US2799601A - Composition and method for coating zinc and zinc alloy sheets - Google Patents

Composition and method for coating zinc and zinc alloy sheets Download PDF

Info

Publication number
US2799601A
US2799601A US503327A US50332755A US2799601A US 2799601 A US2799601 A US 2799601A US 503327 A US503327 A US 503327A US 50332755 A US50332755 A US 50332755A US 2799601 A US2799601 A US 2799601A
Authority
US
United States
Prior art keywords
zinc
water soluble
group
soluble salts
solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US503327A
Inventor
Harry J Hartman
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.)
Allied Res Products Inc
Original Assignee
Allied Res Products 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 Allied Res Products Inc filed Critical Allied Res Products Inc
Priority to US503327A priority Critical patent/US2799601A/en
Application granted granted Critical
Publication of US2799601A publication Critical patent/US2799601A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/24—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 hexavalent chromium compounds

Definitions

  • This invention relates to the treatment of zinc or alloys thereof and is used for coating purposes on strip line operations such as mill, hot-galvanized or acid-zinc sheets.
  • the principal object of the invention is to impart a clear protective surface or film, having improved corrosion resistance, on zinc or zinc alloy used in strip line operation by subjecting the surface of the strip being treated to immersion in a filming bath.
  • Another and more specific object of the invention is to provide a clear protective film on a zinc or zinc alloy coating used for mill, hot-galvanized and acid-zinc sheets thus preventing discoloring, e. g., white bloom, which normally forms during storage by the highly corrosive action of the zinc or zinc alloy under moisture conditions, particularly when sheets are stacked one on another.
  • Another object of the invention is to provide a treating solution and method which will enable the above mentioned result's to be uniformly obtained on a commercial scale.
  • An additional object of my invention is to provide a composition for use in aqueous acidic solution to impart a clear protective coating to zinc and zinc alloy coated mill-galvanized sheets
  • a composition for use in aqueous acidic solution to impart a clear protective coating to zinc and zinc alloy coated mill-galvanized sheets comprising at least one chromic compound selected from the group consisting of chromic acid and water soluble salts thereof, at least one boric compound selected from the group consisting of boric acid and water soluble salts thereof, at least one chloride containing compound selected from the group consisting of hydrochloric acid and water soluble salts thereof and a nitrate containing compound, selected from the group consisting of nitric acid and water soluble salts thereof all ingredients being of sufiicient strength and quantity to adjust the pH of the resulting solution to between about 0.2 and 4.0.
  • Still another object of my invention is to provide a composition as set forth heretofore wherein said chromic compound is in amount equivalent to from about 3 to 100 grams of sodium bichromate per liter of solution, the boric compound is an amount equivalent to from about 1 to 35 grams of boric acid per liter of solution, the water soluble chloride is in amount of 0.1 to 20 grams per liter of solution, and nitric acid in amount sufficient to maintain a pH of solution of about 0.2 to 4.0.
  • the three dry constituents of the foregoing example are dissolved in water, preferably lukewarm, and the nitric acid added until a pH of about 0.4 is attained. Then, if desired, the wetting agent mentioned or any suitable commercially available agent is added to avoid the possibility of water break on the surfaces to which the solution is applied.
  • the product of the above example is used successfully in amount of about 3 ounces per gallon of water, and within a range of about 2.5 to 20 ounces per gallon of water.
  • the sheet to be treated is sprayed or immersed in the solution having a temperature of about to 200 F. for 1 second to 30 seconds. The higher the temperature and longer the time of immersion, the greater the reaction and the more color imparted to the sheet.
  • a good passivation temperature for the bath is 170 F. and the immersion time is 4 seconds.
  • a good treatment is provided by immersing the sheet in a bath at about 70 F., room temperature, for 15 seconds. Both treatments produce satisfactory corrosion resistance and passivation.
  • the sodium bichromate plus the chloride activator produce a protective film when buifer supplied by the boric acid and the pH adjusted by the nitric acid are in correct balance.
  • the pH of the treating solution may vary between about .2 and 4.0, the solution of the foregoing example being preferably used at a pH of 1.4 or a pH maintained between about 1.4 and 1.5 for good passivation and when more color is desired, the pH is lowered, i. e., .2 to 1.4, which affords increased protection as indicated by the increased yellow or irridescent film.
  • 1 mean a surface to be passivated and rendered corrosion resistant having its entire area or a substantial area, of zinc or zinc alloy.
  • sodium bichromate may be substituted by other equivalent chromium compounds in equivalent amounts notably chromic acid and (2) that boric acid may be substituted by other equivalent boron containing compounds in equivalent amount notably sodium or potassium borate, and each within the ranges recited above.
  • boric acid may be substituted by other equivalent boron containing compounds in equivalent amount notably sodium or potassium borate, and each within the ranges recited above.
  • sodium chloride may be substituted by its equivalent hydrochloric acid, potassium chloride and other chlorides as recited above.
  • Sodium nitrate may be substituted as an equivalent for nitric acid, both for the purpose described herein and in amounts to accomplish similar functions, within the ranges recited above.
  • wetting agent is preferred but is optional, any suitable agent being used.
  • An aqueous acidic solution for passivating and im proving corrosion resistance of zinc surfaces comprising 3 to g./l. NazGrzOmZHzO; 1 to 35 g./l. HsBOs; 0.1 to 20 g./l. NaCl; and 1 to 10 ml./l. HNO (42 B.).
  • An aqueous acidic solution for passivating and improving corrosion resistance of zinc surfaces comprising 10 g./l. NazCrzOmZHzO; 10 g./l. H3BO3; 2.3 g./l. NaCl; and 1 mL/l. HNO3(42 B.).
  • a solution according to claim 1 having a pH between about 0.2 and 4.
  • a process for passivating and improving the corrosion resistance of zinc surfaces comprising subjecting the same to an aqueous acidic solution comprising 3 to 100 g./l. Na2C1'2O'z.2H2O; 1 to 35 g./l. HaBOs; 0.1 to 20 g./1. NaCl; and 1 to 10 m1./l. HNOa (42 B.), for
  • An aqueous acidic solution for passivating and improving c'orrosio-n resistance of zinc surfaces comprising 1) a member of the group consisting of chromic acid and water soluble salts thereof in an amount equivalent to 3 to 100 g./l. NazCrzOmZHzO; (2) a member of the group consisting of boric acid and water soluble salts thereof in an amount equivalent to 1 to 35 g./l. of HaBOa; (3) a member of the group consisting of hydrochloric acid and Water soluble salts thereof in an amount equivalent to 0.1 to 20 g./l. NaCl, and (4) a member of the group consisting of nitric acid and water soluble salts thereof in an amount equivalent to 1 to 10 ml./l. HNO3 (42 B.), said solution having a pH between about 0.2 and 4.

Landscapes

  • 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 Patent O COMPOSITION AND METHOD FOR COATING ZINC AND ZINC ALLOY SHEETS Harry J. Hartman, Baltimore, Md., assignor to Allied Research Products, Inc., Baltimore, Md., a corporation of Maryland No Drawing. Application April 22, 1955, Serial No. 503,327
Claims. (Cl. 1486.2)
This invention relates to the treatment of zinc or alloys thereof and is used for coating purposes on strip line operations such as mill, hot-galvanized or acid-zinc sheets.
The principal object of the invention is to impart a clear protective surface or film, having improved corrosion resistance, on zinc or zinc alloy used in strip line operation by subjecting the surface of the strip being treated to immersion in a filming bath.
Another and more specific object of the invention is to provide a clear protective film on a zinc or zinc alloy coating used for mill, hot-galvanized and acid-zinc sheets thus preventing discoloring, e. g., white bloom, which normally forms during storage by the highly corrosive action of the zinc or zinc alloy under moisture conditions, particularly when sheets are stacked one on another.
Another object of the invention is to provide a treating solution and method which will enable the above mentioned result's to be uniformly obtained on a commercial scale.
An additional object of my invention is to provide a composition for use in aqueous acidic solution to impart a clear protective coating to zinc and zinc alloy coated mill-galvanized sheets comprising at least one chromic compound selected from the group consisting of chromic acid and water soluble salts thereof, at least one boric compound selected from the group consisting of boric acid and water soluble salts thereof, at least one chloride containing compound selected from the group consisting of hydrochloric acid and water soluble salts thereof and a nitrate containing compound, selected from the group consisting of nitric acid and water soluble salts thereof all ingredients being of sufiicient strength and quantity to adjust the pH of the resulting solution to between about 0.2 and 4.0.
Still another object of my invention is to provide a composition as set forth heretofore wherein said chromic compound is in amount equivalent to from about 3 to 100 grams of sodium bichromate per liter of solution, the boric compound is an amount equivalent to from about 1 to 35 grams of boric acid per liter of solution, the water soluble chloride is in amount of 0.1 to 20 grams per liter of solution, and nitric acid in amount sufficient to maintain a pH of solution of about 0.2 to 4.0.
The following preferred formulation has been found to provide a clear colorless finish in actual strip line operation and to eliminate discoloring, e. g., white bloom, during normal storage and, in addition, impart desirable resistance to corrosion produced by a salt atmosphere and as observed by standard test on salt spray testing apparatus:
2,799,601 Patented July 16, 1957 The foregoing composition will promote passivation and corrosion resistance on mill, hot-galvanized and acidzinc sheets.
The three dry constituents of the foregoing example are dissolved in water, preferably lukewarm, and the nitric acid added until a pH of about 0.4 is attained. Then, if desired, the wetting agent mentioned or any suitable commercially available agent is added to avoid the possibility of water break on the surfaces to which the solution is applied.
The product of the above example is used successfully in amount of about 3 ounces per gallon of water, and within a range of about 2.5 to 20 ounces per gallon of water.
The sheet to be treated is sprayed or immersed in the solution having a temperature of about to 200 F. for 1 second to 30 seconds. The higher the temperature and longer the time of immersion, the greater the reaction and the more color imparted to the sheet. A good passivation temperature for the bath is 170 F. and the immersion time is 4 seconds. Also a good treatment is provided by immersing the sheet in a bath at about 70 F., room temperature, for 15 seconds. Both treatments produce satisfactory corrosion resistance and passivation.
The sodium bichromate plus the chloride activator produce a protective film when buifer supplied by the boric acid and the pH adjusted by the nitric acid are in correct balance.
The pH of the treating solution may vary between about .2 and 4.0, the solution of the foregoing example being preferably used at a pH of 1.4 or a pH maintained between about 1.4 and 1.5 for good passivation and when more color is desired, the pH is lowered, i. e., .2 to 1.4, which affords increased protection as indicated by the increased yellow or irridescent film.
In referring in the appended claims to zinc surfaces, 1 mean a surface to be passivated and rendered corrosion resistant having its entire area or a substantial area, of zinc or zinc alloy.
It is also tobe understood (1) that sodium bichromate may be substituted by other equivalent chromium compounds in equivalent amounts notably chromic acid and (2) that boric acid may be substituted by other equivalent boron containing compounds in equivalent amount notably sodium or potassium borate, and each within the ranges recited above. Similarly sodium chloride may be substituted by its equivalent hydrochloric acid, potassium chloride and other chlorides as recited above. Sodium nitrate may be substituted as an equivalent for nitric acid, both for the purpose described herein and in amounts to accomplish similar functions, within the ranges recited above.
The use of a wetting agent is preferred but is optional, any suitable agent being used.
I claim:
l. An aqueous acidic solution for passivating and im proving corrosion resistance of zinc surfaces comprising 3 to g./l. NazGrzOmZHzO; 1 to 35 g./l. HsBOs; 0.1 to 20 g./l. NaCl; and 1 to 10 ml./l. HNO (42 B.).
2. An aqueous acidic solution for passivating and improving corrosion resistance of zinc surfaces comprising 10 g./l. NazCrzOmZHzO; 10 g./l. H3BO3; 2.3 g./l. NaCl; and 1 mL/l. HNO3(42 B.).
3. A solution according to claim 1 having a pH between about 0.2 and 4.
4. A process for passivating and improving the corrosion resistance of zinc surfaces comprising subjecting the same to an aqueous acidic solution comprising 3 to 100 g./l. Na2C1'2O'z.2H2O; 1 to 35 g./l. HaBOs; 0.1 to 20 g./1. NaCl; and 1 to 10 m1./l. HNOa (42 B.), for
perature of about 70 F. to 200 F. and a pH of about 5. An aqueous acidic solution for passivating and improving c'orrosio-n resistance of zinc surfaces comprising 1) a member of the group consisting of chromic acid and water soluble salts thereof in an amount equivalent to 3 to 100 g./l. NazCrzOmZHzO; (2) a member of the group consisting of boric acid and water soluble salts thereof in an amount equivalent to 1 to 35 g./l. of HaBOa; (3) a member of the group consisting of hydrochloric acid and Water soluble salts thereof in an amount equivalent to 0.1 to 20 g./l. NaCl, and (4) a member of the group consisting of nitric acid and water soluble salts thereof in an amount equivalent to 1 to 10 ml./l. HNO3 (42 B.), said solution having a pH between about 0.2 and 4.
References Cited in the file of this patent UNITED STATES PATENTS Dennis Oct. 13, Wetherbee Oct. 29, Wilhelm Mar. 24, Wilhelm Feb. 1, Romig Apr. 12, Michel Nov. 1, Buzzard June 11, Ott Apr. 4,
OTHER REFERENCES Britton, Hydrogen Ions, page 286, Table 81. Goldowski, Abstract of application Serial No. 619,264, published April 29, 1952, 657 O. G. 1582. v

Claims (1)

  1. 5. AN AQUEOUS ACIDIC SOLUTION FOR PASSIVATING AND IMPROVING CORROSION RESISTANCE OF ZINC SURFACES COMPRISING (1) A MEMBER OF THE GROUP CONSISTING OF CHROMIC ACID AND WATER SOLUBLE SALTS THEREOF IN AN AMOUNT EQUIVALENT TO 3 TO 100 G./1. NA2CR2O72H2O; (2) A MEMBER OF THE GROUP CONSISTING OF BORIC ACID AND WATER SOLUBLE SALTS THEREOF IN AN AMOUNT EQUIVALENT TO 1 TO 35 G./1. OF H3BO3; (3) A MEMBER OF THE GROUP CONSISTING OF HYDROCHLORIC ACID AND WATER SOLUBLE SALTS THEREOF IN AN AMOUNT EQUIVALENT TO 0.1 TO 20 G./1. NAC1, AND (4) A MEMBER OF THE GROUP CONSISTING OF NITRIC ACID AND WATER SOLUBLE SALTS THEREOF IN AN AMOUNT EQUIVALENT TO 1 TO 10 ML./1. HNO3 (42*BE), SAID SOLUTION HAVING A PH BETWEEN ABOUT 0.2 AND 4.
US503327A 1955-04-22 1955-04-22 Composition and method for coating zinc and zinc alloy sheets Expired - Lifetime US2799601A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US503327A US2799601A (en) 1955-04-22 1955-04-22 Composition and method for coating zinc and zinc alloy sheets

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US503327A US2799601A (en) 1955-04-22 1955-04-22 Composition and method for coating zinc and zinc alloy sheets

Publications (1)

Publication Number Publication Date
US2799601A true US2799601A (en) 1957-07-16

Family

ID=24001629

Family Applications (1)

Application Number Title Priority Date Filing Date
US503327A Expired - Lifetime US2799601A (en) 1955-04-22 1955-04-22 Composition and method for coating zinc and zinc alloy sheets

Country Status (1)

Country Link
US (1) US2799601A (en)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1827223A (en) * 1928-02-02 1931-10-13 Clark M Dennis Treatment of iron and steel
US2018694A (en) * 1934-05-14 1935-10-29 Benton H Grant Process of treating aluminum surfaces
US2035380A (en) * 1933-05-13 1936-03-24 New Jersey Zinc Co Method of coating zinc or cadmium base metals
US2106904A (en) * 1936-02-21 1938-02-01 New Jersey Zinc Co Coating malleable non-noble heavy metals
US2114151A (en) * 1935-07-09 1938-04-12 American Chem Paint Co Art of finishing ferrous metal
US2134830A (en) * 1936-09-04 1938-11-01 Magnesium Dev Corp Process of producing corrosion resistant coatings on magnesium and high percentage magnesium alloys
US2203670A (en) * 1937-06-29 1940-06-11 Robert W Buzzard Method of treating electrolytic coatings on magnesium and its alloys
US2502476A (en) * 1948-06-02 1950-04-04 Rheem Mfg Co Producing transparent protective films on zinc or cadmium

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1827223A (en) * 1928-02-02 1931-10-13 Clark M Dennis Treatment of iron and steel
US2035380A (en) * 1933-05-13 1936-03-24 New Jersey Zinc Co Method of coating zinc or cadmium base metals
US2018694A (en) * 1934-05-14 1935-10-29 Benton H Grant Process of treating aluminum surfaces
US2114151A (en) * 1935-07-09 1938-04-12 American Chem Paint Co Art of finishing ferrous metal
US2106904A (en) * 1936-02-21 1938-02-01 New Jersey Zinc Co Coating malleable non-noble heavy metals
US2134830A (en) * 1936-09-04 1938-11-01 Magnesium Dev Corp Process of producing corrosion resistant coatings on magnesium and high percentage magnesium alloys
US2203670A (en) * 1937-06-29 1940-06-11 Robert W Buzzard Method of treating electrolytic coatings on magnesium and its alloys
US2502476A (en) * 1948-06-02 1950-04-04 Rheem Mfg Co Producing transparent protective films on zinc or cadmium

Similar Documents

Publication Publication Date Title
US2796370A (en) Composition and method for producing corrosion resistant protective coating on aluminum and aluminum alloys
US2499261A (en) Compositions and methods for depositing amorphous metal-phosphate coatings on metal surfaces
US3929514A (en) Composition and method for forming a protective coating on a zinc metal surface
US2121574A (en) Art of coating zinc
US2462196A (en) Protective phosphate coatings for metal surfaces
JPH0331790B2 (en)
US3895969A (en) Composition and process for inhibiting corrosion of non-ferrous metal surfaced articles and providing surface for synthetic resin coating compositions
DE2061773A1 (en) Process for soldering work pieces made of stainless steel with work pieces made of aluminum or aluminum alloys
US3395052A (en) Pretreating process for phosphatetreating steel sheets and plated steel sheets
US2799601A (en) Composition and method for coating zinc and zinc alloy sheets
US3752708A (en) Corrosion resistant composition and method
US2784122A (en) Process of retarding corrosion of coated metal articles and coated metal article
US3398010A (en) Masking composition for galvanized metal
JPS6256579A (en) Acidic aqueous solution and method for passivating surface of zinc or zinc/aluminum alloy
US2902348A (en) Testing material
US3752707A (en) Corrosion resistant composition and method
US2502476A (en) Producing transparent protective films on zinc or cadmium
US3447972A (en) Process and compositions for producing aluminum surface conversion coatings
US4812175A (en) Passivation process and copmposition for zinc-aluminum alloys
US1961030A (en) Process for protecting magnesium and its alloys against corrosion
US3620939A (en) Coating for magnesium and its alloys and method of applying
US3907612A (en) Preanneal rinse process for inhibiting pin point rust
US2628925A (en) Bright corrosion resistant coating of metals
US3007818A (en) Protective coatings on metals
US2843513A (en) Mixture and method for imparting a corrosion-resistant surface to aluminum, aluminumalloys, and silver