JP3236816B2 - High corrosion resistance R-Fe-B bonded magnet and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for improving the corrosion resistance of R--Fe--B bonded magnets, and more particularly to a method for removing abrasive powder, bonded magnet debris, and inorganic powder by dry barrel polishing. After embedding in the pores and sealing and smoothing the surface, using an irregular shaped metal piece having a Vickers hardness value of 80 or less, such as a spherical, massive or needle-like (wire) having a size of 0.1 mm to 10 mm. By barrel-polishing the magnet material by a dry method in a barrel device, pressing and covering the crushed metal fine particles into a resin surface and a sealing portion, and coating the metal fine particles onto the magnetic powder surface R-Fe
-By providing conductivity to the surface of the B-based bonded magnet and providing a highly corrosion-resistant plating layer that can be efficiently formed with good productivity without limiting the plating bath such as post-treatment electric Ni plating,
High corrosion resistance R-Fe-B with significantly improved corrosion resistance and adhesion
The present invention relates to a method for manufacturing a bonded magnet.

[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.

The inventor of the present invention carried out barrel polishing by a dry method using a mixture of a vegetable medium or a vegetable medium whose surface was modified with an inorganic powder and an abrasive, as a medium. Abrasive debris is fixed to the pores of the bonded magnet with the fat and oil of vegetable medium, sealed and smoothed,
A method of forming a conductive layer by electroless copper plating using an alkaline bath was proposed (30P97060).

However, the electroless copper plating has a problem that the life of the plating solution is short and it is difficult to manage the solution to obtain a good plating film. Furthermore, although corrosion resistance and dimensional accuracy are superior to those of the prior art, even higher corrosion resistance is required to meet various applications today.

An object of the present invention is to provide an R—Fe—B-based bonded magnet having extremely high corrosion resistance which does not rust even in a long-time high-temperature and high-humidity test. Corrosion-resistant coating of R-F
An object of the present invention is to provide a manufacturing method that can be formed into an eB-based bonded magnet.

Further, according to the present invention, in a conventional electroless plating method, a plating solution, a cleaning solution and the like are made of porous R-Fe.
A method of manufacturing a high corrosion resistant R-Fe-B based bonded magnet comprising an industrial process which is optimal for providing a corrosion resistant coating with high adhesion strength and high dimensional accuracy on a magnet surface which prevents penetration and remaining of the B based bonded magnet. The purpose is to provide.

[0020]

In order to solve such a problem, the present inventors have developed a porous R-Fe-B-based bonded magnet using
A mixture of an abrasive obtained by baking inorganic powders such as l ₂ O ₃ and SiC and a vegetable medium such as a fruit husk and a corn core, or a surface modified with the above abrasives and the above inorganic powder By applying barrel polishing by a dry method using a mixture of a vegetable medium as a medium, ground powder such as abrasive powder and inorganic powder for reforming and surface oxide layer of magnetic powder constituting a bonded magnet were ground. Polishing waste can be fixed and sealed in the pores of the magnet by the oils and fats of the vegetable medium, and the surface can be smoothed at the same time. It has been found that a conductive film can be formed directly on the surface.

Furthermore, the present inventors have conducted various studies on the method of forming the conductive film. As a result, the R-Fe-B-based bonded magnet was determined to have a Vickers hardness value such as spherical, massive or needle-like (wire) having a required size. R but using the 80 following amorphous metal strip as a medium, subjecting the bar <br/> barrel polishing method by dry method at a barrel apparatus, i.e., a dry barrel device
-Fe-B bonded magnet and irregular shaped metal pieces are inserted and rotated
By applying a dry barrel treatment for imparting vibration and the like , the crushed metal fine particles are pressed into the resin surface and the sealing portion of the bonded magnet surface and coated, and the metal fine particles are similarly coated on the magnetic powder surface. R-Fe-B-based bonded magnet plating that can provide a very uniform conductive film on the surface of the R-Fe-B-based bonded magnet, enables good electroplating, has excellent corrosion resistance, and has little deterioration in magnetic properties. The inventors have found that a coated product can be obtained, and have completed the present invention.

[0022] Namely, the present invention is the least is ground to a vacancy portion formed on R-Fe-B based bonded magnet table surface
Sticking even powder abrasives in oils and fats of vegetable medium, the sealing has been R-Fe-B permanent magnet surface, the Vickers Hardness of 80 conductive coating layer of less milled fine pieces of metal and,
A highly corrosion-resistant R-Fe having an electrolytic plating layer formed through a conductive coating layer of the metal particles.
-B-based bonded magnet.

Further, the present inventors have proposed a high corrosion resistance R having the above structure.
-In the Fe-B-based bonded magnet, the metal conductive coating layer;
Of the thickness of the portion formed on the resin surface configuring the surface of the magnet and the cavity is 0.1μm or more 2μm or less, formed on the magnetic powder surfaces constituting the said metal conductive coating layer, a magnet surface the thickness of portions is Ru der 1.0 [mu] m or less,
Each propose together high corrosion resistance R-Fe-B based bonded magnet is characterized.

Further, the present invention relates to a dry barrel device having an R-barrel.
And Fe-B based bonded magnet, a mixture of vegetable media with abrasive material
Or vegetable medium modified surface by inorganic powder and Ken
Charge a mixture of abrasives and polish by dry barrel polishing.
The powder of at least the abrasive produced by the crushing is R-Fe-
Fixed at grease vegetable medium cavity formed in the B permanent magnet surface, after sealing, a dry barrel unit R-Fe
-B based bonded magnet and Vickers Hardness is charged 80 following amorphous metal strip, said non amorphous metal by the dry barrel treatment
After Vickers hardness pieces are generated is ground has a conductive coating layer with fine pieces 80 following gold <br/> genus formed on the magnet surface, this
Electroplating through a conductive coating layer of fine metal particles
And a method for manufacturing a highly corrosion-resistant R-Fe-B based bonded magnet and forming an electroless plating layer.

The inventors have also proposed a high corrosion resistance R having the above structure.
In the method for producing a Fe-B-based bonded magnet, the abrasive is an abrasive stone or a metal ball obtained by baking inorganic powder, and the vegetable medium is vegetable peel, sawdust, fruit shell, corn core. That the irregular shaped metal piece is spherical, massive or needle-shaped with a size of 0.1 mm to 10 mm, and that the irregular shaped metal piece is dry barrel treated with a dry barrel device.
That the size of the resulting metal fine pieces shaped metal piece is ground is less diameter 5 [mu] m, rotating, the volume ratio of the vibration or a magnet and the Vickers hardness using a centrifugal barrel 80 following amorphous metal pieces (magnet / Metal) is 3 or less , conductive coating layer
Carrying out the formation, and wherein each high corrosion resistance R-F
A method for manufacturing an e-B bonded magnet is also proposed.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, R-Fe-B
The system bond magnet is intended for both isotropic and anisotropic bond magnets. For example, in the case of compression molding, after adding and kneading the required composition, thermosetting resin of magnetic powder of properties, coupling agent, lubrication, etc. In the case of injection molding, extrusion molding, and rolling molding, a thermoplastic resin, a coupling agent, lubrication, etc. 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 has 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, a required alloy metal is powderized, then a mechanical alloying method in which the powder is finely powdered by mechanical alloying and heat treated, and a required R-Fe 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 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 (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-mentioned system magnet powder, and if it is less than 10 atomic%, the crystal structure has the same cubic structure as that of α-iron, so that high magnetic properties, especially 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, and when it exceeds 80 atomic%, a high coercive force cannot be obtained. % To 80 atomic%.

Further, by replacing 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, as a medium for barrel polishing, ceramics obtained by sintering an inorganic powder such as Al ₂ O ₃ or SiC, or an abrasive such as a metal ball, and vegetable shavings, sawdust, Use of a mixture of vegetable medium such as fruit husks, corn cores, or a mixture of the above-described abrasive medium and the above-mentioned vegetable medium whose surface has been modified with an inorganic powder such as Al ₂ O ₃ or SiC . By performing barrel polishing using this mixture as media,
It becomes possible to perform a smooth sealing treatment of the bonded magnet.

The dry barrel polishing for sealing, smoothing, and forming a metal coating layer having a Vickers hardness value of 80 or less on the surface of the bonded magnet according to the present invention includes a known barrel polishing apparatus.
置等 can be used, the rotation barrel of a typical rotational speed 20～50Rpm, centrifugal barrel rpm 70～200Rpm, etc. vibration barrel less 50mm or more vibration amplitude 0.5mm can be employed.

In the case of the rotating barrel and the vibrating barrel used in the sealing and smoothing treatment of the present invention, the total amount of the bonded magnet, the abrasive and the vegetable medium to be charged into the barrel is 20% to 20% of the inner volume. 90% is preferred. If it is less than 20%, the treatment amount is too small to be practical, and if it exceeds 90%, there is a problem that stirring is insufficient and sufficient polishing cannot be performed.

The abrasive used in the sealing and smoothing treatment of the present invention is not particularly limited, but an abrasive having a particle size of 1 to 7 mm, preferably about 3 to 5 mm, and a major axis of 0.5 to 3 mm, preferably a major axis of 1 to 3 mm are used. Using a vegetable medium of about 2 mm or a mixture of the above-mentioned vegetable medium whose surface has been modified with the above-mentioned abrasive and inorganic powder, the mixture of the magnet and the medium is uniformly stirred, and the relative movement motion Is preferably performed under the conditions where

As the vegetable medium whose surface has been modified with the above-mentioned inorganic powder, the surface of the vegetable medium is kneaded and coated with a fat or oil such as wax, and then the A-particle having a particle size of 0.01 to 3 μm is coated.
Inorganic powders of l ₂ O ₃ , SiC, ZrO, and MgO are uniformly coated on the surface and fixed. A sealing material polish
The crushed powder of the abrasive, the inorganic powder for modifying the surface of the vegetable medium, and the polishing debris of the bonded magnet have a particle size of 0.01 to 3 μm.

The ratio of the vegetable medium to the abrasive in the medium (vegetable medium / abrasive) is 1/5 to 2, preferably a mixture having a ratio of 1. The mixing ratio of the bonded magnet and the medium (bonded magnet / media) is set to 3 or less.

In the present invention, the above-mentioned abrasive effectively grinds and removes the surface oxide layer of the magnet, smoothes the surface,
It has the effect of tapping and solidifying the sealing material such as the abrasive powder and the inorganic powder for modifying the surface of the vegetable medium and the grinding dust of the bonded magnet, and the vegetable medium effectively releases the oils and fats. By doing so, it has the effect of increasing the fixing force of the sealing material.

In the present invention, the porosity of the bonded magnet after the surface smoothing treatment can be reduced to 3% or less, and not only the smooth sealing treatment on the surface of the bonded magnet but also the oxide surface layer of the magnet is removed. Surface of the active R-Fe-B-based magnetic powder can be obtained.

In the present invention, the Vickers hardness value is 8
Known barrels such as a rotary type, a vibration type, and a centrifugal type are used in a dry barrel processing apparatus using a metal piece made of Sn, Zn, Pb, Cd, In, Au, Ag and an alloy thereof of 0 or less. Can be used. Regarding the shape of the metal piece, an amorphous metal such as a sphere, a lump, or a needle (wire) can be used. When the size of the metal piece is less than 0.1 mm, sufficient press-fitting and coating takes a long time, which is not practical, and when it exceeds 10 mm, the surface unevenness becomes large, and the entire surface cannot be coated with metal. Therefore, the size of the metal is desirably 0.1 mm to 10 mm, and a more preferred range is 0.5 mm to 5 mm. Further, in the present invention, the metal pieces to be charged in the dry barrel device may have the same shape and dimensions,
You may mix things of different dimensions. Further, fine metal powder may be mixed into the irregular shaped metal piece.

When the surface of the magnet is coated with a metal having a Vickers hardness value of 80 or less in the dry barrel treatment , the ratio of the magnet and the metal piece (magnet / metal) is limited to 3 or less. The reason for this is that if it exceeds 3, it takes time for press-fitting and coating of the metal, which is not practical, and because the magnetic particles are degranulated from the surface of the bonded magnet, it is set to 3 or less. The amount of the bonded magnet and the metal pieces to be charged in the barrel is preferably 20% to 90% of the barrel internal volume.
If the processing amount is too small to be practical and exceeds 90%,
There is a problem that stirring is insufficient and sufficient polishing cannot be performed.

The metal fine particles to be ground, pressed and coated are fine powders or needle-like pieces. If the size exceeds 5 μm, the adhesion to the magnet surface is not good, and the adhesion is poor during electroplating. In order to cause peeling or the like, the length was set to 5 μm or less. A preferred range is 2 μm or less in major axis.

In the present invention, the press-fitting and coating of the metal particles are performed by press-fitting and coating the soft resin surface and the sealing portion on the resin surface and the sealing portion and the magnetic powder surface on the surface of the bonded magnet. The magnetic powder surface is coated. The amount pressed into the resin surface and the sealing portion is larger at the surface, and the content gradually decreases inside the resin layer. The reason why the thickness of the metal press-fit layer on the resin surface and the sealing 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.
If it exceeds m, there is no performance problem, but it takes time to work,
Not practical. In addition, the reason why the thickness of the metal coating layer on the magnetic powder surface of the bonded magnet surface is limited to 1.0 μm or less is that the reaction between the magnetic powder surface and the metal particles is a kind of mechanochemical reaction. If it exceeds, the adhesion is inferior.

The rotational speed of the case where a barrel Labs <br/> polish device dry type barrel treatment using a metal strip, the rotation speed 20~50rpm For rotating barrel, rotational speed 70 in the case of centrifugal barrel
200rpm, In the case of vibration barrel frequency 60H
z, the vibration amplitude is preferably 3 to 50 mm.

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 Cu and Ni plating are particularly preferable. 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 powder into the resin surface and the sealing portion described above are effective, and excellent adhesion and corrosion resistance are obtained.

The plating method of the Cu and Ni plating baths is preferably performed in the steps of washing → electroplating → washing → drying.
Drying is preferably performed at 70 ° C. or higher.

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.

[0052]

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 for 1 hour at ℃, outer diameter 34mm x inner diameter 31mm
A ring-shaped bonded magnet having a height of 8 mm was produced. The characteristics of the obtained bonded magnet were Br 6.7 kG, iHc 9.1 kO.
e, (BH) max 9.1 MGOe.

100 magnets (200 g) of the obtained magnet were added to 20
After put into vibration barrel l volume with an average diameter of 3 mm Al ₂ O ₃ based spherical barrel stones, having a particle diameter of about 1 [mu] m Al ₂ O ₃
A vegetable medium consisting of walnut nuts with a diameter of about 1 mm, the surface of which has been modified with powder, is charged at 50% of the barrel volume, the surface is polished by a dry method with an amplitude of 20 mm for 120 minutes, and the hole is sealed and smoothed. did.

Next, a bonded magnet is inserted with a vibration barrel,
Using short cylindrical Sn diameter 1mm length 1mm, Zn, and Pb piece performs dry barrel treatment, to form a conductive coating layer of fine metal pieces. Table 1 shows the resin surface of the metal particles, the press-in depth at the sealing portion, and the coating thickness on the magnetic powder surface.

[0055] Incidentally, the dry barrel treatment conditions by vibrating barrel, the vibration barrel volume 3.5 l, 50 Quai of the bonded magnet (apparent volume 0.15 L, weight 100g) and metal pieces of the dimension (apparent volume 2l, Weight 10kg)
The treatment was performed at an amplitude of 20 mm for 2 hours.

Thereafter, washing was carried out, electric Ni plating was carried out by a hook plating method, and then Ni plating was carried out. The film thickness after plating was 21 μm on the inner diameter side and 22 μm on the outer diameter side. The obtained ring-shaped bonded magnet was heated at 80 ° C. and a relative humidity of 9
An environmental test (moisture resistance test) was performed at 0% for 1000 hours. Tables 2 to 4 show the results and the film thickness dimensional accuracy.

The conditions for the electro-Cu plating were as follows: current density 2.5 A / dm ² , plating time 5 minutes, pH 10 and bath temperature 4
At 0 ° C., the composition of the plating solution was copper 20 g / l and free cyanide 10 g / l.

The conditions of the electric Ni plating were as follows: current density 2 A / dm ² , plating time 60 minutes, pH 4.2, bath temperature 5
5 ° C. and the composition of the plating solution was 245 g of nickel sulfate /
l, nickel chloride 45g / l, nickel carbonate appropriate amount (pH
Adjustment), boric acid 32 g / l.

Comparative Example 1 After the ring-shaped bonded magnet obtained in the same manner as in Example 1 was washed, the same sealing and surface smoothing treatment as in Example 1 was performed, followed by washing, followed by electroless copper plating. The plating thickness was 5 μm. After electroless copper plating, Cu under the same conditions as in Example 1
Plating and Ni plating were performed. The obtained ring-shaped bonded magnet was subjected to an environmental test (moisture resistance test) under the same conditions as in Example 1. The results and film thickness dimensional accuracy (moisture resistance test) were performed. The results are shown in Tables 2 to 4.

The conditions of the electroless copper plating were a plating time of 20 minutes, a pH of 11.5, and a bath temperature of 20 ° C. The plating solution composition was copper sulfate 29 g / l, sodium carbonate 25 g / l,
Tartrate 140 g / l, sodium hydroxide 40 g / l,
150 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 and applied under the following conditions to form a 10 μm conductive resin film. The above magnet and a 5 mm steel ball
%, And smooth polishing was performed by barrel polishing at an amplitude of 20 mm for 60 minutes.

Thereafter, Cu plating and Ni plating were performed under the same conditions as in Example 1. The obtained ring-shaped bonded magnet was subjected to an environmental test (moisture resistance test) under the same conditions as in Example 1. The results and film thickness dimensional accuracy (moisture resistance test) were performed. The results are shown in Tables 2 to 4.

The conductive film processing conditions were as follows: processing time 30 minutes;
The composition of the treatment liquid was 5 wt% of a phenol resin, 5 wt% of Ni powder (particle diameter 0.7 μm or less), and 90 wt% of MEK (methyl ethyl ketone).

[0064]

[Table 1]

[0065]

[Table 2]

[0066]

[Table 3]

[0067]

[Table 4]

From Table 4, rust spots were observed in Comparative Example 1 after about 800 hours, and rust spots were observed in Comparative Example 2 after 600 hours. In contrast, in Example 1, no rust was observed even after 1000 hours under a microscope of 30 times magnification.

[0069]

According to the present invention, a porous R-Fe-B bonded magnet is used as a mixture of an abrasive and a vegetable medium or a mixture of an abrasive and a vegetable medium modified with an inorganic powder as a medium. By applying barrel polishing using a dry method, the ground powder, the inorganic powder and the polishing dust are fixed and sealed in the pores of the R-Fe-B-based bonded magnet with the oil and fat content of the vegetable medium. The R-Fe-B-based bonded magnet can be formed into a spherical, massive, or needle-like (wire) having the required dimensions.
Barrel polishing method using an amorphous metal such as Sn, Zn, Pb, Cd, In, Au, Ag and alloys having a Vickers hardness value of 80 or less in a barrel apparatus by a dry method.
By applying a dry barrel treatment to the surface of the bonded magnet and press-fitting the resin surface and the sealing portion on the surface of the bonded magnet, and coating the surface of the magnetic powder with the metal fine particles to obtain R-Fe-B.
An extremely high conductivity can be imparted by forming the metal coating film on the surface of the bonded magnet, so that a dense and pinhole-free electrolytic plating layer can be formed, and R-Fe- having extremely excellent corrosion resistance can be formed. A B-based bonded magnet can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-276094 (JP, A) JP-A-5-138525 (JP, A) JP-A-7-176443 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01F 1/032-1/08 H01F 41/02

Claims (9)

(57) [Claims] 1. A fixing powder of at least abrasive is ground to a vacancy portion formed in R-Fe-B based bonded magnet table surface in oils and fats of vegetable medium were sealed R- Fe-B series
The permanent magnet surface, and the conductive coating layer of fine pieces of <br/> metal Vickers Hardness of 80 was less attrition conductive by the metallic fine piece
This and a formed through the conductive coating layer electroless plating layer
And R-Fe-B based bonded magnets having high corrosion resistance. 2. The R—Fe—B based bond magnet according to claim 1.
In a stone , the Vickers hardness is reduced to 80 or less metal particles.
Of by conductive coating layer, formed on the magnetic powder surfaces constituting the magnet surface
Characterized in that the thickness of the part which is formed is 1.0 μm or less.
High corrosion resistance R-Fe-B based bonded magnet. 3. The R—Fe—B system according to claim 1 or 2.
In a bonded magnet , gold having a Vickers hardness of 80 or less
Resin surface that forms the magnet surface of the conductive coating layer made of metal particles
High corrosion resistance R-Fe thickness of the upper and cavity portion formed is equal to or is 0.1μm or more 2μm or less
-B-based bonded magnet. 4. An R-Fe-B bond in a dry barrel device.
Mixture or inorganic powder and a magnet, the vegetable medium abrasive
With a mixture of a vegetable medium whose surface has been modified and an abrasive
Produced by grinding with a dry barrel polishing process
At least the abrasive powder is applied to the R-Fe-B permanent magnet surface
Fixed at grease vegetable medium cavity formed, sealing
After the hole, R-Fe-B based bonded magnet dry barrel device
Vickers Hardness is charged with 80 or less amorphous metal strips and,
The irregular shaped metal pieces are ground by dry barrel treatment to produce
After Vickers hardness form is an electrically <br/> conductive coating layer by fine pieces 80 following metals is formed on the magnet surface, the fine pieces of the metal
A method for producing a high corrosion-resistant R-Fe-B-based bonded magnet, wherein electrolytic plating is performed via a conductive coating layer to form an electrolytic plating layer. 5. The R—Fe—B-based bonded magnet according to claim 4.
A method for manufacturing a high corrosion resistant R-Fe-B-based bonded magnet, wherein the abrasive is a ground stone or a metal ball obtained by baking and solidifying an inorganic powder. 6. The R—Fe—B system according to claim 4 or 5.
The method of manufacturing a bonded magnet, it vegetable medium is a core vegetable Kawakuzu, sawdust, fruit shells, corn
A method for producing a high corrosion resistant R-Fe-B-based bonded magnet , characterized by the following . 7. High corrosion resistance R-Fe according to claim 4
In the method for producing a B-based bonded magnet , Vickers hardness
Size 0.1mm~10m is but 80 or less amorphous metal strip
A method for producing a highly corrosion-resistant R-Fe-B-based bonded magnet, wherein the magnet is spherical, massive or needle-shaped. 8. High corrosion resistance R-Fe according to claim 4
In a method of manufacturing a B-based bonded magnet , a dry barrel device is used.
Amorphous metal pieces are crushed and formed by dry barrel processing
High corrosion resistance R-F Vickers hardness, as is characterized in that the size of the fine pieces of 80 or less of the metal is less than the major diameter 5μm
A method for producing an e-B bonded magnet. 9. High corrosion resistance RF according to claim 4
In the manufacturing method of e-B based bonded magnet, rotating, vibrating or
Others are magnets and the Vickers hardness using a centrifugal barrel 80 than
Reduce the volume ratio (magnet / metal) of the lower amorphous metal piece to 3 or less
A high corrosion resistance R characterized by forming a conductive coating layer
-A method for producing an Fe-B based bonded magnet.