JP3254229B2 - Manufacturing method of rare earth permanent magnet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rare earth permanent magnet having excellent magnetic properties and used for various electric and electronic devices.

[0002]

2. Description of the Related Art Among rare earth magnets, Nd-Fe-B magnets are:
In recent years, Nd, which is a main component, is abundant in resources, low in cost, and excellent in magnetic properties, and thus its use has been expanding in recent years. Research and development for improving magnetic properties has been energetically conducted since the invention of the Nd-based magnet, and many studies and inventions have been proposed. There are many methods for manufacturing high-performance Nd magnets by mixing and sintering two types of alloy powders having different compositions, which is one of the methods for manufacturing Nd-based sintered magnets (hereinafter referred to as the two-alloy method). Inventions have been proposed.

The two alloy methods proposed so far can be roughly classified into three types. In the first method, one of the raw material alloy powders to be mixed is made into an amorphous or microcrystalline alloy by a liquid quenching method, and a normal rare earth alloy powder is mixed therewith, or both raw material alloy powders are mixed together. A method of producing and mixing by a liquid quenching method [JP-A-63-9
3841, JP-A-63-115307, JP-A-63-252403, JP-A-63-278
208, JP-A-1-108707, JP-A-1-46310, JP-A-1-146309,
Japanese Patent Application Laid-Open No. 1-155603]. Recently, a 50MG alloy using this liquid quenching alloy has been
Reported that magnetic properties exceeding Oe were obtained [E. Otuki, T. Otuka
and T.Imai; 11th.Int.Workshopon Rare Earth Magnet
s, Pittsburgh, Pennsylvania, USA, October (1990), p. 328
See].

A second method is to prepare an alloy in which the two kinds of raw material alloy powders to be mixed are changed mainly as R ₂ Fe ₁₄ B compounds and the kinds and contents of the rare earth elements contained therein are mixed and sintered. Is the way. That is, a method of mixing two kinds of alloys in which the amount ratio of the contained Nd-rich phase or the kind of the rare earth element is changed [Japanese Patent Application Laid-Open Nos. 61-81603, 61-81604 and 61-816]
05, JP-A-61-81606, JP-A-61-81607, JP-A-61-11900
7, JP 61-207546, JP 63-245 90 3, Hei 1-177335 is the JP reference.

The third method is to use one of the alloys mainly as R ₂
A method of producing an Nd-based rare earth magnet by mixing and sintering powders of various low-melting elements, low-melting alloys, rare-earth alloys, carbides, borides, hydrides and the like into an alloy powder composed of an Fe ₁₄ B compound [ JP-A-60-230959, JP-A-61-263201, JP-A-62-1
81402, JP-A-62-182249, JP-A-62-206802, JP-A-62-270
746, JP-A-63-6808, JP-A-63-104406, JP-A-63-114939,
JP-A-63-272006, JP-A-1-111843, and JP-A-1-146308.

[0006]

There are many points that the two-alloy method according to the prior art is not suitable or insufficient for realizing the truly excellent magnetic properties of Nd-based magnet alloys. That is, in the first method described above, the energy product of the magnet alloy is high, but the coercive force is about 9 kOe, and the coercive force decreases with increasing temperature. Magnet properties. The biggest problem is the magnetic field orientation. In the first method, an alloy exhibiting magnetism at room temperature can be obtained by appropriately selecting the composition. However, since the alloy obtained by the liquid quenching method becomes an amorphous amorphous phase or a fine crystal, the alloy is formed into a fine powder and a magnetic field. A specific crystal orientation cannot be oriented in the direction of the magnetic field even if it is oriented in a magnetic field. Therefore, the orientation of the molded body obtained even when the mixed raw material alloy powder is molded in a magnetic field is poor,
After sintering, sufficient magnet properties cannot be obtained.

In the second method, R ₂ in the magnet alloy is
The phase coexisting with the Fe ₁₄ B compound is an Nd-rich phase or Nd _{1 + X} F
e ₄ B ₄ phase, and both phases do not show magnetism at room temperature. Therefore, the presence of a compound having no magnetism disturbs the orientation, and a magnet having excellent magnetic properties cannot be obtained.
Also, in the third method using various elements and various compounds as powders to be mixed, since these compounds do not have magnetism, the demagnetizing field increases during orientation in a magnetic field, and the effective magnetic field strength decreases. Therefore, the rotation of the magnetic particles in the direction of the magnetic field becomes insufficient, and the orientation is disturbed.

In the third method, there is a proposal to improve the magnetic properties by using a low melting point element or alloy in the powder to be mixed. This is based on the idea that nucleation sites such as lattice defects and oxide phases existing at the grain boundaries of the R ₂ Fe ₁₄ B compound are removed and the grain boundaries are cleaned to improve the coercive force. However, the presence of the low melting point phase is actually a disadvantageous condition for improving the magnetic properties for the following reasons. If the low-melting phase is melted from, for example, around 660 ° C., the viscosity of the low-melting phase becomes considerably small at an actual sintering temperature of 1,100 ° C. As a result, the compact shrinks due to liquid phase sintering, and at the same time, the viscosity of the melt surrounding the grains is low, so that the rotation of the magnetic particles easily occurs, the orientation is disturbed, and the magnetic properties deteriorate. In other words, a desirable liquid phase component in the liquid phase sintering of the Nd magnet needs to maintain an appropriate viscosity without disturbing the orientation of the particles, and also to densify the compact and sufficiently clean up the grain boundaries. In the conventional two-alloy method, the roles of the magnetic field orientation and the coercive force improvement involving the liquid phase component are both sufficiently taken into consideration, and the magnetism and melting point of the liquid phase alloy component are appropriately adjusted so that these become the optimum conditions. I didn't adjust it. An object of the present invention is to improve the above-mentioned drawbacks of the two-alloy method and to provide a method for producing a rare-earth permanent magnet having excellent balanced magnetic properties.

[0009]

Means for Solving the Problems In order to solve the above problems, the present inventors have basically reviewed the two-alloy method, and it is sufficient to properly select and combine the types and characteristics of the constituent phases of the magnetic material. The present inventors have found that satisfactory and well-balanced magnetic properties can be obtained, and have studied the manufacturing conditions in detail to complete the present invention. The gist of the present invention is that A alloy is mainly composed of R ₂ T ₁₄
An alloy composed of a B phase (where R represents at least one or more rare earth elements mainly composed of Nd, Pr, and Dy, and T represents Fe or Fe and Co), and the B alloy is composed of R, Co,
Fe, B, M (where R is the same as above, M is Al, C
u, Zn, In, Si, P, S, Ti, V, Cr, M
n, Ge, Zr, Nb, Mo, Pd, Ag, Cd, S
n, Sb, Hf, Ta, or W, representing one or more elements selected from the group consisting of 20 <R ≦ 40;
0.1 ≦ Fe ≦ 55, 15 ≦ Co ≦ 80, 0.1 ≦ B ≦
20, 0.1 and the composition range of ≦ M ≦ 20 (both atomic%), and, R ₂ T ¹ ₁₄ L-phase and / or the R-rich phase as a phase in the B alloy (here R is as defined above , T ¹ is C
transition metals consisting of o or Co and Fe, the transition metal and M (where M is the same), L represents B, B and M a (where M is the same)) and RT ² ₄ L
Phase, RT ² _3-phase, RT ² _2-phase, R ₂ T ² ₇ phase and RT ² ₅ phase (wherein R and L are as defined above, T ² is Co or C
a transition metal consisting of o and Fe, the same transition metal and B,
One or more of the five phases of the same transition metal and M (where M is the same as above), the same transition metal and B and M (where M is the same as above) And at least one of the one or more phases has a melting point of 700 ° C. or more and 1,155 ° C. or less as a mixed phase, and the A alloy powder is 99 to 70% by weight. %
B alloy powder is mixed at a ratio of 1 to 30% by weight with respect to
A method for producing a rare-earth permanent magnet, comprising subjecting the mixed alloy powder to pressure molding in a magnetic field, sintering the compact in a vacuum or an inert gas atmosphere, and further performing aging heat treatment at a low temperature equal to or lower than the sintering temperature. , and the more particularly, RT ² ₄ L phase contained in the B alloy, RT ² _3-phase, RT ² _2-phase, of the five constituent phase of R ₂ T ² ₇ phase and RT ² ₅ phases, at least At least one phase is a magnetic material having a Curie temperature of room temperature or higher;
Moreover, RT ² ₄ L phase contained in the B alloy, RT ² _3-phase, RT
² _two-phase, of the five constituent phase of R ₂ T ² ₇ phase and RT ² ₅ phase, that at least one or more phases of a magnetic material having a Curie temperature and crystal magnetic anisotropy of more than room temperature This is a method for producing a rare earth permanent magnet. further,
The average particle size of the A alloy, the B alloy, and the AB mixed alloy powder is in a range of 0.5 to 20 μm.

Hereinafter, the present invention will be described in detail. The present invention relates to a rare-earth permanent magnet (hereinafter referred to as a magnet alloy C) called a so-called two-alloy method.
A) as a raw material is mainly composed of an R ₂ T ₁₄ B compound phase, and R is Y containing La, Ce, P
It is at least one or more rare earth elements mainly composed of Nd, Pr, and Dy selected from r, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. T represents Fe or Fe and Co,
The Co content is 0.1 to 40% by weight. The addition of Co increases the Curie temperature of the A alloy and also improves the corrosion resistance of the alloy. The alloy A is prepared by melting a raw metal in a vacuum or an inert gas, preferably an Ar atmosphere. As a raw material metal, a pure rare earth element or a rare earth alloy, pure iron, ferroboron, or an alloy thereof is used, but a trace impurity inevitable in general industrial production is included. In the obtained ingot, since the R ₂ T ₁₄ B phase is formed by the peritectic reaction between αFe and the rare earth rich phase, the αFe phase, the R rich phase, the B rich phase, the Nd ₃ Co phase, etc. are also solidified and segregated after casting. May remain. In the present invention, since it is desirable that the R ₂ Fe ₁₄ B phase in the A alloy is large,
Solution treatment is performed as necessary. The condition is vacuum or
In an Ar atmosphere, heat treatment may be performed in a temperature range of 700 to 1,200 ° C. for 1 hour or more.

[0011] B alloy mainly R, Co, Fe, an alloy consisting of B and M, the composition formula _{R a Fe b Co c B d} M e,
Here, R is La, Ce, Pr, Nd, Pm, including Y.
Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b and Lu, at least one or more rare earth elements mainly composed of Nd, Pr and Dy, M is Al, C
u, Zn, In, Si, P, S, Ti, V, Cr, M
n, Ge, Zr, Nb, Mo, Pd, Ag, Cd, S
represents one or more elements selected from n, Sb, Hf, Ta and W. The subscripts a, b, c, d, and e are in the range of 20 <a ≦ 40, 0.1 ≦ b ≦ 55, and 15 ≦ c ≦ 8.
0, 0.1 ≦ d ≦ 20, 0.1 ≦ e ≦ 20, a + b + c + d +
e = 100 (each atomic%), and the raw material metal is melted and cast in a vacuum or an inert gas, preferably an Ar atmosphere like the A alloy. As the raw material metal, a pure rare earth element or a rare earth alloy, pure iron, pure cobalt, ferroboron, various pure metals, and furthermore, an alloy of these are used.
Trace impurities inevitable in general industrial production shall be included. When the amount a of the rare earth element R is less than 20 atomic%, the amount of R is too small, so that a sufficient amount of liquid phase cannot be obtained in the sintering step, and the density of the sintered body does not increase. The melting point is so low that the effect of improving the magnetic properties is lost. Co amount c is ^RT _{2 4} B-phase is less than 15 atomic%, ^RT _{2 3-phase,} ^RT _{2 2 phase,} and the appearance of each phase of R ^{₂ T 2} ₇ phase and ^RT _{2 5} equality is unstable magnetic properties Is not sufficiently obtained. Fe ・ B ・ M
Is an essential component together with Co in order for the desired intermetallic compound to appear as an equilibrium phase in the B alloy, and Fe.B
-Regarding M, the range shown above is a preferable composition range. Further, a B alloy can be produced by heat-treating a ribbon obtained by the liquid quenching method. That is, in the liquid quenching method, the B alloy after quenching is in an amorphous phase or a fine crystalline phase. By heating this at a temperature higher than the crystallization temperature for a certain period of time, crystallization or recrystallization growth is performed. Thus, the predetermined constituent phase of the present invention can be precipitated.

[0012] Phase mainly appearing B alloy in this composition _range, R ² _{T 1 14} B phase (mainly _{R 2} Fe ₁₄ B
Phase) and / or R-rich phase (where R is the same as above, T ¹ is a transition metal consisting of Co or Co and Fe, the same transition metal and M (where M is the same as above), L
Is B, B and M (here M is as defined above) represents) and ^RT _{2 4} B-phase, ^RT _{2 3-phase,} ^RT _{2 2-phase,} R 2 ^{T 2}
₇ phase and RT ² ₅ phase (where R is the same as above, T ² is a transition metal consisting of Co or Co and Fe, the same transition metal and B, the same transition metal and M (where M is the same as above), The transition metal and B and M (where M represents the same as described above), and the like. In the present invention, B containing at least one or two or more phases out of two phases before and after five phases
It is characterized by using an alloy. Note that the phase described as the R-rich phase represents all the various R-rich phases in which the R component is 35 atomic% or more. Of these seven types of phases, _two phases, R ₂ Fe ₁₄ B phase and R-rich phase, are phases that have also appeared by a conventionally known two-alloy method or a normal rare-earth iron-boron-based magnet alloy manufacturing method. is there. The rest of the ^RT ₂ 4 B
Phase, ^RT _{2 3-phase,} ^RT _{2 2-phase,} R ^{₂ T 2} ₇ phase, ^RT _{2 5}
The five types of phases appear by adding 5 atomic% or more of Co to the B alloy, and are unique to the two-alloy method of the present invention. Figure 1 is a cast structure photograph of B alloy of the present invention taken by a scanning electron microscope, the composition in one example determined by EPMA (electron probe X-ray microanalyzer) and X-ray analysis, 1: RT 2 ⁴ _B-phase , 2: RT
² _3-phase, 3: ^RT _{2 2-phase,} 4: the presence of R-rich phase is clearly represented. The two-alloy method according to the present invention is characterized in that at least one of these five phases is contained in the B alloy, and the presence of these phases realizes high magnetic properties in a magnet alloy produced by the two-alloy method. I was able to.

In the present invention, the above alloys A and B are mixed at a specific ratio, and a magnet alloy C is produced by a so-called two-alloy method, whereby high magnetic properties can be exhibited. Less than,
The reason why the presence of these mixed phases in the B alloy resulted in the high magnetic properties of the magnet alloy will be described. The first reason is that these mixed phases have a Curie temperature above room temperature, which was achieved by the additive element Co. Further, these phases have magnetocrystalline anisotropy in a specific crystal direction. Therefore, when a B alloy powder containing one or more of these phases as a main constituent phase is mixed with an A alloy powder mainly composed of R ₂ Fe ₁₄ B phase and oriented in a magnetic field, the B alloy also becomes a ferromagnetic material. , Almost all the grains are oriented with the crystal direction aligned in the direction of the applied magnetic field, and high magnetic properties can be obtained.

The second reason is that the melting points of these phases are in a temperature range suitable for liquid phase sintering of Nd-based rare earth magnets, ie, 700 ° C.
It should be in the range of not less than 1,155 ° C. This temperature range is higher than the melting point of the Nd-rich phase (500-650 ° C),
In addition, the temperature is lower than the melting point (1,155 ° C.) of the R ₂ Fe ₁₄ B phase. Therefore, at the normal sintering temperature, only the Nd-rich phase is present and the viscosity of the melt does not decrease too much, so that the orientation of the particles is not disturbed, and the liquid phase is formed. The density is increased while cleaning the grain boundaries, and high magnet properties are realized after sintering. Another effect of the addition of Co is an improvement in corrosion resistance. The B alloy contains more rare earth elements than the A alloy and thus is easily oxidized and deteriorated. However, by adding Co, the oxidized deterioration can be prevented and stable magnetic properties can be obtained. Addition of Co to the A alloy also improves the corrosion resistance of the alloy, reduces oxidative degradation, and provides stable magnetic properties. Dy added to the B alloy is still present in the vicinity of the grain boundaries even after sintering and aging, and has the effect of improving the coercive force of the magnet alloy C. Similarly, various elements M added to the B alloy (where M is Al, Cu, Zn, In, Si, P, S, Ti, V, Cr,
Mn, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta, W
Represents one or more elements selected from the above) also has the effect of improving the coercive force of the magnet alloy C.

Next, a method for producing the magnet alloy C by the two-alloy method will be described. The A alloy and the B alloy obtained as described above are separately mixed and then mixed at a predetermined ratio. The pulverization is performed by wet or dry pulverization. Rare earth alloys are very active, and are used in an atmosphere such as Ar or nitrogen in the case of dry grinding and in a non-reactive organic solvent such as Freon in the case of wet grinding in order to prevent oxidation during grinding. Done. The mixing step is also performed in an inert atmosphere or a solvent as necessary. The pulverization is generally performed stepwise as coarse pulverization and fine pulverization, but mixing may be performed at any stage.
That is, a predetermined amount may be mixed after coarse pulverization and then finely pulverized, or may be mixed at a predetermined ratio after all pulverization is completed. It is necessary that both the A and B alloys are uniformly mixed with substantially the same average particle size. The average particle size is preferably in the range of 0.5 to 20 μm, and if it is less than 0.5 μm, it is easily oxidized and deteriorated.
If it exceeds sinterability, the sinterability deteriorates.

The mixing ratio of the A alloy powder and the B alloy powder is
It is preferable to mix the B alloy powder in the range of 1 to 30% by weight with respect to 99 to 70% by weight of the alloy powder. If the B alloy powder is less than 1% by weight, the sintering density does not increase and no coercive force is obtained, If it exceeds 30% by weight, the proportion of the nonmagnetic phase after sintering becomes too large, and the residual magnetic flux density becomes small. The obtained mixed powder of the alloy A and the alloy B is molded into a desired size by a molding press in a magnetic field, and further subjected to a sintering heat treatment. Sintering is performed in a vacuum or argon atmosphere at a temperature in the range of 900 to 1200 ° C. for 30 minutes or more, followed by aging heat treatment at a temperature lower than the sintering temperature for 30 minutes or more. After sintering, magnet alloy C
The compact has a density of 95% or more in terms of true density, and a high residual magnetic flux density can be obtained.

[0017]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described with reference to examples, but the present invention is not limited thereto. (Example 1, Comparative Example 1) An alloy of composition formula 12.5Nd-6B-81.5Fe (atomic%) using Nd, Fe metal and ferroboron having a purity of 99.9% by weight in an Ar atmosphere of a high-frequency melting furnace. After melting and casting, the ingot is heated at 1,070 ° C in an Ar atmosphere.
Solution was obtained for 20 hours. This is an A1 alloy. Next, an alloy of the composition formula 20Nd-10Dy-20Fe-6B-40Co-4Al is also melt-cast in an Ar atmosphere using a high-frequency melting furnace using Nd, Dy, Fe, Co, Al metal and ferroboron having a purity of 99.9% by weight. This was used as a B1 alloy. A1 alloy ingot and B1 alloy ingot are separately coarsely pulverized in a nitrogen atmosphere.
The mesh was made smaller than the mesh, and then the B1 alloy coarse powder was weighed at 90% by weight and the B1 alloy coarse powder at 10% by weight, and mixed in a nitrogen-purged V blender for 30 minutes. This mixed coarse powder was finely pulverized with a jet mill using high-pressure nitrogen gas to an average particle size of about 5 μm. The obtained mixed fine powder was press-molded at a pressure of about 1 Ton / cm ² while being oriented in a magnetic field of 15 kOe. Then
This compact was sintered at 1,070 ° C for 1 hour in a sintering furnace in an Ar atmosphere, and further quenched by aging heat treatment at 530 ° C for 1 hour.
Magnet alloy C1 was produced.

For comparison, an alloy having the same composition as in Example 1 was produced by a conventional one-alloy method, and Comparative Example 1 was obtained. That is,
The same composition (magnet alloy C1) as after mixing both alloys A1 and B1 was weighed from the beginning, melted, pulverized, sintered, and subjected to aging heat treatment.
The magnet characteristics were compared with the magnet by the alloy method (magnet composition C1 of Example 1). The composition of this magnet alloy C1 was 13.1 Nd- in both Example 1 by the two-alloy method and Comparative Example 1 by the one-alloy method.
0.8Dy-3.2Co-6.0B-0.3Al-76.6Fe. Table 1 shows the values of the magnetic properties and the sintered body densities obtained for both sintered body magnets of Example 1 and Comparative Example 1. The magnetic properties of Example 1 are almost the same as those of Comparative Example 1, but the density of the sintered body is almost the same. However, Example 1 is far superior in all values such as residual magnetic flux density, coercive force, and maximum energy product. I have. As described above, even if the composition of the magnet alloy C is exactly the same, there is a considerable difference in the magnetic properties, indicating that the two-alloy method is a very effective method for improving the magnetic properties of the Nd magnet. The metal structure of the B1 alloy in the cast state is shown in FIG. 1 by a backscattered electron image photograph of a scanning electron microscope. As can be seen from the light and dark of the photograph, there are four main constituent phases in the B1 alloy. Each phase, EPMA by (electron probe X-ray microanalyzer) and X-ray analysis, RT ² ₄ B-phase as shown in FIG, RT ² _3-phase, RT ² ₂
Phase, an R-rich phase.

(Examples 2 to 24, Comparative Examples 2 to 24) As shown in Tables 1, 2 and 3, corresponding to the alloy compositions of Examples 2 to 24, the compositions of A alloys A2 to A24 corresponded to the alloy compositions of Examples 2 to 24. An alloy was prepared, and a composition alloy of B2 to B24 was prepared as a B alloy. Thereafter, pulverization was performed in the same manner as in Example 1, mixed at a predetermined ratio, molded in a magnetic field, and sintered (1,050 to 1,120 ° C. × 1 hour).
An aging treatment (500 to 650 ° C. for 1 to 10 hours) was performed to produce 2-alloy magnet alloys C2 to C24, and the magnetic properties were measured and are shown in Tables 1, 2 and 3. For comparison, alloys having the same composition as in Examples 2 to 24 were manufactured by the same alloy method as in Comparative Example 1 to produce magnet alloys C2 to C24, and their magnetic properties were measured to obtain Comparative Examples 2 to 24. 2, shown in Table 3.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

The rare-earth permanent magnet produced according to the present invention has several steps more excellent magnetic properties than conventional rare-earth magnets having the same composition by effectively utilizing expensive additional elements, and has a high coercive force and high coercive force. It has become possible to provide a high-performance magnet with a good balance of residual magnetic flux density and high energy product. Therefore, it is expected that it will be widely used as a high-performance magnet for various electric and electronic devices in the future.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph showing a metal structure of a B1 alloy of Example 1 in a cast state.

[EXPLANATION OF SYMBOLS] 1 RT ² ₄ B-phase 2 RT ² _3-phase 3 RT ² ₂ Phase 4 R-rich phase

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-288305 (JP, A) JP-A-1-111184 (JP, A) JP-A-63-313807 (JP, A) JP-A-3- 250607 (JP, A)

Claims (4)

(57) [Claims] 1. An alloy A mainly composed of an R ₂ T ₁₄ B phase (where R represents at least one or more rare earth elements mainly composed of Nd, Pr, and Dy, and T represents Fe or Fe and Co). Alloy, and B alloy is R, Co, Fe, B,
M (where R is the same as above, M is Al, Cu, Zn,
In, Si, P, S, Ti, V, Cr, Mn, Ge, Z
r, Nb, Mo, Pd, Ag, Cd, Sn, Sb, H
f, Ta, or W, which represents one or more elements selected from the group consisting of 20 <R ≦ 40, 0.1 ≦ Fe ≦
55, 15 ≦ Co ≦ 80, 0.1 ≦ B ≦ 20, 0.1 ≦
The composition range of M ≦ 20 (both atomic%), One or, B if <br/> R ₂ T ¹ ₁₄ L-phase as a phase in the alloy and / or R-rich phase (here R is as defined above , T ¹ is a transition metal consisting of Co or Co and Fe, the transition metal and M (where M is the same as above), L represents B, B and M (where M is the same as above), and RT ² ₄ L-phase, RT ² _3-phase, R
T ² _2-phase, R ₂ T ² ₇ phase and RT ² ₅ phase (here R and L
Is the same as above, T ² is a transition metal composed of Co or Co and Fe, the same transition metal and B, the same transition metal and M
(Where M is the same as above), one or more of the five phases of the same transition metal and B and M (where M is the same as above), and one of the five phases Or two or more
At least one of the phases has a melting point of at least 700 ° C.
An alloy consisting of a mixed phase with a phase of 1,155 ° C. or lower is mixed, and B alloy powder is mixed at a ratio of 1 to 30% by weight with respect to 99 to 70% by weight of the A alloy powder. A method for producing a rare earth permanent magnet, comprising: performing medium pressure molding; sintering the molded body in a vacuum or an inert gas atmosphere; and performing aging heat treatment at a low temperature equal to or lower than a sintering temperature. 2. A B alloy according to claim 1, wherein B
RT ₄ L phase that is part of the alloy, RT ₃ phase, RT ₂ phase, R ₂ T ₇
Phase and one or two of the five constituent phases of the RT ₅ phase
A method for preparing a rare earth permanent magnet, characterized in that more of the phases of one or more phases even without least is a magnetic material having the above Curie temperature room. 3. The B alloy according to claim 1 , wherein said B alloy
Alloy included Ru RT ₄ L-phase, RT ₃ phase, RT ₂ phase, R ₂ T ₇
Phase and one or two of the five constituent phases of the RT ₅ phase
Rare-earth manufacturing method of a permanent magnet, characterized in that more of the phases of a magnetic material in which one or more phases having a Curie temperature and crystal magnetic anisotropy of more than room temperature even without low. 4. A alloy, the average particle size of B alloys and AB mixed alloy powder, according to any one of claims 1 to 3 you being in the range of 0.5 ～20Myuemu Nozomi <br/> earth manufacturing method of a permanent magnet.