JPH0192399A - Insoluble electrode device - Google Patents

Abstract

PURPOSE:To excellently treat the surface of a metallic strip by making an electrode itself capable of sucking an electrolyte between electrodes, and forming the practically uniform flow of a fresh electrolyte in the space between electrodes. CONSTITUTION:A flow control plate 14 for the electrolyte 2 and a reticular porous electrode plate 13 are provided in this order on the opened surface of a box-shaped body 11 to form an insoluble electrode. The electrode is opposed to the metallic strip 3 so that the distance between the electrode plate 13 and the metallic strip 3 is specified. The electrolyte is supplied from a supply port A, and discharged from an outlet pipe 12a. In addition, plural holes capable of passing the electrolyte are provided to the control plate 14 from one end of the plate surface toward the other end, and the opening degrees of the holes are preferably increased from one end to the other end. By such a constitution, a practically uniform flow of the fresh electrolyte is formed at any part between the electrodes by the action of the control plate 14, and the surface of the metallic strip can be excellently treated.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is applicable to continuous electrolytic treatment on the surface of a metal material such as a metal plate or metal strip without supplying an electrolytic solution into an electrolytic treatment tank. Regarding the insoluble electrode device used for, in more detail, for example, the insoluble electrode device used when continuously applying electroplating, cathodic surface treatment such as electrolytic chromate, or anodic surface treatment such as anodic oxidation to the surface of a metal strip. It is possible to constantly supply a fresh electrolyte throughout the interelectrode space formed between the metal strip to be processed and the insoluble electrode device serving as the counter electrode,
Moreover, the new structure makes it possible to control the flow of the electrolytic solution flowing through the space between the electrodes, thereby reducing unevenness in the flow, and as a result, providing high-quality surface treatment to the metal strip to be treated. The present invention relates to an insoluble electrode device.

(Prior art) When applying a surface treatment such as electroplating to a metal strip, the metal strip is meandered in an electrolytic solution, and an anode is placed opposite the part of the metal strip that is immersed in the electrolytic solution. Then, electrolytic treatment is performed using the metal strip as a cathode.

One example will be explained based on the schematic diagram shown in FIG.

In FIG. 5, 1 is a processing tank filled with a predetermined electrolytic solution 2. Reference numeral 3 denotes a metal strip to be subjected to surface treatment, which is fed into the electrolytic solution from outside the tank and travels through the solution in the direction of arrow P or the opposite direction thereof. 3a and 3b are guide rollers. Reference numeral 4 denotes an anode, which is placed opposite to the part of the metal strip immersed in the electrolytic solution at a predetermined distance.

Various shapes and materials have been proposed for the anode, such as a mesh plate made of an insoluble metal such as titanium, niobium, or tantalum, a perforated plate, or a plain plate with an active material such as platinum or iridium oxide on the surface. Examples include insoluble electrodes coated with substances. One example is shown in FIG. 6 as a perspective view. In the figure, 4a represents a net surface composed of the above-mentioned insoluble metal and active substance. Also,
FIG. 7 is a side view of another example in which a frame 4b is provided around the mesh electrode plate to maintain the shape of the mesh electrode plate as shown in FIG. .

During such electrolytic treatment, efforts are made to continuously supply the electrolytic solution to the processing tank and to continuously discharge it from the processing tank so that the metal strip to be processed is always in contact with fresh electrolytic solution. It is being said. For example, an electrolyte supply section (not shown) is provided at the bottom of the space between the electrodes, and the electrolyte is supplied from there, and a drainage section (also not shown) is provided at the top of the treatment tank to drain the liquid. Various methods have been adopted, including a method in which an electrolyte supply section is provided at the top of the processing tank and a drainage section is provided at the bottom of the processing tank to drain the liquid. In any case, the purpose of these measures is to constantly supply fresh electrolytic solution in a regular flow state with little unevenness over the entire range of the interelectrode space.

(Problem to be Solved by the Invention) By the way, when continuous electrolytic treatment is performed using the apparatus shown in Fig. 5, the electrolyte is supplied from the bottom, drained from the top, and drained from the top as described above. Supply - The electrolyte is supplied to the space between the electrodes by various methods such as draining from the bottom, but since the anode 4 is just one flat plate or a mesh electrode plate, the electrolyte existing in the space between the electrodes is in a stopped state. , a natural convection state, a free flow state caused by the above-described supply-drainage system, or an involuntary free flow state or a turbulent flow state.

For example, even if the electrolyte is supplied from the lower part of the interelectrode section and drained from the upper part, if the amount of fresh electrolyte supplied is small or the pressure at the time of supply is low, the electrolyte will become uniform φ The liquid may not reach the upper drainage area in a fresh state.

Therefore, it cannot be said that the metal strip 3 undergoing surface treatment is in contact with a homogeneous fresh electrolyte over the entire surface to be treated, and therefore, the surface treatment of the metal strip It is difficult to say that progress is being made in a homogeneous manner in terms of processing.

The present invention solves the above-mentioned problems, and makes it possible to form a fresh and uniform flow of electrolyte in the interelectrode space formed between the entire treated surface of the metal strip and the anode. The purpose of the present invention is to provide an insoluble electrode device with a novel structure that enables high-quality surface treatment.

(Means for Solving the Problems) In order to achieve the above object, the inventor has conducted extensive research,
We came up with the idea of making the anode itself have a structure that can attract the electrolyte in the space between the electrodes, confirmed its effectiveness, and developed an electrode device having the structure of the present invention.

That is, in the insoluble electrode device of the present invention, an electrolyte flow adjustment plate and a porous electrode plate are attached in this order to the opening surface of a box-like body that is open on one side and provided with electrolyte outflow holes on the other side. It is characterized by:

The electrode device of the present invention will be explained in more detail based on the exploded perspective view illustrated in FIG.

In the figure, 11 is a box-shaped body made of a liquid-impermeable material, and one side of the box-shaped body is open to form an opening surface 11a. Reference numeral 12 denotes at least one electrolyte outflow hole bored in the box-like body 11, and the hole may be formed in any surface other than the opening surface 11a. The figure shows a state in which one hole is bored in the lower surface of the box-like body 11. An electrolyte outflow pipe 12a is attached to this outflow hole 12 as shown in the figure.

Reference numeral 13 denotes a porous electrode plate, which may be a porous sheet electrode plate in which a large number of through holes of a predetermined shape are distributed within the plate surface, in addition to the mesh electrode plate as illustrated in FIG. In short, any plate-shaped electrode body may be used as long as the electrolyte can pass from one surface to the opposite surface.

Reference numeral 14 denotes a liquid flow regulating plate, which is interposed between the opening surface 11a of the box-shaped body and the porous electrode plate 13.

This liquid flow regulating plate has a plurality of holes formed from one end of the plate surface to the other end. It is a plate that is formed to be larger on the sides. The porosity here refers to the hole area formed in the two halves of the liquid flow control plate when the plate surface is equally divided into two parts from one end to the other end. It is defined as the product of the number and the area of the hole.

FIG. 1 illustrates a case where the hole is a slit groove 14a. The slit grooves 14a are distributed in a sparse manner with a distance between them in the lower plane of the figure, and are distributed in a dense manner with narrower intervals in the upper plane. Furthermore, the slit grooves in the lower plane can be made narrower and the slit grooves in the upper plane wider. Therefore, the open area ratio is large in the upper part of the figure and small in the lower part.

FIG. 2 shows the case of a circular hole 14b in which the holes are distributed within the plate surface. For example, in the lower part of the figure, small diameter holes are sparsely distributed, and in the upper part of the figure, large diameter holes are densely distributed. This is a case where it is distributed. Note that the hole is not limited to a circular hole, for example, a circular hole,
It may have any shape such as various square holes.

Further, the liquid flow regulating plate shown in FIG. 3 has a structure in which a plurality of shutter blades 14d are horizontally suspended between the opening surface 11a of a five-box body and both side frames of a frame body 14c of the same shape. . In this case, the space 14e formed between the shutter blades 14d becomes a hole. This structure adjusts the ltB inclination angle of the shutter blade 14d, that is, for example, the inclination angle of the shutter blade located in the lower part of the figure is increased, and the inclination angle of the shutter blade located in the upper part of the figure is decreased. If this is the case, the aperture ratio of the upper hole in the figure can be set to a large value.

In these liquid flow control plates, the shape, size distribution, pore area, etc. of the holes formed on the plate surface are determined by various conditions in the surface treatment of the material to be treated, such as the condition of the material to be treated. It cannot be determined unambiguously because it needs to be changed depending on dimensions, shape, electrolysis conditions, liquid permeability of the porous electrode plate, etc. More subtly, depending on the attachment position of the electrolyte outflow pipe 12a, the size of the hole and its arrangement can be finely adjusted by, for example, changing the size of the hole and its arrangement on the left and right sides of the plate surface. In short, the size distribution of the holes in the liquid flow control plate can be changed so that the electrolyte flows uniformly through the space between the electrodes.

The electrode device of the present invention is used in the following manner. The state is illustrated in FIG. 4 as a schematic diagram.

In the figure, 1 is a processing tank, 2 is an electrolytic solution filled therein, and 3 is a metal strip running in the direction of arrow P or the opposite direction.

The electrode device of the present invention illustrated in FIG. 1 is arranged so that the running metal strip 3 and the porous electrode plate 13 face each other with a predetermined distance therebetween. In the case of the figure, the liquid flow regulating plate interposed between the box-shaped body 11 and the porous electrode plate 13 is mounted so that the end side where the porosity is small is located downward. and,
Fresh electrolyte is supplied from the lower point A of the interelectrode space, and the electrolyte outflow pipe 12a attached to the bottom surface of the box-shaped body 11 is connected to a suction device such as a drainage pump to discharge the electrolyte from there. do.

In this state, the liquid permeability of the porous electrode plate is approximately concave in its plane, and the liquid flow control plate located behind it has a large porosity above and a small porosity below. In the upper part of the interelectrode space, the electrolyte can easily flow, and in the lower part, it can hardly flow. Therefore, the electrolytic solution supplied from the supply port A does not flow into the box-shaped body so much in the lower part of the device, but flows directly into the upper part, and shifts to a state where it flows more easily. By this,
The supply port A and the electrolyte outflow y12a are located close to each other, which solves the problem that if there was no liquid flow adjustment plate, the supplied electrolyte would take a shortcut and not reach the upper part. . That is, the supply port A and the electrolyte outflow pipe 1
2a are close to each other, the tendency for the electrolyte to easily pass through the short path between them and the tendency for the electrolyte to easily pass above due to the action of the liquid flow regulating plate cancel each other out. After the electrolytic solution reaches the upper part, it is possible to ensure a sufficient amount of the liquid flowing into the box-shaped body. Therefore, a sufficient amount of fresh electrolyte can flow into the interelectrode space from the supply port A at the bottom to the hole that is farthest apart.

Although FIG. 4 shows the case where the supply port A is provided at the bottom, the supply port A may be provided at the top. In this case, the liquid flow regulating plate may be attached to the box-like body of the apparatus in the opposite direction to that shown in the figure, that is, with the side with the smaller pore area facing upward.

In the electrode device of the present invention, the manner in which the liquid flow adjustment plate is attached differs depending on the positional relationship between the electrolyte supply port and the electrolyte drain port, but normally, the liquid flow adjustment plate is mounted on the electrolyte supply port side. Attach the plate so that the side with the smaller porosity is facing.

(Effects of the Invention) As is clear from the above explanation, the electrode device of the present invention allows a liquid flow of electrolyte with little unevenness to any part of the interelectrode space by the action of the liquid flow regulating plate described above. It can be made fresh at all times. Therefore, since fresh electrolyte is supplied to any part of the metal strip running in the tank, the metal strip can be subjected to a higher quality surface treatment than before.

Furthermore, since the electrolytic gas generated on the surface of the porous electrode plate of the device of the present invention is efficiently sucked and removed into the box-shaped body at any point on the plate surface, there is no possibility that these gases will drift into the space between the electrodes. There is no possibility of non-uniform current distribution due to partial heat generation of the liquid or deterioration of the quality of the treated surface caused by these gases reaching the material to be treated.

Although the device of the present invention has been described in connection with continuous electroplating on a metal strip running in a bath, the electrode device of the present invention can be used not only in this case, but also in treatments such as electrolytic chromate and anodic oxidation. Furthermore, even when electroplating a flat metal plate, by using the apparatus of the present invention, it is possible to eliminate the inconvenience that the thickness of the plating layer varies depending on the location and the quality of the plating layer deteriorates. Useful.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing one example of the insoluble electrode device of the present invention. FIGS. 2 and 3 show other examples of liquid flow regulating plates to be attached to the insoluble electrode device 6 of the present invention, respectively. FIG. 4 is a schematic diagram showing how the insoluble electrode device of the present invention is used. FIG. 5 is a schematic diagram showing how a conventional electrode is used, FIG. 6 is a schematic diagram showing one example of the electrode, and FIG. 7 is a side view of another example. 1-Processing tank 2-Electrolyte 3-Metal strip 4-Mesh electrode plate 11-Box-shaped body
12-Electrolyte outflow hole 12a-Electrolyte outflow pipe 1
3-Porous electrode plate 14-Liquid flow adjustment plates 14a, 14b, 14c-holes FIG. 5 FIG. 6 FIG. 7

Claims (1)

[Claims] 1. An electrolytic solution flow adjustment plate and a porous electrode plate are attached in this order to the opening surface of a box-shaped body that is open on one side and provided with an electrolyte outflow hole on the other side. An insoluble electrode device comprising: 2. The liquid flow regulating plate has a plurality of holes through which liquid can pass from one end of the plate surface to the other end, and the aperture ratio of the holes is equal to that of the one end. The insoluble electrode device according to claim 1, wherein the insoluble electrode device increases in size from one end to the other end. 3. The insoluble electrode device according to claim 1 or 2, wherein the liquid flow regulating plate has a slit hole bored in the lateral direction of the plate surface. 4. The insoluble electrode device according to claim 1 or 2, wherein the liquid flow regulating plate has at least one hole selected from the group of circular holes, circular holes, and square holes. 5. The insoluble electrode device according to claim 1 or 2, wherein the liquid flow regulating plate has a shutter structure.