US3014821A - Process of producing dyed chromate surfaces on zinc and cadmium - Google Patents

Process of producing dyed chromate surfaces on zinc and cadmium Download PDF

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Publication number
US3014821A
US3014821A US823011A US82301159A US3014821A US 3014821 A US3014821 A US 3014821A US 823011 A US823011 A US 823011A US 82301159 A US82301159 A US 82301159A US 3014821 A US3014821 A US 3014821A
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metal
cadmium
zinc
solution
immersing
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US823011A
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Jr Edgar J Seyb
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Metal & Tuermit Corp
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Metal & Tuermit Corp
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Priority to US823011A priority Critical patent/US3014821A/en
Priority to GB17908/60A priority patent/GB889184A/en
Priority to FR829928A priority patent/FR1261490A/en
Priority to DE19601446513 priority patent/DE1446513A1/en
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/82—After-treatment
    • C23C22/84—Dyeing

Definitions

  • the present invention relates to a process for providing a dyed corrosion resistant surface on zinc and cadmium.
  • Zinc and cadmium are commonly rendered corrosion resistant by applying chromate conversion coatings to their surfaces. These coatings are formed by immersing the piece in a chromic acid solution. The resultant conversion coatings are usually clear, yellow tinted varying to a deep olive drab, or black. It is often desirable to obtain more decorative colors. The known techniques for coloring these coatings have been extremely limited. I have now discovered an economical and widely applicable method of dyeing such coatings to desired colors.
  • My invention contemplatesimmersing zinc or cadmium in a chromic acid bath, of the type used to obtain con version coatings, until an efiective and reasonably thick chromate coating is built up.
  • the piece is then removed, rinsed, and while wet, immersed in a leaching solution for a few seconds to-as many as two or three minutes. Following the leaching treatment, the piece is removed, rinsed, and inserted in a dye solution until the' desired color is obtained.
  • the initial conversion coating is applied by immersing the metal in a chromic acid solution containing 3- 150 g./l; (grams per liter) of chromic acid (CrO sulfate ions to give a CrO /SO ratio from 3:1 to about 15 :1; the nitrate ions to give a CrO /NO ratio from about 1:1 to about 12:1.
  • CrO sulfate ions to give a CrO /SO ratio from 3:1 to about 15 :1
  • the nitrate ions to give a CrO /NO ratio from about 1:1 to about 12:1.
  • These components may be added as salts of sodium or potassium as well as in the form of acids. They should be added in acid form sufficient to give a pH of less than about 2.0 and preferably less than 1.0. Additional materials such as acetic acid or boric acid are often used in baths of this type. Treatm nt in this chromating solution is usually from about to 30 seconds at room temperature.
  • the leaching treatment which immediately follows the chromating treatment is carried out in an aqueous alkaline solution prepared from anions such as hydroxide, carbonate, phosphate, silicate, etc.
  • aqueous alkaline solution prepared from anions such as hydroxide, carbonate, phosphate, silicate, etc.
  • These solutions preferably contain from about 2 to about 40 g./l. of the 3,l4,821 Patented Dec. Zfi, 1961 alkaline chemical.
  • the temperatures vary from room temperature to almost the boiling point of the solution, preferably between about 20 C. to 60 C.
  • the time of leaching varies from about a few seconds to about two or three minutes. A preferred period is from ten to thirty seconds 'at room temperature.
  • the choice of the particular leaching condition utilized is dependent upon the conversion coating first placed on the piece, and the subsequent dye used and color (shade) desired. Longer immersion in the leach solution and higher temperatures generally result in a greater amount of leaching which 'on subsequent dyeing results in
  • the piece After removal from the leach solution, the piece is rinsed and then immersed into a dye solution.
  • a large number of dyes may be used, dependent upon the color desired.
  • the particular dye solution utilized and the conditions, i.e., temperature, pH, etc., existing in the bath at the time of the dye application vary with the particular dye utilized, the type and condition 'of the conversion coating being dyed, and the color desired.
  • the most elfective dye concentration depends on the particular dye utilized. From about one-quarter to five grams per liter are satisfactory for most dyes, although other concentrations are also operative. Increasing the concentration usually increases the rate of absorption so that a specific depth of color is obtained in a shorter time. the depth of color desired.
  • the temperatures are not critical. They may range from room temperature (as low as 15 C.) to about 70 C. Higher temperatures increase the :rate of dye absorption so that deeper-colors are usuallyobta'inecl in a shorter time.
  • the pH of the dye solution will vary according to the particular dye utilized. A buffered solution may be useful in some cases where either alkaline or acid solutions are dragged into the dye solution.
  • Suitable leaching solutions have been prepared from potassium hydroxide, sodium phosphate, sodium silicate, sodium carbonate, potassium carbonate, sodium hydroxide; of these sodium hydroxide and sodium carbonate are preferred. It is also possible to leach the conversion coating in a water solution at temperatures in excess of about 70 C. Although this procedure may be used to produce light colors, the use of alkaline salts is preferred since more absorption of dye occurs to yield deeper colors.
  • the surface coated is zinc or cadmium. This includes clad metal, plated surfaces, and galvanized surfaces.
  • a process for producing dyed chromate conversion coatings comprising immersing an object surfaced with a metal selected from the class consisting of zinc and cadmium in a chromating solution containing between 3 and 150 g./l. of chromic acid to form a chromate conversion coating, withdrawing and rinsing said metal, then immersing said metal in a leach solution selected from the class consisting of water at a temperature in excess of 70 C., and aqueous alkaline solutions, withdrawing and rinsing said metal, and then immersing said metal in a dye solution until the desired color is obtained.
  • a process for producing dyed chromate conversion coatings comprising immersing a metal selected from the class consisting of zinc and cadmium between 10 and 30 seconds in a chromating solution containing between 3 and 150 g./l. of chromic acid to form a chromate conversion coating, Withdrawing and rinsing said metal, then immersing said metal between 10 and 30 seconds in an aqueous alkaline leach solution at a temperature between 20 C. and C., withdrawing and rinsing said metal, and then immersing said metal between 30 and 90 seconds in a dye solution at a temperature between 20 C. and 50 C. until the desired color is obtained.

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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)

Description

United States PatentG 3,014,821 PROCESS OF PRODUCING DYED CHRGMATE SURFACES N ZBIC AND CADMIUM Edgar J. Seyh, In, Oak Park, Mieln, assignor to Metal & Therniit Corporation, Woodbridge Township, NE, a corporation of New Jersey No Drawing. Filed June 26, 1959, Ser. No.823,9'11 8 Claims. (Cl. i486.1)
The present invention relates to a process for providing a dyed corrosion resistant surface on zinc and cadmium.
Zinc and cadmium are commonly rendered corrosion resistant by applying chromate conversion coatings to their surfaces. These coatings are formed by immersing the piece in a chromic acid solution. The resultant conversion coatings are usually clear, yellow tinted varying to a deep olive drab, or black. It is often desirable to obtain more decorative colors. The known techniques for coloring these coatings have been extremely limited. I have now discovered an economical and widely applicable method of dyeing such coatings to desired colors.
It is an object of this invention to provide a process for dyeing conversion coatings on zinc and cadmium.
It is still another object of this invention to provide a process for producing a colored surface on zinc and cadmium.
My invention contemplatesimmersing zinc or cadmium in a chromic acid bath, of the type used to obtain con version coatings, until an efiective and reasonably thick chromate coating is built up. The piece is then removed, rinsed, and while wet, immersed in a leaching solution for a few seconds to-as many as two or three minutes. Following the leaching treatment, the piece is removed, rinsed, and inserted in a dye solution until the' desired color is obtained.
The initial conversion coating is applied by immersing the metal in a chromic acid solution containing 3- 150 g./l; (grams per liter) of chromic acid (CrO sulfate ions to give a CrO /SO ratio from 3:1 to about 15 :1; the nitrate ions to give a CrO /NO ratio from about 1:1 to about 12:1. These components may be added as salts of sodium or potassium as well as in the form of acids. They should be added in acid form sufficient to give a pH of less than about 2.0 and preferably less than 1.0. Additional materials such as acetic acid or boric acid are often used in baths of this type. Treatm nt in this chromating solution is usually from about to 30 seconds at room temperature. The type (color) of the conversion coating will afiect the depth of color obtained. An iridescent yellow film, which is usually thicker than a clearcoating, gives a dyed article with a deeper color than would be obtained from an initially clear coating.
The leaching treatment which immediately follows the chromating treatment is carried out in an aqueous alkaline solution prepared from anions such as hydroxide, carbonate, phosphate, silicate, etc. These solutions preferably contain from about 2 to about 40 g./l. of the 3,l4,821 Patented Dec. Zfi, 1961 alkaline chemical. The temperatures vary from room temperature to almost the boiling point of the solution, preferably between about 20 C. to 60 C. The time of leaching varies from about a few seconds to about two or three minutes. A preferred period is from ten to thirty seconds 'at room temperature. The choice of the particular leaching condition utilized is dependent upon the conversion coating first placed on the piece, and the subsequent dye used and color (shade) desired. Longer immersion in the leach solution and higher temperatures generally result in a greater amount of leaching which 'on subsequent dyeing results in a deeper "color for given conditions.
After removal from the leach solution, the piece is rinsed and then immersed into a dye solution. A large number of dyes may be used, dependent upon the color desired. The particular dye solution utilized and the conditions, i.e., temperature, pH, etc., existing in the bath at the time of the dye application vary with the particular dye utilized, the type and condition 'of the conversion coating being dyed, and the color desired. The most elfective dye concentration depends on the particular dye utilized. From about one-quarter to five grams per liter are satisfactory for most dyes, although other concentrations are also operative. Increasing the concentration usually increases the rate of absorption so that a specific depth of color is obtained in a shorter time. the depth of color desired. Times from five seconds to five minutes have been used; preferably about 30 to '90 seconds. The temperatures are not critical. They may range from room temperature (as low as 15 C.) to about 70 C. Higher temperatures increase the :rate of dye absorption so that deeper-colors are usuallyobta'inecl in a shorter time. The pH of the dye solution will vary according to the particular dye utilized. A buffered solution may be useful in some cases where either alkaline or acid solutions are dragged into the dye solution.
Suitable leaching solutions have been prepared from potassium hydroxide, sodium phosphate, sodium silicate, sodium carbonate, potassium carbonate, sodium hydroxide; of these sodium hydroxide and sodium carbonate are preferred. It is also possible to leach the conversion coating in a water solution at temperatures in excess of about 70 C. Although this procedure may be used to produce light colors, the use of alkaline salts is preferred since more absorption of dye occurs to yield deeper colors.
For purposes of giving those skilled in the art a better understanding of the invention, the following illustrative examples are given: Samples of zinc and cadmium surfaced metal pieces were chromated in a solution containing g./l. of chromic acid, 8 g./l. of sulfuric acid, 3.5 g./l. of nitric acid, and 13 g./l. of acetic acid. Treatment in this solution was from 10 to 30 seconds, usually at room temperature. The pieces were then water-rinsed,
Increasing the time of immersion usually increases leached, water-rinsed and dyed. The conditions for leaching and dyeing are given in the following table:
4 solution contains between 65 g./l. and 150 g./l. of chromic acid.
Table I Leaching Coloring Example Color N0. Obtained Leech Chemical 00110., Temp, Time, Dye Trade Source Chemical pH 00110., Temp., Time,
g./l. C. Secs. Name Description gJl. C. Secs.
1 NaOH 7 32 2O Alizarin Hartman-Leddon Acid anthrn- 5.7 1.0 49 45 Pink.
Red S. Co. guinone ye. 2 KOH 15 21 10 Clayton -.do Also called 5.7 0.5 27 60 Green- Yellow. Thiazole ish Yellow. A Yelgiazoumino low. ye. 3 NazPOr-IZHzO-.. 25 ll) Alizarin do An azosali- 7.6 0.5 21 60 Golden Yellow cylic dye. Yel- R. low. 4 NazSiOa 25 38 30 Poinier d0 do 7.7 0.25 21 30 Dark Blue. Blue. 5 NB-sCOs 60 Ponta- El. du Pont de A dlazo dye... 9. 3 0. 26 21 30 Do.
mine Nernours. 113315101: 0 Hot Water 71 30 Pontado Anacld coal 7.0 0.5 21 30 Blue. chrome tar dye.
1.lglael:
The surface coated is zinc or cadmium. This includes clad metal, plated surfaces, and galvanized surfaces.
As many embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention includes all such modifications and variations as come within the scope of the appended claims.
I claim:
1. A process for producing dyed chromate conversion coatings comprising immersing an object surfaced with a metal selected from the class consisting of zinc and cadmium in a chromating solution containing between 3 and 150 g./l. of chromic acid to form a chromate conversion coating, withdrawing and rinsing said metal, then immersing said metal in a leach solution selected from the class consisting of water at a temperature in excess of 70 C., and aqueous alkaline solutions, withdrawing and rinsing said metal, and then immersing said metal in a dye solution until the desired color is obtained.
2. The process of claim 1 in which the surface metal is zinc.
3. The process of claim 1 in which the surface metal is cadmium.
4. The process of claim 1 in which the chromating 5. A process for producing dyed chromate conversion coatings comprising immersing a metal selected from the class consisting of zinc and cadmium between 10 and 30 seconds in a chromating solution containing between 3 and 150 g./l. of chromic acid to form a chromate conversion coating, Withdrawing and rinsing said metal, then immersing said metal between 10 and 30 seconds in an aqueous alkaline leach solution at a temperature between 20 C. and C., withdrawing and rinsing said metal, and then immersing said metal between 30 and 90 seconds in a dye solution at a temperature between 20 C. and 50 C. until the desired color is obtained.
6. The process of claim 5 in which the metal is zinc.
7. The process of claim 5 in which the metal is cadmium.
8. The process of claim 5 in which the chromating solution contains about g./1. of chromic acid.
References Cited in the file of this patent UNITED STATES PATENTS 2,393,640 King Ian. 29, 1946 2,417,310 McLean et a1. July 26, 1949 FOREIGN PATENTS 636,954 Great Britain May 10, 1950

Claims (1)

1. A PROCESS FOR PRODUCING DYED CHROMATE CONVERSION COATINGS COMPRISING IMMERSING AN OBJECT SURFACED WITH A METAL SELECTED FROM THE CLASS CONSISTING OF ZINC AND CADMIUM IN A CHROMATING SOLUTION CONTAINING BETWEEN 3 AND 150 G./L. OF CHROMIC ACID TO FORM A CHROMATE CONVERSION COATING, WITHDRAWING AND RINSING SAID METAL, THEN IMMERSING SAID METAL IN A LEACH SOLUTION SELECTED FROM THE CLASS CONSISTING OF WATER AT A TEMPERATURE IN EXCESS OF 70*C., AND AQUEOUS ALKALINE SOLUTIONS, WITHDRAWING AND RINSING SAID METAL, AND THEN IMMERSING SAID METAL IN A DYE SOLUTION UNTIL THE DESIRED COLOR IS OBTAINED.
US823011A 1959-06-26 1959-06-26 Process of producing dyed chromate surfaces on zinc and cadmium Expired - Lifetime US3014821A (en)

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Application Number Priority Date Filing Date Title
US823011A US3014821A (en) 1959-06-26 1959-06-26 Process of producing dyed chromate surfaces on zinc and cadmium
GB17908/60A GB889184A (en) 1959-06-26 1960-05-20 Improvements in or relating to the production of a dyed chromate conversion coating on a zinc or cadmium article
FR829928A FR1261490A (en) 1959-06-26 1960-06-14 Process for the formation on zinc and cadmium of colored chromate coatings
DE19601446513 DE1446513A1 (en) 1959-06-26 1960-06-20 Process for the production of a colored corrosion-resistant coating on zinc and cadmium

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3518169A (en) * 1965-07-13 1970-06-30 Toyo Kahan Co Ltd Alkali solution treatment of cathodically chromated metal surface
DE10305449A1 (en) * 2003-02-11 2004-08-26 Walter Hillebrand Gmbh & Co. Reaction solution for producing colored passivation film on zinc and its alloys, e.g. on iron or steel, is based on aqueous acid solution containing trivalent chromium ions and contains quinoline dye, preferably quinoline yellow

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2393640A (en) * 1944-11-11 1946-01-29 Rheem Res Products Inc Dyed metals
US2477310A (en) * 1947-07-23 1949-07-26 Clark Thread Co Process and composition for producing a dyeable corrosion resistant surface on zinc and high zinc alloys
GB636954A (en) * 1945-08-23 1950-05-10 Poor & Co Lustrous zinc and method for production thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2393640A (en) * 1944-11-11 1946-01-29 Rheem Res Products Inc Dyed metals
GB636954A (en) * 1945-08-23 1950-05-10 Poor & Co Lustrous zinc and method for production thereof
US2477310A (en) * 1947-07-23 1949-07-26 Clark Thread Co Process and composition for producing a dyeable corrosion resistant surface on zinc and high zinc alloys

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3518169A (en) * 1965-07-13 1970-06-30 Toyo Kahan Co Ltd Alkali solution treatment of cathodically chromated metal surface
DE10305449A1 (en) * 2003-02-11 2004-08-26 Walter Hillebrand Gmbh & Co. Reaction solution for producing colored passivation film on zinc and its alloys, e.g. on iron or steel, is based on aqueous acid solution containing trivalent chromium ions and contains quinoline dye, preferably quinoline yellow

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DE1446513A1 (en) 1969-02-20
GB889184A (en) 1962-02-07

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