Classifications

• • 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
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/12—Electroplating: Baths therefor from solutions of nickel or cobalt
  • C25D3/14—Electroplating: Baths therefor from solutions of nickel or cobalt from baths containing acetylenic or heterocyclic compounds
  • C25D3/18—Heterocyclic compounds
• • 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
  • C25D5/08—Electroplating with moving electrolyte e.g. jet electroplating
• • 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
  • C25D5/605—Surface topography of the layers, e.g. rough, dendritic or nodular layers
  • C25D5/611—Smooth 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

Definitions

• This invention relates to a novel process for electroplating. More specifically, it relates to high speed bright nickel plating.
• bright nickel plate may be obtained by plating from various types of baths, typically Watts-nickel baths, or modified Wattsnickel baths, or high-chloride nickel plating baths. Operation in these prior art baths typically may include plating from the nickel-containing solution at current densities which may be 1-10 amperes per square decimeter (hereinafter abbreviated as a.s.d.). Commonly these baths may contain a Wide variety of brightening additives-usually a combination of two or more additives which are necessary to obtain a bright, leveled deposit.
• a secondary brightener may be a material which when added to a nickel plating bath in relatively high concentrations, typically l-30 g./l., produces a plate which is characterized by a refined grain structure and moderate luster, but which is not highly reflective.
• a primary brightener may be a material which, when present in amounts of the general order of magnitude of 5-200 mg./l. and used simultaneously with a secondary brightener will permit attainment of a highly reflective deposit over a wide and useful current density rangeln some systems, a third material, a secondary auxiliary brightener, usually in concentrations of 0.1-4 g./l. may be added to further enhance the luster and, particularly, leveling of the deposits.
• the method of this invention for high speed electroplating a bright nickel deposit comprises electroplating said nickel deposit from a nickel bath containing a brightening and leveling amount of phenylpropiolamide, maintaining the cathode current density during said plating at a level of at least 10 a.s.d., and maintaining a high relative velocity between said nickel bath and said cathode thereby obtaining a highly lustrous, leveled nickel plate over a wide cathode current density range.
• the nickel baths which may be employed in practice of this invention may include Watts-type baths, modified Watts-type baths, high-chloride baths, chloride-free baths, sulfamate-containing baths, etc.
• a typical Watts bath may have the following composition (here as elsewhere g./l. means grams per liter):
• a typical modified Watts bath may have the following composition Amount, Preferred, g /l. g./l.
• soluble nickel anodes may be employed with the Watts or modified Watts baths. With the chloride-free systems, the anodes may be either soluble It is a particular feature of certain aspects of this inor insoluble. If nickel is used as the anode, it is preferably vention that it may be possible to attain a high-speed of electrolytic nickel containing a controlled amount of bright nickel deposit characterized by extraordinary desulfur, typically the SD type of nickel manufactured by gree of leveling, extremely high brilliance, and, particu- International Nickel Co.
• This type of anode permits operalarly, by unexpectedly high ductility (especially in chlotion with minimum amount of polarization and oxygen ride-free systems) by use of baths containing phenylproevolution in chloride-free baths.
• insoluble anodes are piolamide together with a secondary brightener.
• the brightening and leveling amount of terial may usually require replenishment of phenylpropiolamide may be 0.2-0.6 g./l., and typically nickel content of the bath and reestablishment of proper 0.3 to 0.5 g./l.
• the preferred concentration of phenylbath pH by addition of a basic nickel compound e.g. propiolamide may be 0.4 g./l.
• водородн ⁇ е ⁇ ески ⁇ е кактивное как кактри ⁇ ество may be aromatic sulfonates, sulfonamides, brightening and leveling quantities of phenylpropiolamide. lfi id or o bi atio thereof, Typical of th amyp y this Compound, when p y as the brightenmatic sulfonates may be benzene monosulfonate, naphing and leveling agent, y be P entin amounts Of at thalene 1,3,6-trisulfonate, and naphthalene 1,5-disulfonate.
• maintaln t t compound Typical of the aromatic sulfonamides may be para-toluene Present in amount below its Solubility llmlt, Whleh, at sulfonamide and dibenzene sulfonamide. Typical of the yp Operating temperatures of w maybe aromatic sulfimides may be saccharin. When phenylproabout Thus commonly phenylproplolemlde piolamide is used in this embodiment together with a secy b p f in amount of about 1n the ondary brightener, the preferred secondary brighteners noted lllllstfatlve batbsmay include 1-4 g./l.
• the secondary brighteners may be present in their extraordinary leveling characteristics together with concgntration of 1 f r bl 1 w eXtremelY high brilliance by use of baths Contammg the preferred secondary brightener, saccharin, is employed, phenylpropiolamide alone i.e. as the sole brightening and it may b6 present in amount f g 1 leveling additive.
• the brightening and A typical bath which may be used in practice of this leveling amount of Phenylpropiolamide may be at least embodiment of the. invention may have the following comabout 0.8 g./l. up to saturation. Saturation typically may position: be 0.9-1.0 g./l. depending upon the temperature, which may be within the range 60 C.-80 C.
• the nickel Amount Preferred plating bath may be self-regulating as to maintenance of Component g-ll. g./l.
• the additive concentration level i.e. the phenylproplol- Nickel 5111MB 250 500 375 amide
• the additive concentration level i.e. the phenylproplol- Nickel 5111MB 250 500 375 amide
• the sole additive when present as the sole additive, may be present Nlckelelilorlden- 75-150 110 h th olid Borlc aold 20-60 45 in amount in excess of its solubility in w 1c case e s phenylpmpwlaml 0 0 4 phase may dissolve as the compound is consumed from saccharin (Na salt)- 1-4 3 solution as by cathode effects including reductive action.
• the solid may not be maintained in the solution proper, but may be maintained in a cartridge or filter
• Another yp bath fvllleh may be used In pfaetleeot through which the plating solution may pass e.g. as it i this embodiment of the invention may have the following pumped to and from the plating bath.
• a typical bath or solution may have the following com osition:
• composition Another typical bath or solution may have the follow- 6 he typic l bath which may be used in practice of ing composition: this embodiment of the invention may have the following composition:
• Another typical bath may have the following composition:
• a metal cathode which has been precleaned and which may have been copper plated may be placed within a nickel plating bath together with either a soluble anode or an insoluble anode as hereinbefore described.
• Typical preferred temperature of the bath during plating may be 60 C.-80 C.
• the baths are preferably maintained at a pH of 2-5, preferably 3.5-4.5, say 4. It is a concomitant advantage of the additive systems of this invention that the baths are operative over a very wide pH range in contrast to prior art brightener systems where much more limited pH ranges are necessary. This insensitivity to pH is of particular importance where insoluble anodes are used, necessitating pH adjustment with a basic nickel compound. Since these basic nickel compounds are most highly reactive below pH 3.5 it is highly advantageous to be able to operate substantially below pH 3.5. It is not necessary to use wetting or anti-pitting agents when plating according to this invention thereby minimizing problems which might arise therefrom because of e.g. foaming, decomposition products of wetting agents, etc.
• the cathode current density will preferably be maintained at a level of at least about a.s.d.
• the high-speed bright nickel plating process of this invention may be effected at a current density of 20-120, preferably 20-60 a.s.d.
• Plating carried out in accordance with this novel technique may permit deposition of predetermined thicknesses of bright, leveled nickel in a time which is as little as 10% or less of the time required when using standard processes presently available.
• production of a bright nickel plate 1 mil thick by the process of this invention may require 3 minutes in contrast to 30 minutes for prior art plating processes.
• the rate of plating may typically be 1-3 minutes per mil of bright nickel plate.
• the novel technique of this invention includes the step of maintaining a high relative velocity between the nickel bath and the cathode. It may be possible to maintain this high relative velocity which serves to replenish the cathode film with nickel ions as they are plated out therefrom, by use of a bath which contains agitation means sufiicient to maintain a substantially homogeneous catholyte. Typically this may be accomplished by use of high speed mixers in the solution.
• the high relative velocity between the nickel bath and the cathode is preferred to maintain the high relative velocity between the nickel bath and the cathode at a level equivalent to about 60-320, say 150 cm./second.
• These velocities may be produced e.g. by varied techniques such as vibration (including ultrasonic) or rotation of the cathode relativeto the solution, by pumping the electrolyte etg. catholyte through the system and over the cathode surface, by very vigorous agitation of the electrolyte by appropriately positioned propellers or other devices, etc.
• the high relative velocity may be maintained by impinging the nickel bath against the cathode. This may be effected by impinging a stream of electrolyte uniformly against those portions of the cathode which are to be plated. In the preferred embodiment, this may be effected by directing a stream of electrolyte, as from a conduit, onto the noted portions of the cathode. If desired, a plurality of streams may be directed onto the cathode surface. Preferably in one embodiment the stream of electrolyte from the conduit may be directed against the cathode in manner to sweep the cathode surface and thereby provide fresh catholyte over the area to be plated. Preferably the impinging stream may contact the cathode at a high rate.
• the nickel plate obtained by the process of this invention may be characterized by its high brightness.
• the deposit is highly reflective over a wide current density range, and free of striations and/or hazy areas, and/or other imperfections.
• the luster obtained is at least comparable in every way to that obtained under normal low speed plating conditions even With the best available bright nickel additive systems.
• the plate obtained by the process of this invention may be further characterized by its high leveling.
• a one mil deposit, plated at e.g. 4060 a.s.d. will substantially obliterate scratches produced by one single pass of zero-grit emery paper when plating is eifected under high speed conditions during a period of two minutes.
• the best plate attainable will merely give either only partial or no obliteration of the scratch lines when the plate is deposited for the same period of time.
• the plate When phenylpropiolamide is used in combination with a secondary brightener, typically saccharin, the plate may possess an unexpectedly high ductility. This high ductility is particularly attainable when the plate is deposited from chloride-free systems. The high ductility can be produced over a reasonably wide range of concentration of phenylpropiolamide. Prior art brightener combinations permit attainment of ductile plate only under relatively narrow and difiicultly controllable concentration limits of primary brighteners.
• the additives used may be readily determined and controlled by spectrophometric analyses in the ultraviolet region.
• the additives may be particularly characterized by high degree of stability under conditions of operation; any decomposition products formed do not undesirably affect the plating characteristics of the system.
• bright high-speed nickel may be plated from a bath having the following composition:
• the solution was passed through a conduit obliquely ontoone end of the surface of a vertically positioned brass electrode with the section to be plated 13.5 cm. long and 1.9 cm. wide, to give an exposed cathode area of 25.7 cm.
• On the front of this highly polished brass cathode there was inscribed a longitudinal 1 cm. wide single pass of zero-grit emery scratches centrally positioned on the cathode surface.
• the back of the cathode was sealed by means of a plastic backing.
• the velocity of the impinging stream was about cm./ second.
• the angle of the downwardly flowing stream was 45 to the vertical.
• the outer periphery of the cathode was bounded by plastic barriers or shields extending outwardly from the cathode thereby etfecting channelling of the electrolyte as it passed over the cathode. This entire assembly was submerged in a body of electrolyte. Cathode contact was made to that section of the strip, not to be plated, which extended out of the solution. A slab of SD nickel was positioned parallel to the cathode at a distance of 20 cm. The times of plating used were 3 minutes (except for Example 4 where the time was 2 minutes) to give a deposit thickness of one mil. In the examples, the additive was varied.
• Example 5 the pH in Examples 1-9 It will be apparent that the novel nickel baths of this was 4 except for Example 5 where the pH was 5.
• the cur-' invention which may contain as additive a composition rent density in these examples was 40 a.s.d. except for selected from the group consisting of (a) at least 0.8 Example 4where it was 60 a.s.d. g./l. of phenylpropiolamide and (b) a secondary bright- Example Amount,
• the bath had the following ener together with 0.2-0.6 g./l. of phenylpropiolamide,
• composition permit attainment of a high speed bright nickel plate.
• component Amount It will be apparent that this invention has been de- Nickfil Sulfate 375. scribed with respect to specific examples and various Boric acid 45' mcidgigftllons Will be apparent to those skilled 1n the art. As not d.
• Addmve e 1. The method of high speed electroplating a bright Temperature 65 C. nickel deposit Which comprises electroplating said nickel pH As noted. deposit from a nickel bath containing soluble nickel salts Current density a.s.d. and a primary brightener consisting essentially of a bright- Example I Amount, Number Additive g./l. pH Comments 10 llif iii i' ::::I:3:13:13 1: i ⁇ 4 3 3 35 highly leveled, ductile g: 4 Do. 3: 4 Do.
• the bath had the following ening and leveling quantity of phenylpropiolamide as composition: the sole brightening and leveling additive present in brightening and leveling amount of at least 0.8 g./ 1., mainfi i i lfamate gg g taining the cathode current density during said plating j f IIIIIIII: at a level of at least 10 a.s.dand maintaininga high A d difive As noted. relative velocity between sald nickel bath and said cathode, thereby obtaining a highly lustrous leveled nickel Temperature C. plate over a wide cathode current density range. pH As noted. 2.

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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 And Plating Baths Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=23097402

Family Applications (1)

Country Status (5)

Cited By (3)

• 1963
  • 1963-06-07 US US286170A patent/US3576725A/en not_active Expired - Lifetime
• 1964
  • 1964-05-22 GB GB21341/64A patent/GB1071884A/en not_active Expired
  • 1964-06-03 DE DE1496898A patent/DE1496898C3/de not_active Expired
  • 1964-06-05 NL NL646406402A patent/NL148656B/xx unknown
  • 1964-06-05 CH CH734164A patent/CH447756A/de unknown

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