JP2006270087A - Method of producing rare-earth sintered magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a rare-earth sintered magnet which increases the strength of a molding and enhances magnetic properties of a sintered magnet obtained finally. <P>SOLUTION: A method of producing a rare-earth sintered magnet comprises a step of pulverizing raw material alloy powder to obtain pulverized powder, a step of applying a magnetic field to the pulverized powder and press-molding the pulverized powder to obtain a molding, and a step of sintering the molding. A lubricant including paraffin and a compound represented by one of the group composed of R<SB>1</SB>-OCO-R<SB>2</SB>, R<SB>1</SB>-OCO-R<SB>3</SB>-OH, R<SB>1</SB>-OH, and (R<SB>1</SB>-COO)<SB>m</SB>M is added to the pulverized powder, and then the molding is formed, where R<SB>1</SB>is C<SB>n</SB>H<SB>2n+1</SB>or C<SB>n</SB>H<SB>2n-1</SB>, R<SB>2</SB>is H or C<SB>n</SB>H<SB>2n+1</SB>, R<SB>3</SB>is C<SB>n</SB>H<SB>2n</SB>, M is a metal, and n and m are an integer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a rare earth sintered magnet typified by an Nd—Fe—B system.

Rare earth sintered magnets (hereinafter simply referred to as sintered magnets) are widely used as high-performance magnets, and the demand for them increases with the miniaturization of various electronic devices and the increase in electronic devices in automobiles. Yes. In general, the higher the degree of orientation of the magnet, the higher the residual magnetic flux density. For this reason, a magnetic field is often applied to the raw material powder during molding, and compression molding is often performed while the raw material powder is oriented (so-called magnetic field molding).
At this time, in order to improve the orientation of the raw material powder with respect to the magnetic field, a lubricant may be added to the raw material powder.
Further, prior to forming in a magnetic field as described above, a lubricant may be added in order to improve pulverizability in the step of pulverizing the raw material alloy with a jet mill or the like to obtain the raw material powder (for example, patent document). 1).

JP-A-8-111308 (Claims)

  By the way, when the kind and addition amount of the lubricant are adjusted in order to obtain high magnetic characteristics, the strength of the molded body is lowered and the yield of the molded body is lowered. On the other hand, if the lubricant is adjusted so as to increase the strength of the compact, it is difficult to improve the magnetic properties of the finally obtained sintered magnet.

  The present invention has been made based on such a technical problem, and an object of the present invention is to provide a method for producing a rare earth sintered magnet having a molded body having high strength and high magnetic properties.

The method for producing a rare earth sintered magnet of the present invention includes a step of pulverizing a raw material alloy powder to obtain a pulverized powder, a step of applying a magnetic field to the pulverized powder and press-molding, and a molded body, A compound A represented by the general formula C _n H _{2n + 2} , R ₁ —OCO—R ₂ , R ₁ —OCO—R ₃ —OH, R ₁ —OH, (R ₁ — COO) Compound B represented by any one of the group consisting of _m M (R ₁ is C _n H _{2n + 1} , or C _n H _2n-1, R ₂ is H or C _n H _{2n + 1,} R _3. Is C _n H _{2n, where} M is a metal, and n and m are integers). At this time, the addition timing of the lubricant may be in the state of the raw material alloy powder before pulverization, but is preferably after the pulverization process of the raw material powder or after the pulverization of the raw material powder. In particular, it is preferable to add the lubricant by introducing the granular lubricant into the pulverizing means together with the raw material alloy powder in the process of pulverizing the raw material alloy powder.

Here, R ₁ of Compound B is preferably C _n H _{2n + 1} (n is 10 or more). Examples of Compound B include stearic acid, glyceryl monostearate, zinc stearate, stearyl alcohol, lauric acid and behen. Examples include at least one compound selected from the group consisting of acids. n is preferably 12 or more and 21 or less, and more preferably 12 or more and 18 or less.

  The particle diameters of Compound A and Compound B are each preferably 800 μm or less.

According to the present invention, from the compound A represented by the general formula C _n H _{2n + 2} , R ₁ —OCO—R ₂ , R ₁ —OCO—R ₃ —OH, R ₁ —OH, (R ₁ —COO) _m M Compound B (R ₁ is C _n H _{2n + 1} , or C _n H _2n-1, R ₂ is H or C _n H _{2n + 1,} R ₃ is C _n H _2n. M is a metal, and n and m are integers) added to the raw material alloy powder and pulverized powder, thereby forming the raw material alloy in the pulverization process and the orientation of the pulverized powder in the magnetic field forming process. It is possible to increase the strength of the body and the magnetic characteristics of the finally obtained sintered magnet.

Hereinafter, the present invention will be described in detail based on embodiments.
The present invention can be applied to, for example, a rare earth sintered magnet, particularly an RTB based sintered magnet.
This RTB-based sintered magnet contains 25 to 37 wt% of a rare earth element (R). Here, R in the present invention has a concept including Y, and therefore 1 of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. It is selected from species or two or more species. If the amount of R is less than 25 wt%, the R ₂ T ₁₄ B phase, which is the main phase of the RTB-based sintered magnet, is not sufficiently generated, and α-Fe having soft magnetism is precipitated and retained. Magnetic force is significantly reduced. On the other hand, when R exceeds 37 wt%, the volume ratio of the R ₂ T ₁₄ B phase, which is the main phase, decreases, and the residual magnetic flux density decreases. Further, R reacts with oxygen, the amount of oxygen contained increases, and accordingly, the R-rich phase effective for the generation of coercive force decreases, leading to a decrease in coercive force. Therefore, the amount of R is set to 25 to 37 wt%. A desirable amount of R is 28 to 35 wt%, and a more desirable amount of R is 29 to 33 wt%.

The RTB-based sintered magnet contains 0.5 to 4.5 wt% of boron (B). When B is less than 0.5 wt%, a high coercive force cannot be obtained. On the other hand, when B exceeds 4.5 wt%, the residual magnetic flux density tends to decrease. Therefore, the upper limit of B is set to 4.5 wt%. A desirable amount of B is 0.5 to 1.5 wt%, and a more desirable amount of B is 0.8 to 1.2 wt%.
This RTB-based sintered magnet contains Co of 2.0 wt% or less (excluding 0), desirably 0.1 to 1.0 wt%, and more desirably 0.3 to 0.7 wt%. can do. Co forms the same phase as Fe, but is effective in improving the Curie temperature and improving the corrosion resistance of the grain boundary phase.

The RTB-based sintered magnet can contain one or two of Al and Cu in the range of 0.02 to 0.5 wt%. By containing one or two of Al and Cu in this range, it is possible to increase the coercive force, the corrosion resistance, and the temperature characteristics of the obtained R-T-B sintered magnet. In the case of adding Al, the desirable amount of Al is 0.03 to 0.3 wt%, and the more desirable amount of Al is 0.05 to 0.25 wt%. Further, in the case of adding Cu, the desirable amount of Cu is 0.15 wt% or less (not including 0), and the more desirable amount of Cu is 0.03 to 0.12 wt%.
Furthermore, this RTB-based sintered magnet allows the inclusion of other elements. For example, elements such as Zr, Ti, Bi, Sn, Ga, Nb, Ta, Si, V, Ag, and Ge can be appropriately contained. On the other hand, it is desirable to reduce impurity elements such as oxygen, nitrogen, and carbon as much as possible. In particular, the amount of oxygen that impairs magnetic properties is preferably 5000 ppm or less, more preferably 3000 ppm or less. This is because when the amount of oxygen is large, the rare-earth oxide phase, which is a nonmagnetic component, increases and the magnetic properties are deteriorated.

The present invention is not limited to the R-T-B based sintered magnet as described above, but can be applied to other rare earth sintered magnets. For example, the present invention can be applied to an R—Co based sintered magnet.
The R—Co based sintered magnet contains R, one or more elements selected from Fe, Ni, Mn, and Cr, and Co. In this case, it preferably further contains at least one element selected from Cu or Nb, Zr, Ta, Hf, Ti and V, and particularly preferably from Cu and Nb, Zr, Ta, Hf, Ti and V. Containing one or more selected elements. Among these, an intermetallic compound of Sm and Co, preferably an Sm ₂ Co ₁₇ intermetallic compound, is the main phase, and a subphase mainly composed of SmCo ₅ is present at the grain boundary. The specific composition may be appropriately selected according to the production method, required magnetic characteristics, and the like. For example, R: 20 to 30 wt%, particularly about 22 to 28 wt%, Fe, Ni, Mn, and Cr Above: about 1 to 35 wt%, one or more of Nb, Zr, Ta, Hf, Ti and V: 0 to 6 wt%, especially about 0.5 to 4 wt%, Cu: 0 to 10 wt%, especially 1 to 10 wt% To the extent, Co: the balance composition is desirable.
The R-T-B sintered magnet and the R-Co sintered magnet have been described above, but the present invention does not prevent application to other rare earth sintered magnets.

Hereinafter, a method for producing a rare earth sintered magnet according to the present invention will be described in the order of steps.
The raw material alloy can be produced by a strip casting method or other known melting methods in a vacuum or an inert gas, preferably an argon atmosphere. In the strip casting method, a molten metal obtained by melting a raw material metal in a non-oxidizing atmosphere such as an argon gas atmosphere is jetted onto the surface of a rotating roll. The melt rapidly cooled by the roll is rapidly solidified in the form of a thin plate or flakes (scales). This rapidly solidified alloy has a homogeneous structure with a crystal grain size of 1 to 50 μm. The raw material alloy can be obtained not only by the strip casting method but also by a melting method such as high frequency induction melting. In order to prevent segregation after dissolution, for example, it can be solidified by pouring into a water-cooled copper plate. An alloy obtained by the reduction diffusion method can also be used as a raw material alloy.
When obtaining an RTB-based sintered magnet, a so-called alloy using a R ₂ T ₁₄ B crystal grain (low R alloy) and an alloy containing more R than a low R alloy (high R alloy) is used. A mixing method can also be applied to the present invention.

The raw material alloy is subjected to a grinding process. In the case of the mixing method, the low R alloy and the high R alloy are pulverized separately or together. The pulverization process includes a coarse pulverization process and a fine pulverization process.
First, in the coarse pulverization step, the raw material alloy is coarsely pulverized to a particle size of about several hundred μm to obtain a coarsely pulverized powder (raw material alloy powder). The coarse pulverization is desirably performed in an inert gas atmosphere using a stamp mill, a jaw crusher, a brown mill or the like. Prior to coarse pulverization, it is effective to perform pulverization by allowing hydrogen to be stored in the raw material alloy and then releasing it. The hydrogen releasing treatment is performed for the purpose of reducing hydrogen as an impurity as a rare earth sintered magnet.

  After the coarse pulverization process, the process proceeds to the fine pulverization process. A jet mill is mainly used for fine pulverization. By pulverizing the coarsely pulverized powder, the average particle size is preferably 2.5 to 6 μm. More preferably, a finely pulverized powder (ground powder) of 3 to 5 μm is obtained in order to increase the height. The jet mill releases a high-pressure inert gas from a narrow nozzle to generate a high-speed gas flow, accelerates the coarsely pulverized powder with this high-speed gas flow, collides with the coarsely pulverized powder, and collides with the target or container wall. It is a method of generating a collision and crushing.

  At this time, a lubricant is added to the raw material alloy powder in the fine grinding step. Lubricating and orientation during molding can be improved by adding a lubricant. The lubricant is preferably added to the raw material alloy powder before the start of the fine pulverization process. However, the lubricant may be added during the fine pulverization process or after the fine pulverization process and before the granule preparation process or in the magnetic field. It may be added to the finely pulverized powder before the molding step.

The lubricant is a group consisting of the compound A represented by the general formula C _n H _{2n + 2} , R ₁ —OCO—R ₂ , R ₁ —OCO—R ₃ —OH, R ₁ —OH, (R ₁ —COO) _m M. Compound B (R ₁ is C _n H _{2n + 1} , or C _n H _2n-1, R ₂ is H or C _n H _{2n + 1,} R ₃ is C _n H _2n. M Is a metal, and n and m are integers.
As the compound A, a commonly used paraffin wax can be used without particular limitation, and a linear hydrocarbon (normal paraffin) is preferable, but a branched hydrocarbon (isoparaffin) or a cyclic hydrocarbon (cycloparaffin) is preferable. May be. Preferred metals for M are, for example, Zn, Al, Cu, Ca, Na, and Mg.

The compound B contained in the lubricant is, for example, a fatty acid compound or an alcohol, and specifically includes higher fatty acids having 10 or more carbon atoms, higher fatty acid esters, higher fatty acid metal salts, higher alcohols, and the like. Among these, the compound B is preferably a compound in which R ₁ is a hydrocarbon having 17 and 18 carbon atoms. Specific examples include lauric acid (C ₁₂ H ₂₅ —COOH), behenic acid (C ₂₁ H ₄₃ —COOH), stearate _{(C 17} H 35 -COOH), glyceryl monostearate _{(C 17 H 35 -COO-C} 3 H 6 -OH), zinc stearate ^{_{((C 17 H 35 -COO)}} - 2 Zn 2+) and stearyl it can be mentioned alcohols _{(C 18 H 37 -O-H} ). Of these, stearic acid is preferred. As the compound having this R ₁ —O— group, only one kind of compound may be used, but a plurality of compounds may be used.

The lubricant is preferably added in the form of granules. In that case, the lubricant is added by introducing a granular lubricant into a jet mill for pulverizing the raw material alloy powder.
The particle diameter of the lubricant is preferably 10 to 1000 μm, more preferably 10 to 800 μm, and particularly preferably 20 to 500 μm in order to increase the strength of the molded body described later and to increase the magnetic properties of the sintered magnet. In order to make the lubricant have the above particle diameter, it is preferable to grind the lubricant and classify it with a sieve or the like. In order to pulverize the lubricant, it is preferable that the lubricant is frozen using, for example, liquid nitrogen, and pulverized in that state with a pulverization mill or the like.

  The addition amount of the lubricant is preferably as much as possible from the viewpoint of improving the grindability, but is preferably as small as possible from the viewpoint of the magnetic properties and the strength of the molded body. The addition amount of the lubricant needs to be appropriately set according to the types of the compound A and the compound B and the mixing ratio thereof, but if the total amount is set within a range of 0.01 to 1.0 wt%. Good. In order to increase the strength of the compact and increase the magnetic properties of the sintered magnet, it is preferably 0.05 to 0.15 wt%, more preferably 0.05 to 0.1 wt%. Note that the addition of the lubricant within the range recommended by the present invention does not adversely affect the coercive force (HcJ).

  In the case of the mixing method, the timing of mixing the two kinds of alloys is not limited. However, when the low R alloy and the high R alloy are separately pulverized in the pulverization step, the pulverized low R alloy powder is used. And high R alloy powder in a nitrogen atmosphere. The mixing ratio of the low R alloy powder and the high R alloy powder may be about 80:20 to 97: 3 by weight. The mixing ratio when the low R alloy and the high R alloy are pulverized together is the same.

The granular granulated powder obtained as described above (or finely pulverized powder when the granule preparation step is omitted) is filled in a mold cavity and subjected to molding in a magnetic field.
The molding pressure in the magnetic field molding may be in the range of 0.3 to 3 ton / cm ² (30 to 300 MPa). The molding pressure may be constant from the start to the end of molding, may increase or decrease gradually, or may vary irregularly. The lower the molding pressure is, the better the orientation is. However, if the molding pressure is too low, the strength of the molded body is insufficient and handling problems occur. Therefore, the molding pressure is selected from the above range in consideration of this point. The final relative density of the molded body obtained by molding in a magnetic field is usually 50 to 60%.
The applied magnetic field may be about 12 to 20 kOe (960 to 1600 kA / m). Further, the applied magnetic field is not limited to a static magnetic field, and may be a pulsed magnetic field. A static magnetic field and a pulsed magnetic field can also be used in combination.

  The molded body obtained by molding in a magnetic field is subjected to binder removal processing. This is to prevent a decrease in magnetic properties due to carbon residue. The binder removal treatment is preferably performed under a predetermined heat treatment condition in a hydrogen atmosphere.

  After the binder removal treatment, the compact is sintered in a vacuum or an inert gas atmosphere. Although it is necessary to adjust sintering temperature by various conditions, such as a composition, a grinding | pulverization method, a difference of an average particle diameter, and a particle size distribution, what is necessary is just to sinter at 1000-1200 degreeC for about 1 to 10 hours in a vacuum.

  Now, after sintering, the obtained sintered body can be subjected to an aging treatment. This process is an important process for controlling the coercive force. When the aging treatment is performed in two stages, holding for a predetermined time at 750 to 950 ° C. and 500 to 700 ° C. is effective. When the heat treatment in the vicinity of 800 ° C. is performed after sintering, the coercive force increases, which is particularly effective in the mixing method. In addition, since the coercive force is greatly increased by heat treatment near 600 ° C., when aging treatment is performed in one stage, it is preferable to perform aging treatment near 600 ° C.

<Manufacture of rare earth sintered magnets>
First, the molded object used as evaluation object and the rare earth sintered magnet which sintered this were produced. The composition of the raw material alloy was Nd 24.5 wt%, Pr 6.0 wt%, Dy 1.8 wt%, Co 0.5 wt%, Al 0.2 wt%, Cu 0.07 wt%, B 1.0 wt%, and the balance Fe. The raw material metal or alloy was blended so as to have the above composition, and the raw material alloy thin plate was melted and cast by a strip casting method.

  The obtained raw material alloy thin plate is hydrogen pulverized and then mechanically coarsely pulverized by a brown mill to obtain raw material alloy coarse powder. As a lubricant (grinding aid), 0.05% by weight of each of Compound A and Compound B shown in Table 1 was added to the raw material alloy coarse powder. The average particle size of Compound A and Compound B is about 300 μm. Next, the mixture was finely pulverized in a high-pressure nitrogen gas atmosphere using an airflow pulverizer (jet mill) to obtain an average particle diameter D50 = 4.1 μm to obtain a rare earth alloy powder.

  The obtained powder was molded in a magnetic field to obtain a molded body having a predetermined shape. In molding in a magnetic field, the powder was molded at a molding pressure of 147 MPa in a magnetic field of 1200 kA / m. The magnetic field direction is a direction perpendicular to the pressing direction. Two types of dimensions, 20 mm × 18 mm × 6.5 mm and 20 mm × 18 mm × 13 mm, were obtained for the molded body. And the bending strength was measured with the following method as the intensity | strength of a molded object using the former molded object.

  The bending strength measurement was performed according to Japanese Industrial Standard JIS R 1601. Specifically, as shown in FIG. 1, a molded body 11 having a shape of 20 mm × 18 mm × 6.5 mm is placed on two round bar-shaped supports 12 and 13, and a central position on the molded body 11 is placed. A round bar-shaped support 14 was placed on and a load was applied. The direction in which the bending pressure was applied was the pressing direction. The radii of the round bar-shaped supports 12, 13, and 14 were 3 mm, the distance between fulcrums was 10 mm, and the load point moving speed was 0.5 mm / min. The longitudinal direction of the molded body 11 and the support 14 were arranged so as to be parallel to each other. The number of samples was 10.

  Further, magnetic properties were evaluated using a molded body having a shape of 20 mm × 18 mm × 13 mm as an evaluation sample. This molded body was sintered at 1030 ° C. for 4 hours, and then subjected to aging treatment at 900 ° C. for 1 hour and 530 ° C. for 1 hour. The surface of the obtained sintered body was ground to obtain a rectangular parallelepiped sample. This sample was evaluated for magnetic properties using a BH tracer.

Further, as a comparative example, a sample was prepared in the same manner as in Example 1 except that only 0.1% by weight of compound B shown in Table 1 was added without adding compound A, and a compact and a sintered magnet were obtained. And magnetic properties were evaluated.
The results of Examples and Comparative Examples are shown in Table 1.

As shown in Table 1, in the comparative example, Br exceeded 13.2 kG, but the strength of the compact was below 0.9 MPa.
On the other hand, when compound A and compound B shown in Table 1 are added in combination, Br exceeds 13.2 kG, and the compact strength exceeds 1.05 MPa, and can have both high compact strength and high magnetic properties. Was confirmed. In addition, it was found that the obtained magnetic properties were equivalent to the magnetic properties in the comparative example, and it was confirmed that the strength of the molded product can be increased without significantly reducing the magnetic properties by adding Compound A. It was done. In particular, when lauric acid (n = 12) is used as compound B, Br is as high as 13.33 kG, and when behenic acid (n = 21) is used as compound B, the compact strength is 1.21 MPa. It is noted that
Thus, by adding a lubricant to the raw material alloy in the fine pulverization step, the strength of the compact is high while ensuring the pulverization property of the raw material alloy in the pulverization step and the orientation of the pulverized powder in the forming step in the magnetic field, Furthermore, the sintered magnet finally obtained has a high magnetic property.

  As a lubricant, a sample was prepared in the same manner as in Example 1 except that the mixing ratio of paraffin of compound A and stearic acid of compound B was changed to the ratio shown in Table 2, and a molded body and a sintered magnet were obtained. And magnetic properties were evaluated. The results are shown in Table 2. As in Example 1, the total amount of compound A paraffin and compound B stearic acid was 0.1 wt%.

  As shown in Table 2, when the mixing ratio of Compound B exceeds 75%, the compact strength is less than 1.05 MPa. On the other hand, when the mixing ratio of Compound A is 100%, Br is less than 13.20 kG. Therefore, when paraffin is used as compound A and stearic acid is used as compound B, the mixing ratio of compound A and compound B is preferably set to be 1: 3 to 9: 1 on a weight basis. Moreover, since the high Br of 13.25 kG or more and the molded object strength of 1.05 MPa or more can be combined, the more preferable range of the mixing ratio of Compound A and Compound B is 1: 3 to 3: 1.

  As a lubricant, a sample was prepared in the same manner as in Example 1 except that the total addition amount of paraffin of compound A and stearic acid of compound B was set as shown in Table 3, and a compact and a sintered magnet were obtained. The strength and magnetic properties were evaluated. The results are shown in Table 3. As in Example 1, the mixing ratio of the paraffin of compound A and the stearic acid of compound B was 1: 1.

As shown in Table 3, Br increases as the additive amount of the lubricant increases, but the strength of the compact gradually decreases. When the addition amount of the lubricant is in the range of 0.05 to 0.1 wt%, Br is 13.2 kG or more and the compact strength is 1.17 MPa or more. Therefore, when compound A and compound B are mixed at approximately 1: 1, the total amount of lubricant added is preferably 0.05 to 0.15 wt%, more preferably 0.05 to 0.1 wt%. It can be said.
In addition, as a result of measuring the coercive force (HcJ) for the sample with the lubricant addition amount of 0.025 wt% and the sample with the lubricant addition amount of 0.10 wt%, as shown below, both showed equivalent HcJ. Indicated. Considering that the amount of addition of the latter lubricant is four times that of the former, it is confirmed that the addition of the lubricant recommended by the present invention within the range recommended by the present invention has no adverse effect on HcJ. did it.
Sample with lubricant addition amount of 0.025 wt%: HcJ 18.5 Oe
Sample with lubricant addition amount of 0.10 wt%: HcJ 18.7 Oe

  As a lubricant, a sample was prepared in the same manner as in Example 1 except that the particle diameters of the paraffin of Compound A and the stearic acid of Compound B are shown in Table 4, and a molded body and a sintered magnet were obtained. And magnetic properties were evaluated. The results are shown in Table 4. As in Example 1, the mixing ratio of paraffin of compound A and stearic acid of compound B was 1: 1, and the total amount of lubricant added was 0.1 wt%.

  As shown in Table 4, since the Br is less than 13.2 kG when the particle size of the lubricant exceeds 1000 μm, the average particle size of the lubricant is preferably 1000 μm or less. Since Br improves as the particle size (average particle size) of the lubricant decreases, the average particle size of the lubricant is preferably 800 μm or less, and more preferably 20 to 500 μm. When the average particle size of the lubricant is in the range of 20 to 500 μm, it is possible to have both a Br of 13.2 kG or more and a molded body strength of 1.10 MPa or more.

It is a figure explaining the bending strength measuring method according to Japanese Industrial Standards JISR1601.

Claims (4)

Pulverizing raw material alloy powder to obtain pulverized powder;
Any one of the group consisting of the compound A represented by the general formula C _n H _{2n + 2} and R ₁ —OCO—R ₂ , R ₁ —OCO—R ₃ —OH, R ₁ —OH, (R ₁ —COO) _m M Compound B (R ₁ is C _n H _{2n + 1} , or C _n H _2n-1, R ₂ is H or C _n H _{2n + 1,} R ₃ is C _n H _2n, M is a metal, n , M is an integer.) A step of applying a magnetic field to the pulverized powder to which is added, and obtaining a molded body by pressure molding;
And a step of sintering the compact. A method for producing a rare earth sintered magnet. The method for producing a rare earth sintered magnet according to claim 1, wherein the R ₁ of the compound B is C _n H _{2n + 1} (n is 10 or more).   3. The rare earth firing according to claim 2, wherein the compound B is at least one compound selected from the group consisting of stearic acid, glyceryl monostearate, zinc stearate, stearyl alcohol, lauric acid and behenic acid. A manufacturing method of a magnet.   4. The method for producing a rare earth sintered magnet according to claim 1, wherein an average particle size of the compound A and the compound B is 800 μm or less. 5.

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