JPH0149797B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a liquid flow plating method, particularly to a method for high-speed plating of striped plating strips. [Prior Art] Conventionally, in the case of full-surface plating or stripe-like partial plating of strip-shaped conductors, etc., there have been methods in which the object to be plated is immersed and run through a plating tank, or a method in which a liquid is slightly jetted is applied. Although a method of plating with a hand has been used, there is still a limit to the improvement of the plating speed.
When the plating current density is increased in order to increase the plating speed, there is a limit current density at which the plating quality deteriorates and becomes unpractical when it exceeds a certain value. One way to improve this limiting current density is to spray the plating liquid onto the surface to be plated at high speed and stir it, but if the plated surface is larger than a certain extent, it is necessary to uniformly stir the plating liquid over the entire surface. This may result in uneven plating or partial quality defects. In particular, for full-surface plating of strip-shaped conductors or striped partial plating, in order to improve the stirring effect of the plating solution in the solution, a nozzle with a fixed shape is generally used, as shown in Figure 4. A method has been adopted in which the plating liquid is injected onto the object to be plated 15 through holes (for example, holes 5 formed at a constant pitch in the longitudinal direction of the pipe 4). According to this injection method, the limiting current density can be increased because a stirring effect is obtained in the areas that are directly hit by the plating liquid, but when looking at the width direction of the object to be plated, there are areas that are hit by the jet and areas that are not hit by the jet. Differences may easily occur, and stirring tends to be uneven. Therefore, there is a strong need for the development of high-speed plating that can uniformly stir the plating liquid over the entire surface even if the plating area is increased, and that can improve the critical current density without causing uneven plating. As a high-speed plating method capable of solving these problems, the present applicant has proposed a liquid flow plating method (patent application No. 118682, filed on June 8, 1982).
No.) was filed. Since this plating method uses a liquid flow down method, even if the plating area is large, the plating liquid can be uniformly stirred over the entire surface in the width direction of the strip.
Although this is an effective plating method that can improve the critical current density without causing uneven plating, it also has the following problems. That is, in order to obtain a high-speed plating liquid flow with the liquid flow method, it is necessary to have a large head difference, so the structure of the plating tank is larger than that in the conventional dipping method, and the amount of plating liquid increases. In addition, when the plating liquid flow rate increases, air entrainment from the upper plating tank liquid level increases, which has the disadvantage that it tends to deteriorate the plating liquid and adversely affect the plating quality. Therefore, in order to obtain a high current density, There was still a limit to the flow velocity. [Problems to be Solved by the Invention] An object of the present invention is to provide a novel liquid flow plating method that can eliminate the drawbacks of the prior art described above and increase the speed of plating. [Means for Solving the Problems] The present invention provides that when plating is performed by arranging the object to be plated in a liquid pipe line in a plating tank formed by a wall surface, the liquid pipe line Plating is carried out by injecting a synthetic plating liquid flow, which is a plating liquid flow in the axial direction and a plating liquid flow in a direction substantially perpendicular to the axial direction, onto the object to be plated. A liquid flow plating method is provided. Here, in the liquid flow plating method, the object to be plated is a belt-like body that moves in the longitudinal direction of the object to be plated in the liquid pipe path while maintaining its wide side in a substantially vertical state. It is preferable that there be. [Structure of the Invention] A preferred embodiment of the liquid flow plating method of the present invention shown in the drawings will be described in detail. The apparatus for carrying out the liquid flow plating method of the present invention includes a liquid pipe line 18 configured by a flow passage wall 3 installed in a first plating tank 1.
Equipped with. A plating liquid injection hole 5 is installed on the wall surface and/or near the wall surface of the flow path wall 3 of this liquid pipe path 18 . The plating liquid injection hole 5 may be a jet hole 5 formed in the side wall of the injection pipe 4 as shown in FIG. The injection holes may be provided in the pipe 4 and the flow path wall 3 at the same time. It may be of any type as long as it can realize the jet flow 9 described later. In order to perform high-speed plating, it is important to violently stir the plating solution on the plating surface, especially in the partial plating section 17 as shown in FIG. 3, to thin the diffusion layer on the plating surface. become. Conventionally, as shown in FIG. 4, the object to be plated 15 held in the plating tank 1 is sprayed from the injection hole 5 of the plating liquid injection pipe 4 installed in the plating tank 1. A stirring method in which the plating liquid is sprayed has been used, but in this stirring method, the stirring force is easily dispersed in the liquid, making it difficult to obtain a sufficient stirring effect necessary for high-speed plating. In the present invention, the liquid pipe line 18 is configured by the flow passage wall 3 provided in the first plating tank 1, and the stirring flow 8 at a constant pressure is supplied into the liquid pipe line 18 from the bottom of the liquid pipe line, and the flow is simultaneously A plating liquid injection hole 5 is provided in the vicinity of the channel wall 3 and/or the channel wall 3, and a jet stream 9 is provided in the vicinity of the channel wall 3 and/or the channel wall 3.
A plating liquid stream 10 is created by combining the stirring stream 8 and the jet stream 9, and the object to be plated 15 is exposed to the plating liquid stream 10 to improve the plating speed. FIG. 2 shows a schematic diagram of the first plating tank shown in FIG. 1, but as shown in FIG. Alternatively, a liquid conduit 18 as shown in FIG. 1 may be used. After plating, the synthesized plating liquid flow 10 flows out from the plating liquid outlet 12 provided in the first plating tank. A plating tank 2 is provided, and the plating liquid is caused to overflow from the plating liquid outlet 12 provided in the first plating tank to the second plating tank 2.
It is preferable to pool the plating liquid in the plating tank 2, to communicate the bottom of the second plating tank 2 and the bottom of the first plating tank through a pipe line 11, and to provide a pump in the pipe line 11 to circulate the plating liquid. The stirring flow 8 is passed from the bottom of the second plating tank to the pump 7.
The injected liquid 9 is supplied to the liquid pipe line 18 through the second
It is supplied from the bottom of the plating tank through a flow path (not shown) to the injection pipe 4 via a pump. FIG. 3 is a sectional view of the plated object 15. As shown in FIG. The coated material 15 as shown in FIG.
It is a belt-shaped body that moves in the longitudinal direction while maintaining its wide side in a nearly vertical state, and this belt-shaped body is
The effect of the present invention is remarkable when pinning is performed while traveling perpendicularly to the plane of the drawing. Figure 3 shows masking tape 1 for partial plating where two strips are plated at the same time.
Although the partially covered appearance is shown in 6, any form of partial plating may be used, and the plated object 15 is not limited to a band-like object, but may be a linear object or a lump-like object. Good too. [Example] Next, an example of the liquid flow plating method of the present invention will be described based on specific implementation conditions. A strip having the cross-sectional shape shown in FIG. 3 was used as the plated object 15, and after pretreatment, two strips were partially silvered on one side at the same time using masking tape 16 shown in the same figure. The dimensions and shape of the strip are 65mm wide.
The thickness is 0.5mm, and the striped part plating part 1
The width of No. 7 is 8 mm at the top and bottom. The plating conditions are AgCN80g/, KCN100 as plating liquid.
Plating was carried out using a silver cyanide plating solution of 1.5 g/g at a solution temperature of 25.degree. C. so that the thickness of the silver plating was 1 .mu.m. Here, as Comparative Example 1, plating was carried out under the same conditions as above, except that in this case, as shown in FIG. 4, the plating liquid injection pipe 4 was used, and the Plated product 15
Set the plating liquid flow rate near the plating surface to 1.0 to 1.2.
m/sec. Furthermore, as Comparative Example 2, plating was performed under the same conditions as above. However, in this case, in FIG.
The flow rate of the plating liquid in the chamber was 1.0 to 1.2 m/sec. Now, in this example, in addition to the above-mentioned conditions, the plating liquid injection pipe used in Comparative Examples 1 and 2 (plating liquid flow rate 1.0 to 1.2 m/sec near the plating surface) and the liquid pipe line Plating was carried out in the apparatus shown in FIG. 1 using both No. 18 (plating liquid flow rate 1.0 to 1.2 m/sec). The results are shown in Table 1.

[Table] As is clear from Table 1, the plating method of this example has a higher current density than Comparative Examples 1 and 2.
No unevenness or burning occurs up to 30A/ ^dm2 ,
It can be seen that it is well plated. It can also be seen that the variation in the plating thickness is smaller than in Comparative Examples 1 and 2, and the plating liquid is uniformly stirred in the vicinity of the plating surface. [Effects of the Invention] In the liquid flow plating method of the present invention, plating is performed within the plating flow in both directions, the jet flow and the agitation flow, which are substantially perpendicular to each other. Plating current density is improved without causing uneven plating. Since the flow is directed in both directions, the plating speed can be improved compared to a single stirring flow. In addition, in the liquid flow type using the plating liquid level head difference,
As the flow rate increases, more air is drawn in from the liquid surface, which tends to cause deterioration of the plating liquid, generation of gas, uneven plating, etc. According to the formula plating method, these drawbacks can be eliminated and the plating work can be stabilized.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the liquid flow down plating method of the present invention. FIG. 2 is a sectional view showing another embodiment of the first plating tank. FIG. 3 is a sectional view of the coated product. FIG. 4 is a sectional view of a conventional plating method. 1: first plating tank, 2: second plating tank, 3: channel wall, 4: injection pipe, 5: plating liquid injection hole,
6: Plating liquid, 7: Pump, 8: Stirring flow, 9: Jet flow, 19: Plating liquid flow, 11: Pipe line, 12: Plating liquid outlet, 13: Anode electrode, 14: Container for jet flow , 15: Plated product, 16: Masking tape, 17: Partially plated portion, 18: Liquid pipe line.

Claims (1)

[Scope of Claims] 1. When plating is performed by placing the object to be plated in a liquid pipe line in a plating tank formed by a wall surface, plating in the axial direction of the liquid pipe line is performed. A liquid flow plating method characterized in that plating is performed by injecting a synthetic plating liquid flow of a liquid flow and a plating liquid flow in a direction substantially perpendicular to the axial direction onto the object to be plated. . 2. The object to be plated is a belt-shaped object that moves in the longitudinal direction of the object to be plated in the liquid pipe while maintaining its wide side in a substantially vertical state. Liquid flow plating method.