JPS6230898A - Method and apparatus for replenishing metallic component to plating bath - Google Patents

Abstract

PURPOSE:To maintain the specified concn. of Sn<2+> in an aq. SnSO4 soln. for a long period of time by replenishing FeSO4 to a replenishing tank contg. the aq. SnSO4 for replenishing Sn<2+> to a bronze plating bath or filling an inert gas therein. CONSTITUTION:Sn<2+> ions and Cu<2+> ions are replenished from replenishing tanks 3, 4 into the plating bath 2 consisting of a sulfuric acid bath in a bronze plating tank 1 to execute bronze plating. SnSO4 powder 5 and water 6 are supplied to the tank 3 and are stored therein the form of the aq. SnSO4 soln. in the above-mentioned method. The aq. SnSO4 soln. is continuously or intermittently replenished to the plating bath 2 while the FeSO4 powder is continuously or intermittently replenished to the sq. SnSO4 soln. from an adding device 8 or while the inert gas such as N2 supplied from an inert gas supply device 9 is filled into the tank 3. The oxidation of SnSO4 during the storage is thereby prevented and the specified concn. thereof is maintained, by which the stable plating is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method and an apparatus for replenishing all metal components to a plating bath for bronze plating a needle wire or the like.

(Prior art) Conventionally, in the production of bronze-plated peat wire used for automobile tires, etc., drawn wire material f Sn"
Passed through a sulfuric acid bath containing (divalent tin) ions and Cu'' (divalent copper) ions, and then plated by displacement plating, Cu
- A method of plating the surface of the drawn wire material with a Sn alloy has been adopted.

In this displacement plating method, the inner material of wire drawing is eluted into the plating bath and becomes Fe io/, and the Sn in the plating bath is
'+ and Cu'+ precipitate on the surface of the drawn wire material, and Cu'+
- Sn alloy bronze is plated.

In such a plating process, as the plating process progresses, the concentrations of Sn'+ and Cu'+ ions in the plating bath decrease.
It is necessary to supply ions from outside.

In the conventional technology, when replenishment of Sn'+ is carried out using 5nSOz water and each solution, Sn is oxidized by oxygen in the atmosphere in the replenishment tank and becomes SnO(Sn''+).
In order to prevent the 2+ amount from decreasing, it is supplied intermittently in the form of powder or paste. However, if it is replenished in the form of powder or paste, local concentration differences will occur in the plating bath, resulting in uneven plating on the product, so replenishment in the form of an aqueous solution is desired.

(Object of the invention) This invention was made in view of the above-mentioned circumstances.
When replenishing :)n in the form of SO4 aqueous solution, Sn'
The purpose is to completely prevent white sludge and precipitation caused by + oxidation, maintain the full Sn'+ concentration of the aqueous solution over a long period of time, and completely eliminate the difference in plating bath concentration to obtain beautiful plating.

(Structure of the Invention) The gist of the invention is as follows: (1) SnJ
In the +k replenishment method, 5nSOv is made into a water iW liquid and stored in a replenishment tank, and this 5nSO<z water bath liquid is continuously or intermittently replenished with Fe5Oa, or/and the replenishment tank is A method for replenishing plating metal components, characterized by continuously or intermittently replenishing each SnSO4 water solution into a plating bath while the tank is fully filled with inert gas (a 215nS04I addition device, a water addition device, This is a plating bath metal component replenishment device characterized in that a Sn 2 replenishment tank equipped with a stirrer is provided with an Fe50 & addition device and/or an inert gas supply device.

The present inventors have succeeded in preventing the oxidation reaction of Sn'+ in the SnSO4 water bath solution by the atmosphere and
As a result of various research experiments on how to maintain the total concentration of ions, we found that Fe5O4tf was added to the Sn50g water bath solution as a replenishment solution.
It has been found that the method of adding 5n SOu aqueous solution and the method of sealing the surface of the 5nSOu aqueous solution from the atmosphere with an inert gas such as N gas or M gas are very effective.

FIG. 1 is a diagram showing the time course when 5nSO1 &Sn'+ in the water bath solution changes to 5nOr. Figure 1 (8
) is a comparison of the variation in the amount of Sn when a 50 g Sn water solution was sealed with water bath liquid N cogas and when it was left in the atmosphere. In the figure, curve (a) is the curve for the amount of bn when left in the atmosphere, and the curve (to) is the curve for the surface '(zN
It is a curve of Sn'+ amount when cogas sealed.

As is clear from the figure, in the case of the case left in the atmosphere, it becomes almost zero after 2 days, whereas in the case of the case sealed with N cogas, there is almost no decrease in the amount of Sn'''.

In addition, on the day of Figure 1, Fe5 was added to a 5nSOs aqueous solution in the atmosphere.
The figure shows all the fluctuations in the amount of noodles when 0& is added. Curve (C) in the figure is a curve of SnJ+ amount when 10 ppln is added at Fe'+ concentration, and the curve (dl is the same as 20ppln).
pm, the curve (fEi) is the curve of the Sn'+ amount when the same 100 ppm, and the curve button) is the same 500 ppm.

As is clear from the figure, Fe5Oa = Fe in the water bath liquid
It can be seen that adding 20 to 500 ppm?1 of "ex" is effective in preventing a decrease in Sn"Ji.

It was also confirmed that the combined use of the N,2 gas sealing method and the Fe5o&k addition method is effective in maintaining the total υ,On amount and concentration at a high concentration for a longer period of time.

In this experiment, Fe5O4t was added at the start of the experiment, and the Sn'+ concentration was analyzed by portammetry analysis.

Based on the above experimental results, the present invention provides 5nS
By adding F6+SOa to the O4I water bath solution and/or sealing it with an inert gas, the Sn"J degree can be maintained for a long period of time.
+ component can be replenished in the form of Sn50g f water bath solution, and there is no difference in concentration.

In this invention, the amount of Fe5O4t added is Fe5O4t.
``A concentration in the range of 20 to 500 ppm is preferable. This is because if the added amount is less than 20 ppm, the effect of preventing the Sn concentration from decreasing is small, and if it exceeds 500 ppm, a greater effect cannot be expected, and on the contrary, the Fe J+ concentration increases and the plating efficiency decreases. There is a possibility that such drawbacks may occur.

A more preferable range is 20 to 1100 pp.

Also, this FeSO4 is usually Fe5Oa ・7HJ○ (7
Since it is commercially available in the form of water salt), it is preferable to add it in this form.

(Example) FIG. 2 is a diagram showing an example in which the apparatus of the present invention is applied to a bronze plating peat wire production line. (1) is a plating tank filled with a sulfuric acid plating bath (2) containing Sn'+ ions and Cu'+ ions. The wire to be plated is passed through this plating bath (2) for displacement plating. Plating bath (2) along with plating i (row)
) and Sn1+ ions decrease, so it is necessary to replenish image ions. (3) is Sn
'+ supply tank, and (4) Cu'+ supply tank. The Su'+ supply tank (3), which is an important point of this invention, contains SnS to which powdered 5nSO4tf is added.
An O4 addition device (5), a water addition device (6), and a stirrer (7) are provided, and the added Sn50g and water are turned into an aqueous solution by the stirrer (7). This invention further provides Fe50<
= Addition device (8) or/and inert gas supply device (
9).

In addition, the Cu replenishment tank (4) is equipped with a Cu5Oμ addition device Oa, a water addition device (6), and a stirrer (7), and Cu5Oσ is also replenished in a water bath liquid state.
0g is stable and there is no need for an inert gas seal.

The concentration of the plating bath (2) is controlled by, for example, a plating bath concentration analyzer 01) using a fluorescent X-ray analysis method, and the operation of the entire apparatus is controlled by a computer (2). A signal is sent from the computer α3 to the Sn supply tank (3) and the Cu'+ supply tank (4), and the Snu
+ Supply evening: / To Ri (3) (D SnSO4 powder, Fe
QOu %), the amount of water added, the Nu gas supply 8, and the amount of SnSO4 water bath solution supplied from the Sn'+ supply tank (3) to Metsukito (1) are also controlled.

Furthermore, the amount of Cu5Oa powder and water added to the Cu replenishment tank (4) and the amount of replenishment from the Cu'+ replenishment tank (4) to the plating tank (1) are also controlled.

Next, examples of the method of this invention will be described.

Using this invention device sound as exemplified in FIG. 2, 0.97rxm
Bronze plated peed wire of g was manufactured.

The SnSO4 aqueous solution in the Sn j+ replenishment tank (3) was prepared in an amount equivalent to 7 days' worth of replenishment to the plating tank (1) once every 7 days, and the solution was stored at a Sn'+ concentration of 1000 ppm and 20 ppm.ノFe (5 in Ff9SOg)
4 ppm) t Add Sn' every 12 hours.
+Prevented the decrease of Snu+ in the supply tank (3).

On the other hand, when inert gas sealing was performed, 2.0 g of Nu gas was supplied from the inert gas supply bag @ (9) and Gas Sea JV was performed.

Also, 5nSOv water bath liquid and Cu
The amount of SO4 to be supplied to the plating tank (1) as an aqueous solution is as follows: Sn' + 72 degrees in the plating tank (1) at 500 p'pm;
The Cu′+ concentration was controlled to be 2000 ppm, and continuous replenishment tff was performed.

Figure 3 shows the Sn J+ supply tank (3) when this invention was implemented.
FIG. 2 is a diagram showing a change in the Snj+ concentration in FIG.

As is clear from the figure, Sn in Snj + supply tamper 3)
No decrease in '+ was observed at all.

Also, FIG. 4 shows the change in Sn concentration in the plating tank (1) when this invention is implemented and when the conventional method is implemented. FIG. The curve (G) in the figure is the 3nj+ concentration curve when this invention is implemented,
Curve (3) is the Sn'+ concentration curve when the conventional method is implemented.

As can be seen in the figure, in the past, there was a difference in concentration within the plating tank because it was added intermittently in the form of powder, but with this invention, it can be continuously replenished in the form of a water bath, so there is no difference in concentration within the plating tank. It hasn't happened at all.

(Effects of the Invention) As described above, the present invention provides SnS in the auxiliary tank.
Since the Sn strength of the O4 aqueous solution could be maintained for a long time, no difference in plating bath concentration occurred, and therefore, the plating unevenness of the bronze plated wire was reduced by 5.0%.

[Brief explanation of the drawing]

Figure 1 shows Sn'' 7f): 5n in SnSO4 aqueous solution.
Figure 2 is a diagram showing the time course of change to Ox, Figure 2 is a diagram showing an example of the invention in which the device was applied to a bronze plating peat wire manufacturing fin, and Figure 3 is a diagram showing the time course of the change to Ox.
Fig. 4 is a diagram showing the change in Sn'+ concentration in the plating barrel when the present invention is implemented and when the conventional method is implemented. In the figure, 1: Plating tank, 2: Plating bath, 3: Sn supply tank, 4: Cuj+ supply tank, 5: Sn
50g addition device, 6: water addition device, 7: stirrer, 8: F
e5Ou addition device, 9: Inert Ganu supply device, 1°:
Cu5Oz h Addability, 11 near a! degree analyzer, 12:
Computer. No. (A) → Time M (day) 1 (B) → Time 311 (day) No. 3 (day) No. 4 (day) No. 4 (day) No. 4 (mm)

Claims (2)

[Claims] (1) In a method of replenishing Sn^2^+ ions to a plating bath in which bronze plating is performed using a sulfuric acid bath containing Sn^2^+ ions and Cu^2^+ ions, SnSO
_4 is made into a water bath liquid and stored in a supply tank, and this SnS
Continuously or intermittently replenishing the plating bath with the SnSO_4 aqueous solution while continuously or intermittently replenishing the O_4 aqueous solution with FeSO_4, or/and filling the replenishment tank with an inert gas. A method for replenishing metal components in a plating bath, characterized by: (2) A plating bath characterized in that a Sn^2^+ supply tank equipped with a SnSO_4 addition device, a water addition device, and an agitator is provided with a FeSO_4 addition device and/or an inert gas supply device. Metal component replenishment device.