JPH0613215A - Rare earth compound magnet having magnetic anisotropy - Google Patents

Abstract

PURPOSE:To realize the excellent magnetic characteristics having enhanced magnetic anisotropy and higher residual flux density in the case of compound magnetization by coupling specific anisotropic particles with a binder to be used as the material for a compound magnet. CONSTITUTION:The alloy particles in the composition having the values meeting the requirements of R: 10-20 atomic % (R: containing at least one kind of rare earth elements and exceeding 50 atomic % of one or more than kind of Pr or Nd out of R) T:67-85 atomic % (T: Fe or part of Fe is substituted for not exceeding 50 atomic % of Co), the quantity of B+C = 4-10 atomic %, C/(B+C) = 0.01-0.8 are formed. At this time, exceeding 70vol% of the alloy particles is a compound having tetragonal Nd2Fe14B type crystalline structure furthermore, 0.05-1mum of the crystalline particle diameter of exceeding 50% of volumic ratio of the compound and 10-1000mum of mean particle diameter as well as 0.9-1.6T of the residual flux density in the magnetization facilitating direction. Finally, the alloy particles are coupled with a binder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to R (rare earth element) -T (iron group element) -M (additive element) -which has a high coercive force and can be used in various motors and actuators.
Relates to B-C rare earth-based composite magnet, in particular heat treatment of the present system coarsely pulverized powder with H ₂ gas, and resulted in the removal of H ₂ treatment for heating and maintaining at a predetermined atmosphere, and very fine crystals of the crystalline grains 1μm or less R having high magnetic anisotropy and high coercive force
The present invention relates to a rare earth-based composite magnet having magnetic anisotropy, which is made into a composite magnet by using an alloy powder for a T-M-B-C based permanent magnet.

[0002]

2. Description of the Related Art A method for producing a rare earth alloy powder for permanent magnets by a hydrogen treatment method is disclosed in, for example, Japanese Patent Laid-Open No. 1-132106. The hydrogen treatment method is RT-
The MB raw material alloy ingot or powder is kept at a temperature of 500 ° C. to 1000 ° C. in a H ₂ gas atmosphere or a mixed atmosphere of H ₂ gas and an inert gas so that H ₂ is absorbed in the alloy ingot or powder. And then H ₂ gas pressure 13 Pa
(1 × 10 ^-1 Torr) until the following vacuum atmosphere or H ₂ gas partial pressure 13 Pa (1 × 10 ^-1 Torr) or less inert gas atmosphere, de-H at a temperature 500 ° C. to 1000 ° C.
₂ treatment, followed by cooling, RT-
It is a method for producing an M-B alloy powder.

[0003]

The R-T-M-B type alloy powder produced by the above method has large coercive force and magnetic anisotropy. This treatment results in a structure having a very fine recrystallized grain size, that is, an average recrystallized grain size of substantially 0.1 to 1 μm, which is magnetically tetragonal Nd ₂ Fe ₁₄ B.
This is because the crystal grain size is close to the single domain critical grain size of the system compound, and these ultrafine crystals are recrystallized to some extent with their crystal orientations aligned. Further, the R-T-M-B based alloy powder obtained by the above-mentioned manufacturing method does not change its characteristics due to external stress such as crushing and pressurization, and also in a fine powder region of 25 μm or less. The coercive force does not decrease, and this property is suitable as a raw material for a composite magnet that is mixed with a binder to form a compact.

However, the RT- manufactured by the above method
The magnetic properties of the alloy powder for MB magnets are insufficient particularly in terms of magnetic anisotropy, do not reach the magnetic anisotropy inherent in the raw material alloy itself, and remain in terms of magnetic properties. There is a drawback that the magnetic flux density Br is small.

The present invention improves the magnetic anisotropy of the R-T-M-B type alloy powder to have a high residual magnetic flux density Br in the case of forming a composite magnet and has excellent magnetic properties. −
The purpose is to provide a B-based composite magnet.

[0006]

In order to increase the residual magnetic flux density Br in the present invention, the raw material composition was examined, and as a result, a substitution element and an addition element capable of obtaining a large magnetic anisotropy were found. Is. That is, it was found that a large magnetic anisotropy can be stably obtained by substituting a part of B with C. Furthermore, Al, C
r, Ni, Ga, Zr, In, Sn. Hf, Ti, V,
It has been found that the addition of one or more of Nb, Mo, Ta and W improves and improves the magnetic characteristics.
Further, by limiting the composition range of such a component system, setting the hydrogen pressure in the hydrogen treatment method to 10 kPa or more and the hydrogen pressure in the dehydrogenation step to 10 Pa or less, a powder having stable magnetic anisotropy can be produced. It was found that this anisotropic powder can be used as a raw material for a composite magnet combined with a binder, and the present invention was completed.

That is, according to the present invention, R: 10 to 20 atomic% (R: at least one rare earth element and one or two Pr or Nd contained in 50 or more atomic% of R), T: 67 ~ 85 atomic% (T: Fe or 1 of Fe
Part is replaced by 50 atomic% or less of Co), and the amounts of B and C are
B + C = 4 to 10 atom% C / (B + C) = 0.01 to
Consisting of an alloy powder having a value satisfying 0.8,
70 vol% or more of the alloy powder is a compound having a tetragonal Nd ₂ Fe ₁₄ B type crystal structure, and at least 50% or more by volume of the compound has a crystal grain size of 0.05 to 1 μm.
And a rare earth element having magnetic anisotropy, characterized in that an alloy powder having an average particle diameter of 10 to 1000 μm and a residual magnetic flux density in the easy magnetization direction of 0.9 to 1.6 T is combined with a binder. System composite magnet.

Further, according to the present invention, R: 10 to 20 atomic%
(R: at least one rare earth element and Pr or N
1 or 2 kinds of d are contained in R of 50 atom% or more),
T: 67 to 85 atomic% (T: Fe or 1 part of Fe is 5
Substituted with 0 atomic% or less of Co), M; 10 atomic% or less (M; Al, Ti, V, Cr, Ni, Ga, Zr, N
b, Mo, In, Sn, Hf, Ta, W, one or more, and the amounts of B and C are B + C = 4 to 10 atom%.
C / (B + C) = consisting of an alloy powder having a composition satisfying a value of 0.01 to 0.8, 70 vol% of the alloy powder
The above is a compound having a tetragonal Nd ₂ Fe ₁₄ B type crystal structure, and at least 50% by volume of the compound has a crystal grain size of 0.05 to 1 μm and an average grain size of 10 to 1.
A rare earth-based composite magnet having magnetic anisotropy, characterized in that an alloy powder having a residual magnetic flux density of 000 μm and having a residual magnetic flux density in the easy magnetization direction of 0.9 to 1.6 T is bonded to a binder.

Reasons for limiting the composition R used in the raw material alloy used in the present invention, that is, the rare earth elements are Y, La, Ce, Pr, Nd, Sm, Gd,
Tb, Dy, Ho, Er, Tm, Lu are included, and at least one of them is contained and at least one or two of Pr and Nd are contained in 50 at% or more of R.
Further, all of R may be one or two of Pr and Nd. The reason why 50 atomic% or more of R is at least one of Pr and Nd is that sufficient magnetization cannot be obtained if the atomic ratio is less than 50 atomic%.

When R is less than 10 atomic%, the coercive force is lowered due to precipitation of αFe phase, and when it exceeds 20 atomic%, in addition to the intended tetragonal Nd ₂ Fe ₁₄ B type compound, R-rich second If a large amount of phases are precipitated and the amount of the second phase is too large, the magnetization of the alloy is reduced. Therefore, the range of R is 10 to 20 atomic%.

T is an iron group element, and Fe or a part of Fe can be replaced by 50% or less of Co. If T is less than 67 atomic%, the second coercive force and low magnetization precipitates and the magnetic properties are deteriorated. If it exceeds 85 atomic%, the coercive force and squareness are deteriorated due to the precipitation of αFe phase. , 67 to 85 atomic%. Further, addition of 50% or less of Co is effective for improving the Curie temperature, but when Fe is less than 50% in the atomic ratio of Fe and Co, the amount of decrease in the saturation magnetization of the Nd ₂ Fe ₁₄ B type compound itself is large. Because it will be T
Of these, Fe was 50% or more in terms of atomic ratio.

Of M, Al, Cr, Ni, Ga, Z
r, In, Sn, and Hf are effective elements for growing the recrystallized grains at the time of the H ₂ removal treatment to a size of 0.05 to 1 μm and imparting magnetic anisotropy to the powder, and C addition. At times, it is necessary to obtain stable magnetic anisotropy. Ti,
V, Nb, Mo, Ta, and W have an effect of preventing the recrystallized grains from being coarsened to 1 μm or more during the H ₂ removal treatment, and as a result, suppressing a decrease in coercive force. Therefore, M
However, it is a good idea to use the above elements in combination depending on the purpose. When the addition amount exceeds 10 atomic%, the second phase which is not ferromagnetic precipitates and the magnetization is lowered, so M is preferably 10 atomic% or less.

Regarding B, it is essential for stable precipitation of a tetragonal Nd ₂ Fe ₁₄ B type crystal structure, but it is possible to partly replace it with C described later. The addition amount is
When the sum of B and C is 4 atomic% or less, the R ₂ T ₁₇ phase precipitates to lower the coercive force, and the squareness of the demagnetization curve is significantly impaired. Further, when added in excess of 10 atomic%, the second phase having a small magnetization precipitates and reduces the magnetization of the powder, so the sum of B and C was set to 4 to 10 atomic%. Also, C /
The reason for limiting (B + C) = 0.01 to 0.8 is 0.
When it is less than 01, there is no effect of improving the magnetic anisotropy of the alloy powder after hydrogen treatment, and when it exceeds 0.8, R carbide is easily generated and the Th ₂ Zn ₁₇ type structure is stabilized in a high temperature range. There is a risk that the amount of αFe precipitation will increase, the tetragonal ratio in the ingot will decrease, and not only the residual magnetic flux density will decrease, but also the coercive force of the alloy powder after hydrogen treatment will decrease significantly, which is not desirable. , C / (B + C) is more preferably 0.1 to 0.5.

Reason for Limitation of Alloy Powder Structure In the present invention, if the abundance ratio of the tetragonal Nd ₂ Fe ₁₄ B type compound is less than 70 vol%, the magnetic properties, especially the residual magnetic flux density are lowered. More specifically, the coercive force is reduced when the mixed second phase is the αFe phase, and the magnetization is reduced when the mixed second phase is the R-rich phase or the B-rich phase. Therefore, the abundance ratio of the tetragonal Nd ₂ Fe ₁₄ B type compound is set to 70 vol% or more. In order to obtain a coarsely pulverized powder having a tetragonal Nd ₂ Fe ₁₄ B type compound in a volume ratio of 70% or more, it is preferable to anneal at a temperature of 800 ° C. to 1200 ° C. for 1 hour or more at the alloy ingot stage, Means such as controlling the cooling rate of the mold in the ingot making process may be appropriately selected. The abundance ratio of tetragonal crystals in this ingot is maintained almost as it is even after the hydrogen treatment.

In the present invention, tetragonal Nd ₂ Fe ₁₄ B
High coercive force can be obtained when the type compound has a crystal grain size of 1 μm or less. However, even if there is a crystal grain size of 1 μm or less, if crystals of 1 μm or less are present in a volume ratio of 50% or more, the compound as a whole is High coercive force can be maintained. Also, 0.0
Crystals having a size of 5 μm or less are practically difficult to manufacture, and even if they are obtained, there are no particularly excellent magnetic properties. Therefore, the crystal grain size of the Nd ₂ Fe ₁₄ B-type compound, which is the main phase, is 0.05 to 1 μm when the volume ratio is 50% or more.
It is preferable that the crystals are occupied. More preferably, crystals of 0.1 to 0.5 μm occupy 80% or more by volume.

Reason for Limitation of Residual Magnetic Flux Density The alloy powder for permanent magnets according to the present invention is characterized by having a magnetically high anisotropy. The saturation magnetization of the Nd ₂ Fe ₁₄ B type compound, which is the main phase of this alloy powder, is 1.6 T, and the residual magnetic flux density of the alloy powder cannot exceed 1.6 T. On the other hand, when the residual magnetic flux density is less than 0.9T, theoretically, there is no superior magnetic property to the rare earth alloy powder for isotropic permanent magnets that can obtain a residual magnetic flux density of 0.8T, It has no practical meaning. Therefore, the value of the residual magnetic flux density is set to 0.9 to 1.6T.

Manufacturing Conditions The manufacturing method of the rare earth-based composite magnet having magnetic anisotropy of the present invention will be described below. 1) R: 10 to 20 atomic%
(R: at least one rare earth element and Pr or N
1 or 2 kinds of d are contained in R of 50 atom% or more),
T: 67 to 85 atomic% (T: Fe or 1 part of Fe is 5
Substituted with 0 atomic% or less of Co), or further M;
10 atomic% or less (M; Al, Ti, V, Cr, Ni, G
a, Zr, Nb, Mo, In, Sn, Hf, Ta, and W), and contains B and C in an amount of B.
+ C = 4 to 10 atom% C / (B + C) = 0.01 to
After roughly crushing an alloy ingot having a composition having a value satisfying 0.8, 2) 10 kPa as the raw powder.
Heated and held at 500 ° C to 900 ° C for 15 minutes to 8 hours in H ₂ gas of up to 1000 kPa, and 3) further H ₂ partial pressure of 10P.
After de-H ₂ treatment of holding at 500 ° C. to 900 ° C. for 15 minutes to 8 hours at a or less and then cooling, 4) 70 vol% or more of the alloy powder has a tetragonal Nd ₂ Fe ₁₄ B type crystal structure. A compound, and at least 50% or more by volume of the compound has a crystal grain size of 0.05 to 1 μm, an average grain size of 10 to 1000 μm, and a residual magnetic flux density in the easy magnetization direction of 0.9 to After obtaining an alloy powder having 1.6T, 5) the alloy powder is combined with a binder to form a composite magnet.

The hydrogen treatment method is characterized in that a coarsely pulverized powder having a required particle size does not change its size in appearance and an aggregate having an extremely fine crystal structure can be obtained. That is, when a tetragonal Nd ₂ Fe ₁₄ B type compound is reacted with H ₂ gas at a high temperature, phase separation occurs into RH _{2 ■ 3} , αFe, Fe ₂ B, etc.
Further, when the H ₂ gas is removed by the H ₂ removal treatment, a recrystallized structure of the tetragonal Nd ₂ Fe ₁₄ B type compound is obtained again.

The starting material may be coarsely pulverized by a conventional mechanical pulverization method or a gas atomizing method, or a so-called hydrogen pulverization method by occluding H ₂ may be used. The crushing step and the hydrogen treatment method for obtaining ultrafine crystals may be continuously performed in the same apparatus. The average particle size of the obtained coarsely pulverized powder is 50 to 1000 μm.
Is preferred.

[0020] In this invention, when heating with H ₂ gas, H in ₂ gas pressure is less than 10 kPa, it does not proceed sufficiently that the above decomposition reaction, also processing facility becomes too large and exceeds 1000 kPa, industrial Since it is not preferable in terms of cost and safety, the pressure range is 10 kPa-10
It was set to 00 kPa. More preferably 50 kPa to 15
It is 0 kPa.

The heat treatment temperature in H ₂ gas is 500 ° C.
If the temperature is less than 1, the decomposition reaction into RH _{2 ■ 3} , αFe, Fe ₂ B, etc. does not occur, and if it exceeds 900 ° C., the RH _{2 ■ 3} becomes unstable, and the product grows to form tetragonal Nd ₂ Fe _14. B
Since it becomes difficult to obtain an ultrafine crystal structure of the type compound, the temperature range is set to 500 ° C to 900 ° C. Regarding the heat treatment holding time, it is necessary to hold the heat treatment for 15 minutes to 8 hours in order to sufficiently carry out the above decomposition reaction.

The H ₂ partial pressure during de H ₂ treatment of the present invention, 10
It exceeds Pa the temperature range below, i.e. either does not lead to decomposition conditions RH 2 _{■ 3-phase} at 900 ° C. or less, practical de H ₂ rate is obtained even in the equilibrium theory has reached the cracking conditions no order, H ₂ partial pressure at the time of de-H ₂ process was 10Pa or less.

In the present invention, the temperature for the H ₂ removal treatment is 5
When the temperature is lower than 00 ° C., H ₂ is not released from the RH _{2 3} phase, and therefore the tetragonal Nd ₂ Fe ₁₄ B type compound is not recrystallized. Further, when the temperature exceeds 900 ° C., tetragonal Nd ₂ Fe ₁₄ B
A type compound is produced, but recrystallized grains grow coarsely and a high coercive force cannot be obtained. Therefore, the temperature range of the H ₂ removal treatment is 500 ° C. to 900 ° C. Further, the heat treatment holding time is required to be 15 minutes to 8 hours in order to sufficiently carry out the above recrystallization reaction.

The recrystallized grain size of the de H ₂ treatment tetragonal Nd ₂ Fe ₁₄ B type compound after is substantially difficult to obtain an average recrystallized grain size below 0.05 .mu.m, also obtained if Even if it does, there is no advantage in magnetic characteristics. On the other hand, if the average recrystallized grain size exceeds 1 μm, the coercive force of the powder decreases, which is not preferable. Therefore, the average recrystallized grain size is 0.05 to
It was 1 μm.

The binder used in the present invention is not particularly limited in kind regardless of resin or metal, but an optimum binder is appropriately selected according to a molding method described later. For example, in the case of the compression molding method, a thermosetting resin such as an epoxy resin is often used, and heating is performed as a curing treatment after molding. In addition, a thermoplastic resin such as nylon is used in the injection molding method, and curing treatment is not particularly required. In the case of a metal binder, the melting point of the metal used as the binder is selected mainly depending on the usage conditions of the composite magnet. Further, when the water permeability of the resin binder is disliked or the gas released from the resin binder is disliked, the metal binder is selected. For example, Z
There are n, In, Sn, Pb and alloys thereof, and they are appropriately selected from metals and alloys having a melting point in the range of 150 to 500 ° C. In the present invention, the amount of the binder is 0.5 to 20 wt% in the case of the resin binder, preferably 1 to 10 wt% in the compression molding method, 1 to 10 wt% in the extrusion molding, and injection molding, In the case of sheet-like molding, it is 3 to 20 wt%, in the case of impregnating it after molding, it is 0.5 to 5 wt% depending on the porosity of the molded body, and in the case of a metal binder, it is 5 to 50 wt%.
When the amount of the above binder is less than the lower limit value,
Molding becomes difficult, many voids remain inside, the strength becomes insufficient, and grain breakage easily occurs. Further, orientation by an external magnetic field during molding becomes difficult, and magnet characteristics deteriorate. When the amount of the binder is more than the upper limit value, magnetic properties such as magnetic flux density and energy product are deteriorated, which is not preferable.

The molding method is not particularly limited, but the compression molding method and the injection molding method are common methods for molding by applying a magnetic field. Further, it is also possible to integrally form with the yoke material. The extrusion molding method is a highly productive method particularly for producing a long magnet. In addition, a thin-walled magnet can be manufactured by preparing a sheet-shaped slurry on a base film, punching it into a required shape, and performing a curing treatment. Further, only the raw material powder may be molded in a magnetic field, taken out, and then impregnated with the binder.

[0027]

In the RTB composite magnet according to the present invention, a large magnetic anisotropy can be stably obtained by substituting C for a part of B, and the residual magnetic flux density Br can be increased. , Al, Cr, Ni, Ga, Zr, In,
Sn. It is possible to improve and improve the magnetic characteristics by adding one or more of Hf, Ti, V, Nb, Mo, Ta and W. Furthermore, R-T of a specific composition range
-M-B-C system alloy coarsely pulverized powder is used, the hydrogen pressure in the hydrogen treatment method is set to 10 kPa or more, and the hydrogen pressure in the dehydrogenation step is set to 10 Pa or less, so that the average crystal grain size is 0.05 to 1 μm. It is possible to stably obtain a magnetic powder having a high magnetic anisotropy composed of recrystallized grains and having a high coercive force, and to improve the magnetic characteristics of the composite magnet combined with the binder.

[0028]

Example 1 No. 1 shown in Table 1 obtained by melting by a high frequency induction melting method. The ingots having the compositions of 1 to 14 were annealed at 1100 ° C. for 24 hours in a vacuum of 10 Pa or less so that the volume ratio of the tetragonal Nd ₂ Fe ₁₄ B type compound in the ingot was 90% or more.
This ingot was placed in an Ar gas atmosphere (O ₂ amount of 0.5% or less).
After roughly pulverizing with a stamp mill to an average particle size of 100 μm, this coarsely pulverized powder was put into a tubular furnace and evacuated to 1 Pa or less. Then, the purity of 99.9999% or more 10
While introducing H ₂ gas of 0 kPa, the raw material temperature was kept at 800 ° C. for 2 hours. Subsequently, while keeping the raw material at 800 ° C., the supply of H ₂ gas was stopped, the inside of the furnace was evacuated by a rotary pump and an oil diffusion pump, and it was kept for 1 hour.
The pressure inside the raw material processing chamber at this time is finally 0.05 Pa.
Fell to. After that, Ar gas having a purity of 99.999% or more was introduced into the furnace, and the raw material was cooled to a raw material temperature of 5
The raw material was taken out when the temperature became 0 ° C or lower. Each of the obtained magnet powders has a crystal grain size of 0.05 to 1 μm in a volume ratio of 80% to 95% and an average grain size of 0.
It was in the range of 3 μm to 0.5 μm. The coercive force HcJ, the magnetization I, and the residual magnetic flux density Br in the easy magnetization direction are measured and shown in Table 1. The value of magnetization is 0.8 M in the external magnetic field.
The value at A / m was measured by orienting in a magnetic field. To this raw material powder, a thermosetting epoxy resin 3 is used as a binder.
After mixing wt%, in a magnetic field of 0.8 MA / m, 3.0t
compression-molded at a pressure of on / cm ² and then 150 ° C. for 1
The resin was cured under the conditions of time to produce a rare earth composite magnet. The coercive force HcJ, the magnetization I, and the residual magnetic flux density Br in the easy magnetization direction of each magnet are measured and shown in Table 2.

Comparative Example No. 1 shown in Table 1 The coarsely pulverized powders having three types of compositions of 15 to 17 were treated in the same manner as in the example to obtain alloy powder for permanent magnet by hydrogen treatment. The coercive force HcJ, the magnetization I, and the residual magnetic flux density Br of the obtained magnet powder according to the comparative example are measured and shown in Table 1. In addition, as in Example 1, 3 wt% of thermosetting epoxy resin was mixed as a binder to prepare a rare earth composite magnet, and the coercive force HcJ, magnetization I, and
The residual magnetic flux density Br in the easy magnetization direction is measured and shown in Table 2.

Example 2 No. 1 shown in Table 1 Aminosilane-based coupling material (0.5 wt%), titanate-based coupling material (0.5 wt%) and Ar gas were mixed with 9 to 9 magnet powders of 6 to 14 and then Nylon 12 was used as a binder. 8w
t% was mixed and kneaded in Ar gas at 230 ° C. for 15 minutes to prepare a compound. This compound was loaded into an injection molding machine, and injection molding was performed under the conditions of 280 ° C. and an applied magnetic field of 0.8 MA / m to produce a rare earth composite magnet. The coercive force HcJ, the magnetization I, and the residual magnetic flux density Br in the easy magnetization direction of each magnet are measured and shown in Table 2.

Example 3 No. 1 shown in Table 1 Zn powder as a binder was mixed at 25 wt% with 9 kinds of magnet powders of 6 to 14 and then compression molded at a pressure of 3.0 ton / cm ^{2 in} a magnetic field of 0.8 MA / m and taken out. After that, heat treatment was performed at 425 ° C. for 15 minutes in an Ar gas atmosphere to produce a rare earth composite magnet. The coercive force HcJ, the magnetization I, and the residual magnetic flux density Br in the easy magnetization direction of each magnet are measured and shown in Table 2.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

According to the composition of the present invention, R-T-M-B-
C-based permanent magnet powder has a specific composition range of R-T-M-B.
-C-based coarsely pulverized powder is heat-treated at a hydrogen pressure of 10 kPa or more in a high-purity H ₂ gas released from, for example, a hydrogen storage alloy, and de-H ₂ treatment is performed by heating and holding the hydrogen pressure at a predetermined atmosphere of 10 Pa or less. By carrying out, it is possible to obtain a magnetic alloy powder having a large magnetic anisotropy and a high coercive force, which is composed of recrystallized grains having an average crystal grain size of 0.05 to 1 μm, and is combined with various binders. A high-performance composite magnet can be manufactured.

Claims (2)

[Claims] 1. R: 10 to 20 atomic% (R; at least one rare earth element and one or two Pr or Nd).
Species are contained in R of 50 atomic% or more), T: 67 to 85 atomic% (T: Fe or a part of Fe is 50 atomic% or less of C).
the amount of B and C is B + C = 4 to 10 atom%.
C / (B + C) = consisting of an alloy powder having a composition satisfying a value of 0.01 to 0.8, 70 vol% of the alloy powder
The above is a compound having a tetragonal Nd ₂ Fe ₁₄ B type crystal structure, and at least 50% by volume of the compound has a crystal grain size of 0.05 to 1 μm and an average grain size of 10 to 1.
A rare earth-based composite magnet having magnetic anisotropy, characterized in that an alloy powder having a residual magnetic flux density of 000 μm and having a residual magnetic flux density in the easy magnetization direction of 0.9 to 1.6 T is bonded to a binder. 2. R: 10 to 20 atomic% (R; at least one rare earth element and one or two Pr or Nd).
Species are contained in R of 50 atomic% or more), T: 67 to 85 atomic% (T: Fe or a part of Fe is 50 atomic% or less of C).
Substituted with o), M; 10 atomic% or less (M; Al, Ti,
V, Cr, Ni, Ga, Zr, Nb, Mo, In, S
one or more of n, Hf, Ta, W), B,
The amount of C is B + C = 4 to 10 atomic% C / (B + C) =
It is composed of an alloy powder having a composition satisfying a value of 0.01 to 0.8, and 70 vol% or more of the alloy powder is tetragonal Nd.
₂ Fe ₁₄ B-type crystal structure compound, and the crystal grain size of at least 50% by volume of the compound is 0.
The average particle diameter is 05 to 1 μm, the average particle diameter is 10 to 1000 μm, and the residual magnetic flux density in the easy magnetization direction is 0.9 to 1.6.
A rare earth-based composite magnet having magnetic anisotropy, characterized in that an alloy powder having T is combined with a binder.