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WO1979000608A1 - Electro-traitement d'une surface metallique - Google Patents

Electro-traitement d'une surface metallique Download PDF

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Publication number
WO1979000608A1
WO1979000608A1 PCT/GB1979/000027 GB7900027W WO7900608A1 WO 1979000608 A1 WO1979000608 A1 WO 1979000608A1 GB 7900027 W GB7900027 W GB 7900027W WO 7900608 A1 WO7900608 A1 WO 7900608A1
Authority
WO
WIPO (PCT)
Prior art keywords
metal
solution
alloy
carboxylic acid
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB1979/000027
Other languages
English (en)
Inventor
K Lodge
F Still
J Dennis
D Jones
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
KEMWELL Ltd
Original Assignee
KEMWELL Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by KEMWELL Ltd filed Critical KEMWELL Ltd
Publication of WO1979000608A1 publication Critical patent/WO1979000608A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C25D3/562—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of iron or 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
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/04—Electroplating with moving electrodes
    • C25D5/06—Brush or pad plating

Definitions

  • the invention relates to apparatus and chemicals useful in electrotreating a metal surface by a so-called brush technique.
  • This technique may be used to electroplate or electro-clean a metal surface.
  • the metal surface may be the die surface of a forging or pressing tool , a printed circuit , a printing roller, an aircraft component or the like.
  • the deposit may be put on to increase resistance to wear or to corrosion or both. For convenience and brevity this system will be called collectively "brush plating" .
  • Another method involves applying a plating solution to the metal body by means of a brush anode with the metal body acting as the cathode to deposit a coating from the solution on to the metal body.
  • the brush comprises an electrode having a stylus portion covered by an absorbent material such as soft cotton wool and in use the stylus is moved aver the surface to be plated.
  • This technique became industrial in the 1950's, see e.g. M. Rubinstein, "Brush plating now practical" Materials & Methods (1954) 40 6-8.
  • Brush plating started as a means of repairing defective areas of a vat plated metal surface and it has been adopted commercially for plating in situ large components of ships and air-crafts and fixed items such as statues and roofs.
  • the absorbent cotton wool functions quite well as an absorbent material, it can cause electrical problems and the cotton wool fibres can be released to be included in the plated deposit.
  • the solutions used in brush electroplating are subjected to much more severe operating conditions than those of bath electroplating techniques.
  • the brush electroplating solutions are subjected to high and variable current densities, which can give rise to localised boiling of the solution, and they may also be subjected to large variations, in pH due to localised loss of metal ions from the solution.
  • conventional bath electroplating solutions have been tried for use in brush electroplating, they are generally unsuitable due to their inability to form coating having a sufficient thickness and where relevant a suitable content of alloy.
  • a brush electrode for use in contacting the surface of a metal part to be treated such as the surface of a metal forming tool with a treating solution, comprising an electrode having a stylus portion adapted to hold treating solution, in which the stylus portion includes an absorbent abrasive material.
  • the absorbent abrasive material is formed of synthetic fibres. With such fibres the material can have a large internal volume which gives the material the ability to absorb a large quantity of the treating solution. Synthetic fibres tend to be inert to the acids and heat of the treating solution. Fibres which are angular in shape are much preferred since they tend to be more abrasive. The fibres may be held together in any convenient way; it is preferred to consolidate them by needle punching and binding them by resin.
  • a preferred absorbent abrasive material is a mixed polypropylene/nylon felt bonded with acrylic resin.
  • the material has a fibre density of between 400 g/sq.m. and 1000 g/sq.m. to allow a satisfactory amount of the solution to be absorbed.
  • the thickness of the fibrous material covering the electrode is preferably between 0.2 mm and 15 mm.
  • the absorbent abrasive material may also be used with other suitable materials.
  • the felt may be located on top of a cotton gauze located about the electrode.
  • the absorbent abrasive material may be held to the electrode by any convenient means such as bands or straps. It is usual to hold the material on to the stylus end of the electrode which however may be shaped, e.g. recessed, to receive the material.
  • the electrode used in brush plating is typically inert.
  • the electrode may be formed of inert material such as platinum or platinum alloys, stainless steel or carbon, high purity high density carbon is preferred.
  • the brush electrode of the invention may be used to apply as a treating solution an ⁇ lectr ⁇ cleaning solution or an electroplating solution.
  • the electrode will be cathodic and the treating solution will typically include dilute mineral acids and in the latter case the electrode will be anodic.
  • a method ⁇ f brush electroplating a metal surface comprising connecting the metal surface to the negative pole of a direct current or rectified alternating current power source, wetting a brush electrode of the invention with an aqueous acidic solution containing metal ions which will form a deposit of a metal or an alloy, connecting the brush electrode to the positive pole of the power source, and applying the wetted electrode to the surface of the metal body to make an electrical circuit and deposit the alloy on to the metal body.
  • the metal ions present in the solution rray be adapted to deposit a metal or an alloy on the metal surface being plated. It is preferred for wear-resistance that the ions form a deposit of a binary or a ternary alloy.
  • binary alloys which have been deposited by the method of the invention include cobalt-molybdenum which has been deposited with a molybdenum content of about 8% or more and cobalt-tungsten which has been deposited with a tungsten content of up to about 19%, both alloys being deposited in a coating thickness of up to about 30 um.
  • Examples of other binary alloys which may be deposite by the method are nickel-molybdenum, nickel-tungsten, iron-molybdenum and iron-tungsten, and examples of ternary alloys are iron-nickel-molybdenum and cobalt-tungsten-molybdenum.
  • the metal ions are usually presented as water-soluble salts, and the concentration depends on the particular salt used .
  • cobalt sulphate the concentration can be between 100 g/l and saturation and is . usually between 150 and 600 g/l.
  • sodium rnolybdat ⁇ the concentration can be between 1 g/l and 100 g/l, and is usually between 3 g/l and 50 g/l .
  • Sodium tungstate rray be used at the same concentration as the sodium molybdate or in a higher concentration.
  • the hydroxy-carb ⁇ xylic acid may have from 2 to 8 carbon atoms, from one to six hydroxyl groups and from one to three carboxyl groups .
  • This rraterial rray also be presented to the solution as a water- soluble salt.
  • the hydroxy-carboxylic acid has the general formula C n H 2n O n +1 where n is an integer from 2 to 8.
  • Gluconat ⁇ s and heptonates are particularly suitable materials .
  • the concentration in which the hydroxy-carboxylic acid is present in the. solution rray be from 50 g/l to 800 g/l but for best results the concentration should be between 100 g/l and 400 g/l.
  • carboxylic acid serves to increase the maximum usable voltage and the current density which increase the rate of plating, and in addition its presence increases the resistance of the deposited alloy to cracking .
  • concentration of the carboxylic acid may be as low as 10 g/l and the rraximum concentration is about 100 g/l, above which the plating efficiency falls .
  • Mono-, di- or tri-carboxylic acids rray be used and they rray be presented to the solution as a water- soluble salt . Mixture of suitable materials may be used . Acetate and formate have proved to be effective.
  • the plating solution preferably has a pH of below about 4, most preferably below 3, since plating efficiency tends to fall if the pH is above this value. Best results are obtained within the pH range of 0.5 to 2.
  • a plating solution as made up may have a pH value outside this range, in which case acid or alkali may be added as appropriate to reach the desired value.
  • a plating of about 5 to 30 um thick. In practice the coating is preferably at least 10 um thick.
  • the operating voltage may range from 10 to 35 volts, preferably 18 to 20 volts.
  • the higher operating voltages are preferred if a higher content of molybdenum is required in the deposit.
  • the brush electrode comprises a handle 1 to one end of which is secured a carbon electrode 2 shown in ghost outline.
  • the handle 1 is of an electrical insulating material and a wire 3 passes from the electrode 2 through the handle 1.
  • a felt 4 covers the electrode 2 and is held on to the brush by an elastic band 5.
  • the felt 4 is 5 mm thick
  • the felt was formed of 75% polypropylene fibres and 25% nylon fibres which were consolidated by needle punching to a density of about 580 g.m .
  • the consolidated felt was then dipped in acrylic resin which was then heat cured to bond the fibres together.
  • the nylon fibres were of trinodular shape and the polypropylene fibres of rectangular shape.
  • the formed felt was then located on the electrode 2 and held there by the band 5.
  • the wire 3 is connected to one pole of a suitable power source and a metal body to be coated is connected to the other pole.
  • the electrode is connected as the anode and the metal body is connected as the cathode.
  • the brush electrode may also be used for cleaning or etching of the metal body in a known manner prior to plating, to give the body a surface which is better able to be coated, in which cases the electrode is connected as the cathode.
  • a pre-cleaned tool die was connected to the negative pole of a rectified alternating current power source giving about 20 volts .
  • the brush electrode was connected to the positive pole of the power source.
  • the tip of the brush electrode was then dipped into the plating solution so that the felt absorbed the solution, and the wetted electrode was then brushed over the tool die.
  • the amount of material deposited was monitored by means of an ampere-hour meter connected in the circuit .
  • the brush was 'kept moving, and was always kept wet with the solution.
  • An area of one square decametre was coated to a thickness ⁇ f about 1 ⁇ m in about 2 minutes.
  • the actual coating rate obtained depends upon the size of the brush electrode and operator skill, however, no problem was encountered in producing a coating of more than 12 um thick.
  • the coating was found to be a cobaltmolybdenum alloy containing between 6% and 12% molybdenum.
  • the coating was characterised by a very fine grain size, a low coefficient of friction and a satin finish. The presence of the coating extended the life of the die significantly.
  • Example 1 The solution of Example 1 was made up using 50 g/l of the molybda and the pH adjusted to 1.5 and similar good results were obtained.
  • the method of the invention makes it possible for an operator to travel from site to site doing coating jobs using portable apparatus.
  • the plating solution is stable under long-term storage conditions and is not susceptible to contamination or burning during brush plating.
  • the quality of the coating obtained by the method is at least as good as those obtained by bath electroplating techniques, and good quality coatings will be obtained despite the variations in solution pH and operating voltages typical of industrial practice.
  • the metal surfaces to be plated by the method of the invention will typically be of metal forming tools. Such tools may be dies and moulds and include hot forging dies and cold pressing tools. In a series of field evaluations plating different tools using the brush electrode and solutions of the invention, it was observed that when plating the tool surfaces to produce a cobalt-molybdenum alloy plating about 12 um thick, there was an average increase in die life of 60% for press tools and 50% for drop hammer dies. In the case of a hot forging die it was further noticed that the metal being formed flowed more easily over the die surface and as a result the forging t ⁇ mperatur ⁇ could be lowered giving additional saving on energy costs.
  • bits of metal from the metal being formed in the tool are left on the die surface and this metal pick up must be removed by hand polishing if the surface of metal being formed in the tool is not to be scored and otherwise damaged. This metal pick up is removed from time to time and the tool is then out of c ⁇ mmissio ⁇ before it can be reused.
  • plated dies it was found that there was a decrease in the time for which they were ⁇ out of c ⁇ mmission of about 78% compared to unplated tools.
  • a plated die needs little or no lubrication compared with an unplated die so saving labour in applying lubricant and also in cleaning the lubricant off at a later stage.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electroplating Methods And Accessories (AREA)

Abstract

Un balai electrode utilise dans l'electro-traitement d'une surface metallique, comprend une electrode (2) recouverte d'un materiau abrasif absorbant (4) forme de fibres synthetiques. Un materiau abrasif prefere est un feutre de polypropylene/nylon dans lequel les fibres sont consolidees par piquage et liees avec une resine acrylique. L'invention comprend une methode de depot d'un metal ou d'un alliage sur un corps metallique par utilisation d'un balai electrode qui permet d'obtenir des depots de bonne qualite sans avoir besoin de transporter la piece metallique dans une usine pour la traiter. Une solution utilisee avec cette methode, specialement stable dans de telles conditions, comprend des ions metalliques qui formeront un alliage, un acide hydroxy-carboxylique tel qu'un gluconate ou un heptonate pour complexer les ions metalliques, et un acide carboxylique tel que l'acide acetique, egalement pour complexer les ions metalliques. Les meilleurs resultats s'obtiennent lorsque le pH de la solution est entre 0,5 et 2.
PCT/GB1979/000027 1978-02-09 1979-02-09 Electro-traitement d'une surface metallique Ceased WO1979000608A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB515778 1978-02-09
GB2095478 1978-05-20
GB20954/78 1978-05-20

Publications (1)

Publication Number Publication Date
WO1979000608A1 true WO1979000608A1 (fr) 1979-08-23

Family

ID=26239691

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1979/000027 Ceased WO1979000608A1 (fr) 1978-02-09 1979-02-09 Electro-traitement d'une surface metallique

Country Status (3)

Country Link
EP (1) EP0003680A1 (fr)
DK (1) DK420079A (fr)
WO (1) WO1979000608A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2192642A (en) * 1986-07-19 1988-01-20 Ae Plc Electro deposition
GB2336161A (en) * 1998-04-06 1999-10-13 John Michael Lowe Providing conductive tracks on a printed circuit
US6939447B2 (en) 1998-04-06 2005-09-06 Tdao Limited Method of providing conductive tracks on a printed circuit and apparatus for use in carrying out the method
WO2016095896A1 (fr) * 2014-12-15 2016-06-23 Harting Ag & Co. Kg Procédé de dépôt électrolytque d'un revêtement de nickel sur un élément de contact électrique dans un bain électrolytique exempt de bore
WO2016095895A1 (fr) * 2014-12-15 2016-06-23 Harting Ag & Co. Kg Procédé de dépôt d'un alliage nickel-tungstène sur un élément de contact électrique

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4318585C1 (de) * 1993-05-03 1994-11-03 Schlattl Werner Bavaria Tech Punktschweißzange sowie Pinolenelement und Stromzuführung für diese Schweißzange
DE102010042642B4 (de) 2010-10-19 2013-12-12 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Verfahren und Vorrichtung zur galvanischen Beschichtung von Substraten und Solarzellen

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU180453A1 (ru) * М. А. Пилле Способ нанесения кобальтовых покрытий путем электронатирания
US2599178A (en) * 1950-03-10 1952-06-03 Wisconsin Alumni Res Found Electrodeposition of alloys of molybdenum with cobalt, nickel, and iron
US3725214A (en) * 1971-02-19 1973-04-03 Du Pont Chromium plating medium for a portable plating device
FR2176036A1 (fr) * 1972-03-14 1973-10-26 Sifco Ind Inc
DE2333069A1 (de) * 1972-07-03 1974-01-24 Oxy Metal Finishing Corp Elektrolytische abscheidung von glaenzenden nickel-eisen-ueberzuegen
GB1435267A (en) * 1973-11-05 1976-05-12 M & T Chemicals Inc Electrodeposition of nickel/iron or nickel/iron alloys
US4067781A (en) * 1977-01-10 1978-01-10 Rapids Felix R Method for electroplating

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU180453A1 (ru) * М. А. Пилле Способ нанесения кобальтовых покрытий путем электронатирания
US2599178A (en) * 1950-03-10 1952-06-03 Wisconsin Alumni Res Found Electrodeposition of alloys of molybdenum with cobalt, nickel, and iron
US3725214A (en) * 1971-02-19 1973-04-03 Du Pont Chromium plating medium for a portable plating device
FR2176036A1 (fr) * 1972-03-14 1973-10-26 Sifco Ind Inc
DE2333069A1 (de) * 1972-07-03 1974-01-24 Oxy Metal Finishing Corp Elektrolytische abscheidung von glaenzenden nickel-eisen-ueberzuegen
GB1435267A (en) * 1973-11-05 1976-05-12 M & T Chemicals Inc Electrodeposition of nickel/iron or nickel/iron alloys
US4067781A (en) * 1977-01-10 1978-01-10 Rapids Felix R Method for electroplating

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
Chemical Abstracts, volume 81, no. 16, issued October 21, 1974, ref. 98657, Columbus Ohio USA *
Chemical Abstracts, volume 85, no. 10, issued June 9, 1976, ref. 69981t, Columbus Ohio USA *
Cobalt 1975, no. 1, pages 17-28; article of Dennis and Still "The use of electro deposited cobalt alloy coatings to enhance the wear resistance of hot forging dies". *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2192642A (en) * 1986-07-19 1988-01-20 Ae Plc Electro deposition
GB2192642B (en) * 1986-07-19 1990-12-19 Ae Plc Process for the deposition of bearing alloys
GB2336161A (en) * 1998-04-06 1999-10-13 John Michael Lowe Providing conductive tracks on a printed circuit
US6524462B1 (en) 1998-04-06 2003-02-25 Technology Development Associate Operations Limited Method of providing conductive tracks on a printed circuit and apparatus for use in carrying out the method
GB2336161B (en) * 1998-04-06 2003-03-26 John Michael Lowe Method of providing conductive tracks on a printed circuit and apparatus for use in carrying out the method
US6939447B2 (en) 1998-04-06 2005-09-06 Tdao Limited Method of providing conductive tracks on a printed circuit and apparatus for use in carrying out the method
US6949171B2 (en) 1998-04-06 2005-09-27 Tdao Limited Method of providing conductive tracks on a printed circuit and apparatus for use in carrying out the method
WO2016095896A1 (fr) * 2014-12-15 2016-06-23 Harting Ag & Co. Kg Procédé de dépôt électrolytque d'un revêtement de nickel sur un élément de contact électrique dans un bain électrolytique exempt de bore
WO2016095895A1 (fr) * 2014-12-15 2016-06-23 Harting Ag & Co. Kg Procédé de dépôt d'un alliage nickel-tungstène sur un élément de contact électrique

Also Published As

Publication number Publication date
DK420079A (da) 1979-10-05
EP0003680A1 (fr) 1979-08-22

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