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
  • 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
  • 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
  • Y10T428/12903—Cu-base component

Definitions

• This invention relates to improvements in the plated sequence of the type of chromium-nickel-chromium plate described in US. Patent 2,871,550, issued February 3, 1959, which gives extraordinary outdoor corrosion protection to commercial metals susceptible to atmospheric corrosion including ferrous metals, zinc die-cast, aluminum, brasses and'magnesium.
• the improvements which have been found consist in the use of cobalt with the nickel plate which is sandwiched between the two chromium plates.
• the cobalt not only adds greatly to the ductility of bright nickel plate used between the two chromium plates, but also increases to a certain and favorable extent the degree of lateral corrosion of the plate between the two chromium plates which is very desirable instead of corrosion penetration downward into the basis metals.
• Example IV a bright cobalt-nickel alloy plate, Example IV, either on top of a nickel strike or a cobalt strike or a nickel-cobalt strike between the two chromium plates makes possible a much more ductile laminate than is obtained when the bright nickel plate has no cobalt present.
• Patented Aug. 7., 1962 "ice bright nickel plate a minimum of about 10% cobalt to a maaimum of about 50% cobalt should be present in the bright nickel plate.
• the composition of such very ductile bright nickel-cobalt plating baths are shown in Example IV, which gives bright ductile plate even after chromium plating.
• the percentage of cobalt in this bright plate is about 40%, and this is within the preferred percentage of about 10% to 50% cobalt.
• cobalt or cobalt-nickel strike plates on the underneath chromium plate of up to about 0.1 mil thickness followed by at least 0.1 mil thick to 2 mils thick nickel plate, or by the use of the cobalt strike, or the cobalt-nickel strike or the nickel strike, Example III, of up to 0.1 mil thickness followed by at least 0.1 mil to about 2 mils thickness of a bright cobalt-nickel plate containing at least 50% nickel, it is possible to obtain improved ductility for the laminate plate as well as improved corrosion protection especially in recessed articles where the underlying chromium plate may be as low as 0.01 mil chromium.
• the zinc castings be given a copper o-r brass plate before the first or lower chromium plate, the underneath chromium, is applied.
• the lower chromium plate is preferred to be deposited from the crack-free type of high temperature, F. to about F. baths, high ratio type of baths that tend to give a cloudy crack-free plate.
• the steel In plating steel, it is preferred to plate the steel first with chromium or if the steel needs to be preliminarily polished because, for example, of an orange-peel surface caused by drawing or forming operations as with automobile steel bumpers or bumper guards, then it is preferred to zinc plate the steel instead of polishing it, then bufling the Zinc to a high luster and then copper plating the zinc before the first chromium is applied.
• the zinc layer preferably has a thickness of about 0.1 to 2 mils thick before the copper is applied.
• the copper layer is preferably about 0.1 to about 2 mils thick before the first chromium is applied.
• the use of copper or copper alloys or nickel underneath the lower chromium is mainly for the purpose of covering over basis metal defects such as oxide and other insulating inclusions, or to obtain increased ductility for the total plate, and therefore very ductile copper or nickel is preferably used underneath the lower chromium plate.
• first chromium plate the steel directly with the crack-free type of chromium plate.
• the lower chromium plate should have a thickness of at least 0.01 mil and preferably at least about 0.03 mil to a maximum of 0.2 mil.
• the total thickness of the cobalt containing nickel including the cobalt or cobaltnickel strike which is directly on the underlying chromium followed by nickel or nickel-cobalt alloy, or of a nickel strike directly on the chromium plate followed by a nickel-cobalt plate, should be not less than about 0.2 mil or greater than 2 mils.
• the final chromium should have a thickness in the range of about 0.005 to about 0.1 mil, and preferably 0.03 to 0.06 mil.
• nickel plate, cobalt plate or nickel-cobalt plates when nickel plate, cobalt plate or nickel-cobalt plates are referred to, the presence of small percentages of iron or zinc in the bath nevertheless produces plate which is still essentially a nickelcobalt plate.
• impurities may enter the baths, for example, the low pH nickel strikes or cobalt strikes or cobalt-nickel strikes used to plate on top of the lower chromium plate by ferrous articles falling off the plating racks and dissolving in the bath, and thus iron from this source as well as anodes and salts may plate out with the nickel, or cobalt, or cobalt-nickel alloy plate, and yet the 3 resulting plate is, for the purposes of this invention a nickel, cobalt or nickel-cobalt alloy plate.
• the iron content of all of the strike plates may be as high as to iron and still excellent results are obtained.
• the best results are obtained with a nickel strike or a cobalt-nickel strike on top of the underneath chromium layer followed by a bright nickel-cobalt plate containing about 40% cobalt, or the use of a ductile semibright nickel plate against the nickel strike or cobaltnickel strike followed by the bright nickel-cobalt alloy plate containing about 40% cobalt, the soft semi-bright nickel, preferably sulfur-free, constituting at least of the plate between the two chromium plates and the thicknesses of each layer being within the above given ranges.
• the plated articles are thoroughly rinsed, ultra-sonic vibration can be used to aid rinsing especially of blind holes which may entrap chromic acid or chromic salts, then dipped or soaked in 'a reducing solution to reduce hexavalent chromium to the less harmful trivalent chromium. Hydrogen peroxide solutions, sulfite solutions, dextrose, gluconic acid, tartaric acid or Warm oxalic acid solutions are satisfactory for the aqueous reducing solutions.
• the chromium plated articles are again rinsed thoroughly, then given a low pH nickel or nickel-cobalt or cobalt strike.
• low pH nickel and cobalt-nickel and cobalt strike baths can tolerate appreciable concentrations of chromic acid, at least 1 gram/liter and trivalent chromium, at least 3 grams per liter, without the resulting plate having poor adhesion.
• Hydrogen peroxide is a preferred reducing agent to use in the low pH strike baths to reduce chromic acid to trivalent chromium. Only sufficient peroxide should be used to just reduce the chromic acid since excess peroxide is undesirable. If suliite is used in the nickel strike to reduce chromic acid, no excess should be used as the sulfite ion is harmful in these low pH strike baths to both the covering power and in the quality of the plate. Oxalic acid may be used,"
• suitable nickel strike, cobalt strike, nickelcobalt alloy strike and nickel-cobalt alloy baths for use in forming the improved composite electroplates of this invention are given in the examples which follow, but it is to be understood that the baths and conditions given therein are illustrative only.
• Example I Polished steel suitable for use as automobile hub caps is cleaned in a conventional manner and after a final alkaline anodic cleaner is rinsed, acid dipped or anodically etched, and then given a chromium plate of 0.03-0.06 mil thickness from the following hexavalent chromium bath:
• the hub caps are thoroughly rinsed, and given an agitated soak dip in a 5% solution of sodium sulfite, rinsed thoroughly in water and transferred to a low pH cobalt strike bath such as the following:
• This bath is purified electrolytically at a low current I density of, e.g., 2-10 amps. sq. ft. to eliminate zinc, copper and other harmful impurities, and is preferably also continuously or frequently treated with activated carbon.
• the cobalt salts may be fluoborate instead of chloride or sulfate or mixtures may be used.
• the hub caps are then transferred to a ductile semi-bright type Watts nickel plating bath containing an addition agent selected from the class consisting, for example, bromal, chloral hydrate and coumarin, and plated with about 0.8 mil to about 1 mil of semi bright nickel, then transferred to a bright nickel plating bath containing a brightener selected from the class consisting of benzene sulfonamides and sulfonimides, preferably o-benzoyl sulfimide, together with an aliphatic unsaturated compound or compounds, and plated with about 0.2 to about 0.3 mil of bright nickel, then rinsed and transferred to a chromium bath of approximately the following compositions:
• Example II Polished steel hub caps are put through the same steps given in Example I except that the cobalt strike bath was substituted for by the following nickel cobalt strike bath:
• Example 111 Polished steel hub caps are put through the same steps given in Example I except that the cobalt strike bath was substituted for by the following nickel strike bath:
• the bath is purified as described in Example I.
• the nickel salts may be fiuoborate instead of sulfate or chloride, or mixturm may be used.
• HO 3SCH2CE at 3-10 grams/liter. Air agitation preferred. Temperature at 130-l50 F., pH of 3.8-4.5.
• Example IV Polished steel hub caps were put through the same steps given in Example III except that the nickel strike bath was substituted for by the nickel cobalt strike bath set forth above in Example II, and the conditions of forming the nickel cobalt strike in Example II were duplicated.
• Example V Polished steel hub caps were given the initial chromium coating described in Example I, and the chromium was overlaid with a nickel cobalt strike layer by employing the nickel cobalt strike bath and conditions set forth for After removal of the hub caps from the nickel cobalt strike bath they were coated with a semi-bright nickel layer by using the bath described in Example I to produce a thickness of 0.5-1.2 mils. This semi-bright nickel layer was then overlaid with a nickel cobalt alloy plate having a thickness between 0.2 and 0.8 mil, by using the nickel cobalt bath set forth in Example III.
• Example Vl Aluminum bumpers were cleaned and then anodized in a phosphoric acid solution and then given a low pH nickel strike, and then plated in a soft semi-bright nickel to a thickness of about 1 mil and then plated with the sequence in accordance with the procedure in Examples 2 and 4.
• a laminated corrosion protective final coating on a metal base susceptible to atmospheric corrosion comprising a first layer of chromium having a thickness in the range of about 0.01 to about 0.2 mil chromium, an adherent strike plate overlaying said chromium layer of a metal selected from the class consisting of cobalt, nickel and alloys thereof and having a thickness less than about 0.1 mil, said strike plate overlaid by plated metal selected from the class consisting of nickel and cobalt and alloys thereof containing at least 50% nickel, said plated metal being at least partially said nickel cobalt alloy when said strike plate is nickel, the sum of the thicknesses of said strike plate and said plated metal being in the range of about 0.2 mil to 2 mils, and a second chromium plate overlaying said plated metal and adherent thereto in a thickness of about 0.01 to about 0.1 mil.
• a laminated coating in accordance with claim 1 wherein the said plated metal between the two said chromium plates comprises a semi-bright nickel portion overlaid by a bright nickel-cobalt alloy containing from about 10% to 50% cobalt.
• a laminated corrosion protective coating on a combital basis metal susceptible to atmospheric corrosion comprising a base layer of a semi-bright nickel plate having a thickness of 0.2 mil to 2.0 mils, said base layer being overlaid by a first layer of chromium having a thickness in the range of about 0.01 :to about 0.2 mil chromium, an adherent strike plate overlaying said chromium layer of a metal selected from the class consisting of cobalt, nickel and alloys thereof and having a thickness less than about 0.1 mil, said strike plate overlaid by plated metal selected from the class consisting of nickel and cobalt and alloys thereof containing at least 50% nickel, said plated metal being at least partially said nickel cobalt alloy when said strike plate is nickel, the sum of the thicknesses of said strike plate and said plated metal being in the range of about 0.2 mil to 2 mils, and a second chromium plate overlaying said plated metal and adherent thereto in a thickness of about 0.01 to about 0.1 mil.
• a laminated corrosion protective coating on a commercial basis metal susceptible to atmospheric corrosion comprising a base layer selected from the class consisting of zinc and copper and alloys thereof having a thickness in the range of 0.1 to 2 mils, said base layer being overlaid by a first layer of chromium having a thickness in the range of about 0.01 to about 0.2 mil chromium, an adherent strike plate overlaying said chromium layer of a metal selected from the class consisting of cobalt, nickel and alloys thereof and having a thickness less than about 0.1 mil, said strike plate overlaid by plated metal selected from the class consisting of nickel and cobalt and alloys thereof containing at least 50% nickel, said plated metal being at least partially said nickel cobalt alloy When said strike plate is nickel, the sum of the thicknesses of said strike plate and said plated metal being in the range of about 0.2 mil to 2 mils, and a second chromium plate overlaying said plated metal and adherent thereto in a thickness of about 0.01 to about 0.1 mil.
• a laminated corrosion protective coating on a commercial basis metal susceptible to atmospheric corrosion comprising an adherent zinc plate having a thickness in the range of about 0.01-1 mil on said basis metal surface, a copper plate overlaying said zinc plate and adherent thereto, having a thickness in the range of about 0.1 to about 0.5 mil, said copper plate being overlaid with a first layer of chromium having a thickness in the range of about 0.01 to about 0.2 mil chromium, an adherent strike plate overlaying said chromium layer of a metal selected from the class consisting of cobalt, nickel and alloys thereof and having a thickness less than about 0.1 mil, said strike plate overlaid by plated metal selected from the class consisting of nickel and cobalt and alloys thereof containing at least 50% nickel, said plated metal being at least partially said nickel cobalt alloy when said strike plate is nickel, the sum of the thicknesses of said strike plate and said plated metal being in the range of about 0.2 mil to 2 mils, and a second chromium plate overlay

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• Organic Chemistry (AREA)
• Electroplating Methods And Accessories (AREA)

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• 0
  • NL NL248698D patent/NL248698A/xx unknown
  • NL NL127179D patent/NL127179C/xx active
• 1958
  • 1958-11-26 GB GB38138/58A patent/GB855695A/en not_active Expired
• 1959
  • 1959-01-09 FR FR783696A patent/FR1224859A/fr not_active Expired
  • 1959-01-09 DE DEU5892A patent/DE1163115B/de active Pending
  • 1959-02-24 US US794794A patent/US3047939A/en not_active Expired - Lifetime
• 1960
  • 1960-02-23 DE DEU6927A patent/DE1273953B/de active Pending
  • 1960-02-24 FR FR819455A patent/FR77229E/fr not_active Expired
  • 1960-02-24 GB GB6528/60A patent/GB891564A/en not_active Expired

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