JP2013128018A - Exchange spring magnet and manufacturing method therefor - Google Patents

Abstract

An exchange spring magnet having a uniform composite nanostructure and an excellent coercive force and residual magnetic flux density, and a method for producing the exchange spring magnet are provided.
An exchange-spring magnet according to the present invention, a Fe nanoparticles with desired particle diameter, provided around the Fe nanoparticles, and SmCo phase consisting SmCo _5, around the SmCo phase A core / shell particle having a particle diameter of 10 to 100 nm and having a composite structure of core / shell particles.
[Selection] Figure 1

Description

  The present invention relates to an exchange spring magnet and a method for producing an exchange spring magnet.

  The exchange spring magnet is a magnet in which a soft magnetic phase such as Fe and a hard magnetic phase such as SmCo are dispersed in nano size in the same magnet. This exchange spring magnet is a new type of permanent magnet that has both a high magnetization of soft magnetism and a high coercivity of hard magnetism at the same time by magnetic exchange coupling acting between both phases. This exchange spring magnet is theoretically proposed as having the possibility of significantly exceeding the magnetic properties of conventional sintered magnets, and thus is expected to be put to practical use.

  Generally, the SmCo-based exchange spring magnet is manufactured using a liquid rapid solidification method or a solution synthesis method. In the liquid rapid solidification method, a molten metal alloy is rapidly cooled to obtain a composite nanostructure of Fe and SmCo. Although this liquid rapid solidification method is excellent in industrial properties, it is difficult to obtain a composite nanostructure having the intended composition and crystal grain size due to the limitation of the alloy composition, and an exchange spring magnet having sufficient magnetic properties is obtained. Not obtained.

On the other hand, in the solution synthesis method, for example, a metal complex such as Sm (acac) ₃ , Co (acac) ₃ is reacted in an organic solvent to produce Fe and SmCo nanoparticles, which are combined to form an exchange spring magnet. (See, for example, Patent Documents 1 to 4 below). By using such a solution synthesis method, it is possible to obtain nanoparticles having a desired composition and crystal grain size.

JP 2007-194463 A JP 2008-300797 A JP 2010-13713 A JP 2010-212501 A

  However, the solution synthesis method has a problem that although nanoparticles having a target composition and crystal grain size can be obtained, uniform mixing is difficult and a target composite nanostructure cannot be obtained. For this reason, when the solution synthesis method disclosed in Patent Documents 1 to 4 is used, an exchange spring magnet having sufficient magnetic properties cannot be obtained.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is an exchange spring magnet having a uniform composite nanostructure and having excellent coercive force and residual magnetic flux density. And it is providing the manufacturing method of an exchange spring magnet.

In order to solve the above-described problems, according to an aspect of the present invention, Fe nanoparticles having a predetermined particle size, an Sm-Co phase provided around the Fe nanoparticles and made of SmCo _5, and the Sm An exchange spring magnet comprising a core / shell particle having a particle diameter of 10 to 100 nm and having a structure in which the core / shell particle is combined is provided. .

  According to this configuration, core / shell particles in which the Sm—Co phase is formed around the Fe core and the nonmagnetic film is formed around the Sm—Co phase are formed. By compositing the core / shell particles (compositing), an exchange spring magnet in which Sm—CO phases and Fe are dispersed alternately can be obtained. In such an exchange spring magnet, since the Fe core is covered with the Sm—Co phase and the Sm—Co phase is divided by the nonmagnetic film, the coercive force and the residual magnetic flux density can be improved.

  The nonmagnetic film may have a thickness of 1 to 5 nm. By forming such a nonmagnetic film, the coercive force and the residual magnetic flux density can be further improved.

The nonmagnetic film may be made of samarium oxide or carbon containing Sm ₂ O ₃ as a main component. By forming such a nonmagnetic film, the coercive force and the residual magnetic flux density can be further improved.

  The Sm—Co phase in the core / shell particles may be 30 to 50% by volume with respect to the volume of the core / shell particles. By forming such an Sm—Co phase, it is possible to prevent contact between Fe cores.

  The Fe nanoparticles may have a particle size of 5 to 50 nm. It becomes possible to further improve a coercive force and a residual magnetic flux density because the particle size of Fe nanoparticles becomes such a size.

In order to solve the above-described problem, according to another aspect of the present invention, a Fe complex containing Fe and a Co complex containing Co are reacted in a predetermined organic solvent to obtain a Co / Fe core / shell. A step of generating particles, a step of reacting the generated Co / Fe core / shell particles with an Sm complex containing Sm in a predetermined organic solvent, and generating Sm ₂ O ₃ / Co / Fe particles; the generated said _Sm 2 _O 3 / Co / Fe particles was heat-treated at a predetermined temperature, and generating an SmCo ₅ / Fe core / shell particles, the generated surface of the SmCo ₅ / Fe core / shell particles A step of forming a nonmagnetic film, and a step of sintering the SmCo ₅ / Fe core / shell particles produced from the nonmagnetic film to form a composite. The SmCo _{5 having the} nonmagnetic film formed thereon A method for producing an exchange spring magnet having a particle diameter of / Fe core / shell particles of 10 to 100 nm is provided.

  According to such a configuration, it is possible to realize a core / shell structure in which an Sm—Co phase is formed around the Fe core and a nonmagnetic film is formed around the Sm—Co phase. By compounding the structure (compositing), an exchange spring magnet in which Sm—CO phases and Fe are dispersed alternately can be obtained. In such an exchange spring magnet, since the Fe core is covered with the Sm—Co phase and the Sm—Co phase is divided by the nonmagnetic film, the coercive force and the residual magnetic flux density can be improved.

The volume fraction of SmCo ₅ in the SmCo ₅ / Fe core / shell particles, the volume of the SmCo ₅ / Fe core / shell particles may be 30-50%.

The film thickness of the nonmagnetic film formed on the SmCo ₅ / Fe core / shell particles may be 1 to 5 nm.

The nonmagnetic film may be made of samarium oxide or carbon containing Sm ₂ O ₃ as a main component.

The particle size of Fe in the SmCo ₅ / Fe core / shell particles may be 5 to 50 nm.

  As described above, according to the present invention, a uniform composite nanostructure in which Sm—CO phase and Fe are dispersed alternately is formed, and the Sm—Co phase is separated by the nonmagnetic film. The coercive force and residual magnetic flux density of the exchange spring magnet can be improved.

It is explanatory drawing for demonstrating the exchange spring magnet which concerns on the 1st Embodiment of this invention. It is the flowchart which showed an example of the flow of the manufacturing method of the exchange spring magnet which concerns on the embodiment.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

(First embodiment)
As shown in Patent Document 1 to Patent Document 4 described above, an exchange spring comprising Co nanoparticles or Fe nanoparticles and SmCo ₅ particles using a solution synthesis method, and comprising Co or Fe particles and SmCo ₅ particles A method of manufacturing a magnet is provided. These methods are methods for producing an exchange spring magnet by mixing particles, but it is difficult to form a uniform composite nanostructure, and an exchange spring magnet having sufficient magnetic properties is produced. It was difficult.

In the method for manufacturing an exchange spring magnet according to the first embodiment of the present invention described below, core / shell particles in which an SmCo ₅ phase and a nonmagnetic film are formed around Fe nanoparticles are manufactured. Then, the exchange spring magnet is manufactured by compositing the core / shell particles. The exchange spring magnet thus obtained has a microstructure different from the conventional structure in which particles having a core / shell structure are combined, has a uniform composite nanostructure, and has excellent magnetic properties. (High coercive force and high residual magnetic flux density).

  Below, the manufacturing method of the exchange spring magnet and exchange spring magnet which concern on this embodiment is demonstrated in detail.

<About the configuration of the replacement spring magnet>
First, the configuration of the exchange spring magnet according to the present embodiment will be described in detail with reference to FIG. FIG. 1 is an explanatory diagram for explaining an exchange spring magnet according to the present embodiment.

  The exchange spring magnet according to the present embodiment is formed using core / shell particles 10 as shown on the left side of FIG. The core / shell particle 10 includes an Fe nanoparticle 11, an Sm—Co phase 13 provided around the Fe nanoparticle 11, and a nonmagnetic film 15 provided around the Sm—Co phase. ing. In the core / shell particle 10, the Fe nanoparticle 11 functions as a soft magnetic phase, and the Sm—Co phase 13 functions as a hard magnetic phase.

  The Fe nanoparticles 11 are formed using α-Fe having a predetermined crystal grain size. The crystal grain size of the Fe nanoparticles 11 is preferably 5 nm to 50 nm, and more preferably 10 nm to 30 nm.

  When the crystal grain size of the Fe nanoparticles 11 is 5 nm to 50 nm, the exchange spring magnet according to the present embodiment can achieve a desired residual magnetic flux density (magnetization). Further, when the crystal grain size of the Fe nanoparticle 11 is less than 5 nm, it becomes difficult to maintain the crystallinity of the Fe nanoparticle 11, and when the crystal grain size of the Fe nanoparticle 11 exceeds 50 nm, The ratio of the relative Fe nanoparticles 11 in the core / shell particles 10 increases, and it becomes difficult to combine both the coercive force and the residual magnetic flux density. The crystal grain size of the Fe nanoparticles 11 is more preferably 10 nm to 30 nm.

The Sm—Co phase 13 formed on the surface of the Fe nanoparticles 11 is a hard magnetic phase made of SmCo ₅ and made of a rare earth element (samarium: Sm) and a transition metal element (cobalt: Co). In the exchange spring magnet according to the present embodiment, the Sm—Co phase 13 and the Fe nanoparticles 11 interact with each other (exchange interaction), whereby excellent magnetic properties can be realized.

  The Sm—Co phase 13 is preferably 30 to 50% by volume with respect to the volume of the core / shell particles 10 shown on the left side of FIG. When the volume ratio of the Sm—Co phase 13 is less than 30% by volume, there is a possibility that the Fe nanoparticles 11 come into contact with each other when the core / shell particles 10 are combined by a sintering process described later. This is not preferable. Further, when the volume ratio of the Sm—Co phase 13 exceeds 50% by volume, the ratio of the relative Sm—Co phase 13 in the core / shell particles 10 is increased, and both the coercive force and the residual magnetic flux density are reduced. It becomes difficult to combine.

A nonmagnetic film 15 is formed on the surface of the Sm—Co phase 13. The nonmagnetic film 15 may be formed of samarium oxide containing Sm ₂ O ₃ as a main component generated by oxidation of SmCo ₅ constituting the Sm—Co phase 13, and is formed of carbon. May be. In addition, the said substance is an example to the last, Comprising: The component of the nonmagnetic film 15 which concerns on this embodiment is not necessarily limited to the said substance.

  The film thickness of the nonmagnetic film 15 formed on the surface of the Sm—Co phase 13 is preferably 1 nm to 5 nm. When the film thickness of the nonmagnetic film 15 is less than 1 nm, the exchange interaction between the adjacent Sm—Co phases 13 is blocked when the core / shell particles 10 are combined by a sintering process described later. It is difficult to do so. Further, when the film thickness of the nonmagnetic film 15 exceeds 5 nm, the ratio of the nonmagnetic film 15 in the core / shell particles 10 becomes relatively large, and the magnetic characteristics of the core / shell particles 10 are deteriorated. .

  The crystal grain size of the core / shell particle 10 composed of such three layers is 10 nm to 100 nm. When the crystal particle size of the core / shell particle 10 is less than 10 nm and when the crystal particle size of the core / shell particle 10 is more than 100 nm, the exchange spring magnet in which the core / shell particle 10 is combined is used. The desired magnetic properties cannot be realized. Moreover, the crystal grain size of the core / shell particle 10 is more preferably 10 nm to 50 nm.

As shown on the left side of FIG. 1, the core / shell particle 10 according to the present embodiment has a core / shell structure in which the Fe nanoparticle 11 is the core and the Sm—Co phase 13 and the nonmagnetic film 15 are the shell. It is what you have. On the other hand, the core / shell particle 10 and the core / shell structure according to the present embodiment, the core / shell structure being reversed, the hard magnetic nanoparticle made of SmCo ₅ is used as the core, and the soft magnetic phase made of α-Fe is used as the shell / A shell structure is also conceivable. However, when the core / shell particles are combined using the α-Fe phase as the shell, the Fe phases may come into contact with each other as the Fe grains grow. It must be limited, and it becomes difficult to obtain a high residual magnetic flux density (magnetization). Conversely, by adopting a core / shell structure in which α-Fe is the core and SmCo ₅ is the shell, as in the core / shell particle 10 according to the present embodiment, the α-Fe is combined so as not to contact each other. Therefore, it is possible to further increase the upper limit value of the abundance of α-Fe and further improve the residual magnetic flux density.

  In the present embodiment, the core / shell particles 10 as described above are combined (composited) by heat treatment (sintering) as shown on the right side of FIG. 1 to obtain an exchange spring magnet. By combining the core / shell particle 10 according to the present embodiment, a part of the core / shell particle 10 is schematically shown on the right side of FIG. It becomes possible to realize a uniform composite nanostructure in which the -Co phase 13 is alternately dispersed, and the Fe core particles 11 are not in direct contact with each other. In addition, the presence of the nonmagnetic film 15 made of samarium oxide or carbon between adjacent Sm—Co phases 13 causes the Sm—Co phases 13 to be separated from each other by the nonmagnetic film 15. It is possible to prevent the exchange interaction from working. As a result, in the exchange spring magnet according to the present embodiment, the exchange interaction between the Fe nanoparticle 11 and the Sm—Co phase 13 allows the permanent magnet with excellent magnetic properties to have high coercive force and residual magnetic flux density. A magnet can be realized.

  Further, when the exchange spring magnet according to the present embodiment is applied to a permanent magnet type motor, the torque T is determined by the following expression (10).

T∝P _n · Ψ _a · i _q (Formula 10)

Here, in Equation 10 above, P _n represents the number of motor poles, Ψ _a represents the magnetic flux of the rotor magnet, and i _q represents the current of the stator winding. Since the exchange spring magnet according to the present embodiment has _a larger magnetic flux Ψa than _a neodymium magnet conventionally used for a motor or the like, the motor output can be significantly improved.

  Here, in the core / shell particle 10 according to the present embodiment, whether or not the Fe nanoparticle 11, the Sm—Co phase 13, and the nonmagnetic film 15 are formed depends on whether the manufactured core / shell particle 10 is a transmission electron. Confirmation is made by observing with a microscope (Transmission Electron Microscope: TEM) or by performing X-ray diffraction analysis to determine whether a diffraction peak derived from Fe and a diffraction peak derived from SmCo5 exist. be able to.

  The crystal grain size in the core / shell particle 10 according to the present embodiment is obtained by using a method based on the Hall equation shown in the following Equation 11 (Hole method) using the measurement result of X-ray diffraction. It can be specified by using it. This hole method is a method for evaluating the spread of an X-ray diffraction peak caused by both the size of a microcrystal (crystallite) that can be regarded as a single crystal (ie, crystal grain size) and non-uniform strain.

・・・（式１１）

... (Formula 11)

Here, in the above formula 11, B _r is a parameter indicating the spread (integral width) of the peak of the diffracted X-rays caused by the size of the crystallite epsilon, 2Ita is adjacent crystallites or the same crystallite It is a parameter representing the magnitude distortion (non-uniform distortion). Θ is the diffraction angle of the diffracted X-ray, and λ is the wavelength of the X-ray used.

Specifically, for a plurality of diffraction peaks, an integral width representing the width of a rectangle having the same peak height and the same area is calculated, and a graph having B _r cos θ and sin θ as coordinate axes is created. As apparent from the above equation 11, since there is a linear correlation between B _r cos θ and sin θ, the non-uniform distortion 2η can be specified based on the slope of the straight line appearing in the graph, and B _r Based on the intercept on the cos θ axis, the crystallite size ε can be specified.

  The volume ratio of the Sm—Co phase 13 and the thickness of the nonmagnetic film 15 are obtained by observing the core / shell particles 10 according to the present embodiment with a transmission electron microscope and performing image processing on a contrast image regarding the transmittance. Can be identified.

  In addition, the magnetic properties (for example, coercive force and residual magnetic flux density) of the exchange spring magnet according to the present embodiment can be measured by a known method, but for example, measured using a vibrating sample magnetometer. Can do.

  The crystal grain size, volume ratio, and nonmagnetic film measurement method that can be used in this embodiment are not limited to the above methods, and other known methods can be used. .

  The exchange spring magnet according to the present embodiment has been described in detail above with reference to FIG.

<About the manufacturing method of the exchange spring magnet>
Next, a method for manufacturing the exchange spring magnet according to the present embodiment will be described.
As described above, in the conventional solution synthesis method, it was difficult to form a uniform composite nanostructure having a desired composition and crystal grain size. However, the exchange spring magnet according to the present embodiment described below will be described. In this manufacturing method, an exchange spring magnet having a desired composition and crystal grain size and having a uniform composite nanostructure can be manufactured by a solution synthesis method.

  Hereinafter, the flow of the exchange spring magnet manufacturing method according to the present embodiment will be described in detail with reference to FIG. FIG. 2 is a flowchart showing an example of the flow of the method for manufacturing the exchange spring magnet according to the present embodiment.

  As illustrated in FIG. 2, the method for manufacturing the exchange spring magnet according to this embodiment is roughly divided into the following five steps.

(1) Generation of Co / Fe core / shell particles (step S101)
(2) Generation of Sm ₂ O ₃ / Co / Fe core / shell particles (step S103)
(3) Generation of SmCo ₅ / Fe core / shell particles (step S105)
(4) Formation of nonmagnetic film (step S107)
(5) Decomposition (step S109)

[Generation of Co / Fe core / shell particles]
In order to produce Co / Fe core / shell particles, based on a solution synthesis method, a metal complex containing α-Fe (hereinafter referred to as Fe complex) and a metal complex containing Co (hereinafter referred to as Co complex) And in a predetermined organic solvent.

  More specifically, the Fe complex and the Co complex are mixed in a predetermined organic solvent, heated to a predetermined temperature at a predetermined temperature increase rate, and the heated solution is held for a predetermined period of time at room temperature. Reduce the temperature until. Thereby, Co / Fe core / shell particles having a core / shell structure in which Fe becomes a core and Co becomes a shell can be generated.

Here, as the Fe complex, for example, Fe pentacarbonyl (chemical formula: Fe (CO) ₅ ) or the like can be used. Further, as the Co complex, for example, Co _{octacarbonyl:} it is possible to use the (Formula Co 2 _{(CO) 8)} and the like. In addition, the example of said Fe complex and Co complex is an example to the last, and the Fe complex and Co complex which can be utilized in this embodiment are not necessarily limited to said example.

Moreover, as an organic solvent utilized for the said reaction, it is possible to use, for example, oleylamine (C ₁₈ H ₃₇ N), oleic acid (C ₁₈ H ₃₄ O ₂ ), tetralin (C ₁₀ H ₁₂ ), and the like. . In addition, the example of said organic solvent is an example to the last, and the organic solvent which can be utilized in this embodiment is not necessarily limited to said example.

[Generation of Sm ₂ O ₃ / Co / Fe Core / Shell Particles]
Next, the produced Co / Fe core / shell particles and a metal complex containing Sm (hereinafter referred to as Sm complex) are mixed with a predetermined organic material so that the molar ratio of samarium to cobalt is 1: 5.2. Mix in solvent and react based on solution synthesis method. Then, the solution is heated to a predetermined temperature at a predetermined temperature increase rate, the heated solution is held for a predetermined time, and the temperature is lowered to room temperature. As a result, a phase composed of samarium oxide (Sm ₂ O ₃ ) is formed on the Co phase. As a result, Sm ₂ O ₃ / Co / Fe core / shell particles having a core / shell structure in which Fe becomes a core and Co or Sm ₂ O ₃ becomes a shell can be generated.

Here, as the Sm complex, for example, Sm triacetylacetonate (chemical formula: Sm (acac) ₃ ) or the like can be used. Moreover, as an organic solvent, it is possible to use the same thing as the above. In addition, the example of said Sm complex is an example to the last, and the Sm complex which can be utilized in this embodiment is not necessarily limited to said example.

[Generation of SmCo ₅ / Fe Core / Shell Particles]
Subsequently, the generated Sm ₂ O ₃ / Co / Fe core / shell particles are held at a predetermined temperature for a predetermined time to heat-treat the core / shell particles, and SmCo ₅ / Fe core / shell particles are Generate. Thereby, SmCo ₅ / Fe core / shell particles having a core / shell structure with Fe nanoparticles as the core and Sm—Co phase composed of SmCo ₅ as the shell can be generated.

The volume ratio of the Sm—Co phase made of SmCo ₅ can be controlled by adjusting the molar ratio of samarium and cobalt, the length of the holding time in steps S101 to S105, and the like. .

[Generation of non-magnetic film]
Next, the surface of the produced SmCo ₅ / Fe core / shell particles is coated with a nonmagnetic film such as an oxide film or carbon. The method for producing the nonmagnetic film can be performed by a known method. For example, when an oxide film is formed, oxygen is gradually introduced into the reaction atmosphere to form Sm _{2 on} the surface of SmCo _5. An oxide film mainly composed of O ₃ can be formed.

  The core / shell particles 10 as shown on the left side of FIG. 1 can be manufactured by the above processing.

[Composite]
Subsequently, the SmCo ₅ / Fe core / shell particles on which the non-magnetic film is formed are subjected to pressure sintering at a predetermined temperature, thereby compositing the core / shell particles 10 as shown on the left side of FIG. As a result, an exchange spring magnet having a uniform composite nanostructure as shown on the right side of FIG. 1 can be manufactured.

  The manufacturing method of the exchange spring magnet according to the present embodiment has been described in detail above with reference to FIG.

  Subsequently, the replacement spring magnet according to the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to the following Example.

<Manufacture of exchange spring magnets>
Oleylamine, which is an organic solvent, and Fe pentacarbonyl having a crystal grain size shown in Table 1 below were mixed, heated to a temperature of about 200 ° C., and then lowered to room temperature. Thereafter, Co octacarbonyl was mixed into the solution containing the Fe complex, heated to a temperature of about 300 ° C. at a rate of 2 ° C./min, and held for 2 hours or more. Thereafter, the temperature of the solution was lowered to room temperature to produce Co / Fe core / shell particles.

Subsequently, the produced Co / Fe core / shell particles and Sm triacetylacetonate are mixed in a solvent in which oleylamine and oleic acid are mixed so that the samarium: cobalt ratio is a molar ratio of 1: 5.2. And heated to 250 ° C. at a rate of 2 ° C./min and held for 4 hours or more. Thereafter, the temperature of the solution was lowered to room temperature to produce Sm ₂ O ₃ / Co / Fe core / shell particles.

Next, the produced Sm ₂ O ₃ / Co / Fe core / shell particles, Ca powder and KCl powder were mixed and held at 900 ° C. for 1 hour or longer, then the temperature was lowered to room temperature, and SmCo ₅ / Fe core / Shell particles were produced.

Then, the surface of the produced SmCo ₅ / Fe core / shell particles was coated with an oxide film to produce core / shell particles as shown on the left side of FIG.

  The obtained core / shell particles are subjected to X-ray diffraction analysis to specify the crystal particle diameter of the core / shell particles, and to determine the volume ratio of the Sm-Co phase and the thickness of the nonmagnetic film using a transmission electron microscope. It was measured by image processing. The obtained results are shown in Table 1 below.

Next, the obtained core / shell particles were subjected to pressure sintering at a temperature of 900 ° C. or lower to produce an SmCo ₅ / Fe exchange spring magnet as shown on the right side of FIG.

Here, in Examples 1 to 3 shown in Table 1 below, the particle size of the core / shell particles was changed while keeping the volume ratio of SmCo ₅ constant. In Examples 4 and 5 shown in Table 1 below, the volume ratio of SmCo ₅ was changed with the particle diameter of the core / shell particles being constant.

  The exchange spring magnet manufactured in this way was measured for coercive force and residual magnetic flux density using a vibrating sample magnetometer.

In addition, as a comparative example of the exchange spring magnet according to the present embodiment, a SmCo ₅ / Fe exchange spring magnet manufactured from one alloy composition by a liquid quenching method (Comparative Example 1) and SmCo ₅ using a solution synthesis method An SmCo ₅ / Fe exchange spring magnet produced by separately producing and mixing Fe (Comparative Example 2) was produced.

  The exchange spring magnet manufactured in this way was also measured for coercive force and residual magnetic flux density in the same manner.

Here, in Table 1 shown below,
1 [Oe] (Oersted) = (10 ³ / 4π) [A / m]
1 [emu] = 4π × 10 ⁻¹⁰ [Wb · m]
It is.

  As is clear from Table 1 above, the exchange spring magnet manufactured by the liquid rapid solidification method and the exchange spring magnet manufactured by the solution synthesis method cannot obtain high coercive force and high residual magnetic flux density. The exchange spring magnet manufactured by the manufacturing method according to the embodiment was able to obtain excellent coercive force and residual magnetic flux density.

  Thus, by using the method for manufacturing an exchange spring magnet according to the present embodiment, an exchange spring magnet having a high coercive force and a high residual magnetic flux density can be manufactured.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

10 Core / shell particles 11 Fe nanoparticles 13 Sm-Co phase 15 Nonmagnetic film

Claims (10)

Fe nanoparticles having a predetermined particle size;
Sm—Co phase provided around the Fe nanoparticles and made of SmCo ₅ ;
A non-magnetic film provided around the Sm-Co phase;
Consisting of core / shell particles having a particle size of 10 to 100 nm,
An exchange spring magnet having a structure in which the core / shell particles are combined. The exchange spring magnet according to claim 1, wherein the nonmagnetic film has a thickness of 1 to 5 nm. The exchange spring magnet according to claim 1, wherein the nonmagnetic film is made of samarium oxide or carbon containing Sm ₂ O ₃ as a main component. The said Sm-Co phase in the said core / shell particle is 30-50 volume% with respect to the volume of the said core / shell particle, The any one of Claims 1-3 characterized by the above-mentioned. Replacement spring magnet. The exchange spring magnet according to any one of claims 1 to 4, wherein the Fe nanoparticles have a particle size of 5 to 50 nm. Reacting an Fe complex containing Fe with a Co complex containing Co in a predetermined organic solvent to produce Co / Fe core / shell particles;
Reacting the produced Co / Fe core / shell particles with an Sm complex containing Sm in a predetermined organic solvent to produce Sm ₂ O ₃ / Co / Fe particles;
Heat-treating the produced Sm ₂ O ₃ / Co / Fe particles at a predetermined temperature to produce SmCo ₅ / Fe core / shell particles;
Forming a non-magnetic film on the surface of the generated SmCo ₅ / Fe core / shell particles;
Sintering the SmCo ₅ / Fe core / shell particles produced with the non-magnetic film to form a composite;
Including
The method of manufacturing an exchange spring magnet, wherein a particle diameter of the SmCo ₅ / Fe core / shell particles formed with the nonmagnetic film is 10 to 100 nm. The volume fraction of SmCo ₅ in the SmCo ₅ / Fe core / shell particles, the volume of the SmCo ₅ / Fe core / shell particles, characterized in that 30 to 50% of claim 6 A method of manufacturing a replacement spring magnet. 8. The method of manufacturing an exchange spring magnet according to claim 6, wherein the nonmagnetic film formed on the SmCo ₅ / Fe core / shell particles has a thickness of 1 to 5 nm. The non-magnetic layer is characterized by comprising a samarium oxide or carbon as a main component Sm ₂ O _3, the manufacturing method of the exchange-spring magnet according to any one of 6-8. 10. The method for producing an exchange spring magnet according to claim 6, wherein the particle size of Fe in the SmCo ₅ / Fe core / shell particles is 5 to 50 nm.

Images