JP2003257763A - Manufacturing method for rare earth permanent magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple manufacturing method for a high-density R-Fe-B quench bulk magnet of excellent magnet property and high electric resistance. <P>SOLUTION: An insulating-component coated powder is manufactured by forming an insulating layer comprising an insulating component whose volume resistivity is at least 1×10<SP>-1</SP>Ωcm on a surface of each of particles constituting a quench alloy powder for manufacturing an R-Fe-B quench magnet by a dry method in an inert gas atmosphere or in vacuum. Then, the insulating-component coated powder as an initial material is hot molded under a pressure of at least 10 MPa at 400-850°C to obtain a high-density bulk magnet of 6.5 g/cm<SP>3</SP>or higher in density which at least comprises a magnet and an insulating component. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a rare earth-based permanent magnet. More specifically, a densified R-Fe- having excellent magnetic properties and high electric resistance.
The present invention relates to a simple method for producing a B-type quenched bulk magnet.

[0002]

2. Description of the Related Art An amorphous quenched alloy ribbon is obtained from a melted raw material alloy by a melt spinning technique such as a single roll method, and the obtained amorphous quenched alloy ribbon is crushed to obtain an amorphous quenched alloy powder. After that, the R (rare earth element) -Fe-B-based quenching magnet typified by the Nd-Fe-B-based quenching magnet produced by precipitating fine crystals by subjecting this to crystallization heat treatment is a fine crystal. It has excellent magnet characteristics by having grains (magnetic phase). When producing a densified bulk magnet from a quenched magnet powder, if general sintering conditions such as heating to 1000 ° C. or higher under normal pressure are applied, the fine crystal grains in the magnet become coarse, There is a problem that the magnet characteristics are greatly deteriorated. Therefore, in the case of producing a densified bulk magnet from the quenched magnet powder, hot forming is employed in which heating and forming are performed while applying pressure. Hot forming can relax the sintering conditions, especially the sintering temperature, required to obtain a densified bulk magnet, thus suppressing the coarsening of fine crystal grains in the magnet. Thus, it becomes possible to manufacture a densified bulk magnet without deteriorating excellent magnet characteristics.

The densified bulk magnet manufactured in this manner is expected to be used in a rare earth permanent magnet motor. However, the R-Fe-B based permanent magnet has a property of essentially low electric resistance. Therefore, even with a densified bulk magnet having excellent magnet characteristics,
When it is used by incorporating it into a motor, there is a problem that the eddy current loss increases and the motor efficiency decreases.
In order to solve this problem, it is necessary to take measures to increase the electric resistance of the magnet.

As a method of increasing the electric resistance of a densified bulk magnet, a method of separating particles forming a quenched magnet powder from each other by the presence of an insulating component and hot forming has been already proposed, and various studies have been made so far. Has been done. For example, Japanese Unexamined Patent Publication No. 5-121220 discloses a method of hot forming a kneaded product of a quenched magnet powder and an inorganic binder such as borosilicate glass which is an insulating component. JP-A-6-
Japanese Patent Publication No. 69090 describes a method of hot molding a coated powder in which the surface of each particle constituting the quenched magnet powder is coated with a hydrolyzed compound of a metal alkoxide as an insulating component. In Japanese Unexamined Patent Publication No. 9-186010, a quenching magnet powder is mixed with a compound consisting of a fluoride and / or an oxide containing at least one element selected from Li, Na, Mg, Ca, Ba and Sr as an insulating component. Hot forming is described. Japanese Patent Laid-Open No. 9-23221
Japanese Unexamined Patent Publication No. 22-22 describes a method of mixing Ge powder as an insulating component in a quenched magnet powder and performing hot forming.

[0005]

All of the methods proposed so far have some problems. For example, in JP-A-5-121220, as a method for preparing a kneaded product of quenched magnet powder and an insulating component, a method of directly mixing the quenched magnet powder and an insulating component using a ball mill or the like, an insulating component and celluloses A method of mixing a slurry prepared from terpineol or the like with a quenching magnet powder and then heating and drying it, and utilizing a sol-gelation reaction to disperse the quenching magnet powder in a sol liquid containing a raw material of an insulating component and then heating and drying. The method is described. However, among the above methods, it is difficult to form an insulating layer made of an insulating component reliably and uniformly on the surface of each particle constituting the quenched magnet powder by the method of directly mixing, so that the densified bulk When used as a magnet, it may not be possible to provide sufficient electrical resistance. In addition, since the quenched magnet powder may be oxidized (especially when mixed in the atmosphere), the magnetic properties may be deteriorated. In the method of mixing and drying the slurry, at the time of hot forming, the solvent used when creating the slurry remains, which inhibits the progress of densification in the process of densification or reacts with the quenched magnet powder. Doing so may lead to deterioration of magnet characteristics. In the method utilizing the sol-gelation reaction, water or the like contained in the sol solution may cause oxidation of the rapidly cooled magnet powder during heating and drying, resulting in deterioration of magnet characteristics. Since the method described in JP-A-6-69009 is also a method utilizing a sol-gelation reaction, water or the like contained in the sol liquid causes oxidation of the rapidly cooled magnet powder at the time of heating and drying, and deterioration of magnet characteristics. May lead to The method described in JP-A-9-186010 and JP-A-9-23
In the method described in Japanese Patent No. 2122, since the quenched magnet powder and the insulating component are simply mixed, there is a possibility that sufficient electrical resistance cannot be imparted when the densified bulk magnet is used. Therefore, the present invention provides a densified R-Fe-B having excellent magnet characteristics and high electric resistance.
An object of the present invention is to provide a simple method for producing a system quenching bulk magnet.

[0006]

The method for producing a rare earth-based permanent magnet of the present invention, which has been made in view of the above points, is a quench for producing an R-Fe-B-based quenched magnet as set forth in claim 1. By forming an insulating layer composed of an insulating component having a volume resistivity of 1 × 10 ⁻¹ Ω · cm or more on the surface of each particle constituting the alloy powder by a dry method in an inert gas atmosphere or in a vacuum. After preparing the insulating component coating powder, this insulating component coating powder is used as a starting material, and this is hot-molded under the conditions of a pressure of 10 MPa or more and a temperature of 400 ° C. to 850 ° C., and a density of 6.5 g. / Cm ³ or more, which is a densified bulk magnet composed of at least a magnet portion and an insulating component. The manufacturing method according to claim 2 is the manufacturing method according to claim 1, characterized in that the insulating component is at least one selected from rare earth oxides, boron nitride, aluminum nitride, and silicon nitride. Further, the manufacturing method according to claim 3 is characterized in that, in the manufacturing method according to claim 1 or 2, the dry method performed in an inert gas atmosphere or in a vacuum is a vapor phase film forming method. The manufacturing method according to claim 4 is the method according to claims 1 to 3.
In any one of the above-mentioned manufacturing methods, the insulating layer has a thickness of 5 μm or less. Further, the densified R-Fe-B based quenched bulk magnet of the present invention is characterized by being manufactured by the manufacturing method according to any one of claims 1 to 4, as described in claim 5. Further, the insulating component-coated powder of the present invention has a volume resistivity of 1 × on the surface of each particle constituting the quenched alloy powder for producing an R—Fe—B-based quenched magnet as described in claim 6. It is characterized in that an insulating layer made of an insulating component of 10 ⁻¹ Ω · cm or more is formed by a dry method in an inert gas atmosphere or in a vacuum.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a rare earth-based permanent magnet according to the present invention has a volume resistivity of 1 on the surface of each particle constituting a quenched alloy powder for producing an R—Fe—B based quenched magnet. After forming an insulating component-coated powder by forming an insulating layer composed of an insulating component having a density of × 10 ⁻¹ Ω · cm or more in an inert gas atmosphere or in a vacuum, the insulating component-coated powder is used as a starting material. And is hot-molded under the conditions of a pressure of 10 MPa or more and a temperature of 400 ° C. to 850 ° C., and a density of 6.5 g / cm ³ or more, which is at least a magnetic portion and an insulating component. It is characterized in that it is made into a bulk magnet. Insulating component coating powder used as a starting material in the method for producing a rare earth-based permanent magnet of the present invention, since the insulating layer made of an insulating component is formed reliably and uniformly on the surface of each particle,
It becomes possible to easily manufacture a densified R-Fe-B-based quenched bulk magnet having excellent magnet characteristics and high electric resistance.

In the manufacturing method of the present invention, in the case of an R-Fe-B system quenching magnet, a quenching magnet whose magnetic phase is composed only of R ₂ Fe _{1 4} B phase (in many cases, R rich phase is non-magnetic) (Including as a phase), the magnetic phase is R ₂ Fe ₁₄ B
It can also be applied to the production of a nanocomposite magnet composed of a hard magnetic phase such as a phase and a soft magnetic phase such as an iron-based boride phase or an α-Fe phase. Therefore, the composition of the quenched alloy powder used as the starting material may be any as long as it can produce the R—Fe—B based quenched magnet. Of these, the nanocomposite magnet is
Generally, R is 10 atomic% or less, which is smaller than the stoichiometric composition of R ₂ Fe ₁₄ B, and finally the hard magnetic phase constituting the magnet is the R ₂ Fe ₁₄ B phase, Magnetic phase is Fe
Iron-based boride phases such as ₃ B phase and Fe ₂₃ B ₆ phase and α-Fe
Phases are used. In order to improve the magnet characteristics, Co, Al, Si, T are added as additive elements to the quenched alloy.
i, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb,
Various elements such as Mo, Hf, Ta, W, Pt, Pb, Au, and C may be contained.

[0009] Usually, the quenched alloy powder is obtained by crushing an amorphous quenched alloy ribbon formed from a melted raw material alloy by a melt spinning technique such as a single roll method. The individual particles that make up the powder are
Particles having a magnetic phase having an average crystal grain size in the range of 500 nm or less by crystallization heat treatment (individual particles constituting a quenched alloy powder for producing a nanocomposite magnet have an average crystal grain size in the range of 500 nm or less. Particles having a fine structure in which a hard magnetic phase and a soft magnetic phase are mixed and magnetically coupled to each other). The average particle size of the powder is 300 μm
If it exceeds, there is a possibility that densification may not proceed smoothly in the process of densification, so 300 μm or less is desirable and 1
0 μm to 200 μm is more desirable.

Examples of the insulating component having a volume resistivity of 1 × 10 ⁻¹ Ω · cm or more include rare earth oxides such as yttrium oxide (Y ₂ O ₃ ), boron nitride, aluminum nitride and silicon nitride. These have a volume resistivity of 1 × 10
^{Since it is −1} Ω · cm or more, it exhibits sufficient insulating properties in the densified bulk magnet, and has low reactivity with the rapidly-quenched alloy powder under the hot forming conditions described later, so the magnet characteristics (In particular, coercive force: H _cJ ) is not deteriorated.

Using the above quenched alloy powder and insulating component,
An insulating layer composed of an insulating component is formed on the surface of each particle forming the quenched alloy powder by a dry method in an inert gas atmosphere or in a vacuum to prepare an insulating component-coated powder. By hot forming such an insulating component-coated powder, it is possible to make the magnet exhibit high electrical resistance when it is made into a densified bulk magnet. Regarding the amount of the insulating component used, considering the magnetic properties required for the densified bulk magnet (in particular, the residual magnetic flux density: _Br ),
The volume ratio of the magnet portion in the bulk magnet is at least 8
It should be 5% by volume or more, and the higher the ratio, the more desirable. Therefore, the lower limit of the amount of the insulating component used is preferably 1% by volume or more as a volume ratio in the densified bulk magnet from the viewpoint of sufficiently exerting the action, but the upper limit thereof is 15%. It is preferable to use it so as to be a volume%, it is more preferable to use so as to be 10% by volume, and it is further preferable to use so as to be 5% by volume.

Oxidation of the quenched alloy powder is performed by forming the insulating layer on the surface of each particle constituting the quenched alloy powder by a dry method in an atmosphere of an inert gas such as argon gas or nitrogen gas or in vacuum. To prevent the deterioration of the magnet characteristics. Since vapor deposition methods such as plasma CVD (chemical vapor deposition), ion plating and sputtering are performed in an inert gas atmosphere or in vacuum, an insulating layer is formed. The quenched alloy powder does not oxidize during the process. Therefore, it can be said that the formation of the insulating layer by the vapor deposition method is a preferable mode. Further, the quenching alloy powder and the insulating component of the powder (in this case, the average particle size of the powder is 0.01 μm from the viewpoint of uniform dispersibility when mixed with the quenching alloy powder and securing an effective volume of the magnet).
~ 5 μm (when using a flat-shaped powder such as hexagonal boron nitride, it is desirable that the average thickness).
Alternatively, a method of applying mechanical energy to both to form an insulating layer, for example, a high-speed air current impact method or a mechanofusion method may be adopted.

If the thickness of the insulating layer formed on the surface of the individual particles constituting the quenched alloy powder exceeds 5 μm, the effective volume as a magnet becomes small, and the magnet characteristics may be lower than those of the bonded magnet. During the densification process, non-negligible voids remain between the particles forming the insulating component-coated powder, and the voids may hinder the progress of densification. Therefore, the thickness of the insulating layer is preferably 5 μm or less, and more preferably 0.1 μm to 3 μm.

The insulating component coating powder prepared by the above method is used as a starting material, and the pressure is 10MP.
It is hot-formed under the condition of a or more and a temperature of 400 ° C. to 850 ° C. to obtain a densified bulk magnet having a density of 6.5 g / cm ³ or more and at least a magnet portion and an insulating component.
The optimum hot forming conditions should be appropriately set depending on the composition of the quenched alloy powder and the type of insulating component used, but generally, the pressure is set to a desired value for the density of the obtained bulk magnet. From the viewpoint of mold strength, 50 MPa
It is desirable to set the pressure to 500 MPa. On the other hand, the temperature is
It should be set in consideration of the crystallization state of the quenched alloy powder to be hot-formed. For example, in the case of hot-molding an insulating component-coated powder consisting of powder in which 30% by volume or more of individual particles constituting the quenched alloy powder are in an amorphous state, if the temperature is 400 ° C. or higher, it is high even at a relatively low temperature. Densification in the process of densification can be smoothly promoted by the existence ratio of the amorphous state (This phenomenon is due to the nanocomposite magnet having an iron-based boride phase, which is a crystalline phase that is difficult to plastically deform, as a soft magnetic phase. Particularly advantageous in the case of hot forming an insulating component-coated powder consisting of a quenched alloy powder for producing a). However, at a temperature lower than the crystallization temperature of the powder, crystallization of individual particles constituting the powder does not proceed, so that the bulk magnet cannot be used. Therefore, when an insulating component coating powder made of such a quenched alloy powder is used as a starting material and a densified bulk magnet is formed only by hot forming, the temperature of hot forming is the crystallization temperature of the quenched magnet powder ( 550 depending on the composition and heat treatment conditions
C. to 800.degree. C.) to 850.degree. By crystallizing until 90% by volume or more of the magnet portion in the densified bulk magnet is in a crystalline state, it is possible to obtain a densified bulk magnet having more excellent magnet characteristics.
Also, when hot-molding the insulating component-coated powder consisting of powders in which the individual particles that make up the quenched alloy powder have a high crystalline state abundance, the temperature of the hot-molding depends on the composition of the quenched alloy powder and the type used. Depending on the type of insulating component, it is preferably within the range of 550 ° C to 850 ° C, more preferably 60
The temperature is appropriately set within the range of 0 ° C to 750 ° C.

There are 30 individual particles that make up the quenched alloy powder.
When an insulating component-coated powder made of powder in an amorphous state of at least volume% is used as a starting material and a densified bulk magnet is formed only by hot forming, the heat generated by the crystallization reaction causes Attention should be paid to the fact that fine crystal grains in the magnet may be coarsened and the magnet characteristics may be greatly deteriorated due to poor temperature control of the insulating component coating powder inside. Such a situation
Hot compaction is performed under the conditions of a pressure of 10 MPa or more and a temperature of 400 ° C. to the crystallization temperature of the quenched alloy powder, and only the densification in the densification process proceeds to obtain a densified bulk body. 1 crystallization heat treatment for densified bulk
It can be avoided by controlling the temperature at a crystallization temperature of the quenched alloy powder to 850 ° C. under a pressure of MPa or less (for example, in an inert gas atmosphere such as argon gas or nitrogen gas or in vacuum). . As described above, the crystallization temperature of the quenched alloy powder is generally 550 ° C. to 800 ° C., although it varies depending on its composition and heat treatment conditions. In the case of a quenched alloy magnet for producing a nanocomposite magnet, depending on the composition, the crystallization temperature is different between the hard magnetic phase and the soft magnetic phase, and thus the crystallization process is performed in two or more steps, resulting in a differential heat When thermal analysis such as analysis is performed, in some cases, two or more stages of exothermic peaks are observed. In the case of a quenched alloy powder having such a composition, the crystallization temperature of the powder should be based on the crystallization temperature of the crystal phase that crystallizes at the highest temperature.
Therefore, as described above, when performing hot forming and crystallization heat treatment in separate steps, the temperature for performing hot forming is
It is a crystallization temperature of a crystal phase that is crystallized at 400 ° C. to the highest temperature. However, the temperature is preferably 400 ° C. to the crystallization temperature of the crystal phase that crystallizes at the lowest temperature in order to prevent as much heat generation as possible due to the crystallization reaction during hot forming. .

Although various methods for hot forming are known, any of them can be adopted in the present invention. Based on the shape of the bulk magnet and the like, compression molding,
Extrusion molding, roll molding and the like may be appropriately adopted. For example, when performing compression molding, hot press sintering (HP)
A known apparatus such as an apparatus or a spark plasma sintering (SPS) apparatus may be used.

At the time of hot forming, in order to promote the progress of densification and the improvement of magnet strength in the process of high density,
A binder may be added to the starting material. As a binder,
Examples thereof include glassy materials and heat-resistant resins (silicone resin, polyimide resin, etc.) that are easily deformed under the above hot molding conditions and exhibit excellent insulating properties. The binder may be used by being mixed with the insulating component coating powder, for example. When used as a mixture with the insulating component coating powder, the reaction between the quenching alloy powder and the binder (particularly the reaction between R contained in the particles forming the quenching alloy powder and the binder) is reliably suppressed by the presence of the insulating component. To be done. The above-mentioned rare earth oxide, boron nitride, aluminum nitride, silicon nitride and the like are insulating components that effectively suppress the reaction between the quenched alloy powder and the binder.
The total amount of the binder and the amount of the insulating component used is preferably such that the volume ratio in the densified bulk magnet is 15% by volume or less, and 10% by volume or less. It is more desirable to use it, and it is even more desirable to use it so as to be 5% by volume or less.

[0018]

The present invention will be explained in more detail by the following examples, but the present invention is not limited thereto.

Example 1: <Quenched alloy powder> A commercially available MQP-A is used as a quenched alloy powder for producing a Nd-Fe-B system quenched magnet.
(MQI: average particle size is 150 μm and each particle is 9
0 volume% or more crystalline state) was used.

<Sample powder> 1. Powder A MQP-A itself was used as powder A as it was.

2. Powder B A boron nitride-coated powder was obtained by forming an insulating layer of boron nitride (volume resistivity: about 10 ¹⁴ Ω · cm) having an thickness of about 4 μm on the surface of each particle constituting powder A. The powder was designated as powder B. It should be noted that the boron nitride coated powder was prepared by using high frequency plasma C in an argon gas atmosphere.
By the VD method, hexagonal boron nitride powder having an average thickness of about 0.4 μm was used. The obtained boron nitride-coated powder was pulverized and the amount of boron nitride in the powder was measured by a fluorescent X-ray apparatus, and it was about 10% by volume.

3. Powder C Powder A and hexagonal boron nitride powder having an average thickness of about 0.4 μm are uniformly mixed (volume ratio 9: 1), and then powder A is formed by an impact method in a high-speed air stream in an argon gas atmosphere. The thickness of boron nitride on the surface of each particle is about 4 μm
The insulating layer was formed to obtain a boron nitride-coated powder, which was designated as powder C.

4. Powder D After spraying a dispersion liquid prepared by dispersing hexagonal boron nitride powder having an average thickness of about 0.4 μm in ethanol to powder A stirred in flowing argon gas with a spray, and then in an argon gas atmosphere. , Dried at 100 ℃ for 10 minutes, powder A
A powder obtained by depositing boron nitride on the surface of each particle constituting the powder A having a volume ratio of boron nitride of 9: 1 and the powder was designated as powder D.

5. Powder E Powder A and hexagonal boron nitride powder having an average thickness of about 0.4 μm were uniformly mixed using a ball mill in an argon gas atmosphere (volume ratio 9: 1), and the obtained powder was designated as Powder E. .

<Manufacturing Examples 1 to 5 of Bulk Magnet> Using the above-mentioned five kinds of powder A to powder E, a cylindrical bulk magnet having a diameter of 20 mm was manufactured from 35 g of each powder. Hot forming was performed by compression molding using a discharge plasma sintering device. Specifically, as shown in FIG. 1, a die made of a cemented carbide die having a sleeve provided inside and a punch made of cemented carbide is used, and after this die is filled with the quenched alloy powder, The apparatus was set in a spark plasma sintering apparatus, the pressure inside the apparatus was reduced to 1 Pa or less, and pulse current sintering was performed under a pressure of 196 MPa. Temperature rising rate in pulse current sintering is 40 ° C / m
After being kept at in and held at 650 ° C. for 5 minutes, the energization was stopped and then allowed to cool to obtain a bulk magnet. The temperature at the time of spark plasma sintering was measured by forming a hole in the die up to the portion in contact with the sleeve and inserting a thermocouple into the hole.

<Evaluation of Bulk Magnet> Production Examples 1 to 5 above
The 5 types of bulk magnets obtained in 1. were cut and polished, and a cube-shaped test piece of 5 mm × 5 mm × 5 mm was prepared from each of the bulk magnets, and the density was determined from the dimensions and weight. Also,
This test piece was magnetized using a pulse magnetic field of 3.2 MA / m, and its magnet characteristics were measured using a BH tracer. Further, 5 types of bulk magnets were cut and polished to form a rectangular parallelepiped test piece of 5 mm × 5 mm × 15 mm from each bulk magnet, and the specific resistance of this test piece was measured by a four-terminal method. The results are shown in Table 1.

[0027]

[Table 1]

As is clear from Table 1, the bulk magnets obtained in Production Examples 2 and 3 are powder B and powder C, that is, powder A.
It is produced by using as a starting material a boron nitride-coated powder in which an insulating layer made of boron nitride, which is an insulating component, is formed on the surface of each particle that constitutes It has an electric resistance and a density of 6.
The bulk magnet had a high density of 5 g / cm ³ or more. On the other hand, the bulk magnet obtained in Production Example 1 is manufactured using the powder A as a starting material, but it is excellent in terms of magnet characteristics and densification because it does not use an insulating component. However, it had the drawback of low electrical resistance. The bulk magnet obtained in Production Example 4 was produced using Powder D as a starting material.
Since the deposition of boron nitride on the surface of each of the particles constituting the above was carried out by a wet method, the powder A was oxidized, so that it had a defect that the magnet characteristics were inferior. The bulk magnet obtained in Production Example 5 was produced by using the powder E as a starting material, but an insulating layer made of boron nitride was formed on the surface of each particle constituting the powder A reliably and uniformly. Since it could not be formed, sufficient electric resistance was not imparted.

Example 2: Absolute pressure of 30 kPa
Chromium with a thickness of 5 μm to 15 μm in a Lgon gas atmosphere
A cooling alloy made of copper alloy with a diameter of 350 mm and a plating layer
Rotating at a peripheral speed of 15 m / min for single roll method
Therefore, Nd_TwoFe₁₄B (hard magnetic phase) and Fe_ThreeB (soft
Magnetic phase) and a nanocomposite magnet composed of
Nd for _5.5Fe₆₆B_18.5Co₅Cr₅of
A quenched alloy ribbon having a composition was prepared. Quenching obtained
When the gold ribbon was observed with a transmission electron microscope, it was almost 100
% Was amorphous. In addition, crystallization of this quenched alloy thin body
Temperature was measured using a differential scanning calorimeter (DSC)
However, it was 570 ° C. This amorphous quenched alloy ribbon
Grinded using power mill and bin disc mill
After that, the particle size is adjusted and the average particle size is about 75 μm.
A quenched alloy powder was obtained. Prepare powder B in Example 1
This amorphous quenched alloy powder is prepared by the same method as
Is boron nitride as an insulating component on the surface of each constituent particle?
Coating of boron nitride with a thickness of about 4 μm
A powder was obtained, which was used as a starting material in Example 1
A bulk magnet was manufactured in the same manner as in. This bulk magnet
Was evaluated in the same manner as in Example 1, and was excellent.
It has magnet characteristics, high electrical resistance, and density
6.5 g / cm^ThreeThese are bulk magnets with high density
It was.

[0030]

According to the present invention, there is provided a simple method for producing a densified R-Fe-B-based quenched bulk magnet having excellent magnet characteristics and high electric resistance.

[Brief description of drawings]

FIG. 1 is a schematic diagram (partial perspective view) of a mold used to manufacture a bulk magnet in an example.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01F 1/08 H01F 1/08 AF Term (reference) 4K018 AA27 BA18 BC25 BC28 DA31 DA32 EA01 EA21 KA45 5E040 AA04 BC01 BC08 CA01 HB07 HB11 HB17 NN05 NN18 5E062 CC05 CD04 CE04 CG02 CG03 CG07

Claims (6)

[Claims] 1. An insulation comprising an insulating component having a volume resistivity of 1 × 10 ⁻¹ Ω · cm or more on the surface of each particle constituting a quenched alloy powder for producing an R—Fe—B system quenched magnet. After forming the insulating component coating powder by forming the layer by a dry method in an inert gas atmosphere or in a vacuum, this insulating component coating powder is used as a starting material, and the pressure is 10 MPa or more and the temperature is 400 MPa or more. ℃ ~ 850 ℃
The method for producing a rare earth-based permanent magnet, comprising hot-forming under the conditions described above to obtain a densified bulk magnet having a density of 6.5 g / cm ³ or more and at least a magnet portion and an insulating component. 2. The method according to claim 1, wherein the insulating component is at least one selected from rare earth oxides, boron nitride, aluminum nitride, and silicon nitride. 3. The manufacturing method according to claim 1, wherein the dry method performed in an inert gas atmosphere or in a vacuum is a vapor phase film forming method. 4. The manufacturing method according to claim 1, wherein the thickness of the insulating layer is 5 μm or less. 5. A densified R-Fe- which is manufactured by the manufacturing method according to any one of claims 1 to 4.
B type quench bulk magnet. 6. An insulation comprising an insulating component having a volume resistivity of 1 × 10 ⁻¹ Ω · cm or more on the surface of each particle constituting a quenched alloy powder for producing an R—Fe—B system quenched magnet. An insulating component coating powder, wherein the layer is formed by a dry method in an inert gas atmosphere or in a vacuum.