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
  • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
  • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
  • C23C18/31—Coating with metals
  • C23C18/38—Coating with copper
• • 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
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal

Definitions

• ABSTRACT A plating solution suitable for the electroless deposition of copper on ferrous metal surfaces which comprises an aqueous acidic solution containing copper ions; chloride, bromide, or iodide ions; 3 polyalkylene glycol; and a tertiary amine compound of the structure:
• a is zero or 1;
• b is 2 or 3;
• a b is 3;
• n is 0 to 4, inclusive; or substituted alkyl R is alkyl/of 1 to 4 carbon atoms where the substituent may be hydroxy or halo; and,
• R is phenyl or substituted phenyl where the substituent may be mono-, di-, or trihalo or alkyl of 1 to 4 carbon atoms.
• This invention relates to a novel composition and process for the treatment of metal surfaces and more particularly it relates to a composition and process for the electroless copper plating of ferrous metal surfaces.
• compositions and processes which I have heretofore been developed have been generally satisfactory, some difficulties have been encountered where different types and grades of ferrous metal surfaces have been treated.
• variations in the type of ferrous metal being treated have resulted in similar variations in the quality of the copper coating which has been produced.
• these cooper coating solutions have been used for treating steel wire, prior to wire drawing operations, it has often been found to be difficult to consistently obtain a bright, adherent coating.
• the compositions of the prior art have had relatively low tolerance for ferrous iron. With these solutions, as the quantity of ferrous iron in the bath has increased, the quality of the copper coating produced has decreased.
• an object of the present invention to provide an improved coating solution from which bright, adherent copper coatings may be obtained on a variety of ferrous metal surfaces, without the use of electric current.
• v r r a A further object of the present invention is to provide an improved process for forming a bright, adherent copper coating on a variety of ferrous metal surfaces without the use of electric current.
• Another object of the present invention is to provide an improved composition and process for forming a bright, adherent copper coating on ferrous metal surfaces, which composition and process will tolerate the build-up of appreciable quantities of ferrous iron in the coating solution without adversely affecting the quality of the copper coating which is produced.
• the present invention includes an aqueous acidic solution containing copper ions; halide ions selected from chloride, bromide and iodide ions; a polyalkylene glycol; and a tertiary amine compound having the formula:
• a is zero or l
• b is 2 or 3;
• a b is 3;
• n is 0 to 4, inclusive; or substituted alkyl R is alkyl/of l to 4 carbon atoms where the substituent may be hydroxy or halo; and
• R is phenyl or substituted phenyl where the substituent may be mono-, di-, or tri-halo or alkyl of l to 4 carbon atoms.
• the novel plating solutions are aqueous acidic 30 solutions containing copper ions, which solutions desirably have a pH within the range of about 0 to 2, and preferably within the range of about 0.2 to 0.4.
• the copper ions are desirably present in the plating solutions in amounts within the range of about 0.1 to 3.0 percent by weight of the solution and preferably in an amount within the range of about 0.3 to 0.8 percent by weight of this solution.
• the copper ions may be incorporated in the plating solutions in any suitable form, such as copper metal, and/or various copper salts.
• the bath pI-I may be maintained within the desired range by the addition of sulfuric acid.
• the aqueous acidic plating baths used contain such sulfate ions, they are typically present in amounts within the range of about 0.1 to 30. percent by weight of the solution.
• copper salts may also be used as the source of copper ions, such as copper chloride, copper bromide, copper acetate, copper citrate, copper benzoate, copper metaborate, copper butyrate, copper formate, copper sulfamates, and the like, and that other acids may be used for the pH adjustment of the bath. It is to be appreciated, however, that in using such other salts or acids, particularly those containing halide ions, care should be taken that the amounts of ,such latter ions introduced do not exceed the maximum amounts which can be present in the solution without detrimental effect.
• the plating solutions of the present invention contain halide ions, selected from chloride, bromide, and iodide ions.
• the chloride ions are preferred; Where chloride ions are used, they are desirably present in amounts within the range of about 0.001 to about percent by weight of the solution and preferably in amounts within the range of about 0.01 to 0.5 percent.
• bromide ions are used, they are desirably present in amounts within the range of about 0.001 to 5 percent weight and preferably in amounts within the range of about 0.02 to 0.5 percent by weight of the solution, while the iodide ions, if ,used, are desirably present in amounts within the range of about 0.001 to 5 percent by weight and preferably in amounts within the range of about 0.01 to 0.2 percent by weight of the solution. These are desirably added as the alkali metal salts.
• the polyalkylene glycol used'in the plating baths of the present invention desirably has a molecular weight in excess of about 600 and preferably has a molecular weight within the range of about 1,000 to 20,000 with a more preferred range of from about 1,500 to about 10,000.
• the amount of the polyalkylene glycol in the treating solutions will vary, depending upon the particular molecular weight of the polyalkylene glycol which,
• the polyalkylene glycol is present in the treating bath in amounts within the range of about 0.001 percent by weight of the solution up to its saturation concentration in the bath, with amounts within the range of about 0.006 to 1.0 percent by weight of the solution being preferred, the higher concentrations typically being used with the lower molecular weight materials, and vice versa.
• various polyalkylene glycols may be used, such as polyethylene glycol, polypropylene glycol, polybutylene glycol, and the like. Of these, the polyethyleneglycols are generally preferred and, hence, particular reference will be made to these materials'hereinafter.
• the plating solutions of the present invention also contain at least one tertiary amine compound of the structural formula that has been indicated above.
• the amine compound used will be present in an amount within the range of 0.001 percent by weight of the solution up to their saturation content in the solution.
• amounts of the amine compound within the range of about 0.002 to 0.1 percent b weight of the solution will be used.
• amine compounds that may be used are as follows: triphenyl amine; tribenzyl amine; triphenethyl amine; N,N,N (4-phenyl butyl) amine; hydroxy methyl dibenzyl amine; 2-hydroxy ethyl dibenzyl amine; 4- chlorobutyl diphenyl amine; 4-iodobutyl diphenyl amine; 3-bromopropyl diphenyl amine; mono-, dior trimethyl substituted triphenyl amine; mono-, di-, or trichloro substituted tribenzyl amine, and the like.
• the aqueous acidic plating baths of the present invention arefound to give excellent plating results even where the baths contain appreciable quantities of ferrous iron.
• the plating baths of the present invention may also contain ferrous iron ions in amounts up to the saturation point of the ferrous iron in the bath, with amounts of ferrous iron ions within the range of about 5 to grams per liter being typical. Where such typical amounts of ferrous iron are present in the bath, and even where the ferrous iron content is greater than the saturation point of the path, it is still found that excellent quality copper coatings can be produced.
• the ferrous metal surface to be treated such as a length of steel wire
• this cleaning may include acid pickling, such as .with muriatic acid, alkaline cleaning, such as with alkali metal hydroxide and/or alkali metal permanganate containing cleaners, and may include a combination of several of these cleaning or pre-treating steps.
• acid pickling such as .with muriatic acid
• alkaline cleaning such as with alkali metal hydroxide and/or alkali metal permanganate containing cleaners
• these cleaning or pre-treating steps Following the 'cleaning or pretreating of the steel surface, it is brought into contact with the copper plating bath of the present invention.
• various contacting techniques may be utilized such as immersion, spraying, flooding, and the like.
• the ferrous surface treated is steel wire
• the wire is immersed in the copper plating bath.
• the copper plating bath of the present invention is desirably maintained at a temperature within the range of about 15 to C. and preferably 24 66C. and under these preferred conditions, immersion times of from about 10 seconds to 10 minutes are typical.
• the ferrous metal surface may then be rinsed with water and dried.
• a suitable lubricant may be applied to the coated wire to facilitate a subsequent drawing operation.
• Various lubricant materials such as numerous soap containing compositions, may be applied to the copper plated wire and this lubricant coating then dried thereon.
• the wire may then be subjected to the desired drawing operation and it is found that following the drawing, the copper finish on the wire is very bright and uniform and shows good adhesion.
• the solutions of the present invention may also be used to form a copper coating which is useful as a lubricant material for warm forming operations, as well as a decorative copper coating.
• EXAMPLE I A two liter solution was made up containing 48 grams of CuSO, 5H O, 6 grams of NaCl, 60 mls of H 80 h grams of polyethylene glycol (molecular weight 4000) and 1 percent F++ added as FeSo 7H O. Cleaned mild steel wire was processed through the bath before and after additions of N, N, N, tribenzylamine were made to the bath. The wire was processed in the bath at 100F. for two minutes. After treatment in the copper solution the wire was rinsed then dried with forced air. The N, N, N, tribenzylamine was added so that the total concentration varied from 10 mg per liter to 2000 mg per liter. Very light colored coatings with excellent adhesion were obtained at N, N, N, tribenzylamine concentrations between and 500 mg per liter. Above and below theseconcentrations the coatings were darker in color.
• EXAMPLE 11 A four liter solution was made up containing 96 g of CuSO, 511 0, 120 mils. of H SO 120 mg. of N, N, N, tribenzylamine, 12 gm. of NaCl, and 1 percent Fe-las FeSO, 7H O.
• Polyethylene glycol (molecular weight 4000) was added to the bath in increments of gm up to a total concentration of 1 gm.
• Cleaned mild steel wire was processed through the bath at each increment of polyethylene glycol. The processing time was 2 minutes at 100F.
• the resulting-coating was examined for color and adhesion. The coatingsobtained at polyethylene glycol concentrations below 3/16 g per liter were brownish orange in color and quite porous. Adhesion was marginal. However at a concentration of g per liter of polyethylene glycol, the resulting coating was very light in color and adhesion was excellent.
• EXAMPLE 111 A four liter aqueous bath containing 24 grams per liter of CuSO, 51-1 0, 30 ml/] H 80 400 g/l FeSO, 187F1 0 (8 percent Fe-H-), 3 g/l NaCl and 0.25 g/l polyethylene glycol (molecular weight 4000) was prepared. To the bath were added varying concentrations of dibenzylethanol amine such as 0, 6 g/l, 0.23 g/l and g/l.
• the wire was given the following coating cycle:
• An aqueous acidic solution suitable for forming a copper plate on ferrous metal surfaces without the application of electric current which comprises copper ions, halide ions, selected from chloride, bromide and iodide ions; a polyalkylene glycol selected from the group consisting of polyethylene, polypropylene and polybutylene glycols having a molecular weight in excess of about 600; and a tertiary amine of the formula:
• a is zero or 1;
• b is 2 or 3;
• a b is 3;
• n 0 to 4, inclusive
• R is alkyl or substituted alkyl of l to 4 carbon atoms where the substituent may be hydroxy or halo;
• R is phenyl or substituted phenyl where the substituent may be mono-, di-, or trihalo or alkyl of 1 to 4 carbon atoms wherein the copper ions are present in an amount of about 0.1 to 3 percent by weight, the halide ions are present in an. amount within the range of about 0.001 to 10 percent by weight, the polyalkylene glycol is present in an amount of at least about 0.001 percent by weight, and the amine material is present in an amount of at least 0.001 percent by weight to saturation.
• composition as claimed in claim 1 wherein the polyalkylene glycol has a molecular weight within the range of about 600 to 20,000.
• composition as claimed in claim 1 wherein the halide ions are chloride ions.
• composition of claim 4 wherein b is 3.
• composition of claim 1 wherein R is hydroxyl alkyl of from 1 to 4 carbon atoms.
• composition of claim 1 wherein the amine is N, N, N-tribenzyl'amine 9.
• composition of'claim 1 wherein the amine is N, N dibenzylhydroxyethyl' amine.
• a process for forming a copper coating on ferrous metal surfaces which comprises treating the ferrous metal surface to be coated with the coating com- 13. The process of claim 10 wherein b is 3.
• R is hydroxy alkyl of from 1 to 4 carbon atoms.

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• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemically Coating (AREA)
• Manufacturing Of Printed Wiring (AREA)
• Electroplating And Plating Baths Therefor (AREA)

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Citations (3)

• 0
  • BE BE793376D patent/BE793376A/fr unknown
• 1972
  • 1972-03-13 US US3793037D patent/US3793037A/en not_active Expired - Lifetime
  • 1972-11-22 FR FR7241497A patent/FR2175729B1/fr not_active Expired
  • 1972-12-29 ES ES72410196A patent/ES410196A1/es not_active Expired
• 1973
  • 1973-02-28 AU AU52697/73A patent/AU467404B2/en not_active Expired
  • 1973-02-28 CA CA164,876A patent/CA989105A/en not_active Expired
  • 1973-03-01 ZA ZA731439A patent/ZA731439B/xx unknown
  • 1973-03-09 GB GB1147673A patent/GB1373895A/en not_active Expired
  • 1973-03-12 JP JP2890973A patent/JPS5518782B2/ja not_active Expired
  • 1973-03-13 AR AR24702373A patent/AR197980A1/es active

Patent Citations (3)

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