JPH07320968A - Manufacture of rare-earth-fe-n bond magnet - Google Patents

Abstract

PURPOSE:To simplify the manufacturing process of a rare-earth-Fe-N bond magnet and shorten the manufacturing time of the magnet so as to reduce the manufacturing cost of the magnet by unifying the pulverizing process and kneading process of the manufacturing process. CONSTITUTION:A rare-earth-Fe-N bond magnet manufacturing process includes a pulverizing and kneading process in which the pulverization of a magnetic material for a rare-earth-Fe-N bond magnet put in a prescribed container together with a binder and grinding beads and kneading of the pulverized magnetic material are simultaneously performed practically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rare earth-iron-nitrogen based bonded magnet.

[0002]

2. Description of the Related Art The following steps are mentioned as a method for producing a rare earth-iron-nitrogen based bonded magnet.

1) Mother alloy preparation step 2) Coarse crushing step 3) Nitriding step 4) Fine crushing (single domain formation) step 5) Kneading step by adding binder 6) Forming step Rare earth-iron-nitrogen based magnetic material is mother It is known that by introducing nitrogen into the alloy in an interstitial type, strong uniaxial magnetic anisotropy is exhibited and Curie temperature and saturation magnetization are improved. The nitriding treatment is performed by heat treatment in an atmosphere gas such as nitrogen gas, ammonia gas, hydrogen-nitrogen mixed gas, hydrogen-ammonia mixed gas. (For example, Japanese Patent Application Laid-Open No. 2-57663) Further, the coercive force expression mechanism of the rare earth-iron-nitrogen based magnetic material is a new generation type, and in order to obtain a high coercive force, it is finely pulverized into a single domain particle size. Is required, so 1-
Grinding is performed to a particle size of about 5 μm.

Conventionally, rare earth-iron-nitrogen based bonded magnets are
It is prepared by finely pulverizing a rare earth-iron-nitrogen based magnetic material to the above particle size, adding a binder component, kneading, and molding the obtained compound in a magnetic field.

On the other hand, for the reasons described above, it is necessary to finely pulverize the rare earth-iron-nitrogen based magnetic material into single domain particle diameters.
At this time, since the pulverized fine powder is very active,
Oxidation reaction proceeds in the presence of oxygen. Especially, when heat is generated during the crushing step, the kneading step, etc., the oxidation reaction is promoted. In rare earth-iron-nitrogen based magnetic materials,
Since it is decomposed into rare earth oxides and αFe by oxidation, the magnetic properties are deteriorated. In order to avoid such deterioration of magnetic properties, the crushing step and the kneading step have been performed in a non-oxidizing atmosphere such as an inert atmosphere, a reducing atmosphere, or a vacuum atmosphere.

[0006]

However, in such a conventional manufacturing method, since the crushing step and the kneading step are separate steps, it is necessary to make the apparatus used in each step a non-oxidizing atmosphere. .

Furthermore, it is necessary to take the same anti-oxidation measure when the sample is carried in and out between both steps.
Regarding the crushing process and the kneading process, there is a problem that the manufacturing process becomes very complicated. Further, this has been an obstacle to shortening the process time and cost.

The present invention considers such problems of the conventional method for manufacturing a rare earth-iron-nitrogen based bonded magnet, and further simplifies the manufacturing process, shortens the process time and reduces the cost. An object of the present invention is to provide a method for manufacturing a rare earth-iron-nitrogen based bonded magnet that can be reduced.

[0009]

According to the present invention of claim 1, there is provided a method for producing a rare earth-iron-nitrogen based bonded magnet using a rare earth-iron-nitrogen based magnetic material, wherein the rare earth-iron-nitrogen based magnetic material is used. A binder is put into a predetermined container together with a crushing bead, and the rare earth-iron-nitrogen based magnetic material is finely pulverized, and the rare earth-iron-nitrogen based magnetic material and the binder are pulverized or pulverized. Is a method for producing a rare earth-iron-nitrogen bond magnet, which comprises a fine pulverization / kneading step of substantially simultaneously kneading.

According to the present invention of claim 2, the binder is
It is a thermosetting resin, and the finely pulverizing / kneading step is a step performed using a solvent for dilution, and the finely pulverized rare earth-iron-rare earth for adsorbing the thermosetting resin on the nitrogen-based magnetic material surface. -Iron-Nitrogen bond magnet manufacturing method.

According to a third aspect of the present invention, the binder is
A method for producing a rare earth-iron-nitrogen bond magnet, which is a thermoplastic resin, in which the finely pulverized rare earth-iron-nitrogen magnetic material and the thermoplastic resin are mixed and adhered by the fine pulverization / kneading step. .

[0012]

In the present invention, for example, a rare earth-iron-nitrogen based magnetic material, a thermosetting resin and a diluting solvent are put into a pot together with a crushing bead, finely crushed, and the surface of the fine powder particles is heated. Adsorb curable resin or rare earth-
The iron-nitrogen based magnetic material and the thermoplastic resin are put into a pot together with a crushing bead, and finely pulverized by a dry method, and fine powder particles and the thermoplastic resin are mixed and adhered to each other, whereby the pulverizing step and the kneading step. Unification can be realized.

[0013]

EXAMPLES Examples of the present invention will be described below with reference to the tables.

(Embodiment 1) First, an embodiment according to the present invention will be described.

As raw materials, Sm having a purity of 99.9% and electrolytic iron having a purity of 99.99% were used for melting in a high-frequency melting furnace and poured into a carbon mold to prepare an ingot.

The resulting ingot was homogenized in an Ar atmosphere having a purity of 99.99% at 1200 ° C. for 12 hours, and the composition was Sm: 10.5 atomic percent, Fe: 89.5 atomic percent. An alloy was prepared.

The prepared master alloy was coarsely crushed in a nitrogen-substituted glove box to have a particle size of 100 μm or less. At this time, the oxygen concentration in the glow box was 10 ppm or less.

Next, the obtained sample powder was charged with hydrogen: 0.
6. Ammonia: Nitrogen treatment was performed for 1 h at 460 ° C. in a hydrogen-ammonia mixed gas atmosphere with a ratio of 0.4.

After the nitriding treatment, the fine pulverization / kneading process was performed using a rotary ball mill. The solid epoxy resin and the latent curing agent were dissolved in methyl ethyl ketone to obtain a solution. This solution, stainless beads (diameter 1 to 10 mm) as the beads for crushing of the present invention and sample powder were put into a stainless pot, the inside of the pot was replaced with nitrogen, and then fine pulverization and kneading were simultaneously performed. . After this fine pulverization / kneading step, the stainless beads were removed by sieving, and the compound was obtained by drying in a nitrogen atmosphere. The obtained compound was compression-molded in a magnetic field of 19 kOe at a pressure of 10 ton / cm @ 2 and then cured at 160 DEG C. for 1 hour to prepare a bonded magnet.

Comparative Example 1 Next, a comparative example with respect to Example 1 will be described.

The nitriding powder is finely pulverized in a nitrogen atmosphere using a rotary ball mill (fine pulverization step), and then the solid epoxy resin and the latent curing agent are immersed in a solution in which methyl ethyl ketone is dissolved and stirred to form the resin. A bonded magnet was prepared in the same manner as in Example 1 except that it was carried out by an individual process such as adsorption (kneading process).

(Embodiment 2) Next, another embodiment according to the present invention will be described.

Sample powders were prepared in the same manner as in Example 1 up to the nitriding process. The obtained sample powder, polyamide resin, and stainless steel beads (diameter: 1 to 10 mm) were put into a stainless steel pot, the inside of the pot was replaced with nitrogen, and then a fine pulverization / mixing step was performed to obtain a compound. The obtained compound was applied with a magnetic field of 15 kOe, mold temperature 100 ° C., injection temperature 280 ° C., injection pressure 750 kg.
Injection molding was performed at / cm 2 to prepare a bonded magnet.

Comparative Example 2 Next, a comparative example with respect to Example 2 will be described.

The nitriding powder was finely pulverized in a nitrogen atmosphere using a rotary ball mill (fine pulverization step), and the obtained sample powder and polyamide resin were kneaded with a kneader at 260 ° C. to form a compound. A bonded magnet was prepared in the same manner as in Example 2 above, except for the individual step of preparing (kneading step).

The magnetic characteristics of the bond magnet produced as described above were measured using a VSM with a maximum applied magnetic field of 15 kOe. The results are shown in (Table 1). here,
(Table 1) is a table showing the magnetic characteristics of the bonded magnets in the examples and the comparative examples.

[0027]

[Table 1]

As can be seen from (Table 1), the bonded magnets produced in Example 1 and Comparative Example 1 and in Example 2 and Comparative Example 2 exhibited almost the same magnetic characteristics and the coercive force value. Since they are equivalent to each other, it can be said that they are sufficiently pulverized in Examples 1 and 2.

As described above, in the above embodiment, it is possible to realize the unification of the fine pulverization step and the kneading step including the operation of mixing the binder and the like.

As described above, according to the above-mentioned embodiment, the rare earth-iron-nitrogen based magnetic material, the thermosetting resin and the diluting solvent are put into the pot together with the grinding beads and finely ground and the resin By adsorbing the rare earth-iron-nitrogen based magnetic material and a thermoplastic resin into a pot together with a grinding bead, and finely grinding and adhering the resin to form a fine grinding step. Enables unification of kneading process. This simplifies the manufacturing process,
It is possible to shorten the time or reduce the equipment cost,
Enables reduction of manufacturing cost.

The thermosetting resin used in the above examples is effective as long as it can be diluted with a solvent or the like, and the kind and content thereof are not limited.

Further, the thermoplastic resin used in the above-mentioned examples is only required to have a melting temperature lower than 600 ° C. which is the decomposition temperature of the rare earth-iron-nitrogen based magnetic material for the reason described later. Anything can be used, and its type and content do not matter. Here, the above reason is as follows. That is, in the rare earth-iron-nitrogen based magnetic material, a disproportionation reaction occurs at 600 ° C. or higher and SmN
And decomposes into αFe. Rare earth-iron-
This is because the magnetic characteristics of the nitrogen-based magnetic material are significantly deteriorated.

The apparatus used in the fine pulverization / kneading step is not particularly limited as long as it can be finely pulverized to 1 to 5 μm by using a bead for pulverization. For example, a rotary ball mill or a vibration ball mill. Lumil, planetary ball mill, attritor
Various ball mills and the like can be used.

[0034]

As is apparent from the above description,
The present invention has an advantage that the manufacturing process can be further simplified as compared with the conventional method.

Claims (3)

[Claims] 1. A method of manufacturing a rare earth-iron-nitrogen based bonded magnet using a rare earth-iron-nitrogen based magnetic material, wherein the rare earth-iron-nitrogen based magnetic material and a binder are used for grinding.
Into a predetermined container together with the powder, finely pulverizing the rare earth-iron-nitrogen based magnetic material, and kneading the rare earth-iron-nitrogen based magnetic material and the finely pulverized rare earth-iron-nitrogen based magnetic material with the binder. A method for producing a rare earth-iron-nitrogen based bonded magnet, characterized in that it is provided with a fine pulverization / kneading step which is performed simultaneously with the above. 2. The binder is a thermosetting resin,
The rare earth element according to claim 1, wherein the finely pulverizing / kneading step is performed using a diluent solvent to adsorb the thermosetting resin on the surface of the finely pulverized rare earth-iron-nitrogen based magnetic material. -A method for manufacturing an iron-nitrogen based bonded magnet. 3. The binder is a thermoplastic resin,
The rare earth-iron-nitrogen based bonded magnet according to claim 1, wherein the finely pulverized rare earth-iron-nitrogen based magnetic material and the thermoplastic resin are mixed and adhered by the fine pulverization / kneading step. Production method.