JP2007005786A - Rare-earth magnet powder and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide rare-earth magnet power having been subjected to high-temperature hydrogen heat treatment and having high anisotropy, and a method for manufacturing the same. <P>SOLUTION: The rare-earth magnet power having been subjected to high-temperature hydrogen heat treatment has a composition of a rare-earth element (R) including yttrium (Y) of 11 to 15 at%, B of 5 to 8 at%, one or two kinds of Ga and Nb of 0.01 to 1.0 at%, respectively, and Fe and unavoidable impurities as the rest. The rare-earth magnet power having been subjected to high-temperature hydrogen heat treatment has a composition of R of 11 to 15 at%, B of 5 to 8 at%, Co of 25 at% or less, one or two kinds of Ga and Nb of 0.01 to 1.0 at%, respectively, and Fe and unavoidable impurities as the rest. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rare earth magnet powder having excellent magnetic properties and a method for producing the same.

  In recent years, permanent magnets are required to have higher performance. Rare earth magnets have been actively developed as permanent magnets that meet this demand.

  Japanese Patent Laid-Open No. 62-23903 discloses a coercive force (iHc) of 398 kA by high-temperature hydrogen heat treatment in which an RFeB alloy is subjected to forward transformation of the structure by occlusion of hydrogen, pulverized, and then reverse transformed to desorb hydrogen. A method for producing a permanent magnet as high as / m (5 kOe) is disclosed. Here, high-temperature hydrogen heat treatment refers to heat treatment that involves structural transformation, and is distinguished from low-temperature hydrogen thermal treatment that involves only occlusion and dehydrogenation of hydrogen that does not involve structural transformation.

Japanese Patent Laid-Open No. 7-68561 discloses an ingot or powder of an alloy mainly composed of a rare earth element (R) containing Y, iron (Fe), and boron (B), with a hydrogen gas pressure of 10 Torr ( 0.013 atm) or higher or a forward transformation in which hydrogen is occluded in the alloy by holding the alloy at 500 to 1000 ° C. or higher in a mixed atmosphere of hydrogen gas and inert gas having a hydrogen gas partial pressure of 10 Torr or higher, Method for producing RFeB alloy magnet powder to be cooled by high-temperature hydrogen heat treatment after reverse transformation in which dehydrogenation treatment is performed at 500 to 1000 ° C. until a vacuum atmosphere with a hydrogen gas pressure of 1 × 10 ⁻¹ Torr or less is continuously obtained Is disclosed.

  Further, a part of Fe of this RFeB-based alloy magnet is one kind of metal such as Co, Ni, V, Nb, Ta, Cu, Cr, Mn, Mo, W, Ti, Al, Ga, In, Zr, and Hf. Alternatively, two or more small amounts may be substituted, and examples of this substitution include those obtained by substituting a small amount of one of Co, Pr, and Dy. However, the above publication does not show improvement in magnetic properties by substitution of these metal elements.

  Japanese Patent Application Laid-Open No. 3-129702 discloses that R, Fe, and B are the main components, Ti, V, Nb, Ta, Al, Si, Ga, Zr, and Hf are added, and the magnet characteristics are improved by high-temperature hydrogen treatment. An anisotropic permanent magnet powder is disclosed.

  Further, in JP-A-3-129703, as described above, R, Fe, Co, and B are the main components, and Ti, V, Nb, Ta, Al, Si, Ga, Zr, and Hf are added. Anisotropic permanent magnet powders that improve magnet properties by hydrogen treatment have been disclosed.

  However, the above publication does not improve the anisotropy to a sufficient height.

  Conventionally, anisotropy has been increased by using a large amount of alloying elements exclusively increasing the anisotropy, and the magnetic properties of the main phase of the magnet powder were originally impaired. As a result, high magnetic properties could not be obtained.

  In addition, the residual magnetic flux density, coercive force, etc. are achieved by refining the crystal grains by high-temperature hydrogen heat treatment that performs forward transformation of the structure by hydrogen storage and reverse transformation of the structure by dehydrogenation, which is also a feature of rare earth magnets as a hydrogen storage alloy. The method of obtaining a rare earth magnet powder by high-temperature hydrogen heat treatment that enhances the magnetic properties of the magnet has the advantage that the operation is relatively simple and the production cost is low, but there is a problem that a rare earth magnet powder having excellent magnetic properties cannot be obtained. In particular, it is very difficult to impart anisotropy.

  The present invention provides a rare earth magnet powder that has been subjected to high-temperature hydrogen heat treatment and has a high anisotropy, that is, a high anisotropy with Br / Bs of 0.65 or more, and a method for producing the same. Is an issue.

  The first invention is an anisotropic rare earth magnet powder having an anisotropy of 0.65 or more that has been subjected to a high-temperature hydrogen heat treatment, 11 to 15 at% R, 5 to 8 at% B, 0.01 to It is a rare earth magnet powder having a composition composed of one or two of 1.0 at% of Ga and Nb, and the balance of Fe and inevitable impurities.

  The rare earth magnet powder controls the reaction rate of the forward transformation reaction for occluding hydrogen to 0.25 to 0.50, and the reaction rate of the reverse transformation reaction for releasing hydrogen after the reaction to 0.1 to 0.4. Anisotropy is imparted by high-temperature hydrogen heat treatment to control and cause reaction.

  The second invention is an anisotropic rare earth magnet powder having an anisotropy of 0.65 or more which has been subjected to a high-temperature hydrogen heat treatment, 11 to 15 at% R, 5 to 8 at% B, and 25 at% or less Co. And a rare earth magnet powder having a composition composed of one or two of 0.01 to 1.0 at% of Ga and Nb, and the balance of Fe and inevitable impurities.

  The rare earth magnet powder controls the reaction rate of the forward transformation reaction for occluding hydrogen to 0.25 to 0.50, and the reaction rate of the reverse transformation reaction for releasing hydrogen after the reaction to 0.1 to 0.4. Anisotropy is imparted by high-temperature hydrogen heat treatment to control and cause reaction.

  The third invention is an anisotropic rare earth magnet powder having an anisotropy of 0.65 or more which has been subjected to a high-temperature hydrogen heat treatment, 11 to 15 at% R, 5 to 8 at% B and 25 at% or less Co. The total of one or two of 0.01 to 1.0 at% of Ga and Nb and one or two of Zr, V, Mn, Ni, Cr, Cu, Al, Si, and Mo is 0. It is a rare earth magnet powder having a composition composed of 0.01 to 3.0 at%, and the balance of Fe and inevitable impurities.

  The rare earth magnet powder controls the reaction rate of the forward transformation reaction for occluding hydrogen to 0.25 to 0.50, and the reaction rate of the reverse transformation reaction for releasing hydrogen after the reaction to 0.1 to 0.4. Anisotropy is imparted by a high-temperature hydrogen heat treatment that controls and causes the reaction.

  The anisotropic rare earth magnet powder of the present invention is a rare earth magnet powder having an anisotropy (Br / Bs, where Bs is 1.6T (16 kG)) of 0.65 or more. By using this anisotropic rare earth magnet powder, an anisotropic bonded magnet having a high (BH) max can be obtained.

  In the present invention, it was studied to impart anisotropy to the RFeB-based composition without adding an alloy as much as possible. As a result, an anisotropic rare earth magnet powder having excellent magnetic properties was obtained by high-temperature hydrogen heat treatment that was adapted to the composition of the additive element with a magnet composition with minimal addition of alloying elements.

  The definition of anisotropy in the present invention is that anisotropy Br / Bs (Bs is 1.6 T (Bs is 16 kG)), and the one whose Br / Bs is 0.5 or less is completely isotropic. Property, 0.5 to less than 0.65 is defined as isotropic, and 0.65 or more is defined as anisotropy.

The rare earth element (R) containing Y of the present invention may be one or more selected from Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu. . Among these, it is particularly preferable to use Nd. B is essential for stably depositing a tetragonal Nd ₂ Fe ₁₄ B type crystal structure.

  The anisotropic magnet powder of the first invention is subjected to high-temperature hydrogen treatment and R is 11 or more and 15 or less, B is 5 or more and 8 or less, and one or two of Ga and Nb are 0.01 or more and 1.0, respectively. Hereinafter, the remainder consists of Fe and inevitable impurities.

When R is 11 at% or less, an α-Fe phase is precipitated, and even if heat treatment is performed, the α-Fe phase does not disappear and the magnetic properties are deteriorated. On the other hand, when R is 15 at% or more, the Nd _rich phase increases, the Nd ₂ Fe ₁₄ B phase as the main phase decreases, and the magnetic properties deteriorate.

When B is 5 at% or less, an Nd ₂ Fe ₁₇ phase is precipitated, and this Nd ₂ Fe ₁₇ phase is soft magnetism, so that the magnetic properties deteriorate. On the other hand, when B is 8 at% or more, the B _rich phase and the Nd _1.1 Fe ₄ B ₄ phase increase and the Nd ₂ Fe ₁₄ B phase as the main phase decreases to deteriorate the magnetic properties.

Nb added is an element that makes it easy to control the reaction rate of transfer in the direction from Nd ₂ Fe ₁₄ B to Fe ₂ B. If it is 0.01 at% or less, it is difficult to control the transfer, and 1.0 at% or more. Then, reduce the coercive force. Ga is an element that enhances the coercive force, and if it is 0.01 at% or less, there is no effect of enhancing the coercive force. On the other hand, if it is 1.0 at% or more, the coercive force is decreased.

  The anisotropic magnet powder of the second invention is subjected to high-temperature hydrogen treatment, and in terms of atomic percentage, R is 11 or more, 15 or less, B is 5 or more and 8 or less, Co is 25 or less, and one or two of Ga and Nb are each 0.00. 01 or more and 1.0 or less, and the remainder consists of Fe and inevitable impurities.

  Co is not a particularly essential element, but it is an element that makes it easy to control the reaction rate of orientation transfer by adding it, and raises the Curie temperature as conventionally known. Has reduced the saturation magnetization. For this reason, the addition of 25 at% or more results in a residual magnetic flux density of 1.2 T or less, leading to a decrease in magnetic properties.

  The anisotropic magnet powder of the third invention is subjected to high-temperature hydrogen treatment and R is 11 or more and 15 or less, B is 5 or more and 8 or less, Co is 25 or less, and one or two of Ga and Nb are each 0.00. 01 or more and 1.0 or less, the total of one or two of Zr, V, Mn, Ni, Cr, Cu, Al, Si, and Mo is 0.01 or more and 3 or less, and the remainder consists of Fe and inevitable impurities .

  Zr, V, Mn, Ni, Cr, Cu, Al, Si, and Mo added to the third invention are all elements that control the reaction rate, but the effect is not seen at 0.01 at% or less. . On the other hand, if it is 3 at% or more, a precipitated phase or the like is present and the coercive force is lowered.

The rare earth magnet powders of the first to third inventions have an anisotropy (Br / Bs, where Bs is 1.6T (16 kG)) of 0.65 or more. As other magnetic characteristics, Br is 1.2 to 1.5 T (12 to 15 kG), iHc is 636 to 1272 kA / m (8.0 to 16.0 kOe), and (BH) max is 238 to 358 kJ / It has a characteristic of M ³ (30 to 45 MGOe).

  In addition, the method for producing the rare earth magnet of the present invention is not particularly limited in the raw material preparation step, but a high-purity material is used, and each is prepared so as to have a predetermined composition, and these are mixed. Then, it is melted in a melting furnace or the like and casted to make an alloy ingot, which is used as a raw material. The raw material ingot is homogenized to reduce the composition distribution bias. Further, the homogenized ingot can be pulverized into a powder and used as a raw material.

  This homogenization treatment has a temperature range of 1000 to 1150 ° C., and if it is lower than 1000 ° C., it takes a long time for the homogenization treatment, resulting in a decrease in productivity. On the other hand, if it exceeds 1150 ° C., the ingot melts, which is not preferable.

The reaction rate V between the alloy and hydrogen when the alloy of the present invention occludes hydrogen is V = V ₀ · (PH ₂ / P) ^1/2 · exp (-Ea / RT)
It is represented by Here, V ₀ : frequency factor, PH ₂ : hydrogen gas pressure (Pa), P ₀ : dissociation pressure, Ea: activation energy (J / molK), T: temperature (K). Since this reaction rate is considered to be proportional to the tissue transformation rate, the tissue transformation rate is evaluated by this reaction rate.

That is, the reaction rate of the forward transformation reaction of the structure is set to a reference reaction rate where the reaction rate V _b when the reaction temperature is 830 ° C. and the hydrogen gas pressure is 0.1 MPa (1 atm) is V _b = 1. The relative reaction rate V _r based on the rate was defined. V _r can be expressed by the following equation.
V _r = (1 / 0.576) · (PH ₂ ) ^1/2 · exp (−Ea / RT)

  For the reverse transformation of the structure, the reaction temperature was 830 ° C. and the hydrogen gas pressure was 0.001 MPa (0.01 atm) as the standard reaction rate. The relative reaction rate of the reverse transformation reaction can be determined in the same manner.

  The forward transformation reaction in which the alloy occludes hydrogen is an exothermic reaction, and the reaction temperature is accelerated at the beginning of the forward transformation. The reaction temperature here is a temperature at which the alloy occludes hydrogen and undergoes a normal transformation, and is not a control temperature of the reactor. Therefore, the actual reaction temperature is greatly different from the control temperature of the reactor. It is also conceivable that the hydrogen gas pressure varies greatly due to hydrogen storage. For example, in a mixed gas atmosphere of hydrogen gas and inert gas, the hydrogen gas concentration around the alloy that absorbs hydrogen and causes forward transformation may be greatly reduced. Strict reaction temperature control and hydrogen gas pressure control are required to obtain highly anisotropic magnetic powder.

When the relative reaction rate of the forward transformation is outside the relative reaction rate of 0.25 to 0.50, the anisotropy decreases. And because, by reaction order transformation, when the forward transformation by hydrogen storage rare earth alloy of NdFeB, the large number of fine Fe ₂ B crystal orientation of Nd ₂ Fe ₁₄ B is considered to be caused by normal transformation I think that it is because it is transcribed correctly. When the relative reaction rate of the forward transformation is outside the reaction rate range of 0.25 to 0.50, the transfer to Fe ₂ B is not sufficient and the anisotropy becomes low. In such a case, at present, it is considered impossible to increase the anisotropy in a later process.

  It is impossible in a normal furnace to manage the relative reaction rate of the forward transformation that accelerates with the reaction within the relative reaction rate range of 0.25 to 0.50. For this reason, a new heat treatment furnace with an endothermic means that offsets the heat generated during the reaction was developed and used. In this heat absorption means, a hydrogen storage alloy is placed in a tube, this tube is placed in a furnace, and the hydrogen gas pressure in the tube is reduced in reverse to the heat generated by the reaction, the dehydrogenation reaction proceeds, the heat is absorbed, and the reaction The heat generation is absorbed and offset. Thereby, the control temperature of the furnace and the reaction temperature can be made substantially equal.

  The forward transformation reaction ideally ends in about 30 minutes, but industrially the reaction time depends on the throughput. After completion of the forward transformation, the coercive force of the magnet powder obtained by continuing the heat treatment at the temperature at which the forward transformation has occurred for at least 1 hour is improved. This is thought to be related to the relaxation and removal of internal distortion caused by forward transformation. If internal distortion remains, it is considered that the structure becomes non-uniform after reverse transformation and the coercive force decreases.

Thereafter, the stored hydrogen is dehydrogenated to cause reverse transformation. This reverse transformation is transferred to the crystal orientation of Nd ₂ Fe ₁₄ B which produces the crystal orientation of Fe ₂ B.

In order to transfer the orientation of Fe ₂ B at the time of this reverse transformation, it is preferably caused to occur within a relative reaction rate range of 0.1 to 0.4. Specifically, this reverse transformation is achieved by maintaining the hydrogen gas pressure at 1/100 or less of the forward transformation hydrogen gas pressure. The reverse transformation is an endothermic reaction opposite to the forward transformation, and the reaction temperature is accelerated at the start of the reverse transformation. Therefore, in order to maintain the actual reaction temperature at 780 to 840 ° C., a furnace capable of controlling the reaction in the same manner as in the normal transformation is required.

This reverse transformation theoretically ends within 10 minutes and industrially depends on the throughput. After completion of the reverse transformation, it is preferable to hold at the reverse transformation temperature for at least 25 minutes or more to remove hydrogen contained in the rare earth magnet powder having the produced Nd ₂ Fe ₁₄ B crystal. Thereby, the coercive force is improved. This is because if the dissociated hydrogen remains in the alloy, the coercive force is significantly impaired. Thereafter, it is cooled to obtain the anisotropic magnet of the present invention. Cooling is at least 5 ° C./min. It is desirable to carry out at the cooling rate.

  When the raw material on the ingot is used, the rare earth magnet on the obtained ingot can be easily pulverized with a mortar or the like. Further, when a powdery raw material is used, it may be solidified by aggregation or the like, but can be easily pulverized with a mortar or the like.

  The rare earth bonded permanent magnet using the rare earth magnet powder of the present invention is manufactured using the obtained rare earth magnet powder and a resin that serves as a binder for the magnet powder. At this time, a thermosetting resin such as an epoxy resin can be used as the binder resin, and a mixture obtained by mixing the resin and magnet powder is pressurized under a predetermined magnetic field for magnetization. After molding by molding or the like, heat treatment is performed to cure the resin, and an anisotropic rare earth permanent bonded magnet can be formed.

[Operation of the invention]
The anisotropic magnet powder of the present invention has a large anisotropy such that Br / Bs (where Bs is 1.6T (16 kG)) is 0.65 or more. Further, the residual magnetic flux density and the coercive force are 1.2T (12 kG) and 636 kA / m (8 kOe) or more, respectively, and the magnetic characteristics are excellent. An anisotropic bonded magnet using these magnet powders has a high (BH) max of 135 kJ / m ³ (17 MGOe) or more.

  In addition, the method for producing an anisotropic rare earth magnet of the present invention can easily obtain a rare earth magnet having large anisotropy by controlling the relative reaction rates of the forward transformation reaction and the reverse transformation reaction of the high-temperature hydrogen heat treatment.

  Hereinafter, specific examples will be described.

Example 1
Nd is used as the main component of R, and R, Pr, B, Ga, Nb, and Fe are mixed in the composition shown in Table 1, and the mixture is melted and cast in a button arc melting furnace to have different compositions. Samples 1-12 and 32-36 were made. In Table 1, the content of each element is shown as an atomic percentage, and the entire alloy is set to 100 at%, and Fe is the remainder.

  The sample subjected to the homogenization treatment was reduced to a very small amount of 15 g and placed in a quartz tube, and was connected to a gas pressure control device by a conduit so that the hydrogen gas pressure in the quartz tube could be controlled. An infrared furnace was used as the heating furnace, a thermocouple was used for temperature measurement, the temperature of the sample and the atmosphere was measured, and the furnace was controlled based on these temperatures.

  Hydrogen gas was introduced into the quartz tube so that the hydrogen gas pressure at the forward transformation relative reaction rate shown in Table 2 was obtained, and the mixture was heated in this state and heated to the reaction temperature in about 60 minutes. When the temperature of the sample exceeds the temperature of the atmosphere at the start of the reaction, heating is stopped immediately, the temperature of the atmosphere is lowered by cooling with heat dissipation, the heat generated by the reaction is absorbed, and the sample temperature is kept within + 5 ° C of the target reaction temperature. I tried to sag. Since the sample is as small as 15 g and an infrared furnace is used, the atmospheric temperature in the quartz tube can be controlled relatively easily.

  Thereafter, heat treatment was performed at 820 ° C. and a hydrogen gas pressure of 0.03 MPa (0.3 atm) for 3 hours.

  Thereafter, dehydrogenation was performed by releasing hydrogen gas in the quartz tube so that the reverse transformation relative speed was 0.26, and the reverse transformation reaction was advanced. In this reverse transformation reaction by dehydrogenation, the hydrogen gas pressure is controlled delicately. When the temperature starts to decrease due to the endothermic reaction, the depressurization of the hydrogen gas pressure is stopped, and when the temperature returns to the predetermined temperature, the depressurization is resumed. It was controlled by the method, and was controlled within a range of −5 ° C. of the target temperature, and was 0.0001 MPa (0.001 atm) which is 1/100 or less of the hydrogen gas pressure when storing the hydrogen gas.

  Heat treatment at a predetermined temperature was continued for 30 minutes after the start of the reverse transformation reaction by dehydrogenation. Thereafter, the system was cooled to finish the hydrogen treatment. This produced a rare earth magnet powder.

  The obtained rare earth magnet powder was measured for residual magnetic flux density, intrinsic coercive force, and (BH) max to determine the anisotropic ratio. Table 2 shows the hydrogen treatment conditions.

  Moreover, using the obtained magnet powder, 3g of phenol resin was used with respect to 100g of magnet powder powder as a thermosetting resin, and it compression-molded in the type | mold, and obtained the bonded magnet. The (BH) max of this bonded magnet was also measured and shown in Table 2.

(Example 2)
Nd is used as the main component of R, and R, Pr, B, Co, Ga, Nb, and Fe are mixed in the composition shown in Table 3, and the mixture is melted and cast in a button arc melting furnace to have different compositions. Alloy ingot samples 13 to 20 and 37 were prepared. In Table 3, the content of each element is shown as an atomic percentage, and the whole alloy is set to 100 at%, and Fe is the remainder.

  Rare earth magnet powders were produced in the same manner as in Example 1 under the hydrogen treatment conditions shown in Table 4.

  The obtained rare earth magnet powder was measured for residual magnetic flux density, intrinsic coercive force, and (BH) max to determine the anisotropic ratio. It shows in Table 4 together with hydrogen treatment conditions.

  Moreover, the bonded magnet using the obtained magnet powder was obtained. The (BH) max of this bonded magnet was also measured and shown in Table 4.

(Example 3)
Nd is used as the main component of R, and R, Pr, B, Co, Ga, Nb, Fe, Zr, V, Mn, Ni, Cr, Cu, Al, Si, and Mo are mixed in the composition shown in Table 5. The mixture was melted and cast in a button arc melting furnace to prepare alloy ingot samples 21 to 31 and 38 having different compositions. In Table 5, the content of each element is shown in atomic percentage, and the whole alloy is set to 100 at%, and Fe is the remainder.

  Rare earth magnet powders were produced in the same manner as in Example 1 under the hydrogen treatment conditions shown in Table 6.

  The obtained rare earth magnet powder was measured for residual magnetic flux density, intrinsic coercive force, and (BH) max to determine the anisotropic ratio. Table 6 shows the hydrogen treatment conditions.

  Moreover, the bonded magnet using the obtained magnet powder was obtained. The (BH) max of this bonded magnet was also measured, and the value is also shown in Table 6.

As can be seen from the table, the magnet powder having a controlled relative reaction rate during the hydrogen treatment of the present invention has a high anisotropy ratio of 0.79 or more and Br of 1.2 to 1.5 T (12 -15 kG), iHc is 636 to 1272 kA / m (8.0 to 16 kOe), and (BH) max is 238 to 358 kJ / m ³ (30 to 45 MGOe).

  Further, as can be seen from the magnet powders of Samples 32-38, even when the relative reaction rate is controlled, the magnetic properties are deteriorated when the composition of the raw material alloy is out of the composition range of the present invention. That is, when the amount of R decreases, the anisotropy decreases to 0.37, the anisotropy is lost, the magnetic characteristics are greatly decreased, and conversely, when R increases, (BH) max decreases. When the amount of Ga increases to 2.0 at%, iHc decreases, and since B increases, the magnetic characteristics decrease. Even if Nb is large, iHc is reduced, and if Co is increased, iHc is reduced and magnetic characteristics are deteriorated. Further, by adding Ni in a large amount of 5.0 at%, iHc is reduced and magnetic characteristics are deteriorated.

Claims (24)

  Anisotropy (Br / Bs, where Bs is 1.6T (16 kG)) is 0.65 or more, and a rare earth element containing yttrium (Y) (hereinafter referred to as R) is 11 to 15 atm in atomic percentage. %, Boron (B) of 5 to 8 at%, 0.01 to 1.0 at% of gallium (Ga) and niobium (Nb), respectively, and the balance of iron (Fe). An anisotropic rare earth magnet powder comprising impurities. Residual magnetic flux density (Br) is 1.2 to 1.5 T (12 to 15 kG), intrinsic coercive force (iHc) is 636 to 1272 kA / m (8.0 to 16 kOe), and (BH) max is 238 to 358 kJ / m. ^3. The rare earth magnet powder according to claim 1, wherein the rare earth magnet powder is (30 to 45 MGOe).   Hydrogen is added to an RFeB alloy composed of rare earth elements (R) including yttrium (Y), iron (Fe), boron (B), and one or two of gallium (Ga) and niobium (Nb). After the forward transformation to be occluded proceeds within the relative reaction rate range of 0.25 to 0.50, the reverse transformation in which hydrogen is released is caused to occur within the relative reaction rate range of 0.1 to 0.4, and anisotropic A method for producing anisotropic rare earth magnet powder, characterized in that an RFeB-based alloy imparted with properties is provided.   In the forward transformation, the hydrogen gas pressure is set to 0.01 to 0.06 MPa (0.1 to 0.6 atm), and the temperature of the RFeB-based alloy is maintained within a range of 780 to 840 ° C., and hydrogen is added to the alloy. The method for producing anisotropic rare earth magnet powder according to claim 3, wherein   The method for producing anisotropic magnet powder according to claim 4, wherein the forward transformation proceeds while suppressing an increase in the reaction temperature by cooling and removing heat generated at the start of the forward transformation reaction.   The method for producing an anisotropic rare earth magnet powder according to claim 3, wherein after the forward transformation is completed, the heat treatment is continued at the temperature at which the forward transformation has occurred.   The said reverse transformation maintains hydrogen gas pressure 1/100 or less of the said forward transformation, and maintains temperature in the range of 780-840 degreeC, and performs a dehydrogenation reaction, The difference of Claim 3 characterized by the above-mentioned. A method for producing an anisotropic rare earth magnet powder.   The method for producing an anisotropic rare earth magnet powder according to claim 7, wherein the reverse transformation proceeds while suppressing a decrease in the relative reaction rate by heating and supplementing the endotherm accompanying the reverse transformation.   High-temperature hydrogen heat treatment, anisotropy (Br / Bs, where Bs is 1.6T (16 kG)) is 0.65 or more, and rare earth elements (R) containing yttrium (Y) are 11 to 11 in atomic percent. 15at%, boron (B) 5-8at%, 0-25at% cobalt (Co), 0.01-1.0at% gallium (Ga), niobium (Nb) one or two An anisotropic rare earth magnet powder comprising a seed and the balance of iron (Fe) and inevitable impurities. The residual magnetic flux density Br is 1.2 to 1.5 T (12 to 15 kG), the intrinsic coercive force (iHc) is 636 to 1272 kA / m (8.0 to 16 kOe), and (BH) max is 238 to 358 kJ / m ³ ( The rare earth magnet powder according to claim 9, which is 30 to 45 MGOe).   It consists of one or two of rare earth elements (R) containing yttrium (Y), iron (Fe), boron (B), cobalt (Co), gallium (Ga), and niobium (Nb). After the forward transformation for occluding hydrogen in the RFeCoB-based alloy is allowed to proceed within the relative reaction rate range of 0.25 to 0.50, the reverse transformation where hydrogen is released is within the relative reaction rate range of 0.1 to 0.4. A method for producing anisotropic rare earth magnet powder, characterized in that an RFeCoB-based alloy imparted with anisotropy is generated.   In the forward transformation, the hydrogen gas pressure is set to 0.01 to 0.2 MPa (0.1 to 2.0 atm), and the temperature of the RFeB alloy is maintained within a range of 780 to 850 ° C., and hydrogen is added to the alloy. The method for producing anisotropic rare earth magnet powder according to claim 11, wherein occlusion is performed.   The method for producing anisotropic magnet powder according to claim 12, wherein the forward transformation is advanced while suppressing an increase in reaction temperature by cooling and removing heat generated at the start of the forward transformation reaction.   The method for producing an anisotropic rare earth magnet powder according to claim 11, wherein after the forward transformation is completed, the heat treatment is continued at a temperature at which the forward transformation is caused.   12. The reverse transformation according to claim 11, wherein the reverse transformation is carried out by maintaining the hydrogen gas pressure at 1/100 or less of the forward transformation and maintaining the temperature in a range of 780 to 850 ° C. A method for producing an anisotropic rare earth magnet powder.   The method for producing an anisotropic rare earth magnet powder according to claim 15, wherein the reverse transformation proceeds while suppressing a decrease in the relative reaction rate by heating and supplementing the endotherm accompanying the reverse transformation.   High-temperature hydrogen heat treatment, anisotropy (Br / Bs, where Bs is 1.6T (16 kG)) is 0.65 or more, and rare earth elements (hereinafter referred to as R) containing yttrium (Y) are atoms. Percentage of 11-15 at%, boron (B) 5-8 at%, 0-25 at% cobalt (Co), 0.01-1.0 at% gallium (Ga), niobium (Nb) respectively. Zirconium (Zr), Vanadium (V), Manganese (Mn), Nickel (Ni), Chromium (Cr), Copper (Cu), Aluminum (1 type or 2 types in total and 0.01 to 3.0 at%) An anisotropic rare earth magnet powder comprising one or two of Al), silicon (Si), and molybdenum (Mo), the balance being iron (Fe) and inevitable impurities. Residual magnetic flux density (Br) is 1.2 to 1.5 T (12 to 15 kG), intrinsic coercive force (iHc) is 636 to 1272 kA / m (8.0 to 16 kOe), and (BH) max is 238 to 358 kJ / m. The rare earth magnet powder according to claim 17, which is ³ (30 to 45 MGOe).   One or two of rare earth elements (R) containing yttrium (Y), iron (Fe), boron (B), cobalt (Co), gallium (Ga) and niobium (Nb), zirconium ( One or two of Zr), vanadium (V), manganese (Mn), nickel (Ni), chromium (Cr), copper (Cu), aluminum (Al), silicon (Si), and molybdenum (Mo); The forward transformation for absorbing hydrogen in the RFeCoB-based alloy consisting of the above is allowed to proceed within the relative reaction rate range of 0.25 to 0.50, and then the reverse transformation in which hydrogen is released is the relative reaction rate of 0.1 to 0.4. A method for producing anisotropic rare earth magnet powder, characterized in that an RFeCoB-based alloy imparted with anisotropy is generated within a range.   In the forward transformation, the hydrogen gas pressure is set to 0.01 to 0.3 MPa (0.1 to 3.0 atm), the temperature of the RFeB alloy is maintained within a range of 780 to 850 ° C., and hydrogen is added to the alloy. The method for producing anisotropic rare earth magnet powder according to claim 3, wherein   21. The method for producing anisotropic magnet powder according to claim 20, wherein the forward transformation proceeds while suppressing an increase in the reaction temperature by cooling and removing heat generated at the start of the forward transformation reaction.   20. The method for producing anisotropic rare earth magnet powder according to claim 19, wherein after the forward transformation is completed, the heat treatment is continued at the temperature at which the forward transformation has occurred.   The reverse transformation is carried out by maintaining the hydrogen gas pressure at 1/100 or less of the forward transformation and maintaining the temperature in the range of 780 to 850 ° C to perform the dehydrogenation reaction. A method for producing an anisotropic rare earth magnet powder.   24. The method for producing an anisotropic rare earth magnet powder according to claim 23, wherein the reverse transformation proceeds while suppressing a decrease in the relative reaction rate by heating to compensate for the endotherm accompanying the reverse transformation.