US3691049A - Wire and strip line electroplating - Google Patents

Wire and strip line electroplating Download PDF

Info

Publication number
US3691049A
US3691049A US28758A US3691049DA US3691049A US 3691049 A US3691049 A US 3691049A US 28758 A US28758 A US 28758A US 3691049D A US3691049D A US 3691049DA US 3691049 A US3691049 A US 3691049A
Authority
US
United States
Prior art keywords
anode
zinc
support
bath
tin
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.)
Expired - Lifetime
Application number
US28758A
Other languages
English (en)
Inventor
Frederick Walter Eppensteiner
Richard E Woehrle
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.)
M&T Chemicals Inc
Original Assignee
M&T Chemicals Inc
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 M&T Chemicals Inc filed Critical M&T Chemicals Inc
Application granted granted Critical
Publication of US3691049A publication Critical patent/US3691049A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C25D7/06—Wires; Strips; Foils
    • C25D7/0614—Strips or foils
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D17/00—Constructional parts, or assemblies thereof, of cells for electrolytic coating
    • C25D17/10—Electrodes, e.g. composition, counter electrode
    • 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
    • C25D3/22—Electroplating: Baths therefor from solutions of zinc
    • 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
    • C25D3/30—Electroplating: Baths therefor from solutions of tin
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C25D7/06—Wires; Strips; Foils
    • C25D7/0614—Strips or foils
    • C25D7/0642—Anodes

Definitions

  • this invention relates to electroplating of a metal substrate such as steel in the form of a wire or a strip, with a plating metal including such metals as zinc and tin. More particularly, this invention relates to the high speed electroplating of such metal substrates in the form of wire or strips in a manner so that the final strip is plated with a thickness of metal appropriate for certain commercial applications while at the time the plating process is sufficiently fast and efficient to produce the finally coated metal wire or strip to be commercially competitive with such prior art processes as hot-dip galvanizing of strip steel, for example.
  • one method is to stop-01f one side of the steel strip with a subsatnce which prevents one side of the steel strip from being coated with zinc when it passes through the molten zinc bath.
  • This stop-off coating is later stripped from the steel strip so that the final product is a steel strip having a zinc coating only on one side.
  • the uncoated side is then arranged to be the outside surface for automobiles, for example, where applications of paint are made on the final assembled parts of the automobile.
  • Other methods for avoiding the coating of one side of the continuous steel strip include applying a doctor blade to one side of the steel strip as it exists from the molten zinc bath to scrape off the molten zinc coating on the one side prior to the time that the coating hardens.
  • this doctor blade is utilized in conjunction with a flame application to the coating in order to maintain it in a liquid state long enough for the doctor blade to be effective in removing the zinc coating from the one side of the steel strip.
  • the prior art electroplating methods have proved unsatisfactory in certain instances in which mass produced quantities of steel strip are desired for such applications as automobile parts.
  • the thickness of the coating is about 0.000084 inch.
  • the reason for this is that the current density which must be utilized with a zinc sulfate bath is such that this is the thickness which is the most economical from such an operation.
  • This thickness is undesirable for automotive purposes, for example, merely because it does not provide satisfactory protection from the oxidation environment ordinarily encountered by automotive parts.
  • the desired thickness of such a coating is about 0.00067 inch which would be satisfactory for automotive needs, for example.
  • One way to overcome this problem of low current density causing extremely slow speeds in order to obtain the proper thickness of coating is to utilize a bath with higher limiting current density and higher conductivity than can be obtained with the usual zinc sulfate bath.
  • a chloride zinc bath can be operated at much higher current densities than is the case with the usual zinc sulfate bath. Because of the higher current densities, the strip line can be operated at a much faster rate while still achieving a desirably thick plate.
  • the anode in this case zinc
  • the anode is disposed along the bottom of the plating tank containing the electrolyte solution.
  • the anode must be supported and in the past carbon has been utilized as the support for the anode.
  • commercially acceptable zinc sulfate bath no problem arises merely because there is no chlorine evolution.
  • the highest operating current density is still so low that in order to provide the proper plating thickness on the steel strip the cost of the operation becomes prohibitive for mass production utilization.
  • the chloride zinc bath is used, by contrast, there is electrochemical reaction between the bath and the carbon anode support at high current densities, thus producing the chlorine evolution noted above. In attempting to electroplate zinc in a strip line operation neither bath has proved completely satisfactory for commercial operations.
  • the combination anode-anode support in accordance herewith provides much more satisfactory and efiicient electroplating merely because there is much lower contact resistance to the current passing between the anode and the anode support combined with no current loss from the support to the solution, thus providing much more efiicient electroplating operation.
  • the invention herein has proved particularly appropriate and highly desirable for electroplating of zinc in strip line electroplating, it is to be understood that this invention is not limited merely to the electroplating of zinc. It has been found that the invention, in accordance herewith, has proved highly satisfactory, also, for strip line tin electroplating.
  • a tin bath containing halides as well known, with a tin anode and an anode support comprised essentially of tantalum there is a striking reduction almost to the point of elimination of oxidation of stannous to stannic tin on the anode support, while simultaneously providing for the use of high current densities and the absence of side reactions.
  • a further object of this invention is to provide methods and apparatus for strip line electroplating of tin in combination with an acid tin bath in which the accumulation of bi-polar tin on the anode support is substantially avoided because of prevention of oxidation in solution of stannous to stannic tin on the support, simultaneously with a substantial reduction in the amount of tin accumulating in the sludge in such baths.
  • applied DC line voltages of up to 40 volts may be used in accordance herewith for tin electroplating for example, with substantial elimination of current loss and no breakdown of the oxide film formed at the solution-support interface. This contrasts greatly with the usual applied line voltage in tin strip line electroplating of between about 2124 volts.
  • FIG. 1 is a somewhat diagrammatic longitudinal sectional view of apparatus embodying and for accomplishing this invention and showing an arrangement of anode structure, in accordance herewith, as it is disposed in a strip line for electroplating; and
  • FIG. 2 is a section along the line II--II of FIG. 1.
  • an illustrative embodiment of apparatus for practicing this invention is somewhat diagrammatically depicted as having a strip line electroplating tank in which is disposed a plaitng solution 12, the upper level of which is designated 11.
  • Tank 10 is of any material nonreactive to the plating solution, such as, for example, a metallic tank with a non-reactive coating, all as well known.
  • this solution will depend upon which metal is being electroplated on the strip passing through the apparatus.
  • a strip 13 is passing continuously through the plating solution 12 along the upper level 11 thereof, the strip 13 being the metal which is to be electroplated.
  • strip 13 travels between metal contact roll 26 and backup roll 28.
  • strip 13 travels between metal contact roll 30 and backup roll 32.
  • current is supplied at anode terminal 22, the strip 13 is the cathode and the circuit is completed through contact rollers 26 and 30.
  • the anode is in the form of a plurality of individual anodes 14.
  • Anodes 14 are arranged along the bottom of the apparatus, the anodes being of the metal which is to be plated on strip 13 moving continuously along above the anode.
  • the anodes are arranged in the form of individual pieces or bricks which are added to the left hand side in FIG. 2 and are gradually moved toward the right hand side.
  • the anode support 16 is arranged in inclined fashion below the anodes in order to provide for or accommodate the different sized pieces of anode as they are moved along the anode support from the left to the right, as is shown in FIG. 2.
  • the anode support 16 is comprised essentially of a member selected from the group consisting of tantalum, niobium, and mixtures thereof.
  • anode support 16 is a further anode sub-support 18 of the metal being plated which is covered or protected from solution except for the interface which is the bottom support surface all in wellknown manner.
  • Upright 21 is in contact with sub-support 18, and as in the embodiment shown is an extension of sub-support 18, and has disposed thereon the positive terminal 22 for connecting the apparatus to a source of current, as well known, but not shown for clarity, because the source of current does not form a part of the invention.
  • support 16, sub-support 18 and extension 21 can be a single component, all in wellknown manner.
  • the single component may be comprised essentially of a member selected from the group consisting of tantalum, niobium and mixtures thereof, or the entire surface of the single component may be coated with such member, in accordance herewith.
  • the anode-anode support structure is disposed on blocks 20 which may be of any configuration as long as they serve to hold the structure away from the floor of tank 10.
  • Blocks 20 may be of any well-known material which is non-reactive to the plating solution, such as Micarta, for example.
  • strip 13 is the cathode and receives a coating of the metal from solution 12.
  • an oxide coating is formed at the anode support 16-solution 12 interface, such as 23 in FIG. 1 or 24 in FIG. 2. Because of this, no current passes through this interface. Thus, the current takes the path of least resistance to the anodes 14 through the solution 12 to cathode 13 which is the strip being plated.
  • anode support 16 is no electrochemical reaction between anode support 16 and the solution 12, which may be a chloride zinc bath, thus preventing chlorine evolution by electrochemical reaction of the solution 12 with the anode support 16 comprised essentially of a member selected from the group consisting of tantalum, niobium, and mixtures thereof.
  • strip line voltages are usually 12 volts and above, and therefore, if the anode becomes polarized titanium would dissolve, thus contaminating the bath solution.
  • tantalum for example, would not.
  • Tables II and III below show the individual readings for niobium and tantalum, respectively, which provide the data for Table I.
  • a 4" x 5 x .032 sheet of the particular niobium and/or tantalum material to be tested was prepared by cleaning with various commercial cleaners and afiixed with a lead for measuring the voltage drop across the sheet when it is placed between the slab zinc anode and the zinc anode sub-support below the particular metallic tantalum and/or niobium support interposed therebetween in the sandwich structure as described and illustrated above.
  • the source of current to the test apparatus was from a rectifier having a range of 0-500 amps.
  • the solution placed in the tank was a chloride zinc bath containing g./l. ZnCl and g./l.
  • Table V is an indication of the results achieved in these tests.
  • the voltage is measured between the zinc anode and the tantalum support.
  • various amperages were passed and voltage measurements were taken at each amperage level to make a comparison of contact resistance. As is readily apparent from a review of Table V, there is relatively little resistance.
  • Tables VII and VIII below are further illustrations of the results achieved in accordance herewith in which tantalum life tests were carried out with the same sandwich structure noted above and with the same zinc chloride solution in the amount of 60 liters being used as the bath. As is apparent in this life test, the amperage was maintained at a constant level over a period of time.
  • ATZT and ATZB is an indication of contact resistance, with ATZT being the voltage difference between the zinc anode and the tantalum support, while ATZB is the voltage difference between the tantalum support and the zinc sub-support.
  • Table VII the voltmeter used was not sensitive enough to detect voltage, whereas the ATZB readings in Table VIII were taken with the more sensitive Keithley 6100 Electrometer.
  • Table IX is an indication of the results achieved in accordance herewith when a zinc sulfate-type bath is used for electroplating zinc in a strip line operation and shows the increased efficiency with the arrangement in accordance herewith in those instances where a zinc sulfate bath may be more appropriate than a zinc chloride bath for certain applications in which speed and quantitative production are not critical.
  • a polyvinyl chloride coated tank was used measuring 1 x 1' x 2.5. 53 liters of a plating solution was used containing 236 g. /l. ZnSO -H O, 61 g./l. MgSO -7H O, and 72 g./l. Na SO
  • the zinc anode measured 15.5" x 1.75" x 1.25" with the anode area being 93 square inches.
  • the various designations for Table IX are:
  • the addition agent may be any well-known material such as, for example, a polyethylene glycol composition such as that disclosed in U.S. Patent 2,457,152.
  • the tin anode to tantalum support voltages were 0.3 to 0.7 volt while the tin anode to carbon support voltages were normally higher at 0.4 to 1.35 volts.
  • the bath utilized was 500 ml. of tin plating bath containing halides as follows:
  • the temperature during the tests was maintained at between about 144150 F. (6265.6 C.) and the pH was about 3.0.
  • baths containing halogens may be utilized for electroplating substantially in the absence of halogen gas evolution thus making the environment of such operations acceptable for the operators thereof.
  • there is substantially reduced resistance to current passing between the various interfaces of the sandwich structure thus enhancing the overall efiiciency of operations utilizing the structure herein.
  • tin strip line electroplating utilizing the structure herein there is a reduction in the loss of tin in solution thus reducing the amount of tin necessary to achieve a particular amount of plate.
  • An apparatus of the character described for the wire and strip line electroplating of metals having a plating tank with a plating bath disposed therein, as the cathode a metallic substrate to be coated and arranged to continuously move through said tank; and a source of plating current, the combination which comprises an anode of the metal to be plated; and a support for said anode comprised essentially of at least one member selected from the group consisting of niobium, tantalum and mixtures thereof; said support and said anode being connected to said source for providing passage of plating current from the anode-bath interface to said cathode substantially in the absence of the passage of current at the support-bath interface.
  • An apparatus of the character described for the wire and strip line electroplating of metal having a plating tank with a plating bath disposed therein, as the cathode a metallic substrate to be coated and arranged to continuously move through said tank; and a source of plating current, the combination which comprises an anode of the metal to be plated; and a support for said anode at least the surface of which is comprised essentially of a member selected from the group consisting of niobium, tantalum, and mixtures thereof; said support and said anode being connected to said source for providing passage of plating current from the anode-bath interface to said cathode substantially in the absence of the passage of current at the support-bath interface.
  • Apparatus as recited in claim 2. which also includes a sub-support of the metal to be coated disposed adjacent said support, and in which the said sub-support, said support and said anode are arranged in sandwich fashion.
  • bath includes sodium ferrocyanide, sodium acid fluoride, sodium fluoride, stannous chloride, sodium chloride and an addition agent.

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)
  • Electroplating And Plating Baths Therefor (AREA)
US28758A 1970-04-15 1970-04-15 Wire and strip line electroplating Expired - Lifetime US3691049A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US2875870A 1970-04-15 1970-04-15

Publications (1)

Publication Number Publication Date
US3691049A true US3691049A (en) 1972-09-12

Family

ID=21845259

Family Applications (1)

Application Number Title Priority Date Filing Date
US28758A Expired - Lifetime US3691049A (en) 1970-04-15 1970-04-15 Wire and strip line electroplating

Country Status (8)

Country Link
US (1) US3691049A (enrdf_load_stackoverflow)
BR (1) BR7102209D0 (enrdf_load_stackoverflow)
CA (1) CA947227A (enrdf_load_stackoverflow)
DE (1) DE2117802A1 (enrdf_load_stackoverflow)
FR (1) FR2086098B1 (enrdf_load_stackoverflow)
GB (1) GB1296187A (enrdf_load_stackoverflow)
NL (1) NL7104909A (enrdf_load_stackoverflow)
ZA (1) ZA711509B (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4505785A (en) * 1981-02-24 1985-03-19 Nippon Kokan Kabushiki Kaisha Method for electroplating steel strip
US5478457A (en) * 1988-10-06 1995-12-26 Catteeuw; Mario Apparatus for the continuous electrolytic treatment of wire-shaped objects
WO1999010562A3 (de) * 1997-08-21 1999-05-27 Atotech Deutschland Gmbh Verfahren zur wartung von durchlaufgalvanisieranlagen

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4686013A (en) * 1986-03-14 1987-08-11 Gates Energy Products, Inc. Electrode for a rechargeable electrochemical cell and method and apparatus for making same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4505785A (en) * 1981-02-24 1985-03-19 Nippon Kokan Kabushiki Kaisha Method for electroplating steel strip
US5478457A (en) * 1988-10-06 1995-12-26 Catteeuw; Mario Apparatus for the continuous electrolytic treatment of wire-shaped objects
WO1999010562A3 (de) * 1997-08-21 1999-05-27 Atotech Deutschland Gmbh Verfahren zur wartung von durchlaufgalvanisieranlagen

Also Published As

Publication number Publication date
BR7102209D0 (pt) 1973-04-10
NL7104909A (enrdf_load_stackoverflow) 1971-10-19
FR2086098A1 (enrdf_load_stackoverflow) 1971-12-31
GB1296187A (enrdf_load_stackoverflow) 1972-11-15
FR2086098B1 (enrdf_load_stackoverflow) 1975-07-04
ZA711509B (en) 1971-11-24
CA947227A (en) 1974-05-14
DE2117802A1 (de) 1971-11-04

Similar Documents

Publication Publication Date Title
US2708181A (en) Electroplating process
US3511758A (en) Method of preventing etch on steel and iron in plating baths
US2446331A (en) Electrodeposition of aluminum
US20150354077A1 (en) Electrodeposition of chromium from trivalent chromium using modulated electric fields
KR100253607B1 (ko) 불용해성전극구성물질
US3989604A (en) Method of producing metal strip having a galvanized coating on one side
US3988216A (en) Method of producing metal strip having a galvanized coating on one side while preventing the formation of a zinc deposit on cathode means
US3554881A (en) Electrochemical process for the surface treatment of titanium,alloys thereof and other analogous metals
US4155816A (en) Method of electroplating and treating electroplated ferrous based wire
US4249999A (en) Electrolytic zinc-nickel alloy plating
US3691049A (en) Wire and strip line electroplating
US4127450A (en) Method for pretreating surfaces of steel parts for electroplating with organic or inorganic coatings
US3954571A (en) Wire and strip line electroplating
Sibert et al. Electrodeposition of titanium on base metals
Dobrev et al. Processes during the electrorefining and electrowinning of lead
ES8202597A1 (es) Dispositivo para la metalizacion por electrolisis
US4064034A (en) Anode structure for wire and strip line electroplating
US3775260A (en) Electroplating aluminum
US3412000A (en) Cathodic protection of titanium surfaces
Jović et al. Qualitative and quantitative assessment of phases in electrodeposited Ni+ Cd alloys by the ALSV technique
US3837879A (en) Removing of worn coating from metal electrodes
Glazunov Determination of the phase structure of metallic protective coatings by anodic dissolution
JPH057474B2 (enrdf_load_stackoverflow)
US3334030A (en) Production of electrolytic tinplate
US3843494A (en) Process for preparing zinc coated ferrous metal substrates having improved resistance spot welding characteristics