JPH11209899A - Formation of plating solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method for excellently and stably forming a plating soln. using a plating soln. forming tank with the inside divided by a diaphragm. SOLUTION: The inside of a plating soln. tank 1 is divided with a diaphragm into an anode compartment 3 and a cathode compartment 4, and a current is applied between a plating metal 6 set in a plating soln. 5 in the anode compartment 3 and a cathode 8 set in an electrolyte 7 in the cathode compartment 4 to elute the metal ion into the plating soln. 5, and a plating soln. is formed. In this case, since a smoothing agent is added to the electrolyte 7 in the cathode compartment 4, the metal ion mixed in the electrolyte 7 is deposited smoothly and densely on the cathode 8 and grown dendritically, hence the diaphragm 2 is never broken, and the plating soln. 5 is excellently and stably formed. The spent cathode 8 having the smooth and dense surface is economically reused as such as the anode 6. Further, when a cation-exchange membrane 2 is used as the diaphragm, the intrusion of anion into the plating soln. 5 is prevented, and the acid concn. of the soln. 5 is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plating solution satisfactorily and stably using a plating solution producing tank partitioned by a diaphragm.

[0002]

2. Description of the Related Art Generally, plating metal ions are supplied to a plating tank by using a plating metal as an anode of the plating tank. However, in this method, the distance between the electrodes fluctuates as the anode is consumed. There are drawbacks such as the need for periodic replacement. Therefore, using an insoluble electrode for the anode of the plating tank,
A method of supplying a plating solution separately generated in a plating solution generation tank has been put into practical use. The supply plating solution is generated by a method of dissolving a plating metal salt or a plating metal with an acid or the like, a method of electrolyzing a plating metal, or the like.

[0003] In the method of electrolyzing the plating metal, for example, a plating solution producing tank is divided into an anode chamber and a cathode chamber by an anion exchange membrane (diaphragm), and an anode (plating solution) provided in the plating solution in the anode chamber is formed. An electric current is passed between the metal) and the cathode disposed in the electrolytic solution in the cathode chamber to elute the plating metal ions from the anode into the plating solution, and the plating metal ions enter the cathode chamber by anion exchange. This is a method in which a plating solution is generated by holding the film and staying in an anode chamber (plating solution). The plating solution generated in the anode chamber is circulated and used in a plating tank.

[0004]

However, in the above-mentioned method of partitioning the plating solution producing tank with an anion exchange membrane, the anions easily enter the anode chamber, and the entered anions are discharged at the anode to remove the acid. Because of the formation, the acid concentration of the plating solution fluctuates.
For this reason, a device for removing the acid is required, which is disadvantageous in cost.

Therefore, the present inventors have tried to prevent the intrusion of anions into the anode chamber by partitioning the plating solution producing tank with a cation exchange membrane (diaphragm). As a result, it was confirmed that the acid concentration of the plating solution was kept constant. However, this method
As shown in FIG. 2, the plating metal ions M ⁺ in the plating solution generating tank 1 permeate the cation exchange membrane 2 and gradually mix into the electrolyte solution 7 in the cathode chamber 4, which precipitates on the cathode 8, The precipitate 11 grows in a dendritic manner (as shown) and damages the cation exchange membrane 2. Further, the dendritic precipitate 11
When the tip reaches the inside of the anode chamber 3, the plating solution 5 in the anode chamber 3 contains a large amount of plating metal ions, so that the dendritic precipitate 11 grows rapidly and reaches the anode 6 and immediately reaches the anode 8. , 6 was short-circuited. Further, the dendritic precipitates 11 are separated by the stirring of the electrolyte solution 7 and damage the cation exchange membrane 2. In FIG. 2, reference numeral 10 denotes a plating tank, 12 denotes an anode of the plating tank, 13 denotes a material to be plated, and 9 denotes a circulation hype.

[0006] When the membrane is an anion exchange membrane, the contamination of metal ions into the cathode compartment is slight, and dendritic deposits on the cathode do not grow to reach the anion exchange membrane. The anion exchange membrane may be peeled off by stirring and may be damaged. An object of the present invention is to provide a method for producing a plating solution satisfactorily and stably using a plating solution producing tank partitioned by a diaphragm.

[0007]

According to the first aspect of the present invention,
The plating solution generation tank is divided into an anode chamber and a cathode chamber by a diaphragm, and a current is applied between the anode (plating metal) disposed in the plating solution in the anode chamber and the cathode disposed in the electrolyte in the cathode chamber to perform plating. A plating solution producing method for eluting plating metal ions into a solution, wherein a plating smoothing agent is added to the electrolytic solution in the cathode chamber.

The invention according to claim 2 is the method for producing a plating solution according to claim 1, wherein the diaphragm is a cation exchange membrane.

According to a third aspect of the present invention, there is provided a method for producing a plating solution according to the first or second aspect, wherein the concentration of the deposition smoothing agent in the electrolytic solution in the cathode chamber is controlled to 0.005 g / liter or more. It is.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 is an explanatory view showing an embodiment of the plating solution generation method of the present invention. A plating solution generating tank 1 is partitioned by a cation exchange membrane 2 into an anode chamber 3 and a cathode chamber 4;
An anode (plating metal) 6 is provided in a plating solution 5 in the anode chamber 3, and a cathode 8 is provided in an electrolyte 7 in the cathode chamber 4. In order to obtain a smooth and dense plated surface of the material 13 to be plated in the plating solution 5 and to prevent dendritic deposition on the cathode 8 in the electrolytic solution 7, a predetermined amount of a deposition smoothing agent (hereinafter, referred to as a plating smoothing agent) is used. , Abbreviated as a smoothing agent).

When an electrolysis is performed by passing a current between the anode 6 and the cathode 8, plating metal ions are eluted into the plating solution 5, and most of the plating metal ions do not pass through the cation exchange membrane 2 but remain in the plating solution. And a plating solution is generated. The hydrogen ions generated simultaneously with the elution of the plating metal ions pass through the cation exchange membrane 2 and reach the cathode 8, where they are discharged and turned into hydrogen gas and released into the atmosphere. Some of the plating metal ions permeate through the cation exchange membrane 2 and precipitate on the cathode 8, but since the smoothing agent is added to the electrolytic solution 7,
The plating metal ions are deposited on the cathode 8 in a smooth and dense manner.
Therefore, the precipitates do not grow in a dendritic manner, and do not damage the cation exchange membrane 2 or short-circuit the anode 6 and the cathode 8. The plating solution 5 generated in the anode chamber is circulated to a plating tank 10 through a circulation pipe 9. Plating tank 10
In the above, since the smoothing agent is added to the plating solution, the material to be plated is subjected to smooth and dense plating.

In the present invention, a plating metal is used for the anode of the plating solution producing tank. As a plating solution for alloy, a method of using a main component metal for an anode and supplying a subcomponent metal as a salt to the plating solution, or a method of using the anode itself as an alloy is applied. The shape of the anode is arbitrary, such as a plate, a rod, and a grain. In the case of particles, they are used in a conductive basket, cloth bag or the like which is not affected by the plating solution.

[0013] The material of the cathode of the plating solution producing tank is not particularly limited, but the same material as the anode (plating metal) can be reused as an anode after use, and stainless steel, etc., from which precipitates are easily peeled off, can be used as a precipitate. Is easy to reuse,
Each is advantageous in cost.

In the present invention, the electrolytic solution in the cathode chamber is not particularly limited as long as it is an electrolytic solution. However, an acid solution containing the same anion as the plating solution is used so that even if mixed in the plating solution, plating quality is not affected. Is desirable. As the leveling agent, a commercially available chemical commonly used for plating or electrolytic refining such as gelatin, polyethylene glycol, and cresol sulfonic acid is used. The smoothing agent added to the electrolytic solution in the cathode compartment does not adversely affect the plating quality even when mixed into the plating solution,
Alternatively, the same leveling agent as that added to the plating solution is desirable. A plurality of leveling agents may be used in combination.

In the present invention, the concentration of the leveling agent in the electrolytic solution is desirably controlled to 0.005 g / liter or more. The reason is that if the amount is less than 0.005 g / liter, the effect cannot be sufficiently obtained. Even if the concentration of the leveling agent exceeds 5 g / l, the effect is saturated and uneconomical, so that it is usually desirable to set the upper limit to 5 g / l. However, in some cases, the plating solution contains a large amount of a smoothing agent that itself plays a role of an acid, such as sulfonic acids, and in such a case, it is not necessary to stick to the upper limit. Although the leveling agent is consumed with the deposition of the plating metal, the current efficiency of the deposition of the plating metal at the cathode is low, so that a sufficient effect of the leveling agent is expected at an addition amount of 0.005 g / liter or more. it can.

When the surfactant is contained in the leveling agent, the amount of the surfactant in the electrolytic solution increases with the consumption of the leveling agent, and the electrolytic solution foams by stirring and overflows from the production tank. Workability is deteriorated. In such a case, it is desirable to use a leveling agent containing no surfactant.

[0017]

(Plating solution generation tank)

Anode and cathode: Sn plate with 99.99% purity. Cation exchange membrane: Selemion CMV (Asahi Glass Co., Ltd.)
Made). Effective area of cation exchange membrane: 1.0 dm ² . Plating solution: 80.0 g / liter of sulfuric acid, 63.2 g / liter of stannous sulfate (35.0 g / liter of tin), 25.0 g / liter of leveling agent (UTB-513Y, including surfactant, manufactured by Ishihara Chemical Co., Ltd.) . Plating solution volume 250ml. Electrolyte solution: sulfuric acid 80.0 g / liter, leveling agent (UTB-513Y above)
0.003 to 10 g / liter. Electrolyte volume 250ml. [Plating bath] Anode: Pt plated Ti. Cathode: copper alloy plate. Plating solution: Same as in plating solution generation tank.

Example 2 Same as Example 1 except that the concentration of UTB-513Y in the electrolytic solution was 1.0 g / liter and gelatin (without surfactant) was added as a leveling agent at 0.5 g / liter. A Sn plating solution was generated by the method, and Sn was plated on a material to be plated using the plating solution.

(Comparative Example 1) An Sn plating solution was produced in the same manner as in Example 1 except that no leveling agent was added to the electrolytic solution, and Sn was plated on a material to be plated using this plating solution. .

In Examples 1 and 2 and Comparative Example 1, the surface properties (smoothness and precipitate density) of the cathode after the plating solution was continuously produced for 24 hours were examined. Table 1 shows the results. Table 1 also shows the state of the electrolytic solution during the generation of the plating solution.

[0021]

[Table 1] (Note) * ◎ Extremely good, ○ good, △ slightly poor, but no practical problem. * In addition to UTB-513Y, gelatin was further added.

As is clear from Table 1, No. 1 of the present invention example
However, the properties of the cathode surface (smoothness and density of precipitates) were slightly reduced because the amount of the smoothing agent was slightly small. Nos. 2 to 8 contain a sufficient amount of leveling agent (UTB-513Y),
The properties of the cathode surface were good or extremely good. Among them, Nos. 5 to 7 contained a large amount of UTB-513Y, and the surfactant contained therein was dissolved in the electrolytic solution, and foaming occurred in the electrolytic solution. In particular, No. 7 had a lot of foaming, and time-consuming workability for removing foam deteriorated. No.8 is UTB- compared to No.5.
The amount of 513Y was reduced and gelatin containing no surfactant was added by 0.5 g / liter. The surface properties of the cathode were extremely good, and the electrolyte solution did not foam. In addition, in the above Nos. 1 to 8, the precipitate did not grow in a dendritic manner, so that the precipitate was not peeled off by stirring of the electrolytic solution and the cation exchange membrane was not damaged. On the other hand, in Comparative Example No. 9, Sn was deposited in a dendritic manner on the cathode surface because no smoothing agent was added to the electrolytic solution, and the dendritic deposits penetrated the cation exchange membrane (the cathode and the cation exchange membrane). Is 55mm)
The tip reached the anode compartment. In the cathode used in the above example, Sn was deposited smoothly and densely, and could be reused as an anode. Further, the plating solution produced by the above example had a stable acid concentration, and the Sn plating layer was favorably formed on the copper alloy plate in the plating bath.

In the present invention, the effect is particularly exhibited when the membrane is a cation exchange membrane, but a corresponding effect can be obtained when the membrane is an anion exchange membrane.

[0024]

As described above, in the present invention, since the smoothing agent is added to the electrolytic solution in the cathode chamber, the plating metal ions mixed in the electrolytic solution are smooth and densely deposited on the cathode.
The plating solution is satisfactorily and stably formed without growing dendrites and damaging the cation exchange membrane. In addition, the cathode after use has a smooth and dense surface and can be reused as an anode as it is, which is economical. When a cation exchange membrane is used for the diaphragm, the anion is prevented from being mixed into the plating solution, and the acid concentration of the plating solution is stabilized. Therefore, an acid removing device is unnecessary and economical.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a plating solution generating method of the present invention.

FIG. 2 is an explanatory view of a conventional plating solution generation method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 plating solution generating tank 2 cation exchange membrane 3 anode compartment 4 cathode compartment 5 plating solution in anode compartment 6 anode 7 electrolyte in cathode compartment 8 cathode 9 circulation pipe 10 plating tank 11 dendritic precipitate 12 anode of plating tank 13 coating Plating material

Claims (3)

[Claims] 1. A plating solution producing tank is partitioned by a diaphragm into an anode chamber and a cathode chamber, and between the anode (plating metal) disposed in the plating solution in the anode chamber and the cathode disposed in the electrolytic solution in the cathode chamber. What is claimed is: 1. A method for producing a plating solution, in which a plating current is eluted into a plating solution by passing an electric current, wherein a deposition smoothing agent is added to the electrolyte solution in the cathode chamber. 2. The method according to claim 1, wherein the diaphragm is a cation exchange membrane. 3. The method for producing a plating solution according to claim 1, wherein the concentration of the deposition smoothing agent in the electrolytic solution in the cathode chamber is controlled to 0.005 g / liter or more.