JPS61270386A - Method for supplying copper ion to copper sulfate plating bath - Google Patents

Abstract

PURPOSE:To enable the use of an insoluble electrode and to eliminate the stop of a plating line by the exchange of an electrode by combinedly supplying copper oxide and copper sulfate to a copper sulfate plating bath. CONSTITUTION:A copper sulfate plating bath L filled into a plating tank 11 is allowed to overflow the tank 11, all of the bath is recovered in a storage tank 16, and the bath is circulated to the tank 11 with a pump 15. A long-sized beltlike material S to be plated is horizontally fed into the space between electrodes 13, 14 placed horizontally at the upper part of the tank 11. The material S is plated with copper in the copper sulfate plating bath L contg. about 200g/l copper sulfate and about 50g/l sulfuric acid while copper oxide and copper sulfate are supplied to the bath in 3:1 weight ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for replenishing copper ions to a copper sulfate plating bath.

[Conventional technology and its problems]

Copper plating is rarely used alone for corrosion protection or decoration because copper easily discolors in the air, but copper plating has good adhesion to metals such as nickel.
Widely used for intermediate plating. Copper plating is also sometimes used to prevent carburization.

When performing such copper plating, a copper sulfate plating bath has been used for a long time, but when copper plating is continuously applied to a long strip wave plated material such as a long steel strip using the copper sulfate plating bath, , copper sulfate (Cu SOa ・5 H2O): 15
0-250g/6, sulfuric acid (HZ SC2): 50-75
g//! A copper sulfate plating bath having a basic bath composition of The copper film is formed on the surface of the long band wave plated material using electrolytic electrodeposition.

By the way, regarding how to replenish copper ions to the above-mentioned copper sulfate plating bath, it has conventionally been usual to use a copper electrode as a dissolving electrode and to melt the copper electrode to replenish copper ions.

To give a specific example, the plating equipment as shown in FIG. 4, that is, the copper sulfate plating bath (41) stored in the plating tank (41)
Zinc roll (42) is immersed in L), and the long band wave plating material (S) is guided into the copper sulfate plating bath (L) by the zinc roll (42).
S) is fed in the vertical direction as shown by the arrow mark)) is used, and equipment is used in which copper electrodes (43) are suspended so as to be lined up in parallel. ...(43) to remove copper ions from copper sulfate plating bath (L)
They were resupplying inside. In addition, (44) (44
) is a conductor roll for supplying power to the long strip wave plated material (S).

When performing copper plating using such equipment, a copper electrode (43
)...(43) can be easily moved upward or horizontally, so the copper electrode (43) serving as the melting electrode...(
43) has the advantage of being easy to replace, but the copper sulfate plating bath (L) from the bearing part of the zinc roll (42)
leakage becomes a problem. In addition, long strip wave plated material (S)
The feeding method in which the feeding direction is changed in the copper sulfate plating bath (L) has the problem that the long band wave plated material (S) follows a complicated path, resulting in poor rootability. .

Therefore, in order to solve this problem, as shown in Fig. 1 (longitudinal cross-sectional view) and Fig. 2 (cross-sectional view taken along line nn in Fig. 1), we developed a long band-shaped wave plated material (S). A plating equipment that feeds horizontally is being considered.In other words, a plating tank (
11) The copper sulfate plating bath (L) filled in the interior overflows from the upper layer thereof to the upper layer of the copper sulfate plating bath (L),
Electricity is supplied from the conductor roll (12) (12) to feed the long band wave plated material (S) which becomes the cathode in the horizontal direction so that the long band wave plated material (S) is lined up and down in parallel. Equipment in which electrodes (13) and (14) serving as cathodes are arranged horizontally is used. In addition, the plating tank (
The copper sulfate plating bath (L) overflowing from 11) is collected in its entirety in a storage tank (16), and is circulated and supplied to the plating tank (11) by a pump (15) attached to the storage tank (16). It looks like this.

When such plating equipment is used and dissolving electrodes are used as the electrodes (13) and (14), leakage of the copper sulfate plating bath (L) is eliminated and the root permeability of the long strip wave plated material (S) is improved. The work of replacing the electrode (14) horizontally arranged below the long band wave plated material (S) becomes extremely troublesome work. That is, in order to replace the electrode (14), the feeding of the long strip wave plating material (S) is stopped, and the state in which the long strip wave plating material (S) is not present above the electrode (14) is changed. It is necessary to replace the electrode (14) after the electrode (14) has been replaced, which also causes a decrease in productivity.

Moreover, there is a problem that the copper ion concentration in the copper sulfate plating bath (L) tends to change due to the relationship between cathode efficiency and anode efficiency, and it is extremely difficult to control it, and it is also necessary to constantly replenish sulfuric acid.

Therefore, as the electrodes (13) and (14), we used an insoluble electrode with a platinum plating layer of about 2 μm formed on the surface of a base material mainly composed of titanium, or an insoluble electrode with a noble metal oxide baked on, and the dissolving electrode as described above. It is being considered to solve the problem when using .

However, if the method of replenishing copper ions into the copper sulfate plating bath (L) by dissolving the electrodes (13) (14) is not adopted, there is a method of replenishing copper ions into the copper sulfate plating bath (L). It is necessary to think about this in a new way, but to date, no suitable method of replenishment has been devised.

The present invention has been made in view of the above circumstances, and aims to make the electrodes (13) and (14) insoluble by devising a new method for replenishing copper ions into the copper sulfate plating bath (L). be.

[Means for solving problems]

The method for replenishing copper ions in a copper sulfate plating bath according to the present invention includes oxidation &Pl (CaO) and sulfuric acid ipJ (Cu S 04
・5H20) is unique in that it can be supplied in combination with

The reason why we decided to replenish copper oxide and copper sulfate in combination was that if we were to replenish only copper oxide, the cost would be high and we would need to replenish sulfuric acid as usual. This is because if only copper sulfate is supplied, the sulfuric acid concentration in the copper sulfate plating bath will increase and the bath balance will be disrupted.

[Effect]

When such a copper ion replenishment method is adopted and continuous copper plating is applied to a long strip wave plated material such as a long steel strip, copper ions can be appropriately replenished into the copper sulfate plating bath without using a dissolving electrode. Then, appropriate copper plating is applied to the long strip wave plated material.

Moreover, since the electrode becomes an insoluble electrode, there is no need to constantly replace the electrode, and there is no need to stop feeding the long strip wave plating material for electrode replacement.

[Example] Using the equipment shown in Figures 1 and 2, a plating tank (I
The copper sulfate plating bath (L) filled in the tank I) is allowed to overflow from its upper layer, and the overflowing copper sulfate plating bath (L) is collected in its entirety in a storage tank (16) and then transferred to a pump (15).
) to the plating tank (11), and the long strip wave plating material is passed between the electrodes (13) and (14) horizontally arranged on the upper layer of the copper sulfate plating bath (L) in the plating tank (11). By feeding (S) in the horizontal direction, copper plating was applied to the long strip-shaped material to be plated (S).

The intended bath composition of the copper sulfate plating bath (L) is copper sulfate: 20
0 g/β, sulfuric acid: 50 g/l, and copper oxide and copper sulfate were added to the copper sulfate plating bath (L) at a ratio of 3:1 (
It was replenished at a ratio of (weight ratio).

In addition, as the electrodes (13) and (14), 470 Dragon
Two insoluble electrodes were used in which a layer of baked noble metal oxide or a 2 μm platinum plating layer was formed on the surface of titanium of 700 HX IQm.

As a result of continuous operation for 100 days,
Appropriate copper plating was applied to the long strip wave plated material (S), and there was no need to replace the electrodes (13) (14).

In addition, the temperature of copper oxide to be supplied to the copper sulfate plating bath (L) is 20°C.
Figure 3 shows the results of examining the solubility curves at (*) and 40°C (○), and it can be seen that the solubility is higher when heated to 40°C (than at room temperature). Therefore, in plating operations that are normally carried out by heating the copper sulfate plating bath (L) to 30°C, copper oxide is used in the copper sulfate plating bath (L).
It can be seen that it is convenient because it can be easily solved.

Further, a method of using copper hydroxide or cuprous oxide instead of copper oxide is also considered.

(Effects of the Invention) As described above, by using the method of the present invention, copper ions can be appropriately replenished into the copper sulfate plating bath without dissolving the electrode and replenishing copper ions into the copper sulfate plating bath. The electrode can be an insoluble electrode, and even when the material to be plated is fed horizontally, there is no need to stop the line to replace the electrode, which prevents productivity loss due to line stoppage. can.

[Brief explanation of the drawings] Fig. 1 is a vertical cross-sectional view schematically showing a plating equipment that feeds a long strip wave plating material in the horizontal direction, and Fig. 2 is a vertical cross-sectional view schematically showing the plating equipment that feeds long strip wave plating materials in the horizontal direction.
3 is a graph showing a solubility curve of copper oxide, and FIG. 4 is a longitudinal sectional view schematically showing a plating equipment that feeds a long band wave plating material in the vertical direction. IL41: Plating tank, 13, 14, 43: Electrode,
16: storage tank, 42 herring roll, L: copper sulfate plating bath, S: long strip wave plating material.

Claims (1)

[Claims] (1) A method for replenishing copper ions to a copper sulfate plating bath, which comprises replenishing copper oxide and copper sulfate in combination.