JP2631380B2 - Rare earth-iron permanent magnet manufacturing method - Google Patents

Description

The present invention relates to a method for producing a rare earth-iron permanent magnet.

[Conventional technology]

Heretofore, the following three methods have been reported as rare earth-iron magnets.

(1) Magnet by sintering method based on powder metallurgy (Reference Document 1) (2) A quenched thin strip manufacturing device used for manufacturing an amorphous alloy, quenched flakes having a thickness of about 30 μm, and the flakes are made of resin. Magnet combining. (Reference Document 2) (3) A magnet obtained by subjecting the same slice used in the method of (2) to mechanical orientation treatment by a two-stage hot pressing method. (Reference 2) Reference 1: M.Sagawa, S.Fujimura, N.Togawa, H.Yamamoto
and Y. Matuura; J. Appl. Phys. Vol. 55 (6), 15 March 19
84, P2083 Reference 2: RWLee; Appl. Phys. Lett. Vol. 46 (8), 15A
prol 1985, P790 The above prior art will be described with reference to the literature. First (1)
In the sintered magnet of (1), an alloy ingot is produced by melting and casting, and pulverized into a magnet powder having a particle size of about 3 μm. The magnet powder is kneaded with a binder serving as a molding aid, and is press-molded in a magnetic field to complete a compact.
The compact is sintered in argon at a temperature of around 1100 ° C. for 1 hour and then quenched to room temperature. After sintering, if heat treatment is performed at a temperature of about 600 ° C., the coercive force is further improved.

With the magnet of (2), a quenched ribbon of an R-Fe-B alloy is first produced at an optimum rotation speed of the quenched ribbon manufacturing apparatus. The obtained ribbon has a ribbon shape with a thickness of 30 μm, and polycrystals having a diameter of 1000 mm or less are gathered. The ribbon is brittle and easily broken, and since the crystal grains are distributed isotropically, it is magnetically isotropic. If the ribbon is adjusted to an appropriate particle size, kneaded with a resin and press-molded, about 85% by volume can be filled with a pressure of about 7 ton / cm ² .

In the magnet of (3), a ribbon-shaped quenched ribbon or a strip of ribbon is first placed in a vacuum or an inert atmosphere for about 700 hours.
Place in graphite or other heat resistant press mold preheated at ℃. Uniaxial pressure is applied when the ribbon reaches the desired temperature. The temperature and time are not specified, but T = 725 ± 25 ° C, and the pressure is P ~
1.4ton / cm ² is suitable. At this stage, the magnet is generally isotropic, although slightly oriented in the pressing direction. The next hot pressing is performed in a large area mold. It is most commonly pressed at 700 ° C. at 0.7 ton for a few seconds. Then, the easy axis of magnetization of the sample is oriented in parallel with the pressing direction that is half the initial thickness, and the alloy becomes anisotropic. These steps are performed in a two-stage hot pressing method (two-sta
ge hot-press procedure). By this method, a dense and anisotropic R-Fe-B magnet can be manufactured. In addition, the crystal grain of the ribbon ribbon made by the first melt spinning method should be smaller than the grain size when it shows the maximum coercive force, and the crystal grain will be coarsened later during hot pressing. Keep the particle size to the optimum.

[Problems to be solved by the invention]

Although the rare earth-iron based magnets can be produced for the time being by the above-mentioned conventional techniques, the magnets utilizing these techniques have the following disadvantages. In the sintered magnet of (1), it is essential to powder the alloy, but since the R-Fe-B-based alloy is very active against oxygen, when powdered, the oxidation is further increased and the sintered body is hardened. The oxygen concentration in the inside is inevitably high. Also, when forming the powder, a molding aid such as zinc stearate must be used, which is removed in advance in the sintering process, but a few percent are in the form of carbon in the magnet body. Will remain. This carbon significantly reduces the magnetic performance of R-Fe-B. The molded body after the addition of the molding aid and press molding is called a green pair. It is very brittle and difficult to handle. Therefore, it is a great disadvantage that it takes a considerable amount of time to neatly arrange them in the sintering furnace. Because of these drawbacks, generally speaking, the production of sintered magnets of R-Fe-B diameter requires not only expensive equipment but also low production efficiency and high magnet production costs. I will. Therefore,
It is hard to say that the R-Fe-B magnet is a magnet that sufficiently draws out the low raw material cost.

The magnets (2) and (3) use a vacuum melt spinning device. This device is currently very productive and expensive. In (2), the product is low energy product because it is isotropic in principle, and the squareness of the hysteresis loop is not good, which is disadvantageous in terms of temperature characteristics and use.

The method (3) is a unique method of using a hot press in two stages, but it is unavoidable that it will be very inefficient when actually considering mass production.

The method for producing a rare earth-iron permanent magnet according to the present invention solves these disadvantages, and an object thereof is to obtain a high performance and low cost rare earth-iron permanent magnet.

[Means for Solving the Problems] The first invention of the present invention provides a method for manufacturing a semiconductor device, comprising: R (where R is at least one of rare earth elements including Y): 8 to 30 atomic%;
A step of melting and casting an iron-based alloy containing 8 at% and Ga: 0.1 to 6 at%;
A step of making the crystal grains fine and orienting the crystal axis in a specific direction by magnetically anisotropy by hot working at a temperature of at least ℃. This is a method for manufacturing a magnet.

According to a second aspect of the present invention, R (where R is at least one of the rare earth elements including Y): 8 to 30 atomic%, B: 2 to 2
8 atomic%, Co: 50 atomic% or less (except 0), and
Ga: A step of melting and casting an iron-based alloy containing 0.1 to 6 atomic% and hot-working the obtained cast ingot at a temperature of 500 ° C. or more to refine crystal grains and increase crystal axes. A step of orienting in a specific direction and magnetically anisotropically forming the rare-earth-iron-based permanent magnet.

According to a third aspect of the present invention, R (where R is at least one of the rare earth elements including Y): 8 to 30 atomic%, B: 2 to 2
8 atomic%, Co: 50 atomic% or less (except 0), and
Ga: 0.1 to 6 atomic% and Al: 15 atomic% or less (however, 0
(Except for iron alloys) and casting, and hot-working the resulting cast ingot at a temperature of 500 ° C or higher to refine the crystal grains and move the crystal axis in a specific direction Orienting and magnetically anisotropically producing the rare-earth-iron-based permanent magnet.

According to a fourth aspect of the present invention, R (where R is at least one of rare earth elements including Y): 8 to 30 atom%, B: 2-2 to 2
8 atomic%, Co: 50 atomic% or less (except 0), Al: 15
Atomic% or less (except 0), Cu: 6 atomic% or less (excluding 0), and a step of melting and casting an iron-based alloy containing 0.1 to 6 atomic% of Ga: 500 ℃
Hot working at the above temperature to refine the crystal grains and orient the crystal axis in a specific direction, thereby magnetically making the crystal anisotropic.
This is a method for manufacturing an iron-based permanent magnet.

In the first to fourth aspects of the present invention, it is preferable that the method further includes a step of pulverizing the alloy and a step of kneading and shaping the obtained magnetic powder and an organic binder to form a resin-bound magnet. In this case, the pulverization of the alloy is preferably performed at a particle size such that each of the pulverized magnetic powders contains a plurality of crystal grains therein.

As described above, the sintering method and the quenching method, which are the existing methods for producing rare earth-iron permanent magnets, have major disadvantages such as difficulty in powder management by pulverization and poor productivity. In order to remedy these drawbacks, the present inventors have started research on magnetization in a bulk state, and first refined crystal grains by hot working in the composition range of claims 1 to 4. And a sufficient coercive force can be obtained, and a resin-bonded magnet can be manufactured by crushing the ingot after hot working. In this method, the anisotropy due to hot working is not required to be two steps as in the quenching method shown in Reference Document 2, but only one step, and the coercive force after working is greatly increased due to finer grains. It shows a completely different phenomenon.
Further, since it is not necessary to pulverize the cast ingot, it is not necessary to perform strict atmosphere control as in the sintering method, and the equipment cost is greatly reduced. Further, the resin-bonded magnet does not have the problem that it is isotropic in principle like a magnet obtained by the quenching method, and an anisotropic resin-bonded magnet can be obtained.
The high performance and low cost characteristics of Fe-B magnets can be used.

There is a study on magnetization in bulk state in Reference 3, Hiroaki Miho et al. (The Japan Institute of Metals, Autumn 1985 lecture, lecture number (544)), but this research is based on Nd _16.2 Fe _50.7 C
o It is a small sample sucked up by dissolving in the atmosphere by blowing argon gas with a composition of _22.6 V _1.3 B _9.2 , and it is considered that the effect of quenching and refinement of crystal grains was obtained because a small amount was collected. With this composition, in normal casting, the main phase, the Nd ₂ Fe ₁₄ B phase, is coarsened and can be anisotropic by hot working, but our experiments show that it is difficult to obtain sufficient coercive force as a permanent magnet. I confirmed it. In order to obtain a sufficient coercive force by ordinary casting, a low B composition as in the present invention is essential.

As the composition of the conventional R-Fe-B-based magnet, R ₁₅ Fe ₇₇ B ₃ as represented in Reference 1 has been optimized. This composition has a composition R _11.7 Fe obtained by atomizing the main phase R ₂ Fe ₁₄ B compound.
_82.4 B It has shifted to the side rich in RB compared to _5.9 . This means that not only the main phase but also R ri
It is explained that a non-magnetic phase called a ch phase and a B rich phase is required. However, in the composition according to the present invention, the peak value of the coercive force exists at the point where the amount of B shifts to the smaller side. In this composition range, the coercive force is drastically reduced in the case of the sintering method, so that it has not been a problem so far.
However, in a normal casting method, a high coercive force can be obtained only in the composition range of the present invention, and conversely, a sufficient coercive force cannot be obtained on the side taking B, which is the mainstream composition of the sintering method.

These points are considered as follows. First, whether using the sintering method or the casting method, the coercive force mechanism itself is nucl
According to eation.model. This is the initial magnetization curve of the two can be seen from the fact that show a steep rise as SmCo _5. The coercive force of this type of magnet is basically based on a single domain model. That is, in this case, if the R ₂ Fe ₁₄ B compound having a large crystal magnetic anisotropy is too large, it will have a domain wall in the grain, and the reversal of magnetization easily occurs due to the movement of the domain wall, and the coercive force is reduced small. On the other hand, when the particle becomes smaller and becomes smaller than a certain size, the particle has no domain wall, and the reversal of magnetization proceeds only by rotation, so that the coercive force increases. That is, in order to obtain an appropriate coercive force, the R ₂ Fe ₁₄ B phase needs to have an appropriate particle size. The particle size is suitably about 10 μm. In the case of the sintering type, the particle size can be adjusted by adjusting the particle size before sintering. However, in the case of casting, R ₂ Fe
_Since the size of the ₁₄ B compound is determined at the stage of solidification from melting, attention must be paid to the composition and solidification process. In particular, the meaning of the composition is large. When B exceeds 8 atomic%, the size of the R ₂ Fe ₁₄ B phase after casting easily exceeds 100 μm, and the casting is required unless a quenching device such as Reference Document 2 is used. In this state, it is difficult to obtain a coercive force. On the other hand, in the low-boron region as described above, the particle size can be easily reduced by devising the mold and casting temperature. In either case, the hot working reduces the size of the main phase R ₂ Fe ₁₄ B phase, so that the coercive force increases as compared to before the working. In other words, the region where the coercive force can be obtained in the cast state can be said to be a composition rich in Fe compared to R ₂ Fe ₁₄ B.In the solidification stage, Fe appears as the primary crystal first, followed by peritectic reaction The R ₂ Fe ₁₄ B phase appears. At this time, since the cooling speed is much faster than the equilibrium reaction, the cooling speed solidifies in such a manner that the R ₂ Fe ₁₄ B phase surrounds the primary crystal Fe. In this composition region, since it is a low B region, it is natural that the typical composition of the sintering type R ₁₅ Fe
Magnets such as found B rich phase ₇₇ B ₈ is almost negligible in quantity. Heat treatment at a temperature of 250 ° C or higher requires primary Fe
Is diffused to reach an equilibrium state, and the coercive force largely depends on the diffusion of the Fe phase.

Next, resin bonding will be described. Certainly, the resin-coupled magnet can be produced even by the quenching method of Reference 2. However, the powder produced by the quenching method is magnetically isotropic because polycrystals having a diameter of 1000 mm or less are aggregated isotropically, and an anisotropic magnet cannot be produced. -The characteristic of low cost and high performance of B diameter cannot be used.

In addition, there are mainly two reasons that a sintered R-Fe-B magnet has not been ground to produce a resin-bonded magnet. First, it is necessary to pay attention to the fact that the critical radius of the single magnetic domain of the R ₂ Fe ₁₄ B phase is smaller by one digit than that of SmCo ₅ or the like, and is on the order of submicron. It is very difficult to grind to this particle size by ordinary mechanical grinding, and the powder is too activated, so that it is easily oxidized and ignites, and the coercive force is not enough for the particle size. We examined the relationship between grain size and coercive force, but the coercive force did not fall out of the range of several KOe at most, and the coercive force hardly increased even by surface treatment. The next problem is distortion due to machining. For example, 10KOe in the sintered state
Mechanical grinding of a magnet with a coercive force of
m powder has only a coercive force of 1 KOe or less. SmCo is said to follow a similar coercive force mechanism (nucleation model)
_{With five} magnets, such a drastic decrease in coercive force does not occur, and powder having a coercive force can be easily produced. As a cause of such a phenomenon, it can be expected that the influence of processing strain at the time of pulverization is considerably large in the case of the R-Fe-B system. This is a serious problem when a small magnet such as a rotor magnet of a step motor for a watch is cut out from a sintered block.

For the above two reasons, that is, the critical radius is small and the influence of the processing strain is large, the resin-bonded magnet cannot be formed by the normal pulverization. In order to obtain a powder having a coercive force, as shown in Reference 2, R ₂ Fe ₁₄
What is necessary is just to make the powder which has many B particles. However, the quenching method of Reference 2 has a problem in productivity. Further, it is practically impossible to produce such a powder by grinding after sintering.
This is because the grains grow to some extent during sintering and become large, so that the grain size before sintering must be further reduced in consideration of the amount. However, with such a particle size, the oxygen concentration of the powder becomes extremely high, and the expected performance cannot be obtained. Therefore, at present, the limit of the particle size (crystal particle size) of the sintered R ₂ Fe ₁₄ B phase is about 10 μm. With such a particle size, the material has almost no coercive force after pulverization. Therefore, we focused on utilizing grain refinement by hot working. It is relatively easy to make the particle size of the R ₂ Fe ₁₄ B phase equal to that of a sintered R—Fe—B magnet after casting. Then, the cast block having the R ₂ Fe ₁₄ B phase having such a particle size is hot-worked, and the particles are refined and oriented, and then pulverized. According to this method, since the particle size of the resin-bound magnet powder is 20 to 30 μm, a large number of R ₂ Fe
₁₄ B particles can be included, and a powder having a coercive force can be produced. Further, since this powder is not isotropic as in the quenching method of Reference 2, and is a powder capable of magnetic field orientation, it can be used as an anisotropic magnet. Of course, at this time, if hydrogen grinding is applied to the grinding, the coercive force is better maintained.

The permanent magnet manufactured according to the first invention of the present invention is R-Fe-B-Ga containing R, Fe, B, and Ga as essential elements.
(N in Table 1 of Example 1 described later)
o.1).

The permanent magnet manufactured according to the second invention has R, F
R-Fe-C containing e, B, Ga and Co as essential elements
It is composed of an o-B-Ga alloy (see Nos. 2 to 4 in Table 1 of Example 1 described later).

The permanent magnet manufactured according to the third invention has R, F
R-F containing e, Co, B, Ga and Al as essential elements
It is composed of an e-Co-B-Ga-Al alloy (see Nos. 8 to 10 in Table 3 of Example 2 described later).

The permanent magnet manufactured according to the fourth aspect of the invention has R, F
It is composed of an R-Fe-Co-B-Ga-Al-Cu alloy containing e, Co, B, Ga, Al, and Cu as essential elements (see Table 3 in Example 2 described later). No. 11).

Hereinafter, the reasons for limiting the composition of the permanent magnet according to the present invention will be described. Rare earths include Y, La, Ce, Pr, Nd, Sm, Eu,
Gd, Tb, Dy, Mo, Eu, Tm, Yb, and Lu are listed as candidates, and one or more of them are used in combination. The highest magnetic performance is obtained with Pr. Therefore, practically, Pr, Nd, Pr-Nd alloy, Ce-Pr-Nd alloy and the like are used. Small amounts of heavy rare earth elements Dy, Tb, etc. are effective for improving coercive force. Main phase of R-Fe-B magnet is R ₂ Fe ₁₄ B. Therefore, when R is less than 8 atomic%, the above compound is no longer formed and a cubic structure having the same structure as that of α-iron is obtained, so that high magnetic properties cannot be obtained. On the other hand, when R exceeds 30 atomic%, the non-magnetic R rich phase increases and the magnetic properties are remarkably deteriorated. Therefore, the range of R is suitably 8 to 30 atomic%. However, in order to form a cast magnet, R8 to 25 atomic% is preferably appropriate.

B is an essential element for forming the R ₂ Fe ₁₄ B phase,
If the content is less than 2 atomic%, a high coercive force cannot be expected because of the rhombohedral R-Fe system. On the other hand, if it exceeds 28 atomic%, the nonmagnetic phase rich in B increases, and the residual magnetic flux density is remarkably reduced. However, the cast magnet is preferably B28 atomic% or less, and if it exceeds that, unless measures such as increasing the cooling rate are taken, the crystal refining becomes insufficient and a large coercive force becomes difficult to obtain.

Co is an element effective for increasing the Curie point of the present magnet, and basically replaces the Fe site to form R ₂ Co ₁₄ B. However, this compound has a small crystal anisotropic magnetic field, As the amount increases, the coercive force of the magnet as a whole decreases. Therefore, in order to provide a coercive force of 1 KOe or more, which is considered as a permanent magnet, the content is preferably within 50 atomic%.

Al reference 4 Zhang Maocai et al. Proceedings of the
8th International Workshopon Rare-Earth Magnet
s.1985, P541 has the effect of increasing the coercive force. Although this document shows the effect on sintered magnets, the effect exists similarly in cast magnets. However
Since Al is a non-magnetic element, increasing the amount of addition decreases the residual magnetic flux density. If it exceeds 15 atomic%, the residual magnetic flux density becomes lower than that of hard ferrite, so it can serve the purpose of a rare earth magnet. Absent. Therefore, the addition amount of Al is 15 atomic%.
The following is good.

Cu has been considered as an impurity element when inexpensive iron is used, as shown in Reference 5, JP-A-59-163803, and the like. However, in the manufacturing method relating to casting and hot working in the present invention, Cu has a great effect on increasing the coercive force and improving the magnetic energy product by improving the hot workability, and is rather an element to be positively added. I have. However, since Cu is a non-magnetic element, the residual magnetic flux density decreases as the amount of addition increases, so that it is preferably 6 atomic% or less.

In addition, the front part or some of the Co, Al, and CU may not be added.

Ga has an effect of increasing the coercive force in the sintering method as shown in Reference 6, Minoru Endo et al. (Nippon Metallurgy, Spring 1987, Lecture No. (422)). The same effect is obtained in the manufacturing method based on the anti-invention, and the effect of improving the magnetic energy product by improving the hot workability is added. However, since Ga is a non-magnetic element, the residual magnetic flux density decreases when the content thereof is increased. If the content is less than 0.1 atomic%, the above-mentioned effect due to aging of Ga is small.

Example 1 Hereinafter, a production method according to the present invention will be described.

First, an alloy having a desired composition is melted in an induction furnace and cast into a mold. Next, various types of hot working are performed to impart anisotropy to the magnet. In this embodiment, not a general casting method,
As a special casting method, Li with large crystal grain fine effect by quenching
quid dynamic compacticn method (Ref. 7, tschin
In addition, J. Appl. Phys. 59 (4), 15 February 1986. P1297) was used. Extrusion, rolling, and hot working
Either stamping or press working was performed at 1000 ° C. As for the extrusion process, a device was devised so that a force was also applied from the die side so that strain was applied isotropically. For the rolling and stamping, the speed of the roll / stamp was adjusted so as to minimize the strain rate. In either method, the axis of easy magnetization of the crystal is oriented so as to be parallel to the direction in which the alloy is pressed.

An alloy having the composition shown in Table 1 was melted, and a magnet was prepared by the method described above. However, the hot working method used is also shown in the table.
All annealing treatments after hot working were performed at 1000 ° C. for 24 hours.

Next, the results are shown. As reference data, the residual magnetic flux density of the sample not subjected to hot working is shown.

Table 2 shows that the hot working increased the residual magnetic flux density and magnetically anisotropically.

Embodiment 2 Here, an embodiment using a normal casting method will be introduced.
First, a composition as shown in Table 3 is cast into a molten iron mold in an induction furnace to form columnar crystals. After performing hot working (pressing in this embodiment) at a working ratio of about 50% or more, annealing was performed at 1000 ° C. for 24 hours to magnetically cure the ingot. At this time, the average grain size of the crystal grains after annealing is about 15
μm. In the case of a casting type, if it is worked into a desired shape without performing hot working, it becomes an in-plane anisotropic magnet utilizing the anisotropy of columnar crystals.

The following Table 4 shows the magnetic properties of the compositions each annealed without hot working and those annealed after hot working.

Here, both (BH) max and iHc show a large increase by hot working. This is because the particles were oriented by the processing and the squareness of the BH curve was greatly improved. Reference 2
In the rapid cooling method, iHc tends to decrease due to processing, and a large increase in iHc is a major feature of the present invention.

(Example 3) Here, an example in which pulverization is performed after hot working to form a resin bond will be introduced. Samples Nos. 9 and 11 in Table 3 of Example 2 were each subjected to a stamp mill and a disc mill to a particle size of about 30 μm.
(Measured with a Fischer Sapthy riser). At this time, the grain system of the crystal grains in the magnetic powder obtained by the pulverization, that is, the particle size of the R ₂ Fe ₁₄ B phase or the R ₂ Co ₁₄ B phase was 2 to 3 μm.

Among the magnetic powders thus obtained, No. 9 powder was kneaded with 2% by weight of an epoxy resin as it was,
Magnetic field shaping and firing were performed. For the powder of No. 11, after performing the silane coupling agent treatment, nylon 1 was used in a ratio such that the volume ratio of the magnetic powder and the organic binder was 6: 4.
The mixture was kneaded with the mixture at about 250 ° C. and injection molded. For these,
The results of measuring the magnetic properties are shown in Table 5 below.

(Example 4) Samples Nos. 9 and 11 in Table 3 of Example 2 and Nd ₁₀ Pr ₅ Fe ₈₁ B ₄ (sample No. 12) and Ce ₃ Nd ₁₀ Pr ₄ Fe ₆₄ as comparative examples.
A sample manufactured in the same manner as in Example 2 for the composition of Co ₁₀ Al ₅ B ₄ (Sample No. 13) was prepared.
A weather resistance test was performed in a constant temperature bath of ℃ 95% RH. Table 6 shows the results.

[Effects of the Invention] As described above, according to the present invention, a coercive force can be obtained only by heat treatment without crushing the ingot as in the conventional sintering method. Also, hot working may be performed in one step instead of two steps as in the quenching method, and the effects include not only an anisotropic effect but also an effect of increasing coercive force.
Due to such characteristics, the manufacturing process can be greatly simplified as compared with the conventional sintering method and quenching method. Furthermore, anisotropic resin-bonded magnets can also be manufactured by grinding the sample after hot working. Also,
The magnet manufactured according to the present invention has excellent weather resistance (corrosion resistance).

Continued on the front page (72) Inventor Toshiaki Yamagami 3-5-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (72) Inventor Tatsuya Shimoda 3-5-5 Yamato, Suwa-shi, Nagano Seiko Epson shares In-company (72) Inventor Nobuyasu Kawai 5-15-29 Kita-Ochiai, Suma-ku, Kobe-shi, Hyogo (56) References JP-A-62-276803 (JP, A) JP-A-64-704 (JP, A)

Claims (4)

(57) [Claims] An iron-based alloy containing R (where R is at least one of rare earth elements including Y): 8 to 30 atomic%, B: 2 to 28 atomic%, and Ga: 0.1 to 6 atomic%. Melting and casting, and hot-working the obtained cast ingot at a temperature of 500 ° C or more to refine the crystal grains and orient the crystal axis in a specific direction, thereby magnetically anisotropically And producing a rare earth-iron permanent magnet. 2. R (where R is at least one of the rare earth elements including Y): 8 to 30 atomic%, B: 2 to 28 atomic%, Co:
A step of melting and casting an iron-based alloy containing 50 atomic% or less (excluding 0) and Ga: 0.1 to 6 atomic%, and hot working the obtained cast ingot at a temperature of 500 ° C. or more. A step of refining the crystal grains, orienting the crystal axis in a specific direction, and magnetically anisotropically forming the rare earth-iron permanent magnet. 3. R (where R is at least one of the rare earth elements including Y): 8 to 30 atomic%, B: 2 to 28 atomic%, Co:
Melting and casting an iron-based alloy containing 50 at% or less (except 0), and Ga: 0.1 to 6 at%, and Al: 15 at% or less (excluding 0); Hot-working the cast ingot at a temperature of 500 ° C. or more to refine the crystal grains and orient the crystal axis in a specific direction, thereby magnetically anisotropically forming a rare earth element. -A method for producing an iron-based permanent magnet. 4. R (where R is at least one of the rare earth elements including Y): 8 to 30 atomic%, B: 2 to 28 atomic%, Co:
Iron-based alloy containing 50 atomic% or less (except 0), Al: 15 atomic% or less (except 0), Cu: 6 atomic% or less (except 0), and Ga: 0.1 to 6 atomic% Melting and casting, and hot-working the resulting cast ingot at a temperature of 500 ° C or higher to refine the crystal grains and orient the crystal axis in a specific direction, thereby magnetically anisotropically And a method of producing a rare earth-iron permanent magnet.