JPH09148163A - Manufacture of r-t-b antisotropic bonded magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an R-T-B anisotropic bonded magnet which is lessened in change of characteristics with time and possessed of a demagnetizing curve of excellent angularity to be obtained through a hydrogenation.recrystallization treatment method. SOLUTION: When an R-T-B alloy ingot is subjected to a hydrogenation.recrystallization treatment, it rises in temperature in a hydrogen atmosphere and changes in alloy configuration through hydrogen storage disintegration or so-called hydrogen disintegration, alloy powder obtained through a hydrogen storage disintegration method is molded into a body, and the molded body is subjected to a hydrogenation.recrystallization treatment, whereby alloy powder more lessened than usual in change of characteristics with time can be obtained. When material powder of small coercive force before it is subjected to a hydrogenation.recrystallization treatment is molded in a magnetic field, the molded body which is far more excellent in degree of orientation than a molded body which is formed of allay powder that is subjected to a hydrogenation.recrystallization treatment and large in coercive force is obtained. The above molded body is subjected to a hydrogenation.recrystallization treatment, whereby an R-T-B anisotropic bonded magnet possessed of a demagnetization curve excellent in angularity can be manufactured because the molded body is kept high in degree of orientation as it is.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to various motors,
The present invention relates to a method for producing an anisotropic R (rare earth element) -T (iron group element) -B based bonded magnet that can be used for an actuator or the like. Roughness of the demagnetization curve and little change with time in magnetic characteristics are obtained by crushing the coarsely crushed powder, subjecting the coarsely crushed powder to hydrogenation / recrystallization treatment after molding, and further bonding treatment with a resin for bonding. The present invention relates to a method for manufacturing a T-B anisotropic bond magnet.

[0002]

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

The RTB-based alloy magnet produced by such a hydrogenation / recrystallization treatment method has a large coercive force and magnetic anisotropy. This treatment gives a structure having a very fine recrystallized grain size, substantially an average recrystallized grain size of 0.1 μm to 1 μm, and is magnetically tetragonal Nd ₂ Fe ₁₄
This is because the crystal grain size is close to the single domain critical grain size of the B-based compound, and these ultrafine crystals are recrystallized with the crystal orientations aligned to some extent. It is considered that this crystal orientation is the same as that of the raw material alloy powder even after the hydrogenation / recrystallization treatment.

[0004]

However, the R-T-B type bonded magnet made of the powder produced by the hydrogenation / recrystallization treatment method as a raw material has a hydrogen content depending on the structure of the alloy ingot used for the treatment and the pulverization method. There is a drawback that the magnetization of the powder produced by the crystallization / recrystallization treatment method is lowered.

Further, the magnetic characteristics of the bonded magnet produced from the powder produced by the above-mentioned hydrogenation / recrystallization treatment method are as follows:
The coercive force is large, so the magnetism is poor and the orientation during molding is 2
A large magnetic field of about 0k0e is required. Among them, the radial orientation, which occupies a large proportion in the bonded magnet, has a drawback that the magnetic characteristic level is not different from that of the isotropic one because such a large orientation magnetic field cannot be obtained during molding.

When the orientation of the bond magnet is insufficient, the squareness of the demagnetization curve of the bond magnet is poor, the irreversible thermal demagnetization rate becomes large, and the magnetic flux required when actually incorporated in a motor or the like is generated. There was a drawback that it could not be obtained and could not function as a motor. Therefore, the inventors have proposed a method for preventing a decrease in magnetization by performing so-called hydrogen pulverization before the hydrogenation / recrystallization treatment method (Japanese Patent Application No. 6-95791).
No.)

However, in the manufacturing method in which the hydrogen pulverization and the hydrogenation / recrystallization treatment method are combined, it is possible to prevent the decrease of the magnetization of the obtained powder, but it is difficult to magnetize the bond magnet manufactured from the powder as a raw material. Therefore, the drawback that the degree of orientation is lowered and thereby the magnetic property level is not improved cannot be improved.

Furthermore, the bonded magnet produced from the powder obtained by the hydrogenation / recrystallization treatment method disclosed in the above publication is:
There is a drawback that the magnetic characteristics change greatly with time, and the useful life of the magnet becomes extremely short depending on the use environment. This is because the powder is destroyed by kneading or pressing with the resin at the time of molding, so that the strong oxide layer on the surface of the powder generated when the powder is produced by the hydrogenation / recrystallization treatment method is destroyed. Conceivable.

As a countermeasure against this, Japanese Patent Laid-Open No. 6-342707
Japanese Patent Laid-Open Publication No. 2-212058 describes a powder obtained by a hydrogenation / recrystallization treatment method.
A method of improving heat resistance by heat treatment in a vacuum or an inert atmosphere at 00 ° C to 500 ° C is disclosed. However, this method also cannot avoid the fact that the powder in the molded body is destroyed because the powder is formed into a molded body after heat treatment, resulting in a large change in magnetic characteristics over time.

The present invention is a method for producing an R-T-B type anisotropic bonded magnet by a hydrogenation / recrystallization treatment method, which improves the temporal change of the magnetic characteristics and has a good squareness of the demagnetization curve. It is an object of the present invention to provide a manufacturing method for obtaining an R-T-B type anisotropic bonded magnet having a.

[0011]

The inventors of the present invention have made R-T-B
When hydrogenation and recrystallization treatment is performed as it is on the ingots of system alloy,
Since the temperature is raised in a hydrogen atmosphere, the shape of the alloy changes before and after the treatment due to the hydrogen absorption / disintegration method, so-called hydrogen crushing, during heating, but by using this as a molded body of alloy powder crushed by the hydrogen crushing method. It was found that the change in shape can be avoided.

Further, it has been found that the change over time in magnetic characteristics is further improved by forming the compacted body of the R-T-B type alloy powder and then subjecting it to the hydrogenation / recrystallization treatment. It was Furthermore, as a method of improving the degree of orientation, more specifically, the squareness of the demagnetization curve, a raw material powder having a very small coercive force before hydrogenation / recrystallization treatment of an R-T-B alloy powder is subjected to a magnetic field. When molded with, a compact with a much higher degree of orientation can be obtained compared to when a powder with a large coercive force after hydrogenation / recrystallization treatment is molded in a magnetic field, and this should be subjected to hydrogenation / recrystallization treatment. Since the good orientation degree added to the molded body before the treatment does not change after the treatment, it is possible to manufacture an R-T-B type anisotropic bonded magnet having a better squareness of the demagnetization curve than before. That is, the present invention has been completed.

That is, according to the present invention, an RTB-based alloy ingot is subjected to a hydrogen absorption / disintegration method so as to have an average particle size of 50 μm to 500 μm.
After roughly crushing to μm, shaping the coarsely crushed powder into a predetermined shape, subjecting to hydrogenation / recrystallization treatment, and then cooling, the molded body obtained is impregnated with the binding resin or immersed in the resin, This is a method for producing an R-T-B type anisotropic bonded magnet that is subjected to a bonding treatment. In addition, in the above manufacturing method, a method for manufacturing an R-T-B type anisotropic bonded magnet in which molding is performed in a magnetic field is also proposed.

Further, the present invention is the above manufacturing method, wherein the R-T-B type alloy ingot has an R content of 10 to 20 at%.
(R: at least one of rare earth elements including Y, and P
1 or 2 kinds of r or Nd is contained in 50% or more of R), T: 67 to 85 at% (T: Fe or a part of Fe is replaced by 50% or less of Co), B: 4 to 10 at% ,
Alternatively, M: 10 at% or less (M: Al, Ti,
V, Cr, Ni, Ga, Zr, Nb, Mo, In, S
A method for producing an R-T-B anisotropic bonded magnet composed of one or more of n, Hf, Ta and W) is also proposed.

The production method according to the present invention will be described in detail. An alloy ingot having the above composition is stored in hydrogen gas at 10 k to 1000 kPa at 600 ° C. or lower for 15 minutes to 100 hours by a hydrogen storage / disintegration method to obtain an average particle size of 50 μm. Coarsely pulverized to 500 μm and formed into a compact at a compacting pressure of 1 to 10 t / cm ² , and the compact is heated in a temperature range of 600 ° C. to 750 ° C. in H ₂ gas of 10 k to 1000 kPa at a heating rate of 10 ° C. / M
Temperature is raised at in to 200 ° C / min, and further at 750 ° C to 9
After heating and holding at 00 ° C. for 15 minutes to 8 hours to make the structure a mixed structure of at least four phases of R hydride, TB compound, T phase, and R ₂ T ₁₄ B compound, Ar gas or H
In a depressurized air flow with an absolute pressure of 10 Pa to 50 kPa by e gas, a recrystallization treatment of holding at 700 ° C to 900 ° C for 5 minutes to 8 hours is performed, and then cooling is performed to obtain a molded body,
By impregnating with a binding resin or immersing it in a bonding resin to perform a bonding treatment, R- which has a good change in magnetic characteristics over time
A TB type anisotropic bonded magnet can be obtained.

Further, the present invention is characterized in that the above-mentioned molding is carried out by 0.1 to 10.
By carrying out in a magnetic field of 1.0 MA / m, it is possible to obtain an R-T-B type anisotropic bonded magnet having good magnetic properties over time and a good degree of orientation.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION R, that is, a rare earth element used in a raw material alloy used in the present invention is Y, La, Ce, Pr,
Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, L
u is included, and at least two or more of these are Pr,
At least 1 or 2 of Nd is 50a of R
It is necessary to contain t% or more. 50 at% or more of R is P
The reason for using one or more of r and Nd is that sufficient magnetization cannot be obtained at less than 50 at%.

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

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

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

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

The hydrogen storage / disintegration method means R ₂ Fe ₁₄ in the alloy.
Phenomenon that spontaneously collapses with volume expansion when R ₂ Fe ₁₄ BH _x phase, RH _{2 3} phase, etc. are generated by storing or combining hydrogen in B phase or R-Co phase which is a grain boundary phase Is used. Therefore, hydrogenation in this invention
It is a completely different process from the recrystallization treatment.

The crushing method of the present invention is limited to the natural disintegration method by hydrogen storage because the R-T-B type alloy ingot and the alloy powder are heated in hydrogen when hydrogenated and recrystallized. For this reason, spontaneous collapse may proceed at the same time during the temperature rise, and the molded product after the hydrogenation / recrystallization treatment may collapse. Therefore, hydrogenation of the molded body as proposed in this invention
If it is attempted to continue after the recrystallization treatment, it is necessary that the volume expansion hardly occurs during the treatment, that is, the volume of the alloy is expanded in advance by hydrogen absorption. Therefore, the method of crushing the alloy ingot is the natural disintegration method by absorbing hydrogen.

The pressure of hydrogen used in the hydrogen storage natural disintegration method is set to 10 k to 1000 kPa. When the pressure is less than 10 kPa, the disintegration does not proceed sufficiently. Aspect and safety are not preferable. Therefore, the pressure range is 10k-10
00 kPa.

In the present invention, the temperature at which hydrogen is occluded is set to 600 ° C. or lower because R ₂ Fe exceeds 600 ° C.
_{14 The} reaction in which the B phase is decomposed into RH _{2 3} , α-Fe, Fe ₂ B, etc. proceeds, and spontaneous disintegration does not occur sufficiently, so that the meaning of the pulverizing step is lost. Therefore, the temperature is set to 600 ° C. or less. However, if the temperature is lower than 0 ° C, the reaction for spontaneously disintegrating, that is, the reaction to the R ₂ Fe ₁₄ BH _x phase, the RH _{2 3} phase, etc. is difficult to proceed, so the temperature is set to 0 ° C or higher.

With respect to the time of holding in hydrogen gas, there is a reaction latency of several minutes to 15 minutes for spontaneous decay due to hydrogen occlusion, so 15 minutes is required for sufficient reaction (natural decay). The above is necessary. Further, even if the natural disintegration step by hydrogen storage is carried out for 100 hours or more, there is no substantial effect and the cost becomes high. Therefore, the holding time is 15 minutes to 100 hours.

The average particle size of the coarsely crushed powder of the present invention is 50 μm.
The reason for limiting the particle size to ˜500 μm is that if the average particle size is less than 50 μm, the magnetic properties may be deteriorated due to the oxidation of the powder, the density of the molded body may be difficult to improve, and the magnetization after forming the bond magnet may be reduced. On the other hand, if the average particle size exceeds 500 μm, the particle size becomes too large and handling during molding becomes difficult. Therefore, the average particle size of the coarsely pulverized powder is 50 μm to 500 μm.
And More preferable average particle size is 70 μm to 300 μm.
m.

The molding in the present invention may be ordinary compression molding, and the molding pressure is preferably 1 to 10 ton / cm ² . If it is less than 1 ton / cm ² , the strength of the molded product is low and it is difficult to handle, and the density of the molded product is low.
The magnetization becomes low after the recrystallization treatment. Further, the higher the molding pressure is, the higher the density of the molded body is.
When it exceeds on / cm ² , the density is hardly improved and the equipment becomes large in scale, which causes an increase in manufacturing cost and is not preferable. Therefore, the molding pressure is set to 1 to 10 ton / cm ² .

Although the magnetic properties of the bonded magnet are remarkably improved by performing the molding in the magnetic field, the magnetic field strength when the molding is performed in the magnetic field is preferably 0.1 to 1.0 MA / m. If it is less than 0.1 MA / m, the orientation is insufficient and there is no point in molding in a magnetic field, and if it exceeds 1.0 MA / m, the degree of orientation of the molded product is saturated, and the equipment becomes large, resulting in a manufacturing cost increase. It causes an increase and is not preferable. Therefore,
0.1 to 1.0 MA / m.

The hydrogenation / recrystallization treatment of the present invention refers to a tetragonal Nd ₂ Fe ₁₄ B type compound at a high temperature, actually 60.
When reacted with H ₂ gas in the temperature range of 0 to 900 ° C., R
Phase separation into H _{2 ■ 3} , α-Fe, Fe ₂ B, etc., and removal of H ₂ gas by recrystallization treatment at the same temperature range gave a recrystallized structure of tetragonal Nd ₂ Fe ₁₄ B type compound again. Is to be done.

However, in reality, the crystal grain size of the decomposition product and the degree of reaction differ depending on the hydrotreating conditions, and the metallographic structure in the hydrogenated state is clearly different at hydrogenation temperatures of less than 750 ° C. and above 750 ° C. . This difference in metal structure is due to the magnetic properties of the magnet powder after recrystallization treatment,
In particular, it greatly affects the magnetic anisotropy.

Further, the recrystallization condition has a great influence on the recrystallized state of the tetragonal Nd ₂ Fe ₁₄ B type compound, and the magnetic properties, especially the coercive force, of the magnet powder produced by the hydrogenation / recrystallization treatment method. Greatly affect the. Furthermore, in the step of heating the tetragonal Nd ₂ Fe ₁₄ B type compound in the H ₂ gas in the hydrogenation / recrystallization treatment, phase separation into RH _{2 ■ 3} , α-Fe, Fe ₂ B, etc. is carried out by the rare earth element. In the reaction, there is a region where the reaction does not proceed depending on the hydrogen partial pressure, and for R, the hydrogen pressure greatly affects the magnetic properties, particularly the squareness and the coercive force, depending on the element.

[0033] In this invention, when heating with H ₂ gas, reasons for 10k~1000kPa H ₂ gas pressure is not above the decomposition reaction proceed sufficiently at lower than 10 kPa, also exceeds 1000kPa process Since the equipment becomes too large, which is not preferable in terms of industrial cost and safety, the pressure range was set to 10 k to 1000 kPa. More preferable pressure range is 100 k to 350 kPa
It is.

The heat treatment temperature in H ₂ gas is 750 to 750.
900 ° C is desirable. If it is less than 600 ° C, RH _{2 ■ 3} , α-
The decomposition reaction into Fe, Fe ₂ B, etc. does not occur, and 6
In the temperature range of 00 ° C. to 750 ° C., the decomposition reaction proceeds almost completely, an appropriate amount of R ₂ Fe ₁₄ B phase does not remain in the decomposition product, and it is magnetic and crystallographically oriented after the recrystallization treatment. Since sufficient anisotropy cannot be obtained, heating at 750 ° C. or higher is necessary. Further, when the temperature exceeds 900 ° C., RH _{2 3} becomes unstable, and the product grains grow to form tetragonal Nd ₂ Fe.
₁₄ It becomes difficult to obtain an ultrafine crystal structure of B-type compound.

When the hydrogenation temperature range is 750 ° C. to 900 ° C., R ₂ F which becomes the nucleus of the recrystallization reaction during dehydrogenation.
e _{14 Since the} B phase is dispersed and remains in an appropriate amount, R ₂ after recrystallization is
The crystal orientation of the T ₁₄ B phase is determined by the residual R ₂ Fe ₁₄ B phase, and as a result, the crystal orientation of the recrystallized structure coincides with the crystal orientation of the raw material ingot and exhibits a large anisotropy. Therefore, the temperature range of the hydrogenation treatment is set to 750 ° C to 900 ° C.

Regarding the heat treatment holding time, 15 minutes or more is required to sufficiently carry out the above decomposition reaction, and if it exceeds 8 hours, the residual R ₂ Fe ₁₄ B phase decreases and recrystallization occurs. It is not preferable because the magnetic anisotropy after the treatment is lowered. Therefore, the heating and holding is performed for 15 minutes to 8 hours.

The temperature rising rate in H ₂ gas is 10 to 200.
C / min is desirable. When it is less than 10 ° C / min,
In the temperature rising process, the decomposition reaction proceeds through the temperature range of 600 to 750 ° C., so that the decomposition is completed and the mother phase, that is, the R ₂ Fe ₁₄ B phase does not remain, and the magnetic field after dehydrogenation treatment Most of the crystalline and crystallographic anisotropy is lost. If the temperature rising rate is 10 ° C / min or more, 600 to 750 ° C
Reaction did not proceed sufficiently in the region of 7 and the mother phase remained
Since the hydrogenation temperature range of 50 to 900 ° C. is reached, it is possible to obtain a powder having a large magnetic and crystal orientation anisotropy after the recrystallization treatment. Therefore, the heating rate is 750
It is necessary to be 10 ° C./min or more in a temperature range of not more than 10 ° C. In addition, a temperature rising rate of more than 200 ° C./min is practically difficult to achieve even if an infrared furnace or the like is used, and even if it is possible, equipment costs increase, which is not preferable. Therefore, the rate of temperature rise is set to 10 to 200 ° C./min.

The recrystallization treatment of the present invention is carried out under a reduced pressure in an atmosphere of an inert gas, specifically Ar gas or He gas, whereby the substantial H ₂ partial pressure around the raw material is almost equal to the equilibrium hydrogen pressure. , For example, it becomes about 1 kPa at 850 ° C,
The recrystallization reaction proceeds gradually. The reason why the inert gas is limited to Ar or He is that Ar is easy to use in terms of cost, and H is preferable in terms of H ₂ gas replacement and temperature controllability.
This is because e gas is excellent. Other rare gases have no merit in performance and have a problem in cost. N ₂ gas, which is generally treated as an inert gas,
It is not suitable because it reacts with rare earth compounds to form nitrides.

If the absolute pressure of the atmosphere is less than 10 Pa, the recrystallization reaction rapidly occurs and the temperature drop due to the chemical reaction is large. Furthermore, since the recrystallization reaction is too rapid, coarse crystal grains are mixed in the structure of the magnet powder after cooling, and the coercive force is greatly reduced. On the other hand, when the absolute pressure of the atmosphere exceeds 50 kPa, the recrystallization reaction takes too long, which poses a practical problem such as manufacturing cost. Therefore, the absolute pressure of the atmosphere is set to 10 Pa to 50 kPa.

The reason why the recrystallization process is carried out in a reduced pressure air flow is to prevent the furnace pressure from rising due to the H ₂ gas released from the raw material by the recrystallization reaction.
Practically, the inert gas is introduced from one side, the other side is evacuated by the vacuum pump, and the pressure is controlled by using the flow rate adjusting valve attached to each of the supply port and the exhaust port.

In the present invention, the recrystallization temperature is 7
If the temperature is less than 00 ° C, H ₂ is not separated from the RH _{2 3} phase, or the recrystallization of the tetragonal Nd ₂ Fe ₁₄ B type compound does not proceed sufficiently, and if it exceeds 900 ° C, the tetragonal N 2
Although the d ₂ Fe ₁₄ B-type compound is produced, the recrystallized grains grow coarsely and a high coercive force cannot be obtained. Therefore, the temperature range of the recrystallization treatment is 700 ° C. to 900 ° C.

The heat treatment holding time depends on the exhaust capacity of the treatment equipment, but it is necessary to hold it for at least 5 minutes or more in order to sufficiently carry out the recrystallization reaction. However, on the other hand, if the crystals are coarsened by the secondary recrystallization reaction, the coercive force is lowered. Therefore, it is preferable that the time is as short as possible. Therefore, heating and holding for 5 minutes to 8 hours is sufficient.

The recrystallization treatment is preferably carried out after the hydrogenation treatment from the viewpoint of preventing the oxidation of the raw material and the thermal efficiency of the treatment equipment. After the hydrogenation treatment, the raw material is once cooled. The heat treatment for recrystallization may be performed again.

The bonding treatment in the present invention indicates that the resin for bonding is infiltrated or cured after the resin is immersed in the resin. Resin impregnation is vacuum infiltration in a vacuum atmosphere,
Alternatively, it may be selected depending on the shape purpose of the molded product, the type of resin, etc., such as the method of immersing the molded product in the resin.

The bonding resin used for the bonding treatment is preferably an epoxy resin, a phenol resin, an acrylic resin or the like which can be immersed and impregnated. Further, in order to improve magnetic properties and improve moldability, a molding aid such as polyvinyl alcohol, polypinyl butyral, carboxymethyl cellulose, polyethylene glycol, paraffin, linoleic acid and oleic acid may be used at the time of molding.

Curing of the resin means performing heat treatment for about one hour at the curing temperature of the resin used. This may be selected according to the curing conditions of the resin used. The atmosphere for curing is vacuum or Ar to prevent oxidation during curing.
It is desirable to use an inert atmosphere such as nitrogen.

[0047]

【Example】

Example 1 An ingot having a composition shown in Table 1 obtained by melting by a high frequency induction melting method was annealed at 1100 ° C. for 24 hours in an Ar atmosphere. This ingot was put in a pressure vessel and evacuated to 1 Pa or less. After that, hydrogen gas having a purity of 99.999% or more was introduced to adjust the pressure in the container to 200 kPa and 10
Hold at 100 ° C. for hours. Further, after sizing to an average particle size of 100 μm in an Ar gas atmosphere (O ₂ concentration of 0.1% or less), this coarsely pulverized powder was measured at 7 ton / cm ^{2 in a} 10 mm square.
According to the alignment conditions in Table 2, the alignment magnetic field was not applied or the molding was performed in the perpendicular magnetization of 1.2 MA / m under the pressure of 1.

The obtained molded body was put in a tubular furnace and evacuated to 1 Pa or less. Then, while introducing H ₂ gas having a purity of 99.999% or more, the hydrotreatment was performed under the hydrotreatment conditions shown in Table 2. The hydrogenated raw material thus obtained was subsequently recrystallized according to the recrystallization conditions shown in Table 2. A rotary pump was used for exhaust. After cooling, the sample was taken out when the raw material temperature became 50 ° C. or lower. Table 2 shows the survival results of the molded body at this time. Epoxy resin is vacuum dipped into the treated molded body,
It was cured at 1 ° C. for 1 hour in an Ar atmosphere (O ₂ concentration of 0.1% or less). Table 2 shows the magnetic characteristics of the bond magnet at this time.
No. in Table 2 FIG. 1 shows the changes over time in the magnetic properties of the 14 samples in the atmosphere at 100 ° C.

Comparative Example 1 An ingot having the composition shown in Table 1 obtained by melting by a high frequency induction melting method was annealed at 1100 ° C. for 24 hours in an Ar atmosphere. This ingot was placed in an Ar gas atmosphere (O ₂ concentration of 0.1%
In the following), a stamp mill was used to roughly pulverize to an average particle size of 100 μm, and the coarsely pulverized powder was then cut into a square of 10 mm and 7 ton / c.
According to the orientation conditions in Table 3 at a pressure of m ² , the orientation magnetic field was not applied, or molding was performed in the perpendicular magnetization of 1.2 MA / m.

The obtained molded body was put in a tubular furnace and evacuated to a pressure below IPa. Then, while introducing H ₂ gas having a purity of 99.999% or more, the hydrogenation treatment was performed under the hydrogenation treatment conditions shown in Table 3. The hydrogenated raw material thus obtained was subsequently subjected to recrystallization treatment under the recrystallization treatment conditions shown in Table 3. A rotary pump was used for exhaust. After cooling, the sample was taken out when the raw material temperature became 50 ° C. or lower. Table 3 shows whether or not the molded body can survive at this time.

Comparative Example 2 An ingot having the composition shown in Table 1 obtained by melting by a high frequency induction melting method was annealed at 1100 ° C. for 24 hours in an Ar atmosphere. This ingot was put in a pressure vessel and evacuated to 1 Pa or less. After that, hydrogen gas having a purity of 99.999% or more is introduced, and the pressure in the container is set to 200 kPa.
Hold at 00 ° C. Furthermore, after sizing to an average particle size of 100 μm in an Ar gas atmosphere (O ₂ concentration of 0.1% or less),
It was put in a tubular furnace and evacuated to 1 Pa or less. Then, while introducing H ₂ gas having a purity of 99.9999% or more, hydrogenation treatment was performed under the hydrogenation treatment conditions shown in Table 4.
The hydrogenated raw material thus obtained was subsequently subjected to recrystallization treatment under the recrystallization treatment conditions shown in Table 4.

A rotary pump was used for evacuation. After cooling, the sample was taken out when the raw material temperature became 50 ° C. or lower. The obtained powder is 7 ton / c in 10 mm square.
According to the alignment condition of Table 4 at a pressure of m ² , the alignment magnetic field was not applied, or the molding was performed in the perpendicular magnetization of 1.2 MA / m. After molding, soak the epoxy resin in a vacuum house, 150 ℃,
It was cured in an Ar atmosphere (O ₂ concentration of 0.1% or less) for 1 hour. Table 4 shows the magnetic characteristics of the bonded magnet at this time. Moreover, No. FIG. 1 shows the changes over time in the magnetic properties of the 14 samples in the atmosphere at 100 ° C. FIG. 1 shows the rate of decrease in (BH) max that changes with the passage of time. The case of the present invention formed before hydrogenation / recrystallization treatment is shown by a solid line with a circle, and after hydrogenation / recrystallization treatment is shown. The case of the molded comparative example is indicated by a dot-dash line.

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

INDUSTRIAL APPLICABILITY The present invention is a method for producing an RTB-based bonded magnet by a hydrogenation / recrystallization treatment method. Recrystallization treatment, the molded body is allowed to survive after the treatment, and is characterized by forming a bond by impregnating or immersing a bonding resin, and the molded body can be maintained even after hydrogenation / recrystallization treatment, It is possible to obtain an R-T-B type anisotropic bonded magnet having little change in magnetic properties over time, excellent orientation, and good squareness of demagnetization curve.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a lapse of time and a decrease rate of (BH) max.

Claims (4)

[Claims] 1. An RTB-based alloy ingot is roughly crushed by a hydrogen storage / disintegration method to an average particle size of 50 μm to 500 μm, and the coarsely crushed powder is molded into a predetermined shape, and then subjected to hydrogenation / recrystallization treatment. Then, the molded product obtained by cooling is impregnated with the resin for binding or immersed in the resin, and the resulting resin is subjected to a bonding treatment R-
A manufacturing method of a TB type anisotropic bond magnet. 2. The method for manufacturing an R-T-B anisotropic bonded magnet according to claim 1, wherein the molding is performed in a magnetic field. 3. The method according to claim 1 or 2, wherein R-
The T-B alloy ingot is R: 10 to 20 at% (at least one of rare earth elements including R: Y, and Pr or N).
1 or 2 of d is contained in 50% or more of R), T:
67 to 85 at% (T: Fe or a part of Fe is 50%
(Substituted with Co below), B: 4-10 at% R-
A manufacturing method of a TB type anisotropic bond magnet. 4. The R- according to claim 1 or claim 2.
The T-B alloy ingot is R: 10 to 20 at% (at least one of rare earth elements including R: Y, and Pr or N).
1 or 2 of d is contained in 50% or more of R), T:
67 to 85 at% (T: Fe or a part of Fe is 50%
Substituted with Co below), B: 4 to 10 at%, M: 10 a
t% or less (M: Al, Ti, V, Cr, Ni, Ga, Z
1 of r, Nb, Wo, In, Sn, Hf, Ta, V
Or a mixture of two or more types) of the RTB-based anisotropic bonded magnet.