KR102500973B1 - Electrode structure - Google Patents

Abstract

The present invention provides an electrode structure that suppresses deterioration of the electrode structure and furthermore has a long electrode life by mitigating the influence of the temperature rise of the electrode structure itself. A gap C1 through which electrolyte can pass is formed between the electrode plate 2 other than the connection portion 4 and the power supply 3, and the electrode plate 2 is formed on the front and back by allowing the electrolyte to pass through the gap C1. While cooling from both sides, it was made possible to cool the connection part 4 as well.

Description

Electrode structure {ELECTRODE STRUCTURE}

The present invention relates to an electrode structure.

Conventionally, in high-speed electrolytic plating or electrolysis such as high-speed galvanizing, by using an electrode structure formed by segmenting electrode plates and fixing them to a plurality of support plates (power feeders), even if an accident such as contact occurs, it can be solved only by partial repair. making it possible The segments of the electrode plate are connected to the power supply through the connecting portion, but when a large current having a current density of 100 A/dm ² to 300 A/dm ² flows during electrolysis, a relatively large current flows through the connecting portion. In this case, if the electrical resistance of the connecting portion is high, the amount of heat generated may be excessive, which may cause deterioration of the electrode plate and, consequently, the electrode structure.

For example, Patent Literature 1 discloses a technique of arranging a lead plate between an electrode plate and a connection portion between an electrode plate and a power supply. By disposing the lead plate therebetween, the contact between the electrode plate and the power supply becomes more intimate, preventing an increase in electrical resistance and suppressing heat generation.

Patent Document 1: Japanese Unexamined Patent Publication No. 7-331495

However, Patent Document 1 functions very effectively when used in a dry state, but when immersed in a liquid such as sulfuric acid, it generates insulating lead sulfate, or contributes to electrolysis, albeit partially, by energization, leading to lead itself. There was a problem with consumption.

Therefore, an object of the present invention is to suppress the deterioration of the electrode structure by mitigating the influence of the temperature rise of the electrode structure itself, and furthermore to provide an electrode structure with a long electrode life.

In order to achieve the above object, in the present invention, a gap through which electrolyte can pass is formed between an electrode plate other than the connection portion and the power supply, and the electrode plate is cooled from both the front and back sides by passing the electrolyte through the gap. At the same time, it was possible to cool the connection part as well.

That is, the electrode structure disclosed herein includes an electrode plate made of titanium or a titanium alloy as a base material, and a power supply body supporting the electrode plate, and the electrode plate and the power supply body are tightly fixed through a connecting portion. , When immersed in the electrolyte solution, a gap is formed between the electrode plate and the feed body so that the electrolyte solution can pass between the electrode plate other than the connection portion and the feed body, and the electrode plate and It is characterized in that the gap with the feed body is 1 mm or more and 20 mm or less.

The inventors of the present invention, for example, in a high-speed galvanizing line, as shown in FIG. 12, when the temperature of the electrolyte, that is, the electrolytic temperature rises beyond 60 ° C, the electrode life of the electrode plate decreases, and at 70 ° C or more, the electrode life was found to decrease to less than half. During electrolysis, the temperature of the electrode structure may rise mainly due to overvoltage due to electrode reaction on the electrode surface of the electrode plate, and heat generation caused by electrical resistance of the electrode plate, the power supply, and their connection parts. In a high-speed galvanizing line, the temperature of the electrolyte is usually kept constant at about 60°C, but as the heat generation of the electrode structure increases, the temperature of the electrode structure itself becomes higher than about 60°C of the electrolyte, and there is a concern that deterioration of the electrode structure is accelerated. there is.

According to the above configuration, since a gap is formed so that the electrolyte can pass between the electrode plate other than the connection portion and the feeder, when the electrode structure is immersed in the electrolyte, the electrolyte flows in between the electrode plate and the feeder, and the electrode plate and the feeder. A flow of electrolyte occurs in the space between the whole. Then, since the electrode plate itself is cooled on both the front and back surfaces by the electrolyte, the cooling area of the electrode plate can be increased. In addition, by generating a flow of the electrolyte solution in the space between the electrode plate and the power supply, a flow of the electrolyte solution also occurs around the connection portion, and the connection portion with a high calorific value is also cooled. In addition, cooling of the power supply can be accelerated. Therefore, overheating of the electrode plate can be prevented, the temperature of the electrode plate can be lowered to the vicinity of the same temperature as that of the electrolyte solution, and furthermore, the electrode life of the electrode structure can be extended.

Also, the size of the gap is adjusted by the length of the connection part, but as the length of the connection part increases, the electrical resistance of the connection part increases and the amount of heat generated increases. By setting the size of the gap within the above range, the amount of electrolyte flowing between the electrode plate and the power supply can be secured while suppressing the increase in electrical resistance of the connection portion and the amount of heat generated, thereby sufficiently cooling the electrode plate and the connection portion.

In a preferred aspect, the electrode plate is composed of a plurality of segment electrode plates divided into a plurality, and a gap of 1 mm or more and 3 mm or less is formed between adjacent segment electrode plates.

According to this configuration, by forming a gap also between adjacent segment electrode plates, the flow of the electrolyte solution also occurs between the segment electrode plates. Therefore, cooling of the electrode plate or the connecting portion is accelerated, and overheating of the electrode plate is prevented, so that the life of the electrode can be effectively extended.

In a preferred aspect, the electrode plate is composed of a plurality of segment electrode plates divided into a plurality of segments, and the connecting portion includes a convex portion formed on at least one of the segment electrode plate and the feeder, and the electrode at the convex portion. A plate and a mounting member for mounting and fixing the feeding body are provided.

According to this configuration, by dividing the electrode plate into a plurality of parts, maintenance such as repair and replacement of the electrode plate is improved. In addition, by making the connection portion a convex portion, the electrolyte solution flowing between the electrode plate and the power supply can flow around the connection portion, effectively cooling the connection portion.

It is preferable that the said attachment member is a bolt. In this way, the electrode plate and the feeder can be securely fixed in close contact.

In addition, when the electrode plate is energized at a rated current through the power supply, the current density of the connection portion is preferably 0.3 A/mm 2 or more and 1.0 A/mm 2 or less. In this way, it is possible to prevent an excessive amount of heat generated in the connecting portion due to energization while ensuring the amount of current required for electrolysis.

Further, in a preferred embodiment, the shape of the cross section perpendicular to the energization direction of the connection part is such that when the electrode plate is mounted and fixed to the power supply body and immersed in the electrolyte solution, the flow of the electrolyte solution passing through the gap becomes laminar flow It is a shape. Thereby, since turbulence does not occur in the flow of the electrolyte solution around the connection portion, the flow of the electrolyte solution around the connection portion is promoted, so that a high cooling effect can be obtained.

It is preferable that contact surfaces of the electrode plate and the feeder at the connection portion are coated with a platinum group metal. With this configuration, the electrical resistance of the contact surface can be reduced, and the amount of heat generated in the connecting portion can be reduced.

Moreover, in a preferable aspect, the electrode plate and the feeder in the connection portion are joined via a washer. According to this configuration, the strength of the connecting portion can be increased by arranging a metal washer having corrosion resistance between the contact surface of the electrode plate and the feeder.

It is preferable that the washer is made of tantalum coated with platinum on the surface. According to this structure, heat generation of the contact surface of the electrode plate and the washer or the contact surface of the feeder and the washer can be suppressed.

These electrode structures can be suitably used as anodes for electroplating.

As described above, according to the present invention, since the gap is formed so that the electrolyte can pass between the electrode plate other than the connection part and the feeder, when the electrode structure is immersed in the electrolyte, the electrolyte flows in between the electrode plate and the feeder , a flow of electrolyte occurs in the space between the electrode plate and the power supply. Then, since the electrode plate itself is cooled on both the front and back surfaces by the electrolyte, the cooling area of the electrode plate can be increased. In addition, by generating a flow of the electrolyte solution in the space between the electrode plate and the power supply, a flow of the electrolyte solution also occurs around the connection portion, and the connection portion with a high calorific value is also cooled. In addition, cooling of the power supply can be accelerated. Therefore, overheating of the electrode plate can be prevented, the temperature of the electrode plate can be lowered to the vicinity of the same temperature as that of the electrolyte solution, and furthermore, the electrode life of the electrode structure can be extended.

1 is a plan view of an electrode structure according to a first embodiment.
FIG. 2 is a longitudinal cross-sectional view of the electrode structure of FIG. 1 along line II-II.
FIG. 3 is a view of the electrode structure of FIG. 1, as viewed from the back side of the electrode, and is a view schematically showing the flow of electrolyte solution around the connection portion.
4 is a longitudinal cross-sectional view showing a connection portion between a segment electrode plate and a power supply as an example of an electrode structure according to a second embodiment.
Fig. 5 is a diagram corresponding to Fig. 4 of an example of an electrode structure according to the second embodiment.
Fig. 6 is a view corresponding to Fig. 4 of the electrode structure according to the third embodiment.
7 is a plan view of the electrode structure used in the electrode surface temperature measurement test 2.
FIG. 8 is a longitudinal cross-sectional view of the electrode structure of FIG. 7 taken along line VIII-VIII.
9 is a plan view of the electrode structure used in the electrode surface temperature measurement test 3.
Fig. 10 is a longitudinal cross-sectional view taken along line X-X of the electrode structure of Fig. 9;
Fig. 11 is a graph showing the relationship between the distance between the electrode plate and the power supply in the electrode surface temperature measurement test 3 and the electrode surface temperature.
12 is a graph showing the relationship between electrolysis temperature and electrode life.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail based on drawing. The description of the preferred embodiments below is essentially only an example, and is not intended to limit the present invention, its application or its use at all.

(1st Embodiment)

<Electrode structure and its manufacturing method>

As shown in FIGS. 1 and 2 , the electrode structure 1 according to the first embodiment includes an electrode plate 2 and a power supply 3 supporting the electrode plate 2 .

The electrode structure 1 is used as an anode for high-speed electrolytic plating of zinc, chromium, tin, or the like. In addition, the electrode structure 1 is not limited to high-speed electroplating, and can be used as other electrodes for electrolysis, feeding materials such as foil in liquid, and cathodes for surface oxidation treatment.

The electrode plate 2 has a role of advancing the electrolytic reaction on the electrode surface 21A by being supplied with electricity. The electrode plate 2 is constituted by assembling a plurality of segment electrode plates 21 divided into a plurality. The electrode plate 2 may be undivided or divided, but from the viewpoint of maintenance such as repair and replacement, it is divided and a plurality of segment electrode plates are assembled, and is detachably mounted and fixed to the power supply 3 It is preferable to have a configured configuration. The surface area of the electrode surface of the electrode plate 2, the size, shape, thickness, number of sheets, etc. of the segment electrode plate 21 can be appropriately changed depending on the intended use of the electrode structure 1, and is not particularly limited. .

The segment electrode plate 21 includes a substrate and an electrode surface 21A formed by forming an electrode film made of an electrode material on one surface of the substrate. The substrate is made of titanium or a titanium alloy excellent in corrosion resistance even when a strong acid solution is used as the electrolyte. Titanium can use, for example, JIS 1 type or 2 types, and a titanium alloy can use Ti/Pd alloy etc., for example. The electrode material is not particularly limited, but from the viewpoint of promoting the reaction on the electrode surface 21A, for example, Ir/Ta oxide, Pt, Pt/Ir alloy, Pt/Ir oxide, and the like. The method of forming the electrode film is not particularly limited, but it is formed by vapor deposition, plating, thermal decomposition, CVD, or the like.

The power supply 3 is for supporting the electrode plate 2 and supplying electricity to the electrode plate 2 through a power supply cable connected to the rear surface of the power supply 3 . The feeder 3 can be made of a generally used material as appropriate, but at least a portion of its surface that comes into contact with the electrolyte is made of metal that is corrosion resistant to the electrolyte. Examples of the metal include titanium, titanium alloys, zirconium, niobium, and tantalum, and titanium or titanium alloys are preferable. As titanium or a titanium alloy, the thing similar to the base material of the electrode plate 2 can be used concretely. The size, shape, thickness, number of sheets, etc. of the power supply 3 can be appropriately changed according to the purpose of use of the electrode structure 1, and is not particularly limited. For example, a configuration such as a single plate It is also possible to configure the electrode structure 1 by arranging a plurality of feeders 3 having a plurality of segment electrode plates 21 .

The segment electrode plate 21 and the power supply 3 are tightly fixed via the connecting portion 4 .

The connecting portion 4 has a role of passing electricity supplied to the power supply 3 to the segment electrode plate 21, and as shown in FIG. 2, the electrode plate boss portion 41A formed on the segment electrode plate 21. ) (convex portion) and a bolt 43 (mounting member) for attaching and fixing the segment electrode plate 21 and the feeder 3 in the electrode plate boss portion 41A.

A bolt insertion hole 42 for inserting a bolt 43 is formed near the center of the electrode plate boss portion 41A. The segment electrode plate 21 and the feeder 3 are in contact with each other by the electrode plate side contact surface 44 (contact surface) and the feeder side contact surface 45 (contact surface).

The electrode plate side contact surface 44 and the feeder side contact surface 45 (hereinafter sometimes referred to as "contact surfaces 44 and 45") are machined by a grinder from the viewpoint of reducing electrical resistance. At least one of the contact surfaces 44 and 45, more preferably both, is preferably coated with, for example, a platinum group metal such as Pt or Pd. With this configuration, the electrical resistance of the contact surfaces 44 and 45 can be reduced. Therefore, it is possible to reduce the amount of heat generated by the connecting portion 4 during power supply. And the electrode back surface 21B of the segment electrode plate 21 and the feeding body surface 3A of the feeding body 3 may be machined or may not be machined.

A bolt hole 46 is drilled near the center of the feeder-side contact surface 45, that is, at a position corresponding to the bolt insertion hole 42 when the contact surfaces 44 and 45 are in contact with each other.

The segment electrode plate 21 is mounted and fixed to the bolt hole 46 of the feeder 3 by the bolt 43 inserted through the bolt insertion hole 42 . At this time, the plurality of segment electrode plates 21 are mounted on the feeder 3 so that the above-described electrode surfaces 21A have the same height with respect to the feeder 3 .

The method of attaching and fixing the segment electrode plate 21 to the feeder 3 is not particularly limited, and any general method can be employed, but to firmly fix the segment electrode plate 21 and the feeder 3 in close contact From this point of view, bolted fastening is preferred. In this specification, “bolt fastening” means, as shown in FIG. 2 , in addition to the structure fixed to the feeder 3 by the bolt 43 on the electrode surface 21A side, to the bolt on the feeder 3 side. It also includes a configuration fixed to the segment electrode plate 21 by the. Further, for example, a stud bolt may be disposed on the segment electrode plate 21 or the power supply 3 and fixed to the power supply 3 or the segment electrode plate 21. These are collectively referred to as "bolt fastening".

The material of the bolt 43 is made of a metal that is corrosion resistant to the electrolyte solution, and is preferably made of titanium or a titanium alloy. As titanium or titanium alloy, specifically, the same thing as the base material of the electrode plate 2 can be used.

From the viewpoint of suppressing the amount of heat generated from the connecting portion 4 and accelerating cooling by the electrolyte, the connecting portion 4 is preferably thin, while thick is preferable from the viewpoint of current density. The diameter of the connecting portion 4 varies depending on the value of the applied current, but when energized at a rated current (current density of about 100 A/dm ² to about 500 A/dm ² ), for example, sufficient for the segment electrode plate 21 From the viewpoint of suppressing the amount of heat generated in the connecting portion 4 while ensuring the power supply amount, the current density of the connecting portion 4 is preferably 0.3 A/mm2 or more and 1.0 A/mm2 or less, more preferably 0.55 A/mm2 or more and 0.75 A. /mm2 or less is the diameter.

Here, the electrode structure 1 according to the present embodiment is characterized in that a gap C1 is formed between the segment electrode plate 21 and the feeder 3. By the presence of the gap C1, when the electrode structure 1 is immersed in the electrolyte, the electrolyte can pass between the segment electrode plate 21 other than the connection portion 4 and the power supply 3, FIG. 2 And as indicated by arrows in FIG. 3 , a flow of the electrolyte solution occurs between the segment electrode plate 21 and the power supply 3 and around the connection portion 4 . Then, since the segment electrode plate 21 itself is cooled on both the front and back sides by the electrolyte solution, the cooling area of the segment electrode plate 21 can be increased. In addition, the flow of the electrolyte around the connecting portion 4 also cools the connecting portion 4 having a large calorific value. Therefore, overheating of the segment electrode plate 21 can be prevented, and the electrode surface temperature of the segment electrode plate 21 and thus the entire electrode plate 2 can be lowered to the same temperature as that of the electrolyte solution, and the electrode structure 1 electrode life can be extended. However, in the conventional electrode structure described in Patent Literature 1, for example, a gap is not formed between the electrode plate and the feeder other than the connection portion between the electrode plate and the feeder from the viewpoint of preventing penetration of the electrolyte solution, Or, even if it is formed, only a very small gap of about 0.5 mm or less is formed. The very small gap is to prevent the electrode from being damaged due to a short circuit, etc. caused by impurities in the electrolyte being caught between the electrode plate and the power supply. Intrusion of a certain amount of liquid does not occur.

The gap C1 between the segment electrode plate 21 and the feeder 3 is preferably 1 mm or more and 20 mm or less. If the gap C1 is less than 1 mm, it becomes difficult for the electrolyte to flow smoothly, and there is a possibility that the cooling effect may be reduced. In addition, when the gap C1 exceeds 20 mm, the electrical resistance of the connecting portion 4 increases as the length of the connecting portion 4 increases, and there is a possibility that the amount of heat generated from the connecting portion 4 increases excessively. In addition, from the viewpoint of miniaturization of devices such as an electrolytic cell in which the electrode structure 1 is installed, the size of the gap C1 is more preferably 3 mm or more and 10 mm or less.

Adjacent segment electrode plates 21 may be disposed so as to contact each other, but, for example, as described in FIGS. 1 and 2, along with the gap C1 between the segment electrode plate 21 and the power supply 3 , It is good also as a structure which forms the space|interval C2 also between the adjacent segment electrode plates 21. By forming the gap C2, a flow of the electrolyte also occurs between the segment electrode plates 21 as indicated by arrows in FIG. 2 . Therefore, cooling of the electrode plate 2 or the connecting portion 4 is accelerated, and overheating of the electrode plate 2 is prevented, so that the life of the electrode can be effectively extended. The size of the gap C2 can be preferably 1 mm or more and 3 mm or less. As shown in Fig. 1, the interval C2 is divided into a first interval C21 and a second interval C22. Among the intervals C2, at least one of the first interval C21 and the second interval C22 is preferably formed. For example, when the electrode structure 1 is used as an anode for plating of a metal plate material, an interval C2 of 1 mm or more and 3 mm or less is formed between the flow direction and the vertical direction of the metal plate material to be plated, so that the electrolyte is It spreads, and the cooling effect is magnified. In addition, although a gap may be formed in the direction parallel to the flow direction of the metal plate material to be plated, since there is a concern that the coating thickness of the plated steel sheet may become non-uniform, it is preferable to form the gap C2 in consideration of the arrangement between the electrode plates. .

And, the shape of the connection part 4 is not particularly limited, but since the heat generation of the connection part 4 is large and cooling of the connection part 4 is more important, a sufficient amount of electrolyte is supplied around the connection part 4, and It is important to flow as fast as possible. Therefore, it is preferable that the electrolyte solution flow around the connection part 4 is laminar flow, and for this purpose, it is preferable that the corner part or deformation part of the connection part 4 be minimized. That is, as shown in Fig. 3, it is preferable that the shape of the cross-section perpendicular to the energization direction of the connecting portion 4 is circular or elliptical without corners, that is, the connecting portion 4 is preferably cylindrical or elliptical. do. Thereby, turbulent flow does not occur in the flow of the electrolyte around the connecting portion 4, but it becomes a laminar flow, and the flow of the electrolyte around the connecting portion 4 is promoted, so that a high cooling effect can be obtained.

And, the electrode surface temperature of the electrode structure 1, from the viewpoint of extending the life of the electrode, the difference from the temperature of the electrolyte solution is preferably less than 6 ° C, more preferably within 5.5 ° C, particularly preferably within 5 ° C It is preferable that the temperature is

<Electrolysis tank and electrolysis conditions>

When using the electrode structure 1 as an anode for plating, the electrode structure 1 is used as an anode and a material to be plated (not shown) as a cathode, and is placed in an electrolytic cell (not shown). The material to be plated is, for example, a coil, plate, or wire of a conductive metal such as iron, steel sheet, copper, or nickel. The distance between the anode and the cathode may be appropriately changed depending on plating conditions, but may be, for example, 10 mm to 50 mm. Further, an energizing cable (not shown) is mounted on the back surface 3B of the feeder. Conditions such as the type, concentration, and liquid amount of the electrolyte may use conditions of a generally used electrolyte solution, but may be appropriately changed according to the purpose of use of the electrode structure 1. In addition, the temperature of the electrolyte solution can be maintained at a desired temperature by circulating the electrolyte solution between the electrolytic cell and a heater installed outside the electrolytic cell, for example, in the case of high-speed galvanizing, it can be maintained at about 60°C. The electrolytic conditions may be appropriately changed depending on the intended use of the electrode structure 1, but, for example, the electrolytic conditions for high-speed galvanizing may be a current density of 100 A/dm ² to 500 A/dm ² .

<electrode life>

When the electrode structure 1 according to the present embodiment is used as an anode for electrolytic plating, the life of the electrode is 1.5 times or more, more preferably, compared to the case where the electrode structure 1 without forming the gap C1 is used. It can be extended more than twice.

(Second Embodiment)

Hereinafter, other embodiments according to the present invention will be described in detail. Incidentally, in the description of these embodiments, the same reference numerals are assigned to the same parts as those in the first embodiment, and detailed descriptions are omitted.

In the first embodiment, as shown in FIG. 2, the electrode plate boss portion 41A is formed on the segment electrode plate 21 side, but as shown in FIG. 4, the power supply is on the power supply 3 side. It is good also as a structure which forms the boss part 41B. Further, as shown in Fig. 5, an electrode plate boss 41A and a feeder boss 41B may be formed on both the segment electrode plate 21 and the feeder 3, respectively. In either configuration of FIGS. 4 and 5 , the segment electrode plate 21 and the feeder 3 contact each other at contact surfaces 44 and 45 .

(Third Embodiment)

In the first and second embodiments, the segment electrode plate 21 and the feeder 3 are in contact with each other at the contact surfaces 44 and 45, but from the viewpoint of increasing the strength of the connection portion 4, FIG. As shown, a washer 48 may be interposed between the electrode plate-side contact surface 44 and the feeder-side contact surface 45 so as to bond them together. In this case, since the contact surfaces 44 and 45 are in contact with the surface of the washer 48, the contact surface increases, so that the surface slightly deforms during bolt fastening, for example, tantalum and It is preferable to use a metal washer 48 having the same flexibility and corrosion resistance. Specifically, for the washer 48, a platinum group metal such as Ta, a Ta/Nb alloy, platinum, palladium, or gold can be used. On the surface of the washer 48, it is preferable to perform an energization holding treatment such as forming a platinum film, for example.

Example

Next, concretely implemented examples will be described.

(electrode surface temperature measurement test 1)

<Example 1>

As the electrode plate 2, a titanium plate having a length of 200 mm x a width of 200 mm and a thickness of 15 mm was coated with an electrode made of Ir/Ta oxide to a thickness of about 20 µm on one side, and the surface of the electrode was used. Further, as the feeder 3, a titanium plate having a length of 200 mm, a width of 200 mm, and a thickness of 30 mm was used. As the connection portion 4, a feeder boss having a diameter of 55 mm and a height of 3 mm is formed at the center of the feeder 3, and a bolt hole for fastening the M12 bolt is formed at the center, and a surface other than the bolt hole is formed. It was machined, flattened, and platinum plated with a thickness of 0.1 μm to obtain a contact surface on the feeder side. In addition, the electrode back surface of the electrode plate 2 was machined and smoothed. Then, a through-hole for inserting a bolt for attaching a feeder was formed in the central portion of the electrode plate 2 . The electrode plate 2 was mounted and fixed to the feeding body boss of the feeding body 3 by means of M12 titanium bolts inserted into the bolt insertion holes. Here, the distance between the electrode plate 2 and the power supply 3 is 3 mm.

Then, a PR thermocouple was welded to the vicinity of the bolt position on the electrode surface of the electrode plate 2, and the welded portion was sealed with an epoxy resin.

The electrode structure 1 prepared in this way is used as an anode and an upper electrode, and a zirconium plate of 200 mm in length × 200 mm in width is used as a cathode and a lower electrode, and is placed in parallel with each other with a gap of 20 mm. 3) was installed in the electrolytic cell so that the upper part came out 10 mm. Then, an energizing cable is attached to the back surface of the feeder 3. A 150 g/L aqueous solution of sulfuric acid was used as the electrolyte solution, and the temperature of the electrolyte solution was 60°C. Here, the amount of electrolyte solution was 50 L. The liquid was circulated between the heater parts to maintain the temperature at 60 °C. Then, electrolysis was performed at a current amount of 1000 A (current density: 250 A/dm ² ), and the electrode surface temperature was measured. In addition, the current density of the connecting portion was equivalent to 0.42 A/mm 2 . At 20 minutes of electrolysis time, the electrode surface temperature became substantially constant, and the electrode surface temperature at that time was taken as a measured value.

<Comparative Example 1>

Measurement was performed in the same manner as in Example 1, except that the electrode fixing portion of the feeder was flat, and the front surface of the feeder electrode fixing portion was machined together with the back surface of the electrode to prepare an electrode structure fixed with M12 bolts in the same way.

＜Results and considerations＞

In both Example 1 and Comparative Example 1, the electrolyte temperature was 60°C.

And in Example 1, the measured value of the electrode surface temperature was 62 degreeC, and it turned out that it is a temperature substantially the same as the electrolyte solution temperature.

On the other hand, in Comparative Example 1, the measured value of the electrode surface temperature was 66°C, and it was found to be 6°C higher than the temperature of the electrolyte solution. In the configuration of Comparative Example 1, since the flow of the electrolyte solution on the back side of the electrode and around the connection part is suppressed, cooling is not performed on the back side of the electrode plate, and cooling is performed only on the side of the electrode surface exposed to the electrolyte solution. Therefore, the cooling of the electrode plate is insufficient. It is thought to be

(electrode surface temperature measurement test 2)

<Comparative Example 2>

As shown in Figs. 7 and 8, as the segment electrode plate 21, a titanium plate having a length of 100 mm × a width of 100 mm and a thickness of 15 mm is coated with an electrode made of Ir/Ta oxide and having a thickness of about 20 µm. Four sheets were prepared in which the electrode surface 21A was formed. Since the connecting portion 4 is formed at the center of the back surface of the electrode of the segment electrode plate, an electrode plate boss having a diameter of 25 mm and a height of 2 mm is formed, and a bolt insertion hole for fastening the M10 titanium bolt is formed at the center of the electrode plate boss. did Surfaces other than the bolt insertion hole of the electrode plate boss portion were machined and smoothed to obtain an electrode plate side contact surface.

On the other hand, as the feeder 3, a titanium plate having a length of 210 mm, a width of 210 mm, and a thickness of 30 mm was used. In order to form the connecting portion 4, four feeder bosses having a diameter of 26 mm and a height of 2 mm were formed on one side of the titanium plate in accordance with the position where the electrode plate bosses are disposed. A bolt hole having a diameter of 12 mm was formed in the center of the feeder boss portion, and surfaces other than the bolt hole were smoothed by machining to obtain a feeder side contact surface.

As shown in FIGS. 7 and 8 , the electrode structure 1 was obtained by mounting and fixing the above-mentioned four segment electrode plates with M10 bolts 43. At this time, the four mounted segment electrode plates 21 were parallel to each other, and the interval between the adjacent segment electrode plates 21 was set to 2 mm. And, the distance between the segment electrode plate 21 and the feeder 3 is 4 mm.

Next, a PTFE plate (not shown) capable of filling the gap C1 between the electrode plate and the feeder was prepared by placing it between the four segment electrode plates 21 and the feeder 3. In addition, a PTFE plate (not shown) capable of filling the gap C2 between adjacent segment electrode plates 21 was prepared.

Regarding the electrode structure (1), both the gap (C1) and the gap (C2) were filled to form an anode, and it was fixed in the same electrolytic cell as in Example 1. The cathode was placed at the bottom of the electrolytic cell using a zirconium plate in the same way. The distance between the electrodes was set to 20 mm, the electrode structure (1) was installed on the upper side, and the cathode zirconium was installed in parallel with the electrode structure (1). One of the four segment electrode plates 21, a PR thermocouple was attached to a portion close to the center of the electrode plate 2, and the electrode surface temperature was measured.

The electrolyte was 150 g/L sulfuric acid + 50 g/L sodium sulfate (Na ₂ SO ₄ ) aqueous solution, and the temperature was 60°C. Electrolysis was performed by passing a current of 300 A (a current density of 300 A/dm ² ) through each electrode plate. The current density of the connecting portion was equivalent to 0.61 A/mm 2 . The electrolysis time was 20 minutes, and the temperature of the surface of the electrode plate was measured.

<Example 2>

Measurement was performed in the same manner as in Comparative Example 2, except that the PTFE plate filling the gap C1 between the segment electrode plate 21 and the power supply 3 was removed.

<Example 3>

The measurement was performed in the same manner as in Comparative Example 2 except that the PTFE plate filling the gap C1 and the PTFE plate filling the gap C2 between the adjacent segment electrode plates 21 were removed.

＜Results and considerations＞

The results of Comparative Example 2 and Examples 2 and 3 are shown in Table 1.

[Table 1]

In Comparative Example 2, it is considered that the temperature rose significantly because cooling was not performed on the back side of the segment electrode plate.

In Example 2, by removing the PTFE plate filling the gap C1 between the segment electrode plate and the power supply, the electrolyte solution flows to the back side of the segment electrode plate 21, serving as a cooling liquid, and the electrode surface temperature is reduced by the electrolyte solution. It is thought that the temperature was lowered to the vicinity.

Further, in Example 3, the electrode surface temperature was further reduced by further removing the PTFE plate filling the gap C2 between the segment electrode plates 21 in the state of Example 2. This is considered to be because the liquid circulation is further improved by generating a liquid flow through between the segment electrode plates, and the cooling effect by the flow of the electrolyte solution is improved.

(electrode surface temperature measurement test 3)

<Examples 4 to 7, Comparative Example 3>

Using the electrode structure 1 shown in FIGS. 9 and 10 , electrolysis was performed under the same conditions as in Comparative Example 2, and the change in electrode surface temperature according to the distance between the electrode plate and the power supply was investigated.

And, the configuration of the electrode structure 1 shown in FIGS. 9 and 10 is the same as the configuration of Comparative Example 2 shown in FIGS. 7 and 8 except for the following points.

That is, as shown in Figs. 9 and 10, PTFE sealing 6 is performed along the outer circumference of the segment electrode plate 21 and the feeder 3, and the gap between the segment electrode plates 21 is prevented from entering and exiting the electrolyte. (C2) only. In this way, even if the distance between the electrode plate and the power supply changes, the flow rate of the electrolyte solution flowing into the gap C1 is kept constant.

In addition, both the electrode plate side contact surface 44 of the segment electrode plate 21 constituting the connection portion 4 and the feeder side contact surface 45 of the feeder 3 have a thickness of 0.1 μm from the viewpoint of reducing electrical resistance. Platinum plating was performed. Then, between the contact surfaces 44 and 45, a washer 48 made of tantalum coated with platinum was disposed. The distance between the electrode plate and the power supply was adjusted by adjusting the thickness of the washer 48 in the range of 5 mm to 25 mm.

Table 2 and FIG. 11 show the results of measuring the electrode surface temperature rise according to the change in the distance between the electrode plate and the power supply of the electrode structure 1 of Examples 4 to 7 and Comparative Example 3.

[Table 2]

It was found that the electrode surface temperature gradually increased as the distance between the electrode plate and the feeder increased from 5 mm to 25 mm. This is considered to be caused by the fact that the liquid flow velocity around the connecting portion 4 decreases as the distance between the electrode plate and the power supply increases, and the amount of heat generated by the connecting portion 4 increases.

(electrode life verification test)

<Example 8 and Comparative Example 4>

In order to confirm that the life of the electrode is extended as cooling is performed on the back side of the electrode plate 2, an operation test was conducted in an actual continuous high-speed galvanizing line.

That is, the electrode structure 1 of Example 8 was prepared as follows. As the segment electrode plate 21, a titanium plate having a length of 200 mm × a width of 200 mm and a thickness of 20 mm was coated with an electrode made of Ir/Ta oxide to a thickness of about 20 μm to form an electrode surface. A part of the back side of the electrode of the segment electrode plate 21 is machined to form two circumferential electrode plate bosses with a height of 4 mm, and with a distance of 3 mm between the segment electrode plates on the smooth feeder, each is tightened with two bolts. Bolt tightened.

As the electrode structure of Comparative Example 4, the back surface of the electrode of the segment electrode plate was smoothed and bolted directly to the smooth feeder was used.

The electrolyte was a high-speed galvanizing bath (ZnSO ₄ , 200 g/L), and the temperature of the electrolyte was 60±2°C. A steel sheet was used as the material to be plated. The electrolysis current density was 120 A/dm ² , and continuous electrolysis was performed by attaching it as an electrode in a plating line.

＜Results and considerations＞

The electrode structure having no gap between the segment electrode plate and the power supply of Comparative Example 4 expired in 3 months. On the other hand, it was found that in Example 8 having a gap of 4 mm between the feeder and the electrode plate, the initial performance was maintained even after 9 months or more.

INDUSTRIAL APPLICABILITY The present invention is very useful because it can suppress the deterioration of the electrode structure by mitigating the influence of the temperature rise of the electrode structure itself and, consequently, provide an electrode structure with a long electrode life.

1: electrode structure 2: electrode plate
21: segment electrode plate 21A: electrode surface
21B: Electrode Back 3: Feeder
3A: Feeder surface 3B: Feeder back surface
4: connection part
41A: electrode plate boss (convex shape)
41B: Feed body boss (convex shape)
42: bolt insertion hole 43: bolt (mounting member)
44: electrode plate side contact surface (contact surface) 45: feeder side contact surface (contact surface)
46: bolt hole 48: washer
C1: gap C2: gap
C21: 1st interval C22: 2nd interval

Claims (10)

An electrode plate based on titanium or titanium alloy;
A feeder supporting the electrode plate
to provide,
The electrode plate is made of a plurality of segment electrode plates divided into a plurality,
The electrode plate and the power supply are tightly fixed through a connecting portion,
When immersed in the electrolyte solution, a gap is formed between the electrode plate and the feed body so that the electrolyte solution can pass between the electrode plate other than the connection portion and the feed body,
The gap between the electrode plate and the power supply is 1 mm or more and 20 mm or less,
An electrode structure, characterized in that a gap of 1 mm or more and 3 mm or less is formed between the adjacent segment electrode plates. The method of claim 1,
The connection part,
A convex portion formed on at least one of the segment electrode plate and the feeder;
Electrode structure characterized by comprising a mounting member for mounting and fixing the electrode plate and the feeder in the convex shape. The method of claim 2,
The electrode structure, characterized in that the mounting member is a bolt. According to claim 1 or claim 2,
When the electrode plate is energized at a rated current through the feeder, the electrode structure characterized in that the current density of the connection portion is 0.3 A / mm or more and 1.0 A / mm or less. According to claim 1 or claim 2,
The shape of the cross section perpendicular to the energization direction of the connection part is a shape in which the flow of the electrolyte solution passing through the gap becomes laminar flow when the electrode plate is immersed in the electrolyte solution in a state where the electrode plate is mounted and fixed to the power supply body. struct. According to claim 1 or claim 2,
The electrode structure characterized in that the contact surface of the electrode plate and the feeder in the connection portion is coated with a platinum group metal. According to claim 1 or claim 2,
The electrode structure characterized in that the electrode plate and the feeder in the connection portion are bonded through a washer. The method of claim 7,
Electrode structure, characterized in that the washer is made of tantalum coated with platinum on the surface. According to claim 1 or claim 2,
Electrode structure characterized in that the anode for electrolytic plating.
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