JP6447380B2 - SmFeN-based metal bond magnet compact with high specific resistance - Google Patents

Description

  The present invention relates to a bonded magnet molded body, and more particularly to a SmFeN-based metal bonded magnet molded body having a large specific resistance.

The Sm—Fe—N compound is used as a magnet material because it has excellent magnet performance. This compound has a problem that at a high temperature of 500 ° C. or higher, the crystal structure cannot be maintained as a stable phase and decomposes. Usually, as a magnet particle obtained by nitriding a Sm ₂ Fe ₁₇ alloy having a particle diameter of several tens of μm or less. It is synthesized. Moreover, as an industrial material, generally, this magnet particle is solidified and molded with a resin and used as a so-called bonded magnet.

  However, by solidifying and molding with resin, various properties such as durability and heat resistance of the solidified molded body are restricted by the material properties of the resin. Therefore, as a metal bond magnet that solidifies and molds magnetic particles using metal as a binder. Attempts have been made to obtain solidified shaped bodies.

  As the metal used as the binder, from the viewpoint of formability, Cu, Al, and other metals that are easily deformed are effective, but many of them are accompanied by a decrease in magnetic properties, and from the viewpoint of coexistence with magnetic properties, non-patent Utilization of Zn has been attempted as in Reference 1.

D. Prabhu et al. / Scripta Materialia 67 (2012) 153-156

  On the other hand, the metal bond magnet of Non-Patent Document 1 or the like has a low electrical resistance, unlike a resin bond magnet hardened with an insulating resin. In particular, the electrical resistance decreases as the amount of added metal (Zn) particles increases. Magnet materials are often used in environments where they themselves undergo magnetic field fluctuations. For example, when used in an application using an electromagnetic force acting between an electromagnet, such as a motor or an actuator, the magnet is used in an environment with a magnetic field variation due to a change in the magnetic force of the electromagnet.

  As a result, there arises a problem that a current due to electromagnetic induction is generated in the magnet due to the magnetic field fluctuation and the magnet itself generates heat. In order to solve this problem, a magnet having a large electrical resistance that reduces the induced current is required.

  However, in the metal bond magnet of Non-Patent Document 1 and the like, the metal (Zn) particles used as the binder have a smaller electric resistance than the magnet particles, and the electric resistance of the bonded magnet molded body that is a solidified molded body after solidification (molding) is low. There was a problem that the heat generation amount was small.

  The present invention has been made in order to solve the above-described problems of the prior art, and even when used in a usage environment subject to magnetic field fluctuations, the bonded magnet has a large electrical resistance that reduces the induced current. It aims at providing a molded object.

  The present inventors have intensively studied to solve the above problems. As a result, the object of the present invention is to provide a nitrogen compound magnet particle containing a Zn alloy having a strain rate sensitivity index (m value) of 0.3 or more and a breaking elongation of 50% or more as a binder, and containing Sm and Fe. This can be achieved by a bonded magnet molded body solidified with a binder.

  According to the present invention, a Zn magnet binder having the above-described physical properties provides a bonded magnet molded body having a large electric resistance that reduces induced current even when used in an environment where magnetic field fluctuations occur. it can.

FIG. 1A is a schematic view showing a preferred example of the mold, and FIG. 1B is a cross-sectional view of the mold of FIG. FIG. 2A is a schematic cross-sectional view schematically showing a rotor structure of a surface magnet type synchronous motor (SMP or SPMSM). FIG. 2B is a schematic cross-sectional view schematically showing a rotor structure of an embedded magnet type synchronous motor (IMP or IPMSM). The range which can be shape | molded by the average particle diameter of a magnet particle and a ZnAl alloy particle is shown about Experimental Examples 1-6 and Comparative Examples 1-5 whose ratio of a ZnAl alloy particle is 5 volume%. With respect to Experimental Examples 1, 7, 8 and Comparative Examples 6 to 8 in which the average particle diameter of ZnAl alloy particles is 10 μm and the average particle diameter of Zn particles is 3 μm, the moldability of ZnAl alloy and metal Zn as a binder is shown. Indicates differences (mouldable or not moldable). For Experimental Examples 1, 7, 8 and Comparative Examples 7-8, in which the average particle diameter of ZnAl alloy particles is 10 μm and the average particle diameter of Zn particles is 3 μm, the ratio (volume%) of ZnAl alloy binder or Zn binder, The relationship of the (electric) specific resistance of a magnet molding is shown.

  Hereinafter, embodiments of the present invention will be described in detail.

(I) Bonded magnet molded body (first embodiment)
In the first embodiment of the present invention, a nitrogen compound magnet particle containing a Zn alloy having a strain rate sensitivity index (m value) of 0.3 or more and a breaking elongation of 50% or more as a binder, and containing Sm and Fe. A bonded magnet molded body, which is solidified with the binder. By having such a configuration, the effects of the above-described invention can be achieved. Hereinafter, the bonded magnet molded body of this embodiment will be described in detail for each constituent requirement.

(1) Zn alloy binder The binder contained in the bonded magnet molded body of the present embodiment is a Zn alloy having a strain rate sensitivity index (m value) of 0.3 or more and a breaking elongation of 50% or more (below the molding temperature). It contains. Here, the reason why the m value is 0.3 or more and the breaking elongation is 50% or more at a molding temperature or lower is that a bonded magnet molded body containing a binder that satisfies the requirements can have fine crystal grains. If the crystal grains are fine, it is possible to obtain characteristics that are excellent in superplastic characteristics and large in electrical resistivity. In particular, a Zn alloy having a mechanical property with an m value of 0.3 or more and a breaking elongation of 50% or more has a good superplastic property, a large electrical resistivity, and is used in a usage environment subject to magnetic field fluctuations. However, a large electrical resistance that reduces the induced current can be obtained. This is because heat generation of the magnet compact is suppressed and suitable characteristics (particularly magnetic characteristics) are obtained. Furthermore, by using a Zn alloy binder that satisfies the above requirements, a fine crystal grain can be obtained in the manufacturing process by extending the Zn alloy (particles) into the gaps between the magnet particles. This is considered to be because it can be effectively and uniformly dispersed. As a result, since a more appropriate pressure-bonding effect can be obtained, the range that can be molded by a normal press is expanded, which is excellent in that a magnet molded body with a higher density of magnet particles can be obtained. The requirements for m value and elongation at break specified above (effectively exhibiting superplastic properties) may be sufficient if they are satisfied at or below the molding temperature at which the bonded magnet compact is molded and solidified. Preferably, it is desirable that the m value and the breaking elongation requirement (requirements for effectively exhibiting superplastic properties) defined above are satisfied in the range of room temperature (temperature in a non-heated state; the same applies hereinafter) to 500 ° C. .

  The strain rate sensitivity index (m value) of the Zn alloy is not higher than the molding temperature and is not less than 0.3, preferably not less than 0.4. When the m value of the Zn alloy is less than 0.3, there is no difference from the metal Zn, the electric resistance difference with the magnet particles is small, and the electric resistance of the bonded magnet molded body that is a solidified molded body after molding is sufficient It is not preferable that the heat generation amount cannot be sufficiently suppressed. The upper limit of the m value of the Zn alloy is not particularly limited.

(Measurement method of m value)
The m value of the Zn alloy can be obtained by carrying out a test in accordance with the tensile property evaluation method for metallic superplastic materials specified in JIS H7501 (2002 edition). Since the m value of the Zn alloy is measured in a bulk state, for example, it is measured using a plate material produced in the same manner as the measurement method of elongation at break below, or a test piece obtained by punching the plate material into an appropriate size. be able to.

  The elongation at break of the Zn alloy is 50% or more, preferably 200% or more. When the elongation at break of the Zn alloy is less than 50%, there is no difference from the metal Zn, the electrical resistance difference with the magnet particles is small, and the electrical resistance of the bonded magnet molded body, which is a solidified molded body after molding, is sufficient. It is not preferable because it cannot be increased and the calorific value cannot be sufficiently suppressed. The upper limit of the elongation at break of the Zn alloy is not particularly limited.

  The Zn alloy binder contained in the bonded magnet molded body of this embodiment preferably contains a Zn alloy that exhibits a breaking elongation that is at least twice as large as that of Zn (below the molding temperature). As long as the elongation at break is at least twice as large as that of Zn, the Zn alloy is easily extended in the gaps between the magnet particles, and it is excellent in that a magnet molded body having a high density can be obtained. In addition, what is necessary is just to satisfy | fill the requirement of elongation at break 2 times or more larger than Zn prescribed | regulated above below the molding temperature at the time of shaping | molding and solidifying a bonded magnet molded object. Preferably, it is desirable to satisfy the requirement for elongation at break that is at least twice as large as Zn as defined above in the range of room temperature to 500 ° C.

(Measurement method of elongation at break)
The breaking elongation of the Zn alloy can be measured by the following method. The following method shows an example in which a ZnAl alloy (a composition of 22.6 mass% Al-77.4 mass% Zn; a composition excluding inevitable impurities; the same shall apply hereinafter) is used as the Zn alloy. In the case of an alloy other than the above or an alloy using a metal other than Al, the measurement can be performed according to the following method.

  First, a pure Al ingot and a pure Zn ingot are weighed so as to have a composition of 22.6 mass% Al-77.4 mass% Zn, and 3 kg of an alloy ingot is melted in a vacuum melting furnace. The ingot is redissolved and processed into an alloy powder by a gas atomization method using He. After the obtained powder is sieved to remove coarse particles of 50 μm or more, the powder is extruded at 450 ° C. (extrusion ratio 12.7), and further processed by swaging to a width of 50 mm and a thickness of 5 mm. .

  Next, the temperature is raised to 250 ° C. in an electric furnace, hot rolling is performed, and the final thickness is adjusted to 1.0 mm. A test piece having a parallel part width of 5 mm, a parallel part length of 25 mm, and a total length of 59 mm is taken from the steel sheet in parallel with the rolling direction as an S-type test piece specified in JIS H7501. Thereafter, the obtained test piece was kept in a salt bath at 380 ° C. (comprising potassium nitrate and sodium nitrate in a 1: 1 ratio (molar ratio)) for 30 minutes, quenched in ice water, and further brought to room temperature for 24 hours. The eutectoid decomposition is carried out by leaving it for a while.

  The test piece obtained can be subjected to a test according to the tensile property evaluation method for metallic superplastic material of JIS H7501 (2002 edition), whereby the elongation at break of the Zn alloy can be obtained.

  When measuring the above m value and elongation at break at a temperature of room temperature or higher, the hook type jig of the tensile tester is mounted on the test piece side, and both the jig part and the test piece are kept for a predetermined time of 10 minutes or more. It is possible to evaluate at an arbitrary temperature by holding it in an oil bath at a temperature and sufficiently performing the test after reaching the set temperature.

  About Zn, the elongation at break of Zn can be calculated | required by extract | collecting the same test piece from the commercially available pure Zn board of thickness 1.0mm, and using for a test.

  The content of the Zn alloy binder is preferably 1 to 30% by volume, more preferably 5 to 20% by volume, and still more preferably 10 to 20% by volume with respect to the total volume of the bonded magnet molded body. If the content of the Zn alloy binder is 30% by volume or less, the electrical specific resistance is large, heat generation of the magnet compact is suppressed, suitable characteristics (particularly magnetic characteristics) are obtained, and the magnetic characteristics of the magnet compact are impaired. There is no fear. Further, if the content of the Zn alloy binder is 20% by volume or less, the volume fraction of the magnet particles can be significantly increased as compared with the Zn alloy particles, and a good magnetic force (particularly residual magnetic flux density Br) can be obtained. it can. Further, if the content of the Zn alloy binder is 1% by volume or more, the effect as a Zn alloy binder is sufficiently exerted, the superplastic characteristics are good, the electric specific resistance is large, the heat generation of the magnet compact is suppressed, Suitable characteristics (particularly magnetic characteristics) can be obtained. Moreover, if content of Zn alloy binder is 5 volume% or more, favorable magnetic force (especially residual magnetic flux density Br) can be obtained, without impairing the magnetic characteristic of a magnet molded object. Moreover, since the compounding quantity of Zn alloy particle | grains can also be ensured enough, the Zn alloy particle can exhibit the effect excellent as a binder by extending and disperse | distributing effectively and uniformly.

  The Zn alloy binder contained in the bonded magnet molded body of the present embodiment is not limited as long as it has the above requirements, and examples thereof include alloys containing Zn and metals other than Zn, such as Al, Mg, and Cu. Is an alloy that exhibits superplasticity (superplastic alloy). Furthermore, from the viewpoint of suppressing the amount of oxygen (inevitable impurities) mixed in these superplastic alloys, superplastic alloys containing C and the like can also be used. As a superplastic alloy suitable as a Zn alloy, a ZnAl-based alloy containing Zn and Al is preferable. Such a ZnAl-based alloy composition may use a simple eutectic composition of Zn and Al so as to be easy to manufacture. However, if it is an element that does not excessively react with magnet particles and impair magnetic properties, Adjustments can be made accordingly. For example, Mg or Cu may be added for the purpose of improving the deformability, may be changed to a Zn-rich composition from the viewpoint of magnetic properties, or may be changed to an Al-rich composition from the viewpoint of economy. I do not care. Specifically, a binary ZnAl alloy, a ternary ZnAlMg alloy containing Mg, a ternary ZnAlCu alloy containing Cu, a ZnAlMgC alloy further containing C in these ternary alloys, a ZnAlCuC alloy, etc. It is done. The above-described ZnAl-based alloys (the binary and ternary Al-containing Zn alloys) exhibit superplastic behavior, so that the density can be easily improved, and at the same time, Zn and Al have fine crystal grains. And has a higher electrical resistivity than single phase pure metal. Therefore, it is possible to obtain a magnet molded body having a large electrical specific resistance while increasing the density of the magnet particles. However, the present embodiment is not limited to these. In addition, inevitable impurities may be contained in the above-described Zn alloy.

  The alloy composition of the Zn alloy binder is not limited as long as the strain rate sensitivity index (m value) specified above (below the molding temperature) is 0.3 or more and the elongation at break satisfies the requirement of 50% or more. Is not to be done. For example, taking the binary ZnAl alloy exemplified as the above-described alloy exhibiting superplasticity (superplastic alloy) as an example, the ZnAl alloy composition may be any composition that exhibits superplasticity, preferably A composition of 18 to 27 mass% Al-82 to 73 mass% Zn (a composition excluding inevitable impurities; the same shall apply hereinafter), more preferably a composition of 20 to 25 mass% Al-80 to 75 mass% Zn. Here, a binary ZnAl alloy has been described as an example, but in the binary ZnAl alloy composition, a part (preferably about 0.01 to 3 mass%) of (Zn or) Al is used as the Mg. It is possible to use a ternary alloy composition substituted with Cu, Cu, or C.

  In this embodiment, it is preferable not to include a binder composed of a polymer, particularly an organic polymer. This is because the organic polymer binder has a large proportion of about 30% of the bonded magnet molded body, but does not function as a magnet, so that the magnetic properties of the magnet molded body are deteriorated. The present embodiment is excellent in that it can prevent a decrease in magnetic properties due to an organic polymer binder because a magnet molded body can be obtained by solidification (molding) without including a polymer binder. Further, by not using a polymer binder having a low melting point, a magnet that can be used even in a higher temperature environment can be obtained. However, the present embodiment includes a case where the polymer binder is contained in a very small amount to such an extent that the magnetic properties are not deteriorated.

  Similarly, in the present embodiment, it is preferable not to include a metal binder, particularly a metal (Zn) binder having excellent formability and magnetic properties. This is because the metal binder has a problem that, as described above, the electric resistance is smaller than that of the magnet particles, the electric resistance of the bonded magnet molded body that is a solidified molded body after solidification (molding) is small, and the amount of heat generation increases. This embodiment is excellent in that a magnet molded body having a large electric resistance that reduces the induced current can be obtained even when it is used in a usage environment subject to magnetic field fluctuations by not including a metal binder. Yes. However, the present embodiment includes a case where the metal binder is included in a trace amount so that the calorific value does not increase even when the metal binder is used in a usage environment that receives a magnetic field fluctuation.

(2) Sm-Fe-N-based magnet particles Sm and Fe-containing nitrogen compound magnet particles (Sm-Fe-N-based magnet particles) usually contain a magnet phase mainly composed of Sm-Fe-N. To do. Sm-Fe-N magnet particles are promising as permanent magnets because of their excellent magnetic properties.

More specifically, as the Sm-Fe-N-based magnet particles, for example, Sm ₂ Fe ₁₇ N _x (where x is preferably 1 to 6, more preferably 1.1 to 5). Further, 1.2 to 3.8, more preferably 1.7 to 3.3, particularly preferably 2.0 to 3.0), Sm ₂ Fe ₁₇ N ₃ , (Sm _0.75 Zr _{0. 25} ) (Fe _0.7 Co _0.3 ) N _x (where x is preferably 1-6), SmFe ₁₁ TiN _x (where x is preferably 1-6), ( Sm ₈ Zr ₃ Fe ₈₄ ) ₈₅ N ₁₅ , Sm ₇ Fe ₉₃ N _x (where x is preferably 1 to 20), and the like are exemplified, but the invention is not limited thereto. More preferably, magnet particles of Sm ₂ Fe ₁₇ N _x (x = 1.7 to 3.3), more preferably Sm ₂ Fe ₁₇ N _x (x = 3.0) are desirable. This is because the anisotropic magnetic field and saturation magnetization are large and the magnetic characteristics are excellent. These Sm—Fe—N magnet particles may be used alone or in combination of two or more.

  The content of the main component (Sm-Fe-N) of the Sm-Fe-N-based magnet particle of the present embodiment is not limited as long as it contains Sm-Fe-N as a main component. It is 50 mass% or more with respect to the whole magnet particle, Preferably it is 80 mass% or more, More preferably, it is 90 mass% or more, More preferably, it is 90-99 mass%. The upper limit of the range is more preferably 99% by mass and not 100% by mass because it contains surface oxides and inevitable impurities. That is, in this embodiment, it may be 50% by mass or more, and it is possible to use 100% by mass. However, in practice, it is difficult, complicated, and high to remove surface oxides and inevitable impurities. Expensive refining (smelting) technology is required and is expensive.

  Furthermore, the rare earth magnet phase of the Sm—Fe—N-based magnet particle includes other elements in addition to the main component Sm—Fe—N, and is also included in the technical scope of the present embodiment. Examples of other elements that may be contained include, for example, Ga, Nd, Zr, Ti, Cr, Co, Zn, Mn, V, Mo, W, Si, Re, Cu, Al, Ca, B, Ni, C, La, Ce, Pr, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Th, MM, preferably B, C substituting for Co, Ni, N replacing Fe However, it is not limited to these. These may contain one kind alone or two or more kinds. These elements are introduced by replacing or inserting part of the phase structure of the magnet phase mainly composed of Sm—Fe—N.

Similarly, the Sm—Fe—N-based magnet particle may contain a rare earth magnet phase other than Sm—Fe—N. Examples of such other rare earth magnet phases include other existing rare earth magnet phases other than Sm—Fe—N. Such other existing rare earth magnet phases include, for example, Sm ₂ Fe ₁₄ B, Sm ₂ Co ₁₄ B, Sm ₂ (Fe _1-x Co _x ) ₁₄ B (where x is preferably 0 ≦ x ≦ 0). Sm ₁₅ Fe ₇₇ B ₅ , Sm ₁₅ Co ₇₇ B ₅ , Sm _11.77 Fe _82.35 B _5.88 , Sm _11.77 Co _82.35 B _5.88 , Sm _1.1 Fe ₄ B ₄ , Sm _1.1 Co ₄ B ₄ , Sm ₇ Fe ₃ B ₁₀ , Sm ₇ Co ₃ B ₁₀ , (Sm _1-x Dy _x ) ₁₅ Fe ₇₇ B ₈ (where x is preferably 0 ≦ y ≦ 0.4), (Sm _1-x Dy _x ) ₁₅ Co ₇₇ B ₈ (where x is preferably 0 ≦ y ≦ 0.4), Sm ₂ Co ₁₇ N _x (Where x is preferably 1 to 6), Sm _{1 5} (Fe _1-x Co _x ) ₇₇ B ₇ Al ₁ , Sm ₁₅ (Fe _0.80 Co _0.20 ) _77-y B ₈ Al _y (where y is preferably 0 ≦ y ≦ 5) ), (Sm _0.95 Dy _0.05 ) ₁₅ Fe _77.5 B ₇ Al _0.5 , (Sm _0.95 Dy _0.05 ) ₁₅ (Fe _0.95 Co _0.05 ) _77.5 B _{6 .5} Al _0.5 Cu _0.2 , Sm ₄ Fe ₈₀ B ₂₀ , Sm _4.5 Fe ₇₃ Co ₃ GaB ₁₈ . ₅ , Sm _5.5 Fe ₆₆ Cr ₅ Co ₅ B _18.5 , Sm ₁₀ Fe ₇₄ Co ₁₀ SiB ₅ , Sm _3.5 Fe ₇₈ B _18.5 , Sm ₄ Fe _76.5 B _18.5 , Sm ₄ Fe _77.5 B _18.5 , Sm _4.5 Fe ₇₇ B _18.5 , Sm _3.5 DyFe ₇₃ Co ₃ GaB _18.5 , Sm _4.5 Fe ₇₂ Cr ₂ Co ₃ B _18.5 , Sm _{4 .5} Fe ₇₃ V ₃ SiB _18.5 , Sm _4.5 Fe ₇₁ Cr ₃ Co ₃ B _18.5 , Sm _5.5 Fe ₆₆ Cr ₅ Co ₅ B _18.5 , SmCo ₅ , Sm ₂ Co ₁₇ , Sm _{3 Co, Sm 3 Co 9,} SmCo 2, SmCo 3, Sm 2 Co 7 , etc. SmCo alloy _{system, Sm 2 Fe 17, SmFe 2} , SmFe 3 etc. SmFe alloy system of, CeCo _{, Ce 2 Co 17, Ce 24} Co 11, CeCo 2, CeCo 3, Ce 2 Co 7, Ce 5 Co 19 such CeCo alloy _system, Nd 2 _{Fe Nd-Fe} alloy system such as _17, such as a CaCu ₅ Ca-Cu alloy system, Tb-Cu alloy system such as TbCu ₇ , Sm-Fe-Ti alloy system such as SmFe ₁₁ Ti, Th-Mn alloy system such as ThMn ₁₂ , Th-Zn alloy system such as Th ₂ Zn ₁₇ , Th ₂ Ni _{17 and} other Th—Ni alloy systems, La ₂ Fe ₁₄ B, CeFe ₁₄ B, Pr ₂ Fe ₁₄ B, Gd ₂ Fe ₁₄ B, Tb ₂ Fe ₁₄ B, Dy ₂ Fe ₁₄ B, Ho ₂ Fe _{14 B, Er 2 Fe 14 B} , Tm 2 Fe 14 B, Yb 2 Fe 14 B, Y 2 Fe 14 B, Th 2 Fe 14 B, La 2 Co 14 B, CeCo 14 B, P _{2 Co 14 B, Gd 2 Co} 14 B, Tb 2 Co 14 B, Dy 2 Co 14 B, Ho 2 Co 14 B, Er 2 Co 14 B, Tm 2 Co 14 B, Yb 2 Co 14 B, Y 2 Co ₁₄ B, Th ₂ Co ₁₄ B, YCo ₅ , LaCo ₅ , PrCo ₅ , NdCo ₅ , GdCo ₅ , TbCo ₅ , DyCo ₅ , HoCo ₅ , ErCo ₅ , TmCo ₅ , MMCo ₅ , MM _0.8 Sm _{0.2 Co 5, Sm 0.6 Gd 0.4 Co} 5, YFe 11 Ti, NdFe 11 Ti, GdFe 11 Ti, TbFe 11 Ti, DyFe 11 Ti, HoFe 11 Ti, ErFe 11 Ti, TmFe 11 Ti, LuFe 11 Ti, Pr _0.6 Sm _0.4 Co, Sm _0.6 Gd _0.4 Co ₅ , Ce (Co _0.72 Fe _0.14 Cu _0.14 ) _5.2 , Ce (Co _0.73 Fe _0.12 Cu _0.14 Ti _0.01 ) _6.5 , (Sm _0.7 Ce _0.3 ) (Co _0.72 Fe _0.16 Cu _0.12 ) ₇ , Sm (Co _0.69 Fe _0.20 Cu _0.10 Zr _0.01 ) _7.4 , Sm (Co _0.65 Fe _0.21 Cu _0.05 Zr _{0 0.02} ) _{7.67 and the} like, but are not limited thereto. These may be used alone or in combination of two or more. In addition, Sm-Fe-N-based magnet particles are inevitable components such as rare earth oxide phase (SmO ₂ phase), Fe / rare earth impurities, Fe rich phase, Fe poor phase present at the boundary of rare earth magnet phase. May contain phase and other inevitable impurities.

  The shape of the Sm—Fe—N magnet particles of the present embodiment may be any shape. For example, a spherical shape, an elliptical shape (preferably a range in which the aspect ratio (aspect ratio) of the central section parallel to the major axis direction is more than 1.0 and 10 or less), a cylindrical shape, a polygonal column (for example, a triangular prism, four Rectangular prism, pentagonal prism, hexagonal prism, ..n prismatic shape (where n is an integer of 7 or more), needle shape or rod shape (aspect ratio of the central section parallel to the long axis direction) Is preferably in the range of more than 1.0 and 10 or less.), Plate shape, disk (disk) shape, flake shape, scale shape, indeterminate shape, etc., but are not limited thereto. . Note that the rare earth magnet phase of Sm—Fe—N has a crystal structure, and can be formed into a predetermined crystal shape by crystal growth.

  The size (average particle diameter) of the Sm—Fe—N-based magnet particles may be within a range in which the effects of the present embodiment can be effectively expressed, but the smaller the coercive force is, the less 0.1 ˜15 μm is preferred. More preferably, it is 0.1-10 micrometers, More preferably, it is 0.1-8 micrometers, Most preferably, it is the range of 0.5-6 micrometers. If the average particle size of the above-mentioned magnet powder is 0.1 μm or more, it is relatively easy to handle with little influence of oxidation, and has a high density and excellent magnet properties (residual magnetic flux density and coercive force). It can be. Moreover, if the average particle diameter of the said magnet powder is 15 micrometers or less, a particle | grain will express the characteristic of a single domain particle | grain and it can be set as the magnet molded object excellent in the coercive force.

Here, the average particle diameter of the magnet particles can be measured by a laser diffraction method, as an index D _50. In addition, particle size analysis (measurement) can be performed by SEM (scanning electron microscope) observation, TEM (transmission electron microscope) observation, or the like. The magnet particles or their cross-sections may contain non-spherical powders having different aspect ratios (aspect ratios) rather than spherical or circular shapes (cross-sectional shapes). Therefore, the average particle diameter mentioned above is represented by the average value of the absolute maximum length of the cut surface shape of each magnet particle in the observation image because the shape of the magnet particle (or its cross-sectional shape) is not uniform. . The absolute maximum length means the maximum length among the distances between any two points on the outline of the magnet particle (or its cross-sectional shape). In addition to this, for example, by obtaining the crystallite diameter obtained from the half-value width of the diffraction peak of the rare earth magnet phase in X-ray diffraction or the average value of the particle diameter of the magnet particles obtained from the transmission electron microscope image. You can also. In addition, it can obtain | require similarly about the measuring method of another average particle diameter.

  The bonded magnet molded body of the present embodiment preferably contains 70 to 97% by volume of the Sm—Fe—N magnet particles. More preferably, it is 80-95 volume%, More preferably, it is the range of 80-90 volume%. If the content of the magnet particles is 70% by volume or more, the electrical specific resistance is large, the heat generation of the magnet molded body is suppressed, suitable characteristics (particularly magnetic characteristics) are obtained, and the magnetic characteristics of the magnet molded body are impaired. There is no fear. Further, if the content of the magnet particles is 80% by volume or more, the volume ratio of the magnet particles can be significantly increased as compared with Zn alloy particles, and a good magnetic force (particularly, residual magnetic flux density Br) can be obtained. it can. When the content of the magnet particles is 97% by volume or less, the superplastic characteristics are good and the electrical specific resistance is large, the heat generation of the magnet compact is suppressed, and suitable characteristics are obtained. Moreover, if content of the said magnet particle is 95 volume% or less, favorable magnetic force (especially residual magnetic flux density Br) can be obtained, without impairing the magnetic characteristic of a magnet molded object. Moreover, since the content of the Zn alloy binder can be sufficiently secured, the Zn alloy (particles) can be extended and effectively dispersed uniformly, whereby an excellent effect as a binder can be exhibited.

  The bonded magnet molded body of the present embodiment is not particularly limited as long as the magnet particles are solidified (molded) with the Zn alloy binder. Preferably, the bonded magnet molded body that is solidified (molded) has a relative density of 80% or more. This is because, when the relative density is 80% or more, the magnet molded body has a sufficient bending strength for use in electromagnetic devices such as an in-vehicle motor or an in-vehicle sensor, an actuator, and a voltage converter. The relative density is influenced by the composition of the magnet and the manufacturing stage, in particular the pressure during molding. The relative density of the bonded magnet molded body is more preferably 80% or more and less than 96.0%, further preferably 81 to 95%, and particularly preferably 82 to 94.6%. If the relative density is 96.0% or less, sufficient magnetic properties can be obtained. The relative density is obtained by using the true density obtained by calculation and the actual density obtained by measuring the size and weight of the magnet compact. The relative density is the ratio (%) of the actual density to the true density, and is calculated by dividing the actual density value by the theoretical density value and multiplying by 100.

  The bonded magnet molded body of this embodiment should have a large specific resistance, and is preferably 1.4 μΩm or more. If the specific resistance of the bonded magnet molded body is 1.4 μΩm or more, the specific resistance is larger than that of a magnet molded body including a normal rare earth magnet material, in particular, a metallic Zn binder described in Non-Patent Document 1. Heat generation due to fluctuations in the magnetic field can be reduced. From such a viewpoint, the specific resistance of the bonded magnet molded body is more preferably 1.5 μΩm or more, further preferably 2.0 μΩm or more, and particularly preferably 2.3 μΩm or more.

(II) Bond magnet molded body manufacturing method (second embodiment)
A method for producing the bonded magnet molded body of the first embodiment will be described.

  2nd Embodiment of this invention is a manufacturing method of the bonded magnet molded object which solidifies (molds) the said magnet particle using Zn alloy particle | grains which are binder materials, Comprising: The said magnet particle of the temperature of 500 degrees C or less and The mixture of the Zn alloy particles is pressure-molded at 0.8 GPa or more. By having such a configuration, a magnet molded body having the effects of the first embodiment described above can be obtained. Furthermore, since the Zn alloy extends into the gaps between the magnet particles and the Zn alloy can be effectively and uniformly dispersed, an appropriate pressure-bonding effect can be obtained. Thereby, since the range which can be shape | molded with a normal press expands, the magnet molded object which raised the density of the magnet particle more can be obtained. Hereinafter, the manufacturing method of the bonded magnet molded body of this embodiment will be described.

  The manufacturing method of the bonded magnet molding of this form has a preparatory process (S11), a warm or cold compaction molding process (S12), and a heat treatment process (S13). The preparation step (S11) is a step of preparing a mixture of the above-described Sm—Fe—N magnet particles and Zn alloy particles as a binder material, and is optional. In the warm or cold compacting step (S12), the mixture of the magnet particles and the Zn alloy particles having a temperature of 500 ° C. or lower is pressed (consolidated) in a mold with a molding surface pressure of 0.8 GPa or more. It shape | molds and the bonded magnet molded object of 1st Embodiment is obtained. In the heat treatment step (S13), the bonded magnet molded body obtained in the warm or cold compaction step (S12) is heated at a temperature of 350 to 500 ° C. for 1 to 120 minutes. The preparation step (S11) and the heat treatment step (S13) are optional steps. In this way, a bonded magnet molded body as a product is obtained.

(1) Preparation step (S11)
In the preparation step (S11), a mixture obtained by blending Sm—Fe—N-based magnet particles as raw materials and Zn alloy particles as a binder material is prepared and used for the next step (S12). Commercially available products (including custom-made products) may be used or prepared for the Sm—Fe—N magnet particles used as raw materials and the Zn alloy particles used as binder materials. Furthermore, a commercial product (including a custom-made product) of a mixture obtained by blending Sm—Fe—N-based magnetic particles and a binder material as raw materials may be used. When using a commercial product of a mixture obtained by blending Sm—Fe—N-based magnet particles and a binder material as such raw materials, a preparation step is not particularly required. When using commercial products for Sm-Fe-N magnet particles and Zn alloy particles, in the preparation step (S11), commercially available (or custom-made) Sm-Fe-N magnet particles and Zn alloy particles are blended. The prepared mixture may be prepared. Further, when preparing Sm—Fe—N-based magnet particles and / or Zn alloy particles as raw materials, in the preparation step (S11), these magnet particles and / or Zn alloy particles are prepared (magnet particle adjusting step and (Or Zn alloy grain adjustment step), a mixture obtained by blending these may be prepared (mixing step). Among these, when preparing any one of a magnet particle or Zn alloy particle, the other should just use a commercial item. Hereinafter, as the preparation step (S11), the magnet particles and Zn alloy particles are prepared (magnet particle adjustment step and Zn alloy particle adjustment step), and a mixture obtained by blending them is prepared (mixing step) as an example. To do.

(1a) Step of preparing Sm—Fe—N magnet particles by fine pulverization (magnet particle preparation step (S11a))
When preparing Sm-Fe-N-based magnet particles in this preparation step (S11a), the Sm-Fe-N-based magnet particles are finely pulverized, and Sm-Fe-N-based magnet particles having a desired size are obtained. Can be obtained. The size (average particle size) of the Sm—Fe—N-based magnet particles is the same as the size (average particle size) of the magnet particles of the first embodiment.

  Here, since the measuring method of the average particle diameter of the magnet particles can be obtained in the same manner as the method described in the first embodiment, description thereof is omitted here.

A commercial item may be used for the Sm-Fe-N magnet coarse powder, or it may be prepared by itself. The Sm-Fe-N magnet coarse powder is produced by, for example, producing SmFe alloy powder from samarium oxide and iron powder by a reduction diffusion method, and N ₂ gas, NH ₃ gas, mixed gas of N ₂ and H ₂ gas, etc. In this atmosphere, a heat treatment of 600 ° C. or lower can be used to obtain SmFeN. Moreover, you may use what nitrided the powder obtained by manufacturing a SmFe alloy by the melt | dissolution method and carrying out the coarse grinding | pulverization.

  There is no restriction | limiting in particular as a method of grind | pulverizing Sm-Fe-N type magnet coarse powder until it becomes a desired magnitude | size, A well-known grinder can be used. Preferably, a dry jet mill or a wet bead mill (wet ball mill) can be used. Although it is technically difficult to finely pulverize the dry jet mill until the average particle diameter becomes 2 μm or less, it is advantageous in that the finely pulverized magnet particles hardly contain impurities. On the other hand, the wet bead mill is preferable because the coercive force of the obtained bonded magnet molded body is high because the magnet particles can be finely pulverized to an average particle diameter of 2 μm or less. If necessary, the finely pulverized magnet particles may be classified with a mesh or the like. The particle diameter of the classified magnet particles is measured by a laser diffraction method, and further classification may be performed if necessary. Thus, magnet particles having a desired size (average particle diameter) can be obtained.

  In the case of preparing magnet particles by finely pulverizing Sm—Fe—N magnet coarse powder, the steps after the preparation step, that is, from the preparation step to the warm or cold compaction step (further heat treatment step) are not performed. It is preferable to carry out under an active atmosphere. Under an inert atmosphere means an atmosphere that does not substantially contain oxygen. Under an inert atmosphere, the performance of the magnet is related to the amount of impurities, so that it can be prevented that the amount of impurities such as oxygen increases and the magnetic properties are deteriorated. Further, when the finely pulverized Sm—Fe—N magnet particles are heated, the magnetic properties are severely deteriorated due to oxidation, and the particles can be prevented from burning.

  The inert atmosphere may be an inert gas atmosphere such as nitrogen or a rare gas. Under an inert atmosphere, the oxygen concentration is preferably 100 ppm or less, more preferably 50 ppm or less, and even more preferably 10 ppm or less. In addition, when using a commercial item as a Sm-Fe-N type | system | group magnet particle, since the magnet particle is surface-treated, it is not necessary to implement a subsequent process under inert atmosphere. When finely pulverizing Sm-Fe-N-based magnet particles to obtain Sm-Fe-N-based magnet particles, the magnet particles prepared by pulverizing are not surface-treated, and therefore, in an inert atmosphere. By implementing this, a bonded magnet molded body with better magnetic properties can be obtained.

(Sm-Fe-N magnet particles)
The Sm—Fe—N-based magnet particles prepared in this step and used as raw materials are the same as those described in the section “(2) Sm—Fe—N-based magnet particles” of the first embodiment. be able to. Therefore, the description here is omitted.

(1b) Step of preparing Zn alloy particles as a binder material (Zn alloy particle preparation step (S11b))
The method for preparing Zn alloy particles in this preparation step (S11b) is not particularly limited, and a conventionally known method for producing an alloy, a method for preparing the alloy into a desired size (pulverization, classification, etc.), etc. Can be combined as appropriate. Hereinafter, although an example of production of ZnAl alloy particles will be described as an example, this preparation step (S11b) is not limited to the production method as described above.

  An example of a method for producing ZnAl alloy particles is shown below.

  (I) First, a pure Al ingot and a pure Zn ingot are weighed so as to have a desired composition (for example, a composition of 22.6 mass% Al-77.4 mass% Zn), and a predetermined amount (for example, 3 kg) of the alloy ingot is melted. The obtained ingot is cut into strip-shaped pieces having an appropriate size (for example, 10 × 10 × 50 mm).

  In addition, a simple eutectic composition was used for the ZnAl alloy composition in this production example so that the production was easy. Adjustments can be made accordingly. For example, Mg or Cu may be added for the purpose of improving the deformability, may be changed to a Zn-rich composition from the viewpoint of magnetic properties, or may be changed to an Al-rich composition from the viewpoint of economy. I do not care. Further, C may be added for the purpose of preventing oxide formation.

  (Ii) A predetermined amount (for example, 1.5 kg) of the obtained ZnAl alloy pieces is processed into powder particles (ZnAl alloy particles) by gas atomization. First, after evacuating the inside of the chamber of the melting furnace, the inside of the chamber is replaced with an inert gas (for example, He gas), and a predetermined amount (1.5 kg) of a small piece of ZnAl alloy is melted by high-frequency induction melting. The atomizing device has a structure in which a spray chamber is provided below the melting chamber. A differential pressure is generated between the melting chamber and the spray chamber, and the molten metal alloy is moved downward by opening a stopper installed at the bottom of the melting furnace. An apparatus having an outflow structure can be used. It is processed into powder particles (ZnAl alloy particles) by spraying He gas (inert gas) on the molten metal alloy (ZnAl alloy) that has flowed out. By using He gas (inert gas) in the above, the molten metal alloy particles can be rapidly cooled, and fine particles of 20 μm or less can be easily obtained.

  (Iii) Finally, the obtained powder particles of 20 μm or less are classified with a mesh having a desired mesh size, and the particle diameter of the classified powder particles (ZnAl alloy particles) is measured by a laser diffraction method. For example, classification may be further performed. Thus, ZnAl alloy particles having a desired size (average particle diameter) can be prepared.

  When preparing Zn alloy particles in this preparation step (S11b), the steps after the preparation step, that is, the steps from the preparation step to the warm or cold compaction step (further heat treatment step) are performed in an inert atmosphere. It is preferable. Under an inert atmosphere, the performance of the magnet or alloy is related to the amount of impurities, so that it is possible to prevent the amount of impurities such as oxygen from increasing and magnetic properties from deteriorating. Furthermore, when a mixture of magnet particles and Zn composite particles is heated (pressure molding), it is possible to prevent the magnetic properties from being severely deteriorated due to oxidation and burning the particles.

  The inert atmosphere may be an inert gas atmosphere such as nitrogen or a rare gas. Under an inert atmosphere, the oxygen concentration is preferably 100 ppm or less, more preferably 50 ppm or less, and even more preferably 10 ppm or less.

(Zn alloy particles)
The Zn alloy particles that can be used in this embodiment are the same as the Zn alloy binder described in the first embodiment (especially m value and elongation at break) except that they are in the above-described particle form. Since it can do, description here is omitted. However, the characteristic part at the time of manufacture, such as a point which is a particle form, is demonstrated below (the content described in 1st Embodiment may be included in part).

  The shape of the Zn alloy particles may be any shape as long as the effects of the present invention are not impaired. That is, when a mixture of magnet particles and Zn alloy particles is subjected to pressure molding in a warm or cold consolidation process (heating), the Zn alloy particles easily extend into the gaps between the magnet particles, and the expanded Zn alloy is effective. Any shape that can be uniformly dispersed can be used. As a result, an appropriate pressure-bonding effect can be obtained, the range that can be molded by a normal press can be expanded, and a magnet molded body having a high density can be obtained. From this, the shape of the Zn alloy particles is, for example, spherical or elliptical (desirably, the aspect ratio (aspect ratio) of the central cross section parallel to the long axis direction is more than 1.0 and 10 or less) , Cylindrical shape, polygonal column (for example, triangular prism, quadrangular column, pentagonal column, hexagonal column,... N prism (where N is an integer greater than or equal to 7)), acicular or rod-shaped (long axis direction) The aspect ratio of the cross section of the central portion parallel to is preferably in the range of more than 1.0 to 10 or less.), Plate shape, disk (disk) shape, flake shape, scale shape, indefinite shape, etc. There is no limitation to these.

  The size (average particle diameter) of the Zn alloy particles may be within a range in which the effects of the present embodiment can be effectively expressed. That is, it is sufficient that the Zn alloy particles extend in the gaps between the magnet particles and the extended Zn alloy can be effectively and uniformly dispersed. As a result, an appropriate pressure-bonding effect can be obtained, the range that can be molded by a normal press can be expanded, and a magnet molded body having a high density can be obtained. From this, the average particle diameter of the Zn alloy particles is preferably in the range of 0.5 to 50 μm, more preferably 1 to 30 μm, and still more preferably 1 to 10 μm. If the average particle diameter of the Zn alloy particles is 0.5 μm or more, the influence of surface oxidation is relatively small, and it has excellent deformability, superplastic properties, and high electrical resistivity. The desired magnet molded body excellent in suitable characteristics (magnet characteristics such as coercive force, residual magnetic flux density, adhesion, and high density characteristics) can be obtained. If the average particle diameter of the Zn alloy particles is 50 μm or less, it is easy to mix with the magnet powder, and it is difficult to form aggregates. In addition, the superplastic characteristics are good and the electrical specific resistance is large, and the magnet compact generates heat. It is possible to obtain a desired magnet molding excellent in suitable characteristics (magnet characteristics such as coercive force, residual magnetic flux density, adhesion, and high density characteristics). In addition, also when using a commercial item as Zn alloy particle, the thing of the range prescribed | regulated above is preferable for the average particle diameter of Zn alloy particle.

  Here, since the measuring method of the average particle diameter of Zn alloy particles can be obtained in the same manner as the measuring method of the average particle diameter of the magnet particles described in the first embodiment, the description here is omitted.

  The size of the magnet particles (average particle size) and the size of the Zn alloy particles (average particle size) are closely related, and it is preferable that the following relationship is satisfied. That is, it is preferable that the average particle diameter Y (μm) of the Zn alloy particles satisfies the relationship of Y ≦ −5M + 60 with respect to the average particle diameter M (μm) of the magnet particles (see the slope of the straight line in FIG. 3). ), 0.5 ≦ Y ≦ −5M + 60 is more preferable. By satisfying this relationship, the Zn alloy particles having the average particle diameter Y extend into the gaps between the magnet particles having the average particle diameter M by the pressure forming in the next step, so that the Zn alloy particles are effectively interposed between the magnet particles. Can be uniformly dispersed in the voids. Therefore, by obtaining an appropriate pressure-bonding effect, the range that can be molded by a normal press is expanded, so that a magnet molded body with a higher density of magnet particles can be obtained.

(1c) Step of preparing a mixture in which the magnet particles and Zn alloy particles are blended (mixing step (S11c))
In this mixing step (S11c), a mixture is prepared by blending the above-described magnet particles with Zn alloy particles as a binder material. By blending the Zn alloy particles with the magnet particles, the Zn alloy particles extend into the gaps between the magnet particles during the warm or cold compaction molding in the next step, and the extended Zn alloy is effective. Can be uniformly dispersed. Therefore, a fine crystal grain is obtained. If the crystal grains are fine, it is possible to obtain characteristics that are excellent in superplastic characteristics and large in electrical resistivity. In particular, Zn alloy particles having a mechanical property with an m value of 0.3 or more and a breaking elongation of 50% or more are excellent in superplastic characteristics, large in electrical specific resistance, and used in a use environment that receives magnetic field fluctuations. Even so, it is possible to obtain a large electrical resistance that reduces the induced current. Thereby, the heat generation of the magnet compact is suppressed, and suitable characteristics are obtained. Furthermore, since an appropriate press-bonding effect can be obtained, the range that can be molded by a normal press is expanded, so that it is also excellent in that a magnet molded body having a higher density of magnet particles can be obtained. In addition, during the warm or cold compaction molding in the next step, the gap between the magnet particles is filled while extending with other Zn alloy particles distributed in the vicinity of a certain arbitrary Zn alloy particle. By bonding to (in contact with), an appropriate pressure-bonding effect is obtained, and moldability is improved. Therefore, the obtained magnet molding is excellent in mechanical strength. Furthermore, since an appropriate pressure-bonding effect is obtained, the range that can be molded by a normal press is expanded, so that a magnet molded body having a higher density of magnet particles can be obtained. Furthermore, since a Zn alloy (particle) binder can relieve internal stress generated during molding, a magnet molded body with few defects can be obtained. Furthermore, the magnet molded object which can be used also in a high temperature environment can be obtained by using Zn alloy particle | grains as binder material. When preparing (preparing) a mixture by blending the magnet particles with Zn alloy particles as a binder material, the magnet particles and the Zn alloy particles may be mixed with a mixer or the like until they are uniform. The Zn alloy particles (binder material of the metal bond magnet) need only be used in a relatively small amount as compared with the polymer binder in the resin bond magnet, so there is no risk of affecting the magnetic properties and causing a decrease in the magnetic properties. Also excellent in terms.

  The blending amount of the Sm—Fe—N-based magnet particles is the same as the content of the magnet particles of the first embodiment.

  The compounding amount of the Zn alloy particles is the same as the content of the Zn alloy binder of the first embodiment.

(2) Warm or cold compaction process (S12)
In the forming step (S12), the mixture of the magnet particles and the Zn alloy particles having a temperature of 500 ° C. or lower is pressed (consolidated) in a forming die with a forming surface pressure of 0.8 GPa or more, It is a process of obtaining the bonded magnet molding of the embodiment. In this embodiment, even when Sm ₂ Fe ₁₇ N ₃ alloy is used as magnet particles, there is an advantage that thermal decomposition of the magnet particles can be suppressed. In addition, since a magnet molded body is manufactured by pressurizing (consolidating) the mixture of the magnet particles and the Zn alloy particles at a high surface pressure, the magnetic characteristics that have occurred when sintering are not deteriorated. Therefore, the magnet compact which has the effect of the above-mentioned 1st Embodiment can be obtained, maintaining the outstanding magnetic characteristic of a Sm-Fe-N type magnet particle. That is, even when used in a use environment that receives magnetic field fluctuations, a large electrical resistance that reduces the induced current can be obtained. As a result, heat generation of the magnet compact can be suppressed, and a magnet compact with improved magnetic properties can be obtained.

  In the main forming step (S12), the mixture of the magnet particles and the Zn alloy particles (hereinafter also simply referred to as a mixture of magnet particles, etc.) is heated to a temperature at which the magnetic properties of 500 ° C. or less are not significantly changed, or Pressurized (consolidated) without heating. In addition, when obtaining a magnet compact having a high density (for example, a relative density of 80% or more), it can be sufficiently molded by a cold compacting method in which pressure (consolidation) molding is performed at room temperature (not heated). The warm compacting method in which pressure (consolidation) molding is performed in this state is superior in that a magnet compact can be obtained with a reduced molding surface pressure. Therefore, in this molding process, the use of the above-mentioned warm compaction method can greatly extend the life of the mold (mold) and is superior in that it is more productive and suitable for industrial production. ing. Further, in this molding process, the density of the magnet compact obtained is higher when the above-mentioned warm compaction method is used than when the compact compaction method (at room temperature) is compacted with the same molding surface pressure. Can be improved. From this point of view, when the above-described warm compaction method is used in this molding process, the temperature of the mixture such as magnet particles at the time of pressurization (consolidation) can further extend the mold life and magnetic properties due to decomposition. From the viewpoint that the lowering of the temperature can be further prevented, the temperature is more preferably in the range of 50 to 500 ° C, and further preferably in the range of 100 to 450 ° C. Especially preferably, it is the range of 100-250 degreeC. This is by using Zn alloy particles (particularly 22 mass% Al—Zn alloy) particles as a binder material, and by setting the temperature of the mixture such as magnet particles at a pressure of 0.8 GPa or more to a range of 100 to 250 ° C., Since the density of the magnet molded body is increased, an excellent superplastic phenomenon can be exhibited. Thereby, there exists an advantage which can improve the volume ratio of a magnet particle easily.

  In the main forming step (S12), it is preferable to obtain a magnet compact having a high density (for example, a relative density of 80% or more). The relative density of the magnet compact obtained in the main molding step is the same as the matter (contents) related to the relative density of the magnet compact described in the first embodiment. Therefore, the description here is omitted.

  In the main molding step (S12), a molding die suitable for the application can be selected. Therefore, if a mold having the shape of a desired magnet molded body is used, it can be used almost as it is for a product or the next process, and so-called near net shape molding with a very small processing margin becomes possible. Therefore, the processing yield is good, the manufacturing process is simplified, and this embodiment is suitable for mass production from these points. Furthermore, what is obtained in the present embodiment is a bonded magnet molded body produced only by pressure (consolidation) molding, and has less variation in magnetic properties than the conventional manufacturing method, and thus has excellent quality stability. .

  In the main forming step (S12), when the warm compaction method is used, there is no particular limitation on heating the mixture such as magnet particles to 500 ° C. or lower. The mixture such as magnet particles may be heated before being put into the mold, or may be heated together with the mold after the mixture such as magnet particles is put into the mold. In the main molding step, when the warm compaction method is used, pressurization (consolidation) may be performed in a state where the mixture of magnet particles or the like is heated to 500 ° C. or less. Preferably, a cartridge heater is inserted and installed in the mold, so that the mixture of magnet particles and the like can be heated together with the mold after the mixture of magnet particles and the like is charged into the mold. As a method for measuring the temperature of the mixture such as the magnet particles, a temperature sensor is installed in the mold and the following method can be carried out. That is, after the mold reaches a predetermined temperature, the mold temperature is maintained for about 10 minutes until the entire mixture of magnet particles reaches the same temperature, and the temperature of the mold is regarded as the temperature of the mixture of magnet particles. . In addition, heating by high frequency or the like is also possible. When the mixture such as magnet particles is heated together with the mold, there is no fear that the mixture such as magnet particles is cooled and the manufacturing process is simplified, which is preferable. When only the mixture of magnet particles and the like is heated in advance, the mixture of magnet particles and the like is heated to a predetermined temperature in an oven or the like and put into a mold. This is preferable because the production lead time is reduced. It is sufficient that the mixture of magnet particles and the like is heated to a temperature of 500 ° C. or less while being put in the mold.

  In the main forming step (S12), when the cold compaction method is used, the mixture of magnet particles and the like is put into a mold without heating the mixture of magnet particles and the following pressure (consolidation) molding is performed. Just do it.

  Pressurization (consolidation) molding is performed (solidification molding) of a mixture such as magnet particles at a pressure (molding surface pressure) of 0.8 GPa or more. If the pressure at the time of pressurization (consolidation) (molding surface pressure) is less than 0.8 GPa, it is difficult to form a magnet compact. The upper limit of the pressure (molding surface pressure) at the time of pressurization (consolidation) is not particularly limited, but if it is 5 GPa or less, it is excellent in terms of extending the life of the mold (prolonging the life). ing. From the viewpoint of further extending the mold life while obtaining a molded article having desired magnetic properties (higher density, for example, relative density of 80% or more), the pressure at the time of pressing (consolidation) molding (molding surface pressure) Preferably it is 0.8-5GPa, More preferably, it is the range of 1.5-3.5GPa. There is no restriction | limiting in particular as a method of carrying out pressurization (consolidation), What is necessary is just the method which can apply said high surface pressure to the large area which covers the metal mold | die of the magnet formation of a desired magnitude | size. Preferably, a high-output press machine used for forging can be used, and a hydraulic press machine, an electric press machine, an impact press machine, or the like can be used.

  The mold is not particularly limited as long as it can withstand a temperature of 500 ° C. or lower and a high surface pressure of 0.8 GPa or higher, and any mold can be used. Fig.1 (a) is the top view which showed typically the example of the preferable shaping | molding die, FIG.1 (b) is sectional drawing of the AA direction of Fig.1 (a). As shown in FIG. 1 (a), a molding die 10 is formed of a cemented carbide capable of withstanding high surface pressure with a cylindrical inner die 11 having a cylindrical outer shape (upper ring shape), and a cylindrical outer die. 12 is made of softer metal. As shown in FIG. 1 (b), a mixture 14 such as magnet particles is put on a square columnar lower mold 15 in the central space of the inner mold 11, and a rectangular column shape is formed on the upper part thereof. The upper mold 16 is inserted. The upper part of the upper mold 16 protrudes from the upper surfaces of the molds 11 and 12, and when the mold 10 is pressed (pressed) from the upper part by a hydraulic press, the protruding part of the upper mold 16 is pressed, A quadrangular prism shaped magnet molded body can be formed by pressurizing (consolidating) the mixture of the lower magnet particles and the like. That is, by changing the space shape of the inner mold 11, a magnet molded body having a cylindrical shape, a polygonal column shape, or the like can be formed (solidified molding). Further, as shown in FIGS. 1A and 1B, the mold is provided with through holes 13a and 13b through which the cartridge heater is passed. The entire mold is heated (or not heated) by a cartridge heater (not shown) in the through holes 13a and 13b, and the mixture 14 such as the magnet particles in the molding space is maintained at 500 ° C. or lower. Press with a hydraulic press. Further, as shown in FIG. 1A, the outer mold 12 is provided with a temperature sensor hole 17 so that the heating temperature can be monitored when the warm compaction method is used. A temperature sensor (not shown) in 17 measures the temperature of the outer mold 12. As shown in FIG. 1B, the temperature sensor hole 17 is provided at a height close to the upper surface of the mixture 14 such as magnet particles. Therefore, after leaving the heated outer mold 12 and the inner mold 11, the lower mold 15, the upper mold 16, and the mixture 14 such as magnet particles in a thermal equilibrium state, after standing for a predetermined time. The temperature indicated by the temperature sensor in the temperature sensor hole 17 can be regarded as the temperature of the mixture 14 such as magnet particles.

(3) Heat treatment step (S13)
In the heat treatment step (S13), after the above-described warm or cold compaction step (S12), the formed (solidified) magnet molded body is heated at a temperature of 350 to 500 ° C. for 1 to 120 minutes. Although the heat treatment step is not essential, it is preferable to carry out the heat treatment step because it can bring out magnetic properties close to the maximum. In addition, the Zn alloy binder that is extended and uniformly dispersed in the gaps between the magnet particles of the magnet compact increases the pressure-bonding effect by heat treatment, and acts to reduce the soft magnetic layer and defects on the surface of the magnet particles. Therefore, it is preferable to implement. Thereby, the further improvement of the magnetic characteristic of a bonded magnet molding can be performed.

  There is no restriction | limiting in particular in heat-processing a magnet molded object, What kind of method may be used if it can heat at said temperature. Preferably, the magnet compact can be heated by the same method as the warm compacting method in the warm or cold compacting step (S12). For example, in the warm compaction method of the molding step (S12), when the mold and the mixture of magnet particles are heated together with a heater installed in the mold, the same heater is used after pressurization (consolidation) molding. Can be heated. Further, the magnet molded body obtained in the molding step (S12) can be taken out from the molding die and separately put in an oven to perform the heat treatment in this step (S13). In the heat treatment step, the magnet molded body can be heated at 380 to 480 ° C. for 10 to 60 minutes. In order to obtain a high effect of the heat treatment step, it is preferable that the heat treatment temperature in this step is higher than the (heating) temperature at the time of pressure (consolidation) molding.

  According to the present embodiment, the magnet molded body that satisfies the requirements of the first embodiment obtained by the above-described manufacturing method (implementation of each process) has a residual magnetic flux density Br of 0.75 T or more and a coercive force Hc. What has 900 kA / m or more can be obtained. More preferably, the residual magnetic flux density is 0.80 T or more and the coercive force is 1100 kA / m or more. The measuring method of the residual magnetic flux density and the coercive force is measured according to the method described in the examples.

<Another aspect A of the second embodiment>
As another aspect A of the second embodiment of the manufacturing method of the bonded magnet molded body of the first embodiment, instead of the warm or cold compacting step (S12) of the second embodiment, the temperature in a magnetic field is Or a cold compacting step (S22). That is, a bonded magnet molded body as a product is obtained by the preparation step (S21), the warm compaction in magnetic field step (S22), and the heat treatment step (S23). The preparation step (S21) and the heat treatment step (S23) are the same as the preparation steps (S11) and (S13) of the second embodiment, respectively, and are optional steps. Therefore, below, it demonstrates about the warm or cold compaction forming process (S22) in a magnetic field.

(2 ') Magnetic field warm compaction step (S22)
In this molding step (S22), in a magnetic field of 6 kOe or more, a mixture such as magnet particles having a temperature of 500 ° C. or less is pressed (consolidated) in a molding mold with a molding surface pressure of 0.2 GPa or more. It is a process of obtaining the bonded magnet molding of one embodiment. The main forming step (S22) is the same as the warm or cold compacting step (S12) of the second embodiment, except that the warm or cold compacting step is performed in a magnetic field.

  In the present embodiment A, the Sm—Fe—N-based magnet particles used for the mixture such as magnet particles are preferably anisotropic. By performing warm or cold compaction molding in a magnetic field using anisotropic Sm-Fe-N-based magnet particles, the magnet particles are molded with the easy magnetization axes aligned in the magnetic field direction. Therefore, the obtained magnet compact becomes an anisotropic magnet compact having an even higher residual magnetic flux density. The applied magnetic field is more preferably 17 kOe or more. The upper limit is not particularly limited, but is preferably 25 kOe or less because the effect of aligning the easy magnetization axis is saturated.

  In order to carry out the warm or cold consolidation step (S22) in a magnetic field, there is no particular limitation as long as a magnetic field of 6 kOe or more can be provided. For example, a known magnetic field orientation device is installed around the mold, and pressurization (consolidation) molding can be performed with a magnetic field applied. As the magnetic field orientation device, a suitable one from known magnetic field orientation devices can be selected from the shape, dimensions, etc. of the desired magnet compact. As a magnetic field application method, either a method of applying a static magnetic field like an electromagnet arranged in a normal magnetic field forming apparatus or a method of applying a pulsed magnetic field using alternating current may be adopted.

  A desired bonded magnet molding is obtained as described above. Alternatively, a desired bonded magnet molded body can be obtained by performing the heat treatment step (S23) as necessary.

<Another aspect B of the second embodiment>
As still another aspect B of the second embodiment of the method of manufacturing the bonded magnet molded body of the first embodiment, instead of the warm or cold compacting step (S12) of the second embodiment, It has a preliminary compression molding step (S32) and a warm or cold compaction step (S33). The preparation step (S31) and the heat treatment step (S34) are the same as the preparation steps (S11) and (S13) of the second embodiment, respectively, and are optional steps. That is, a bonded magnet molded body as a product is obtained through the preparation step (S31), the pre-compression molding step in a magnetic field (S32), the warm consolidation molding step (S33), and the heat treatment step (S34). Therefore, hereinafter, the preliminary compression molding step (S32) in a magnetic field will be mainly described.

(2a ″) Pre-compression molding step in magnetic field (S32)
In the present aspect B, prior to the warm or cold compaction step (S33), the mixture such as magnet particles is compression-molded in a magnetic field of 6 kOe or more to obtain a magnet compact having a relative density of 30% or more. (S32) is further included. For warm or cold compaction, a high surface pressure press is used. Therefore, attaching a magnetic field orientation device to such a large device requires a wide space and may be difficult in actual use. Accordingly, a magnetic orientation machine is attached to the low surface pressure press and a pre-compression molded body having a relative density of about 30% is prepared in advance. Thereafter, the pre-compression molded body is heated or unheated, and warm or cold compaction is performed with a high surface pressure press. This is because although the number of steps increases, it may be preferable to provide a preliminary compression molding step in consideration of mass production. By performing the pre-compression molding step, the Sm—Fe—N-based magnet particles having anisotropy in the pre-compression molded body are in a state where the easy magnetization axes are aligned. Therefore, the magnet molded body obtained through the subsequent warm or cold compaction forming step (S33) is also a magnet molded body having a higher residual magnetic flux density with uniform axes of magnetization.

  In the preliminary compression molding step (S32), since it is sufficient to obtain a molded body having a relative density that does not damage the molded body during conveyance and transportation, a preliminary compression molded body having a relative density of 30% or more is formed. In the case of a pre-compression molded body having a relative density of 30% or more, Sm—Fe—N-based magnet particles having easy magnetization axes aligned in the magnetic field direction do not move, and the easy magnetization axes are maintained. . The upper limit of the relative density of the magnet compact is not particularly limited, but is 50% or less.

  There is no restriction | limiting in particular in applying a magnetic field, A press machine can be installed in a magnetic field orientation machine. As the magnetic field orientation machine, the same magnetic field orientation machine as in the other aspect A of the second embodiment described above can be used. Further, the press machine is not particularly limited, and any press machine can be used as long as it can obtain a pre-compression molded body of a mixture of magnet particles having a relative density of 30% or more. For example, a hydraulic press machine or an electric press machine can be used, but a press machine having a lower surface pressure can be used than a press machine used in a warm or cold compaction process.

  The obtained pre-compression molded body is pressed (consolidated) in the next warm or cold compaction process (S33) in the same manner as the warm or cold compaction process (S12) of the second embodiment. Mold. Furthermore, a bonded magnet molded body can be obtained by performing the heat treatment step (S34) in the same manner as the heat treatment step (S13) of the second embodiment, if necessary.

(III) Use of bonded magnet molded body (third embodiment)
As an application of the bonded magnet molded body of this embodiment, an electromagnetic device using the magnet molded body can be cited. According to the bonded magnet molded body of this embodiment, since it does not contain a resin, it can be used at a high temperature, and a magnet molded body with low heat generation can be obtained even in a use environment with a magnetic field fluctuation. This is because when used in a device, an electromagnetic device that is safe and has low loss can be obtained. From this point of view, examples of the electromagnetic device using the bonded magnet molded body of the present embodiment include an in-vehicle motor, an in-vehicle sensor, an actuator, and a voltage conversion device, but are not limited thereto. This is also because these on-vehicle motors and the like can obtain a magnet molded body with low heat generation even in a use environment with magnetic field fluctuations, and can provide a safe on-vehicle motor with low loss. Hereinafter, a magnet motor will be described as an example of an electromagnetic device using the bonded magnet molded body of the present embodiment.

  FIG. 2A is a schematic cross-sectional view schematically showing a rotor structure of a surface magnet type synchronous motor (SMP or SPMSM). FIG. 2B is a schematic cross-sectional view schematically showing a rotor structure of an embedded magnet type synchronous motor (IMP or IPMSM). In the surface magnet type synchronous motor 40a shown in FIG. 2A, the bonded magnet molded body (simply referred to as a magnet) 41 of this embodiment is directly assembled (attached) to the rotor 43 for the surface magnet type synchronous motor. is there. In the surface magnet type synchronous motor 40a, the magnet 41 molded and solidified to a desired size (further cut if necessary) is assembled (attached) to the surface magnet type synchronous motor 40a. By magnetizing the magnet 41, the surface magnet type synchronous motor 40a can be obtained. This can be said to be superior to the embedded magnet type synchronous motor 40b. In particular, the magnet 41 is excellent in that it is easy to use without peeling off from the rotor 43 even when it is rotated at a high speed by centrifugal force. On the other hand, in the embedded magnet type synchronous motor 40b shown in FIG. 2B, the bonded magnet molded body (simply referred to as a magnet) 45 of this embodiment is formed in the embedded groove formed in the rotor 47 for the embedded magnet type synchronous motor. It is fixed by press-fitting (insertion). In the embedded magnet type synchronous motor 40b, first, the one that is molded and solidified (further cut if necessary) to the same shape and thickness as the embedded groove (illustrated figure) is used. In this case, the shape of the magnet 45 is a flat plate, and molding, solidification or cutting of the magnet 45 forms a molded body at the time of manufacturing the magnet 41 on the curved surface, or the surface on which the magnet 41 itself needs to be cut. It is excellent in that it is relatively easy compared to the magnet type synchronous motor 40a. In addition, this embodiment is not restrict | limited to only the specific motor demonstrated above, It can apply to the electromagnetic device of a wide field | area. That is, a capstan motor for audio equipment, a speaker, headphones, a CD pickup, a camera hoisting motor, a focusing actuator, a video actuator and the like, which uses an Sm-Fe-N based bonded magnet molded body. , Zoom motors, focus motors, capstan motors, DVD and Blu-ray optical pickups, air conditioning compressors, outdoor unit fan motors, electric razor motors, etc .; voice coil motors, spindle motors, CD- Computer peripherals and OA equipment such as ROM, CD-R optical pickup, stepping motor, plotter, printer actuator, dot printer print head, copier rotation sensor, clock stepping motor, various meters, pagers, portable Measurements for vibration motors for phones (including personal digital assistants), motors for driving recorder pens, accelerators, undulators for synchrotron radiation, polarizing magnets, ion sources, various plasma sources for semiconductor manufacturing equipment, for electronic polarization, and for magnetic flaw detection bias , Communication, other precision instrument fields; permanent magnet type MRI, electrocardiograph, electroencephalograph, dental drill motor, tooth fixing magnet, magnetic necklace, etc .; medical field; AC servo motor, synchronous motor, brake, clutch, torque FA fields such as couplers, linear motors for conveyance, and reed switches; retarders, ignition coil transformers, ABS sensors, rotation, position detection sensors, suspension control sensors, door lock actuators, ISCV actuators, electric vehicle drive motors, hybrid vehicle drives Motor, fuel cell Car drive motors, brushless DC motors, AC servo motors, AC induction (induction) motors, power steering, car air conditioners, car navigation optical pickups, etc. That's fine. However, the use in which the bonded magnet molded body of the present embodiment is used is not limited to the above-mentioned only a part of products (parts), and an Sm—Fe—N based bonded magnet molded body is currently used. It can be applied to all uses.

  Hereinafter, although this embodiment is concretely demonstrated through an Example, this embodiment is not limited to the following Examples.

(1) Preparation step (S11)
(1a) Magnet particle preparation step (S11a)
As the Sm—Fe—N-based magnet particles used as a raw material, one was a commercially available Sm ₂ F ₁₇ N ₃ alloy magnet particle (manufactured by Nichia Corporation). The average particle diameter was measured by a laser diffraction method. It was 2 μm using D ₅₀ as an index. This is magnet particle (1).

On the other hand, Sm—Fe—N magnet particles having different particle diameters were prepared by the following method. A commercial product (manufactured by Nichia Corporation) of an Sm—Fe alloy after nitriding with a particle size of about 30 μm produced by a diffusion reduction method is pulverized with a wet ball mill, and Sm ₂ F having a different particle size. processed (prepared) to the magnet particles ₁₇ N ₃ alloy. IPA (isopropyl alcohol) was used as the solvent. After pulverization for a certain time, pulverization is continued while confirming the particle diameter by SEM observation. Finally, the average particle diameter after pulverization is measured by a laser diffraction method and pulverized until D ₅₀ reaches 5 μm. Diameter magnet particles were obtained. This is designated as magnet particle (2). Similarly, the average particle diameter after pulverization was measured by a laser diffraction method, and pulverized until D ₅₀ became 10 μm to obtain magnet particles. This is designated as magnet particle (3).

(1b) Zn alloy particle preparation step (S11b)
ZnAl alloy particles as a binder material were prepared by the following method.

  First, a pure Al ingot and a pure Zn ingot were weighed so as to have a composition of 22.6 mass% Al-77.4 mass% Zn, and 3 kg of an alloy ingot was melted in a vacuum melting furnace. The obtained ingot was cut into strips of 10 × 10 × 50 mm. As the ZnAl alloy composition, a simple eutectic composition was used so that the production was easy.

  The obtained 1.5 kg of a small piece of ZnAl alloy was processed into powder (ZnAl alloy particles) by gas atomization. Specifically, after evacuating the chamber of the melting furnace, the inside of the chamber was replaced with He gas, and 1.5 kg of a small piece of ZnAl alloy was melted by high frequency induction melting. The atomizing device has a structure in which a spray chamber is provided below the melting chamber. A differential pressure is generated between the melting chamber and the spray chamber, and the molten metal flows downward by opening a stopper installed at the bottom of the melting furnace. A structural device was used. It was processed into powder particles (ZnAl alloy particles) by spraying He gas on the outflowing molten metal.

Here, by using He gas, the molten metal particles can be rapidly cooled, and fine particles of 20 μm or less could be easily obtained. The obtained powder (ZnAl alloy particles) was classified with a mesh, and the classified particle diameter was measured by a laser diffraction method. By this classification and measurement operation, the particles were classified until the average particle diameter D ₅₀ was 10, 26, 38, 49, and ₆₀ μm, and five types of ZnAl alloy particles having different average particle diameters D ₅₀ were obtained. And ZnAl alloy particles in order average particle diameter _{D 50} is less (1) to (5).

  Using the obtained ZnAl alloy particles, the strain rate sensitivity index (m value) and the elongation at break (in the bulk state) were measured at the molding temperature or lower (measurement temperature 200 ° C.) by the method specified above. As a result, the m value of the ZnAl alloy particles was 3.3, and the elongation at break was 600%. Since the ZnAl alloys (1) to (5) have the same alloy composition, the m value and the elongation at break of the ZnAl alloy particles (1) to (5) were all the same value.

(1b ′) Preparation of Zn Particles Commercially available Zn particles (manufactured by Honjo Chemical Co., Ltd.) were used as metal particles as a binder material for use in comparative examples. The average particle diameter _{D 50} of the Zn particles was 3 [mu] m.

(1c) Mixing step (S11c)
The magnet particles obtained in the step (S11a) and the ZnAl alloy particles (or Zn particles) obtained in the step (S11b) are mixed at a ratio shown in Table 1 below, and the magnet particles and Zn alloy particles (or Zn) are mixed. Particles) (a mixture of magnet particles, etc.).

  Here, the composition of the mixture such as magnet particles was mixed so that the blending amount (concentration) of the Zn alloy was 3.5, 5, 10, 20, and 25 volume%. Similarly, it mixed so that the compounding quantity (concentration) of Zn particle might be 5, 10, and 20 volume%.

(2) Warm or cold compaction process (S12)
The above mixture of magnet particles and the like at a temperature of 500 ° C. or lower was pressure-molded (solidified) with a pressure (molding surface pressure) of 0.98 GPa or higher with a warm press to obtain a bonded magnet molded body.

  Specifically, 2.6 g of the above mixture of magnet particles and the like are weighed and filled into a cemented carbide die having a cross-sectional shape of a molding press of 7 × 7 mm, and the predetermined molding shown in Table 1 for each of the experimental example and the comparative example. Hold at temperature for 10 minutes. After the mixture of the magnet particles or the like has sufficiently reached the warm or cold forming temperature, the forming pressure (molding surface pressure) shown in the following examples or comparative examples is loaded using a warm press machine, respectively. Holding for 2 seconds, pressurization (consolidation) molding (solidification molding) was performed. The magnet moldings of the experimental example and the comparative example were obtained through the above-described steps. In Comparative Examples 1 to 6, molding was impossible.

  Here, the molding pressure was 2.94 GPa and 0.98 GPa, and the warm molding temperature was adjusted by winding a sheet type heater with electric resistance around the mold and heating.

(Experimental example 1)
With an average particle diameter _{D 50} of 2μm magnet particles (1), the average particle diameter _{D 50} of 10μm of ZnAl particles (1), the magnet particles (1): ZnAl particles (1) = 95: 5 (vol% ) To obtain a mixture of magnet particles and the like. A mixture of magnet particles and the like at a temperature of 200 ° C. was subjected to heat and pressure molding at a pressure of 2.94 GPa with a warm press to obtain a bonded magnet molded body. In Experimental Example 1, the average particle diameter Y (μm) of the ZnAl alloy particles satisfies the relationship of Y ≦ −5M + 60 with respect to the average particle diameter M (μm) of the magnet particles.

(Experimental example 2)
ZnAl instead particle (1), the average particle diameter _{D 50} except for using the ZnAl particles of 26 .mu.m (2), and performs the same operation as in Experimental Example 1, to obtain a bonded magnet molding. Similar to Experimental Example 1, this Experimental Example 2 satisfies the relationship of Y ≦ −5M + 60.

(Experimental example 3)
ZnAl instead particle (1), the average particle diameter _{D 50} except for using the ZnAl particles of 49 .mu.m (4), and performs the same operation as in Experimental Example 1, to obtain a bonded magnet molding. Similar to Experimental Example 1, this Experimental Example 3 satisfies the relationship of Y ≦ −5M + 60.

(Experimental example 4)
Instead of the magnet particles (1), the average particle diameter D ₅₀ except for using 5μm magnet particles (2) was performed in the same manner as Experimental Example 1, to obtain a bonded magnet molding. Similar to Experimental Example 1, this Experimental Example 4 satisfies the relationship of Y ≦ −5M + 60.

(Experimental example 5)
Instead of the magnet particles (1), the average particle diameter _{D 50} using 5μm magnet particles (2), in place of the ZnAl particles (1), the average particle diameter _{D 50} was used ZnAl particles of 26 .mu.m (2) Except for the above, the same operation as in Experimental Example 1 was performed to obtain a bonded magnet molded body. Similar to Experimental Example 1, this Experimental Example 5 satisfies the relationship of Y ≦ −5M + 60.

(Experimental example 6)
Instead of the magnet particles (1), the average particle diameter D ₅₀ except for using the 10μm magnet particles (3) was performed in the same manner as Experimental Example 1, to obtain a bonded magnet molding. In Experimental Example 6, as in Experimental Example 1, the relationship of Y ≦ −5M + 60 is satisfied.

(Comparative Example 1)
ZnAl instead particle (1), the average particle diameter _{D 50} except for using the 60μm of ZnAl particles (5) have been performed in the same manner as Experimental Example 1, was not able to form a magnet molding. Molding was impossible. Unlike the experimental example 1, the comparative example 1 does not satisfy the relationship of Y ≦ −5M + 60.

(Comparative Example 2)
Instead of the magnet particles (1), the average particle diameter _{D 50} using 5μm magnet particles (2), in place of the ZnAl particles (1), the average particle diameter _{D 50} was used ZnAl particles of 49 .mu.m (4) Except for the above, the same operation as in Experimental Example 1 was performed, but a magnet molded body could not be formed. Molding was impossible. Even in this comparative example 2, unlike the experimental example 1, the relationship of Y ≦ −5M + 60 is not satisfied.

(Comparative Example 3)
Instead of the magnet particles (1), the average particle diameter _{D 50} using 5μm magnet particles (2), in place of the ZnAl particles (1), the average particle diameter _{D 50} was used 60μm of ZnAl particles (5) Except for the above, the same operation as in Experimental Example 1 was performed, but a magnet molded body could not be formed. Molding was impossible. Even in this comparative example 3, unlike the experimental example 1, the relationship of Y ≦ −5M + 60 is not satisfied.

(Comparative Example 4)
Instead of the magnet particles (1), the average particle diameter _{D 50} with 10μm of the magnet particles (3), in place of the ZnAl particles (1), the average particle diameter _{D 50} was used ZnAl particles of 26 .mu.m (2) Except for the above, the same operation as in Experimental Example 1 was performed, but a magnet molded body could not be formed. Molding was impossible. Even in this comparative example 4, unlike the experimental example 1, the relationship of Y ≦ −5M + 60 is not satisfied.

(Comparative Example 5)
Instead of the magnet particles (1), the average particle diameter _{D 50} with 10μm of the magnet particles (3), in place of the ZnAl particles (1), the average particle diameter _{D 50} was used ZnAl particles of 38 [mu] m (3) Except for the above, the same operation as in Experimental Example 1 was performed, but a magnet molded body could not be formed. Molding was impossible. Even in this comparative example 5, unlike the experimental example 1, the relationship of Y ≦ −5M + 60 is not satisfied.

(Experimental example 7)
The same operation as in Experimental Example 1 was performed except that the ratio of the magnet particles (1) to the ZnAl particles (1) was changed to the ratio of magnet particles (1): ZnAl particles (1) = 90: 10 (volume%). As a result, a bonded magnet molded body was obtained.

(Experimental example 8)
The same operation as in Experimental Example 1 was performed except that the ratio of the magnet particles (1) to the ZnAl particles (1) was changed to the ratio of magnet particles (1): ZnAl particles (1) = 80: 20 (volume%). As a result, a bonded magnet molded body was obtained.

(Experimental example 9)
The ratio of the magnet particles (1) to the ZnAl particles (1) is set to a ratio of magnet particles (1): ZnAl particles (1) = 90: 10 (volume%), and the molding pressure is 2.94 GPa and 0.98 GPa. Performed the same operation as Experimental Example 1 to obtain a bonded magnet molded body.

(Experimental example 10)
The ratio of the magnet particles (1) to the ZnAl particles (1) is set to a ratio of magnet particles (1): ZnAl particles (1) = 90: 10 (volume%), and the molding temperature is set to 200 ° C. The same operation as in Experimental Example 1 was performed to obtain a bonded magnet molded body.

(Experimental example 11)
The ratio of the magnet particles (1) to the ZnAl particles (1) is set to the ratio of magnet particles (1): ZnAl particles (1) = 90: 10 (volume%), and the (warm) molding temperature is 200 ° C. Except that the temperature was set to ° C. (cold forming temperature), the same operation as in Experimental Example 1 was performed to obtain a bonded magnet molded body.

(Experimental example 12)
Experimental Example 1 except that the ratio of the magnet particles (1) to the ZnAl particles (1) was changed to the ratio of magnet particles (1): ZnAl particles (1) = 96.5: 3.5 (volume%). Thus, a bonded magnet molded body was obtained.

(Experimental example 13)
The same operation as in Experimental Example 1 was performed except that the ratio of the magnet particles (1) to the ZnAl particles (1) was changed to the ratio of magnet particles (1): ZnAl particles (1) = 75: 25 (volume%). As a result, a bonded magnet molded body was obtained.

(Comparative Example 6)
ZnAl instead particle (1), the average particle diameter D ₅₀ except for using Zn particles 3 [mu] m, was carried in the same manner as Experimental Example 1, was not able to form a magnet molding. Molding was impossible.

(Comparative Example 7)
ZnAl instead particle (1), by using Zn particles having an average particle diameter _{D 50} of 3 [mu] m, the proportion of the magnet particles (1) and Zn particles, magnetic particles (1): Zn particles = 90: 10 (vol%) Except for the ratio, the same operation as in Experimental Example 1 was performed to obtain a bonded magnet molded body.

(Comparative Example 8)
ZnAl instead particle (1), by using Zn particles having an average particle diameter _{D 50} of 3 [mu] m, the proportion of the magnet particles (1) and Zn particles, magnetic particles (1): Zn particles = 80: 20 (vol%) Except for the ratio, the same operation as in Experimental Example 1 was performed to obtain a bonded magnet molded body.

(Evaluation)
About the obtained bonded magnet molded object, the electrical specific resistance was measured with the 4-probe method, and the residual magnetic flux density (Br) and the coercive force (Hc) were measured with the BH tracer. For the magnetic properties (Br, Hc), the measured value of Comparative Example 7 in which the ratio of Zn particles was 10% by volume was set to 100, and the relative value to the measured value was obtained. The results of electrical resistance and magnetic properties are summarized in Table 1 below.

  From the results in Table 1, Examples 1 to 13 can easily obtain a magnet molded body having a large specific resistance as compared with Comparative Examples 7 and 8 using a metal Zn binder. When the specific resistance is doubled, the amount of heat generation can be reduced to about ¼, and it has been confirmed that a magnet molded body with a small amount of heat generation can be obtained. That is, since the ZnAl alloy effectively exhibits superplastic behavior, the density can be easily improved, and at the same time, a composite structure in which Zn and Al have fine crystal grains is formed, and a single-phase pure metal (Zn binder) ) Higher electrical resistivity. Therefore, it was confirmed that a magnet molded body having a large electrical specific resistance can be obtained while increasing the density of the magnet particles. In addition, in the magnetic characteristics, Br of Examples 1 to 13 can be held substantially equal to or higher than those of Comparative Examples 7 and 8 using the metal Zn binder, and Hc is also held to be substantially equal or slightly lower. I understood that it was made.

  In addition, with respect to Experimental Examples 1 to 6 and Comparative Examples 1 to 5 in which the proportion of ZnAl alloy particles is 5% by volume, the range of molding by the average particle diameter of magnet particles and ZnAl alloy particles (moldable or unmoldable) is illustrated. 3 shows. As shown in FIG. 3, the average particle diameter Y (μm) of the Zn alloy particles is determined based on the slope of the straight line in the figure as to whether molding is possible (marked with ○) or molding is impossible (deformation occurs; × mark). It was confirmed that the relationship of Y ≦ −5M + 60 can be established with respect to the average particle diameter M (μm) of the particles.

  As shown in FIG. 3, Comparative Examples 1 to 5 do not exhibit a bonded magnet molded body (become out of shape and cannot be molded), and thus have no moldability (cannot be solidified). It does not satisfy the requirement of “solidified and molded” of the bonded magnet molded body and the manufacturing method thereof of the invention. Therefore, since it does not correspond to the bonded magnet molding of this invention and its manufacturing method, it is set as Comparative Examples 1-5.

  With respect to Experimental Examples 1, 7, 8 and Comparative Examples 6 to 8 in which the average particle diameter of ZnAl alloy particles is 10 μm and the average particle diameter of Zn particles is 3 μm, the moldability of ZnAl alloy and metal Zn as a binder is shown. The difference (moldable or not moldable) is shown in FIG. As shown in FIG. 4, it is formable if the proportion of ZnAl alloy particles is in the range of 5 to 20% by volume, which can be formed (circle mark) or cannot be formed (deforms the shape; x mark). I can confirm that. On the other hand, when the proportion of Zn particles is small (5% by volume), a bonded magnet molded body is not formed (the shape is lost and cannot be molded), and thus it does not have moldability (cannot be solidified). Was confirmed. In other words, in the ZnAl alloy particles, the ZnAl alloy extends in the gaps between the magnet particles, and the ZnAl alloy can be effectively and uniformly dispersed. Enlarge (the range that can be formed with a normal press is increased). As a result, it can be said that a magnet molded body having a large electrical specific resistance can be obtained while increasing the density of the magnet particles.

For Experimental Examples 1, 7, 8 and Comparative Examples 7-8, in which the average particle diameter of ZnAl alloy particles is 10 μm and the average particle diameter of Zn particles is 3 μm, the ratio (volume%) of ZnAl alloy binder or Zn binder, The relationship of the (electrical) specific resistance of the magnet compact is shown in FIG. As shown in FIG. 5, since the ZnAl alloy exhibits superplastic behavior, the density can be easily improved, and at the same time, a composite structure in which Zn and Al have fine crystal grains is formed. Since it has a higher electrical resistivity than (Zn binder), it was confirmed that a magnet molded product having a large electrical resistivity could be obtained (while increasing the density of the magnet particles). As a result, the magnet molded body of the present experimental example using the ZnAl alloy binder has a larger specific resistance than the magnet molded body of the comparative example using the existing single-phase pure metal (Zn binder). It can be said that heat generation due to magnetic field fluctuation can be reduced.
10 Mold,
11 Inner mold,
12 Outer mold,
13a, 13b through holes,
14 A mixture of magnet particles,
15 Lower mold,
16 Upper mold,
17 Hole for temperature sensor.

Claims (10)

  It contains a Zn alloy having a strain rate sensitivity index (m value) of 0.3 or more and a breaking elongation of 50% or more as a binder, and nitrogen compound magnet particles containing Sm and Fe are solidified by the binder. A bonded magnet molded product.   The bonded magnet molded body according to claim 1, wherein the Zn alloy exhibits an elongation at break that is at least twice as large as that of Zn.   The bonded magnet molded body according to claim 1, wherein the magnet particles are contained in an amount of 80 to 95% by volume.   The bonded magnet molded body according to any one of claims 1 to 3, wherein the Zn alloy is a ZnAl-based alloy.   Specific resistance is 1.5 microhmm or more, The bonded magnet molded object of any one of Claims 1-4 characterized by the above-mentioned. A method for producing a bonded magnet molded body in which the magnet particles are solidified using Zn alloy particles as a binder material,
The bonded magnet molded body according to any one of claims 1 to 5, wherein a mixture of the magnet particles and the Zn alloy particles at a temperature of 500 ° C or lower is pressure-molded at 0.8 GPa or more. Production method.   The method for producing a bonded magnet molded body according to claim 6, wherein the temperature of the mixture during the pressure molding is in a range of 100 ° C or higher and 250 ° C or lower.   The average particle diameter Y (μm) of the Zn alloy particles satisfies a relationship of Y ≦ −5M + 60 with respect to the average particle diameter M (μm) of the magnet particles. A method for producing a bonded magnet molded body.   The electromagnetic device using the bonded magnet molding in any one of Claims 1-5.   The electromagnetic device according to claim 9, wherein the electromagnetic device is an in-vehicle motor, an in-vehicle sensor, an actuator, or a voltage conversion device.