JPH09256001A - Alloy for r-t-b base anisotropic magnet, production of alloy powder and alloy for inspecting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the hydrogenizing and recrystallizing treating conditions by discharging an alloy for inspecting in the process of hydrogenizing the alloy powder and confirming intermediate stage phases. SOLUTION: The temp. of the raw powder of an R-T-(M) base alloy is raised, which is hydrogenized, is discharged in the process of the treatment and is rapidly cooled to obtain an alloy for inspecting. As for intermediate stage phases confirmed by this alloy for inspecting, in addition to a lamellar structure composed of coarse α-Fe and Fe2 B grains and α-Fe and RH2 , contg. R2 Fe14 B fine grains and RH2 on the direction same as that of mother phases, Fe enriched alloy phases contg. <=10at.% are largely present, but, they vanish by the prolongation of the hydrogenizing time. Then, in the process of the hydrogenizing, this Fe enriched alloy phases, i.e., the intermediate stage phases are confirmed, and while the formation of the R2 Fe14 B fine grains and their convertion into anisotropic ones are verified, it is regulated to an optimum alloy phase structure, i.e., the optimum conditions are set, by which the fine crystals of the R2 Fe14 B phases can uniformly be dispersed into the intermediate stage phases by the hydrogenizing treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a newly discovered inspection alloy that can be utilized in a method for producing an R-T-B type anisotropic bonded magnet alloy powder by hydrogenation / recrystallization treatment. When manufacturing the alloy powder for anisotropic bonded magnets, a newly discovered test alloy having an intermediate stage phase in the middle of hydrogenation of the alloy powder is taken out during the manufacturing process to obtain R ₂ Fe.
_The present invention relates to a method for producing an R-T-B based anisotropic magnet alloy powder capable of adjusting to an appropriate alloy phase structure while verifying the generation and anisotropic processes of fine particles of B, and an alloy for inspection.

[0002]

2. Description of the Related Art A method for producing an RT- (M) -B anisotropic bonded magnet powder is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-132106 as a production method by hydrogenation / recrystallization treatment. There is. That is, the hydrogenation / recrystallization treatment method means that the RT- (M) -B-based raw material alloy ingot or powder is
After maintaining the 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 to occlude H ₂ in the ingot or powder of the above alloy, H ₂ gas pressure 13P
a (1 × 10 ⁻¹ Torr) or less vacuum atmosphere or H ₂
H removal at a temperature of 500 ° C to 1000 ° C until an inert gas atmosphere having a gas partial pressure of 13 Pa (1 x 10 ^-1 Torr) or less is obtained.
₂ Treatment, and then cooling. In this publication, the powder obtained by the hydrogenation / recrystallization treatment is crushed and then resin-blended to obtain an RTB anisotropic bonded magnet. Is disclosed.

Further, various heat patterns by the hydrotreating method have been disclosed, and it has been proposed to add an ingot homogenizing treatment.
The 00 ° C. to 1200 alloy powder was homogenized at ° C. in a mixed atmosphere of an inert gas in H ₂ or H ₂ and 500 ° C. to 100
Hold at 0 ° C. to occlude H ₂ and then 500 ° C. to 1
A method of vacuum degassing at 000 ° C. and cooling has been proposed (JP-A-2-4901).

The RTB-based alloy magnet produced by such a hydrogenation / recrystallization treatment method has a 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 μm to 1 μm, which is magnetically tetragonal R 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 with the crystal orientation aligned to some extent. It is considered that this crystal orientation is the same as that of the raw material alloy powder even after the hydrogenation / recrystallization treatment.

[0005]

However, R-T-obtained by the hydrotreating method disclosed in JP-A-1-132106 and JP-A-2-4901.
The magnetic properties of the (M) -B system alloy powder for magnets are about 0.1 T lower than the magnetization of the raw material ingot at 1.2 MA / m. That is, there is a drawback that the degree of anisotropy is lowered by the processing.

Further, in the method of performing the crushing step of the raw material ingot disclosed in Japanese Patent Laid-Open No. 4-141502 by spontaneously disintegrating the alloy with hydrogen in a closed container, instability generated in the alloy during hydrogen crushing RH _{2 + X} (0 ≦ X ≦ 1)
When exposed to the atmosphere, it has a very strong tendency to react with the atmosphere and oxidize, so the oxidization of the alloy powder cannot be avoided, and when the powder oxidizes, the anisotropic magnet powder obtained by hydrogenation The degree of anisotropy cannot be expected to improve because the degree of deterioration tends to decrease.

That is, the R-T-B type bonded magnet made of the powder produced by the hydrogenation / recrystallization treatment method as a raw material is a hydrogenation / recrystallization treatment method depending on the structure of the alloy ingot used for the treatment and the pulverization method. There was a drawback in that the magnetization of the powder produced in 1. was reduced.

Conventionally, the hydrogenation / recrystallization treatment method is based on R ₂ Fe.
₁₄ The English acronyms for the steps of hydrogenation, phase decomposition, dehydrogenation, and recombination of the B-based compound phase are lined up and called the HDDR processing method, and it is true that RT- (M) Anisotropic magnet powder can be obtained by subjecting a -B alloy to HDDR treatment.
Really H. D. D. R. It is the current situation that the mechanism of the anisotropy has not been clarified yet, whether it consists of each process.

[0009] Therefore, many attempts have been made in recent years to optimize the treatment to obtain an R-T-B type alloy powder having excellent characteristics. It is close to the trial and error of conducting and confirming, and the difficulty is investigated without even an index for estimating or judging whether or not the processing condition is optimum.

In view of the current state of the hydrogenation / recrystallization treatment method, the present invention has an object to clarify the mechanism of the anisotropy, and the RT for which the treatment condition is optimized.
-(M) -Aiming to provide a method for producing a B-based alloy powder,
Moreover, it aims at providing what can be an indispensable index in order to optimize such processing conditions.

[0011]

[Means for Solving the Problems] To clarify the mechanism of anisotropy of the alloy in the hydrogenation / recrystallization treatment method, the inventors have made a detailed investigation and earnest study on the hydrogenated alloy structure. As a result of the addition, in the hydrogenated alloy, an intermediate phase (Interm phase) of unknown phase disappears with hydrogenation time.
edit Hydrogenation Phas
e, hereinafter sometimes abbreviated as IH or IH phase).

The intermediate phase newly discovered by the inventors in the alloy in the middle of hydrogenation is the solution of the RT- (M) -B type alloy, which is pulverized into a powder, which is then raised in a vacuum. It can be confirmed by an inspection alloy that has been warmed, hydrogenated by introducing hydrogen, taken out during the hydrogenation treatment, and rapidly cooled.
In the case of B-based alloys, the intermediate structure is Nd with the same orientation as the parent phase.
Coarse α-Fe and F containing ₂ Fe ₁₄ B fine particles and NdH ₂
It was found that in addition to the e ₂ B particles, the lamellar structure composed of α-Fe and NdH _{2, a} large amount of the intermediate stage phase is present, and this intermediate stage phase disappears due to the extension of the hydrogenation time.

Further, the inventors have made a detailed study on such a novel intermediate stage phase.
It has a structure similar to that of Nd ₂ Fe ₁₄ B, and the two have a crystal orientation relationship. It is a tetragonal crystal whose a-axis length is almost the same as that of the Nd ₂ Fe ₁₄ B phase and whose c-axis length is about 1/3. , Nd ₂ Fe ₁₄ B
It was found that it is closely related to the mechanism of fine particle formation and anisotropy, and can be an indispensable index for optimizing the processing conditions of the hydrogenation / recrystallization processing method.

Furthermore, the inventors have found that the intermediate phase is composed of undecomposed regions of Nd ₂ Fe ₁₄ B phase due to hydrogenation and lamellar N.
They are in contact with each other with a dH ₂ + α-Fe mixed structure sandwiched between them, and the intermediate stage phase and the Nd ₂ Fe ₁₄ B phase in the undecomposed region maintain an orientation relationship, but the orientation of each phase of the lamellar structure and the undecomposed region phase It does not matter, and α-Fe and Fe ₂ B on the opposite side of the lamella
And NdH ₂ are contained in the intermediate stage phase, and the intermediate stage phase contains hydrogenated Nd ₂ Fe ₁₄ B phase crystallites having an orientation relationship with the undecomposed region phase. It exists in the frontier part of the cracking reaction, and when the hydrogenation / cracking reaction is completed, the frontier disappears and the intermediate stage phase disappears. We have found that this is a necessary condition for obtaining an anisotropic texture with high magnetization.

Further, the inventors have found that inside the intermediate stage phase,
It was confirmed by a high-resolution transmission electron microscope that a microcrystalline phase of Nd ₂ Fe ₁₄ B structure, which was lattice-matched, was always present and that a spherical NdH ₂ phase was also dispersed. Therefore, it was found that by confirming only the existence of the intermediate stage phase, it is possible to guarantee that the desired intermediate stage organization is formed.

That is, the present inventors have found that the most important step in the production of anisotropic texture is R in the intermediate stage phase.
It was the first step to uniformly disperse the fine crystals of the ₂ Fe ₁₄ B phase, and it was found that these phenomena can be verified by taking out and confirming the intermediate phase, and completed the present invention.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The intermediate phase according to the present invention will be described in detail below, its role will be described in detail, and the essence of the hydrogenation / recrystallization treatment method will be further described. R-Fe
After casting, the -B-based alloy has an R ₂ Fe ₁₄ B phase, an RFe ₄ B ₄ phase (only when the B concentration exceeds 6 at%), an α-Fe phase,
R-rich phase, MB phase (only when M is added), and the like. When this is subjected to homogenizing heat treatment, the volume ratio of the α-Fe phase is reduced, but the phase structure itself does not change.
When the homogenized alloy is kept in a hydrogen atmosphere at about 850 ° C., a phase in which hydrogen is solid-dissolved in the R ₂ Fe ₁₄ B phase appears, but this phase is thermodynamically a metastable phase, and the intermediate stage Transform into a phase.

This intermediate stage phase can be brought to room temperature by quenching a sample of the early hydrogenation in oil,
This is the first discovery made by the inventors. The structure is considered to be tetragonal, the a-axis is the same as R ₂ Fe ₁₄ B, and the c-axis is R ₂ F.
e ₁₄ It is one-third of B phase. The composition is such that the R content is R ₂ F.
e ₁₄ lower than the B phase, the analysis results 3at% from 0.5
Of the degree. On the other hand, Fe + Co is 90% or more. The intermediate stage phase contains R, Fe, Co, B and M, and when its composition is represented by an atomic ratio, R: 0.01
-10%, Fe + Co: 70-99%, M: 0.0
1 to 10%, B: The balance.

This intermediate stage phase has an internally lattice-matched R
Incorporating ₂ Fe ₁₄ B phase microcrystals, in many cases,
It contains several R ₂ Fe ₁₄ B crystallites and spherical RH ₂ crystallites.
The intermediate phase is R, which has not yet been decomposed by hydrogenation
₂ Fe ₁₄ B phase undecomposed region and lamellar RH ₂ + α-Fe
The mixed tissues are in contact with each other. The intermediate stage phase and the R ₂ Fe ₁₄ B phase in the undecomposed region maintain the azimuth relationship, and the c-axis directions coincide with each other. R ₂ Fe ₁₄ B is present inside the lamella structure.
No fine crystals were found, and there is no orientation relationship between each phase of the lamella structure and the R ₂ Fe ₁₄ B phase in the undecomposed region. The intermediate stage phase is in contact with the region composed of α-Fe, Fe ₂ B and RH ₂ on the side opposite to the lamella structure, and the part composed of α-Fe phase and Fe ₂ B phase is the undecomposed region R ₂ containing microcrystalline R ₂ Fe ₁₄ B phase that holds the Fe ₁₄ B phase and orientational relationship.

From these facts, in the reaction in the initial stage of hydrogenation, as the hydrogen diffuses from the alloy surface toward the inside, the R ₂ Fe ₁₄ B phase in which hydrogen is solid-solved is first transformed into the R-rich intermediate stage phase. Conceivable. At this time, a region where the ratio of Co + M element is high is partially formed by thermal fluctuation of the composition,
In that region, R ₂ Fe ₁₄ B microcrystals are left without transformation, R is discharged from the R-rich intermediate stage phase, and RH ₂ is precipitated as spherical particles, and then the intermediate stage phase is α-Fe.
And Fe ₂ B phase.

The intermediate phase exists in the frontier part of the hydrocracking reaction in this way, and is quenched at room temperature by quenching in the hydrogen gas until the entire alloy completes the hydrogenolysis / cracking reaction and observed. can do.

During the Quench process, the boundary between the undecomposed region and the intermediate phase becomes unstable due to the high R content in the intermediate phase and decomposes into a lamellar structure of α-Fe and RH _2. it is conceivable that. Alternatively, as another way of thinking, undecomposed R ₂ Fe ₁₄ close to the frontier of decomposition reaction is used.
Since the hydrogen content of phase B is higher than the equilibrium hydrogen content near room temperature, this part is decomposed during the cooling process and RH
_It is also considered to transform into a lamellar structure of ₂ and α-Fe. When the hydrogenation / cracking reaction is completed, the frontier disappears and the intermediate phase disappears. Complete decomposition of the intermediate phase is a necessary condition for obtaining an anisotropic texture with high coercive force and residual magnetization through the subsequent dehydrogenation step.

Next, the dehydrogenation step is performed. A lower than the equilibrium hydrogen pressure of the RH ₂ the pressure of the hydrogen gas, RH ₂ is releasing hydrogen, a metal R is produced. This state is unstable and immediately reacts with the surrounding phase to form the R ₂ Fe ₁₄ B phase. At this time, R ₂ Fe ₁₄ B finely dispersed in the structure
Since the microcrystals serve as nuclei and the crystal grain growth progresses, a fine texture of R ₂ Fe ₁₄ B having a uniform orientation is formed.

If R ₂ Fe ₁₄ B in the undecomposed region directly decomposes into α-Fe + RH ₂ + Fe ₂ B + R ₂ Fe ₁₄ B without passing through the intermediate stage phase, R ₂ Fe ₁₄ B in the R ₂ Fe ₁₄ B phase before decomposition Since a large compositional variation of constituent elements such as R and B must occur, and there is no mechanism capable of forming a structure in which R ₂ Fe ₁₄ B is left uniformly in the structure,
In the final product, it is not possible to obtain a homogeneous anisotropic texture, resulting in an isotropic texture or an alloy texture with low coercive force and Hk and low properties as an anisotropic magnet.

Therefore, the role of the intermediate stage phase is (1) functioning as a matrix phase which inherits the orientation relation of the original R ₂ Fe ₁₄ B phase as it is. (2) Helps maintain a state in which the R ₂ Fe ₁₄ B microcrystals maintaining the original orientation are uniformly dispersed.

As described in detail above, for example, anisotropic N
The HDDR process as a means for obtaining a d-Fe-B magnetic alloy involves hydrogenation / decomposition and dehydrogenation
Rather than a two-step process of recombination, (1) a step of producing lattice-matched Nd ₂ Fe ₁₄ B crystallites in an intermediate phase,
It consists of three steps: (2) the step of completely decomposing the intermediate phase, and (3) the step of forming a texture composed of innumerable Nd ₂ Fe ₁₄ B crystals having the original orientation after dehydrogenation. I can say. Therefore, it can be said that the most essential step of forming the anisotropic texture is the first step in which fine crystals of the Nd ₂ Fe ₁₄ B phase are uniformly dispersed in the intermediate step phase.

The method of using the intermediate phase will be described below. First, at a very early stage of the hydrogenation / decomposition reaction, a part of the alloy is taken out of the furnace and observed by a scanning electron microscope or the like, so that it is possible to determine whether or not the hydrogenation is performed under correct conditions.

That is, in order to obtain an anisotropic texture, it is essential to form a hydrogenated structure in which R ₂ Fe ₁₄ B crystallites memorizing the original orientation are uniformly dispersed. To observe these crystallites, an acceleration voltage of 300 kV-4
A high-performance transmission electron microscope with high performance of about 00 kV is required, and it cannot be observed unless the orientation of the sample is adjusted such that the c-axis of R ₂ Fe ₁₄ B and the direction of the electron beam are parallel. However, since such R ₂ Fe ₁₄ B crystallites are homogeneously dispersed in the intermediate phase (IH), it is sufficient to confirm the existence of the IH phase. The intermediate phase has a size of several hundreds nm, can be observed with a scanning electron microscope, and it is not necessary to align the orientation. Therefore, the time required for the determination can be significantly reduced.

As a method of utilizing the intermediate stage phase, when the hydrogenation / cracking reaction is completed, the intermediate stage phase is wholly decomposed. Therefore, the presence of the intermediate stage phase in determining the end point of the hydrogenation / cracking reaction step. Can be used.

Hereinafter, various manufacturing methods, adjusting methods, methods and the like using the above-mentioned intermediate stage phase according to the present invention will be described. Hereinafter, an example using Nd for R will be described. First, as a fine structure adjusting method for an alloy for an Nd-T-B type anisotropic magnet having an anisotropic texture, (1) an alloy containing a Nd ₂ Fe ₁₄ B compound as a main phase is heat-treated in a hydrogen atmosphere. , The Nd ₂ Fe ₁₄ B phase contained in the alloy is converted to the original Nd ₂ Fe ₁₄
Same as B phase, with c-axis one-third and original Nd ₂ Fe ₁₄
A tetragonal intermediate phase having the same c-axis direction as the B phase, an undecomposed Nd ₂ Fe ₁₄ B phase, an NdH ₂ phase, and α-F
a step of decomposing into a five-phase mixed structure of e and Fe ₂ B,
(2) Existence in the original alloy by further decomposing the intermediate-stage phase into α-Fe and Fe ₂ B by heat treatment in hydrogen gas, and reducing the volume ratio of the intermediate-stage phase to 5% or less. substantially undegraded Nd ₂ portions of the Nd ₂ Fe ₁₄ B phase
Step of forming a four-phase structure of Fe ₁₄ B, α-Fe, NdH ₂ and Fe ₂ B, (3) Heat treatment with a partial pressure of hydrogen gas reduced to 10 kPa or less, and 95% or more by volume of Nd ₂ Fe ₁₄ There is a manufacturing method including a step of recombining with phase B and a step of (4) cooling to room temperature and taking out into the atmosphere.

Further, in the above-mentioned fine structure adjusting method, in step (1), a matrix containing a large number of undecomposed Nd ₂ Fe ₁₄ B phase fine crystals lattice-matched with the intermediate stage phase is contained in the matrix. There is a manufacturing method characterized by making a microstructure of Specifically, the following a, b
Process. (A) After raising the temperature to 760 ° C. to 870 ° C. at a hydrogen partial pressure of 50 Pa or less, the hydrogen gas pressure is set to 10 kPa to 1000 kPa and kept for 15 minutes to 2 hours. (B) Hydrogen partial pressure of 10 kPa to 500 kPa and 600 ° C to
A temperature range of 750 ° C. is passed at a temperature rising rate of 10 ° C./min to 200 ° C./min, and the temperature is maintained at 760 ° C. to 870 ° C. for 15 to 2 hours.

In the above fine structure adjusting method, the temperature range is 760 ° C to 900 ° C. A production method is also useful in which step (2) is carried out under a hydrogen partial pressure higher than that in step (1) (maximum 100 kPa) under the condition of 15 minutes to 6 hours to promote decomposition of the intermediate phase.

As another method for adjusting the microstructure of an alloy for Nd-T-B system anisotropic magnets, (1) an alloy containing a Nd ₂ Fe ₁₄ B compound as a main phase is heat-treated in hydrogen gas to form an alloy in the alloy. From the included Nd ₂ Fe ₁₄ B phase, the a-axis is the same as the original Nd ₂ Fe ₁₄ B phase, the c-axis is one-third, and the orientation of the c-axis is the same as the original Nd ₂ Fe ₁₄ B phase. Nd ₂ Fe ₁₄ diameter 5nm~100nm lattice is aligned in the tetragonal phase (IH) to B
Step of forming a structure in which phase microcrystals and spherical NdH ₂ are dispersed, (2) heat treatment in hydrogen gas to further decompose the tetragonal phase (IH) into α-Fe and Fe ₂ B, by the volume ratio of the phase (IH) 5% or less, substantially Nd ₂ Fe ₁₄ B microcrystalline portions of the Nd ₂ Fe ₁₄ B phase which is present in the original alloy alpha-Fe and Fe ₂ B
A step of forming a structure consisting of NdH ₂ and finely dispersed parts in the phase, (3) reducing the partial pressure of hydrogen gas to 10 kPa or less and heat-treating, and recombining 95% or more by volume ratio with the Nd ₂ Fe ₁₄ B phase. And a step (4) of cooling to room temperature and taking out into the atmosphere.

Further, as a method for adjusting the microstructure of the alloy for Nd-T-B type anisotropic magnet, (1) an alloy containing a Nd ₂ Fe ₁₄ B compound as a main phase is heat-treated in hydrogen gas, Around the contained Nd ₂ Fe ₁₄ B phase, the a-axis is the original Nd ₂ F
e ₁₄ Same as B phase, with c-axis one-third and original Nd ₂ F
e ₁₄ B phase and tetragonal phase (IH) having the same c-axis direction
Nd ₂ with a diameter of 5 nm to 100 nm in which the lattice is matched
Step of forming a structure in which Fe ₁₄ B phase microcrystals and spherical NdH ₂ are dispersed, (2) Nd ₂ Fe having a diameter of 120 nm or more surrounded by IH phase by heat treatment in hydrogen gas
_{14 A step of making the} B phase region 5% or less of the alloy by volume ratio,
(3) IH is further decomposed into α-Fe and Fe ₂ B by heat treatment in hydrogen gas, and the total volume ratio of IH is set to 5% or less, whereby Nd existing in the original alloy is reduced. _{The 2} Fe ₁₄ B phase portion is substantially Nd ₂ Fe ₁₄ B fine crystal finely dispersed in α-Fe and the Fe ₂ B phase portion and N
Step of forming a structure composed of dH ₂ , (4) Step of heat-treating by reducing hydrogen gas partial pressure to 10 kPa or less, and step of recombining 95% or more by volume ratio with Nd ₂ Fe ₁₄ B phase, (5) Cooling to room temperature However, there is a manufacturing method including a step of taking out into the atmosphere.

When starting the heat treatment step in hydrogen, it is essential that most of the alloy is in the undecomposed Nd ₂ Fe ₁₄ B phase at the starting point in order to finally obtain an anisotropic texture. is there. Therefore, the following precautions are required in the temperature raising process up to the heat treatment temperature. That is, in the temperature range of 600 ° C. to 750 ° C., Nd under a hydrogen gas pressure of 100 Pa or more.
₂ Fe ₁₄ B phase is not stable, and Fe ₂ B, NdH ₂ and α-
It tends to completely decompose into Fe. Therefore, the following two processes can be proposed as a method for raising the temperature in this temperature range without decomposing Nd ₂ Fe ₁₄ B. (1) The hydrogen pressure is set to 50 Pa or less. (In this case, hydrogen gas is introduced into the system after the alloy temperature reaches 760 ° C. or higher.) (2) The heating rate is made sufficiently fast. (At this time, at least 10 ℃
/ Min or more is required. The upper limit is determined by the balance between the facility capacity and the total heat capacity of the alloy, and is usually 200 ° C / mi.
It is difficult and meaningless for n or more. )

Therefore, as a method of adjusting the anisotropic hard magnetic alloy structure to obtain the texture composed of Nd ₂ Fe ₁₄ B microcrystals, the temperature is raised from 760 ° C. to 870 ° C. at a hydrogen partial pressure of 50 Pa or less and then 10 kPa to 800 kPa. After maintaining the hydrogen gas pressure of 15 minutes to 30 hours, a part of the alloy is taken out from the sampling port, and Nd ₂ F contained in the alloy is removed.
e ₁₄ Around the B phase, a cycle of α-Fe and NdH _{2 of} 5
Through the lamella structure having a thickness of 0 nm to 300 nm and a thickness of 100 nm to 2000 nm, the a-axis is the same as the original Nd ₂ Fe ₁₄ B phase, the c-axis is 1/3, and the original Nd ₂ Fe ₁₄ B phase and c It was confirmed that Nd ₂ Fe ₁₄ B phase microcrystals having a diameter of 5 nm to 100 nm and lattice-matched with a tetragonal phase (IH) having the same axis direction and spherical NdH ₂ were dispersed. After that, the hydrogen partial pressure is reduced to 10 kPa or less to separate hydrogen gas from the alloy, and the diameter is 0.05 μm to 1 μm.
There is a method of obtaining a texture composed of Nd ₂ Fe ₁₄ B microcrystals of m.

Further, as a method of adjusting the anisotropic hard magnetic alloy structure to obtain a texture composed of another Nd ₂ Fe ₁₄ B microcrystal, a hydrogen partial pressure of 10 kPa to 500 kPa and 600 ° C.
After passing through the temperature range of 750 ° C to 750 ° C at a temperature rising rate of 10 ° C / min to 200 ° C / min and holding at 760 ° C to 870 ° C for 15 to 60 minutes, a part of the alloy is taken out from the sampling port and Around the Nd ₂ Fe ₁₄ B phase contained in
Through the lamellar structure of the periodic 50nm~300nm thickness 100nm~2000nm consisting -Fe and NdH _2, a
The axis is the same as the original Nd ₂ Fe ₁₄ B phase and the c axis is 1/3
And a diameter of 5 nm in which the lattice is matched with the original Nd ₂ Fe ₁₄ B phase and the tetragonal phase (IH) having the same c-axis direction.
˜100 nm Nd ₂ Fe ₁₄ B phase crystallites and spherical NdH ₂
After confirming that and have a dispersed structure, the hydrogen partial pressure is lowered to 10 kPa or less to separate hydrogen gas from the alloy, and an aggregate consisting of Nd ₂ Fe ₁₄ B microcrystals with a diameter of 0.05 μm to ₁ μm. There is a way to get an organization.

In the method for producing the R-T-B type anisotropic magnet alloy powder of the present invention, the composition of the alloy containing the R ₂ Fe ₁₄ B compound as the main phase is R: 10 to 20 at%, T:
67 to 85 at%, B: 4 to 10 at%, M: 10 at
Alloys whose main component is not more than% are preferable. R used in the raw material alloy used in the present invention, that is, the rare earth element is Y, L
a, Ce, Pr, Nd, Sm, Gd, Tb, Dy, H
O, Er, Tm, and Lu are included, and at least one of them is included, and at least one of Pr and Nd or 2 is included.
It is necessary to contain 50 at% or more of R in seeds. The reason why 50 at% or more of R is 1 type or 2 types of Pr and Nd is that sufficient magnetization cannot be obtained at less than 50 at%.

When R is less than 10 at%, the coercive force is lowered due to precipitation of α-Fe phase, and when it exceeds 20 at%,
In addition to the intended tetragonal Nd ₂ Fe ₁₄ B type compound, a large amount of R-rich second phase precipitates, and if the amount of this second phase is too large, the alloy magnetization decreases. Therefore, the range of R is 10 to 20 at
%

T is an iron group element and includes Fe and Co. If T is less than 67 at%, the second coercive force and low magnetization precipitates and the magnetic properties are deteriorated. If it exceeds 85 at%, the coercive force and squareness are deteriorated due to the precipitation of the α-Fe phase. , 67 to 85 at%. Further, although necessary magnetic properties can be obtained with Fe alone, addition of Co is useful for improving the Curie temperature, that is, improving heat resistance, and can be added as necessary. In the atomic ratio of Fe and Co, F
When e is 50% or less, the amount of decrease in the saturation magnetization of the Nd ₂ Fe ₁₄ B type compound itself becomes large, so that Fe in the atomic ratio of T is set to 50% or more.

B is essential for stably depositing a tetragonal Nd ₂ Fe ₁₄ B type crystal structure. Addition amount is 4
When it is at% or less, the R ₂ T ₁₇ phase precipitates to lower the coercive force, and the squareness of the demagnetization curve is significantly impaired. Also,
When added in excess of 10 at%, the second magnetization is small.
The phase precipitates and reduces the magnetization of the powder. Therefore, B is
It was set to 4 to 10 at%.

Further, as other additive elements, in order to make them anisotropic for the purpose of improving the magnetic properties even after the hydrogenation / recrystallization treatment, the decomposition reaction of the mother phase is not completely completed during the hydrogenation. However, an element effective for stabilizing the parent phase, that is, the R ₂ T ₁₄ B phase and intentionally remaining is desired. Al, Ti, V, Cr, Ni, and G have particularly remarkable effects.
a, Zr, Nb, Mo, In, Sn, Hf, Ta, W. The additive element may not be added at all, but if it exceeds 10 at%, the second phase that is not ferromagnetic precipitates to lower the magnetization, so the additive amount is 10 at%.
The following is assumed.

In the present invention, as a method of obtaining the intermediate stage phase, quenching in room temperature can be performed by quenching in the hydrogen gas until the entire alloy completes the hydrogenation / decomposition reaction, and it can be observed. As the quenching method and preferable conditions, (a) a method of quenching a part of the alloy (preferably 10 g or less in weight) into oil at 10 ° C to 60 ° C while keeping the hydrogen gas pressure the same as during hydrogenation , (B) a method of transferring a part of the alloy to another chamber and then rapidly cooling it in a hydrogen gas jet, and (c) a method of transferring a part of the alloy to another chamber and then rapidly cooling it in a helium gas jet. ,
and so on. The cooling rate at this time is 10 ° C / min or more,
It is preferably 100 ° C./min or more.

[0044]

【Example】

Example 1 An Nd ₁₃ Fe _62.2 Co _10.8 B _8.9 Ga ₁ Zr _0.1 alloy was solutionized and then pulverized to obtain coarsely pulverized powder. 1 Pa of this powder
After heating to 850 ° C. in the following vacuum, the purity is 99.999.
In an H ₂ atmosphere of 100 kPa in which 9% or more of H ₂ gas was introduced, hydrogenation was carried out for various times, and the sample taken out was quenched in oil to be rapidly cooled to room temperature to obtain an inspection alloy.
The obtained alloy was processed to a thickness that allows the electron beam to pass therethrough, and observed with a transmission electron microscope at an acceleration voltage of 300 kv to 400 kv.

FIG. 1 shows a schematic diagram of the results of observation by a transmission electron microscope of the sample obtained as described above. In the sample hydrogenated for 30 to 60 minutes, Nd ₂ Fe ₁₄ B fine particles having the same orientation as the residual Nd ₂ Fe ₁₄ B phase (mother phase) and coarse α-containing NdH ₂ were formed.
It was found that in addition to the Fe and Fe ₂ B particles and the lamellar structure composed of α-Fe and NdH _{2, a} large amount of unknown phase remained. It was also found that this unknown phase disappears as the hydrogenation time increases. Therefore, this unknown phase is referred to as an intermediate phase (IH: Intermediate Hydrogen).
application phase).

FIG. 2 is a photograph of an electron diffraction image from the intermediate phase (IH) and the residual matrix of the test alloy of Example 1,
The case where an electron beam is incident parallel to the c-axis direction of the mother alloy is shown. The intermediate phase has a structure similar to Nd ₂ Fe ₁₄ B,
It can be seen that the two have a crystal orientation relationship.

FIG. 3 shows a photograph of an electron beam diffraction image when an electron beam is incident perpendicularly to the c-axis direction of the mother alloy, where A is the residual Nd ₂ Fe ₁₄ B microcrystal and B is the intermediate stage phase. Show. From FIG. 3, the period of the diffraction spot in the C-axis direction, in the intermediate stage phase are tripled Nd ₂ Fe ₁₄ B phase, the length of the c axis of the intermediate stage phase in the real space is Nd ₂ Fe ₁₄ B One third of the phase
It turns out that it is. From these, it is judged that the structure of IH is a tetragonal crystal whose a-axis length is almost the same as Nd ₂ Fe ₁₄ B and whose c-axis length is about 1/3. In the figure, the a-axis length seems to be different due to the difference in the extinction rules of the two diffractions.

FIG. 4 shows the test alloy of Example 1,
3 is an ultra-high resolution transmission electron micrograph showing Nd ₂ Fe ₁₄ B crystallites present in the intermediate phase. From FIG. 4, it can be seen that the lattices of the two phases are matched.

FIG. 5 shows the inspection alloy of Example 1,
Α-Fe after decomposition of the intermediate phase into α-Fe and Fe ₂ B
It is an ultrahigh-resolution transmission electron micrograph showing Nd ₂ Fe ₁₄ B microcrystals present in Fe. In addition, Nd ₂ Fe ₁₄ B
An electron diffraction image photograph of the microcrystal is also shown in the image.

FIG. 6 shows the inspection alloy of Example 1,
F after the intermediate phase has decomposed into α-Fe and Fe ₂ B
It is an ultra-high resolution transmission electron micrograph showing Nd ₂ Fe ₁₄ B microcrystals present in e ₂ B. In addition, an electron diffraction image photograph of Nd ₂ Fe ₁₄ B microcrystals existing in Fe ₂ B is also shown.

FIG. 7 is an ultra-high resolution transmission electron micrograph showing a part of the structure of the inspection alloy of Example 1. Most of the background is the intermediate phase (IH), the lamellar structure (l) and α-Fe (f) on the left side of the photograph, and spherical NdH ₂ (n having a diameter of 100 to 200 nm dispersed in the intermediate phase).
h) and residual Nd ₂ Fe ₁₄ B microcrystals (nf) of several nm are observed. It should be noted that FIG. 6 is a photograph of only the decomposed portion of the alloy structure, so that undecomposed Nd ₂ Fe
₁₄ Phase B (mother phase) is not shown.

From the above results, it is considered that the structure of the intermediate phase is tetragonal, the a-axis is the same as Nd ₂ Fe ₁₄ B, and the c-axis is N.
It is one third of the d ₂ Fe ₁₄ B phase. As for the composition, the Nd content is lower than that of the Nd ₂ Fe ₁₄ B phase, and the analysis result is about 0.5 to 3 at%. On the other hand, Fe + Co is 90
% Or more. However, since B has not been analyzed, the percentage is not correct.

Example 2 Composition No. 1 of Table 1 obtained by melting by the high frequency induction melting method. The ingots 1 to 4 were annealed at 1100 ° C. for 24 hours in an Ar atmosphere, and the ingots were roughly pulverized to 300 μm or less. The coarsely pulverized powder was placed in a pressure vessel and evacuated to 1 Pa or less. After that, hydrogen gas having a purity of 99.999% or more was introduced to make the internal pressure of the container 50 HPa or less and the temperature was raised to 760 ° C to 870 ° C, and then 10 kPa to
After setting the hydrogen gas pressure to 800 kPa and holding it for 15 to 30 minutes, a part of the alloy was taken out from the sampling port, quenched in oil, and rapidly cooled to obtain an alloy for inspection. The obtained alloy was examined using a scanning electron microscope with an EDX function.

Around the Nd ₂ Fe ₁₄ B phase contained in the inspection alloy, a period of 50 nm consisting of α-Fe and NdH ₂
A wide range of Nd-F containing Nd of 10 at% or less through a lamellar structure having a thickness of 300 nm and a thickness of 100 nm to 2000 nm.
Since there is an e-Co-Ga phase (B cannot be distinguished by this method), and the Fe-Co alloy phase and a large amount of light elements are contained on the side opposite to the lamella structure, it is distinguished as the Fe ₂ B phase. It was confirmed that the structure has particles (300 nm to 800 nm) with a phase.

Then, the hydrogen partial pressure is lowered to 10 kPa or less to separate hydrogen gas from the alloy, and the diameter is 0.05 μm to 1 μm.
An anisotropic hard magnetic alloy structure was obtained to obtain a texture composed of Nd ₂ Fe ₁₄ B microcrystals of μm.

Example 3 Composition No. 1 of Table 1 obtained by melting by the high frequency induction melting method. The ingot 1 was annealed at 1100 ° C. for 24 hours in an Ar atmosphere, and the ingot was roughly pulverized to 300 μm or less. The coarsely pulverized powder was placed in a pressure vessel and evacuated to 1 Pa or less. After that, hydrogen gas having a purity of 99.999% or more was introduced to adjust the pressure in the container to a hydrogen partial pressure of 130 kPa.
After passing through the temperature range of 00 ° C to 750 ° C at a temperature rising rate of 20 ° C / min and holding at 850 ° C for 30 minutes, it was taken out from the sampling port and rapidly cooled to obtain an inspection alloy.
The obtained alloy was examined by a scanning electron microscope with an EDX function.

Around the Nd ₂ Fe ₁₄ B phase contained in the inspection alloy, a period of 50 nm consisting of α-Fe and NdH ₂
A wide range of Nd-F containing Nd of 10 at% or less through a lamellar structure having a thickness of 300 nm and a thickness of 100 nm to 2000 nm.
Since there is an e-Co-Ga phase (B cannot be distinguished by this method), and the Fe-Co alloy phase and a large amount of light elements are contained on the side opposite to the lamella structure, it is distinguished as the Fe ₂ B phase. It was confirmed that the structure has particles (300 nm to 800 nm) with a phase.

Then, the hydrogen partial pressure is reduced to 10 kPa or less to separate hydrogen gas from the alloy, and the diameter is 0.05 μm to 1 μm.
A texture composed of Nd ₂ Fe ₁₄ B crystallites of μm was obtained.

Example 4 Composition No. of Table 1 obtained by melting by high frequency induction melting method The ingot No. 4 was annealed at 1100 ° C. for 24 hours in an Ar atmosphere, and the ingot was roughly pulverized to 300 μm or less. The coarsely pulverized powder was placed in a pressure vessel and evacuated to 1 Pa or less. After that, hydrogen gas having a purity of 99.999% or more was introduced so that the pressure in the container was set to 50 Pa or less for the hydrogen partial pressure. As a result, the structure is a tetragonal structure in which the a-axis is the same as the original Nd ₂ Fe ₁₄ B phase, the c-axis is 1/3, and the original Nd ₂ Fe ₁₄ B phase has the same c-axis orientation. Intermediate phase (IH) and undecomposed Nd ₂ Fe ₁₄ B
Phase, NdH ₂ phase, α-Fe, and Fe ₂ B were decomposed into a five-phase mixed structure. (A microstructure was obtained in which the intermediate-stage phase was a matrix containing a large number of undecomposed Nd ₂ Fe ₁₄ B-phase crystallites lattice-matched with it.

Then, a hydrogen partial pressure higher than that in the above step is set to 180.
The temperature was maintained at 850 ° C. to 875 ° C. for 2 hours at kPa. As a result, the intermediate stage phase was further converted to α-Fe and Fe ₂ B.
And Nd ₂ Fe ₁₄ B phase portion existing in the original alloy is substantially undecomposed Nd ₂ Fe ₁₄ B and α-Fe and NdH. ₂ and F
A four-phase structure with e ₂ B was obtained.

Further, the partial pressure of hydrogen gas was reduced to 10 kPa or less and heat treatment was performed under the condition of 825 ° C. × 1 hour, and then,
When cooled to room temperature under the condition of an average cooling rate of 13 ° C./min and taken out into the atmosphere, 95% or more by volume ratio was recombined with the Nd ₂ Fe ₁₄ B phase.

Example 5 Composition No. 1 of Table 1 obtained by melting by the high frequency induction melting method. The ingot No. 4 was annealed at 1100 ° C. for 24 hours in an Ar atmosphere. This ingot was put in a pressure vessel and evacuated to 1 Pa or less. Then, hydrogen gas having a purity of 99.999% or higher was introduced to adjust the pressure in the container to 200 kPa, and the temperature was kept at 100 ° C. for 10 hours. The obtained coarsely pulverized powder is heated to 600 ° C. to 7 ° C. under a hydrogen partial pressure of 90 kPa in the container.
Pass the temperature range of 50 ° C at a temperature rising rate of 15 ° C / min,
Hold at 830 ° C for 45 minutes. As a result, the structure has a lattice matching diameter of 5 nm to 10 nm with the intermediate phase of the tetragonal phase.
It had a structure in which Nd ₂ Fe ₁₄ B phase fine crystals of 0 nm and spherical NdH ₂ were dispersed.

Then, the hydrogen partial pressure is higher than that in the above step 150.
It was kept at a temperature range of 825 ° C to 850 ° C in kPa for 3 hours. As a result, the intermediate phase is decomposed into α-Fe and Fe ₂ B to have a volume ratio of 5% or less, and the portion of the Nd ₂ Fe ₁₄ B phase existing in the original alloy is substantially Nd ₂ Fe. _The structure was that in which ₁₄ B microcrystals were finely dispersed in α-Fe and Fe ₂ B phase and NdH ₂ .

Further, the partial pressure of hydrogen gas was reduced to 10 kPa or less and heat treatment was performed under the conditions of 825 ° C. to 850 ° C., after which it was cooled to room temperature under the condition of an average cooling rate of 5 ° C./min and taken out into the atmosphere. However, 95% or more by volume ratio was recombined with the Nd ₂ Fe ₁₄ B phase.

Example 6 Composition No. 1 in Table 1 obtained by melting by the high frequency induction melting method. The ingot No. 4 was annealed at 1100 ° C. for 24 hours in an Ar atmosphere. This ingot was put in a pressure vessel and evacuated to 1 Pa or less. Then, hydrogen gas having a purity of 99.999% or higher was introduced to adjust the pressure in the container to 200 kPa, and the temperature was kept at 100 ° C. for 10 hours. The alloy collapsed due to hydrogen occlusion and was coarsely crushed. The obtained coarsely pulverized powder is heated to 825 ° C. under a pressure of hydrogen in the container of 10 Pa or less, and is then heated to 825 ° C. to have a hydrogen gas partial pressure of 80 kPa for 20 minutes to 40 minutes.
Minutes. As a result, Nd ₂ Fe ₁₄ contained in the alloy
Around the B phase, Nd ₂ Fe ₁₄ B having a diameter of 5 nm to 100 nm and having a lattice matched with the intermediate phase (IH) of the tetragonal phase.
A structure in which phase crystallites and spherical NdH ₂ were dispersed was obtained.

Then, the hydrogen partial pressure is 120 kPa and 850 ° C.
By holding it for 90 minutes, the region of the Nd ₂ Fe ₁₄ B phase surrounded by the intermediate stage phase and having a diameter of 120 nm or more was reduced to 5% or less of the alloy by volume ratio.

Further, the hydrogen gas partial pressure is set to 200 kPa or less, the temperature range is 860 ° C. to 880 ° C., and the heat treatment is performed for 1 hour. Then, the atmosphere is cooled to room temperature under the conditions of Ar gas 2 atm and fan cooling. When taken out, 95% or more by volume ratio was recombined with the Nd ₂ Fe ₁₄ B phase.

[0068]

[Table 1]

[0069]

Industrial Applicability According to the present invention, after the RT- (M) -B alloy is made into a coarse powder, the temperature is raised in a vacuum, hydrogen is introduced and hydrogenated, and it is taken out during the hydrogenation treatment and rapidly cooled. The intermediate phase that can be confirmed from this inspection alloy is the coarse α-Fe and Fe ₂ B particles containing R ₂ Fe ₁₄ B fine particles and RH ₂ having the same orientation as the parent phase, α- In addition to the lamellar structure composed of Fe and RH _{2, a} large amount of Fe-rich alloy phase with R of 10 at% or less is present, and this Fe-rich alloy phase disappears due to extension of hydrogenation time.
During the hydrogenation of the target alloy powder, the Fe-rich alloy phase, that is, the inspection alloy having the intermediate stage phase is taken out to verify the generation and anisotropic processes of R ₂ Fe ₁₄ B fine particles. Adjust to a proper alloy phase structure, that is, set the optimum conditions and perform hydrogenation to R
It is possible to uniformly disperse the fine crystals of the ₂ Fe ₁₄ B phase, and it is possible to obtain an anisotropic texture with high coercive force and residual magnetization after dehydrogenation.

[Brief description of drawings]

FIG. 1 is a schematic view of a transmission electron microscope observation result of an inspection alloy according to the present invention.

FIG. 2 (I in the intermediate phase of the test alloy according to the invention)
3B is an electron diffraction image photograph of Hd) and Nd ₂ Fe ₁₄ B microcrystals remaining therein.

FIG. 3 shows an electron beam diffraction image photograph when an electron beam is incident perpendicularly to the c-axis direction of the master alloy, and A is residual Nd ₂ Fe ₁₄ B
Microcrystal, B indicates an intermediate phase.

FIG. 4 is an ultra high resolution transmission electron micrograph of residual Nd ₂ Fe ₁₄ B crystallites in the intermediate phase of the test alloy according to the present invention.

FIG. 5: Ultra-high resolution transmission electron micrograph and electron beam diffraction image showing Nd ₂ Fe ₁₄ B microcrystals present in α-Fe after the intermediate phase has decomposed into α-Fe and Fe ₂ B. It is a photograph.

FIG. 6 is an ultra-high-resolution transmission electron micrograph and electron diffraction image photograph showing Nd ₂ Fe ₁₄ B microcrystals present in Fe ₂ B after the intermediate phase is decomposed into α-Fe and Fe ₂ B. Is.

FIG. 7 is a transmission electron micrograph of the alloy for inspection at the initial stage of hydrogenation / decomposition reaction.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01F 1/06 H01F 1/06 A (72) Inventor Hiroyuki Tomizawa 2-chome, Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture No. 15-17 Sumitomo Special Metals Co., Ltd. Yamazaki Works (72) Inventor Takashi Ikegami 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture Sumitomo Special Metal Co., Ltd. Yamazaki Works (72) Inventor Toshiro Tomita Osaka, Osaka Sumitomo Metal Industries, Ltd. 4-53-3 Kitahama, Chuo-ku, Tokyo (72) Inventor Naoyuki Sano 4-53-3 Kitahama, Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Sumitomo Metal Industries, Ltd.

Claims (8)

[Claims] 1. A method for producing an alloy powder for an R-T-B type anisotropic magnet having an anisotropic texture, which comprises the following steps. (1) An alloy containing a R ₂ Fe ₁₄ B compound as a main phase is heat-treated in a hydrogen atmosphere to remove the R ₂ Fe ₁₄ B phase contained in the alloy.
a tetragonal crystal (intermediate stage phase IH) in which the a-axis is the same as the original R ₂ Fe ₁₄ B phase, the c-axis is one-third, and has the same c-axis orientation as the original R ₂ Fe ₁₄ B phase , A step of decomposing into an undecomposed R ₂ Fe ₁₄ B phase, a RH ₂ phase, a 5-phase mixed structure of α-Fe and Fe ₂ B, (2) further heat treatment in hydrogen gas to further increase IH Decompose into α-Fe and Fe ₂ B,
By adjusting the volume ratio of H to 5% or less, the portion of the R ₂ Fe ₁₄ B phase existing in the original alloy is substantially undecomposed R ₂
A step of forming a four-phase structure of Fe ₁₄ B, α-Fe, RH ₂ and Fe ₂ B, (3) a hydrogen gas partial pressure is reduced to 10 kPa or less and heat treatment is performed, and 95% or more by volume of R ₂ Fe _{14 is} added. Step of recombining with phase B, (4) Step of cooling to room temperature and taking out to the atmosphere. 2. A method for producing an alloy powder for an R-T-B type anisotropic magnet having an anisotropic texture, which comprises the following steps. (1) An alloy containing a R ₂ Fe ₁₄ B compound as a main phase is heat-treated in hydrogen gas, and the R ₂ Fe ₁₄ B phase contained in the alloy is
The a-axis is the same as the original R ₂ Fe ₁₄ B phase and the c-axis is 1/3
And a tetragonal phase (intermediate phase IH) having the same c-axis direction as the original R ₂ Fe ₁₄ B phase and an R ₂ Fe ₁₄ B phase microcrystal with a diameter of 5 nm to 100 nm and spherical R
A step of forming a structure in which H ₂ is dispersed, (2) IH is further decomposed into α-Fe and Fe ₂ B by heat treatment in hydrogen gas, and the volume ratio of IH is set to 5% or less. The R ₂ Fe ₁₄ B phase portion existing in the original alloy is composed of RH ₂ and a portion in which R ₂ Fe ₁₄ B crystallites are finely dispersed in α-Fe and Fe ₂ B phase. Process,
(3) A step of reducing the partial pressure of hydrogen gas to 10 kPa or less and heat-treating, and recombining 95% or more by volume ratio with the R ₂ Fe ₁₄ B phase, (4) a step of cooling to room temperature and extracting to the atmosphere. 3. A method for producing an RTB-based anisotropic magnet alloy powder having an anisotropic texture, comprising the steps of: (1) An alloy having a R ₂ Fe ₁₄ B compound as a main phase is heat-treated in hydrogen gas, and the R ₂ Fe ₁₄ B phase contained in the alloy is surrounded by the original R ₂ Fe ₁₄ B phase. Same as the above, the c-axis is one-third, and the lattice is matched in the tetragonal phase (IH) having the same R-axis direction as the original R ₂ Fe ₁₄ B phase.
A step of forming a structure in which 100 nm of R ₂ Fe ₁₄ B phase fine crystals and spherical RH ₂ are dispersed, (2) R ₂ Fe ₁₄ having a diameter of 120 nm or more surrounded by IH phase by heat treatment in hydrogen gas A step of reducing the volume of the B phase region to 5% or less of the alloy, (3) by heat treatment in hydrogen gas, I
By further decomposing H into α-Fe and Fe ₂ B and setting the volume ratio of IH to 5% or less in total, the R ₂ Fe ₁₄ B phase portion existing in the original alloy is substantially reduced. R ₂ Fe ₁₄
A step of forming a structure composed of RH ₂ and a portion in which B microcrystals are finely dispersed in α-Fe and Fe ₂ B phase, (4) Heat treatment is performed by reducing the hydrogen gas partial pressure to 10 kPa or less, and the volume ratio is 95%.
% Or more of the R ₂ Fe ₁₄ B phase to be recombined, (5) a step of cooling to room temperature and taking out into the atmosphere. 4. An alloy containing a R ₂ Fe ₁₄ B compound as a main phase is heated to 760 ° C. to 870 ° C. at a hydrogen partial pressure of 50 Pa or less and then at a hydrogen gas pressure of 10 kPa to 800 kPa for 15 minutes to 30 hours. After the holding, a part of the alloy was taken out from the sampling port, rapidly cooled to room temperature, and surrounded by the R ₂ Fe ₁₄ B phase contained in the alloy, a cycle of α-Fe and RH _{2 of} 50 nm to 300 nm, thickness of 100 nm to 2000
The Fe-rich intermediate-stage phase (IH) having an R concentration of 10 at% or less exists through the lamella structure of nm, and a region composed of α-Fe and Fe ₂ B phase exists outside thereof. After confirming that the hydrogen partial pressure is 10 kPa
Hydrogen gas is separated from the alloy by lowering it to a diameter of 0.0
A method for producing an alloy powder for an R-T-B anisotropic magnet, which has an anisotropic texture composed of R ₂ Fe ₁₄ B microcrystals of 5 μm to 1 μm. 5. R_TwoFe₁₄Alloy containing B compound as main phase
At a hydrogen partial pressure of 10 kPa to 500 kPa at 600 ° C to 7
Temperature rising rate of 50 ° C over 10 ° C / min to 200 ° C / min
And keep it at 760 ℃ -870 ℃ for 15-120 minutes.
After holding, take out a part of the alloy from the sampling port
And then rapidly cooled to room temperature, R contained in the alloy _TwoFe₁₄Phase B
Around α-Fe and RH_TwoA period of 50 nm to 30
0 nm thickness 100 nm-2000 nm through lamella structure
And Fe-rich intermediate-stage phase with R concentration of 10 at% or less
(IH) exists, and α-Fe and Fe are further present outside thereof._Two
Textured RH with a region consisting of phase B_TwoAnd are dispersed
After confirming that the structure is
Reduced to below kPa to separate hydrogen gas from the alloy,
R of 0.05 μm to 1 μm_TwoFe₁₄Difference consisting of B crystallites
Alloy powder for R-T-B anisotropic magnets having an anisotropic texture
Manufacturing method of powder. 6. The IH phase according to any one of claims 1 to 5, wherein the IH phase contains R, Fe, Co, B and M, and when its composition is represented by an atomic ratio, R: 0.01 to 10%, Fe + Co:
70 to 99%, M: 0.01 to 10%, B: a method for producing an R-T-B based alloy powder for anisotropic magnets having the remaining anisotropic texture. 7. An alloy containing a R ₂ Fe ₁₄ B compound as a main phase is heated to 760 ° C. to 870 ° C. at a hydrogen partial pressure of 50 Pa or less and then set to a hydrogen gas pressure of 10 kPa to 800 kPa for 15 to 60 minutes. After holding, a part of the alloy was taken out from the sampling port and rapidly cooled to room temperature. 8. An alloy containing a R ₂ Fe ₁₄ B compound as a main phase is prepared at a hydrogen partial pressure of 10 kPa to 500 kPa at 600 ° C. to 7 ° C.
After passing through the temperature range of 50 ° C at a temperature rising rate of 10 ° C / min to 200 ° C / min and holding at 760 ° C to 870 ° C for 15 to 60 minutes, a part of the alloy is taken out from the sampling port and rapidly cooled to room temperature. Inspection alloy.