of the electrodepositable coating composition, i.e., materials which will not volatilize when heated to 110°C for 15 minutes.
  • the cationic electrodepositable coating composition may be deposited upon an electrically conductive substrate by placing the composition in contact with an electrically conductive cathode and an electrically conductive anode, with the surface to be coated being the cathode.
  • the anionic electrodepositable coating composition may be deposited upon an electrically conductive substrate by placing the composition in contact with an electrically conductive cathode and an electrically conductive anode, with the surface to be coated being the anode.
  • An adherent film of the electrodepositable coating composition is deposited in a substantially continuous manner on the cathode or anode, respectively, when a sufficient voltage is impressed between the electrodes.
  • the applied voltage may be varied and can be, for example, as low as one volt to as high as several thousand volts, such as between 50 and 500 volts.
  • Current density is usually between 1.0 ampere and 15 amperes per square foot (10.8 to 161.5 amperes per square meter) and tends to decrease quickly during the electrodeposition process, indicating formation of a continuous self-insulating film.
  • the coated substrate is heated to a temperature and for a time sufficient to cure the electrodeposited coating on the substrate.
  • the coated substrate may be heated to a temperature ranging from 250°F to 450°F (121.1°C to 232.2°C), such as from 275°F to 400°F (135°C to 204.4°C), such as from 300°F to 360°F (149°C to 180°C).
  • the coated substrate may be heated to a temperature ranging from 180°F to 450°F (82.2°C to 232.2°C), such as from 275°F to 400°F (135°C to 204.4°C), such as from 300°F to 360°F (149°C to 180°C), such as 200°F to 210.2°F (93°C to 99°C).
  • the curing time may be dependent upon the curing temperature as well as other variables, for example, the film thickness of the electrodeposited coating, level and type of catalyst present in the composition and the like.
  • the curing time can range from 10 minutes to 60 minutes, such as 20 to 40 minutes.
  • the thickness of the resultant cured electrodeposited coating may range from 2 to 50 microns.
  • a powder coating composition may then be deposited onto at least a portion of the surface of the substrate.
  • powder coating composition refers to a coating composition which is completely free of water and/or solvent. Accordingly, the powder coating composition disclosed herein is not synonymous to waterborne and/or solvent-borne coating compositions known in the art.
  • the powder coating composition may comprise (a) a film forming polymer having a reactive functional group; and (b) a curing agent that is reactive with the functional group.
  • powder coating compositions that may be used in the present invention include the polyester-based ENVIROCRON line of powder coating compositions (commercially available from PPG Industries, Inc.) or epoxy-polyester hybrid powder coating compositions.
  • curable powder coating compositions generally comprising (a) at least one tertiary aminourea compound, at least one tertiary aminourethane compound, or mixtures thereof, and (b) at least one film-forming epoxy-containing resin and/or at least one siloxane-containing resin (such as those described in U.S. Patent No. 7,432,333, assigned to PPG Industries, Inc. and incorporated herein by reference); and those ccomprising a solid particulate mixture of a reactive group- containing polymer having a T g of at least 30°C (such as those described in U.S. Patent No. 6,797,387, assigned to PPG Industries, Inc. and incorporated herein by reference).
  • glass transition temperature is a theoretical value being the glass transition temperature as calculated by the method of Fox on the basis of monomer composition of the monomer charges according to T. G. Fox, Bull. Am. Phys. Soc. (Se. 11)1, 123 (1056) and J. Bandrup, E. H. Immergut, Polymer Handbook 3 rd edition, John Wiley, New York, 1989.
  • the coating is often heated to cure the deposited composition.
  • the heating or curing operation is often carried out at a temperature in the range of from 150°C to 200°C, such as from 170°C to 190°C, for a period of time ranging from 10 to 20 minutes.
  • the thickness of the resultant film is from 50 microns to 125 microns.
  • the coating composition may be a liquid coating composition.
  • liquid coating composition refers to a coating composition which contains a portion of water and/or organic solvent. Accordingly, the liquid coating composition disclosed herein is synonymous to waterborne and/or solvent-borne coating compositions known in the art.
  • the liquid coating composition may comprise, for example, (a) a film forming polymer having a reactive functional group; and (b) a curing agent that is reactive with the functional group.
  • the liquid coating may contain a film forming polymer that may react with oxygen in the air or coalesce into a film with the evaporation of water and/or solvents. These film forming mechanisms may require or be accelerated by the application of heat or some type of radiation such as Ultraviolet or Infrared.
  • liquid coating compositions examples include the SPECTRACRON® line of solvent-based coating compositions, the AQUACRON® line of water-based coating compositions, and the RAYCRON® line of UV cured coatings (all commercially available from PPG Industries, Inc.).
  • Suitable film forming polymers may comprise a (poly)ester, an alkyd, a (poly)urethane, an isocyanate, a (poly)urea, a (poly)epoxy, an anhydride, an acrylic, a (poly)ether, a (poly)sulfide, a (poly)amine, a (poly)amide, (poly)vinyl chloride, (poly)olefm, (poly)vinylidene fluoride, (poly)siloxane, or combinations thereof.
  • the substrate that has been contacted with the sealing composition may also be contacted with a primer composition and/or a topcoat composition.
  • the primer coat may be, for examples, chromate-based primers and advanced performance topcoats.
  • the primer coat can be a conventional chromate based primer coat, such as those available from PPG Industries, Inc. (product code 44GN072), or a chrome-free primer such as those available from PPG (DESOPRIME CA7502, DESOPRIME CA7521, Deft 02GN083, Deft 02GN084).
  • the primer coat can be a chromate-free primer coat, such as the coating compositions described in U.S. patent application Serial No.
  • the substrate of the present invention also may comprise a topcoat.
  • topcoat refers to a mixture of binder(s) which can be an organic or inorganic based polymer or a blend of polymers, and typically at least one pigment, which can optionally contain at least one solvent or mixture of solvents, and can optionally contain at least one curing agent.
  • a topcoat is typically the coating layer in a single or multi layer coating system whose outer surface is exposed to the atmosphere or environment, and its inner surface is in contact with another coating layer or polymeric substrate. Examples of suitable topcoats include those conforming to MIL-PRF-85285D, such as those available from PPG (Deft 03 W 127 A and Deft 03GY292).
  • the topcoat may be an advanced performance topcoat, such as those available from PPG (Defthane® ELT.TM. 99GY001 and 99W009).
  • PPG Dethane® ELT.TM. 99GY001 and 99W009
  • other topcoats and advanced performance topcoats can be used in the present invention as will be understood by those of skill in the art with reference to this disclosure.
  • the metal substrate also may comprise a self priming topcoat, or an enhanced self-priming topcoat.
  • self-priming topcoat also referred to as a “direct to substrate” or “direct to metal” coating, refers to a mixture of a binder(s), which can be an organic or inorganic based polymer or blend of polymers, and typically at least one pigment, which can optionally contain at least one solvent or mixture of solvents, and can optionally contain at least one curing agent.
  • enhanced self-priming topcoat also referred to as an "enhanced direct to substrate coating” refers to a mixture of functionalized fluorinated binders, such as a fluoroethylene-alkyl vinyl ether in whole or in part with other binder(s), which can be an organic or inorganic based polymer or blend of polymers, and typically at least one pigment, which can optionally contain at least one solvent or mixture of solvents, and can optionally contain at least one curing agent.
  • binder(s) can be an organic or inorganic based polymer or blend of polymers
  • typically at least one pigment which can optionally contain at least one solvent or mixture of solvents, and can optionally contain at least one curing agent.
  • self-priming topcoats include those that conform to TT-P-2756A.
  • self-priming topcoats examples include those available from PPG (03W169 and 03GY369), and examples of enhanced self-priming topcoats include Defthane® ELTTM/ESPT and product code number 97GY121, available from PPG.
  • other self-priming topcoats and enhanced self-priming topcoats can be used in the coating system according to the present invention as will be understood by those of skill in the art with reference to this disclosure.
  • the self-priming topcoat and/or enhanced self priming topcoat may be applied directly to the sealed substrate.
  • the self-priming topcoat and enhanced self-priming topcoat can optionally be applied to an organic or inorganic polymeric coating, such as a primer or paint film.
  • the self-priming topcoat layer and enhanced self priming topcoat is typically the coating layer in a single or multi-layer coating system where the outer surface of the coating is exposed to the atmosphere or environment, and the inner surface of the coating is typically in contact with the substrate or optional polymer coating or primer.
  • the topcoat, self-priming topcoat, and enhanced self-priming topcoat can be applied to the sealed substrate, in either a wet or “not fully cured” condition that dries or cures over time, that is, solvent evaporates and/or there is a chemical reaction.
  • the coatings can dry or cure either naturally or by accelerated means for example, an ultraviolet light cured system to form a film or “cured” paint.
  • the coatings can also be applied in a semi or fully cured state, such as an adhesive.
  • a colorant and, if desired, various additives such as surfactants, wetting agents or catalyst can be included in the coating composition (electrodepositable, powder, or liquid).
  • the term “colorant” means any substance that imparts color and/or other opacity and/or other visual effect to the composition.
  • Example colorants include pigments, dyes and tints, such as those used in the paint industry and/or listed in the Dry Color Manufacturers Association (DCMA), as well as special effect compositions.
  • the colorant can be present in the coating composition in any amount sufficient to impart the desired visual and/or color effect.
  • the colorant may comprise from 1 to 65 weight percent, such as from 3 to 40 weight percent or 5 to 35 weight percent, with weight percent based on the total weight of the composition.
  • Deoxidizer Compositions C and D were prepared per manufacturer’s instructions.
  • Composition E was prepared by first dissolving the chromium salt in approximately half of the water under mild mechanical stirring, without heat, using a ceramic stirring hotplate (VWR catalogue number 97042-642). Then, the zirconium salt was dissolved in the balance of the water in a separate beaker under mild mechanical stirring, without heat, using the ceramic stirring hotplate. The solution was then blended and left to sit for a minimum of 5 days before use.
  • Sealing Composition F was prepared by dissolving the lithium carbonate in the entirety of water under mild mechanical stirring, without heat, using a ceramic stirring hotplate (VWR catalogue number 97042-642). Next the molybdenum salt was added to the lithium carbonate solution and stirred, without heat, using a ceramic stirring hotplate (VWR catalogue number 97042-642).
  • Sealing Compositions G to H were prepared by dissolving the salt in water under mild mechanical stirring, without heat, using a ceramic stirring hotplate (VWR catalogue number 97042-642).
  • the panels were immersed in a deoxidizing solution of Example C for 5 minutes at ambient temperature followed by a tap water immersion rinse for 1 minute at ambient temperature with mild agitation followed by a second immersion in tap water rinse for 1 minutes at ambient temperature with mild agitation. The panels were then rinsed with a gentle deionized water spray for 5 seconds. The panels were then placed in the conversion bath solution of Example E for 6 minutes at ambient temperature with mild agitation followed by a deionized water immersion rinse for 2 minutes at ambient temperature with mild agitation followed by a second immersion in deionized water rinse for 2 minutes at ambient temperature with mild agitation. The panels were then rinsed with a gentle deionized water spray for 5 seconds.
  • a second panel was analyzed to determine the concentration of the elements shown at various depths using XPS depth profiling. Data are shown in Fig. 1.
  • Peaks were charge referenced to CHx band in the carbon Is spectra at 284.8 eV. Measurements were made at a takeoff angle of 45° with respect to the sample surface plane. This resulted in a typical sampling depth of 3-6 nm (95% of the signal originated from this depth or shallower). Quantification was done using instrumental relative sensitivity factors (RSFs) that account for the x-ray cross section and inelastic mean free path of the electrons. Depth profiling was done using a 4 kV Ar+ beam rastered over a 3 mm x 3 mm area. The samples were rotated during profiling to minimize any roughening. The sputtering rate for Si02 under these conditions was 14.2 nm/min.
  • the panel was immersed in a deoxidizing solution of Example D for 7 minutes at 81°F with mild agitation followed by a tap water immersion rinse for 5 minutes at 81°F with mild agitation followed by a second tap water immersion rinse for 2 minutes at 81°F with mild agitation.
  • the panel was then rinsed with a gentle deionized water spray for 5 seconds.
  • the panel was then placed in the conversion bath solution of Example E for 6 minutes at ambient temperature with mild agitation followed by a deionized water immersion rinse for 5 minutes at 77°F with mild agitation followed by a second immersion rinse in deionized water for 5 minutes at ambient temperature.
  • the panel was then rinsed with a gentle deionized water spray for 5 seconds.
  • the panel was left to dry for a minimum of 18 hours at ambient conditions before being placed in a neutral salt spray cabinet operated according to ASTM B117 for 14 day corrosion testing. Corrosion performance was evaluated by counting the number of pits visible to the naked eye on the panel. Data are reported in Table 12.
  • the panel was immersed in a deoxidizing solution of Example C for 5 minutes at ambient temperature followed by a tap water immersion rinse for 1 minute at ambient temperature with mild agitation followed by a second immersion in tap water rinse for 1 minutes at ambient temperature with mild agitation. The panel was then rinsed with a gentle deionized water spray for 5 seconds. The panel was then placed in the conversion bath solution of Example E for 6 minutes at ambient temperature with mild agitation followed by a deionized water immersion rinse for 2 minutes at ambient temperature with mild agitation followed by a second immersion in deionized water rinse for 2 minutes at ambient temperature with mild agitation. The panel was then rinsed with a gentle deionized water spray for 5 seconds. The panel was then immersed in the seal solution of Example F for 2 minutes at ambient temperature with intermittent agitation.
  • the panel was left to dry for a minimum of 18 hours at ambient conditions before being placed in a neutral salt spray cabinet operated according to ASTM B117 for 14 day corrosion testing. Corrosion performance was evaluated by counting the number of pits visible to the naked eye on the panel. Data are reported in Table 12.
  • the panels were immersed in a deoxidizing solution of Example C for 5 minutes at ambient temperature followed by a tap water immersion rinse for 1 minute at ambient temperature with mild agitation followed by a second immersion in tap water rinse for 1 minutes at ambient temperature with mild agitation. The panels were then rinsed with a gentle deionized water spray for 5 seconds. The panels were then placed in the conversion bath solution of Example E for 6 minutes at ambient temperature with mild agitation followed by a deionized water immersion rinse for 2 minutes at ambient temperature with mild agitation followed by a second immersion in deionized water rinse for 2 minutes at ambient temperature with mild agitation. The panels were then rinsed with a gentle deionized water spray for 5 seconds. After, the panels were immersed in the seal solution of Example G for 1 minute at ambient temperature with intermittent agitation. The panels were then rinsed with a gentle deionized water spray for 5 seconds.
  • the second panel was analyzed to determine the concentration of the elements shown at various depths using XPS depth profiling as described in Example 1. Data are shown in Fig. 1.
  • the panel was immersed in a deoxidizing solution of Example D for 7 minutes at 81°F with mild agitation followed by a tap water immersion rinse for 5 minutes at 81°F with mild agitation followed by a second tap water immersion rinse for 2 minutes at 81°F with mild agitation.
  • the panel was then rinsed with a gentle deionized water spray for 5 seconds.
  • the panel was then placed in the conversion bath solution of Example E for 6 minutes at ambient temperature with mild agitation followed by a deionized water immersion rinse for 5 minutes at 77°F with mild agitation followed by a second immersion rinse in deionized water for 5 minutes at ambient temperature.
  • the panel was then rinsed with a gentle deionized water spray for 5 seconds.
  • the panel was immersed in the seal solution of Example G for 1 minute at ambient temperature with intermittent agitation.
  • the panel was then rinsed with a gentle deionized water spray for 5 seconds.
  • the panel was left to dry for a minimum of 18 hours at ambient conditions before being placed in a neutral salt spray cabinet operated according to ASTM B117 for 14 day corrosion testing. Corrosion performance was evaluated by counting the number of pits visible to the naked eye on the panel. Data are reported in Table 12.
  • the panel was immersed in a deoxidizing solution of Example C for 5 minutes at ambient temperature followed by a tap water immersion rinse for 5 minutes at 81°F with mild agitation followed by a second immersion in tap water rinse for 2 minutes at 104°F with mild agitation. The panel was then rinsed with a gentle deionized water spray for 5 seconds. The panel was then placed in the conversion bath solution of Example E for 6 minutes at ambient temperature with mild agitation followed by a deionized water immersion rinse for 5 minutes at 77°F with mild agitation followed by a second immersion rinse in deionized water for 5 minutes at ambient temperature. The panel was then rinsed with a gentle deionized water spray for 5 seconds.
  • Example H Example H
  • Example H Example H
  • the panel was then rinsed with a gentle deionized water spray for 5 seconds.
  • the panel was left to dry for a minimum of 18 hours at ambient conditions before being placed in a neutral salt spray cabinet operated according to ASTM B117 for 14 day corrosion testing. Corrosion performance was evaluated by counting the number of pits visible to the naked eye on the panel. Data are reported in Table 12.
  • the panel was immersed in a deoxidizing solution of Example C for 5 minutes at ambient temperature followed by a tap water immersion rinse for 5 minutes at 81°F with mild agitation followed by a second immersion in tap water rinse for 2 minutes at 104°F with mild agitation. The panel was then rinsed with a gentle deionized water spray for 5 seconds. The panel was then placed in the conversion bath solution of Example E for 6 minutes at ambient temperature with mild agitation followed by a deionized water immersion rinse for 5 minutes at 77°F with mild agitation followed by a second immersion rinse in deionized water for 5 minutes at ambient temperature. The panel was then rinsed with a gentle deionized water spray for 5 seconds. After, the panel was immersed in the seal solution of Example I for 1 minute at ambient temperature with intermittent agitation. The panel was then rinsed with a gentle deionized water spray for 5 seconds.
  • the panel was left to dry for a minimum of 18 hours at ambient conditions before being placed in a neutral salt spray cabinet operated according to ASTM B117 for 14 day corrosion testing. Corrosion performance was evaluated by counting the number of pits visible to the naked eye on the panel. Data are reported in Table 12.
  • Results are reported in Table 12 as the total number of pits across the face of the sample. Pits were counted as any corrosion event where white corrosion product was present and were counted with the unaided eye. Table 12 - Corrosion Performance (Pits) on Panels Treated According to Examples 1-7
  • Examples 4-7 following 14 days of exposure to neutral salt spray results compared to those counted on the panel treated according to comparative Examples 1 and 2 shows the benefit of treating the substrate with a seal containing an ammonium-containing compound following treatment of the substrate with a conversion composition containing trivalent chromium.
  • Evidence of the improvement is seen by the reduction in the number of pits on the surface of the treated substrate panels (Examples 4 and 6 had 2 pits, Example 5 had 1 pit, and Example 7 had 3 pits) after exposure to neutral salt spray for 14 days (ASTM B117), while comparative Example 1 had 25 pits and comparative Example 2 had 10 pits.
  • Example 4 and Example 6 following 14 days of exposure to neutral salt spray compared to those counted on the panel treated according to comparative Example 3 shows the benefit of treating the substrate with a seal containing an ammonium-containing compound over a seal containing lithium and molybdenum following treatment of the substrate with a conversion composition containing trivalent chromium.
  • Evidence of the improvement is seen by the reduction in the number of pits on the surface of the treated substrate (Example 4 and Example 6 each had 2 pits, while comparative Example 3 had 12 pits).
  • the fluoride level in a panel not treated with the ammonium-containing seal composition was about 7 atomic percent at the air-surface interface and increased to about 9 atomic percent at about 50 nm below the air-surface interface.
  • the fluoride level in a panel treated with the ammonium-containing seal composition following application of the TCP conversion composition had reduced fluoride content at the air-surface interface was reduced to about 2.5 atomic percent and had reduced fluoride content at about 50 nm below the air-surface interface to about 4 atomic percent.
  • the fluoride content persists deeper below the air-substrate interface (i.e., to about 225 nm below the air-substrate interface) in a panel not treated with the ammonium-containing seal composition compared to a panel that was treated with the ammonium-containing seal composition (i.e., the fluoride content only persists to about 175 nm below the air-substrate interface).
  • the content of chromium and zirconium remain substantially intact regardless of whether the substrate was treated with the ammonium- containing seal composition or not.
  • the reduction in fluoride content at and below the air- surface interface correlates with a reduction in pitting on the substrate surface (i.e., an improvement in corrosion performance).

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  • Chemical Kinetics & Catalysis (AREA)
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  • Mechanical Engineering (AREA)
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Abstract

L'invention concerne un système de traitement d'un substrat métallique comprenant une composition de conversion comprenant du chrome trivalent en une quantité de 0,001 g/L à 20 g/L et une composition d'étanchéité comprenant un composé contenant de l'ammonium. L'invention concerne en outre un procédé de traitement d'un substrat métallique, comprenant la mise en contact d'au moins une partie d'une surface du substrat avec la composition de conversion et ensuite la mise en contact d'au moins une partie de la surface du substrat avec la composition d'étanchéité. L'invention concerne également un substrat pouvant être obtenu par traitement avec le système et/ou pouvant être obtenu par le procédé de traitement.
EP20845479.3A 2019-12-26 2020-12-23 Systèmes et procédés de traitement d'un substrat métallique Withdrawn EP4081672A1 (fr)

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CA2028191C (fr) * 1989-10-23 2001-04-24 Ahmed Sharaby Compositions non toxiques inhibitrices de corrosion et methodes connexes
US5711996A (en) * 1995-09-28 1998-01-27 Man-Gill Chemical Company Aqueous coating compositions and coated metal surfaces
US6797387B2 (en) 2000-09-21 2004-09-28 Ppg Industries Ohio Inc. Modified aminoplast crosslinkers and powder coating compositions containing such crosslinkers
US7091286B2 (en) 2002-05-31 2006-08-15 Ppg Industries Ohio, Inc. Low-cure powder coatings and methods for using the same
US8323470B2 (en) 2007-08-15 2012-12-04 Ppg Industries Ohio, Inc. Electrodeposition coatings for use over aluminum substrates
IT1393946B1 (it) * 2009-04-21 2012-05-17 Np Coil Dexter Ind Srl Processo di trattamento in continuo di patinatura/satinatura chimica di leghe zinco-titanio
US10745568B2 (en) * 2015-06-03 2020-08-18 Atotech Deutschland Gmbh Surface treatment composition
EP3497264A1 (fr) * 2016-08-12 2019-06-19 PRC-Desoto International, Inc. Systèmes et procédés de traitement d'un substrat métallique
CA3032158A1 (fr) * 2016-08-12 2018-02-15 Prc-Desoto International, Inc. Systemes et procedes de traitement d'un substrat metallique par pretraitement de film mince et composition d'etancheite
WO2019152556A1 (fr) * 2018-01-30 2019-08-08 Prc-Desoto International, Inc. Systèmes et procédés de traitement d'un substrat métallique

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AU2020414711A1 (en) 2022-07-21
CA3161211A1 (fr) 2021-07-01

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