EP0087288A1 - Bath and method for black chromate plating of zinc and cadmium surfaces - Google Patents

Bath and method for black chromate plating of zinc and cadmium surfaces Download PDF

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Publication number
EP0087288A1
EP0087288A1 EP83300852A EP83300852A EP0087288A1 EP 0087288 A1 EP0087288 A1 EP 0087288A1 EP 83300852 A EP83300852 A EP 83300852A EP 83300852 A EP83300852 A EP 83300852A EP 0087288 A1 EP0087288 A1 EP 0087288A1
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EP
European Patent Office
Prior art keywords
ions
bath
zinc
plating
chromium
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.)
Withdrawn
Application number
EP83300852A
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German (de)
French (fr)
Inventor
Eliane Jeannier
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M&T Chemicals Inc
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M&T Chemicals Inc
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Publication of EP0087288A1 publication Critical patent/EP0087288A1/en
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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
    • C23C22/82—After-treatment
    • C23C22/83—Chemical after-treatment
    • 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
    • C23C22/26—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 containing also organic compounds
    • C23C22/27—Acids
    • 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
    • C23C22/30—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 containing also trivalent chromium
    • 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
    • C23C22/40—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 molybdates, tungstates or vanadates
    • C23C22/43—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 molybdates, tungstates or vanadates containing also hexavalent chromium compounds

Definitions

  • the present invention relates to new bath permitting, by chromium plating, to obtain a shiny black coating on surfaces of zinc, or zinc-or cadmium-containing alloys.
  • solutions used to this effect contain essentially chromium (for example in sodium or potassium dichromate and or chromic acid form), sulphate ions and, in some cases a metallic compound giving rise to the formation of a suitably coloured chromate deposit.
  • chromium for example in sodium or potassium dichromate and or chromic acid form
  • sulphate ions for example in sodium or potassium dichromate and or chromic acid form
  • metallic compound giving rise to the formation of a suitably coloured chromate deposit.
  • the metallic compounds that can be used, there are the silver salts (for example silver nitrate) which lead to the formation of a shiny black chromium plating film, which looks good but of which the resistance to corrosion is affected by metallic pollutions (zinc, iron, etc.).
  • silver salts for example silver nitrate
  • metallic pollutions zinc, iron, etc.
  • a chromium-plating bath which contains besides chromium (6) and sulphate ions, a copper salt and a mixture of acetic acid and formic acid. Unfortunately, when using this kind of bath, the deposit obtained is dull, this making it less interesting at the industrial level.
  • the invention further relates to the baths used in carrying out the said method.
  • molybdic ( ) ions with the copper ions, also produces according to the invention, a shiny black deposit with excellent anti-corrosion properties.
  • the simultaneous use of copper ions and molybdic ions implies that fairly large quantities of these ions are used; the best results are obtained when operating with concentrations of between 15 and 30 g/l of copper ions and between 0.15 and 5 g/l of molybdic ions ( );
  • the conditions of operation, to obtain the chromium-plating according to the invention can be the conditions conventionally used for chromium-plating zinc or cadmium surfaces. These conditions are for example:
  • the pieces to be treated according to the invention have of course a coating of black and shiny chromate which is very adherent and constitutes a good protection against corrosion.
  • a bath was prepared for this purpose containing:
  • the piece to be protected was dipped into this bath, at ambient temperature (20-27°C) with air-stirring of the bath, and for a duration of 2 minutes.
  • the resulting shiny black piece was then rinsed and dipped into a phosphating bath containing 12 g/l of sodium hexametaphosphate, for one minute at 20°C, without stirring.
  • the piece removed from the bath was then dried.
  • a bath was prepared containing:
  • the piece to be treated was dipped in this bath (at 20°C) for about 2 minutes.
  • the resulting piece once removed from the bath and after rinsing, can be given the phosphating treatment to improve the polished finish and resistance to corrosion of the protective coating.

Abstract

An aqueous bath for black chromate plating of a surface of zinc, zinc alloy or cadmium alloy containing sulphate ions, 5 to 40 g/l of hexavalent chromium, 0.25 to 30 g/l of copper ions, 0.1 to 5 g/l of silver ions and/or molybdic ions, 30 to 120 g/l of acetic acid and 0 to 6 g/l of formic acid. Such surfaces plated by the method using the said bath produces a shiny black adherent coating giving good protection against corrosion of the substrate.

Description

  • The present invention relates to new bath permitting, by chromium plating, to obtain a shiny black coating on surfaces of zinc, or zinc-or cadmium-containing alloys.
  • The protection of surfaces of zinc, or of zinc-or cadmium-containing surfaces by chromium-plating said surfaces, has already been described.
  • The solutions used to this effect contain essentially chromium (for example in sodium or potassium dichromate and or chromic acid form), sulphate ions and, in some cases a metallic compound giving rise to the formation of a suitably coloured chromate deposit.
  • Amongst the metallic compounds that can be used, there are the silver salts (for example silver nitrate) which lead to the formation of a shiny black chromium plating film, which looks good but of which the resistance to corrosion is affected by metallic pollutions (zinc, iron, etc.).
  • However, the baths usable for obtaining these silver-containing coatings are rather expensive to prepare and to maintain. For this reason, attempts have been made to find compounds of metals other than silver which, when used in chromium-plating baths, could give black, shiny and corrosion-resistant coatings.
  • A chromium-plating bath has recently been described which contains besides chromium (6) and sulphate ions, a copper salt and a mixture of acetic acid and formic acid. Unfortunately, when using this kind of bath, the deposit obtained is dull, this making it less interesting at the industrial level.
  • It is the object of the present invention to overcome this drawback by proposing a method for chromium-plating surfaces of zinc, or of zinc or cadmium alloys, the said method producing a shiny black coating with good adherence to the support and ensuring a good protection against corrosion of the support, which method consists in placing the support to be chromium - plated in contact with a bath containing:
    • 5 - 40 g/l , expressed in Cr, of hexavalent chromium,
    • sulphate ions,
    • 0.025 - 40 g/l of cupric ions,
    • 0.1 - 5 g/l of ions selected from silver and the molybdic ion,
    • 30 - 120 g/l of acetic acid,
    • and 0 - 6 g/l of formic acid.
  • The invention further relates to the baths used in carrying out the said method.
  • It will be noted:
    • - that the quantities of chromium ions to be used are substantially the same as those currently used in the chromium-plating baths,
      that sulphate ions are used, as known,. the effect of these ions being, all other things being equal, to improve the plating speed and also the adherence of the deposits to the support, especially when said sulphate ions are added in the form of sodium sulphate and sulphuric acid; said sulphate ions can also be added in the form of a copper sulphate for example,
    • - and that cupric ions will be used in any case, these ions producing a chromium-plating of a very pleasant colour,
    • - that the shiny finish of the deposits is obtained due to the presence, with the cupric ions, of another ion selected from silver or the molybdic ion.
  • It is known that the use of silver has already been recommended, but the simultaneous use of copper ions and silver ions has never been described. When simultaneously using these two ions, the operation will take place, according to the invention, in the presence of preferably 0.025 - 0.2 g/l of copper ions and preferably
    0.1 - 0.2 g/l of silver ions. It is inside these ranges of concentration that the best results are obtained.
  • The use of molybdic (
    Figure imgb0001
    ) ions with the copper ions, also produces according to the invention, a shiny black deposit with excellent anti-corrosion properties. The simultaneous use of copper ions and molybdic ions implies that fairly large quantities of these ions are used; the best results are obtained when operating with concentrations of between 15 and 30 g/l of copper ions and between 0.15 and 5 g/l of molybdic ions (
    Figure imgb0002
    );
    • - that in all cases (whether using the copper-silver combination, or the copper-molybdate combination or the copper-silver-molybdate combination) the baths will contain acetic acid; the concentrations of that acid are variable and can be between about 30 and about 120 g/l. Advantageously, they will be between 65 and 90 g/l,
    • - that, finally, in the special case of a copper-molybdate bath, it is advantageous to use, in addition to acetic acid, a certain quantity of formic acid, the preferred concentration of this acid being about 3 g/1.
  • The conditions of operation, to obtain the chromium-plating according to the invention can be the conditions conventionally used for chromium-plating zinc or cadmium surfaces. These conditions are for example:
    • - a pH obviously acid, between 0.5 and 4,
    • - a temperature approaching the ambient temperature, i.e. between about 15 and 40°C,
    • - a period of contact of the piece to be treated and the bath, which can vary, depending on the Deaths, between 10 seconds and 10 minutes,
    • - with or without stirring.
  • The pieces to be treated according to the invention have of course a coating of black and shiny chromate which is very adherent and constitutes a good protection against corrosion.
  • It is however possible to further improve the properties of these coatings, and in particular in certain cases, the shiny finish of the deposit, and its efficiency as a protector against corrosion, by submitting the piece thus coated to a post-rinse with a phosphating bath. The usable phosphating baths are known per se and have already been recommended for certain applications, such as for example for polishing certain deposits. It is considered that in the case of the deposits according to the invention (copper-silver or copper-molybdates) such rinsing baths are specifically efficient and especially advantageous in that they improve the protective effect of the coatings. Amongst the baths usable, the following are given by way of example and non-restrictively:
    • - baths containing up to 5% by weight of phosphoric acid,
    • - baths'containing between 5 and 20 g/l of sodium hexametaphosphate,
    • - baths containing between 0.5 and 15 g/l of monosodium phosphate and between 0.5 and 15 g/l of monopotassium phosphate.
  • As indicated hereinabove, the exact composition of phosphating baths can vary to large extents, but very good results have always been obtained with the special baths indicated hereinabove.
  • The conditions required for this phosphating treatment are usually as follows:
    • - ambient temperature, i.e. between 15 and 40°C,
    • - duration between 10 seconds and 5 minutes, in general about one minute.
    • - with or without stirring.
  • The following examples are given by way of information and non-restrictively.
    • Example 1
  • To protect a steel coated with a layer of zinc.
  • A bath was prepared for this purpose containing:
    Figure imgb0003
  • The piece to be protected was dipped into this bath, at ambient temperature (20-27°C) with air-stirring of the bath, and for a duration of 2 minutes.
  • The resulting shiny black piece was then rinsed and dipped into a phosphating bath containing 12 g/l of sodium hexametaphosphate, for one minute at 20°C, without stirring.
  • The piece removed from the bath was then dried.
    • Example 2
  • A bath was prepared containing:
    Figure imgb0004
  • The piece to be treated was dipped in this bath (at 20°C) for about 2 minutes. The resulting piece, once removed from the bath and after rinsing, can be given the phosphating treatment to improve the polished finish and resistance to corrosion of the protective coating.

Claims (9)

1. An aqueous bath for producing a black chromate plating of a zinc surface or of a surface of a zinc alloy or a cadmium alloy characterized by a content of:
(i) sulphate ions;
(ii) 5 to 40 g/l of hexavalent chromium;
(iii) 0.025 to 30 g/l of copper ions;
(iv) 0.1 to 5 g/1 of silver ions and/or molybdic (
Figure imgb0005
) ions;
(v) 30 to 120 g/1 of acetic acid;
(vi) 0 to 6 g/l of formic acid.
2. An aqueous bath according to Claim 1, wherein the amount of copper ions is 0.025 to 0.2 g/l and the amount of silver ions is 0.1 to 0.2 g/1.
3. An aqueous bath according to Claim 1, wherein the content of copper ions is 15 to 30 g/l and the content of molybdic ions is 0.15 to 5 g/l.
4. An aqueous bath according to Claim 3, containing formic acid in a quantity of about 3 g/l.
5. A method for producing a black chromate plating of a zinc surface or of a surface of a zinc alloy or a cadmium alloy characterized in that an article with a surface of zinc, zinc alloy or cadmium alloy to be chromium plated is dipped in an aqueous bath as defined in any one of Claims 1 to 4 for sufficient time to produce a black chromate layer of the required thickness.
6. A method according to Claim 5, wherein the bath is at a temperature of 15° to 40°C.
7. A method according to Claim 5 or Claim 6 wherein the time of immersion is 10 seconds to 10 minutes.
8. A method according to any one of Claims 5 to 7, wherein the bath is at a pH of between 0.5 and 4.
9. A method according to any one of Claims 5 to 8, wherein the thus plated article is rinsed and then dipped into a phosphating bath.
EP83300852A 1982-02-19 1983-02-18 Bath and method for black chromate plating of zinc and cadmium surfaces Withdrawn EP0087288A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8202816A FR2522023B1 (en) 1982-02-19 1982-02-19 BATHS AND METHODS FOR USING CHROMATE SURFACES OF ZINC AND CADMIUM
FR8202816 1982-02-19

Publications (1)

Publication Number Publication Date
EP0087288A1 true EP0087288A1 (en) 1983-08-31

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EP83300852A Withdrawn EP0087288A1 (en) 1982-02-19 1983-02-18 Bath and method for black chromate plating of zinc and cadmium surfaces

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EP (1) EP0087288A1 (en)
JP (1) JPS58193376A (en)
FR (1) FR2522023B1 (en)
WO (1) WO1983002961A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0264472A1 (en) * 1986-10-21 1988-04-27 Procoat, S.A. Aqueous composition for the passivation of zinc and cadmium surfaces
EP0716163A1 (en) * 1994-12-07 1996-06-12 ATOTECH Deutschland GmbH Chromating bath and process for finishing surfaces of zinc, zinc alloys or cadmium
US6572756B2 (en) 1997-01-31 2003-06-03 Elisha Holding Llc Aqueous electrolytic medium
US6592738B2 (en) 1997-01-31 2003-07-15 Elisha Holding Llc Electrolytic process for treating a conductive surface and products formed thereby
US6599643B2 (en) 1997-01-31 2003-07-29 Elisha Holding Llc Energy enhanced process for treating a conductive surface and products formed thereby
WO2007144336A2 (en) * 2006-06-13 2007-12-21 Wolf-Dieter Franz Cr(vi)-free black chroming

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0730456B2 (en) * 1988-10-05 1995-04-05 日本表面化学株式会社 Treatment liquid for forming black chromate film on zinc / nickel alloy plating
JPH0815584B2 (en) * 1990-11-30 1996-02-21 日本鋼管株式会社 Weldable colored steel sheet
JP2844953B2 (en) * 1991-03-29 1999-01-13 日本鋼管株式会社 Weldable colored steel plate
JP2841912B2 (en) * 1991-03-29 1998-12-24 日本鋼管株式会社 Weldable black steel plate
US5387473A (en) * 1992-03-31 1995-02-07 Nkk Corporation Weldable black steel sheet with low-gloss appearance

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB618667A (en) * 1945-04-14 1949-02-24 Jesse Edwin Stareck Improvements in or relating to the colouring and protection of metals and alloys
US2524577A (en) * 1948-08-10 1950-10-03 United Chromium Inc Dip process for coloring cadmium
US3097978A (en) * 1961-08-17 1963-07-16 Isaac L Newell Method of coating zinc surfaces
DD136979A1 (en) * 1978-06-07 1979-08-08 Alexander Strauch MEANS OF BLACK CHROMATING ZINC

Family Cites Families (4)

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US3127279A (en) * 1964-03-31 Aqueous black coating composition con-
US2302643A (en) * 1941-05-26 1942-11-17 Parker Rust Proof Co Method and composition for treating metals
SU681114A1 (en) * 1973-12-10 1979-08-28 Ордена Трудового Красного Знамени Институт Химии И Химической Технологии Ан Литовской Сср Solution for black passivated zinc
DE2445318C3 (en) * 1974-09-23 1979-10-18 Robert Bosch Gmbh, 7000 Stuttgart Bath for yellow chromating galvanized material

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB618667A (en) * 1945-04-14 1949-02-24 Jesse Edwin Stareck Improvements in or relating to the colouring and protection of metals and alloys
US2524577A (en) * 1948-08-10 1950-10-03 United Chromium Inc Dip process for coloring cadmium
US3097978A (en) * 1961-08-17 1963-07-16 Isaac L Newell Method of coating zinc surfaces
DD136979A1 (en) * 1978-06-07 1979-08-08 Alexander Strauch MEANS OF BLACK CHROMATING ZINC

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 90, no. 18, April, 1979, page 190, no. 140877z, Columbus, Ohio, US; & PL-A-083 483 (INSTYTUT MECHANIKI PRECYZYJNEJ) 30-04-1977 *
PLATING AND SURFACE FINISHING, vol. 68, no. 10, October, 1981, pages 54-56; V.G. ROZOVSKY et al.: "Corrosion resistance of black chromate conversion films on zinc" *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0264472A1 (en) * 1986-10-21 1988-04-27 Procoat, S.A. Aqueous composition for the passivation of zinc and cadmium surfaces
EP0716163A1 (en) * 1994-12-07 1996-06-12 ATOTECH Deutschland GmbH Chromating bath and process for finishing surfaces of zinc, zinc alloys or cadmium
FR2727983A1 (en) * 1994-12-07 1996-06-14 Atotech France CHROMATION BATH AND PROCESS FOR FINISHING ZINC, ZINC ALLOY, OR CADMIUM SURFACES
US5876517A (en) * 1994-12-07 1999-03-02 Atotech Deutschland Gmbh Chromate-plating bath and process for finishing zinc zinc alloy or cadmium surfaces
US6572756B2 (en) 1997-01-31 2003-06-03 Elisha Holding Llc Aqueous electrolytic medium
US6592738B2 (en) 1997-01-31 2003-07-15 Elisha Holding Llc Electrolytic process for treating a conductive surface and products formed thereby
US6599643B2 (en) 1997-01-31 2003-07-29 Elisha Holding Llc Energy enhanced process for treating a conductive surface and products formed thereby
WO2007144336A2 (en) * 2006-06-13 2007-12-21 Wolf-Dieter Franz Cr(vi)-free black chroming
EP1876268A1 (en) 2006-06-13 2008-01-09 Wolf-Dieter Franz Black chromium process free of Cr-VI
WO2007144336A3 (en) * 2006-06-13 2008-02-28 Wolf-Dieter Franz Cr(vi)-free black chroming

Also Published As

Publication number Publication date
FR2522023A1 (en) 1983-08-26
FR2522023B1 (en) 1987-08-21
JPS58193376A (en) 1983-11-11
WO1983002961A1 (en) 1983-09-01

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Effective date: 19850925

RIN1 Information on inventor provided before grant (corrected)

Inventor name: JEANNIER, ELIANE