KR20170005477A - Basket type anode - Google Patents

Abstract

The basket-type anode is used for electrolytic plating of a steel strip, containing plating material particles in a plating bath. A basket-shaped anode, and a network member made of Ti disposed opposite to the steel strip, wherein the network member contains a platinum group element. If the mesh member contains a platinum group element, corrosion of the mesh member can be prevented, and the service life of the mesh member can be improved.

Description

[0001] BASKET TYPE ANODE [0002]

The present invention relates to a basket-type anode used for electrolytic plating of a steel strip.

In the electrolytic plating in which the surface of the steel strip is continuously plated, a box-shaped basket-type anode is widely used. In the basket-type anode, the front face opposing the steel strip in the plating bath is constituted by a mesh member (lath), and accommodates the plating raw material particles. During the electrolytic plating, the plating raw material particles in the basket-shaped anode are electrolyzed and ionized by energization to the body portion of the basket-like anode, and the metal ions are guided to the surface of the steel strip to form plating. The body portion and the mesh member of the basket-like anode are made of pure Ti (pure titanium) in view of the requirement of corrosion resistance.

In recent years, there has been a demand to perform plating on a large steel strip or to perform plating with a thick film thickness. In the electrolytic plating operation corresponding to this demand, it is necessary to supply a large current to the anode body portion. However, due to the supply of a large current to the anode main body, the mesh member may be corroded and damaged. For example, when the plating raw material particles are Ni particles and the plating bath is electrolytic Ni plating, which is a watt bath, part of the mesh member is corroded with the progress of operation, and a hole is made in the mesh member.

When the breakage of the mesh member becomes significant, the possibility of the plating raw material particles leaking from the basket-type anode is increased. For example, when the plating raw material particles leak, the capacity of the plating raw material particles in the basket-shaped anode sharply drops, and the amount of metal ions in the plating bath fluctuates. Further, the plating material particles leaked into the plating bath may be passed through the roller for conveying the steel strip. This situation causes deterioration of the quality of the coated steel sheet.

The prior art for coping with this problem is as follows. Japanese Patent Application Laid-Open No. 4-37907 (Patent Literature 1) and Japanese Patent Laid-Open Publication No. 2011-89148 (Patent Literature 2) disclose a technique of inspecting a reticular member against an anode main body portion, There is disclosed a technique for suppressing corrosion and accompanying breakage of the mesh member.

Specifically, Patent Document 1 discloses a basket-type anode in which an installation structure of a mesh member to an anode body portion is improved. In the basket-type anode described in this document, the mesh member is provided on the anode main body through the insulating material.

Patent Document 2 discloses a basket-type anode in which the structure of the network member itself is improved. In the basket-type anode described in this document, an Al ₂ O ₃ (alumina) insulating coating is formed on the surface of the mesh member, and the insulating coating is sealed with a coating of PTFE (polytetrafluoroethylene).

However, even when the above-described conventional technique is applied, the actual state does not sufficiently suppress damage caused by corrosion of the mesh member. In this case, in order to prevent deterioration of the quality of the coated steel sheet, the reticulated member must be frequently replaced, so that the productivity of the coated steel sheet can not be avoided. From these facts, it is strongly desired to improve the service life of the mesh member.

Japanese Utility Model Publication No. 4-37907 Japanese Patent Application Laid-Open No. 2011-89148

An object of the present invention is to provide a basket-type anode having the following characteristics:

To improve the life of the mesh member.

A basket-type anode according to an embodiment of the present invention is a basket-type anode used for electrolytic plating of a steel strip containing plating material particles in a plating bath,

The basket-shaped anode has a mesh-like member made of Ti arranged opposite to the steel strip, and the mesh-shaped member contains a platinum group element.

In the above-described anode, the content of the platinum group element is preferably 0.01% to 0.15% by mass.

In the above-described anode, the network member may further comprise at least one of Ni and rare earth elements. In this case, the Ni content is preferably 0.2% to 1.0% by mass%, and the content of the rare earth element is preferably 0.0005% to 0.020% by mass%. In the above-described anode, as the impurity element, Fe: not more than 0.3%, O: not more than 0.35%, C: not more than 0.18%, H: not more than 0.015%, N: not more than 0.03% At most 0.2% of Cr, at most 0.2% of Zr, at most 0.2% of Nb, at most 0.02% of Si, at most 0.2% of Sn, at most 0.01% of Mn, at most 0.35% of Co and at most 0.1% The total content may be 0.6% or less.

The above-described anode can be used for electrolytic plating in which the plating material particles are Ni particles. In addition, the above-described anode can be used for electrolytic plating in which the plating bath is a watt bath.

The basket-type anode of the present invention has the following remarkable effects:

Capable of improving the life of the mesh member.

1 is a front view of a basket-type anode.
2 is a longitudinal sectional view of the basket-type anode along the vertical direction.
3 is a schematic view of a test apparatus used for a basic test of corrosion resistance investigation.

The inventors of the present invention have investigated the cause and the remedy for the occurrence of breakage of the mesh member made of pure titanium by the operation of electrolytic plating for supplying a large current to the main body of the basket-shaped anode. The examination was conducted by taking electrolytic Ni plating, which is a representative of electrolytic plating, as an example. In the case of electrolytic Ni plating, the plating raw material particles are Ni particles, and a watt bath is employed as the plating bath.

[Standard configuration of basket type anode]

1 is a front view of a basket-type anode. 2 is a longitudinal sectional view of the basket-type anode along the vertical direction. The arrows on the white background in FIG. 2 indicate the flow of current supplied to the main body of the basket-shaped anode.

The basket-type anode 1 is immersed in a plating bath 11 and used to accommodate the plating material particles 10 in the plating bath 11 and to perform electrolytic plating on the steel strip 12. [ The basket-shaped anode 1 is box-shaped with an opened top face, and has an anode main body 2 and a mesh member 3 constituting a front face. The mesh member (3) is disposed opposite to the steel strip (12) in the plating bath (11). The inner space of the basket-type anode (1) is filled with the plating material particles (10).

The anode main body portion 2 includes a back plate 2a, side plates 2b and 2c which are pair of left and right sides, and a bottom plate 2d. A bus bar 2e for supplying a current to the anode main body 2 is provided on the upper surface of the back plate 2a. The mesh member 3 is provided on the front surface side of the anode main body 2 having such a configuration. Specifically, a plurality of pillars 4 are projected from the back plate 2a toward the front. The mesh member 3 is struck by the front end of each strut 4 and the retaining plate 5 is placed in the position of each strut 4 on the mesh member 3. The pressure plate (5) is fastened to each strut (4) by bolts (6). The mesh member 3 is retained in the front face side of the anode main body 2 in a state sandwiched between the struts 4 and the press plate 5. [

The mesh member 3 is constituted by stacking two nettings 3a and 3b precisely. The front side of bag 7 made of cloth is sandwiched between the nettings 3a and 3b. The bag 7 transmits metal ions of the plating raw material particles 10 that are electrolytically plated while preventing electrolytic plating material particles 10 from leaking from the mesh of the mesh member 3 do. The techniques described in the above Patent Document 2 may be applied to the metal meshes 3a and 3b here. That is, the metal meshes 3a and 3b may have an insulating film of Al ₂ O ₃ formed on its surface, and the insulating film may be sealed with a coating of PTFE.

In addition, the mesh member 3 is provided on the anode main body portion 2, which is generally divided into a plurality of stages in the vertical direction. In the basket-type anode 1 shown in Fig. 1, the mesh member 3 is divided into four stages.

During electrolytic plating, current is supplied to the main body portion 2 of the basket-like anode 1 through the bus bar 2e of the back plate 2a. By this energization, the plating raw material particles 10 in the basket-like anode 1 are electrolyzed and ionized, and the metal ions are guided to the surface of the steel strip 12 to form plating.

[Outline of Causes of Damage due to Corrosion of Mesh Members and Countermeasures Against Corrosion]

In the conventional basket-type anode, the material of the mesh member includes the case of adopting the technique described in the above-mentioned Patent Document 2, and it was pure Ti. The occurrence of breakage (hole piercing) of the mesh member in the operation of electrolytic Ni plating for supplying a large current to the anode main body portion was investigated using this conventional basket-type anode. As a result, the following findings were obtained.

The breakage of the mesh member is liable to occur at the upper portion of the mesh member. This is believed to be due to the fact that the pH of the plating bath is lowered, in particular at the top of the mesh member, as described below.

With the progress of the electrolytic Ni plating operation, the Ni particles in the basket-shaped anode are gradually consumed and become smaller, and the volume of the whole is reduced. As a result, particularly at the upper portion of the mesh member, the Ni particles become insufficient (not present), and a current flows directly from the anode body portion to the plating bath. O ₂ gas is generated from the plating bath using the anode body as an electrode in a region where a current flows directly from the anode body portion to the plating bath. This generation of O ₂ gas is caused by the reaction of the following formula (1).

From the above equation (1), hydrogen ions are generated in the plating bath on the upper part of the mesh member along with the generation of O ₂ gas. As a result, the pH of the plating bath is greatly lowered at the upper portion of the mesh member.

Above all, when employing a watt bath with electrolytic Ni plating, the watt bath contains boric acid for pH buffering. Even in this case, if the O ₂ gas according to the above-described formula (1) is generated in the plating bath on the upper portion of the mesh member, the pH of the plating bath is greatly reduced.

When the pH decrease of the plating bath is small, the pure-Ti network member is not corroded and is not damaged. However, when the pH of the plating bath reaches the region causing de-passivation of Ti, the net-like Ti network member is corroded and, as a result, is broken.

In this respect, it is presumed that the cause of the corrosion damage due to corrosion at the upper part of the mesh member is that the pH of the plating bath reaches the region causing de-passivation of Ti. Further, the upper limit of the pH at which the passivation of Ti occurs is about 1.

On the basis of this finding, the present inventors have conducted intensive studies on a countermeasure for preventing corrosion of the mesh member even when the pH of the plating bath is significantly lowered. As a result, it has been found out that it is effective to improve the chemical composition of the network member itself based on Ti and to make it a network member made of Ti containing a platinum group element.

When the Ti material contains a platinum group element, the platinum group element is either dissolved in Ti or a Ti-platinum group compound is formed. When the pH of the plating bath becomes significantly lowered, the passive film on the surface is dissolved and Ti begins to melt, and the platinum group element starts to melt. However, since the platinum group element which has started to melt together with Ti has a very valuable redox potential, it is immediately deposited on the surface of the mesh member.

The platinum group element pre-deposited on the surface of the mesh member is a metal having a low hydrogen overvoltage and lowers the hydrogen overvoltage. As a result, the corrosion potential of Ti becomes naturalized and the surface is re-passivated. The dissolution of Ti can be terminated by this re-passivation.

[Basic Test on the Causes of Damage due to Corrosion of Reticular Members and Their Countermeasures]

In order to verify the validity of the above countermeasures, the following basic tests were conducted. In the basic test, in the electrolytic plating employing the watts bath as the plating bath, a situation was observed in which current flows directly from the main body of the basket-like anode to the plating bath. At this time, the cathode (cathode) was regarded as a steel strip to be plated, the anode was regarded as a main body of the basket-shaped anode, and the corrosion resistance of the test piece was examined by viewing the test piece as a mesh-like member of the basket-shaped anode.

1. Preparation of Test Specimens

(1) Comparative material 1: pure Ti

(Two kinds of JIS standard) sheets having a thickness of 1 mm were prepared.

(2) Comparative material 2: The technique described in Patent Document 2

Plate materials of pure Ti (two kinds of JIS standards) having a thickness of 1 mm were obtained, and the surface of the plate made of this pure Ti was subjected to alumina spraying treatment. Specifically, by applying the Ar plasma spraying method and using a plasma jet generated as a plasma event, the alumina of the spraying material (Sankosakaizu: gray alumina Al ₂ O ₃ -2.5% TiO ₂ ) was heated and accelerated Whereby the alumina was melted or close to the melted state and sprayed onto the surface of the plate made of pure Ti to form an insulating film. Since the insulating film had pores, the insulating film was sealed by the PTFE film.

(3) Test material of the present invention example: Improvement of chemical composition based on Ti (titanium alloy)

(a) Raw materials

As raw materials, pure Ti sponge for industrial use (one kind of JIS standard), Pd (palladium) powder with a purity of 99.9% (manufactured by Kishida Chemical Co.), Ru (ruthenium) powder with a purity of 99.9% (Yttrium) (manufactured by Kishida Chemical Co., Ltd.) having a purity of 99.9%, massive rare-earth elements and massive electrolytic Co (cobalt) having a purity of 99.8% were obtained. The massive rare earth element was Mm (Mishmetal: mixed rare earth), La (lanthanum), Nd (neodymium), and the purity was 99% except Mm. The chemical composition of Mm was 28.6% of La, 48.8% of Ce (cerium), 6.4% of Pr (praseodymium) and 16.2% of Nd in mass%.

(b) Preparation of test specimens

An argon melting furnace was used, and the mixing ratio of the raw materials was varied variously to prepare square ingots having different chemical compositions. The size of the square ingot was 15 mm in thickness, 75 mm in width and 95 mm in length. Here, when preparing the angled ingots, five ingots of one 80 g each are first prepared, and then all of the ingots thereof are combined and redissolved to prepare a square ingot having a thickness of 15 mm. Thereafter, Was reused for homogenization to prepare a square ingot of the above-mentioned size.

The prepared rectangular ingot contains a trace amount of platinum group element and occasionally contains a rare earth element. In order to reduce the segregation of each element, a homogenizing heat treatment is performed. The conditions for this homogenization heat treatment were as described above.

, Atmosphere: vacuum ^{(<10 - 3 torr (0.133Pa} ))

Heating temperature: 1100 ° C

· Heating time: 24 hours

The square ingot subjected to the homogenization heat treatment was rolled under the following conditions to finally obtain a plate having a thickness of 1 mm.

? -Phase area Hot rolling: The heating temperature was set to 1000 占 폚, and the thickness of 15 mm was rolled to 9 mm

· Α + β-phase region Hot rolling: The heating temperature was set to 875 ° C., and the thickness was changed from 9 mm to 1 mm

The plate obtained by rolling was annealed for strain relief. The annealing conditions were as described above.

, Atmosphere: vacuum ^{(<10 - 3 torr (0.133Pa} ))

· Heating temperature: 680 ℃

· Heating time: 7 hours

The hot-rolled sheet thus obtained was machined to produce a test piece. Test specimens of the inventive examples and comparative specimens 1 and 2 were all 1 mm in thickness, 15 mm in width and 15 mm in length. The test piece of the present invention example and each of the test pieces of the above comparative material 1 were mirror-polished on the surface using a # 600 buff.

The chemical compositions of the test materials 1 to 17 and comparative materials 1 and 2 of the present invention were as shown in Table 1 below.

The test specimens of comparative materials 1 and 2 are pure Ti. The comparative material 2, which employs the technique described in Patent Document 2, is formed with an insulating film on its surface, and the insulating film is sealed with a PTFE film.

The test pieces of the test materials 1 to 17 of the present invention are all Ti alloys containing a platinum group element. The test materials 5, 6, 9, 11, 15 and 16 further contain Ni, and the test materials 7 to 9, 14 and 17 further contain rare earth elements. The test piece 13 contains two platinum group elements. The test piece 12 is such that the content of the platinum group element is lower than the preferable lower limit of the present invention. The test material 14 is one in which the content of the rare earth element exceeds the preferable upper limit of the present invention. Test materials 15, 16 and 17 are examples of Cr, Al and Zr as impurity elements.

2. Contents of basic test (corrosion resistance investigation)

(1) Test method

3 is a schematic view of a test apparatus used for a basic test of corrosion resistance investigation. The test apparatus used for the foundation test is provided with a plating bath 20 containing a plating solution (plating bath). The plating bath 20 is immersed in a constant temperature bath 21, and it is possible to keep the temperature of the plating liquid in the plating bath 20 constant.

The cathode (22) as seen from the steel strip to be plated was immersed in the plating liquid in the plating bath (20), and the anode (23) was immersed in the body of the basket-like anode. As the cathode 22, a soft steel sheet having a thickness of 1 mm and a width of 20 mm was used. The immersion length of the negative electrode 22 into the plating bath was 20 mm. As the anode 23, pure Ti (two kinds of JIS standards) plate having a thickness of 1 mm and a width of 20 mm was used. The net Ti plate as the anode 23 was cut out from the same material as that used for the comparative member 1 and the immersion length in the plating bath was 20 mm as in the case of the cathode 22.

The test piece 24, that is, the test pieces 1 to 11 and the test pieces of the comparative materials 1 and 2 of the present invention were immersed in the plating solution in the plating bath 20 with the mesh-like member of the basket-type anode. Each test piece 24 was suspended between the positive electrode 23 and the negative electrode 22 by a platinum wire 25 so that neither the positive electrode 23 nor the negative electrode 22 was directly electrically connected.

The plating bath (plating solution) employs a watts bath. The watt bath used was one having a nominal composition of NiSO ₄ (nickel sulfate): 300 to 380 g / L, NiCl ₂ (nickel chloride): 60 to 80 g / L and boric acid: 35 to 55 g / The amount of the watt bath was 60 cc.

In the basic test, a constant current of 3A was continuously supplied to the anode 23 from the DC power supply device for 24 hours, for each of the test pieces 1 to 11 of the present invention and the test pieces of the comparative materials 1 and 2, respectively. At that time, the current density was 37.5 A / dm 2, and the temperature of the watt bath was 55 캜. Further, in order to alleviate the influence of water evaporation of the plating liquid during the test, the plating bath 20 was energized in a state of being covered with a film from above.

(2) Evaluation method

For each test on each test piece, the pH of the plating solution was evaluated. Specifically, the pH of the plating solution was measured by a pH meter (Horiba pH meter D-70 series / ES-71 / OM-71) after 24 hours of operation.

The corrosion rate was evaluated for each test piece. Specifically, assuming that the entire surface of each test piece is corroded uniformly, the following equation (2) is calculated based on the corrosion loss (weight loss) of each test piece by energization for 24 hours and the specific gravity of the test piece (4.51 g / ), The corrosion thickness (mm) per 24 hours was calculated. At that time, the surface area of each test piece was calculated from the thickness, width and length of the test piece before the test.

Corrosion thickness per 24 hours = corrosion loss / (specific gravity x surface area) ... (2)

The corrosion rate (mm / year) after one year from the following formula (3) was obtained from the corrosion thickness per 24 hours calculated from the above-mentioned formula (2).

Corrosion rate = corrosion thickness per 24 hours × 365 days ... (3)

(3) Results of basic tests

The results are shown in Table 2 below.

From the results of the basic tests shown in Table 2, the following are shown. In any of the tests, the pH of the plating solution was 4.6 before the start of the test, but reached a region that caused de-passivation of Ti by significantly lowering 1.0 after 24 hours of energization. In this regard, when a current flows directly from the anode 23 to the plating liquid (plating bath) by the main body of the basket-type anode, if the test piece is pure Ti with the network member of the basket-type anode, the passive film is melted, Quot ;, and &quot;

In the test piece of the comparative material 1, a significant decrease in weight and a decrease in thickness were confirmed in terms of pure Ti which did not contain a platinum group element, and the corrosion rate reached 2.0 mm / year.

Since the surface of the test piece of the comparative member 2 is covered with the insulating film, the occurrence of corrosion is limited to the portion where the formation of the insulating film is incomplete, and the corrosion rate is reduced to about 1/5 of that of the comparative member 1. However, the rate of corrosion was 0.38 mm / year in that it was pure Ti which did not contain a platinum group element.

In the test specimens 1 to 17 of the present invention, the corrosion rate was less than 0.1 mm / year in all of the Ti alloys containing the platinum group element, and remarkable corrosion resistance was confirmed. Particularly, in the test materials 1 to 5, 8, 13, 15 and 16 having a platinum group element content of 0.04 mass% or more, the corrosion rate was less than 0.01 mm / year and the pH of the plating solution was greatly lowered to 1.0, Complete corrosion resistance was confirmed.

In addition, in the test pieces 6, 7, 9, 14, and 17 having a platinum group element content of 0.02 mass% or more and less than 0.04 mass%, the corrosion rate was about 0.02 mm / year. In the test pieces 10 and 11 of the present invention, the content of the platinum group element was less than 0.02 mass%, the corrosion rate was about 0.05 mm / year. In the test piece 12 having the platinum group element content of less than 0.01% by mass, the corrosion rate was 0.1 mm / year. The corrosion resistance of the test specimens 6, 7, 9, 10, 11, 12, 14 and 17 is not limited to the complete corrosion resistance of the test materials 1 to 5, 8, 13, 15 and 16, The comparison clearly improved.

Here, the corrosion rate of the test material 12 is 0.1 mm / year, slightly exceeding the criterion (<0.1 mm / year) which is judged to be intrinsic. The test material 14 is one in which the content of the rare earth element is slightly higher than the desirable upper limit. In this case, the corrosion rate is 0.1 mm / year, which is slightly above the criterion (<0.1 mm / year) that is considered to be intrinsic. The test materials 15, 16 and 17 contained impurities, but had no effect on the corrosion resistance and showed excellent corrosion resistance in this test.

From the result of the basic test as described above, it is understood that it is effective to make the mesh member made of Ti containing a platinum group element to prevent the corrosion of the mesh member of the basket-like anode and to improve the service life of the mesh member.

The basket-type anode of the present invention is completed based on the above findings. Hereinafter, embodiments of the basket-type anode of the present invention will be described.

[Basket-shaped anode according to the embodiment of the present invention]

In the basket-type anode according to this embodiment, the mesh member contains a platinum group element. The mesh member may further contain at least one of Ni and rare earth elements. If the mesh member contains a platinum group element, corrosion of the mesh member can be prevented, and the service life of the mesh member can be improved.

The platinum group element corresponds to six elements of Ru (ruthenium), Rh (rhodium), Pd (palladium), Os (osmium), Ir (iridium) and Pt (platinum). As long as they are selected from these six elements, there is no limitation on the type of the platinum group element. That is, the platinum group element may contain at least one of the six elements. However, since the platinum group element is rare and extremely expensive, from the viewpoint of economical efficiency, it is preferable to select Ru or Pd among the six elements. Ru and Pd have been established for recycling techniques, and among them, Ru can be stably obtained at relatively low cost.

The content of the platinum group element is not particularly limited. However, the incorporation of a large amount of the platinum group element is not preferable from the viewpoint of economical efficiency. Therefore, the upper limit of the content of the platinum group element is preferably 0.15 mass%. More preferably, the upper limit of the content of the platinum group element is 0.08 mass%.

The lower limit of the content of the platinum group element is preferably 0.01% by mass in order to sufficiently improve the lifetime of the mesh member. More preferably, the lower limit of the content of the platinum group element is 0.02 mass%, more preferably 0.04 mass%.

Here, if Ni or a rare earth element is additionally contained in addition to the platinum group element, it is possible to reduce the content of the platinum group element by the synergistic effect due to the inclusion of Ni or a rare earth element. Therefore, the incorporation of Ni or a rare earth element has an advantage in terms of economy.

Like the platinum group element, Ni has an effect of lowering the hydrogen overpotential and naturalizing the corrosion potential of Ti. In order to obtain this effect, when Ni is contained for the purpose of reducing the content of the platinum group element, the lower limit of the Ni content is preferably 0.2 mass%. The lower limit of the Ni content is more preferably 0.4% by mass. On the other hand, the incorporation of a large amount of Ni causes deterioration of workability and moldability. For this reason, when the Ni is contained, the upper limit of the Ni content is preferably 1.0% by mass.

The rare earth element has the effect of accelerating all the platinum group elements to the surface of the Ti material containing the platinum group element when the Ti material is exposed to the corrosive environment in the content of Ti contained in the Ti. In order to obtain this effect, when the rare earth element is contained, the lower limit of the content of the rare earth element is preferably 0.0005 mass%. The lower limit of the content of the rare earth element is more preferably 0.001 mass%. On the other hand, when the rare earth element is excessively contained, rare earth element alone may precipitate, and the precipitated rare earth element may be a factor of corrosion. Although the upper limit of the content of the rare earth element is the upper limit of the employment range of the rare earth element in view of the mechanism, there is a possibility that segregation or the like may occur at the time of dissolution. Therefore, when the rare earth element is contained, the upper limit of the content of the rare earth element is preferably set to 0.020 mass% from the viewpoint of ensuring the solid state of solidification.

The rare earth element is a generic term of 17 elements in which Y and Sc are added to 15 elements of lanthanoid from La of atomic number 57 to Lu of atomic number 71, and may contain at least one selected from these elements . The content of the rare earth element means the total content of these elements.

As described above, the net-like member (netting) of the basket-type anode of the present embodiment is a titanium material, and contains a platinum group element, and in some cases, at least one of Ni and rare earth elements. Examples of the impurity element other than these elements include Fe, O, C, H and N which enter from a raw material, a dissolution electrode and the environment, and Al, Cr, Zr, Nb, Si, Sn, Mn, Co, and Cu. These impurity elements may be mixed if they do not impair the effect of the present embodiment. Specifically, it is preferable that the steel material contains at least one of Fe, at most 0.3%, at most 0.35% of O, at most 0.18% of C, at most 0.015% of H, at most 0.03% of N, at most 0.3% 0.2% or less of Zr, 0.2% or less of Nb, 0.02% or less of Si, 0.2% or less of Sn, 0.01% or less of Mn, 0.35% or less of Co and 0.1% or less of Cu There is no problem.

The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the present invention. For example, the basket-type anode of the present embodiment can be suitably used for electrolytic Ni plating in which the plating raw material particles are Ni particles and a watts bath is employed as the plating bath. However, as long as it is used for electrolytic plating, There is no limitation on each type of plating bath. As the classification of the plating material particles, that is, plating, applicable to the basket-type anode of the present embodiment, there are gold, silver, copper, tin and zinc in addition to Ni. Examples of the shape of the plating raw material particle include a spherical shape and a crown shape. As the type of plating bath to which the basket-type anode of the present embodiment can be applied, nickel sulfate high-speed bath, nickel sulfate high-speed bath, strike bath (wood bath), black nickel plating bath, have.

Example

In order to confirm the effect of the present invention, the basket type anode shown in Figs. 1 and 2 was used, and the electrolytic Ni plating line employing the watts bath as the plating bath actually performed the operational test.

[Exam conditions]

In the test, five kinds of reticulated members (strictly, a netting) were prepared. Three test materials 21, 22 and 23 having different chemical components were applied to the mesh member of the present invention as shown in Table 3 below. Two comparative materials 1 and 2 having the same chemical composition but different surface morphology were applied to the mesh member of the comparative example.

As shown in Table 3, the reticular members of the test materials 21, 22 and 23 of the present invention were all made of a Ti alloy containing a platinum group element. The mesh member of the test material 21 further contains Ni, and the mesh member of the test material 23 further contains Mm (Mish Metal: mixed rare earth) as a rare earth element. On the other hand, all of the network members of the comparative members 21 and 22 were made of pure Ti (two kinds of JIS standards). The mesh member of the comparative member 22, as in the comparison member 2 in the basic test described above, was made by applying alumina thermal spray treatment to the surface of the net.

These five types of mesh members were provided as mesh members at the top of the basket type anode, respectively. Then, each basket-type anode was immersed in the same watt bath, and electrolytic Ni plating was continuously applied to the surface of the steel strip. This electrolytic Ni plating was continuously operated for three months.

The composition of the watt bath was nickel sulfate: about 340 g / L, nickel chloride: about 70 g / L, and boric acid: about 45 g / L. The temperature of the watt bath was about 55 캜, and the pH of the watt bath was 3.5 to 4.6. In addition, the anode main body had a current density of 34.5 A / dm 2 at the normal time, and an electrolytic voltage of about 30 V was continuously conducted. Each basket-type anode was charged with crown-type Ni particles and replenished periodically. At that time, just under the liquid surface of the watt bath, with the consumption of the Ni particles, only the plating liquid was often present.

[Assessment Methods]

After three consecutive months of operation, the conditions of corrosion and the loss of welding were investigated with respect to the uppermost mesh member of each basket-type anode. In this investigation, the presence or absence of a flaw was visually confirmed on the entire surface of the uppermost mesh member after continuous operation.

In this investigation, the net thickness of each mesh member was measured before and after the continuous operation, and the degree of corrosion was evaluated from the reduction in the thickness. The net thicknesses of the mesh members were measured at three predetermined points A, B, and C, respectively. The measurement point A was located at a position that was 50 mm inward from the left end and 200 mm below the upper end of the mesh member at the uppermost stage. The measurement point B is a point located at the center of the leftmost and rightmost center of the uppermost mesh member and a point 200 mm below the uppermost portion thereof. The measurement point C was located at a position that was 50 mm inward from the right end and 200 mm below the upper end of the mesh member at the uppermost stage. These measurement points A, B, and C correspond to positions immediately under the liquid surface of the watt bath, and they are positions where breakage of the reticular member is likely to occur.

[result]

The results are shown in Table 4 below.

In the mesh member of the comparative member 21, the thickness of the net was reduced to 1/2 or less even if a part of the net was corroded and melted and remained. Further, in the mesh member of the comparative member 22, it was confirmed that the thickness of the mesh due to corrosion was reduced in the portion where the formation of the insulating coating was incomplete. On the contrary, in the mesh members of the test materials 21 to 23 of the present invention, no reduction in the thickness of the mesh due to corrosion was observed at all.

From the above results, it was demonstrated that the basket-type anode of this embodiment can improve the lifetime of the mesh member.

&Lt; Industrial applicability >

The basket-type anode of the present invention can be effectively used for all electrolytic plating.

1: Basket type anode
2: anode body portion
2a: rear plate
2b, 2c: side plates
2d: bottom plate
2e: bus bar
3:
3a, 3b:
4: Holding
5: Pressure plate
6: Bolt
7: Bag
10: Plating raw material particles
11: Plating bath
12: Coils
20: Plating bath
21: Incubation bath
22: cathode (cathode)
23: anode
24: Specimen
25: platinum wire

Claims (7)

A basket-type anode used for electrolytic plating of steel strips containing plating material particles in a plating bath,
Wherein the basket-shaped anode has a mesh-like member made of Ti disposed opposite to the steel strip, and the mesh-shaped member contains a platinum group element. The basket-type anode according to claim 1, wherein the content of the platinum group element is 0.01% to 0.15% by mass. The basket-type anode according to claim 1 or 2, wherein the mesh member further contains at least one of Ni and rare earth elements. The basket-type anode according to claim 3, wherein the Ni content is 0.2% to 1.0% by mass%, and the content of the rare earth element is 0.0005% to 0.020% by mass%. 4. The ferritic stainless steel according to any one of claims 1 to 4, which contains, as a mass%, Fe: not more than 0.3%, O: not more than 0.35%, C: not more than 0.18%, H: not more than 0.015% At most 0.2% of Al, at most 0.2% of Cr, at most 0.2% of Zr, at most 0.2% of Nb, at most 0.02% of Si, at most 0.2% of Sn, at most 0.01% Cu: not more than 0.1% in total not more than 0.6%. The basket-type anode according to any one of claims 1 to 5, wherein the plating material particles are Ni particles. 7. The basket-type anode according to any one of claims 1 to 6, wherein the plating bath is a watt bath.

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