JPH07173695A - Electroplating device using gas diffusion electrode - Google Patents

Abstract

PURPOSE:To industrially efficiently apply electroplating to a metallic strip moving continuously in a horizontal direction by forming gas diffusion electrodes as insoluble anodes within a horizontal type electroplating tank. CONSTITUTION:This electroplating device consists of an electrode holder chamber 2 in which the metallic strip 1 is horizontally movable, the gas diffusion electrode plates 4 which are so disposed as to segment the inside of this electrode holder chamber 2 in a horizontal direction above and below the metallic strip 1 across this metallic strip in the electrode holder chamber 2, an electroplating chamber 5 and gas chamber 6 which are segmented by these gas diffusion electrode plates 4, a pair of upper and lower rolls 12, 13 which are disposed in proximity to the inlet and outlet of the electroplating chamber 5 and sealing plates 14 which are disposed between these rolls 12, 13 and the holder chamber 2. The electroplating chamber 5 is provided with nozzles 7 for supplying the plating liquid and plating liquid discharge ports 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal strip which is continuously moved in the horizontal direction, for electroplating continuously on at least one surface of the metal strip by using a gas diffusion electrode as an anode. The present invention relates to an electroplating apparatus using a gas diffusion electrode.

[0002]

2. Description of the Related Art As an electroplating bath for industrially producing electroplated metal strips, a sulfuric acid electroplating bath mainly containing a sulfate of a metal to be electrodeposited and a chloride of a metal to be electrodeposited are generally used. Or a mixed electroplating bath of a sulfuric acid electroplating bath and a chloride electroplating bath.

Comparing the sulfuric acid electroplating bath and the chloride electroplating bath, the chloride electroplating bath has a higher electric conductivity than the sulfuric acid electroplating bath, so that the electric power cost is low and the limiting current density is high. It has the advantages that plating can be performed and that the electrolysis efficiency is high. Therefore, the chloride electroplating bath has a very advantageous condition when performing electroplating with a high current density, which is becoming the mainstream in recent years.

When performing electroplating using a metal strip as a cathode, the self-fluxing electrode, in which the electrode itself elutes into the plating bath to replenish metal ions in the plating bath, the anode itself decreases, and a gas from the anode Occurs, and the anode itself does not decrease. When a self-fluxing electrode is used as an anode, the electrode must be frequently replaced when operating at a high current density, so in recent years, for example, a platinum electrode or an electrode coated with an oxide on a titanium plate is used. The use of insoluble electrodes is becoming mainstream.

However, using the insoluble anodes described above and electroplating metal strips in a chloride electroplating bath presents the problem of producing harmful chlorine gas from the insoluble anodes. Even if a sulfuric acid electroplating bath is used to avoid the generation of such chlorine gas, a large amount of oxygen gas generated from the anode is always present between the anode and the cathode. The electric conductivity of the metal may decrease, and the plating film itself may be adversely affected.

As a means for solving the above-mentioned problem, Japanese Patent Laid-Open No. 3-188299 discloses an anode comprising a gas diffusion electrode in which a gas diffusion layer and a reaction layer are joined in a vertical electroplating bath. An electroplating device (hereinafter referred to as prior art) that is arranged vertically from the upper part to the lower part so as to partition the inside of the tank, supplies hydrogen gas from the back surface, and oxidizes this hydrogen gas to diffuse it in the plating bath. ) Is disclosed. According to the prior art, the anodic reaction of the electroplating bath is
It becomes a hydrogen oxidation reaction. Therefore, chlorine gas and oxygen gas are not generated, and a smooth and non-burning plating film can be formed on the surface of the metal strip.

[0007]

However, the prior art only conceptually shows an apparatus in which a gas diffusion electrode is arranged in a vertical type electroplating tank, and it is often used in actual operation. When the gas diffusion electrode is arranged in the horizontal type electroplating tank and electroplating is performed by the gas diffusion electrode, there are many problems in the specific engineering. Therefore, industrial electroplating of a metal strip that moves continuously in the horizontal direction using a gas diffusion electrode as an anode in a horizontal electroplating tank has not yet been realized.

Therefore, an object of the present invention is to solve the above-mentioned problems and to use a gas diffusion electrode as an insoluble anode in a horizontal type electroplating tank for a metal strip which moves continuously in the horizontal direction. An object of the present invention is to provide an electroplating apparatus using a gas diffusion electrode, which can efficiently and efficiently perform electroplating.

[0009]

SUMMARY OF THE INVENTION The electroplating apparatus of the present invention has a metal strip inlet opening at one end and a metal strip outlet at the other end through which the metal strip moves substantially horizontally. In the horizontal electrode holder chamber having an opening, and in the horizontal electrode holder chamber, the metal strip moving in the holder chamber is sandwiched, and a predetermined interval is provided above and below the holder. A gas diffusion electrode plate provided so as to partition the chamber in the horizontal direction, and a gas diffusion electrode plate partitioned by the gas diffusion electrode plate and formed inside the gas diffusion electrode plate in the holder chamber, the electroplating solution therein. A horizontal electroplating chamber, and a gas chamber formed outside the gas diffusion electrode plate in the holder chamber, in which hydrogen gas circulates, A pair of rolls provided in proximity to each of the inlet opening and the outlet opening of the flat electroplating chamber so as to be orthogonal to the moving direction of the metal strip and contacting both upper and lower surfaces of the metal strip; 1
A seal plate provided between the pair of rolls and the electrode holder chamber so as to cover a surface of the pair of rolls facing the electrode holder chamber, and one end side of the electroplating chamber is provided. A nozzle for supplying an electroplating solution into the electroplating chamber is provided, and a plating solution discharge port for discharging the electroplating solution supplied into the electroplating chamber is provided at the other end of the electroplating chamber. Is characterized in that it is provided.

[0010]

According to the apparatus of the present invention, a horizontal electrode holder chamber made of a corrosion-resistant / insulating material has a rectangular duct-shaped horizontal inside of which a metal strip moves by a gas diffusion electrode plate serving as an insoluble anode. The mold electroplating chamber and the gas chamber on the outside thereof are horizontally partitioned, and the chloride electroplating solution circulates uniformly in the electroplating chamber in the width direction of the metal strip, and the gas chamber contains Hydrogen gas is being blown in. Therefore, chlorine gas or oxygen gas is not generated from the anode, and it is possible to economically produce an electroplated metal strip having high current density, high efficiency, and excellent quality.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the device of the present invention will be described with reference to the drawings. 1 is a schematic plan view showing an embodiment of the apparatus of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG.
5 is a view taken along the line BB of FIG. 4, FIG. 4 is a view taken along the line C-C of FIG. 1, and FIG.
6 is a sectional view taken along the line DD of FIG. 1, and FIG. 6 is a schematic perspective view of a metal strip outlet portion in the apparatus of FIG. As shown in the drawings, a horizontal electrode holder chamber 2 is provided in which a metal strip 1 moves substantially horizontally. The electrode holder chamber 2 includes an upper holder chamber 2a above the metal strip 1 and a lower holder chamber 2b below the metal strip 1, which are made of a corrosion-resistant / insulating material, and are connected to one end of the electrode holder chamber 2. Is a metal strip 1
Of the metal strip 1 is provided at its other end.

In the horizontal type electrode holder chamber 2, the metal strip 1 moving in the chamber 2 is sandwiched between the gas diffusion layer and the reaction layer with a predetermined space above and below the metal strip 1. Gas diffusion electrode plate 4 as an insoluble anode
4 is provided substantially horizontally. Due to such gas diffusion electrode plates 4 and 4, the inside of the electrode holder chamber 2 is
A rectangular duct-shaped horizontal electroplating chamber 5 surrounded by the gas diffusion electrode plates 4 and 4, and an outer side of the gas diffusion electrode plates 4 and 4 located above and below the horizontal electroplating chamber 5. The gas chambers 6 and 6 are horizontally partitioned.

Of the horizontal electroplating chamber 5 in the form of a rectangular duct,
The both ends 5a, 5b of the metal strip moving direction are located in the gas chamber 6,
6, the plating solution supply nozzles 7, 7 for supplying the electroplating solution into the electroplating chamber 5 are provided at the downstream end 5b on the upper surface and the lower surface of the metal strip 1, respectively. Facing away from the gas chambers 6 and 6. The plating solution supply port 8 at the lower ends of the plating solution supply nozzles 7, 7 is formed in a slit shape in the width direction of the metal strip 1.

Discharge ports 9 and 9 for discharging the electroplating solution in the electroplating chamber 5 are provided in the upper and lower portions of the upstream end 5a of the electroplating chamber 5 with the metal strip 1 in between. Of the downstream end 5b of the electroplating chamber 5,
Discharge ports 9 ', 9'for discharging the electroplating solution in the electroplating chamber 5 are provided in the upper and lower portions of the plating solution supply port 8 on the downstream side with the metal strip 1 in between. . The discharge ports 9 and 9 ′ are formed in a slit shape in the width direction of the metal strip 1. The chloride electroplating solution supplied from the plating solution supply nozzles 7 and 7 uniformly flows in the electroplating chamber 5, is discharged from the discharge ports 9 and 9 ', and is returned to the plating tank (not shown) for electroplating. Room 5
Circulate inside.

Each of the gas chambers 6 and 6 is provided with a gas injection port 10 for injecting hydrogen gas into the gas chamber 6 and a gas exhaust port 11 for exhausting the injected hydrogen gas.

A metal for conducting electricity to the metal strip 1 which is close to the inlet opening 3 and the outlet opening 3'of the electroplating chamber 5 and is orthogonal to the moving direction of the metal strip 1 and contacts the upper surface thereof. There is provided a pair of rolls composed of a current-carrying roll 12 and a corrosion-resistant elastic roll 13 made of, for example, hard rubber for contacting the lower surface of the metal strip 1 and pressing the metal strip 1 against the current-carrying roll 12. . Each of the inlet opening 3 and the outlet opening 3'of the electroplating chamber 5 is blocked by the pair of rolls 12 and 13 as described above.

As described above, the pair of rolls includes the current-carrying roll 12 that contacts the upper surface of the metal strip 1 and the elastic roll 13 that contacts the lower surface of the metal strip 1, but the present invention is not limited to this. Not a metal strip 1
Even if the elastic roll 13 that comes into contact with the upper surface of the
Alternatively, even if both are the energizing rolls 12, or,
Both may be elastic rolls 13.

Between the pair of rolls 12, 13 and the electrode holder chamber 2, a seal made of a corrosion-resistant / insulating material is provided so as to cover the surface of the pair of rolls 12, 13 facing the electrode holder chamber 2. Board 14
Are provided in the width direction of the metal strip 1. The gap between the seal plate 14 and the metal strip 1 is about 10 mm or less, which is extremely small. With such a seal plate 14, a current-carrying roll is generated by a plating current leaking from the electroplating chamber 5 or the like.
It is possible to prevent the plating metal from depositing on 12.

The metal strip 1 passes through the inlet opening 3,
A rectangular duct-shaped electroplating chamber 5 in which the chloride electroplating solution is circulated is guided by the energizing roll 12 and the elastic roll 13 on the inlet side and guided to the horizontal electrode holder chamber 2.
Move horizontally continuously. In the meantime, metal strip 1
Electroplating coatings are formed on both surfaces of the metal strip 1 by the gas diffusion electrode plates 4 and 4 as gas insoluble anodes, which are provided above and below the gas diffusion layers and which are composed of a gas diffusion layer and a reaction layer. To be done.

At this time, hydrogen gas is supplied into the gas chambers 6 and 6 outside the gas diffusion electrode plates 4 and 4, and the anodic reaction of the chloride electroplating solution becomes a hydrogen oxidation reaction. Therefore, chlorine gas or oxygen gas is not generated at the anode. In this manner, the metal strip 1 on which the electroplating layer is formed passes through the outlet opening 3 ′, is guided by the outlet-side energizing roll 12 and the elastic roll 13, and is discharged from the electroplating chamber 5.

In the apparatus of the present invention, as described above, the horizontal type electrode holder chamber 2 made of a corrosion-resistant / insulating material is provided inside the rectangular duct-shaped horizontal type electroplating chamber 5 by the gas diffusion electrode plate 4. And the gas chambers 6 and 6 outside thereof are horizontally partitioned, and a necessary minimum amount of electroplating solution is confined in the electroplating chamber 5. Therefore, the amount of the electroplating solution circulating in the electroplating chamber 5 can be small,
Moreover, the structural members of the gas chamber where dangerous hydrogen gas is present, the seals, etc. are not corroded by the plating solution.

The electroplating solution controlled to a predetermined concentration is a plating solution which is provided in the rectangular duct-shaped electroplating chamber 5 at the downstream end thereof and which opens like a slit in the width direction of the metal strip. It is supplied through the supply nozzles 7 and 7, and then discharged through slit-shaped discharge ports 9 and 9 ′ provided at both ends of the electroplating chamber 5 in the width direction of the metal strip. Therefore, the electroplating chamber 5
The flow of the electroplating solution in the inside becomes uniform in the width direction of the metal strip 1, and an electroplating film having excellent quality can be formed on both surfaces of the metal strip 1.

[0023]

As described above, according to the present invention,
Metal strips that move continuously in the horizontal direction can be electroplated industrially by using the gas diffusion electrode as an anode in a horizontal electroplating tank, which produces oxygen gas from the anode. Of high efficiency, high current density, and high quality electroplated metal strips can be produced economically, with industrially useful effects.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an embodiment of the device of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a view taken along the line BB of FIG.

FIG. 4 is a view taken along the line CC of FIG.

5 is a cross-sectional view taken along the line DD of FIG.

6 is a schematic perspective view of a metal strip outlet portion of the apparatus of FIG.

[Explanation of symbols]

 1 metal strip, 2 electrode holder chamber, 3 inlet opening, 3'outlet opening, 4 gas diffusion electrode plate, 5 electroplating chamber, 6 gas chamber, 7 plating solution supply nozzle, 8 plating solution supply port, 9 discharge port, 10 gas inlet, 11 gas outlet, 12 energizing roll, 13 elastic roll, 14 sealing plate.

Claims (1)

[Claims] 1. A horizontal electrode holder chamber having a metal strip inlet opening at one end and a metal strip outlet opening at the other end in which the metal strip moves substantially horizontally. It was provided in the horizontal type electrode holder chamber so that the metal strip moving in the holder chamber is sandwiched and a predetermined space is provided above and below the metal strip to horizontally divide the holder chamber. A gas diffusion electrode plate, a horizontal electroplating chamber partitioned by the gas diffusion electrode plate, formed inside the gas diffusion electrode plate in the holder chamber, in which an electroplating solution circulates, and A gas chamber formed outside the gas diffusion electrode plate in the holder chamber, in which hydrogen gas circulates, and the inlet opening of the horizontal electroplating chamber and the A pair of rolls provided near each of the outlet openings so as to be orthogonal to the moving direction of the metal strip and contacting both upper and lower surfaces of the metal strip; and the pair of rolls and the electrode holder chamber. And a seal plate provided so as to cover the surface of the pair of rolls facing the electrode holder chamber, and at one end side of the electroplating chamber, an electroplating solution in the electroplating chamber is provided. And a plating solution discharge port for discharging the electroplating solution supplied to the electroplating chamber is provided on the other end side of the electroplating chamber. An electroplating device that uses a gas diffusion electrode.