JPH09232173A - Manufacture of rare earth magnet, and rare earth magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet with excellent magnetic characteristics by restricting the oxidation of a rare earth element. SOLUTION: This rare earth magnet contains 26.7 to 32wt.% of R (R is 1 kind or 2 kinds or more among rare earth elements containing Y), 0.9 to 2.0wt.% of B, and 0.1 to 3.0wt.% of M (M is at least 1 kind or more of Ga, Al and Cu), the remainder comprises an alloy A with R2 Fe14 B containing Fe as main body and an alloy B comprising 35 to 70wt.% of R, 5 to 50wt.% of Co, 0.1 to 3.0wt.% of M with the remainder consisting of Fe, with which the coarse powder of 1 to 30wt.% of B alloy is mixed for the coarse powder of 70 to 99wt.% of alloy A as mixed coarse powder raw material. This pulverized in a inert gas practically having 0% of oxygen, fine powder is directly recovered in a solvent containing mineral oil, synthesized oil, vegetable oil of their mixture in the atmosphere of inert gas and is turned into slurry, the raw material of the slurry is wet formed in a magnetic field, a molded body is desolvent-treated in vacuum and then sintering is performed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical pickup for CD, VCM, various motors (servo motor, EV).
Etc.) for R-Fe-B system (R is one or more kinds of rare earth elements including Y) rare earth permanent magnets.

[0002]

2. Description of the Related Art Nd-Fe-B rare-earth permanent magnets, which are relatively abundant and inexpensive in resources and contain Nd and Fe as main components, have increased year by year because of their extremely excellent magnetic properties. It now accounts for the majority of the rare earth magnet market. Along with this, research and development are also active, and in particular, a method of mixing two metal powders having different compositions (hereinafter referred to as a blending method) has a high magnetic property by controlling a phase in the two metal powders. Many methods have been proposed because the characteristics can be obtained. When mixing two alloys having different compositions, a method of mixing a main phase forming alloy having a composition close to that of the main phase R ₂ T ₁₄ B phase and an R-rich second phase forming alloy is often used. For example, in JP-A-63-93841, the R ₂ T ₁₄ B phase (R is at least one rare earth element including Y, T is Fe or Fe)
(Mixture of Co) and R-X alloy (X
Is Fe or Fe and B, Al, Ti, V, Co, Zr,
There has been proposed a method for producing a magnet alloy by mixing an alloy obtained by quenching a molten metal composed of at least one kind of mixture of Nb and Mo). Further, for example, in JP-A-5-175026 and JP-A-5-175027, alloy powder mainly composed of R ₂ T ₁₄ B phase and Mg
A magnet alloy is obtained by mixing, molding, and sintering intermetallic compound powders having a crystal type such as Cu ₂ type, PuNi ₃ type, and CaZn ₅ type. In these methods, by using two metals having different compositions, the pulverizability, the sinterability and the structure in the magnet alloy are improved, and a single alloy is used as a starting material (hereinafter referred to as a single method). The magnetic characteristics can be greatly improved in comparison with.

[0003]

In the above-mentioned blending method, the second phase forming alloy is produced by a liquid quenching method and is made into an alloy containing an intermetallic compound of a rare earth, thereby reducing an increase in the amount of oxygen. Is characteristic. However, the second phase forming alloy contains a large amount of chemically active rare earth elements, and in order to obtain a practically effective coercive force as a magnet alloy, the main phase forming alloy and the second phase forming alloy 2 to 10μ
Since it needs to be pulverized to a fine powder of about m, the usual method causes severe oxidation and may even cause a fire. The oxidized rare earth element does not serve as a liquid phase during sintering,
Does not contribute to improving the density of the magnet alloy. Therefore, it was necessary to predict the amount of rare earth to be oxidized and to preliminarily contain the raw alloy with a larger amount of rare earth than required. In addition, the oxidized rare earth element remains in the magnet alloy after sintering, and lowers the volume ratio of the main phase R ₂ T ₁₄ B phase that expresses effective magnetization. Only a small residual magnetic flux density was obtained. It is an object of the present invention to provide a permanent magnet that suppresses the oxidation of rare earth elements and has excellent magnetic properties.

[0004]

Means for Solving the Problems The present inventors have studied a method for minimizing the oxidation during the fine pulverization and carried out fine pulverization in an inert gas having an oxygen content of substantially 0% to We have found a method to recover fine powder directly in a solvent in an active gas atmosphere. Furthermore, by using this method, we were able to find a composition that expresses the true potential of the blending method. In the present invention, the A alloy has an R content of 26.7 to 32 wt% (R is one or more kinds of rare earth elements including Y) and a B content of 0.9 to.
An alloy mainly composed of R ₂ Fe ₁₄ B containing 2.0 wt% and M (M is at least one of Ga, Al, and Cu) of 0.1 to 3.0 wt% and the balance Fe. Alloy 35 to 70 wt% R, Co 5 to 50 wt%,
After making 0.1 to 3.0 wt% of M and an alloy consisting of Fe as the balance, 70 to 99 wt% of coarse powder of A alloy and 1 to 30 wt% of coarse powder of B alloy to form raw material coarse powder, Finely pulverize this in an inert gas containing substantially 0% oxygen,
Fine powder is directly recovered in a solvent consisting of mineral oil, synthetic oil, vegetable oil or a mixture thereof in an inert gas atmosphere to form a slurry, and the slurry-like raw material is wet-molded in a magnetic field, and the molded body is vacuumed. Desolvation treatment in followed by sintering, R: 27
.About.31 wt%, B: 0.5 to 2.0 wt%, Co: 0.
5-5 wt%, M: 0.01-1.0 wt%, O: 0.
25 wt% or less, N: 0.02 to 0.15 wt%, C:
This is a method for producing a rare earth magnet having a composition of 0.15 wt% or less and the balance being Fe.

In the present invention, alloys A and B having different compositions are used.
Use an alloy. The alloys A and B may be cast by arc melting, high frequency melting, or the like, or a thin ribbon alloy of 0.1 to 0.4 mm obtained by rapidly cooling the molten metal may be used. A
The alloy is mainly composed of the R ₂ Fe ₁₄ B phase (R is one or more rare earth elements including Y). The amount of R in the A alloy is 26.7.
˜32 wt%. If the amount of R is 26.7 wt% or less, the R ₂ Fe ₁₄ B phase is not sufficiently formed and α-Fe having soft magnetic properties is precipitated, and if it is 32 wt% or more, the R-rich phase containing a large amount of R is present. Increase, the amount of oxygen increases. Also,
The amount of B in the A alloy is preferably 0.9 to 2.0 wt%, B
If the amount is 0.9 wt% or less, the R ₂ Fe ₁₄ B phase is not sufficiently generated, and the R ₂ Fe ₁₇ phase, which is a soft magnetic material, is precipitated,
It becomes a factor that deteriorates the magnetic characteristics. Furthermore, M (M is G
The amount of at least one of a, Al and Cu) is
It is 0.1 to 3.0 wt%. Although these elements contribute to the improvement of the coercive force, a sufficient coercive force cannot be obtained at 0.1 wt% or less, and the residual magnetic flux density is reduced at 3.0 wt% or more. The alloy A produced in this way is 600-
Heat treatment in the temperature range of 1500 ° C for 1 to 50 hours, α-F
It is preferable to reduce e and R ₂ Fe ₁₇ phase.

The alloy B has a larger amount of R than the alloy A and is mainly composed of the R ₁ T ₂ phase (T is one of Fe and Co or 2
Seed), R ₁ T ₃ phase, R ₂ T _{17, and the} like. The R content of the B alloy is 35 to 70 wt%. R amount is 35 wt%
In the following, a soft magnetic phase such as α-Fe occurs. On the other hand, if the R content is 70 wt% or more, an R-rich phase containing a large amount of R in the alloy is generated and is easily oxidized during pulverization, and further melts at a low temperature during sintering, which causes abnormal grain growth.
Further, the amount of Co added to the B alloy is 5 to 50 wt%.
When Co is added to the B alloy, it improves the oxidation resistance of the B alloy, which is easily oxidized. Therefore, it is desirable to add Co to the B alloy. Further, Co is contained in the grain boundaries in the sintered magnet and contributes to the improvement of corrosion resistance, and also diffuses into the main phase to raise the Curie point and improve the heat resistance of the magnet alloy, but the amount added to the B alloy. Is less than 5 wt%, these effects are insufficient,
If it is more than 50 wt%, the saturation magnetic flux density will decrease. The M content of the B alloy is 0.1 to 3.0 wt%. 0.
If it is less than 1 wt%, a sufficient coercive force cannot be obtained.
%, The residual magnetic flux density decreases.

The alloys A and B are roughly pulverized by hydrogen treatment and bantam milling to obtain coarse powder. Next, the A alloy coarse powder is 99 to 70 wt% and the B alloy coarse powder is 1 to 30 w
It is blended so as to be t% and uniformly mixed by a V-type mixer, a ball mill or the like. At this time, if the B alloy coarse powder is less than 1 wt%, the sinterability will be poor and the sintered body density will not increase, so sufficient magnet characteristics cannot be obtained. On the other hand, if the content is more than 30 wt%, R becomes excessive, so that only a small residual magnetic flux density can be obtained. The coarse powder after mixing has R of 27 to 31w.
t%, B 0.5 to 2.0 wt%, Co 0.5 to 5 w
t% and M are contained in an amount of 0.01 to 1.0 wt%.

The mixed raw material powder of the A alloy coarse powder and the B alloy coarse powder thus obtained is crushed by a pulverizer such as a jet mill in an inert gas atmosphere having an oxygen content of substantially 0 wt%. Finely pulverize to obtain fine powder having an average particle size of 2 to 10 μm. When recovering fine powder, a container filled with a solvent such as mineral oil, vegetable oil, or synthetic oil is installed at the fine powder recovery port of a jet mill or the like, and the fine powder is directly recovered in an inert gas atmosphere. The slurry-like raw material thus obtained is wet-molded in a magnetic field to obtain a molded body. The molded body is heated to a temperature of about 100 to 300 ° C. in a vacuum of about 5 × 10 ^-2 torr to remove the solvent contained in the molded body. Then, subsequently, the temperature of the vacuum furnace is raised to about 1000 to 1200 ° C., and 10
Sintering is performed under a vacuum degree of ^-3 to 10 ^-5 torr.

The sintered body obtained through these steps is
R: 27-31 wt%, B: 0.5-2.0 wt%, C
o: 0.5-5 wt%, M: 0.01-1.0 wt%,
O: 0.25 wt% or less, N: 0.02-0.15 wt
%, C: 0.15 wt% or less. R, B,
The amounts of Co and Fe are based on the composition adjustment at the time of raw material of coarse powder. O, N, and C are contained as impurities in the raw material alloy, or are mixed from the atmosphere or solvent during coarse pulverization or heating. However, these elements are contained in the magnet alloy in the form of Nd ₂ O ₃ ,
By making compounds such as Nd ₂ C ₃ and NdN to lower the volume ratio of the main phase,
In order to reduce the amount of R acting as a liquid phase during sintering and inhibit sintering, O is 0.25 wt% or less and N is 0.02 to 0.02 wt%.
0.15 wt% and C: 0.15 wt% or less. By subjecting the thus obtained sintered body to a two-step or three-step heat treatment at a temperature equal to or lower than the sintering temperature, a target magnet having excellent magnetic properties can be obtained. In the rare earth magnet of the present invention, R is 27 to 31 wt%
And If R is less than 27 wt%, the liquid phase required for sintering cannot be obtained and the density of the sintered body becomes low, so that the magnetic properties deteriorate. When R exceeds 31 wt%, R becomes excessive and only a small residual magnetic flux density can be obtained. When B is less than 0.5 wt%, the R ₂ T ₁₄ B phase is not sufficiently formed, so that only a small residual magnetic flux density is obtained, and when it is more than 2.0 wt%, a non-magnetic B rich phase is generated and the residual magnetic flux density is lowered. For,
B 0.5 to 2.0 wt%. Co is added to improve the corrosion resistance and heat resistance of the magnet alloy, but if it is less than 0.5 wt%, the corrosion resistance and heat resistance are not sufficient, and if it exceeds 5 wt%, the residual magnetic flux density is greatly reduced. M is Al,
One or more elements selected from Cu and Ga are added to improve coercive force, but 0.01 wt%
If it is less than 1.0 wt%, a sufficient coercive force cannot be obtained, and if it is more than 1.0 wt%, the volume fraction of the R ₂ T ₁₄ B phase is lowered and the residual magnetic flux density is lowered.

The reason why high magnetic characteristics can be obtained by the present invention will be described. In the present invention, since wet recovery and wet molding can prevent oxidation after fine pulverization, the amount of rare earth in the raw material composition can be reduced and a high residual magnetic flux density can be obtained. Furthermore, since the compositions and structures of the alloys A and B are set as optimum for the manufacturing method according to the present invention, sinterability and the like can be improved,
Even if an element such as Nb which prevents grain growth is not used, the structure in the magnet alloy can be optimized. Furthermore, Co,
By adding an additive element such as Dy to the B alloy, the element distribution can be controlled. That is, by the production method according to the present invention, it is possible to obtain a magnet alloy having a low oxygen content and excellent magnetic properties by sufficiently drawing out the potential of the blending method. The above-mentioned inert gas having an oxygen concentration of substantially 0 wt% is, for example, a production type jet mill crusher having an ability to finely pulverize R-Fe-B based raw material coarse powder by about 10 kg / Hr. In the case of, the oxygen concentration in the inert gas is 0.01 wt% in percentage.
% Or less, more preferably 0.005 wt% or less, and further preferably 0.002 wt% or less, an inert gas atmosphere.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples, but the contents of the present invention are not limited thereto. (Example 1) Nd, Pr, B, Ga having a purity of 95% or more,
Predetermined amounts of Cu and Fe were melted by high frequency melting in an Ar gas atmosphere, the alloy melt was poured into a copper single roll in the same Ar gas atmosphere, and the composition shown in Table 1 was obtained by a so-called strip casting method. Alloy 1 (A alloy) was manufactured. The obtained alloy 1 is in the form of a thin plate and has a plate thickness of 0.1 to 10.
0.3 mm. Further, alloy 1 was placed in a vacuum furnace and heat-treated at 1000 ° C. for 4 hours under the conditions of 5 × 10 ^-2 Torr. Nd, Pr, Dy, C with a purity of 95% or more
O was melted by high frequency melting in an Ar gas atmosphere and cast to prepare an alloy 2 (B alloy) having the composition shown in Table 1.
The alloys 1 and 2 thus obtained were each occluded with hydrogen in a furnace with air removed, and then heated to 500 ° C. while being evacuated, cooled, and then subjected to a coarse pulverizer. , A coarse powder of 32 mesh or less.
90 wt% of the obtained coarse powder of alloy 1 was uniformly mixed with 10 wt% of the coarse powder of alloy 2 by a V-type mixer to obtain a mixed raw material powder. After charging this mixed raw material powder into a jet mill, the inside of the jet mill was replaced with N ₂ gas to an oxygen concentration of 0.001 wt%. Mineral oil (made by Idemitsu Kosan, product name Idemitsu Super Sol PA-
A container filled with 30) was installed and directly recovered in an N ₂ gas atmosphere. The average particle size of the fine powder was 4.5 μm.
This raw material slurry was placed in a mold cavity at 12 kOe.
Wet molding was performed at a molding pressure of 0.8 ton / cm ² while applying the magnetic field of. The method of applying the orientation magnetic field is perpendicular to the molding direction. In addition, a solvent discharge hole is provided on the upper punch of the mold,
At the time of molding, a cloth filter having a thickness of 1 mm was applied to the upper punch surface and used. The molded body is heated in a vacuum of 5 × 10 ⁻² torr for 200 × 1 hour to remove the contained mineral oil, and then heated to 1070 ° C. at a heating rate of 15 ° C./min under the condition of 5 × 10 ⁻⁵ torr. The temperature was raised and the temperature was maintained for 2 hours for sintering. Further, this sintered body was heated at 900 ° C. in an Ar atmosphere.
Heat treatment of 2 hours and 500 ° C x 1 hour each was performed once, and Table 2
Sample No. A rare earth magnet having the composition shown as 1 was obtained. The oxygen content of the obtained rare earth magnet was 0.096 wt%. This sample No. The magnetic properties of No. 1 were measured and shown in Table 3.
Br = 14.1 kG, iHc = 16.3 kOe, (B
H) max = 47.5 MGOe, which is a good magnetic characteristic.

(Comparative Example 1) Alloy 1 and alloy 2 were roughly crushed in the same manner as in Example 1 and mixed at a mixing ratio of 90:10 to prepare raw material coarse powder. Further, fine pulverization was performed in a jet mill in a N ₂ stream in the same manner as in Example 1, but an empty container was prepared at the recovery port, and recovery was performed in a N ₂ atmosphere (dry method). When recovering by such a method, if the oxygen concentration in the jet mill is too low, ignition will occur when the fine powder is released into the atmosphere, so that the oxygen concentration in the N ₂ stream will be 0.1 wt%. Was introduced into the crushing chamber. The average particle size of the fine powder was 4.5 μm. The dry fine powder thus obtained was molded in a mold cavity at a molding pressure of 0.8 ton / cm ² while applying a magnetic field of 12 kOe. The method of applying the orientation magnetic field is perpendicular to the molding direction. The compact was sintered by holding it at 1070 ° C. for 2 hours in a vacuum of 5 × 10 ^-5 torr. The sintered body thus obtained was subjected to a two-step heat treatment under the same conditions as in Example 1 and No. 2 in Table 2 was used. A rare earth permanent magnet having the composition shown as 2 was obtained. Sample No. The composition of 2 is O0.612%, C
No. except that it is 0.045%. It is almost the same as 1. The magnetic characteristics of this sample were measured. As shown in Table 3, Br = 13.5 kOe, iHc = 14.3 kOe,
(BH) max = 43.3MGOe, and the magnetic characteristics were larger than those in Example 1 and deteriorated. This is because the fine powder was recovered by the dry method, so that the fine powder was oxidized, and the liquid phase that worked effectively during sintering was. It is considered that sintering was not performed smoothly due to the decrease, and the density of the sintered body decreased. Thus, it can be seen that the dry method using the blending method does not exhibit its potential sufficiently, and that sufficient magnetic characteristics can be obtained by using the production method of the present invention in which wet recovery is performed with low oxygen.

Comparative Example 2 A rare earth magnet having the same composition as in Example 1 was produced by the single method. A predetermined amount of Nd, Pr, Dy, B, Co, Ga, Cu, and Fe having a purity of 95% or more was weighed, and by a strip casting method under the same conditions as in Example 1, Nd was 27.9% by weight and Pr0. .46
%, Dy1.5%, B1.05%, Co2.0%, Ga
A raw material alloy having a composition of 0.08%, Cu 0.10% and balance Fe was prepared. Further, this was roughly crushed under the same conditions as in Example 1 and crushed in an N ₂ atmosphere with an oxygen concentration of 0.001 wt%, and subjected to wet recovery, wet molding, desolvation, sintering, and heat treatment. ． It was set to 3. The composition was almost the same as that of Comparative Example 1 except that O was 0.170 wt% as shown in Table 1. The magnetic properties of this sample are shown in Table 3.
, Br = 13.9 kGOe, iHc = 15.
0 kOe, (BH) max = 46.0 MGOe,
The result was lower than that of Example 1. This shows that the blend method is more advantageous than the single method for improving the magnetic properties.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

[Table 3]

(Example 2) Nd and P having a purity of 95% or more
A predetermined amount of r, B, Ga, Cu, Fe was weighed and melted by high frequency melting in an Ar gas atmosphere.
An alloy 3 (A alloy) having the composition shown in Table 4 was prepared by pouring the copper single roll in an r gas atmosphere and using a so-called strip casting method. The alloy 3 obtained was in the form of a thin plate and had a plate thickness of 0.1 to 0.3 mm. Further, alloy 3 was charged into a vacuum furnace, and it was heated to 10 under the condition of 5 × 10 ^-2 Torr.
Heat treatment was performed at 00 ° C. for 4 hours. N with a purity of 95% or more
Alloy 4 (B alloy) having the composition shown in Table 4 was produced by melting d, Pr, Dy, and Co by high frequency melting in an Ar gas atmosphere and casting. The alloy 3 and the alloy 4 thus obtained were respectively occluded with hydrogen in a furnace with air removed, and then heated to 500 ° C. while being evacuated, cooled, and then subjected to a coarse pulverizer. , A coarse powder of 32 mesh or less. 15 wt% of the coarse powder of Alloy 4 was mixed uniformly with 85 wt% of the coarse powder of Alloy 3 by a V-type mixer to obtain a mixed raw material powder. After charging the mixed raw material powder into the jet mill, the inside of the jet mill was replaced with N ₂ gas,
The oxygen concentration was 0.001 wt%. A container filled with mineral oil (made by Idemitsu Kosan Co., Ltd., product name Idemitsu Supersol PA-30) was installed at the fine powder recovery port of the jet mill, and the powder was directly recovered in an N ₂ gas atmosphere. The average particle size of the fine powder is 4.1 μm
Met. This raw material slurry is placed in the mold cavity 1
Wet molding was performed at a molding pressure of 0.8 ton / cm ² while applying a magnetic field of 2 kOe. The method of applying the orientation magnetic field is perpendicular to the molding direction. A solvent discharge hole was provided in the upper punch of the die, and a 1 mm-thick cloth filter was applied to the upper punch surface during molding. Molded body is 5 × 10 ^-2 torr
To remove the contained mineral oil by heating in a vacuum of 200 × 1 hour, and then heat up to 1080 ° C. at a heating rate of 15 ° C./min under the condition of 5 × 10 ⁻⁵ torr, and at that temperature for 2 hours Hold and sinter. Furthermore, this sintered body is heat-treated at 900 ° C. for 2 hours and 4800 ° C. for 1 hour in Ar atmosphere for 1 time each.
The operation was repeated to obtain a rare earth magnet. This was designated as Sample No. 4, and the composition thereof is shown in Table 5. The amount of oxygen in the sintered body is 0.09
It was 4 wt%. Further, the magnetic characteristics of this sample were measured, and shown in Table 6, Br = 12.6 kOe, iHc = 26.
Good magnetic characteristics of 2 kOe and (BH) max = 37.7 MGOe could be obtained.

Comparative Example 3 Alloys 3 and 4 were roughly crushed in the same manner as in Example 2 and mixed at a mixing ratio of 85:15 to prepare raw material coarse powder. Further, fine pulverization was performed in a jet mill in an N ₂ stream in the same manner as in Example 2, but an empty container was prepared at the recovery port, and recovery was performed in an N ₂ atmosphere (dry method). When recovering by such a method, if the oxygen concentration in the jet mill is too low, ignition occurs when the fine powder is released into the atmosphere, so that the oxygen concentration in the N ₂ stream should be 0.1 wt%. Was introduced into the crushing chamber. The average particle size of the fine powder was 4.1 μm. The dry fine powder thus obtained was molded in a mold cavity at a molding pressure of 0.8 ton / cm ² while applying a magnetic field of 12 kOe. The method of applying the orientation magnetic field is perpendicular to the molding direction. This molded body is heated at 1080 ° C. for 2 times in a vacuum of 5 × 10 ⁻⁵ torr.
Sintered by holding for a time. The thus obtained sintered body was subjected to a two-step heat treatment under the same conditions as in Example 1, and this sample was It was set to 5. The composition is shown in Table 5, except for the amounts of O and C. It is almost the same as 4. The oxygen content of this sample was 0.612 wt%. The magnetic characteristics of this sample were measured. As shown in Table 6, Br = 12.
1 kOe, iHc = 24.1 kOe, (BH) max
= 34.9 MGOe, and the magnetic characteristics were significantly lower than in Example 2. It is considered that this is because the fine powder was oxidized by the dry method, the fine powder was oxidized, and the liquid phase that worked effectively at the time of sintering was reduced, so that the sintering was not performed smoothly and the density of the sintered body was lowered. As described above, it is understood that the conventional method using the blending method does not sufficiently exhibit its potential, and that sufficient magnetic characteristics can be obtained by using the present invention in which the wet recovery is performed with low oxygen.

Comparative Example 4 A rare earth magnet was produced by the single method so that the final composition was the same as that of Comparative Example 3. Nd, Pr, Dy, B, Co, Ga, C with a purity of 95% or more
Predetermined amounts of u and Fe were measured by a strip casting method under the same conditions as in Example 2, and in% by weight, Nd 23.8%, P
r0.42%, Dy6.0%, B1.00%, Co3.
A raw material alloy having a composition of 0%, Ga 0.09%, Cu 0.09% and the balance Fe was prepared. Further, this was coarsely pulverized under the same conditions as in Example 2, and the oxygen concentration was 0.00
Sample No. 1 was crushed in a 1 wt% N ₂ atmosphere, wet recovery, wet molding, solvent removal, sintering, and heat treatment were performed. 6
I decided. As shown in Table 5, the composition has an oxygen content of 0.
It was almost the same as Comparative Example 3 except that it was 182 wt%. As shown in Table 6, the magnetic characteristics of this sample are Br = 1.
2.4 kGOe, iHc = 25.0 kOe, (BH) m
ax = 36.5 MGOe, which was lower than that of Example 2. This shows that the blend method is more advantageous than the single method for improving the magnetic properties.

[0020]

[Table 4]

[0021]

[Table 5]

[0022]

[Table 6]

According to the present invention, a permanent magnet having a small amount of oxygen and excellent magnetic properties can be obtained.

Claims (2)

[Claims] 1. R is 26.7 to 32 wt% (R is one or more rare earth elements including Y) and B is 0.9.
-2.0 wt%, M (M is at least one or more of Ga, Al, Cu) 0.1-3.0 wt% and the balance is A 2 alloy mainly composed of R ₂ Fe ₁₄ B , R 35 to 70 wt%, Co 5 to 50 wt%, M 0.1
A B alloy containing 3.0 wt% to the rest of Fe,
Coarse powder of alloy 70 to 99 wt% to coarse powder of B alloy 1 to
After mixing 30 wt% into a mixed raw material powder, it is finely pulverized in an inert gas with an oxygen content of substantially 0%, and mineral oil, synthetic oil, vegetable oil or these is pulverized in an inert gas atmosphere. Fine powder is directly recovered in a solvent consisting of a mixture of the above to form a slurry, the slurry-like raw material is wet-molded in a magnetic field, the molded body is subjected to desolvation treatment in a vacuum, and then sintered,
R: 27-31 wt%, B: 0.5-2.0 wt%, C
o: 0.5-5 wt%, M: 0.01-1.0 wt%,
O: 0.25 wt% or less, N: 0.02-0.15 wt
%, C: 0.15 wt% or less, and a method for producing a rare earth magnet alloy, characterized in that a rare earth magnet having a composition of balance Fe is obtained. 2. R: 27-31 wt%, B: 0.5-
2.0 wt%, Co: 0.5-5 wt%, M: 0.01
~ 1.0 wt%, O: 0.25 wt% or less, N: 0.0
2 to 0.15 wt%, C: 0.15 wt% or less, balance F
A rare earth magnet obtained by the manufacturing method according to claim 1, which has a composition of e and has a coercive force of 13 kOe or more.