JPH11260614A - Anticorrosive r-fe-b bonded magnet and manufacture of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an anticorrsive R-Fe-B bonded magnet, including an optimum industrial process, for providing an anticorrosive coating with high contact strength and good dimensional accuracy on the surface of a porous R-Fe-B bonded magnet, where a plating solution and a cleaning solution are prevented from entering and remaining. SOLUTION: A R-Fe-B bonded magnet is subjected to barrel abrasion by a barrel device using a dry method using Al fine pieces such as spherical, block- like, or needle-like (wire) shapes having predetermined dimensions as a medium, and the crushed Al fine pieces are applied under pressures to a resin surface and a sealing hole part on the surface of the bonded magnet. The Al fine pieces are also applied to the magnetic powder surface, and zinc substitution processing is carried out for preventing the dissolution of Al at the subsequent electroplating. Thus, high conductivity can be imparted by forming an Al coating film on the surface of the R-Fe-B bonded magnet, so that a fine electrolytic plating layer having no pin hole can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ring-shaped or disk-shaped bonded R-Fe-B magnet having improved corrosion resistance with a metal film having high cleanliness.
By dry barrel polishing of fine particles with metal media, the crushed Al fine particles are pressed and coated on the resin surface and holes of the bonded magnet surface, and the magnetic particles are coated with Al fine particles, and then further substituted with zinc. The treatment gives sufficient conductivity to the magnet surface, enables direct electroplating without electroless plating, and provides a high corrosion resistant R-Fe-B bonded magnet with excellent plating adhesion. The production method to be obtained.

[0002]

2. Description of the Related Art Today, bonded magnets called rubber magnets or plastic magnets having various shapes such as a ring shape and a disk shape include conventional isotropic bonded magnets, anisotropic bonded magnets, and ferrite-based bonded magnets. Higher performance has progressed from bonded magnets to rare earth-based bonded magnets with higher magnetic force.
In the case of sintered magnets, R-Fe-B based magnetic materials that exhibit high magnetic properties with a maximum energy product of 50 MGOe or more are used.
Higher performance has been achieved for Fe-B based bonded magnets.

[0003] R-Fe-B bonded magnets have a problem that they are easily rusted due to the fact that the magnetic powder composition contains a very easily oxidizable component phase and a large amount of Fe. It was applied by a spray method, an immersion method, an impregnation method or the like (for example, JP-A-1-166519, JP-A-1-245504).

[0004] In the case of a resin coating method which has been used to improve the corrosion resistance of R-Fe-B bonded magnets, for example, in the case of a ring method, a paint loss is large in the case of a ring-shaped bonded magnet. Many man-hours,
There is also a problem that the uniformity of the film thickness is poor.

Further, in the electrodeposition coating method, although the film thickness is uniform, it is necessary to attach each of the magnets to an electrode, and it is necessary to repair the trace of the electrode portion removed after coating, that is, to perform touch-up. However, there is a problem that it requires a large number of man-hours and is particularly unsuitable for small items.

[0006] In the immersion method, it is difficult to obtain a coating film having a uniform thickness by a problem such as sagging. In a porous bonded magnet, the pores are not sufficiently filled, and the pores may swell when dried, or the product may be swelled. There is a problem such as adhesion between them.

Regarding the method of forming the metal film, in consideration of mass productivity, electrometal plating performed with a sintered R-Fe-B magnet is applied (Japanese Patent Application Laid-Open Nos. 60-54406 and 62-120003). No.) is considered, but R-Fe-
Since the surface of the B-based bonded magnet has a porous and low-conductivity resin portion exposed, a plating solution remains or a pinhole (unplated portion) occurs due to insufficient formation of a plating film on the resin portion. , Rust occurs.

Therefore, a method of selecting a plating solution which is harmless even if it enters and remains in a porous bonded magnet (Japanese Patent Laid-Open No. 4-2)
No. 76092) or a method of plating after applying a resin coating to the base (Japanese Patent Application Laid-Open Nos.
No. 276095).

However, it is difficult to adjust the pH of the plating solution or completely render it harmless, and no plating bath with good film forming efficiency has been found, and the variation in the thickness of the underlayer becomes an unstable factor of the plating layer. If a sufficient thickness of the undercoating is applied, there is a contradiction that the plating layer on the surface becomes unnecessary.

A plating bath having a specific composition has been proposed (Japanese Patent Laid-Open No. 4-99192) as a method for applying Ni plating with high film-forming efficiency to an R-Fe-B-based bonded magnet.
Also, there is a possibility that it may enter the bonded magnet, remain, and rust.

On the other hand, in structural materials and the like, Cu strike plating usually performed before Ni plating is either strongly alkaline or strongly acidic, and is unsuitable as a treatment for R—Fe—B based bonded magnets. .

A high-temperature acid bath type NiP plating process has been put to practical use to impart abrasion resistance to electronic parts or as a rust preventive treatment for steel plates for automobiles.
When applied to an R—Fe—B bonded magnet, it is unsuitable because it corrodes the inside of the magnet.

[0013]

Therefore, it is possible to prevent a plating solution, a cleaning solution, and the like from penetrating and remaining in the porous R-Fe-B-based bonded magnet, and to efficiently form a plating layer such as electric Ni plating. A method for manufacturing an R—Fe—B-based bonded magnet having a configuration capable of improving corrosion resistance is as follows: (1) A mixture of resin and conductive powder is coated on the surface of the R—Fe—B-based bonded magnet, and the surface of the material is coated. A method for forming a conductive coating layer. (2) A method in which an adhesive resin layer is formed on the surface of an R—Fe—B-based bonded magnet, and a metal powder is adhered to form a conductive coating layer on the surface of the material (JP-A-5-302176).
issue). (3) A method of applying a mixture of a resin and a conductive powder on the surface of an R—Fe—B-based bonded magnet to form a conductive coating layer, and then performing a surface smoothing treatment (Japanese Patent Application Laid-Open No. 9-186016).
issue). Has been proposed.

However, in the above three methods, various resins are used to seal the pores of the material, and the application (impregnation) and curing (smoothing treatment) of the resin are inevitably complicated. Not preferred.

Further, in the method of applying (impregnating) the resin of the material, it is difficult to uniformly apply the resin to the surface of the material, and even if barrel polishing is performed in a later step, a plated product having excellent dimensional accuracy is obtained. It is difficult to get. Further, the conductive coating layer is a resin layer containing a conductive substance or metal powder, and the resin exposed portion of the bonded magnet is improved on the surface as compared with the R-Fe-B based bonded magnet material. However, due to the manufacturing method, there are not a few coating resin exposed parts,
Since there is a portion with low conductivity on the surface, it is difficult to obtain a uniform and good conductivity surface, and there is a problem that pinholes are easily generated during electroplating.

More recently, R-Fe-B-based bonded magnets used in HDD units of computers have been required to have extremely high surface cleaning properties. Is required.

The present invention solves various problems in the method of electroplating R-Fe-B-based bonded magnets, and improves the corrosion resistance of a ring-shaped or disk-shaped metal magnet with high cleanliness by using a highly clean metal coating. In order to efficiently manufacture R-Fe-B based bonded magnets with a shape, a conductive film is formed on the surface of the bonded magnet with good adhesion, uniformity and high efficiency, and high corrosion resistance R- which can be easily electroplated. An object is to provide an Fe-B based bonded magnet and a method for manufacturing the same.

[0018]

Means for Solving the Problems In the electroplating technique of R-Fe-B based bonded magnets for improving corrosion resistance and surface cleanliness, the present inventors provide a material surface with a very uniform conductivity. The results of various investigations on the method of forming the conductive film are described as follows. As a result, an R-Fe-B-based bonded magnet is formed into a spherical, massive or needle-shaped (wire) amorphous Al having a required size. Using the fine particles as a medium, barrel grinding is performed by a dry method in a barrel device, so that the crushed Al fine particles are pressed into the resin surface and the holes of the bonded magnet surface, covered, and the magnetic powder surface. Al particles are coated on the surface of the R-Fe-B bonded magnet surface by applying a zinc substitution treatment to prevent the elution of Al during the subsequent electroplating. Enables air plating, excellent corrosion resistance, it had less plating film magnetic properties deteriorate R
-It has been found that an Fe-B based bonded magnet can be obtained, and the present invention has been completed.

That is, according to the present invention, Al fine particles are press-fitted and coated on the resin surface and the pores constituting the surface of the R—Fe—B-based bonded magnet, and Al particles are adhered on the surface of the magnetic powder constituting the surface.
A high corrosion resistance R- characterized by having an Al coating layer on the surface of the magnet formed by coating fine particles and an electrolytic plating layer formed on the Al coating surface via a Zn coating layer.
It is an Fe-B based bonded magnet.

Further, the present invention provides a high corrosion resistance R having the above structure.
-In the Fe-B-based bonded magnet, the thickness of the Al coating layer coated on the magnetic powder surface is 1 μm or less, and the thickness of the Al press-fit coating layer formed on the resin surface and the pores is 0.1 μm.
A high corrosion resistant R-Fe-B-based bonded magnet characterized by being not less than 2 µm and not more than 2 µm, and having a Zn layer formed on the surface of the Al coating layer having a thickness of not more than 0.1 µm.

Further, according to the present invention, an R-F
The EB-based bonded magnet and the amorphous Al microparticles were charged and subjected to barrel polishing by a dry method, and ground into a resin surface and a hole constituting the surface of the R-Fe-B-based bonded magnet. After press-fitting and covering Al fine particles, and coating Al fine particles on the surface of the magnetic powder constituting the surface, and forming an Al coating layer on the magnet surface,
This is a method for producing a highly corrosion-resistant R-Fe-B-based bonded magnet, characterized in that an electrolytic plating layer is formed via a Zn coating layer formed by subjecting the conductive Al coating layer to a zinc substitution treatment.

Further, according to the present invention, the high corrosion resistance R
In the method for producing a Fe-B based bonded magnet, the amorphous A
lSpherical, lump or needle-like particles having a size of 0.1 mm to 10 mm, Al particles fined by barrel polishing having a major axis of 5 μm or less, rotation, vibration or centrifugal barrel And performing barrel polishing at a volume ratio (magnet / Al) of the magnet and the Al fine particles of 3 or less, respectively, using R.Fe.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, R-Fe-B
The system-bonded magnet is intended for both isotropic and anisotropic bonded magnets. For example, in the case of compression molding, after adding and kneading a thermosetting resin, a coupling agent, and a lubricant of the required composition and properties of magnetic powder. In the case of injection molding, extrusion molding, and rolling molding, thermoplastic resin, a coupling agent, and a lubricant are added and kneaded, and then injection molding and extrusion are performed. It is obtained by molding by any method of molding and rolling molding.

The R-Fe-B-based magnetic material powder contains a required R-
A melting and pulverizing method in which an Fe-B alloy is melted and pulverized after casting,
Direct reduction diffusion method to obtain powder directly by Ca reduction, required R
A quenching alloy method in which a ribbon foil is obtained by melting a Fe-B-based alloy with a jet caster, and this is pulverized and annealed.
A gas atomizing method in which an EB-based alloy is melted and powdered by gas atomization and heat treatment is performed. Isotropic and anisotropic powders obtained by various methods such as a method of decomposing and recrystallizing a -B-based alloy by heating in hydrogen (HDDR method) can be used.

In the present invention, the rare earth element R used in the R—Fe—B based magnet powder occupies 10 to 30 atomic% of the composition, and at least one of Nd, Pr, Dy, Ho, and Tb is used. Alternatively, La, Ce, Sm,
A material containing at least one of Gd, Er, Eu, Tm, Yb, Lu, and Y is preferable. Also, one of the normal Rs
Although seeds are sufficient, in practice, a mixture of two or more kinds (mish metal, sijim, etc.) can be used for reasons such as convenience in obtaining. Note that R may not be a pure rare earth element, and may contain impurities that are unavoidable in production within the industrially available range.

R is an essential element in the above system magnet powder, and if it is less than 10 atomic%, the crystal structure becomes a cubic structure having the same structure as α-iron, so that high magnetic properties, particularly high coercive force, cannot be obtained. , More than 30 atomic%, the R-rich nonmagnetic phase increases, the residual magnetic flux density (Br) decreases, and a permanent magnet having excellent characteristics cannot be obtained. Therefore, R is desirably in the range of 10 at% to 30 at%.

B is an essential element in the above-mentioned system magnet powder. If it is less than 2 atomic%, the rhombohedral structure becomes the main phase, and a high coercive force (iHc) cannot be obtained. Increase in non-magnetic phase, residual magnetic flux density (Br)
, The excellent permanent magnet cannot be obtained. Therefore, B is desirably in the range of 2 to 28 atomic%.

Fe is an essential element in the above-mentioned system magnet powder. When the content is less than 65 atomic%, the residual magnetic flux density (Br) decreases. When the content exceeds 80 atomic%, a high coercive force cannot be obtained. % To 80 atomic%.

Further, by substituting a part of Fe with Co, the temperature characteristics can be improved without impairing the magnetic characteristics of the obtained magnet.
%, It is not preferable because the magnetic properties are deteriorated. The substitution amount of Co is 5 atomic% or more in total amount of Fe and Co.
In the case of 15 atomic%, since (Br) increases as compared with the case where no substitution is made, it is preferable to obtain a high magnetic flux density.

In addition to R, B, and Fe, the presence of impurities that are inevitable in industrial production can be tolerated. For example, a part of B may be 4.0 wt% or less of C, 2.0 wt% or less of P, .0
By replacing at least one of S by wt% or less and Cu by 2.0 wt% or less with a total amount of 2.0 wt% or less, it is possible to improve the productivity and reduce the cost of the permanent magnet.

Further, Al, Ti, V, Cr, Mn, B
i, Nb, Ta, Mo, W, Sb, Ge, Ga, Sn,
At least one of Zr, Ni, Si, Zn, and Hf is added to the magnet powder because it is effective for improving the coercive force and the squareness of the demagnetization curve or improving the productivity and reducing the price. be able to. The upper limit of the addition amount is desirably a range that satisfies the conditions necessary for setting the (BH) max and (Br) values of the bonded magnet to required values.

In the present invention, 6 Pa, 12 Pa, PPS, P
BT, EVA, etc., PVC, NBR, CPE, NR, Hypalon, etc. for extrusion molding, calender roll, roll molding, and epoxy resin, DAP, phenolic resin, etc. for compression molding. Metal binder can be used. Further, a lubricant that facilitates molding, a binder between a resin and an inorganic filler, a silane-based or titanium-based coupling agent, or the like can be used as the auxiliary material.

In the present invention, a known barrel such as a rotary type, a vibration type, and a centrifugal type can be used as the dry barrel. A
Regarding the shape of 1 minute piece, amorphous Al such as a sphere, a lump or a needle (wire) can be used. If the size of the Al fines is less than 0.1 mm, sufficient press-fitting and coating takes a long time, which is not practical, and if it exceeds 10 mm, the surface unevenness increases, and the entire surface can be coated with Al. Therefore, the size of Al is desirably 0.1 mm to 10 mm, and a more preferred range is 0.5 mm to 5 mm.

In the present invention, the Al fines charged in the dry barrel may have the same shape and size, or may mix different shapes and sizes. Also, Al fine powder may be mixed into irregular Al fine pieces.

Further, the ratio of the amount charged in the dry barrel polishing and the volume ratio of the magnet and the Al fine particles (magnet / Al) are limited to 3 or less. If the ratio exceeds 3, it takes time for press-fitting and coating of the Al fine particles. Therefore, the particle size is not practical, and the magnetic powder is degranulated from the surface of the bonded magnet. Also, the amount of the bonded magnet and Al fines to be charged into the barrel polishing machine is preferably 20% to 90% of the internal volume of the polishing machine. If it is less than 20%, the processing amount is too small to be practical, and if it exceeds 90%, stirring occurs. Is insufficient and sufficient polishing cannot be performed.

The Al fine particles to be pressed into and coated on the resin surface and the pores constituting the surface of the magnet are fine powders or needle-like pieces. Was poor, and poor adhesion and peeling occurred during electrolytic plating. A preferred range is 2 μm or less in major axis.

In the present invention, regarding the press-fitting and coating of Al fine particles, the Al fine particles are press-fitted and coated on the soft resin surface and the void portion of the bonded magnet surface, and are coated on the magnetic powder surface.
The amount press-fitted into the resin surface and the holes is larger at the surface, and the content gradually decreases inside the resin layer. The reason why the thickness of the Al press-fit layer on the resin surface and the void portion is limited to 0.1 μm or more and 2 μm or less is that sufficient conductivity cannot be obtained if the thickness is less than 0.1 μm, and if it exceeds 2 μm, there is a problem in performance. Not practical, but time consuming and impractical. The reason why the thickness of the Al coating layer on the magnetic powder surface of the bonded magnet surface is limited to 1 μm or less is that the reaction between the magnetic powder surface and the Al particles is a kind of mechanochemical reaction. Is inferior.

In the present invention, when the surface of the bonded magnet is required to be smooth, before performing the treatment of the present invention,
Improves smoothness by performing a process such as barrel polishing by a dry method using a mixture of an abrasive and a vegetable medium, and a mixture of an abrasive and a vegetable medium whose surface has been modified with inorganic powder as a medium. R-Fe with even better corrosion resistance
-A B-based bonded magnet can be obtained.

The number of revolutions in the case of the dry method barrel polishing according to the present invention is 20 to 50 rpm in the case of a rotating barrel.
m, in the case of a centrifugal barrel, the number of rotations is 70 to 200 rpm, and in the case of the vibration barrel polishing method, the vibration amplitude is 0.5 to 50 mm.
Is preferred.

In the present invention, the zinc replacement is for preventing the elution of Al during the subsequent electroplating, and the zinc replacement method is preferably a washing → zinc replacement → washing process.
When there is a deposit such as dirt on the Al surface, it is preferable to perform cleaning by immersion and degreasing with a solution of sodium carbonate and sodium triphosphate.

The zinc substitution treatment itself is preferably carried out by immersion in a solution containing zinc oxide, sodium hydroxide, ferric chloride, Rossell salt, etc., for example, at 10 ° C. to 25 ° C. for 10 seconds to 2 minutes. preferable. The Zn layer to be formed has a very surface layer of Zn.
The thickness of the Zn layer formed and formed in the form of O _x (X = 0 to 1) is 0.1 μm or less. However, if the layer thickness exceeds 0.1 μm, poor adhesion occurs, which is not preferable.

In the present invention, the electroplating method includes:
Ni, Cu, Sn, Co, Zn, Cr, Ag, Au, P
A plating method in which B, S, and P are contained in at least one metal selected from b, Pt, or the like or an alloy thereof is preferable, and Ni plating is particularly preferable. The plating thickness is 50 μm or less, preferably 10 to 30 μm. In the present invention, general plating is possible because the press-fitting and coating of the metal fine particles described above are effective, and excellent adhesion and corrosion resistance are obtained.

The plating method of the Ni plating bath is preferably performed in the steps of washing → electroplating → washing → drying, and drying is preferably performed at 70 ° C. or more.

Various bathtubs can be used for the plating bath depending on the shape of the bond magnet. In the case of a ring-shaped bond magnet, trapping plating and barrel plating are preferred.

Various bathtubs can be used for the plating bath depending on the shape of the bond magnet. In the case of a ring-shaped bond magnet, trapping plating and barrel plating are preferable.

[0046]

EXAMPLES Example 1 Nd 12 at%, Fe 77 at%, produced by a rapid quenching method
B6 at%, Co 5 at% composition, average particle size 15
After adding 2 wt% of epoxy resin to the 0 μm alloy powder and kneading, compression-molding at a pressure of 7 ton / cm ² , 170
Cure at 2 ℃ for 2 hours, outer diameter 20mm × inner diameter 17mm ×
A ring-shaped bonded magnet having a height of 6 mm was produced. The characteristics of the obtained bonded magnet were Br 6.9 kG, iHc 9.4 k
Oe, (BH) max 9.6 MGOe.

The obtained bonded magnet is put in a vibration barrel,
Dry barrel polishing was performed using a short columnar Al piece having a diameter of 0.8 mm and a length of 1 mm to form a conductive coating layer of the Al piece. The press-fitting coating depth of the Al particles on the resin surface was about 0.9 μm, and the coating thickness on the magnetic powder surface was 0.5 μm.

The processing conditions for barrel polishing are as follows:
Into 1 vibrating barrel, 200 bonded magnets (apparent volume 0.7 l, weight 450 g) and Al fine particles of the above dimensions (apparent volume 20 l, weight 100 kg) were charged and treated for 5 hours.

After washing and zinc substitution, Ni plating was carried out by a hook plating method. The film thickness after plating was 19 μm on the inner diameter side and 21 μm on the outer diameter side.
The obtained ring-shaped bonded magnet was heated to 80 ° C. and 90% relative humidity.
%, An environmental test (moisture resistance test) was performed at 500 hours. The results and the film thickness dimensional accuracy are shown in Tables 1 to 3.

The conditions of the zinc substitution treatment were as follows: treatment time: 1 minute, bath temperature: 20 ° C., liquid composition: sodium hydroxide 280 g / l, zinc oxide 50 g / l, ferric chloride 1 g / l
1 and 25 g / l of Rossell salt. Thickness is 0.02μ
m.

The conditions for the electric Ni plating were as follows: current density 2 A / dm ² , plating time 60 minutes, pH 4.1, bath temperature 5
5 ° C. and the plating solution composition was nickel sulfate 250 g /
l, nickel chloride 55g / l, appropriate amount of nickel carbonate (pH
Adjustment), boric acid 36 g / l.

Comparative Example 1 A ring-shaped bonded magnet obtained in the same manner as in Example 1 was washed, and then subjected to electroless copper plating. The plating thickness was 7 μm. After the electroless copper plating, Ni plating was performed under the same conditions as in Example 1. The obtained ring-shaped bonded magnet was heated at 80 ° C.
Environmental test at 90% relative humidity for 500 hours (moisture resistance test)
Was done. The results are shown in Tables 1 to 3.

The conditions for the electroless copper plating were a plating time of 30 minutes, a pH of 11.7 and a bath temperature of 22 ° C. The plating solution composition was copper sulfate 31 g / l, sodium carbonate 27 g / l,
Tartrate 160 g / l, sodium hydroxide 40 g / l,
140 ml of 37% formaldehyde.

Comparative Example 2 After washing the ring-shaped bonded magnet obtained in the same manner as in Example 1, a phenol resin and Ni powder were mixed to form an 8 μm conductive film. After the treatment, Ni plating was performed under the same conditions as in Example 1. The obtained ring-shaped bonded magnet was heated at 80 ° C.
Environmental test at 90% relative humidity for 500 hours (moisture resistance test)
Was done. The results are shown in Tables 1 to 3.

The conductive film processing conditions were as follows:
The composition of the treatment liquid was 5 wt% of phenol resin, 4 wt% of Ni powder (particle diameter 0.7 μm or less), and 91 wt% of MEK (methyl ethyl ketone).

Comparative Example 3 After washing the ring-shaped bonded magnet obtained in the same manner as in Example 1, a phenol resin layer serving as an adhesive layer was previously formed by an immersion method, and then Ag powder (particle diameter 0.7 μm or less) was added. After adhering to the surface, a conductive coating layer of 10 μm was formed with a vibration barrel. After the vibration barrel treatment, Ni plating was performed under the same conditions as in Example 1. The obtained ring-shaped bonded magnet was heated at 80 ° C.
Environmental test at 90% relative humidity for 500 hours (moisture resistance test)
Was done. The results are shown in Tables 1 to 3.

The vibration barrel processing conditions were a volume of 3.5.
Using 50 vibrating barrels and loading 50 bonded magnets,
The treatment was performed for 4 hours using a 2 mm steel ball having an apparent volume of 2 l as a medium.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3]

As is clear from Tables 1 to 3, Comparative Example 1
In about 120 hours, spot rust was observed after about 120 hours.
After a lapse of time, Comparative Example 3 also showed spot rust after about 300 hours, whereas Example 1 did not show any spot rust even after 500 hours under a microscope of 30 times magnification.

[0062]

According to the present invention, an R-Fe-B based bonded magnet is formed by a dry method in a barrel apparatus using spherical, massive or needle-shaped (wire) or other irregular shaped aluminum fine particles as a medium. Barrel polishing is performed, and the finely ground Al fines are pressed into the holes and the resin surface and coated, and the magnetic fine particles are coated with the Al fines, so that the R-Fe-B-based bonded magnet surface is coated with Al. After forming the covering film, by further performing zinc substitution treatment, it is possible to form the metal covering film on the surface of the R—Fe—B-based bonded magnet and to impart extremely high conductivity,
Therefore, it is possible to form a dense electrolytic plating layer without pinholes, and it is possible to obtain an R—Fe—B-based bonded magnet having extremely excellent corrosion resistance.

In particular, the bonded magnet of the present invention can be used in a computer HD that requires excellent surface cleanliness and dimensional accuracy.
This is effective for D units and the like.

Claims (8)

[Claims] An Al fine particle is press-fitted and coated on a resin surface and a void portion constituting a surface of an R—Fe—B-based bonded magnet,
Further, a high corrosion resistance R having an Al coating layer on the surface of the magnet formed by coating Al particles on the surface of the magnetic powder constituting the surface and an electrolytic plating layer formed on the surface of the Al coating layer via a Zn layer. -Fe-B based bonded magnet. 2. The high corrosion resistance RF according to claim 1, wherein the thickness of the Al coating layer coated on the surface of the magnetic powder is 1 μm or less.
e-B bond magnet. 3. The method according to claim 1, wherein the thickness of the Al coating layer formed on the resin surface and the hole is 0.1 μm or more and 2 μm or more.
The following high corrosion resistance R-Fe-B-based bonded magnets. 4. The method according to claim 1, wherein the Zn layer has a thickness of 0.1 μm.
m or less, a high corrosion-resistant R-Fe-B-based bonded magnet. 5. A resin constituting the surface of an R-Fe-B-based bonded magnet, wherein an R-Fe-B-based bonded magnet and amorphous Al fines are charged into a barrel device and subjected to barrel polishing by a dry method. Press-fit and cover the Al particles crushed into the surface and the holes,
In addition, after coating the Al particles on the surface of the magnetic powder constituting the surface and forming an Al coating layer on the magnet surface, the conductive Al coating layer is subjected to a zinc substitution treatment through a Zn coating layer formed thereon. A method for producing a high corrosion-resistant R-Fe-B-based bonded magnet for forming an electrolytic plating layer. 6. The method according to claim 5, wherein the amorphous Al fine particles are spherical, massive, or acicular having a size of 0.1 mm to 10 mm, and have high corrosion resistance. 7. The method according to claim 5, wherein the Al fine particles ground by barrel polishing have a major axis of 5 μm or less in size. 8. The volume ratio of magnet to Al fines (magnet / magnet / rotation) using a rotation, vibration or centrifugal barrel.
Al) 3 or less, high corrosion resistance RF with barrel polishing
A method for producing an e-B bonded magnet.