JP3139827B2 - Manufacturing method of bonded magnet using rare earth magnetic resin composite material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a bonded magnet using a magnetic resin composite material having excellent oxidation resistance and magnetic properties and excellent moldability using a rare earth-iron-nitrogen material. br />

[0002]

2. Description of the Related Art Bonded magnets are superior to sintered magnets in terms of moldability, can be formed into complex shapes and integrally, are resistant to cracking and cracking, and have good dimensional accuracy. Use range is expanding.

[0003] Among them, the market for bonded magnets having high magnetic properties using Sm-Co-based or Nd-Fe-B-based rare earth magnetic materials is growing rapidly.

[0004] In addition to the above, rare earth-iron-nitrogen based magnetic materials have been invented as rare earth magnetic materials. This material has high magnetic properties even in the case of fine powder of 10 μm or less, in particular, unlike Sm—Co-based or Nd—Fe—B-based materials. If this material having a small particle size is used, a magnetic material-resin composite material having excellent magnetic properties and excellent surface smoothness and mechanical strength and its magnet can be expected.

However, since this material has high magnetism, and has a small particle size and a large specific surface area, agglomeration of magnetic powders is severe and uniform mixing and kneading with a resin are difficult. In particular, in the case of kneading with a thermoplastic resin, the viscosity of the melt becomes high, and uniform kneading is difficult.

Therefore, it has been difficult to obtain a magnetic resin composite material for a bonded magnet, which has insufficient surface coverage of the magnetic powder, has many voids, has high density, and has sufficient corrosion resistance, oxidation resistance and high magnetic properties. .

In particular, in order to obtain a bonded magnet having high magnetic properties, a magnetic field is applied from the outside to magnetically align the magnetic particles. However, if the magnetic powder is strongly agglomerated or the melt viscosity is high, the magnetic field orientation is increased. And the material cannot exhibit the high magnetic force inherent to the material. Further, since the particle size is small, it is easily oxidized during the process, and the magnetic characteristics are greatly deteriorated.

Accordingly, in order to obtain a bonded magnet having high magnetic properties, oxidation resistance, and excellent surface smoothness and dimensional stability, it contains a rare earth-iron-nitrogen system and has an excellent magnetic field orientation. The emergence of a magnetic material-resin composite material having good moldability is strongly desired.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a magnetic material resin which is excellent in magnetic field orientation and oxidation resistance and has good moldability by using a rare earth-iron-nitrogen based magnetic material having fine magnetic properties and high magnetic properties. An object of the present invention is to provide a method for manufacturing a bonded magnet using a composite material.

[0010]

SUMMARY OF THE INVENTION A magnetic material resin composite material having a high density, excellent magnetic field orientation and excellent oxidation resistance using a rare earth-iron-nitrogen based magnetic material having primary particles of fine particles and high magnetic properties. In order to obtain a magnetic powder surface treatment method, resin composition , addition method, kneading method, molding method and a combination thereof, as a result of a thorough study, as a resin component thermoplastic resin and thermosetting resin combined If it is found that it will be a composition with excellent magnetic field orientation and oxidation resistance,
The present invention has been accomplished.

According to the present invention , a surface treatment with a coupling agent is performed.
The rare earth-iron-nitrogen based magnetic powder 80.0 to 99.9% by weight is coated with 0.1 to 20% by weight of a thermosetting resin, and then the magnetic material / resin composite material 80.0 to 99.9 is coated. weight%
Mixing 0.1 to 20 wt% thermoplastic resin and, moreover heat
The total amount of the curable resin and the thermoplastic resin is 0.5 to 20.1
A method for producing a bonded magnet , which comprises injection-molding a magnetic material / resin composite material having a weight percent range .

[0012]

Hereinafter, the present invention will be described in detail.

The rare earth-iron-nitrogen (Re-
The Fe—N) based magnetic material will be described.

As the rare earth (R), Y, La, Ce,
Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
At least one of o, Er, Tm, Yb, and Lu may be included. Therefore, a mixture of two or more rare earth elements such as misch metal and dymium may be used. Preferred rare earths include Y, Nd, Ce, Pr, Sm, G
d, Dy, and Er. More preferably, Y, Nd,
Ce, Pr, and Sm.

Iron (Fe) is the basic composition of the present magnetic material which is responsible for ferromagnetism, but 0.01 to 49 atomic% of Fe is Co,
Ni, Ti, Zr, Hf, V, Nb, Ta, Cr, M
o, W, Mn, Pd, Zn, B, Al, Ga, C, S
It can be replaced by one or more of the elements (M) of i, Ge, and Sn. Among them, Ti, Zr, Hf,
One, two or more of V, Mo, Mn, B, Al, C, Si, and Ge are preferable. More preferably, Z
One or more of r, V, Cr, Mo, B, and C. Hereinafter, when it is described as iron or iron component, Fe
Is replaced by M.

The substitution amount of Fe by M excluding the case of substitution by only one kind of Co is preferably 0.01 to 34.
Atomic%, more preferably 0.1 to 20 atomic%.

It is important that the composition of the rare earth-iron-nitrogen based magnetic material is at least a composition range containing at least rare earth, iron and nitrogen and exhibiting ferromagnetism. In the present invention, in order to obtain high magnetic properties, it is preferable that R is in the composition range of 5 to 20 atomic%, iron component is in the range of 40 to 90 atomic%, and nitrogen (N) is in the composition range of 1 to 25 atomic%. With respect to the composition range, more preferably 2 to 25 atomic%, most preferably 3 to 20 atomic%.
Atomic%.

In addition to nitrogen, the rare earth-iron-nitrogen based magnetic material used in the present invention contains 0.01 to 5 atomic% of hydrogen (H) and 0.01 to 10 atomic% of oxygen (O). In some cases.

The crystal structure of the rare earth-iron-nitrogen magnetic material includes a hexagonal system such as R ₂ Fe ₁₇ N _x type and R ₂ Fe ₁₇ C _Y N _X type, a rhombohedral system, and R ₂ Fe ₁₄ BN _x Type, R ₂ Fe ₁₄
One or more of tetragonal systems such as CN _x type and R (Fe _{1 -Z} M _Z ) ₁₂ N _x type are used. The preferred value of Y is 0.00022 to 3, the atomic ratio of M to iron at this time is 0.001 to 13.6 atomic%, and the preferable value of Z is 0.000012 to 0.33. At this time, the atomic ratio of M to iron is 0.001 atomic% to 33.3.
Atomic%.

Further, apart from the M component, Li, Na,
K, Mg, Ca, Sr, Ba, Ti, Zr, Hf, V,
Nb, Ta, Cr, Mo, W, Mn, Pd, Cu, A
g, Zn, B, Al, Ga, In, C, Si, Ge, S
n, Pb, Bi, and at least one of oxides, fluorides, carbides, nitrides, hydrides, carbonates, sulfates, silicates, chlorides, and nitrates of these elements and R; 0.001 to 4 for iron-nitrogen based magnetic material
It is possible to contain 9% by weight.

The content of the rare earth-iron-nitrogen based magnetic material in the magnetic resin composite material of the present invention is 79.9.
９９99.5% by weight. When the content is less than 79.9% by weight, the residual magnetic flux density is low, the practicability as a permanent magnet is small, and the effect on the magnetic field orientation of the resin in the present invention is small. 9
When the content exceeds 9.5% by weight, the amount of magnetic powder per unit volume increases, but the magnetic field orientation is poor, the residual magnetic flux density is not improved due to the decrease of the resin component, and the amount of resin is small. Poor oxidation resistance because the surface of the powder cannot be coated.
The average particle size of the rare earth-iron-nitrogen based magnetic powder is 0.1 to 80.
It is desirable to be in the range of μm.

In the case of producing a material having particularly excellent dimensional stability and surface smoothness, which are characteristics of the composite magnetic material of the present invention, the average particle diameter is preferably 1 to 10 μm. In order to further increase the density, it is effective to give the particle size an appropriate distribution.

The thermosetting resin in the present invention includes epoxy resin, phenol resin, epoxy-modified phenol resin, unsaturated polyester resin, xylene resin, urea resin, melanin resin, thermosetting silicone resin, alkyd resin, furan resin, A thermosetting acrylic resin, a thermosetting fluororesin, and the like can be given. A reactive diluent such as monoepoxy or a reactive plasticizer is also included in the above. One or two or more of these thermosetting resins are used,
Particularly preferred are epoxy resins and unsaturated polyester resins having well-balanced physical properties such as mechanical strength, chemical resistance, heat resistance, and elasticity. For applications where heat resistance is particularly required, epoxy-modified phenol resins and phenol resins are preferred. The type of resin is selected according to the required performance of the product such as mechanical strength, elasticity, dimensional stability, oil resistance, water resistance, chemical resistance, and weather resistance.

The content of the thermosetting resin of the present invention is from 0.1 to
It must be in the range of 20% by weight. 0.1% by weight
If the amount is less than the above, the effect of the present invention on the magnetic field orientation becomes insufficient.

As the thermoplastic resin in the present invention, 1
Polyamide resins such as 2-nylon, 6-nylon and 6,6-nylon, polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, polyvinyl alcohol, ethylene-acetic acid Polyvinyl resin such as vinyl copolymer, ethylene-ethyl acrylate copolymer, acrylic resin such as polymethyl methacrylate, acrylonitrile, acrylonitrile resin such as acrylonitrile / butadiene / styrene copolymer, polyurethane resin, poly In addition to polyether resins such as ethylene oxide and polyoxymethylene, polyacetal, polycarbonate, polyimide, polysulfone, polybutylene terephthalate, polyethylene terephthalate, polyarylate, poly Engineered plastics such as phenylene oxide, polyether sulfone, polyphenyl sulfide, polyamide imide, polyoxybenzylene, and polyether ketone; liquid crystal resins such as polyaramid, wholly aromatic polyester, wholly aromatic polyether, and polyester amide , Polyamide elastomer, polyester elastomer, thermoplastic elastomer such as polyurethane elastomer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, Polysiloxanes such as fluorine-based resins such as urethane polyfluoride and prepolymers and oligomers of the above resins, silicone oils, silicone greases, silicone resins, etc. And the like, although one or two or more of these resins are used, in particular mechanical strength, elasticity, dimensional accuracy, cost,
12-nylon with good balance of physical properties such as moldability
Polyamide resins such as 6-nylon and 6,6-nylon are suitable components.

The type of the thermoplastic resin can be appropriately selected depending on the required properties of the product such as heat resistance, mechanical strength, elasticity, dimensional stability, oil resistance, water resistance, chemical resistance, weather resistance and the like.

The content of the thermoplastic resin of the present invention is from 0.1 to
It must be in the range of 20% by weight. 0.1% by weight
If the amount is less than the above, the effect of the present invention on the magnetic field orientation becomes small.

The combination of the thermoplastic resin and the thermosetting resin can be freely selected depending on the purpose and required performance, but it is necessary that the total is in the range of 0.5 to 20.1% by weight. If it is less than 0.5% by weight, the mechanical strength is insufficient, and if it is more than 20.1% by weight, the magnetization is reduced, and the magnet is not practical.

Next, a method for producing a magnetic resin composite material used in the method of the present invention will be described.

In general, as a method for producing a bonded magnet, there are a method of injection molding and extrusion molding of a kneaded product of a thermoplastic resin and a magnetic powder, and a method of compression molding a kneaded product of a thermosetting resin and a magnetic powder.

When the rare earth-iron-nitrogen material and the thermoplastic resin are heated and kneaded, the particle size of the rare earth-iron-nitrogen material is 1
Since it is as small as 0 μm or less and has a very high magnetic force, agglomeration is intense, and a combination of a commonly used resin and a kneading method has a high melt viscosity and makes it difficult to obtain a homogeneous magnetic resin composite material. Therefore, when this resin composite material is subjected to magnetic field injection molding, it is difficult to obtain a magnetic field orientation exceeding 80% of the degree of orientation, and high magnetic properties cannot be obtained.

Here, the degree of orientation is defined as σ _a / (σ _a + σ _b ). The degree of orientation is usually expressed as a percentage, in which case the numerical value
I will add% afterwards. However, the residual magnetization in the direction of the magnetic field orientation is σ _a (kG), and the residual magnetization in the perpendicular direction is σ _b (k
G). The higher the degree of orientation is, the closer to 1, the magnetic material-resin composite material having better magnetic field orientation.

Further, oxidative deterioration during kneading and injection becomes severe.

In the case where a thermosetting resin is blended and compression-molded, the magnetic powder is also difficult to be homogeneously kneaded due to agglomeration, and the magnetic field orientation deteriorates during molding, and the degree of orientation is 80%.
The above bonded magnet is difficult to obtain. There is also a problem of thermal deterioration during the curing process.

In order to solve these problems, it is considered that a method of coating the surface of the magnetic powder so that oxidation does not proceed and at the same time improving the slip between the powders is effective.

Therefore, as a method for producing the magnetic resin composite material of the present invention, a thermoplastic resin is added to a thermosetting resin.
Although a simple compounding method is also conceivable, a method having the highest effect on magnetic field orientation and oxidation resistance is a thermosetting resin surface coating method.

Hereinafter, the production method of the present invention will be described.

[0039]

[0040]

[0041]

Thermosetting Resin Surface Coating Method This is a method in which magnetic powder is surface-coated with a thermosetting resin, then kneaded with a thermoplastic resin, and variously molded.

Examples of the method of coating the surface of the thermosetting resin include the following four methods.

(I) Coupling with a solvent in which a resin is dissolved
A method in which a magnetic powder surface-treated with an agent is mixed and the solvent is recovered while kneading; and (ii) a method in which the magnetic powder surface-treated with a coupling agent is formed into a slurry with a solvent and a resin and spray-dried.

(Iii) a method in which a magnetic powder is surface-treated with a coupling agent, and then a resin having a reactivity with an organic chain of the coupling agent is mixed and heat-treated; (iv) a method in which the resin is dissolved in a good solvent and coupling is performed. Surface treatment
This is a method of adding a poor solvent dropwise while dispersing the treated magnetic powder.

In the method (i), almost any resin soluble in a solvent can be used, but a thermosetting silicone resin having an alkoxide in the main chain is a preferred example of this method.

When the solvent is recovered by the method (ii), a resin film is formed on the surface of the magnetic powder, which is particularly preferable. As the method (iii), for example, a method in which a magnetic powder is treated with an amine-based coupling agent to react an amino group introduced on the surface of the magnetic powder with a resin is effective.

When these methods are used, there is an advantage that the oxidative deterioration of the magnetic powder is suppressed even if the magnetic powder is exposed to a high temperature in the step of kneading and injecting with the thermoplastic resin.

The thermosetting resin is preferably an epoxy resin, a phenol-modified epoxy resin, a phenol resin, a thermosetting silicone resin, an unsaturated polyester resin, an alkyd resin, a fluororesin, or the like. Resin, polybutylene terephthalate,
Polyphenylene sulfide, polyether ketone, liquid crystal resin and the like are used.

In the thermosetting resin surface coating method, depending on the combination of the resins, in the case of the magnetic powder used in the present invention, the ratio of the thermosetting resin to the thermoplastic resin and the amount of the curing agent are as follows. Then, a magnetic powder resin composite material having a degree of orientation of 82 to 87% can be obtained.

That is, the curing agent is used in an amount equal to or less than the equivalent, preferably in an amount equal to or less than 0.1.
In the case of a one-pack type thermosetting resin that does not use a curing agent, the amount of addition is 0.1 to the total amount of the composite material.
0.5% by weight, and the amount of the thermosetting resin is 50% by weight or less, preferably 35% by weight or less of the thermoplastic resin.

If the ratio exceeds the above range, the thermosetting resin is cured during kneading, which adversely affects moldability and magnetic field orientation.

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

The advantages of the manufacturing method of the present invention described above are high for the following reasons. If only a thermosetting resin is used for the surface treatment agent and the binder, the reaction between the surface treatment agent and the binder may occur during kneading and molding, or the surface treatment agent may be dissolved and lost. If a thermosetting resin is used as the treatment agent and a thermoplastic resin is used as the binder, the reaction and melting between the resins on the surface of the magnetic powder are alleviated. The magnetic field orientation, oxidation resistance, and good moldability can be obtained.

In order to easily coat the surface of the magnetic powder with a thermosetting resin, it is effective to pretreat the magnetic powder with a coupling agent or a lubricant.

Examples of the coupling agent include isopropyl triisostearoyl titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraisopropyl Isopropyl titanate, tetrabutyl titanate, tetraoctyl bis (ditridecyl phosphite) titanate, isopropyl trioctanoyl titanate, isopropyl tridodecyl benzenesulfonyl titanate, isopropyl tri (dioctyl phosphate) titanate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyl di Methacryl isostearyl titanate, tetra (2,2
Titanium-based coupling agents such as -diallyloxymethyl-1-butyl) bis (ditridecylphosphite) titanate, isopropyltricumylphenyltitanate, bis (dioctylpyrophosphate) oxyacetate titanate, and isopropylisostearoyldiacryl titanate; Aminopropyltriethoxysilane,
N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-glycidoxy-propyltrimethoxysilane, β- (3,4-epoxy-cyclohexyl)
Ethyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris (2-methoxyethoxy) silane,
γ-mercaptopropyltrimethoxysilane, N-β-
(Aminoethyl)-.gamma.-aminopropyl methyl dimethoxy silane, .gamma.-methacryloxypropyl trimethoxysilane, N-(3- triethoxysilylpropyl) urea, methyltrimethoxysilane, octadecyltriethoxysilane La orchid, Biniruto Li acetoxysilane, gamma -Chloropropyltrimethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, γ-chloropropylmethyldimethoxysilane, methyltrichlorosilane, polyalkylene Oxide silanes, coupling agents containing silicon such as perfluoroalkyltrimethoxysilanes and aluminum-based materials such as acetoalkoxyaluminum diisopropylate, One or more kinds of coupling agents such as zirconium, chromium, iron and tin are exemplified.

The type of the coupling agent is selected from those having affinity and reactivity with the resin to be coated on the surface.

Examples of the lubricant include stearic acid, oleic acid, balmitic acid, linoleic acid, lauric acid,
1,2-oxy-stearate, fatty acids such as ricinoleic acid, oleylamine, stearylamine, amines such as lauryl amine, glycine, alanine, aspartic acid, arginine, amino acids histidine, zinc stearate, Karushu stearate U System, barium stearate, aluminum stearate, magnesium stearate, zinc laurate, calcium laurate, zinc ricinoleate, calcium ricinoleate, 2
- Echiruhekisoin zinc fatty acid salts such as stearic acid amide, hydroxystearic acid amide, fatty acid amides such as palmitic acid _{amide, Si 3 N 4, SiC,} Mg
Inorganic compound powders such as O, Al ₂ O ₃ , TiC, Sb ₂ O ₃ ,
One or more kinds of fatty acid esters such as butyl stearate, alcohols such as ethylene glycol and stearyl alcohol, waxes such as paraffin wax, liquid paraffin, polyethylene wax, polypropylene wax, ester wax, carnauba, and micro wax. Can be

The lubricant is used not only for the surface treatment of the magnetic powder but also for kneading to reduce the viscosity of the system and for the magnetic powder to improve the magnetic field orientation and density when it is compounded.

The magnetic material-resin composite material of the present invention may contain a heat stabilizer such as a heat-resistant anti-aging agent and an antioxidant, mainly for improving the heat resistance of the resin.

Examples of the above-mentioned heat aging inhibitor and heat stabilizer include N, N'-hexamethylene-bis (3,5
-Di-tert-butyl-hydroxycinnamic acid amide), 4,
4'-bis (2,6-ditert-butylphenol), 2,
2'-methylenebis (4-ethyl-6-third butylphenol) Various, such as hindered de - phenols, N, N-
Bis (β-naphthyl) -p-phenylenediamine, N,
N'diphenyl-p-phenylenediamine, poly (2,
Aromatic amines such as 2,4-trimethyl-1,2-dihydroquinoline); copper salts such as copper chloride and copper iodide; and sulfur compounds and phosphorus compounds such as dilauryl thiodipropionate.

Further, the magnetic resin composite material of the present invention may contain additives such as a sealant, an ultraviolet absorber, an antistatic agent, a coloring agent, a filler, or a filler such as silica or whisker, if necessary. Can be added.

[0073]

The present invention will be described below in detail with reference to examples.

The evaluation method is as follows.

(1) Magnetic properties The magnetic material-resin composite material is formed into a plate of about 5 × 10 × 2 mm in a magnetic field, or cut out from a large sample to the same size.
This was pulse-magnetized at room temperature at 60 kOe, and then measured using a vibrating sample magnetometer (VSM). The measured magnetic properties are the saturation magnetization 4 when an external magnetic field is applied at 15 kOe.
πIs (kG), residual magnetic flux density Br (kG), squareness ratio B
r / 4πIs (%), coercive force (specific coercive force) iHc (k
Oe), maximum energy product (BH) _max (MGOe),
The degree of orientation σ _a / (σ _a + σ _b ) (%).

(2) Corrosion resistance test The plate-shaped or ring-shaped bonded magnet used in (1) was
The appearance was evaluated according to the following three grades after being left for 96 hours in a thermo-hygrostat at 60 ° C. and a relative humidity of 90%.

；: No rust was generated, Δ: Slight rust was generated, X: Rust was generated (3) Oxidation resistance test The plate-like bonded magnet used in (1) was placed in an oven at 150 ° C. After 20 hours, the magnetic properties were measured in the same manner as in (1), compared with the results in (1), and evaluated by the (BH) max retention (%).

[0078]

[0079]

[0080]

[0081]

[0082]

Example 1 Sm _8.7 Fe having an average particle size of 7 μm
500 g of _73.3 N _14.6 H _0.8 O _2.6 magnetic powder and 2.5 g of γ-aminopropyltriethoxysilane in an isopropanol solution were mixed for 20 minutes by a wet mill, and the magnetic powder and the crushed ball were separated through a sieve. After leaving still for 20 minutes, the mixture was heated under reduced pressure at 150 ° C. for 25 minutes to recover the solvent.

The surface-treated magnetic powder and 5 g of an epoxy resin dissolved in a ketone-based diluent were put into a patch-type kneader and kneaded at room temperature for 30 minutes to evaporate the diluent. At this time, the equivalent ratio between the main agent and the curing agent is 1: 0.5. Next, this magnetic powder was heated under reduced pressure at 80 ° C. for 30 minutes to cause an epoxy resin and an amino group to react on the surface of the magnetic powder. 450 g of this magnetic powder coated with a thermosetting resin and 1
2-Nylon 50 g in a temperature range of 230 to 260 ° C.
The mixture was kneaded using a single-screw extruder adjusted to the surroundings , extruded, and then cut into pellets.

Using these pellets, an injection temperature of 285
Injection molding was performed under the conditions of a temperature of 90 ° C., a mold temperature of 90 ° C., an injection pressure of 1 ton / cm ² , and a magnetic field of 15 kOe. Table 1 shows the evaluation results of the injection-molded bonded magnet.

The appearance of this magnet was a material with no sink marks, gloss and beauty, and good moldability without cracking.

Comparative Example 1 An injection-molded bonded magnet was obtained in the same manner as in Example 1 , except that the surface was not coated with a thermosetting resin. Table 1 shows the results of the evaluation.

The appearance of this magnet is uneven in color.
Sink also saw we were. Moldability was poor, and cracked molded products were found at a rate of 30%, and the whole was a brittle material.

[0089]

[Table 1]

[0090]

As described above, according to the present invention,
A magnetic material-resin composite material containing a rare earth-iron-nitrogen material having a small particle size and high magnetic properties and having high magnetic field orientation, corrosion resistance, and oxidation resistance can be obtained. Thus, a bonded magnet having high magnetic properties and excellent surface smoothness and dimensional stability can be manufactured.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 1/08 C22C 38/00 H01F 1/053

Claims (1)

(57) [Claims] 1. A rare earth-iron-nitrogen based magnetic powder 80.0-99.9% by weight surface-treated with a coupling agent is surface-coated with a thermosetting resin 0.1-20% by weight. magnetic material-resin composite material 80.0 to 99.9 were mixed 0.1 to 20 wt% wt% and the thermoplastic resin, moreover thermosetting tree
The total amount of the fat and the thermoplastic resin is 0.5 to 20.1% by weight.
A method for manufacturing a bonded magnet , which comprises injection-molding a magnetic material-resin composite material within a range .