JPWO2019065481A1 - Method for producing RTB-based sintered magnet - Google Patents

Abstract

The manufacturing method of the RTB-based sintered magnet of the present disclosure includes a step of preparing an R1-T1-B-based sintered body, a step of preparing an R2-Ga-Cu-Co-based alloy, and the sintering. A step of bringing at least a part of the alloy into contact with at least a part of the surface of the body and performing a first heat treatment at a temperature of 700 ° C. or higher and 1100 ° C. or lower in a vacuum or an inert gas atmosphere; Performing a second heat treatment on the implemented R1-T1-B-based sintered body at a temperature of 450 ° C. or higher and 600 ° C. or lower in a vacuum or an inert gas atmosphere. R1 and R2 are at least one of rare earth elements, and always include at least one of Nd and Pr. The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0.

Description

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

  An R-T-B sintered magnet (R is at least one of rare earth elements. T is at least one of transition metal elements and must contain Fe. B is boron) is a permanent magnet. Known as the most powerful magnet, 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 appliances. Yes.

An R-T-B sintered magnet is mainly composed of a main phase composed of an R ₂ T ₁₄ B compound and a grain boundary phase (hereinafter sometimes simply referred to as “grain boundary”) located at the grain boundary portion of the main phase. It is configured. The R ₂ T ₁₄ B compound is a ferromagnetic phase with high magnetization, and forms the basis of the characteristics of the R-T-B system sintered magnet.

The _RTB -based sintered magnet has a problem that irreversible thermal demagnetization occurs because the coercive force H _cJ (hereinafter sometimes simply referred to as “coercive force” or “H _cJ ”) decreases at a high temperature. Therefore, an _RTB -based sintered magnet used particularly for an electric vehicle motor is _required to have a high H _cJ even at a high temperature, that is, a higher H _cJ at room temperature.

In the RTB-based sintered magnet, a part of the light rare earth element (mainly Nd and / or Pr) contained in R in the R ₂ T ₁₄ B compound is a heavy rare earth element (mainly Dy and / or Tb). Substitution is known to improve H _cJ . As the substitution amount of heavy rare earth elements increases, H _cJ improves.

However, when the light rare earth element in the R ₂ T ₁₄ B compound is replaced with a heavy rare earth element, the H _{cJ of the RTB} -based sintered magnet is improved, while the residual magnetic flux density B _r (hereinafter simply referred to as “B _r ”). May be reduced). In addition, heavy rare earth elements, particularly Dy, have a problem that their supply is not stable and the price fluctuates greatly because of their low resource abundance and limited production area. Therefore, in recent years, it has been demanded by _users to improve H _cJ without using heavy rare earth elements as much as possible.

Patent Document 1 discloses an RTB-based rare earth sintered magnet having an increased coercive force while reducing the Dy content. The composition of the sintered magnet is limited to a specific range in which the amount of B is relatively smaller than that of a generally used RTB-based alloy, and is selected from Al, Ga, and Cu. It contains more than seed metal element M. As a result, R ₂ T ₁₇ phase is produced in the grain boundary, by the volume ratio of the R ₂ T ₁₇ transition metal-rich phase formed in the grain boundary from phase (R ₆ T ₁₃ M) increases, H _cJ Will improve.

International Publication No. 2013/008756

The method described in Patent Document 1 is notable in that it can increase the coercive force of the RTB-based sintered magnet while suppressing the content of heavy rare earth elements. However, there is a problem that _Br is significantly reduced. In recent years, there has been a demand for _RTB -based sintered magnets having higher H _cJ for applications such as motors for electric vehicles.

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

  In an exemplary embodiment that is not limited, the method for manufacturing an R-T-B-based sintered magnet of the present disclosure includes a step of preparing an R1-T1-B-based sintered body, and an R2-Ga-Cu-Co A step of preparing an alloy, and at least a part of the R2-Ga-Cu-Co alloy is brought into contact with at least a part of the surface of the R1-T1-B sintered body, and a vacuum or an inert gas atmosphere In a vacuum or in an inert gas atmosphere, the first heat treatment is performed at a temperature of 700 ° C. or higher and 1100 ° C. or lower, and the R1-T1-B sintered body on which the first heat treatment is performed. And performing a second heat treatment at a temperature of 450 ° C. or higher and 600 ° C. or lower. In the R1-T1-B based sintered body, R1 is at least one of rare earth elements, and always includes at least one of Nd and Pr, and the content of R1 is the entire R1-T1-B based sintered body. 27 mass% or more and 35 mass% or less, T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, T1 always contains Fe, and the content of Fe relative to the entire T1 is 80 mass% or more, and the molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0. In the R2-Ga-Cu-Co-based alloy, R2 is at least one of rare earth elements, and always includes at least one of Nd and Pr, and the content of R2 is the total amount of the R2-Ga-Cu-Co-based alloy. 35 mass% or more and less than 85 mass%, the Ga content is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Cu-Co-based alloy, and the Cu content is R2-Ga-Cu-Co. The total alloy is 2.5 mass% or more and 20 mass% or less, and the Co content is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Cu-Co alloy, and the content of R2> the content of Co > Ga content> Cu content inequality holds.

  In one embodiment, the molar ratio of T to B ([T1] / [B]) is 14.5 or more and 15.0 or less.

  In one embodiment, 50 mass% or more of R2 in the R2-Ga-Cu-Co-based alloy is Pr.

  In one embodiment, 70 mass% or more of R2 in the R2-Ga-Cu-Co-based alloy is Pr.

  In one embodiment, the total content of R2-Ga-Cu-Co in the R2-Ga-Cu-Co-based alloy is 80 mass% or more.

  In one embodiment, the temperature in the first heat treatment is 800 ° C. or higher and 1000 ° C. or lower.

  In one embodiment, the temperature in the second heat treatment is 480 ° C. or higher and 560 ° C. or lower.

The step of preparing the R1-T1-B sintered body includes pulverizing the raw material alloy so that the particle diameter D ₅₀ is 3 μm or more and 10 μm or less, and then orienting it in a magnetic field to perform sintering.

  The manufacturing method of the RTB-based sintered magnet of the present disclosure includes, in another exemplary non-limiting embodiment, a step of preparing an R1-T1-Cu-B-based sintered body, and R2-Ga A step of preparing a Co alloy, and at least a part of the R2-Ga-Co alloy is brought into contact with at least a part of the surface of the R1-T1-Cu-B sintered body, and vacuum or inert In the gas atmosphere, the first heat treatment is performed at a temperature of 700 ° C. or higher and 1100 ° C. or lower, and the R1-T1-Cu—B based sintered body on which the first heat treatment is performed is vacuum or non-conductive. Performing a second heat treatment at a temperature of 450 ° C. or higher and 600 ° C. or lower in an active gas atmosphere. In the R1-T1-Cu—B based sintered body, R1 is at least one of rare earth elements. Yes, and must contain at least one of Nd and Pr, The content of 1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-Cu-B-based sintered body, and T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si. T1 always contains Fe, the Fe content with respect to the whole T1 is 80 mass% or more, and the molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0. And the Cu content is 0.1 mass% or more and 1.5 mass% or less of the entire R1-T1-Cu-B-based sintered body. In the R2-Ga-Co-based alloy, R2 is a rare earth element. At least one of Nd and Pr is necessarily included, the content of R2 is 35 mass% or more and less than 87 mass% of the entire R2-Ga-Co-based alloy, and the Ga content is R2-Ga It is 2.5 mass% or more and 30 mass% or less of the entire Co-based alloy, and the Co content is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Co-based alloy, and the content of R2> the content of Co> An inequality of Ga content holds.

  In one embodiment, the molar ratio of T1 to B ([T1] / [B]) is 14.3 or more and 15.0 or less.

  In one embodiment, 50 mass% or more of R2 in the R2-Ga-Co-based alloy is Pr.

  In one embodiment, Pr is 70 mass% or more of R2 in the R2-Ga-Co-based alloy.

  In one embodiment, the total content of R2, Ga, and Co in the R2-Ga-Co-based alloy is 80 mass% or more.

  In a certain embodiment, the temperature in said 1st heat processing is 800 degreeC or more and 1000 degrees C or less.

  In a certain embodiment, the temperature in said 2nd heat processing is 480 degreeC or more and 560 degrees C or less.

In one embodiment, in the step of preparing the R1-T1-Cu-B-based sintered body, the raw material alloy is pulverized to have a particle size D ₅₀ of 3 μm or more and 10 μm or less, and then oriented in a magnetic field for sintering. Including that.

According to embodiments of the present disclosure, while reducing the content 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 a high H _cJ.

It is a flowchart which shows the example of the process in the manufacturing method (1st Embodiment) of the RTB type | system | group sintered magnet by this indication. It is a schematic diagram which shows the main phase and grain boundary phase of a RTB system sintered magnet. It is the schematic diagram which expanded further the inside of the broken-line rectangular area of FIG. 2A. Arrangement of R1-T1-B-based alloy sintered body (or R1-T1-Cu-B-based sintered body) and R2-Ga-Cu-Co-based alloy (or R2-Ga-Co-based alloy) in the heat treatment step It is explanatory drawing which shows a form typically. It is a flowchart which shows the example of the process in the manufacturing method (2nd Embodiment) of the RTB type sintered magnet by this indication.

  In the present disclosure, rare earth elements are sometimes collectively referred to as “R”. When a specific element or a group of elements among the rare earth elements R is pointed out, for example, a symbol “R1” or “R2” is used to distinguish them from other rare earth elements. In the present disclosure, the entire transition metal element including Fe is denoted as “T”. When including both a specific element or group of elements of the transition metal element T and a specific element or group of elements other than the transition metal element easily replaced with the Fe site of the main phase, the symbol “T1” is used. Distinguish from other transition metal elements.

<First Embodiment>
As shown in FIG. 1, the manufacturing method of the RTB-based sintered magnet in the first embodiment according to the present disclosure includes the step S10 of preparing an R1-T1-B-based sintered body, and the R2-Ga- And a step S20 of preparing a Cu—Co alloy. The order of the step S10 for preparing the R1-T1-B-based sintered body and the step S20 for preparing the R2-Ga-Cu-Co-based alloy is arbitrary, and R1-T1- manufactured at different locations, respectively. B-based sintered bodies and R2-Ga-Cu-Co-based alloys may be used.

  In the present disclosure, the RTB-based sintered magnet before the second heat treatment and during the second heat treatment is referred to as an R1-T1-B-based sintered body, and the R1-T1-B system after the second heat treatment. The sintered body is simply referred to as an R-T-B system sintered magnet.

In the R1-T1-B based sintered body, the following (A1) to (A3) are established.
(A1) R1 is at least one of rare earth elements and always contains at least one of Nd and Pr, and the content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-B sintered body.
(A2) T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si. T1 always contains Fe, and the Fe content with respect to the entire T1 is 80 mass% or more.
(A3) The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0.

  In the present disclosure, the molar ratio of T1 to B ([T1] / [B]) is an analysis value (mass%) of each element (Fe or at least one of Fe, Co, Al, Mn, and Si) constituting T1. Obtained by dividing by the atomic weight of each element, and the ratio (a /) of the total of those values (a) and the analytical value of B (mass%) divided by the atomic weight of B (b) b).

The molar ratio of T1 to B ([T1] / [B]) exceeding 14.0 means that the B content ratio is lower than the stoichiometric composition ratio of the R ₂ T ₁₄ B compound. Yes. In other words, in the R1-T1-B-based sintered body, the B amount is relatively small with respect to the amount of T1 used for forming the main phase (R ₂ T ₁₄ B compound).

In the R2-Ga-Cu-Co-based alloy, the following (A4) to (A8) are established.
(A4) R2 is at least one of rare earth elements and always contains at least one of Nd and Pr, and the content of R2 is not less than 35 mass% and less than 85 mass% of the entire R2-Ga-Cu-Co-based alloy.
(A5) Ga content is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Cu-Co-based alloy.
(A6) The Cu content is 2.5 mass% or more and 20 mass% or less of the entire R2-Ga-Cu-Co-based alloy.
(A7) The Co content is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Cu-Co-based alloy.
(A8) The inequality of R2 content> Co content> Ga content> Cu content holds.

In the manufacturing method of the RTB-based sintered magnet according to the present disclosure, the amount of B is relatively small in stoichiometric ratio with respect to the amount of T used for forming the main phase (R ₂ T ₁₄ B compound). The R2-Ga-Cu-Co alloy is brought into contact with at least a part of the surface of the -T1-B sintered body, and as shown in FIG. 1, in a vacuum or an inert gas atmosphere, the temperature is 700 ° C. or higher and 1100 ° C. or lower. A temperature of 450 ° C. or more and 600 ° C. or less in a vacuum or an inert gas atmosphere with respect to the step S30 for performing the first heat treatment at a temperature and the R1-T1-B sintered body subjected to the first heat treatment. In step S40, the second heat treatment is performed. Thus, it is possible to obtain the R-T-B based sintered magnet having a high B _r and a high H _cJ.

  Another process, such as a cooling process, may be performed between the process S30 for performing the first heat treatment and the process S40 for performing the second heat treatment.

  First, the basic structure of the RTB-based sintered magnet will be described.

The RTB-based sintered magnet has a structure in which powder particles of raw material alloys are bonded by sintering, and a main phase mainly composed of an R ₂ T ₁₄ B compound and a grain boundary portion of the main phase. It consists of the grain boundary phase located.

FIG. 2A is a schematic diagram showing the main phase and the grain boundary phase of the RTB-based sintered magnet, and FIG. 2B is a schematic diagram further enlarging the broken-line rectangular region of FIG. 2A. In FIG. 2A, for example, an arrow having a length of 5 μm is described as a reference length indicating the size for reference. As shown in FIGS. 2A and 2B, 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 in a grain boundary portion of the main phase 12. It consists of and. As shown in FIG. 2B, the grain boundary phase 14 includes two grain boundary phases 14a in which two R ₂ T ₁₄ B compound particles (grains) are adjacent, and three or more R ₂ T ₁₄ B compound particles. Includes adjacent grain boundary triple points 14b.

The R ₂ T ₁₄ B compound as the main phase 12 is a ferromagnetic phase having a 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 amount, T amount, and B amount in the raw material alloy are set to the stoichiometric ratio of the R ₂ T ₁₄ B compound (R amount: T amount: B amount = It may be close to 2: 14: 1). When the B amount or R amount for forming the R ₂ T ₁₄ B compound is lower than the stoichiometric ratio, generally, a ferromagnetic material such as an Fe phase or an R ₂ T ₁₇ phase is generated in the grain boundary phase 14. , H _cJ decreases rapidly. However, as in the method described in Patent Document 1, the amount of B is less than the stoichiometric ratio of the R ₂ T ₁₄ B compound, and at least one selected from Al, Ga, and Cu is used. When the metal element M is contained, a transition metal rich phase (for example, R—T—Ga phase) is generated at the grain boundary from the R ₂ T ₁₇ phase, and high H _cJ can be obtained. However, in the method described in Patent Document 1, _Br is significantly reduced.

As a result of studies, the present inventors have found that at least a part of the surface of the R1-T1-B-based sintered body having a specific composition having a low B composition has a relatively high Co content of R2-Ga-Cu-. When contacting the Co-based alloy that perform particular heat treatment, surprisingly, finally sintered magnet obtained has been found to be achieved a high B _r and high H _cJ.

The manufacturing method of the RTB-based sintered magnet according to the present disclosure introduces R2, Ga, Cu, and Co into the inside from the magnet surface by the R2-Ga-Cu-Co-based alloy having a specific composition according to the present disclosure. High B _r and high H _cJ can be realized.

(Step of preparing R1-T1-B based sintered body)
First, the composition of the sintered body in the step of preparing an R1-T1-B-based sintered body (hereinafter sometimes simply referred to as “sintered body”) will be described.

R1 is at least one kind of rare earth elements and always contains at least one of Nd and Pr. In order to improve H _cJ of the R1-T1-B based sintered body, a small amount of generally used heavy rare earth elements such as Dy, Tb, Gd, and Ho may be contained. However, according to the production method according to the present disclosure, sufficiently high H _cJ can be obtained without using a large amount of heavy rare earth elements. Therefore, the content of the heavy rare earth element is preferably 1 mass% or less, more preferably 0.5 mass% or less, and not contained (substantially 0 mass%) of the R1-T1-B based sintered body. Is more preferable.

  Content of R1 is 27 mass% or more and 35 mass% or less of the whole R1-T1-B type sintered compact. When the content of R1 is less than 27 mass%, a liquid phase is not sufficiently generated in the sintering process, and it becomes difficult to sufficiently densify the R1-T1-B based sintered body. On the other hand, even if the content of R1 exceeds 35 mass%, the effect of the present disclosure can be obtained, but the alloy powder in the manufacturing process of the R1-T1-B based sintered body becomes very active. As a result, the alloy powder may be significantly oxidized or ignited, so 35 mass% or less is preferable. The content of R1 is more preferably 27.5 mass% or more and 33 mass% or less, and further preferably 28 mass% or more and 32 mass% or less.

T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, and T1 always contains Fe. That is, T1 may be Fe alone, or may be Fe and at least one of Co, Al, Mn, and Si. However, the content of Fe with respect to the entire T1 is 80 mass% or more. When the content of Fe is less than 80 mass%, B _r and H _cJ may be reduced. Here, “the content of Fe with respect to the entire T1 is 80 mass% or more” means, for example, when the content of T1 in the R1-T1-B sintered body is 70 mass%, the R1-T1-B based sintering. It means that 56 mass% or more of the body is Fe. Preferably, the Fe content relative to the entire T1 is 90 mass% or more. This is because it is possible to obtain a higher B _r and a high H _cJ. When Co, Al, Mn, and Si are contained, the preferable content is as follows: Co of the entire R1-T1-Cu-B-based sintered body is 5.0 mass% or less, Al is 1.5 mass% or less, and Mn and Si are Each is 0.2 mass% or less.

  The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0.

  In the present disclosure, the molar ratio of T1 to B ([T1] / [B]) is an analysis value (mass%) of each element (Fe or at least one of Fe, Co, Al, Mn, and Si) constituting T1. Obtained by dividing by the atomic weight of each element, and the ratio (a /) of the total of those values (a) and the analytical value of B (mass%) divided by the atomic weight of B (b) b).

The condition that the molar ratio of T1 to B ([T1] / [B]) exceeds 14.0 is that the amount of B is relative to the amount of T1 used to form the main phase (R ₂ T ₁₄ B compound). It shows that there are few. When the molar ratio of T1 to B ([T1] / [B]) is 14.0 or less, high H _cJ cannot be obtained. On the other hand, if the molar ratio of T1 to B ([T1] / [B]) exceeds 15.0, _Br may decrease. The molar ratio of T1 to B ([T1] / [B]) is preferably 14.5 or more and 15.0 or less. It is possible to obtain a higher B _r and a high H _cJ. The B content is preferably 0.9 mass% or more and less than 1.0 mass% of the entire R1-T1-B sintered body.

In addition to the above elements, the R1-T1-B based sintered body includes Ga, Cu, Ag, Zn, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Cr, H, F, P, S, Cl, O, N, C and the like may be contained. The contents of Ga, Cu, Ag, Zn, In, Sn, Zr, Nb, and Ti are each 0.5 mass% or less, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, and Cr are each preferably 0.2 mass% or less, H, F, P, S, and Cl are 500 ppm or less, O is 6000 ppm or less, N is 1000 ppm or less, and C is 1500 ppm or less. The total content of these elements is preferably 5 mass% or less of the entire R1-T1-B sintered body. The total content of these elements may not be able to obtain the high B _r and high H _cJ exceeds 5 mass% of the total R1-T1-B based sintered body.

Next, the process for preparing the R1-T1-B based sintered body will be described. The step of preparing the R1-T1-B based sintered body can be prepared using a general manufacturing method represented by an RTB-based sintered magnet. In the R1-T1-B based sintered body, the raw material alloy is pulverized to a particle size D ₅₀ (volume center value obtained by measurement by an air flow dispersion type laser diffraction method = D ₅₀ ) of 3 μm or more and 10 μm or less. It is preferable to perform orientation and sintering. For example, a raw material alloy produced by a strip casting method or the like is pulverized to a particle size D ₅₀ of 3 μm or more and 10 μm or less using a jet mill apparatus or the like, and then molded in a magnetic field, and 900 ° C. or more and 1100 ° C. or less. It can prepare by sintering at the temperature of. If the particle diameter D _{50 of the} raw material alloy is less than 3 μm, it is very difficult to produce a pulverized powder, which is not preferable because the production efficiency is greatly reduced. On the other hand, when the particle size D ₅₀ exceeds 10 μm, the crystal particle size of the finally obtained R1-T1-B sintered body becomes too large, and it is difficult to obtain high H _cJ, which is not preferable. The particle size D ₅₀ is preferably 3 μm or more and 5 μm or less.

  The R1-T1-B-based sintered body may be made from one type of raw material alloy (single raw material alloy) as long as each of the above conditions is satisfied, or two or more types of raw material alloys may be used. You may produce by the method (blending method) of mixing. In addition, the obtained R1-T1-B sintered body may be subjected to a first heat treatment and a second heat treatment, which will be described later, after performing known machining such as cutting and cutting as necessary. .

(Step of preparing an R2-Ga-Cu-Co-based alloy)
First, the composition of the R2-Ga-Cu-Co alloy in the step of preparing the R2-Ga-Cu-Co alloy will be described. By containing all of R, Ga, Cu, and Co in a specific range described below, R2, Ga, Cu, and R in the R2-Ga-Cu-Co-based alloy in the step of performing the first heat treatment described below. Co can be introduced into the R1-T1-B sintered body.

R2 is at least one kind of rare earth elements and always contains at least one of Nd and Pr. It is preferable that 50 mass% or more of R2 is Pr. This is because a higher H _cJ can be obtained. Here, "50 mass% or more of R2 is Pr" means that, for example, when the content of R2 in the R2-Ga-Cu-Co-based alloy is 50 mass%, 25 mass of the R2-Ga-Cu-Co-based alloy. % Or more means Pr. More preferably, 70 mass% or more of R2 is Pr, and most preferably R2 is Pr alone (including inevitable impurities). Thereby, higher H _cJ can be obtained. Further, as R2, a small amount of heavy rare earth elements such as Dy, Tb, Gd, and Ho may be contained. However, according to the production method of the present disclosure, sufficiently high H _cJ can be obtained without using a large amount of heavy rare earth elements. Therefore, the content of the heavy rare earth element is preferably 10 mass% or less of the entire R2-Ga-Cu-Co alloy (the heavy rare earth element in the R2-Ga-Cu-Co alloy is 10 mass% or less), It is more preferable that it is 5 mass% or less, and it is still more preferable not to contain (substantially 0 mass%). Even when R2 of the R2-Ga-Cu-Co-based alloy contains a heavy rare earth element, 50% or more of R2 is preferably Pr, and R2 excluding the heavy rare earth element is only Pr (inevitable impurities included) ) Is more preferable.

The content of R2 is 35 mass% or more and less than 85 mass% of the entire R2-Ga-Cu-Co-based alloy. If the content of R2 is less than 35 mass%, the diffusion may not sufficiently proceed in the first heat treatment described later. On the other hand, even if the content of R2 is 85 mass% or more, the effect of the present disclosure can be obtained, but the alloy powder in the manufacturing process of the R2-Ga-Cu-Co alloy becomes very active. As a result, since significant oxidation or ignition of the alloy powder may occur, the content of R2 is preferably less than 85 mass% of the entire R2-Ga-Cu-Co-based alloy. The content of R2 is more preferably 50 mass% or more and less than 85 mass%, and further preferably 60 mass% or more and less than 85 mass%. This is because a higher H _cJ can be obtained.

Ga is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Cu-Co-based alloy. If Ga is less than 2.5 mass%, it is difficult to introduce Co in the R2-Ga-Cu-Co-based alloy into the R1-T1-B-based sintered body in the step of performing the first heat treatment described later. _Br cannot be obtained. Furthermore, since the amount of R—T—Ga phase produced is too small, high H _cJ cannot be obtained. On the other hand, if Ga is more than 30 mass%, B _r may be lowered significantly. Ga is more preferably 4 mass% or more and 20 mass% or less, and further preferably 4 mass% or more and 10 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

Cu is 2.5 mass% or more and 20 mass% or less of the entire R2-Ga-Cu-Co-based alloy. If Cu is less than 2.5 mass%, Ga, Cu and Co in the R2-Ga-Cu-Co-based alloy are introduced into the R1-T1-B-based sintered body in the step of performing the first heat treatment described later. hardly be, it is impossible to obtain a high B _r. On the other hand, if Cu exceeds 20 mass%, the abundance ratio of Ga at the grain boundary is lowered, and thus the amount of R—T—Ga phase produced is so small that high H _cJ may not be obtained. Cu is more preferably 4 mass% or more and 15 mass% or less, and further preferably 4 mass% or more and 10 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

Co is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Cu-Co-based alloy. Co is in the following 10 mass%, it is impossible to sufficiently enhance the finally obtained R-T-B based sintered magnet of B _r. On the other hand, when Co exceeds 45Mass%, it may not be able to spread with a first heat treatment to be described later does not proceed sufficiently to obtain a high B _r and high H _cJ. Co is more preferably 15 mass% or more and 30 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

In the R2-Ga-Cu-Co-based alloy according to the present disclosure, the inequality of R2 content> Co content> Ga content> Cu content is established. Therefore, it is possible to obtain a high B _r and a high H _cJ. This is considered to be because a phase containing an appropriate amount of R, Co, Ga, and Cu is generated at the grain boundary by satisfying the inequality of the present disclosure.

  R2-Ga-Cu-Co-based alloys include Al, Ag, Zn, Si, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, in addition to the above elements. La, Ce, Sm, Ca, Mg, Mn, Cr, H, F, P, S, Cl, O, N, C and the like may be contained.

Content is 1.0 mass% or less for Al, Ag, Zn, Si, In, Sn, Zr, Nb, and Ti are each 0.5 mass% or less, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Si, Cr are each 0.2 mass% or less, H, F, P, S, and Cl are 500 ppm or less, O is 6000 ppm or less, N is 1000 ppm or less, and C is 1500 ppm or less is preferable. However, the total content of these elements is more than 20mass%, R2-Ga-Cu -Co -based then the amount of R2-Ga-Cu-Co in the alloy, to obtain a high B _r and high H _cJ It may not be possible. Therefore, the total content of R2-Ga-Cu-Co in the R2-Ga-Cu-Co-based alloy is preferably 80 mass% or more, and more preferably 90 mass% or more.

  Next, the process for preparing the R2-Ga-Cu-Co alloy will be described. The R2-Ga-Cu-Co-based alloy is a raw material alloy manufacturing method employed in a general manufacturing method represented by an Nd-Fe-B-based sintered magnet, such as a die casting method or a strip casting method. Or a single roll super rapid cooling method (melt spinning method) or an atomizing method. The R2-Ga-Cu-Co-based alloy may be one obtained by pulverizing the alloy obtained as described above by a known pulverizing means such as a pin mill. Further, in order to improve the pulverizability of the alloy obtained as described above, the pulverization may be performed after heat treatment at 700 ° C. or less in a hydrogen atmosphere to contain hydrogen.

(Step of performing the first heat treatment)
At least a part of the R2-Ga-Cu-Co-based alloy is brought into contact with at least a part of the surface of the R1-T1-B-based sintered body prepared as described above, and is 700 ° C or higher in a vacuum or an inert gas atmosphere. Heat treatment is performed at a temperature of 1100 ° C. or lower. In the present disclosure, this heat treatment is referred to as a first heat treatment. Thereby, a liquid phase containing Cu, Ga, and Co is generated from the R2-Ga-Cu-Co-based alloy, and the liquid phase passes through the grain boundary of the R1-T1-B-based sintered body, and the surface of the sintered body. Is introduced into the interior. When the first heat treatment temperature is lower than 700 ° C., Cu, and amount of liquid phase containing Ga and Co is too small, it may not be able to obtain a high B _r and high H _cJ. On the other hand, when the temperature exceeds 1100 ° C., abnormal grain growth of the main phase occurs and H _cJ may decrease. The first heat treatment temperature is preferably 800 ° C. or higher and 1000 ° C. or lower. This is because it is possible to obtain a higher B _r and a high H _cJ. In addition, although heat processing time sets an appropriate value with the composition, dimension, heat processing temperature, etc. of a R1-T1-B type sintered compact or a R2-Ga-Cu-Co type alloy, 5 minutes or more and 20 hours or less are preferred, and 10 It is more preferably from 15 minutes to 15 hours, and further preferably from 30 minutes to 10 hours. Further, it is preferable that the R2-Ga-Cu-Co-based alloy is prepared in a range of 2 mass% to 30 mass% with respect to the weight of the R1-T1-B-based sintered body. If the R2-Ga-Cu-Co-based alloy is less than 2 mass% with respect to the weight of the R1-T1-B-based sintered body, _HcJ may be lowered. On the other hand, there is a possibility that the B _r decreases exceeds 30 mass%.

  The first heat treatment can be performed using a known heat treatment apparatus by disposing an R2-Ga-Cu-Co alloy having an arbitrary shape on the surface of the R1-T1-B sintered body. For example, the surface of the R1-T1-B-based sintered body can be covered with a powder layer of R2-Ga-Cu-Co-based alloy, and the first heat treatment can be performed. For example, after applying a slurry in which an R2-Ga-Cu-Co-based alloy is dispersed in a dispersion medium to the surface of the R1-T1-B-based sintered body, the dispersion medium is evaporated to obtain an R2-Ga-Cu-Co-based The alloy and the R1-T1-B sintered body may be brought into contact with each other. Further, as shown in an experimental example to be described later, the R2-Ga-Cu-Co-based alloy may be arranged so as to be in contact with at least a surface perpendicular to the orientation direction of the R1-T1-B-based sintered body. preferable. In addition, alcohol (ethanol etc.), NMP (N-methylpyrrolidone), an aldehyde, and a ketone can be illustrated as a dispersion medium. Moreover, you may perform well-known machining, such as a cutting | disconnection and cutting, with respect to the R1-T1-B type sintered compact in which the 1st heat processing was implemented.

(Step of performing the second heat treatment)
The R1-T1-B sintered body subjected to the first heat treatment is heat-treated at a temperature of 450 ° C. or higher and 600 ° C. or lower in a vacuum or an inert gas atmosphere. In the present disclosure, this heat treatment is referred to as a second heat treatment. By performing the second heat treatment, it is possible to obtain a high B _r and high H _cJ. When the temperature of the second heat treatment is less than 450 ° C. and more than 600 ° C., the amount of R—T—Ga phase (typically, R ₆ T ₁₃ Z phase (Z is at least one of Cu and Ga)) is too small, it may not be able to obtain a high B _r and high H _cJ. The second heat treatment temperature is preferably 480 ° C. or higher and 560 ° C. or lower. Higher H _cJ can be obtained. The heat treatment time is set to an appropriate value depending on the composition and dimensions of the R1-T1-B-based sintered body, the heat treatment temperature, etc., preferably 5 minutes to 20 hours, more preferably 10 minutes to 15 hours, more preferably 30 More preferably, it is 10 minutes or more.

In the above R ₆ T ₁₃ Z phase (R ₆ T ₁₃ Z compound), R is at least one of rare earth elements and always contains at least one of Pr and Nd, and T is at least one of transition metal elements. Yes Fe is always included. The R ₆ T ₁₃ Z compound is typically an Nd ₆ Fe ₁₃ Ga compound. The R ₆ T ₁₃ Z compound has a La ₆ Co ₁₁ Ga ₃ type crystal structure. The R ₆ T ₁₃ Z compound may be an R ₆ T _13- δZ 1 ₊ δ compound depending on the state. Incidentally, the relatively large in R-T-B based sintered magnet Cu, if the Al and Si are _{contained, R 6 T 13- δ (Ga} 1-abc Cu a Al b Si c) to ₁₊ [delta] It may be.

  The RTB-based sintered magnet obtained by the step of performing the second heat treatment is a known surface treatment such as known machining such as cutting or cutting, or plating for imparting corrosion resistance. It can be performed. In addition, the RTB-based sintered magnet obtained by the manufacturing method of the present disclosure includes at least one of Fe, Co, Al, Mn, and Si in the RTB-based sintered magnet and T2 ( (Corresponding to T1 in the R1-T1-B based sintered body), the molar ratio of T2 to B ([T2] / [B]) is more than 14.0, and R, Fe, B, Cu, Ga Contains. In addition to R, Fe, B, Cu and Ga, Co, Al, Ag, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Si, Cr, H, F, P, S, Cl, O, N, C and the like may be contained.

<Second Embodiment>
Next, the manufacturing method of the RTB type | system | group sintered magnet in 2nd Embodiment by this indication is demonstrated.

  As shown in FIG. 4, the manufacturing method of the RTB-based sintered magnet in the second embodiment according to the present disclosure includes a step S110 of preparing an R1-T1-Cu-B-based sintered body, and R2- Step S120 for preparing a Ga—Co alloy. The order of the step S110 for preparing the R1-T1-Cu-B-based sintered body and the step S120 for preparing the R2-Ga-Co-based alloy is arbitrary, and R1-T1- manufactured at different locations, respectively. A Cu-B based sintered body and an R2-Ga-Co based alloy may be used.

In the R1-T1-Cu-B based sintered body, the following (B1) to (B4) are established.
(B1) R1 is at least one of rare earth elements, and necessarily contains at least one of Nd and Pr, and the content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-Cu-B sintered body. .
(B2) T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si. T1 always contains Fe, and the content of Fe with respect to the entire T1 is 80 mass% or more.
(B3) The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0.
(B4) The content of Cu is not less than 0.1 mass% and not more than 1.5 mass% of the entire R1-T1-Cu-B sintered body.

  In the present disclosure, the molar ratio of T1 to B ([T1] / [B]) is an analysis value (mass%) of each element (Fe or at least one of Fe, Co, Al, Mn, and Si) constituting T1. Obtained by dividing by the atomic weight of each element, and the ratio (a /) of the total of those values (a) and the analytical value of B (mass%) divided by the atomic weight of B (b) b).

The molar ratio of T1 to B ([T1] / [B]) exceeding 14.0 means that the B content ratio is lower than the stoichiometric composition ratio of the R ₂ T ₁₄ B compound. Yes. In other words, in the R1-T1-Cu-B based sintered body, the amount of B is relatively small with respect to the amount of T1 used for forming the main phase (R ₂ T ₁₄ B compound).

The following (B5) to (B8) are established in the R2-Ga-Co alloy.
(B5) R2 is at least one of rare earth elements and always contains at least one of Nd and Pr, and the content of R2 is 35 mass% or more and less than 87 mass% of the entire R2-Ga-Co-based alloy.
(B6) The Ga content is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Co-based alloy.
(B7) The Co content is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Co-based alloy.
(B8) The inequality of R2 content> Co content> Ga content is established.

In the manufacturing method of the RTB-based sintered magnet (second embodiment) according to the present disclosure, the stoichiometric ratio is relative to the amount of T used for forming the main phase (R ₂ T ₁₄ B compound). The R2-Ga-Co alloy is brought into contact with at least a part of the surface of the R1-T1-Cu-B sintered body having a small amount of B, and as shown in FIG. 4, in a vacuum or an inert gas atmosphere, In step S130 of performing the first heat treatment at a temperature of 700 ° C. or higher and 1100 ° C. or lower and the R1-T1-Cu—B sintered body subjected to the first heat treatment in a vacuum or an inert gas atmosphere Step S140 for performing the second heat treatment at a temperature of 450 ° C. or higher and 600 ° C. or lower is performed. Thus, it is possible to obtain the R-T-B based sintered magnet having a high B _r and a high H _cJ.

  Another process such as a cooling process may be performed between the process S130 for performing the first heat treatment and the process S140 for performing the second heat treatment.

As a result of investigation, the present inventors have determined that R2-Ga-Co having a relatively high Co content is present on at least a part of the surface of the R1-T1-Cu-B-based sintered body having a specific composition that is a low B composition. even if after specific heat treatment by contacting the system alloy, finally sintered magnet obtained has been found to be achieved a high B _r and high H _cJ.

The manufacturing method (2nd Embodiment) of the RTB type | system | group sintered magnet by this indication introduce | transduces R2, Ga, Co into the inside from the magnet surface with the R2-Ga-Co type alloy of the specific composition of this indication. by, it is possible to realize a high B _r and high H _cJ.

(Process for preparing R1-T1-Cu-B based sintered body)
First, the composition of the sintered body in the step of preparing the R1-T1-Cu-B based sintered body will be described.

R1 is at least one kind of rare earth elements and always contains at least one of Nd and Pr. In order to improve _HcJ of the R1-T1-Cu-B based sintered body, a small amount of generally used heavy rare earth elements such as Dy, Tb, Gd, and Ho may be contained. However, according to the production method according to the present disclosure, sufficiently high H _cJ can be obtained without using a large amount of heavy rare earth elements. Therefore, the content of the heavy rare earth element is preferably 1 mass% or less, more preferably 0.5 mass% or less of the R1-T1-Cu-B-based sintered body, and it does not contain (substantially) 0 mass%) is more preferable.

  Content of R1 is 27 mass% or more and 35 mass% or less of the whole R1-T1-Cu-B type sintered compact. If the content of R1 is less than 27 mass%, a liquid phase is not sufficiently generated in the sintering process, and it becomes difficult to sufficiently densify the R1-T1-Cu-B based sintered body. On the other hand, even if the content of R1 exceeds 35 mass%, the effect of the present disclosure can be obtained, but the alloy powder in the manufacturing process of the R1-T1-Cu-B based sintered body becomes very active. As a result, significant oxidation or ignition of the alloy powder may occur, so 35 mass% or less is preferable. The content of R1 is more preferably 27.5 mass% or more and 33 mass% or less, and further preferably 28 mass% or more and 32 mass% or less.

T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, and T1 always contains Fe. That is, T1 may be Fe alone, or may be Fe and at least one of Co, Al, Mn, and Si. However, the content of Fe with respect to the entire T1 is 80 mass% or more. When the content of Fe is less than 80 mass%, B _r and H _cJ may be reduced. Here, “the Fe content with respect to the entire T1 is 80 mass% or more” means that, for example, when the T1 content in the R1-T1-Cu—B-based sintered body is 70 mass%, the R1-T1-Cu— It means that 56 mass% or more of the B-based sintered body is Fe. Preferably, the Fe content relative to the entire T1 is 90 mass% or more. This is because it is possible to obtain a higher B _r and a high H _cJ. When Co, Al, Mn, and Si are contained, the preferable content is as follows: Co of the entire R1-T1-Cu-B-based sintered body is 5.0 mass% or less, Al is 1.5 mass% or less, and Mn and Si are Each is 0.2 mass% or less.

  The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0.

  In the present disclosure, the molar ratio of T1 to B ([T1] / [B]) is the analysis of each element (Fe or at least one of Co, Al, Mn, Si and Fe) as described above. A value obtained by dividing the value (mass%) by the atomic weight of each element, a sum of those values (a), and an analysis value of B (mass%) divided by the atomic weight of B (b) Ratio (a / b).

The condition that the molar ratio of T1 to B ([T1] / [B]) exceeds 14.0 is that the amount of B is relative to the amount of T1 used to form the main phase (R ₂ T ₁₄ B compound). It shows that there are few. When [T1] / [B] is 14.0 or less, high H _cJ cannot be obtained. On the other hand, there is a possibility to lower the B _r exceeds the 15.0 [T1] / [B] . [T1] / [B] is preferably 14.3 to 15.0. It is possible to obtain a higher B _r and a high H _cJ. Further, the content of B is preferably 0.9 mass% or more and less than 1.0 mass% of the entire R1-T1-Cu-B-based sintered body.

Content of Cu is 0.1 mass% or more and 1.5 mass% or less of the whole R1-T1-Cu-B type sintered compact. If Cu is less than 0.1 mass%, diffusion does not proceed sufficiently in the first heat treatment described later, and high H _cJ may not be obtained. On the other hand, Cu is the exceeding 1.5 mass% B _r may be reduced.

Also in this embodiment, the R1-T1-Cu-B-based sintered body includes Ga, Ag, Zn, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, in addition to the above elements. Mo, V, Y, La, Ce, Sm, Ca, Mg, Cr, H, F, P, S, Cl, O, N, C and the like may be contained. The contents of Ga, Ag, Zn, In, Sn, Zr, Nb, and Ti are 0.5 mass% or less, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, and Cr are each preferably 0.2 mass% or less, H, F, P, S, and Cl are 500 ppm or less, O is 6000 ppm or less, N is 1000 ppm or less, and C is preferably 1500 ppm or less. The total content of these elements is preferably 5 mass% or less of the entire R1-T1-Cu-B-based sintered body. The total content of these elements may not be able to obtain more than the high B _r and high H _cJ of 5 mass% of the total R1-T1-Cu-B-based sintered body.

Next, the process for preparing the R1-T1-Cu-B based sintered body will be described. The step of preparing the R1-T1-Cu-B-based sintered body can be prepared using a general manufacturing method represented by an RTB-based sintered magnet. In the R1-T1-Cu-B sintered body, the raw material alloy is pulverized so that the particle size D ₅₀ (volume center value obtained by measurement by an air flow dispersion type laser diffraction method = D ₅₀ ) is 3 μm or more and 10 μm or less. It is preferable to sinter by orientation. For example, a raw material alloy produced by a strip casting method or the like is pulverized to a particle size D ₅₀ of 3 μm or more and 10 μm or less using a jet mill apparatus or the like, and then molded in a magnetic field, and 900 ° C. or more and 1100 ° C. or less. It can prepare by sintering at the temperature of. If the particle diameter D _{50 of the} raw material alloy is less than 3 μm, it is very difficult to produce a pulverized powder, which is not preferable because the production efficiency is greatly reduced. On the other hand, when the particle size D ₅₀ exceeds 10 μm, the crystal particle size of the finally obtained R1-T1-Cu—B-based sintered body becomes too large, and it becomes difficult to obtain high H _cJ, which is not preferable. The particle size D ₅₀ is preferably 3 μm or more and 5 μm or less.

  The R1-T1-Cu-B-based sintered body may be produced from one type of raw material alloy (single raw material alloy) or two or more types of raw material alloys as long as the above-described conditions are satisfied. Alternatively, it may be produced by a method of mixing them (blending method). In addition, the obtained R1-T1-Cu-B-based sintered body is subjected to a first heat treatment and a second heat treatment, which will be described later, after performing known machining such as cutting and cutting as necessary. Also good.

(Step of preparing an R2-Ga-Co alloy)
First, the composition of the R2-Ga-Co alloy in the step of preparing the R2-Ga-Co alloy will be described. By containing all of R, Ga, and Co in a specific range described below, R2, Ga, and Co in the R2-Ga-Co-based alloy are R1-T1- It can introduce | transduce in a Cu-B type sintered compact.

R2 is at least one kind of rare earth elements and always contains at least one of Nd and Pr. It is preferable that 50 mass% or more of R2 is Pr. This is because a higher H _cJ can be obtained. Here, "50 mass% or more of R2 is Pr" means that, for example, when the content of R2 in the R2-Ga-Co alloy is 50 mass%, 25 mass% or more of the R2-Ga-Co alloy is Pr. Say that. More preferably, 70 mass% or more of R2 is Pr, and most preferably R2 is Pr alone (including inevitable impurities). Thereby, higher H _cJ can be obtained. Further, as R2, a small amount of heavy rare earth elements such as Dy, Tb, Gd, and Ho may be contained. However, according to the production method of the present disclosure, sufficiently high H _cJ can be obtained without using a large amount of heavy rare earth elements. Therefore, the content of the heavy rare earth element is preferably 10 mass% or less of the entire R2-Ga-Co alloy (the heavy rare earth element in the R2-Ga-Co alloy is preferably 10 mass% or less), and is preferably 5 mass% or less. More preferably, it is not contained (substantially 0 mass%). Even when R2 of the R2-Ga-Co-based alloy contains a heavy rare earth element, 50% or more of R2 is preferably Pr, and R2 excluding the heavy rare earth element is only Pr (including inevitable impurities). More preferably.

Content of R2 is 35 mass% or more and less than 87 mass% of the whole R2-Ga-Co-based alloy. If the content of R2 is less than 35 mass%, the diffusion may not sufficiently proceed in the first heat treatment described later. On the other hand, even if the content of R2 is 87 mass% or more, the effect of the present disclosure can be obtained, but the alloy powder in the manufacturing process of the R2-Ga-Co alloy becomes very active. As a result, since significant oxidation or ignition of the alloy powder may occur, the R2 content is preferably less than 85 mass% of the entire R2-Ga-Co-based alloy. The content of R2 is more preferably 50 mass% or more and less than 85 mass%, and further preferably 60 mass% or more and less than 85 mass%. This is because a higher H _cJ can be obtained.

Ga is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Co-based alloy. If Ga is less than 2.5 mass%, it is difficult to introduce Co in the R2-Ga-Co-based alloy into the R1-T1-Cu-B-based sintered body in the step of performing the first heat treatment described later. _Br cannot be obtained. Furthermore, since the amount of R—T—Ga phase produced is too small, high H _cJ cannot be obtained. On the other hand, if Ga is more than 30 mass%, B _r may be lowered significantly. Ga is more preferably 4 mass% or more and 20 mass% or less, and further preferably 4 mass% or more and 10 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

Co is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Co-based alloy. Co is in the following 10 mass%, it is impossible to sufficiently enhance the finally obtained R-T-B based sintered magnet of B _r. On the other hand, when Co exceeds 45Mass%, it may not be able to spread with a first heat treatment to be described later does not proceed sufficiently to obtain a high B _r and high H _cJ. Co is more preferably 15 mass% or more and 30 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

In the R2-Ga-Cu-Co-based alloy in the present disclosure, the inequality of R2 content> Co content> Ga content is established. Therefore, it is possible to obtain a high B _r and a high H _cJ. This is considered to be because a phase containing an appropriate amount of R, Co, and Ga is generated at the grain boundary by satisfying the inequality of the present disclosure.

  In addition to the above elements, R2-Ga-Co-based alloys include Cu, Al, Ag, Zn, Si, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Cr, H, F, P, S, Cl, O, N, C and the like may be contained.

The content of Cu and Al is 1.0 mass% or less, Ag, Zn, Si, In, Sn, Zr, Nb, and Ti are 0.5 mass% or less, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Si, and Cr are each 0.2 mass% or less, H, F, P, S, and Cl are 500 ppm or less, O is 6000 ppm or less, and N is 1000 ppm or less. C is preferably 1500 ppm or less. However, when the total content of these elements exceeds 20mass%, R2-Ga-Co-based R2 in the alloy, Ga, then the amount of Co, can not be obtained a high B _r and high H _cJ There is sex. Therefore, the total content of R2, Ga, and Co in the R2-Ga-Co alloy is preferably 80 mass% or more, and more preferably 90 mass% or more.

  Next, the process for preparing the R2-Ga-Co alloy will be described. The R2-Ga-Co-based alloy is a raw material alloy manufacturing method employed in a general manufacturing method typified by an Nd-Fe-B-based sintered magnet, such as a die casting method, a strip casting method, or a simple method. It can be prepared using a roll rapid quenching method (melt spinning method) or an atomizing method. The R2-Ga-Co-based alloy may be one obtained by pulverizing the alloy obtained as described above by a known pulverizing means such as a pin mill. Further, in order to improve the pulverizability of the alloy obtained as described above, the pulverization may be performed after heat treatment at 700 ° C. or less in a hydrogen atmosphere to contain hydrogen.

(Step of performing the first heat treatment)
At least a part of the R2-Ga-Co-based alloy is brought into contact with at least a part of the surface of the R1-T1-Cu-B-based sintered body prepared as described above, and is 700 ° C or higher in a vacuum or an inert gas atmosphere. Heat treatment is performed at a temperature of 1100 ° C. or lower. In the present disclosure, this heat treatment is referred to as a first heat treatment. Thereby, a liquid phase containing Ga and Co is generated from the R2-Ga-Co-based alloy, and the liquid phase passes through the grain boundary of the R1-T1-Cu-B-based sintered body from the surface of the sintered body. Introduced into the diffusion. When the first heat treatment temperature is lower than 700 ° C., and too small amount of liquid phase containing Ga and Co, there is a possibility that it is impossible to obtain a high B _r and high H _cJ. On the other hand, when the temperature exceeds 1100 ° C., abnormal grain growth of the main phase occurs and H _cJ may decrease. The first heat treatment temperature is preferably 800 ° C. or higher and 1000 ° C. or lower. This is because it is possible to obtain a higher B _r and a high H _cJ. In addition, although heat processing time sets an appropriate value with the composition, dimension, heat processing temperature, etc. of a R1-T1-Cu-B type sintered compact or a R2-Ga-Co type alloy, 5 minutes or more and 20 hours or less are preferable, and 10 It is more preferably from 15 minutes to 15 hours, and further preferably from 30 minutes to 10 hours. Further, it is preferable that the R2-Ga-Co-based alloy is prepared in a range of 2 mass% to 30 mass% with respect to the weight of the R1-T1-Cu-B-based sintered body. If the R2-Ga-Co-based alloy is less than 2 mass% with respect to the weight of the R1-T1-Cu-B-based sintered body, _HcJ may be lowered. On the other hand, there is a possibility that the B _r decreases exceeds 30 mass%.

  The first heat treatment can be performed using a known heat treatment apparatus by disposing an R2-Ga-Co alloy having an arbitrary shape on the surface of the R1-T1-Cu-B-based sintered body. For example, the surface of the R1-T1-Cu-B-based sintered body can be covered with a powder layer of R2-Ga-Co-based alloy, and the first heat treatment can be performed. For example, after applying a slurry in which an R2-Ga-Co-based alloy is dispersed in a dispersion medium to the surface of the R1-T1-Cu-B-based sintered body, the dispersion medium is evaporated to obtain an R2-Ga-Co-based alloy The R1-T1-Cu-B sintered body may be contacted. Further, as shown in an experimental example to be described later, the R2-Ga-Co-based alloy may be disposed so as to be in contact with at least a surface perpendicular to the orientation direction of the R1-T1-Cu-B-based sintered body. preferable. In addition, alcohol (ethanol etc.), NMP (N-methylpyrrolidone), an aldehyde, and a ketone can be illustrated as a dispersion medium. Moreover, you may perform well-known machining, such as a cutting | disconnection and cutting, with respect to the R1-T1-Cu-B type sintered compact in which the 1st heat processing was implemented.

(Step of performing the second heat treatment)
The R1-T1-Cu-B sintered body subjected to the first heat treatment is heat-treated at a temperature of 450 ° C. or higher and 600 ° C. or lower in a vacuum or an inert gas atmosphere. In the present disclosure, this heat treatment is referred to as a second heat treatment. By performing the second heat treatment, it is possible to obtain a high B _r and high H _cJ. When the temperature of the second heat treatment is less than 450 ° C. and more than 600 ° C., the amount of R—T—Ga phase (typically, R ₆ T ₁₃ Z phase (Z is at least one of Cu and Ga)) is too small, it may not be able to obtain a high B _r and high H _cJ. The second heat treatment temperature is preferably 480 ° C. or higher and 560 ° C. or lower. Higher H _cJ can be obtained. The heat treatment time is set to an appropriate value depending on the composition and dimensions of the R1-T1-Cu-B-based sintered body, the heat treatment temperature, etc., preferably 5 minutes to 20 hours, more preferably 10 minutes to 15 hours. More preferably, it is 30 minutes or more and 10 hours or less.

In the above R ₆ T ₁₃ Z phase (R ₆ T ₁₃ Z compound), R is at least one of rare earth elements and always contains at least one of Pr and Nd, and T is at least one of transition metal elements. Yes Fe is always included. The R ₆ T ₁₃ Z compound is typically an Nd ₆ Fe ₁₃ Ga compound. The R ₆ T ₁₃ Z compound has a La ₆ Co ₁₁ Ga ₃ type crystal structure. The R ₆ T ₁₃ Z compound may be an R ₆ T _13- δZ 1 ₊ δ compound depending on the state. Incidentally, the relatively large in R-T-B based sintered magnet Cu, if the Al and Si are _{contained, R 6 T 13- δ (Ga} 1-abc Cu a Al b Si c) to ₁₊ [delta] It may be.

  The RTB-based sintered magnet obtained by the step of performing the second heat treatment is a known surface treatment such as known machining such as cutting or cutting, or plating for imparting corrosion resistance. It can be performed. In addition, the RTB-based sintered magnet obtained by the manufacturing method of the present disclosure includes at least one of Fe, Co, Al, Mn, and Si in the RTB-based sintered magnet and T2 ( R1-T1-Cu-B based sintered body), the molar ratio of T2 to B ([T2] / [B]) is more than 14.0, and R, Fe, B, Cu , Ga is contained. In addition to R, Fe, B, Cu and Ga, Co, Al, Ag, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Si, Cr, H, F, P, S, Cl, O, N, C and the like may be contained.

<Example of the first embodiment>
The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Experimental example 1
[Step of preparing R1-T1-B based sintered body]
Each element is weighed so that the R1-T1-B sintered body becomes approximately 1-A in Table 1, and cast by a strip cast method to obtain a flaky raw material alloy having a thickness of 0.2 to 0.4 mm. It was. The obtained flaky raw material alloy was pulverized with hydrogen, heated to 550 ° C. in a vacuum and then cooled to obtain a coarsely pulverized powder. Next, after adding and mixing 0.04 mass% of zinc stearate as a lubricant with respect to 100 mass% of the coarsely pulverized powder, the resulting coarsely pulverized powder is mixed with nitrogen using an airflow pulverizer (jet mill device). Dry pulverization was performed in an air stream to obtain finely pulverized powder (alloy powder) having a particle diameter D50 of 4 μm. The particle diameter D ₅₀ is a volume center value (volume reference median diameter) obtained by a laser diffraction method using an airflow dispersion method.

  To the finely pulverized powder, zinc stearate as a lubricant was added and mixed in an amount of 0.05 mass% with respect to 100 mass% of the finely pulverized powder, and then molded in a magnetic field to obtain a molded body. In addition, what was called a perpendicular magnetic field shaping | molding apparatus (transverse magnetic field shaping | molding apparatus) with which the magnetic field application direction and the pressurization direction orthogonally crossed was used for the shaping | molding apparatus.

The obtained molded body was sintered in vacuum at 1030 ° C. (selecting a temperature at which densification by sintering was sufficiently selected) for 4 hours and then rapidly cooled to obtain an R1-T1-B sintered body. The density of the obtained sintered body was 7.5 Mg / m ³ or more. The results of the components of the obtained sintered body are shown in Table 1. Each component in Table 1 was measured using high frequency inductively coupled plasma optical emission spectrometry (ICP-OES). In addition, as a result of measuring the oxygen content of the sintered body by the gas melting-infrared absorption method, it was confirmed that all were around 0.2 mass%. Further, C (carbon content) was measured using a gas analyzer based on a combustion-infrared absorption method, and as a result, it was confirmed that it was around 0.1 mass%. “[T1] / [B]” in Table 1 is obtained by dividing the analysis value (mass%) by the atomic weight of each element for each element (here Fe, Al, Si, Mn) constituting T1. Is the ratio (a / b) between the sum of these values (a) and the B analysis value (mass%) divided by the atomic weight of B (b). The same applies to all the tables below. In addition, even if each composition of Table 1, oxygen amount, and carbon amount are totaled, 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 R2-Ga-Cu-Co-based alloy]
Each element is weighed so that the R2-Ga-Cu-Co-based alloy has a composition of reference numerals 1-a to 1-g in Table 2, and those raw materials are dissolved, and a single-roll ultra-rapid cooling method (melt spinning method) ) To obtain a ribbon or flaky alloy. The obtained alloy was pulverized in an argon atmosphere using a mortar and then passed through a sieve having an opening of 425 μm to prepare an R 2 -Ga—Cu—Co alloy. Table 2 shows the composition of the obtained R2-Ga-Cu-Co-based alloy. In addition, each component in Table 2 was measured using high frequency inductively coupled plasma optical emission spectrometry (ICP-OES).

[Step of performing first heat treatment]
The R1-T1-B sintered body indicated by reference numeral 1-A in Table 1 was cut and machined, and a rectangular parallelepiped of 4.4 mm × 10.0 mm × 11.0 mm (the 10.0 mm × 11.0 mm plane is the orientation direction) Vertical plane). Next, as shown in FIG. 3, in the processing container 3 made of niobium foil, a surface perpendicular to the orientation direction (arrow direction in the figure) of the R1-T1-B based sintered body 1 is mainly R2-. In order to come into contact with the Ga—Cu—Co alloy 2, R2-Ga—Cu—Co alloys 1-a to 1-g shown in Table 2 are converted into R1-T1-B alloys 1-A. A total of 20 mass% was arranged at 10 mass% with respect to the weight of the R1-T1-B sintered body above and below the bonded body. Next, the R2-Ga-Cu-Co-based alloy and the R1-T1-B-based firing were performed in a reduced pressure argon controlled to 200 Pa using a tubular air furnace at the temperature and time shown in the first heat treatment of Table 3. The bonded body was heated and subjected to the first heat treatment, and then cooled.

[Step of performing second heat treatment]
R1-T1-B system in which the first heat treatment was carried out at a temperature and time shown in the second heat treatment of Table 3 in reduced pressure argon controlled to 200 Pa using a tubular air-flow furnace. After carrying out with respect to a sintered compact, it cooled. In order to remove the concentrated portion of the R2-Ga-Cu-Co-based alloy existing in the vicinity of the surface of each sample after the heat treatment, the entire surface of each sample was cut using a surface grinder, and 4.0 mm × 4. A cubic sample (R-T-B system sintered magnet) of 0 mm × 4.0 mm was obtained. In addition, the heating temperature of the R2-Ga-Cu-Co-based alloy and the R1-T1-B-based sintered body in the step of performing the first heat treatment, and R1-T1-B in the step of performing the second heat treatment The heating temperature of the sintered system was measured by attaching a thermocouple.

[sample test]
The obtained sample, the B _r and H _cJ of the sample obtained was measured by B-H tracer. Table 3 shows the measurement results. As Table 3, the present invention examples of the Co content is less than 10 mass% ultra 45Mass% of R2-Cu-Ga-Fe-based alloy it can be seen that the high B _r and a high H _cJ are achieved. On the other hand, in the sample No. 2 in which the Co content of the R2-Ga-Cu-Co-based alloy is 10 mass% or less, and the Co content <Ga content. In 1-1 and 1-2, high _Br is not obtained. Further, the sample No. in which the Co content of the R2-Cu-Ga-Co-based alloy exceeds 45 mass%, and the Pr content <Co content. As for 1-7, high _HcJ is not obtained.

Experimental example 2
[Step of preparing R1-T1-B based sintered body]
A sintered body was produced in the same manner as in Experimental Example 1 except that each element was weighed so that the R1-T1-B based sintered body had a composition indicated by reference numeral 2-A in Table 4. In addition, sintering was performed in the range of 1000 ° C. or more and 1050 ° C. or less (a temperature at which sufficient densification by sintering is selected for each sample). The density of the obtained sintered body was 7.5 Mg / m ³ or more. Table 4 shows the results of the components of the obtained sintered body. Each component in Table 4 was measured by the same method as in Experimental Example 1. In addition, as a result of measuring the oxygen content of the sintered body by the gas melting-infrared absorption method, it was confirmed that all were around 0.2 mass%. Further, C (carbon content) was measured using a gas analyzer based on a combustion-infrared absorption method, and as a result, it was confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Cu-Co-based alloy]
The R2-Ga-Cu-Co-based alloy was R2-Ga-Cu- in the same manner as in Experimental Example 1 except that each element was weighed so that the R2-Ga-Cu-Co-based alloy had a composition indicated by reference numerals 2-a to 2-m in Table 5. A Co-based alloy was prepared. Table 5 shows the composition of the R2-Ga-Cu-Co alloy. Each component in Table 5 was measured by the same method as in Experimental Example 1.

[Step of performing first heat treatment]
The first heat treatment is performed in the same manner as in Experimental Example 1 except that the R2-Ga-Cu-Co-based alloy and the R1-T1-B-based sintered body are heated at the temperature and time shown in Table 6 for the first heat treatment. Carried out.

[Step of performing second heat treatment]
The second heat treatment is performed in the same manner as in Experimental Example 1 except that the R2-Ga-Cu-Co-based alloy and the R1-T1-B-based sintered body are heated at the temperature and time shown in the second heat treatment of Table 6. Carried out. Each sample after the heat treatment was processed in the same manner as in Experimental Example 1 to obtain an RTB-based sintered magnet.

[sample test]
The obtained sample of B _r and H _cJ was measured by B-H tracer. Table 6 shows the measurement results. As shown in Table 6, the R2 amount of the R2-Ga-Cu-Co-based alloy is 35 mass% or more and less than 85 mass%, the Ga amount is 2.5 mass% or more and 30 mass% or less, the Cu amount is 2.5 mass% or more and 20 mass% or less, and the present invention examples in a composition satisfying the inequality of content> content of Co> content of Ga> content of Cu of R2 it is found that a high B _r and a high H _cJ are achieved. On the other hand, any of R, Cu, and Ga in the R2-Ga-Cu-Co-based alloy is out of the scope of the present disclosure (R2 and Co are out of range, sample No. 2-4, 2-6, and 2-12 are out of range for Ga, sample Nos. 2-7 and 2-9 are out of range for Cu, and sample No. 2-13 is out of range for Cu and Ga) Or a composition that does not satisfy the inequality of R2 content> Co content> Ga content> Cu content (Sample No. 2-8 is Ga content <Cu content, Sample No. 2) When -10 is Co content <Ga content), high H _cJ cannot be obtained. Thus, the content of R, Cu, Ga (and Co as shown in Experimental Example 1) in the R2-Ga-Cu-Co-based alloy is within the scope of the present disclosure, and the content of R2> the content of Co. by having a composition satisfying the formula of the content of an amount> the content of Ga> Cu, it is possible to obtain a high B _r and a high H _cJ.

Experimental example 3
[Step of preparing R1-T1-B based sintered body]
A sintered body was produced in the same manner as in Experimental Example 1 except that each element was weighed so that the R1-T1-B-based sintered body had a composition indicated by reference numeral 3-A in Table 7. In addition, sintering was performed in the range of 1000 ° C. or more and 1050 ° C. or less (a temperature at which sufficient densification by sintering is selected for each sample). The density of the obtained sintered body was 7.5 Mg / m ³ or more. The results of the components of the obtained sintered body are shown in Table 7. Each component in Table 7 was measured by the same method as in Experimental Example 1. In addition, as a result of measuring the oxygen content of the sintered body by the gas melting-infrared absorption method, it was confirmed that all were around 0.2 mass%. Further, C (carbon content) was measured using a gas analyzer based on a combustion-infrared absorption method, and as a result, it was confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Cu-Co-based alloy]
The R2-Ga-Cu-Co-based alloy was prepared in the same manner as in Experimental Example 1 except that each element was weighed so that the R2-Ga-Cu-Co-based alloy had a composition indicated by reference numeral 3-a in Table 8. Got ready. Table 8 shows the composition of the R2-Ga-Cu-Co alloy. Each component in Table 8 was measured by the same method as in Experimental Example 1.

[Step of performing first heat treatment]
The first heat treatment is performed in the same manner as in Experimental Example 1 except that the R2-Ga-Cu-Co-based alloy and the R1-T1-B-based sintered body are heated at the temperature and time shown in Table 9 for the first heat treatment. Carried out.

[Step of performing second heat treatment]
The second heat treatment is performed in the same manner as in Experimental Example 1 except that the R2-Ga-Cu-Co-based alloy and the R1-T1-B-based sintered body are heated at the temperature and time shown in Table 9 for the second heat treatment. Carried out. Each sample after the heat treatment was processed in the same manner as in Experimental Example 1 to obtain an RTB-based sintered magnet.

[sample test]
The obtained sample of B _r and H _cJ was measured by B-H tracer. Table 9 shows the measurement results. As shown in Table 9, the first heat treatment temperature (700 ° C. or higher 1100 ° C. or less) and the present invention embodiment is a second heat treatment temperature (450 ° C. or higher 600 ° C. or less) of the present disclosure is higher B _r and a high H _cJ is obtained You can see that Further, as shown in Table 9, higher H _cJ is obtained when the temperature in the first heat treatment is 800 ° C. or higher and 1000 ° C. or lower and the temperature in the second heat treatment is 480 ° C. or higher and 560 ° C. or lower. On the other hand, either the first heat treatment temperature or the second heat treatment temperature is outside the scope of the present disclosure (sample No. 3-1 is out of the first heat treatment range, sample Nos. 3-4 and 3-9 are If the second heat treatment is out of range, high H _cJ cannot be obtained.

<Example of the second embodiment>
Experimental Example 4
[Step of preparing R1-T1-Cu-B-based sintered body]
Each element was weighed so that the R1-T1-Cu-B-based sintered body had the signs 4-A to 4-E in Table 10 and cast by the strip casting method, and flakes having a thickness of 0.2 to 0.4 mm A raw material alloy was obtained. The obtained flaky raw material alloy was pulverized with hydrogen, heated to 550 ° C. in a vacuum and then cooled to obtain a coarsely pulverized powder. Next, after adding and mixing 0.04 mass% of zinc stearate as a lubricant with respect to 100 mass% of the coarsely pulverized powder, the resulting coarsely pulverized powder is mixed with nitrogen using an airflow pulverizer (jet mill device). Dry pulverization was performed in an air stream to obtain finely pulverized powder (alloy powder) having a particle diameter D ₅₀ of 4 μm. The particle diameter D ₅₀ is a volume center value (volume reference median diameter) obtained by a laser diffraction method using an airflow dispersion method.

  To the finely pulverized powder, zinc stearate as a lubricant was added and mixed in an amount of 0.05 mass% with respect to 100 mass% of the finely pulverized powder, and then molded in a magnetic field to obtain a molded body. In addition, what was called a perpendicular magnetic field shaping | molding apparatus (transverse magnetic field shaping | molding apparatus) with which the magnetic field application direction and the pressurization direction orthogonally crossed was used for the shaping | molding apparatus.

The obtained molded body was sintered at 1000 ° C. or higher and 1050 ° C. or lower (a temperature at which sufficient densification by sintering was selected for each sample) for 4 hours and then rapidly cooled to obtain an R1-T1-B system sintering. Got the body. The density of the obtained sintered body was 7.5 Mg / m ³ or more. Table 10 shows the results of the components of the obtained sintered body. Each component in Table 10 was measured using high frequency inductively coupled plasma optical emission spectrometry (ICP-OES). In addition, as a result of measuring the oxygen content of the sintered body by the gas melting-infrared absorption method, it was confirmed that all were around 0.2 mass%. Further, C (carbon content) was measured using a gas analyzer based on a combustion-infrared absorption method, and as a result, it was confirmed that it was around 0.1 mass%. “[T1] / [B]” in Table 10 is obtained by dividing the analysis value (mass%) by the atomic weight of each element for each element (here, Fe, Al, Si, Mn) constituting T1. Is the ratio (a / b) between the sum of these values (a) and the B analysis value (mass%) divided by the atomic weight of B (b). The same applies to all the tables below. In addition, even if each composition of Table 10, oxygen amount, and carbon amount are totaled, 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 R2-Ga-Co alloy]
Each element is weighed so that the R2-Ga-Co-based alloy has the composition indicated by 4-a in Table 11, the raw materials are dissolved, and a ribbon or flake is obtained by a single roll rapid quenching method (melt spinning method). A shaped alloy was obtained. The obtained alloy was pulverized in an argon atmosphere using a mortar, and then passed through a sieve having an opening of 425 μm to prepare an R2-Ga—Co-based alloy. Table 11 shows the composition of the obtained R2-Ga-Co-based alloy. In addition, each component in Table 11 was measured using the high frequency inductively coupled plasma optical emission spectroscopy (ICP-OES).

[Step of performing first heat treatment]
The R1-T1-Cu-B-based sintered bodies denoted by reference numerals 4-A to 4-E in Table 10 were cut and machined to form a rectangular parallelepiped (10.0 mm × 11.11 mm) of 4.4 mm × 10.0 mm × 11.0 mm. The 0 mm plane was a plane perpendicular to the orientation direction). Next, as shown in FIG. 3, a surface perpendicular to the orientation direction (arrow direction in the figure) of the R1-T1-Cu—B based sintered body 1 is mainly present in the processing container 3 made of niobium foil. In order to come into contact with the R2-Ga-Co-based alloy 2, the R2-Ga-Co-based alloy denoted by reference numeral 4-a shown in Table 11 is fired from the R1-T1-Cu-B-based firing denoted by reference numerals 4-A to 4-E. A total of 20 mass% was arranged 10 mass% with respect to the weight of the R1-T1-Cu-B sintered body above and below the bonded body. Next, in a reduced pressure argon controlled to 200 Pa using a tubular air-flow furnace, the R2-Ga-Co alloy and the R1-T1-Cu-B system firing were performed at the temperature and time shown in the first heat treatment of Table 12. The bonded body was heated and subjected to the first heat treatment, and then cooled.

[Step of performing second heat treatment]
R1-T1-B system in which the first heat treatment was carried out at a temperature and time shown in the second heat treatment of Table 12 in a reduced pressure argon controlled to 200 Pa using a tubular air furnace. After carrying out with respect to a sintered compact, it cooled. In order to remove the concentrated portion of the R2-Ga-Co-based alloy existing near the surface of each sample after the heat treatment, the entire surface of each sample was cut using a surface grinder, and 4.0 mm x 4.0 mm x A 4.0 mm cubic sample (RTB-based sintered magnet) was obtained. Note that the heating temperature of the R2-Ga-Co alloy and the R1-T1-Cu-B-based sintered body in the step of performing the first heat treatment, and R1-T1-Cu- in the step of performing the second heat treatment. The heating temperature of the B-based sintered body was measured by attaching a thermocouple.

[sample test]
Each sample of B _r and H _cJ obtained was measured by B-H tracer. Table 12 shows the measurement results. As shown in Table 12, the sample No. 1 in which the Cu content of the R1-T1-Cu-B-based sintered body is less than 0.1 mass%. As for 4-1, high _HcJ is not obtained. In addition, Sample No. in which the Cu content exceeds 1.5 mass%. 4-5 does not obtain a high B _r and H _cJ.

Experimental Example 5
[Step of preparing R1-T1-Cu-B-based sintered body]
A sintered body was produced in the same manner as in Experimental Example 4 except that each element was weighed so that the R1-T1-Cu-B-based sintered body had a composition indicated by reference numeral 5-A in Table 13. The density of the obtained sintered body was 7.5 Mg / m ³ or more. Table 13 shows the results of the components of the obtained sintered body. Each component in Table 13 was measured by the same method as in Experimental Example 4. In addition, as a result of measuring the oxygen content of the sintered body by the gas melting-infrared absorption method, it was confirmed that all were around 0.2 mass%. Further, C (carbon content) was measured using a gas analyzer based on a combustion-infrared absorption method, and as a result, it was confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Co alloy]
The R2-Ga-Co-based alloy was prepared in the same manner as in Experimental Example 4 except that each element was weighed so that the R2-Ga-Co-based alloy had a composition represented by reference numerals 5-a to 5-g in Table 14. Got ready. Table 14 shows the composition of the R2-Ga-Co alloy. Each component in Table 14 was measured by the same method as in Experimental Example 4.

[Step of performing first heat treatment]
The first heat treatment was performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B-based sintered body were heated at the temperature and time shown in Table 15 for the first heat treatment. did.

[Step of performing second heat treatment]
The second heat treatment was performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B-based sintered body were heated at the temperature and time shown in the second heat treatment of Table 15. did. Each sample after the heat treatment was processed in the same manner as in Experimental Example 4 to obtain an RTB-based sintered magnet.

[sample test]
Each sample of B _r and H _cJ obtained was measured by B-H tracer. Table 15 shows the measurement results. As Table 15, the present invention example Co amount of R-Ga-Co-based alloy is at most 10 mass% ultra 45Mass% It can be seen that the high B _r and a high H _cJ are achieved. In contrast, Sample No. in which the Co content of the R—Ga—Co alloy is 10 mass% or less and the Co content is less than the Ga content. 5-1 and 5-2 are not high B _r is obtained. Further, the sample No. in which the Co content of the R—Ga—Co-based alloy exceeds 45 mass% and the Pr content <Co content is satisfied. As for 5-7, high _HcJ is not obtained.

Experimental Example 6
[Step of preparing R1-T1-Cu-B-based sintered body]
A sintered body was produced in the same manner as in Experimental Example 4 except that each element was weighed so that the R1-T1-Cu-B-based sintered body had a composition indicated by reference numeral 6-A in Table 16. The density of the obtained sintered body was 7.5 Mg / m ³ or more. Table 16 shows the results of the components of the obtained sintered body. Each component in Table 16 was measured by the same method as in Experimental Example 4. In addition, as a result of measuring the oxygen content of the sintered body by the gas melting-infrared absorption method, it was confirmed that all were around 0.2 mass%. Further, C (carbon content) was measured using a gas analyzer based on a combustion-infrared absorption method, and as a result, it was confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Co alloy]
The R2-Ga-Co-based alloy was prepared in the same manner as in Experimental Example 4 except that each element was weighed so that the R2-Ga-Co-based alloy had a composition indicated by reference numerals 6-a to 6-i in Table 17. Got ready. Table 17 shows the composition of the R2-Ga-Co alloy. Each component in Table 17 was measured by the same method as in Experimental Example 4.

[Step of performing first heat treatment]
The first heat treatment was performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B sintered body were heated at the temperature and time shown in Table 18 for the first heat treatment. did.

[Step of performing second heat treatment]
The second heat treatment was performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B sintered body were heated at the temperature and time shown in the second heat treatment of Table 18. did. Each sample after the heat treatment was processed in the same manner as in Experimental Example 4 to obtain an RTB-based sintered magnet.

[sample test]
Each sample of B _r and H _cJ obtained was measured by B-H tracer. The measurement results are shown in Table 18. As shown in Table 18, the R2-Ga-Co-based alloy has an R2 content of 35 mass% to 87 mass%, a Ga content of 2.5 mass% to 30 mass%, and an R2 content> Co content> Ga content. the present invention examples in a composition satisfying the inequality is seen that a high B _r and a high H _cJ are achieved. On the other hand, either R or Ga in the R2-Ga-Co-based alloy is out of the scope of the present disclosure (R2 is out of range for sample No. 6-1 and R2 and Co are out of range for sample No. 6-3. Sample Nos. 6-4, 6-6 and 6-9 are compositions that do not satisfy the inequality of R2 content> Co content> Ga content (Sample No. 6). If -7 is Co content <Ga content), high H _cJ cannot be obtained. Thus, the content of R, Ga (and Co as shown in Experimental Example 5) in the R2-Ga-Cu-Co-based alloy is within the scope of the present disclosure, and the content of R2> the content of Co> by a composition satisfying the inequality of the content of Ga, it is possible to obtain a high B _r and a high H _cJ.

Experimental Example 7
[Step of preparing R1-T1-B based sintered body]
A sintered body was produced in the same manner as in Experimental Example 4 except that each element was weighed so that the R1-T1-B based sintered body had a composition indicated by reference numeral 7-A in Table 19. The density of the obtained sintered body was 7.5 Mg / m ³ or more. Table 19 shows the results of the components of the obtained sintered body. Each component in Table 19 was measured by the same method as in Experimental Example 4. In addition, as a result of measuring the oxygen content of the sintered body by the gas melting-infrared absorption method, it was confirmed that all were around 0.2 mass%. Further, C (carbon content) was measured using a gas analyzer based on a combustion-infrared absorption method, and as a result, it was confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Co alloy]
An R2-Ga-Co-based alloy was prepared in the same manner as in Experimental Example 4 except that each element was weighed so that the R2-Ga-Co-based alloy had a composition indicated by reference numeral 7-a in Table 20. Table 20 shows the composition of the R2-Ga-Co alloy. Each component in Table 20 was measured by the same method as in Experimental Example 4.

[Step of performing first heat treatment]
The first heat treatment was performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B-based sintered body were heated at the temperature and time shown in Table 21 for the first heat treatment. did.

[Step of performing second heat treatment]
The second heat treatment was performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B sintered body were heated at the temperature and time shown in the second heat treatment of Table 21. did. Each sample after the heat treatment was processed in the same manner as in Experimental Example 4 to obtain an RTB-based sintered magnet.

[sample test]
The obtained sample was measured B _r and H _cJ of the sample by B-H tracer. Table 21 shows the measurement results. As Table 21, the first heat treatment temperature (700 ° C. or higher 1100 ° C. or less) and the present invention embodiment is a second heat treatment temperature (450 ° C. or higher 600 ° C. or less) of the present disclosure is higher B _r and a high H _cJ is obtained You can see that Further, as shown in Table 21, higher H _cJ is obtained when the temperature in the first heat treatment is 800 ° C. or more and 1000 ° C. or less and the temperature in the second heat treatment is 480 ° C. or more and 560 ° C. or less. On the other hand, either the first heat treatment temperature or the second heat treatment temperature is out of the scope of the present disclosure (Sample No. 7-1 is out of the first heat treatment, Samples No. 7-4 and 7-9 are out of range) If the second heat treatment is out of range, high H _cJ cannot be obtained.

  R-T-B sintered magnets obtained by the present disclosure include various motors such as voice coil motors (VCM) for hard disk drives, motors for electric vehicles (EV, HV, PHV, etc.), motors for industrial equipment, It can be suitably used for home appliances and the like.

1 R1-T1-B sintered body (R1-T1-Cu-B sintered body)
2 R2-Ga-Cu-Co alloy (R2-Ga-Co alloy)
3 Processing Vessel 12 Main Phase 14 Grain Boundary Phase 14a Two Grain Boundary Phase 14b Grain Boundary Triple Point

Claims (16)

Preparing an R1-T1-B-based sintered body;
Preparing an R2-Ga-Cu-Co-based alloy;
At least a part of the R2-Ga-Cu-Co-based alloy is brought into contact with at least a part of the surface of the R1-T1-B-based sintered body, and is 700 ° C or higher and 1100 ° C or lower in a vacuum or an inert gas atmosphere. Performing a first heat treatment at a temperature of
A step of performing a second heat treatment at a temperature of 450 ° C. or higher and 600 ° C. or lower in a vacuum or an inert gas atmosphere on the R1-T1-B sintered body on which the first heat treatment has been performed;
Including
In the R1-T1-B based sintered body,
R1 is at least one kind of rare earth elements, and always contains at least one of Nd and Pr, and the content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-B sintered body,
T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, T1 always contains Fe, and the content of Fe with respect to the entire T1 is 80 mass% or more,
The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0,
In the R2-Ga-Cu-Co alloy,
R2 is at least one of rare earth elements, and necessarily contains at least one of Nd and Pr, and the content of R2 is 35 mass% or more and less than 85 mass% of the entire R2-Ga-Cu-Co-based alloy,
The Ga content is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Cu-Co-based alloy,
The Cu content is 2.5 mass% or more and 20 mass% or less of the entire R2-Ga-Cu-Co-based alloy,
The Co content is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Cu-Co-based alloy,
An R-T-B system sintered magnet manufacturing method in which the inequality of R2 content> Co content> Ga content> Cu content is satisfied.   The manufacturing method of the RTB system sintered magnet according to claim 1 whose molar ratio ([T1] / [B]) of T1 to B is 14.5 or more and 15.0 or less.   The manufacturing method of the RTB system sintered magnet according to claim 1 or 2 whose 50 mass% or more of R2 in said R2-Ga-Cu-Co system alloy is Pr.   The manufacturing method of the RTB system sintered magnet according to claim 1 or 2 whose 70 mass% or more of R2 in said R2-Ga-Cu-Co system alloy is Pr.   The RTB-based sintered magnet according to any one of claims 1 to 4, wherein the total content of R2-Ga-Cu-Co in the R2-Ga-Cu-Co-based alloy is 80 mass% or more. Production method.   The manufacturing method of the RTB type | system | group sintered magnet in any one of Claim 1 to 5 whose temperature in said 1st heat processing is 800 degreeC or more and 1000 degrees C or less.   The manufacturing method of the RTB type | system | group sintered magnet in any one of Claim 1 to 6 whose temperature in said 2nd heat processing is 480 degreeC or more and 560 degrees C or less. The step of preparing the R1-T1-B-based sintered body includes pulverizing the raw material alloy so that the particle size D ₅₀ is 3 μm or more and 10 μm or less, and then orienting the raw alloy in a magnetic field to perform sintering. To 7. The method for producing an RTB-based sintered magnet according to any one of 7 to 7. A step of preparing an R1-T1-Cu-B-based sintered body;
Preparing an R2-Ga-Co-based alloy;
At least a part of the R2-Ga-Co-based alloy is brought into contact with at least a part of the surface of the R1-T1-Cu-B-based sintered body, and is 700 ° C to 1100 ° C in a vacuum or an inert gas atmosphere. Performing a first heat treatment at a temperature of
Performing a second heat treatment on the R1-T1-Cu-B-based sintered body subjected to the first heat treatment at a temperature of 450 ° C. or higher and 600 ° C. or lower in a vacuum or an inert gas atmosphere; ,
Including
In the R1-T1-Cu-B based sintered body,
R1 is at least one of rare earth elements, and always contains at least one of Nd and Pr, and the content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-Cu-B-based sintered body,
T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, T1 always contains Fe, and the content of Fe with respect to the entire T1 is 80 mass% or more,
The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0,
The Cu content is 0.1 mass% or more and 1.5 mass% or less of the entire R1-T1-Cu-B sintered body,
In the R2-Ga-Co alloy,
R2 is at least one kind of rare earth elements, and necessarily contains at least one of Nd and Pr, and the content of R2 is 35 mass% or more and less than 87 mass% of the entire R2-Ga-Co-based alloy,
The Ga content is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Co-based alloy,
Co content is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Co-based alloy,
The inequality of the content of R2> the content of Co> the content of Ga holds.
Manufacturing method of RTB-based sintered magnet.   The manufacturing method of the RTB system sintered magnet according to claim 9 whose molar ratio ([T1] / [B]) of T1 to B is 14.3 or more and 15.0 or less.   The manufacturing method of the RTB system sintered magnet according to claim 9 or 10 whose 50 mass% or more of R2 in said R2-Ga-Co system alloy is Pr.   The manufacturing method of the RTB system sintered magnet according to claim 9 or 10 whose 70 mass% or more of R2 in said R2-Ga-Co system alloy is Pr.   The method for producing an RTB-based sintered magnet according to any one of claims 9 to 12, wherein the total content of R2, Ga, and Co in the R2-Ga-Co-based alloy is 80 mass% or more.   The manufacturing method of the RTB type | system | group sintered magnet in any one of Claim 9 to 13 whose temperature in said 1st heat processing is 800 degreeC or more and 1000 degrees C or less.   The manufacturing method of the RTB type | system | group sintered magnet in any one of Claim 9 to 14 whose temperature in said 2nd heat processing is 480 degreeC or more and 560 degrees C or less. Preparing the R1-T1-Cu-B based sintered body comprises performing after the material alloy particle size D ₅₀ was pulverized to 3μm or 10μm or less, the sintering being oriented in a magnetic field, wherein Item 16. A method for producing an RTB-based sintered magnet according to any one of Items 9 to 15.

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