US3857739A - Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium - Google Patents

Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium Download PDF

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Publication number
US3857739A
US3857739A US00285314A US28531472A US3857739A US 3857739 A US3857739 A US 3857739A US 00285314 A US00285314 A US 00285314A US 28531472 A US28531472 A US 28531472A US 3857739 A US3857739 A US 3857739A
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United States
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ion
present
amount
grams per
per litre
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US00285314A
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English (en)
Inventor
M Prust
W Glassman
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.)
ArcelorMittal Dofasco Inc
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Dominion Foundries and Steel Ltd
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Application filed by Dominion Foundries and Steel Ltd filed Critical Dominion Foundries and Steel Ltd
Priority to US00285314A priority Critical patent/US3857739A/en
Priority to CA179,906A priority patent/CA1009549A/en
Priority to AU59773/73A priority patent/AU478974B2/en
Priority to FR7331338A priority patent/FR2198002B1/fr
Priority to JP9815273A priority patent/JPS5652118B2/ja
Priority to DE2343998A priority patent/DE2343998C2/de
Priority to IT52261/73A priority patent/IT990435B/it
Priority to BE135171A priority patent/BE804288A/xx
Priority to GB4116873A priority patent/GB1425380A/en
Application granted granted Critical
Publication of US3857739A publication Critical patent/US3857739A/en
Priority to US05/737,791 priority patent/USRE29827E/en
Assigned to DOFASCO INC. reassignment DOFASCO INC. CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: DOMINION FOUNDRIES AND STEEL LIMITED
Anticipated expiration legal-status Critical
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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
    • C23C22/05—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
    • C23C22/37—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 containing also hexavalent chromium compounds
    • 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 apparatus by which the o r composition is applied to a strip moving through an application station includes a provision for rinsing the [56] References cued surface if the strip is stopped for longer than a prede- UNITED STATES PATENTS termined time in the station.
  • the conversion coating usually is formed by applying a suitable aqueous solution containing chromium to the zinc or cadmium surface, the solution reacting with the surface to form a thin gel-like film of complex chromates.
  • the film is substantially non-porous to moisture, and also is non-crystalline, so that it provides a good paint bond without absorbtion of the paint onto the surface. Examples of processes for producing such a coating are given in US. Pat. Ser. No. 3,457,124, issued July 22nd, 1969 to Cowles Chemical Company, the solution including specified amounts selected from sodium diachromate, chromic acid, sulfamic acid, ammonium sulphate, boric acid, sodium silicofluoride and nitric acid.
  • a composition for producing a chromate protective coating on a surface comprising zinc or cadmium, the composition consisting of an aqueous solution of pH less than 1.15 containing a source of chromium ion, a source of perchlorate ion, the perchlorate ion being present in the amount of 0.5 to 0.85 grams per litre, and a source of fluoride ion, the fluoride ion being present in the amount of 0.1 to 0.27 grams per litre.
  • the chromium ion is the only metallic ion present therein (other than impurities normally present in the technical grade materials used).
  • the pH of the solution may be in the range 1.15 to 0.85, and preferably is in the range 1.0 to 0.9.
  • the chromium ion may be present in the amount of 5 to 15 grams per litre, corresponding to the addition of 10 to 30 grams per litre anhydrous chromium trioxide to the solution, and preferably is present in the amount of 9 to 13 grams of ion per litre.
  • the amount of perchlorate ion present corresponds to the addition of 0.3 to 0.5 ml of percent perchloric acid to each litre of the solution, while the amount of fluoride ion present corresponds to the addition of about 0.1 to 0.25 ml per litre of 48 percent hydrofluoric acid to the solution.
  • the fluoride ion is present in the amount of 0.15 to 0.27 grams per litre.
  • a process in accordance with the present invention includes applying a composition as specified in the preceding two paragraphs to a zinc or cadmium surface for a period of from 1 to 10 seconds at a temperature of from F to 200F.
  • An aqueous solution comprising a composition in accordance with the invention is stored in a tank 14 and fed from there via pump 15, valve 16, pipe 17, automatically controlled valve 18 and header 19 to two sets of spray nozzles 20, which are disposed above and below the strip and direct sprays of the liquid on to the surfaces thereof. Excess liquid that runs from the strip is collected by a catch baisin 21 and returned to the tank 14 via automatically controlled valve 22, valve 23 and pipe 24.
  • a second tank 25 at a higher level than tank 14 contains rinse water which can be fed when required to the spray nozzles 20 via pump 26, pipe 27 and automatically controlled valve 28.
  • the rinse liquid draining from the strip is received by the catch baisin 21 and returned to the tank 25 via an automatically controlled valve 29, valve 30 and pipe 31.
  • the tank 14 is heated and maintained at the required elevated temperature by any convenient means, which are not illustrated, and the tanks 14 and 25 are connected by a pipe 32 and valve 33 to permit the contents of tank 25 to be used as make-up water for the liquid in tank 14 when needed.
  • the contents of tank 25 (the temperature of which may also be controlled if required) are replenished when required from any suitable source of demineralized water via a pipe 34 including valve 35.
  • the strip 10 unwinding from its supply reel passes at substantially constant speed through the station where it is sprayed with liquid from the tank 14. Excess liquid is removed from the strip, and some control of the thickness of the resultant protective coating is provided by the pressure rollers 13, which are pressed intp contact with one another at a predetermined pressure by air-operated motors 36.
  • the speed of movement of the strip, and the distance between the nozzles 20 and the rollers 13, is made such as to give the desired effective immersion time of the strip in the liquid, which typically will be a period of from 1 to 10 seconds.
  • the fact that the strip is moving, and perhaps also the speed at which it is moving through the station 12, is determined by any suitable detector which, in this embodiment, is illustrated as a detector 37 coupled to the rolls 13.
  • the detector controls relay 38 which in turn controls the operation of the valves 18, 22, 28 and 29 and of the pumps and 26.
  • the relay 38 Under normal conditions of operation the relay 38 is operative to maintain the valves 18 and 22 open, the valves 28 and 29 closed, the pump 15 fully operative, and the pump 26 inoperative, or perhaps idling with the pressure relieved by a relief valve 39.
  • the relay 38 Upon the detector 37 sensing that the speed of the strip has dropped below a predetermined value, the relay 38 is operative to close the valves 18 and 22 and stop the pump 15, cutting off the supply of the liquid from the tank 14.
  • valves 28 and 29 are opened and the pump 26 operated to supply rinse water to the nozzles and rinse the liquid from the strip, thereby preventing excessive exposure of that part of the strip to the effect of the liquid, which usually will render it unfit for commercial usage because of discolouration. Normal operation will be resumed when the strip again is moving at above the minimum speed.
  • the length of the abovementioned period is such as to permit normal short stoppage of the line without operation of the rinse apparatus.
  • the control of the pressure applied to the strip by the rollers 13 is found to be important in obtaining the desired results, and will be discussed in detail below. It is found necessary in practice to change the rolls relatively frequently as they become worn and to re-work them to the required profile, while will change the weight of the rolls thus altering the pressure control characteristic. This effect is avoided in apparatus in accordance with the invention by providing that the pressure motors 36 are double-acting cylinders, the upper and lower parts of the cylinder being fed independently with compressed air from pipes 40 and 41 including valves 42 and 43 respectively.
  • the essential constituents of the aqueous coating composition of the present invention are a source of chromium ion, a source of perchlorate ion, and a source of fluoride ion, the chromium ion being the only metallic ion present therein.
  • ammonium and like complex ions e.g. H is not a complex ion
  • metallic ions are regarded as metallic ions.
  • the pH value of the solution is made less than ].l5 and preferably is in the range of 0.9 to 1.0, with a preferred minimum of 0.8.
  • composition does not contain a buffering agent or agents, the most common of which are usually solid materials with a tendency to form insoluble compounds that will settle as sludge.
  • buffering agent or agents the most common of which are usually solid materials with a tendency to form insoluble compounds that will settle as sludge.
  • the avoidance of sludge deposits is of course important in a commercial system to avoid the need for elaborate filter arrangements and to prevent blocking of the pipes by sludge particles, etc.
  • the chromium ion is supplied to the solution most conveniently in the form of anhydrous chromium trioxide, in which the chromium is in hexavalent form.
  • This compound can constitute a convenient medium for specifying the required concentration of the chromium in the solution, which should be present as ion in the amount of 5 to 15 grams per litre, preferably 9 to 13 grams per litre.
  • the corresponding quantities of the trioxide to be added are 10 to 30 grams per litre, preferably 18 to 25 grams per litre. The calculation of any other suitable material added to the solution will be apparent to those skilled in the art.
  • the perchlorate is added in the form of 60 percent perchloric acid to provide the required amount of ion of 0.5 to 0.85 grams per litre, and for this concentration the solution should contain from 0.3 to 0.5 ml per litre of the said 60 percent perchloric acid.
  • the fluoride ion conveniently is added as 48 percent hydrofluoric acid to provide from 0.1 to 0.27 grams per litre of the fluoride ion, preferably 0.l5 to 0.27 grams per litre, and this amount of ion requires the addition of about 0.1 to 0.25 ml per litre of the acid, preferably 0.15 to 0.25 ml per litre.
  • the usable operating temperature range for the solution is l50F to 200F, while the preferred temperature range is lF to F.
  • the time of application is of the order of l to l0 seconds only, and the provision for rinsing described above is made operative if the exposure time increases to above fifteen seconds.
  • An excessive exposure time is indicated by brown discolouration and even etching of the zinc surface.
  • composition solution in contact with the zinc or cadmium surface generates hydrogen which is believed to reduce some of the hexavalent chromium to trivalent chromium, some of which may then be oxidised by the perchlorate ion back to the hexavalent state to balance the relative concentrations in the solution.
  • the balance of the trivalent chromium goes into film formation on the zinc or cadmium surface.
  • the trivalent chromium is believed more effective than the hexavalent form in combining with the fluoride ion, with which it complexes readily during film formation.
  • An examination of typical films produced shows trivalent chromium in the amount of from about 5 to about 12 micrograms per sq. inch (m.s.i.) while the hexavalent form is present in the amount of from about 2 to about 7 m.s.i., giving a total chromium content of from about 7 to about 19 m.s.i., most usually in the neighbourhood of about 16 m.s.i. This thickness may be compared to the usual thickness of about 9 m.s.i. obtained with known systems. Excellent results have also been achieved with film weight outside these values.
  • the films produced by the application of the invention are found to be unexpectedly much more protective than those of known prior methods.
  • One test known as the humidity cabinet test involves the use of a Cleveland condensation tester cabinet having its interior maintained at 100F, wherein strips of galvanized steel are suspended above a water trough, the side exposed to the trough being at the said temperature of 100F, while the other side is at the ambient tempera ture, usually about 70F.
  • the humidity of the cabinet interior is 100 percent and the water that condenses on the inner surface trickles back into the trough, giving the effect of a constant exposure to a rainy atmosphere.
  • the strips are maintained under this condition until visual inspection shows that about 10 percent of the zinc coating has corroded to white rust.
  • an average exposure of 30 hours was sufficient to produce the specified corrosion, while this degree of attack is only obtained with the processes etc. of this invention after an exposure of about 400 1,000 hours.
  • the hexavalent chromium is considerably more mobile in the film forming complexes than the trivalent form, in addition to being more soluble, and does operate to provide a sealing" mechanism whereby the mobile hexavalent ion migrates to potential holes in the film and reacts readily with the zinc to close such holes.
  • the trivalent form complexed with the zinc and the fluorine that provides the essential protective film.
  • the excess solution removed by the pressure rolls has the chromium predominantly in the hexavalent form because of its higher solubility and concentration.
  • a composition for producing a chromate protective coating on a surface comprising zinc or cadmium, the composition consisting of an aqueous solution of pH less than 1.15 containing a source of chromium ion, the chromium ion being present in the amount of 5-15 grams per liter, a source of perchlorate ion, the perchlorate ion being present in the amount of 0.5 to 0.85 grams per litre, and a source of fluoride ion, the fluoride ion being present in the amount of 0.1 to 0.27 grams per litre.
  • composition as claimed in claim 1 wherein the pH of the solution is in the range 1.15 to 0.85.
  • composition as claimed in claim 1 wherein the fluoride ion is present in the amount of 0.15 to 0.27 grams per litre.
  • a process for producing a conversion coating on a metal surface comprising zinc or cadmium including applying to the surface for a period of from 1 to 10 seconds at a temperature of from F to 200F a composition consisting of an aqueous solution of pH in the range 1.0 to 0.9 containing a source of chromium ion, the chromium ion being present in the amount of 5-15 grams per liter, a source of perchlorate ion, the perchlorate ion being present in the amount of 0.5 to 0.85 grams per litre, and a source of fluoride ion, the fluoride ion being present in the amount of 0.1 to 0.27 grams per litre.
  • a process for producing a conversion coating on a metal surface comprising zinc or cadmium including applying to the surface for a period of from 1 to 10 seconds at a temperature of from 150F to 200F a composition containing an aqueous solution of pH less than 1.15 containing a source of chromium ion, the chromium ion being present in the amount of to 15 grams per litre, a source of perchlorate ion, the perchlorate ion being present in the amount of 0.5 to 0.85 grams per litre, and a source of fluoride ion, the fluoride ion being present in the amount of 0.1 to 0.27 grams per litre.
  • a process for producing a conversion coating on a metal surface comprising zinc or cadmium including applying to the surface for a period of from 1 to 10 seconds at a temperature of from 150F to 200F a composition consisting of an aqueous solution of pH less than 1.15 containing a source of chromium ion, the chromium ion being present in the amount of9 to 13 grams per litre, a source of perchlorate ion, the perchlorate ion being present in the amount of 0.5 to 0.85 grams per litre, and a source of fluoride ion, the fluoride ion being present in the amount of 0.1 to 0.27 grams per litre.
  • a process for producing a conversion coating on a metal surface comprising zinc or cadmium including applying to the surface for a period of from 1 to 10 seconds at a temperature of from 150F to 200F a compo sition consisting of an aqueous solution of pH less than 1.15 containing a source of chromium ion, the chromium ion being present in the amount of 5-15 grams per liter, a source of perchlorate ion, the perchlorate ion being present in the amount of 0.5 to 0.85 grams per litre, and a source of fluoride ion, the fluoride ion being present in the amount of 0.15 to 0.27 grams per litre.
  • a process for producing a conversion coating on a metal surface comprising zinc or cadmium including applying to the surface for a period of from 1 to 10 seconds at a temperature of from F to 200F a composition consisting of an aqueous solution wherein the pH of the solution is in the range 1.15 to 0.85, chromium ion is present in the amount of 5 to 15 grams per litre, perchlorate ion is present in the amount of 0.5 to 0.85 grams per litre, and fluoride ion is present in the amount of 0.1 to 0.27 grams per litre.
  • a process for producing a conversion coating on a metal surface comprising zinc or cadmium including applying to the surface for a period of from 1 to 10 seconds at a temperature of from F to F a composition consisting of an aqueous solution wherein the pH of the solution is in the range 1.0 to 0.9, chromium ion is present in the amount of 9 to 13 grams per litre, perchlorate ion is present in the amount of 0.5 to 0.85 grams per litre and fluoride ion is present in the amount

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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)
  • Inorganic Compounds Of Heavy Metals (AREA)
US00285314A 1972-08-31 1972-08-31 Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium Expired - Lifetime US3857739A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US00285314A US3857739A (en) 1972-08-31 1972-08-31 Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium
CA179,906A CA1009549A (en) 1972-08-31 1973-08-29 Compositions and processes for producing chromium conversion coatings
AU59773/73A AU478974B2 (en) 1972-08-31 1973-08-29 Compositions and processes for producing chromium conversion coatings
FR7331338A FR2198002B1 (de) 1972-08-31 1973-08-30
DE2343998A DE2343998C2 (de) 1972-08-31 1973-08-31 Wässrige Chromatierlösung und Verfahren zur Herstellung eines Chromatschutzüberzuges auf Zink- oder Cadmiumoberflächen
IT52261/73A IT990435B (it) 1972-08-31 1973-08-31 Composizione e procedimento per l applicazione di rivestimenti protettivi su superfici
JP9815273A JPS5652118B2 (de) 1972-08-31 1973-08-31
BE135171A BE804288A (fr) 1972-08-31 1973-08-31 Compositions et procedes pour la production de couches de chrome sur des surfaces de zinc ou de cadmium
GB4116873A GB1425380A (en) 1972-08-31 1973-08-31 Compositions and processes for producing chromium conversion coa tings
US05/737,791 USRE29827E (en) 1972-08-31 1976-11-01 Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00285314A US3857739A (en) 1972-08-31 1972-08-31 Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US05/737,791 Reissue USRE29827E (en) 1972-08-31 1976-11-01 Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium

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US00285314A Expired - Lifetime US3857739A (en) 1972-08-31 1972-08-31 Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium
US05/737,791 Expired - Lifetime USRE29827E (en) 1972-08-31 1976-11-01 Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium

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US05/737,791 Expired - Lifetime USRE29827E (en) 1972-08-31 1976-11-01 Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium

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US (2) US3857739A (de)
JP (1) JPS5652118B2 (de)
BE (1) BE804288A (de)
CA (1) CA1009549A (de)
DE (1) DE2343998C2 (de)
FR (1) FR2198002B1 (de)
GB (1) GB1425380A (de)
IT (1) IT990435B (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE29827E (en) * 1972-08-31 1978-11-07 Dominion Foundries And Steel, Limited Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium
US4126490A (en) * 1978-05-01 1978-11-21 Caterpillar Mitsubishi Ltd. Composition for forming chromate coating
US4141758A (en) * 1977-01-14 1979-02-27 Dominion Foundries And Steel, Limited Compositions and processes for producing chromium conversion coatings on surfaces of zinc/iron alloy
US6287704B1 (en) 1996-04-19 2001-09-11 Surtec Produkte Und System Fur Die Oberflachenbehandlung Gmbh Chromate-free conversion layer and process for producing the same
US7314671B1 (en) 1996-04-19 2008-01-01 Surtec International Gmbh Chromium(VI)-free conversion layer and method for producing it
US20110070429A1 (en) * 2009-09-18 2011-03-24 Thomas H. Rochester Corrosion-resistant coating for active metals
US20110151126A1 (en) * 2008-08-29 2011-06-23 Metts Glenn A Trivalent chromium conversion coating

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4171231A (en) * 1978-04-27 1979-10-16 R. O. Hull & Company, Inc. Coating solutions of trivalent chromium for coating zinc surfaces
US5219617A (en) * 1989-09-19 1993-06-15 Michigan Chrome And Chemical Company Corrosion resistant coated articles and process for making same

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2106227A (en) * 1935-04-29 1938-01-25 Allegheny Steel Co Surface treatment of metal to prevent localized corrosive attack
US2786002A (en) * 1954-04-28 1957-03-19 American Chem Paint Co Method of treating zinciferous surfaces
US3116176A (en) * 1959-05-14 1963-12-31 Raymond Druckknopf & Metallwar Process for the production of corrosionresistant coatings on zinc- and cadmium-surfaces
US3287179A (en) * 1963-01-04 1966-11-22 Frank Theodore Process for preparing aluminum surfaces prior to plating
US3331710A (en) * 1963-08-23 1967-07-18 Hooker Chemical Corp Method for coating aluminum
US3481797A (en) * 1966-08-17 1969-12-02 Hooker Chemical Corp Method for operating chemical processing solutions
US3620777A (en) * 1968-07-24 1971-11-16 Hooker Chemical Corp Chromate chemical coating solution for zinc alloy
US3706604A (en) * 1971-01-20 1972-12-19 Oxy Metal Finishing Corp Process for the coating of metal

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU412989B2 (en) * 1967-04-20 1971-05-04 John Lysaght (Australia) Limited Composition and process for inhibiting corrosion of zinc surfaces
US3660172A (en) * 1970-08-19 1972-05-02 Amchem Prod Prepaint treatment for zinciferous surfaces
US3752707A (en) * 1971-08-23 1973-08-14 Heatbath Corp Corrosion resistant composition and method
US3857739A (en) * 1972-08-31 1974-12-31 Dominion Foundries & Steel Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2106227A (en) * 1935-04-29 1938-01-25 Allegheny Steel Co Surface treatment of metal to prevent localized corrosive attack
US2786002A (en) * 1954-04-28 1957-03-19 American Chem Paint Co Method of treating zinciferous surfaces
US3116176A (en) * 1959-05-14 1963-12-31 Raymond Druckknopf & Metallwar Process for the production of corrosionresistant coatings on zinc- and cadmium-surfaces
US3287179A (en) * 1963-01-04 1966-11-22 Frank Theodore Process for preparing aluminum surfaces prior to plating
US3331710A (en) * 1963-08-23 1967-07-18 Hooker Chemical Corp Method for coating aluminum
US3481797A (en) * 1966-08-17 1969-12-02 Hooker Chemical Corp Method for operating chemical processing solutions
US3620777A (en) * 1968-07-24 1971-11-16 Hooker Chemical Corp Chromate chemical coating solution for zinc alloy
US3706604A (en) * 1971-01-20 1972-12-19 Oxy Metal Finishing Corp Process for the coating of metal

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE29827E (en) * 1972-08-31 1978-11-07 Dominion Foundries And Steel, Limited Compositions and processes for producing chromium conversion coatings on surfaces of zinc or cadmium
US4141758A (en) * 1977-01-14 1979-02-27 Dominion Foundries And Steel, Limited Compositions and processes for producing chromium conversion coatings on surfaces of zinc/iron alloy
US4126490A (en) * 1978-05-01 1978-11-21 Caterpillar Mitsubishi Ltd. Composition for forming chromate coating
US6287704B1 (en) 1996-04-19 2001-09-11 Surtec Produkte Und System Fur Die Oberflachenbehandlung Gmbh Chromate-free conversion layer and process for producing the same
US6946201B2 (en) 1996-04-19 2005-09-20 Surtec International Gmbh Chromium (VI)-free conversion layer and method for producing it
US7314671B1 (en) 1996-04-19 2008-01-01 Surtec International Gmbh Chromium(VI)-free conversion layer and method for producing it
US20110151126A1 (en) * 2008-08-29 2011-06-23 Metts Glenn A Trivalent chromium conversion coating
US20110070429A1 (en) * 2009-09-18 2011-03-24 Thomas H. Rochester Corrosion-resistant coating for active metals

Also Published As

Publication number Publication date
DE2343998A1 (de) 1974-03-07
JPS4991933A (de) 1974-09-03
GB1425380A (en) 1976-02-18
IT990435B (it) 1975-06-20
BE804288A (fr) 1973-12-17
DE2343998C2 (de) 1983-05-11
AU5977373A (en) 1975-03-06
FR2198002B1 (de) 1978-01-27
CA1009549A (en) 1977-05-03
JPS5652118B2 (de) 1981-12-10
FR2198002A1 (de) 1974-03-29
USRE29827E (en) 1978-11-07

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