JP2002110410A - Rare earth hybrid magnet composition and magnet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rare earth hybrid magnet composition which is composed of R-Fe-N magnetic powder and ferrite magnetic powder, capable of restraining a magnet from deteriorating in magnetic properties when it is manufactured from the composition, inexpensive, and excellent in rectangularity and environmental resistance, and a magnet formed of the same. SOLUTION: A rare earth hybrid magnet composition is composed of rare earth magnetic powder and ferrite magnetic powder, where the ferrite magnetic powder having a specific coercive force is selected, and the rare earth magnetic powder is subjected to a surface treatment by the use of a special surface treating agent. A magnet formed of the above magnet composition is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare earth hybrid magnet composition and a magnet using the same. The present invention relates to a rare earth hybrid magnet composition comprising a rare earth magnetic powder and a ferrite magnetic powder having excellent environmental resistance and a magnet using the same.

[0002]

2. Description of the Related Art In recent years, various permanent magnets used in various fields from miscellaneous goods to motors and sensors have been developed. Such permanent magnets are classified into the following various types according to differences in magnetic materials, manufacturing methods, characteristics, and the like.
That is, when classified by magnetic material, ferrite and Sm-
There are rare earth-based magnetic materials such as Co-based and Nd-Fe-B-based, and metal magnetic materials such as alnico and iron-chromium-cobalt. Also, when classified by manufacturing method, there are sintered magnets, bonded magnets made of magnetic powder and resin binder, and cast magnets.
Bonded magnets can be further molded by injection molding,
They can be classified into extruded magnets, compression molded magnets, rolled magnets, etc. Further, according to the direction of magnetization, it can be classified into an isotropic magnet that can be magnetized in an arbitrary direction by magnetization, and an anisotropic magnet that is magnetized and used in a certain direction determined at the time of manufacturing the magnet. .

In general, sintered magnets can be densified to a relative density of 90% or more by applying a powder metallurgy technique, so that the magnetic force of the material can be extracted as it is, but the degree of freedom in shape is small and the mechanical strength is poor. Have a point. In contrast,
Bonded magnets are made of magnetic powder using resin as a binder, so although there is a reduction in magnetic force equivalent to the resin volume, it has excellent shape flexibility and mechanical strength, and it can be integrally molded with other parts. With the advantages of

On the other hand, the magnetic properties of permanent magnets
Can be widely selected depending on the combination of the manufacturing method. example
For example, if it is a ferrite magnetic powder bonded magnet, 16 kJ
/ M ³36 kJ / m for ferrite sintered magnets³
It is possible to obtain up to a maximum energy product.
If higher magnetic properties are required, use a low-cost ferrule.
More expensive rare earth magnetic materials are used in place of magnetic powder
Used. For example, Sm-Co-based or Nd-Fe-
95kJ / m for B type bonded magnet³, Sm-Co system
Or 430 kJ / Nd-Fe-B based sintered magnet
m³It is possible to obtain the maximum energy product up to
You. In addition, the maximum energy product is 16 kJ / m³~ 100k
J / m³In the middle range, it is inexpensive and has arbitrary magnetic properties
Selectable ferrite magnetic powder and rare earth magnetic material
Proposal of mixed bonded magnets, so-called hybrid magnets
Have been. For example, JP-A-55-99703,
JP-A-57-39102, JP-A-60-2230
No. 95 discloses a ferrite magnetic powder and an Sm-Co-based powder.
A hybrid magnet comprising a magnetic powder has been disclosed.
JP-A-61-284906 and JP-A-62-2
No. 57703, JP-A-10-223421, etc.
Include ferrite magnetic powder and Nd-Fe-B magnetic powder
A hybrid magnet comprising:

However, in the above-described hybrid magnet, when the Sm-Co-based magnetic powder is used, the magnetization of the magnetic powder is small, and when the Nd-Fe-B-based magnetic powder is used, the saturation of the magnetic powder is reduced. Although the magnetization is large, since the magnetic powder is isotropic and the residual magnetization is small, the amount of rare earth magnetic powder to be mixed to obtain the desired magnetic characteristics increases in each case, and the cost is reduced as expected. Did not. In the case of Sm-Co based magnetic powder, expensive Co
, The cost is higher than in the case of Nd-Fe-B-based magnet powder.

On the other hand, as other rare earth magnetic materials, R-Fe-N (R is a rare earth element) magnetic material having a rhombohedral or hexagonal crystal structure in which nitrogen is introduced into an intermetallic compound is used. In particular, it has attracted attention because of its excellent magnetic properties as a permanent magnet material.
Japanese Patent Application Laid-Open No. 2-57663 discloses a magnetic anisotropy represented by R—Fe—N—H (R: at least one of rare earth elements including yttrium) having a hexagonal or rhombohedral crystal structure. Materials are disclosed.

[0007] Further, Japanese Patent Laid-Open No.
Japanese Patent Publication No. 0-21615 discloses a composition for a hybrid magnet and a magnet comprising a powder of the R-Fe-N-based magnetic material and a ferrite magnetic powder.
JP-A-124018 also discloses an injection-molded article comprising an R-Fe-N-based magnetic powder and a ferrite magnetic powder. However, these hybrid magnets have
Compared with conventional magnets using Sm-Co-based magnetic powder or Nd-Fe-B-based magnetic powder, there was a problem that the squareness and environmental resistance of the demagnetization curve were not sufficient.

Incidentally, a general index representing the squareness ratio is represented by the formula: Hk / HcJ (where Hk is the demagnetizing field when the magnetization J becomes 90% of the residual magnetic flux density Br.
J is the intrinsic coercive force. ) Is used, but in the case of a hybrid magnet composed of a rare earth magnetic powder and a ferrite magnetic powder, a bending point occurs on the JH demagnetization curve because the coercive force of each magnetic powder is considerably different. In some cases, Hk / HcJ is not a sufficient indicator of squareness. Therefore, instead of the above ratio, the present inventors use the following formula: μ ₀ H as a square ratio representing the squareness of the demagnetization curve.
cB / Br (where, μ ₀ is the magnetic permeability of vacuum 4π × 10 ⁻⁷⁾
H / m and Hc are coercive force, B is magnetic flux density, and Br is residual magnetic flux density. ) Are proposed. The closer this ratio is to 1, the better the BH demagnetization curve has better squareness, that is, the higher the magnetic properties can be obtained even with a magnet having a low operating point. According to the measurement by the present inventors, in the conventional hybrid magnet of the R-Fe-N-based magnetic powder and the ferrite magnetic powder, the squareness ratio μ
₀ HcB / Br was about 50 to 65%.

The environmental resistance is specifically defined as a high temperature,
It represents durability under high humidity and is a problem related to the entire rare earth magnetic powder. However, only by hybridizing with the ferrite magnetic powder, the environmental resistance of the R—Fe—N magnetic powder was not improved.

Further, the ferrite magnetic powder also has a problem that the coercive force is reduced due to the shear force applied during kneading or injection molding. Similarly, the coercive force is reduced only by hybridizing with the rare earth magnetic powder. The problem did not improve.

As described above, the hybrid magnet obtained by mixing the R-Fe-N-based magnetic powder and the ferrite magnetic powder can be hybridized without eliminating the inherent disadvantages of both magnetic powders. Therefore, although it is extremely advantageous in terms of cost, the squareness of the demagnetization curve is lower than that of a conventional hybrid magnet using Sm-Co-based magnetic powder or Nd-Fe-B-based magnetic powder. Problems such as insufficient and environmental resistance still remain. Therefore, it is necessary to solve these problems of the prior art and to provide a rare earth hybrid magnet which is inexpensive and has excellent squareness and environmental resistance. There was a strong demand for new technological developments.

[0012]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to provide an inexpensive, square, and environmentally resistant magnet with reduced magnetic properties during manufacturing. An object of the present invention is to provide an excellent rare earth hybrid magnet composition comprising a rare earth magnetic powder and a ferrite magnetic powder, and a magnet using the same.

[0013]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a rare earth hybrid magnet composition comprising a rare earth magnetic powder, a ferrite magnetic powder, and a resin binder has: A ferrite magnetic powder having a specific coercive force is selected and R-Fe
The present inventors have found that a desired rare earth hybrid magnet can be obtained by subjecting a -N-based magnetic powder to surface treatment with a specific surface treatment agent, and have completed the present invention.

That is, according to the first aspect of the present invention, a rare earth magnetic powder (A) containing a rare earth element, iron or iron and cobalt, and nitrogen as main components, a ferrite magnetic powder (B), and In the composition for a rare earth hybrid magnet comprising a resin binder (C), the ferrite magnetic powder (B) has a coercive force of 310 kA / m or more, and the rare earth magnetic powder (A) contains a phosphate compound, a silane cup. A composition for a rare earth hybrid magnet, which is surface-treated with at least one type of surface treatment agent (D) selected from the group consisting of a ring agent, an aluminum-based coupling agent, and a titanate-based coupling agent is provided. Is done.

Further, according to the second aspect of the present invention, the first aspect is provided.
The present invention provides a composition for a rare earth hybrid magnet, wherein the amount of the surface treatment agent is 0.1 to 10 parts by weight based on 100 parts by weight of the rare earth magnetic powder.

According to the third aspect of the present invention, the first aspect is provided.
Alternatively, the composition for a rare earth hybrid magnet obtained by the second invention is obtained by an injection molding method, a compression molding method, an extrusion molding method,
Alternatively, there is provided a rare earth hybrid magnet formed by at least one type of forming method selected from a rolling forming method.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

1. Rare earth magnetic powder (A) The rare earth magnetic powder used in the present invention contains a rare earth element (R), iron (Fe) or iron (Fe) and cobalt (Co), and nitrogen (N) as main components. Magnetic powder having a rhombohedral or hexagonal crystal structure (hereinafter referred to as R-
It may be abbreviated as Fe-N-based magnetic powder. ).
The R-Fe-N-based magnetic powder is not particularly limited. For example, JP-A-2-57663, JP-A-3-1610
No. 2, JP-A-3-101102, JP-A-3-101102
141608, JP-A-3-153852,
JP-A-3-160705, JP-A-8-45718
JP, JP-A-8-55712, JP-A-8-14
4024, JP-A-8-316018, JP-A-10-163056, JP-A-10-24192
No. 3, JP-A-10-289811, JP-A-10-289811
It is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-297518.

The R-Fe-N-based magnetic powder is prepared, for example, by manufacturing a nitrogen-free alloy powder by a reduction diffusion method, a melting casting method, a liquid quenching method, etc., as described in the above publication. And heat treatment in an atmosphere containing nitrogen or nitrogen atoms to introduce nitrogen into the alloy powder. Since the rare earth hybrid magnet of the present invention is required to have low cost, it is desirable to use an alloy produced by a reductive diffusion method having a low production cost as a raw material. Examples of the production of magnetic powder by the reduction diffusion method are described in JP-A-5-148517 and JP-A-9-143636.

Incidentally, Japanese Patent Application Laid-Open No. 2-57663,
JP-A-3-16102, JP-A-3-101102
JP, JP-A-3-141608, JP-A-03-
No. 153852, JP-A-03-160705, and the like, rare earth magnetic powders having an average particle size of 1
It is a fine powder of 〜１０10 μm. When such a magnetic powder is used, for example, JP-A-52-54998 and JP-A-59-1 are used in order to improve handling properties such as ignition prevention.
70201, JP-A-60-128202, JP-A-3-2
No. 11203, JP-A-46-7153 and JP-A-56
-55503, JP-A-61-154112, JP-A-3-153
It is preferable to use a magnetic powder having a gradually-oxidized film formed on the surface by wet or dry treatment, as disclosed in, for example, 126801.

2. Ferrite magnetic powder (B) The ferrite magnetic powder (B) used in the present invention has a squareness ratio μ ₀ HcB / Br of the rare earth hybrid magnet of the present invention.
Plays an important role in making the value 65% or more, and its characteristics require that the coercive force be 310 kA / m or more. As described above, the ferrite magnetic powder receives a shearing force in the process of manufacturing the rare-earth hybrid magnet, and the coercive force is greatly reduced due to the strain. That is,
If the coercive force of the ferrite magnetic powder is less than 310 kA / m, a rare-earth hybrid magnet having excellent squareness cannot be obtained.

On the other hand, the specific surface area of the ferrite magnetic powder is not particularly limited, but is usually 1.5 m ² / g or more, preferably 2.0 m ² / g or more, more preferably 3.5 m ² / g or more. is there. Specific surface area is 1.5 m ² / g
If it is less than 1, the squareness ratio μ ₀ HcB / Br is less than 65%.

Further, the compression density of the ferrite magnetic powder is not particularly limited, but is usually 3.3 g / cc or less.
Preferably 2.9 g / cc or less, more preferably 2.
It is 5 g / cc or less. When the compression density exceeds 3.3 g / cc, the squareness ratio μ ₀ HcB / Br is less than 65%. By using the ferrite magnetic powder, a decrease in coercive force during molding is suppressed, and the squareness ratio of the rare earth hybrid magnet is improved, for example, to 70% or more.

The material of the ferrite magnetic powder is Sr
Any of ferrite and Ba ferrite may be used,
In order to enhance the squareness, Sr ferrite is preferable.

As will be described later, when the rare earth hybrid magnet of the present invention is manufactured as an anisotropic bonded magnet,
As the ferrite magnetic powder, in order to enhance the orientation of the magnetic powder in the molding step in a magnetic field, select an anisotropic magnetic powder in which each powder is substantially a single crystal and a shape close to a sphere. It is desirable.

3. Resin Binder (C) The resin binder (C) used in the present invention is not particularly limited, and a usual thermoplastic resin or thermosetting resin can be used.

The thermoplastic resin is not particularly limited. Examples thereof include 6 nylon, 6,6 nylon, 11 nylon, 12 nylon, 6,12 nylon, aromatic nylon, and modified nylon obtained by partially modifying these molecules. Such as polyamide resins, linear polyphenylene sulfide resins,
Cross-linked polyphenylene sulfide resin, semi-cross-linked polyphenylene sulfide resin, low density polyethylene,
Linear low density polyethylene resin, high density polyethylene resin, ultra high molecular weight polyethylene resin, polypropylene resin, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, ionomer resin, polymethylpentene resin, polystyrene resin, acrylonitrile Butadiene-styrene copolymer resin, acrylonitrile-styrene copolymer resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polyvinyl alcohol resin, polyvinyl butyral resin, polyvinyl formal resin, methacryl resin, polyvinylidene fluoride resin, poly Ethylene trifluorochloride resin, ethylene tetrafluoride-hexafluoropropylene copolymer resin, ethylene-tetrafluoroethylene copolymer resin, ethylene tetrafluoride-perfluoroalkyl vinyl ester Ter copolymer resin, polytetrafluoroethylene resin, polycarbonate resin, polyacetal resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyphenylene oxide resin, polyallyl ether allyl sulfone resin, polyether sulfone resin, polyether ether ketone resin, polyarylate Resin, aromatic polyester resin, cellulose acetate resin, homopolymers such as various elastomers and rubbers, random copolymers with other monomers, block copolymers, graft copolymers, end group modification with other substances Goods and the like. In addition, these thermoplastic resins can be used alone or in combination of two or more.

The melt viscosity and molecular weight of the above-mentioned thermoplastic resin are not particularly limited, but it is desirable that the melt viscosity and molecular weight are low as long as the desired mechanical strength is obtained. Although it can be selected, powder is preferred from the viewpoint of uniform mixing with the magnetic powder.

On the other hand, the thermosetting resin is not particularly limited. For example, epoxy resin, vinyl ester epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, urea resin, benzoguanamine resin, bismaleimide triazine resin , Diallyl phthalate resin, furan resin, thermosetting polybutadiene resin,
Examples thereof include a polyimide resin, a polyurethane resin, a silicone resin, and a xylene resin. In addition, these thermosetting resins may be used alone or in combination of two or more kinds, or may be used in combination with other kinds of monomers.

The viscosity, molecular weight, properties and the like of the thermosetting resin are not particularly limited as long as the desired mechanical strength and moldability can be obtained. Powder or liquid is desirable from the viewpoint of moldability.

4. Surface treatment agent (D) In the present invention, the above-mentioned R-Fe-N-based magnetic powder (A) is surface-treated with the surface treatment agent (D). Since the surface of the magnetic powder is covered by this surface treatment, the R-F
The environmental resistance of the e-N-based magnetic powder is improved.

As the surface treatment agent (D), at least one selected from the group consisting of a phosphate compound, a silane coupling agent, an aluminum coupling agent and a titanate coupling agent is used.

The above-mentioned phosphate compound is not particularly limited, but it is important that the phosphate compound itself forms a phosphate after reaction or after non-reaction, and can coat the surface of the R-Fe-N-based magnetic powder. Examples of the phosphate compound satisfying these conditions include commercially available phosphoric acid, a phosphoric acid solution, a phosphate solution, a mixture thereof, and / or a phosphate-based surface treating agent. The phosphate-based surface treatment agent is not particularly limited, and includes, for example, phosphoric acid-based, manganese phosphate-based,
Organic phosphate compounds such as zinc phosphate, sodium hydrogen phosphate, calcium phosphate, and organic phosphate esters are exemplified. In addition, these phosphate compounds can be used alone or in combination of two or more.

The silane coupling agent is not particularly limited, but includes, for example, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4 epoxycyclohexylethyltrimethoxysilane), γ-glycidoxypropyltrimethoxysilane, γ-glycidoxymethyldiethoxysilane, N-β (aminoethyl) γaminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ -Aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane Examples include methoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, and decyltrimethoxysilane. In addition, these silane coupling agents can be used alone or in combination of two or more.

The above-mentioned aluminum-based coupling agents include alkoxyaluminum chelates. For example, acetoalkoxy aluminum diisopropylate and the like. These aluminum coupling agents can be used alone or in combination of two or more.

The above-mentioned titanate-based coupling agent is not particularly restricted but includes, for example, isopropyl triisostearoyl titanate, isopropyl tri (N-aminoethyl) titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraisopropyl bis (Dioctyl phosphite) titanate, tetraisopropyl 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 dimethacryl isostearyl titanate And tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecylphosphite) titanate, isopropyltricumylphenyl titanate, bis (dioctylpyrophosphate) oxyacetate titanate, isopropylisostearoyldiacryl titanate and the like. Can be Among the titanate-based coupling agents, isopropyltriisostearoyl titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis is excellent in adhesion to the surface of the magnetic powder and good in compatibility with the binder component. (Ditridecyl phosphite) titanate and bis (dioctyl pyrophosphate) oxyacetate titanate are particularly preferred. These titanate coupling agents can be used alone or in combination of two or more.

In obtaining the rare earth hybrid magnet composition of the present invention, a surface treatment step is provided in advance to prepare the R-Fe
After subjecting the -N-based magnetic powder to a surface treatment in advance, each magnetic powder is mixed with an organic binder.

The optimum amount of the above-mentioned surface treating agent added to the R-Fe-N-based magnetic powder varies depending on the type.
It is preferably 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the Fe-N-based magnetic powder.
Parts by weight. If the amount added is less than 0.1 part by weight,
If the environmental resistance is not sufficiently improved, and if the amount is more than 10 parts by weight, the density of the molded body is reduced and desired magnetic properties cannot be obtained.

5. Other Additives In addition to the above essential components (A) to (D), additives such as a lubricant and a stabilizer are added to the hybrid magnet composition of the present invention as long as the object of the present invention is not impaired. can do. By the addition of these additives, the heat fluidity of the composition can be further improved, and the moldability and magnetic properties can be improved.

Examples of the lubricant include, but are not particularly limited to, waxes such as paraffin wax, liquid paraffin, polyethylene wax, polypropylene wax, ester wax, carnauba, microwax, stearic acid, 1,2-oxystearic acid, and lauric acid. Acids, fatty acids such as palmitic acid, oleic acid, etc., calcium stearate, barium stearate, magnesium stearate, lithium stearate, zinc stearate, aluminum stearate, calcium laurate, zinc linoleate, calcium ricinoleate, 2-ethylhexoic acid Fatty acid salts such as zinc (metal soaps) stearamide, oleamide, erucamide,
Behenic acid amide, palmitic acid amide, lauric acid amide, hydroxystearic acid amide, methylenebisstearic acid amide, ethylenebisstearic acid amide, ethylenebislauric acid amide, distearyladipamide, ethylenebisoleic acid amide, dioleyladipin Fatty acid amides such as acid amide and N-stearyl stearamide, fatty acid esters such as butyl stearate, alcohols such as ethylene glycol and stearyl alcohol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and poly made of these modified products Polysiloxanes such as ethers, dimethylpolysiloxane, and silicon grease; fluorine compounds such as fluorine-based oils, fluorine-based grease, and fluorine-containing resin powder; silicon nitride Silicon carbide, magnesium oxide, alumina, silicon dioxide, second inorganic compound powder such as molybdenum sulfide and the like, can be used in combination alone or in combination.

The stabilizer is not particularly limited. For example, bis (2,2,6,6-tetramethyl-4)
-Piperidyl) sebacate, bis (1,2,2,6,6)
-Pentamethyl-4-piperidyl) sebacate, 1-
[2- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} ethyl] -4- {3
-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} -2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3- Octyl-1,2,3-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine,
Dimethyl succinate-1- (2-hydroxyethyl) -4
-Hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [[6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4
-Diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [[2,2,6,6
-Tetramethyl-4-piperidyl] imino]], 2-
(3,5-di-tert-butyl-4-hydroxybenzyl)
Bis-n-butylmalonate (1,2,2,6,6-
Hindered amine stabilizers such as pentamethyl-4-piperidyl), or phenolic, phosphite,
Examples thereof include thioether-based antioxidants and the like, and these can be used alone or in combination of two or more.

6. Rare-Earth Hybrid Magnet Composition and Magnet The rare-earth hybrid magnet composition of the present invention comprises a R-Fe-N-based magnetic powder, a ferrite magnetic powder, and a resin binder coated with a specific surface treatment agent as described above. Further, it is prepared by blending other additives as necessary.

The mixing ratio of the R-Fe-N-based magnetic powder, the ferrite magnetic powder, and the resin binder is not particularly limited, and can be appropriately set according to desired magnetic properties. For example, when the (R-Fe-N based magnetic powder weight) / (ferrite magnetic powder weight) ratio is set to a large value to secure desired magnetic characteristics, the mixing ratio of the resin binder can be increased, resulting in an increase. In addition, the fluidity of the composition is improved. On the other hand, if the mixing ratio of the resin binder is set to a low value, the ratio of (R—Fe—N-based magnetic powder weight) / (weight of ferrite magnetic powder) is reduced. In other words, the mixing ratio of ferrite magnetic powder is increased. Thus, raw material costs can be reduced.

The method of mixing and kneading the R—Fe—N-based magnetic powder, the ferrite magnetic powder, and the resin binder is as follows.
Although not particularly limited, for example, a mixer such as a ribbon blender, a tumbler, a Nauter mixer, a Henschel mixer, a super mixer, a planetary mixer, and a Banbury mixer, a kneader, a roll, a kneader ruder, a single screw extruder, and a twin screw extruder And the like.

The composition obtained by mixing and kneading is
Although not particularly limited, injection molding, compression molding, extrusion molding,
Alternatively, the rare earth hybrid magnet of the present invention can be obtained by rolling and forming.

The rare-earth hybrid magnet of the present invention is less expensive, has better environmental resistance and better BH than magnets using conventional Sm-Co based magnetic powder or Nd-Fe-B based magnetic powder.
It has excellent squareness ratio of demagnetization curve, and its industrial value is extremely large.

When the R-Fe-N-based magnetic powder disclosed in Japanese Patent Application Laid-Open No. 2-57663 is used, each powder is an anisotropic magnetic powder in which each powder is substantially a single crystal. Therefore, by molding the composition in a magnetic field, R
-An anisotropic rare earth hybrid magnet having an easy magnetization direction of the Fe-N-based magnetic powder and having a high magnetic flux density can be manufactured. Similarly, for ferrite magnetic powders, anisotropic rare earth hybrid magnets having a uniform magnetic easy direction of ferrite magnetic powders and a high magnetic flux density can be manufactured by selecting anisotropic magnetic powders and molding in a magnetic field. . That is,
By forming a composition produced from an anisotropic R-Fe-N-based magnetic powder and an anisotropic ferrite magnetic powder in a magnetic field, an anisotropic rare earth hybrid magnet having the highest magnetic flux density can be obtained. can get.

On the other hand, the ferrite magnetic powder disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 61-284906 and the like and Nd-F
Hybrid magnets composed of eB-based rare earth magnetic powder have a high mixing ratio of expensive rare earth magnetic powder when obtaining the same magnetic flux density because the Nd-Fe-B based magnetic powder is isotropic. It must be set, and the cost merit of the present invention cannot be obtained.

[0049]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(1) Production of R—Fe—N magnetic powder Electrolytic Fe powder having a purity of 99.9 wt% and a particle size of 150 mesh or less (Tyler standard, the same applies hereinafter) and a purity of 99 wt%.
Oxidized Sm powder having an average particle size of 325 mesh and a purity of 99 w
t% of granular metal Ca was mixed using a V blender. The obtained mixture was placed in a stainless steel container, and heated at 1150 ° C. for 8 hours in an argon atmosphere to cause a reduction diffusion reaction. Next, the reaction product was cooled and then poured into water to disintegrate. The resulting slurry was washed with water, and further washed with acetic acid to remove unreacted Ca and CaO by-produced. The obtained slurry was filtered, replaced with ethanol, and dried under vacuum to obtain an Sm-Fe alloy powder having a size of 150 μm or less. Next, this powder was charged into a tubular furnace, and heated (nitriding) at 465 ° C. for 6 hours in an ammonia-hydrogen mixed gas atmosphere having an ammonia partial pressure of 0.35, and then heated at 465 ° C. for 2 hours in argon gas ( Annealing treatment)
24.6 wt% Sm-3.6 wt% N-bal. An R-Fe-N alloy powder of Fe was obtained. X-ray analysis of this alloy powder showed a diffraction line (Sm ₂ Fe ₁₇ N ₃ intermetallic compound) having a rhombohedral Th ₂ Zn ₁₇ type crystal structure. This powder was added to a Fisher average particle size of 1.6 μm.
Finely pulverized using an impact plate type jet mill and anisotropic Sm
-An Fe-N magnetic powder was obtained. This magnetic powder was used in the following Examples and Comparative Examples.

(2) Preparation of Ferrite Magnetic Powder Four kinds of commercially available ferrite magnetic powders were obtained,
The coercive force, specific surface area, and compression density of each magnetic powder were determined. Table 1 shows the results. The coercive force of the ferrite magnetic powder was measured using a vibrating sample magnetometer in accordance with “Bond magnet test method guidebook BMG-2002 and 2005”, the specific surface area was measured by the BET one-point method, and the compression density was measured by a mold. The magnetic powder was evaluated by apparent density when pressed at 98 MPa.

[0052]

[Table 1]

(3) Evaluation Method Evaluation of Magnetic Properties The obtained rare earth hybrid magnet was
After magnetizing with a pulse magnetic field of 0 kA / m, its magnetic properties were measured at room temperature with a thiophy-type self-recording magnetometer. Environmental resistance evaluation The above rare earth hybrid magnet was subjected to a temperature of 60 ° C. and a humidity of 9
It was put into a constant temperature / humidity chamber set to 0%, the irreversible demagnetization rate after 1000 hours had elapsed was measured, and the environmental resistance was evaluated. If the irreversible demagnetization rate after 1000 hours has passed is less than 5%, the environment resistance is judged to be good.

Examples 1 to 6 and Comparative Examples 1 to 3 According to the description in Table 2, Sm-Fe-N
44% by weight magnetic powder and 46w ferrite magnetic powder
t%, 12 wt% of 12 polyamide resin, the balance being a surface treatment agent, to produce a composition for a rare earth hybrid magnet and a magnet. The magnetic properties and environmental resistance of the obtained rare earth hybrid magnet were evaluated based on the above evaluation methods, and the results shown in Table 3 were obtained.

(Surface Treatment of Magnetic Powder) Each magnetic powder and 12
Prior to mixing and kneading with the polyamide resin, Sm-F
The e-N-based magnetic powder was subjected to a surface treatment. That is, Sm-F
After diluting an organic phosphate compound (trade name: TBP manufactured by Daihachi Chemical Industry Co., Ltd.) in an amount shown in Table 2 with respect to 100 parts by weight of the e-N magnetic powder in an organic solvent system, each magnetic powder was diluted. And 40 rpm, 30 mi in a planetary mixer
n Mix and stir to make a homogeneous mixture, stirring up to 13
Gradually raise the temperature to 0 ° C to allow sufficient reaction.
It dried in this state. Table 2 shows the type of ferrite magnetic powder used and the amount of the surface treating agent mixed with the Sm-Fe-N-based magnetic powder (parts by weight based on 100 parts by weight of the magnetic powder).

[0056]

[Table 2]

(Mixing of Composition and Preparation of Pellets) Each of the obtained magnetic powders and 12 polyamide resins were mixed and kneaded with Labo Plastomill to obtain a composition for a rare earth hybrid magnet. The kneading temperature is 200 to 220 ° C,
The composition taken out after kneading was air-cooled. Next, each of the obtained compositions was pulverized by a plastic pulverizer to obtain molding pellets.

(Preparation of Magnet) Using the above-mentioned molding pellets, injection molding was performed while applying an orientation magnetic field of 560 kA / m in the direction of 7 mm to produce a columnar rare earth hybrid magnet of φ10 × 7 mm. Cylinder temperature is 200-22
0 ° C. and the mold temperature were 80 to 120 ° C.

Examples 7 to 12 and Comparative Examples 4 to 6 An isopropyl triisostearoyl titanate coupling agent (trade name: KRTTS manufactured by Ajinomoto Co., Inc.) was used as a surface treatment agent. Otherwise, the examples are Examples 1 to
Rare-earth hybrid magnets were manufactured in the same manner as Comparative Example 6 and Comparative Examples 1-3. The magnetic properties and environmental resistance of the obtained rare earth hybrid magnet were evaluated by the above-described evaluation methods, and the results shown in Table 4 were obtained.

Examples 13 to 18 and Comparative Examples 7 to 9 An acetoalkoxyaluminum diisopropylate coupling agent (trade name: AL-M, manufactured by Ajinomoto Co., Inc.) was used as a surface treatment agent. Otherwise, the example is Example 1.
Comparative Examples 6 to 6 and Comparative Examples 1 to 3 produced rare earth hybrid magnets. The magnetic properties and environmental resistance of the obtained rare earth hybrid magnet were evaluated by the above-described evaluation methods, and the results shown in Table 5 were obtained.

Examples 19 to 24, Comparative Examples 10 to 12 Vinyltriethoxysilane coupling agent-based treating agents (trade name: A-151, manufactured by Nippon Unicar Co., Ltd.) were used as surface treating agents. Otherwise, the examples are Examples 1 to
Rare-earth hybrid magnets were manufactured in the same manner as Comparative Example 6 and Comparative Examples 1-3. The magnetic properties and environmental resistance of the obtained rare-earth hybrid magnet were evaluated by the above-described evaluation methods, and the results shown in Table 6 were obtained.

[0062]

[Table 3]

[0063]

[Table 4]

[0064]

[Table 5]

[0065]

[Table 6]

As is evident from the results of Tables 3 to 6, the use of the composition for a rare earth hybrid magnet of the present invention makes it possible to produce a rare earth hybrid magnet excellent in environmental resistance and BH demagnetization curve squareness ratio. Became possible.

[0067]

As described above, the composition for a rare earth hybrid magnet of the present invention uses a ferrite magnetic powder having specific characteristics, and further applies a surface treatment to the rare earth magnetic powder with a specific surface treating agent. As a result, the conventional Sm-
Compared with magnets using Co-based magnetic powder or Nd-Fe-B-based magnetic powder, a rare-earth hybrid magnet that is less expensive and has excellent environmental resistance and excellent squareness ratio of BH demagnetization curve can be provided.
Its industrial value is extremely large.

Continued on the front page F term (reference) 4K018 AA11 AA27 AA40 BA05 BA18 BA20 BB10 BC12 BC29 CA09 CA11 CA29 CA31 CA36 KA46 5E040 AA03 AA19 AB03 AC05 BB03 BC05 CA01 HB14 NN03 NN12

Claims (3)

[Claims] 1. A rare earth hybrid magnet comprising a rare earth magnetic powder (A), a ferrite magnetic powder (B), and a resin binder (C) containing a rare earth element, iron or iron and cobalt, and nitrogen as main components. In the composition, the ferrite magnetic powder (B) has a coercive force of 310 kA / m or more, and the rare earth magnetic powder (A) contains a phosphate compound, a silane coupling agent, an aluminum coupling agent, and A composition for a rare earth hybrid magnet, which has been surface-treated with at least one type of surface treatment agent (D) selected from the group consisting of titanate coupling agents. 2. The amount of the surface treatment agent (D) added is 0.1 to 10 parts by weight based on 100 parts by weight of the rare earth magnetic powder (A).
The composition for a rare earth hybrid magnet according to claim 1, wherein the composition is part by weight. 3. The composition for a rare earth hybrid magnet according to claim 1 or 2, which is molded by at least one molding method selected from an injection molding method, a compression molding method, an extrusion molding method, and a rolling molding method. Rare earth hybrid magnet.