JPH0665775A - Electrodeposition method of metal - Google Patents

Abstract

PURPOSE:To make an electrodeposition metal sufficiently porous regardless of the presence or absence of a treatment for making the surface of a work porous in the method for electrodepositing the metal on the work. CONSTITUTION:An anode and the work consisting of a metallic sheet are arranged within a plating cell (electrolyte) and a DC current is passed therebetween at the time of executing electrodeposition. The electrolyte prepd. by combining cations and anions having high ion mobility, for example, hydrobromic acid, is added to the electrolyte at this time. A large quantity of fine bubbles of gaseous hydrogen are then generated on the surface of the work regardless of the presence or absence of the treatment for forming the porous film and the metal is precipitated while the metal extends to enclose these bubbles. The porous electrodeposited nickel layer which is made sufficiently porous is thereby obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeposition method for electroplating, electroforming, or the like, in which the electrodeposited metal is made porous so as to be porous.

[0002]

2. Description of the Related Art For example, in electroplating, an object to be plated made of metal or having its surface subjected to conductive treatment is placed as a cathode in an electrolytic solution containing metal (for example, nickel) ions, and the metal to be electrodeposited (nickel, for example). ) Is disposed and a direct current is passed between the both electrodes to deposit a metal (nickel) in a thin film on the surface of the object to be plated. Further, the electroforming process uses, for example, a cathode obtained by subjecting the surface of a plastic mold to a conductive treatment, and similarly to electroplating, a surface of a metal is electrodeposited to a predetermined thickness, and then an electrodeposited metal is deposited. The desired product such as a molding die is obtained by peeling it from the mother die.

In such an electrodeposition technique, in order to prevent the formation of pits in the electrodeposited metal as much as possible, measures such as adding an anti-pit agent to the electrolytic solution are taken, and hydrogen is added to the cathode. I try to prevent the generation of air bubbles as much as possible.

On the other hand, in recent years, by electroforming,
For example, techniques for producing a porous molding die used for vacuum molding of plastic molded products have been developed (for example, JP-A-60-152692 and JP-A-61-2533).
No. 92). This technique, contrary to the above-mentioned general electrodeposition method, generates many fine bubbles of hydrogen gas on the surface of the mother die (cathode) having the same outer shape as the molded product and wraps the bubbles. By precipitating a metal,
It is intended to make the electrodeposited metal porous. For that purpose, the mother die is subjected to a porosity-treating process in which its surface layer is in a so-called fine mottled pattern between the conductive part and the insulating part, and an over electric field is generated at the boundary part between the conductive part and the insulating part to generate hydrogen gas. It is an attempt to actively generate it.

In this porosifying treatment, a spray liquid prepared by mixing a conductive paint with an insulating lacquer is sprayed on the surface of the mother die, or a conductive layer is formed on the surface of the mother die by a silver mirror reaction, and then the treatment is performed. This is performed by applying a silver corrosive agent to the conductive layer to remove a part of silver.

[0006]

By the way, the technique for obtaining a porous metal by electrodeposition should be utilized in various fields and applications in the future, in addition to the production of the above-mentioned vacuum forming mold. There is a possibility that As an example, by using a metal plate plated with a porous metal as a battery electrode, it is possible to obtain an electrode having an extremely large surface area and to achieve high capacity and downsizing of the battery. Can be done.

However, in the above-mentioned conventional technique for producing a porous mold by electroforming, the surface of the mother die is subjected to a porous treatment in which conductive portions and insulating portions are mixed in fine spots. It was essential to do. Therefore, when the electrodeposited object is a metal (electric conductor), it is impossible to electrodeposit the metal in a porous form. Further, for example, an insulating electrodeposited object is subjected to a porosification treatment. Even in this case, once the electroforming process was interrupted, there was a problem that the electrodeposited metal did not become porous even after the electroforming process was restarted.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for electrodepositing a metal on an object to be electrodeposited, regardless of whether the surface of the object to be electrodeposited is porous or not. Another object of the present invention is to provide a method for electrodepositing a metal which can sufficiently make the electrodeposited metal porous.

[0009]

In the method for electrodepositing a metal of the present invention, an anode and an electrodeposit are placed in an electrolytic solution containing metal ions, and an electric current is passed between the anode and the electrodeposit. A method for electrodepositing a metal on the object to be electrodeposited by adding an additive consisting of an electrolyte in which a cation and anion having high ion mobility are combined to the electrolytic solution. The feature is that the metal is made porous.

In this case, hydrohalic acid is preferable as the additive.

[0011]

[Function] In order to make the metal electrodeposited on the electrodeposit to be porous, an infinite number of fine bubbles such as hydrogen gas are generated on the surface of the electrodeposit and the metal is charged while enclosing the bubbles. Just wear it. In this case, conventionally, in order to generate the bubbles necessary for the porosity, the surface of the electrodeposited object may be subjected to a porosification treatment in which conductive parts and insulating parts are mixed in fine spots. Was considered essential.

On the other hand, the present inventors, without being bound by such conventional common sense, take new measures on the side of the electrolytic solution so that the porosity of the electrodeposited metal can be obtained regardless of the porous treatment. Based on the idea that it would be possible to generate the bubbles necessary for quality improvement, various experiments and studies were repeated. As a result, by adding to the electrolytic solution an additive composed of an electrolyte in which a cation and an anion having high ion mobility are combined, the surface of the entire surface is, of course, not only the object to be electrodeposited which has been treated for porosity. It has been clarified that even in the object to be electrodeposited which is a conductive layer, bubbles necessary for making the electrodeposited metal porous can be generated.

That is, the additive composed of the electrolyte is ionized into cations and anions in the electrolytic solution, and when the energization is started, these ions are attracted to the cathode and the anode, respectively. Since the ions have high ion mobility, the reactions of the ions at both electrodes are promptly performed, and a large amount of hydrogen gas is generated on the surface of the cathode, that is, the surface of the electrodeposit. Therefore, according to the present invention, it is possible to generate bubbles necessary for sufficiently making the electrodeposited metal porous regardless of the presence or absence of the porous treatment.

In this case, various additives can be used as the additive as long as they are electrolytes in which cations and anions having a high ion mobility are combined, but HCl, HBr, HI.
Particularly preferred are hydrohalic acids such as

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, the electrodeposition method of the present embodiment when electroplating nickel on a thin metal plate will be described. FIG. 2 schematically shows an electroplating apparatus 1 used in this embodiment, in which the plating bath 2 contains:
For example, the electrolytic solution 3 having nickel sulfamate as a main composition is contained in a state of being maintained at a required pH and temperature.

In the electrolytic solution 3, an additive such as hydrobromic acid (HBr), which is an electrolyte in which a cation having a high ion mobility and an anion are combined, is required (for example, 2 cc / l). ) Has been added.

In this case, as the cations and anions having high ion mobility, those shown in Table 1 below are listed.

[0018]

[Table 1]

As the additive, any combination of the cations and anions shown in Table 1 can be used, but a combination of hydrogen ions and halogen ions can be used. Especially preferred are hydrohalic acids such as HCl, HBr, HI and the like.

When performing electroplating, the anode 4 made of nickel is placed in the plating bath 2 and the electrodeposit 5 made of a thin metal plate is placed as a cathode. Then, a DC power supply 6 is connected between the both poles 4 and 5 to flow a DC current so as to obtain a required current density.

Then, an electrolytic reaction causes nickel metal to be deposited on the surface of the material 5 to be electrodeposited for electrodeposition. At this time, an additive (hydrobromic acid) added to the electrolytic solution 3 is used.
Ionizes hydrogen ions and bromine ions, and
These ions are attracted to the cathode (electrodeposit 5) and the anode 4, respectively. At this time, since the ions have a high ion mobility, the reaction of the ions on the surface of the electrodeposited material 5 and the anode 4 is promptly performed, and the hydrogen gas on the cathode, that is, the surface of the electrodeposited material 5 becomes fine. A lot of bubbles will be generated.

Nickel comes to be deposited on the surface of the electrodeposited object 5 while extending so as to wrap around a large number of fine bubbles adhering to the surface of the electrodeposited object 5, and the nickel electrodeposition progresses. Along with this, bubbles are further attached to the outside of the electrodeposit 5 so as to be continuous from the bubbles on the surface of the electrodeposit 5, and nickel is further deposited while extending so as to wrap the bubbles.

As a result, nickel is electrodeposited in a porous manner on the surface of the electrodeposited material 5, and when the electrodeposition of a predetermined thickness is completed, as shown in FIG. 5
Thus, the porous metal plate 8 integrally having the porous electrodeposited metal (nickel) layer 7 including the innumerable continuous pores 7a on the surface thereof is obtained.

The porous metal plate 8 thus obtained
Can be used, for example, as an electrode of a battery. Since the surface area of the porous metal plate 8 is extremely large, if it is used as an electrode, it is possible to increase the voltage, capacity, and size of the battery.
In this case, a nickel plate or the like made porous by sintering has been conventionally provided as an electrode of a battery, but the porous metal plate 8 of the present embodiment has much finer and larger number of pores 7a. Therefore, an extremely large surface area (for example, 70 to 80 times as large as that of a flat plate) can be obtained, and the function as an electrode becomes much superior.

As described above, according to the electrodeposition method of this embodiment,
By adding an additive composed of an electrolyte in which cations and anions having a high ion mobility are combined to the electrolytic solution 3, even if it is on the surface of the electrodeposited object 5 made of a metal plate, a large amount of fine particles can be obtained. It became possible to generate bubbles. Therefore, it is possible to sufficiently make the electrodeposited nickel layer 7 porous regardless of the presence or absence of the treatment for making the surface of the object 5 to be electrodeposited, which has been conventionally considered essential.

FIG. 3 shows another embodiment of the present invention. For example, the electrodeposit 1 made of a thin plastic plate.
A metal is electrodeposited on the surface of No. 1 in a porous form. In this case, first, the conductive layer 12 is formed on the surface of the object 11 to be electrodeposited by a method such as chemical plating or vapor deposition, and thereafter, an additive is added as in the above-mentioned embodiment. The electrolytic solution 3 is used for electrodeposition. In this way, the plastic plate 14 having the porous electrodeposited metal layer 13 on the surface can be obtained. The plastic plate 14 provided with the porous metal layer 13 thus obtained can be used as a high-quality radio wave absorber for applications such as radio wave shields.

FIG. 4 shows another embodiment in which a porous metal layer 16 is spherically charged at the tip of a metal-made ultrafine tube 15 such as an injection needle as an object to be electrodeposited. It is a dress. In this case, the electrodeposition may be performed in the same manner as above with the portion of the tube 15 other than the tip end portion being masked with, for example, a silicone resin. A tube 1 having a spherical porous metal layer 16 thus obtained at its tip
5 can be used, for example, as a pen tip of a writing instrument or a print head of a dot printer.

Further, although illustration and detailed description are omitted, for example, a porous molding die for vacuum molding can be manufactured by electroforming. This porous mold has a porous metal by electrodepositing a metal on the surface of a master mold, which is an electrodeposit having the same outer shape as the molded product, and then peeling the porous electrodeposited metal layer from the master mold. A mold can be obtained. In this case, the electroforming process can be suspended and restarted. It is even more effective if the surface of the mother die is subjected to a porosity treatment in which the conductive portion and the insulating portion are in a so-called minute spot shape.

Besides, the present invention is not limited to the embodiments described above and shown in the drawings, and it is possible to make the electrodeposited metal porous for the materials to be electrodeposited of various materials and shapes. The thickness and shape of the electrodeposited metal layer, and the size and number of pores can be variously changed. In this case, the appearance of the surface of the plating layer according to the present invention is not a metallic luster, but a dull and dull color tone like smoky silver, and a design effect can be obtained.

Further, as the kind of electrodeposited metal, not only nickel but also various kinds such as gold, silver, copper, chromium, zinc, tin, etc. are variously modified without departing from the scope of the present invention. Is possible. The product obtained by using the metal electrodeposition method of the present invention may be widely used in various fields and applications in the future.

[0031]

As is clear from the above description, according to the metal electrodeposition method of the present invention, an additive composed of an electrolyte in which a cation and an anion having high ion mobility are combined in an electrolytic solution. Since it is added, it is possible to sufficiently make the electrodeposited metal porous regardless of the presence or absence of the treatment for making the surface of the electrodeposited substance porous, and the product can be used for a wide range of purposes. That is an excellent effect.

[Brief description of drawings]

FIG. 1 is a partial enlarged vertical sectional view of a porous metal plate showing an embodiment of the present invention.

FIG. 2 is a diagram schematically showing an electroplating apparatus.

FIG. 3 is a partially enlarged vertical sectional view of a plastic plate showing another embodiment of the present invention.

FIG. 4 is an enlarged front view showing another different embodiment.

[Explanation of symbols]

In the drawing, 1 is an electroplating apparatus, 2 is a plating tank, 3 is an electrolytic solution, 4 is an anode, 5, 11 and 15 are electrodeposits, 6 is a DC power source, and 7, 13 and 16 are porous electrodeposited metal layers. , 8 is a porous metal plate, and 12 is a conductive layer.

Claims (2)

[Claims] 1. A method of depositing a metal on an electrodeposited material by placing an anode and an electrodeposited material in an electrolytic solution containing metal ions and applying a current between the anode and the electrodeposited material. In addition, in the electrolytic solution, by adding an additive comprising an electrolyte in which a cation and an anion having high ion mobility are combined, the electrodeposited metal is made porous. Metal electrodeposition method. 2. The method for electrodepositing a metal according to claim 1, wherein the additive comprises hydrohalic acid.