JP2002030488A - Dispersive plating method by electromagnetic agitation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dispersive plating method capable of realizing the uniform eutectic of the dispersant of sufficient amount in order to give the function in a plating film, having high rate of utilization of the dispersant and high plating speed, and capable of controlling the eutectic ratio of the dispersant and the eutectic mode of the dispersant particles. SOLUTION: In the dispersive plating method comprising a first step of installing a work 2 and a facing electrode 3 in a plating solution, a second step of bringing the dispersant for the eutectic in the plating film into contact with the work 2, and a third step of realizing the precipitation of the plating metal and the eutectic of the dispersant by running the direct current from an external power supply 5 so that the work 2 forms a cathode and the facing electrode 3 forms an anode, the plating is implemented by applying the magnetic field so as to generate the line of magnetic force parallel to the direction of the current running in the plating solution 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a dispersion plating method.

[0002]

2. Description of the Related Art Conventionally, a dispersion plating method has been developed and put to practical use for the purpose of imparting new functionality to a plating film. This plating method is a technique in which dispersant particles are eutectoid in a plating film by performing plating in a state where a dispersant is present in a plating bath. According to this method, a plating film having various functions can be obtained by selecting a dispersant to be eutectoid. For example, when a powder of high hardness such as alumina or diamond is used as the dispersing material, a wear-resistant plating film can be obtained. Also,
If a solid lubricant such as Teflon (registered trademark) powder is used,
It is possible to obtain a plating film having excellent lubricity.

In this dispersion plating method, it is necessary to uniformly suspend the dispersant in a plating solution in order to uniformly eutect the dispersant in the plating film. Therefore, during plating, plating has been performed while stirring the plating solution by a method such as blowing air, flowing a plating solution by a pump, or rotating a propeller.

[0004]

However, with such a stirring method, it is difficult to uniformly suspend a dispersion material having a large specific gravity or a dispersion material having a large particle diameter in a plating solution. There is a drawback that a uniform and sufficient amount of a dispersant cannot be co-deposited in the plating film. In addition, even for a dispersant capable of uniform suspension, there is a certain limit to the eutectoid rate of the dispersant in the plating film, and in many cases, it is insufficient to exhibit its functionality. There was also a disadvantage that the utilization rate of the material was low. Furthermore, in such a dispersion plating method, it is necessary to control the eutectoid rate of the dispersing material, align the eutectoid state of the dispersing material particles in a certain direction, or orient the fibrous dispersing material in the plating film. Was difficult.

On the other hand, the plating object is placed horizontally in the plating solution to which the dispersing agent is added, the plating solution is intermittently stirred, and plating is performed while taking in the dispersing agent which settles when the stirring is stopped. A method of eutecting a dispersant into a plating film has also been practiced (so-called sedimentation eutectoid method). According to this method, even with a dispersant having a large specific gravity or a dispersant having a large particle diameter, it is possible to obtain a plating film having a uniform and sufficient eutectoid rate, and the utilization factor of the dispersant is high.

However, in this method, the limiting current density is reduced due to the inability to stir the plating solution during plating and the deposition of the settling dispersant on the surface of the object to be plated. Therefore, there is a disadvantage that good plating cannot be obtained unless plating is performed at a relatively low speed. Further, it is still difficult to control the eutectoidity of the dispersant, to arrange the dispersant particles in a certain direction, or to orient the fibrous dispersant in the plating film.

[0007] As another dispersion plating method, a plating object is surrounded by a mesh through which a plating solution passes but a dispersion material cannot pass, and a high concentration of the dispersion material is present in the mesh to shorten the plating time. There is also a dispersion plating method in which after a certain period of time, the dispersing material is held on the plating surface (temporary fixing step), the object to be plated is taken out, and the dispersing material is embedded by performing normal plating (embedding step) (so-called temporary fixing). Law).
According to this method, even with a dispersant having a large specific gravity or a dispersant having a large particle diameter, it is possible to obtain a plating film having a uniform and sufficient eutectoid rate, and the utilization rate of the dispersant is relatively high. .

However, this method has a drawback that the productivity is inferior since two plating steps of a temporary fixing step and an embedding step are required. In addition, in the temporary fixing step, since the plating is carried out with a high concentration of the dispersing material present in the mesh, a normal plating film is difficult to be formed, and there is a possibility that the dispersion plating film lacks adhesion. Furthermore, it is still difficult to control the eutectoidity of the dispersant, to arrange the dispersant particles in a certain direction, or to orient the fibrous dispersant in the plating film.

The present invention has been made in view of the above-mentioned problems of the conventional dispersion plating technique, and enables a sufficient amount of a dispersant to be uniformly eutectoid in order to impart a function to a plating film.
An object of the present invention is to provide a dispersion plating method in which the utilization rate of a dispersant is high, the plating rate is high, and the eutectoid rate of the dispersant and the eutectoid form of the dispersant can be controlled.

[0010]

According to the dispersion plating method of the present invention, there is provided a method of disposing a plating object and a counter electrode in a plating solution.
A second step of contacting the object to be plated with a dispersing material for causing eutectoid in a plating film; and applying a direct current from an external power supply so that the object to be plated serves as a cathode and the counter electrode serves as an anode. In the dispersion plating method comprising the third step of evaporating the dispersing material together with the deposition of the plating metal by applying the magnetic field, a magnetic field is applied so that the magnetic force lines are generated in a direction substantially parallel to the direction of the current flowing in the plating solution. It is characterized by performing plating while performing.

In the present invention, the dispersant is co-deposited in the plating film by contacting the object to be plated with a dispersing material for eutectoid in the plating film and plating in this state. The method for bringing the dispersant into contact with the object to be plated in advance is not particularly limited.For example, the object to be plated is surrounded by a mesh through which the plating solution passes but the dispersant cannot pass, and the dispersant is placed in the mesh. It is possible to adopt a method of causing a high concentration to be present.

As a feature of the present invention, the magnetic field lines are generated in a direction substantially parallel to the direction of the current flowing in the plating solution.
Plating while applying a magnetic field. In the vicinity of the particles of the dispersing material that comes into contact with the object to be plated, the direction of the current is locally changed due to the presence of the particles of the dispersing material, and a current component that is not parallel to the lines of magnetic force appears. From the relationship, Lorentz force is generated such that a vortex around the particle is generated. This Lorentz force is generated not only by the presence of the particles of the dispersing material, but also by irregularities on the surface of the object to be plated or fine hydrogen bubbles generated as a side reaction of plating. The local current of the plating solution is locally agitated due to the Lorentz force, so that the limiting current density increases, and plating at a high current density becomes possible. Can be eutectoid.

According to this method, since the state of the dispersing material in contact with the object to be plated is eutectoid in the plating film almost as it is, even if the dispersing material has a large specific gravity or a large particle size, the dispersing material has a large particle size. It becomes possible to cause eutectoids inside. Even if the amount of the dispersant added to the plating solution is very small, if an appropriate amount of the dispersant is present in the vicinity of the object to be plated, a sufficient amount of the dispersant is required to impart a function to the plating film. Can be eutectoid, and the utilization of the dispersant can be greatly improved.

In the dispersion plating method of the present invention, in the first step, the object to be plated is extended in the plating solution in a substantially horizontal direction, and a counter electrode is provided above the object to be plated.
A method may be employed in which a dispersant for causing eutectoid in a plating film is previously deposited on the object to be plated.

[0015] In this case, even if the dispersant is added to the plating solution in a very small amount, the dispersant can be brought into contact with the object to be plated at a high density, and the function is added to the plating film. A sufficient amount of the dispersing agent to exert the effect can be uniformly eutectoid, and the utilization factor of the dispersing agent can be greatly improved.

Further, in the dispersion plating method of the present invention, in the second step, a dispersant for causing eutectoid in the plating film is added to the plating solution, and the plating solution is stopped after stirring. Thereby, a method of depositing the settling dispersing material on the object to be plated can be adopted. In this case, the dispersant can be deposited on the object to be plated in a relatively uniform state in a short time and with low labor.

Further, in this case, the second step includes:
In the plating solution, a dispersing agent for causing eutectoid in the plating film is added, and after stirring the plating solution, the stirring is stopped, and at the same time, the plating in the third step can be performed. In this case, the plating time can be further reduced.

Further, the present invention can employ changing the strength of the magnetic field with time. In this case, the Lorentz force generated in the vicinity of the particles of the dispersing material also changes with time, so that the vortex generated around the particles of the dispersing material can change the state of rejecting other particles, and thus the eutectoid rate Can be controlled in the thickness direction of the plating film. With this method,
A film having an inclined structure in the thickness direction of the plating can be easily formed.

As the dispersion material in the present invention, alumina can be used. In this case, the hardness of the plating film can be increased, and a plating film having high wear resistance can be provided.

Further, a fibrous substance can be used as the dispersion material in the present invention. In this case, a vortex is generated by the Lorentz force generated in the vicinity of the fibrous substance, and the longitudinal direction of the fiber is aligned with the axial direction of the vortex, so that a dispersion plating film in which the fiber is oriented in the thickness direction is obtained. Can be.

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) In the dispersion plating method of Embodiment 1, a Watt bath (nickel sulfate 240
g / L, nickel chloride 45g / L, boric acid 30g / L)
Is used. A solution obtained by adding 20 g / L of α-alumina having an average particle diameter of 1 μm to this plating solution is used as a plating solution 1 for dispersion plating.
And put into plating bath. In this plating bath,
As shown in FIG. 1, the plating object 2 is extended in a horizontal direction,
A nickel counter electrode 3 is extended above it. The air pump 4 is operated to supply air from the stirring air nozzle 5 to the plating solution 1 for dispersion plating. After stirring, the stirring is stopped, and the precipitated α-alumina powder is deposited on the workpiece 2. While the magnetic field generator 6
The plating is performed by the external DC power supply 7 so that the current density becomes 800 A / m 2 while generating a magnetic field of four terraces so as to generate magnetic lines of force parallel to the direction of the current flowing in the plating solution (FIG. 2).

In the dispersion plating film thus obtained, a sufficient amount of α-alumina for uniformly improving the abrasion resistance was uniformly eutectoid.

On the other hand, when the strength of the magnetic field was less than 2 terraces, a normal plating film could not be obtained because only nickel was deposited in a lump.

(Embodiment 2) In the dispersion plating method of Embodiment 2, α-alumina having an average particle size of 5 μm is used as a dispersant.
The applied magnetic field was 7 T using a Watt bath to which 0 g / L was added. Other configurations are the same as those of the first embodiment.

As shown in FIG. 3, the plating film thus obtained has a eutectoid structure in which α-alumina 9 is arranged in a direction perpendicular to the plating object 8.

Embodiment 3 In the dispersion plating method of Embodiment 3, the intensity of the magnetic field was changed from 2 terraces to 7 terraces with time. Other configurations are the same as those of the first embodiment.

The α in the plating film thus obtained is
-As the eutectoid rate of alumina became closer to the plating surface, the eutectoid rate increased, and a plating film having a so-called gradient function could be obtained. In the third embodiment, by changing the manner of changing the strength of the magnetic field, it is possible to obtain dispersed plating films of various eutectoid forms.

Embodiment 4 In the dispersion plating method of Embodiment 4, a silicon carbide whisker having an average diameter of 0.2 μm is used as a dispersing material. Other components are the same as in the first embodiment.

The plating film obtained by the dispersion plating method of Embodiment 4 had a structure of a eutectoid form in which silicon carbide whiskers 11 were arranged in a direction perpendicular to the plating object 10 as shown in FIG.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a state before plating in a dispersion plating method according to a first embodiment.

FIG. 2 is an explanatory view showing a state during plating in the dispersion plating method of Embodiment 1.

FIG. 3 is a schematic diagram of a cross section of a plating film obtained by a dispersion plating method according to a second embodiment.

FIG. 4 is a schematic diagram of a cross section of a plating film obtained by a dispersion plating method according to a fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Plating solution 2 ... Plated object 3 ... Counter electrode 5 ... External power supply

Claims (8)

[Claims] 1. A first step of installing an object to be plated and a counter electrode in a plating solution; and a second step of contacting the object to be plated with a dispersant for causing eutectoid in a plating film. And a third step of passing a direct current from an external power supply such that the object to be plated is a cathode and passing a direct current from an external power supply so that the counter electrode is an anode, thereby depositing the plating metal and eutecting the dispersion material. A dispersion plating method, wherein plating is performed while applying a magnetic field such that magnetic lines of force are generated in a direction substantially parallel to a direction of a current flowing in the plating solution. In a first step, an object to be plated is extended in a plating solution in a substantially horizontal direction, and a counter electrode is installed above the object to be plated. 2. The dispersion plating method according to claim 1, wherein a dispersant for eutectoid deposition is deposited in the plating film. In the second step, a dispersing agent is added to the plating solution to cause eutectoid in the plating film, and the plating solution is agitated and then stopped. 3. The dispersion plating method according to claim 2, wherein a material is deposited on the object to be plated. In a second step, a dispersing agent for causing eutectoid in the plating film is added to the plating solution, and after stirring the plating solution, the stirring is stopped and at the same time, the plating in the third step is performed. The dispersion plating method according to claim 3, wherein the method is performed. 5. The dispersion plating method according to claim 1, wherein the intensity of the magnetic field is changed with time. 6. The dispersion plating method according to claim 1, wherein the dispersion material is alumina. 7. The dispersion plating method according to claim 1, wherein the dispersion material is a fibrous substance. 8. The dispersion plating method according to claim 1, wherein the dispersion material is a silicon carbide whisker.