Rare earth magnet molded body and manufacturing method for rare earth magnet molded body

Abstract

This rare earth magnet molded body contains SmFeN, has a density of 6.37 g / cm3 or more, and has an orientation degree of 82% or more.

Description

Rare earth magnet molding and method for manufacturing rare earth magnet molding

[0001] The present invention relates to a rare earth magnet molding and a method for manufacturing a rare earth magnet molding.

[0002] As a rare earth magnet molding, one using SmFeN is known. For example, Patent Document 1 (JP 2020-53437 A) describes a rare earth magnet molding containing Sm, Fe, and N, at least a portion of which is Th. ２ Zn １７ Type or Th ２ Ni １７ The present invention discloses a rare earth magnet comprising a main phase having a crystal structure of the type Zn, a subphase containing Zn and Fe and existing around the main phase, and an intermediate phase containing Sm, Fe, and N, as well as Zn, existing between the main phase and the subphase, wherein the average Fe content of the subphase is 33 atomic % or less relative to the total amount of the subphase.

[0003] Rare earth magnet moldings are sometimes required to have high magnetic flux density. Furthermore, rare earth magnet moldings are sometimes required to have high strength. For example, magnets used in drive motors for electric vehicles are required to have high magnetic flux density and high flexural strength.

[0004] It would be useful if either one of the magnetic flux density and strength could be improved. Therefore, an object of the present invention is to provide a rare earth magnet molding containing SmFeN that has high magnetic flux density or high strength.

[0005] In one embodiment, the rare earth magnet molding according to the present invention contains a magnetic phase containing Sm, Fe, and N, and has a density of 6.37 g / cm ３ The fiber has a density of 82% or more and an orientation degree of 82% or more.

[0006] In another embodiment, the rare earth magnet molding according to the present invention has a main phase and a mixed phase surrounding the main phase. The main phase is formed of a magnetic phase containing Sm, Fe, and N. The mixed phase is formed of a mixture of a Zn-containing metal and SmFeN. The Fe content (atomic %) in the mixed phase is greater than the Zn content (atomic %).

[0007] In another aspect, the present invention relates to a method for producing the rare earth magnet molding described above, the method comprising the steps of: mixing SmFeN powder with a Zn-containing metal powder to prepare a mixed powder; compacting the mixed powder to obtain a compact; and heat-treating the compact.

[0008] FIG. 1 is a flowchart illustrating a method for manufacturing a rare earth magnet molding according to the present embodiment. FIG. 2 is a plan view illustrating an example of a rare earth magnet molding according to a second embodiment. FIG. 3A is a diagram illustrating an element map of a rare earth magnet laminate according to Example 2-1. FIG. 3B is a diagram illustrating the results of a line analysis along the arrow portion in FIG. 3A. FIG. 4A is a diagram illustrating the results of an EPMA analysis of Comparative Example 2-1. FIG. 4B is a diagram illustrating the results of an EPMA analysis of Comparative Example 2-1.

[0009] (1) First Embodiment First, the first embodiment will be described. The inventors discovered that by increasing the density and degree of orientation of a rare earth magnet molding, it is possible to increase the magnetic flux density and strength. That is, the rare earth magnet molding according to this embodiment is a magnet molding containing a magnetic phase containing Sm, Fe, and N, and has high density and high degree of orientation. Specifically, the rare earth magnet molding has a density of 6.37 g / cm. ３ The rare earth magnet molding has a density of 100% or more and an orientation degree of 82% or more. (Density) In this specification, when the term "density" is used simply, it refers to the density of the rare earth magnet molding itself. When the rare earth magnet molding contains components other than the magnetic phase, it refers to the density of the rare earth magnet molding including the components other than the magnetic phase. In other words, "density" is a value determined from the mass and volume of the rare earth magnet molding.

[0010] If a rare earth magnet molding has a high density, the number of voids in the molding will be reduced. As a result, the proportion of non-magnetic components in the molding that do not function as a magnet will be reduced, improving the magnetic flux density. In addition, if the density is high, the flexural strength of the rare earth magnet molding will also be improved. ３ By satisfying the above conditions, a sufficiently high magnetic flux density and a sufficiently high bending strength can be obtained. Preferably, the density of the rare earth magnet molding is 6.50 g / cm or less. ３More preferably, the density of the rare earth magnet molding is 6.80 g / cm ３ The upper limit of the density of the rare earth magnet molding is not particularly limited, but is, for example, 7.68 g / cm ３ or less, or 7.50 g / cm ３ (Orientation Degree) As described above, the rare earth magnet molding according to this embodiment has a high degree of orientation. Specifically, it has a degree of orientation of 82% or more. Increasing the degree of orientation also improves the magnetic flux density. Preferably, the degree of orientation is 85% or more. More preferably, the degree of orientation is 89% or more. There is no particular upper limit to the degree of orientation, but it is, for example, 99% or less, or 95% or less.

[0011] The degree of orientation is calculated by "Br / Bs." Here, Br refers to the residual magnetic flux density. Bs refers to the saturation magnetic flux density. Br and Bs can be calculated, for example, by measuring the magnetic properties using a BH tracer. That is, Br and Bs can be calculated by obtaining the magnetic property loop (demagnetization curve) of the rare earth magnet molding using a BH tracer, and the degree of orientation can be calculated from the obtained Br and Bs. (Magnetic Flux Density and Flexural Strength) The rare earth magnet molding according to this embodiment has the density and degree of orientation described above, thereby achieving high magnetic flux density and high flexural strength. For example, the magnetic flux density of the rare earth magnet molding is 0.81 (T) or more. In a preferred embodiment, the magnetic flux density is 0.90 (T) or more. The flexural strength is, for example, 80 MPa or more. In a preferred embodiment, the flexural strength is 100 MPa or more.

[0012] Since the rare earth magnet molding according to this embodiment can achieve high magnetic flux density and high flexural strength, it is suitable for use as a magnet molding for a drive motor of an electric vehicle. A magnet molding used as a drive motor of an electric vehicle is required to have high flexural strength in addition to high magnetic flux density in order to cope with high speed rotation. The rare earth magnet molding according to this embodiment can satisfy such requirements and is therefore suitable for use as a drive motor of an electric vehicle. (Magnetic Phase Containing Sm, Fe, and N) As described above, the rare earth magnet molding contains a phase containing Sm, Fe, and N as a magnetic phase. Specifically, it contains SmFeN. SmFeN is a magnetic component. There is no particular limitation on SmFeN, but examples thereof include Sm ２ Fe １７ N ３ The content of SmFeN in the rare earth magnet molding is, for example, 80 mass % or more, preferably 85 mass % or more, and more preferably 85 to 95 mass %.

[0013] In a preferred embodiment, SmFeN is （１－ｉ） Ri) ２ (Fe （１－ｊ） Co ｊ ) 17N ｈ (wherein R is at least one selected from rare earth elements other than Sm, Y and Zr, i is 0 to 0.50, j is 0 to 0.52, and h is 1.5 to 4.5). That is, in one embodiment, the magnetic phase is represented by (Sm （１－ｉ） Ri) ２ (Fe （１－ｊ） Co ｊ ) 17N ｈ(where R is one or more rare earth elements other than Sm, Y, and Zr, i is 0 to 0.50, j is 0 to 0.52, and h is 1.5 to 4.5). (Zn-Containing Metal) The rare earth magnet molding preferably contains a Zn-containing metal as a binder. The Zn-containing metal may be Zn alone (metallic zinc) or an alloy containing Zn. The Zn content in the rare earth magnet molding is, for example, 1 to 20 mass%, preferably 3 to 13 mass%. If Zn is contained in such an amount, the rare earth magnet molding can be easily solidified (molded) during production. As a result, a high density can be easily obtained. Furthermore, impurity phases present on the surface of the SmFeN powder are neutralized by Zn, thereby achieving a high coercive force. (Solid Lubricant) The rare earth magnet molding preferably contains a solid lubricant. The use of a solid lubricant makes it easier to increase the density and degree of orientation.

[0014] The solid lubricant is not particularly limited, but examples thereof include fatty acid esters, metal soaps, and waxes. Specific examples include zinc stearate, lithium stearate, calcium stearate, magnesium stearate, methyl laurate, and methyl caproate, with zinc stearate being preferred. Note that the zinc stearate referred to here is a different substance from the Zn-containing metal used as the binder.

[0015] The content of the solid lubricant in the rare earth magnet molding is, for example, 0.05 to 5 mass %, preferably 0.1 to 2.0 mass %. (Manufacturing Method) A rare earth magnet molding having the density and degree of orientation described above can be obtained by adopting manufacturing conditions that increase the density and degree of orientation. An example of a manufacturing method for a rare earth magnet molding according to this embodiment is described below.

[0016] FIG. 1 is a flowchart illustrating a method for manufacturing a rare earth magnet molding according to this embodiment. As shown in FIG. 1, this manufacturing method generally includes the steps of preparing SmFeN powder (S1), mixing the Zn-containing metal powder with the SmFeN powder (S2), compacting (S3), and heat treatment (S4). Each step is described in detail below. <S1> Preparation of SmFeN Powder (S1-1) First, SmFeN coarse powder is prepared. Commercially available SmFeN coarse powder can be used. SmFeN coarse powder can have a particle size of 10 to 20 μm. In this specification, the particle size of a substance can be determined by the D50 value, which is determined by measuring the particle size distribution using a laser diffraction / scattering particle size distribution analyzer. (S1-2) If a solid lubricant is used, the solid lubricant is added to the SmFeN coarse powder. The solid lubricant and SmFeN are mixed, for example, using a resonant acoustic mixer in a dry atmosphere. The resonant acoustic mixer will be described later. (S1-3) Next, the SmFeN powder is finely pulverized. For example, the SmFeN powder is pulverized using a jet mill under nitrogen gas spray. (S1-4) Next, the pulverized SmFeN powder is classified. For example, the SmFeN powder can be classified using a rotor classification method. The particle size of the SmFeN powder obtained after classification is, for example, 10 μm or less, preferably 1.0 to 10 μm.

[0017] The SmFeN powder is prepared by the processes S1-1 to S1-4 described above. According to the above process, the addition of a solid lubricant in S1-2 prevents the powder from agglomerating during the fine pulverization (S1-3). Furthermore, the powder is prevented from adhering to the walls of the pulverization device. As a result, the SmFe alloy can be pulverized to the desired particle size.

[0018] In the above-described method, a case where coarse powder of SmFeN is used as the raw material has been described. However, instead of SmFeN, an SmFe alloy may be used as the raw material. In this case, for example, after fine pulverization (S1-3) or classification (S1-4), a nitriding treatment can be performed to obtain SmFeN powder. <S2> Mixing of Zn-containing metal powder and SmFeN powder Next, a Zn-containing metal powder that will serve as a binder is prepared. Then, the SmFeN powder and the Zn-containing metal powder are mixed to obtain a mixed powder.

[0019] In this step, it is preferable to use a resonant acoustic mixer. A resonant acoustic mixer is a mixing device that mixes powders by applying low-frequency vibrations (for example, 10 to 500 Hz, preferably 30 to 90 Hz). Use of a resonant acoustic mixer can increase the density of the final molded body. It can also increase the degree of orientation.

[0020] The particle size of the Zn-containing metal powder used in this step is preferably smaller than that of the SmFeN powder, so that a compact having a high density can be obtained during compaction (step S3).

[0021] The particle size of the Zn-containing metal powder is, for example, 0.1 to 5.0 μm, preferably 0.2 to 1.0 μm. <S3> Compaction (S3-1) Next, the mixed powder is compacted to obtain a compact. Specifically, first, magnetic field compaction is performed as pre-compaction. That is, the mixed powder is compressed in a magnetic field. The strength of the magnetic field is, for example, 10 to 30 kOe, preferably 15 to 25 kOe. The surface pressure during compression is, for example, 0.5 to 10 ton / cm. ２ , preferably 1 to 3 ton / cm ２ This causes the SmFeN powder to be oriented in a specific direction, resulting in a high degree of orientation.

[0022] If the mixed powder contains a solid lubricant, the fluidity of the mixed powder is improved. Therefore, in this step, the SmFeN particles are more likely to be oriented in a direction corresponding to the magnetic field. As a result, a compact with a higher degree of orientation can be obtained. (S3-2) Next, the main compaction is carried out. Specifically, warm compression compaction is carried out. At this time, a pressure of 20 ton / cm is applied. ２ The mixed powder is molded at a surface pressure of 25 tons / cm or more. By molding at such a surface pressure, the density of the resulting molded body becomes sufficiently high. More preferably, it is 25 tons / cm. ２ The mixed powder is compacted under the above surface pressure.

[0023] The molding temperature is, for example, 150 to 300°C, preferably 200 to 250°C. By performing molding at such a temperature, the deformation resistance of the material decreases and the compressibility increases, thereby enabling the density of the obtained molded body to be further increased.

[0024] The mixed powder is molded by the above-described processes S3-1 and S3-2 to obtain a molded body. <S4> Heat Treatment Next, the molded body is heat-treated. The heat treatment is performed, for example, at a temperature of 350 to 450°C. Preferably, the heat treatment temperature is 360 to 400°C. The heat treatment time is, for example, 30 minutes or more, preferably 45 minutes or more, and more preferably 60 to 200 minutes. By performing the heat treatment at such a temperature and time, high density and high degree of orientation are achieved. Furthermore, impurity phases present on the surface of the SmFeN powder are neutralized by Zn during the heat treatment. As a result, the magnetic properties (coercive force) can be improved.

[0025] By the method described above, the rare earth magnet molding according to this embodiment can be obtained. ２ The mixed powder is molded under the above surface pressure and is then heat-treated in step S4, resulting in a high density (specifically, 6.37 g / cm ３ A rare earth magnet molding having a density of 100% or more and a high degree of orientation (specifically, 82% or more) can be obtained. A rare earth magnet molding having such a density and degree of orientation achieves high magnetic flux density and high flexural strength.

[0026] In addition, if a solid lubricant is added in step S1, the density and the degree of orientation can be further increased.

[0027] Furthermore, if a resonant acoustic mixer is used in step S2 (mixing), the density and degree of orientation can be further increased.

[0028] It is preferable that each step from step S1-2 onwards is carried out in a low-oxygen environment (for example, an oxygen concentration of 100 ppm or less). [Experimental Example] Next, an experimental example carried out by the present inventors in relation to the first embodiment will be described.

[0029] Table 1 shows the samples prepared in this experiment and the manufacturing conditions.

[0030]

[0031] As shown in Table 1, rare earth magnet moldings according to Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-3 were produced. Specifically, rare earth magnet moldings were produced by the following method. (Example 1-1) Particle size (D ５０ SmFeN powder with a particle size of 2.7 μm was prepared. On the other hand, Zn powder with a particle size of 0.5 μm was prepared. The SmFeN powder and Zn powder were mixed using a resonant acoustic mixer to obtain a mixed powder. Specifically, the powders were mixed using a resonant acoustic mixer (60 Hz) while applying a maximum acceleration of 80 G in an inert gas atmosphere. The content of Zn powder in the mixed powder was 10 wt %. Next, magnetic field compaction was performed. Specifically, while applying a magnetic field of 21 kOe, 2 ton / cm was applied. ２ The mixed powder was pressed at a surface pressure of 25 ton / cm to obtain a pre-molded body. ２The preliminary compact was warm-pressed at a surface pressure of 1000 psi to obtain a final compact. The resulting final compact was then heat-treated at 385°C for 90 minutes in an argon gas stream. This resulted in a rare earth magnet molding according to Example 1-1. The content of SmFeN powder in the rare earth magnet molding was 90 wt%. (Example 1-2) Zinc stearate was added as a solid lubricant before pulverizing the SmFe alloy. The amount of zinc stearate added was adjusted to provide a final content of approximately 0.5 wt% in the rare earth magnet molding. The remaining conditions were the same as those of Example 1-1, and the rare earth magnet molding according to Example 1-2 was obtained. The content of SmFeN powder in the rare earth magnet molding was calculated by subtracting the Zn used as a binder and the zinc stearate used as a solid lubricant from the total content of the rare earth magnet molding, specifically 89.5 wt%. (Examples 1-3 to 1-8, Comparative Examples 1-2 to 1-3) As shown in Table 1, the particle size of the SmFeN powder, the amount of Zn powder used, the particle size of the Zn powder, the amount of solid lubricant added, the molding surface pressure, and the heat treatment conditions were changed. Other conditions were the same as those of Examples 1-1 and 1-2, and rare earth magnet moldings according to Examples 1-3 to 1-8 and Comparative Examples 1-2 to 1-3 were obtained. (Comparative Example 1-1) As Comparative Example 1, a commercially available bonded magnet (using a resin as a binder) was prepared. (Physical Properties) The magnet density, degree of orientation, magnetic flux density, and flexural strength of the rare earth magnet moldings according to each Example and Comparative Example were measured. The results are shown in Table 2.

[0032]

[0033] As shown in Tables 1 and 2, Examples 1-1 to 1-8 had a tensile strength of 6.37 g / cm ３ The magnets of Examples 1-1 to 1-8 had a density of 0.81 T or more and a degree of orientation of 82% or more. Examples 1-1 to 1-8 also had a higher magnetic flux density and higher flexural strength than Comparative Example 1, which is a commercially available bonded magnet. Specifically, they had a magnetic flux density of 0.81 T or more and a flexural strength of 108 MPa or more.

[0034] In addition, Comparative Examples 1-2 and 1-3 had an orientation degree of 82% or more, but the density was 6.37 g / cm ３Comparative Examples 2 and 3 had high magnetic flux density but low bending strength.

[0035] Examples 1-2 and 1-3 had higher density and orientation than Example 1-1. Furthermore, the magnetic flux density was also high. From this, it can be understood that the addition of a solid lubricant increases the density and orientation, and further increases the magnetic flux density. (2) Second Embodiment Next, a second embodiment will be described.

[0036] As mentioned above, in rare earth magnet moldings having a magnetic phase containing Sm, Fe, and N, the use of a Zn-containing metal as a binder improves the coercive force. Specifically, the oxide phase (α-Fe) formed on the surface of the SmFeN powder reacts with Zn and is rendered harmless. This improves the coercive force. On the other hand, Zn does not function as a magnet. Therefore, increasing the amount of Zn reduces the magnetic flux density. In other words, adding Zn is effective from the perspective of coercive force, but a smaller amount of Zn is better from the perspective of magnetic flux density.

[0037] The inventors of the present invention suspected that even if the amount of Zn was small, coercivity could be maintained if Zn could be distributed throughout the voids between the SmFeN powder particles. They then investigated manufacturing conditions that would allow even a small amount of Zn to be distributed throughout the voids, and were able to obtain a rare earth magnet molding that maintained coercivity while also having a high magnetic flux density.

[0038] In other words, the rare earth magnet molding according to this embodiment is a rare earth magnet molding in which a small amount of Zn is distributed throughout the voids in order to obtain high magnetic flux density while maintaining coercivity. The rare earth magnet molding according to this embodiment will be described in detail below.

[0039] First, the configuration of the rare earth magnet molding according to this embodiment will be described. FIG. 2 is a plan view showing an example of the rare earth magnet molding 1 according to this embodiment, and shows the morphology of Zn by EPMA. As shown in FIG. 2, the rare earth magnet molding 1 according to this embodiment has a main phase 2 and a mixed phase 3 surrounding the main phase 2. The main phase 2 is a phase formed of SmFeN (a magnetic phase containing Sm, Fe, and N). The mixed phase 3 is a phase formed of a mixture of a Zn-containing metal and SmFeN. Here, the Fe content (atomic %) of the mixed phase 3 is greater than the Zn content (atomic %). That is, in this embodiment, the gaps between the main phases 2 are filled with the mixed phase 3. Although the mixed phase 3 is a phase containing Zn, the Zn content is smaller than the Fe content. That is, Zn is distributed throughout the gaps between the main phases 2 at a low concentration.

[0040] The magnitude relationship between the Fe content (atomic %) and the Zn content (atomic %) in the mixed phase 3 can be confirmed, for example, by EPMA. FIG. 3A shows an element map obtained by EPMA analysis of an example of the rare earth magnet molding 1 according to this embodiment. Specifically, it shows an element map of the rare earth magnet laminate according to Example 2-1, which will be described later, and shows an element map of the boundary between the main phase and the mixed phase. FIG. 3B shows the results of a line analysis along the arrow in FIG. 3A. As shown in FIG. 3B, the main phase contains Fe and other elements, but almost no Zn. On the other hand, the mixed phase contains Zn in addition to Fe and other elements. However, the Fe content is greater than the Zn content throughout the mixed phase.

[0041] Preferably, the Fe content (atomic %) in the mixed phase is 30 atomic % or more. Also, preferably, the Fe content (atomic %) in the mixed phase is greater than the contents (atomic %) of any other elements. By adopting such a configuration, a higher magnetic flux density can be obtained.

[0042] The Zn content in the rare earth magnet molding is preferably 13 mass % or less, and more preferably 5 to 13 mass %.

[0043] As mentioned above, a rare earth magnet molding having the above-described configuration can be obtained by adopting manufacturing conditions that allow Zn to be distributed throughout the voids even at low concentrations. For example, it can be obtained by adopting a manufacturing method similar to that of the first embodiment (see FIG. 1 ) and by adopting specific conditions in the mixing step (S2) and the heat treatment step (S4). Below, the manufacturing method of a rare earth magnet molding according to this embodiment will be described, focusing on these steps (S2 and S4). Note that detailed explanations of the same conditions as those in the first embodiment will be omitted. <S2> Mixing of Zn Powder and SmFeN Powder To distribute Zn throughout the entire mixture, it is important that the Zn-containing metal powder and SmFeN powder are thoroughly mixed. Therefore, in this embodiment, the Zn-containing metal powder and SmFeN powder are mixed using a resonant acoustic mixer. Using a resonant acoustic mixer allows the Zn-containing metal powder and SmFeN powder to be uniformly mixed. This allows Zn to be distributed throughout the mixed phase, even if the amount of Zn is minimal.

[0044] In addition, the smaller the particle size of the Zn-containing metal powder, the easier it is for Zn to be distributed throughout the entire powder. Therefore, it is preferable that the particle size (D ５０ ) is the particle size (D ５０ ) is smaller than the value of the Zn content. <S4> Heat Treatment Optimizing the heat treatment conditions also makes it easier for Zn to permeate the entire voids. Specifically, in step S4 (heat treatment), heat treatment is performed at 350 to 400°C for 30 minutes or more. The heat treatment time is preferably 45 minutes or more, and more preferably 45 to 90 minutes. In this step, performing heat treatment for a long period (30 minutes or more) promotes the diffusion of Zn. As a result, Zn can be permeated to every corner of the mixed phase 3. Furthermore, if the heat treatment temperature is 350°C or higher, the diffusion of Zn is promoted and Zn can be permeated to every corner. On the other hand, if the heat treatment temperature is 400°C or lower, the decomposition of SmFeN can be suppressed. The heat treatment temperature is preferably 360 to 400°C.

[0045] As explained above, by optimizing the mixing method in step S2 and the heat treatment conditions in step S4, the rare earth magnet molding according to this embodiment can be obtained. The resulting rare earth magnet molding has a low concentration of Zn distributed throughout the entire mixed phase. Specifically, as shown in FIG. 3B , a rare earth magnet molding having a structure in which the Fe content (atomic %) is greater than the Zn content (atomic %) throughout the entire mixed phase can be obtained. The rare earth magnet molding according to this embodiment can reduce the amount of Zn that does not function as a magnet, thereby improving the magnetic flux density. Meanwhile, because Zn is distributed throughout the entire mixed phase, the oxidized phase on the surface of the main phase is rendered harmless by the Zn, maintaining the coercive force. Therefore, the magnetic flux density can be improved while increasing the coercive force. [Experimental Example] Next, an experimental example conducted by the present inventors in relation to the second embodiment will be described. (Example 2-1) Particle size (D ５０ SmFeN powder with a particle size of 2.7 μm was obtained. On the other hand, Zn powder with a particle size of 0.5 μm was prepared. The SmFeN powder and Zn powder were mixed using a resonant acoustic mixer to obtain a mixed powder. Specifically, the powders were mixed using a resonant acoustic mixer (60 Hz) while applying a maximum acceleration of 80 G in a dry atmosphere. The content of Zn powder in the mixed powder was 10 wt %. Next, magnetic field compaction was performed. Specifically, the powders were mixed using a resonant acoustic mixer (60 Hz) while applying a pressure of 21 kOe and a pressure of 2 ton / cm. ２ The mixed powder was then pressed at a surface pressure of 25 ton / cm at 220°C. ２ The mixed powder was pressed with a surface pressure of 1000 MPa. The resulting compact was then heat-treated at 385°C for 90 minutes. This resulted in a rare earth magnet molding according to Example 2-1. The content of SmFeN powder in the rare earth magnet molding was 90 wt%. (Comparative Example 2-1) The content of Zn powder was changed to 15 wt%. The other conditions were the same as in Example 2-1, and a rare earth magnet molding according to Comparative Example 2-1 was obtained. (Analysis) EPMA analysis was performed on the rare earth magnet moldings according to Example 2-1 and Comparative Example 2-1. The residual magnetic flux (magnetic flux density) and coercive force were also measured.

[0046] As mentioned above, the EPMA analysis results for Example 2-1 are shown in Figures 3A and 3B. Meanwhile, the EPMA analysis results for Comparative Example 2-1 are shown in Figures 4A and 4B. That is, Figure 4A shows an element map obtained by EPMA analysis of the rare earth magnet molding according to Comparative Example 2-1. Furthermore, Figure 4B shows the results of line analysis along the arrow portion in Figure 4A. Furthermore, the measurement results of remanence and coercivity, along with the Zn content (wt), are shown in Table 3 below.

[0047]

[0048] As shown in FIG. 3B , in Example 2-1, the Fe content (atomic %) was higher than the Zn content (atomic %) throughout the entire mixed phase. Specifically, the Fe content (atomic %) in the mixed phase was 30% or higher. Furthermore, the Fe content (atomic %) in the mixed phase was higher than the contents of any other elements. On the other hand, as shown in FIG. 4B , in Comparative Example 2-1, the Zn content (atomic %) was higher than the Fe content (atomic %) in some regions of the mixed phase.

[0049] As shown in Table 3, Example 2-1 showed almost no change in coercivity compared to Comparative Example 2-1, but the magnetic flux density (residual magnetic flux) was significantly higher. This confirmed that by adopting a configuration in which the Fe content (atomic %) in the mixed phase is greater than the Zn content (atomic %), it is possible to increase the magnetic flux density while maintaining the coercivity. [Notes] Below, the main configurations and effects of the above-described embodiment are summarized as notes. (Note 1) A magnetic phase containing Sm, Fe, and N is contained, and the magnetic flux density is 6.37 g / cm ３ A rare earth magnet molding having a density of 82% or more and a degree of orientation of 82% or more.

[0050] According to the above-mentioned configuration, a rare earth magnet molding having high magnetic flux density and high strength can be obtained. (Appendix 2) The rare earth magnet molding according to Appendix 1, further comprising a solid lubricant.

[0051] According to the above-mentioned configuration, the degree of orientation can be further increased, and the magnetic flux density can be further improved. (Appendix 3) The rare earth magnet molding according to Appendix 2, wherein the content of the solid lubricant is 0.05 to 5 mass %.

[0052] According to the above-mentioned configuration, the degree of orientation can be further increased, and the magnetic flux density can be further improved. (Appendix 4) The rare earth magnet molding according to appendix 2 or 3, wherein the solid lubricant contains zinc stearate.

[0053] According to the above-mentioned configuration, the degree of orientation can be further increased, and the magnetic flux density can be further improved. （１－ｉ） Ri) ２ (Fe （１－ｊ） Co ｊ ) 17N ｈ (where R is one or more rare earth elements other than Sm, and Y and Zr, i is 0 to 0.50, j is 0 to 0.52, and h is 1.5 to 4.5). (Appendix 6) A rare earth magnet molding according to any one of Appendices 1 to 4, comprising a phase represented by the formula: (where R is one or more rare earth elements other than Sm, Y and Zr, i is 0 to 0.50, j is 0 to 0.52, and h is 1.5 to 4.5). (Appendix 6) A rare earth magnet molding having a main phase and a mixed phase surrounding the main phase, wherein the main phase is formed of SmFeN, the mixed phase is formed of a mixture of a Zn-containing metal and SmFeN, and the Fe content (atomic %) in the mixed phase is greater than the Zn content (atomic %).

[0054] According to the above-mentioned configuration, it is possible to improve the magnetic flux density while maintaining the coercive force. (Appendix 7) The rare earth magnet molding according to Appendix 6, wherein the Fe content (atomic %) in the mixed phase is 30 atomic % or more.

[0055] According to the above-mentioned configuration, it is possible to improve the magnetic flux density while maintaining the coercive force. (Appendix 8) The rare earth magnet molding according to appendix 6 or 7, wherein the Fe content (atomic %) in the mixed phase is greater than the contents (atomic %) of any other element.

[0056] According to the above-mentioned configuration, it is possible to improve the magnetic flux density while maintaining the coercive force. (Appendix 9) A method for manufacturing a rare earth magnet molding according to any one of Appendices 1 to 8, comprising the steps of: mixing SmFeN powder with a Zn-containing metal powder to prepare a mixed powder; compacting the mixed powder to obtain a compact; and heat-treating the compact.

[0057] According to this method, a rare earth magnet molding having desired properties can be obtained. (Appendix 10) The manufacturing method according to Appendix 9, wherein the particle size of the Zn-containing metal powder is smaller than the particle size of the SmFeN powder.

[0058] According to the above-mentioned method, it is possible to improve the magnetic flux density while maintaining the coercive force. Furthermore, it is possible to obtain a rare earth magnet molding having high density and a high degree of orientation. (Appendix 11) The manufacturing method according to Appendix 9 or 10, wherein the step of preparing the mixed powder includes a step of mixing the SmFeN powder with the Zn-containing metal powder using a resonant acoustic mixer.

[0059] This method can improve the magnetic flux density while maintaining the coercive force, and also can produce a rare earth magnet molding with high density and high degree of orientation.

Claims

1. Contains a magnetic phase containing Sm, Fe, and N, and has a density of 6.37 g / cm ３ A rare earth magnet molding having a density of 82% or more and an orientation degree of 82% or more.

2. A rare earth magnet molding according to claim 1, further comprising a solid lubricant.

3. A rare earth magnet molding according to claim 2, wherein the content of said solid lubricant is 0.05 to 5 mass %.

4. A rare earth magnet molding according to claim 2, wherein the solid lubricant contains zinc stearate.

5. The magnetic phase is (Sm （１－ｉ） Ri) ２ (Fe （１－ｊ） Co ｊ ) 17N ｈ (wherein R is a rare earth element other than Sm and at least one element selected from Y and Zr, i is 0 to 0.50, j is 0 to 0.52, and h is 1.5 to 4.5).

6. A rare earth magnet molding comprising: a main phase; and a mixed phase surrounding the main phase, wherein the main phase is formed of a magnetic phase containing Sm, Fe, and N; the mixed phase is formed of a mixture of a Zn-containing metal and SmFeN; and in the mixed phase, the Fe content (atomic %) is greater than the Zn content (atomic %).

7. A rare earth magnet molding according to claim 6, wherein the mixed phase has an Fe content (atomic %) of 30 atomic % or more.

8. A rare earth magnet molding according to claim 6, wherein the Fe content (atomic %) in the mixed phase is greater than the content (atomic %) of any other element.

9. A method for producing a rare earth magnet molding according to claim 1 or 6, comprising the steps of: mixing SmFeN powder with a Zn-containing metal powder to prepare a mixed powder; compacting the mixed powder to obtain a molded body; and heat treating the molded body.

10. The manufacturing method according to claim 9, wherein the particle size of the Zn-containing metal powder is smaller than the particle size of the SmFeN powder.

11. The manufacturing method according to claim 9, wherein the step of preparing the mixed powder comprises mixing the SmFeN powder with the Zn-containing metal powder using a resonant acoustic mixer.

Images