JPH03236495A - Horizontal type electroplating device - Google Patents

Abstract

PURPOSE:To uniformly hold distribution of the flow velocity of plating liquid on a metal strip and to enhance plating quality by spouting plating liquid between this metal strip and an electrode toward the introduction side of the metal strip from a liquid supply nozzle and recovering this spouted plating liquid by a drainage collection pipe provided to the opening part of the introduction side. CONSTITUTION:A strip 1 is horizontally traveled in a plating tank 3 via the energizing rolls 8, 12 and back-up rolls 9, 13. A pair of electrodes 2 are arranged oppositely to both faces of the strip 1. Plating liquid is spouted between the strip 1 and the electrodes 2 toward the introduction side of the strip 1 from the discharge side thereof through the nozzles 5 of liquid supply header 6. The plating drainage is recovered in the receiving tanks 7, 11 for drainage. Thereby the strip 1 is efficiently plated at high current density and high strip passing velocity. In the horizontal type electroplating device, a drainage collection pipe 15 is arranged to the upper part of the strip 1 in the opening part of the introduction side of the plating tank 3. The discharged plating liquid is recovered via a curved face by a scraper 16. Thereby the distribution of flow velocity of plating liquid on the strip 1 is uniformed and further plating deposit is prevented from being stuck to the energizing roll 12 of the upstream side and good-quality plating is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a horizontal electroplating apparatus suitable for plating a metal IF (hereinafter referred to as a strip) at a high current density and at a high strip running speed.

<Prior Art> In the electroplating of strips, many techniques have been disclosed that allow high speed processing at high current densities.

In order to enable high current density processing, it is necessary to: i) how to remove gas, which increases in amount due to high current density, from the strip surface and electrode surface; if) how to increase the critical current density; or The most important point is how to prevent a decrease in plating efficiency caused by insufficient supply of plating metal ions.

It has long been known that so-called counterflow, that is, forcibly circulating the plating solution in the direction opposite to the direction in which the strip travels, is effective as a method of removing gas from the strip surface or electrode surface or increasing the limiting current density. It has been known and practiced since. In other words, in order to improve the limiting current density, it is important to increase the relative velocity between the plating solution and the strip in order to increase the supply of plating metal ions at the strip interface. FIGS. 6 and 7 show an advantageous example of a conventional horizontal electroplating apparatus.
FIG. 3 is a plan view and a side sectional view showing an example.

6 and 7, 1 is a strip, 2 is a 1
Pair of electrodes, 3 fitting tank, 4 side seal, 5 liquid supply nozzle, 6 liquid supply header, 7.11 drainage liquid receiving tank, 8.1
2 is energized roll, 9.13 is backup roll, 10
．． 14 is a drain return pipe.

Plating is carried out by supplying plating solution from the liquid supply header 6 to fill the space between the electrodes 2 and the strips 1 in the form of a flat plate, and allowing the plating solution to flow for 7 nights to obtain a predetermined flow rate of the plating solution. , A direct current is applied between the electrode 2 and the strip 1 by a DC power supply (not shown) connecting the electrode 2 and the current-carrying roll 8.12, and metal ions in the plating solution are deposited on the surface of the strip 1. This is done by

The features of this plating equipment, compared to tray-type plating equipment, are: ■ The plating tank structure is simple and compact; ■ The line tank capacity of the plating tank can be reduced, which means that the amount of circulating fluid is small. One of the advantages of this method is that the plating solution circulation device can be downsized.

<Problems to be Solved by the Invention> In the conventional horizontal electroplating apparatus, the flow rate of the plating solution between the top surface of the strip and the upper electrode is not uniform in the width direction of the strip on the strip entry side of the plating tank. There was a problem.

In addition, problems such as so-called "staining" occur due to local concentration of current density and the alloy composition of the plating metal cannot be maintained.

Furthermore, since a large amount of the discharged plating solution comes into contact with the current-carrying roll, the current flowing through the plating solution causes the plating metal to be plated on the current-carrying roll, causing scratches on the plating surface.

The present invention solves the problems of these conventional techniques and provides a horizontal electroplating system that can maintain a uniform plating solution flow velocity distribution in the width direction of the plating solution outlet side of the upper surface of the strip in the plating tank, thereby improving the plating quality. The purpose is to provide equipment.

<Means for Solving the Problems> According to experiments conducted by the present inventors, as shown in FIG. The results showed that the temperature decreases compared to the ends. As a result of investigating the cause of this, as shown in Figures 6 and 7, plating, 1jJ3
It was found that the cause was that the plating solution flow on the one side of the strip collided with the energizing roll 12 and backup roll 13 in front of it, causing turbulence.

That is, at the ends of the strip 1 in the width direction, the plating liquid after the collision is relatively smoothly discharged outward from the ends in the width direction of the strip, whereas the liquid flow at the center of the strip 1 in the width direction is Since the plating solution flow on the outside (end side) obstructs the discharge, and the plating solution on the top surface of the strip 1 rises upward, back pressure acts on the plating solution flow, and as a result, It was found that this caused a decrease in the plating solution flow rate at the center in the width direction of the plate. Also,
It has also been found that this tendency is more pronounced as the energizing roll 12 approaches the single-person opening of the plating tank 3 on the entry side of the striker 9. Incidentally, it is known that when the plating solution flow rate decreases, the electrolytic gas generated between the electrodes during plating cannot be discharged smoothly, resulting in an increase in voltage and local concentration of current density.

The present invention has been made based on such knowledge. That is, in order to achieve the above object, according to the present invention, a metal plate is placed in a plating tank in which a pair of electrodes are disposed opposite to both sides of a metal band passing through the plate so as to face the passing direction of the metal band. It has a liquid supply nozzle for spouting a plating solution parallel to the metal strip surface from the strip output side toward the input side, and an energized roll and a backup roll are provided on the upstream side of the plating tank and the downstream side of the liquid supply nozzle, respectively. In a horizontal electroplating apparatus having: between an energizing roll and a backup roll on the upstream side of the plating tank and an opening on the metal band entry side of the plating tank,
A horizontal electroplating apparatus, further comprising: a drain collection pipe for collecting the plating solution discharged from the plating tank above the metal band, facing the metal band entrance opening. is provided.

The present invention will be explained in more detail below.

1 and 2 are a partially sectional side view and a partially enlarged view of a horizontal electroplating apparatus showing an embodiment of the present invention.

The strip 1 is electroplated while running from left to right in FIG.

The electrode 2 is provided in a plating tank 3 having a cylindrical cross-section so as to face both the upper and lower surfaces of the running strip 1, and the entire surface facing the strip 1 may be a current-conducting surface, or a portion may be made of an electrically insulating material. An edge mask may be provided to limit the current-carrying surface by sealing with.

The side seal 4 is provided between the upper and lower electrode 2 ends of the strip 1 in the width direction, and forms a plating space with the pair of electrodes 2 to prevent the plating solution from flowing out from both sides of the strip 1 in the width direction. It is set in.

The liquid supply nozzle 5 is for supplying a plating solution from the downstream side of the strip 1 to the upstream side so as to face the direction in which the strip 1 passes, and is located downstream of the pair of electrodes 2 in the direction of passing the strip 1. They are provided in contact with the ends and open toward the top and bottom surfaces of the strip 1, respectively. 6 is a liquid supply header. 8 and 9 are strip support structures each consisting of an energized roll and a backup roll on the downstream side of the plating bath 3. Moreover, 12 and 13 are strip support structures each comprised of an energized roll and a backup roll on the upstream side of the plating tank 3.

A drain liquid receiving tank 7.11 and a drain liquid return pipe 1.14 are provided below the outlet side of the strip 1 and below the inlet side of the plating tank 3.

Between the energizing roll 12 and backup roll 13 on the upstream side of the plating tank 3 and the one-person opening on the entry side of the strip 9 of the plating tank 3, and above the strip 1,
A drain collecting pipe 15 is provided via a scraper 16.

The scraper 16 scoops up the plating solution that is spouted onto the top surface of the strip 1, passes through the plating tank 3, and jets out from the single-person opening on the inlet side of the strip 9, and introduces it into the drain collection pipe 15. The strip 1 is a plate-shaped member having one end close to the upper surface C of the strip 1 over the entire width of the opening of the strip 3. The other end of the scraper 16 is swingably attached to a fulcrum bin 17 provided at one end of the drain collecting pipe 15.

Further, a resin or the like is pasted on a portion of the scraper 16 close to the upper surface of the strip 1 in order to prevent the strip 1 from being damaged even if the strip 1 comes into contact with the scraper 16. In addition, since the scraper 16 is set in a position very close to the top surface of the strip 1, the drain collecting pipe 15 will not be damaged even when the strip 1 has an uneven shape or when the strip 1 swings in the vertical direction. It also serves as a cushioning material.

The drainage collecting pipe 15 is arranged to collect the seeding liquid scooped up by the scraper 16 into the seed part 15.
It has a structure that guides you to a. For example, as shown in FIG. 2, one end having the fulcrum pin 17 forms an arcuate curved surface and is guided to the seed portion 15a at the other end.

As shown in FIG. 3, for example, the bottom surface of the seed portion 15a descends from the center in the widthwise direction of the strip 1 toward both ends, and both ends become tubular discharge portions 15b for draining the introduced matting liquid. It is designed to drop C inside the receiving tank 11.

The drain collecting pipe 15 and the scraper 16 may be made of any material, such as vinyl chloride or FRP, as long as it has chemical resistance to plating solutions, electrical insulation, and sufficient mechanical strength. do not have.

Next, an example of the operation of the horizontal electroplating apparatus of the present invention will be explained.

When the plating solution is forcefully fed and ejected from the liquid supply nozzle 5 in the alternating current direction with respect to the traveling direction of the strip 1 using a pump (not shown), the plating solution flows in the plating tank 3 toward the strip 1 person side and reaches the strip entry side 1 person side. It is discharged from the opening.

On the other hand, the strip 1 is introduced into the plating bath 3 from between the current-carrying roll 12 and the backup roll 13, is plated under predetermined conditions, and then is discharged through the space between the current-carrying roll 8 and the backup roll 9.

Here, the plating liquid on the top side of the strip 1 is removed from the scraper 1.
6, and the seed part 15 of the drain collecting pipe 15
a, and flows down from the discharge part 15b to the drainage tank 11. Therefore, most of the plating solution on the top surface of the strip 1 discharged from the single-person opening on the strip entry side of the plating bath 3 is always discharged in an open state without colliding with the energizing roll 12 and the backup roll 13. Therefore, the plating solution flow velocity distribution in the width direction of the strip 1 can be maintained uniformly.

<Example> The present invention will be specifically explained below based on Examples.

(Example 1) Using the horizontal electroplating apparatus shown in Figs. 1 to 3, Zn-N
Using i plating liquid, thickness 0.7mm% width 2000m
Plating was carried out on a strip of m under the following conditions.

Anode length: total length 1000mm.

Effective length 500 mm Anode width + 1200 mm Anode-strip distance 1i: 15 mm Threading speed: 120 m/min Strip entry side energized roll axis center - Plating tank distance: 300 mm Radius of curvature of arc portion of drain collecting pipe: 200 mm Relative to the scraper strip Inclination angle: 15 degrees Plating detection low strip exit side energized roll center distance +400 mm Plating solution supply amount: 3. 5m' 7min The results are shown in FIG. The solid line in FIG. 4 indicates the flow velocity distribution above the strip on the strip entry side of the plating pot.

(Comparative Example) Using the same strip as in Example 1, plating was carried out using the same apparatus and conditions as in Example 1, except that the drain collecting pipe 15 and scraper 16 were removed.

The results are shown in FIG. 5. The solid line in FIG. 5 shows the flow velocity distribution above the strip on the strip entry side of the plating tank.

By using the plating apparatus of the present invention, most of the plating liquid on the upper surface of the strip was scraped upward by the scraper 16 and led to the drain collection pipe 15. As a result, it was possible to suppress disturbances in the plating solution flow at the single-person side opening of the plating bath 3 on the input side of the striker 9, and to make the flow velocity distribution uniform in the width direction of the strip. That is, it was possible to prevent a decrease in the flow rate of the plating solution in the central portion of the strip 1, and a uniform flow rate between poles was obtained, thereby achieving an improvement in the quality of plating. Furthermore, the amount of liquid that comes into contact with the current-carrying roll can be made very small, and the problem of plating metal adhesion to the current-carrying roll can also be solved.

<Effects of the Invention> Since the present invention is configured as described above, the plating solution flow velocity distribution in the board width direction on the upper surface of the strip can be maintained uniformly, and the plating quality can be improved.

[Brief explanation of drawings]

FIG. 1 is a partially sectional side view of a horizontal electroplating apparatus showing an embodiment of the present invention. FIG. 2 is an enlarged view of portion A in FIG. 1. FIG. 3 is a sectional view taken along line III--III in FIG. 1. FIG. 4 is a graph showing the plating solution flow velocity distribution in the board width direction on the plating solution discharge side of the plating tank. FIG. 5 is a graph showing a conventional plating solution flow rate distribution. 6 and 7 are a side sectional view and a plan view of a conventional horizontal electroplating apparatus. Explanation of symbols 1...Strip, 2...Electrode, 3...Plating tank, 4...Side seal, 5...Liquid supply nozzle, 6...Liquid supply header, 7.11... - Drainage tank, 8.12... Current roll, 9.13... Backup roll, 10.14... Drainage return pipe, 15... Drainage collection pipe, 15a... Bridge section, 15b... Discharge part, 16... Scraper, 17... Fulcrum bin FIG, 1 FIG, 3 FIG, 4 FIG, 5

Claims (1)

[Claims] (1) In a plating bath consisting of a pair of electrodes arranged opposite both sides of the metal strip passing through, the metal strip surface is placed from the metal strip exit side to the input side so as to be opposite to the passing direction of the metal strip. A horizontal electroplating apparatus having a liquid supply nozzle for spouting a plating solution in parallel, and having an energizing roll and a backup roll on the upstream side of the plating tank and the downstream side of the liquid supply nozzle, respectively, the upstream side of the plating tank A drain collection for collecting the plating solution discharged from inside the plating tank is located between the energizing roll and backup roll on the side and the opening on the metal band entrance side of the plating tank and above the metal band. A horizontal electroplating apparatus characterized in that a tube is provided opposite to the metal band entrance opening.