JPH09316696A - Electroplating anode and plating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of a plating layer due to a change in the distance between electrodes. SOLUTION: An anode 2 having a cylindrical anode main body 3 consisting of a soluble metal is disposed inside a material 1 to be plated having a cylindrical inner periphery 1a to be plated, the main body 3 is increased in diameter as the main body 3 is dissolved, hence the distance between the inner periphery 1a and the main body 3 is kept almost constant, and the inner periphery 1a is electroplated. Consequently, the distance between the electrodes is not increased, the plating rate is not lowered, the thickness of the plating film is made uniform, and the plating film is not deteriorated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroplating anode made of a soluble metal and a plating method using the electroplating anode.

[0002]

2. Description of the Related Art Conventionally, when electroplating the inner peripheral surface of a cylindrical object 81 to be plated, as shown in FIG. 5, a strip-shaped anode case 82 made of an inert metal such as titanium is used. An anode filled with the soluble anode piece 83 was used. In this plating method, when a voltage is applied from the rectifying device 84 between the object 81 to be plated as the cathode and the soluble anode piece 83 via the anode case 82, the plating component emits electrons from the soluble anode piece 83. It dissolves as an ion, and this ion migrates in the plating solution 85 toward the object 81 to be plated. Then, in the object 81 to be plated, which is the cathode, the ions receive electrons and deposit as plating metal. As a result, a plating layer is formed on the inner peripheral surface of the object 81 to be plated. Note that the soluble anode piece 83 in the anode case 82 is melted and consumed as the plating progresses, so it is necessary to supplement the reduced amount of the soluble anode piece 83 in the anode case 82.

[0003]

However, in the above conventional method, since the anode piece 83 becomes smaller due to melting, the excessively melted anode piece 83 falls off from the opening of the anode case 82, and the plating solution 85 is contaminated. There is a problem that
Therefore, the anode piece 83 in the anode case 82 is regularly
It is necessary to perform sizing to remove the excessively melted anode piece 83 having a small diameter.

As a countermeasure against the above problem, it is conceivable to make the opening of the anode case 82 small, but in this case, the contact area between the anode piece 83 and the plating solution 85 is reduced, so that the dissolution efficiency of the anode piece 83 is lowered. There is a problem that the plating rate decreases. In addition, the anode piece 83 and the anode case 8
It is conceivable to use an anode material formed into a cylindrical shape without using No. 2, but in this case, the outer diameter of the cylindrical anode material decreases with the progress of plating, and as a result, the object 81 to be plated as the cathode is Since the distance between the electrodes and the anode material increases, the plating rate may be reduced, and the quality such as the plating film thickness distribution may be adversely affected.

The present invention has been made in view of the above circumstances, and does not cause problems such as contamination of the plating solution and reduction of the plating rate, and further prevents deterioration of the quality of the plating layer due to changes in the distance between the electrodes. It is a technical problem to be solved to provide a positive electrode for electroplating and a plating method that can be performed.

[0006]

The electroplating anode of the present invention for solving the above-mentioned problems is an anode for electroplating a surface to be plated, which is composed of a cylindrical inner peripheral surface of an object to be plated, and is a soluble metal. It is characterized by comprising a cylindrical anode body made of and a diameter expanding means arranged inside the anode body for expanding the diameter of the anode body.

In a preferred embodiment of the electroplating anode of the present invention, the anode body is provided with slits extending in the entire axial direction, and is provided with rotating means for rotating the anode body. The plating method of the present invention that solves the above problems,
An anode having a cylindrical anode body made of a soluble metal is disposed inside an object to be plated having a surface to be plated made of a cylindrical inner peripheral surface, and the anode body is moved as the dissolution of the anode body progresses. By increasing the diameter, electroplating is performed on the surface to be plated while keeping the distance between the surface to be plated and the anode body substantially constant.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The electroplating anode of the present invention is for electroplating a surface to be plated, which is a cylindrical inner peripheral surface of the object to be plated. The material to be plated is not particularly limited as long as it can act as a cathode during the electroplating process, and can be appropriately selected. Specific examples of the object to be plated having a surface to be plated formed of a cylindrical inner peripheral surface include iron-based materials, aluminum alloy-based materials, and magnesium alloy-based materials.

The electroplating anode of the present invention comprises a cylindrical anode body made of a soluble metal and a diameter expanding means arranged inside the anode body for expanding the diameter of the anode body. The material of the anode body is not particularly limited as long as it acts as an anode during electroplating and can dissolve into a plating solution to become ions, and can be appropriately selected. For example, lead, iron-based alloys, nickel-based alloys, chromium-based alloys, etc. can be used for the anode body.

It is preferable that the cylindrical anode body is provided with a slit extending along the entire axial length. Although the effect of the present invention described below can be obtained by expanding the outer diameter of the anode body by elastic or plastic deformation of the anode body itself,
By using the anode body provided with the slit, it is possible to increase the diameter expansion amount of the anode body,
More effective. The slits may be provided in two or more places at intervals in the circumferential direction of the anode body.

When the anode main body provided with the slits is used as described above, the slits make the current distribution non-uniform, which may adversely affect the plating film thickness distribution in the portion facing the slits. For this reason, when the anode main body provided with the slit is used, it is preferable to provide a rotating means for rotating the anode main body. By performing the plating while rotating the anode body, it is possible to make the current distribution uniform and the plating film thickness uniform in the circumferential direction.

The diameter expanding means is not particularly limited as long as it can expand the outer diameter of the anode body by pressing the anode body radially outward from the inner peripheral surface of the anode body. For example, it has a cylindrical outer peripheral surface that extends substantially parallel to the axial center and has a uniform outer diameter in the axial direction, and a conical inner peripheral surface whose inner diameter gradually decreases toward one of the axial centers. A thick-walled cylindrical member extending in the radial direction in a cross section and having a plurality of incisions formed alternately from a cylindrical outer peripheral surface and a conical inner peripheral surface, the diameter of which can be expanded and reduced, and this thick wall The wedge member is disposed inside the cylindrical member and has a conical outer peripheral surface corresponding to the conical inner peripheral surface of the thick-walled cylindrical member, and a driving means for moving the wedge member in the axial direction. It can be a diameter expanding means. In the diameter expanding means having this structure, the conical outer peripheral surface of the wedge member presses the conical inner peripheral surface of the thick-walled cylindrical member by moving the wedge member to one of the axes by the driving means. As a result, a radially outward force acts on the peripheral wall of the thick-walled cylindrical member, and the thick-walled cylindrical member expands in diameter. As a result, the cylindrical outer peripheral surface of the thick-walled cylindrical member presses the inner peripheral surface of the peripheral wall of the anode body outward in the radial direction, so that the anode body can be expanded in diameter.

Further, as the diameter expanding means, a means composed of a bag-shaped member made of a soft material and a fluid pressure supply means for supplying a fluid pressure to the inside of the bag-shaped member can be adopted. By using the electroplating anode having the above-mentioned configuration, the plating method of the present invention can be carried out, and thereby the surface to be plated consisting of the cylindrical inner peripheral surface of the object to be plated can be favorably electroplated. .

That is, an anode having a cylindrical anode body made of a soluble metal is disposed inside an object to be plated having a surface to be plated having a cylindrical inner peripheral surface. Then, as the dissolution of the anode body progresses, the diameter of the anode body is expanded by the diameter expanding means, so that the distance between the surface to be plated of the object to be plated and the anode body is substantially constant, and the surface to be plated is electrically charged. It can be plated. Thus, even if the anode body is melted as the plating progresses, by compensating for the decrease in the outer diameter of the anode body due to melting by the diameter expansion of the anode body by the diameter expanding means, the surface to be plated and the anode body are Since it is possible to perform plating while keeping the distance between the electrodes substantially constant, it is possible to prevent the plating speed from decreasing with the increase in the distance between the electrodes, and adversely affecting the quality such as the plating film thickness distribution. Is possible.

Further, in the conventional method using a small piece of the soluble anode piece, there is a problem that the plating solution is contaminated by the excessively dissolved anode piece falling off from the anode case. Problem does not occur.

[0016]

EXAMPLES Examples of the present invention will be described more specifically below. (First Embodiment) In the present embodiment shown in FIGS. 1 to 3, electroplating is performed on a surface 1a to be plated, which is a cylindrical inner peripheral surface of a cylindrical object 1 to be plated. This object 1 to be plated is specifically an aluminum alloy casting.

Electroplating anode 2 used in this embodiment
Is composed of a cylindrical anode body 3, a diameter expanding means 4 for expanding the diameter of the anode body 3, and a rotating means 5 for rotating the anode body 3. The anode body 3 is formed of the material forming the plating layer, and is specifically made of Ni as a soluble metal. Then, as shown in FIG. 2, the anode body 3 is provided with one slit 31 extending in the entire axial length. The anode body 3 was formed by bending a plate having a thickness of 5 mm into a pipe shape.

The diameter expanding means 4 is a thick-walled cylindrical member 41 disposed inside the anode body 3 and the thick-walled cylindrical member 4
1, a wedge member 42 disposed inside 1 and a wedge member 4
It is composed of a drive means 43 for moving 2 in the axial direction. The thick-walled cylindrical member 41 is made of a hard resin as a material to be electrically conductive, extends substantially parallel to the axis P _C, and has a cylindrical outer peripheral surface 41a having an outer diameter that is uniform in the axial direction, and one of the axial outer surfaces. The inner peripheral surface 41b has a conical inner peripheral surface 41b whose inner diameter gradually decreases toward the upper side (upward in FIGS. 1 and 3, and the same below). Further, the thick-walled cylindrical member 41 has a plurality of notches 41c extending in a radial direction in a cross section and formed alternately from a cylindrical outer peripheral surface and a conical inner peripheral surface. This allows
The thick cylindrical member 41 can be expanded and contracted.
The thick cylindrical member 41 is fitted on the inner peripheral surface of the anode body 3.

The wedge member 42 is made of a hard resin as a material to be electrically conductive, and has a conical inner peripheral surface 4 of the thick-walled cylindrical member 41.
It has a conical outer peripheral surface 42a corresponding to 1b. The wedge member 42 is the conical inner peripheral surface 4 of the thick-walled cylindrical member 41.
It is fitted to 1b. The drive means 43 includes a U-shaped support column 44 fixed to one axial end of the thick-walled cylindrical member 41 (upper end in FIGS. 1 and 3, and the same below), and one axial end of the wedge member 42. The screw shaft 45 is fixed to the screw shaft 45 and a nut-shaped tightening member 46 screwed to the screw shaft 45. With this configuration, when the tightening member 46 is tightened to the screw shaft 45 in a state where the wedge member 42 is fitted to the conical inner peripheral surface 41b of the thick-walled cylindrical member 41, the wedge member 42 is tightened by the tightening. It is movable in one axial direction.

The rotating means 5 comprises a motor and is connected to one end of the screw shaft 45 of the driving means 43 in the axial direction. Therefore, when the rotating means 5 is driven, the screw shaft 45, the support column 44, the wedge member 42, and the thick-walled cylindrical member 41 rotate integrally and are fitted with the cylindrical outer peripheral surface of the thick-walled cylindrical member 41. The anode main body 3 to be rotated is rotatable. The electroplating anode 2 having the above configuration is immersed in the plating solution 7 contained in the plating tank 6, and is concentrically arranged inside the cylindrical object 1 to be plated, which is also immersed in the plating solution 7. To be done. The anode body 3 of the anode 2 is electrically connected to the anode of the rectifying device 8 via the first cable 9, and the object to be plated 1 as the cathode is electrically connected to the cathode of the rectifying device 8 via the second cable 10. Connected.

Then, the rotating means 5 is operated to rotate the anode body 3 relative to the object to be plated 1 while applying a voltage from the rectifying device 8 between the anode body 3 and the object to be plated 1. Perform plating treatment. In the plating process,
The plating component emits electrons from the anode body 3 and dissolves as ions, and the ions dissolve in the plating solution 7 to be plated 1.
Run to the side. In the object to be plated 1 which is the cathode, the above ions receive electrons and deposit as plating metal. Thereby, the plated surface 1a as the cylindrical inner peripheral surface of the plated object 1
Then, a plating layer is formed.

As the plating progresses, the anode body 3 is melted and the outer diameter of the anode body 3 is reduced. As the melting of the anode body 3 progresses, the tightening member 46 is tightened to the screw shaft 45. . As a result, the wedge member 42 moves in one axial direction, and the conical outer peripheral surface 4 of the wedge member 42 is moved.
1b is pressed against the conical inner peripheral surface 42a of the thick-walled cylindrical member 41. Thereby, the outward force in the radial direction acts on the peripheral wall of the thick-walled cylindrical member 41, and the thick-walled cylindrical member 41 expands in diameter. As a result, the cylindrical outer peripheral surface 41a of the thick-walled cylindrical member 41 presses the inner peripheral surface of the peripheral wall of the anode body 3 outward in the radial direction, so that the anode body 3 can be expanded in diameter.
Therefore, it is possible to perform electroplating on the plated surface 1a while keeping the distance between the plated surface 1a of the plated object 1 and the anode body 3 substantially constant. Thus, even if the anode body 3 is melted as the plating progresses, the amount of decrease in the outer diameter of the anode body 3 due to melting is compensated for by the diameter expansion of the anode body 3 by the diameter expansion means 4, and thus the surface to be plated. Since plating can be performed while keeping the distance between 1a and the anode body 3 substantially constant,
It is possible to prevent the plating rate from decreasing with an increase in the distance between the electrodes, and from adversely affecting the quality such as the film thickness distribution of the plating.

Further, in this embodiment, the anode body 3 is provided with the slit 31 extending in the entire axial direction, and the anode body 3 is provided with the slit 31.
In addition to the effect of expanding the diameter by the elastic deformation of itself, the effect of expanding the diameter by the slit 31 is added, so that the amount of expansion of the anode body 3 is large. Therefore, it is possible to compensate for the decrease in the outer diameter due to the dissolution of the anode body 3 for a long period of time, and it is possible to perform the plating treatment while keeping the inter-electrode distance constant for a long period of time.

Further, since the anode main body 3 provided with the slit 31 is used, the slit 31 makes the current distribution non-uniform, which may adversely affect the plating film thickness distribution. Since the plating is performed while rotating the anode body 3 relative to the object to be plated 1, it is possible to make the current distribution uniform and the plating film thickness uniform in the circumferential direction.

In the present embodiment, since the anode in which the small piece-shaped soluble anode piece is housed in the anode case is not used, the excessively dissolved anode piece is dropped from the anode case and the plating solution is contaminated. It goes without saying that the problem of (Embodiment 2) The present embodiment shown in FIG. 4 shows another mode of the diameter expanding means 4, which comprises a bag-shaped member 48 made of a soft material and the inside of the bag-shaped member 48. And a fluid pressure supply means 49 for supplying fluid pressure to.

The bag-shaped member 48 is made of a rubber material and has a fluid inlet 48a. Also, the fluid pressure supply means 49
The fluid pressure supplied from the inside to the bag-shaped member 48 is
Hydraulic pressure, atmospheric pressure, etc. can be adopted. According to this aspect, as the dissolution of the anode main body 3 progresses, the fluid pressure applied from the fluid pressure supply means 49 to the inside of the bag-shaped member 48 is increased, so that the bag-shaped member 48 expands, whereby the bag. Since the outer peripheral surface of the cylindrical member 48 presses the inner peripheral surface of the peripheral wall of the anode body 3 outward in the radial direction, the anode body 3 can be expanded in diameter.

[0027]

As described in detail above, according to the present invention, even if the anode body is melted with the progress of plating, the diameter of the anode body is increased to compensate for the decrease in the outer diameter of the anode body due to the melting. By doing so, it is possible to perform plating while keeping the distance between the surface to be plated and the anode body approximately constant, so that the plating speed decreases with an increase in the distance between the electrodes, and the quality of the plating film thickness distribution, etc. It is possible to prevent adverse effects.

Therefore, it is possible to quickly form a plating layer having a good quality such as the thickness distribution of plating on the surface to be plated as the cylindrical inner peripheral surface of the object to be plated. Further, by using the anode main body provided with the slits, it becomes possible to perform the plating treatment while keeping the distance between the electrodes constant for a long period of time. Further, by performing the plating treatment while rotating the anode body relative to the object to be plated, it is possible to make the current distribution uniform and the plating film thickness uniform in the circumferential direction.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an apparatus used in a method according to a first embodiment.

FIG. 2 is a plan view of the anode according to the first embodiment.

FIG. 3 is a cross-sectional view of an anode according to the first embodiment.

FIG. 4 is a sectional view of an anode according to a second embodiment.

FIG. 5 is a configuration diagram showing a form according to a conventional technique.

[Explanation of symbols]

In the figure, 1 is an object to be plated, 1a is a surface to be plated, 2 is an anode,
3 is an anode main body, 4 is a diameter expanding means, and 5 is a rotating means.

Claims (4)

[Claims] 1. An anode for electroplating a surface to be plated, which is composed of a cylindrical inner peripheral surface of an object to be plated, which is a cylindrical anode body made of a soluble metal, and is disposed inside the anode body. An electroplating anode, comprising: a diameter expanding means for expanding the diameter of the anode body. 2. The anode for electroplating according to claim 1, wherein the anode body is provided with a slit extending along the entire length in the axial direction. 3. The anode for electroplating according to claim 2, further comprising rotating means for rotating the anode body. 4. An anode having a cylindrical anode body made of a soluble metal is provided inside an object to be plated having a surface to be plated made of a cylindrical inner peripheral surface, and as the dissolution of the anode body progresses. And a diameter of the anode main body is increased so that the surface to be plated and the anode main body are electroplated while the distance between the surface to be plated and the anode main body is substantially constant.