WO2020111386A1 - Iron nitride magnetic wire and manufacturing method therefor - Google Patents

Abstract

A method for manufacturing a magnetic wire is provided. The method for manufacturing a magnetic wire can comprise the steps of: forming a first preliminary magnetic wire by electrospinning a source solution comprising Fe; forming a second preliminary magnetic wire comprising Fe oxide by performing heat treatment on the first preliminary magnetic wire at a first temperature; performing heat treatment on the second preliminary magnetic wire at a second temperature, thereby forming a third preliminary magnetic wire in which Fe oxide is reduced; and performing, at a third temperature, heat treatment on the third preliminary magnetic wire in a source gas atmosphere comprising nitrogen, thereby forming a magnetic wire in which nitrogen penetrates the third preliminary magnetic wire.

Description

Iron nitride magnetic wire and its manufacturing method

The name relates to an iron nitride magnetic wire and a manufacturing method thereof, and relates to an iron nitride magnetic wire using a source solution containing Fe and a manufacturing method thereof.

Permanent magnets are a key material in industries that are widely used, from large equipment such as generators to small and medium equipment such as motors. In particular, permanent magnets used in motors and generators are functional materials that play a key role in converting electrical energy into kinetic energy. Recently, the production and demand of eco-friendly vehicles has rapidly increased due to the importance of replacing petroleum energy and low-carbon green growth, and the increase in the use of these motors has led to high efficiency, light weight, and miniaturization of motors, resulting in an explosive increase in the demand for rare earth permanent magnet materials. .

Rare earth-based permanent magnet materials show very high magnetic properties at room temperature, but have reached the theoretical maximum magnetic energy properties, and due to low thermal stability, a rapid decrease in properties occurs as the temperature increases. To overcome these drawbacks, heavy rare earth elements are added, but due to the unbalanced distribution of rare earth resources and the high price due to resource atomization, the high maximum magnetic energy of reducing or reducing rare earth elements in existing rare earth magnets or containing new rare earth elements Research is being conducted to find permanent magnet materials with enemies.

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 including a thin film laminate obtained by repeatedly laminating and heat-treating units at least twice or more and a method for manufacturing the same.

One technical problem to be solved by the present invention is to provide an iron nitride magnetic wire with improved saturation magnetization value and a method for manufacturing the same.

Another technical problem to be solved by the present invention is to provide an iron nitride magnetic wire with improved coercive force and a method for manufacturing the same.

Another technical problem to be solved by the present invention is to provide an iron nitride magnetic wire capable of improving magnetic properties in a simple process and a method of 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-described technical problems, the present invention provides a magnetic wire manufacturing method.

According to one embodiment, the method of manufacturing the magnetic wire is electrospinning a source solution containing Fe to form a first preliminary magnetic wire, and heat-treating the first preliminary magnetic wire at a first temperature to generate Fe oxide. Forming a second preliminary magnetic wire, heat-treating the second preliminary magnetic wire at a second temperature to form a third preliminary magnetic wire with reduced Fe oxide, and the third preliminary magnetic wire , Heat-treating at a source gas atmosphere containing nitrogen and a third temperature to form a magnetic wire in which nitrogen is penetrated into the third preliminary magnetic wire,

It may include controlling the saturation magnetization value of the magnetic wire by controlling at least one of the first to third temperatures.

According to one embodiment, the first temperature may include more than 600 ℃ less than 800 ℃.

According to an embodiment, in the forming of the magnetic wire, a nitrogen atom (atom) decomposed from the source gas is penetrated into the magnetic wire, and the infiltrated nitrogen atom includes bonding with Fe included in the magnetic wire. can do.

According to an embodiment, the saturation magnetization value may be controlled by controlling the flow rate of the source gas provided in the forming of the magnetic wire.

According to one embodiment, the source gas may include that provided at a flow rate of 1.5 L/min or more.

According to an embodiment, the forming of the second preliminary magnetic wire may include performing in one of an atmosphere or an oxygen (O ₂ ) atmosphere.

According to an embodiment, the second temperature and the third temperature may include lower than the first temperature.

According to an embodiment, the source gas may include ammonia (NH ₃ ).

According to one embodiment, as the first temperature increases, it may include that the grain size of the magnetic wire increases.

According to an embodiment, the second preliminary magnetic wire may include Fe ₂ O ₃ , the third preliminary magnetic wire may include α-Fe, and the magnetic wire may include Fe ₁₆ N ₂ .

In order to solve the above-described technical problems, the present invention provides a magnetic wire.

According to an embodiment, the magnetic wire includes iron (Fe) and iron nitride (Fe _x N _y ), but the content of the iron nitride may be higher than the content of the iron. (x,y>0)

According to one embodiment, the iron nitride (Fe _x N _y ) may include more than 88.7wt%.

According to an embodiment, x may include 16 and y may include 2.

A method of manufacturing a magnetic wire according to an embodiment of the present invention comprises: electrospinning a source solution containing Fe to form a first preliminary magnetic wire, and heat-treating the first preliminary magnetic wire at a first temperature to Fe oxide. Forming a second preliminary magnetic wire comprising, heat-treating the second preliminary magnetic wire at a second temperature to form a third preliminary magnetic wire with reduced Fe oxide, and the third preliminary magnetic wire. , Heat-treating at a source gas atmosphere containing nitrogen and a third temperature to form a magnetic wire in which nitrogen is penetrated into the third preliminary magnetic wire, wherein at least one of the first to third temperatures is included. By controlling, it may include controlling the saturation magnetization value.

That is, the magnetic wire manufacturing method according to the embodiment is a simple method for controlling the temperature of the heat treatment step, and increases the content of the iron nitride (Fe ₁₆ N ₂ ) contained in the magnetic wire, thereby improving the saturation magnetization value. I can do it. In addition, the magnetic wire according to the embodiment may have a wire shape. In the case of the wire form, as it has a high aspect ratio, it can exhibit a shape magnetic anisotropy effect. Such a shape magnetic anisotropy effect can lead to an improvement in the coercive force. As a result, iron nitride (Fe ₁₆ N ₂ ) wire having a saturation magnetization value of 176 emu/g or more and a coercive force of 1215 Oe or more, and a method of manufacturing the same can be provided.

1 is a flowchart illustrating a method of manufacturing a magnetic wire according to an embodiment of the present invention.

2 is a view showing a magnetic wire manufacturing process according to an embodiment of the present invention.

3 is a view showing equipment used in the manufacture of a magnetic wire according to an embodiment of the present invention.

4 is a view showing a nitrogen penetration phenomenon in a method of manufacturing a magnetic wire according to an embodiment of the present invention.

5 is a view for explaining the coercive force of the magnetic wire according to an embodiment of the present invention.

6 is a photograph of the first preliminary magnetic wire formed during the manufacturing process of the magnetic wire according to the first embodiment of the present invention.

7 and 8 are photographs of the first preliminary magnetic wire formed during the manufacturing process of the magnetic wire according to Comparative Example 1 and Comparative Example 2 of the present invention.

9 is a photograph of the first preliminary magnetic wire formed during the manufacturing process of the magnetic wire according to Example 2 of the present invention.

10 to 12 are photographs of a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to the first embodiment of the present invention.

13 to 15 are photographs of a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to the second embodiment of the present invention.

16 to 18 are photographs of a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to Example 3 of the present invention.

19 to 21 are photographs of a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to Example 4 of the present invention.

22 and 23 are photographs of magnetic wires according to Examples 9 to 12 of the present invention.

24 is a graph analyzing the components of each of the second preliminary magnetic wire, the third preliminary magnetic wire, and the magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to Example 2 of the present invention.

25 and 26 are graphs showing a characteristic change according to the heat treatment temperature of the first preliminary magnetic wire during the manufacturing process of the magnetic wire according to the embodiment of the present invention.

27 is a graph analyzing the components of the magnetic wires according to Examples 1 to 4 of the present invention.

28 is a graph analyzing the components of the magnetic wires according to Examples 9 to 12 of the present invention.

29 to 32 are graphs showing characteristics of the second preliminary magnetic wire formed during the manufacturing process of the magnetic wires according to Examples 1 to 4 of the present invention.

33 is a graph analyzing components of magnetic wires according to Examples 2, 5, and 6 of the present invention.

34 is a graph analyzing the components of the magnetic wires according to Examples 6, 7, and 8 of the present invention.

35 is a graph showing a configuration change according to a flow rate of ammonia gas in a manufacturing process of a magnetic wire according to an embodiment of the present invention.

36 is a graph showing magnetic properties of a magnetic wire according to Example 6 of the present invention.

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 of the presence or addition of elements or combinations thereof. In addition, in the present 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 flow chart illustrating a method of manufacturing a magnetic wire according to an embodiment of the present invention, Figure 2 is a view showing a magnetic wire manufacturing process according to an embodiment of the present invention, Figure 3 is according to an embodiment of the present invention FIG. 4 is a diagram showing equipment used in the manufacture of a magnetic wire, and FIG. 4 is a diagram showing a nitrogen infiltration phenomenon in a method of manufacturing a magnetic wire according to an embodiment of the present invention, and FIG. 5 is a magnetic wire according to an embodiment It is a view for explaining the coercive force of.

1 to 3, a source solution containing Fe may be prepared. According to one embodiment, the source solution may include iron nitrate hexahydrate (Iron(III) nitrate nonahydrate, Fe(NO ₃ ) ₃ 9H ₂ O). The source solution may further include a viscous source. 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 can provide viscosity to the source solution to control the diameter of the magnetic wire to be described later.

The source solution is electrospinned, so that the first preliminary magnetic wire 110 may be formed (S110). The first preliminary magnetic wire 110 may be in a state in which a Fe salt and a polymer (eg, PVP) are mixed.

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 a diameter of 0.05 to 2 mm, the syringe tip 30 and the collector 40 to which the preliminary hybrid magnetic fibers are collected are spaced 15 cm apart, and the syringe pump 20 Can release the source solution at a rate of 0.2 to 0.8 mL/h. In addition, the voltage applied for electric radiation may be 16-20 kV. The first preliminary magnetic wire may be formed through the above-described process.

The first preliminary magnetic wire 110 may be heat treated at a first temperature. Accordingly, the second preliminary magnetic wire 120 may be formed (S120). In addition, the first preliminary magnetic wire 110 may be heat-treated in one of an atmosphere (air) atmosphere or an oxygen (O ₂ ) atmosphere. When the first preliminary magnetic wire 110 is heat-treated at the first temperature, polymers and organic substances included in the first preliminary magnetic wire 110 are removed, and Fe may be oxidized. Accordingly, the second preliminary magnetic wire 120 may include Fe oxide. For example, the second preliminary magnetic wire 120 may include Fe ₂ O ₃ .

According to one embodiment, the first temperature may be controlled. In addition, the first temperature may be different depending on the heat treatment atmosphere of the first preliminary magnetic wire 110. Specifically, when the first preliminary magnetic wire 110 is heat-treated in an oxygen (O ₂ ) atmosphere, the first temperature may be controlled to 600°C. In this case, the content of iron nitride (Fe ₁₆ N ₂ ) in the magnetic wire to be described later increases, so that the saturation magnetization value of the magnetic wire can be improved. More detailed description will be given later.

On the other hand, when the first preliminary magnetic wire 110 is heat-treated in an air atmosphere, the first temperature may be controlled to be greater than 600°C and less than 800°C. In this case, the content of iron nitride (Fe ₁₆ N ₂ ) in the magnetic wire to be described later increases, so that the saturation magnetization value of the magnetic wire can be improved.

Alternatively, when the first temperature is controlled to 600° C. or less, the removal of organic substances and polymers in the first preliminary magnetic wire 110 is not easily performed, and thus the formation of a magnetic wire described later may not be easy. . In addition, when the first temperature is controlled to 800° C. or higher, a grain size of the magnetic wire to be described later increases, which may cause a problem of forming in a particle shape rather than a wire shape. That is, the magnetic wire to be described later may increase the size of the crystal grains as the first temperature increases, and when the size of the crystal grains exceeds a predetermined size, may exhibit a particle shape. Accordingly, the first temperature may be controlled so that the grain size of the magnetic wire does not exceed a predetermined size.

The second preliminary magnetic wire 120 may be heat treated at a second temperature. In addition, the second preliminary magnetic wire 120 may be heat treated in a hydrogen (H ₂ ) atmosphere. Accordingly, the Fe oxide included in the first preliminary magnetic wire 110 is reduced, and a third preliminary magnetic wire 130 may be formed (S130 ). For example, the third preliminary magnetic wire 130 may include α-Fe.

According to one embodiment, the second temperature may be controlled. The second temperature may be lower than the first temperature. Specifically, the second temperature can be controlled to 290 ℃. In this case, the content of iron nitride (Fe ₁₆ N ₂ ) in the magnetic wire to be described later increases, so that the saturation magnetization value of the magnetic wire can be improved.

The third preliminary magnetic wire 130 may be heat treated at a third temperature in a source gas atmosphere containing nitrogen. Accordingly, the magnetic wire 200 according to the embodiment may be formed (S140). According to one embodiment, the source gas may include ammonia (NH ₃ ).

When the third preliminary magnetic wire 130 is heat-treated in the source gas atmosphere, nitrogen atoms (atom, N) decomposed from the source gas may be penetrated into the magnetic wire 200 as illustrated in FIG. 4. Can be. The penetrated nitrogen atom may be combined with Fe included in the magnetic wire 200. Accordingly, the magnetic wire 200 may include iron nitride (Fe _x N _y ) in which a nitrogen atom and Fe are bonded. As a result, the magnetic wire may include the iron nitride (Fe _x N _y ), and the iron (Fe) remaining unbound with nitrogen. (x,y>0) For example, the iron nitride (Fe _x N _y ) may be Fe ₁₆ N ₂ .

In the case of the iron nitride (Fe ₁₆ N ₂ ), a high saturation magnetization value may be exhibited due to the properties of the material. Accordingly, when the iron nitride (Fe ₁₆ N ₂ ) content in the magnetic wire increases, the saturation magnetization value of the magnetic wire may be improved. As described above, the content of iron nitride (Fe ₁₆ N ₂ ) in the magnetic wire is the first temperature in the step of forming the second preliminary magnetic wire 120, and the third preliminary magnetic wire 130 is formed. It can be increased by controlling the second temperature in the step. That is, as a simple method of controlling the first temperature and the second temperature, the content of iron nitride (Fe ₁₆ N ₂ ) in the magnetic wire is increased, so that the saturation magnetization value of the magnetic wire 200 may be improved.

According to an embodiment, the flow rate of the source gas provided to the third preliminary magnetic wire 130 may be controlled. For example, the source gas may be provided at a flow rate of 1.5 L/min or more. Accordingly, the content of the iron nitride (Fe ₁₆ N ₂ ) included in the magnetic wire is increased, so that the saturation magnetization value can be improved.

More specifically, when the ammonia (NH ₃ ) gas is provided to the third preliminary magnetic wire 130, due to the temperature and the catalytic effect of the Fe surface, the ammonia gas is a nitrogen atom, as shown in <Formula 1> below. It can be decomposed into hydrogen atoms. Then, the decomposed nitrogen atom and the hydrogen atom may be formed in a nitrogen molecular state as shown in <Formula 2> below.

<Formula 1>

2NH ₃ ->2N+6H

<Formula 2>

2N+6H->N ₂ +3H ₂

As described above, the iron nitride (Fe ₁₆ N ₂ ) may be formed by combining nitrogen in the atomic state with Fe. However, in the case of a nitrogen atom decomposed from ammonia (NH ₃ ) gas, a nitrogen molecule is formed over time, and in the case of a nitrogen molecule, it may not be combined with Fe. Accordingly, by increasing the flow rate of the source gas provided to the third preliminary magnetic wire 130 to increase the amount of nitrogen atoms that can be combined with Fe, the magnetic wire 200 includes the The content of iron nitride (Fe ₁₆ N ₂ ) can be increased. However, when the flow rate of the source gas exceeds a predetermined flow rate, the amount of nitrogen atoms bound to Fe is saturated, so that the content of the iron fine iron (Fe ₁₆ N ₂ ) included in the magnetic wire 200 is It can remain substantially the same. As a result, as the ammonia (NH ₃ ) gas is provided at a flow rate of 1.5 L/min or higher, the content of the iron nitride (Fe ₁₆ N ₂ ) included in the magnetic wire 200 is increased to improve the saturation magnetization value. I can do it.

According to one embodiment, the third temperature may be controlled. The third temperature may be lower than the first and second temperatures. Specifically, the third temperature can be controlled to 160 ℃. In this case, the content of iron nitride (Fe ₁₆ N ₂ ) in the magnetic wire 200 increases, so that the saturation magnetization value of the magnetic wire 200 may be improved.

According to one embodiment, the third preliminary magnetic wire forming step (S130), and the magnetic wire forming step (S140) may be performed in an in-situ process. In this case, formation of contaminants and oxide layers on the surface of the third preliminary magnetic wire can be suppressed. Accordingly, the magnetic wire can be easily formed.

In the case of the conventional magnetic structure containing iron nitride (Fe ₁₆ N ₂ ), it was manufactured in the form of nanoparticles. Specifically, iron nitride (Fe ₁₆ N ₂ ) nanoparticles were prepared by providing ammonia (NH ₃ ) gas to an Fe powder, and in this process, an oxide film was formed on the surfaces of Fe particles to form nitrogen. A problem that penetration of the product is not easily generated may occur. In addition, in the case of magnetic nanoparticles including iron nitride (Fe ₁₆ N ₂ ), as illustrated in FIG. 5, aggregation may occur between particles to reduce surface energy. Such agglutination may cause magnetostain coupling and intergranulae exchange coupling between particles, and may act as a major cause of reducing coercive force.

That is, iron nitride (Fe ₁₆ N ₂₎ If the magnetic nanoparticles (particle) containing iron nitride (Fe ₁₆ N ₂₎ exhibits a high saturation magnetization due to inherent material properties, due to specific aggregation particles A problem that the coercive force is lowered may occur. In addition, in the process of manufacturing iron nitride (Fe ₁₆ N ₂ ) magnetic nanoparticles, the penetration of nitrogen is not easily generated, and a problem that iron nitride (Fe ₁₆ N ₂ ) is not easily formed may occur.

However, in the method of manufacturing a magnetic wire according to an embodiment of the present invention, the source solution containing Fe is electrospun to form the first preliminary magnetic wire 110, and the first preliminary magnetic wire 110 is formed. Heat-treating at a first temperature to form the second preliminary magnetic wire 120 including Fe oxide, and heat-treating the second preliminary magnetic wire 120 at a second temperature to reduce the Fe oxide. 3 forming a preliminary magnetic wire, and heat-treating the third preliminary magnetic wire 130 in a source gas atmosphere containing nitrogen and a third temperature, so that nitrogen penetrates into the third preliminary magnetic wire 130. The step of forming the magnetic wire 200 may include, but may include controlling a saturation magnetization value by controlling at least one of the first to third temperatures.

That is, the magnetic wire manufacturing method according to the embodiment is a simple method of controlling the temperature of the heat treatment step, and increases the content of the iron nitride (Fe ₁₆ N ₂ ) contained in the magnetic wire 200 to increase the saturation magnetization. The value can be improved. In addition, the magnetic wire 200 according to the embodiment may have a wire shape. In the case of the wire form, as it has a high aspect ratio, it can exhibit a shape magnetic anisotropy effect. Such a shape magnetic anisotropy effect can lead to an improvement in the coercive force. In addition, as shown in FIG. 5, in the case of a wire form, nitrogen penetration can be easily generated, so that the content of iron nitride (Fe ₁₆ N ₂ ) can be increased. As a result, iron nitride (Fe ₁₆ N ₂ ) wire having a saturation magnetization value of 176 emu/g or more and a coercive force of 1215 Oe or more, and a method of manufacturing the same can be provided.

In the above, the magnetic wire according to the embodiment of the present invention and a manufacturing method thereof have been described. Hereinafter, specific experimental examples and characteristic evaluation results of the magnetic wire and the manufacturing method according to the above-described embodiment will be described.

Preparation of magnetic wire according to Example 1

Iron(III) nitrate nonahydrate, Fe(NO ₃ ) ₃ 9H ₂ O), 1,300,000 molecular weight polyvinylpyrrolidone (PVP), and 6 ml of ethanol were added to 3 ml of deionized water. The source solution was prepared by mixing. At this time, the concentration of PVP was prepared at 3.4 wt% compared to the source solution.

The prepared source solution is placed in a syringe for electrospinning, and the solution is continuously pushed at a rate of 0.4 mL/h using a syringe pump. At this time, the tip portion of the syringe and the collector where the emitted wire is collected are spaced at 15 cm intervals, and a high voltage of 18 kV is applied to radiate the source solution by a potential difference. Thus, a first preliminary magnetic wire was produced.

The first preliminary magnetic wire was collected in an alumina (Al ₂ O ₃ ) crucible and heat-treated at an air temperature of 600° C. for 1 hour. In this process, polymers and organic substances in the first preliminary magnetic wire were decomposed to produce a second preliminary magnetic wire.

The second preliminary magnetic wire was heat-treated at a temperature of 320° C. in a hydrogen (H ₂ ) atmosphere. In this process, Fe oxide in the second preliminary magnetic wire was reduced to produce a third preliminary magnetic wire.

The third preliminary magnetic wire was heat-treated at a temperature of 160°C in an ammonia (NH ₃ ) gas atmosphere. In this process, nitrogen atoms decomposed from the ammonia gas penetrated into the third preliminary magnetic wire to form Fe ₁₆ N ₂ iron nitride. As a result, a magnetic wire according to Example 1 including Fe ₁₆ N ₂ iron nitride and Fe was prepared.

Preparation of magnetic wire according to Example 2

Prepared by the method of manufacturing the magnetic wire according to Example 1, the temperature of the heat treatment in the process of manufacturing the second preliminary magnetic wire was controlled to 700°C. Thus, a magnetic wire according to Example 2 was produced.

Preparation of magnetic wire according to Example 3

Prepared by the manufacturing method of the magnetic wire according to Example 1, the temperature of the heat treatment in the process of manufacturing the second preliminary magnetic wire was controlled to 800°C. Thus, a magnetic wire according to Example 3 was produced.

Preparation of magnetic wire according to Example 4

Prepared by the manufacturing method of the magnetic wire according to Example 1, the temperature of heat treatment in the process of manufacturing the second preliminary magnetic wire was controlled to 900°C. Thus, a magnetic wire according to Example 4 was produced.

Preparation of magnetic wire according to Example 5

Prepared by the method of manufacturing the magnetic wire according to Example 1, the temperature of the heat treatment in the process of manufacturing the second preliminary magnetic wire was controlled to 700°C. In addition, the temperature to be heat-treated in the process of manufacturing the third preliminary magnetic wire was controlled to 305°C. Thus, a magnetic wire according to Example 5 was produced.

Preparation of magnetic wire according to Example 6

Prepared by the method of manufacturing the magnetic wire according to Example 1, the temperature of the heat treatment in the process of manufacturing the second preliminary magnetic wire was controlled to 700°C. In addition, the temperature to be heat-treated in the process of manufacturing the third preliminary magnetic wire was controlled to 290°C. Thus, a magnetic wire according to Example 6 was produced.

Preparation of magnetic wire according to Example 7

Prepared by the method of manufacturing the magnetic wire according to Example 1, the temperature of the heat treatment in the process of manufacturing the second preliminary magnetic wire was controlled to 700°C. In addition, the temperature to be heat-treated in the process of manufacturing the third preliminary magnetic wire was controlled to 290°C. In addition, in the process of heat-treating the third preliminary magnetic wire with ammonia gas, the heat treatment temperature was controlled to 150°C. Thus, a magnetic wire according to Example 7 was produced.

Preparation of magnetic wire according to Example 8

Prepared by the method of manufacturing the magnetic wire according to Example 1, the temperature of the heat treatment in the process of manufacturing the second preliminary magnetic wire was controlled to 700°C. In addition, the temperature to be heat-treated in the process of manufacturing the third preliminary magnetic wire was controlled to 290°C. In addition, in the process of heat-treating the third preliminary magnetic wire with ammonia gas, the heat treatment temperature was controlled to 140°C. Thus, a magnetic wire according to Example 8 was produced.

Preparation of magnetic wire according to Example 9

Prepared by the manufacturing method of the magnetic wire according to Example 1, the conditions of heat treatment in the process of manufacturing the second preliminary magnetic wire were controlled in an oxygen (O ₂ ) atmosphere. Thus, a magnetic wire according to Example 9 was produced.

Preparation of magnetic wire according to Example 10

Prepared by the manufacturing method of the magnetic wire according to Example 1, the conditions of heat treatment in the process of manufacturing the second preliminary magnetic wire were controlled in an oxygen (O ₂ ) atmosphere, and the heat treatment temperature was controlled at 700°C. Thus, a magnetic wire according to Example 10 was produced.

Preparation of magnetic wire according to Example 11

Prepared by the manufacturing method of the magnetic wire according to Example 1, the second preliminary magnetic wire was controlled in an oxygen (O ₂ ) atmosphere, and the heat treatment temperature was controlled to 800° C. under conditions of heat treatment in the process of manufacturing. Thus, a magnetic wire according to Example 11 was prepared.

Preparation of magnetic wire according to Example 12

Prepared by the manufacturing method of the magnetic wire according to Example 1, the conditions of heat treatment in the process of manufacturing the second preliminary magnetic wire were controlled in an oxygen (O ₂ ) atmosphere, and the heat treatment temperature was controlled at 900°C. Thus, a magnetic wire according to Example 12 was produced.

Preparation of magnetic wire according to Comparative Example 1

Prepared by the method of manufacturing the magnetic wire according to Example 1, the concentration of PVP in the process of preparing the source solution was controlled to be 2.1 wt% compared to the source solution. In addition, in the process of preparing the source solution, citric acid at a concentration of 0.5 M was further added. Thus, a magnetic wire according to Comparative Example 1 was produced.

Preparation of magnetic wire according to Comparative Example 2

Prepared by the method of manufacturing the magnetic wire according to Example 1, the concentration of PVP in the process of preparing the source solution was controlled to be 2.0 wt% compared to the source solution. Thus, a magnetic wire according to Comparative Example 2 was produced.

The characteristics of the magnetic wire according to the above-described embodiments and comparative examples are summarized through <Table 1> below.

division	PVP concentration in source solution	First preliminary magnetic wire heat treatment atmosphere	First pre-magnetic wire heat treatment temperature	Second pre-magnetic wire heat treatment temperature	Third pre-magnetic wire heat treatment temperature
Example 1	3.4 wt%		Air	600℃	320℃	160℃
Example 2	3.4 wt%		Air	700℃	320℃	160℃
Example 3	3.4 wt%		Air	800℃	320℃	160℃
Example 4	3.4 wt%	Air	900℃	320℃	160℃
Example 5	3.4 wt%		Air	700℃	305℃	160℃
Example 6	3.4 wt%		Air	700℃	290℃	160℃
Example 7	3.4 wt%		Air	700℃	290℃	150℃
Example 8	3.4 wt%		Air	700℃	290℃	140℃
Example 9	3.4 wt%	Oxygen (O 2 )	600℃	320℃	160℃
Example 10	3.4 wt%	Oxygen (O 2 )	700℃	320℃	160℃
Example 11	3.4 wt%	Oxygen (O 2 )	800℃	320℃	160℃
Example 12	3.4 wt%	Oxygen (O 2 )	900℃	320℃	160℃
Comparative Example 1	2.1 wt%		Air	700℃	320℃	160℃
Comparative Example 2	2.0 wt%		Air	700℃	320℃	160℃

6 is a photograph of the first preliminary magnetic wire formed during the manufacturing process of the magnetic wire according to the first embodiment of the present invention.

Referring to FIG. 6, a magnetic wire according to Example 1 was prepared, but a first preliminary magnetic wire formed through electrospinning of the source solution during the manufacturing process of the magnetic wire was photographed by SEM (Scanning Electron Microscope). As can be seen from FIG. 6, it was confirmed that the first preliminary magnetic wire has a wire shape.

7 and 8 are photographs of the first preliminary magnetic wire formed during the manufacturing process of the magnetic wire according to Comparative Example 1 and Comparative Example 2 of the present invention.

7 and 8, a magnetic wire according to Comparative Example 1 and Comparative Example 2 was prepared, but the first preliminary magnetic wire formed through electrospinning of the source solution during the manufacturing process of the magnetic wire was SEM photographed. (A) and (b) of each drawing show photographs of different magnifications. 7 and 8, it was confirmed that a plurality of beads were formed in the first preliminary magnetic wire formed during the manufacturing process of the magnetic wires according to Comparative Example 1 and Comparative Example 2. In this case, a problem that the final magnetic wire cannot be easily formed by the bead may occur.

9 is a photograph of the first preliminary magnetic wire formed during the manufacturing process of the magnetic wire according to Example 2 of the present invention.

Referring to FIG. 9, the magnetic wire according to Example 2 was prepared, but the first preliminary magnetic wire formed through electrospinning of the source solution during the manufacturing process of the magnetic wire was SEM photographed. 9(a) and 9(b) show photographs of different magnifications. As can be seen in Figure 9, it was confirmed that the first preliminary magnetic wire formed during the manufacturing process of the magnetic wire according to Example 2 was formed in a wire shape having a constant thickness without forming a bead.

That is, as can be seen through FIGS. 6 to 9, during the manufacturing process of the magnetic wire according to the above embodiment, it was found that the PVP content in the source solution can affect the production of the final magnetic wire.

10 to 12 are photographs of a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to the first embodiment of the present invention.

10 to 12, by performing the manufacturing process of the magnetic wire according to the first embodiment, to prepare a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire, each SEM photographed to FIG. 10 , FIGS. 11 and 12. (A) and (b) of each drawing show photographs of different magnifications.

10 to 12, while the manufacturing process of the magnetic wire according to the first embodiment is performed, it is confirmed that the second preliminary magnetic wire, the third preliminary magnetic wire, and the magnetic wire are all formed in the form of a wire. Could. In addition, it was confirmed that the prepared magnetic wire had a diameter of 100 to 300 nm, and a length of 10 μm or more.

13 to 15 are photographs of a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to the second embodiment of the present invention.

13 to 15, by performing the manufacturing process of the magnetic wire according to the second embodiment, to prepare a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire, each SEM photographed to FIG. 13 , FIGS. 14 and 15. (A) and (b) of each drawing show photographs of different magnifications.

13 to 15, while the manufacturing process of the magnetic wire according to the first embodiment is performed, it is confirmed that the second preliminary magnetic wire, the third preliminary magnetic wire, and the magnetic wire are all formed in the form of wires. Could. In addition, it was confirmed that the prepared magnetic wire had a diameter of 100 to 300 nm, and a length of 10 μm or more.

16 to 18 are photographs of a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to Example 3 of the present invention.

16 to 18, by performing the manufacturing process of the magnetic wire according to Example 3, to prepare a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire, each of which is SEM photographed to FIG. 16 , FIGS. 17 and 18. (A) and (b) of each drawing show photographs of different magnifications.

16 to 18, while the manufacturing process of the magnetic wire according to the third embodiment is performed, it is confirmed that the second preliminary magnetic wire, the third preliminary magnetic wire, and the magnetic wire are all formed in the form of a wire. Could. In addition, it was confirmed that the prepared magnetic wire had a diameter of 100 to 300 nm, and a length of 10 μm or more.

19 to 21 are photographs of a second preliminary magnetic wire, a third preliminary magnetic wire, and a magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to Example 4 of the present invention.

19 to 21, the second preliminary magnetic wire, the third preliminary magnetic wire, and the magnetic wire formed during the process of manufacturing the magnetic wire according to Example 4 are all exhibiting coarsening of particles. I could confirm. In addition, it was confirmed that the magnetic wire according to Example 4 was formed closer to the particle shape than the wire shape.

Crystallite sizes of the magnetic wires according to Examples 1 to 4 identified through FIGS. 10 to 21 are summarized through Table 2 below.

division	Crystallite size (nm)
Example 1	14.3
Example 2	18.5
Example 3	26.2
Example 4	16.7

That is, as can be seen through FIGS. 10 to 21 and <Table 2>, during the process of manufacturing the magnetic wire according to the embodiment, the first pre-heating temperature of the magnetic wire is 600°C, 700°C, 800°C, and As it was increased to 900°C, it was confirmed that the particle size of the magnetic wire finally formed increased. In addition, when the heat treatment temperature of the first preliminary magnetic wire exceeds 800°C, it was confirmed that the final formed magnetic wire is formed closer to the particle shape than the wire shape.

22 and 23 are photographs of magnetic wires according to Examples 9 to 12 of the present invention.

22 and 23, SEM photographs of the magnetic wires according to Examples 9 to 12, respectively, are shown in FIGS. 22(a), 22(b), 23(a), and 23. (b) respectively. 22 and 23, in the case of the magnetic wires according to Examples 9 to 11, it was confirmed that they were formed in a wire form. However, in the case of the magnetic wire according to Example 12, coarsening of particles occurred, and it was confirmed that the particles were formed closer to the particle shape than the wire.

24 is a graph analyzing the components of each of the second preliminary magnetic wire, the third preliminary magnetic wire, and the magnetic wire sequentially formed during the manufacturing process of the magnetic wire according to Example 2 of the present invention.

Referring to (a) to (c) of FIG. 24, 2-Theta for each of the second preliminary magnetic wire, the third preliminary magnetic wire, and the magnetic wire formed during the process of manufacturing the magnetic wire according to Example 2 above The component was analyzed by measuring the intensity (arb.units) according to (deg.).

As shown in FIG. 24(a), it was confirmed that the second preliminary magnetic wire contains Fe ₂ O _3, that is, Fe oxide. In addition, as can be seen in FIG. 24(b), it was confirmed that Fe ₃ O ₃ contained reduced Fe in the case of the third preliminary magnetic wire. In addition, as can be seen in FIG. 24(c), it was confirmed that in the case of the magnetic wire, Fe ₁₆ N ₂ containing nitrogen (N) atoms bonded to Fe was included. However, in the case of the magnetic wire, it was confirmed that not only Fe ₁₆ N ₂ but also Fe was included.

25 and 26 are graphs showing a characteristic change according to the heat treatment temperature of the first preliminary magnetic wire during the manufacturing process of the magnetic wire according to the embodiment of the present invention.

25 and 26, a magnetic wire is manufactured according to a manufacturing process of a magnetic wire according to an embodiment of the present invention, but the heating temperature of the first preliminary magnetic wire is 0°C to 1000°C at a heating rate of 10°C/min. The magnetic wire thus formed was subjected to TG-DTA (Thermogravimetry-Differential Thermal Analysis) and the results are shown. The concentration of PVP in the source solution used in the manufacturing process is 3.4 wt%.

As can be seen in Figures 25 and 26, during the manufacture of the magnetic wire according to the manufacturing process of the magnetic wire according to the embodiment, the first preliminary magnetic wire by changing the heat treatment temperature to 0 ~ 1000 ℃ magnetic wire is formed Only 3 times, it was confirmed that a significant change in weight occurred. The first weight change occurs at 100°C, which is believed to occur as moisture in the first pre-magnetic wire evaporates. The second weight change occurs at a portion of 200°C to 250°C, which is judged to occur as organic matter and PVP in the first preliminary magnetic wire are removed. The third weight change occurs at 300°C to 400°C, which is thought to be caused by the removal of residual PVP in the first preliminary magnetic wire and decomposition of NO _{3 in} the third preliminary magnetic wire.

27 is a graph analyzing the components of the magnetic wires according to Examples 1 to 4 of the present invention.

Referring to FIG. 27, for each of the magnetic wires according to Examples 1 to 4, components were analyzed by measuring intensity (arb.units) according to 2-Theta (deg.). The results shown in FIG. 27 can be summarized through <Table 3> below.

division	Fe 16 N 2 (wt %)	Fe (wt %)
Example 1	26.6	73.4
Example 2	54.2	45.8
Example 3	39.8	60.2
Example 4	51.3	48.7

27 and <Table 3>, it was confirmed that the magnetic wires according to Examples 1 to 4 were composed of Fe ₁₆ N ₂ and Fe. In addition, it was confirmed that the magnetic wire according to the second embodiment, in which the first preliminary magnetic wire was heat-treated at a temperature of 700° C., had the highest Fe ₁₆ N ₂ content.

28 is a graph analyzing the components of the magnetic wires according to Examples 9 to 12 of the present invention.

Referring to FIG. 28, for each of the magnetic wires according to Examples 9 to 12, components were analyzed by measuring intensity (arb.units) according to 2-Theta (deg.). The results shown in FIG. 28 can be summarized through <Table 4> below.

division	Fe 16 N 2 (wt %)	Fe (wt %)
Example 9	66.5	33.5
Example 10	57.5	42.5
Example 11	58.7	41.3
Example 12	60.7	39.3

28 and <Table 4>, the magnetic wires according to Examples 9 to 12 were also confirmed to be composed of Fe ₁₆ N ₂ and Fe. Further, it was confirmed that the magnetic wire according to the ninth embodiment, in which the first preliminary magnetic wire was heat-treated at a temperature of 600° C., had the highest Fe ₁₆ N ₂ content.

27 and 28, when the first preliminary wire is heat-treated in an atmosphere (Examples 1 to 4), the average proportion of Fe ₁₆ N _{2 in} the magnetic wire is 42.97 wt%, but oxygen (O ₂ ) When heat-treated in an atmosphere (Examples 9 to 12), it was found that the average ratio of Fe ₁₆ N _{2 in} the magnetic wire was 60.85 wt%.

29 to 32 are graphs showing characteristics of the second preliminary magnetic wire formed during the manufacturing process of the magnetic wires according to Examples 1 to 4 of the present invention.

Referring to FIGS. 29 to 32, for each of the second preliminary magnetic wires formed during the manufacturing process of the magnetic wires according to Examples 1 to 4, the intensity (CPS) according to 2-Theta (deg.) is measured, and 2 The crystallite size of the preliminary magnetic wire was calculated. The grain size was calculated by using Scherrer's equation to broaden the peaks shown in each graph.

As can be seen from FIGS. 29 to 32, the second preliminary magnetic wires formed during the manufacturing process of the magnetic wires according to Examples 1 to 4 were 180 Å, 290 Å, 314 Å, and 329 직경 in diameter, respectively. .

33 is a graph analyzing components of magnetic wires according to Examples 2, 5, and 6 of the present invention.

33, 2-Theta (deg. for each of the magnetic wires according to Example 2 (reduction temperature 320°C), Example 5 (reduction temperature 305°C), and Example 6 (reduction temperature 290°C). ) Intensity (arb.units) according to the measured components were analyzed. As can be seen in FIG. 33, it was confirmed that the magnetic wire according to Example 6, in which the second preliminary magnetic wire was reduced at a temperature of 290° C., had the highest Fe ₁₆ N ₂ content of 88.7 wt%.

34 is a graph analyzing the components of the magnetic wires according to Examples 6, 7, and 8 of the present invention.

34, 2-Theta (deg. for each of the magnetic wires according to Example 6 (nitride temperature 160°C), Example 7 (nitride temperature 150°C), and Example 8 (nitride temperature 140°C). ) Intensity (arb.units) according to the measured components were analyzed. As can be seen in FIG. 34, it was confirmed that the magnetic wire according to Example 6, in which the third preliminary magnetic wire was nitrided at a temperature of 160° C., had the highest Fe ₁₆ N ₂ content of 86.2 wt%.

35 is a graph showing a configuration change according to a flow rate of ammonia gas in a manufacturing process of a magnetic wire according to an embodiment of the present invention.

Referring to FIG. 35, a magnetic wire is manufactured according to the manufacturing process of the magnetic wire according to Example 2, but the flow rate of ammonia gas provided in the heat treatment process of the third preliminary wire is 0.5 L/min, 1.0 L/min, And 1.5 L/min, and analyzed the components of the magnetic wire prepared according to each. As can be seen in FIG. 35, when ammonia gas was provided at flow rates of 0.5 L/min and 1.0 L/min, Fe ₁₆ N ₂ iron nitride was not formed in the magnetic wire, but when ammonia gas was provided at a flow rate of 1.5 L/min , It was confirmed that Fe ₁₆ N ₂ iron nitride was formed in the magnetic wire. As described above, nitrogen atoms decomposed from ammonia gas are formed of nitrogen molecules over time, and nitrogen molecules cannot be penetrated into the third preliminary magnetic wire, so that Fe ₁₆ N ₂ iron nitride cannot be formed. Is judged. That is, it can be seen that the penetration into the nitrogen atom is the third spare magnetic wire Fe ₁₆ N ₂ iron nitride is formed, 1.5 L / min flow rate at least ammonia gas has to be provided, the iron nitride Fe ₁₆ N ₂ that is easily formed.

36 is a graph showing magnetic properties of a magnetic wire according to Example 6 of the present invention.

Referring to FIG. 36, the magnetic properties of the magnetic wire according to Example 6 were measured by measuring the intensity (arb.units) according to Applied Filed(Oe). The magnetic properties measured through FIG. 36 are summarized in <Table 5> below.

division	Saturation magnetization (emu/g)	Residual magnetization (emu/g)	Square ratio (%)	Coercive Force (Oe)
Example 6	176.22	68.356	38.792	1215.5

36 and <Table 5>, it was confirmed that the magnetic wire according to Example 6 exhibited a high saturation magnetization value of 176 emu/g or higher and a high coercive force of 1215 Oe or higher.

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.

The iron nitride magnetic nanowire according to an embodiment of the present invention can be used in various industrial fields such as permanent magnets, electric motors, sensors, and automobiles.

Claims (13)

1. Electrospinning a source solution containing Fe to form a first preliminary magnetic wire;

   Heat treating the first preliminary magnetic wire at a first temperature to form a second preliminary magnetic wire comprising Fe oxide;

   Heat-treating the second preliminary magnetic wire at a second temperature to form a third preliminary magnetic wire in which the Fe oxide is reduced; And

   Comprising the step of heat-treating the third preliminary magnetic wire in a source gas atmosphere containing nitrogen and a third temperature, to form a magnetic wire in which nitrogen is penetrated into the third preliminary magnetic wire,

   And controlling the saturation magnetization value of the magnetic wire by controlling at least one of the first to third temperatures.
2. According to claim 1,

   The first temperature is a method of manufacturing a magnetic wire comprising more than 600 ℃ less than 800 ℃.
3. According to claim 1,

   In the forming of the magnetic wire, a nitrogen atom (atom) decomposed from the source gas is penetrated into the magnetic wire,

   The infiltrated nitrogen atom is a method of manufacturing a magnetic wire, which includes bonding with Fe included in the magnetic wire.
4. According to claim 1,

   And controlling the saturation magnetization value by controlling the flow rate of the source gas provided in the forming of the magnetic wire.
5. According to claim 4,

   The source gas, the magnetic wire manufacturing method comprising providing at a flow rate of 1.5 L / min or more.
6. According to claim 1,

   The second preliminary magnetic wire forming step, the magnetic wire manufacturing method comprising performing in any one of the atmosphere (air) atmosphere or oxygen (O ₂ ) atmosphere.
7. According to claim 1,

   The second temperature and the third temperature is a magnetic wire manufacturing method comprising a lower than the first temperature.
8. According to claim 1,

   The source gas, a method of manufacturing a magnetic wire containing ammonia (NH ₃ ).
9. According to claim 1,

   A method of manufacturing a magnetic wire comprising increasing the grain size of the magnetic wire as the first temperature increases.
10. According to claim 1,

    The second preliminary magnetic wire includes Fe ₂ O ₃ ,

    The third preliminary magnetic wire includes α-Fe,

    The magnetic wire is a method of manufacturing a magnetic wire comprising Fe ₁₆ N ₂ .
11. Iron (Fe), and iron nitride (Fe _x N _y ),

    Magnetic wire comprising a content of the iron nitride is higher than the content of the iron. (x,y>0)
12. The method of claim 11,

    The iron nitride (Fe _x N _y ) is a magnetic wire comprising more than 88.7wt%.
13. The method of claim 11,

    Magnetic wire comprising x is 16 and y is 2.

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