JPH046799B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrolytic cell for wire electroplating that enables electroplating operations at high current density and low electrolytic voltage.

[Prior Art] Conventionally, when electroplating a wire, an electrolytic cell as shown in FIG. 7, for example, has been used. That is, the electrolytic plating solution (hereinafter referred to as electrolytic solution) L drawn out from the tank 1 by the pump P is injected into the electrolytic cell 2 from above, not only to fill the electrolytic cell 2 but also to actively inject a large amount to cause overflow. , the overflow is returned to tank 1. The anode 3 is immersed in the electrolytic solution La in the electrolytic cell 2, and the wire W is electroplated by passing it through the electrolytic cell 2 while contacting the roller (cathode) 4. are giving.

By the way, in order to perform electroplating operations efficiently and economically using such an electrolytic cell for wire electroplating, it is necessary to set the electrolytic conditions to high current density (improvement of electrolysis speed) and low electrolysis voltage (reduction of power cost). )
It is necessary to do so.

However, when the current density during electrolysis is increased to exceed a certain value (this value is called the maximum electrolytic current density), the plated surface of the wire becomes blackish with no metallic luster (this is called a burning phenomenon). Therefore, it is not possible to increase the electrolytic current density unnecessarily, and therefore the efficiency improvement of plating operations has currently reached a plateau. It is believed that the cause of the burnt development described above is a lack of plating metal ions in the vicinity of the wire plating surface.

On the other hand, regarding the decrease in electrolytic voltage, it is necessary to consider the structure of the electrolytic voltage. That is, the electrolytic voltages are 1: anodic decomposition voltage V ₁ , 2: cathodic decomposition voltage V ₂ , 3: voltage due to the specific resistance of the wire material V ₃ , 4: voltage due to the resistance of the plating liquid
V ₄ , corresponds to the sum of the voltage V ₅ due to the 5 circuit resistance and the cutoff resistance voltage V ₆ due to the gas generated at the 6 anodes, so if the voltage of some or all of the components is lowered, the sum of them can be reduced. It is considered that the electrolytic voltage can be reduced. However, among the above, the anodic decomposition voltage V ₁ and the cathodic decomposition voltage V ₂ are voltages for carrying out the electrolytic reaction shown by the following formula (1), and are theoretically constant.

M-SO ₄ +H ₂ O→M+1/2O ₂ +H ₂ SO ₄ ...(1) M: Plating metal element Also, the voltage _V3 due to the specific resistance of the wire is the material of the wire,
The voltage is determined by the thickness and length and must be considered constant during operation. Furthermore
V ₅ is a value that can be ignored in a practical machine. Therefore, it is necessary to reduce the voltage V ₄ due to the resistance of the plating liquid and the cutoff resistance voltage V ₆ due to the gas.
Among these, the gas-induced cutoff resistance voltage V ₆ is the voltage generated when O ₂ generated according to the reaction shown in equation (1) above adheres and accumulates on the anode surface, and its value accounts for a considerable proportion. , there seems to be a lot of room for improvement. Therefore, in order to reduce the electrolysis voltage, it is considered to be promising to reduce the gas-induced cutoff resistance voltage by some means. Note that the voltage V ₄ due to the resistance of the plating liquid is almost determined by the scale of the electrolytic cell, so it cannot be expected to have the same reduction effect as the cutoff resistance voltage V ₆ due to gas.

[Problems to be Solved by the Invention] The present invention has been made in view of these circumstances, and improves electrolytic plating by increasing the electrolytic density by solving the deficiency of plating metal ions near the wire plating surface. An electrolytic cell that can improve efficiency and reduce electric power costs by reducing electrolysis voltage by reducing the gas cutoff resistance voltage value, and which also ensures the sealing performance of the wire passage hole. This is what we are trying to provide.

[Means for Solving the Problems] The electrolytic cell of the present invention that achieves the above object is such that an electrolytic solution injection guide is provided at least on one end side of a cylindrical anode body having a through hole for passing a wire, and the electrolytic solution is The injection guide is provided with a spiral guide plate that introduces the electrolytic solution supplied from a direction intersecting the running trajectory of the wire into the through hole in a swirling flow, and a spiral guide plate is provided on the other end side or approximately the center of the cylindrical anode body. An electrolyte discharge guide is provided in the section, and the electrolyte discharge guide has a built-in rotor equipped with a helical blade that discharges the electrolyte in a direction intersecting the wire passing trajectory, and an electrolyte discharge guide is provided in the shaft portion of the rotor. The gist is that the corresponding wire passing hole is formed with a spiral groove in a direction opposite to the helical rotation direction of the rotor.

[Operations and Examples] The present inventors believe that in order to enable high current density operation and power failure voltage operation, it is desirable to increase the passage speed of the electrolyte in the area where the coated wire and the anode are immersed. With this in mind, I began research. However, in conventional open type electrolytic cells, it is not possible to increase the electrolyte passing rate. In other words, in the case of an open type, in order to increase the electrolyte passage speed, it is necessary to considerably increase the height of the electrolytic cell tank above the overflow part to increase the liquid pressure in the overflow part. need to be made on a considerably large scale, which poses a practical problem. Furthermore, the speed can be increased only in the vicinity of the overflow portion, and it is not necessarily possible to effectively increase the flow speed in all parts. Therefore, in the present invention, a basic configuration is adopted in which the anode body is formed into a cylindrical shape, and the wire passing through hole (closed system) of the cylindrical anode body is used as an electrolyte flow part, and at least one end of the cylindrical anode body is An electrolyte injection guide is provided at the cylindrical anode body, and an electrolyte discharge guide is provided at the other end or approximately at the center of the cylindrical anode body, so that the electrolyte is forced to flow from one end to the other end or from both ends to the center within the wire passage through hole. It is configured so that it flows to That is, by enabling forced flow of the electrolyte, the passage speed of the electrolyte can be dramatically increased, and these means are the same as those described in 2 above.
It has become a common and mutually complementary means of solving two problems. In other words, by increasing the electrolyte flow rate, the electrolyte near the wire plating surface [the electrolyte whose metal ion concentration has decreased due to electrolytic plating] is washed away, and a new electrolyte with a high metal ion concentration is supplied. This allowed the plating reaction to proceed efficiently and prevent burnt development even at high current densities. In addition, by increasing the flow rate of the electrolyte, the O ₂ gas remaining on the anode surface is flushed away, and by bringing the electrolyte into sufficient contact with the anode surface, the gas cutoff resistance voltage is reduced, and electrolytic plating can be achieved even at low electrolytic voltages. It became possible for the reaction to proceed sufficiently.

There are no particular restrictions on the shape of the cylindrical anode;
It may be either circular or polygonal.

FIG. 1 is an explanatory cross-sectional view showing an electrolytic cell according to the present invention, and the electrolytic cell 2a has a shape shown in FIG. An electrolyte introduction guide 6 (details will be described later) is provided, and a fifth
It is constructed by providing an electrolyte discharge guide 8 (details will be described later) having the shape shown in the figure. A supply line 9 is connected to the electrolyte introduction guide 6, and an electrolyte discharge line 10 is connected to the electrolyte discharge guide 8.
is connected. Then, the wire W is introduced into the electrolytic cell 2a from the electrolyte discharge side while being held between the cathode rollers 4, passed through the through hole 5 of the cylindrical anode body 3a, and extracted from the electrolyte introduction side. A porous insulating plate 7 is attached to the inner circumferential wall of the cylindrical anode body 3a for the purpose of preventing short circuit with the wire W.

When plating the wire W using such an electrolytic cell 2a, the electrolytic solution extracted from the tank 1 by the pump P is passed through the supply line 9 from the electrolytic solution introduction guide 6 into the cylindrical anode body 3a. The electrolyte is forcibly introduced into the tank 1 via the electrolyte discharge guide 8 and the discharge line 10. On the other hand, an electrolytic voltage is applied between the cylindrical anode body 3a and the cathode roller 4, and the wire W is run from left to right in the figure. This increases the efficiency of supplying the electrolyte to the wire surface, particularly the efficiency of supplying plating metal ions, and avoids a situation where the plating metal ions become depleted. As a result, electrolytic plating with high current density becomes possible, and electrolytic plating can be completed in a short time. In addition, O ₂ remains on the inner surface of the wire passing through hole 5 of the cylindrical anode body 3a.
is washed away by the electrolyte flow, and the inner surface of the cylindrical anode body 3a is exposed without being encapsulated in O ₂ , so the cutoff resistance voltage due to O ₂ gas can be small, and electrolytic plating can be performed at a low electrolytic voltage. be able to.

However, in the above-mentioned electrolytic cell, there is a concern about liquid leakage from the wire passage hole. Therefore, in the present invention, an electrolytic solution introduction guide is provided which introduces the electrolytic solution supplied from a direction intersecting the running trajectory of the wire into the through hole in a swirling flow, and the electrolytic solution is caused to intersect with the running trajectory of the wire. An electrolyte discharge guide is provided to discharge the electrolyte in the direction to prevent electrolyte leakage.

FIG. 2 is a schematic explanatory diagram showing a typical example of the electrolyte introduction guide according to the present invention. The electrolyte introduction guide 6 includes an introduction member 13, an adapter 14, and a cover plate 24.
The introduction member 13 is provided with a plurality of spiral guide plates 12 on the distal end surface of the stepped cylindrical body 11, and the adapter 14 is provided with an introduction member storage hole 15a in the large diameter portion 14b of the stepped cylindrical body. The supply line 9 is connected to the storage hole 15a in communication with the storage hole 15a, and the small diameter portion 14a is
As shown in the cross-sectional view taken along the line (-) in the figure, a radial rectifier plate 16 is provided for the wire passage tube portion 21. Furthermore, the lid plate 24 has a wire passing hole 22 formed in the center of the dish-shaped disk. When attaching such an electrolyte introduction guide 6 to the cylindrical anode body 3a, first insert the small diameter portion 14a of the adapter 14 into the enlarged diameter hole 5a at the end of the cylindrical anode body 3a, and then The introduction member 13 is stored in the introduction member storage hole 15a of the adapter 14 in the direction shown in the figure, and then the cover plate 24 is fitted so as to be opposed to the end surface of the large diameter portion 14b of the adapter 14.

When the electrolyte L is injected from the supply line 9 at the attachment part of the electrolyte introduction guide 6 configured as described above, the electrolyte flows between the small diameter cylindrical part 11a of the introduction member 13 and the inner wall of the storage hole part 15a of the adapter 14. Then, it flows toward the cylindrical anode body 3a, is guided by the spiral guide plate 12, and flows toward the center. At this time, swirling properties are imparted to the electrolyte flow, and the liquid is pressed toward the outer circumferential side by centrifugal force. The flow then enters the through hole 15 of the small diameter portion 14a of the adapter, and is rectified by the rectifying plate 15 while maintaining the state of being pressed toward the outer circumferential side as described above due to inertial force, resulting in a hollow rectilinear flow. The flow is constricted at the tapered diameter-reduced portion 3b that moves from the cylindrical anode body 3a to the through hole 5 of the cylindrical anode body 3a.
will be introduced to

The electrolyte introduction guide 6 is configured as described above, and the introduced electrolyte flows toward the cylindrical anode body 3a while being pressed against the outer periphery, so that the electrolyte is prevented from flowing into the center through which the wire passes. Leakage of electrolyte on the insertion side is prevented. Moreover, the air in the center of the hollow flow is squeezed in the throttle part and pushed back to the opposite side of the flow direction of the liquid, so there is no chance of air being dragged into the introduced electrolyte, and there is no risk of increased gas cutoff resistance due to air entrainment. .
Examples of other electrolyte introduction guides include a guide in which a spiral 17 attached to the tip of an introduction member 13a is inserted into the small diameter portion 14a of the adapter 14 as shown in FIG. By using , the same effect as above can be obtained.

FIG. 5 is a schematic explanatory diagram showing a typical example of the electrolyte discharge guide according to the present invention. The electrolytic discharge guide 8
The rotor 22 has a built-in rotor 22 having a helical blade 21, and is configured by forming a helical groove 23 in a direction opposite to the rotational direction in a wire passing hole in a portion corresponding to the shaft portion of the rotor 22.
By using the electrolyte discharge guide 8, the electrolyte that is supplied through the through hole 5 of the cylindrical anode body 3a is distributed to the centrifugal side by the rotor 22, which rotates due to the flow. It is collected in a discharge line 10 and returned to a tank (not shown). At this time, liquid leakage in the electrolyte discharge guide 8 is avoided by the distribution effect of the centrifugal force and the pushing back effect of the reverse spiral groove 23.

FIG. 6 is a cross-sectional explanatory view showing an electrolytic cell according to another embodiment 1, in which electrolytic solution introduction guides 6 are provided at both ends of the cylindrical anode body 3a, and the electrolytic solution extracted from the pump P is introduced from both ends into the cylindrical anode body 3a. Through hole 5 of shaped anode body 3a
The electrolyte is introduced into the tank 1, and the electrolyte is extracted from an electrolyte discharge guide 8a provided approximately at the center of the cylindrical anode body 3a and returned to the tank 1.

Effects similar to those described above can be obtained in the electrolytic cell described above.

[Effects of the Invention] The present invention is configured as described above, and since the maximum electrolytic current density can be increased, wire rods can be electrolytically plated efficiently in a short time. Furthermore, since electrolytic plating can be performed at a low electrolytic voltage, power consumption can be reduced. Furthermore, since the wire passage hole is sealed well, there is no risk of liquid leakage.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing an electrolytic cell according to the present invention, FIG. 2 is a perspective explanatory diagram showing an electrolyte introduction guide, FIG. 3 is a cross-sectional view taken along the line - in FIG. 2, and FIG. Figure 5 is a cross-sectional diagram showing an electrolyte discharge guide, Figure 6 is a schematic diagram showing another electrolytic cell, and Figure 7 is a schematic diagram showing a conventional electrolytic cell. It is an explanatory diagram. 1... Tank, 2, 2a... Electrolytic cell, 3a...
... Cylindrical anode body, 4 ... Cathode roller, 5 ... Wire passing through hole, 6 ... Electrolyte introduction guide, 8 ... Electrolyte discharge guide, 9 ... Supply line, 10 ... Discharge line, W ... …wire.

Claims (1)

[Claims] 1. An electrolyte injection guide is provided on at least one end side of the cylindrical anode body having a through hole for passing the wire, and the electrolyte injection guide is supplied with an electrolyte supplied from a direction intersecting the traveling locus of the wire through the through hole. In addition to providing a spiral guide plate to introduce the swirling flow into the interior,
An electrolyte discharge guide is provided on the other end side or approximately in the center of the cylindrical anode body, and the electrolyte discharge guide is equipped with a rotating spiral blade that discharges the electrolyte in a direction intersecting the wire passing trajectory. Electrolytic electroplating for wire rods, characterized in that the wire rod passage hole corresponding to the shaft portion of the rotor is formed with a spiral groove in a direction opposite to the helical rotation direction of the rotor. cell.