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
  • C23C22/68—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous solutions with pH between 6 and 8
• • 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

Definitions

• This invention relates to the treatment of metals, and more particularly to the treatment of the zinc- surface of galvanized iron, galvanized steel, and the like to increase the resistance to corrosion of these metals.
• compositions useful for this purpose are (i) acidic compositions and (ii) alkaline compositions.
• Acidic compositions which form phosphate or chro- mate coatings on the zinc, are described in U.S. patent No. 3,297,494.
• Alkaline coatings are widely used and examples of such coatings are disclosed in U.S. patents Nos. 3,444,007; 3,515,600 and 4,278,477.
• an aqueous coating solution for metals such as galvanized iron and steel, aluminum, and ferrous metals such as steel, which contains:
• a fluorometallic acid such as HBF4, H2SiF ⁇ , H2 iF ⁇ , and ⁇ ZrFg or an ammo ⁇ nium or alkali metal salt thereof;
• hydrofluoric acid or a salt thereof or
• a salt or a metal such as cobalt, copper, iron, manga ⁇ nese, nickel, strontium, and zinc, or a mix ⁇ ture of two or more of the foregoing
• a sequestrant in an amount of from a 1:1 molar
• ⁇ TiFg is the preferred fluorometallic acid and is commonly used as a 60% aqeous solution in the preparation of the compositions of this invention, and is preferably used in a quantity equal to about 1.4 g/liter of fluoride.
• the salt of hydrofluoric acid can be an ammonium or alkali metal salt, or a fluoride of a metal of component (b) pro- vided the ranges for fluoride or metal are not exceeded.
• Component (a)(iii) can be a mixture of (i) and (ii) in any proportion.
• the preferred salts of cobalt, copper, iron, manganese, nickel, strontium and zinc in addition to the fluoride salts are their carbonates and bicarbonates. This serves to avoid the introduction of anions other than fluoride into the coating composition.
• any salt of these metals may be used provided the anion which is introduced is not detrimental to the stability of the formulations and to the coating.
• acceptable anions include sulfate and chloride.
• sequestrant (c) is an optional ingre ⁇ + While the sequestrant (c) is an optional ingre ⁇ +, it is beneficial to have this component present since the presence of a sequestrant extends the useful pH range of the aqueous coating solution from 2 to 5, preferably about 4, without the sequestrant, to from 2 to 7 with the sequestrant.
• Sequestrants that can be employed herein include the following compounds, seqestrant-active derivatives thereof, or alkali metal or ammonium salts thereof: nitrilotriacetic acid (NTA), ethylenediamine tetraacetic acid (EDTA), gluconic acid, and citric acid.
• NTA nitrilotriacetic acid
• EDTA ethylenediamine tetraacetic acid
• gluconic acid gluconic acid
• citric acid citric acid
• a preferred polymer is ACRYSOL A-l, a 25% aqueous solution of a water-soluble polyacrylic acid having a molecular weight of up to about 500,000 (available from Rohm and Haas Co. ) .
• ACRYSOL A-l a 25% aqueous solution of a water-soluble polyacrylic acid having a molecular weight of up to about 500,000 (available from Rohm and Haas Co. ) .
• prior prepared concentrated aqueous solutions of the above ingredients which are added to water in an amount to provide a coating solution of the desired composition and concentration.
• the concentrated aqueous solutions contain component (a) in a con ⁇ centration of at least about 1 g/1, preferably from about 1 to about 15 g/1 based on fluoride content, with the quantities of the other components increased pro ⁇ portionally so that dilution with water will give the aqueous coating solution compositions disclosed above.
• the concentrate contains the desired ingre ⁇ washers in sufficient amounts so that a ten-fold dilu ⁇ tion by volume of the concentrate will provide an aqueous coating solution having the desired composition and concentration.
• concentrates containing the above ingredients up to their solubility limits in water can also be used herein.
• the concentrates can be formulated as described above, or quantities of bases such as NaOH, NH4OH, (NH4)2C03, or Na2C ⁇ 3 or an acid such as H2SO4 can be added so that upon dilution the correct pH is obtained for the coating solutions.
• the coating solution can be applied by brushing, spraying, dipping, roll-coating and the like, with spraying or dipping being preferred.
• the metal is preferably first cleaned, using an alkaline cleaner such as
• RIDOLINE 1089 which is composed of sodium carbonate, sodium hydroxide, sodium polyphosphate, and surfactants and is available from Amchem Products, Inc. of Ambler, Pa.
• the cleaned metal is then rinsed with water and sprayed with or dipped into the coating solution of the invention which is kept at 60°F to 160°F, preferably from 110°F to 140°F, for 1 to 300, preferably from 5 to 30 seconds.
• the coated metals are then rinsed with water.
• a final rinse such as a final chrome rinse with DEOXYLYTE 41, an aqueous solution containing chromic acid and formaldehyde (available from Amchem Products, Inc.), is then used.
• a sic ⁇ cative coating can thereafter be applied to the metal.
• the ingredients therein decrease in concentration and it becomes necessary to replace them. Although it is always possible to prepare a fresh solution, this is wasteful of materials present in the solution which can still be used , and is also time consuming. In practice, it is desirable to use a replenishing concentrate, and the concentrates disclosed above for use in forming the aqueous coating solutions of the invention can also be used as replenishing concentrates.
• Examples 1 to 10 illustrate concentrate composi ⁇ tions according to this invention.
• the desired amounts of the ingredients were dissolved in water and additional water added to bring the concentrate to the desired volume.
• Examples 11 through 12 illustrate coating solu ⁇ tions prepared from various concentrates and the pro ⁇ Defines of treating galvanized metals with these coating solutions.
• a coating solution was prepared by diluting 10 liters of the concentrate of Example 1 to 100 liters with deionized water. The pH of the solutions was adjusted to about 4.0 by the addition of ammonium hydroxide.
• Armo G-60 and G-90 hot dipped galvanized steel panels were first cleaned by spraying for 15 sec. with an aqueous solution (1 oz/gal) of RIDOLINE 1089 at about 130°F. The panels were then rinsed with water and then immersed in the coating solution, prepared as described above, for 15 seconds at a temperature of about 130°F. The coated panels were then rinsed in water and dried. The protective coating was dark in color. The coated panels were very resistant to corrosion and the protec ⁇ tive coatings thereon possessed good adherence to sub ⁇ sequently applied siccative coatings such as polyester, polyester melamines, siliconized polyesters, fluorocar- bons, and the like using epoxy or acrylic primers.
• siccative coatings such as polyester, polyester melamines, siliconized polyesters, fluorocar- bons, and the like using epoxy or acrylic primers.
• Example 11 The procedure of Example 11 was repeated using the concentrate of Example 5.
• the coating was somewhat lighter in color than the coating of Example 11. This is apparently due to the presence of the acrylic polymer.
• the coating provided good protection against corrosion and possessed good adhesion to subsequently applied siccative coatings.
• similar dark coatings providing good resistance to corrosion and having good adhesion to applied siccative coatings, were obtained.
• the replenisher concentrate is added until the pH of the bath is brought into the operating range given above.
• Replenisher concentrates for coating solutions containing other ingredients may be prepared by having in the replenisher concentrate the same fluorometallic acid and the same metallic ion which are present in the coating solution.
• a coating solution was prepared by adding the following ingredients to deionized water:
• Armo G-60 and G-90 hot dipped galvanized steel panels were first cleaned by spraying for 15 sec. with an aqueous solution (1 oz/gal) of RIDOLINE 1089 at about 130°F. The panels were then rinsed with water and then immersed in the coating solution, prepared as described above, for 7 seconds at a temperatre of about 130°F. The coated panels were then rinsed in water and dried. The protective coating was dark in color. The coated panels were very resistant to corrosion and the protective coatings thereon possessed good aherence to subsequently applied siccative coatings such as poly ⁇ esters, polyester melamines, siliconized polyesters, fluorocarbons, and the like using epoxy or acrylic pri- mers.
• siccative coatings such as poly ⁇ esters, polyester melamines, siliconized polyesters, fluorocarbons, and the like using epoxy or acrylic pri- mers.
• Example 14 The process of Example 14 was carried out except that in A. 4.2 g/1 of disodium EDTA was used instead of 0.6 g/1 of citric acid, and B. the treatment time was 15 seconds. The same results were obtained.
• Example 14 The process of Example 14 was carried out except that in A. 4.9 g/1 of gluconic acid was present in place of 0.6 g/1 of citric acid. The same results were obtained. "
• a coating solution was prepared by adding the following ingredients to deionized water:
• Armo G-60 and G-90 hot dipped galvanized steel panels were first cleaned by spraying for 15 sec. with an aqueous solution (1 oz/gal) of RIDOLINE 1089 at about 130°F. The panels were then rinsed with water and then immersed in the coating solution, prepared as described above, for 15 seconds at a temperature of about 130°F. The coated panels were then rinsed in water and dried. The protective coating was dark in color. The coated panels were very resistant to corro ⁇ sion and the protective coatings thereon possessed good adherence to subsequently applied siccative coatings such as polyesters, polyester melamines, siliconized polyesters, fluorocarbons, and the like using epoxy or acrylic primers.
• siccative coatings such as polyesters, polyester melamines, siliconized polyesters, fluorocarbons, and the like using epoxy or acrylic primers.

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• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Treatment Of Metals (AREA)
• Superconductors And Manufacturing Methods Therefor (AREA)
• Glass Compositions (AREA)

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• 1985
  • 1985-05-03 EP EP19850902388 patent/EP0181377A4/fr not_active Withdrawn
  • 1985-05-03 AU AU42958/85A patent/AU4295885A/en not_active Abandoned
  • 1985-05-03 WO PCT/US1985/000797 patent/WO1985005131A1/fr not_active Application Discontinuation
• 1986
  • 1986-01-03 DK DK2786A patent/DK2786A/da not_active Application Discontinuation
  • 1986-01-03 FI FI860032A patent/FI860032A0/fi not_active Application Discontinuation

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