JP2020120101A - Method for manufacturing r-t-b based sintered magnet - Google Patents

Abstract

To provide a method for manufacturing an R-T-B based sintered magnet having high Band high H, which can decrease a use amount of RH.SOLUTION: The manufacturing method comprises the steps of: preparing a magnet material; preparing an RL1-RH-M1 based alloy; preparing an RL2-M2 based alloy; first diffusion; and second diffusion. In the first diffusion step, the amount of deposition of the RL1-RH-M1 based alloy is 4 or more and 15 mass% or less. In the second diffusion step, the amount of deposition of the RL2-M2 based alloy is 1 or more and 15 mass% or less. In the magnet material, the content of R is 27 or more and 35 mass% or less; and the molar ratio of [T]/[B] is over 14.0 up to 15.0. In the RL1-RH-M1 based alloy, the content of RL1 is 60 or more and 97 mass% or less, the content of RH is 1 or more and 8 mass% or less, and the content of M1 is 2 or more and 39 mass% or less. In the RL2-M2 based alloy, the content of RL2 is 60 or more and 97 mass% or less, and the content of M2 is 3 or more and 40 mass% or less.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing an RTB-based sintered magnet.

The R-T-B system sintered magnet (R is at least one of rare earth elements, T is mainly Fe, and B is boron) is known as the most high-performance magnet among permanent magnets. It is used in various motors such as voice coil motors (VCM) for hard disk drives, motors for electric vehicles (EV, HV, PHV, etc.), motors for industrial equipment, and home electric appliances.

The RTB sintered magnet is mainly composed of a main phase mainly composed of an R ₂ T ₁₄ B compound and a grain boundary phase located at a grain boundary portion of the main phase. The R ₂ T ₁₄ B compound, which is the main phase, is a ferromagnetic material having a high saturation magnetization and an anisotropic magnetic field, and forms the basis of the characteristics of the RTB sintered magnet.

The _RTB sintered magnet has a problem that irreversible thermal demagnetization occurs because the coercive force _HcJ (hereinafter, simply referred to as " _HcJ ") decreases at high temperature. Therefore, in a particularly R-T-B based sintered magnet used in an electric vehicle motor, having a high H _cJ even at high temperatures, that is, required to have a higher H _cJ at room temperature.

International Publication No. 2007/102391 International Publication No. 2016/133071

It is known that when the light rare earth element (mainly Nd, Pr) in the R ₂ T ₁₄ B type compound phase is replaced with a heavy rare earth element (mainly Dy, Tb), H _cJ is improved. However, there is a problem that the residual magnetic flux density B _r (hereinafter, simply referred to as “B _r ”) is reduced because the saturation magnetization of the R ₂ T ₁₄ B type compound phase is reduced while the H _cJ is improved.

Patent Document 1 describes that a heavy rare earth element such as Dy is supplied to the surface of a sintered magnet of an RTB-based alloy and the heavy rare earth element is diffused inside the sintered magnet. In the method described in Patent Document 1, Dy is diffused from the surface of the RTB-based sintered magnet to the inside to concentrate Dy only in the outer shell portion of the main phase crystal grains effective for improving _HcJ . it makes while suppressing a decrease in _{B r,} it is possible to obtain a high _{H cJ.}

In Patent Document 2, an R-Ga-Cu alloy having a specific composition is brought into contact with the surface of the R-T-B system sintered body to perform heat treatment, whereby grain boundaries in the R-T-B system sintered magnet are obtained. Controlling the phase composition and thickness to improve H _cJ is described.

However, in recent years, it has been required to obtain higher H _cJ while reducing the amount of heavy rare earth elements used, especially in motors for electric vehicles.

Various embodiments of the present disclosure, while reducing the amount of heavy rare earth elements, to provide a method of manufacturing a R-T-B based sintered magnet having a high B _r and high H _cJ.

In an exemplary embodiment, a method for manufacturing an RTB-based sintered magnet according to the present disclosure includes a step of preparing an RTB-based sintered magnet material and an RL1-RH-M1 alloy. A step, a step of preparing an RL2-M2 system alloy, at least a part of the RL1-RH-M1 system alloy is attached to at least a part of the surface of the RTB system sintered magnet material, and a vacuum is applied. Alternatively, in an inert gas atmosphere, a first diffusion step of heating at a temperature of 700° C. or higher and 1100° C. or lower, and at least a part of the surface of the RTB-based sintered magnet material on which the first diffusion step is performed. A second diffusion step in which at least a part of the RL2-M2 alloy is attached and heated at a temperature of 400° C. or more and 600° C. or less in a vacuum or an inert gas atmosphere, The amount of the RL1-RH-M1 system alloy adhered to the R-T-B system sintered magnet material is 4 mass% or more and 15 mass% or less, and the R-T-B system composed of the RL1-RH-M1 system alloy. The amount of RH adhering to the sintered magnet material is 0.1 mass% or more and 0.6 mass% or less, and to the RTB-based sintered magnet material in which the first diffusion step in the second diffusion step is performed. The amount of the RL2-M2 alloy deposited is 1 mass% or more and 15 mass% or less, and in the RTB-based sintered magnet material, R is a rare earth element and is selected from the group consisting of Nd, Pr and Ce. The content of R is always 27 mass% or more and 35 mass% or less of the entire RTB-based sintered magnet material, and T is composed of Fe, Co, Al, Mn, and Si. It is at least one selected from the group, T always contains Fe, the content of Fe with respect to the entire T is 80 mass% or more, and the molar ratio of [T]/[B] is more than 14.0 and 15.0. In the RL1-RH-M1 based alloy, RL1 is at least one of light rare earth elements, and at least one selected from the group consisting of Nd, Pr and Ce is necessarily included, and RL1 is contained. The amount is 60 mass% or more and 97 mass% or less of the entire RL1-RH-M1 alloy, RH is at least one selected from the group consisting of Tb, Dy and Ho, and the content of RH is RL1- It is 1 mass% or more and 8 mass% or less of the entire RH-M1 alloy, M1 is at least one selected from the group consisting of Cu, Ga, Fe, Co, Ni, and Al, and the content of M1 is: RL1-RH-M1 series alloy It is 2 mass% or more and 39 mass% or less of the whole, and in the RL2-M2 alloy, RL2 is at least one of light rare earth elements, and at least one selected from the group consisting of Nd, Pr and Ce is indispensable. The content of RL2 is 60 mass% or more and 97 mass% or less of the entire RL2-M2 alloy, and M2 is at least one selected from the group consisting of Cu, Ga, Fe, Co, Ni, and Al. The content of M2 is 3 mass% or more and 40 mass% or less of the entire RL2-M2 alloy.

In one embodiment, in the RL1-RH-M1 series alloy, the RH content is 2 mass% or more and 6 mass% or less of the entire RL1-RH-M1 series alloy.

In one embodiment, the amount of the RL1-RH-M1 based alloy deposited on the R-T-B based sintered magnet material in the first diffusion step is 5 mass% or more and 10 mass% or less.

In one embodiment, the amount of the RL2-M2 based alloy deposited on the RTB based sintered magnet material in the second diffusion step is 2 mass% or more and 10 mass% or less.

According to embodiments of the present disclosure, while reducing the amount of heavy rare earth elements, it is possible to provide a manufacturing method of the R-T-B based sintered magnet having a high B _r and high H _cJ.

It is sectional drawing which expands a part of RTB type|system|group sintered magnet and shows it as a model. It is sectional drawing which expands the inside of the broken-line rectangular area of FIG. 1A, and is shown typically. 3 is a flowchart showing an example of steps in a method for manufacturing an RTB-based sintered magnet according to the present disclosure.

First, the basic structure of the RTB based sintered magnet according to the present disclosure will be described. R-T-B based sintered magnet, the powder particles of the raw material alloy has a structure bonded by sintering, and a main phase mainly composed of R _{2 T} 14 _B compound grains, the grain boundary portion of the main phase And a grain boundary phase located at.

FIG. 1A is a cross-sectional view schematically showing a part of the R-T-B system sintered magnet in an enlarged manner, and FIG. 1B is a cross-sectional view schematically showing an enlarged view in a broken-line rectangular region in FIG. 1A. Is. In FIG. 1A, for example, an arrow having a length of 5 μm is shown as a reference length indicating a size for reference. As shown in FIGS. 1A and 1B, the RTB-based sintered magnet includes a main phase 12 mainly composed of an R ₂ T ₁₄ B compound and a grain boundary phase 14 located at a grain boundary portion of the main phase 12. It consists of and. In addition, as shown in FIG. 1B, the grain boundary phase 14 includes a two-grain grain boundary phase 14 a in which two R ₂ T ₁₄ B compound particles (grains) are adjacent to each other and three R ₂ T ₁₄ B compound grains in adjacent to each other. Grain boundary triple point 14b. A typical main phase crystal grain size is 3 μm or more and 10 μm or less in average value of the circle equivalent diameter of the magnet cross section. The R ₂ T ₁₄ B compound that is the main phase 12 is a ferromagnetic material having high saturation magnetization and an anisotropic magnetic field. Therefore, in the R-T-B based sintered magnet, it is possible to improve the _{B r} by increasing the existence ratio of _R 2 _{T 14} B compound is the main phase 12. In order to increase the abundance ratio of the R ₂ T ₁₄ B compound, the R content, the T content, and the B content in the raw material alloy are set to the stoichiometric ratio of the R ₂ T ₁₄ B compound (R content:T content:B content= 2:14:1).

Further, by substituting a part of R of the main phase R ₂ T ₁₄ B compound with a heavy rare earth element such as Dy, Tb or Ho, it is possible to increase the anisotropic magnetic field of the main phase while lowering the saturation magnetization. It has been known. In particular, since the main phase shell that is in contact with the two-grain grain boundary phase is likely to become the starting point of the magnetization reversal, the heavy rare earth diffusion technology that can replace the main phase shell with the heavy rare earth element preferentially suppresses the decrease of the saturation magnetization and is efficient. High H _cJ is obtained.

On the other hand, it is known that high H _cJ can also be obtained by controlling the magnetism of the two-particle grain boundary phase 14a. Specifically, by lowering the concentration of magnetic elements (Fe, Co, Ni, etc.) in the two-grain grain boundary phase, the two-grain grain boundary phase becomes closer to non-magnetic, and magnetic coupling between the main phases is achieved. It can be weakened to suppress magnetization reversal.

In the method for manufacturing an RTB-based sintered magnet according to the present disclosure, first, an RTB-based sintered magnet material having a specific composition and an RL1-RH-M1 alloy are attached and heat treatment is performed. Then, RL1, RH, and M1 are diffused from the RL1-RH-M1 alloy into the inside of the magnet material (first diffusion step). Next, the RTB-based sintered magnet material on which the first diffusion step has been performed and the RL2-M2 alloy are adhered to each other and subjected to heat treatment, thereby removing RL2 and M2 from the RL2-M2 alloy. Further, it is diffused inside the magnet material (second diffusion step). As a result of the study by the present inventor, in the first diffusion step, the content of RH was lowered, and then the adhesion amount on the surface of the RTB-based sintered magnet material was controlled to a relatively large specific range, RH, When all of RL1 and M1 are diffused in the RTB-based sintered magnet material, the anisotropic magnetic field of the outer shell of the main phase is remarkably improved due to diffusion even with a small amount of RH. It was found that the concentration of the magnetic element in the two-grain grain boundary phase remarkably decreases due to the diffusion into the grain boundary phase. Thus, while suppressing a decrease in _{B r,} it is possible to obtain a high _{H cJ.} Then, as a result of further examination, after diffusing RL1 and M1 together with RH in the first diffusion step in this way, this time, instead of RH, RL2 and M2 are diffused at a specific temperature different from the first diffusion step. It was found that higher H _cJ can be obtained by performing the second diffusion step. And it turned out that the effect by this 2nd diffusion process is acquired when it applies to the RTB system sintered magnet raw material of a specific composition of this indication.

As shown in FIG. 2, the method for manufacturing an RTB-based sintered magnet according to the present disclosure includes a step S10 of preparing an RTB-based sintered magnet material and an RL1-RH-M1 based alloy. It includes a step S20 and a step S21 of preparing an RL2-M2 alloy. The order of the step S10 of preparing the RTB-based sintered magnet material, the step S20 of preparing the RL1-RH-M1 alloy, and the step S21 of preparing the RL2-M2 alloy is arbitrary and at different places. You may use the manufactured RTB type|system|group sintered magnet raw material, RL1-RH-M1 type|system|group alloy, and RL2-M2 alloy. As shown in FIG. 2, the method for manufacturing an RTB-based sintered magnet according to the present disclosure further includes an RL1-RH-M1-based alloy on at least a part of the surface of the RTB-based sintered magnet material. A first diffusion step S30 in which at least a part is attached and heated at a temperature of 700° C. or more and 1100° C. or less in a vacuum or an inert gas atmosphere, and an RTB-based sintered magnet material on which the first diffusion step is performed A second diffusion step S31 in which at least a part of the RL2-M2 alloy is attached to at least a part of the surface of and the heating is performed at a temperature of 400° C. or more and 600° C. or less in a vacuum or an inert gas atmosphere.

In the present disclosure, the R-T-B system sintered magnet before the second diffusion process and during the second diffusion process is referred to as "R-T-B system sintered magnet material", and R after the second diffusion process. The -T-B system sintered magnet is simply referred to as "R-T-B system sintered magnet".

(Process of preparing an RTB-based sintered magnet material)
In the R-T-B system sintered magnet material, R is a rare earth element and always contains at least one selected from the group consisting of Nd, Pr and Ce, and the content of R is the R-T-B system. It is not less than 27 mass% and not more than 35 mass% of the whole sintered magnet material. T is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, T always contains Fe, and the content of Fe with respect to the entire T is 80 mass% or more, [T]/ The molar ratio of [B] is more than 14.0 and 15.0 or less.

When R is less than 27 mass %, a liquid phase is not sufficiently generated in the sintering process, and it may be difficult to sufficiently densify the sintered body. On the other hand, if R exceeds 35 mass%, grain growth may occur during sintering and H _cJ may decrease. R is preferably 28 mass% or more and 33 mass% or less.

[T]/[B] in the present disclosure is at least one element selected from the group consisting of each element (Fe, Co, Al, Mn, and Si) constituting T, and T always contains Fe, and T The analytical value (mass%) of Fe content with respect to the whole of 80 mass% or more was divided by the atomic weight of each element, and the sum of these values (a) and the analytical value of B (mass) were obtained. %) is the ratio (a/b) to that obtained by dividing the atomic weight of B by (b). The condition that the molar ratio [T]/[B] exceeds 14.0 is that the content of B is smaller than the stoichiometric composition ratio of the R ₂ T ₁₄ B compound, that is, the main phase (R ₂ T ₁₄ It is shown that the amount of B is relatively small with respect to the amount of T used for forming the (B compound). When the [T]/[B] mol ratio is 14.0 or less, a high H _cJ improving effect cannot be obtained even if the second diffusion step is performed. On the other hand, if the [T]/[B] mol ratio exceeds 15.0, _Br may decrease. The molar ratio [T]/[B] is preferably 14.3 or more and 15.0 or less. It is possible to obtain a higher _{B r} and a high _{H cJ.} The content of B is preferably 0.9 mass% or more and less than 1.0 mass% of the entire RTB-based sintered body.

The RTB-based sintered magnet material has, for example, the following composition range.
R: 27-35 mass%,
B: 0.80 to 1.00 mass%,
Ga: 0 to 1.0 mass%,
X: 0 to 2 mass% (X is at least one of Cu, Nb, and Zr),
T: 60 mass% or more,
The molar ratio [T]/[B] is more than 14.0 and 15.0 or less.

The R-T-B system sintered magnet material can be prepared by using a general method for manufacturing a R-T-B system sintered magnet represented by an Nd-Fe-B system sintered magnet. As an example, a raw material alloy produced by a strip casting method or the like is crushed to a size of 3 μm or more and 10 μm or less by using a jet mill or the like, then molded in a magnetic field and sintered at a temperature of 900° C. or more and 1100° C. or less It can be prepared.

(Process of preparing RL1-RH-M1 series alloy)
In the RL1-RH-M1 based alloy, RL1 is at least one of the light rare earth elements, and always contains at least one selected from the group consisting of Nd, Pr and Ce, and the content of RL1 is RL1-. It is 60 mass% or more and 97 mass% or less of the entire RH-M1 alloy. Examples of the light rare earth element include La, Ce, Pr, Nd, Pm, Sm and Eu. RH is at least one selected from the group consisting of Tb, Dy, and Ho, and the content of RH is 1 mass% or more and 8 mass% or less of the entire RL1-RH-M1 alloy. M1 is at least one selected from the group consisting of Cu, Ga, Fe, Co, Ni, and Al, and the content of M1 is 2 mass% or more and 39 mass% or less of the entire RL1-RH-M1 alloy. is there. Typical examples of the RL1-RH-M1 alloy are TbNdPrCu alloy, TbNdCePrCu alloy, TbNdGa alloy, TbNdPrGaCu alloy and the like. Further, RH fluorides, oxides, oxyfluorides and the like may be prepared together with the RL1-M1 alloy. Examples of RH fluorides, oxides, and acid fluorides include TbF ₃ , DyF ₃ , Tb ₂ O ₃ , Dy ₂ O ₃ , Tb ₄ OF, and Dy ₄ OF.

The RL1-RH-M1 alloy contains a small amount (for example, about 2 mass% in total) of an element other than the above-mentioned elements (for example, about 2 mass% in total) by adjusting the contents of RL1, RH, and M1. Good.

When RL1 is less than 60 mass%, RH and M1 are less likely to be introduced into the R-T-B based sintered magnet material, and H _cJ may decrease, and when more than 97 mass%, RL1-RH-M1. The alloy powder becomes very active during the manufacturing process of the base alloy. As a result, there is a possibility that remarkable oxidation or ignition of the alloy powder may occur. Preferably, the content of RL1 is 70 mass% or more and 95 mass% or less of the entire RL1-RH-M1 alloy. Higher H _cJ can be obtained.

When RH is less than 1 mass %, the H _cJ improving effect by RH may not be obtained, and when it exceeds 8 mass %, the H _cJ improving effect by RL1 and M1 may be reduced, so that the heavy rare earth element while reducing the amount of use, it may be impossible to obtain a R-T-B based sintered magnet having a high B _r and high H _cJ. Preferably, the content of RH is 2 mass% or more and 6 mass% or less of the entire RL1-RH-M1 based alloy. It is possible to obtain a higher _{B r} and a high _{H cJ.}

If M1 is less than 2 mass%, RL1 and RH are less likely to be introduced into the two-grain grain boundary phase, and H _cJ may not be sufficiently improved, and if it exceeds 39 mass%, the content of RL1 and RH is reduced and H _cJ may not be sufficiently improved. Preferably, the content of M is 3 mass% or more and 28 mass% or less of the entire RL1-RH-M1 based alloy. Higher H _cJ can be obtained. Further, M1 preferably contains Ga, and further preferably contains Cu. Higher H _cJ can be obtained.

The method for producing the RL1-RH-M1 alloy is not particularly limited. It may be manufactured by a roll quenching method or a casting method. Further, these alloys may be crushed to form alloy powder. It may be produced by a known atomizing method such as a centrifugal atomizing method, a rotating electrode method, a gas atomizing method, or a plasma atomizing method.

(Process of preparing RL2-M2 alloy)
In the RL2-M2 series alloy, RL2 is at least one of the light rare earth elements and always contains at least one selected from the group consisting of Nd, Pr and Ce, and the content of RL2 is RL2-M2 series. It is 60 mass% or more and 97 mass% or less of the entire alloy, M2 is at least one selected from the group consisting of Cu, Ga, Fe, Co, Ni, and Al, and the content of M2 is RL2-M2 system. It is 3 mass% or more and 40 mass% or less of the entire alloy. Typical examples of the RL2-M2 alloy are NdPrCu alloy, NdCePrCu alloy, NdGa alloy, NdPrGaCu alloy and the like.

The RL2-M2 alloy may contain a small amount of elements (for example, about 2 mass% in total) other than the above-described elements by adjusting the contents of RL2 and M2.

When RL2 is less than 60 mass%, it becomes difficult for M1 to be introduced into the R-T-B based sintered magnet material, and _HcJ may decrease. When it exceeds 97 mass%, production of RL2-M2 alloy The alloy powder during the process becomes very active. As a result, there is a possibility that remarkable oxidation or ignition of the alloy powder may occur. Preferably, the content of RL2 is 70 mass% or more and 95 mass% or less of the entire RL2-M2 alloy. Higher H _cJ can be obtained.

If M2 is less than 3 mass%, RL2 becomes difficult to be introduced into the two-grain grain boundary phase, and H _cJ may not be sufficiently improved, and if it exceeds 40 mass%, the content of RL2 is decreased and H _cJ is sufficiently reduced. It may not improve. Preferably, the content of M2 is 3 mass% or more and 28 mass% or less of the entire RL2-M2 alloy. Higher H _cJ can be obtained. Further, M2 preferably contains Ga, and more preferably contains Cu. Higher H _cJ can be obtained.

The method for producing the RL2-M2 alloy is not particularly limited. It may be manufactured by a roll quenching method or a casting method. Further, these alloys may be crushed to form alloy powder. It may be produced by a known atomizing method such as a centrifugal atomizing method, a rotating electrode method, a gas atomizing method, or a plasma atomizing method.

(First diffusion step)
At least a part of the RL1-RH-M1 system alloy prepared as described above is attached to at least a part of the surface of the R-T-B system sintered magnet material prepared as described above, and the temperature is set to 700 in a vacuum or an inert gas atmosphere. The first diffusion step of heating at a temperature of not less than 1°C and not more than 1100°C is performed. As a result, a liquid phase containing RL1, RH, and M1 is generated from the RL1-RH-M1 alloy, and the liquid phase passes from the surface of the sintered material via the grain boundary in the RTB-based sintered magnet material. It is introduced by diffusion inside. The adhesion amount of the RL1-RH-M1 system alloy to the R-T-B system sintered magnet material in the first diffusion step is 4 mass% or more and 15 mass% or less, and the RL1-RH-M1 system alloy is used. The amount of RH adhering to the RTB-based sintered magnet material is set to 0.1 mass% or more and 0.6 mass% or less. This makes it possible to obtain an extremely high H _cJ improving effect. If the amount of the RL1-RH-M1 system alloy deposited on the R-T-B system sintered magnet material is less than 4 mass %, the amount of RH and RL1 and M1 introduced into the magnet material is too small and the high H _cJ may not be obtained, it exceeds 15 mass%, or decreased B _r is much too large, the amount of introduced RH and RL1 and M1, only the amount of the heavy rare earth element is too increased Not only that, the RL1-RH-M1 based alloy that cannot be completely diffused into the magnet may remain on the surface of the magnet, causing another problem such as corrosion resistance and workability. Preferably, the amount of the RL1-RH-M1 based alloy deposited on the R-T-B based sintered magnet material is 5 mass% or more and 10 mass% or less. Higher H _cJ can be obtained. Further, if the amount of RH adhering to the R-T-B based sintered magnet material by the RL1-RH-M1 based alloy is less than 0.1 mass%, the effect of improving _HcJ by RH may not be obtained. However, if it exceeds 0.6 mass %, it is impossible to obtain an _RTB -based sintered magnet having a high H _cJ while reducing the amount of heavy rare earth elements used. Preferably, the amount of RH deposited on the R-T-B based sintered magnet material by the RL1-RH-M1 based alloy is 0.1 mass% or more and 0.5 mass% or less. Here, the attached amount of RH is the amount of RH contained in the RL1-RH-M1 system alloy attached to the R-T-B system sintered magnet material, and the R-T-B system sintered magnet material. Is defined by the mass ratio when the mass of 100 mass% is set.

If the heating temperature in the first diffusion step is lower than 700°C, the amount of liquid phase containing RH, RL1 and M1 may be too small to obtain high H _cJ . On the other hand, if it exceeds 1100° C., H _cJ may be significantly reduced. Preferably, the heating temperature in the diffusion step is 800° C. or higher and 1000° C. or lower. Higher H _cJ can be obtained. Further, preferably, for the RTB-based sintered magnet that has undergone the first diffusion step (700° C. or more and 1100° C. or less), a cooling rate of 15° C./min or more from the temperature at which the first diffusion step is performed. It is preferable to cool to 300°C. Higher H _cJ can be obtained.

The first diffusion step can be performed using a known heat treatment apparatus by placing the RL1-RH-M1 alloy having an arbitrary shape on the surface of the RTB-based sintered magnet material. For example, the surface of the R-T-B based sintered magnet material may be covered with a powder layer of the RL1-RH-M1 alloy, and the first diffusion step may be performed. For example, you may perform the application process of apply|coating a pressure sensitive adhesive to the surface of a coating object, and the process of making RL1-RH-M1 alloy adhere to the area|region where the pressure sensitive adhesive was applied. Examples of the adhesive include PVA (polyvinyl alcohol), PVB (polyvinyl butyral), PVP (polyvinylpyrrolidone), and the like. When the pressure-sensitive adhesive is a water-based pressure-sensitive adhesive, the RTB-based sintered magnet material may be preliminarily heated before coating. The purpose of preheating is to remove excess solvent to control the adhesive strength, and to adhere the adhesive evenly. The heating temperature is preferably 60 to 200°C. This step may be omitted in the case of a highly volatile organic solvent-based pressure-sensitive adhesive. Further, for example, after applying a slurry in which an RL1-RH-M1 alloy is dispersed in a dispersion medium to the surface of an RTB-based sintered magnet material, the dispersion medium is evaporated to evaporate the RL1-RH-M1 alloy and RT. A B-based sintered magnet material may be attached. Examples of the dispersion medium include alcohol (such as ethanol), aldehyde and ketone. Further, RH may be introduced by arranging RH fluoride, oxide, oxyfluoride or the like together with the RL1-M1 alloy on the surface of the RTB-based sintered magnet material. That is, the method is not particularly limited as long as RL1 and M1 can be diffused simultaneously with RH.

Further, if at least a part of the RL1-RH-M1 alloy is attached to at least a part of the RTB-based sintered magnet material, the arrangement position thereof is not particularly limited, but preferably RL1-RH-M1. The alloy is arranged so as to adhere to at least the surface perpendicular to the orientation direction of the RTB-based sintered magnet material. The liquid phase containing RL1, RH and M1 can be more efficiently diffused and introduced from the magnet surface to the inside. In this case, even if the RL1-RH-M1 alloy is adhered only in the orientation direction of the RTB-based sintered magnet material, the RL1-RH-M1 alloy is applied to the entire surface of the RTB-based sintered magnet material. It may be attached.

(Second diffusion step)
At least a part of the RL2-M2 system alloy is attached to at least a part of the surface of the R-T-B system sintered magnet material on which the first diffusion process is performed, and the temperature is set to 400 in a vacuum or an inert gas atmosphere. The second diffusion step of heating at a temperature of ℃ to 600 ℃ is performed. As a result, a liquid phase containing RL2 and M2 is generated from the RL2-M2 alloy, and the liquid phase is diffused and introduced from the surface of the sintered material to the inside via the grain boundary in the RTB-based sintered magnet material. To be done. The amount of the RL2-M2 alloy deposited on the R-T-B sintered magnet material in the second diffusion step is 1 mass% or more and 15 mass% or less. This gives a very high H _cJ . If the amount of adhesion is less than 1 mass %, the amount of RL2 and M2 introduced into the magnet material may be too small to obtain high H _cJ . On the other hand, lowered B _r is much adhesion amount is too large, the amount of introduced RL2 and M2 exceeds 15 mass%, RL2-M2 alloy which can not be diffused to the inside of the magnet remains in the magnet surface, corrosion resistance Ya Another problem such as workability may occur. Preferably, the amount of the RL2-M2 system alloy deposited on the R-T-B system sintered magnet material is 2 mass% or more and 10 mass% or less. Higher H _cJ can be obtained. Further, the R-T-B system sintered magnet material has the above-mentioned range (the content of R is 27 mass% or more and 35 mass% or less of the entire R-T-B system sintered magnet material, and [T]/[B not equal 14.0 ultra 15.0) mol ratio], the second diffusion high _{B r} and a high even when the process to the first diffusion step is the implementation the R-T-B based sintered magnet material _Unable to get H _cJ .

If the heating temperature in the second diffusion step is lower than 400°C, the amount of liquid phase containing RL2 and M2 may be too small to obtain high H _cJ . On the other hand, if it exceeds 600° C., H _cJ may decrease. Preferably, the heating temperature in the diffusion step is 450° C. or higher and 550° C. or lower. Higher H _cJ can be obtained.

In the second diffusion step, similarly to the first diffusion step, an RL2-M2 alloy having an arbitrary shape is arranged on the surface of the RTB-based sintered magnet material on which the first diffusion step has been performed, and a known heat treatment is performed. It can be performed using the device. Further, similar to the first diffusion step, if at least a part of the RL2-M2 alloy is attached to at least a part of the R-T-B system sintered magnet material, its arrangement position is not particularly limited, but preferably , RL2-M2 alloy is arranged so as to adhere to at least the surface perpendicular to the orientation direction of the RTB-based sintered magnet material. The liquid phase containing RL2 and M2 can be more efficiently diffused and introduced from the magnet surface to the inside. In this case, even if the RL2-M2 alloy is adhered only to the orientation direction of the RTB-based sintered magnet material, or the RL2-M2 alloy is adhered to the entire surface of the RTB-based sintered magnet material. Good.

The present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

Experimental example 1
[Step of preparing RTB sintered magnet material (magnet material)]
Each element was weighed and cast by the strip casting method so as to have the composition of the magnet raw material indicated by reference numerals 1-A to 1-D in Table 1, and a flaky raw material alloy having a thickness of 0.2 to 0.4 mm was obtained. It was The obtained flaky raw material alloy was pulverized with hydrogen and then subjected to a dehydrogenation treatment of heating in vacuum to 550° C. and then cooling to obtain coarsely pulverized powder. Next, after adding zinc stearate as a lubricant to the obtained coarsely pulverized powder in an amount of 0.04 mass% with respect to 100 mass% of the coarsely pulverized powder and mixing them, nitrogen was obtained by using an air flow type pulverizer (jet mill device). Dry pulverization was performed in an air stream to obtain finely pulverized powder (alloy powder) having a particle size D ₅₀ of 4 μm. The particle diameter D ₅₀ is a volume center value (volume-based median diameter) obtained by a laser diffraction method using an air flow dispersion method.

Zinc stearate as a lubricant was added to the finely pulverized powder in an amount of 0.05 mass% with respect to 100 mass% of the finely pulverized powder, and the mixture was molded in a magnetic field to obtain a molded body. A so-called orthogonal magnetic field molding device (transverse magnetic field molding device) in which the magnetic field applying direction and the pressurizing direction are orthogonal to each other was used as the molding device.

The obtained molded body was sintered in vacuum at a temperature of 1000° C. or higher and 1050° C. or lower (a temperature at which sufficient densification by sintering is sufficiently selected is selected for each sample) for 4 hours and then rapidly cooled to obtain a magnet material. The density of the obtained magnet material was 7.5 Mg/m ³ or more. Table 1 shows the results of the components of the obtained magnet material. In addition, each component in Table 1 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES). In addition, as a result of measuring the oxygen content of the magnet material by the gas melting-infrared absorption method, it was confirmed that all were about 0.1 mass %. Moreover, as a result of measuring C (carbon content) using a gas analyzer by a combustion-infrared absorption method, it was confirmed that it was around 0.1 mass %. “[T]/[B]” in Table 1 is obtained by dividing the analytical value (mass %) for each element (Fe, Co, Al, Si, Mn) constituting T by the atomic weight of the element. It is the ratio (a/b) of the value obtained by summing these values (a) and the value obtained by dividing the B analysis value (mass %) by the atomic weight of B (b). The same applies to all the tables below. In addition, even if each composition, oxygen content, and carbon content of Table 1 are added together, it does not become 100 mass %. This is because the analysis method differs depending on each component as described above. The same applies to the other tables.

[Step of preparing RL1-RH-M1 series alloy]
Each element is weighed and the raw materials thereof are melted so as to have the composition of the RL1-RH-M1 series alloy shown by reference numeral 1-a1 in Table 2, and ribbons or flakes are prepared by a single roll ultra-quenching method (melt spinning method). A shaped alloy was obtained. Table 2 shows the composition of the obtained RL1-RH-M1 alloy. In addition, each component in Table 2 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[Process of preparing RL2-M2 alloy]
Each element was weighed and their raw materials were melted so as to have the composition of the RL2-M2 alloy shown by reference numeral 1-a2 in Table 3, and ribbon-shaped or flaky-shaped was formed by the single-roll ultra-quenching method (melt spinning method). An alloy was obtained. Table 3 shows the composition of the obtained RL2-M2 alloy. In addition, each component in Table 3 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[First diffusion step]
Each of the RTB-based sintered magnet materials 1-A to 1-D shown in Table 1 was cut and cut into a cube of 7.2 mm x 7.2 mm x 7.2 mm. PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material by a dipping method on the processed RTB-based sintered magnet material. Next, the RL1-RH-M1 system alloy was adhered to the entire surface of the R-T-B system sintered magnet material coated with the adhesive under the production conditions shown in Table 4. The RL1-RH-M1 alloy deposition amount and the RH deposition amount are obtained by crushing the RL1-RH-M1 alloy in an argon atmosphere using a mortar and then passing through several sieves having openings 38 to 1000 μm. It was adjusted by using RL1-RH-M1 series alloys having different grain sizes. Then, using a vacuum heat treatment furnace, the RL1-RH-M1 system alloy and the R-T-B system sintered magnet material were prepared under reduced pressure argon controlled to 200 Pa under the conditions shown in the first diffusion step of Table 4. After heating, it was cooled.

[Second diffusion step]
PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material on which the first diffusion step was performed again by the dipping method. Then, under the production conditions shown in Table 4, the RL2-M2 alloy was adhered to the entire surface of the RTB-based sintered magnet material on which the first diffusion step in which the adhesive was applied was performed. The RL2-M2 alloy used was one obtained by crushing the RL2-M2 alloy in a mortar in an argon atmosphere and then passing it through a comb having an opening of 300 μm. Then, using a vacuum heat treatment furnace, the RL2-M2 alloy and the RTB in which the first diffusion step was performed under the conditions shown in the second diffusion step of Table 4 in reduced pressure argon controlled to 200 Pa. The sintered magnet material was heated and then cooled. The surface of each sample after the second diffusion treatment was cut using a surface grinder, and a cubic sample of 7.0 mm×7.0 mm×7.0 mm (RTB-based sintering) Got a magnet). In addition, the heating temperature of the RL1-RH-M1 system alloy and the RTB system sintered magnet material in the process of performing the first diffusion process, and the RL2-M2 system alloy and R in the process of performing the second diffusion process. The heating temperature of the -TB sintered magnet material was measured by a thermocouple.

[sample test]
The obtained sample was measured _{B r} and _{H cJ} of each sample by the B-H tracer. The measurement results are shown in Table 4. As shown in Table 4, sample No. The present invention Examples of 1-6～1-10,1-13～1-14 are all while reducing the amount of heavy rare earth elements, it can be seen that obtain a high _{B r} and high _{H cJ.} On the other hand, in the case of the sample No. 1 in which the [T]/[B] mol ratio in the RTB-based sintered magnet material is not more than 14.0 and not more than 15.0. No high H _cJ was obtained in _1-1 to _1-4 . Furthermore, the sample No. in which the adhesion amount of the RL1-RH-M1 alloy is less than 4 mass%. 1-5 and 1-12 did not obtain high _HcJ . In addition, the sample No. 1-11 is higher _{B r} and high _{H cJ} are obtained, the adhesion amount of RL1-RH-M1-based alloy with 15 mass% greater, and RH adhesion amount is 0.6 mass% _{greater, H cJ} increased is less effective _{(H cJ} is not so much improved from No.1-10, _{B r} is decreased). Therefore, while reducing the amount of heavy rare earth elements, it is impossible to obtain a R-T-B based sintered magnet having a high B _r and high H _cJ.

Experimental example 2
[Step of preparing RTB sintered magnet material (magnet material)]
Each element was weighed and cast by the strip casting method so as to have the composition of the magnet raw material indicated by reference numerals 2-A to 2-D in Table 5, and a flaky raw material alloy having a thickness of 0.2 to 0.4 mm was obtained. It was The obtained flaky raw material alloy was pulverized with hydrogen and then subjected to a dehydrogenation treatment of heating in vacuum to 550° C. and then cooling to obtain coarsely pulverized powder. Next, after adding zinc stearate as a lubricant to the obtained coarsely pulverized powder in an amount of 0.04 mass% with respect to 100 mass% of the coarsely pulverized powder and mixing them, nitrogen was obtained by using an air flow type pulverizer (jet mill device). Dry pulverization was performed in an air stream to obtain finely pulverized powder (alloy powder) having a particle size D ₅₀ of 4 μm. The particle diameter D ₅₀ is a volume center value (volume-based median diameter) obtained by a laser diffraction method using an air flow dispersion method.

Zinc stearate as a lubricant was added to the finely pulverized powder in an amount of 0.05 mass% with respect to 100 mass% of the finely pulverized powder, and the mixture was molded in a magnetic field to obtain a molded body. A so-called orthogonal magnetic field molding device (transverse magnetic field molding device) in which the magnetic field applying direction and the pressurizing direction are orthogonal to each other was used as the molding device.

The obtained molded body was sintered in vacuum at a temperature of 1000° C. or higher and 1050° C. or lower (a temperature at which sufficient densification by sintering is sufficiently selected is selected for each sample) for 4 hours and then rapidly cooled to obtain a magnet material. The density of the obtained magnet material was 7.5 Mg/m ³ or more. The results of the components of the obtained magnet material are shown in Table 5. In addition, each component in Table 5 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES). As a result of measuring the oxygen content of the magnet material by the gas melting-infrared absorption method, it was confirmed that all were about 0.1 mass%. Moreover, as a result of measuring C (carbon content) using a gas analyzer by a combustion-infrared absorption method, it was confirmed that it was around 0.1 mass %.

[Step of preparing RL1-RH-M1 series alloy]
Each element is weighed and the raw materials thereof are melted so as to have the composition of the RL1-RH-M1 series alloy shown by symbol 2-a1 in Table 6, and ribbons or flakes are prepared by a single roll ultra-quenching method (melt spinning method). A shaped alloy was obtained. Table 6 shows the composition of the obtained RL1-RH-M1 alloy. In addition, each component in Table 6 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[Process of preparing RL2-M2 alloy]
Each element was weighed and their raw materials were melted so as to have the composition of the RL2-M2 alloy shown by reference numeral 2-a2 in Table 7, and ribbons or flakes were formed by a single roll ultra-quenching method (melt spinning method). An alloy was obtained. Table 7 shows the composition of the obtained RL2-M2 alloy. Each component in Table 7 was measured by using high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[First diffusion step]
Each of the R-T-B based sintered magnet materials indicated by reference numerals 2-A to 2-D in Table 5 was cut and cut into a cube of 7.2 mm x 7.2 mm x 7.2 mm. PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material by a dipping method on the processed RTB-based sintered magnet material. Next, the RL1-RH-M1 system alloy was adhered to the entire surface of the R-T-B system sintered magnet material coated with the adhesive under the production conditions shown in Table 8. The RL1-RH-M1 alloy used was one obtained by crushing the RL1-RH-M1 alloy in an argon atmosphere using a mortar and then passing it through a comb having an opening of 300 μm. Then, using a vacuum heat treatment furnace, the RL1-RH-M1 system alloy and the R-T-B system sintered magnet material were prepared under reduced pressure argon controlled to 200 Pa under the conditions shown in the first diffusion step of Table 8. After heating, it was cooled.

[Second diffusion step]
PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material on which the first diffusion step was performed again by the dipping method. Then, under the manufacturing conditions shown in Table 8, the RL2-M2 alloy was attached to the entire surface of the RTB-based sintered magnet material on which the first diffusion step in which the adhesive was applied was performed (however, sample No. 2-1, 2-2 and 2-6 have no RL2-M2 alloy adhered). As the RL2-M2 alloy, the RL2-M2 alloy is crushed in an argon atmosphere using a mortar and then passed through several kinds of sieves having openings of 300 to 1000 μm to use RL2-M2 alloys having different particle sizes. Adjusted accordingly. Then, using a vacuum heat treatment furnace, the RTB-based sintered magnet material to which the RL2-M2 alloy is attached is heated under reduced pressure argon controlled to 200 Pa under the conditions shown in the second diffusion step of Table 8. After that, it was cooled (however, sample Nos. 2-1, 2-2 and 2-6 were only heated without adhesion of the RL2-M2 alloy). The surface of each sample after the second diffusion treatment was cut using a surface grinder, and a cubic sample of 7.0 mm×7.0 mm×7.0 mm (RTB-based sintering) Got a magnet). In addition, the heating temperature of the RL1-RH-M1 system alloy and the RTB system sintered magnet material in the process of performing the first diffusion process, and the RL2-M2 system alloy and R in the process of performing the second diffusion process. The heating temperature of the -TB sintered magnet material was measured by a thermocouple.

[sample test]
The obtained sample was measured _{B r} and _{H cJ} of each sample by the B-H tracer. The measurement results are shown in Table 8. As shown in Table 8, sample No. The present invention Examples of 2-7～2-13,2-15～2-17 are all while reducing the amount of heavy rare earth elements, it can be seen that obtain a high _{B r} and high _{H cJ.} On the other hand, the [T]/[B] molar ratio in the RTB-based sintered magnet material is not more than 14.0 and 15.0 or less, and the RTB-based sintered magnet material is Sample No. with no RL2-M2 alloy attached. Sample Nos. 2-1 and 2-2, and the [T]/[B] molar ratio in the RTB-based sintered magnet material that is not more than 14.0 and not more than 15.0. In 2-3 to 2-5, high _HcJ was not obtained. Furthermore, sample No. in which the RL2-M2 alloy was not attached to the R-T-B system sintered magnet material. 2-6 did not obtain high H _cJ . In addition, Sample No. 1 having an adhesion amount of the RL2-M2 alloy of more than 15 mass%. 2-14 _{B r} had been significantly reduced.

Experimental example 3
[Step of preparing RTB sintered magnet material (magnet material)]
Each element was weighed and cast by the strip casting method so as to have the composition of the magnet material shown by reference numeral 3-A in Table 9, and a flaky raw material alloy having a thickness of 0.2 to 0.4 mm was obtained. The obtained flaky raw material alloy was pulverized with hydrogen and then subjected to a dehydrogenation treatment of heating in vacuum to 550° C. and then cooling to obtain coarsely pulverized powder. Next, after adding zinc stearate as a lubricant to the obtained coarsely pulverized powder in an amount of 0.04 mass% with respect to 100 mass% of the coarsely pulverized powder and mixing them, nitrogen was obtained by using an air flow type pulverizer (jet mill device). Dry pulverization was performed in an air stream to obtain finely pulverized powder (alloy powder) having a particle size D ₅₀ of 4 μm. The particle diameter D ₅₀ is a volume center value (volume-based median diameter) obtained by a laser diffraction method using an air flow dispersion method.

Zinc stearate as a lubricant was added to the finely pulverized powder in an amount of 0.05 mass% with respect to 100 mass% of the finely pulverized powder, and the mixture was molded in a magnetic field to obtain a molded body. A so-called orthogonal magnetic field molding device (transverse magnetic field molding device) in which the magnetic field applying direction and the pressurizing direction are orthogonal to each other was used as the molding device.

The obtained molded body was sintered in a vacuum for 4 hours (selecting a temperature at which sufficient densification by sintering occurs) and then rapidly cooled to obtain a magnet material. The density of the obtained magnet material was 7.5 Mg/m ³ or more. Table 9 shows the results of the components of the obtained magnetic material. In addition, each component in Table 9 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES). As a result of measuring the oxygen content of the magnet material by the gas melting-infrared absorption method, it was confirmed that all were about 0.1 mass%. Moreover, as a result of measuring C (carbon content) using a gas analyzer by a combustion-infrared absorption method, it was confirmed that it was around 0.1 mass %.

[Step of preparing RL1-RH-M1 series alloy]
Each element was weighed and the raw materials thereof were melted so that the composition of the RL1-RH-M1 series alloy indicated by the reference signs 3-a1 to 3-g1 in Table 10 was obtained, and the single roll ultra-quenching method (melt spinning method) was used. A ribbon or flake alloy was obtained by. Table 10 shows the composition of the obtained RL1-RH-M1 based alloy. In addition, each component in Table 10 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[Process of preparing RL2-M2 alloy]
Each element was weighed and their raw materials were melted so as to have the composition of the RL2-M2 alloy shown by symbol 3-a2 in Table 11, and ribbons or flakes were formed by the single-roll ultra-quenching method (melt spinning method). An alloy was obtained. Table 11 shows the composition of the obtained RL2-M2 alloy. In addition, each component in Table 11 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[First diffusion step]
The R-T-B based sintered magnet material indicated by the reference numeral 3-A in Table 9 was cut and cut into a cube of 7.2 mm x 7.2 mm x 7.2 mm. PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material by a dipping method on the processed RTB-based sintered magnet material. Next, the RL1-RH-M1 system alloy was adhered to the entire surface of the R-T-B system sintered magnet material coated with the adhesive under the production conditions shown in Table 12. The RL1-RH-M1 alloy deposition amount and the RH deposition amount are obtained by crushing the RL1-RH-M1 alloy in an argon atmosphere using a mortar and then passing through several sieves having openings 38 to 1000 μm. It was adjusted by using RL1-RH-M1 series alloys having different grain sizes. Then, using a vacuum heat treatment furnace, the RL1-RH-M1 system alloy and the R-T-B system sintered magnet material were prepared under reduced pressure argon controlled to 200 Pa under the conditions shown in the first diffusion step of Table 12. After heating, it was cooled.

[Second diffusion step]
PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material on which the first diffusion step was performed again by the dipping method. Then, under the manufacturing conditions shown in Table 12, the RL2-M2 alloy was attached to the entire surface of the RTB-based sintered magnet material on which the first diffusion step in which the adhesive was applied was performed. The RL2-M2 alloy used was one obtained by crushing the RL2-M2 alloy in a mortar in an argon atmosphere and then passing it through a comb having an opening of 300 μm. Then, using the vacuum heat treatment furnace, in the reduced pressure argon controlled to 200 Pa, the RL2-M2 alloy and the RTB in which the first diffusion step was performed under the conditions shown in the second diffusion step of Table 12. The sintered magnet material was heated and then cooled. The surface of each sample after the second diffusion treatment was cut using a surface grinder, and a cubic sample of 7.0 mm×7.0 mm×7.0 mm (RTB-based sintering) Got a magnet). In addition, the heating temperature of the RL1-RH-M1 system alloy and the RTB system sintered magnet material in the process of performing the first diffusion process, and the RL2-M2 system alloy and R in the process of performing the second diffusion process. The heating temperature of the -TB sintered magnet material was measured by a thermocouple.

[sample test]
The obtained sample was measured _{B r} and _{H cJ} of each sample by the B-H tracer. The measurement results are shown in Table 12. As shown in Table 12, sample No. The present invention Examples of 3-2～3-6 are all while reducing the amount of heavy rare earth elements, it can be seen that obtain a high B _r and high H _cJ. On the other hand, the sample No. in which the RH amount of the RL1-RH-M1 alloy is less than 1 mass%. 3-1 could not obtain high _HcJ . In addition, the sample No. 3-7 is higher _{B r} and high _{H cJ} are obtained, RH adhesion amount is 0.6 mass% greater Sample No. It has reduced both the _{B r} and _{H cJ} compared to the 3-6. Therefore, while reducing the amount of heavy rare earth elements, it is impossible to obtain a R-T-B based sintered magnet having a high B _r and high H _cJ.

Experimental example 4
[Step of preparing RTB sintered magnet material (magnet material)]
Each element was weighed and cast by the strip casting method so as to have the composition of the magnet raw material shown by the symbol 4-A in Table 13, and a flaky raw material alloy having a thickness of 0.2 to 0.4 mm was obtained. The obtained flaky raw material alloy was pulverized with hydrogen and then subjected to a dehydrogenation treatment of heating in vacuum to 550° C. and then cooling to obtain coarsely pulverized powder. Next, after adding zinc stearate as a lubricant to the obtained coarsely pulverized powder in an amount of 0.04 mass% with respect to 100 mass% of the coarsely pulverized powder and mixing them, nitrogen was obtained by using an air flow type pulverizer (jet mill device). Dry pulverization was performed in an air stream to obtain finely pulverized powder (alloy powder) having a particle size D ₅₀ of 4 μm. The particle diameter D ₅₀ is a volume center value (volume-based median diameter) obtained by a laser diffraction method using an air flow dispersion method.

Zinc stearate as a lubricant was added to the finely pulverized powder in an amount of 0.05 mass% with respect to 100 mass% of the finely pulverized powder, and the mixture was molded in a magnetic field to obtain a molded body. A so-called orthogonal magnetic field molding device (transverse magnetic field molding device) in which the magnetic field applying direction and the pressurizing direction are orthogonal to each other was used as the molding device.

The obtained molded body was sintered in a vacuum for 4 hours (selecting a temperature at which sufficient densification by sintering occurs) and then rapidly cooled to obtain a magnet material. The density of the obtained magnet material was 7.5 Mg/m ³ or more. Table 13 shows the results of the components of the obtained magnetic material. In addition, each component in Table 13 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES). As a result of measuring the oxygen content of the magnet material by the gas melting-infrared absorption method, it was confirmed that all were about 0.1 mass%. Moreover, as a result of measuring C (carbon content) using a gas analyzer by a combustion-infrared absorption method, it was confirmed that it was around 0.1 mass %.

[Step of preparing RL1-RH-M1 series alloy]
Each element is weighed and the raw materials thereof are melted so as to have the composition of the RL1-RH-M1 series alloy shown by symbol 4-a1 in Table 14, and ribbons or flakes are formed by a single roll ultra-quenching method (melt spinning method). A shaped alloy was obtained. Table 14 shows the composition of the obtained RL1-RH-M1 based alloy. In addition, each component in Table 14 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[Process of preparing RL2-M2 alloy]
Each element was weighed and their raw materials were melted so as to have the composition of the RL2-M2 series alloy shown by the symbol 4-a2 in Table 15, and ribbons or flakes were formed by the single roll ultra-quenching method (melt spinning method). An alloy was obtained. Table 15 shows the composition of the obtained RL2-M2 alloy. Each component in Table 15 was measured using a high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[First diffusion step]
The RTB-based sintered magnet material of 4-A in Table 13 was cut and cut into a cube of 7.2 mm×7.2 mm×7.2 mm. PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material by a dipping method on the processed RTB-based sintered magnet material. Next, the RL1-RH-M1 system alloy was adhered to the entire surface of the R-T-B system sintered magnet material coated with the adhesive under the production conditions shown in Table 16. The RL1-RH-M1 alloy used was one obtained by crushing the RL1-RH-M1 alloy in an argon atmosphere using a mortar and then passing it through a comb having an opening of 300 μm. Then, using a vacuum heat treatment furnace, the RL1-RH-M1 system alloy and the R-T-B system sintered magnet material were prepared under reduced pressure argon controlled to 200 Pa under the conditions shown in the first diffusion step of Table 16. After heating, it was cooled.

[Second diffusion step]
PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material on which the first diffusion step was performed again by the dipping method. After that, under the production conditions shown in Table 16, the RL2-M2 alloy was attached to the entire surface of the RTB-based sintered magnet material on which the first diffusion step in which the adhesive was applied was performed. The RL2-M2 alloy used was one obtained by crushing the RL2-M2 alloy in a mortar in an argon atmosphere and then passing it through a comb having an opening of 300 μm. Then, using the vacuum heat treatment furnace, the RL2-M2 alloy and the R-T-B in which the first diffusion process was performed under the conditions shown in the second diffusion process of Table 16 in depressurized argon controlled to 200 Pa. The sintered magnet material was heated and then cooled. The surface of each sample after the second diffusion treatment was cut using a surface grinder, and a cubic sample of 7.0 mm×7.0 mm×7.0 mm (RTB-based sintering) Got a magnet). In addition, the heating temperature of the RL1-RH-M1 system alloy and the RTB system sintered magnet material in the process of performing the first diffusion process, and the RL2-M2 system alloy and R in the process of performing the second diffusion process. The heating temperature of the -TB sintered magnet material was measured by a thermocouple.

[sample test]
The obtained sample was measured _{B r} and _{H cJ} of each sample by the B-H tracer. The measurement results are shown in Table 16. As shown in Table 16, sample No. The present invention Examples of 4-2～4-8 are all while reducing the amount of heavy rare earth elements, it can be seen that obtain a high B _r and high H _cJ. On the other hand, sample No. 1 having a treatment temperature of less than 700° C. in the first diffusion step. No high H _cJ was obtained for 4-1. In addition, in the sample No. 1 having a treatment temperature in the first diffusion step of more than 1100°C. High _HcJ was not obtained even for 4-9.

Experimental example 5
[Step of preparing RTB sintered magnet material (magnet material)]
Each element was weighed and cast by a strip casting method so as to have the composition of the magnet material shown by the symbol 5-A in Table 17, and a flaky raw material alloy having a thickness of 0.2 to 0.4 mm was obtained. The obtained flaky raw material alloy was pulverized with hydrogen and then subjected to a dehydrogenation treatment of heating in vacuum to 550° C. and then cooling to obtain coarsely pulverized powder. Next, after adding zinc stearate as a lubricant to the obtained coarsely pulverized powder in an amount of 0.04 mass% with respect to 100 mass% of the coarsely pulverized powder and mixing them, nitrogen was obtained by using an air flow type pulverizer (jet mill device). Dry pulverization was performed in an air stream to obtain finely pulverized powder (alloy powder) having a particle size D ₅₀ of 4 μm. The particle diameter D ₅₀ is a volume center value (volume-based median diameter) obtained by a laser diffraction method using an air flow dispersion method.

Zinc stearate as a lubricant was added to the finely pulverized powder in an amount of 0.05 mass% with respect to 100 mass% of the finely pulverized powder, and the mixture was molded in a magnetic field to obtain a molded body. A so-called orthogonal magnetic field molding device (transverse magnetic field molding device) in which the magnetic field applying direction and the pressurizing direction are orthogonal to each other was used as the molding device.

The obtained molded body was sintered in a vacuum for 4 hours (selecting a temperature at which sufficient densification by sintering occurs) and then rapidly cooled to obtain a magnet material. The density of the obtained magnet material was 7.5 Mg/m ³ or more. Table 17 shows the results of the components of the obtained magnet material. In addition, each component in Table 17 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES). In addition, as a result of measuring the oxygen content of the magnet material by the gas melting-infrared absorption method, it was confirmed that all were about 0.1 mass %. Moreover, as a result of measuring C (carbon content) using a gas analyzer by a combustion-infrared absorption method, it was confirmed that it was around 0.1 mass %.

[Step of preparing RL1-RH-M1 series alloy]
Each element is weighed and the raw materials thereof are melted so as to have the composition of the RL1-RH-M1 series alloy shown by the symbol 5-a1 in Table 18, and ribbons or flakes are prepared by a single roll ultra-quenching method (melt spinning method). A shaped alloy was obtained. Table 18 shows the composition of the obtained RL1-RH-M1 alloy. In addition, each component in Table 18 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[Process of preparing RL2-M2 alloy]
Each element was weighed and the raw materials thereof were melted so as to have the composition of the RL-RH-M alloy shown by the symbol 5-a2 in Table 19, and ribbons or flakes were formed by a single roll ultra-quenching method (melt spinning method). A shaped alloy was obtained. Table 19 shows the composition of the obtained RL-RH-M alloy. In addition, each component in Table 19 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[First diffusion step]
The R-T-B based sintered magnet material with the code 5-A in Table 17 was cut and cut into a cube of 7.2 mm x 7.2 mm x 7.2 mm. PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material by a dipping method on the processed RTB-based sintered magnet material. Next, the RL1-RH-M1 system alloy was adhered to the entire surface of the R-T-B system sintered magnet material coated with the adhesive under the production conditions shown in Table 19. The RL1-RH-M1 alloy used was one obtained by crushing the RL1-RH-M1 alloy in an argon atmosphere using a mortar and then passing it through a comb having an opening of 300 μm. Then, using a vacuum heat treatment furnace, the RL1-RH-M1 system alloy and the R-T-B system sintered magnet material were prepared under reduced pressure argon controlled to 200 Pa under the conditions shown in the first diffusion step of Table 19. After heating, it was cooled.

[Second diffusion step]
PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material on which the first diffusion step was performed again by the dipping method. Then, under the manufacturing conditions shown in Table 19, the RL2-M2 alloy was attached to the entire surface of the RTB-based sintered magnet material on which the first diffusion step in which the adhesive was applied was performed. The RL2-M2 alloy used was one obtained by crushing the RL2-M2 alloy in a mortar in an argon atmosphere and then passing it through a comb having an opening of 300 μm. Then, using a vacuum heat treatment furnace, the RL2-M2 alloy and the R-T-B in which the first diffusion process was performed under the conditions shown in the second diffusion process of Table 19 in reduced pressure argon controlled to 200 Pa. The sintered magnet material was heated and then cooled. The surface of each sample after the second diffusion treatment was cut using a surface grinder, and a cubic sample of 7.0 mm×7.0 mm×7.0 mm (RTB-based sintering) Got a magnet). In addition, the heating temperature of the RL1-RH-M1 system alloy and the RTB system sintered magnet material in the process of performing the first diffusion process, and the RL2-M2 system alloy and R in the process of performing the second diffusion process. The heating temperature of the -T-B system sintered magnet material was measured by a thermocouple.

[sample test]
The obtained sample was measured _{B r} and _{H cJ} of each sample by the B-H tracer. Table 20 shows the measurement results. As shown in Table 20, sample No. The present invention Examples of 5-2～5-8 are all while reducing the amount of heavy rare earth elements, it can be seen that obtain a high B _r and high H _cJ. On the other hand, sample No. 2 whose processing temperature in the second diffusion step is less than 400°C. 5-1 did not obtain high H _cJ . In addition, the sample No. 1 having a treatment temperature of the second diffusion step of higher than 600° C. High _HcJ was not obtained even in 5-9.

Experimental example 6
[Step of preparing RTB sintered magnet material (magnet material)]
Each element was weighed and cast by the strip casting method so as to have the composition of the magnet material shown by 6-A in Table 21, and a flaky raw material alloy having a thickness of 0.2 to 0.4 mm was obtained. The obtained flaky raw material alloy was pulverized with hydrogen and then subjected to a dehydrogenation treatment of heating in vacuum to 550° C. and then cooling to obtain coarsely pulverized powder. Next, after adding zinc stearate as a lubricant to the obtained coarsely pulverized powder in an amount of 0.04 mass% with respect to 100 mass% of the coarsely pulverized powder and mixing them, nitrogen was obtained by using an air flow type pulverizer (jet mill device). Dry pulverization was performed in an air stream to obtain finely pulverized powder (alloy powder) having a particle size D ₅₀ of 4 μm. The particle diameter D ₅₀ is a volume center value (volume-based median diameter) obtained by a laser diffraction method using an air flow dispersion method.

Zinc stearate as a lubricant was added to the finely pulverized powder in an amount of 0.05 mass% with respect to 100 mass% of the finely pulverized powder, and the mixture was molded in a magnetic field to obtain a molded body. A so-called orthogonal magnetic field molding device (transverse magnetic field molding device) in which the magnetic field applying direction and the pressurizing direction are orthogonal to each other was used as the molding device.

The obtained molded body was sintered in a vacuum for 4 hours (selecting a temperature at which sufficient densification by sintering occurs) and then rapidly cooled to obtain a magnet material. The density of the obtained magnet material was 7.5 Mg/m ³ or more. Table 21 shows the results of the components of the obtained magnetic material. In addition, each component in Table 21 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES). In addition, as a result of measuring the oxygen content of the magnet material by the gas melting-infrared absorption method, it was confirmed that all were about 0.1 mass %. Moreover, as a result of measuring C (carbon content) using a gas analyzer by a combustion-infrared absorption method, it was confirmed that it was around 0.1 mass %.

[Step of preparing RL1-RH-M1 series alloy]
Each element is weighed and the raw materials thereof are melted so as to have the composition of the RL1-RH-M1 series alloy shown by the reference numeral 6-a1 in Table 22, and ribbons or flakes are prepared by the single-roll ultra-quenching method (melt spinning method). A shaped alloy was obtained. Table 22 shows the composition of the obtained RL1-RH-M1 alloy. In addition, each component in Table 22 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[Process of preparing RL2-M2 alloy]
Each element was weighed and the raw materials thereof were melted so as to have the composition of the RL2-M2 series alloy shown by the reference numeral 6-a2 in Table 23, and ribbons or flakes were formed by the single roll ultra-quenching method (melt spinning method). An alloy was obtained. Table 23 shows the composition of the obtained RL2-M2 alloy. In addition, each component in Table 23 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[First diffusion step]
The RTB sintered magnet material of 6-A in Table 21 was cut and cut into a cube of 7.2 mm×7.2 mm×7.2 mm. PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material by a dipping method on the processed RTB-based sintered magnet material. Next, the RL1-RH-M1 system alloy was adhered to the entire surface of the R-T-B system sintered magnet material coated with the adhesive under the production conditions shown in Table 24. The RL1-RH-M1 alloy used was one obtained by crushing the RL1-RH-M1 alloy in an argon atmosphere using a mortar and then passing it through a comb having an opening of 300 μm. Then, using a vacuum heat treatment furnace, the RL1-RH-M1 system alloy and the R-T-B system sintered magnet material were prepared under reduced pressure argon controlled to 200 Pa under the conditions shown in the first diffusion step of Table 24. After heating, it was cooled.

[Second diffusion step]
PVA as an adhesive was applied to the entire surface of the RTB-based sintered magnet material on which the first diffusion step was performed again by the dipping method. Then, under the production conditions shown in Table 24, the RL2-M2 alloy was adhered to the entire surface of the RTB-based sintered magnet material on which the first diffusion step in which the adhesive was applied was performed. The RL2-M2 alloy used was one obtained by crushing the RL2-M2 alloy in a mortar in an argon atmosphere and then passing it through a comb having an opening of 300 μm. Then, using a vacuum heat treatment furnace, in the reduced pressure argon controlled to 200 Pa, the RL2-M2 alloy and the R-T-B in which the first diffusion process was performed under the conditions shown in the second diffusion process of Table 24. The sintered magnet material was heated and then cooled. The surface of each sample after the second diffusion treatment was cut using a surface grinder, and a cubic sample of 7.0 mm×7.0 mm×7.0 mm (RTB-based sintering) Got a magnet). In addition, the heating temperature of the RL1-RH-M1 system alloy and the RTB system sintered magnet material in the process of performing the first diffusion process, and the RL2-M2 system alloy and R in the process of performing the second diffusion process. The heating temperature of the -TB sintered magnet material was measured by a thermocouple.

[sample test]
The obtained sample was measured _{B r} and _{H cJ} of each sample by the B-H tracer. The measurement results are shown in Table 24. As shown in Table 24, sample No. The present invention example 6-1, while reducing the amount of heavy rare earth elements, it can be seen that obtain a high B _r and high H _cJ.

Experimental example 7
[Step of preparing RTB sintered magnet material (magnet material)]
Each element was weighed and cast by a strip casting method so as to have the composition of the magnet raw material shown by 6-A in Table 25, and a flaky raw material alloy having a thickness of 0.2 to 0.4 mm was obtained. The obtained flaky raw material alloy was pulverized with hydrogen and then subjected to a dehydrogenation treatment of heating in vacuum to 550° C. and then cooling to obtain coarsely pulverized powder. Next, after adding zinc stearate as a lubricant to the obtained coarsely pulverized powder in an amount of 0.04 mass% with respect to 100 mass% of the coarsely pulverized powder and mixing them, nitrogen was obtained by using an air flow type pulverizer (jet mill device). Dry pulverization was performed in an air stream to obtain finely pulverized powder (alloy powder) having a particle size D ₅₀ of 4 μm. The particle size D ₅₀ is a volume center value (volume-based median diameter) obtained by a laser diffraction method using an air flow dispersion method.

Zinc stearate as a lubricant was added to the finely pulverized powder in an amount of 0.05 mass% with respect to 100 mass% of the finely pulverized powder, and the mixture was molded in a magnetic field to obtain a molded body. A so-called orthogonal magnetic field molding device (transverse magnetic field molding device) in which the magnetic field applying direction and the pressurizing direction are orthogonal to each other was used as the molding device.

The obtained compact was sintered in vacuum at 1040° C. or lower (selecting a temperature at which sufficient densification by sintering is selected) for 4 hours and then rapidly cooled to obtain a magnet material. The density of the obtained magnet material was 7.5 Mg/m 3 or more. Table 25 shows the results of the components of the obtained magnet material. In addition, each component in Table 25 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES). In addition, as a result of measuring the oxygen content of the magnet material by the gas melting-infrared absorption method, it was confirmed that all were about 0.1 mass %. Moreover, as a result of measuring C (carbon content) using a gas analyzer by a combustion-infrared absorption method, it was confirmed that it was around 0.1 mass %. In Table 25, “[T]/[B]” means the analytical value (mass %) of each element (here, Fe, Al, Si, and Mn) constituting T divided by the atomic weight of the element. It is the ratio (a/b) of the value obtained by summing these values (a) and the value obtained by dividing the B analysis value (mass %) by the atomic weight of B (b). The same applies to all the tables below. It should be noted that, even if each composition, oxygen content, and carbon content in Table 25 are summed up, it does not reach 100 mass %. This is because the analysis method differs depending on each component as described above. The same applies to the other tables.

[Step of preparing RL1-RH-M1 series alloy]
Each element is weighed and the raw materials thereof are melted so as to have the composition of the RL1-RH-M1 system alloy shown by the symbols 7-a1 to 7-n1 in Table 26, and the single roll ultra-quenching method (melt spinning method) is used. A ribbon or flake alloy was obtained by. The obtained alloy was pulverized in an argon atmosphere using a mortar, and then passed through a sieve having an opening of 300 μm to prepare an L1-RH-M1 alloy. Table 26 shows the composition of the obtained RL1-RH-M1 alloy. In addition, each component in Table 26 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[First diffusion step]
The RTB sintered magnet material of 7-A in Table 25 was cut and cut into a cube of 7.2 mm x 7.2 mm x 7.2 mm. Next, PVA as an adhesive was applied to the entire surface of the RTB sintered magnet material by an dipping method on the RTB sintered magnet material. The RL1-RH-M1 system alloy powder was made to adhere to the RTB system sintered magnet raw material which applied the adhesive agent. The RL1-RH-M1 alloy powder was spread in a processing container and attached to the entire surface of the R-T-B sintered magnet material coated with an adhesive. Next, using a vacuum heat treatment furnace, in the reduced pressure argon controlled to 200 Pa, at the temperature shown in the first diffusion step of Table 28, the RL-RH-M system alloy and the R-T-B system sintered magnet material. Was heated to carry out the diffusion process, and then cooled.

[Process of preparing RL2-M2 alloy]
Each element was weighed and their raw materials were melted so as to have the composition of the RL2-M2 series alloy shown by the symbol 7-a2 in Table 27, and ribbon or flake shape was formed by the single roll ultra-quenching method (melt spinning method). An alloy was obtained. The obtained alloy was pulverized in an argon atmosphere using a mortar and then passed through a sieve with a mesh opening of 300 μm to prepare an RL2-M2 alloy. Table 27 shows the composition of the obtained RL2-M2 alloy. Each component in Table 27 was measured using a high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[Second diffusion step]
PVA as an adhesive was applied to the entire surface of the sample after the first diffusion step again by the dipping method. Then, the RL2-M2 alloy powder was spread in a processing container and adhered to the entire surface of the sample coated with the adhesive. Next, the RL2-M2 system alloy and the R-T-B system sintered magnet material are heated at a temperature shown in the second diffusion step of Table 28 in reduced pressure argon controlled to 200 Pa using a vacuum heat treatment furnace. After carrying out the diffusion process, the sample was cooled. The entire surface of each sample after the heat treatment was cut using a surface grinder to obtain a cubic sample (RTB sintered magnet) of 7.0 mm × 7.0 mm × 7.0 mm. Obtained. In addition, the heating temperature of the RL1-RH-M1 system alloy and the RTB system sintered magnet material in the process of performing the first diffusion process, and the RL2-M2 system alloy and R in the process of performing the second diffusion process. The heating temperature of the -TB sintered magnet material was measured by attaching a thermocouple.

[sample test]
Br and HcJ of each sample of the obtained sample were measured by a BH tracer. Table 28 shows the measurement results. As shown in Table 28, sample No. It can be seen that high Br and high HcJ were obtained in all of the inventive examples 7-1 to 7-14.

According to the present disclosure, an RTB-based sintered magnet having a high residual magnetic flux density and a high coercive force can be manufactured. INDUSTRIAL APPLICABILITY The sintered magnet according to the present disclosure is suitable for various motors such as a motor mounted on a hybrid vehicle exposed to high temperatures, home electric appliances, and the like.

12... Main phase composed of R ₂ T ₁₄ B compound, 14... Grain boundary phase, 14a... Two-grain grain boundary phase, 14b... Grain boundary triple point

Claims (4)

A step of preparing an RTB-based sintered magnet material,
A step of preparing an RL1-RH-M1 alloy,
A step of preparing an RL2-M2 alloy,
At least a part of the RL1-RH-M1 system alloy is attached to at least a part of the surface of the R-T-B system sintered magnet material, and the temperature is 700°C or more and 1100°C or less in a vacuum or an inert gas atmosphere. A first diffusion step of heating at temperature,
At least a part of the RL2-M2 system alloy is adhered to at least a part of the surface of the R-T-B system sintered magnet material on which the first diffusion process is performed, and the temperature is set to 400 in a vacuum or an inert gas atmosphere. A second diffusion step of heating at a temperature of ℃ or more and 600 ℃ or less,
The amount of the RL1-RH-M1 alloy deposited on the R-T-B sintered magnet material in the first diffusion step is 4 mass% or more and 15 mass% or less, and depends on the RL1-RH-M1 alloy. The amount of RH attached to the R-T-B based sintered magnet material is 0.1 mass% or more and 0.6 mass% or less,
The amount of the RL2-M2 based alloy adhered to the RTB-based sintered magnet material subjected to the first diffusion step in the second diffusion step is 1 mass% or more and 15 mass% or less,
In the R-T-B system sintered magnet material,
R is a rare earth element and always contains at least one selected from the group consisting of Nd, Pr and Ce, and the content of R is 27 mass% or more and 35 mass% or less of the entire RTB-based sintered magnet material. And
T is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, T always contains Fe, and the content of Fe with respect to the entire T is 80 mass% or more,
The molar ratio of [T]/[B] is more than 14.0 and 15.0 or less,
In the RL1-RH-M1 series alloy,
RL1 is at least one of the light rare earth elements, and always contains at least one selected from the group consisting of Nd, Pr and Ce, and the content of RL1 is 60 mass% of the entire RL1-RH-M1 alloy. Is 97 mass% or less,
RH is at least one selected from the group consisting of Tb, Dy, and Ho, and the content of RH is 1 mass% or more and 8 mass% or less of the entire RL1-RH-M1 alloy,
M1 is at least one selected from the group consisting of Cu, Ga, Fe, Co, Ni, and Al, and the content of M1 is 2 mass% or more and 39 mass% or less of the entire RL1-RH-M1 alloy. Yes,
In the RL2-M2 alloy,
RL2 is at least one of the light rare earth elements, and always contains at least one selected from the group consisting of Nd, Pr and Ce, and the content of RL2 is 60 mass% or more and 97 mass% or more of the entire RL2-M2 alloy. % Or less,
M2 is at least one selected from the group consisting of Cu, Ga, Fe, Co, Ni, and Al, and the content of M2 is 3 mass% or more and 40 mass% or less of the entire RL2-M2 alloy. A method for manufacturing an RTB-based sintered magnet. In the RL1-RH-M1 system alloy, the content of RH is 2 mass% or more and 6 mass% or less of the entire RL1-RH-M1 system alloy, and the RTB system sintered magnet according to claim 1. Production method. The R- according to claim 1 or 2, wherein an amount of the RL1-RH-M1 based alloy deposited on the R-T-B based sintered magnet material in the first diffusion step is 5 mass% or more and 10 mass% or less. A manufacturing method of a TB type sintered magnet. The R according to any one of claims 1 to 3, wherein an amount of the RL2-M2 alloy deposited on the R-T-B sintered magnet material in the second diffusion step is 2 mass% or more and 10 mass% or less. -The manufacturing method of a TB type sintered magnet.

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