EP0435835B1 - Procédé d'électroplacage d'un alliage de zinc et dispositif utilisé dans ce but - Google Patents

Procédé d'électroplacage d'un alliage de zinc et dispositif utilisé dans ce but Download PDF

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Publication number
EP0435835B1
EP0435835B1 EP19900830585 EP90830585A EP0435835B1 EP 0435835 B1 EP0435835 B1 EP 0435835B1 EP 19900830585 EP19900830585 EP 19900830585 EP 90830585 A EP90830585 A EP 90830585A EP 0435835 B1 EP0435835 B1 EP 0435835B1
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EP
European Patent Office
Prior art keywords
gas diffusion
anode
zinc
bath
plating bath
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
EP19900830585
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German (de)
English (en)
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EP0435835A2 (fr
EP0435835A3 (en
Inventor
Nagakazu Furuya
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.)
Tanaka Kikinzoku Kogyo KK
Original Assignee
Tanaka Kikinzoku Kogyo KK
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Publication of EP0435835A2 publication Critical patent/EP0435835A2/fr
Publication of EP0435835A3 publication Critical patent/EP0435835A3/en
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    • 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
    • C25D3/565—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight 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
    • C25D17/00—Constructional parts, or assemblies thereof, of cells for electrolytic coating
    • C25D17/10—Electrodes, e.g. composition, counter electrode

Definitions

  • the present invention relates to a process for electro plating a zinc alloy.
  • the life of the electrode is as short as several thousand hours because the oxygen evolution occurs on the iridium or platinum-plated anode.
  • the valency of the iron ion in the plating bath increases in spite of the supplement of the plating solution hecause the iron ion is oxidized on the anode. For this reason, the plating solution in the plating bath is circulated to an electrolytic reduction apparatus equipped with an ion exchange membrane to reduce Fe 3+ to Fe2+.
  • accession number 87/296109 corresponding to Japanese application JP-A-62208554, a gas diffusion electrode composed of a laminated film having a reaction layer and a gas diffusion layer bonded together for use in fuel cells, electrochemical reactions and as anodes for electroplating, is disclosed.
  • the anode cannot be used if the mechanical strength is insufficient.
  • the anode may be scratched and sparks when the anode contacts the steel.
  • An object of the present invention is to provide a process for electroplating a steel with a zinc alloy using a gas diffusion electrode apparatus which does not require a frequent discharge of the plating solution.
  • a further object of the invention is to provide a process wherein scratches and sparks are prevented.
  • the process for electroplating a zinc-iron alloy according to the present invention for overcoming the above problems comprises disposing in an electrolytic cell a gas diffusion electrode apparatus comprising a plurality of gas diffusion electrodes which function as an anode and are formed by a gas diffusion layer and a reaction layer being attached together, and an electroconductive reinforcing frame to which the gas diffusion electrodes are supported; forming a zinc alloy plating bath on the reaction layer side of the electrolytic cell which functions as anode chamber; supplying electricity to the gas diffusion electrodes through the reinforcing frame while supplying a hydrogen gas to the electrolytic cell of the gas diffusion layer side; and electroplating a steel with the zinc alloy by passing the steel as a cathode material through the zinc alloy bath.
  • the gas diffusion electrode is employed as an anode and the hydrogen gas is supplied to the gas diffusion layer side of the gas diffusion electrode to make an anode reaction of the plating bath to a hydrogen oxidation reaction, no oxygen evolves on the anode in case of the sulfate bath and no chlorine gas evolves on the anode so that a smooth and gorgeous zinc alloy plating layer without burns can be formed on the steel passing through the plating bath.
  • ions in the plating bath such as iron, cobalt, manganese and the like are not oxidized on the anode, and even if they are oxidized on the anode to be contaminated in the plating bath in the form of their ions, these ions are reduced by the gas diffusion electrode to lower their ionic valency so that the zinc ion and the pH of the plating bath are never unbalanced. Accordingly, the plating bath can be effectively employed without the discharge of the plating solution, and the plating thickness of the zinc-iron alloy applied to the steel does not change and the surface does not partially become rough.
  • the gas diffusion electrodes are supported in the electroconductive reinforcing frame employed in the process for electroplating such an alloy as zinc-iron, zinc-cobalt, zinc-manganese and the like as mentioned before, the mechanical strength of the gas diffusion electrode functioning as an anode is elevated. Therefore, if the steel moves at high speed in the small plating bath, the gas diffusion electrode is never flapped nor scratched and does not generate a spark.
  • 1 designates a rectangular gas diffusion electrode.
  • the gas diffusion electrode 1 is formed by a gas diffusion layer 2 and a reaction layer 3 attached together, the gas diffusion layer 2 consisting of hydrophobic carbon black and polytetrafluoroethylene, and the reaction layer 3 consisting of hydrophilic carbon black carrying a platinum catalyst, hydrophobic carbon black and polytetrafluoroethylene.
  • a p]urality of the gas diffusion electrodes 1, 10 electrodes in this embodiment are installed and supported in an electroconductive reinforcing frame made of titanium, copper, stainless and the like, in a lattice reinforcing frame 4 made of titanium in this embodiment.
  • a protection member 5 is formed on the front surface of the reinforcing frame 4 at the reaction layer 3 side of the gas diffusion electrode 1.
  • a gas diffusion electrode apparatus 9 employing the thus constructed gas diffusion electrode was disposed as an anode in an electrolytic cell 10, and a chloride bath 12 was filled in the cell chamber 11 formed on the reaction layer 3 side of the gas diffusion electrode 1, which defined an anode chamber 13.
  • a hydrogen gas was successively introduced into the cell chamber 13 on the gas diffusion layer 2 side of the gas diffusion electrode 1, from an inlet port 14 so as to successively supply the hydrogen gas to the gas diffusion layer 2 side of the gas diffusion electrode apparatus 9 and to simultaneously discharge the hydrogen gas from the gas diffusion electrode 1 through a discharge port 15 of the cell chamber 13.
  • the current was passed to the respective gas diffusion electrodes 1 through the reinforcing frame 4.
  • a steel foll 16 as a cathode was passed through the plating bath 12 of the cell chamber 11 at a relatively high speed.
  • the gas diffusion electrode 1 By using the gas diffusion electrode 1 as an anode while supplying the hydrogen gas to the gas diffusion layer 2 side of the gas diffusion electrode 1 so as to make the anode reaction of the chloride plating bath 12 to be a hydrogen oxidation reaction, no chlorine gas was evolved on the anode.
  • the zinc-iron alloy layer plated on the steel 16 was examined to have a smooth and gorgeous surface, without burns. When the steel was successively passed through the cell to effect the electroplating of the zinc-iron alloy, no iron ion was oxidized on the anode from Fe 2+ to Fe 3+. Even if Fe3+ is contaminated in the plating bath 12, the zinc, the iron ion and the pH does not become unbalanced because Fe3+ is reduced on the gas diffusion electrode 1 to Fe2+.
  • the circulation of the plating solution of the plating bath 12 to an electrolytic reduction apparatus equipped with an ion exchange membrane is unnecessary, and the plating solution of the plating bath 12 can be effectively used without being discharged. No variation of the thickness of the zinc-iron alloy layer plated on the steel 16 and no partial roughness of the surface is observed.
  • the gas diffusion electrodes 1 functioning as an anode are supported in the reinforcing frame 4, providing a high mechanical strength, the electrodes are not flapped nor bent even when the steel 16 moves in the small plating bath 12 at a speed as high as 200 m/min.
  • a gas diffusion electrode 1 having a length of 100 mm and a width of 100 mm was formed by a gas diffusion layer 2 with a thickness of 500 ⁇ m and a reaction layer 3 with a thickness of 100 ⁇ m, attached together.
  • the gas diffision layer 2 consisted of hydrophobic carbon black of average particle size 420 ⁇ and polytetrafluoroethylene of average particle size 0.3 ⁇ m.
  • the reaction layer 3 consisted of hydrophilic carbon black of average particle size 420 ⁇ , carrying a platinum catalyst load of 0.56mg/cm2 , hydrophobic carbon black of average particle size 420 ⁇ and polytetrafluoroethylene of average particle size 0.3 ⁇ m.
  • Ten gas diffusion electrodes 1 were installed and supported in an electroconductive reinforcing frame 4 made of titanium.
  • a protection member 5 was equipped on the front surface of the reinforcing frame 4 at the reaction layer 3 side of the gas diffusion electrode 1.
  • a gas diffusion electrode apparatus 9 was disposed in an electrolytic cell 10, and a chloride bath 12 consisting of 50g/liter-FeCl2 .
  • a hydrogen gas was successively introduced into the cell chamber 13, on the gas diffusion layer 2 side of the gas diffusion electrode 1.
  • current was flown to the respective gas diffusion electrodes 1 through the latticed reinforcing frame 4.
  • a steel cathode 16 was passed through the plating bath 12 of the cell chamber 11 at a speed of 200m/min., at a current density of 150 A/dm2 and a bath voltage of 8.6 V so that the steel 16 was electroplated with a zinc-iron alloy layer having a thickness of 4 ⁇ m.
  • the gas diffusion electrode 1 was employed as an anode while supplying hydrogen gas to the gas diffusion layer 2 side of the gas diffusion electrode 1 so as to make the anode reaction of the chloride plating bath 12 to be a hydrogen oxidation reaction. No chlorine gas was evolved on the anode.
  • the zinc-iron alloy layer plated on the steel 16 was examined to have a smooth and gorgeous surface without burns. When the steel was successively passed to effect the electroplating of the zinc-iron alloy, no iron ion was oxidized on the anode from Fe2+ to Fe3+. Even if Fe3+ was contaminated in the plating bath 12, the zinc, the iron ion and the pH did not become unbalanced because Fe3+ was reduced on the gas diffusion electrode 1 to Fe2+.
  • the gas diffusion electrodes 1 functioning as an anode were supported in the reinforcing frame 4 so as to elevate the mechanical strength, the electrodes were not flapped nor bent even when the steel 16 moved in the narrow plating bath 12 at a speed as high as 200 m/min. Since the protection member 5 was formed on the front surface of the reinforcing frame 4, the moving steel 16 was never in contact with the gas permeable electrode 1 so that scratches and sparks were not produced.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
  • Electroplating Methods And Accessories (AREA)

Claims (2)

  1. Procédé de dépôt électrolytique d'un alliage de zinc sur une cathode en acier se déplaçant rapidement à travers un bain de dépôt électrolytique d'alliage de zinc dans une cellule munie d'une anode à diffusion gazeuse ayant la forme d'un film stratifié fait d'une couche de réaction et d'une couche de diffusion des gaz liées ensemble, caractérisé en ce qu'il comprend les étapes consistant à:
    - supporter ladite anode à diffusion gazeuse dans un cadre de renfort électroconducteur à mailles et envoyer un courant à ladite anode à diffusion gazeuse par l'intermédiaiare dudit cadre de renfort,
    - empêcher le contact glissant entre ladite cathode qui se déplace rapidement et une surface en vis-à-vis de ladite anode à diffusion gazeuse tout en évitant un pliage de ladite anode à diffusion gazeuse grâce à un élément de protection à mailles placé au-dessus de ladite anode à diffusion gazeuse et fixé audit cadre de renfort et de soutien.
  2. Procédé selon la revendication 1, dans lequel ledit bain de dépôt électrolytique est un bain de chlorures et ladite cathode en acier se déplace dans le bain à une vitesse aussi élevée que 200 m/min.
EP19900830585 1989-12-15 1990-12-14 Procédé d'électroplacage d'un alliage de zinc et dispositif utilisé dans ce but Expired - Lifetime EP0435835B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP325562/89 1989-12-15
JP32556289A JPH03188299A (ja) 1989-12-15 1989-12-15 亜鉛合金電気めっき方法及びそれに使用するガス拡散電極装置

Publications (3)

Publication Number Publication Date
EP0435835A2 EP0435835A2 (fr) 1991-07-03
EP0435835A3 EP0435835A3 (en) 1991-11-13
EP0435835B1 true EP0435835B1 (fr) 1994-08-03

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900830585 Expired - Lifetime EP0435835B1 (fr) 1989-12-15 1990-12-14 Procédé d'électroplacage d'un alliage de zinc et dispositif utilisé dans ce but

Country Status (3)

Country Link
EP (1) EP0435835B1 (fr)
JP (1) JPH03188299A (fr)
DE (1) DE69011304T2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6280871B1 (en) 1999-10-12 2001-08-28 Cabot Corporation Gas diffusion electrodes containing modified carbon products
US7541308B2 (en) 2001-04-11 2009-06-02 Cabot Corporation Fuel cells and other products containing modified carbon products

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03202489A (ja) * 1989-12-29 1991-09-04 Nkk Corp マンガンおよびマンガン合金めつき方法
US6399202B1 (en) 1999-10-12 2002-06-04 Cabot Corporation Modified carbon products useful in gas diffusion electrodes
JP4822268B2 (ja) * 2005-04-19 2011-11-24 ユケン工業株式会社 回収型電気亜鉛めっき方法および装置
CN104073862A (zh) * 2014-07-11 2014-10-01 张钰 一种用于碱性锌镍合金电镀的不溶性阳极装置

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3326723A (en) * 1963-01-04 1967-06-20 Leesona Corp Fuel cell electrode construction
JPS62208554A (ja) * 1986-03-07 1987-09-12 Tanaka Kikinzoku Kogyo Kk ガス拡散電極及びその製造方法
NL8801511A (nl) * 1988-06-14 1990-01-02 Hoogovens Groep Bv Werkwijze voor het elektrolytisch bekleden van een metalen substraat met een metalen bekledingslaag.

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6280871B1 (en) 1999-10-12 2001-08-28 Cabot Corporation Gas diffusion electrodes containing modified carbon products
US6881511B1 (en) 1999-10-12 2005-04-19 Cabot Corporation Gas diffusion electrodes containing modified carbon products
US7541308B2 (en) 2001-04-11 2009-06-02 Cabot Corporation Fuel cells and other products containing modified carbon products

Also Published As

Publication number Publication date
JPH03188299A (ja) 1991-08-16
EP0435835A2 (fr) 1991-07-03
EP0435835A3 (en) 1991-11-13
DE69011304D1 (de) 1994-09-08
DE69011304T2 (de) 1994-11-17

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