KR102125168B1 - Hybrid magnetic fiber and fabricating method of the same - Google Patents

Abstract

A method of manufacturing a hybrid magnetic fiber is provided. The hybrid magnetic fiber manufacturing method comprises the steps of preparing a source solution comprising a first source material comprising a rare earth element, and a second source material comprising a transition metal element, by electrospinning the source solution to form a rare earth oxide and Forming a preliminary hybrid magnetic fiber comprising a transition metal oxide, and reducing the preliminary hybrid magnetic fiber to form a magnetic crystal comprising a compound of the rare earth element and the transition metal element, and the transition metal element And forming a hybrid magnetic fiber including a magnetic boundary layer.

Description

Hybrid magnetic fiber and fabricating method of the same}

The present invention relates to a hybrid magnetic fiber and a method for manufacturing the same, and relates to a hybrid magnetic fiber including both hard and soft magnetic materials and a method for manufacturing the same.

Permanent magnets, which are widely used in the electric, electronic and motor industries, are broadly classified into rare earth magnets and non-rare earth magnets such as ferrite and alnico. Rare earth magnets refer to compounds between rare earth metals and transition metals, and the maximum magnetic energy ((BH)max) value is superior to that of non-rare earth permanent magnets, so it is essential to keep pace with the recent weight reduction, miniaturization, and high performance of electronic products. It is an indispensable material. However, due to the increase in the price of rare earth metals and the imbalance in the distribution of rare earth resources, studies on rare earth reduction or non-rare earth magnet synthesis and alternative permanent magnet synthesis are currently being attempted.

For example, in the Republic of Korea Patent Publication No. 10-2017-0108468 (application number: 10-2016-0032417, applicant: Yonsei University Industry-University Cooperation Foundation), a substrate, and formed on the substrate, a Bi thin film layer and a Mn thin film layer laminated Disclosed is a non-rare permanent magnet with improved coercive force, comprising a thin film laminate obtained by repeatedly laminating and heat-treating units at least twice or more, and a method for manufacturing the same.

Republic of Korea Patent Publication No. 10-2017-0108468

One technical problem to be solved by the present invention is to provide a hybrid magnetic fiber with improved coercive force and saturation magnetization and a method for manufacturing the same.

Another technical problem to be solved by the present invention is to provide a hybrid magnetic fiber having an improved maximum magnetic energy value and a method for manufacturing the same.

Another technical problem to be solved by the present invention is to provide a hybrid magnetic fiber having a reduced amount of rare earth and a method for manufacturing the same.

The technical problem to be solved by the present invention is not limited to the above.

In order to solve the above technical problems, the present invention provides a hybrid magnetic fiber manufacturing method.

According to one embodiment, the hybrid magnetic fiber manufacturing method comprises the steps of preparing a source solution comprising a first source material comprising a rare earth element, and a second source material comprising a transition metal element, electrospinning the source solution By forming a pre-hybrid magnetic fiber comprising a rare earth oxide and a transition metal oxide, and reducing the pre-hybrid magnetic fiber, a magnetic crystal comprising a compound of the rare earth element and the transition metal element, And forming a hybrid magnetic fiber including a magnetic boundary layer including the transition metal element.

According to an embodiment, the magnetic crystal may have a hard-magnetic property, and the magnetic boundary layer may include a soft-magnetic property.

According to one embodiment, the magnetic boundary layer may include following the magnetization behavior of the magnetic crystal.

According to one embodiment, the mole fraction of the rare earth element in the source solution may include more than 9.290 at% and less than 10.562 at%.

According to one embodiment, the hybrid magnetic fiber forming step, mixing the preliminary hybrid magnetic fiber with a reducing agent, heat-treating the preliminary hybrid magnetic fiber mixed with the reducing agent, and heat-treated the preliminary hybrid magnetic fiber , Washing with a washing solution.

According to an embodiment, the preliminary hybrid magnetic fiber mixed with the reducing agent may include heat treatment at a temperature of more than 500°C and less than 800°C.

According to one embodiment, the reducing agent may include calcium (Ca).

According to one embodiment, the washing solution may include at least one of ammonium chloride (NH ₄ Cl), and methanol (CH ₃ OH).

According to one embodiment, the source solution may further include a crystallization source comprising a metal, and a viscous source comprising a polymer.

According to one embodiment, the rare earth element may include any one of La, Ce, Pr, Nd, Sm, or Gd.

According to an embodiment, the transition metal element may include any one of Fe, Co, or Ni.

In order to solve the above technical problems, the present invention provides a hybrid magnetic fiber.

According to an embodiment, the hybrid magnetic fiber is disposed between a plurality of magnetic crystals including a compound of a rare earth element and a transition metal element, and the magnetic crystals adjacent to each other to surround the magnetic crystal, It may include a magnetic boundary layer (magnetic boundary layer) containing the transition metal element.

According to an embodiment, in the hybrid magnetic fiber, the volume fraction of the magnetic boundary layer may include more than 0 vol% and less than 10 vol%.

According to an embodiment, the magnetic crystal has hard magnetic properties, the magnetic boundary layer has soft magnetic properties, and the magnetic boundary layer may include following the magnetization behavior of the magnetic crystal.

Method of manufacturing a hybrid magnetic fiber according to an embodiment of the present invention, preparing a source solution comprising a first source material containing a rare earth element, and a second source material containing a transition metal element, the source solution Electrospinning to form a preliminary hybrid magnetic fiber comprising a rare earth oxide and a transition metal oxide, and reducing the preliminary hybrid magnetic fiber to include a compound of the rare earth element and the transition metal element, and hard magnetic properties. And forming a hybrid magnetic fiber including a magnetic crystal having a magnetic crystal layer, and a magnetic boundary layer having soft magnetic properties.

In addition, in the method of manufacturing the hybrid magnetic fiber according to the embodiment, as the molar fraction of the rare earth element in the source solution is controlled, the volume fraction of the magnetic boundary layer in the hybrid magnetic fiber is controlled, resulting in the magnetic determination And a self-exchange coupling effect between the magnetic boundary layers. Accordingly, while maintaining high coercivity, saturation magnetization is increased, and further, the maximum magnetic energy ((BH)max) value is improved, thereby providing a hybrid magnetic fiber exhibiting excellent magnetic properties. Can be.

1 is a flowchart illustrating a method of manufacturing a hybrid magnetic fiber according to an embodiment of the present invention.
Figure 2 is a flow chart specifically explaining the hybrid magnetic fiber forming step of the method of manufacturing a hybrid magnetic fiber according to an embodiment of the present invention.
3 is a view showing a manufacturing process of a hybrid magnetic fiber according to an embodiment of the present invention.
4 is a view showing a hybrid magnetic fiber according to an embodiment of the present invention.
5 is a graph showing the properties of soft and hard magnetic materials.
Figure 6 is a graph showing the characteristics of the case where the self-exchange coupling effect between soft and hard magnetic materials is shown.
7 and 8 are photographs of hybrid magnetic fibers according to Example 1 of the present invention.
9 to 11 is a photograph comparing the characteristics according to the temperature of the heat treatment in the process of manufacturing a hybrid magnetic fiber according to Example 1 of the present invention.
12 is a photograph comparing the effect of the washing solution in the process of washing the hybrid magnetic fiber according to Example 1 of the present invention.
13 is a photograph of a hybrid magnetic fiber according to Example 2 of the present invention.
14 is a graph showing the Sm-Co two-component system.
15 is a graph showing the effect of the molar fraction of rare earth elements contained in the source solution on the structure of the hybrid magnetic fiber according to Example 2 of the present invention.
16 and 17 are graphs showing the effect of the molar fraction of rare earth elements included in the source solution on the structure of the hybrid magnetic fiber according to Example 1 of the present invention.
18 is a graph showing the properties of a hybrid magnetic fiber according to a comparative example of the present invention in which no self-exchange coupling effect occurs.
19 is a graph showing the effect of the volume fraction of the magnetic boundary layer on the magnetic properties of the hybrid magnetic fiber according to Example 1 of the present invention.
20 is a graph showing the effect of the volume fraction of magnetic crystals on the residual magnetization value of the hybrid magnetic fiber according to Example 1 of the present invention.
21 is a graph showing the effect of the volume fraction of magnetic crystals on the maximum magnetic energy value of the hybrid magnetic fiber according to Example 1 of the present invention.
22 and 23 are graphs showing reformation of the Recoil curve of hybrid magnetic fibers according to Example 1 of the present invention, in which the volume fractions of the magnetic crystals and the magnetic crystal layers are different.
24 is a graph showing Recoil susceptibility values of hybrid magnetic fibers according to Example 1 of the present invention having different volume fractions of the magnetic boundary layer.
25 to 27 are graphs comparing characteristics according to temperature to be heat-treated in the process of manufacturing a hybrid magnetic fiber according to Example 1 of the present invention.
28 is a graph showing changes in properties according to the heat treatment temperature of the rare earth oxide.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical spirit of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed contents are thorough and complete and that the spirit of the present invention is sufficiently conveyed to those skilled in the art.

In the present specification, when a component is referred to as being on another component, it means that it may be formed directly on another component, or a third component may be interposed between them. In addition, in the drawings, the thickness of the films and regions are exaggerated for effective description of the technical content.

In addition, in various embodiments of the present specification, terms such as first, second, and third are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another component. Therefore, what is referred to as the first component in one embodiment may be referred to as the second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. In addition, in this specification,'and/or' is used to mean including at least one of the components listed before and after.

In the specification, a singular expression includes a plural expression unless the context clearly indicates otherwise. Also, terms such as “include” or “have” are intended to indicate the presence of features, numbers, steps, elements, or combinations thereof described in the specification, and one or more other features, numbers, steps, or configurations. It should not be understood as excluding the possibility or presence of elements or combinations thereof. In addition, in this specification, "connecting" is used in a sense to include both indirectly connecting a plurality of components, and directly connecting.

In addition, in the following description of the present invention, when it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

1 is a flowchart illustrating a method of manufacturing a hybrid magnetic fiber according to an embodiment of the present invention, and FIG. 2 is a flowchart illustrating a step of specifically forming a hybrid magnetic fiber among the methods of manufacturing a hybrid magnetic fiber according to an embodiment of the present invention 3 is a view showing a manufacturing process of a hybrid magnetic fiber according to an embodiment of the present invention, and FIG. 4 is a view showing a hybrid magnetic fiber according to an embodiment of the present invention.

1 to 4, a source solution including a first source material and a second source material may be prepared (S100 ). According to one embodiment, the first source material may include a rare-earth element. For example, the rare earth element may include any one of La, Ce, Pr, Nd, Sm, or Gd. According to one embodiment, the second source material may include a transition-metal element. For example, the transition metal element may include any one of Fe, Co, or Ni.

The source solution may further include a crystallization source and a viscous source. According to one embodiment, the crystallization source may include a metal. For example, the metal may be a metal water-soluble salt such as copper (Cu) or zirconium (Zr). The crystallization source can improve the crystallinity of the hybrid magnetic fiber 100 to be described later. According to one embodiment, the viscous source may include a polymer. For example, the polymer may include at least one of polyvinylpyrrolidone (PVP), polyacrylonitrile (PAN), poly(vinyl acetate) (PVAC), polyvinylbutyral (PVB), poly(vinyl alcohol) (PVA), or polyethylene oxide (PEO). It can contain. The viscous source may provide viscosity to the source solution to control the diameter of the hybrid magnetic fiber 100 described below.

According to one embodiment, the mole fraction (at %) of the rare earth element in the source solution may be controlled. Specifically, the mole fraction of the rare earth element in the source solution may be controlled to be greater than 9.290 at% and less than 10.562 at%. In this case, an exchange-coupling effect may be generated between the magnetic crystal 110 and the magnetic boundary layer 120 included in the hybrid magnetic fiber 100 described below. In addition, the mole fraction of the rare earth element in the source solution may be controlled to be greater than 10.156 at% and less than 10.562 at%. In this case, the self-exchange coupling effect generated between the magnetic crystal 110 and the magnetic boundary layer 120 included in the hybrid magnetic fiber 100 described below may have a maximum value. More detailed description will be given later.

The source solution may be electrospinned to form a preliminary hybrid magnetic fiber (S200). The preliminary hybrid magnetic fiber formed by electrospinning the source solution may include a rare earth oxide and a transition metal oxide.

According to one embodiment, the preliminary hybrid magnetic fiber forming step may include a first preliminary hybrid magnetic fiber forming step, and a second preliminary hybrid magnetic fiber forming step. The first preliminary hybrid magnetic fiber forming step may be performed by a method of electrospinning the source solution. The first preliminary hybrid magnetic fiber may be formed of a solid component of the source solution. The first preliminary hybrid magnetic fiber may include a water-soluble metal salt, a polymer, and the like. The step of forming the second preliminary hybrid magnetic fiber may be performed by a method of calcining the first preliminary hybrid magnetic fiber. That is, the first preliminary hybrid magnetic fiber may be heat-treated to decompose an organic material including a polymer in the first preliminary hybrid magnetic fiber. The second preliminary hybrid magnetic fiber may include rare earth oxide, transition metal oxide, and rare earth-transition metal oxide.

More specifically, the source solution may be injected into a syringe (10), and the source solution may be radiated using a syringe pump (20). In this case, the tip 30 of the syringe has an inner diameter of 0.05 to 2 mm, and the collector to which the syringe tip 30 and the preliminary hybrid magnetic fiber are collected are spaced 10 to 20 cm apart, and the syringe pump 20 ) Can spin the source solution at a rate of 0.3 to 0.8 mL/h. In addition, the voltage applied for electric radiation may be 16 to 23 kV. The first preliminary hybrid magnetic fiber may be formed through the above-described process.

The first preliminary hybrid magnetic fiber may be collected in an alumina crucible and heat-treated in an atmospheric pressure of 500 to 900°C in an atmospheric atmosphere. In this process, all organic substances including polymers can be thermally decomposed. At this time, the temperature increase rate condition may be 1 to 10°C per minute. The second preliminary hybrid magnetic fiber may be formed through the above-described process.

The preliminary hybrid magnetic fiber may be reduced to form a hybrid magnetic fiber 100 including a magnetic crystal (110), and a magnetic boundary layer (S300). According to one embodiment, the hybrid magnetic fiber 100 includes a plurality of the magnetic crystals 110, wherein the magnetic boundary layer 120 is disposed between the magnetic crystals 110 adjacent to each other, the magnetic crystals It may have a structure surrounding the (110).

The magnetic crystal 110 may include a compound of the rare earth element and the electrometal element. For example, the magnetic crystal 110 may include Nd ₂ Fe ₁₄ B, Sm ₂ Co ₁₇ , and the like. Accordingly, the magnetic crystal 110 may have a hard-magnetic characteristic. Alternatively, the magnetic boundary layer 120 may include the transition metal element. For example, the magnetic boundary layer 120 may include fcc-Fe, fcc-Co, and the like. Accordingly, the magnetic boundary layer 120 may have soft-magnetic properties.

Unlike the above, according to another embodiment, the hybrid magnetic fiber 100 is a chain in which the first single crystal 110 of hard magnetic properties and the second single crystal 120 of soft magnetic properties are alternately and repeatedly arranged. It can have a structure.

That is, the hybrid magnetic fiber 100 according to the embodiment may have any one structure of a magnetic crystal 110-a magnetic boundary layer 120 structure, or a first single crystal 110-a second single crystal 120 chain structure. Can be. The structure of the hybrid magnetic fiber 100 includes the conditions of the electrospinning process described above, the heat treatment condition in the heat treatment reduction step described later, and the hard magnetic property material and the soft magnetic property material in the hybrid magnetic fiber 100. It can be determined according to the volume ratio. Specifically, when controlled under the conditions of the electrospinning process, when the diameter of the hybrid magnetic fiber 100 is less than 500nm, the hybrid magnetic fiber 100 is the first single crystal 110-second single crystal 120 ) It can be formed into a chain structure. In addition, when the volume of the soft magnetic property material in the hybrid magnetic fiber 100 is 10 vol% or more, the hybrid magnetic fiber 100 may be formed of a first single crystal 110-second single crystal 120 chain structure. Can be.

The hybrid magnetic fiber 100 may have different industrial fields depending on the shape of the structure to be formed. For example, when the hybrid magnetic fiber 100 has a magnetic crystal 110-magnetic boundary layer 120 structure, the hybrid magnetic fiber 100 may be sintered to be used in a high-power product in the form of a sintered magnet. In particular, it can be used in various advanced equipment such as hybrid motors (HEVs) and electric vehicles (EVs) for driving motors, small motors for vehicles, VCMs for hard disks, speakers for mobile phones, small parts in industrial robots, and MRI.

Alternatively, when the hybrid magnetic fiber 100 has a chain structure of a first single crystal 110 and a second single crystal 120, the hybrid magnetic fiber 100 is mixed with a binder material and molded to form a bond magnet ( Plastic magnets, rubber magnets). This has a low magnetic property compared to a sintered magnet, but can be used for door packing of a refrigerator, paper board of a bulletin board, various stationery, etc. due to its high processability, earthquake resistance, and impact resistance.

According to one embodiment, the hybrid magnetic fiber 100 forming step (S300) comprises mixing the preliminary hybrid magnetic fiber with a reducing agent (S310), and heat-treating the preliminary hybrid magnetic fiber mixed with the reducing agent ( S320), and washing the preheated hybrid magnetic fibers with a washing solution (S330). That is, as the preliminary hybrid magnetic fiber 100 is mixed with a reducing agent and then heat-treated, the hybrid magnetic fiber 100 may be formed.

The reducing agent may include calcium (Ca). For example, the reducing agent may include CaH ₂ . In this case, the hybrid magnetic fiber 100 can be easily formed. Specifically, in the case of rare earth elements, it has very small oxidation energy, so it can maintain the most stable phase in the form of oxide. Accordingly, in order to reduce the rare earth oxide to metal, a high temperature and a hydrogen atmosphere of 1500° C. or higher are required, and process difficulties arise. However, since calcium (Ca) has a smaller oxidation energy than rare earth elements, when it is used as a reducing agent, a relatively low heat treatment temperature (for example, 500 to 800°C) and a rare earth oxide metal in a non-hydrogen atmosphere Can be easily reduced.

The heat treatment temperature of the preliminary hybrid magnetic fiber mixed with the reducing agent may be controlled. Specifically, the preliminary hybrid magnetic fiber mixed with the reducing agent may be heat-treated at a temperature of more than 500°C and less than 800°C. In this case, the hybrid magnetic fiber 100 can be easily formed. Alternatively, when the preliminary hybrid magnetic fiber mixed with the reducing agent is heat-treated at a temperature of 500° C. or less, a problem that reduction is not performed may occur because the temperature is too low. In addition, when the preliminary hybrid magnetic fiber mixed with the reducing agent is heat-treated at a temperature of 800° C. or higher, the hybrid magnetic fiber 100 may not have a fiber shape and may be transformed into a particle shape.

The washing solution may include at least one of ammonium chloride (NH ₄ Cl), and methanol (CH ₃ OH). In this case, the hybrid magnetic fiber 100 can be easily formed. Specifically, when the preliminary hybrid magnetic fiber is reduced using a reducing agent containing calcium (Ca), calcium oxide (CaO) may be formed on the surface of the metal on which the rare earth oxide is reduced. Accordingly, a process for removing calcium oxide (CaO) is required. In the existing calcium oxide (CaO) removal process, a washing solution in which acetic acid or hydrochloric acid is mixed with ultrapure water was used. In this case, a problem may occur when the acid solution generates a fatal effect such as corrosion and oxidation even in the magnetic phase. However, in the case of a washing solution containing at least one of ammonium chloride (NH ₄ Cl) and methanol (CH ₃ OH), calcium oxide (CaO) can be easily removed without affecting the magnetic phase. .

According to one embodiment, in the hybrid magnetic fiber 100, the volume fraction (vol%) of the magnetic boundary layer 120 may be controlled. Specifically, in the hybrid magnetic fiber 100, the volume fraction of the magnetic boundary layer 120 may be controlled to be greater than 0 vol% and less than 10 vol%. In this case, the magnetic boundary layer 120 may follow the magnetization behavior of the magnetic crystal 110. That is, an exchange-coupling effect may be generated between the magnetic crystal 110 and the magnetic boundary layer 120. In addition, within the hybrid magnetic fiber 100, the volume fraction of the magnetic boundary layer 120 may be controlled to be greater than 0 vol% and less than 3 vol%. In this case, the self-exchange coupling effect generated between the magnetic crystal 110 and the magnetic boundary layer 120 may have a maximum value.

5 is a graph showing the properties of the soft magnetic and hard magnetic materials, Figure 6 is a graph showing the properties of the magnetic exchange coupling effect between the soft magnetic and hard magnetic materials.

5 and 6, in the case of a soft magnetic material, as shown in FIG. 5(a), saturation magnetization (M _s ) is relatively high, and coercivity (H _C ) is relatively It may have a characteristic that appears low. On the other hand, in the case of the hard magnetic material, as shown in FIG. 5(b), the coercive force (H _C ) is relatively high and the saturation magnetization (M _s ) can be relatively low. However, when a self-exchange coupling effect is generated between the soft magnetic material and the hard magnetic material, as shown in FIG. 6, coercive force (H _c ) and saturation magnetization (M _S ) are both high. As a result, the material exhibiting the self-exchange bonding effect between the hard magnetic material and the soft magnetic material has excellent magnetic properties and can be easily used as a permanent magnet.

As described above, the hybrid magnetic fiber 100 according to the embodiment includes the magnetic crystal 110 of hard magnetic properties included in the hybrid magnetic fiber 100, and the magnetic boundary layer 120 of soft magnetic properties. A self-exchange coupling effect may occur between them. To this end, the volume fraction of the magnetic boundary layer 120 in the hybrid magnetic fiber 100 may be controlled. In addition, the volume fraction of the magnetic boundary layer 120 in the hybrid magnetic fiber 100 may be controlled by the molar fraction of the rare earth element in the source solution. The mole fraction of the rare earth element in the source solution according to the volume fraction of the magnetic boundary layer 120 in the hybrid magnetic fiber 100 may be calculated through Equation 1 below.

<Equation 1>

: 소스 용액 내의 희토류 원소 몰 분율,

: 자성 결정의 밀도,

: 하이브리드 자성 섬유 내의 자성 결정의 부피 분율(0.0~1.0),

: 자성 결정 내 희토류 원소의 원자 개수 (예: Sm₂Co₁₇에서

=2),

: 자성 결정의 분자량.

: 자성 경계층의 밀도,

: 자성 결정 내 전이금속 원소의 원자 개수 (예: Sm₂Co₁₇에서

=17),

: 자성 경계층의 분자량.)(

: Molar fraction of rare earth elements in the source solution,

: Density of magnetic crystals,

: Volume fraction of magnetic crystals in hybrid magnetic fibers (0.0-1.0),

: Atomic number of rare earth elements in magnetic crystals (e.g. in Sm ₂ Co ₁₇

=2),

: Molecular weight of magnetic crystal.

: Density of magnetic boundary layer,

: The number of atoms of the transition metal element in the magnetic crystal (eg, in Sm ₂ Co ₁₇

=17),

: Molecular weight of magnetic boundary layer.)

That is, by controlling the mole fraction of the rare earth element in the source solution, the volume fraction of the magnetic boundary layer 120 in the hybrid magnetic fiber 100 is controlled, and as a result, the magnetic crystal 110 and the magnetic boundary layer A magnetic exchange coupling effect may be generated between the 120. Specifically, when the molar fraction of the rare earth element in the source solution is controlled to be greater than 9.290 at% and less than 10.562 at%, the volume fraction of the magnetic boundary layer 120 in the hybrid magnetic fiber 100 is greater than 0 vol% 10 It can be controlled to less than vol%. In this case, a magnetic exchange coupling effect may be generated between the magnetic crystal 110 and the magnetic boundary layer 120. As a result, the hybrid magnetic fiber 100 according to the embodiment exhibits high magnetic properties and can be easily used as a permanent magnet. In other words, as the hybrid magnetic fiber 100 according to the embodiment may exhibit high magnetic properties through the mixing of a hard magnetic material and a soft magnetic material, the use of a rare earth material for manufacturing a permanent magnet may be reduced. Can be.

Unlike the method of manufacturing the hybrid magnetic fiber according to the above-described embodiment, conventionally, in order to mix the hard magnetic material and the soft magnetic material, a simple mixing method, a coating method, a vapor deposition method, a bulk (bulk) process, and a plasma process, etc. Was used.

In the case of the simple mixing method, as a method of physically bonding the hard magnetic nano-powder and the soft magnetic nano-powder, in order to generate a self-exchange bonding effect, there is a disadvantage that a process such as sintering must be additionally performed.

In the case of the coating method, a sol-gel coating method is typically used as a technique for forming a material having a core-shell structure by coating a soft magnetic material on a hard magnetic material. In the case of a sol-gel coating method, nano-powders such as chemical reaction of a hard magnetic substance in the heat treatment in the atmosphere for hydrogen formation and reduction and hydrogen heat treatment, and oxidation of a magnetic substance in the heat treatment process for removing organic substances Since it is very vulnerable to surface oxidation, ferrite in the form of oxide is mainly used. Accordingly, there is a problem in that it is difficult to expect higher magnetic properties than commercial hard magnetic materials.

In the case of the evaporation method, a technique for preparing a composite powder by coating a soft magnetic material on the surface of the hard magnetic material by electroless or electrolytic deposition, the process of immersing the hard magnetic material in an acidic solution containing hydrochloric acid (HCl), ammonia solution Oxidation and surface defects of the hard magnetic material may be generated from the process of using the containing basic plating solution. Accordingly, it is limited to use only in a stable oxide form of ferrite, and when the soft magnetic coating layer produced as a result of deposition is an oxide, there is a problem that an additional reduction heat treatment process is required.

In the case of the bulk process, there are technologies for producing hard and soft magnetic alloys from high-purity metal ingots, or techniques for depositing a hybrid structure of hard and soft materials through subsequent heat treatment of the amorphous hard magnetic materials, which is high Magnetic properties can be expected, but due to low coercive force, there is a problem that the range of use for the bonded magnet is limited.

In the case of the plasma process, it is possible to produce nano-sized hard magnetic and soft magnetic composite powders in an inert atmosphere, but requires an advanced heat source of 5,000 to 10,000 K for vaporization and dissolution of the powder, and it is difficult to control the size and volume. , In the powder collection process, a problem of reactivity between the nano powder and the gas may occur.

However, a method of manufacturing a hybrid magnetic fiber according to an embodiment of the present invention comprises the steps of preparing the source solution comprising a first source material containing a rare earth element and a second source material comprising a transition metal element, the Electrospinning a source solution to form the preliminary hybrid magnetic fiber comprising a rare earth oxide and a transition metal oxide, and reducing the preliminary hybrid magnetic fiber to include a compound of the rare earth element and the transition metal element, Forming the hybrid magnetic fiber 100 including the magnetic crystal (110) having hard magnetic properties, and the magnetic boundary layer (120) including the transition metal element and having soft magnetic properties It may include the steps.

In addition, in the method of manufacturing the hybrid magnetic fiber according to the embodiment, the volume fraction of the magnetic boundary layer 120 in the hybrid magnetic fiber 100 is controlled by controlling the mole fraction of the rare earth element in the source solution, As a result, a magnetic exchange coupling effect may be generated between the magnetic crystal 110 and the magnetic boundary layer 120. Accordingly, while maintaining high coercivity, saturation magnetization is increased, and further, the maximum magnetic energy ((BH)max) value is improved, thereby providing a hybrid magnetic fiber exhibiting excellent magnetic properties. Can be.

As described above, a hybrid magnetic fiber according to an embodiment of the present invention and a manufacturing method thereof have been described. Hereinafter, specific experimental examples and characteristics evaluation results of the hybrid magnetic fiber and the manufacturing method according to the embodiment of the present invention will be described.

According to Example 1 hybrid Magnetic fiber manufacturing

Samarium(III) nitrate hexahydrate; Sm(NO ₃ ) ₃ 6H ₂ O) and cobalt(II) nitrate hexahydrate; Co(NO ₃ ) in 4 mL of ultrapure water ) ₂ 6H ₂ O) was mixed with a solution in which 0.4 g of a PVP having a molecular weight of 1,300,000 was dissolved in 6 mL of ethanol to prepare a source solution.

The prepared source solution is placed in a syringe for electrospinning, and the syringe pump is used to continuously push the solution at a rate of 0.3 to 0.8 mL/h. At this time, the tip portion of the syringe and the collector where the spun fibers are collected are spaced apart at 15 cm intervals, and a high voltage (16-23 kV) is applied to radiate the source solution by a potential difference. The material deposited on the collector is collected in an alumina (Al ₂ O ₃ ) crucible and heat-treated for 3 hours at a temperature of about 700° C. in an atmosphere to decompose all organic substances including polymers. In the process the rare earth-containing oxide of SmCoO ₃ -Co ₃ O ₄ - a spare magnetic hybrid fibers comprising a transition metal oxide can be obtained.

The pre-hybrid magnetic fiber is mixed with CaH ₂ in a volume ratio of 1:1, and reduced by heat treatment for 3 hours at a temperature of about 700° C. in an inert atmosphere, followed by washing with ammonium chloride and methanol to obtain Sm of hard magnetic properties. _A hybrid magnetic fiber according to the first embodiment was prepared including a fcc-Co magnetic boundary layer having ₂ Co ₁₇ magnetic crystals and soft magnetic properties.

In addition, in order to control the volume fraction of the Sm ₂ Co ₁₇ magnetic crystals in the hybrid magnetic fiber according to the first embodiment, the mole fraction of the samarium element in the source solution was controlled, which was calculated through <Equation 2> below, The calculated results are summarized through <Table 1>.

<Equation 2>

(Sm(at%): Molar fraction of rare earth elements in the source solution, ρ _Sm2Co17 : density of Sm ₂ Co ₁₇ magnetic crystals, x _Sm2Co17 : volume fraction of Sm ₂ Co ₁₇ magnetic crystals in hybrid magnetic fiber (0.0-1.0), m _Sm : atomic number of rare earth elements in magnetic crystals, MW _Sm2Co17 : molecular weight of magnetic crystals ρ _Co : density of magnetic boundary layer, m _Co : atomic number of transition metal elements in magnetic crystals, MW _Co : molecular weight of magnetic boundary layer)

Volume fraction of magnetic crystal in hybrid magnetic fiber (Sm ₂ Co ₁₇ vol%) Molar fraction of rare earth elements in the source solution
(Sm at %) 100 10.562 99 10.409 97 10.156 95 9.906 90 9.290 80 8.101 50 4.803 30 2.786 10 0.885 0 0

According to Example 2 hybrid Magnetic fiber manufacturing

Neodymium(III) nitrate hexahydrate; Nd(NO ₃ ) ₃ 6H ₂ O) and iron(III) nitrate hexahydrate (Iron(III) nitrate nonahydrate; Fe(NO ₃ ) in 4.5mL ultrapure water ) ₃ 9H2O) was mixed with a solution of 0.6 g of PVP having a molecular weight of 1,300,000 in 3 mL of ethanol, and a source solution was prepared. Further, boric acid (H ₃ BO ₃ ) was further mixed as much as half of the number of moles of neodymium (III) nitrate hexahydrate.

The prepared source solution is placed in a syringe for electrospinning, and the syringe pump is used to continuously push the solution at a rate of 0.3 to 0.8 mL/h. At this time, the tip portion of the syringe and the collector in which the spun fibers are collected are separated at intervals of 18 cm, and a high voltage (16-23 kV) is applied to radiate the source solution by a potential difference. The material deposited on the collector is collected in an alumina (Al ₂ O ₃ ) crucible and heat-treated for 3 hours at a temperature of about 700° C. in an atmosphere to decompose all organic substances including polymers. In this process, a preliminary hybrid magnetic fiber comprising a rare earth oxide-transition metal oxide of NdFeO ₃ -NdBO ₃ -Fe ₂ O ₃ is obtained.

The pre-hybrid magnetic fiber is mixed with CaH ₂ in a volume ratio of 1:1, and reduced by heat treatment for 3 hours at a temperature of about 700° C. in an inert atmosphere, washed with ammonium chloride and methanol, and Nd of hard magnetic properties _{2 A} hybrid magnetic fiber according to a second embodiment was prepared comprising a Fe ₁₄ B magnetic crystal and an fcc-Fe magnetic boundary layer having soft magnetic properties.

In addition, in order to control the volume fraction of Nd ₂ Fe ₁₄ B magnetic crystals in the hybrid magnetic fiber according to the second embodiment, the molar fraction of the neodymium element in the source solution was controlled, which was calculated through Equation 3 below. , The calculated results are summarized through <Table 2>.

<Equation 3>

(Nd(at%): Molar fraction of rare earth elements in the source solution, ρ _Nd2Fe14B : density of Nd ₂ Fe ₁₄ B magnetic crystals, x _Nd2Fe14B : volume fraction of Nd ₂ Fe ₁₄ B magnetic crystals in hybrid magnetic fiber (0.0-1.0) , m _Nd : atomic number of rare earth elements in magnetic crystals, MW _Nd2Fe14B : molecular weight of magnetic crystals ρ _Fe : density of magnetic boundary layer, m _Fe : atomic number of transition metal elements in magnetic crystals, MW _Fe : molecular weight of magnetic boundary layer)

Volume fraction of magnetic crystals in hybrid magnetic fibers (Nd ₂ Fe ₁₄ B vol%) Molar fraction of rare earth elements in the source solution
(Nd at %) 100 12.505 99 12.348 97 12.037 95 11.729 90 10.973 80 9.515 50 5.541 30 3.180 10 1.016 0 0

In addition, the configuration of the hybrid magnetic fibers according to Examples 1 and 2 is summarized through <Table 3> below.

division Magnetic crystal Magnetic boundary layer Example 1 Sm ₂ Co ₁₇ Co Example 2 Nd ₂ Fe ₁₄ B Fe

Exemplary hybrid magnetic fiber prepared in Example 1 was prepared in the hybrid magnetic fibers in accordance with, and made to have a diameter of less than 250 nm, the hard magnetic properties single crystal according to Example 3, said embodiment having a chain structure of the soft magnetic characteristic single crystal Example 3 Hybrid magnetic fibers according to the were prepared.

The structures of the hybrid magnetic fibers according to Examples 1 to 3 are summarized through Table 4 below.

division rescue Example 1 Magnetic crystal-magnetic boundary layer structure Example 2 Magnetic crystal-magnetic boundary layer structure Example 3 Single crystal-single crystal chain structure

7 and 8 are photographs of hybrid magnetic fibers according to Example 1 of the present invention.

7 and 8, the mole fraction of the rare earth element in the source solution is controlled to 10.56 at%, 0 at%, 9.91 at%, and 4.80 at%. scanning electron microscope) were taken and shown in Figs. 7(a), 7(b), 8(a), and 8(b), respectively. As can be seen in Figures 7 and 8, it was confirmed that the hybrid magnetic fibers according to Example 1 were formed in the form of fibers having a diameter of about 500 nm.

9 to 11 is a photograph comparing the characteristics according to the temperature to be heat-treated in the process of manufacturing a hybrid magnetic fiber according to Example 1 of the present invention.

9 to 11, the hybridization according to the first embodiment formed by controlling the temperature to be heat treated in the reduction step of the preliminary hybrid magnetic fiber is 400 ℃, 500 ℃, 600 ℃, 700 ℃, 750 ℃, and 800 ℃ The SEMs of the magnetic fibers were taken in FIGS. 9(a), 9(b), 10(a), 10(b), 11(a), and 11(b), respectively. Shown.

As can be seen from (a) and (b) of FIG. 9, it was confirmed that when the temperature to be heat-treated in the reduction step is 400° C. and 500° C., reduction of rare earth oxides is not easily performed. In addition, as can be seen from (a) and (b) of FIG. 11, when the temperatures to be heat-treated in the reduction step are 750°C and 800°C, it was confirmed that the fibers did not maintain the shape and were deformed into particle shapes. On the other hand, as can be seen from (a) and (b) of FIG. 10, when the temperature to be heat-treated in the reduction step is 600°C and 700°C, it is confirmed that the reduction of the rare earth oxide is easily performed, and thus the hybrid magnetic fiber is easily formed Could.

12 is a photograph comparing the effect of the washing solution in the process of washing the hybrid magnetic fiber according to Example 1 of the present invention.

Referring to (a) and (b) of FIG. 12, in the process of washing the hybrid magnetic fiber according to Example 1, ammonium chloride and methanol were washed with the washing solution according to the mixed example of FIG. 12. (a), and the case where the ultrapure water and the weak acid were washed with a conventional washing solution is shown in FIG. 12(b). As can be seen from (a) and (b) of FIG. 12, when washed with a conventional washing solution, by-products remain on the fiber surface to degrade magnetic properties, whereas when washed with a washing solution according to the embodiment, magnetic It was confirmed that by-products other than fibers were selectively removed to obtain magnetic properties reaching theoretical values.

13 is a photograph of a hybrid magnetic fiber according to Example 2 of the present invention.

13 (a) to (c), the mole fraction of the rare earth element in the source solution is controlled to 12.5 at%, 3.18 at%, and 0 at%. Images were taken and are shown in Figs. 13A to 13C. 13(a) to 13(c), it was confirmed that hybrid magnetic fibers were easily formed even when Nd was used as the rare earth element and Fe was used as the transition metal element.

14 is a graph showing the Sm-Co two-component system.

Referring to FIG. 14, the state of the Sm-Co compound according to the molar fraction (at %) and temperature (°C) of Sm in the Sm-Co compound is shown. As can be seen in Figure 14, when the molar fraction of Sm in the Sm-Co compound is less than 10.6 at%, it was confirmed that the hard magnetic properties and soft magnetic properties coexist.

15 is a graph showing the effect of the molar fraction of rare earth elements included in the source solution on the structure of the hybrid magnetic fiber according to Example 2 of the present invention.

Referring to (a) to (c) of FIG. 15, the hybrid magnetism according to Example 2 formed by controlling the molar fraction of rare earth element (Nd) in the source solution to 12.5 at%, 3.18 at%, and 0 at%. Relative intensity (au) according to 2θ (degree) was measured for each fiber to show X-ray diffraction analysis. 15(a), when the molar fraction of the rare earth element in the source solution was 12.5 at%, it was confirmed that only the hard magnetic properties of Nd ₂ Fe ₁₄ B appear. In addition, as can be seen in Figure 15 (c), when the molar fraction of rare earth elements in the source solution is 0 at%, it was confirmed that only the soft magnetic properties of fcc-Fe appear. However, as can be seen from FIG. 15(b), when the molar fraction of the rare earth element in the source solution is 3.15 at%, it can be seen that both the hard magnetic properties of Nd ₂ Fe ₁₄ B and the soft magnetic properties of fcc-Fe appear. Could.

16 and 17 are graphs showing the effect of the molar fraction of rare earth elements included in the source solution on the structure of the hybrid magnetic fiber according to Example 1 of the present invention.

16 and 17, the hybrid magnetic fiber according to Example 2 formed by controlling the molar fraction of rare earth elements (Sm) in the source solution to 10.56 at%, 0 at%, 9.91 at%, and 4.80 at% X-ray diffraction analysis was performed by measuring the relative intensity (au) according to 2θ (degree) for each, and this was analyzed in FIGS. 16(a), 16(b), 17(a), and 17, respectively. It is shown in (b).

As can be seen in Figure 16 (a), when the molar fraction of the rare earth element in the source solution is 10.56 at%, it was confirmed that only the hard magnetic properties of Sm ₂ Co ₁₇ . In addition, as can be seen in FIG. 16(b), when the molar fraction of the rare earth element in the source solution was 0 at%, it was confirmed that only the soft magnetic properties of fcc-Co appeared. However, as can be seen from (a) and (b) of FIG. 17, when the molar fractions of rare earth elements in the source solution are 9.91 at% and 4.80 at%, the hard magnetic properties of Sm ₂ Co ₁₇ and fcc-Co It was confirmed that all the soft magnetic properties appeared.

18 is a graph showing the properties of a hybrid magnetic fiber according to a comparative example of the present invention in which no self-exchange coupling effect occurs.

Referring to FIG. 18, the Sm ₂ Co ₁₇ hard magnetic material and the fcc-Co soft magnetic material are simply mixed at a volume ratio of 50 vol%: 50 vol%. Applied field (kOe) of a hybrid magnetic fiber according to a comparative example of the present invention ) Shows the hysteresis curve by measuring Magnetization (emu/g). As can be seen in FIG. 18, the hybrid magnetic fibers according to Example 1, in which the volume fraction of the Sm ₂ Co ₁₇ magnetic crystal and the fcc-Co magnetic boundary layer was controlled to 50 vol%: 50 vol%, show that a kink phenomenon appears. , It was confirmed that the self-exchange coupling effect did not occur.

19 is a graph showing the effect of the volume fraction of the magnetic boundary layer on the magnetic properties of the hybrid magnetic fiber according to Example 1 of the present invention.

Referring to FIG. 19, the magnetic hysteresis curve was measured by measuring magnetization (emu/g) according to the applied field (Oe) of the hybrid magnetic fiber according to Example 1 in which the volume fraction of the fcc-Co magnetic boundary layer was controlled. As can be seen in FIG. 19, in the case of the hybrid magnetic fiber according to Example 1 of the present invention, unlike the hybrid magnetic fiber according to the comparative example shown in FIG. 18, the kink phenomenon does not appear in the magnetic hysteresis curve, and the self-exchange coupling effect It was confirmed that is generated.

In addition, the magnetic properties of the hybrid magnetic fibers according to Example 1 having different volume fractions of the fcc-Co magnetic boundary layer are summarized through <Table 5> below.

Volume fraction of Fcc-Co magnetic boundary layer
(vol %) Saturation magnetization
M _s (emu/g) Residual magnetization
M _r (emu/g) susceptibility
M _r /M _s (%) Coercive force
H _ci (Oe) Maximum magnetic energy
(BH) _max
(MGOe) 0 84.390 58.509 69.332 7044.6 7.001 0.3 88.176 60.696 68.835 6953.3 N/A One 87.265 59.559 68.251 6953.7 7.577 1.5 87.550 59.756 68.253 6741.5 N/A 3 87.887 58.706 66.797 6513.4 7.429 5 97.310 63.135 64.880 6193.0 7.208 7 98.377 62.070 63.094 5721.2 6.398 10 98.760 60.329 61.087 5128.0 6.010 20 99.444 54.478 54.783 3672.1 N/A 30 109.350 52.182 47.720 2526.2 N/A 50 124.670 47.231 37.885 1208.9 N/A 70 138.460 40.602 29.324 604.1 N/A 100 164.600 25.245 15.337 162.5 0.401

As can be seen through <Table 5>, the hybrid magnetic fiber according to Example 1 shows the highest maximum magnetic energy ((BH) _max ) value when the volume fraction of the fcc-Co magnetic boundary layer is 1 vol% I could confirm that. Accordingly, when the volume fraction of the fcc-Co magnetic boundary layer was 1 vol%, it was found that the effect of self-exchange coupling between the Sm ₂ Co ₁₇ magnetic crystal and the fcc-Co magnetic boundary layer was maximized.

Theoretically, in order to generate a magnetic exchange coupling force between the hard magnetic material and the soft magnetic material, the size of the soft magnetic material should be smaller than a value that is twice the domain-wall width of the magnetic domain boundary of the hard magnetic material. The theoretical size of the fcc-Co magnetic boundary layer required to exhibit the self-exchange coupling effect between the Sm ₂ Co ₁₇ magnetic crystal and the fcc-Co magnetic boundary layer is about 20.0 nm, which is less than about 5 at% when calculated by volume fraction. It can be seen that it is substantially consistent with the experimental data of the invention.

20 is a graph showing the effect of the volume fraction of magnetic crystals on the residual magnetization value of the hybrid magnetic fiber according to Example 1 of the present invention.

Referring to FIG. 20, the residual magnetization value (Remanence, M _r (emu/g)) of the hybrid magnetic fiber according to Example 1 in which the volume fraction of Sm ₂ Co ₁₇ magnetic crystals is controlled is illustrated. As can be seen in FIG. 20, when the volume fraction of the Sm ₂ Co ₁₇ magnetic crystal was 90 vol% or more, it was confirmed that the residual magnetization value was higher than the residual magnetization value of the Sm ₂ Co ₁₇ single phase.

21 is a graph showing the effect of the volume fraction of magnetic crystals on the maximum magnetic energy value of the hybrid magnetic fiber according to Example 1 of the present invention.

Referring to FIG. 21, the maximum magnetic energy value (Energy product, (BH) _max (MGOe)) of the hybrid magnetic fiber according to Example 1 in which the volume fraction of the Sm ₂ Co ₁₇ magnetic crystal is controlled is illustrated. As can be seen in FIG. 21, when the volume fraction of the Sm ₂ Co ₁₇ magnetic crystal was 99 vol%, it was confirmed that the maximum magnetic energy value was highest with 7.577 MGOe.

As can be seen through FIGS. 19 to 21, in the hybrid magnetic fiber according to Example 1, when the volume fraction of the fcc-Co magnetic boundary layer is greater than 0 vol% and less than 3 vol%, Sm ₂ Co ₁₇ magnetic crystals and fcc- It can be seen that the self-exchange coupling effect is easily generated between the Co magnetic boundary layers.

22 and 23 are graphs showing reformation of the Recoil curve of hybrid magnetic fibers according to Example 1 of the present invention, in which the volume fractions of the magnetic crystals and the magnetic crystal layers are different.

22 and 23, when the volume fraction of the Sm ₂ Co ₁₇ magnetic crystal and fcc-Co magnetic crystal layer is 97 vol%: 3 vol%, 95 vol%: 5 vol%, and 70 vol% : In case of 30 vol%, the magnetization (emu/g) according to the Applied Field (Oe) was measured, and the Recoil curve reformation was shown in FIGS. 22(a), 22(b), and 23. .

As can be seen from (a) and (b) of FIG. 22, when the volume fraction of the Sm ₂ Co ₁₇ magnetic crystal and the fcc-Co magnetic crystal layer is 97 vol%: 3 vol%, 95 vol%: 5 vol%. In the case of the hybrid magnetic fiber according to Example 1, it was confirmed that a closed loop appeared. On the other hand, as can be seen in Figure 23, Sm ₂ Co ₁₇ magnetic crystals and fcc-Co magnetic hybrid layer according to Example 1 when the volume fraction of the magnetic crystal layer is 70 vol%: 30 vol%, the open loop ( It was confirmed that the opened loop) appeared. In the case of a hybrid magnetic fiber in which a closed loop appears, a magnetic exchange coupling effect is exhibited between the Sm ₂ Co ₁₇ magnetic crystal and the fcc-Co magnetic crystal layer, but in the case of a hybrid magnetic fiber in which an open loop appears, Sm ₂ Co ₁₇ magnetic crystal and It means that there is no self-exchange bonding effect between the fcc-Co magnetic crystal layers.

24 is a graph showing Recoil susceptibility values of hybrid magnetic fibers according to Example 1 of the present invention having different volume fractions of the magnetic boundary layer.

Referring to FIG. 24, when the volume fraction of the fcc-Co magnetic boundary layer is more than 1 vol% (Co-excess-1), more than 3 vol% (Co-excess-3), and more than 5 vol% ( Co-excess-5), and for each of the hybrid magnetic fibers according to Example 1 above in the case of more than 30 vol% (Co-excess-30), dM/dH according to H(kOe) (emu/(g. Oe)) was measured to show the value of Recoil susceptibility.

As can be seen in Figure 24, the volume fraction of the fcc-Co magnetic boundary layer is more than 1 vol% (Co-excess-1), more than 3 vol% (Co-excess-3), and more than 5 vol% In the case (Co-excess-5), the hybrid magnetic fiber according to Example 1 was confirmed to have one peak. However, in the case where the volume fraction of the fcc-Co magnetic boundary layer is greater than 30 vol% (Co-excess-30), the hybrid magnetic fiber according to Example 1 above has two peaks at about -7 kOe and -2.5 kOe portions. It was confirmed that (peak) appeared. In the graph showing the value of recoil susceptibility, one peak means that a self-exchange bonding effect is exhibited between the Sm ₂ Co ₁₇ magnetic crystal and the fcc-Co magnetic crystal layer, and the two peaks are Sm ₂ Co ₁₇ magnetic crystal and fcc-. It means that the self-exchange bonding effect does not appear between the Co magnetic crystal layers.

25 to 27 are graphs comparing characteristics according to temperature to be heat-treated in the process of manufacturing a hybrid magnetic fiber according to Example 1 of the present invention.

25 to 27, the hybridization according to the first embodiment formed by controlling the temperature of the heat treatment in the reduction step of the preliminary hybrid magnetic fiber is controlled to 400 ℃, 500 ℃, 600 ℃, 700 ℃, 750 ℃, and 800 ℃ For each of the magnetic fibers, Relative intensity (au) according to 2theta (deg.) was measured to show an X-ray diffraction pattern. Hybrid magnetic fibers heat-treated at temperatures of 400°C, 500°C, 600°C, and 700°C are shown in FIG. 25, and hybrid magnetic fibers heat-treated at temperatures of 700°C, 750°C, and 800°C are shown in FIG. , An enlarged graph of part A of FIG. 26 is shown in FIG. 27.

As can be seen in Figures 25 to 27, when the temperature of the heat treatment in the reduction step is 400 ℃ and 500 ℃, the reduction of the rare earth oxide is not easily made, Sm ₂ Co ₁₇ magnetic crystal and fcc-Co magnetic crystal layer of It was confirmed that the mixed structure was not measured. In addition, when the temperature of the heat treatment in the reduction step is 800°C, it was also confirmed that the mixed structure of the Sm ₂ Co ₁₇ magnetic crystal and the fcc-Co magnetic crystal layer was not measured. On the other hand, when the temperature to be heat-treated in the reduction step is 600 ℃, 700 ℃ and 750 ℃, it was confirmed that the mixed structure of the Sm ₂ Co ₁₇ magnetic crystal and fcc-Co magnetic crystal layer is easily measured.

28 is a graph showing changes in properties according to the heat treatment temperature of the rare earth oxide.

Referring to FIG. 28, after the Sm ₂ O ₃ rare earth oxide is heat treated at 25° C. to 1000° C. at a heating rate of 10° C./mim in a hydrogen atmosphere, the mass loss (%) of the heat treated rare earth oxide is measured. It was measured and indicated. As can be seen in FIG. 28, it was confirmed that, even in the case of a rare earth oxide, even when heat-treated at a temperature of 1000° C., there was almost no mass loss and reduction was not easily achieved.

29 to 31 are photographs and graphs comparing the diameters of the hybrid magnetic fibers according to Examples 1 and 3 of the present invention.

Referring to FIG. 29, the SEM of the hybrid magnetic fiber according to Example 3 is shown in FIG. 29(a), and the diameter of the hybrid magnetic fiber is measured and illustrated in FIG. 29( b). As can be seen from (a) and (b) of FIG. 29, it was confirmed that the hybrid magnetic fibers according to Example 3 had a diameter of 250 nm or less and a chain structure.

30 and 31, SEM photographs of the hybrid magnetic fibers according to Example 1 having a diameter of about 500 nm and a diameter of about 1000 nm are shown in FIGS. 30(a) and 31(a), respectively. , Measuring the diameter of each hybrid magnetic fiber is shown in Figure 30 (b) and Figure 31 (b). As can be seen in FIGS. 30 and 31, it was confirmed that the hybrid magnetic fibers according to Example 1 having a diameter of about 500 nm and a diameter of about 1000 nm have a magnetic crystal-magnetic boundary layer structure.

As described above, the present invention has been described in detail using preferred embodiments, but the scope of the present invention is not limited to specific embodiments, and should be interpreted by the appended claims. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

10: syringe
20: syringe pump
30: syringe tip
40: Collector
100: hybrid magnetic fiber
110: magnetic determination
120: magnetic boundary layer

Claims (14)

Preparing a source solution comprising a first source material comprising a rare earth element and a second source material comprising a transition metal element;
Electrospinning the source solution to form a preliminary hybrid magnetic fiber comprising a rare earth oxide and a transition metal oxide; And
Reducing the preliminary hybrid magnetic fiber, comprising a compound of the rare earth element and the transition metal element and having a hard-magnetic property, a magnetic crystal, and the transition metal element containing soft magnetic ( and forming a hybrid magnetic fiber including a magnetic boundary layer having soft-magnetic properties,
The hybrid magnetic fiber, a hybrid magnetic fiber manufacturing method comprising a plurality of the magnetic crystal and the magnetic boundary layer having a fiber shape extending in one direction.
delete According to claim 1,
The magnetic boundary layer, the method comprising the following magnetization behavior of the magnetic crystals, hybrid magnetic fiber manufacturing method.
According to claim 1,
A method of manufacturing a hybrid magnetic fiber, wherein the molar fraction of the rare earth element in the source solution is greater than 9.290 at% and less than 10.562 at%.
According to claim 1,
The hybrid magnetic fiber forming step,
Mixing the preliminary hybrid magnetic fiber with a reducing agent;
Heat-treating the preliminary hybrid magnetic fiber mixed with the reducing agent; And
Method of manufacturing a hybrid magnetic fiber, comprising the step of washing the heat-treated preliminary hybrid magnetic fiber with a washing solution.
The method of claim 5,
The preliminary hybrid magnetic fiber mixed with the reducing agent, the method comprising the heat treatment at a temperature of less than 800 ℃ more than 500 ℃, hybrid magnetic fiber manufacturing method.
The method of claim 5,
The reducing agent is a hybrid magnetic fiber manufacturing method comprising calcium (Ca).
The method of claim 5,
The washing solution, hybrid magnetic fiber production method comprising at least one of ammonium chloride (NH ₄ Cl), and methanol (CH ₃ OH).
According to claim 1,
The source solution, hybrid magnetic fiber manufacturing method further comprises a crystallization source containing a metal, and a viscous source comprising a polymer.
According to claim 1,
The rare earth element, any one of La, Ce, Pr, Nd, Sm, or Gd, hybrid magnetic fiber manufacturing method.
According to claim 1,
The transition metal element, any one of Fe, Co, or Ni, hybrid magnetic fiber manufacturing method.
A plurality of magnetic crystals comprising a compound of a rare earth element and a transition metal element and having hard magnetic properties; And
Disposed between the magnetic crystals adjacent to each other, surrounding the magnetic crystals,
It includes the transition metal element, and includes a magnetic boundary layer (magnetic boundary layer) having soft magnetic properties,
A hybrid magnetic fiber comprising a plurality of the magnetic crystals and the magnetic boundary layer having a fiber shape extending in one direction.
The method of claim 12,
In the hybrid magnetic fiber, the volume fraction of the magnetic boundary layer includes more than 0 vol% and less than 10 vol%, the hybrid magnetic fiber.
The method of claim 12,
The magnetic boundary layer includes a hybrid magnetic fiber that includes following the magnetization behavior of the magnetic crystal.

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