JPS63118094A - Electroplating equipment - Google Patents

Abstract

PURPOSE:To improve the productivity in plating by providing an anode having small through holes on its strip surface and an ultrasonic vibrator to increase the plating current density when a metal is plated on the surface of the traveling metallic strip. CONSTITUTION:A current is passed at a high current density between an anode 3 and long-sized metallic strip 11 which is made into a cathode by a conductor roll 4 and travels in a plating bath 2, and the strip is plated at a high plating rate. In this case, since the plating metal ion concn. in the plating soln. in the vicinity of the surface of the metallic strip 1 is rapidly decreased, the plating soln. is injected onto the strip surface from a plating soln. nozzle 5 to replenish the ion, a vibrating plate 7 provided with ultrasonic vibrators 8 at regular intervals is arranged on the side of the anode 3 opposite to the strip 1, and many slits 9 having an inclined face 10 are provided in the anode 3. The decrease of the metal ion concn. in the plating soln. on the surface of the strip 1 is prevented by the diffusion due to the injection of the plating soln. and ultrasonic vibration, and a plated layer without any pit is formed at a high rate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electroplating apparatus, and more particularly to an electroplating apparatus M for surface treatment of a strip (such as a steel plate base material).

[Conventional technology and its problems]

As shown in 12.1, one of the plating conditions is 7! ! It is desirable that the flow density be as high as possible. That is, (1
) Increases plating speed, (2) Increases hydrogen overvoltage to efficiently plate base metals, (3) Creates a dense and strong plating film, and (4) Improves uniform electrodeposition. be done. However, the upper limit of usable current density is determined by the amount of metal ions near the bridge, so in other words, the higher the current density, the more 787pi gold ions
, cannot be sufficiently diffused to the plated surface, and the metal ion concentration on the plated surface decreases. Therefore, in order to reduce the size of this diffusion layer, 11 is considered to be an effective means for increasing the current density, and is also effective in preventing bit generation.

By the way, as such stirring means, conventional methods include (al air stirring 1?, (b1 mechanical stirring + 'l' (propeller, cathode rocking), (C1 ultrasonic stirring, fd + forced convection by continuous filtration of the plating solution, etc.). It is well known that, particularly in strip electroplating apparatuses, agitation by forced convection is mainly carried out.

However, if forced convection is to be strengthened to reduce the size of the diffusion layer, the flow rate must be increased and the pump capacity must be increased, and mechanical agitation requires directional or localized agitation. becomes. Further, when ultrasonic stirring is used alone as introduced in Japanese Utility Model Publication No. 12007/1983, when used in a strip electroplating apparatus, the output is increased and the equipment becomes large.

Means for Solving Problems c] Therefore, the present invention was created to solve all of the problems of the prior art at once. In order to contribute to downsizing and labor saving, ultrasonic vibrators are installed at appropriate intervals on the surface of the strip in an electroplating device that electroplates the strip in a plating tank with forced convection of the plating solution. An electroplating device is provided in which a small through hole having an angle that widens toward the cough emitter is formed between the oscillator and the cough emitter, and an anode plate is interposed therebetween.

[For production]

The strip is run through a plating tank with the cathode as a cathode, and the filtered plating solution is spouted into the plating tank to agitate the plating solution in the tank, and the plating is also carried out using ultrasonic waves from an ultrasonic vibrator. Since the liquid is stirred to make the diffusion layer on the strip surface as small as possible, the plating speed can be improved while increasing the current density. In such case,
Since the ultrasonic waves from the ultrasonic wave are blocked by the anode plate, a small hole is drilled in the anode plate so that the ultrasonic wave is transmitted through the small hole and irradiated onto the strip. Because the irradiation of such ultrasonic waves causes localized plating, such as spot patterns, to be formed on the plating surface, in order to prevent this, the ultrasonic waves are reflected on the sloped surface of the small through hole that widens toward the ultrasonic transducer. Stir evenly over the strip surface.

〔Example〕

The details of the structure of the present invention will be explained with reference to embodiments shown in the accompanying drawings. The figure shows a plating apparatus of a continuous electroplating line, where 1 is a strip plating tank and 2 is an electrolytic plating tank, which is a horizontal tank with an open top, which is called a tray type.

3.3 is the upper and lower anode, 4.4 is the front and rear conductor crawl, 5, 5 is the plating solution outlet, and 6, 6 is the plating solution overflow roller.The plating solution that overflowed from the overflow roller 6.6 is , a plating solution outlet 5 is supplied by a pump P via an appropriate ion metal filtration device (not shown).
, 5, the air is blown out between the anodes 3° and 3.
The above structure represents a known plating apparatus for a continuous electroplating line.

Here, in this embodiment, one single-strength plate 7 is provided on the upper anode 3, and a plurality of vibrators 8, 8, . . . are provided on the diaphragm 7 at equal intervals. Therefore, the ultrasonic waves from the vibrator 8 are irradiated perpendicularly to the strip 1 and the anode 3, thereby suppressing the voltage drop due to the splitting action of the strip 1, which is the cathode, and the anode 3. Further, the lower anode 3 has a similar structure.

By the way, in the case of electroplating the strip 1, the frequency 19f of this ultrasonic wave is preferably in the following range.

10KHz ≦"≦1000KHz In other words, below 1KHz, the stirring effect is small, ]0
At OOKHz or higher, cavitation erosion occurs, resulting in a spotted corrosion pattern. The parallel number f is f~1°05f, and is continuously modulated by changing the voltage of the ultrasonic generator. This is because when ultrasonic waves are applied at a constant frequency f, the stirring effect is maximum at the peak of the frequency f, and the effect is small elsewhere.

Next, the distance Md between the vibrator 8 and the strip 1 is important for electrodepositivity, and it has been found that this can be determined as follows. That is, due to this distance d, the stirring force of the ultrasonic wave reaches its maximum at d#1/4λ (2n-1), so that a concentration gradient of the plating metal ions can be found.

However, λ is the wavelength of the ultrasonic wave (λ・f=c, c is the speed of sound) n is a natural number. Therefore, initially, the distance d between the transducer 8 and the strip 1 is
If the plating (metal precipitation) progresses, the distance d at the peak position will no longer match the actual distance due to its thickness. In other words, the thickness of the plating layer differs. Therefore, by changing the voltage of the ultrasonic generator,
The frequency is varied so that even if metal particles are deposited, the effect of ultrasonic waves can be maximized on the surface of the metal particles. Furthermore, since such modulation causes pressure fluctuations in the plating solution, metal ions can be supplied to the strip surface and the diffusion effect can be increased more than when no modulation is used.

Next, the following relationship is established for the distance d° between the surface of the anode 3 and the vibrator 8 to help release the oxygen gas generated on the surface of the insoluble electrode due to the resonance caused by the ultrasonic waves.

d' ヰλ/4 (2n-1) However, λ and n are the same as above.Furthermore, the upper anode 3 is made of a metal material such as stainless steel or copper alloy that has a high ultrasonic reflectance. The shape is formed as shown in FIGS. 1 and 2. The anode 3 is provided with a slit 9, and the slit 9 is connected to the strip l.
The slit 9 is perforated so that the vibrator 8 is located at right angles to the traveling direction of the slit 9 and on the center line of the slit 9. Configure. As a result, since the ultrasonic waves are reflected by the inclined surface 1O, the influence on the plating solution between the positive 8j3 and the strip 1 is expanded by the opening area of the slit 9, and therefore the local Ultrasonic irradiation can be avoided.

In summary, the present invention has the following effects because the configuration described in the claims has been explored.

(Effects of the Invention) According to the present invention, it is possible to improve the plating speed of electroplating, increase productivity, reduce the factory area and save labor, and in particular, electroplating equipment for strips is generally oversized. However, by combining the stirring action of forced convection of the plating solution with the stirring action of ultrasonic waves, it is possible to avoid overscaling of any of these devices and improve the plating speed. A small through hole was drilled into the anode used in the electroplating equipment, and the small through hole was formed at an angle that widened toward the ultrasonic vibrator.
Uniform ultrasonic irradiation eliminates spots (pits) on the plated surface of the strip, improving quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, and FIG. 2 is a perspective view of the main parts. 1... Strip, 2... Electroplating tank, 3...
Anode, 8... vibrator, 9... slit.

Claims (1)

[Claims] In an electroplating apparatus for electroplating a strip in an electroplating bath with forced convection of a plating solution, ultrasonic vibrators are provided at appropriate intervals on the surface of the strip,
An electroplating apparatus characterized in that an anode plate having a small through-hole having an angle that widens toward the transmitter is interposed between the strip and the vibrator.