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
  • C25D15/02—Combined electrolytic and electrophoretic processes with charged materials
• • 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
  • C25D5/627—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
  • Y10S428/9265—Special properties
  • Y10S428/927—Decorative informative
• • 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
  • 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
  • Y10S428/936—Chemical deposition, e.g. electroless plating
• • 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.]
  • Y10T428/1266—O, S, or organic compound in metal 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
  • Y10T428/12806—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
  • Y10T428/12896—Ag-base component

Definitions

• the invention relates to a method for covering objects with a decorative bright nickel/ chromium coating, as well as objects covered by applying this method.
• the nickel layer For, in a micro-crack pattern in the chromium layer the largest possible portion of the underlying nickel layer will be set free, so the corroding current, caused by the galvanic action, is minimal per surface unit.
• This disadvantage of this method is that firstly the precipitation of chromium on chromium is hard to achieve, and secondly it takes longer to cover with chromium plate (in the order of magnitude of 7 to 14 min.), whereas formerly, so before the duplex method was applied, it would take only from 1 to 2 minutes to cover with a chromium coating in a normal chromium bath.
• the inventor has now found that a more delicate open structure of the chromium coating of the bright nickel may be achieved by applying a very thin metal layer between the bright nickel layer and the chromium layer from a galvanic bath containing solid matter in suspended condition.
• the bright nickel layer is thus covered by a thin metal layer in which solid matter, as conductive as or less conductive than graphite, is embedded, so that later on no chromium'layer can precipitate on the nonor ill conducting places, as formed by the solid particles, so an interruption in the chromium layer takes place.
• any type of galvanic bath may be taken for the application of the thin intermediate metal layer.
• an intermediate layer is applied from a galvanic bath, producing a metal layer no less anodic than the ground nickel coating and no more cathodic than the chromium coating.
• the invention relates to a method for covering objects with a decorative bright nickel/chromium coating, characterized in that, after the bright nickel plating and before the chromium plating takes place, an intermediate metal layer is applied electrolytically, keeping a solid, nonor less conductive substance embedded.
• a metal intermediate layer is applied in this case, consisting of nickel, silver or of a metal (including elements and alloys),
• the corrosion proof chromium (II)oxide of the top chromium layer is as cathodic as silver, metals more cathodic than silver are less desirable. Therefore, as mentioned before, metals, such as silver, nickel, and the metals found between these two in the electrochemical series, are preferably applied.
• metals including elements and alloys found in between nickel and silver in the elecerochemical series, and which, can be produced galvanically, antimony, bismuth, monel, etc. may be applied.
• the height of the intermediate metal layer only has to be sufficient to embed the solid matter.
• the particles produced in the solid-matter bath may be made up out of aluminum oxide, silicon carbide, chromous oxide, ceric oxide, diamond powder and any other solid matter which is sufficiently fine and does not dissolve in the bath.
• the particles have to be of as small as size as possible causing the intermediate metal layer to be as thin as possible.
• no particles in an intermediate nickel layer with a height of the layer of 0.1 1.
• no particles can be applied of the order of magnitude of 10/2.
• the size of the particles has to be taken as small as is possible, as particles of a larger size will easily cause a rough precipitation.
• the application of particles of a smaller diameter will increase the resistance to corrosion even more, the more so as a sealing-off effect will be produced by the solid particles on the dangerous pores which will act upon the ground layer of nickel.
• the size of the particles should be kept below 10 and preferably even below 1 1.
• The. solid matter may even have the size of colloidal magnitude, as will be the case for instance in colloidal graphite.
• graphite is a semi-conductor does not present any difficulties.
• the height of the chromium layer to be applied later on should also be adapted to the size of the solid particles, so there will be no risk of the very fine pores closing up when the chromium layer is too thick.
• barium chloride or hydrogen sulfide may be added for example to a solution of nickel sulfate, so a very fine precipitation of barium sulfate or of nickel sulfide will be produced. These two substances are in this case non-soluble in a solution of acid.
• potassium sulfide for example produces a satisfactory addition in the case of a silver bath is applied as a bath to produce the intermediate layer, as in this way the non-soluble silver sulfide will come into being.
• the group of positively charged metal hydroxide $018 which is stable in acid surroundings, and the parts of which are of a colloidal size, are extremely well-suited to be applied in acid baths for an intermediate treatment (iron-hydroxide, indium-hydroxide, aluminium-hydroxide, thorium-hydroxide)
• metal-hydroxides the metal-salts are added in an aqueous solution, to which purpose sulfates and chlorides are specially suited. In this case hydroxide is produced in said bath.
• the particles are kept suspended by blowing in air, or by applying a stirrer. In baths using a humidifier no air can be blown in because of too large a formation of foam.
• Example I An iron object is nickel-plated for 10 min. at a./dm. at 60 C. in the following bath, having a pH of 4, in which the object is moved by cathodic motion:
• the object is nickel-plated, without an intermediate washing, in a bright nickel bath of the same composition, however, by adding 100 g./l. of silica, the particles of which have the size of 0.2a for l min. at 5 a./dm. causing a layer of 1 to come into being.
• the solid matter is kept suspended in this bath by a stirrer.
• this can be done in the ordinary Way, e.g. in a bath, containing 300 g./l. CrO and '3 g./l. H SO by plating for 1 min. at 15-20 a./dm. at 40 C.
• a strongly increased resistance to corrosion will then be observed in respect to an analogous object being covered in a similar bath under similar circumstances by a bright nickel layer and a chromium layer though without an intermediate nickel layer.
• Example 2 An object made of Zamac (an aluminium-coppermagnesium-zinc alloy) covered by a layer of 8a of copper, is nickel plated for 15 min. at 4 a./dm. at 60 C. in the following bright nickel bath, having a pH of 3.5 which is kept in agitation by blowing air into it.
• Zamac an aluminium-coppermagnesium-zinc alloy
• Nickel-sulfate NiSO g./l 270 Nickel-chloride, NiCl g./l Cobaltic-sulfate, Co (SO g./l '3 Boric acid, H BO g./l 40 Formic acid, HCOOH g./l 20 Formalin, 40% HCHO ml./l 3
• Example 3 An object is nickel-plated with a bright nickel layer according to Example 1. After an intermediate washing the object is silver-plated in -a silver bath of the following composition:
• the silver bath also contains 150 g./l. of aluminium oxide with its particles having a size of 0.3
• the silverplating takes place for 20 sec. at 40 C. at 4 a./dm. producing a layer of about 0.8a.
• the object After rinsing the object is chromium-plated for 1 min. at 20 a./dm. in the normal sulfuric acid/ chromium bath.
• Example 4 An object is nickel-plated in a bright nickel bath according to Example 1. Without an intermediate washing the object is then nickel-plated for 0.5 min. at 5 a./dm. in the following bath, producing a layer of 0.5 1..
• Nickel-sulfate NiSO g./l 400 Boric acid, H BO g./l 40 Barium chloride, BaCl g./l 100 Saccharine, C H SO NHCO g./l 2
• barium chloride takes place in an aqueous solution, slowly and by stirring well.
• the organic substances are added after the barium sulfate has formed a precipitation, this in connection with the high absorping thereon a bright nickel plating, applying thereto an intermediate metal layer containing particles, said particles having a conductivity not exceeding the conductivity of graphite and plating chromium over said intermediate layer.
• a method according to claim 5, wherein the thickness of said layer is between about .5 to 1 micron.
• a method of coating an object with a decorative bright nickel/chromium coating comprising plating an object with a bright nickel plating, electrolytically depositing thereon an intermediate metal layer containing particles, said particles having a conductivity not exceeding the conductivity of graphite, said intermediate layer being deposited from a plating bath containing said particles, and plating chromium over said intermediate layer.
• concentration of said particles in said bath is about 100-200 grams per liter.
• a method of .coating an object with a decorative bright nickel/chromium coating comprising plating an object with a bright nickel plating, electrolytically depositing thereon an intermediate metal layer containing particles from a plating bath containing said particles, said particles having a conductivity not exceeding the conductivity of graphite, the size of said particles not exceeding about 1 micron with the thickness of said intermediate layer being between about .5 to about several microns, and plating chromium over said intermediate layer.
• said plating bath is a bright nickel plating bath containing about -200 grams per liter of said particles.
• An object comprising a base having thereon a bright nickel coating, an intermediate metal layer over said coating, said intermediate layer having therein particles having a conductivity not exceeding the conductivity of graphite, and a plated chromium layer over said intermediate layer.

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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)
• Electroplating Methods And Accessories (AREA)
• Electroplating And Plating Baths Therefor (AREA)

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Cited By (12)

Citations (4)

• 0
  • NL NL275167D patent/NL275167A/xx unknown
  • NL NL122246D patent/NL122246C/xx active
• 1963
  • 1963-02-07 GB GB5038/63A patent/GB1039741A/en not_active Expired
  • 1963-02-15 DE DE1496927A patent/DE1496927C3/de not_active Expired
  • 1963-02-21 SE SE1893/63A patent/SE302555B/xx unknown
  • 1963-02-25 US US260854A patent/US3298802A/en not_active Expired - Lifetime

Patent Citations (6)

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