JPH07278882A - Electroplating method and device therefor - Google Patents

Abstract

PURPOSE:To prevent nonuniform plating by electroplating a material while irradiating the material with an ultrasonic wave of specified frequency. CONSTITUTION:In the electroplating process generating gas, a material 1-11 is plated while irradiating the material with the ultrasonic wave of >=400kHz, preferably >=800kHz frequency. In this case, an ultrasonic vibrator 1-13 is arranged adjacent to a counter electrode 1-9 or opposed to the counter electrode 1-9 through the material 1-11. The effect of the irradiation with the ultrasonic waver is enhanced by controlling the angle between the lower surface of a metallic body to be plated and horizontal plane to >=about 5 deg..

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electroplating method and apparatus.

[0002]

2. Description of the Related Art Zn-based electroplated steel sheets have been widely produced for applications such as steel sheets for automobiles, but sometimes the surface gloss of a plated layer is different (hereinafter referred to as uneven plating). Even if surface unevenness is applied to the uneven plating portion, the appearance is still different from other portions, so that the Zn-plated steel sheet with uneven plating has a markedly low commercial value, and in extreme cases, the commercial value is completely lost. In addition, other plated products usually require a uniform surface condition. Therefore, the occurrence of plating unevenness is a very important problem that directly leads to a reduction in product yield, and there is a strong demand for the development of an industrial technique for suppressing the occurrence of plating unevenness in various industries.

[0003] As a method for producing an electrogalvanized steel sheet having excellent appearance uniformity without uneven plating, for example, JP-A-4-74887 and JP-A-4-74888 disclose an acidic electrogalvanizing bath containing an electric conductivity aid. Discloses a method of forming a lower layer plating, and then forming an upper layer plating in another zinc plating bath containing no conductivity auxiliary agent. But,
None of the conventional electroplating methods have been able to cover delicate appearance stains (unevenness of plating).

On the other hand, regarding the technique of utilizing ultrasonic waves, for example, Japanese Patent Application Laid-Open No. 3-68789 discloses a technique of a pickling method and a pickling apparatus by ultrasonic vibration of a wire coil. This invention is a pickling method in which ultrasonic vibration is added to remove the scale generated on the surface of the wire coil by pickling, in order to shorten the time until descaling and to clean the coil surface after pickling. And the pickling device, the ultrasonic transducer is installed within 900 mm of the pickling surface and 700 mm from the wire coil surface.
It is limited to the following. Although the frequency of ultrasonic waves is not particularly specified, it can be read from the description of the actions and examples in the specification that the invention relates to ultrasonic waves having a frequency of 28 kHz, and the special effect of high-frequency ultrasonic waves in the present invention is obtained. Is not described at all. JP-A-3-1584
Japanese Patent Publication No. 49 discloses a technique relating to a method for manufacturing a galvannealed steel sheet using ultrasonic vibration. The present invention is to dip a Ti-containing steel sheet in a hot dip zinc bath containing Al to produce an alloyed hot-dip galvanized steel sheet excellent in appearance and workability while applying ultrasonic vibration to the steel sheet. Although the frequency of the ultrasonic wave is not particularly specified, it can be read from the description of the action in the specification that the invention relates to the ultrasonic wave having a frequency of 5 kHz or more, and the description of the example relates to the ultrasonic wave having a frequency of 30 kHz. No mention is made of the special effects of ultrasound.

As described above, the method of preventing uneven plating in the electroplating process or the method of producing an electroplating material excellent in appearance uniformity based on the effect of ultrasonic irradiation of high frequency as in the present invention has been conventionally used. , It was unknown, and no similar manufacturing technology was known.

[0006]

As described above, there has been a strong demand for the development of an industrial technique for suppressing the occurrence of uneven electroplating in various industries. In view of such circumstances, it is an object of the present invention to provide a method and an apparatus for preventing uneven plating in an electroplating process involving gas generation.

[0007]

The electroplating method and apparatus of the present invention perform plating in an electroplating process involving gas generation while irradiating a material to be plated with ultrasonic waves having a high frequency of 400 kHz or more. A metal strip where the plating material moves with respect to the plating solution,
In an electroplating process in which the counter electrode is arranged on the front surface and / or the back surface side, an ultrasonic transducer having a frequency of 400 kHz or more is installed adjacent to the counter electrode or at a position facing the counter electrode through a material to be plated. A metal strip where the plating material moves with respect to the plating solution,
In an electroplating process in which a counter electrode and an ultrasonic vibrator are provided on the front surface and / or the back surface side, and the counter electrode and the ultrasonic vibrator are installed parallel to the metal band with a certain distance from the metal band surface. , Within the vertical plane that is perpendicular to the vertical plane parallel to the moving direction of the metal band to be plated, or within the vertical plane parallel to the moving direction of the metal band to be plated, the angle between the bottom surface of the metal band to be plated and the horizontal plane is It is as described in item 2, which is 5 degrees or more.

In the above description, "the material to be plated moves with respect to the plating solution" means (1) the plating solution flows to the material to be plated (metal strip) in a stationary state, or (2)
This means a state in which the material to be plated (metal band) moves with respect to the stationary plating solution, or (3) both the plating solution and the material to be plated (metal band) move. The "moving direction of the metal strip to be plated" in the above means the moving direction of the plating solution when the above-defined condition "the material to be plated moves with respect to the plating solution" is (1), or 2)
In the cases of (3) and (3), it means the moving direction of the material to be plated (metal band). Further, the counter electrode in the above is an anode electrode for electroplating.

[0009]

In the following, description will be made by taking as an example the case where the electric steel is plated with Zn. In the electric Zn plating line, uneven plating sometimes occurs. The present inventors have made various studies on the cause of uneven plating, and the bubbles generated during electroplating cause uneven plating. When the material to be plated is a flat plate like a steel plate, it becomes the lower surface during plating. It was found that uneven plating is likely to occur on the side. Further, during plating, for some reason, for example, when the existence rate of bubbles on the steel sheet is uneven due to the non-uniform bubble separation rate and bubble generation reaction rate, regardless of the upper surface or the lower surface,
It has been found that there is a tendency to cause uneven plating.

Therefore, the present inventors have forcibly removed air bubbles generated during electroplating by some means,
Various experiments were conducted on the assumption that uneven plating can be prevented by frequently changing the adhesion position, breaking up into minute bubbles, or combining these actions. As a result, a frequency of 400 kHz or higher, preferably 800 kHz
It was confirmed that such a situation would occur if plating was performed while irradiating the material to be plated with ultrasonic waves having a high frequency of Hz or higher, and uneven plating was less likely to occur, and the invention of claim 1 of the present invention was completed. I arrived. The inventors have made various studies on the arrangement of the ultrasonic transducer, and it is suitable for continuous electroplating on the metal strip to install the ultrasonic transducer at a position adjacent to the counter electrode or at a position opposite to the electrode via the material to be plated. It was confirmed that the invention of claim 2 of the present invention was completed. When the electroplating is continuously performed while the metal strip to be plated (steel plate) is moved with respect to the plating solution, the present inventors are orthogonal to the vertical plane parallel to the moving direction of the metal strip to be plated. If the angle between the lower surface of the metal strip to be plated (steel plate) and the horizontal plane is 5 degrees or more in the vertical plane that is parallel to the moving direction of the metal strip to be plated, the effect of ultrasonic irradiation is enhanced. It was confirmed that the invention of claim 3 of the present invention was completed.

The device of the present invention is shown, for example, in FIGS.

In FIG. 1, the plating solution extruded by the liquid feed pump 1-1 through the pipe 1-2 and the pipe 1-3 to the connector 1-5 is the plating cell wall 1-7 and the plating cell wall 1-8. The channel portion formed by
Flows at high speed inside. Counter electrode (anode) 1 for plating cell
-9 and a material to be plated (cathode) 1-11 are arranged, and electroplating is performed by applying a voltage between them. Although the counter electrode 1-9 is an insoluble electrode, it may be a soluble electrode such as a Zn electrode for Zn plating and a Cu electrode for Cu plating. An ultrasonic vibrator 1-13 is provided below the material to be plated via an ultrasonic medium (water) 1-12, and electroplating is performed while oscillating the material to be plated 1-11 by high-frequency ultrasonic waves. be able to. Although not shown, ultrasonic medium (water) 1-1
A pipe for venting air and a pipe for exchanging an ultrasonic medium to prevent overheating are installed in a portion filled with 2. High-speed plating solution for connector 1-6 and piping 1
-4, is collected in a plating solution tank (not shown),
Furthermore, it returns to the liquid feed pump 1-1 through a pipe (not shown). Although not shown, the plating solution tank contains a temperature control unit, a rectifying unit, a filter, a bubble removing unit, and the like. In the apparatus of FIG. 1, the pipe 1
-3, piping 1-4, connector 1-5, connector 1-
The entire electroplating cell including 6 can be rotated around a horizontal axis or can be rotated up and down, whereby it is orthogonal to the vertical plane parallel to the moving direction of the material to be plated (metal strip). Within the vertical plane or material to be plated (metal strip)
It is possible to change the angle between the lower surface of the material to be plated (metal band) and the horizontal plane in the vertical plane parallel to the moving direction of. Further, by rotating the electroplating cell up and down 180 degrees, the upper surface or the lower surface of the material to be plated can be plated.

In FIG. 2A, the plating solution supplied from the plating solution jet nozzle 2-9 is the counter electrode (anode) 2-.
10, ultrasonic transducer 2-11, and guide plate 2-12
It flows at high speed through the channel part formed by. There is a metal strip 2-13 at the center of the channel part,
-3 moves in the opposite direction to the plating solution. Electroplating is performed by applying a voltage between the metal strip 2-13 and the counter electrode (anode) 2-10 via the conductor roll 2-1. Although the counter electrode 2-10 is an insoluble electrode, it may be a soluble electrode such as a Zn electrode for Zn plating and a Ni electrode for Ni plating. The ultrasonic vibrator 2-11 irradiates the metal band 2-13 with high-frequency ultrasonic waves through the plating solution. Ultrasonic transducer 2
-11 may be adjacent to the counter electrode 2-10 as shown in FIG. 2 (a), or as shown in FIG. 2 (b) at a position facing the counter electrode via the metal strip 2-13 (material to be plated). You may install it. The metal strip 2-13 that has passed through the drive roll 2-3 is a rinse tank 2-7 filled with a rinse liquid (water) 2-8, a squeeze roll 2-4 for removing the rinse liquid, and a rubber roll (movable).
It enters the plating tank 2-6 again via 2-5. The metal strip 2-13 has a loop shape due to welding, and is repeatedly subjected to the above cycle until a predetermined amount of electroplating is performed. Although not shown, in this device, a metal strip coil which is a raw material for forming the loop-shaped metal strip 2-13,
A shear for coil cutting, a spot welding machine, etc. are attached. When the predetermined electroplating is completed, the energization and the supply of the plating solution by the plating jet nozzle 2-9 are stopped,
At the same time as discharging the plating solution from the plating tank 2-6, the movement of the metal strip 2-13 is stopped. In this state, the portions held in the plating tank 2-6 and the rinsing tank 2-7 cause reactions such as corrosion, and therefore were not used for evaluation of uneven plating.

The method and apparatus of the present invention are not limited to the embodiments and those shown in FIGS. 1 and 2, for example, the Iron and Steel Handbook, VI, pp 414, FIGS. 10 and 13, or pp, 420, FIGS. It may be used by being incorporated in a continuous production line as shown in FIG. It can also be used in various types of electroplating cells shown in FIGS. 10, 14 to 10 and 17 of pp414 of the same manual.

In principle, the three methods and devices of the present invention are also effective for electrically conductive objects (semiconductors, metals) other than steel plates. For example, when a plastic film and a copper plate vapor-plated with Au were subjected to the same experiment as the steel strip using the apparatus shown in FIG. 1, the effect of suppressing ultrasonic waves on the occurrence of uneven plating was confirmed. The same effect was obtained when electroplating was performed on a steel material having a curved shape such as a steel tube that was split vertically. Therefore, the method and apparatus of the present invention are effective not only for steel plates but also for general electrically conductive objects including metal strips, and are not affected by the shape of the material to be plated. In principle, the method and apparatus of the present invention are effective for suppressing the occurrence of uneven plating even in the case of electroplating other than Zn. For example, as shown in Example 4, the steel strip has N
When an experiment for i-plating was performed, the effect of suppressing ultrasonic waves on the occurrence of uneven plating was confirmed. Therefore, the method and apparatus of the present invention is applicable to electroplating processes in general with gas generation.

In the present invention, the frequency of ultrasonic waves is 400 k
The reason for limiting to above Hz is as follows. Example 1
As shown as a comparative example in, the frequency of the ultrasonic wave is 1
At a frequency of about 50 kHz or less, no effect of suppressing uneven plating is observed. On the other hand, 400kH
Above z, a clear suppression effect was observed, 800 kHz
The above is remarkable. For the above reasons, the frequency of ultrasonic waves in the present invention is set to 400 kHz or higher.

The present inventors believe that the difference in the ultrasonic effect due to the above frequency occurs because the property of the ultrasonic wave changes with the increase of the frequency. In the conventional industrial technology, it is common to use ultrasonic waves in the frequency band of 20 to 40 kHz, and exceptionally 70 to 200 kHz.
I sometimes used the z band. 200k like this
The action of ultrasonic waves in the frequency band below Hz is caused by a standing wave (standing wave). Standing waves are seen when the distance between the surface to be irradiated that reflects ultrasonic waves and the ultrasonic transducer becomes an integral multiple of half the wavelength of the ultrasonic wave, and if this condition is not satisfied. Ultrasound cannot exist stably. The standing wave consists of a traveling wave traveling from the ultrasonic transducer toward the irradiated surface and a reflected wave traveling from the irradiated surface toward the ultrasonic transducer, and a strong compressive force (cohesive force) is generated by their interaction. A place and a place where a strong dispersive force are generated alternately appear to cause cavitation, and when the cavity is deformed or ruptured, its periphery is vibrated, and ultrasonic action such as increased cleaning power appears.

On the other hand, in the case of a high frequency ultrasonic wave having a frequency of 400 kHz or more, an ultrasonic wave action different from the above action appears. A characteristic of high-frequency ultrasonic waves is that they have a short wavelength, and because they are very easily scattered when irradiated to the object to be irradiated, reflected waves do not return to the ultrasonic vibrator, and the above-mentioned constant Standing waves are unlikely to occur. Therefore, although the ultrasonic action due to cavitation does not appear, the following ultrasonic action due to the large acceleration given to the object to be irradiated and the medium (hereinafter referred to as the acceleration effect) appears. The maximum value of the force and the acceleration applied to the medium or the object to be irradiated by the ultrasonic wave is proportional to the square of the frequency and the amplitude (strength) of the ultrasonic wave, so that the acceleration effect remarkably increases as the frequency increases. The frequency of acceleration effect is 200
Although it should be seen in principle at a frequency of less than kHz, it can be said that the ultrasonic effect due to standing waves and cavitation is the main component, and there is virtually no acceleration effect. 200 to 400 kHz is a transition region in which ultrasonic action due to standing waves and cavitation shifts to an acceleration effect, and at 400 kHz or higher, the acceleration effect is the main component. 400 kHz against uneven plating
The above high-frequency ultrasonic waves have a suppressing effect because the acceleration effect causes the air bubbles adhering to the material to be plated and the surface of the material to be strongly shaken, causing the air bubbles to separate from the surface or to be frequently attached. It is considered that the electroplating reaction proceeds uniformly because the position is changed, the bubbles are divided into minute bubbles, or their actions are combined. In addition, cavitation is less likely to occur with high-frequency ultrasonic waves, and the plating layer is not damaged by plastic deformation or the like, so that the electroplating reactivity on the surface of the material to be plated does not vary depending on the location or time. This is also considered to contribute to the suppression of uneven plating. Although the frequency of the ultrasonic wave used is fixed in the embodiment of the present invention, the frequency is 400 kHz or more, preferably 8 kHz.
If the frequency is 00 kHz or more, a method of changing the frequency with time (the so-called SWEEP method corresponds to this and normally changes the frequency periodically within a range of ± several kHz) may be used.

Conventional ultrasonic waves (frequency less than 200 kHz)
Since the ultrasonic action is based on standing waves, it is necessary to keep the distance between the plated material and the vibrator constant.
While the effect decreases significantly as the distance changes,
The acceleration effect of high-frequency ultrasonic waves is hardly affected even if the distance between the material to be plated and the vibrator changes slightly.
When electroplating is continuously performed while the strip to be plated is moving like a Zn electroplated steel sheet, the strip to be plated may vibrate and the distance to the vibrator may fluctuate. Irradiation with ultrasonic waves (frequency less than 200 kHz) may even induce uneven plating. On the other hand, in the case of the high-frequency ultrasonic wave of the present invention, such a phenomenon does not occur, and the effect of suppressing plating unevenness appears clearly. Further, the magnitude of the acceleration effect hardly changes even if the distance between the object to be plated and the vibrator fluctuates to some extent, and therefore it is also suitable for the object to be plated having an uneven surface. For the same reason, there is no limitation on the distance between the vibrator and the material to be plated. In the present invention, the power applied to the ultrasonic transducer is not particularly limited. As will be apparent to those skilled in the industrial field related to the present invention, the magnitude of power depends on the amount of gas generated during electroplating, the distance between the ultrasonic transducer and the material to be plated, and the desired uniformity of the appearance of the plated layer surface. This is because it is comprehensively determined depending on the degree of, and other conditions, and the optimum conditions differ depending on individual cases. Taking Zn plating as an example, it is preferable to use ultrasonic waves having a power of 0.1 W / cm ² or more under normal electroplating conditions.

In claim 2 of the present invention, the reason why the ultrasonic transducer is installed adjacent to the counter electrode or at a position facing the counter electrode through the material to be plated and the installation position is limited is as follows. . It is preferable to install the ultrasonic vibrator as close as possible to the steel plate.For example, if it is installed between the counter electrode and the material to be plated, not only will the electroplating reaction be hindered and macroscopic uneven plating will occur, but Since the vibrator has a certain size, the distance between the counter electrode and the material to be plated must be increased, resulting in an increase in the electrical resistance between the counter electrode and the material to be plated, resulting in a decrease in current efficiency. , Not preferable. It is preferable that the ultrasonic vibrator is adjacent to the counter electrode because not only such a problem can be prevented but also the flow of the plating solution is not hindered. In addition, it is preferable to install the ultrasonic vibrator at a position facing the counter electrode via the material to be plated, since there is no such inconvenience as described above. For the above reason, in claim 2 of the present invention, the ultrasonic transducer is installed adjacent to the counter electrode or at a position facing the counter electrode through the material to be plated, and the installation position is limited.

According to claim 3 of the present invention, in a vertical plane orthogonal to a vertical plane parallel to the moving direction of the metal strip to be plated,
The reason why the angle between the lower surface of the metal band to be plated and the horizontal plane is limited to 5 degrees or more in the vertical plane parallel to the moving direction of the metal band to be plated is as follows. As shown in Example 2, when the angle is 5 degrees or more, the effect of suppressing the occurrence of plating unevenness due to the irradiation of high-frequency ultrasonic waves becomes more remarkable than when the angle is zero. On the other hand, when the angle is less than 5 degrees, the effect is not so different from the case where the angle is zero. Therefore, according to claim 3 of the present invention, the metal strip to be plated is in a vertical plane orthogonal to the vertical plane parallel to the moving direction of the metal strip to be plated, or in a vertical plane parallel to the moving direction of the metal strip to be plated. The angle between the lower surface and the horizontal surface is limited to 5 degrees or more. When the angle between the lower surface of the metal band to be plated and the horizontal plane is about 90 degrees in the vertical plane parallel to the moving direction of the metal band to be plated, a so-called vertical type plating cell is obtained. Is also applicable to such electroplating processes. In the present invention, the upper limit of the angle is not specified. However, in a vertical plane that is orthogonal to a vertical plane parallel to the moving direction of the metal band to be plated, if the angle formed by the lower surface of the metal band to be plated and the horizontal plane increases, the metal band may slip off. The following are preferred.

[0022]

【Example】

Example 1 A hot rolled material of low carbon steel having a plate thickness of 4 mm was pickled so that the scale remained extremely thin, and then cold rolled to a plate thickness of 0.8 mm, which was annealed to obtain a plating original plate. . On the upper surface of such an original plate, using the liquid circulation type electroplating apparatus shown in FIG. 1 (one embodiment of the apparatus of the present invention), a pH of 1 containing Zn ions of 70 g / L and a bath temperature of 60 ° C. In a sulfuric acid bath, the flow rate was 1 m / sec, the current density was 100 A / dm ² ,
Zn deposition amount is 20 g / m ²
I went 0 times. However, since the original plate was not irradiated with ultrasonic waves, this method is a comparative example and is not the method of the present invention. In addition, the plating cell of FIG. 1 was rotated 180 degrees and turned upside down with respect to the tip, and the lower surface of the original plate was similarly tested 10 times. The uneven plating was evaluated as follows. The appearance of the plating layer in a 100 mm × 200 mm section at the center of a 150 mm × 300 mm plated plate was observed, the number of spots where uneven plating was generated was counted, and the average value for 10 plates was used as the score. When the top surface was plated, uneven plating was observed on 8 sheets, and the rating was 1.3. 10 when plated on the bottom surface
Occurrence of uneven plating was observed on all the sheets, and the score was 2 or more. The unevenness of plating was more severe on the lower surface than on the upper surface.

Frequencies 28, 40, and 150 kHz,
The same test was performed while irradiating the surface of the plating original plate opposite to the surface to be plated with ultrasonic waves having a power density of about 0.5 W / cm ² . This method is also a comparative example because the frequency of the applied ultrasonic waves is low, and is not the method of the present invention. The scores and the degree of uneven plating were not significantly different from those in the case where the ultrasonic wave was not irradiated, and no improvement in uneven plating was observed.

On the other hand, frequencies 400, 600, 80
0,1000,1500kHz, power density about 0.5W
/ Cm at the ^second ultrasound plated surface of the plated original plate was subjected to the same plating test as above in the method of the present invention while irradiating the surface opposite each plating unevenness scores, 0 relative to the upper surface .5, 0.2, 0.0, 0.0, and 0.
0, 0.6, 0.2, 0.0, 0.0, and 0.0 for the lower surface. Moreover, the degree of uneven plating was extremely slight, and the occurrence of uneven plating was significantly suppressed by the method and apparatus of the present invention.

Example 2 Using the method and apparatus of the present invention described in Example 1 (FIG. 1), while irradiating ultrasonic waves having frequencies of 400, 600 and 800 kHz and a power density of about 0.5 W / cm ² ,
Zn plating was performed on the lower surface of the plating original plate. However, in the vertical plane perpendicular to the vertical plane parallel to the moving direction of the plating solution, the angle formed by the lower surface of the original plating plate and the horizontal plane is 5
And 10 degrees. The uneven plating scores are 0.2, 0.1, and 0.0, respectively, when the angle is 5 degrees.
And 0.1, 0.0, and 0.
It was 0. In general, the degree of uneven plating was extremely slight. A similar test was conducted with the angle of 3 degrees, but was not much different from the case where the angle was 0 degree described in Example 1 (method and apparatus of the present invention). Next, in the vertical plane parallel to the moving direction of the plating solution, the same experiment as above was conducted with the angle between the lower surface of the original plating plate and the horizontal plane being 5 degrees and 10 degrees. The uneven plating score is 5 for each of the above angles.
0.3, 0.1, and 0.0 for degrees, 1
It was 0.1, 0.0, and 0.0 at 0 degrees. In general, the degree of uneven plating was extremely slight. Furthermore, the same test was conducted with the angle being 3 degrees, but it was not so different from the case where the angle described in Example 1 was 0 degree (method and apparatus of the present invention). From the above, it was found that by the method and apparatus of the present invention in which the angle is 5 degrees or more, the occurrence of plating unevenness is further suppressed as compared with the case where the angle is 0 degree.

Example 3 A low-carbon steel hot-rolled material having a plate thickness of 4 mm was pickled, and then cold-rolled to a plate thickness of 0.3 mm, which was annealed, washed and dried to form a steel strip of a plating original plate. And With the apparatus shown in FIG. 2 (a) (one example of the apparatus of the present invention), in a sulfuric acid bath having a pH of 1 containing Zn ions of 70 g / L and a bath temperature of 60 ° C., a liquid flow rate of 1 m / sec and a strip speed of 0. .5M / sec, as a current density of 100A / dm ^2, the frequency 1000 kHz, while applying ultrasonic power density of about 2.0 W / cm ² on the upper and / or lower surface of the plated steel strip, electric Zn in the method of the present invention Plated. Zn adhesion is about 3 per side
It was set to 0 g / m ² . When the upper surface and the lower surface of the steel strip were evaluated, no Zn plating unevenness was found to occur. On the other hand, when it was performed without irradiating ultrasonic waves, uneven plating occurred. However, at the end of electroplating, the portions held in the plating bath 6 and the rinse bath 7 cause reactions such as corrosion, and therefore were not used for evaluation of uneven plating.

Example 4 A hot rolled material of low carbon steel having a plate thickness of 4 mm was pickled, and then cold rolled to a plate thickness of 0.8 mm, which was annealed to obtain a plating original plate. On the upper surface of such an original plate, 240 g / L of NiSO ₄ , NiCl ₄ was used by using the liquid circulation type electroplating apparatus shown in FIG. 1 (one embodiment of the apparatus of the present invention).
_In a plating bath having a bath temperature of 60 ° C. containing 45 g / L as _{2 and} 30 g / L as H ₃ BO ₃ , the flow rate was 1 m / L.
Second, current density 14 A / dm ² , Ni deposition amount 10 μm
Frequency 800 kHz, power density about 0.5 W /
When electric Ni plating was carried out by the method of the present invention while irradiating the plating original plate with ultrasonic waves of cm ² , no uneven plating was found. On the other hand, when it was performed without irradiating ultrasonic waves, uneven plating occurred.

Example 5 A hot rolled material of low carbon steel having a plate thickness of 4 mm was pickled, and then cold rolled to a plate thickness of 0.8 mm, which was annealed to obtain a plating original plate. On the upper surface of such an original plate, 200 g / CuSO ₄ .5H ₂ O was used by using the liquid circulation type electroplating apparatus shown in FIG. 1 (one embodiment of the apparatus of the present invention).
In a sulfuric acid bath containing 40 g / L of L and H ₂ SO _{4 at} a bath temperature of 40 ° C., a flow rate of 1 m / sec and a current density of 20 A
/ Dm ² , and the amount of Cu deposited is 50 g / m ² , the frequency is 8
Electroless Cu plating was carried out by the method of the present invention while irradiating the original plating plate with ultrasonic waves of 00 kHz and power density of about 5 W / cm ² , and no uneven plating was found.

[0029]

According to the method and apparatus of the present invention, it is possible to remarkably suppress the occurrence of plating unevenness, and reduce the proportion of defective materials in various electroplating fields in which uniformity of surface appearance and beauty are required. This will not only reduce the material cost but also contribute to the maintenance of the global environment.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an electroplating apparatus of the present invention.

2A and 2B are views showing another embodiment of the electroplating apparatus of the present invention.

[Explanation of symbols]

1-1 ... Liquid feed pump 1-2 ... Piping 1-3 ... Piping (plating solution inlet) 1-4 ... Piping (plating solution outlet) 1-5 ... Connector 1-6 ... Connector 1-7 ... Plating cell wall 1 -8 ... Plating cell wall 1-9 ... Counter electrode (anode) 1-10 ... Plating liquid channel part 1-11 ... Plated material (cathode) 1-12 ... Ultrasonic medium (water) 1-13 ... Ultrasonic transducer 2-1 ... Conductor roll 2-2 ... Rubber roll 2-3 ... Drive roll 2-4 ... Drawing roll 2-5 ... Rubber roll 2-6 ... Plating tank 2-7 ... Rinsing tank 2-8 ... Rinsing liquid (water) 2 -9 ... Plating solution jetting nozzle 2-10 ... Counter electrode (anode) 2-11 ... Ultrasonic transducer 2-12 ... Guide plate 2-13 ... Metal strip 2-14 ... Guide plate

Front page continuation (72) Inventor Masao Sakashita 1618 Ida, Nakahara-ku, Kawasaki-shi Nippon Steel Corporation

Claims (3)

[Claims] 1. An electroplating method, wherein plating is performed while irradiating a material to be plated with high frequency ultrasonic waves having a frequency of 400 kHz or more in an electroplating process involving gas generation. 2. A frequency of 40 in an electroplating process in which a material to be plated is a metal strip that moves with respect to a plating solution and a counter electrode is arranged on the front surface and / or the back surface side.
An electroplating apparatus, wherein an ultrasonic transducer of 0 kHz or more is installed adjacent to the counter electrode or at a position facing the counter electrode via a material to be plated. 3. A metal strip in which a material to be plated moves with respect to a plating solution, and a counter electrode and an ultrasonic transducer are provided on a front surface and / or a back surface side thereof, and the counter electrode and the ultrasonic transducer are provided with respect to the metal strip. In the electroplating process that is installed in parallel with a certain distance from the metal strip surface, in the vertical plane that is orthogonal to the vertical plane parallel to the moving direction of the plated metal strip, or in the moving direction of the plated metal strip. The electroplating apparatus according to claim 2, wherein an angle formed by the lower surface of the metal band to be plated and the horizontal surface is 5 degrees or more in the parallel vertical planes.