JP2002158105A - Magnet and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnet which can reduce dispersion in bonding strength, realize large bonding strength and realize effective bonding operation by effectively eliminating setting defect of adhesive which is inactive to a nickel plating film. SOLUTION: A magnet (2) has an R-TM-B rare earth magnet body (4) comprising R (R is one or more kinds of rare earth elements including Y), TM (TM is an Fe-base transition element) and B, a protection film (6) comprising a nickel plating film formed in a surface of the magnet body, and a 0.1 μm or less-thick phosphoric acid film (8) formed through phosphoric acid treatment by using treatment liquid containing no fluoride in a surface of the protection film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnet and a method for manufacturing the same.

[0002]

2. Description of the Related Art Nd-Fe-B magnets have high magnetic properties, are rich in Fe, which is a main material, and are inexpensive.
In recent years, rare-earth magnets have become the mainstream in place of Sm-Co-based magnets because Nd, which is a rare earth, is resource-efficient and inexpensive compared to Sm, and supply is unstable and does not use expensive Co. It has become.

[0003] Nd-Fe-B-based magnets have been subjected to various surface treatments because they have the drawback that if they are used as they are, they are much more likely to corrode than ordinary steel materials.

[0004] Nickel plating, which is inexpensive and has excellent corrosion resistance, is widely used for the rust prevention treatment of Nd-Fe-B magnets. Then, another member is fixed on the nickel plating on the magnet surface via an adhesive to be used. Epoxy adhesives and anaerobic acrylic adhesives are often used for this type of adhesive, especially anaerobic acrylic adhesives have good workability and low curing temperature, so there is little thermal demagnetization. From
It is often chosen in preference.

[0005] However, the anaerobic acrylic adhesive has a high activity with respect to iron and copper, and as a result, reacts quickly, whereas when the adherend is nickel, the reactivity is poor. There is. When bonding a reaction-inactive adherend represented by nickel, the surface to be bonded is treated with an activator (primer). However, in the case of a small object, the workability is significantly reduced and the advantage of an anaerobic acrylic adhesive is obtained. Not only can not be used, but also increases the cost in the bonding process.

By the way, zinc phosphate treatment is widely used as a base treatment for painting steel or aluminum. It is known that when zinc phosphate treatment is applied to steel or aluminum, phosphate crystals precipitate as a film on the surface thereof, and the adhesion of the coating film is improved.

[0007]

However, when the technology used for the undercoat treatment of steel or aluminum is applied to nickel plating as it is, the corrosion resistance of nickel is excellent, so that the reaction in the treatment solution is sufficient. No phosphate crystals were deposited on the surface.

In Japanese Patent Application Laid-Open No. 6-318512, after the surface of the nickel plating film formed on the surface of the Nd—Fe—B magnet body is activated in advance using an acid containing a fluoride, it is further activated. Treating with a zinc phosphate solution containing a fluoride, the surface of the nickel plating film has a thickness of 0.1 to 1
A method is disclosed in which a zinc phosphate coating of 0 μm is formed, and the adhesion of the nickel plating film surface is improved by the effect of the zinc phosphate coating. Here, since the fluoride forcibly dissolves and activates the nickel-plated surface, zinc phosphate crystals are formed as a film on the nickel plating, and the adhesive strength is improved.

[0009] However, according to the method described in the above publication, the adhesive strength may greatly change depending on the state of pretreatment (activation treatment) with an acid containing fluoride.
There is also a disadvantage that it is difficult to control the thickness of the zinc phosphate coating, and it has been difficult to obtain a stable adhesive strength at a production level. For this reason, there has been a demand for the development of a technology capable of obtaining a stable bonding strength at a production level and realizing an efficient bonding operation.

[0010] An object of the present invention is to effectively eliminate poor curing of an adhesive that is inactive to a nickel plating film, to reduce variation in adhesive strength, and to obtain large adhesive strength. An object of the present invention is to provide a magnet capable of realizing an efficient bonding operation. Another object of the present invention is to provide a method for manufacturing a magnet that can efficiently manufacture such a magnet.

[0011]

Means for Solving the Problems The present inventors performed a phosphate treatment on a surface of a nickel plating film formed on the surface of a magnet main body using a treatment liquid having a specific composition, thereby obtaining the nickel plating film. The thickness of the phosphate film formed on the surface is easily controlled, and as a result, it is possible to stably improve the adhesion of the nickel plating film surface at the production level, and realize that the efficiency of the bonding operation can be improved. The present invention has been completed.

The method for manufacturing a magnet, that is, the method for manufacturing a magnet according to the present invention comprises the steps of: electroplating a surface of a magnet main body containing a rare earth element to form a protective film made of a nickel plating film; Performing a phosphate treatment on the surface of the substrate with a treatment solution containing no fluoride to form a phosphate film.

[0013] Preferably, the pH of the treatment liquid is 4 or less.

[0014] Preferably, the treatment temperature of the phosphating treatment is 20 to 50 ° C.

Preferably, the treatment liquid contains nitrate ions at a ratio of 2 to 30 g / l.

Preferably, before forming the protective film,
The method further includes a first pretreatment step of performing a degreasing treatment on the surface of the magnet main body using an alkaline solution, performing chemical etching with an acid, and cleaning the surface of the magnet main body.

Preferably, before forming the phosphate film, the method further comprises a second pretreatment step of performing a degreasing treatment on the surface of the protective film using an alkaline solution and washing the surface.

As an example of alkali, NaOH is inexpensive, easily available, and has a high degreasing effect. Therefore, it is preferable to use an alkaline solution containing NaOH as a main component.

Preferably, after forming the phosphate coating, the magnet body is dipped in alcohol and air-dried.

Magnet The magnet according to the present invention comprises a magnet main body containing a rare earth element, a protection film made of a nickel plating film formed on the surface of the magnet main body, and a 0.1 μm film formed on the surface of the protection film.
A phosphate coating having a thickness of less than.

Preferably, the phosphate film is formed by phosphate treatment using a treatment solution containing no fluoride.

Preferably, there is further provided an underlayer mainly composed of copper, formed between the magnet main body and the protective film.

Common Items Examples of the phosphate include tin phosphate, iron phosphate, manganese phosphate, zinc phosphate, calcium zinc phosphate and the like.

The magnet body is not particularly limited as long as it contains a rare earth element in the present invention.
R is at least one kind of rare earth element including Y), TM (however,
TM is a transition element mainly composed of Fe) and R containing B
The effect is particularly large in the case of a TM-B-based rare earth magnet. A typical example of the R-TM-B-based rare earth magnet is Nd-Fe
-B-based rare earth magnet.

[0025]

In the magnet according to the present invention, the internal stress applied to the phosphate coating can be reduced by forming the phosphate coating as extremely thin as less than 0.1 μm on the surface of the protective film made of the nickel plating film. For this reason, even if various adhesives, such as an anaerobic acrylic adhesive, are adhered on this ultra-thin phosphate film, the possibility that the phosphate film is broken is extremely low. On the other hand, even if the thickness of the phosphate film is less than 0.1 μm, it can be expected that the film is formed uniformly without being destroyed and stable adhesive strength is obtained. That is, in the present invention, by forming the thickness of the phosphate coating extremely thin, it is possible to prevent the phosphate coating from being broken by internal stress and to ensure uniform thickness, and as a result, the nickel plating film Thus, it is possible to effectively suppress the inhibition of curing of various reaction-inactive adhesives (for example, an anaerobic acrylic adhesive), thereby realizing an efficient bonding operation.

In the method of manufacturing a magnet according to the present invention, when a phosphate film is formed on the surface of a protective film made of a nickel plating film formed on the surface of a magnet main body containing a rare earth element, a fluoride-free treatment is performed. Phosphate treatment is performed using the solution. Therefore, it is easy to control the thickness of the phosphate film, and a phosphate film having a thickness of less than 0.1 μm can be stably formed at a production level.

The specific application of the magnet according to the present invention is not particularly limited, and examples thereof include various types of industrial rotary equipment, consumer rotary equipment, and optical pickup devices.

Examples of the industrial rotary equipment include various motors used for automobiles and motorcycles; drive systems for machine tools. For consumer rotary equipment, VTR, C
Various motors used for D, MD, DVD, cassette stereo, etc .; motors of OA equipment (computers, printers, copiers, etc.) are exemplified.

The optical pickup device is for recording / reproducing information on / from an optical disk as a recording medium. Generally, the optical pickup device has an objective lens driving device for moving an objective lens in a tracking direction or a focusing direction of the optical disk, and a mounting table. An optical system block that is provided with a light source, a light receiving unit, and the like, projects laser light onto an optical disk via an objective lens, and detects reflected light thereof. When the magnet of the present invention is used in an optical pickup device, the magnet is used in a magnetic circuit that is a component of the objective lens driving device.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a schematic sectional view showing a permanent magnet according to an embodiment of the present invention, and FIG.
9 is a graph showing a relationship between a curing time and an adhesive strength for each of the permanent magnet samples of Comparative Example 1 and Comparative Example 5.

As shown in the permanent magnet Figure 1, the permanent magnet 2 according to the present embodiment, the protective film 6 on the surface of the magnet body 4 is formed. On the surface of the protective film 6, a phosphate film 8 is formed.

The magnet body magnet body 4, in this embodiment, R (wherein, R is one or more rare earth elements including Y), TM (although, TM is F
R-TM- containing a transition element whose main component is e) and B
It is a B-based rare earth magnet.

The contents of R, TM and B are 5.5 atomic% ≦ R ≦ 30 atomic%, 42 atomic% ≦ TM ≦ 90 atomic%,
It is preferable that 2 atomic% ≦ B ≦ 28 atomic%.

As the rare earth element R, Nd, Pr, H
at least one of o and Tb, or L
a, Sm, Ce, Gd, Er, Eu, Pm, Tm, Y
Those containing at least one of b and Y are preferred.

When two or more elements are used as R, a mixture such as misch metal can be used as a raw material.

The R content is preferably 5.5 to 30 atomic%. When the content of R is too small, the crystal structure of the magnet becomes a cubic structure having the same structure as that of α-iron, so that a high coercive force (iHc) cannot be obtained. And the residual magnetic flux density (Br) decreases.

The content of TM is preferably from 42 to 90 atomic%. If the content of TM is too small, Br decreases, and if it is too large, iHc decreases. By substituting a part of Fe with Co, the temperature characteristics can be improved without impairing the magnetic characteristics. In this case, if the amount of Co substitution exceeds 50% of Fe, the magnetic properties deteriorate, so the amount of Co substitution is preferably set to 50% or less.

The B content is preferably from 2 to 28 atomic%. If the B content is too small, the crystal structure of the magnet becomes a rhombohedral structure, resulting in insufficient iHc. If the B content is too large, the B-rich nonmagnetic phase increases, and the Br decreases.

Further, in addition to R, TM, and B, Ni, Si, Al, Cu, Ca and the like may be contained as unavoidable impurities at 3 atomic% or less of the whole.

Further, by replacing a part of B with one or more of C, P, S, and Cu, it is possible to improve productivity and reduce costs. In this case, the substitution amount is preferably at most 4 atomic%. In order to improve coercive force, improve productivity, and reduce costs, Al, T
i, V, Cr, Mn, Bi, Nb, Ta, Mo, W, S
One or more of b, Ge, Sn, Zr, Ni, Si, Hf and the like may be added. In this case, it is preferable that the total amount be 10 atomic% or less.

The magnet main body 4 in this embodiment has a main phase having a substantially tetragonal crystal structure. The particle size of the main phase is preferably about 1 to 100 μm. And it usually contains 1 to 50% of a non-magnetic phase by volume ratio.

Protective Film The protective film 6 is composed of a plating film formed by an electroplating method. The plating film preferably contains nickel as a main component. By using nickel as a main component, the strength of the protective film 6 can be increased and an excellent rust prevention effect can be exhibited.

As the protective film 6, rack plating or barrel plating is appropriately selected according to the size and shape of the magnet main body 4. The protective film 6 made of a nickel plating film formed by the electroplating method needs to be defect-free in order to obtain excellent corrosion resistance.
Is preferably 10 to 30 μm, more preferably 10 to 30 μm.
It is about 20 μm.

The adhesiveness does not change significantly depending on the type of the nickel plating film constituting the protective film 6.
However, in order to reduce the concentration of stress applied to the interface between the magnet main body 4 and the protective film 6 and further increase the adhesive strength, a base layer (not shown) is provided between the magnet main body 4 and the protective film 6.
It is preferable to further have The underlayer preferably contains Cu as a main component. In the case where such an underlayer is provided, when a load is applied to the magnet body after bonding, it has a function of suppressing concentration of stress at one portion of the interface with the magnet body because Cu is soft, The bonding strength is improved. The thickness of the underlayer is not particularly limited, but is preferably about 5 to 10 μm.

Phosphate Coating The phosphate coating 8 is formed by a phosphate treatment. In this embodiment, the thickness T2 of the phosphate coating 8 is 0.1 μm.
m, preferably 0.01 μm or less. When the phosphate is laminated thickly, the internal stress applied to the phosphate coating 8 increases, and when the adhesion test is performed, the phosphate coating 8 is easily broken. Further, depending on the curing conditions of the adhesive, the water of crystallization of the phosphate evaporates, and cracks may occur in the phosphate coating 8. By setting the thickness T2 of the coating 8 to less than 0.1 μm, the phosphate coating 8 has a crystal structure at a level that cannot be observed with a microscope, and the problem caused by the thick coating is eliminated.

The effect of improving the adhesive strength exerted by the phosphate film 8, particularly, the curability of the anaerobic acrylic adhesive, is improved when the phosphate film 8 is present on the surface of the protective film 6. The lower limit of the thickness T2 of the phosphate coating 8 is:
It is about 0.001 μm, preferably about 0.005 μm.

The manufacturing method of a permanent magnet Next, an example of a manufacturing method of a permanent magnet 2 according to the present embodiment.

(1) First, a magnet main body is manufactured. It is preferable to use a powder metallurgy method for manufacturing the magnet main body 4.
The manufacture of the magnet main body 4 by the powder metallurgy method is performed as follows.

First, an alloy having a desired composition is manufactured by using various alloy manufacturing processes such as a casting method and a strip casting method. Next, the obtained alloy is roughly pulverized to a particle size of about 10 to 100 μm using a coarse pulverizer such as a jaw crusher, a brown mill, a stamp mill, and the like. 5-5
Finely pulverize to a particle size of about μm. Next, the obtained powder is molded preferably in a magnetic field. The magnetic field strength during molding is preferably at least 600 kA / m. The molding pressure is preferably about 0.5 to ⁵ ton / cm ² . Next, the obtained molded body is subjected to 1000 to 1200 ° C.
And quenched for 0.5 to 10 hours. The atmosphere during sintering is preferably an inert gas such as Ar gas.
After that, it is preferably 500 to 90 in an inert gas atmosphere.
Heat treatment (aging treatment) is performed at 0 ° C. for 1 to 5 hours.

The manufactured magnet main body 4 has, for example, R = N
In the case of d, it is known that it has particularly excellent magnetic properties, but has a negative expansion coefficient in a direction perpendicular to the C axis.

(2) Next, the surface of the magnet body 4 obtained is degreased, and then chemically etched with an acid to clean the surface of the magnet body 4 (first pretreatment). This first pretreatment is an optional treatment in the present invention, but by performing a degreasing treatment, the surface of the magnet main body 4 can be stained,
There is a merit that the protective film 6 can be reliably formed. Before the degreasing treatment, barrel polishing may be performed to remove burrs and the like on the surface of the magnet main body 4.

The degreasing solution used in the degreasing treatment is not particularly limited as long as it is used for ordinary steel. Generally, NaOH is a main component, and other additives are not specified.

It is preferable to use nitric acid as the acid used in the chemical etching. When plating a general steel material, a non-oxidizing acid such as hydrochloric acid or sulfuric acid is often used. However, when the magnet body contains a rare earth element, such as the magnet body 4 in the present embodiment, when the treatment is performed using these acids, hydrogen generated by the acids is occluded on the surface of the magnet body, The storage site becomes brittle and a large amount of undissolved powder is generated. Since this powdery undissolved substance causes surface roughness, defects and poor adhesion after the surface treatment, it is preferable that the above-mentioned non-oxidizing acid is not contained in the chemical etching treatment solution. Therefore, it is preferable to use nitric acid, which is an oxidizing acid that generates less hydrogen.Also, aldonic acid or a salt thereof is simultaneously contained. Is more preferable because the adhesion of the film is improved. In addition, such an improvement in adhesiveness is selectively realized by aldonic acid or a salt thereof, and is not realized by another organic acid such as citric acid or tartaric acid.

The amount of dissolution of the surface of the magnet body 4 by such pretreatment is preferably 5 μm or more, preferably 10 to 15 μm in average thickness from the surface. If the amount of dissolution is too small, the deteriorated layer and the oxidized layer due to the processing of the surface of the magnet main body cannot be completely removed, so that a protective film 6 described later is not normally formed on the surface of the magnet main body 4 and deteriorates the corrosion resistance. I will.

The nitric acid concentration of the processing solution used for the pretreatment is as follows:
It is preferably at most 1 normal, particularly preferably at most 0.5 normal. If the nitric acid concentration is too high, the dissolution rate of the magnet main body 4 is extremely high, and it is difficult to control the dissolution amount. In particular, in large-scale processing such as barrel processing, the dispersion becomes large, and the dimensional accuracy of the product cannot be maintained. On the other hand, if the nitric acid concentration is too low, the dissolved amount will be insufficient. For this reason, the nitric acid concentration is desirably 1 normal or less, particularly preferably 0.5 to 0.05 normal or less. The amount of Fe dissolved at the end of the treatment is 1 to 10 g /
about l.

In order to completely remove a small amount of undissolved substances and residual acid components from the surface of the pretreated magnet body 4, it is preferable to carry out cleaning using ultrasonic waves. This ultrasonic cleaning is preferably performed in ion-exchanged water in which the chlorine ions that generate rust on the surface of the magnet main body 4 are extremely small.
Further, similar water washing may be performed before and after the ultrasonic cleaning and in each step of the pretreatment as needed.

(3) Next, the pretreated magnet body 4
A protective film 6 is formed on the surface of the substrate by electroplating. By forming the protective film 6 using the electroplating method, the protective film 6 that is a high-performance corrosion-resistant film can be formed at low cost. Examples of the plating bath used for the electroplating of Ni include a Watt bath containing no nickel chloride (that is, containing nickel sulfate and boric acid as main components), a sulfamic acid bath, a borofluoride bath, and a nickel bromide bath. However, in this case, it is preferable to replenish the bath with nickel ions because the dissolution of the anode is reduced. The nickel ions are preferably replenished as a solution of nickel sulfate or nickel bromide.

In addition, before forming the protective film 6 on the surface of the magnet body 4 after the pretreatment, for example, when forming an underlayer containing Cu as a main component (not shown), the surface of the magnet body 4 may be formed. PH to prevent the substitutional precipitation of Cu
The treatment is preferably performed in a weak alkaline bath of 7 to 10.
In the case of forming the underlayer containing Cu as a main component, the above-mentioned nickel plating bath is not limited to the above-described example, and the protective film 6 made of a nickel plating film is formed in a bath containing nickel chloride. Even this does not impair the corrosion resistance. That is, in this case, the protective film 6 may be formed using a bath containing nickel chloride.

(4) Next, after the surface of the protective film 6 is degreased, the surface is sufficiently cleaned with pure water (second pretreatment).
This second pretreatment is also optional in the present invention, but by performing a degreasing treatment, dirt (organic substances such as a brightener) adhered to the surface of the protective film 6 can be removed, and the phosphate film 8 can be reliably formed. There is a merit that can be formed.

The degreasing solution used in the degreasing treatment is not particularly limited as long as it can remove organic substances, but the use of an alkaline solution is the most effective and preferable. The alkaline solution only needs to be used for ordinary iron and steel containing NaOH as a main component, and other additives are not specified.

(5) Next, a phosphate treatment is performed on the surface of the protective film 6 to form a phosphate coating 8. Specifically, the magnet main body 4 on which the protective film 6 is formed is immersed in a phosphate bath adjusted to a predetermined concentration and temperature, and a phosphate film 8 is formed on the surface of the protective film 6.

Examples of the treatment liquid used for the phosphate treatment include a tin phosphate treatment liquid, an iron phosphate treatment liquid, a manganese phosphate treatment liquid, a zinc phosphate treatment liquid, and a zinc calcium phosphate treatment liquid. If any of these treatment solutions is used, an adhesion effect is imparted to the protective film 6 made of a nickel plating film. The components of the zinc phosphate treatment liquid as an example of these are not particularly limited, and include zinc ions,
Examples thereof include a phosphate ion and a nitrate ion. The preferred concentration of each of these ions is zinc ion: 0.4 to 3.0.
g / l, especially 0.5 to 2.0 g / l, phosphate ion: 5
-40 g / l, especially 7-30 g / l, nitrate ion: 2
30 g / l, especially 2 to 10 g / l.

When the zinc ion concentration is too low, there is a tendency that a uniform phosphate film 8 cannot be formed on the surface of the protective film 6. On the other hand, if the zinc ion concentration is too high, the thickness T2 of the phosphate coating 8 tends to be too large, and the adhesive strength tends to be insufficient.

If the phosphate ion concentration is too low, there is a tendency that a uniform phosphate coating 8 cannot be formed. On the other hand, if the phosphate ion concentration is too high, improvement in the effect of forming the phosphate coating 8 cannot be expected.

The nitrate ion is added as an accelerator for forming the phosphate film 8 on the protective film 6 made of a nickel plating film. If the nitrate ion concentration is too low, the protective film 6 composed of a nickel plating film hardly dissolves.
There is a tendency that the phosphate film 8 cannot be formed on the surface of the protective film 6. On the other hand, if the nitrate ion concentration is too high, not only the further effect of forming a film cannot be expected, but also the passivation of nickel is promoted and the formation of the phosphate film 8 tends to be inhibited.

It is possible to treat other phosphating solutions, that is, manganese phosphate, iron phosphate, calcium zinc phosphate, etc., in the same manner as zinc phosphate.

In the case of treating aluminum with zinc phosphate, peroxides and fluorides are used as film-forming accelerators. However, the surface of the Ni may be excessively roughened to lower the adhesive strength. Therefore, it is preferable to use nitrate ions in which the reaction proceeds relatively slowly.

The pH of the treatment liquid is preferably 4 or less. If the pH of the processing solution is too high, zinc phosphate cannot be dissolved in the processing solution, the form of the phosphate changes, sludges and precipitates in the solution, and thus the surface of the protective film 6 made of a nickel plating film. This is because there is a tendency that no phosphate film is formed. If the pH of the treatment liquid is too low, the formation of the phosphate coating 8 is hindered, and the protection film 6 made of a nickel plating film may be damaged, thereby impairing the moisture resistance. Therefore, the lower limit thereof is preferably 2.

The treatment temperature in the above range of bath composition is not particularly limited, since there is no problem in the adhesiveness obtained even under the conditions used for ordinary steel. However, if the processing temperature is too low, the reaction in the processing solution tends to be poor and the processability tends to decrease. On the other hand, if the processing temperature is too high, spots and the like may occur and the appearance may be impaired, so the processing temperature is preferably 20 to 50 ° C, more preferably 30 to
５０50 ° C.

The treatment time in the bath composition in the above range is preferably 3 to 30 minutes, more preferably 5 to 15 minutes. If the treatment time is too short, the treatment liquid does not sufficiently contact the surface of the protective film 6, and the reaction becomes insufficient, and there is a tendency that a uniform phosphate film 8 cannot be formed. On the other hand, if the treatment time is too long, the thickness T2 of the phosphate coating 8 becomes 0.1 μm or more, and the adhesive strength tends to decrease. That is, by setting the treatment time to a specific range, the phosphate film 8 having a thickness of less than 0.1 μm can be stably formed at the production level.

(6) Next, the substrate is washed with pure water and dried. At this time, drying is usually performed at 80 to 150 ° C. to remove moisture on the surface, but it is also preferable to immerse in alcohol and air-dry to simplify the process. Since the phosphate film 8 formed on the surface of the protective film 6 is a film at a level that cannot be observed with a microscope, if a certain amount of water is removed, the water evaporates during drying such as a thick film (including crystal water). ) Hardly causes cracks or the like.

(7) Through the above steps, FIG.
The permanent magnet 2 according to the embodiment shown in FIG.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can be implemented in various modes without departing from the gist of the present invention. Of course.

[0074]

EXAMPLES Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.

Example 1 14.7Nd-79.2 prepared by powder metallurgy
An ingot having a composition of Fe-6.1B (the number is an atomic ratio) was roughly pulverized, and further subjected to jet mill pulverization with an inert gas to obtain a fine powder having an average particle size of about 3.5 μm. The obtained fine powder was subjected to magnetic field molding, sintering, and heat treatment to obtain a sintered body. The obtained sintered body is 10 mm × 20 mm × 5 m thick
m, and chamfered by barrel polishing to obtain a permanent magnet main body.

Next, a sample of this permanent magnet body was
After washing with alkaline degreasing solution, through the etching process,
An electric nickel plating was performed to form a protective film made of an electric nickel plated film on the surface of the permanent magnet main body. The thickness of the protective film made of the electro-nickel plating film was 15 μm.

Next, the permanent magnet body on which the protective film was formed was degreased with an alkaline solution (manufactured by Meltex Co., Ltd., Endox Q-576S) and then washed with pure water.

Next, a phosphate (zinc phosphate) treatment was performed using a fluoride-free treatment solution having the following composition. Zinc ion: 1.0 g / l, phosphate ion: 15.0 g / l, nitrate ion: 3.2 g / l, treatment temperature: 50 ° C., immersion time: 5 minutes.

After immersion, washing with pure water is performed,
Drying was performed under the conditions of minutes to obtain a permanent magnet sample. The thickness of the zinc phosphate coating was adjusted by SEM (Scanning Electron Micr).
(microscope), it was less than 0.1 μm.

Example 2 A permanent magnet sample was obtained in the same manner as in Example 1 except that the immersion time in the treatment solution in the phosphate treatment was changed to 30 minutes. When the thickness of the zinc phosphate coating was observed by SEM, it was less than 0.1 μm as in Example 1.

Example 3 Phosphate (manganese phosphate) was prepared by using the following treatment solutions.
A permanent magnet sample was obtained in the same manner as in Example 1 except that the treatment was performed. Determine the thickness of the manganese phosphate coating by SEM
As a result, it was less than 0.1 μm as in Example 1.

Manganese ion: 1.2 g / l, iron ion: 0.3 g / l, phosphate ion: 16.0 g / l, nitrate ion: 4.0 g / l.

Example 4 A permanent magnet sample was obtained in the same manner as in Example 1 except that a phosphate (zinc calcium phosphate) treatment was performed using the treatment solution shown below. When the film thickness of the zinc calcium phosphate film was observed with a SEM, it was found that the film thickness was 0.1 mm as in Example 1.
It was less than 1 μm.

Zinc ion: 1.0 g / l, calcium ion: 0.3 g / l, phosphate ion: 14.0 g / l, nitrate ion: 3.0 g / l.

Comparative Example 1 A permanent magnet sample was obtained in the same manner as in Example 1 except that the zinc phosphate treatment was not performed.

Comparative Example 2 Example 1 was repeated except that a zinc phosphate treatment was carried out using a treatment solution composed of an acid containing fluoride (Metex Acid Salt M-629, 120 g / l, manufactured by Nippon Magdermid Co., Ltd.). In the same manner as in the above, a permanent magnet sample was obtained. The thickness of the zinc phosphate film was 3 μm when calculated by observing a cross section using an electron microscope.

Comparative Example 3 A permanent magnet sample was obtained in the same manner as in Example 1 except that zinc phosphate treatment was performed using the treatment liquids described below.
When the film thickness of the zinc phosphate film was calculated in the same manner as in Comparative Example 2, it was 8 μm.

Zinc ion: 1.0 g / l, phosphate ion: 15.0 g / l, nitrate ion: 3.2 g / l, hydrosilicofluoric acid: 2.0 g / l.

Comparative Example 4 A permanent magnet sample was obtained in the same manner as in Example 1 except that zinc phosphate treatment was performed using the treatment liquid shown below.
When the thickness of the zinc phosphate coating was calculated in the same manner as in Comparative Example 2, it was 12 μm.

Zinc ion: 1.0 g / l, phosphate ion: 15.0 g / l, nitrate ion: 3.2 g / l, hydrosilicofluoric acid: 5.0 g / l.

Comparative Example 5 A protective film formed of a nickel plating film was alkali-degreased, and then immersed in a 20 g / l chromic anhydride solution at 40 ° C. for 10 minutes to form a chromate film on the surface of the protective film. In the same manner as in Example 1, a permanent magnet sample was obtained. When the thickness of the chromate film was calculated in the same manner as in Comparative Example 2, it was 0.8 μm.

Evaluation method The following test was conducted to compare the zinc phosphate coating with the adhesive strength. About 0.008 to 0.010 g of an anaerobic acrylic adhesive (Loctite 638UV) is applied to the surface of the zinc phosphate coating of each permanent magnet sample obtained in Examples 1 to 4 and Comparative Examples 1 to 5. And
After compression bonding to the iron plate whose surface was washed, it was put into a dryer heated to 100 ° C. for 30 minutes, and then subjected to a compression shear test. The number of samples was 10 each, and the average value was taken as the adhesive strength. The compression-shear test was performed at room temperature at a speed of 5 mm / min. Table 1 shows the results.

In order to compare the curing time with the adhesive strength, the following test was conducted. About 0.002 to 0.003 g of an anaerobic acrylic adhesive (Loctite 638UV) was applied to the surface of the zinc phosphate coating of each permanent magnet sample obtained in Example 1 and Comparative Examples 1 and 5, After crimping on a steel plate whose surface has been cleaned,
3 minutes, 5 minutes, 10 minutes, 15 minutes
A compression shear test was carried out within 1 minute after charging. In this test, the sample shape was 10 mm ×
The strength was measured by a hand press with a 5 mm × 5 mm thickness. The results are shown in Table 2 and FIG.

[0094]

[Table 1]

[0095]

[Table 2]

Consideration As shown in Table 1, the thickness of the zinc phosphate coating was 0.1 μm
In the magnet samples of Examples 1 to 4 which are less than
As compared with the magnet samples of Nos. 5 to 5, the adhesive strength was remarkably excellent, and it was also confirmed that the variation was small.

As shown in Table 2 and FIG. 2, it was confirmed that the magnet sample of Example 1 can achieve a predetermined adhesive strength in a very short time as compared with the magnet samples of Comparative Examples 1 and 5. .

[0098]

As described above, according to the present invention, poor curing of an adhesive which is inactive to a nickel plating film can be effectively eliminated, the dispersion of the adhesive strength is small, and the large adhesive strength is achieved. Can be obtained, and as a result, it is possible to provide a magnet capable of realizing an efficient bonding operation. Further, according to the present invention, it is possible to provide a method for manufacturing a magnet capable of efficiently manufacturing such a magnet.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a permanent magnet according to one embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the curing time and the adhesive strength for each of the permanent magnet samples of Example 1, Comparative Example 1, and Comparative Example 5.

[Explanation of symbols]

 2 ... permanent magnet 4 ... magnet body 6 ... protective film made of nickel plating film 8 ... phosphate film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 22/22 C23C 28/00 C 5E062 28/00 C25D 7/00 K C25D 7/00 H01F 41/02 G H01F 41/02 C22C 38/00 303D // C22C 38/00 303 H01F 1/04 HF term (reference) 4K018 AA27 FA24 KA45 KA58 4K024 AA03 AA09 AB02 BA02 BB14 BC07 CB12 DA04 DA07 GA04 4K026 AA02 AA12 BA03 BB10 CA13 DA16 EA08 EB05 4K044 AA02 AB08 BA06 BA17 BB03 BC02 BC05 CA04 CA16 CA18 5E040 AA04 BC01 BC08 BD01 CA01 HB00 HB14 NN05 NN17 5E062 CC03 CD04 CE04 CF01 CG07

Claims (10)

[Claims] 1. A magnet body containing a rare earth element, a protection film formed of a nickel plating film formed on a surface of the magnet body, and phosphoric acid having a thickness of less than 0.1 μm formed on a surface of the protection film. A magnet having a salt coating. 2. The magnet according to claim 1, wherein the phosphate film is formed by a phosphate treatment using a treatment solution containing no fluoride. 3. The magnet according to claim 1, further comprising an underlayer mainly composed of copper, formed between the magnet main body and the protective film. 4. The magnet body is composed of R (where R is one or more rare earth elements including Y), TM (where TM is F
R-TM- containing a transition element whose main component is e) and B
The magnet according to any one of claims 1 to 3, which is a B-based rare earth magnet. 5. A step of performing electroplating on a surface of a magnet main body containing a rare earth element to form a protective film made of a nickel plating film, and using a processing solution containing no fluoride on the surface of the protective film. Performing a phosphate treatment to form a phosphate coating. 6. The magnet according to claim 5, wherein the phosphate treatment is any one of tin phosphate treatment, iron phosphate treatment, manganese phosphate treatment, zinc phosphate treatment, and zinc calcium phosphate treatment. Manufacturing method. 7. The method according to claim 5, wherein the pH of the treatment liquid is 4 or less, and the treatment temperature of the phosphate treatment is 20 to 50 ° C. 8. The treatment liquid contains 2 to 30 nitrate ions.
6. The composition according to claim 5, wherein the content is g / l.
3. The method for producing a magnet according to item 1. 9. Prior to forming the protective film, the surface of the magnet main body is subjected to a degreasing treatment using an alkali solution, and is subjected to chemical etching with an acid to clean the surface of the magnet main body. The method for manufacturing a magnet according to claim 5, further comprising a processing step. 10. The magnet according to claim 5, further comprising a second pretreatment step of performing a degreasing treatment using an alkali solution on the surface of the protective film before forming the phosphate film and cleaning the surface. Production method.