Magnetic assembly and magnetic particle

Abstract

The invention provides a magnetic assembly and a magnetic particle. The magnetic assembly includes a magnetic body, in which the magnetic body includes a plurality of magnetic particles including an Fe-based alloy, a first layer is formed on a surface of at least a portion of the plurality of magnetic particles, and a second layer is formed on a surface of the first layer, the first layer includes an Fe oxide component and has an average thickness of less than 5 nm, and the second layer includes an Si oxide component and has an average thickness of not less than 5 nm.

Description

[0001] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0131879 filed on October 4, 2023 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0002] The present disclosure relates to a magnetic component and magnetic particles. Background Art

[0003] As electronic devices such as digital televisions (TVs), mobile phones, and notebook computers are miniaturized and thinned, magnetic components applied to the electronic devices are also required to be miniaturized and thinned, and various types of magnetic components can be used to meet the requirements. An example of the magnetic component may be an inductor including a coil, and research and development on coil-type or film-type inductors are being actively conducted.

[0004] The main issue of miniaturization and thinning of magnetic components is to achieve equivalent characteristics to the past despite such miniaturization and thinning. In order to meet such requirements, the ratio of magnetic material in the core filled with magnetic material should be increased, but there may be limitations on increasing this ratio due to the strength of the magnetic body and changes in frequency characteristics due to insulation.

[0005] As an example of manufacturing a magnetic component, a method of making a magnetic body by stacking a sheet mixed with magnetic particles, resin, etc. on a coil and then pressing it can be used. Ferrite, metal, etc. can be used as such magnetic particles. When metal magnetic particles are used, it is advantageous to increase the content of the magnetic particles in terms of the magnetic permeability characteristics of the magnetic component, but in this case, the insulation of the magnetic body may be reduced, resulting in eddy current loss. In addition, when an insulating layer is coated on the surface of the metal magnetic particles, the proportion of the metal magnetic particles in the magnetic body may be reduced, which may be detrimental to achieving magnetic properties. Summary of the invention

[0006] An aspect of the present disclosure is to improve the magnetic permeability, saturation magnetic flux value, etc. of a magnetic component by forming a surface insulating layer of a magnetic particle thin so that the magnetic particle has excellent magnetic characteristics.

[0007] According to one aspect of the present disclosure, a magnetic component includes: a magnetic body, wherein the magnetic body includes a plurality of magnetic particles, the plurality of magnetic particles include an Fe-based alloy, a first layer is formed on the surface of at least a portion of the plurality of magnetic particles and a second layer is formed on the surface of the first layer, the first layer includes an Fe oxide component and has an average thickness of less than 5 nm, and the second layer includes an Si oxide component and has an average thickness greater than or equal to 5 nm.

[0008] In an embodiment, the first layer may include a Si composition of less than 1 wt %.

[0009] In an embodiment, the second layer may include a Si composition of 30 wt % to 70 wt %.

[0010] In an embodiment, the average thickness of the second layer may be less than 50 nm.

[0011] In an embodiment, the average thickness of the second layer may be 2 to 10 times the average thickness of the first layer.

[0012] In an embodiment, the average diameter of the plurality of magnetic particles may be 10 μm to 25 μm.

[0013] In an embodiment, a third layer may be formed on a surface of the second layer.

[0014] In an embodiment, the third layer may include at least one functional group of an alkyl group, a carbonyl group, and a urethane acrylate group.

[0015] In an embodiment, the magnetic body may include at least one of oleic acid, a derivative of oleic acid, and n-allyl neopentyl carbonate.

[0016] In an embodiment, the average thickness of the third layer may be less than 10 nm.

[0017] In an embodiment, the Fe-based alloy may include a Fe-Si-BC-based material.

[0018] In an embodiment, the Fe-based alloy may not include Cr, Mo, Nb, and P components.

[0019] In an embodiment, the Fe content in the Fe-based alloy may exceed 90 wt %.

[0020] In an embodiment, the Si content in the Fe-based alloy may be 0.1 wt % to 5 wt %.

[0021] In an embodiment, the magnetic body may further include additional magnetic particles having an average diameter smaller than an average diameter of the plurality of magnetic particles.

[0022] In an embodiment, the additional magnetic particles may include carbonyl iron particles.

[0023] According to another aspect of the present disclosure, there is provided a magnetic particle, comprising: a core comprising an Fe-based alloy; a first layer disposed on a surface of the core, the first layer comprising an Fe oxide component and having an average thickness of less than 5 nm; and a second layer disposed on a surface of the first layer, the second layer comprising an Si oxide component and the average thickness of the second layer is 2 to 10 times the average thickness of the first layer.

[0024] According to another aspect of the present disclosure, a magnetic component is provided, comprising a coil and a magnetic body comprising a magnetic core, the coil being wound around the magnetic core and encapsulated in the magnetic body, wherein at least a portion of the magnetic body comprises the magnetic particles as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other aspects, features and advantages of the present disclosure will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which: Figure 1 is a schematic perspective view showing a magnetic assembly according to an embodiment of the present disclosure.

[0026] Figure 2 yes Figure 1 A cross-sectional view of a region of a magnetic component.

[0027] Figure 3 yes Figure 1 A magnified view of a region of the magnetic body in the magnetic assembly.

[0028] Figure 4 It is shown how to reduce the thickness of the surface insulating layer in magnetic particles.

[0029] Figure 5 Magnetic particles employed in a magnetic component according to a modified example are shown.

[0030] Figure 6 An enlarged view of a region of a magnetic body of a magnetic assembly according to a modified example is shown.

[0031] Figure 7 is a schematic perspective view showing a magnetic assembly according to another embodiment of the present disclosure.

[0032] Figure 8 yes Figure 7 Schematic exploded perspective view of the magnetic assembly.

[0033] Fig. 9 yes Figure 7 A cross-sectional view of a region of a magnetic component. DETAILED DESCRIPTION

[0034] Hereinafter, embodiments of the present disclosure will be described with reference to specific embodiments and the accompanying drawings. However, embodiments of the present disclosure may be modified to have various other forms, and the scope of the present disclosure is not limited to the embodiments described below. In addition, embodiments of the present disclosure may be provided to more completely explain the present disclosure to those skilled in the art. Therefore, in order to describe more clearly, the shapes and sizes of the components in the accompanying drawings may be exaggerated, and the elements indicated by the same reference numerals in the accompanying drawings may be the same elements.

[0035] Various types of electronic components can be used in electronic devices, and in these electronic components, various types of coil components can be appropriately used for purposes such as noise removal. In other words, the coil components in electronic devices can be used as power inductors, high-frequency inductors, ordinary magnetic beads, high-frequency magnetic beads (for example, magnetic beads suitable for GHz bands), common mode filters, etc.

[0036] Figure 1 is a schematic perspective view showing a magnetic assembly according to an embodiment of the present disclosure. Figure 2 yes Figure 1 A cross-sectional view of a region of a magnetic component. Figure 3 yes Figure 1 A magnified view of a region of the magnetic body in the magnetic assembly.

[0037] Reference Figures 1 to 3 According to the present embodiment, the magnetic component 100 may include a magnetic body 101, the magnetic body 101 includes a plurality of magnetic particles 111, and, in this case, a first layer 112 may be formed on the surface of at least a portion of the plurality of magnetic particles 111 and a second layer 113 may be formed on the surface of the first layer 112. In terms of materials, the first layer 112 may include an Fe oxide component, and the average thickness t1 of the first layer 112 may be less than 5 nm. In addition, the second layer 113 may include an Si oxide component, and the average thickness t2 of the second layer 113 may be greater than or equal to 5 nm. By having such a coating structure, the volume fraction occupied by the Fe oxide layer on the magnetic particles 111 may be reduced, thereby minimizing the reduction in the magnetic permeability characteristics of the magnetic particles 111, and also improving the insulation characteristics of the magnetic particles 111. Hereinafter, the main components constituting the magnetic component 100 of the present embodiment are described. As an example, if the entirety of the magnetic particle 111 , the first layer 112 , and the second layer 113 (optionally, also including the third layer 114 described below) is regarded as one magnetic particle, the magnetic particle 111 may also be referred to as a core.

[0038] The magnetic body 101 may form the exterior of the magnetic assembly 100, and the coil 103 and the support member 102 supporting the coil 103 may be disposed inside the magnetic body 101. Figure 3As shown, the magnetic particles 111 may be dispersed inside the insulating material 110. The insulating material 110 may include a dispersant, an adhesive, etc., and may include a polymer component such as an epoxy resin, a polyimide, etc. The magnetic body 101 may be formed to have a hexahedral shape. The magnetic component 100 may have a thickness in a first direction D1, a length in a second direction D2, and a width in a third direction D3. As an example, the magnetic body 101 may be formed so that the magnetic component 100 in which the external electrodes 105 and 106 are formed according to the present embodiment has a length of 2.5 mm, a width of 2.0 mm, and a thickness of 1.0 mm, a length of 2.0 mm, a width of 1.2 mm, and a thickness of 0.65 mm, a length of 1.6 mm, a width of 0.8 mm, and a thickness of 0.8 mm, a length of 1.0 mm, a width of 0.5 mm, and a thickness of 0.5 mm, or a length of 0.8 mm, a width of 0.4 mm, and a thickness of 0.65 mm, but the present disclosure is not limited thereto. Since the above values ​​are merely design values ​​that do not reflect process errors and the like, the numerical range that can be identified as process errors should be considered to fall within the scope of the present disclosure.

[0039] The thickness of the magnetic assembly 100 in the first direction D1 may refer to: based on an optical microscope image or a scanning electron microscope (SEM) image of a cross section from the first direction D1 to the third direction D3 taken from the central portion of the magnetic assembly 100 in the second direction D2, the maximum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of the magnetic assembly 100 shown in the image and parallel to the first direction D1, the minimum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of the magnetic assembly 100 shown in the image and parallel to the first direction D1, or the arithmetic mean of at least three dimensions of a plurality of line segments connecting two outermost boundary lines of the magnetic assembly 100 shown in the image and parallel to the first direction D1. In this case, the plurality of line segments parallel to the first direction D1 may be equally spaced from each other in the third direction D3, but the present disclosure is not limited thereto.

[0040] The length of the magnetic assembly 100 in the second direction D2 may refer to: based on an optical microscope image or a scanning electron microscope (SEM) image of a first direction D1-second direction D2 cross section taken from a central portion of the magnetic assembly 100 in the third direction D3, the maximum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of the magnetic assembly 100 shown in the image that are opposite to each other in the second direction D2 and parallel to the second direction D2, the minimum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of the magnetic assembly 100 shown in the image that are opposite to each other in the second direction D2 and parallel to the second direction D2, or the arithmetic mean of at least three dimensions of a plurality of line segments connecting two outermost boundary lines of the magnetic assembly 100 shown in the image that are opposite to each other in the second direction D2 and parallel to the second direction D2. In this case, the plurality of line segments parallel to the second direction D2 may be equally spaced apart from each other in the first direction D1, but the present disclosure is not limited thereto.

[0041] The width of the magnetic assembly 100 in the third direction D3 may refer to: based on an optical microscope image or a scanning electron microscope (SEM) image of a cross section of the first direction D1-third direction D3 taken from a central portion of the magnetic assembly 100 in the second direction D2, the maximum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of the magnetic assembly 100 shown in the image that are opposite to each other in the third direction D3 and parallel to the third direction D3, the minimum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of the magnetic assembly 100 shown in the image that are opposite to each other in the third direction D3 and parallel to the third direction D3, or the arithmetic mean of at least three dimensions of a plurality of line segments connecting two outermost boundary lines of the magnetic assembly 100 shown in the image that are opposite to each other in the third direction D3 and parallel to the third direction D3. In this case, the plurality of line segments parallel to the third direction D3 may be spaced equidistantly from each other in the first direction D1, but the present disclosure is not limited thereto.

[0042] Each of the dimensions of the magnetic component 100 in the first direction D1 to the third direction D3 can be measured using a micrometer measurement method. The micrometer measurement method can be measured using a micrometer with gauge repeatability and reproducibility (R&R) by setting a zero point, inserting the magnetic component 100 according to the present embodiment between the tips of the micrometer, and rotating the measuring rod of the micrometer. When measuring the dimension of the magnetic component 100 using the micrometer measurement method, the dimension of the magnetic component 100 can represent a value measured once or an arithmetic mean of values ​​measured multiple times.

[0043] Reference Figure 3, the magnetic body 101 may include a plurality of magnetic particles 111, and the plurality of magnetic particles 111 include an Fe-based alloy. When the magnetic particles 111 are implemented with an Fe-based alloy, magnetic properties such as a saturation magnetization value may be excellent, but for purposes such as reducing eddy current loss, a first layer 112 may be formed on the surface of at least a portion of the magnetic particles 111 and a second layer 113 may be formed on the surface of the first layer 112. The plurality of magnetic particles 111 may have an average diameter d1 of about 10 μm to 25 μm. In the present embodiment, the Fe-based alloy included in the magnetic particles 111 may include a Fe-Si-BC-based material. More specifically, the Fe-based alloy may not include Cr, Mo, Nb, and P components. These elements may be components that enhance corrosion resistance by slowing down the corrosion progression of the magnetic particles 111. When the content of these elements increases, the Fe content in the Fe-based alloy is relatively reduced, which reduces the saturation magnetization value of the magnetic particles 111. In the present embodiment, an Fe-based alloy including a relatively large content of Fe may be used to ensure sufficient saturation magnetization characteristics, and in this case, by forming the first layer 112 corresponding to the surface oxide film to be very thin, the magnetic particles 111 are allowed to exist in the magnetic body 101 at a sufficient volume fraction. The magnetic particles 111 and the insulating structure (the first layer and the second layer) will be described in more detail later.

[0044] Regarding an example of a manufacturing method, the magnetic body 101 may be formed using a lamination method. Specifically, after forming the coil 103 on the support member 102 using a process such as plating, a plurality of unit stacks for manufacturing the magnetic body 101 may be prepared and stacked. In this case, the unit stack may be prepared in a sheet form by mixing magnetic particles 111 (such as metal, etc.) and an organic material (such as a thermosetting resin, an adhesive, a solvent, etc.) to form a slurry, applying the slurry to a carrier film to a thickness of tens of μm by a doctor blade method, and drying it. Therefore, the unit stack may be manufactured in a form in which the magnetic particles are dispersed in a thermosetting resin (such as an epoxy resin, a polyimide, etc.). The magnetic particles 111 may have the above-mentioned configuration, and the first layer 112 and the second layer 113 may be provided on the surface of the magnetic particles 111. The magnetic body 101 may be realized by stacking a plurality of the above-mentioned unit stacks on the upper and lower parts of the coil 103 and pressurizing them.

[0045] The support member 102 may support the coil 103 and may be formed of polypropylene glycol (PPG), ferrite, a metal soft magnetic member, etc. Figure 2 As shown, a central portion of the support member 102 may be penetrated to form a through hole, and the through hole may be filled with the magnetic body 101 to form the magnetic core portion C.

[0046] The coil 103 may be disposed inside the magnetic body 101 and may perform various functions in the electronic device. For example, the magnetic component 100 may be a power inductor, and in this case, the coil 103 may store power in the form of a magnetic field to maintain an output voltage, thereby stabilizing the power supply. In this case, the coil 103 may be stacked on both surfaces of the support member 102 and may be electrically connected through a conductive via V penetrating the support member 102. The coil 103 may be formed in a spiral shape and may include a lead-out portion L exposed outside the magnetic body 101 in the outermost portion of the spiral shape for electrical connection to the outer electrodes 105 and 106.

[0047] The coil 103 may be disposed on the first surface ( Figure 2 The upper surface in the middle) and the second surface ( Figure 2 As in the present embodiment, the first coil 103a and the second coil 103b may be disposed on the first surface and the second surface of the support member 102, respectively. In this case, the coil 103 may include a pad P. Different from this, the coil 103 may be disposed only on one surface of the support member 102. The coil pattern forming the coil 103 may be formed using a plating process such as pattern plating, anisotropic plating, isotropic plating, etc. used in the art, and may be formed into a multilayer structure using a variety of these processes.

[0048] The external electrodes 105 and 106 may be formed outside the magnetic body 101 to be connected to the lead-out portion L. The external electrodes 105 and 106 may be formed using a paste containing a metal having excellent conductivity, and the paste may be, for example, a conductive paste containing nickel (Ni), copper (Cu), tin (Sn), or silver (Ag) alone or an alloy thereof. In addition, a plating layer may be formed on the external electrodes 105 and 106. In this case, the plating layer may include one or more selected from the group consisting of nickel (Ni), copper (Cu), and tin (Sn), for example, a nickel (Ni) plating layer and a tin (Sn) plating layer may be sequentially formed. Figure 1 In the embodiment, the external electrodes 105 and 106 may have a shape extending from one side surface of the magnetic body 101 to the upper and lower surfaces and the side surfaces, but may be implemented in various other shapes, for example, may have an L-shape.

[0049] The following describes in more detail the plurality of magnetic particles 111 included in the magnetic body 101. The Fe content in the Fe-based alloy included in the magnetic particles 111 may be relatively large and may exceed, for example, 90 wt%. As the Fe content in the Fe-based alloy increases, none of chromium (Cr), molybdenum (Mo), niobium (Nb), and phosphorus (P) may be added, and all of these components may not be added. For more specific composition conditions, the Si content in the Fe-based alloy may be 0.1 wt% to 5 wt%. In addition, the boron (B) content in the Fe-based alloy may be 0.1 wt% to 5 wt%. In addition, the carbon (C) content in the Fe-based alloy may be 0.1 wt% to 2 wt%.

[0050] The average diameter d1 of the magnetic particles 111 may be 10 μm to 25 μm, and the measurement of the average diameter d1 may be performed, for example, from an image of a cross section of the magnetic body 101. As a specific example, for a first direction D1-third direction D3 cross section passing through the center of the magnetic body 101 in the second direction D2, after imaging a plurality of equally spaced regions (e.g., 10 regions) in the first direction D1 with a scanning electron microscope, the average diameter d1 of the magnetic particles 111 may be obtained using an analysis program. In this case, due to a pressurization process or the like, the magnetic particles 111 in the region near the outer surface of the magnetic body 101 may be deformed, or the first layer 112 and the second layer 113 in the region may be destroyed. Therefore, the average diameter d1 may be measured after excluding the magnetic particles 111 in the region near the outer surface of the magnetic body 101. For example, for such a measurement, an area corresponding to a distance from the surface of the magnetic body 101 within 5% or 10% of the length, width, or thickness of the magnetic body 101 may be excluded.

[0051] In the magnetic particles 111 having enhanced saturation magnetization characteristics, the Fe-based alloy included therein may not include corrosion resistance enhancing elements, and a thick oxide film may be formed on the surface of the magnetic particles 111 due to reduced corrosion resistance. The oxide film may correspond to a surface oxide film or a natural oxide film in which the surface of the magnetic particles 111 is oxidized, and its structure may not be dense, so moisture and oxygen may penetrate the oxide film. The oxide film may have a second phase form of Fe oxide, and when the oxide film becomes too thick, the magnetic properties (such as magnetic permeability) of the magnetic body 101 may be reduced. In the present embodiment, the average thickness t1 of the first layer 112 corresponding to the surface oxide layer (i.e., the surface oxide film) may be thinned to a level greater than 0 nm and less than 5 nm, thereby reducing the proportion of the oxide layer on the magnetic particles 111 (or in the entire magnetic particles), whereby the reduction in the magnetic permeability characteristics of the magnetic particles 111 can be minimized. As will be described later, when the average thickness t1 of the first layer 112 is implemented to be thinner than 5 nm, sufficient magnetic permeability can be ensured.

[0052] The first layer 112 may be formed by oxidizing the surface of the magnetic particle 111, and thus may be formed directly on the surface of the magnetic particle 111. In this case, the average thickness t1 of the first layer 112 may be defined as the average distance from the surface of the magnetic particle 111 to the surface of the first layer 112, and may correspond to the average value of the thickness measured in a plurality of regions of the first layer 112. The average thickness t1 of the first layer 112 may be obtained by taking an SEM image or a transmission electron microscope (TEM) image of at least one cross section of the magnetic particle 111, and then measuring the thickness of a plurality of equally spaced regions of the first layer 112. The first layer 112 may include at least one of an Fe-O-based material and an Fe-Si-O-based material. For example, the first layer 112 may include Fe2O3. Unlike the second layer 113, even when the first layer 112 includes an Fe-Si-O-based material, Si may be added in a very small content. For example, the first layer 112 may include an Si component of less than 1 wt%. In addition, the first layer 112 may be formed in an amorphous structure, and therefore, when analyzing its presence or absence, analysis may be performed by composition rather than structure. When a thick natural oxide film is formed on the surface of the magnetic particle 111, crystallization may occur during heat treatment, and the oxide film may react with the second layer 113 including the Si component to form a second phase, thereby reducing magnetic permeability and withstand voltage characteristics.

[0053] Figure 4 It shows how to reduce the thickness of the surface insulating layer in magnetic particles. Figure 4 , the first layer 112 may be initially formed as a thick film layer 112' on the surface of the magnetic particles 111, and then the thickness of the thick film layer 112' may be reduced by a separate etching process. As described above, when the corrosion-resistant element is not added to the Fe-based alloy, the surface oxide film of the thick film layer 112' may be formed thicker (e.g., 20 nm or thicker), which may have an adverse effect on the magnetic properties of the magnetic component 100. In the present embodiment, the thick film layer 112' may be etched to reduce its thickness so that the average thickness t1 of the first layer 112 may be less than 5 nm. As will be described later, when the average thickness t1 of the first layer 112 is less than 5 nm and the average thickness t2 of the second layer 113 is greater than or equal to 5 nm, the magnetic permeability may be fully ensured and the excellent withstand voltage characteristics may be maintained.

[0054] The second layer 113 of the multilayer insulation structure of the present embodiment may be provided to ensure more stable insulation characteristics, and may have an average thickness t2 of 5 nm or more. The upper limit of the average thickness t2 of the second layer 113 may be determined within a range in which magnetic characteristics such as magnetic permeability are not significantly reduced. As an example, the average thickness t2 may be less than 50 nm. The average thickness t2 of the second layer 113 may be defined as the average distance from the surface of the first layer 112 to the surface of the second layer 113, and may be the average value of the thickness measured in multiple regions of the second layer 113. The average thickness t2 of the second layer 113 may be obtained by obtaining an SEM image or a TEM image of at least one cross section of the magnetic particles 111, and then measuring the thickness of multiple equally spaced regions of the second layer 113. The average thickness t2 of the second layer 113 may be thicker than the average thickness t1 of the first layer 112, and may be 2 to 10 times the average thickness t1 of the first layer 112.

[0055] The second layer 113 may include a Si oxide component, and may include, for example, SiO2. In this case, the second layer 113 may include Si in a range from 30wt% to 70wt%. Since the second layer 113 includes Si oxide such as SiO2, the insulating properties of the second layer 113 may be further improved, and the second layer 113 may have a uniform thickness. In the insulating coating materials based on Sn oxide and P oxide that were commonly used in the past, there may be problems such as low uniformity of coating thickness and insufficient withstand voltage characteristics. As in the present embodiment, the insulating properties of the magnetic particles 111 may be improved by the second layer 113 including Si oxide, and further, a saturation magnetization delay effect may be achieved. In addition, as an additional effect, the second layer 113 may have a strong bonding force with the insulating material 110 included in the magnetic body 101. Therefore, high temperature and high humidity reliability may be improved. When the average diameter d1 of the magnetic particles 111 is relatively large (in the range of 10μm to 25μm) as in the present embodiment, the second layer 113 may have a further improved effect in terms of characteristics such as improved withstand voltage. As an example of a method for forming the second layer 113, a liquid coating method may be used. For example, a liquid coating method using tetraethyl orthosilicate (TEOS) may be used, and the second layer 113 may be uniformly coated within a range of several tens of nanometers by hydrolysis using ammonia water as a catalyst.

[0056] In the above example, the method of using the SEM image or the TEM image is shown in measuring the average thickness t1 of the first layer 112 and the average thickness t2 of the second layer 113, but in addition, the thickness can be measured by TEM-EDS analysis. Specifically, after polishing the sample of the magnetic component 100, the cross section of the magnetic particles 111 present in the magnetic body 101 is observed using SEM, and the sample near the surface of the magnetic particles 111 is collected using a focused ion beam (FIB), and the magnetic particles 111 and the insulating structure on the surface thereof can be observed under the conditions of a STEM magnification of 110000 times or more and an acceleration voltage of 200kV. Thus, an EDS line profile scan can be performed from the surface of the magnetic particles 111 to the insulating structure (the first layer and the second layer), and the first layer 112 can be defined as a region ranging from a portion where the content of the Si component decreases rapidly to a portion where the content of the Fe component decreases rapidly. The second layer 113 can be defined as a region ranging from a portion where the content of the Si component increases rapidly to a portion where the content of the Si component decreases rapidly.

[0057] The inventors of the present disclosure prepared samples having different average thicknesses t1 of the first layer 112 and different average thicknesses t2 of the second layer 113, and measured the magnetic permeability and withstand voltage characteristics of the samples. Powder magnetic cores were manufactured and the magnetic permeability and withstand voltage characteristics of the powder magnetic cores were measured, and defect criteria were presented by converting the magnetic permeability according to the powder particle size. As for withstand voltage characteristics, samples having a breakdown voltage greater than or equal to 100 V / mm were marked as "O", and samples having a breakdown voltage less than 100 V / mm were marked as "X".

[0058] [Table 1]

[0059] According to the above experimental results, when the average thickness t1 of the first layer 112 is less than 5 nm and the average thickness t2 of the second layer 113 is greater than or equal to 5 nm, it can be seen that sufficient magnetic permeability (ie, relatively large magnetic permeability) is obtained while also satisfying the withstand voltage characteristics.

[0060] In the following, the following will describe Figure 5 and Figure 6 The variation example shown in . First, in Figure 5In a modified example of , an additional coating may be formed on the surface of the magnetic particles 111. Specifically, a third layer 114 may be formed on the surface of the second layer 113, and, in this case, the third layer 114 may be a surface treatment layer obtained by surface treating the second layer 113. Since the third layer 114 serves as a surface treatment layer, the magnetic particles 111 may have a hydrophobic surface, and the bonding force with the insulating material 110 of the magnetic body 101 may be increased, thereby improving the reliability of the magnetic component 100. As a surface treatment agent for the second layer 113, a material having excellent bonding force with the second layer 113 and the insulating material 110 may be used. For example, at least one of oleic acid and a silane coupling agent may be used, and here, a carbamate-based silane coupling agent may be used as the silane coupling agent.

[0061] The third layer 114 may include at least one functional group selected from the group consisting of an alkyl group, a carbonyl group, and a polyurethane acrylate. In this case, the functional group included in the third layer 114 may be detected using Fourier transform infrared spectroscopy (FT-IR). When the third layer 114, which may be a surface treatment layer, is used, the magnetic body 101 may include at least one component of oleic acid, a derivative of oleic acid, and n-allyl neopentyl carbonate monoamide. In this case, the derivative of oleic acid may include at least one of methyl oleate, butyl oleate, and 3-hydroxypropyl oleate. The components included in the magnetic body 101 may be detected by a gas chromatography-mass spectrometer (GC-MS). As described above, the third layer 114 may be used to improve the bonding force with the insulating material 110 in the magnetic body 101. When the third layer 114 is too thick, the magnetic permeability of the magnetic body 101 is likely to decrease. Therefore, the average thickness t3 of the third layer 114 may be less than 10nm.

[0062] Next, in Figure 6 In a modified example of the present invention, the magnetic body 101 may have a configuration in which additional magnetic particles 121 having a relatively small size are added, and may have a configuration in which the filling rate of the magnetic particles 111 and the additional magnetic particles 121 in the magnetic body 101 is increased. Specifically, the magnetic body 101 may also include additional magnetic particles 121 having an average diameter d2 smaller than an average diameter d1 of the magnetic particles 111 (on which the first layer 112 and the second layer 113 are formed), and the additional magnetic particles 121 may fill the space between the magnetic particles 111 to increase the total content of the magnetic material present in the magnetic body 101. In this case, the average diameter d2 of the additional magnetic particles 121 may be 5 μm or less. The additional magnetic particles 121 may be formed of pure iron, and may be formed of, for example, carbonyl iron particles (CIP). In this case, a coating layer including the first layer 112 and the second layer 113 may not be formed on the surface of the additional magnetic particles 121.

[0063] Will refer to Figures 7 to 9Another embodiment of the present disclosure is described. In the previous embodiment, the coil 103 and the support member 102 supporting the coil 103 may be provided in the magnetic body 101, and Figures 7 to 9 Embodiments may use a winding coil. The structure is described below, and the magnetic component 200 may include a molding portion 250, a coil 230, a covering portion 211, and accommodating grooves h1 and h2, and may also include external electrodes 270 and 280. The magnetic body may form the exterior of the magnetic component 200, and the coil 230 may be encapsulated in the magnetic body. The magnetic body may include a molding portion 250 and a covering portion 211. The molding portion 250 may include a core 220. The magnetic body may be formed as a whole to have a hexahedral shape. The magnetic body may have a first surface 201 and a second surface 202 opposite to each other in a first direction D1, a third surface 203 and a fourth surface 204 opposite to each other in a third direction D3, and a fifth surface 205 and a sixth surface 206 opposite to each other in a second direction D2. The third surface 203 to the sixth surface 206 of the magnetic body may correspond to the wall surface of the magnetic body connecting the first surface 201 and the second surface 202 of the magnetic body.

[0064] The magnetic body may be configured, for example, so that the magnetic assembly 200 according to the present embodiment, on which the outer electrodes 270 and 280 to be described later are formed, has a length of 2.0 mm, a width of 1.2 mm, and a thickness of 0.6 mm, but the present disclosure is not limited thereto. The magnetic body may include a molding part 250 and a covering part 211. The covering part 211 may be disposed on the upper part of the molding part 250 and may surround all surfaces except the lower surface of the molding part 250. The molding part 250 may have one surface and another surface opposite to each other. The one surface of the molding part 250 may correspond to the lower surface of the molding part 250 and may refer to an area in which the receiving grooves h1 and h2 to be described later are disposed. As will be described later, since the receiving grooves h1 and h2 may be processed inside the molding part 250, the lower surface of the receiving grooves h1 and h2 may be disposed in an area between the aforementioned one surface and the other surface of the molding part 250. The molding part 250 may include a support part 210 and a core 220. The core 220 may be disposed in a central portion of the other surface of the support portion 210 in a manner penetrating the coil 230. The molding portion 250 may be formed by filling a mold with a composite material including magnetic particles (such as the magnetic particles 111 including the first layer 112 and the second layer 113) and an insulating resin. In this case, the insulating resin may include epoxy resin, polyimide, liquid crystal polymer, etc., alone or in combination, but the present disclosure is not limited thereto.

[0065] The coil 230 may be encapsulated in a magnetic body to present the characteristics of the magnetic component 200. For example, when the magnetic component 200 of the present embodiment is used as a power inductor, the coil 230 may play a role in stabilizing the power supply of the electronic device by storing the electric field as a magnetic field and maintaining the output voltage. The coil 230 may be disposed on the other surface of the molded portion 250. Specifically, the coil 230 may be wound around the core 220 and may be disposed on the other surface of the support portion 210. The coil 230 may be an air-core coil and may be disposed as a square coil. The coil 230 may be formed by winding a metal wire such as a copper wire whose surface is covered with an insulating material into a spiral shape. The coil 230 may be disposed in a plurality of layers. Each layer of the coil 230 may be formed in a planar spiral shape and may have a plurality of turns. For example, the coil 230 may form the innermost turn T1, at least one intermediate turn T2, and the outermost turn T3 from the central portion of the other surface of the molded portion 250 in an outward direction.

[0066] The covering part 211 may be disposed on the molding part 250 and the coil 230. The covering part 211 may cover the molding part 250 and the coil 230. The covering part 211 may be disposed on the support part 210 and the core 220 of the molding part 250 and the coil 230, and then may be pressurized to be bonded to the molding part 250. The molding part 250 and the covering part 211 may include magnetic particles 111, respectively, in which case, as described above, the first layer 112 and the second layer 113 may be formed on the surface of the magnetic particles 111.

[0067] The first receiving groove h1 and the second receiving groove h2 may be formed on one surface of the molding part 250 to be spaced apart from each other, and the two ends of the coil 230 to be described later may be disposed in the first receiving groove h1 and the second receiving groove h2. For example, the first receiving groove h1 and the second receiving groove h2 may be respectively formed on one surface of the molding part 250, and may be spaced apart from each other in the second direction D2. The first receiving groove h1 and the second receiving groove h2 may be disposed outside the region corresponding to the core 220 on one surface of the molding part 250, but the present disclosure is not limited thereto. Each of the first receiving groove h1 and the second receiving groove h2 may be formed to extend in one direction (e.g., the third direction D3) on one surface of the molding part 250, but may be formed in any shape without limitation as long as it has a structure that effectively exposes the two ends of the coil 230.

[0068] Since the magnetic body may be a region including the molded portion 250 and the cover portion 211, one surface of the magnetic body may refer to one surface of the region including the molded portion 250 and the cover portion 211. The coil 230 may be led out to the outside, and may include a first lead-out portion and a second lead-out portion respectively disposed in the first receiving groove h1 and the second receiving groove h2. The first receiving groove h1 and the second receiving groove h2 may be regions where both ends of the coil 230 are led out to the external electrodes 270 and 280, and thus may be spaced apart from each other to correspond to the first external electrode 270 and the second external electrode 280, respectively, and may be formed on one surface of the magnetic body.

[0069] As an example, the through grooves H1 and H2 may be formed by a mold when forming the molding part 250, and the first receiving groove h1 and the second receiving groove h2 may be formed in the molding part 250, and the covering part 211 may be formed on the molding part 250 by stacking and pressing the magnetic sheet including the metal magnetic particles. Protrusions corresponding to the through grooves H1 and H2 may be formed in the mold for forming the molding part 250, and the through grooves H1 and H2 may be formed in the molding part 250, and the molding part 250 may be manufactured to have a shape corresponding to the shape of the mold. In addition, the first receiving groove h1 and the second receiving groove h2 may not be formed in the process for forming the molding part 250, but may be formed in the process for forming the covering part 211 on the molding part 250. For example, both ends of the coil 230 protruding from one surface of the molding part 250 through the through grooves H1 and H2 of the molding part 250 may be bent in a horizontal direction (e.g., the third direction D3), and then the bent portion may be buried inside the molding part 250 from one surface of the molding part 250 in a process for pressing the magnetic sheet. Therefore, the first and second receiving grooves h1 and h2 may be formed on one surface of the molding part 250. Alternatively, the first and second receiving grooves h1 and h2 and the through grooves H1 and H2 may be formed in a process of forming the molding part 250 using a mold. In this case, protrusions corresponding to the first and second receiving grooves h1 and h2 and the through grooves H1 and H2 may be formed in a mold for forming the molding part 250.

[0070] The two ends of the coil 230 may pass through one surface of the molding part 250 and may be respectively disposed in the first receiving groove h1 and the second receiving groove h2. Since the shape of the ends of the coil 230 disposed in the receiving grooves h1 and h2 may not be limited, the widths of the first receiving groove h1 and the second receiving groove h2 may be the same as or different from the widths of the through grooves H1 and H2. The two ends of the coil 230 may be exposed to one surface of the molding part 250, for example, to the second surface 202 of the magnetic body. The two ends of the coil 230 exposed to one surface of the molding part 250 may be disposed in the first receiving groove h1 and the second receiving groove h2, and the first receiving groove h1 and the second receiving groove h2 are formed to be spaced apart from each other on the second surface 202 of the magnetic body. The two ends of the coil 230 may pass through the support part 210 of the molding part 250 and may be exposed to one surface of the support part 210. Although not specifically shown, the thickness of both ends of the coil 230 may be the same as the thickness of the coil 230, and thus may protrude from one surface of the support portion 210 by a distance corresponding to the thickness of the coil 230. Since the protruding ends of the coil 230 may also be polished in a process of polishing the openings of the plating resist for forming the external electrodes 270 and 280, which will be described later, the ends of the coil 230 exposed on one surface of the support portion 210 may be substantially smaller than the thickness of the coil 230.

[0071] The external electrodes 270 and 280 may be arranged to be spaced apart from each other on one surface (e.g., the second surface 202) of the magnetic body. Specifically, the external electrodes 270 and 280 may be arranged to be spaced apart from each other on one surface of the molded portion 250, and may be connected to both ends of the coil 230 disposed in the first receiving groove h1 and the second receiving groove h2, respectively. Since both ends of the coil 230 may be disposed along the lower surfaces of the first receiving groove h1 and the second receiving groove h2, and the external electrodes 270 and 280 may be formed along both ends of the coil 230, the external electrodes may be formed to correspond to the shapes of the first receiving groove h1 and the second receiving groove h2. As an example, a conductive resin including conductive particles such as silver (Ag) or the like may be applied to the first receiving groove h1 and the second receiving groove h2 to form the external electrodes 270 and 280. As an example, the external electrodes 270 and 280 may be formed using a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), chromium (Cr), titanium (Ti), or an alloy thereof, but the present disclosure is not limited thereto. The external electrodes 270 and 280 may be formed as a single layer or multiple layers.

[0072] The magnetic component 200 according to the present embodiment may further include an insulating layer 290 surrounding the surface of the coil 230. There may be no limitation on the process of forming the insulating layer 290, for example, the insulating layer 290 may be formed by chemical vapor deposition of polyparaxylene resin or the like on the surface of the coil 230, and may be formed by known methods such as a screen printing process, photoresist (PR) exposure, a development process, a spraying process, a dipping process, etc. The insulating layer 290 is not particularly limited as long as it can be formed as a thin film, for example, may include, for example, a photoresist (PR), an epoxy resin, etc.

[0073] A magnetic assembly according to examples of the present disclosure may have excellent magnetic characteristics, such as a high level of magnetic permeability, saturation flux characteristics, and the like.

[0074] While example embodiments have been shown and described above, it will be readily apparent to those skilled in the art that modifications and variations may be made without departing from the scope of the present disclosure as defined by the appended claims.

Claims

1. A magnetic assembly, comprising: Magnetic body, Wherein, the magnetic body comprises a plurality of magnetic particles, and the plurality of magnetic particles comprises an Fe-based alloy, A first layer is formed on the surface of at least a portion of the plurality of magnetic particles and a second layer is formed on the surface of the first layer, The first layer comprises an Fe oxide component and has an average thickness of less than 5 nm, and The second layer includes a Si oxide component and has an average thickness of 5 nm or more.

2. The magnetic assembly according to claim 1, wherein: The first layer includes a Si component of less than 1 wt %.

3. The magnetic assembly according to claim 1 or 2, wherein: The second layer includes 30 wt % to 70 wt % of Si component.

4. The magnetic assembly according to claim 1, wherein: The average thickness of the second layer is less than 50 nm.

5. The magnetic assembly according to claim 1, wherein: The average thickness of the second layer is 2 to 10 times the average thickness of the first layer.

6. The magnetic assembly according to claim 1, wherein: The plurality of magnetic particles have an average diameter of 10 μm to 25 μm.

7. The magnetic assembly according to claim 1, wherein: A third layer is formed on a surface of the second layer.

8. The magnetic assembly according to claim 7, wherein: The third layer includes at least one functional group of an alkyl group, a carbonyl group, and a urethane acrylate.

9. The magnetic assembly according to claim 7, wherein: The magnetic host includes at least one of oleic acid, a derivative of oleic acid, and n-allyl neopentyl carbonate monoamide.

10. The magnetic assembly of claim 7, wherein: The average thickness of the third layer is less than 10 nm.

11. The magnetic assembly of claim 1, wherein: The Fe-based alloy includes a Fe-Si-BC-based material.

12. The magnetic assembly of claim 11, wherein: The Fe-based alloy does not include Cr, Mo, Nb and P components.

13. The magnetic assembly of claim 11, wherein: The Fe content in the Fe-based alloy exceeds 90 wt %.

14. The magnetic assembly of claim 13, wherein: The Si content in the Fe-based alloy is 0.1 wt % to 5 wt %.

15. The magnetic assembly of claim 1, wherein: The magnetic body further includes additional magnetic particles having an average diameter smaller than an average diameter of the plurality of magnetic particles.

16. The magnetic assembly of claim 15, wherein: The additional magnetic particles include carbonyl iron particles.

17. A magnetic particle comprising: A core, including an Fe-based alloy; a first layer disposed on a surface of the core, the first layer comprising an Fe oxide component and having an average thickness of less than 5 nm; as well as A second layer is provided on a surface of the first layer, the second layer includes a Si oxide component, and an average thickness of the second layer is 2 to 10 times the average thickness of the first layer.

18. The magnetic particle according to claim 17, wherein The second layer has an average thickness of at least 5 nm.

19. The magnetic particle according to claim 17, wherein The average diameter of the core is in the range of 10 μm to 25 μm. 20 . The magnetic particle of claim 17 , further comprising a third layer disposed on a surface of the second layer and comprising at least one functional group of an alkyl group, a carbonyl group, and urethane acrylate.

21. The magnetic particle according to claim 20, wherein The average thickness of the third layer is less than 10 nm.

22. The magnetic particle according to claim 17, wherein The Fe-based alloy includes a Fe-Si-BC-based material and does not include Cr, Mo, Nb, and P components.

23. The magnetic particle according to claim 17, wherein The Si content in the first layer is less than 1 wt %, and the Si content in the second layer is in a range of 30 wt % to 70 wt %.

24. A magnetic component, comprising a coil and a magnetic body comprising a magnetic core, wherein the coil is wound around the magnetic core and encapsulated in the magnetic body, wherein: At least a portion of the magnetic body comprises magnetic particles according to any one of claims 17 to 23.

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