Fe-based soft magnetic alloy, method for manufacturing the same, and magnetic component including the same

Abstract

The present invention provides an iron-based soft magnetic alloy. The iron-based soft magnetic alloy according to an embodiment of the present invention is represented by the empirical formula Fe a B b C c Cu d Nb e In the above empirical formula, a, b, c, d, and e are the atomic percentages (at%, atomic percent) of the corresponding elements, 78.0 ≤ a ≤ 84.5, and 15.5 ≤ b + c + d + e ≤ 22.0. Accordingly, the iron-based soft magnetic alloy has high saturation magnetic flux density and high magnetic permeability characteristics, can be used as small and lightweight components, has low coercive force and low magnetic loss characteristics, and thus is very easy to be used as high-performance / high-efficiency components. Moreover, when uniform and small-grained crystals are achieved after heat treatment, the influence of heat treatment conditions can be minimized, and process conditions are easy to design, so it is very suitable for mass production. Therefore, it can be widely used as magnetic components for electrical and electronic devices such as high-power lasers, high-frequency power supplies, high-speed pulse generators, switch-mode power supplies (SMPS), high-frequency filters, low-loss high-frequency transformers, high-speed switches, wireless power transmission, and electromagnetic wave shielding.

Description

Technical Field

[0001] The present invention relates to an iron-based soft magnetic alloy, a method for manufacturing the same, and a magnetic component using the same. Background Art

[0002] Soft magnetic materials are materials used for magnetic cores of various transformers, chokes, various sensors, saturable reactors, magnetic switches, etc., and are widely used in various electrical and electronic devices such as distribution transformers, laser power supplies, or accelerators for supplying or converting electric power. In the above-mentioned electrical and electronic fields, the market demand for soft magnetic materials is for miniaturization, light weight, high performance / high efficiency, and low product cost. In order to meet the above-mentioned market demands, active research is being conducted on soft magnetic materials having a high saturation magnetic flux density and low magnetic loss.

[0003] In addition, in recent years, in addition to the saturation magnetic flux density and magnetic loss, the demand for soft magnetic materials having excellent magnetic permeability has also been increasing. However, currently known iron-based soft magnetic materials are difficult to simultaneously satisfy the characteristics of high saturation magnetic flux density, low coercive force, low magnetic loss, and high magnetic permeability. Moreover, when applied to components for various uses, but when applied, in the case of changing the structure due to the shape, size, or inherent physical properties of the magnetic material, for example, when performing thin sheet processing to compensate for magnetic loss, etc., other physical properties may change significantly, making it difficult for a magnetic material with a specific composition to be commonly used in magnetic components realized by various uses, various forms, and sizes.

[0004] Therefore, there is an urgent need to develop a soft magnetic material having a high saturation magnetic flux density and magnetic permeability, minimizing magnetic loss and coercive force, and being commonly applicable to various magnetic components. Summary of the Invention

[0005] Technical Problem

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide an iron-based soft magnetic alloy and a method for manufacturing the same having the following characteristics: having high saturation magnetic flux density, maximum magnetic flux density, and high magnetic permeability characteristics, and thus can be used as a miniaturized and lightweight component, and having low coercive force and low magnetic loss characteristics, and thus is very easily used as a high-performance / high-efficiency component.

[0007] Furthermore, another object of the present invention is to provide an iron-based soft magnetic alloy and a method for manufacturing the same having the following characteristics: in the case of a component in the form of a magnetic core or a strip-shaped sheet in the form of a thin sheet processed from an iron-based soft magnetic alloy, having excellent saturation magnetic flux density and magnetic permeability characteristics and having low magnetic permeability loss, and thus can be used for various purposes.

[0008] Moreover, another object of the present invention is to provide an iron-based soft magnetic alloy that can minimize the influence of heat treatment conditions when uniform grain size crystals are achieved after heat treatment.

[0009] Furthermore, another object of the present invention is to provide a method for manufacturing an iron-based soft magnetic alloy as follows: Even if the iron-based soft magnetic alloy is repeatedly produced dozens or hundreds of times under the same conditions, magnetic physical properties between uniform soft magnetic alloys can be achieved, thereby expressing reproducibility very suitable for mass production.

[0010] Meanwhile, another object of the present invention is to provide magnetic components for various electrical and electronic devices such as electromagnetic field shielding, energy supply and conversion functions, etc., using the iron-based soft magnetic alloy of the present invention.

[0011] Technical solution

[0012] In order to achieve the above object, the present invention provides an iron-based soft magnetic starting alloy, which is represented by the empirical formula Fe a B b C c Cu d Nb e However, in the above empirical formula, a, b, c, d, and e are atomic percentages (at%, atomic percent) of the corresponding elements, and 78.0 ≤ a ≤ 84.5, 15.5 ≤ b + c + d + e ≤ 22.0.

[0013] According to an embodiment of the present invention, the structure of the above starting alloy may be an amorphous phase.

[0014] And, in the above empirical formula, a, b, c, d, and e may be 78.0 ≤ a ≤ 84.5, 12.5 ≤ b ≤ 17.0, 0.5 ≤ c ≤ 2, 0.5 ≤ d ≤ 1.2, and 0.8 ≤ e ≤ 3.0, respectively.

[0015] And, in the above empirical formula, a and b may be 79.0 ≤ a ≤ 82.0, 14.0 ≤ b ≤ 17.0.

[0016] And, in the above empirical formula, the value of the following Mathematical formula 1 for a, b, and e may be 4.7 to 6.0.

[0017] Mathematical formula 1:

[0018] Moreover, the present invention provides an iron-based soft magnetic alloy, which is manufactured by heat-treating a starting alloy represented by the empirical formula Fe a B b C c Cu d Nb e However, in the above empirical formula, a, b, c, d, and e are atomic percentages of the corresponding elements, and 78.0 ≤ a ≤ 84.5, 15.5 ≤ b + c + d + e ≤ 22.0.

[0019] According to an embodiment of the present invention, the present invention may include grains organized as amorphous or having an average grain size of 60 nm or less in an amorphous matrix phase.

[0020] Moreover, it may include 50 volume % or more of the above grains in the amorphous matrix phase, and more preferably, it may include 50 volume % to 70 volume % of the above grains. And the average grain size is 35 nm or less, preferably 25 nm or less.

[0021] Moreover, under a magnetic field of 800 A / m and 50 Hz, the saturation magnetic flux density is 1.5 T or more, the coercive force is 10.0 A / m or less, and under the conditions of 1 T and 50 Hz, the core loss can be 150 mW / kg or less.

[0022] Moreover, the present invention may be in the form of a strip having a specified thickness and width or a magnetic core having a specified outer diameter and inner diameter formed by winding the above tape multiple times.

[0023] Moreover, under the condition of 100 kHz, the magnetic permeability of the magnetic core formed of the above iron-based soft magnetic alloy is 3000 or more, and the real part of the complex magnetic permeability of the magnetic sheet can be 1000 or more.

[0024] Moreover, the present invention may not include coarse grains having a grain size greater than 80 nm in the grains distributed from the surface to a depth of 5 μm.

[0025] Moreover, the grains having a grain size within ±20% of the average grain size in the grains distributed from the surface to a depth of 5 μm can be 50% or more of the total grains.

[0026] Moreover, the present invention provides a method for manufacturing an iron-based soft magnetic alloy, which includes: manufacturing an iron-based initial alloy represented by the empirical formula Fe a B b C c Cu d Nb e (where a, b, c, d, and e are the atomic percentages of the respective elements, 78.0 ≤ a ≤ 84.5, 15.5 ≤ b + c + d + e ≤ 22.0); and a step of heat-treating the above iron-based initial alloy.

[0027] According to an embodiment of the present invention, the above heat treatment may include: a primary heat treatment performed at a first heat treatment temperature higher than the crystallization start temperature Tx1 of the above iron-based initial alloy; and a secondary heat treatment performed at a second heat treatment temperature lower than the first heat treatment temperature after performing the above primary heat treatment.

[0028] Moreover, the above-mentioned first heat treatment temperature may be greater than Tx1 °C and equal to or less than (Tx1 + 60) °C, and the above-mentioned second heat treatment temperature may be (Tx1 - 55) °C to (Tx1 + 20) °C.

[0029] Moreover, the above-mentioned primary heat treatment can be performed for 2 minutes to 30 minutes.

[0030] Moreover, the above-mentioned secondary heat treatment can be performed for 5 minutes to 70 minutes.

[0031] Moreover, the heating rate up to the above-mentioned first heat treatment temperature can be 100 °C / minute or less.

[0032] Moreover, the cooling rate from the above-mentioned first heat treatment temperature to the second heat treatment temperature can be 100 °C / minute or less.

[0033] Moreover, the iron-based soft magnetic alloy after the secondary heat treatment may contain nano-crystals with an average grain size of 60 nm or less.

[0034] Moreover, the present invention provides an electromagnetic wave shielding material containing the iron-based soft magnetic alloy of the present invention.

[0035] According to an embodiment of the present invention, the above-mentioned iron-based soft magnetic alloy is formed by laminating strip-shaped sheets broken into multiple pieces into one or more layers.

[0036] Moreover, the present invention provides a coil component, which includes: the iron-based soft magnetic alloy of the present invention; and a coil wound around the above-mentioned iron-based soft magnetic alloy.

[0037] Hereinafter, the terms used in the present invention will be described.

[0038] Among the terms used in the present invention, "initial alloy" refers to an alloy in a state where no separate treatment process such as heat treatment is performed for the purpose of changing the characteristics of the manufactured alloy.

[0039] Moreover, among the terms used in the present invention, "high frequency" refers to a frequency band of several tens of kHz to several tens of MHz such as 50 kHz to 10 MHz.

[0040] Effects of the Invention

[0041] According to the present invention, the iron-based soft magnetic alloy has high saturation magnetic flux density and high magnetic permeability characteristics, can be used as small and lightweight components, has low coercivity and low magnetic loss characteristics, and is very easy to be used as high-performance / high-efficiency components. Moreover, when uniform and small-grained crystals are achieved after heat treatment, the influence of heat treatment conditions can be minimized. Thus, it is easy to design process conditions, and it is very suitable for mass production. Therefore, it can be widely used as magnetic components for electrical and electronic devices such as high-output lasers, high-frequency power supplies, high-speed pulse generators, switch-mode power supplies, high-frequency filters, low-loss high-frequency transformers, high-speed switches, wireless power transmission, and electromagnetic wave shielding. Description of the Drawings

[0042] Figure 1 It is a graph of temperature conditions according to time when performing heat treatment included in the manufacturing method of an embodiment of the present invention.

[0043] Figure 2 It is an X-ray diffraction (XRD) pattern before heat treatment of the iron-based soft magnetic alloy of Example 1 and Example 2.

[0044] Figure 3 and Figure 4 It is an X-ray diffraction pattern and a transmission electron microscope (TEM) image of the iron-based soft magnetic alloy of an embodiment of the present invention.

[0045] Figure 5 and Figure 6 It is an X-ray diffraction pattern and a transmission electron microscope image of the iron-based soft magnetic alloy of an embodiment of the present invention.

[0046] Figure 7 is Figure 3 and Figure 4 VSM graph of the iron-based soft magnetic alloy.

[0047] Figure 8 is Figure 5 and Figure 6 VSM graph of the iron-based soft magnetic alloy.

[0048] Figure 9 It is a photo of the device for thinning the strip of the iron-based soft magnetic alloy of an embodiment of the present invention.

[0049] Figure 10 and Figure 11 It is a transmission electron microscope image of the iron-based soft magnetic alloy of an embodiment of the present invention.

[0050] Figure 12 It is a photo of the device for measuring the magnetic permeability of the iron-based soft magnetic alloy of an embodiment of the present invention. Detailed Description of the Invention

[0051] Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement the present invention. The present invention can be implemented in various different embodiments and is not limited to the embodiments described herein.

[0052] The iron-based soft magnetic starting alloy of the present invention is an alloy represented by the empirical formula Fe a B b C c Cu d Nb e In the above empirical formula, a, b, c, d, and e satisfy 78.0 ≤ a ≤ 84.5 and 15.5 ≤ b + c + d + e ≤ 22.0. In this case, the above a, b, c, d, and e refer to the atomic percentages of the corresponding elements.

[0053] First, the above Fe is the main element of the alloy expressing magnetism. In order to improve the saturation magnetic flux density and permeability together, the alloy contains Fe at 78.0 atomic percentage or more, preferably contains Fe at 78.5 atomic percentage or more, more preferably contains Fe at 79 atomic percentage or more, and even more preferably contains Fe at 79.5 atomic percentage or more. If Fe is less than 78.0 atomic percentage, it may not be possible to achieve the desired level of saturation magnetic flux density. And, it contains Fe at 84.5 atomic percentage or less, preferably contains Fe at 83 atomic percentage or less, more preferably contains Fe at 82 atomic percentage or less. If the alloy contains Fe greater than 84.5 atomic percentage, the saturation magnetic flux density will increase, but it may be difficult to express the desired level of permeability characteristics. In particular, when thin-film processing is performed, the real part of the permeability under high-frequency conditions may rapidly decrease. And, since the content of the remaining elements relatively decreases as the content of Fe increases, when performing the liquid quenching process for manufacturing the starting alloy, it may be difficult to make the crystal phase of the starting alloy into an amorphous phase, and the crystals generated in the starting alloy hinder uniform crystal growth in the heat treatment process for property change. As the size of the generated crystals becomes too large, the coercive force increases and the magnetic loss increases.

[0054] Thereafter, in the above empirical formula, B and C are elements with the ability to form amorphous phases, and the initial alloy can be manufactured in an amorphous phase by these elements. Moreover, the C element combines with the B element, and thus, compared with the case of only containing the B element, it has the following advantages: it is easy to control the grain size of the generated α-Fe crystals within the desired level and improve the thermal stability of the initial alloy. When heat treatment is performed, it is beneficial to obtain uniform α-Fe crystals. The total of the B element and the C element in the alloy can be 13.5 atomic percent to 19.0 atomic percent, and more preferably 15 atomic percent to 19 atomic percent. If the total of the B element and the C element in the alloy is less than 13.5 atomic percent, it may be difficult to manufacture the manufactured initial alloy into an amorphous phase, and it is difficult for the crystals in the initial alloy to uniformly grow multiple crystals generated during heat treatment for magnetic property change. Multiple crystals with a coarse particle size may be included, and thus, magnetic loss may increase. Moreover, in the case of containing more than 19.0 atomic percent, the content of other components after heat treatment, that is, Cu and / or Nb or the content of Fe, can be reduced. In the case where the content of Cu and / or Nb is reduced, it is difficult to grow the grains into a uniform particle size after heat treatment, or it is difficult to achieve the desired level of magnetic permeability. Moreover, in the case where the content of Fe is reduced, it may be difficult to exhibit the desired level of saturation magnetic flux density, magnetic permeability, etc.

[0055] As an example, the alloy may contain 12.5 atomic percent to 17 atomic percent of the above B element, and the alloy may contain 0.5 atomic percent to 2 atomic percent of the C element. Thus, when heat treatment is performed, it is easy to control the growth of the grains in the alloy and it is beneficial to exhibit the desired magnetic properties. Moreover, as another example, the alloy may contain 13 atomic percent to 17 atomic percent, 14 atomic percent to 17 atomic percent, or 15 atomic percent to 17 atomic percent of the above B element. In this case, the alloy may contain 0.5 atomic percent to 2 atomic percent of the C element. Thus, it is easy to control the particle size of the grains generated by heat treatment, and even in mass production, the reproducibility can be improved, and it is more beneficial to achieve a further increased magnetic permeability, a further reduced core loss, etc. At the same time, the iron-based soft magnetic alloy is beneficial to achieve excellent magnetic properties in various forms, for example, in magnetic cores, strip sheets, strip sheets processed into thin sheets, etc. In particular, it is beneficial to achieve excellent magnetic permeability characteristics at high frequencies.

[0056] Thereafter, in the above empirical formula, Cu is an element that serves as a nucleation site capable of generating α-Fe crystals in the initial alloy, enabling the initial alloy of the amorphous phase to be easily transformed into a nanocrystalline alloy. The above Cu element makes the crystalline phase of the initial alloy amorphous, and the crystals formed after heat treatment become nanocrystals. In order to significantly exhibit the desired physical properties, it can be included in the alloy at 0.5 atomic percentage to 1.2 atomic percentage, and more preferably, it can be included in the alloy at 0.7 atomic percentage to 1.2 atomic percentage. If the above Cu element contained in the alloy is less than 0.5 atomic percentage, the specific resistance of the manufactured alloy is greatly reduced, and the magnetic loss caused by eddy current can be increased. The nanocrystals of α-Fe are not generated at the desired level in the heat-treated alloy. In the case of crystal formation, it is difficult to control the particle size of the formed crystals. Moreover, if the alloy contains more than 1.2 atomic percentage of Cu element, the crystalline phase of the manufactured initial alloy can be crystalline. The crystals already formed in the initial alloy can make the grain size of the crystals formed during heat treatment uneven, and crystals growing larger than the desired size can be included in the alloy. Thus, it may not be possible to exhibit magnetic properties such as increased magnetic loss at the desired level. Also, as the contents of the above Fe, B, C elements and the Nb content described later relatively decrease, the effects caused by the corresponding elements can be reduced.

[0057] Thereafter, in the above empirical formula, Nb is an element that, while increasing the uniformity of the grain size in the alloy after heat treatment, reduces magnetostriction and magnetic anisotropy, thereby improving soft magnetic properties and contributing to the improvement of magnetic properties with respect to temperature changes. The above Nb can be included in the alloy at 0.8 atomic percentage to 3.0 atomic percentage. If the content of Nb is less than 0.8 atomic percentage, the saturation magnetic flux density can be slightly increased, but when heat treatment is performed, the reduction in the nanocrystal grain size is negligible, making it difficult to control the particle size. Therefore, it is difficult to achieve excellent properties such as core loss and magnetic permeability. Moreover, if the content of Nb is greater than 3.0 atomic percentage, there is a concern about an increase in manufacturing cost, the saturation magnetic flux density decreases, and the coercive force can be increased, making it difficult to achieve an amorphous state in the initial alloy. Also, as it is difficult to achieve an amorphous state in the initial alloy, it is difficult to control the particle size through heat treatment. Therefore, when mass-producing, there is a concern about a reduction in reproducibility and a concern about the inclusion of coarse grains in the alloy after heat treatment. Also, after forming a strip sheet and / or manufacturing it into a strip sheet with the corresponding composition, when performing thin sheet processing, it may be difficult to achieve the desired levels such as a significant reduction in the real part of the magnetic permeability and / or a slight reduction in the imaginary part.

[0058] In addition, in the composition of the iron-based soft magnetic alloy of the present invention, the Si element contained in the usual iron-based soft magnetic alloy is not included. The above Si element is well-known for reducing magnetostriction while improving the amorphous formation ability of the iron-based alloy. However, when Si is present, there is a problem that it is difficult to make the crystalline phase of the initial alloy into an amorphous phase. Also, when Si is included in the alloy, there is a problem that the content of metalloids such as B, C, Cu, and Nb other than Fe needs to be reduced or the content of Fe needs to be reduced. Reducing the content of Fe makes it difficult to achieve an iron-based alloy with a high saturation magnetic flux density. At the same time, when mass-producing, there is a concern that the reproducibility of the desired physical properties cannot be guaranteed.

[0059] Moreover, the present invention does not include the P element as an element constituting the alloy. The P element is well-known as an element that helps to achieve the microstructure. For the expression of this function, the content in the alloy needs to be 3 atomic percent or more. Thus, compared with Nb, the effect of achieving the microstructure is not good, and there is a problem of relatively reducing the content of other elements. Also, because the melting point of the P element is low, it is not easy to manufacture the alloy, and when manufacturing a strip, there is a problem of volatilization. Due to these factors, the P element makes it difficult for the initial alloy to be amorphous, difficult to control the crystal grain size by heat treatment of the initial alloy, and has a problem of being difficult to achieve a high magnetic permeability as it shows a low magnetic permeability characteristic in the high-frequency region. In particular, in order to reduce the magnetic loss caused by eddy currents, when performing a sheet process after heat treatment, compared with the iron-based alloy of the present invention that does not contain P, as the pulverization is excessive, the magnetic permeability is greatly reduced, and it is difficult to control the magnetic permeability.

[0060] As described above, the elements that are well-known for achieving iron-based soft magnetic alloys but are not used in the present invention instead have the problem of being difficult to express the magnetic properties to be achieved by the present invention. Therefore, in order to express certain functions, multiple elements can be used. However, if the element combination of the alloy of the present invention and the content range of these elements are not satisfied, it is difficult to simultaneously achieve all the physical properties desired by the present invention.

[0061] Therefore, preferably, in the above empirical formula, a, b, c, d, and e can be 78.0 ≤ a ≤ 84.5, 12.5 ≤ b ≤ 17.0, 0.5 ≤ c ≤ 2, 0.5 ≤ d ≤ 1.2, and 0.8 ≤ e ≤ 3.0, respectively. And, more preferably, a, b, c, d, and e can be 78.0 ≤ a ≤ 83.0, 13.0 ≤ b ≤ 17.0, 0.5 ≤ c ≤ 2, 0.5 ≤ d ≤ 1.2, and 0.8 ≤ e ≤ 3.0, respectively. Even more preferably, a, b, c, d, and e can be 79.0 ≤ a ≤ 82.0, 14.0 ≤ b ≤ 17.0, 0.5 ≤ c ≤ 2, 0.5 ≤ d ≤ 1.2, and 0.8 ≤ e ≤ 3.0, respectively. Further preferably, a, b, c, d, and e can be 79.5 ≤ a ≤ 82.0, 15.0 ≤ b ≤ 17.0, 0.5 ≤ c ≤ 2, 0.5 ≤ d ≤ 1.2, and 0.8 ≤ e ≤ 1.5, respectively. Thus, the manufacturing cost can be reduced. At the same time, the iron-based soft magnetic alloy can have excellent magnetic permeability in various shapes such as iron cores, strip sheets, and strip sheets processed from thin sheets, and has less magnetic loss. And it has the advantages of being easy to mass-produce through the primary heat treatment / secondary heat treatment processes described later and achieving further improved magnetic properties. At the same time, the iron-based soft magnetic alloy is beneficial to achieving excellent magnetic properties in various forms such as magnetic cores, strip sheets, and strip sheets processed from thin sheets. In particular, it is beneficial to achieving excellent magnetic permeability characteristics at high frequencies.

[0062] In addition, according to another embodiment of the present invention, in order to achieve excellent magnetic permeability, saturation magnetic flux density characteristics, and reduction of low magnetic losses such as core loss and coercive force, in the above empirical formula, a, b, c, d, and e can be 79.5 ≤ a ≤ 82, 18 ≤ b + c + d + e ≤ 20.5.

[0063] And, in the above empirical formula, the total content of Fe and Nb can be 78.8 atomic percentage to 85.5 atomic percentage, more preferably 79.8 atomic percentage to 84.0 atomic percentage, and even more preferably 81.0 atomic percentage to 83.0 atomic percentage. Thus, high magnetic permeability can be achieved at high saturation magnetic flux density and high frequencies, which is beneficial to controlling the crystal phases in the initial alloy and the alloy after heat treatment, and it is easy to achieve grains with uniform particle sizes. If the total content of Fe and Nb is less than 78.8 atomic percentage or greater than 86 atomic percentage, the magnetic permeability at high frequencies such as 100 kHz or 128 kHz will be significantly reduced and / or the saturation magnetic flux density will be significantly reduced. And it is difficult to control the grains, or coarse grains will be generated or the grains will become uneven.

[0064] Also, as an example, in the above empirical formula, the value of the following Mathematical Formula 1 for a, b, and e can be 4.7 to 6.0, more preferably 4.7 to 5.8, even more preferably 4.7 to 5.5, further preferably 4.7 to 5.3, and still further preferably 4.8 to 5.2. Thus, high magnetic permeability can be achieved at high saturation magnetic flux density and high frequency, which is beneficial for controlling the crystal phases in the initial alloy and the alloy after heat treatment, and it is easy to achieve grains with uniform particle sizes. If the value of the following Mathematical Formula 1 is less than 4.70, the saturation magnetic flux density is significantly low, or both the saturation magnetic flux density and the magnetic permeability at high frequency are significantly low. Also, when the value of the following Mathematical Formula 1 is greater than 5.60, the magnetic permeability at high frequency is significantly reduced, and / or the saturation magnetic flux density is significantly reduced. Moreover, it is difficult to control the grains, resulting in the generation of coarse grains or uneven grains, etc., and thus it may be difficult to achieve the object of the present invention.

[0065] Mathematical Formula 1:

[0066] The crystal phase of the iron-based soft magnetic initial alloy of an embodiment of the present invention having the above-described composition can actually be an amorphous phase. Thus, after heat treatment, the generation of coarse grains is prevented, and at the same time, it is beneficial for uniformly forming the particle sizes of the generated grains. Actually, the amorphous phase not only refers to a completely amorphous crystal phase, but also refers to a completely amorphous phase or a supermicrocrystal containing a part with a particle size less than 1 nm that is difficult to measure by the current technical level.

[0067] In addition, the iron-based soft magnetic alloy of the present invention has the empirical formula Fe a B b C c Cu d Nb e alloy, but may also contain inevitable impurities inadvertently included in the manufacturing process. As an example, the content of the above impurities can be 1 atomic percentage or less.

[0068] The heat-treated iron-based soft magnetic alloy of an embodiment of the present invention having the above-described composition can be manufactured by the manufacturing method described later, but is not limited thereto.

[0069] Specifically, it can be manufactured by including the following steps: a step of manufacturing an iron-based initial alloy represented by the empirical formula Fe a B b C c Cu d Nb e (where a, b, c, d, and e are the atomic percentages of the corresponding elements, 78.0 ≤ a ≤ 84.5, 15.5 ≤ b + c + d + e ≤ 22.0); and a step of heat-treating the above iron-based initial alloy.

[0070] First, the steps of manufacturing the initial alloy will be described. The iron-based initial alloy included in an embodiment of the present invention can be manufactured by the following process: After melting an iron-based alloy forming composition or an iron-based master alloy obtained by weighing and mixing base materials containing respective elements in a manner that satisfies the experimental formula of the iron-based alloy as described above, rapid solidification is performed. Depending on the specific method used during the above-mentioned rapid solidification, the shape of the manufactured iron-based initial alloy becomes different. The method used in the above rapid solidification can adopt a generally known method, and thus, the present invention does not particularly limit it. However, as a non-limiting example thereof, the above rapid solidification has a jet method (atomizing method) of manufacturing into a powder form by jetting a high-pressure gas (e.g., Ar, N2, He, etc.) and / or high-pressure water of the molten iron-based master alloy or iron-based alloy forming composition, a centrifugal separation method of manufacturing a powder form using a disk that rotates the molten metal rapidly, a melt spinning method of manufacturing a strip using a roll that rotates at high speed, etc. The shape of the iron-based soft magnetic initial alloy formed by this method can be a powder, a strip, or a core form in which the above strip is wound multiple times in a manner having a specified inner diameter and a specified outer diameter.

[0071] In addition, the shape of the above-mentioned iron-based starting alloy can also be a block. When the shape of the iron-based starting alloy is a block, the powder of the amorphous iron-based alloy formed by the method described above can be made into a bulk amorphous alloy by commonly known methods such as the coalescence method and the solidification method. As a non-limiting example of the above-mentioned coalescence method, methods such as shock consolidation, explosive forming, powder sintering, hot extrusion and hot rolling can be used. Among them, the shock consolidation method will be described. In the shock consolidation method, a shock wave is applied to the powder alloy polymer, so that the wave propagates along the grain boundaries, and the energy is absorbed at the grain boundaries. At this time, the absorbed energy forms a fine molten layer on the particle surface, so that a bulk amorphous alloy can be produced. The molten layer generated at this time needs to be cooled sufficiently quickly so that the amorphous state is maintained by heat transfer to the interior of the particles. By this method, a bulk amorphous alloy with a packing density of up to 99% of the original density of the amorphous alloy can be manufactured, and it can have the advantage of sufficient mechanical properties. Also, in the above-mentioned hot extrusion and hot rolling methods, by utilizing the fluidity of the amorphous alloy at high temperatures, the amorphous alloy powder is heated to a temperature around Tg and rolled. After roll forming, it can be quickly cooled to manufacture a bulk amorphous alloy with sufficient density and strength. In addition, the above-mentioned solidification methods include copper mold casting, high pressure die casting, arc melting, unidirectional melting, squeeze casting, strip casting, etc. Each method can adopt well-known methods and conditions, and therefore, the present invention does not particularly limit them. As an example, the above-mentioned copper mold casting method is as follows: a suction method of injecting molten metal into the interior of the mold by using the pressure difference between the inside and outside of the mold in a copper mold with high cooling capacity, or a method of injecting molten metal by applying a specified force externally using a pressurization method. By pressurization or suction, the molten metal injected into the copper mold at high speed is solidified by the metal, and thus, an amorphous iron-based starting alloy in a specified block shape can be manufactured.

[0072] After that, the iron-based soft magnetic starting alloy manufactured by the method described above can be heat-treated to have appropriate magnetic properties.

[0073] The above heat treatment is a step of transforming the atomic arrangement of the iron-based starting alloy from amorphous to crystalline, and nanocrystals containing α-Fe can be generated by the above heat treatment. However, depending on the temperature, heating rate, and / or treatment time during the heat treatment, etc., the size, shape, etc. of the generated crystals become different. Therefore, it is very important to adjust the heat treatment conditions for controlling the crystal grain size, content, and shape.

[0074] Specifically, preferably, the above heat treatment is performed at a temperature 60 °C or lower higher than the crystallization start temperature Tx1 of the iron-based starting alloy. As an example, it is performed at a heat treatment temperature of 430 °C to 530 °C. More preferably, it can be performed at a heat treatment temperature of 430 °C to 510 °C, and can be performed within 30 minutes. More preferably, it can be performed within 15 minutes. The heat treatment temperature can be adjusted according to the composition, and the time conditions can be appropriately adjusted according to the composition, heat treatment temperature, heating rate, etc. When the above heat treatment temperature is less than 430 °C, nanocrystals may not be generated or a small amount of nanocrystals may be generated. In this case, an iron-based soft magnetic alloy that does not exhibit the desired magnetic properties can be manufactured. And if the above heat treatment temperature is greater than 530 °C, the grain size of the crystals generated in the alloy can be coarsened, and the grain size distribution of the generated crystals becomes very wide. As a result, the uniformity of the grain size is reduced, and in addition to α-Fe, crystals of compounds between Fe and other metals are excessively generated, so that an iron-based alloy with uniform nanocrystalline α-Fe cannot be obtained. And due to the high heat treatment temperature, the heat treatment time can be relatively shortened, making it more difficult to control the generated grains. Furthermore, the realized iron-based soft magnetic alloy may not have the desired magnetic properties.

[0075] And according to an embodiment of the present invention, the heating rate up to the above heat treatment temperature also affects the control of the grain size of the generated nanocrystals. As an example, a maximum heating rate of 100 °C / minute from room temperature to the heat treatment temperature is beneficial for manufacturing an iron-based soft magnetic alloy having the desired magnetic properties.

[0076] However, even if the microstructure on the surface of the heat-treated alloy is realized to have a desired grain size distribution, it is difficult to control the grain size distribution of the grains distributed along the depth direction from the surface of the alloy. As a result, there is a problem that it is easy to realize a soft magnetic alloy with a large magnetic loss. And in the case where alloys with the same composition apply the same heat treatment method, there are cases where the grain size, volume fraction, distribution, and physical properties of the grains in the heat-treated alloy are uneven and it is difficult to mass-produce.

[0077] Accordingly, the above heat treatment of the present invention is carried out by performing a primary heat treatment and a secondary heat treatment at different temperatures. As a result, it is more suitable for manufacturing an iron-based soft magnetic alloy as follows: an iron-based soft magnetic alloy with uniform physical properties can be mass-produced, the volume fraction of nano-crystals is increased, the size and distribution are easier to control, the microstructure existing on the surface and along the depth direction from the surface in the alloy is more uniform, and the magnetic loss is significantly reduced. Furthermore, when the primary heat treatment and the secondary heat treatment are performed on the composition of the preferred iron-based soft magnetic alloy of the present invention, compared with the soft magnetic alloy subjected to the conventional heat treatment process, it has the advantages of an iron-based soft magnetic alloy that can achieve improved permeability and reduced core loss characteristics.

[0078] Refer to Figure 1 For illustration, the primary heat treatment is carried out at a first heat treatment temperature T1 higher than the crystallization start temperature Tx1 of the above iron-based initial alloy. After that, the secondary heat treatment is carried out at a second heat treatment temperature T2 lower than the first heat treatment temperature T1. If the second heat treatment temperature T2 is carried out at a temperature higher than the first heat treatment temperature T1, the permeability will be reduced instead, and there is a concern of reducing the maximum magnetic flux density, increasing the coercive force and the core loss. Also, for reproducibility, it is difficult to achieve an improved effect.

[0079] The above primary heat treatment can be carried out by maintaining a specified time at the first heat treatment temperature T1. Preferably, the heating rate up to the first heat treatment temperature T1 can be 100 °C / min or less, more preferably 10 °C / min to 100 °C / min. If the heating rate is less than 10 °C, when heating, a heat treatment effect is generated, and it is difficult to achieve magnetic properties and control the fine structure. In the case where the heating rate is greater than 100 °C, the equipment that meets the heating rate is limited, it is not easy to construct such equipment, and it is not suitable for mass production.

[0080] Based on the crystallization start temperature Tx1 in the DSC curve of the initial alloy manufactured in step 1, the first heat treatment temperature T1 is carried out at a temperature higher than it. Preferably, it can be carried out at a temperature greater than Tx1 and equal to or less than (Tx1 + 60) °C. If the primary heat treatment is carried out at a temperature of Tx1 °C or lower, the heat treatment time can be extended, and it is difficult to control the fine structure with the extended heat treatment time. Also, it may be difficult to achieve the desired level of permeability characteristics. And if the primary heat treatment is carried out at a temperature greater than (Tx1 + 60) °C, since the temperature is set too high, the heat treatment time needs to be shortened. Due to the short heat treatment time, it is not easy to obtain uniform characteristics and a uniform fine structure. Thus, when mass-producing, it is not preferred for reproducibility. Also, in the possible additional flaking process after heat treatment, the alloy may be excessively crushed and the permeability may be significantly reduced.

[0081] Moreover, the above primary heat treatment can be carried out at the first heat treatment temperature T1 as described above for 2 minutes to 30 minutes, more preferably, it can be carried out for 5 minutes to 25 minutes, and the specific time can be adjusted by the selected first temperature. If the holding time at the first temperature is less than 2 minutes, even if the first temperature is selected within a relatively high range, it is difficult to sufficiently generate crystallization at the desired level or to express the desired level of magnetic properties. When the first temperature is selected within a higher range, it is difficult to control crystal growth and physical property control. Therefore, there is a concern that the reproducibility will be significantly reduced. Also, if the holding time at the first temperature is greater than 30 minutes, there is a concern that the manufacturing time will be prolonged. Even if the selected first temperature is low, the desired level of magnetic properties cannot be expressed. When the selected first temperature is high, excessive heat treatment will cause the crystal phase to become coarser, resulting in a significant increase or excessive iron loss, making it impossible to be measured by the measuring equipment. The magnetic permeability will also be significantly reduced or become too small to be measured by the measuring equipment. After the above primary heat treatment, a secondary heat treatment is carried out at the second heat treatment temperature T2. The second heat treatment temperature T2 is carried out at a temperature lower than the crystallization start temperature Tx1 of the initial alloy. If the second heat treatment temperature is higher than the first heat treatment temperature, it is difficult to achieve the desired effect of the present invention. Preferably, the difference between the set first heat treatment temperature and the second heat treatment temperature can be 60 °C or less, more preferably 50 °C or less, even more preferably 15 °C to 50 °C, and further preferably 25 °C to 35 °C. If the temperature difference is greater than 60 °C, an appropriate grain size or distribution is not formed. Therefore, the improvement of the low maximum magnetic flux density value and magnetic permeability is negligible, and instead, the magnetic permeability is reduced. Also, there is a concern about achieving high coercivity and high core loss characteristics. At the same time, there is a concern that the reproducibility will be significantly reduced. Also, when the temperature difference of the second temperature is set to be less than 20 °C, there is a concern that the reproducibility will be reduced.

[0082] In this case, at the first heat treatment temperature T1 as described above, the cooling rate up to the second heat treatment temperature T2 can be 100 °C / minute or less, more preferably 10 °C / minute to 100 °C / minute. If the cooling rate is less than 10 °C / minute, it may be difficult to control the fine structure due to the heat treatment effect during the cooling process. Also, when the cooling rate is greater than 100 °C / minute, the effect increases negligibly, and there is a concern about the increase in manufacturing cost.

[0083] Preferably, the above-mentioned second heat treatment temperature T2 can be carried out at a temperature of (Tx1 - 55)°C to (Tx1 + 20)°C. If the secondary heat treatment is carried out at a temperature lower than (Tx1 - 55)°C, the heat treatment time will be prolonged, which is not conducive to mass production. Since the particles do not grow smoothly, it may be difficult to achieve properties such as low magnetic permeability and alloys with large magnetic losses. Also, if the secondary heat treatment is carried out at a temperature higher than (Tx1 + 20)°C, coarse particle growth will occur, thereby reducing magnetic properties such as increasing core loss or coercivity, and soft magnetic alloys with large physical property deviations can be manufactured, which is not preferred for reproducibility.

[0084] Moreover, the above-mentioned secondary heat treatment can be carried out at the above-mentioned second heat treatment temperature T2 for 5 minutes to 70 minutes. More preferably, it can be carried out for 10 minutes to 60 minutes, and the specific time can be adjusted by the selected second heat treatment temperature. Additionally, if the heat treatment is carried out at the second heat treatment temperature for a heat treatment time exceeding an appropriate level, a significant reduction in magnetic permeability and a significant increase in coercivity can be induced. Specifically, when the heat treatment time is less than 5 minutes, due to the short heat treatment, a uniform fine structure cannot be obtained, and it is difficult to achieve magnetic properties. Also, when the heat treatment time is greater than 70 minutes, abnormal grain growth may occur, thereby causing concerns about a reduction in physical properties such as a significant reduction in the real part or a significant increase in the imaginary part of the complex magnetic permeability.

[0085] In addition, after the secondary heat treatment at the second heat treatment temperature, the cooling rate to room temperature can be 30°C / minute to 300°C / minute, which is conducive to achieving the object of the present invention.

[0086] In the present invention, the following two-stage heat treatment process is carried out, that is, based on the crystallization start temperature Tx1 of the initial alloy, after one heat treatment is carried out at a temperature higher than it, a secondary heat treatment is carried out at a temperature lower than the one heat treatment. If one of the stages is omitted or the heat treatment order is changed to first carry out the heat treatment under the secondary heat treatment conditions and then carry out the heat treatment under the one heat treatment conditions, it is difficult to achieve the desired fine structure, and the magnetic loss cannot be reduced to the desired level.

[0087] In addition, in the above step 2, in addition to heating, pressure and / or a magnetic field can also be applied for execution. Through the additional treatment as described above, crystals with magnetic anisotropy in a specific direction can be generated. The degree of the pressure or magnetic field applied at this time can vary according to the desired physical property level, and the present invention does not particularly limit it, and it is also possible to carry it out under known conditions.

[0088] In the soft magnetic alloy manufactured by performing heat treatment on the iron-based starting alloy by the method as described above, it may contain an amorphous structure or grains with an average grain size of 60 nm or less in the amorphous matrix phase. Preferably, it may contain grains with an average grain size of 50 nm or less, more preferably, grains with an average grain size of 40 nm or less, still more preferably, grains with an average grain size of 35 nm or less, further preferably, grains with an average grain size of 25 nm or less, and even more preferably, grains with an average grain size of 20 nm or less. If the average grain size of the grains is greater than 60 nm, the desired magnetic properties such as an increase in coercivity and a decrease in magnetic permeability cannot be satisfied. However, when the proportion of grains with a grain size less than 15 nm in the grains is high, it is difficult to achieve a high magnetic permeability.

[0089] Moreover, when grains are included, it may contain 50 volume percent or more of grains. Preferably, it may contain 50 volume percent to 70 volume percent of grains, more preferably, 60 volume percent to 70 volume percent of grains. If it contains less than 50 volume percent of grains, the desired magnetic properties such as the desired level of saturation magnetic flux density cannot be expressed. And if it contains more than 70 volume percent of grains, in the generated crystals, in addition to α-Fe crystals, the formation of crystals of other compounds may increase, and the desired magnetic properties cannot be expressed. Also, when it contains more than 70 volume percent of grains, it is difficult to make the grain size of the grains uniform, and even when it is uniformly achieved, the improvement in physical properties is minimal.

[0090] Furthermore, by the heat treatment of the present invention as described above, coarse grains with a grain size greater than 80 nm in the grains distributed from the surface to a depth of 5 μm may not be included in the soft magnetic alloy. The average grain size is 60 nm or less, but if grains with a grain size greater than 80 nm are included, it may have a fine structure with non-uniform grain size, and thus, there is a concern about a decrease in magnetic permeability caused by an increase in magnetic anisotropy, and it may be difficult to reduce magnetic loss. Preferably, coarse grains with a grain size greater than 60 nm in the grains distributed from the surface to a depth of 5 μm may not be included in the soft magnetic alloy, and more preferably, coarse grains with a grain size greater than 40 nm may not be included.

[0091] Moreover, the average grain size of the above-described iron-based soft magnetic alloy is 60 nm or less. At the same time, the grain sizes can be very uniform. In particular, the grain sizes of the grains located on the surface can be uniform. Also, the grain sizes can be uniform from the surface of the alloy to the grains distributed along the depth direction. As a result, a very low coercive force and core loss are achieved, and thus a magnetic loss significantly lower than that of an iron-based soft magnetic alloy with the same composition as the existing one can be realized. Preferably, in the above-described iron-based soft magnetic alloy, the grains having a grain size within ±20% of the specified average grain size among the grains distributed from the surface to a depth of 5 μm can be 50% or more of the total grains, more preferably 65% or more, even more preferably 70% or more, and further preferably 80% or more. Thereby, it is possible to suitably exhibit a significantly low magnetic loss at a desired level. If the grains having a grain size exceeding ±20% of the specified average grain size are less than 50% of the total grains, a fine structure with non-uniform grain size distribution of the grains present in the soft magnetic alloy can be realized. As a result, it is difficult to reduce the magnetic loss to the desired level.

[0092] Moreover, preferably, the difference in average grain size between a group of first grains distributed from the surface to a depth of 2.5 μm and a group of second grains distributed from a depth of 2.5 μm from the surface of the above-described iron-based alloy to a depth of 5.0 μm can be 10 nm or less, more preferably 5 nm or less, and even more preferably 2 nm or less. As a result, as the grain size distribution of the grains distributed along the depth direction from the surface of the iron-based soft magnetic alloy is very uniform, it is possible to suitably exhibit a significantly low magnetic loss at a desired level.

[0093] The above-described iron-based soft magnetic alloy produced can be in the form of a strip having a specified thickness and width or a magnetic core having a specified outer diameter and inner diameter formed by winding the above-described strip multiple times. When the above-described iron-based soft magnetic alloy is a magnetic core, in a magnetic field of 800 A / m and 50 Hz, the saturation magnetic flux density can be 1.5 T or more, the coercive force can be 10.0 A / m or less, and in a magnetic field of 1 T and 50 Hz, the core loss can be 150 mW / kg or less. Also, the maximum magnetic flux density measured under the same conditions can be 1.45 T or more. In this case, the magnetic core can be formed by winding a strip having a thickness of about 20 μm and a width of 20 mm, and the outer diameter of the winding is 20 mm and the inner diameter is 10 mm.

[0094] Moreover, when the outer diameter is 20 mm and the inner diameter is 10 mm at a frequency of 100 kHz, the magnetic permeability of the above-described magnetic core can be 3000 or more, more preferably 3500 or more, 4800 or more, 5500 or more, 6000 or more, and more preferably 6500 or more.

[0095] Moreover, the iron-based soft magnetic alloy according to an embodiment of the present invention as described above can be realized as a magnetic component for electrical and electronic devices.

[0096] As an example, the above-mentioned iron-based soft magnetic alloy can be realized as an electromagnetic wave shielding material. In this case, the above-mentioned soft magnetic alloy can be in the form of a strip, and one or more strips can be laminated. The above-mentioned electromagnetic wave shielding material can also include a protective component covering the upper and lower parts of the strip laminated in a single layer or multiple layers. The above-mentioned protective component can use a well-known protective component used in the electromagnetic wave shielding material. Therefore, the present invention does not particularly limit it.

[0097] In addition, the iron-based soft magnetic alloy in the form of a strip provided in the electromagnetic wave shielding material can be provided in the electromagnetic wave shielding material in a form in which one or more layers of strips crushed into a plurality of blocks by flake treatment to improve the magnetic loss caused by eddy currents are laminated. However, as the strip is in a crushed state, the magnetic permeability can vary depending on the gap interval, size, shape, etc. between the plurality of crushed blocks. Therefore, preferably, it can be crushed into an appropriate size, appropriately spaced apart, and an appropriate shape considering this. In the case of crushing into too small a size, the magnetic permeability can be significantly reduced, and in the case of crushing into blocks of too large a size, the reduction in magnetic loss is negligible.

[0098] As described above, in the electromagnetic wave shielding material according to an embodiment of the present invention in which the strip is subjected to flake treatment, at a frequency of 100 kHz, the real part (μ') of the complex magnetic permeability can be 1000 or more, more preferably 1200 or more, even more preferably 1300 or more, and further preferably 1400 or more, and the imaginary part (μ") can be 200 or less. And, the above-mentioned iron-based soft magnetic alloy can be realized as a coil component. In this case, the soft magnetic alloy can be in the form of a magnetic core, and a coil can be wound around the outside of the above-mentioned magnetic core. The above-mentioned coil component can be applied to components such as lasers, transformers, inductors, motors, or generators.

[0099] Embodiments of the Invention

[0100] The present invention will be more specifically described by the following examples. However, the following examples are not limited to the scope of the present invention, and this should be interpreted as being helpful for understanding the present invention.

[0101] Example 1

[0102] Weigh the raw materials of Fe, B, C, Nb, and Cu to manufacture an Fe master alloy represented by the empirical formula Fe 80.3 B 16.8 C 1.0 Cu 0.9 Nb 1.0 and manufacture the Fe master alloy using the arc melting method. After that, after melting the manufactured Fe master alloy, it was rapidly cooled at a rate of 60 m / s by melt spinning in an Ar atmosphere at a speed of 10 6 K / sec to manufacture an iron-based soft magnetic starting alloy in the form of a strip with a thickness of about 20 μm and a width of about 20 mm.

[0103] After that, the manufactured tape-shaped iron-based soft magnetic starting alloy was wound to make the outer diameter 20 mm and the inner diameter 10 mm. Under normal temperature conditions, the starting alloy in the shape of a magnetic core or the tape-shaped starting alloy was heat-treated at a heating rate of 80 °C / minute and held at a temperature of 470 °C for 10 minutes, thereby manufacturing an iron-based soft magnetic alloy as shown in Table 1 below.

[0104] Examples 2 to 16

[0105] Manufactured by carrying out in the same manner as in Example 1, with the composition and / or heat treatment temperature changed as shown in Table 2 or Table 3 below, thereby manufacturing an iron-based soft magnetic alloy as shown in Table 2 or Table 3 below.

[0106] Comparative Examples 1 to 5

[0107] Manufactured by carrying out in the same manner as in Example 1, with the composition and / or heat treatment temperature changed as shown in Table 3 below, thereby manufacturing an iron-based soft magnetic alloy as shown in Table 3 below.

[0108] Experimental Example 1

[0109] The starting alloys and the heat-treated alloys manufactured in Examples 1 to 16 and Comparative Examples 1 to 5 were respectively evaluated for the following physical properties and are shown in Tables 1 to 3.

[0110] 1. Crystalline structure analysis

[0111] To confirm the crystalline phase of the manufactured starting alloy and heat-treated alloy and the average particle size of the generated crystals, the X-ray diffraction pattern and transmission electron microscope were analyzed. In this case, in Figure 2 The X-ray diffraction patterns of the iron-based soft magnetic alloys before heat treatment in Example 1 and Example 2 in the analysis results are shown. And, in Figure 3 and Figure 4 The X-ray diffraction pattern and transmission electron microscope image of Example 1 after heat treatment are respectively shown, and in Figure 5 and Figure 6 The X-ray diffraction pattern and transmission electron microscope image of Example 2 after heat treatment are respectively shown.

[0112] In this case, in the X-ray diffraction pattern, the volume fraction (volume percentage) of the crystals was calculated by the following relational expression 1.

[0113] Relational expression 1: Volume percentage = [crystalline region area / (crystalline region area + amorphous region area)] × 100 And the average particle size was derived by the Scherrer formula as shown in the following relational expression 2.

[0114] Relationship 2:

[0115] Wherein, D refers to the average particle size of the crystal, β refers to the half-width of the peak with the maximum intensity, and θ refers to the angle of the peak with the maximum intensity.

[0116] 2. Magnetic property evaluation

[0117] To calculate the coercive force and saturation magnetization value (Bs) or maximum magnetic flux density (Bm) for the sample 1 as the magnetic core, a vibrating sample magnetometer (VSM) was used and the evaluation was carried out under the conditions of 800 A / m and 50 Hz. Also, the Pcm was evaluated using the measuring device BH tracer (Iwaki Communication Co., Ltd., SY-8219) under the conditions of 1 T and 50 Hz. And after inserting a toroidal magnetic core into a plastic wire tube of the same size, it was wound 20 times with a copper wire coated with an insulating material, and then the magnetic permeability was measured using an LCR meter. In this case, the measurement was carried out under the conditions of a frequency of 100 kHz and 1 V.

[0118] Among them, in Figure 7 and Figure 8 the VSM curve graphs of the iron-based soft magnetic alloys of Example 1 and Example 2 are respectively shown.

[0119] And for the sample 2 sourced from the strip, the real part and the imaginary part of the magnetic permeability were measured at a frequency of 100 kHz using the special fixture (KEYSIGHT 42942A, 16454A) as Figure 12 shown.

[0120] In this case, the sample 2 was manufactured by the following method: after attaching protective films to the upper and lower surfaces of the strip, it was thinned 3 times using the thin film device as Figure 9 shown to be made into a toroidal shape with an outer diameter of 20 mm and an inner diameter of 10 mm.

[0121] Table 1

[0122]

[0123]

[0124]

[0125] Table 2

[0126]

[0127]

[0128]

[0129] Table 3

[0130]

[0131]

[0132]

[0133] As can be confirmed from Tables 1 to 3, compared with the iron-based soft magnetic alloy of the comparative example, the magnetic properties of the iron-based soft magnetic alloy of the example are excellent. When its shape is made into different magnetic cores and magnetically sliced sheets, excellent permeability characteristics can be known.

[0134] Examples 17 to 18

[0135] Manufactured by implementing in the same manner as Example 1, for the heat treatment of the initial alloy, heat treatment can be performed from room temperature at a heating rate of 80 °C / minute under the conditions shown in Table 4, thereby manufacturing an iron-based soft magnetic alloy.

[0136] Example 19

[0137] Manufactured by implementing in the same manner as Example 1. For the heat treatment of the initial alloy, after heating from room temperature to 460 °C at a heating rate of 80 °C / minute, heat treatment is performed for 10 minutes. Then, it is cooled to 445 °C at a cooling rate of 70 °C / minute, heat treatment is performed for 15 minutes at the corresponding temperature, and it is cooled to room temperature of 25 °C at a temperature cooling rate of 250 °C / minute to manufacture an iron-based soft magnetic alloy as shown in Table 4 below.

[0138] Examples 20 to 24

[0139] Manufactured in the same manner as Example 19, and the heat treatment for the initial alloy is changed to that shown in Table 4 or Table 5 below, thereby manufacturing an iron-based soft magnetic alloy.

[0140] Experimental Example 2

[0141] For the iron-based soft magnetic alloys of Examples 17 to 24, after manufacturing a total of 100 magnetic core test pieces 1 of different examples, the crystal structure analysis and magnetic properties of these test pieces were measured in the same manner as Experimental Example 1. At this time, in the case of magnetic properties, the average value of 100 test pieces was calculated, and in the case of average permeability, the standard deviation was calculated together and shown in Table 4 or Table 5.

[0142] And when analyzing the crystal structure, Figure 10 and Figure 11 Transmission electron microscope images of Example 20 and Example 22 measured are shown respectively.

[0143] Table 4

[0144]

[0145]

[0146] Table 5

[0147]

[0148]

[0149] As can be confirmed from Table 4 and Table 5, compared with Examples 17 and 18 in which heat treatment is performed in one stage, in the case of Examples 19 and 20 in which heat treatment is performed in two stages, the standard deviation of permeability of Examples 18 to 21 is small, and thus excellent reproducibility can be confirmed.

[0150] Moreover, in the case of performing two-stage heat treatment, it is known that the reproducibility of Example 24 with a second heat treatment temperature higher than the first heat treatment temperature is poor, and the permeability improvement effect is very small.

[0151] As described above, one embodiment of the present invention has been described. However, the idea of the present invention is not limited to the embodiments presented in this specification. Those of ordinary skill in the art who understand the idea of the present invention can easily propose different embodiments by adding, changing, deleting, adding, etc. of structural elements within the same scope of the idea, and this will also fall within the scope of the idea of the present invention.

Claims

1. A Fe-based soft magnetic alloy, characterized in that, Manufactured by heat-treating an initial alloy represented by the empirical formula Fe a B b C c Cu d Nb e and obtained by heat-treating an initial alloy represented by the empirical formula Fe wherein, in the above empirical formula, a, b, c, d, and e are atomic percentages of the corresponding elements, and satisfy 78.0 ≤ a ≤ 84.5, 15.5 ≤ b + c + d + e ≤ 22.0, 12.5 ≤ b ≤ 17.0, 0.5 ≤ c ≤ 2, 0.5 ≤ d ≤ 1.2, and 0.8 ≤ e ≤ 3.0, and in the said empirical formula, the value of mathematical formula 1 for a, b, and e is 4.7 to 5.

3. The mathematical formula 1 is wherein, the Fe-based soft magnetic alloy contains grains with an average grain size of 35 nm or less, and does not contain coarse grains with a grain size greater than 40 nm in the grains distributed from the surface to a depth of 5 μm.

2. The iron-based soft magnetic alloy according to claim 1, wherein In the above empirical formula, a and b are 79.0 ≤ a ≤ 82.0 and 14.0 ≤ b ≤ 17.0 respectively.

3. The iron-based soft magnetic alloy according to claim 1, wherein, Under a magnetic field of 800 A / m and 50 Hz, the saturation magnetic flux density is 1.5 T or more, the coercive force is 10.0 A / m or less, and under the conditions of 1 T and 50 Hz, the core loss is 150 mW / kg or less.

4. The iron-based soft magnetic alloy according to claim 1, characterized in that, The average grain size of the crystal is 35 nm or less and the volume fraction is 50% or more.

5. The iron-based soft magnetic alloy according to claim 1, wherein, The grains with a grain size within ±20% of the average grain size in the grains distributed from the surface to a depth of 5 μm are 50% or more of the total grains.

6. The iron-based soft magnetic alloy according to claim 1, wherein, Under the condition of 100 kHz, the magnetic permeability of the magnetic core formed by the above Fe-based soft magnetic alloy is 3000 or more, and the real part of the complex magnetic permeability of the sheet magnetic piece is 1000 or more.

7. A method for manufacturing an iron-based soft magnetic alloy, characterized in that, Including: Steps of manufacturing an iron-based starting alloy represented by the empirical formula Fe a B b C c Cu d Nb e ; and The step of heat-treating the above Fe-based initial alloy; wherein, in the above empirical formula, a, b, c, d, and e are atomic percentages of the corresponding elements, and satisfy 78.0 ≤ a ≤ 84.5, 15.5 ≤ b + c + d + e ≤ 22.0, 12.5 ≤ b ≤ 17.0, 0.5 ≤ c ≤ 2, 0.5 ≤ d ≤ 1.2, and 0.8 ≤ e ≤ 3.0, and in the said empirical formula, the value of mathematical formula 1 for a, b, and e is 4.7 to 5.

3. The mathematical formula 1 is wherein, the manufactured Fe-based soft magnetic alloy contains grains with an average grain size of 35 nm or less, and does not contain coarse grains with a grain size greater than 40 nm in the grains distributed from the surface to a depth of 5 μm.

8. The method for manufacturing an iron-based soft magnetic alloy according to claim 7, characterized in that, The above heat treatment includes: A primary heat treatment, performed at a first heat treatment temperature higher than the crystallization start temperature (Tx1) of the above Fe-based initial alloy; and A secondary heat treatment, performed at a second heat treatment temperature lower than the above first heat treatment temperature after the above primary heat treatment.

9. The method for manufacturing an iron-based soft magnetic alloy according to claim 8, characterized in that, The above first heat treatment temperature is greater than Tx1 °C and equal to or less than (Tx1 + 60) °C, and the above second heat treatment temperature is (Tx1 - 55) °C to (Tx1 + 20) °C.

10. The method for manufacturing an iron-based soft magnetic alloy according to claim 8, characterized in that, The above primary heat treatment is performed for 2 minutes to 30 minutes.

11. The method for manufacturing an iron-based soft magnetic alloy according to claim 8, characterized in that, The above secondary heat treatment is performed for 5 minutes to 70 minutes.

12. An electromagnetic wave shielding material, characterized in that, Including the Fe-based soft magnetic alloy according to any one of claims 1 to 6.

13. The electromagnetic wave shielding material according to claim 12, wherein The above Fe-based soft magnetic alloy is formed by laminating strip-shaped sheets broken into multiple pieces into one layer or multiple layers.

14. A coil component, characterized in that, Including: The Fe-based soft magnetic alloy according to any one of claims 1 to 6; and A coil wound around the above Fe-based soft magnetic alloy.

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