JPH0246710A - Surface treatment for rare earth magnet material - Google Patents

Abstract

PURPOSE:To finish the grinding process and plating film formation of a magnet material by one time of operation by a method wherein rare earth magnet material and small metallic balls are mixed with one another in a vessel, the surface of the rare earth magnet material is degreased in a basic cleaning solution while the vessel is being turned to be immersed and electroplated in an acidic zinc chloride plating-bath, using the rare earth magnetic material and the small metallic balls as a cathode as well as the plating-bath as an anode. CONSTITUTION:The rare earth magnet material M is fed to a vessel 27 wherein multiple small metallic balls B are contained. The vessel 27 is immersed in a basic cleaning solution. The surface of the rare earth magnet M is degreased in degreasing vessel 2. Later, the vessel 27 is immersed in a washing vessel 3 to be washed. Next, the vessel 27 is pickled in a picking vessel 4 to be washed in another washing vessel 5. During these processes, the vessel 27 is being constantly turned at specific RPM by a moor 35 being driven. After grinding process such as chamfering corners, edges, etc., the vessel 27 is fed to a plating film formation vessel 6 to be electroplated using plating-bath as anode and the rare earth group magnet material M and the small balls B as cathode. In such a process, the plating-bath shall be the zinc chloride plating- bath.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for surface treatment of rare earth magnet materials, and more particularly to poles of small motors and videos.

Nd-Fe- to be used as magnetic means for magnetic heads of audio equipment, electrical, electronic parts, or other mechanical parts.
The present invention relates to a method for surface polishing and surface film formation of B-based magnet materials and Sm-Co-based magnet materials.

[Conventional technology]

As is well known, magnetic materials have been conventionally used as magnetic means in various electrical and electronic devices, mechanical parts, and the like. Among these magnet materials, Nd-Fe-B magnet materials (neodymium-iron-poron magnet materials) and Sm-Co magnet materials (sarum-cobalt magnet materials) have recently come to be used. These are usually made by cutting out the molded base material to create the magnet material, and then chamfering the corners and edges of the magnet material.
The threads are chamfered, the surface is polished, and then a film is formed on the surface to produce a magnetic product.

That is, both surface polishing and formation of a film on the surface are required in the surface treatment process. A typical reason for this is that if the magnet material has corners or edges, the material is brittle and will chip, resulting in poor quality, so the surface is polished to prevent this chipping. If the cut magnet material is left as it is, it will rust immediately upon exposure to air, and corrosion will progress. This may cause changes in the magnetic properties of the initially determined magnet material, dimensional changes, or a decrease in strength.

Therefore, a film is formed on the surface.

Therefore, in the past, chamfering and surface polishing and surface film formation have been carried out on magnet materials cut out from base materials. That is, first, corners and edges are chamfered by various mechanical polishing means, and after this step, a film is formed in a separate process.The method adopted for forming the film in this separate process is an aluminum vapor deposition process. Formation of a vapor-deposited film, formation of a coating film by painting with lacquer, etc., formation of a coating film by immersion in an epoxy resin, etc.

[Problem to be solved by the invention]

Although the above-mentioned conventional technology has a long track record of use and has several advantages, as a result of studies conducted by the present applicant, it has been found that it has the following disadvantages. That is, (1) the polishing process and the coating process are separate and cannot be performed in one operation; therefore, there is a limit to improving the efficiency of the surface treatment operation, and there is also a limit to reducing costs.

■After the polishing process, a separate coating process is carried out, so after polishing, the magnet material must be moved to coat it, making the work complicated, and due to the complexity, quality control is insufficient and results are lost. Become.

■The conventional film forming process is basically all dry process.
Equipment costs and operating costs are high, etc.

〔the purpose〕

Therefore, an object of the present invention is to provide (1) a manufacturing method in which polishing such as chamfering of a magnet material and formation of a plating film are performed in one operation. This provides a means for improving work efficiency and supplying magnet materials to the market at lower costs.

■Providing a manufacturing method that makes quality as uniform as possible.

- To provide a surface treatment method for magnet materials that can reduce equipment and operating costs.

In particular, (1) there is provided a surface treatment method that can improve polishing such as chamfering of the magnet materials and make the polishing precision of each magnet material uniform.

In addition, (1) the present invention provides a method for plating the above magnetic material with high current efficiency and forming a good plating film.

Another object of the present invention is to provide a manufacturing method in which the polishing causes as little contamination of the plating bath as possible, even though both polishing and plating film formation are performed in one step.

[Means for Solving the Problem] [Operation] In order to achieve the above object, the present invention has the following technical means.

That is, the present invention will be described as follows using the reference numerals in the accompanying drawings that correspond to the embodiments.

First, a rare earth magnet material M, for example, a Nd-Fe-B magnet material, is cut into a predetermined size from a molded base material.

A large number of Sm--Co magnet materials M and a large number of small metal balls B are mixed in the housing 27. In this case, small metal ball B
is preferably made of steel, but may be made of other metals, and when mixed in the container 27, it should be accommodated so that a space remains in the container, but it should be made of 1 of the total volume of the container 27.
An example can be given in which the space is accommodated so that /2 to 1/3 of the space remains, and the mixing ratio of the rare earth magnet material M and the small metal balls B can be selected as appropriate. On the other hand, an example can be given in which small metal balls are selected in the range of 0.8 to 1.3 and mixed.

After doing this, the container is then immersed in the basic detergent solution while rotating at a predetermined speed. Thereby, the surface of the rare earth magnet material M is degreased and then washed with water. Subsequently, pickling is performed and water washing is performed. Through these steps, the rare earth magnet material M and the small metal balls B are caused to flow within the container, that is, due to the presence of a space within the container 27, they are caused to flow and are rubbed against each other. As a result, the corners and edges of the rare earth magnet material M are chamfered. Moreover, each rare earth magnet material M rubs equally against the small metal ball B during the flow process within the container 27 as it rotates. Therefore, chamfering is performed uniformly. In particular, since the small metal ball B is a sphere as its name suggests, when focusing on the flowing phase, it enters between the rare earth magnet material M that is cut out and has corners, and its spherical surface allows the rare earth magnet material to Since the corners are plastically deformed, not only will the corners of the rare earth magnet material M not be chipped, but also be chamfered well.

Thereafter, it is immersed in an acidic zinc chloride plating bath, and electroplated using the rare earth magnet material and small metal balls as cathodes and the acidic zinc chloride plating bath as an anode. In this case, the cathode terminal faces into the above-mentioned inclusions. As a result, a plating film is formed on the surface of the rare earth magnet material M. That is, a plating film is formed by this wet method on the surface of the rare earth magnet material M whose surface has been polished such as chamfering up to the above steps, but as described above, small metal balls B are is accommodated, and the cathode terminals 41 and 42 also come into contact with this small metal ball B. More specifically, the rare earth magnet material M has a cut-out angular shape, and if only this angular shape is used, the contact efficiency with the rare earth magnet material M of the cathode terminals 41 and 42 facing inside the container 27 will be affected. There is a certain loss due to its geometrical shape, but if small metal balls B are mixed, as the name suggests, they are spheres, so the contact efficiency of the cathode terminals 41 and 42 with respect to them and , the contact properties are much better. A current flows through each rare earth magnet material M through this small metal ball B, but since the small metal ball B is a sphere here as well, the contact efficiency and the contact property with respect to the angular rare earth magnet material M are as follows. and ultimately good contact efficiency and contactability.

That is, the current efficiency for plating is good, and a plating film can be formed well. Similarly to the polishing described above, the small metal balls B are inserted equally between the rare earth magnet materials M, and the distribution of the mixture is uniform, so that the current flows uniformly to each rare earth magnet material.
A uniform plating film is formed. In addition, the cathode terminal facing into the container is formed as a free end so as to be able to move freely in accordance with the flow of the inclusions in the container as the container rotates.

Therefore, the above plating bath contains ordinary simple Zn salt and hydrated Zn.
An acidic zinc chloride plating bath containing ions as a main component may be used, but a weakly acidic zinc chloride plating bath containing a Zn ammonium complex as a main component may also be used.

Since this is a zinc oxide plating bath, wastewater treatment can be done with a minimum amount of work, and there is no need for wastewater treatment equipment such as cyanide, which causes pollution.The electroconductivity of the liquid is good, so the bath voltage is low and the power consumption is low. It will save you money. In addition, even with the same zinc chloride plating bath, if it is neutral, the range of conditions under which bright plating can be obtained is narrow, but since it is an acidic bath, there are relatively few restrictions.
After the plating film is formed in this way, it is washed with water,
Next, take out the rare earth magnet material from the group of small metal balls.
This allows both polishing of rare earth magnet material and formation of a no-burn coating in one operation.

〔Example〕

Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the surface treatment apparatus A of the embodiment will be explained. This surface treatment apparatus A has a treatment tank main body C in which various types are connected in series laterally. That is, as shown in FIGS. 2 and 3, from left to right, there is a storage part l for rare earth magnet material M, a degreasing tank 2, a washing tank 3, a pickling tank 4, a washing tank 5, and a plating film formation. A tank 6, a washing tank 7, and a take-out section 8 for rare earth magnet material M are formed.

The above-mentioned inner container part 1 and removal part 8 are spaces for putting rare earth magnet material M into the container and discharging it from there, which will be described later, so they can simply be used as spaces open to the outside where the worker stands. However, other tanks have a so-called bottomed top opening shape.

A drain plug (not shown) is provided at the bottom of each type.

Next, the reference numeral indicates a container conveying device, which will be described later, and is composed of left and right side plates 9.10, a top plate 11 etc. that connects these left and right side plates 9.10, and the left and right side plates 9.10.
Wheel axles 12 and 13 are passed between the front and back.

A wheel 14 is attached to each end of each wheel axle 12,13.

The four wheels 14 run on rails 15 provided on the upper surface of both side edges of the processing tank body C.

The wheels 14 are driven by a motor 1B, a chain 17. 18
This is carried out by drive and power transmission means such as. Further, an air cylinder 18 is attached to the top plate 11, and a piston 20 thereof is configured to move forward and backward downward, and a plate 21 is horizontally installed at the tip of the air cylinder 18.

That is, the air cylinder 18 is driven to move the piston 20 up and down, thereby causing the plate 21 to move up and down. In order to make the above vertical movement smooth, vertical movement guides 22 and 23 are provided, and container locking pins 24, which will be described later, are provided at both ends of the plate 21.
Next, symbol E indicates a container setting device, and the left and right side plates 25.2
It has a shape in which a bar 26' is arranged between the left and right side plates 25
．． A container 27 is rotatably arranged between 28.

Namely, container 2? In this example, it has a hexagonal cylindrical shape, has an opening 28 formed in its circumferential surface, and has a removable lid 28 in part. A shaft 31 is passed between one side plate 30 of the container 27 itself and the left side plate 25 of the container setting device E, and a shaft 34 is passed between the other side plate 32 of the container 27 itself and the right side plate 28 of the container setting device E. ing.

In addition, this container setting device E is equipped with a motor 35, and a gear plate 3B connected to the output shaft of the motor 35 meshes with another gear plate 38 via a gear plate 37. It is fixed to one side plate 32 of the container 27. Therefore, the rotation of the motor 35 is caused by the gear plates 3B, 37.
Container 2 through 38? The container 27 is transferred to the shaft 31.
It rotates slowly at a predetermined rotational speed with 34 as the center of rotation. Of course, other methods of rotation may be used.

Now, the left and right side plates 25 configuring this container setting device E.
A locking hook 39, 40 is attached to the upper part of the container 28, and by hooking this to the locking bin 24 of the conveying device, the container setting device, that is, the container 27 is suspended in various objects, and the container 27 is suspended in various places. It is configured to move up and down in a closed state.

Furthermore, cathode terminals 41, 42 face the container 27. That is, through the center of the shaft 31.34 an insulated cathode terminal 41.42 is located in the container, and each cathode terminal 41
．． 42 terminals are set as free ends and are free. A surface treatment method according to an example of the present invention using such a surface treatment apparatus will be described below with reference to FIG. First, a basic cleaning agent is placed in the degreasing tank 2. Further, the pickling tank 4 contains hydrochloric acid and 10% nonionic surfactant added thereto. Further, the plating film forming tank 6 contains a weakly ugly zinc chloride plating bath. Additives are added to this plating bath as necessary. For example, additives as brightener carriers, buffers, activators, etc. An example of a more specific bath composition and working conditions is shown in Table 1 below.

The washing tanks 3, 5.7 each contain water.

Now, in such a state, first, the conveying device is positioned over the rare earth magnet material storage section l. Then, the lid 29 of the container 27 is opened and a large number of rare earth magnet materials M are put into the container 27. Since a large number of small metal balls B are housed in the container 27, the metal balls B are mixed therewith. Of course, they may be mixed and then housed in the container 27. In these cases, the rare earth magnet material has an angular shape cut out from the molded base material, but its size varies depending on the application. - For example, one width is 10 m/m, the depth is 10 m/m, and the thickness is 5 to 7 ffi/11. On the other hand, the diameter of the small metal ball, for example, the steel ball B, can be of the order of 6 m/m, for example, although various diameters can be applied as long as they are small balls. In addition, when the inclusions are accommodated in the container 27, they are accommodated in such a way that a space of 1/2 to 1/3 of the total volume remains in the container 27.

This is because the subsequent rotation of the container 27 causes these mixed substances to flow within the container. In addition, an example can be given in which the volume ratio of the rare earth magnet material M and the small metal ball B is about 1 to 1.3 for the former to 1 for the latter.

After this, the piston 20 of the cylinder 18 of the m-feeding device is raised to position the container 27 at its upper limit, and then the motor 16 of the conveying device is driven to drive the wheels 14.
The entire conveying device is positioned above the degreasing tank 2. Then, the piston 20 is lowered to position the container 27 at its lower limit of movement. That is, the container 27 is immersed in a basic cleaning material. The traveling S of these conveying devices, their stopping, and the vertical movement of the piston 20 are executed by known control means. Now,
In the degreasing bath 2, the surface of the rare earth magnet material M is degreased for, for example, 5 to 10 minutes. From then on,
Due to the movement of the conveying device and the operation of the piston 20, the container 2
7 is immersed in the next stage water washing tank 3 and washed with water for about 1 minute, for example.
It is pickled for a minute, and then washed with water for about 1 minute in a washing tank 5 at the next stage.

During these processes, the container 27 is constantly rotated slowly at a constant speed by the rotation of the motor 35. That is, the rotational force of the motor 35 is transmitted to the gear plates 3B, 37.38, and the container 27 is slowly rotated about the shaft 31.34. As a result, the rare earth magnet material M and the small metal balls B flow in the container and rub against each other in the wave process as shown in the conceptual diagram of FIG. Then, due to friction, as shown in the conceptual diagram of FIG. 8, the corner of the rare earth magnet material M
The edges are plastically deformed and chamfered.

The characteristics of this polishing process are as follows.

In other words, each rare earth magnet material M is attached to the container 27 as it rotates.
In the process of internal flow, the small spheres equally enter into the metal ball B. This is because the small metal balls B are spheres as the name suggests, and therefore enter the group of rare earth magnet materials M in an even distribution. Therefore, each rare earth magnet material is chamfered uniformly. Furthermore, since friction between the rare earth magnet materials M may cause chipping, this problem is also prevented. In addition, since the plastic deformation is mainly caused by the small metal balls B, no liquid stains occur.

After polishing such as chamfering the corners and edges, the container 27 is sent to the plating film forming tank 6. Here, the mold plating is carried out for, for example, 30 minutes. That is, wet electroplating is performed using the plating bath as an anode and the rare earth magnet material M and small metal balls B as cathodes. For example, the plating thickness is 0.00
One example is one with a fat content of about 7 to 0.009+s. The features here are as follows.

That is, the rare earth magnet material M has a cut-out angular shape, and when only this angular material is used, the cathode terminal 4 facing into the container 27
There is a certain loss in the contact efficiency with the rare earth magnet material M of 1.42 due to its geometric shape, but if small metal balls B are mixed, as the name suggests, it is a sphere, so The contact efficiency of the cathode terminal with these small metal balls B and the rare earth magnet material M is improved.

In other words, the electrolyte efficiency is improved and plating is carried out efficiently. The conceptual diagram in FIG. 9 shows how electricity flows from the cathode terminal 42 to the small metal ball B, and then to the rare earth magnet material M. Of course, in the phase of the flow process, it may be transmitted from the cathode terminal to the rare earth magnet material M, and then transmitted to other rare earth magnet materials M via the small metal ball B.

Since the small metal balls B are uniformly distributed on the surface, the electrical conduction described above is also carried out uniformly. In addition, since the contact state between the small metal ball B and the rare earth magnet material M is point contact,
The current density at the contact points of each part is equal, and in this sense, the plating becomes uniform. In this way, surface polishing such as chamfering and formation of a plating film can be performed in one step.

Since the above-mentioned plating bath is a zinc chloride plating bath, only the neutralization precipitation method is required for wastewater treatment.Since cyanide is not used, there is no need for wastewater treatment equipment to avoid pollution, and the bath has good conductivity. Low voltage saves power. In addition, since the plating speed is relatively high and it is an acidic bath, the conditions for obtaining bright plating are not limited.

The rare earth magnet material M whose surface has been treated in this way is discharged from the group of 8 small metal balls in the extraction section 8.

〔effect〕

As detailed above, according to the present invention, (1) the chamfered surface of a rare earth magnet material can be polished and a plating film can be formed in one operation;

■And, as a result of the - work, the surface treatment becomes uniform.

■Equipment and operating costs for this purpose are also low.

■ Surface polishing such as chamfering can be performed well, and the polishing precision can be made uniform.

■The plating film can be formed with high current efficiency, and the plating film can be made uniform.

It offers various practical advantages.

[Brief explanation of the drawing]

The accompanying drawings show embodiments of the present invention; FIG. 1 is a process explanatory diagram, FIG. 2 is a plan view of the surface treatment apparatus, FIG. 3 is a side view including a partial cross section, FIG. 4 is a cross sectional view, and FIG. Fig. 5 is a front view of the container setting device, Fig. 6 is a side view of the container setting device, Fig. 7 is a conceptual diagram of the polishing process of rare earth magnet material, and Fig. 8 is a corner and edge of the rare earth magnet material made of small metal balls. FIG. 9 is a conceptual diagram showing a place where the ball B is corrugated and chamfered, and FIG. 9 is a conceptual diagram of the process of forming a plating film on a rare earth magnet/material. In the figure, M is a rare earth magnet material and B is a small metal ball. ■ is a rare earth magnet material storage part, 2 is a degreasing tank, 3 is a water washing tank, 4
5 is a pickling paddle, 5 is a washing tank, 61 is a plating film forming tank, and 7 is a pickling paddle.
8 is a washing tank, and 8 is a rare earth magnet material extraction section.

Claims (6)

[Claims] (1) In a surface treatment method for rare earth magnet material M, in which the surface of rare earth magnet material M cut out from a molded base material is polished and a film is formed on the surface; a large number of the rare earth magnet materials M are placed in a container 27; Contain,
First, they are immersed in a basic detergent to prepare the rare earth magnet material M.
The surface of the is degreased, then washed with water, then pickled, then washed with water, and then immersed in an acidic zinc chloride plating bath, using the rare earth magnet material as a cathode, and using the acidic zinc chloride plating as a cathode. A plating film is formed on the surface of the rare earth magnet material M by electroplating using the bath as an anode, which is then washed with water, and a large number of small metal balls are placed in the container 27 containing the rare earth magnet material M. The above steps are carried out with a large number of rare earth magnet materials M mixed with a large number of small metal balls B, and the polishing of the surface of the rare earth magnet material M is carried out in the container 27 in each of the above steps. The rare earth magnet material M and the small metal balls B are transferred to the rotating container 27 by the rotation of
Rare earth magnet material M and metal ball B are made to flow inside.
The formation of a plating film on the surface of the rare earth magnet material M is carried out by causing the corners and edges of the rare earth magnet material M to be plastically deformed and chamfered by making them rub against each other using small metal balls B, and forming a plating film on the surface of the rare earth magnet material M. The rotation of the container 27 during the immersion process in the acidic zinc chloride plating bath causes the container 27 to
A method for surface treatment of a rare earth magnet material, characterized in that the cathode terminals 41 and 42 facing inside are brought into contact not only with the rare earth magnet material M but also with a small metal ball B. (2) The method for surface treatment of a rare earth magnet material according to claim 1, wherein the rare earth magnet material M is a Nd-Fe-B based magnet material. (3) The method for surface treatment of a rare earth magnet material according to claim 1, wherein the rare earth magnet material M is an Sm-Co magnet material. (4) The method for surface treatment of rare earth magnet materials according to claim 1, 2 or 3, wherein the small metal balls B are steel balls. (5) When the mixture of rare earth magnet material M and small metal balls B is housed in the rotating container 27, 1/2 to 1/3 of the total volume of the rotating container 27 is a space. The mixture is housed in the rotating container 27 so that the rare earth magnet material M and the small metal balls B are mixed in a volume ratio of 0.0.
The surface treatment method for rare earth magnet material according to claim 1, 2, 3, or 4, characterized in that the surface treatment method is carried out by selecting one of the following: 8 to 1.3. (6) A plurality of cathode terminals 41 and 42 facing into the rotating container 27 are provided, each of which is configured as a free end so as to be freely displaceable as the rotating container 27 rotates. Paragraph 1, Paragraph 2, Paragraph 3, Paragraph 4 or Paragraph 5
2. Surface treatment method for rare earth magnet material described in Section 1.