JPH0766022A - Permanent magnet - Google Patents

Abstract

PURPOSE:To improve magnet characteristics such as residual flux density, coercive force, etc., by manufacturing a permanent magnet by using an alloy ingot being prepared by controlling the degree of supercooling and cooling rate of an alloy melt and having a specific crystalline structure as an essential raw material component through specific manufacture. CONSTITUTION:An alloy melt containing a 25-31wt.% rare earth metal, 0.5-1.5wt.% boron and iron is coagulated uniformly under the cooling conditions of the degree of supercooling of 50-500 deg.C and a cooling rate from 500 deg.C/sec to 10000 deg.C/sec through a single roll method. A raw material component mainly comprising an alloy ingot containing not less than 90vol.% columnar crystals having columnar-crystal grain size of the minor axis direction of 0.1-50mum and the major axis direction from 100mum to 300mum acquired through the manufacture is ground, molded and sintered, thus manufacturing a permanent magnet. Accordingly, the permanent magnet, in which the conditions of grinding at the time of production are facilitated and which has excellent magnetic characteristics such as residual flux density, coercive force, etc., and particularly has superior anisotropic characteristics, can be acquired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet having excellent magnet characteristics containing rare earth metals, boron and iron as essential components.

[0002]

2. Description of the Related Art Conventionally, alloy ingots for permanent magnets are generally produced by a die casting method in which a molten alloy is cast in a die. However, when solidifying the alloy melt by the die casting method, in the heat removal process of the alloy melt,
In the initial stage of heat removal, the heat transfer rate is controlled by the mold, but when solidification proceeds, heat transfer between the mold and the solidification phase and in the solidification phase becomes heat removal rate control, and even if the mold cooling capacity is improved, casting inside the ingot and near the mold In the ingot, the cooling conditions are different, and such a phenomenon occurs especially when the ingot thickness is large. When there is a large difference in the cooling conditions between the inside of the ingot and the vicinity of the surface as described above, the primary structure γ-F,
There is a large amount of e, and as a result, the grain size is 10-3 in the center of the ingot.
00 μm of α-Fe remains, and at the same time, the size of the rare earth metal-rich phase surrounding the main phase also increases. On the other hand, in the crushing process in the magnet manufacturing process, the ingot is usually finely pulverized to several microns, but in the case of the ingot obtained by the die casting method, it is difficult to pulverize α-Fe having a large particle size. And, since it contains a large phase rich in rare earth metal, the powder particle size distribution after pulverization becomes non-uniform, which adversely affects the magnetic orientation and sinterability, and finally reduces the magnetic properties of the permanent magnet obtained. There is a drawback that. In the ingot structure obtained by the mold casting method, the short axis direction is 0.1 to 50 μm.
m, columnar crystals having a grain size of 0.1 to 100 μm in the major axis direction are known to exist, but the content of the crystals is small, which has a good effect on the magnet characteristics. Has not reached.

Furthermore, a rare earth metal element, cobalt and, if necessary, iron, copper and zirconium are added and dissolved in a crucible, and then a strip casting method in which twin rolls, single rolls, twin belts, etc. are combined. 0.01
A method for producing an alloy for a rare earth metal magnet, which is solidified to have a thickness of ~ 5 mm, has been proposed. In this method, an ingot having a uniform composition is obtained as compared with the die casting method, but the raw material components are rare earth metal elements, cobalt and, if necessary, iron,
Since the component is a combination of copper and zirconium, there is a problem that the improvement of the magnet performance by the strip casting method cannot be sufficiently obtained.

In addition, there are columnar crystal grains containing yttrium-containing rare earth elements, iron and / or cobalt, and boron as main components, and grain boundaries mainly containing a rare earth metal-rich phase. An alloy for magnet production having an average diameter of crystal grains (length in the major axis direction of the crystal) of 3 to 50 μm is crushed,
Shaped and sintered magnets have been proposed, and it is known that the alloy for producing magnets is produced by using a single roll or twin rolls of molten alloy while controlling the cooling rate. However, in the conventional method for producing an alloy for magnet production in which only the cooling rate is controlled by using a single roll or twin rolls, it is difficult to set the length of the columnar crystal grains in the major axis direction to a length exceeding 100 μm. When the length of such columnar crystal grains in the major axis direction is short, that is, the average diameter of the columnar crystal grains is 3 to 50.
If it is μm, there is a drawback that the performance of the anisotropic permanent magnet is inferior.

Further, in the case of producing a magnet, even when a magnet-forming alloy powder of one composition is magnetic field molded and sintered, a compound having a low melting point or a compound acting as a sintering aid is finely dispersed in the grain boundaries. If it does not exist in such a form, sintering does not proceed and a good sintered body cannot be obtained in many cases.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a permanent magnet which is easy to grind at the time of manufacture, has excellent magnet characteristics such as residual magnetic flux density and coercive force, and exhibits particularly excellent anisotropic characteristics. Especially.

Another object of the present invention is to provide a permanent magnet which has good sintering during production and exhibits excellent residual magnetic flux density, coercive force and the like.

[0008]

According to the present invention, 25 to 31% by weight of rare earth metal and 0.5 to 1.5% by weight of boron are used.
The alloy melt containing iron and iron is supercooled by a single roll method at a supercooling degree of 50 to 500 ° C. and a cooling rate of more than 500 ° C./sec.
90% by volume or more of columnar crystals having a columnar crystal grain diameter of 0.1 to 50 μm in the minor axis direction and 100 μm in the major axis direction and 300 μm or less obtained by solidifying uniformly under cooling conditions of 000 ° C./sec or less Provided is a permanent magnet characterized by crushing, shaping, and sintering a raw material component containing an alloy ingot as a main component.

The present invention will be described in more detail below. The permanent magnet of the present invention is a magnet obtained by crushing, molding, and sintering a raw material component whose main component is an alloy ingot synthesized by a specific manufacturing method, and shows excellent anisotropy, and has a conventional cooling rate. It has a higher degree of anisotropy and a better residual magnetic flux density and coercive force than a magnet using an alloy ingot having a columnar crystal with controlled C as a raw material.

The composition of the alloy melt for producing the alloy ingot of the essential component used in the present invention is rare earth metal 25-31.
% By weight, 0.5 to 1.5% by weight of boron and iron as essential components. The rare earth metal is not particularly limited, but preferred examples thereof include lanthanum, cerium, praseodymium, neodymium, yttrium, dysprosium, misch metal, and mixtures thereof. When the content of the rare earth metal is less than 25% by weight, an iron-rich phase such as α-iron phase is precipitated in the obtained alloy ingot, which adversely affects the pulverization step described later. When it exceeds 31% by weight, the residual magnetic flux density is lowered. On the other hand, when the content of boron is less than 0.5% by weight, high coercive force cannot be obtained, and when it exceeds 1.5% by weight, high residual magnetic flux density cannot be obtained. The iron content is 67.5 when the alloy melt contains no components other than the essential components.
The content is ˜74.5% by weight, but when components other than the essential components are contained, it is preferable to contain at least 37.5% by weight or more. That is, the content of the components other than the essential components is 3
It is preferably 0% by weight or less, particularly 10% by weight or less, and further preferably 6% by weight or less. Examples of components other than the essential components include cobalt, aluminum, chromium, manganese, magnesium, silicon, copper, carbon, tin, tungsten, vanadium, zirconium, titanium, molybdenum, niobium, gallium, and mixtures thereof. Particularly preferred is cobalt. In addition to these components, oxygen or the like may be contained as an unavoidable impurity or a trace component.

The alloy melt can be prepared by, for example, a vacuum melting method, a high frequency melting method, or the like, preferably using a crucible or the like in an inert gas atmosphere.

In the present invention, the alloy ingot which is the main component of the raw material components is manufactured by controlling the supercooling degree of the alloy melt to 50 to 500 ° C. Preferably its lower limit is to increase the ratio of the length of the obtained columnar crystal in the major axis direction to the length in the minor axis direction, improve the anisotropy degree, and further improve the dispersibility of the phase rich in rare earth metals. In order to improve the magnetic properties of the permanent magnet obtained as described above, it is preferable to control the temperature to 100 ° C., while the upper limit is the length of the obtained columnar crystal in the minor axis direction of 0.1 μm.
m or more, and the temperature is controlled to 500 ° C. in order to improve the magnetic characteristics of the obtained permanent magnet. Then, the alloy melt having such a specific supercooling degree is cooled at a cooling rate of 500 ° C. by a single roll method.
/ Sec or more and 10000 ° C./sec or less, preferably 100
A target alloy ingot can be obtained by uniformly solidifying under a cooling condition of 0 to 5000 ° C./sec.

At this time, the degree of supercooling is a value of (melting point of alloy)-(actual temperature of alloy melt below melting point). More specifically, “supercooling” is the temperature at which the alloy melt does not actually solidify even when the alloy melt is cooled to reach the melting point of the alloy, and the temperature is further lowered. A fine solid phase in a material, that is, a phenomenon in which crystals are formed and solidification occurs for the first time, and the degree of subcooling is the value of the difference between the melting point of the alloy and the actual temperature of the alloy melt below the melting point as described above. In the present invention, the difference, that is, the degree of supercooling of the alloy melt is 5
Control the cooling rate in the range of 0-500 ° C and 500
To obtain a novel alloy ingot containing at least 90% by volume of crystals having a crystal grain size in a specific range to be described later, which has not been known at all, by controlling the temperature to exceed 10 ° C / sec and 10,000 ° C / sec or less. You can To control the degree of supercooling of the alloy melt to the aforementioned specific temperature, for example, while controlling the temperature of the alloy melt prepared using the aforementioned crucible,
It can be controlled by appropriately adjusting the time, speed, etc. until it is introduced into a single roll for solidification.

In order to solidify the alloy melt controlled to a specific degree of supercooling by the single roll method at the specific cooling rate, for example, the rotation speed of the roll, the surface temperature, the ambient temperature, or the alloy melt is used. It can be carried out by a method of controlling the thickness of the alloy ingot obtained by adjusting the amount supplied to the roll. The reason why the single roll method is adopted is that, in the twin roll method, the rotating disk method, etc., it is difficult to control the crystal growth direction and the cooling rate, the desired crystal structure cannot be obtained, and the durability of the apparatus itself is not obtained. In addition, the alloy roll is controlled by the specific supercooling degree according to the single roll method, and it is easy to set conditions for continuously solidifying at the specific cooling rate. . The thickness of the alloy ingot is
In order to easily control the cooling rate, it is preferably 0.
It is desirable to set it in the range of 05 to 5 mm. 5mm thick
If it exceeds, it is difficult to manufacture an alloy ingot having a desired crystal structure described later, which is not preferable.

The alloy ingot obtained by the above-mentioned method is
Minor axis direction 0.1 to 50 μm, preferably 1 to 20 μm,
It contains 90% by volume or more, preferably 98% by volume or more of columnar crystals having a columnar crystal grain size of more than 100 μm in the major axis direction, preferably more than 150 μm and 300 μm or less, preferably 250 μm or less. In particular, it is preferable that α-Fe and / or γ-Fe which are usually contained as peritectic nuclei in the main phase crystal grains are not contained at all. When the α-Fe and / or γ-Fe is contained, it is preferable that the particle size of the α-Fe and / or γ-Fe is less than 10 μm and that the α-Fe and / or γ-Fe be finely dispersed. Such a crystal structure is
For example, it can be confirmed by an electron microscope photograph or the like.
When the length in the short axis direction and the length in the long axis direction are out of the above ranges, the magnetic properties of the obtained permanent magnet are deteriorated, and particularly when the length in the long axis direction is 100 μm or less, the aspect ratio of the columnar crystal is reduced. The ratio is reduced, the columnar crystals are similar to the granular crystals, the degree of anisotropy is reduced, and high magnetic characteristics cannot be obtained. Further, when the content ratio of the crystals having the specific crystal grain size is less than 90% by volume, excellent alloy properties cannot be imparted to the obtained alloy ingot. Furthermore, when the particle size of the α-Fe and / or γ-Fe is 10 μm or more and the particles are not finely dispersed, the particle size distribution becomes non-uniform during pulverization in the permanent magnet manufacturing process, and excellent. It is not preferable because the anisotropy cannot be obtained.

The content of the alloy ingot in the raw material components is not particularly limited as long as it is the main component, but in order to further improve the magnetic properties of the target permanent magnet, it is 70% with respect to the total amount of the raw material components. It is preferably 99.9% by volume.

Examples of raw material components other than the alloy ingots include metal ingots containing 31 to 100% by weight of a rare earth metal such as lanthanum, cerium, praseodymium, neodymium, yttrium, dysprosium, misch metal or a mixture thereof. be able to. The metal ingot may be an alloy containing 69 wt% or less of iron, cobalt, nickel, or a mixture thereof, in addition to the rare earth metal. Such a metal ingot can be prepared by, for example, a method similar to that of the alloy ingot as the main component, or by a known twin roll method, a metal casting method such as a rotating disk method, or the like. Can also be used. The content of the metal ingot is preferably 0.1 to 30% by weight based on the total amount of the raw material components in order to improve the magnetic properties of the permanent magnet obtained as compared with the case where the alloy ingot is used alone as the raw material component. . Three
When it exceeds 0% by weight, the magnet characteristics are deteriorated, which is not preferable.

The permanent magnet of the present invention is obtained by subjecting the raw material components including the alloy ingot to ordinary grinding, molding and sintering. The pulverization can be carried out by a known mechanical pulverization method or the like for the raw material components, preferably 250
After crushing to -24 mesh, further 10 μm or less, especially 2 to
It is desirable to finely pulverize to 3 μm, and it is also possible to separately finely pulverize and then mix and use for molding in the next step. When the metal ingot is contained as a raw material component, it is desirable that the alloy ingot, which is an essential component, be separately pulverized, then mixed, and further finely pulverized to the above range. At this time, since the alloy ingot has a specific polycrystalline structure and does not have peritectic nuclei or is finely dispersed, an alloy powder having a substantially uniform grain size can be easily prepared in a short time. Can get to
The amount of oxygen mixed during pulverization can be suppressed. Further, such fine pulverization can improve the magnet characteristics of the obtained permanent magnet.

The molding can be carried out by compression molding or the like in a usual magnetic field. At this time, the magnetic field strength is 12
The pressure is preferably 00 KAm to ¹ or more, particularly 1500 KAm to ¹ or more, and the molding pressure is preferably 100 to 200 MPa.

The sintering is not particularly limited and can be carried out by a known method, but preferably 1000 to 1200.
It can be carried out under an inert gas atmosphere or in a vacuum at 0.5 ° C. for 0.5 to 5 hours. At this time, the sintering can be satisfactorily progressed because the above-mentioned alloy powder is pulverized substantially uniformly, and the uniformity of the crystal grain size after sintering is also very good. Further, after sintering, heat treatment can be performed by a known method in order to further improve the magnetic characteristics. The heat treatment is
It can be preferably carried out at 400 to 600 ° C. for 0.5 to 5 hours.

[0021]

INDUSTRIAL APPLICABILITY The permanent magnet of the present invention is an alloy ingot having a novel crystal structure, which is prepared by controlling the degree of supercooling and the cooling rate of the alloy melt by a specific manufacturing method, particularly a single roll method. Is manufactured by using as an essential raw material ingredient,
Since the crushing step during manufacturing is easy and the progress of sintering can be sufficiently carried out, the magnet characteristics such as the residual magnetic flux density and the coercive force are excellent, and particularly excellent anisotropy is exhibited. Further, by using other metal ingots as the raw material component in addition to the alloy ingot, the permanent magnet itself is provided with further excellent magnetic characteristics. Therefore, it is expected to be used in fields where superior magnetic properties are required as compared with conventional permanent magnets.

[0022]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0023]

Example 1 A metal mixture containing a metal element having a composition of neodymium 30.8% by weight, boron 1.0% by weight, and iron 68.2% by weight was used in an argon gas atmosphere using an alumina crucible. It was made into a melt by the high frequency melting method. Then, after the temperature of the obtained melt was maintained at 1350 ° C., an alloy ingot for permanent magnet was obtained by the following method using the apparatus shown in FIG. The raw material composition is shown in Table 1. Figure 1
FIG. 1 is a schematic view for producing an alloy ingot for a permanent magnet by a strip casting method using a single roll, and 1 is a crucible containing a melt melted by the high frequency melting method. The melt 2 held at 1350 ° C. is continuously poured onto the tundish 3, and the roll 4 is rotated at a peripheral speed of about 3 m / s while adjusting the degree of supercooling to 200 ° C.
It is supplied above and solidified under cooling conditions of a cooling rate of 1000 ° C./second, and the melt 2 is continuously dropped in the rotation direction of the roll 4 to cast an alloy having a thickness of 0.2 to 0.5 mm. Chunk 5
Was manufactured. Table 2 shows the supercooling degree at the time of manufacturing the alloy ingot, the cooling rate, and the grain size of the crystal structure of the alloy ingot measured by an electron microscope.
Table 3 shows the structural features of the crystal structure observed with an electron microscope.
Shown in. In addition, the obtained alloy ingot has a minor axis direction of 0.1 to 5
The inclusion of 90% by volume or more of columnar crystals having a columnar crystal grain size of 0 μm, 100 μm in the major axis direction and 300 μm or less can be confirmed from the average diameter and standard deviation of the crystal structure in Table 2. Next, the obtained alloy ingot for permanent magnet was
It was ground to 0 to 24 mesh and further ground in alcohol to a size of about 3 μm. Next, the obtained fine powder was subjected to magnetic field pressing under the conditions of 150 MPa and 2400 KAm to ¹ and then sintered at 1040 ° C. for 2 hours to obtain 10 × 10 5.
A × 15 mm permanent magnet was obtained. Table 4 shows the magnetic properties of the obtained permanent magnets.

[0024]

Examples 2 and 3 A permanent magnet was prepared in the same manner as in Example 1 except that the raw material compositions shown in Table 1 were used and the supercooling degree and cooling rate shown in Table 2 were used. The crystal grain size of the alloy ingot is shown in Table 2,
Table 3 shows the structural characteristics of the crystal structure, and Table 4 shows the magnetic characteristics of the obtained permanent magnet. In addition, the obtained alloy ingot exceeds 0.1 to 50 μm in the minor axis direction and 100 μm in the major axis direction,
90 columnar crystals having a columnar grain size of 300 μm or less
It can be confirmed from the values of the average diameter and standard deviation of the crystal structure in Table 2 that the content is at least vol%.

[0025]

[Comparative Example 1] A metal mixture having the same composition as in Example 1 was melted by a high frequency melting method, and a thickness was 25 mm by a die casting method.
To obtain an alloy ingot for permanent magnet. The obtained alloy ingot was analyzed in the same manner as in Example 1 to manufacture a permanent magnet. The composition of the alloy ingot is shown in Table 1, the supercooling degree, the cooling rate and the crystal grain size of the alloy ingot are shown in Table 2, the structural characteristics of the crystal structure are shown in Table 3, and the magnetic properties of the obtained permanent magnet are shown. It shows in Table 4.

[0026]

Comparative Example 2 Using the raw material composition shown in Table 1, the melt temperature was 1200 ° C., and the roll peripheral speed was 0.01 m / s.
A permanent magnet was prepared in the same manner as in Example 1 except that the supercooling degree and the cooling rate shown in 1 were used. Table 2 shows the grain size of the alloy ingot.
Table 3 shows the structural characteristics of the crystal structure, and Table 4 shows the magnetic properties of the obtained permanent magnet.

[0027]

Comparative Example 3 Same as Example 1 except that the raw material composition shown in Table 1 was used, the melt temperature was 1600 ° C., the roll peripheral speed was 50 m / s, and the supercooling degree and cooling rate shown in Table 2 were used. A permanent magnet was prepared. Table 2 shows the crystal grain size of the alloy ingot, Table 3 shows the structural features of the crystal structure, and Table 4 shows the magnetic properties of the obtained permanent magnet.

[0028]

Comparative Example 4 An alloy ingot for permanent magnet was obtained in the same manner as in Comparative Example 1 except that the raw material composition shown in Table 1 was used, and further a permanent magnet was manufactured. The composition of the alloy ingot is shown in Table 1, the supercooling degree, the cooling rate and the crystal grain size of the alloy ingot are shown in Table 2, the structural characteristics of the crystal structure are shown in Table 3, and the magnetic properties of the obtained permanent magnet are shown. It shows in Table 4.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

[0033]

Example 4 Neodymium 28.0% by weight, boron 0.95
A metal mixture containing a metal element having a composition of 70% by weight of iron and 71.05% by weight of iron was melted by an induction melting method using an alumina crucible in an argon gas atmosphere. Then, the obtained melt was subjected to the single roll method in the same manner as in Example 1 to obtain an alloy ingot for a permanent magnet main phase with the supercooling degree and the cooling rate shown in Table 5. Neodymium 40.0% by weight,
A metal mixture containing a metal element having a composition of 1.5 wt% boron and 58.5 wt% iron was melted by an induction melting method using an alumina crucible in an argon gas atmosphere. Then, the obtained melt was subjected to the single roll method in the same manner as in Example 1 to obtain alloy ingots for permanent magnet sintering aids at the supercooling degrees and cooling rates shown in Table 6. The composition of the alloy ingot for permanent magnet main phase is shown in the upper part of the column of each example in Table 5, and the composition of the alloy ingot for permanent magnet sintering aid is shown in the lower part.
Next, the obtained alloy ingot for permanent magnet main phase and alloy ingot for permanent magnet sintering aid were separately pulverized to 250 to 24 mesh, and 83% by weight of permanent alloy main phase ingot and permanent alloy The alloy ingot for magnet sintering aid was weighed so as to be 17% by weight, mixed, and further pulverized in alcohol to about 3 μm. Then, the fine powder obtained was treated with 150MP
a, after magnetic field pressing under the condition of 2400 KAm ~ ¹ , 1
Sintering was performed at 040 ° C. for 2 hours to obtain a 10 × 10 × 15 mm permanent magnet. Table 6 shows the degree of supercooling at the time of producing the alloy ingot, the cooling rate, and the crystal grain size of the obtained alloy ingot, the structural features of the alloy ingot, the alloy ingot for the permanent magnet main phase, and the permanent magnet sintering aid. Table 7 shows the mixing ratio of the alloy ingot for chemicals, and Table 8 shows the magnetic properties of the permanent magnets. The obtained alloy ingot had a minor axis direction of 0.1.
The inclusion of 90% by volume or more of columnar crystals having a columnar crystal grain size of ˜50 μm, 100 μm in the major axis direction and 300 μm or less can be confirmed from the average diameter and standard deviation of the crystal structure in Table 6.

[0034]

Example 5 Using the compositions of the alloy ingot for permanent magnet main phase and the alloy ingot for permanent magnet sintering aid shown in Table 5, the supercooling degree and cooling rate shown in Table 6 and the permanent set shown in Table 7 were used. A permanent magnet was prepared in the same manner as in Example 4, except that the alloy ingot for the main magnetic phase and the alloy ingot for the permanent magnet sintering aid were used in the mixing ratio. Table 6 shows the degree of supercooling at the time of producing the alloy ingot, the cooling rate, and the crystal grain size of the obtained alloy ingot, the structural characteristics of the alloy ingot, the alloy ingot for the permanent magnet main phase, and the permanent magnet sintering aid. Table 7 shows the mixing ratio of the alloy ingot for chemicals, and Table 8 shows the magnetic properties of the permanent magnets. It should be noted that the obtained alloy ingot contains 90% by volume or more of columnar crystals having a columnar crystal grain size of 300 μm or less and exceeding 0.1 to 50 μm in the minor axis direction and 100 μm in the major axis direction. It can be confirmed from the average diameter of the crystal structure and the value of standard deviation.

[0035]

Examples 6 to 22 Using the composition of the alloy ingot for permanent magnet main phase and the alloy ingot for permanent magnet sintering aid shown in Table 5, the supercooling degree and cooling rate shown in Table 6 and the permanent magnet main Mixing of the alloy ingot for main phase and alloy ingot for permanent magnet sintering aid shown in Table 7 after separately pulverizing the alloy ingot for phase and the alloy ingot for permanent magnet sintering aid separately A permanent magnet was prepared in the same manner as in Example 4 except that the ratios were mixed and the magnetic field was formed. Table 6 shows the degree of supercooling at the time of producing the alloy ingot, the cooling rate, and the crystal grain size of the obtained alloy ingot, the structural characteristics of the alloy ingot, the alloy ingot for the permanent magnet main phase, and the permanent magnet sintering aid. Table 7 shows the mixing ratio of the alloy ingot for chemicals, and Table 8 shows the magnetic properties of the permanent magnets. The obtained alloy ingot contains 90% by volume or more of columnar crystals having a columnar crystal grain size of 300 μm or less and 0.1 μm to 50 μm in the minor axis direction and 100 μm in the major axis direction.
It can be confirmed from the average diameter and standard deviation of the crystal structure of.

[0036]

[Table 5]

[0037]

[Table 6]

[0038]

[Table 7]

[0039]

[Table 8]

[Brief description of drawings]

FIG. 1 is a schematic view of manufacturing an alloy ingot for a permanent magnet by a strip casting method using a single roll used in Examples.

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[Procedure amendment]

[Submission date] May 24, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Examples of raw material components other than the alloy ingots include metal ingots containing 31 to 100% by weight of a rare earth metal such as lanthanum, cerium, praseodymium, neodymium, yttrium, dysprosium, misch metal or a mixture thereof. be able to. The metal ingot may be an alloy containing 69 wt% or less of iron, cobalt, nickel, or a mixture thereof, in addition to the rare earth metal. Such a metal ingot can be prepared by, for example, a method similar to that of the alloy ingot as the main component, or by a known twin roll method, a metal casting method such as a rotating disk method, or the like. Can also be used. The content of the metal ingot is preferably 0.1 to 30 % by volume with respect to the total amount of the raw material components in order to improve the magnetic properties of the permanent magnet obtained as compared with the case where the alloy ingot is used alone as the raw material component. . Three
If it exceeds 0 % by volume , the magnet characteristics are deteriorated, which is not preferable.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01F 1/053

Claims (6)

[Claims] 1. An alloy melt containing 25 to 31% by weight of a rare earth metal, 0.5 to 1.5% by weight of boron, and iron is cooled by a single roll method at a supercooling degree of 50 to 500 ° C. and a cooling rate. Fifty
It has a columnar crystal grain size of 0.1 to 50 μm in the minor axis direction, 100 μm in the major axis direction, and 300 μm or less in the major axis direction obtained by uniformly solidifying under cooling conditions of more than 0 ° C./second and 10,000 ° C./second or less. A permanent magnet characterized in that a raw material component containing, as a main component, an alloy ingot containing 90% by volume or more of columnar crystals is crushed, molded and sintered. 2. A grain size of 1 in the main phase crystal grains of the alloy ingot.
The permanent magnet according to claim 1, wherein peritectic nuclei of less than 0 µm selected from the group consisting of α-Fe, γ-Fe, and a mixture thereof are finely dispersed. 3. The permanent magnet according to claim 1, wherein the content of the alloy ingot in the raw material components is 70 to 99.9% by volume. 4. The permanent magnet according to claim 1, wherein the raw material component further contains a metal ingot containing 31 to 100% by weight of a rare earth metal. 5. The permanent magnet according to claim 4, wherein the metal ingot contains a transition metal selected from the group consisting of iron, cobalt, nickel and mixtures thereof. 6. The permanent magnet according to claim 4, wherein the content of the metal ingot is 0.1 to 30% by volume with respect to the total amount of raw material components.