GB893771A - Improvements in processes for the production of chemical conversion coatings upon aluminium and its alloys - Google Patents

Improvements in processes for the production of chemical conversion coatings upon aluminium and its alloys

Info

Publication number
GB893771A
GB893771A GB35537/60A GB3553760A GB893771A GB 893771 A GB893771 A GB 893771A GB 35537/60 A GB35537/60 A GB 35537/60A GB 3553760 A GB3553760 A GB 3553760A GB 893771 A GB893771 A GB 893771A
Authority
GB
United Kingdom
Prior art keywords
hexavalent chromium
acid
weight
ferricyanide
hydrofluoric acid
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
Application number
GB35537/60A
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.)
Henkel Corp
Original Assignee
Amchem 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 Amchem Products Inc filed Critical Amchem Products Inc
Publication of GB893771A publication Critical patent/GB893771A/en
Expired 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
    • 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

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)

Abstract

In a process for the production of chemical conversion coatings on aluminium surfaces by treatment with an aqueous acid solution containing hexavalent chromium and a fluorine compound, the solution is replenished by the addition together of hexavalent chromium and one or more of hydrofluoric acid and alkali metal and ammonium fluorides in a ratio of 0,4 to 2 parts by weight of fluoride ion for each part by weight of hexavalent chromium (as CrO3). When the coating solution also contains ferricyanide replenishment of this constituent is effected by the addition of at least 0,05 and preferably 0,2 to 1,0 parts by weight of ferricyanide or ferrocyanide per part of hexavalent chromium. When the fluoride is added exclusively as the alkali metal or ammonium fluoride the weight ratio of fluoride ion to hexavalent chromium is from 0,75 to 1,25 and when added as hydrofluoric acid the ratio should not exceed 0,8 and is preferably 0,5 to 0,75. The pH of the coating solution should preferably be from 1,5 to 1,7 and is controlled by adjusting the proportion of chromic acid and/or hydrofluoric acid to the salts of these acids which are used for replenishment. Any further control is made by adding nitric acid. Examples of coating solutions are given, one consisting of chromic acid, sodium fluohorate, potassium fluozirconate, potassium ferricyanide, and water and the other consisting of chromic acid, potassium ferricyanide, hydrofluoric acid and water. Specifications 735,819, 747,957 and U.S.A. Specifications 2,276,353, 2,507,956 and 2,796,371 are referred to.
GB35537/60A 1959-11-19 1960-10-17 Improvements in processes for the production of chemical conversion coatings upon aluminium and its alloys Expired GB893771A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US854005A US2988465A (en) 1959-11-19 1959-11-19 Method of producing chemical conversion coatings on aluminum surfaces

Publications (1)

Publication Number Publication Date
GB893771A true GB893771A (en) 1962-04-11

Family

ID=25317484

Family Applications (1)

Application Number Title Priority Date Filing Date
GB35537/60A Expired GB893771A (en) 1959-11-19 1960-10-17 Improvements in processes for the production of chemical conversion coatings upon aluminium and its alloys

Country Status (8)

Country Link
US (1) US2988465A (en)
BE (1) BE596469A (en)
CH (1) CH429368A (en)
DE (1) DE1150256B (en)
ES (1) ES258049A1 (en)
FI (1) FI40763B (en)
GB (1) GB893771A (en)
NL (1) NL258036A (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3615740A (en) * 1970-02-02 1971-10-26 Pennwalt Corp Chromate conversion coating compositions containing prusside accelerator
CA1024866A (en) * 1973-04-18 1978-01-24 Yashuhiro Toyoda Colorless chromate coatings for aluminium surfaces
EP0487200B1 (en) * 1990-11-14 2000-06-21 Titeflex Corporation Fluoropolymer aluminium laminate

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2507956A (en) * 1947-11-01 1950-05-16 Lithographic Technical Foundat Process of coating aluminum
BE538540A (en) * 1954-08-05
US2796371A (en) * 1955-03-16 1957-06-18 Allied Res Products Inc Corrosion resistant protective coating on aluminum and aluminum alloys
AT202830B (en) * 1957-08-19 1959-04-10 Metallgesellschaft Ag Process for applying a coating to aluminum surfaces

Also Published As

Publication number Publication date
FI40763B (en) 1969-01-31
DE1150256B (en) 1963-06-12
US2988465A (en) 1961-06-13
ES258049A1 (en) 1960-08-16
BE596469A (en) 1961-02-15
CH429368A (en) 1967-01-31
NL258036A (en)

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