Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/10—Electroplating with more than one layer of the same or of different metals
  • C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
  • C25D5/14—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium two or more layers being of nickel or chromium, e.g. duplex or triplex layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D15/00—Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/04—Electroplating: Baths therefor from solutions of chromium
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/12—Electroplating: Baths therefor from solutions of nickel or cobalt
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/60—Electroplating characterised by the structure or texture of the layers
  • C25D5/623—Porosity of the layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/60—Electroplating characterised by the structure or texture of the layers
  • C25D5/625—Discontinuous layers, e.g. microcracked layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/627—Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/922—Static electricity metal bleed-off metallic stock
  • Y10S428/923—Physical dimension
  • Y10S428/924—Composite
  • Y10S428/926—Thickness of individual layer specified
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/922—Static electricity metal bleed-off metallic stock
  • Y10S428/9335—Product by special process
  • Y10S428/934—Electrical process
  • Y10S428/935—Electroplating
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12479—Porous [e.g., foamed, spongy, cracked, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12639—Adjacent, identical composition, components
  • Y10T428/12646—Group VIII or IB metal-base
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
  • Y10T428/12826—Group VIB metal-base component
  • Y10T428/12847—Cr-base component
  • Y10T428/12854—Next to Co-, Fe-, or Ni-base component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12861—Group VIII or IB metal-base component
  • Y10T428/12944—Ni-base component

Definitions

• any chromium layer is more or less of a porous nature, a crack-free chromium layer Will therefore always show pores to a greater or lesser extent, caused by the chromiums ill-covering property. This is the reason why the micro-crack chromium has been developed. In this case one does not attempt to eliminate the galvanic action, but they are here produced on purpose.
• the micro-crack pattern of the chromium layer causes such a large surface of the nickel to be laid bare, that the current density of the corroding current is practically negligible, so that, for this very reason, a considerable improvement is achieved against the corrosion.
• the micro-crack pattern can be made visible by means of copper-plating. Use is made here of the property that no copper precipitation takes place on chromium, but does so on nickel. After a test by microscope, where it is enlarged at least 200 times, the crack pattern becomes visible. The most delicate meshwork at present produced, will leave small islands between the cracks having a diameter of several microns.
• the inventor has found that a considerable improvement in the corrosion resistance may be obtained if care is taken that the chromium coating on the nickel coating is precipitated in a microporous manner from the very first moment. This may be achieved either by precipitating the top layer of the nickel coating itself in a microporous manner (first case), or by seeing to it that the chromium per se will precipitate in a microporous manner (second case).
• the ill-covering property of the chro- "ice mium is made use of. If proper care is taken that the depth of the openings in the nickel layer is for example 2-3 times as much as the diameter of these openings, the bottom parts of these openings will stay free of chromium, causing a microporous structure.
• colloidal particles as found in an emulsion, according to the invention. and 0.1a.
• Nickel-plating and chromium-plating in an emulsion has been unknown up to now. On the contrary, so far every care was taken to keep a bath free from any organic impurities.
• the method according to the invention may be applied by having this new emulsion-plating take place either in a nickel bath (first case) or in a chromium bath (second case).
• a very short nickel coating is applied after the normal bright nickel in an emulsion bright nickel bath of let us say %2,LL. This will cause a micro-porous layer on top of the bright nickel, with pores having a diameter in the order of magnitude of the colloidal particles with the result that the chromium plating taking place hereafter will have a microporous structure in the order of magnitude of 0.25
• the improvement in the corrosion resistance found by means of the corrodkote test is in the order of magnitude of 15 to 20 times that of a normal chromium coating.
• the strongly oxidizing property has to be taken into account, as well as the high temperature of the chromium bath.
• oils, waxes, resins and emulsifying agents have to be applied which cannot oxidise.
• Specially suited to this purpose appear in this case the not water soluble halogenfluoro carboxylic acid oils and waxes which cannot be oxidised even in a concentrated sulfuric acid.
• emulsifying agents the water soluble fluoro carboxylic acids or the fluoro sulfonic acids which are oxidation resistant as Well, may be applied.
• Example 1 An object is bright nickel plated until its plating has a thickness of 40 in the following nickel bath:
• the average layer thickness of this layer of nickel as strewn with micropores amounts to 0.8 14.
• the object thusbright nickeland chromium-plated is copper-plated electrolytically, so as to be able to determine the microporous structure when magnifying it at least 200 times, one will find a delicately distributed microporous structure, and when taking the corrodkote test, an improvement in the corrosion is found of 14 times in proportion to the normal bright nickel-chromium coating.
• Example 2 An object is 'bright nickel-plated in a normal bright nickel bath until the layer has reached a thickness of 40 Hereafter the object is chromium-plated in the following bath:
• the chromium-plating is done by blowing in with air for 2 min. with a density of current of A./dm. and at a temperature of 40 C. The object will emerge from the chromium bath highly bright.
• the structure After copper-plating it so as to be able to appreciate the micro-porous structure, the structure, on magnifying it 500 times, appears to be finely divided and open.
• the corrodkote-test will show an improvement of 18 with respect to the normal chromium-nickel coating.
• a method of producing a micro-porous chromium plating on an object comprising the steps of electroplating a layer of nickel on said object from a nickel electroplating bath and electroplating a layer of chromium on said nickel layer from a chromium plating bath, one of said plating baths being an emulsion whereby the chromium layer which is produced is micro-porous, the emulsified liquid particles of said emulsion being oxidation resistant under the electroplating conditions.
• a method according to claim 2 wherein the emulsified liquid particles in said emulsion are selected from the class consisting of oils, resins and waxes.
• both of said nickel plating baths are bright nickel plating baths.
• emulsified liquid particles in said emulsion are selected from the class consisting of oxidation-resistant oils, resins and waxes.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Paints Or Removers (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Chemical Treatment Of Metals (AREA)
• Electroplating And Plating Baths Therefor (AREA)
• Electroplating Methods And Accessories (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=19753439

Family Applications (1)

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Cited By (14)

Citations (3)

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• 0
  • NL NL121791D patent/NL121791C/xx active
  • NL NL271860D patent/NL271860A/xx unknown
• 1962
  • 1962-11-01 GB GB41441/62A patent/GB1020285A/en not_active Expired
  • 1962-11-24 DE DEN22400A patent/DE1242969B/de active Pending
  • 1962-11-24 SE SE1264762A patent/SE213547C1/sv unknown
  • 1962-11-26 FR FR916618A patent/FR1345235A/fr not_active Expired
  • 1962-11-27 US US240445A patent/US3282810A/en not_active Expired - Lifetime

Patent Citations (5)

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