JP2003264115A - Manufacturing method for bulk magnet containing rare earth - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method by which both of maintenance for the crystal grain diameter of magnet powder and miniaturization for a magnet are obtained, related to a method for manufacturing a bulk magnet containing rare earth with the magnet powder containing a rare earth element as a raw material. <P>SOLUTION: The magnet powder containing the rare earth element is formed in a magnetic field. Then it is pressure-sintered in this manufacturing method for the bulk magnet containing rare earth. It is desired that a condition for pressure-sintering is so controlled that, provided that a sintering temperature is x(°C) and a pressurizing force is y (tonf/cm<SP>2</SP>), 3.1≤y≤6.0 when 500≤x<650, -0.02x+16.1≤y≤-0.02x+19 when 650≤x≤800, or 0.1≤y≤3.0 when 800<x≤900. <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-containing bulk magnet, and more particularly to a method for manufacturing a rare earth-containing bulk magnet having a dense magnet structure and high coercive force.

[0002]

2. Description of the Related Art Various rare earth-containing magnets have been developed so far, and one of them is manufactured by mixing magnet powder and resin and subjecting them to compression molding.
There are so-called bond magnets. This bonded magnet has a feature that it is easy to apply to many products because it has a high degree of freedom in shape. However, there is a limit to the molding density, and the density is usually the true density of the magnet powder (about 7.7 g / cm).
^It is about 80% of ³ ). Therefore, the maximum energy product (BH) max of the magnet is reduced to about 65% of the magnet powder.

On the other hand, other magnet products include bulk magnets manufactured by molding magnet powder. Bulk magnets can be densified at a higher density than bonded magnets, and bulk magnets having excellent magnet characteristics have been widely developed. The main steps of the bulk magnet manufacturing flow include a step of preparing magnet powder having a predetermined composition, a step of molding a magnet, and a step of sintering the molded magnet.

Generally, as a method for improving the magnet characteristics of the bulk magnet manufactured by the above-mentioned flow, there is a method of densifying to a true density by a liquid phase sintering method.

However, in the liquid phase sintering method, 11
Since it is necessary to heat up to a high temperature of about 00 ° C., it is difficult to keep the crystal structure of the magnet fine. In this case, the coercive force of the magnet deteriorates even if densification is achieved. The HDDR method is known as a method for improving the coercive force of a magnet by reducing the crystal grain size of the magnet powder. However, if the high temperature densification step such as the liquid phase sintering method is performed, the The significance of reducing the particle size is greatly reduced.

[0006]

In view of the above circumstances, the present invention is a method for producing a rare earth-containing bulk magnet using a magnet powder containing a rare earth element as a raw material, and maintaining the crystal grain size of the magnet powder. It is an object of the present invention to provide a manufacturing method that realizes both miniaturization of a magnet and a magnet.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to Nd-Fe-
B-type anisotropic HDDR magnet powder is molded at room temperature in a magnetic field,
This is a method for producing a rare earth-containing bulk magnet, which is characterized by performing pressure sintering thereafter.

The rare earth-containing bulk magnet produced by the method of the present invention is such that the crystal grain size of the magnet powder remains fine and is highly densified. Therefore, a bulk magnet having very excellent magnet characteristics can be obtained.

[0009]

According to the present invention configured as described above, the following effects are obtained for each claim.

The invention according to claim 1 is a method for producing a rare earth-containing bulk magnet, characterized in that magnet powder containing a rare earth element is molded in a magnetic field and then pressure-sintered. By thus sintering while applying pressure, the magnet can be densified. Moreover, the crystal structure of the magnet can be maintained fine. That is, it is possible to obtain a rare earth-containing bulk magnet that is dense and has a fine crystal grain size, and such a bulk magnet has excellent magnet characteristics such as coercive force and maximum energy product.

As the magnet powder, Nd-Fe-B type anisotropic HDDR magnet powder is used. H
The magnet powder manufactured by using the DDR method has a feature that the crystal grain size is extremely fine. Also, HD
Since the DR magnet powder is very hard, it is effective to pressurize and heat it. From these points, it can be said that the present invention is particularly suitable when HDDR magnet powder is used as the magnet powder. Also, neodymium (Nd), iron (Fe)
And by using a Nd-Fe-B magnet powder comprising boron (B) consisting of Nd ₂ Fe ₁₄ B phase as the main phase, thereby to reduce the improvement and material cost of the magnet properties. Furthermore, by manufacturing a bulk magnet using anisotropic magnet powder, a magnet having higher magnet characteristics than an isotropic magnet can be obtained.

The invention described in claim 2 is characterized in that a hot pressing method or a spark plasma sintering method is used as a method of pressure sintering. These methods are excellent in that they can be densified at a temperature lower than the liquid phase sintering temperature.

According to a third aspect of the present invention, when pressure sintering is performed at a sintering temperature of x (° C.) and a pressure of y (tonf / cm ² ), 500 ≦ x <650 and 3. 1 ≦ y ≦ 6.
It is controlled so that it becomes zero. By performing pressure sintering so as to satisfy such conditions, a bulk magnet having excellent magnet characteristics (coercive force, maximum energy product, magnet density, etc.) can be obtained.

According to a fourth aspect of the present invention, when pressure sintering is performed at a sintering temperature of x (° C.) and a pressure of y (tonf / cm ² ), 650 ≦ x ≦ 800 and −0. .02x + 1
The control is performed so that 6.1 ≦ y ≦ −0.02x + 19. That is, when 650 ≦ x ≦ 800, y is controlled so as to be a region between the lower limit of the line segment represented by −0.02x + 16.1 and the upper limit of the line segment represented by −0.02x + 19. It is a thing. By performing pressure sintering to satisfy such conditions, excellent magnet characteristics (coercive force, maximum energy product, magnet density, etc.)
A bulk magnet having is obtained.

According to a fifth aspect of the present invention, when pressure sintering is performed at a sintering temperature of x (° C.) and a pressure of y (tonf / cm ² ), 800 <x ≦ 900 and 0. 1 ≦ y ≦ 3.
It is controlled so that it becomes zero. By performing pressure sintering so as to satisfy such conditions, a bulk magnet having excellent magnet characteristics (coercive force, maximum energy product, magnet density, etc.) can be obtained.

The invention according to claim 6 uses a magnet powder containing 11 to 13 atom% of a rare earth element with respect to the total amount of elements contained in the magnet powder. When the content of the rare earth element contained in the magnet powder is in such a range, a rare earth-containing bulk magnet having excellent magnet characteristics (coercive force, residual magnetic flux density, magnet density, etc.) can be obtained.

The invention according to claim 7 has an average particle size of 1 to
A magnet powder having a size of 500 μm is used. When the average particle size of the magnet powder is in such a range, a rare earth-containing bulk magnet having excellent magnet characteristics (coercive force, residual magnetic flux density, magnet density, etc.) can be obtained.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a magnet powder containing a rare earth element, specifically, an Nd-Fe-B system anisotropic HDDR.
This is a method for producing a rare earth-containing bulk magnet, which comprises molding magnet powder in a magnetic field at room temperature and then pressure sintering.

When the magnet is densified by heating to a high temperature as in the liquid phase sintering method, the crystal grain size of the magnet increases. Therefore, in order to densify the magnet without heating it to an extremely high temperature, a method of densifying by using pressure can be considered. However, during densification by pressurization, dislocations and strains are easily induced inside the magnet powder, and the magnet characteristics, especially the coercive force, are likely to decrease. The present invention has solved this problem by sintering (heating) while pressurizing. That is, by performing pressure sintering, it is possible to suppress dislocations / strains that may occur inside the magnet powder due to pressure application, and to make the magnet dense while maintaining the crystal grain size of the magnet. . Moreover, in order to further enhance the magnetic properties of the obtained rare earth-containing bulk magnet, it is important to select the pressing force and the sintering temperature during pressure sintering.

The method for manufacturing the rare earth-containing bulk magnet of the present invention will be described below by following the manufacturing steps.

First, a magnet powder containing a rare earth element is prepared.
Be prepared. The rare earth element to be contained is particularly limited
Not Neodymium (Nd), Samarium (Sm), LA
Tan (La), cerium (Ce), praseodymium (P
r), gadolinium (Gd), terbium (Tb), di
Sprosium (Dy), Holmium (Ho), Erbiu
Mu (Er), Thulium (Tm), Ytterbium (Y
b), lutetium (Lu), yttrium (Y), etc.
Can be mentioned. The composition is not particularly limited.
However, considering the improvement of magnet characteristics and raw material cost, rare earth
Neodymium (Nd), iron using neodymium as a similar element
Nd consisting of (Fe) and boron (B) ₂Fe₁₄Phase B
Nd-Fe-B system magnet powder containing as a main phase is used.
And are preferred.

There are no particular restrictions on the particle size and particle size distribution of the magnet powder, and various conventionally known magnet powders can be used. It is also possible to apply a commercially available magnet powder or a magnet powder used in producing a bonded magnet. A preferred magnet powder is hydrogen absorption
HDDR that realizes finer crystal grain size by dehydrogenation treatment
HDDR magnet powder that has been subjected to a method. HDDR
The method is not particularly limited, and of course, various improved HDDR methods may be used as long as the crystal grain size can be reduced.

The crystal grain size of the HDDR magnet powder is extremely fine. When the conventional liquid phase sintering method is used, even if the crystal grain size is made fine by the flat angle HDDR method, the crystal grain size increases at the sintering stage.
The effect of the DDR method has been revoked. Also, HD
DR magnet powder has a Vickers hardness of Hv = 600 to 700
Since it can be extremely hard, it is difficult to sufficiently densify it by only pressing force. In this respect, since the present invention employs a sintering (heating) method while applying pressure, densification can be sufficiently promoted even when HDDR magnet powder having high hardness is used.

The composition of the magnet powder is not particularly limited,
In order to improve the magnetic properties of the obtained bulk magnet, the amount of rare earth element contained in the magnet powder is preferably 11 to 13 atom% with respect to all the elements in the magnet powder. When the content of the rare earth element contained in the magnet powder is in such a range, a rare earth-containing bulk magnet having excellent magnet characteristics such as coercive force, residual magnetic flux density and magnet density can be obtained. When the rare earth element content is less than 11 atom%, the main phase (for example, Nd−) of the magnet that is considered to have a coercive force mechanism is considered.
In the case of using Fe-B type magnet powder, Nd ₂ Fe
_The slight Nd-rich phase existing in the grain boundary of ( ₁₄ B phase) may decrease, and the magnet characteristics may deteriorate. On the other hand, when the rare earth element content exceeds 13 atom%, the coercive force is secured, but the proportion of the non-magnetic phase other than the main phase increases, which causes a demerit that the residual magnetic flux density (Br) decreases, and the magnet It may adversely affect the characteristics. The content of the rare earth element can be measured using ICP (inductively coupled plasma optical emission spectrometry) or the like.

Since the magnet powder is an alloy material, it is inevitable that a small amount of impurities will be mixed in, but the smaller the amount of impurities, the better. Specifically, it is preferably 1% by mass or less, more preferably 0.3% by mass or less, and particularly preferably 0.1% by mass or less.

The average particle size of the magnet powder is 1 to 500 μm.
It is preferably m. When the average particle size of the magnet powder is within this range, it is possible to suppress the oxidation of the magnet powder and reduce the deterioration of the magnet characteristics, and it is also effective for densifying the magnet. When the average particle size of the magnet powder is less than 1 μm, the influence of oxidation becomes remarkable, and as a result, the coercive force (HcJ) and the residual magnetic flux density (B
r) may decrease. On the other hand, if the average particle size of the magnet powder exceeds 500 μm, the dispersion of the crystal directions within a single particle becomes large, and the degree of orientation decreases, and as a result, the residual magnetic flux density (Br) may decrease. still,
In order to prevent the oxidation of the magnet powder, it is possible to mix a rust preventive agent, an insulator for improving the electric resistance of the sintered body, and the like with the magnet powder.

Further, when the magnet powder is an anisotropic magnet powder, it is possible to further improve the magnet characteristics of the obtained bulk magnet. When anisotropic magnet powder is used, it is advisable to perform preliminary molding in a magnetic field to improve magnet characteristics before pressure sintering. In terms of maximum energy product, anisotropic magnets molded in a magnetic field are
It can have as many as twice the properties. The reason why such excellent characteristics are exhibited is that the residual magnetic flux density can be increased by aligning the easy axes of magnetization of the magnets.

Next, the prepared magnet powder is filled in a mold, such as a non-magnetic WC mold, which can be applied to the pressurizing condition and the sintering condition to be described later, and temporary molding is performed while applying a magnetic field if necessary. By performing temporary molding in a magnetic field, an anisotropic magnet having excellent magnet characteristics such as maximum energy product can be obtained. The strength of the magnetic field when molding in a magnetic field is 10
It is preferably about -25 kOe.

By using an apparatus in which a mechanism for applying a magnetic field and a pressure sintering apparatus are integrated, there is an advantage that the manufacturing process can be simplified, but the temporary forming apparatus and the pressure sintering apparatus in the magnetic field are independent. There is no problem even if you do. There is no particular limitation on the pressing force at the time of temporary molding, and if it is about 1 to ² tonf / cm ² (weight ton / square centimeter), there is no problem in the subsequent handling. However, 10 tonf / cm
^When an unnecessarily large pressure of about ² or more is applied, a part of the magnet powder is cracked, which may cause a decrease in anisotropy when producing an anisotropic magnet. Of course, when producing an isotropic magnet, it is not necessary to apply a magnetic field, and it is not necessary to prepare an apparatus capable of performing temporary molding in a magnetic field. Temporary forming when producing the isotropic magnet may be performed by a pressure sintering device, and the bulk magnet can be produced without providing a special temporary forming step. The temperature of the temporary molding is not particularly limited, but it is preferably room temperature in consideration of the improvement of the manufacturing efficiency and the cost reduction by simplifying the manufacturing process. The atmosphere at the time of temporary molding is not particularly limited, but an inert gas atmosphere (nitrogen, nitrogen,
Argon, helium) or 10 ⁰ Pa or less under a reduced pressure is preferred.

Subsequently, the magnet powder is pressure-sintered. The pressure sintering method used for sintering the magnet powder while applying pressure is not particularly limited, but it is preferable to apply the hot pressing method or the discharge plasma sintering method. The discharge plasma sintering method is more preferable from the viewpoint of shortening the sintering process. Is not particularly limited and atmosphere at that time, from the viewpoint of preventing oxidation of magnet powder inactive gas atmosphere (nitrogen, argon, helium, etc.) to pressure sintering under vacuum or 10 ⁰ Pa or less preferred. However, in the discharge plasma sintering method, since the magnet powder is suppressed from being oxidized by the cleaning action of the plasma generated between the powder particles in the initial stage of sintering, the sintering in the air is also possible.

By press-sintering the magnet powder in this manner, dislocations and strains that may occur inside the magnet powder due to pressurization are suppressed, and the crystal grain size of the magnet is maintained while the magnet is densified. Is possible. However, if the pressing force applied to the magnet powder is too large, dislocations and strains may remain inside the magnet powder, and if the pressing force is too small, the densification may not proceed sufficiently and the density of the magnet may decrease. is there. On the other hand, if the sintering temperature is too high, the crystal grain size may increase and the coercive force of the magnet may decrease. If the sintering temperature is too low, densification may not proceed sufficiently and the magnet density may decrease. . Therefore, in pressure sintering, it is preferable to select the optimum combination of the pressing force and the sintering temperature in consideration of these adverse effects. This makes it possible to manufacture a dense bulk magnet with suppressed damage to the magnet powder.

Specifically, when the sintering temperature is x (° C.) and the applied pressure is y (tonf / cm ² ), the sintering temperature is 5
If 00 ≦ x <650, then 3.1 ≦ y ≦
It is preferable to control the pressure sintering conditions so that the pressure becomes 6.0. Further, when the sintering temperature is in the range of 650 ≦ x ≦ 800, −0.02x + 16.1 ≦ y ≦ −0.0.
It is preferable to control the pressure sintering conditions so that the pressure is 2x + 19. Further, when the sintering temperature is in the range of 800 <x ≦ 900, it is preferable to control the pressure sintering condition so that 0.1 ≦ y ≦ 3.0. Either or both of the sintering temperature and the pressing force may be varied within the range satisfying these conditions. The term "sintering temperature" as used herein means the maximum ambient temperature around the magnet powder in the pressure sintering process, and is usually measured by a sensor or the like provided inside the pressure sintering device.

The temperature rising rate during pressure sintering is not particularly limited, but if it is less than 10 K / min, grain growth is likely to occur and the magnet characteristics may be deteriorated. On the other hand, if it exceeds 50 K / min, the temperature distribution in the mold may become non-uniform.
From the above, the temperature rising rate of pressure sintering is set to 10 to 50 K / mi.
It is preferably n.

If the holding time during pressure sintering is too long, crystal grain growth may be promoted and the magnet characteristics may deteriorate. Therefore, the holding time is preferably short, specifically 0 to 5 minutes. The holding time means the time of holding at the sintering temperature. For example, from 25 ℃ to 25K
Suppose that the temperature is increased to 525 ° C. at a heating speed of −1 min / min and the temperature lowering process is started immediately after reaching 525 ° C. The sintering temperature is 525 ° C. and the holding time is 0 min.

The release of the pressing force in the temperature lowering process after heating to the sintering temperature is not particularly limited either, but from the viewpoint of securing the density of the magnet and preventing the magnet from cracking and being applied, it is 5
It is desirable to release the applied pressure at about 00 ° C or less.

The rare earth-containing bulk magnet manufactured by the manufacturing method of the present invention has higher magnet characteristics than conventional magnets. Therefore, when this bulk magnet is applied to a motor, a magnetic field sensor, a rotation sensor, an acceleration sensor, a torque sensor, etc., it promotes downsizing and weight reduction of the product. Contribute to improvement.

The thickness of the rare earth-containing bulk magnet produced by the production method of the present invention is not particularly limited,
It is preferable to adjust appropriately according to the application. Further, the shape of the rare earth-containing bulk magnet is also preferably adjusted appropriately according to the application, and is not particularly limited.

Various means for improving the properties of the obtained bulk magnet may be adopted. For example, a protective film may be provided on the surface of the rare earth-containing bulk magnet in order to protect the rare earth magnet that is easily oxidized. The structure of the protective film is not particularly limited, and a suitable composition may be selected according to the magnet characteristics, and the thickness may be determined so that a sufficient protective effect can be obtained. As a specific example of the protective film, a metal film (T
Examples thereof include i, Ta, Ca, Mo, Ni, Zn, etc., inorganic compound films (TiN, FeN, CrN, NiO, FeO, etc.), and organic compound films (epoxy resin, phenol resin, polyurethane, polyester, etc.).

Various known techniques can be appropriately applied to the processing of the rare earth-containing bulk magnet. That is, grinding (outer surface grinding,
Processing such as inner surface grinding, surface grinding, molding grinding), cutting (outer circumference cutting, inner circumference cutting), lapping, chamfering, etc. can be performed. As the processing tool, a diamond, a GC grindstone, an outer / inner peripheral cutting machine, an outer / inner peripheral grinding machine, a surface grinder, an NC lathe, a milling machine, a machining center or the like can be used.

[0040]

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

<1. Investigation of relationship between applied pressure and sintering temperature and magnet characteristics of bulk magnet> As a magnet powder, particle size was 42
Commercially available Ne-Fe-B system anisotropic H classified to 5 μm or less
DDR magnet powder (coercive force HcJ = 11.8 kOe, powder density D = 7.7 g / cm ³ , average particle diameter 200 μm, rare earth content 12.6 atom%) was prepared. This is filled in a non-magnetic WC type, and a pressure of 2 is applied in a magnetic field of 25 kOe.
Temporary molding was performed under a pressure of tonf / cm ² .

Then, a rare earth-containing bulk magnet was produced by pressure sintering using a discharge plasma sintering apparatus. The conditions of pressure sintering (pressure, sintering temperature) are as shown in Table 1. The pressure sintering holding time was 0 min, and the temperature rising rate was 20 to 25 K / min. The pressure was released at 500 ° C. when the temperature was lowered. Table 1 shows the coercive force (HcJ) and density of the obtained rare earth-containing bulk magnet.

Based on the results in Table 1, the horizontal axis represents the sintering temperature and the vertical axis represents the pressing force (FIG. 1). Figure 1
, The black circles have a coercive force HcJ of 11.5 kOe or more,
In addition, a rare earth-containing bulk magnet satisfying a magnet density of 7.65 g / cm ³ or more is shown. On the other hand, white circles indicate rare earth-containing bulk magnets that do not satisfy at least one of the above conditions with respect to coercive force and magnet density. As shown in FIG. 1, by controlling the conditions of the pressing force and the sintering temperature, it is possible to obtain a rare earth-containing bulk magnet that is densified to near the true density and does not cause deterioration in coercive force. Was done. By the way, in the range surrounded by the polygons shown by the thick lines in FIG. 1, the sintering temperature is x (° C.) and the applied pressure is y.
(Tonf / cm ² ), in the range of 500 ≦ x <650, 3.1 ≦ y ≦ 6.0, 650 ≦ x ≦ 800
In the range of −0.02x + 16.1 ≦ y ≦ −0.0
0.1 in the range of 2x + 19, 800 <x ≦ 900
≦ y ≦ 3.0.

[0044]

[Table 1]

<2. Rare earth element content in magnet powder and bar
Investigation of relationship with magnet characteristics of Luk magnet> As magnet powder, particles
Includes a certain amount of neodymium classified to a diameter of 425 μm or less
Commercially available Ne-Fe-B system anisotropic HDDR magnet powder (powder
Density D = 7.7 g / cm ³, Average particle size 200 μm)
Got ready. This was filled in a non-magnetic WC type, and 25 kOe
Applied pressure 2tonf / cm in magnetic field²Temporary molding with the pressing force of
did.

Thereafter, a rare earth-containing bulk magnet was produced by pressure sintering using a discharge plasma sintering device. The applied pressure is 4 tonf / cm ² , and the sintering temperature is 70
It was set to 0 ° C. The holding time of pressure sintering was 0 min, and the temperature rising rate was 20 to 25 K / min. To release the pressure,
The temperature was lowered at 500 ° C. Table 2 shows the relationship between the neodymium content in the magnet powder and the magnet coercive force (HcJ), residual magnetic flux density (Br), and density of the obtained rare earth-containing bulk magnet.

[0047]

[Table 2]

As shown in Table 2, it was shown that when the rare earth element content is 11 to 13 atom%, the magnet characteristics of the obtained rare earth element-containing bulk magnet are improved.

<3. Investigation of relationship between average particle size of magnet powder and magnet characteristics of bulk magnet> Commercially available Ne-Fe-B system anisotropic HDDR in which the particle size of the magnet powder is classified into a predetermined range
Magnet powder (coercive force HcJ = 11.8 kOe, powder density D = 7.7 g / cm ³ , rare earth content 12.6 atom)
%) Prepared. Fill this into a non-magnetic WC type, 25k
Temporary molding was performed in a magnetic field of Oe with a pressure of ² tonf / cm ² .

Then, a rare earth-containing bulk magnet was produced by pressure sintering using a discharge plasma sintering apparatus. The applied pressure is 4 tonf / cm ² , and the sintering temperature is 70
It was set to 0 ° C. The holding time of pressure sintering was 0 min, and the temperature rising rate was 20 to 25 K / min. To release the pressure,
The temperature was lowered at 500 ° C. Average particle size of magnet powder and magnet coercive force (Hc) of the obtained rare earth-containing bulk magnet
J), residual magnetic flux density (Br) and relationship with density are shown in Table 3.
Shown in.

[0051]

[Table 3]

As shown in Table 3, it was shown that when the average particle diameter of the magnet powder is 1 to 500 μm, the magnet characteristics of the obtained rare earth-containing bulk magnet are improved.

[Brief description of drawings]

FIG. 1 is a graph obtained by plotting the sintering temperature on the horizontal axis and the pressing force on the vertical axis based on the results of Table 1.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C22C 38/00 303 C22C 38/00 303D (72) Inventor Tetsuro Tayu Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa No. 2 Nissan Motor Co., Ltd. (72) Inventor Munekatsu Shimada No. 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Mako Kano No. 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Nissan Motor Co., Ltd. ( 72) Inventor Toshio Hori 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Nissan Motor Co., Ltd. (72) Inventor Kazuo Asaka 520 Minorita, Matsudo City, Chiba Prefecture (72) Chiyo Ishihara 520 Minorita, Matsudo City, Chiba Prefecture F term (reference) 4K018 AA27 BA18 BB04 EA02 EA22 KA45 KA63 5E040 AA04 BD01 CA01 HB07 NN01 NN12 NN18 5E062 CC05 CD04 CE01 CF02 C G02 CG03

Claims (7)

[Claims] 1. A method for producing a rare earth-containing bulk magnet, which comprises molding Nd—Fe—B anisotropic HDDR magnet powder in a magnetic field at room temperature and then pressure sintering. 2. The method for producing a rare earth-containing bulk magnet according to claim 1, wherein a hot pressing method or a spark plasma sintering method is used as the pressure sintering method. 3. The pressure sintering condition is that the sintering temperature is x.
The rare earth element according to claim 1 or 2, wherein 500 ≤ x <650 and 3.1 ≤ y ≤ 6.0, where (° C) and the applied pressure are y (tonf / cm ² ). Manufacturing method of contained bulk magnet. 4. The pressure sintering condition is that the sintering temperature is x.
(° C.) and the applied pressure is y (tonf / cm ² ), 650 ≦ x ≦ 800 and −0.02x + 16.1 ≦
The method for producing a rare earth-containing bulk magnet according to claim 1, wherein y ≦ −0.02x + 19. 5. The pressure sintering is performed under the condition that the sintering temperature is x.
3. The rare earth according to claim 1, wherein 800 <x ≦ 900 and 0.1 ≦ y ≦ 3.0, where (° C.) and the applied pressure are y (tonf / cm ² ). Manufacturing method of contained bulk magnet. 6. The rare earth element content of the magnet powder is 11 to 13a based on the total amount of elements contained in the magnet powder.
It is tom%, The manufacturing method of the rare earth containing bulk magnet of any one of Claims 1-5 characterized by the above-mentioned. 7. The average particle size of the magnet powder is 1 to 500.
It is μm, Any one of claims 1 to 6, characterized in that
Item 7. A method for producing a rare earth-containing bulk magnet according to item.