JP3623571B2 - Method for producing RTB-based anisotropic bonded magnet - Google Patents

Description

【００５４】
【表２】

【００５５】
【表３】

【００５６】
【表４】

【００５７】
【発明の効果】
この発明は、Ｒ−Ｔ−Ｂ系ボンド磁石を水素化・再結晶処理法により製造する方法において、水素粉砕で得られた粉末を成形もしくは磁界中で成形後に、得られた成形体に水素化・再結晶処理し、該処理後も成形体を存続させ、該成形体に結合用樹脂を含浸もしくは浸漬させることでボンド化することを特徴とし、水素化・再結晶処理後も成形体を存続させることができ、磁気特性の経時変化が少なく、配向性にすぐれ、良好な滅磁曲線の角型性を有するＲ−Ｔ−Ｂ系異方性ボンド磁石を得ることができる。
【図面の簡単な説明】
【図１】時間経過と（ＢＨ）ｍａｘの低下率との関係を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
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 various motors, actuators, etc., and an R-T-B alloy ingot. After the coarsely pulverized powder is formed into a coarsely pulverized powder by the hydrogen storage / disintegration methodThe obtained molded bodyR-T-B system anisotropic bonded magnet with less demagnetization curve squareness and magnetic property change with time by hydrogenating / recrystallizing and bonding with resin for bonding The present invention relates to a manufacturing method for obtaining
[0002]
[Prior art]
The manufacturing method of RT- (M) -B-based anisotropic bonded magnet powder is disclosed, for example, in JP-A-1-132106 as a manufacturing method by hydrogenation / recrystallization treatment.
That is, the hydrogenation / recrystallization treatment method is an R-T- (M) -B-based material alloy ingot or powder,₂Gas atmosphere or H₂In a mixed atmosphere of gas and inert gas, the temperature is maintained at 500 ° C. to 1000 ° C.₂After occlusion of H₂Gas pressure 13Pa (1 × 10^-1Torr) The following vacuum atmosphere or H₂Gas partial pressure 13 Pa (1 × 10^-1Torr) Degassing at a temperature of 500 ° C. to 1000 ° C. until the following inert gas atmosphere is reached₂This process discloses a process of cooling and then cooling, and this publication discloses that powder obtained by hydrogenation / recrystallization treatment is pulverized and compounded with a resin to form an RTB bond magnet. Yes.
[0003]
The RTB-based alloy magnet manufactured by such a hydrogenation / recrystallization treatment method has a large coercive force and magnetic anisotropy. This results in a structure having a very fine recrystallized grain size, substantially an average recrystallized grain size of 0.1 μm to 1 μm by the above treatment, and is magnetically tetragonal Nd.₂Fe₁₄This 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 a certain degree of crystal orientation. 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]
[Problems to be solved by the invention]
However, an R-T-B type bonded magnet made from powder produced by the hydrogenation / recrystallization treatment method is produced by the hydrogenation / recrystallization treatment method depending on the structure of the alloy ingot used for the treatment and the grinding method. There was a drawback that the magnetization of the powder would decrease.
[0005]
In addition, the magnetic properties of the bonded magnet manufactured using the powder manufactured by the hydrogenation / recrystallization process as a raw material are poorly magnetized due to the large coercive force, and a large magnetic field of about 20 k0e is required for the orientation during molding. Become. Among them, radial orientation, which accounts for a large proportion of bonded magnets, has a disadvantage that the magnetic property level is not different from that of isotropic because such a large orientation magnetic field cannot be obtained during molding.
[0006]
If the orientation of the bond magnet is insufficient in this way, the squareness of the demagnetization curve of the bond magnet will be poor, the irreversible thermal demagnetization rate will increase, and the required magnetic flux will not be obtained when it is actually incorporated in a motor or the like. However, it did 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).
[0007]
However, in the manufacturing method combining this hydrogen pulverization and the hydrogenation / recrystallization treatment method, it is difficult to magnetize the bonded magnet manufactured using the powder as a raw material, even though the decrease in magnetization of the obtained powder can be prevented. The disadvantage that the degree of orientation was lowered and the magnetic property level was not improved thereby could not be improved.
[0008]
Furthermore, the bond magnet manufactured from the powder obtained by the hydrogenation / recrystallization treatment method disclosed in the above publication has a large change over time in the magnetic properties, and depending on the usage environment, the useful life as a magnet is significantly shortened. There was a drawback. This is because the powder is destroyed by kneading and pressing with the resin at the time of molding, so that a strong oxide layer on the powder surface produced when produced by the hydrogenation / recrystallization treatment method is destroyed. Conceivable.
[0009]
As a countermeasure, JP-A-6-342707 discloses a method for improving heat resistance by heat-treating a powder obtained by a hydrogenation / recrystallization treatment method in a vacuum of 200 ° C. to 500 ° C. or in an inert atmosphere. Is disclosed. However, this method cannot prevent the powder in the molded body from being destroyed because the powder is formed into a molded body after heat treatment, and the change in magnetic properties with time is increased.
[0010]
The present invention provides an R-T-B type anisotropic bonded magnet manufactured by a hydrogenation / recrystallization treatment method, which improves the change over time in magnetic characteristics and has a good demagnetization curve squareness. The object is to provide a production method for obtaining a -T-B type anisotropic bonded magnet.
[0011]
[Means for Solving the Problems]
When the inventors perform hydrogenation / recrystallization treatment on an R-T-B alloy ingot as it is, the temperature rises in a hydrogen atmosphere. Although the alloy shape changed before and after, it was found that the change in shape can be avoided by forming a compact of the alloy powder pulverized by the hydrogen pulverization method.
[0012]
In addition, after forming the RTB-based alloy powder into a compact,In the obtained molded bodyIt has been found that by performing the hydrogenation / recrystallization treatment, the temporal change of the magnetic properties is further improved as compared with the prior art.
Furthermore, as a method for improving the degree of orientation, more specifically, the squareness of the demagnetization curve, the raw powder having a very small coercive force before hydrogenation / recrystallization treatment is applied to the RTB-based alloy powder in the magnetic field. When molded with, a compact with a much higher degree of orientation is obtained than when a powder with a large coercive force after hydrogenation / recrystallization treatment is molded in a magnetic field, and this is subjected to hydrogenation / recrystallization treatment. Since the good degree of orientation 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 demagnetization curve squareness than before. As a result, the present invention was completed.
[0013]
That is, the present invention is obtained by roughly pulverizing an RTB-based alloy ingot to an average particle size of 50 μm to 500 μm by a hydrogen storage and collapse method, and forming the coarsely pulverized powder into a predetermined shape.In the obtained molded bodyA method for producing an R-T-B type anisotropic bonded magnet in which a molded product obtained by performing hydrogenation / recrystallization treatment and then cooling is impregnated with or immersed in a bonding resin, and this is bonded. It is.
In addition, in the above manufacturing method, a manufacturing method of an RTB-based anisotropic bonded magnet in which molding is performed in a magnetic field is also proposed.
[0014]
Further, according to the present invention, in the above manufacturing method, the RTB-based alloy ingot is R: 10 to 20 at% (R: a rare earth element including Y, and one kind of Pr or Nd) Or 2 types are contained in 50% or more of R), T: 67 to 85 at% (T: Fe or a part of Fe is substituted with 50% or less Co), B: 4 to 10 at%, or M: 10 at % Of R-T-B system consisting of 1% or more (M: Al, Ti, V, Cr, Ni, Ga, Zr, Nb, Mo, In, Sn, Hf, Ta, W) We also propose a method for manufacturing anisotropic bonded magnets.
[0015]
The production method according to the present invention will be described in detail. The alloy ingot having the above composition is roughly coarsened to an average particle size of 50 μm to 500 μm by a hydrogen occlusion / disintegration method in which the ingot is held in hydrogen gas of 10 k to 1000 kPa at 600 ° C. or less for 15 minutes to 100 hours. Crushed, molding pressure 1-10t / cm²The molded body is made into a molded body at a pressure of 10 k to 1000 kPa.₂In gas, a temperature range of 600 ° C. to 750 ° C. is heated at a rate of temperature increase of 10 ° C./min to 200 ° C./min, and further heated and held at 750 ° C. to 900 ° C. for 15 minutes to 8 hours. Compound, TB compound, T phase, R₂T₁₄After making a mixed structure of at least four phases of the B compound, recrystallization is further performed at 700 ° C. to 900 ° C. for 5 minutes to 8 hours in a reduced pressure air flow with Ar gas or He gas at an absolute pressure of 10 Pa to 50 kPa. Obtained by processing and then coolingSaidAn R-T-B type anisotropic bonded magnet having a good change in magnetic properties with time can be obtained by impregnating the molded article with a bonding resin or by immersing it in the bonding resin to bond it.
[0016]
In addition, the present invention performs the above molding in a magnetic field of 0.1 to 1.0 MA / m, so that an R—T—B system anisotropic bond having a good change in magnetic properties with time and a good degree of orientation. A magnet can be obtained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
R, that is, a rare earth element used in the raw material alloy used in the present invention includes Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu, and at least two of these are included. Therefore, it is necessary to contain at least one or two of Pr and Nd in an amount of 50 at% or more of R. The reason why 50 at% or more of R is one or more of Pr and Nd is that sufficient magnetization cannot be obtained if it is less than 50 at%.
[0018]
When R is less than 10 at%, the coercive force decreases due to precipitation of the α-Fe phase, and when it exceeds 20 at%, the desired tetragonal Nd₂Fe₁₄In addition to the B-type compound, many R-rich second phases are precipitated, and if this second phase is too much, the magnetization of the alloy decreases. Accordingly, the range of R is 10 to 20 at%.
[0019]
T is an iron group element and includes Fe and Co. When T is less than 67 at%, a low coercive force and low magnetization second phase precipitates and the magnetic properties are deteriorated, and when it exceeds 85 at%, coercivity and squareness are reduced due to precipitation of α-Fe phase. 67 to 85 at%.
Further, the necessary magnetic properties can be obtained with Fe alone, but the addition of Co is useful for improving the Curie temperature, that is, improving the heat resistance, and can be added as necessary. If the atomic ratio of Fe to Co is 50% or less, Nd₂Fe₁₄Since the amount of decrease in the saturation magnetization itself of the B-type compound becomes large, the atomic ratio of Fe is set to 50% or more.
[0020]
B is tetragonal Nd₂Fe₁₄It is essential for stably depositing the B-type crystal structure. Addition amount is R at 4at% or less₂T₁₇A phase precipitates to reduce the coercive force, and the squareness of the demagnetization curve is significantly impaired. Moreover, when added exceeding 10 at%, the 2nd phase with small magnetization precipitates and the magnetization of powder is reduced. Therefore, B is 4 to 10 at%.
[0021]
In addition, as other additive elements, in order to make anisotropy for the purpose of improving magnetic properties even after hydrogenation / recrystallization treatment, the decomposition reaction of the parent phase is not completely terminated during hydrogenation. I.e. R₂T₁₄An element effective for stabilizing the B phase and intentionally remaining is desired. Examples of particularly remarkable effects include Al, Ti, V, Cr, Ni, Ga, Zr, Nb, Mo, In, Sn, Hf, Ta, and W.
The additive element does not have to be added at all. However, if it exceeds 10 at%, a non-ferromagnetic second phase precipitates and lowers the magnetization, so the addition amount is set to 10 at% or less.
[0022]
The hydrogen storage decay method is the R in the alloy₂Fe₁₄By storing or combining hydrogen into the B phase or the R-Co phase which is the grain boundary phase, R₂Fe₁₄BH_xPhase and RH_{2 ■ 3}It utilizes the phenomenon of spontaneous decay with volume expansion when generating phases and the like. Therefore, it is a completely different process from the hydrogenation / recrystallization process in the present invention.
[0023]
The pulverization method of the present invention is limited to the natural decay method by hydrogen storage because the R-T-B type alloy ingot and alloy powder are heated in hydrogen when hydrogenated and recrystallized. There is a possibility that spontaneous collapse will proceed simultaneously during warming, and the molded body after hydrogenation / recrystallization treatment may collapse. For this reason, if a molded body as proposed in the present invention is allowed to survive after the hydrogenation / recrystallization treatment, there is almost no volume expansion during the treatment, that is, the volume of the alloy is expanded by hydrogen storage in advance. It is necessary to do. Therefore, the method of crushing the alloy ingot is a natural decay method using hydrogen storage.
[0024]
The hydrogen pressure used in the hydrogen storage natural decay method was set to 10 k to 1000 kPa because the breakdown did not proceed sufficiently if it was less than 10 kPa, and if it exceeded 1000 kPa, the treatment facility became too large, and it was industrially costly and safe. It is not preferable in terms of the aspect. Therefore, the pressure range was 10 k to 1000 kPa.
[0025]
In the present invention, the temperature at which hydrogen is occluded is set to 600 ° C. or lower.₂Fe₁₄B phase is RH_{2 ■ 3}, Α-Fe, Fe₂The reaction of decomposing into B or the like proceeds, the natural decay does not occur sufficiently, and the meaning as the pulverization process is lost. Therefore, it shall be 600 degrees C or less. However, at a temperature lower than 0 ° C., a reaction for spontaneous decay, that is, R₂Fe₁₄BH_xPhase and RH_{2 ■ 3}Since the reaction to the phase does not proceed easily, the temperature is set to 0 ° C. or higher.
[0026]
About the time to hold in hydrogen gas, since there is a reaction latency of several minutes to 15 minutes in the natural decay accompanying hydrogen occlusion, it takes 15 minutes or more to allow the reaction (natural decay) to take place sufficiently. is there. Moreover, even if such a natural decay process by occlusion of hydrogen is performed for 100 hours or more, there is no substantial effect and the cost is increased. Therefore, the retention time is 15 minutes to 100 hours.
[0027]
The reason why the average particle size of the coarsely pulverized powder of this invention is limited to 50 μm to 500 μm is that if the average particle size is less than 50 μm, the magnetic properties may be deteriorated due to oxidation of the powder, and the density of the molded body is difficult to improve. This is because the magnetization after it is lowered. On the other hand, when the average particle size exceeds 500 μm, the particle size is too large and handling during molding becomes difficult. Therefore, the average particle size of the coarsely pulverized powder is set to 50 μm to 500 μm. A more preferable average particle size is 70 μm to 300 μm.
[0028]
The molding in the present invention may be ordinary compression molding, and the molding pressure is 1 to 10 ton / cm.²Is desirable. 1 ton / cm²If it is less than 1, the strength of the molded body is low and difficult to handle, and the density of the molded body is low, so that the magnetization after the hydrogenation / recrystallization treatment is lowered. Further, the higher the molding pressure, the higher the density of the molded body, but 10 ton / cm.²Exceeding the density is not preferable because the density is hardly improved and the equipment becomes large, resulting in an increase in manufacturing cost. Therefore, the molding pressure is 1 to 10 ton / cm.²And
[0029]
Further, although the magnetic properties of the bonded magnet are remarkably improved by forming in a magnetic field, the magnetic field strength when forming in a 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 meaning in forming in a magnetic field, and if it exceeds 1.0 MA / m, the degree of orientation of the molded body is saturated and the equipment becomes large. This is undesirable because it increases. Therefore, it is set to 0.1-1.0 MA / m.
[0030]
The hydrogenation / recrystallization treatment of the present invention is tetragonal Nd.₂Fe₁₄Compared to the B-type compound, it is H at a high temperature, actually in the temperature range of 600-900 ° C.₂RH when reacted with gas_{2 ■ 3}, Α-Fe, Fe₂Phase separation into B, etc., and H in the same temperature range₂When the gas is removed by recrystallization, tetragonal Nd again₂Fe₁₄A recrystallized structure of the B-type compound is obtained.
[0031]
However, in reality, the crystal grain size of the decomposition product and the degree of reaction differ depending on the hydrotreating conditions, and the metal structure in the hydrogenated state is clearly different between a hydrogenation temperature of less than 750 ° C. and a temperature of 750 ° C. or more. This difference in metal structure greatly affects the magnetic properties of the magnet powder after the recrystallization treatment, particularly the magnetic anisotropy.
[0032]
Furthermore, depending on the recrystallization treatment conditions, tetragonal Nd₂Fe₁₄The recrystallization state of the B-type compound is greatly affected, and greatly affects the magnetic properties, particularly the coercive force, of the magnet powder produced by the hydrogenation / recrystallization treatment method. Furthermore, tetragonal Nd of hydrogenation and recrystallization treatment₂Fe₁₄B type compound to H₂In the process of heating in gas, RH is added by a rare earth element._{2 ■ 3}, Α-Fe, Fe₂There is a region where the phase separation reaction such as B does not proceed depending on the hydrogen partial pressure, and for R, the hydrogen pressure greatly affects the magnetic properties, particularly the squareness and coercive force, depending on the element.
[0033]
In this invention, H₂When heating in gas, H₂The reason why the gas pressure is set to 10 kPa to 1000 kPa is that the above-described decomposition reaction does not proceed sufficiently if the pressure is less than 10 kPa, and if it exceeds 1000 kPa, the treatment facility becomes too large, which is industrially preferable in terms of cost and safety. Therefore, the pressure range was set to 10 k to 1000 kPa. A more preferable pressure range is 100 k to 350 kPa.
[0034]
H₂As for the heat processing temperature in gas, 750-900 degreeC is desirable. RH below 600 ° C_{2 ■ 3}, Α-Fe, Fe₂The decomposition reaction into B does not occur, and the decomposition reaction proceeds almost completely in the temperature range of 600 ° C. to 750 ° C., and an appropriate amount of R is contained in the decomposition product.₂Fe₁₄Since the B phase does not remain and sufficient anisotropy is not obtained magnetically and crystallographically after the recrystallization treatment, heating at 750 ° C. or higher is necessary. Moreover, when it exceeds 900 degreeC, RH_{2 ■ 3}Becomes unstable and the product grows to form tetragonal Nd₂Fe₁₄It becomes difficult to obtain a B-type compound ultrafine crystal structure.
[0035]
If the temperature range of hydrogenation is in the range of 750 ° C. to 900 ° C., R, which is the nucleus of the recrystallization reaction during dehydrogenation₂Fe₁₄Since B phase is dispersed and remains in an appropriate amount, R after recrystallization₂T₁₄B phase crystal orientation remains R₂Fe₁₄As a result, the crystal orientation of the recrystallized structure coincides with the crystal orientation of the raw material ingot and shows a large anisotropy. Therefore, the temperature range of the hydrotreatment is set to 750 ° C to 900 ° C.
[0036]
Further, the heat treatment holding time is required to be 15 minutes or longer in order to sufficiently perform the above decomposition reaction.₂Fe₁₄This is not preferable because the B phase decreases and the magnetic anisotropy after the recrystallization treatment decreases. Accordingly, the heating and holding is performed for 15 minutes to 8 hours.
[0037]
H₂As for the temperature increase rate in gas, 10-200 degreeC / min is desirable. If it is less than 10 ° C./min, it passes through a temperature range of 600 to 750 ° C. during the temperature rising process while the decomposition reaction proceeds, so that it is completely decomposed and thus the parent phase, ie, R₂Fe₁₄The B phase does not remain, and the magnetic and crystal orientation anisotropy after the dehydrogenation process is almost lost. If the rate of temperature rise is 10 ° C./min or more, the reaction does not proceed sufficiently in the region of 600 to 750 ° C., and the hydrogenation temperature region of 750 to 900 ° C. is reached with the parent phase remaining. Later, a powder having a large anisotropy in magnetic and crystal orientation can be obtained. Therefore, the temperature rising rate needs to be 10 ° C./min or more in the temperature range of 750 ° C. or less. Further, a temperature increase rate exceeding 200 ° C./min is practically difficult even if an infrared furnace or the like is used, and even if possible, the equipment cost increases, which is not preferable. Therefore, the rate of temperature rise is set to 10 to 200 ° C./min.
[0038]
The recrystallization process of the present invention is performed under a reduced pressure of an inert gas, specifically, an Ar gas or He gas atmosphere.₂The partial pressure is approximately the equilibrium hydrogen pressure, for example, about 1 kPa at 850 ° C., and 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.₂This is because He gas is superior in terms of gas substitutability and temperature controllability. Other noble gases have no performance advantage and are costly. In general, N treated as an inert gas₂Gases are unsuitable because they react with rare earth compounds to form nitrides.
[0039]
When the absolute pressure of the atmosphere is less than 10 Pa, the recrystallization reaction occurs rapidly, 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, it takes too much time for the recrystallization reaction, which causes practical problems such as production costs. Therefore, the absolute pressure of the atmosphere was set to 10 Pa to 50 kPa.
[0040]
Also, what is performed in a reduced-pressure air flow during the recrystallization process is H released from the raw material by the recrystallization reaction.₂This is for preventing the furnace pressure from being increased by the gas. In practice, an inert gas is introduced from one side and exhausted by a vacuum pump from the other side, and the pressure is controlled using flow rate adjusting valves attached to the supply port and the exhaust port, respectively.
[0041]
In the present invention, when the recrystallization temperature is less than 700 ° C., RH_{2 ■ 3}H from the phase₂Does not occur or tetragonal Nd₂Fe₁₄Recrystallization of the B-type compound does not proceed sufficiently, and if it exceeds 900 ° C., tetragonal Nd₂Fe₁₄Although the B-type compound is produced, the recrystallized grains grow coarsely and a high coercive force cannot be obtained, so the temperature range of the recrystallization treatment is set to 700 ° C to 900 ° C.
[0042]
In addition, the heat treatment holding time depends on the exhaust capacity of the processing equipment, but it is necessary to hold the heat treatment for at least 5 minutes in order to sufficiently perform the recrystallization reaction. However, on the other hand, if the crystal is coarsened by a secondary recrystallization reaction, the coercive force is lowered, so that a shorter time is preferable. Therefore, heating and holding for 5 minutes to 8 hours is sufficient.
[0043]
The recrystallization treatment is preferably performed subsequent to the hydrogenation treatment from the viewpoint of preventing oxidation of the raw material and from the viewpoint of the thermal efficiency of the processing equipment, but after the hydrogenation treatment, the raw material is once cooled and then again. Heat treatment for recrystallization may be performed.
[0044]
The bonding treatment in the present invention indicates that the resin is cured after the immersion of the bonding resin or the immersion of the resin. The impregnation of the resin may be selected according to the shape of the molded body, the type of the resin, etc., such as vacuum soaking in a vacuum atmosphere or a method of immersing the molded body in the resin.
[0045]
The bonding resin used for the bonding process is preferably an epoxy resin, a phenol resin, an acrylic resin or the like that can be immersed and impregnated. In order to improve magnetic properties and improve moldability, polyvinyl alcohol and polyBiMolding aids such as nilbutyral, carboxymethylcellulose, polyethylene glycol, paraffin, linoleic acid, and oleic acid may be used.
[0046]
The resin is cured,Perform heat treatment for about 1 hour at the curing temperature of the resin used.U. This may be selected according to the curing conditions of the resin used. The atmosphere for curing is preferably a vacuum or an inert atmosphere such as Ar or nitrogen in order to prevent oxidation during curing.
[0047]
【Example】
Example 1
An ingot of the composition shown in Table 1 obtained by melting by high frequency induction melting was annealed in an Ar atmosphere at 1100 ° C. for 24 hours. This ingot was put in a pressure vessel and evacuated to 1 Pa or less. Thereafter, hydrogen gas having a purity of 99.999% or more was introduced, the pressure in the container was set to 200 kPa, and the temperature was maintained at 100 ° C. for 10 hours. Further, in an Ar gas atmosphere (O₂The particle size is adjusted to an average particle size of 100 μm at a concentration of 0.1% or less, and the coarsely pulverized powder is 10 mm square to 7 ton / cm.²According to the orientation conditions in Table 2, no orientation magnetic field was applied or molding was performed in a perpendicular magnetization of 1.2 MA / m.
[0048]
The obtained molded body was put in a tubular furnace and evacuated to 1 Pa or less. After that, H with a purity of 99.999% or more₂While introducing the gas, the hydrogenation treatment was performed under the hydrotreatment conditions shown in Table 2. The hydrogenation 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.
An epoxy resin is immersed in the processed molded body in a vacuum chamber, and the atmosphere is 150 ° C. for 1 hour in an Ar atmosphere (O₂The concentration was 0.1% or less. Table 2 shows the magnetic characteristics of the bonded magnet at this time. FIG. 1 shows the change over time in the magnetic properties of the 14 samples in the 100 ° C. atmosphere.
[0049]
Comparative Example 1
An ingot of the composition shown in Table 1 obtained by melting by high frequency induction melting was annealed in an Ar atmosphere at 1100 ° C. for 24 hours. This ingot is placed in an Ar gas atmosphere (O₂After roughly pulverizing to an average particle size of 100 μm using a stamp mill at a concentration of 0.1% or less, the coarsely pulverized powder was 10 to 10 square mm and 7 ton / cm.²According to the orientation conditions shown in Table 3 at a pressure of 5 ° C., an orientation magnetic field was not applied, or molding was performed in a perpendicular magnetization of 1.2 MA / m.
[0050]
The obtained molded body was put in a tubular furnace and evacuated to IPa or lower. After that, H with a purity of 99.999% or more₂While introducing the gas, the hydrogenation treatment was performed under the hydrotreatment conditions shown in Table 3. The hydrogenation raw material thus obtained was subsequently recrystallized according to the recrystallization 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 be continued at this time.
[0051]
Comparative Example 2
The ingot having the composition shown in Table 1 obtained by melting by the high frequency induction melting method was annealed in an Ar atmosphere at 1100 ° C. for 24 hours. This ingot was put in a pressure vessel and evacuated to 1 Pa or less. Thereafter, hydrogen gas having a purity of 99.999% or more was introduced, the pressure in the container was set to 200 kPa, and the temperature was maintained at 100 ° C. for 10 hours. Further, in an Ar gas atmosphere (O₂After adjusting the average particle size to 100 μm at a concentration of 0.1% or less, it was put into a tubular furnace and evacuated to 1 Pa or less. Thereafter, H with a purity of 99.9999% or more₂While introducing the gas, the hydrogenation treatment was performed under the hydrotreatment conditions shown in Table 4. The hydrogenation raw material thus obtained was subsequently recrystallized according to the recrystallization conditions shown in Table 4.
[0052]
A rotary pump was used for exhaust. After cooling, the sample was taken out when the raw material temperature became 50 ° C. or lower. The obtained powder was 7 ton / cm in a 10 mm square.²According to the orientation conditions shown in Table 4 at a pressure of 5 ° C., no orientation magnetic field was applied, or molding was performed in a perpendicular magnetization of 1.2 MA / m. After molding, the epoxy resin is immersed in a vacuum chamber at 150 ° C. for 1 hour in an Ar atmosphere (O₂The concentration was 0.1% or less. Table 4 shows the magnetic properties of the bonded magnet at this time. In Table 4, No. FIG. 1 shows the changes over time in the magnetic properties of the 14 samples in the 100 ° C. atmosphere. FIG. 1 shows the rate of decrease in (BH) max that changes with time. The case of the present invention molded before hydrogenation / recrystallization treatment is indicated by a solid line, and after hydrogenation / recrystallization treatment. 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]
【The invention's effect】
The present invention relates to a method for producing an R-T-B bond magnet by a hydrogenation / recrystallization treatment method, after molding a powder obtained by hydrogen pulverization or molding in a magnetic field,In the obtained molded bodyHydrogenated and recrystallized, and after the treatment, the molded body is continued,In the molded bodyIt is characterized by being bonded by impregnating or immersing the bonding resin, and the molded body can be maintained even after hydrogenation and recrystallization treatment. An RTB-based anisotropic bonded magnet having a squareness of a demagnetizing curve can be obtained.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the passage of time and the rate of decrease in (BH) max.

Claims (4)

R-T-B alloy ingots are coarsely pulverized to an average particle size of 50 μm to 500 μm by the hydrogen occlusion / disintegration method, and this coarsely pulverized powder is molded into a predetermined shape, and then the obtained compact is subjected to hydrogenation / recrystallization treatment. subjected, subsequently cooled to obtain immersed in impregnation or the resin bonding resin to said molded body, which manufacturing method of an R-T-B type anisotropic bonded magnet to be processed bond reduction. The method of manufacturing an R-T-B type anisotropic bonded magnet according to claim 1, wherein the forming is performed in a magnetic field. 3. The RTB-based alloy ingot according to claim 1 or 2, wherein R: 10 to 20 at% (R: at least one rare earth element including Y and one or two of Pr or Nd). Including 50% or more of R), T: 67 to 85 at% (T: Fe or a part of Fe is replaced with 50% or less of Co), B: 4 to 10 at%. A method for producing an isotropic bonded magnet. 3. The RTB-based alloy ingot according to claim 1 or 2, wherein R: 10 to 20 at% (R: at least one of rare earth elements including Y and one or two of Pr or Nd). Is contained at 50% or more of R), T: 67 to 85 at% (T: Fe or a part of Fe is substituted with 50% or less of Co), B: 4 to 10 at%, M: 10 at% or less (M: Of an R-T-B system anisotropic bonded magnet made of Al, Ti, V, Cr, Ni, Ga, Zr, Nb, Mo , In, Sn, Hf, Ta, or W ). Production method.

Images