US3753882A - Method for converting aluminum and aluminum base,and copper and copper base material surfaces from a hydrophobic to a hydraphilic state - Google Patents

Method for converting aluminum and aluminum base,and copper and copper base material surfaces from a hydrophobic to a hydraphilic state Download PDF

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Publication number
US3753882A
US3753882A US00232608A US3753882DA US3753882A US 3753882 A US3753882 A US 3753882A US 00232608 A US00232608 A US 00232608A US 3753882D A US3753882D A US 3753882DA US 3753882 A US3753882 A US 3753882A
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United States
Prior art keywords
copper
aluminum
bath
square foot
base
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US00232608A
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English (en)
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L Missel
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International Business Machines Corp
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International Business Machines Corp
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F1/00—Electrolytic cleaning, degreasing, pickling or descaling
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
    • C25D11/08—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing inorganic acids

Definitions

  • a method of converting an aluminum or aluminum base article surface from a hydrophobic to a hydrophilic state comprising the steps of making the surface to be converted the anode in a bath comprising an acid-free aqueous borax solution at a temperature between 100 and 200 F., and maintaining an applied anode current at a current density not exceeding 5 amperes/ square foot for a total current application maximum of 300 coulombs/square foot.
  • the hydrophilic surface produced is exceptionally amenable to subsequent coating by various paints such as epoxy base, melamine base, latex, oil base, etc.
  • Copper and copper base surfaces are similarly made hydrophilic in the same bath but with the difference in that the copper surface is made the cathode, the current density is at least 1 ampere/square foot, and minimum total current application of 30 coulombs/square foot is utilized.
  • the bath need not be acid-free.
  • the hydrophilic surface so made is extremely amenable to subsequent electroplating, resulting in improved adhesion.
  • This invention relates to electrochemical methods of preparing a surface for subsequent coating, particularly aluminum and copper surfaces, by use of a heated bath comprising an aqueous borax solution acid-free in the case of aluminum.
  • Aluminum and aluminum base materials, and copper and copper base materials are two of the most widely used materials as bases for plating and painting, and for general coating applications.
  • the surfaces of such materials can generally be prepared in the case of copper for subsequent plating, and in the case of aluminum for subsequent painting, by use of electrochemical methods.
  • aluminum surfaces may be anodized utilizing sulphuric acid or chromic acid treatments, preparatory to subsequent coating by epoxy resin base paints, latex base paints, oil base paints, or polyurethane base paints, for example.
  • copper surfaces are often prepared for subsequent coating by electroplating by use of ammonium persulfate activation, or by copper cyanide electrolytic strikes. While these are roughening treatments, the use of these is to assure good adhesion of subsequent electrodeposits such as those from a Watts nickel bath, sulfamate nickel bath, acid copper bath, etc.
  • the method of this invention comprises the process of utilizing an aqueous borax solution (acid-free for aluminum) maintained at a temperature of substantially -200 F., placing two electrodes in the bath, one of which is the article surface to be converted to a hydrophilic state, and applying a current across the electrodes through the bath.
  • aqueous borax solution acid-free for aluminum
  • the article surfaces must be the anode, and the current density does not exceed 5 amperes/ square foot for a total current application not exceeding 300 coulombs/ square foot.
  • copper is made the cathode, with a current density of at least one ampere/square foot for a minimum current application of at least 30 coulombs/square foot.
  • wetting and complexing agents may also be utilized in this bath.
  • a common analysis of equipment is utilizable in both cleaning methods.
  • an aqueous borax solution is utilized in a tank that is non-corrosive and non-reactive with the borax solution, when the solution is heated in a temperature range of substantially 100- 200 F.
  • the borax solution may vary in concentration from a quarter ounce per gallon to saturation amounts at the temperature involved.
  • the solution is maintained acid-free for aluminum. Acid use does not appear to alfect the copper bath.
  • both for copper and aluminum an additional electrode is necessary utilizing the borax bath as the electrolyte.
  • the electrode should be non-corrosive or non-reactive with the bath at the temperature involved, and may be copper, stainless steel, lead or gold, as examples.
  • both materials, the aluminum or aluminum base materials on the one hand and the copper and copper base materials on the other hand should be precleaned prior to the treatment to be described. This essentially means eliminating grease and dirt from the surfaces of the materials.
  • cleaning methods are known in the art, such as vapor degreasing, acid dipping in nitric acid, inhibited alkaline cleaning, and the use in general of deoxidizers and desmutters. Where a freshly machined surface is utilized, only vapor decreasing may be necessary.
  • general acid dips such as in hydrochloric acid, is sufficient.
  • Other techniques for copper also well known in the art.
  • a pre-cleaned aluminum surface may be placed into a heated bath comprising an acid-free aqueous borax solution, heated to a temperature of between substantially 100-200 F.
  • the aluminum surface is made one of two electrodes in the bath, the other electrode being one of the common materials above.
  • a current is applied across the electrodes through the bath acting as the electrolyte, with the aluminum surface being made the anode, and the current density controlled not to exceed amperes/ square foot at the article surface.
  • the current is maintained for a time not exceeding a total current application of 300 coulombs/square foot.
  • the current is discontinued the article removed from the bath, and rinsed by use of Water, alcohol, etc. and dried by spin drying, forced air drying, or other known methods.
  • surfaces of aluminum or aluminum base materials prepared in this manner are extremely hydrophilic and have excellent adhesion properties for subsequent coating by epoxy resin base, epoxy phenolic, epoxy melamine, melamine, latex base paints, oil base paints, polyurethane base paints, and other commonly known paints.
  • wetting agents and complexing agents may be added.
  • Wetting agents are utilized for promoting uniformity of surface activation by the current and to act as supplementary cleaning agents in the removal of trace amounts of residual contaminations from the surface.
  • the complexing agents are utilized to reduce the processing time and current requirements by their activating activity.
  • this particular treatment causes no loss of surface brightness, as opposed to other anodizing treatments that tend to dull the surface.
  • the preferred operating temperature range is within 140- 170 F., with a particular preferred temperature of 150 F. While one quarter ounce per gallon to saturation amount of borax at the operating temperature is utilizable, for aluminum, one quarter to ten ounces per gallon of borax is a preferred concentration range.
  • a range of 3-6 ounces per gallon of borax is utilized, with a preferred range of l-3 amperes/ square foot, and still more preferably 2.5 amperes/square foot.
  • the total current application should not exceed 300 coulombs/ square foot, with 40-75- coulombs/square foot preferred and 50 coulombs/square foot most preferred.
  • Wetting agents may be utilized, particularly sodium lauryl sulphate, and most particularly sodium lauryl sulphate in a percentage of .l% on a weight/volume basis.
  • a complexing agent may be utilized, particularly tetrasodium salt of ethylene diaminetetraacetic acid (EDTA), or sodium gluconate, Rochelle salts, sodium citrate, or other known complexing agents may be utilized.
  • EDTA ethylene diaminetetraacetic acid
  • sodium gluconate sodium gluconate
  • Rochelle salts sodium citrate
  • other known complexing agents may be utilized.
  • optimum operating conditions have been found in a situation utilizing a borax concentration of 4 ounces per gallon at 2.5 amperes/square foot for 20 seconds at substantially 150 F.
  • COPPER In the case of copper and copper base materials, the same bath is utilized. However, the acid-free requirement is waived. Acid use appears to have little or no effect upon the bath.
  • the diiferences for copper is that the copper is made the cathode, whereas before, aluminum was the anode.
  • copper is utilized as the cathode in the same bath comprising an aqueous borax solution at a temperature between substantially -200 F.
  • the preferred range, as with aluminum, is -170" F., with a still more preferred temperature of operation of F.
  • the bath be acid-free.
  • a preferred concentration of borax is bet-ween one quarter ounce per gallon to saturation at the operating temperature, with a preferred operating range of 3-6 ounces per gallon of borax, and still more preferably 4 ounces per gallon.
  • a minimum of one ampere/ square foot current density at the cathode surface is utilized, with a general range of 5-15 amperes/square foot preferred, with most preferably lO amperes/square foot utilized.
  • a minimum of 30 coulombs/ square foot current application is utilized, with a preferred range being between 150-600 coulombs/ square foot, with 300 coulombs/square foot preferred.
  • wetting agents as utilized in the aluminum bath, and the same complexing agents as utilized with the aluminum baths are utilized here.
  • a preferred bath in general has 4 ounces per gallon borax concentration at 150 F. at 10 amperes/ square foot current density for approximately 30 seconds operating time. Upon removal from the bath, the article is rinsed with water, and immediately electroplated without intermediate drying.
  • the surface is not attacked, and no measurable damage can be noted optically or with tracer (stylus type) instruments.
  • the surface nonetheless is methodically activated and shows excellent adhesion for subsequent plating.
  • Aluminum bronze materials comprising essentially 95% copper plus aluminum, silicon and cobalt, as well as unalloyed copper, and other copper alloys have been particularly used in conjunction with this bath. There is no detectable stock removal or detectable surface damage. Subsequent electrodeposits such as nickel have excellent adhesion. For example, using the preferred conditions above, nickel from a nickel sulfamate bath was successfully plated upon the copper prepared in the above manner.
  • the nickel sulfamate bath utilized a half hour treatment of 40 amperes/square foot at 120 F., as known in the art. Also copper from copper sulfate bath, 40 amperes/square foot, 90 F., /2 hour. Plating adhesion was excellent meeting the requirements of US. Federal specifications (e.g. QQ-P-416), as a standard.
  • aluminum bronze prepared by a three minute treatment in a borax solution at a 4-ounce per gallon concentration, containing .l% sodium lauryl sulphate as the wetting agent, the piece being held at 10 amperes/ square foot cathodic at a temperature of 140 F. was subsequently plated in a nickel sulfamate plating bath at 120 F., with a 20 amperes/ square foot current density for one hour, to put on one mil of nickel, as in the prior example.
  • the plating adhesion again was excellent, as measured by the above Federal standard.
  • plating was achieved after a borax activation at fom minutes at 100 F. at 10 amperes/square foot cathodic.
  • Another example showed successful borox ac-- tivation with one minute at F. and ten amperes/ square foot cathodic.
  • the test adhesion according to the above Federal specifications, was excellent. Unalloyed copper, brasses and other copper alloys are actually easier to) prepare for good adhesion than the aluminum bronze a ove.
  • a method for converting the surface of an aluminum and aluminum base article from a hydrophobic to a hydrophilic base comprising the steps of:
  • a method for converting the surface of a copper and copper base articles from a hydrophobic to a hydrophilic state comprising the steps of:
  • the article surface being the cathode
  • the curdensity being at least one ampere per square foot

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  • Chemical & Material Sciences (AREA)
  • Metallurgy (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Electroplating Methods And Accessories (AREA)
  • Electrochemical Coating By Surface Reaction (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Electrolytic Production Of Metals (AREA)
US00232608A 1972-03-07 1972-03-07 Method for converting aluminum and aluminum base,and copper and copper base material surfaces from a hydrophobic to a hydraphilic state Expired - Lifetime US3753882A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US23260872A 1972-03-07 1972-03-07

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US3753882A true US3753882A (en) 1973-08-21

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Country Status (5)

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US (1) US3753882A (enrdf_load_stackoverflow)
JP (1) JPS5438587B2 (enrdf_load_stackoverflow)
DE (1) DE2310638C2 (enrdf_load_stackoverflow)
FR (1) FR2174846B1 (enrdf_load_stackoverflow)
GB (2) GB1404067A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4225397A (en) * 1978-11-06 1980-09-30 Ford Motor Company New and unique aluminum plating method
US4428987A (en) 1982-04-28 1984-01-31 Shell Oil Company Process for improving copper-epoxy adhesion
CN102825260A (zh) * 2012-06-28 2012-12-19 北京工业大学 一种在铝表面制备超亲水浸润表面的方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4006363C1 (enrdf_load_stackoverflow) * 1990-03-01 1991-01-17 Heidelberger Druckmaschinen Ag, 6900 Heidelberg, De
JP6081690B2 (ja) * 2009-12-22 2017-02-15 花王株式会社 液体の冷却方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1532057A (fr) * 1966-07-21 1968-07-05 Cooperatieve Verkopp En Produc Perfectionnements aux procédés pour la désoxydation du cuivre et des alliages de cuivre
GB1243741A (en) * 1969-01-31 1971-08-25 Peter Neufeld Anodising of aluminium in alkaline borate solutions

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4225397A (en) * 1978-11-06 1980-09-30 Ford Motor Company New and unique aluminum plating method
US4428987A (en) 1982-04-28 1984-01-31 Shell Oil Company Process for improving copper-epoxy adhesion
CN102825260A (zh) * 2012-06-28 2012-12-19 北京工业大学 一种在铝表面制备超亲水浸润表面的方法

Also Published As

Publication number Publication date
GB1404067A (en) 1975-08-28
DE2310638C2 (de) 1982-09-09
DE2310638A1 (de) 1973-09-20
JPS49126A (enrdf_load_stackoverflow) 1974-01-05
FR2174846A1 (enrdf_load_stackoverflow) 1973-10-19
FR2174846B1 (enrdf_load_stackoverflow) 1976-04-09
JPS5438587B2 (enrdf_load_stackoverflow) 1979-11-21
GB1404068A (en) 1975-08-28

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