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
  • C23C18/48—Coating with alloys

Definitions

• aqueous acidic composition useful for forming a copper tin coating on a ferrous metal surface without the application of electric current which comprises copper ions in the range of from about 0.01 to 30% by weight calculated as CuSO -5H O, tin ions within the range of about 0.01 to 30% by weight calculated as SnSO, and a long chain aliphatic amine in the range of about 0.01 to by weight.
• compositions and processes which have heretofore been developed have been generally satisfactory, some difiiculties have been encountered where diiferent 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-tin coating which has been produced.
• these copper-tin 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 a 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-tin coating produced has decreased.
• an object of the present invention to provide an improved coating solution from which bright adherent copper-tin coatings (bronze color) may be obtained on a ferrous metal surface, without the use of electric current.
• -It is a further object of the present invention to provide an improved process for forming a bright, adherent copper-tin coating on a variety of ferrous metal surfaces without the use of an electric current.
• Another object of the present invention is to provide an improved composition and process for forming a bright, adherent copper-tin alloy coating on ferrous metal surfaces, which composition and process will tolerate the build-up of an appreciable quantity of ferrous ion in the coating solution without adversely effecting the quality of the copper-tin coating which is produced.
• a further object of the present invention is to provide an improved process wherein a more uniform gold color is obtained over a wide range of operating temperatures.
• the present invention is directed to an aqueous acidic solution containing copper and tin 1011s and a long chain fatty aliphatic amine.
• the novel bath compositions are aqueous acidic solutions containing copper ions in the range of about 0.01 to 30% by weight calculated as CuSO -5H O which solution desirably has a pH within the range of about 0 to 4, preferably within the range of 0.2 to 2.0.
• the copper ions may be incorporated in the plating solution at any suitable form, such as copper metal and/or various copper salts.
• the bath pH 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% by weight of the solution.
• other copper salts may also be used as the source of copper ions, such as copper metaborate, 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, 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 solution in the present invention also contains at least one long chain aliphatic amine having from 8 to 22 carbon atoms per aliphatic chain, preferably the number of carbon atoms is from about 12 to 20 and even more preferably about 12 to 18 carbon atoms.
• the structure of the aliphatic amine is of the formula:
• R may be hydrogen or lower alkyl; R is a long chain aliphatic group containing 8 to 22 carbon atoms and R may be R or R Examples of R are methyl, ethyl, propyl, butyl, pentyl and hexyl; preferably, the R is methyl.
• R examples of R that may be employed in the present invention are the saturated alkyl groups, such as, octyl, nonyl, decyl, undecyl, dodecyl, lauryl, myristyl, stearyl, and the like, or the ethylenically unsaturated hydrocarbons having 8 to 22 carbon atoms.
• the aliphatic amine may be present in the bath in amounts ranging from about 0.01 to about preferably 0.1 to about 1% and even more preferably about 0.2%.
• Acceptable bronze color coatings are obtained when a copperztin ratio ranges from about 0.60l.5 parts by weight to 1, preferably the ratio of copper to tin is in the range of 0.8 to 1.211 and even more preferably 1.1 parts by weight copper to 1 part of tin.
• the tin may be introduced into the bath in a variety of means such as tin metal itself or as various salts.
• the source of tin ions may be tin benzoate, tin metaborate, tin sulfamate, and the like.
• the aqueous acidic plating baths of the present invention are found to give excellent plating results even where the baths contain appreciable quantities of ferrous iron.
• the plating of the present invention may also contain ferrous ions in amounts up to the saturation point of the ferrous ion in the bath, with amounts of ferrous iron ions within the range of about 5 to 80 grams per liter being typical. Where such typical amounts of ferrous ions are present in the bath and even where the ferrous ion content is greater than the saturation point of the bath, it is still found that excellent quality copper-tin coatings can be produced.
• the ferrous metal s rface to be trea d is first cleaned, using any suitable cleaning techniques.
• 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
• the copper-tin plating bath of the present invention Depending upon the particular configuration of the ferrous surface to be treated, 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 2466 C. 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 as are known to those in the art, such as numerous soap containing compositions may be applied to the copper-tin 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-tin finish on the wire is very bright and uniform and shown good adhesion.
• the solutions of the present invention may also be used to form a copper-tin coating which is useful as a lubricant material for warm forming operations, as well as a decorative copper-tin coating.
• Example I Three 4 1. baths were made up to contain 10 g./l. of SnSO 15 g./1. CuSO -5H O, and 3.3. ml. of 1H SO /l. To one of the baths was added 2 g./l. N,N (dimethyl) lauryl amine, to another 2 g./l. N,N (dimethyl) myristyl amine, and to the third g./l. gelatin. Gelatin was used as a control (see US. 3,346,404). Two grades of cleaned mild steel wire were processed through each bath for one minute at F. Both baths containing the aliphatic amines of this invention ga've desirable bright gold colored coatings on both grades of wire. The gelatin bath had a good coating on only one of the grades of wire.
• Example II A test was conducted tocompare N,N (dimethyl) myristyl amine with gelatin as to their effect on the coating color stability with changes in the Cu-Tin ratio.
• Two 4 1. baths were made up containing 13 mls. of H 80, and 15 g./l. of CuSO -5'H 0.
• To one bath was added g./l. of gelatin and to the other 2 g./l.
• N,N (dimethyl) myristyl amine Stannous sulfate was added to each bath and cleaned mild steel wire was processed in each at SnSO concentrations of l,3,5,7,10, and 15 g./l. The coatings were then checked for color.
• the coatings obtained from the bath containing gelatin got progressively lighter in color up to a SnSO, concentration of 10 g./l. Then the color change flattened out. However, the color of the coatings obtained from the bath containing N,N (dimethyl) myristyl amine has a flatter color response at SnSO concentrations between 5 and 10 g./1. han
• gelatin thus allowing for lower operating concentrations and a more economical bath.
• Example III As a liquor coating bath is used in production, it tends to build-up iron in solution. This is iron that is removed from the work in the coating process and goes into solution as Fe' Usual liquor baths tend to start giving yellow looking coatings when the iron builds-up to about 4 /2%.
• An evaluation of N,N (dimethyl) myristyl amine was carried out in a high iron bath, comparing it with a gelatin control. A 4 liter bath was made-up to contain 13 mls. of H 80 15 g./l. of CuSO -5H O, l g./l. SnSO and 2 g./l. of N,N (dimethyl) myristyl amine.
• a second 4 liter bath was made-up with similar amounts of copper, tin, and sulfate ions and 2 g./l. gelatin.
• the two baths were artificially aged with FeSO 7H O and steel wire was processed through each bath at increments of 1% Fe+ At 4% Fe+ the gelatin bath started to give coatings of a yellower, less uniform color, while the bath containing N,N (dimethyl) myristyl amine showed no changes in coating color, even at 6% Fe.
• a particularly useful composition that may be employed in replenishing the active compounds of the present invention is a concentrate composition containing the following ingredients:
• An aqueous acidic composition of improved color stability useful for forming a copper-tin coating on a ferrous metal surface without the application of electric current which comprises copper ions in the range of from about 0.01 to 30% by weight calculated as CuSO -5H O, tin ions within the range of about 0.01 to 30% by weight calculated as SnSO and a long chain aliphatic amine of the formula:
• R is independently selected from the group consisting of hydrogen and lower alkyl having 1 to 6 carbon atoms; R is a long chain aliphatic group containing from 8 to 22 carbon atoms and R is independently selected from the group consisting of R and R in the range of about 0.01 to 10% by weight.
• composition of claim 1 wherein the ratio of copper to tin ranges from about 0.60 to 1.521 on a parts by weight basis.
• composition of claim 2 wherein the ratio of copper to tin is about 1.1:1.
• a process for forming a copper-tin coating on ferrous metal surface which comprises treating the ferrous metal surface to be coated with a coating composition as claimed in claim 1 and maintaining this composition in contact with the ferrous metal surface for a period sufficient to effect the formation of the coppertin coating.
• a process for forming a copper-tin coating on ferrous metal surface which comprises treating the ferrous metal surface to be coated with a coating composition as claimed in claim 2 and maintaining this composition in contact with the ferrous metal surface for a period sufficient to effect the formation of the copper-tin coatmg.
• a replenishing composition useful for forming an aqueous acidic copper-tin coating composition which coating composition is useful for forming a copper-tin coating on ferrous metal surfaces without the application of electric current comprising copper ions (calculated as CuSOl -SH O) present in an amount ranging from 40 to by weight, tin ions (calculated as SnSO present in an amount ranging from 5 to 30% by weight and a long chain aliphatic amine of the formula:
• R is independently selected from the group consisting of hydrogen and lower alkyl having 1 to 6 carbon atoms; R is a long chain aliphatic group containing from 8 to 22 carbon atoms and R is independently selected from the group consisting of R and R present in an amount ranging from 0.5 to 10% by weight.
• composition of claim 1 containing greater than about 4% by weight Fe+ ions.
• Nr R (R Signed a nd Scaled this T weary-first D 3) of November I978 [SEAL] Arrest:

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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)
• Electroplating And Plating Baths Therefor (AREA)

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  • BE BE793769D patent/BE793769A/xx unknown
• 1972
  • 1972-01-17 US US00218485A patent/US3736157A/en not_active Expired - Lifetime
• 1973
  • 1973-01-08 FR FR7300464A patent/FR2168317B1/fr not_active Expired
  • 1973-01-13 DE DE2301639A patent/DE2301639A1/de active Pending
  • 1973-01-17 ZA ZA730351A patent/ZA73351B/xx unknown
  • 1973-01-17 CA CA161,510A patent/CA989103A/en not_active Expired
  • 1973-03-07 JP JP2626973A patent/JPS5531181B2/ja not_active Expired

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