Coil component, coil component production method, and electronic / electrical apparatus

Abstract

A coil component 100 according to the present invention, in which a coating-type electrode has appropriate detachment strength even when the size of a body section is reduced, comprises: a coil 10; a body section 30 including a magnetic powder 31 and a binder 32 and having a portion located in a range of an induced magnetic field generated when the coil 10 is energized; coating-type electrodes 401, 451 electrically connected to the coil 10, provided so as to cover a part of the body section 30, and including a conductive material; and an interposed layer 50 located between the body section 30 and the coating-type electrodes 401, 451 and composed of a powder dispersion resin. In the interposed layer 50, the surface roughness of a surface (first surface 50A) facing the coating-type electrodes 401, 451 is greater than the surface roughness of a surface (second surface 50B) facing the body section 30.

Description

Coil component, coil component manufacturing method, and electronic / electrical equipment

[0001] The present invention relates to a coil component such as a chip inductor in which a coil is embedded in a magnetic core, a method for manufacturing a coil component, and an electronic / electrical device.

[0002] Patent Document 1 describes an inductor having a coil wound with a conductive metal material coated with an insulating material, a pair of terminal plates extending from the coil, and a magnetic core with at least the coil embedded therein, wherein one end of each of the pair of terminal plates is located outside the magnetic core, and the inductor further comprises a pair of coated electrodes electrically connected to each of the pair of terminal plates, each of the pair of coated electrodes having a side coated portion provided on a part of the side of the magnetic core with the direction along the winding axis of the coil as the in-plane direction, the magnetic core being an aggregate of magnetic powder, and wherein the density of the magnetic powder located in a first region of the magnetic core consisting of a region outside the outer side of the coil and a region on the outer periphery of a curved surface obtained by extending the outer side of the coil in a direction along the winding axis of the coil is lower than the density of the magnetic powder located in a second region of the magnetic core consisting of a region inside the inner side of the coil and a region on the inner periphery of the curved surface obtained by extending the inner side of the coil in a direction along the winding axis of the coil.

[0003] Patent Document 2 describes a method for manufacturing a surface-mounted inductor, which comprises winding a conductor to form a coil, encapsulating the coil using a sealing material mainly consisting of metal magnetic powder and resin, forming a core portion so that at least a portion of both ends of the coil are exposed on its surface, reducing the surface smoothness of at least a portion of the portion of the core portion where an external electrode is formed compared to the smoothness of the surrounding surface, and forming an external electrode that is electrically connected to the coil on the core portion.

[0004] JP 2017-11042 A JP 2014-225590 A

[0005] Inductors having a structure in which a coil is embedded in a magnetic core, such as the inductor described in Patent Document 1, are widely used as components for driving the display units of mobile communication terminals such as smartphones. There is a continuing demand for thinner and more compact mobile communication terminals, and there is also a continuing demand for improved display performance, such as increasing maximum display brightness. Against the backdrop of these demands, such inductors, also known as chip inductors, are increasingly being demanded for miniaturization, including lower height.

[0006] In response to such demands, as described in Patent Document 1, chip inductors sometimes use a pair of coated electrodes as connection terminals connected to an embedded coil. When the size of the magnetic core is particularly reduced, there is a concern that the adhesive strength of these coated electrodes to the magnetic core will decrease. Therefore, as described in Patent Document 2, measures can be considered to reduce the surface smoothness of at least a portion of the core portion (magnetic core) where the external electrodes (coated electrodes) are formed. Patent Document 2 exemplifies removal processing methods such as laser, blasting, and polishing as methods for reducing the smoothness of the magnetic core.

[0007] However, as coil components such as chip inductors become smaller, the surface area of ​​the magnetic core (main body) becomes significantly smaller, making it extremely difficult to irradiate a portion of the surface with a laser, perform blasting, or polish it. Furthermore, when the main body is subjected to a removal process, part of the material constituting the main body is removed, reducing the amount of magnetic powder constituting the main body, which can lead to problems such as reduced coil component performance and defective products, or the coil embedded in the main body being unexpectedly exposed, resulting in defective products. If the degree of removal is reduced to avoid these problems, the adhesion of the coated electrode can be reduced, leading to the electrode peeling off from the main body and resulting in defective products.

[0008] The present invention aims to provide a coil component in which a coated electrode has appropriate peel strength even when the size of the magnetic core (main body) is reduced, a method for manufacturing the coil component, and an electronic / electrical device.

[0009]

[0009] One aspect of the present invention, which is intended to solve the above-described problems, is a coil component comprising: a coil; a main body including a magnetic powder and a binder, the main body including a portion positioned within a range of an induced magnetic field generated when current is applied to the coil; a coated electrode including a conductive material, electrically connected to the coil and disposed so as to cover a portion of the main body; and an intervening layer between the main body and the coated electrode, the intervening layer being made of a powder-dispersed resin, the intervening layer having a surface roughness facing the coated electrode that is greater than the surface roughness of the surface facing the main body. Since the intervening layer made of the powder-dispersed resin contacts the coated electrode instead of the main body, the contact area between the coated electrode and the powder-dispersed resin is greater than the contact area between the coated electrode and the main body, thereby increasing the peel strength of the coated electrode.

[0010] In the coil component described above, the powder-dispersed resin may contain a powder and a matrix material. In this case, when a cross section of the intervening layer is observed and the volume particle size distribution of the powder is calculated from the equivalent circle diameter of the cross section of the powder located in an observation field, a 50% cumulative particle diameter D50 in the volume particle size distribution and an average thickness Ti of the intervening layer in the observation field may satisfy the following formula (1): Ti / D50≦20 (1)

[0011] In the coil component described above, the binder may contain a thermally denatured resin or the like, and in this case, the main body may have an impregnated coating resin near the surface that fills at least a portion of the pores formed when the thermally denatured resin or the like is generated.

[0012] In the coil component described above, the main body may have a portion made of a powder-pressed compact having a mounting surface that faces a substrate when mounted and a side surface that intersects with the mounting surface, and in this case, the surface roughness of the mounting surface may be greater than the surface roughness of the side surface. Even in such a case, the presence of the intervening layer makes it possible to appropriately increase the peel strength of the coated electrode located on the side surface of the main body.

[0013] In the coil component described above, when the side surface is composed of a plurality of surfaces, the area of ​​the mounting surface may be larger than any of the areas of the plurality of surfaces. When the intermediate layer is formed by spray coating, such an area relationship makes it easy to increase the surface roughness of the intermediate layer provided on the side surface.

[0014] In another aspect, the present invention provides a method for manufacturing a coil component having an intervening layer made of a powder-dispersed resin containing a powder and a matrix material, the method including spraying a powder-dispersed resin composition containing a thermosetting resin that provides the matrix material and the powder onto the main body and curing the thermosetting resin adhered to the main body to form the intervening layer, and applying a conductive-material-containing resin composition containing the conductive material so as to cover a portion of the intervening layer to form the coated electrode.

[0015] In the above manufacturing method, the magnetic powder dispersion resin composition containing the magnetic powder and the coil may be placed in a cavity of a mold and compacted to form a compacted powder molded body, the compacted powder molded body may be heated to thermally decompose at least a portion of the resin contained in the magnetic powder dispersion resin composition, thereby forming the binder containing the thermal decomposition residue of the resin in the main body portion and generating pore portions, an impregnating coating resin may be placed so as to fill at least a portion of the pore portions, and the powder dispersion resin composition may be sprayed onto the main body portion having the impregnating coating resin.

[0016] In another aspect, the present invention provides an electronic / electrical device including a substrate on which the above-mentioned coil component is mounted, wherein the coated electrode of the coil component is electrically connected to a terminal provided on the substrate.

[0017] According to the present invention, there are provided a coil component in which the coated electrode is not easily peeled off, a method for manufacturing the coil component, and an electronic / electrical device.

[0018] 1 is an XZ cross-sectional view taken along line A-A' in FIG. 1; FIG. 2 is an enlarged view of the area surrounded by the thick dashed line in FIG. 2; FIG. 3 is an observation image of a portion of a cross section (including the cross section line of the side surface of the main body) obtained by cutting an example of a coil component according to the present embodiment along an XZ plane including line A-A' in FIG. 1; FIG. 4 is an observation image of a portion of a cross section (including the cross section line of the bottom surface of the main body) obtained by cutting an example of a coil component according to the present embodiment along an XZ plane including line A-A' in FIG. 1; FIG. 5 is an observation image of a portion of a cross section (including the cross section line of the bottom surface of the main body) obtained by cutting an example of a coil component according to the present embodiment along an XZ plane including line A-A' in FIG. 1; FIG. 6 is an enlarged view of the area surrounded by the thick dashed line in FIG. 2, illustrating in detail the structure of the main body; FIG. 7 is an explanatory view of a manufacturing process for a main body having the structure shown in FIG. 7, illustrating a state after a molding process; FIG. 8 is an explanatory view of a manufacturing process for a main body having the structure shown in FIG. 7, illustrating a state after a heating process. 8 is a diagram illustrating the manufacturing process of a main body having the structure shown in FIG. 7, showing the state after the impregnation coating process is completed. FIG. 9 is an exploded perspective view illustrating the structure of a temporary assembly. FIG. 10 is a cross-sectional view illustrating the process of manufacturing a molded body using the temporary assembly. FIG. 11 is an observation result after a peel test of the bottom surface of one of the coil components according to the example. FIG. 12 is an observation result after a peel test of the bottom surface of one of the comparison coil components according to the comparative example. FIG. 13 is a measurement result of the peel strength. FIG. 14 is a measurement result of the area of ​​the coated electrode after the test.

[0019] Hereinafter, chip inductors according to embodiments of the present invention will be described in detail with reference to the drawings.

[0020] FIG. 1 is a perspective view showing, with some transparency, the overall configuration of a coil component according to an embodiment of the present invention. FIG. 2 is an XZ cross-sectional view taken along line A-A' in FIG. 1. In each figure, X-Y-Z coordinates are shown as reference coordinates. The X-Y plane, which includes the X1-X2 direction and the Y1-Y2 direction, is a plane perpendicular to the Z1-Z2 direction. In the following description, the Y1 direction may be referred to as the front side, the Y2 direction as the rear side, the X1 direction as the left side, the X2 direction as the right side, the Z1 direction as the upper side, and the Z2 direction as the lower side; however, these directions can be set arbitrarily depending on the posture of the coil component 100, etc.

[0021] As shown in FIG. 1 , a coil component 100 according to an embodiment of the present invention has a structure in which a coil 10 is embedded in a main body 30 having an approximately rectangular parallelepiped outer shape. The main body 30 has a portion located within the range of an induced magnetic field generated when the coil 10 is energized. In the example shown in FIG. 1 , the portion of the coil 10 other than its external electrical connection portion is embedded in the main body 30. The coil 10 is, for example, an edgewise coil formed by winding a conductive strip made of a conductive metal material coated with an insulating material and having a rectangular cross section. The coil 10 is wound such that the plate surface of the conductive strip is approximately perpendicular to the vertical direction (Z1-Z2 direction) along the winding axis O, and the side end surfaces of the conductive strip, which determine the thickness direction of the coil 10, are parallel to the winding axis O, and the plate surfaces of the conductive strip overlap along the winding axis O. Therefore, the normal to the upper and lower end surfaces of the coil 10 (both end surfaces in the Z1-Z2 direction) is the direction along the winding axis O of the coil 10. As shown in FIG. 1, the coil 10 is wound such that the conductive band has a perfect circular shape when viewed in a plan view along the vertical direction (Z1-Z2 direction).

[0022] Here, the planar shape of the winding of the coil 10 is not limited to a perfect circle, and may be, for example, an ellipse or an oval, and can be appropriately selected by a person skilled in the art. Furthermore, the cross-sectional shape of the coil 10 is not limited to a rectangle, and may be, for example, a circle. A rectangular cross-sectional shape such as a rectangle as described above is preferable because it allows for a higher occupancy rate of the coil 10.

[0023] The specific composition of the conductive metal material constituting the coil 10 is not limited, and is preferably a good conductor such as copper, copper alloy, aluminum, or aluminum alloy. The type of insulating material coating the conductive metal material is not limited. Specific examples of suitable materials include resin-based materials such as enamel. The shape of the coil 10 is also not limited. For example, it may be an edgewise coil or an alpha-wound coil. Furthermore, the coil 10 may be formed using a thin film formation method such as plating. When the coil 10 is an edgewise coil, the insulating material located on the outer surface side is easily stretched, so it is preferable to use a material whose insulating properties are not easily reduced even when stretched.

[0024] When the coil 10 is wound into a perfect circle, both ends of the conductive band that constitutes the coil 10 each protrude and are then folded back, with the portions of the conductive band near the ends forming a pair of terminal plates (first terminal plate 20, second terminal plate 25). At least a portion of the surfaces of the pair of terminal plates (first terminal plate 20, second terminal plate 25) is not covered with an insulating coating, allowing electrical conduction to the outside.

[0025] As shown in FIG. 1 , one end of the conductive strip constituting the coil 10 is first bent at a substantially right angle in a valley fold direction, then bent at a substantially right angle in a mountain fold direction, and then bent again at a substantially right angle in the valley fold direction, with the portion from this final bend to the end of the conductive strip constituting the first terminal plate 20. At one end of the conductive strip constituting the coil 10, a portion 11 between the mountain fold and the second valley fold is exposed to the outside at a side surface 30B on the front side (Y1 side in the Y1-Y2 direction) of the main body 30. The portion that is valley-folded from this portion 11 to the end of the conductive strip extends along the front-rear direction (Y1-Y2 direction) as the first terminal plate 20 and is exposed to the outside from the main body 30 at a bottom surface 30A, which is the upper side surface of the main body 30, i.e., a plane normal to the Z1-Z2 direction along the winding axis O of the coil 10. The main body 30 has a top surface 30E, which is a lower side surface that faces the bottom surface 30A in the vertical direction (Z1-Z2 direction) (FIG. 1). The bottom surface 30A is the mounting surface that faces the board when mounted.

[0026] As shown in FIG. 1 , the other end of the conductive band constituting coil 10 is first folded at approximately right angles in a mountain fold direction, and then folded three times at approximately right angles in a valley fold direction, with the portion from this final fold to the end of the conductive band constituting second terminal plate 25. At the other end of the conductive band constituting coil 10, a portion 12 between the second valley fold and the third valley fold is exposed on the front side surface 30B of main body 30. The portion from this portion 12 to the end of the conductive band extends along the front-to-rear direction as second terminal plate 25 and is exposed to the outside from main body 30 on bottom surface 30A of main body 30, i.e., on a plane normal to the Z1-Z2 direction along winding axis O of coil 10.

[0027] Although the coil 10 and the pair of terminal plates (first terminal plate 20, second terminal plate 25) are made of the same material (conductive band), this is not limitative. Separate members may be joined to the ends of the conductive band that makes up the coil 10, and these members electrically connected to the coil 10 may make up the pair of terminal plates (first terminal plate 20, second terminal plate 25).

[0028] In the coil device 100, a pair of external electrodes 40, 45 are formed on both ends of the bottom surface 30A of the main body 30 in the left-right direction (X1-X2 direction). The external electrode 40 is provided so as to cover a portion of each of the bottom surface 30A, the side surface 30C on the X1 side in the X1-X2 direction, and the two side surfaces 30B, 30F on the Y1-Y2 direction of the main body 30. The external electrode 45 is provided so as to cover a portion of each of the bottom surface 30A, the side surface 30D on the X2 side in the X1-X2 direction, and the two side surfaces 30B, 30F on the Y1-Y2 direction of the main body 30. Because the main body 30 is a substantially rectangular parallelepiped, each of the above-mentioned side surfaces intersects with the bottom surface 30A.

[0029] 2 , the external electrode 40 has a coating-type electrode 401 proximal to the main body 30 and a plating electrode 402 formed on the coating-type electrode 401. Like the external electrode 40, the external electrode 45 has a coating-type electrode 451 proximal to the main body 30 and a plating electrode 452 formed on the coating-type electrode 451.

[0030] Fig. 3 is an explanatory diagram of the structure of the region surrounded by the thick dashed line in Fig. 2. As shown in Fig. 2 and Fig. 3, an intervening layer 50 made of a powder-dispersed resin is provided between the main body 30 and the coating-type electrodes 401, 451. The powder-dispersed resin constituting the intervening layer 50 includes a powder 51 and a matrix material 52.

[0031] The intervening layer 50 made of powder-dispersed resin has a surface roughness (first surface 50A) facing the coated electrodes 401, 451 that is greater than the surface roughness (second surface 50B) facing the main body 30. Therefore, the coated electrodes 401, 451 formed on the intervening layer 50 are less likely to peel off from the main body 30, and the coil component 100 is less likely to experience problems such as peeling of the external electrodes 40, 45 including the coated electrodes 401, 451.

[0032] Since the powder 51 is intended to increase the surface roughness of the first surface 50A of the intervening layer 50, the material constituting the powder 51 is not limited. The material constituting the powder 51 may be magnetic or non-magnetic, and may be conductive or insulating. However, a material having appropriate insulating properties as a powder dispersion resin is preferable because it makes it easier to select a manufacturing method for forming the intervening layer 50 over the entire surface of the main body 30 and then forming the coated electrodes 401, 451 in predetermined positions.

[0033] The shape of the powder 51 is also arbitrary, and may be a shape close to a sphere, or may be another shape, such as a needle, a scale, or an irregular shape.

[0034] The material constituting the matrix material 52 is not limited as long as it contains a resin material. As described above, a powder-dispersed resin having suitable insulating properties tends to provide greater flexibility in the manufacturing method, so it is preferable that the matrix material 52 be insulating. The type of resin-based material contained in the insulating matrix material 52 is not limited, and may be thermosetting, including epoxy resin, phenolic resin, etc., or thermoplastic, including polyolefin, polyester, acrylic resin, etc.

[0035] 4 and 5 are observation images of a portion of a cross section obtained by cutting an example of a coil component according to this embodiment along an XZ plane including line A-A' in Fig. 1. The cross section shown in Fig. 4 is a cross section including a cross section line of the side surface 30C of the main body portion 30, and the cross section shown in Fig. 5 is a cross section including a cross section line of the bottom surface 30A of the main body portion 30.

[0036] For both cross sections, it is immediately apparent that the first cross section line formed by the first surface 50A in the observed cross section of the interposed layer 50 has more irregularities than the second cross section line formed by the second surface 50B in the observed cross section. Based on these observation images, the maximum cross section roughness Rt of the first cross section line and the second cross section line was measured. Hereinafter, the measurement position shown in Figure 4 will be referred to as "measurement position 1," and the measurement position shown in Figure 5 will be referred to as "measurement position 2." The results are shown in Table 1.

[0037] Furthermore, the ratio (L1 / L2) of the line length (L1) of the first cross-sectional line measured along the irregularities to the line length (L2) of the second cross-sectional line measured along the irregularities can be used to estimate the degree to which the first cross-sectional line is more irregular than the second cross-sectional line. This ratio (first parameter P1) and a second parameter P2 obtained by squaring the first parameter P1 were calculated for the results at the two measurement positions. The second parameter P2 can be used to estimate the ratio of the actual area of ​​the first surface 50A, including the irregularities, to the actual area of ​​the second surface 50B, including the irregularities.

[0038]

[0039] As shown in Table 1, the actual area of ​​first surface 50A, including the irregularities, is estimated to be approximately 1.3 to 1.5 times the actual area of ​​second surface 50B, including the irregularities. This increase in area is thought to result in an improvement in the peel strength of coated electrodes 401, 451 in coil device 100 according to this embodiment.

[0040] Cross-sectional observation was also performed on a coil component according to the prior art that did not have the intervening layer 50. The results are shown in FIG. 6. When performing cross-sectional observation, the coil component is cut and polished to obtain an observation sample for cross-sectional observation. As shown in FIG. 6, in the coil component that does not have the intervening layer 50, a peeled portion G occurs between the main body 30 and the coated electrode 401 due to the external force applied during the cutting and polishing processes when preparing the observation sample. A specific example of the process for preparing the observation sample is as follows: Resin embedding: epoxy resin at 120°C for 20 minutes Polishing (cutting): cutting with a #400 or #2000 polishing plate rotating at 350 rpm using a small precision sample preparation system CP (polishing): ion milling (accelerating voltage 6 kV, 5.5 hours)

[0041] From the viewpoint of stably realizing that the surface roughness of the first surface 50A of the intervening layer 50 is greater than the surface roughness of the second surface 50B, when the volume particle size distribution of the powder 51 is calculated from the equivalent circle diameter of the cross section of the powder 51 located in the observation field by observing the cross section of the intervening layer 50, it is preferable that the 50% cumulative particle diameter D50 in the volume particle size distribution and the average thickness Ti of the intervening layer 50 in the observation field satisfy the following formula (1): Ti / D50≦20 (1)

[0042] When the above formula (1) is satisfied, the powder 51 is likely to contribute to imparting appropriate roughness to the intervening layer 50. Ti / D50 may be more preferably 15 or less, even more preferably 10 or less, particularly preferably 8 or less, and extremely preferably 6 or less.

[0043] From the viewpoint of stably realizing that the surface roughness of the first surface 50A of the intervening layer 50 is greater than the surface roughness of the second surface 50B, there is no lower limit for Ti / D50, but if Ti / D50 is less than 1, it becomes difficult for the matrix material 52 to stably hold the powder 51, which raises concerns that the intervening layer 50 itself may become unstable. Therefore, it is preferable that Ti / D50 be 1 or greater.

[0044] Ti and D50 were measured at the two measurement positions described above, and Ti / D50 was calculated from these measurement results. The results are shown in Table 2.

[0045]

[0046] As shown in Table 2, it was confirmed that Ti / D50 was between 5 and 6 at all measurement positions.

[0047] Any material may be used to form the coated electrodes 401, 451 as long as it has appropriate conductivity. A conductive paint, which is made by dispersing a conductive material, typically a metal material such as silver or aluminum, in a powder state in a solvent (vehicle), is applied to predetermined positions on the intervening layer 50 by a method such as printing, and the solvent is volatilized by heating or the conductive material is baked, thereby forming the coated electrodes 401, 451 on the intervening layer 50.

[0048] From the viewpoint of more stably increasing the conductivity of the external electrodes 40, 45 including the coated electrodes 401, 451, the coil component 100 according to this embodiment includes, as an example, plated electrodes 402, 452 on the coated electrodes 401, 451. The material from which the plated electrodes 402, 452 are formed is not limited. Examples of metal elements contained in the material include copper, aluminum, zinc, nickel, iron, and tin. When the external electrodes 40, 45 include the coated electrodes 401, 451 and the plated electrodes 402, 452, the amount of conductive paint applied to form the coated electrodes 401, 451 is set to 0.05 g / cm. 2 The thickness of the plating electrodes 402, 452 is exemplified as being in the range of about 5 to 10 μm.

[0049] As shown in Fig. 7 (described later) and other figures, the main body 30 includes magnetic powder 31 and a binder 32. The magnetic powder 31 is preferably a ferromagnetic material, and more preferably a soft magnetic material. The magnetic powder 31 may include a metallic portion, or may include a portion made of a non-metallic material such as ferrite.

[0050] When the magnetic powder 31 contains a metallic portion, the structure of the metallic portion is not limited. This structure may include a crystalline phase or an amorphous phase. Here, a crystalline material is defined as a material consisting of a crystalline phase, an amorphous material as a material consisting of an amorphous phase, and a composite material as a material consisting of a crystalline phase and an amorphous material. A material contains a crystalline phase when the diffraction spectrum obtained by a typical X-ray diffraction method contains a sharp diffraction peak that identifies the type of crystalline phase. In this case, the crystalline phase may be a single crystal structure or a polycrystalline structure. The polycrystalline structure may be a structure containing microcrystals with small crystal sizes, or may have a so-called nanocrystalline structure with nanoscale crystal sizes. Furthermore, a material contains an amorphous phase when the diffraction spectrum obtained by a typical X-ray diffraction method contains a broad peak indicating an amorphous phase. A material also contains an amorphous phase when the DSC curve obtained by differential thermal analysis contains a peak indicating crystallization, i.e., heat generation associated with a phase change from an amorphous phase to a crystalline phase.

[0051] When the magnetic powder 31 includes a metallic portion, the material of the metallic portion is not limited. Specific examples of crystalline materials include Fe—Si—Cr alloys, Fe—Ni alloys, Fe—Co alloys, Fe—V alloys, Fe—Al alloys, Fe—Si alloys, Fe—Si—Al alloys, pure iron, and ferrite. Carbonyl iron powder is preferred as pure iron powder. Specific examples of amorphous materials include Fe—Si—B alloys, Fe—P—C alloys, and Co—Fe—Si—B alloys. Specific examples of composite materials include Fe—Zr alloys, Fe—Zr—B alloys, Fe—Si—B—Nb—Cu alloys, and Fe—Si—B—P—Cu alloys. When the magnetic powder 31 is a metal powder containing Fe, the synergistic effect of improving magnetic properties is particularly significant.

[0052] When the magnetic powder 31 includes a metallic portion, the chemical composition of the metallic portion is not limited. For example, an Fe—Si—Cr alloy may be composed of 1.0 to 10.0 mass% Si, 1.0 to 10.0 mass% Cr, and the balance consisting of Fe and impurities. Also, for example, an Fe—Ni alloy may be composed of 1.0 to 99.0 mass% Ni, and the balance consisting of Fe and impurities. Furthermore, for example, an Fe—P—C alloy may be composed of 1.0 to 13.0 atomic% P, 1.0 to 13.0 atomic% C, and the balance consisting of Fe and impurities. This Fe—P—C alloy may contain one or more optional elements selected from the group consisting of Ni, Sn, Cr, B, and Si. In this case, for example, the amount of Ni may be 0 to 10.0 atomic %, the amount of Sn may be 0 to 3.0 atomic %, the amount of Cr may be 0 to 6.0 atomic %, the amount of B may be 0 to 9.0 atomic %, and the amount of Si may be 0 to 7.0 atomic %. The amount of Fe is preferably 65 atomic % or more. Furthermore, for example, the Fe-Si-B-Nb-Cu alloy may be composed of 1.0 to 16.0 atomic % Si, 1.0 to 15.0 atomic % B, 0.50 to 5.0 atomic % Nb, 0.50 to 5.0 atomic % Cu, and the balance consisting of Fe and impurities. In this case, the amount of Fe is preferably 65 atomic % or more.

[0053] There are no limitations on the shape of the magnetic powder 31. The magnetic powder 31 may be spherical, elliptical, scaly, or irregularly shaped. There are also no limitations on the manufacturing method for obtaining these shapes.

[0054] The particle size distribution of the magnetic powder 31 is not limited. The particle size distribution of the magnetic powder 31 can be obtained, for example, by analyzing an image (secondary electron image) obtained by capturing an image of a cut surface of the main body 30 with a scanning electron microscope. For example, the average equivalent circle diameter of the magnetic powder 31 may be 0.50 to 50.0 μm. The distribution of equivalent circle diameters may include multiple peaks.

[0055] The magnetic powder 31 may be subjected to a surface insulating treatment. When the magnetic powder 31 is subjected to a surface insulating treatment, the insulation resistance of the main body 30 is improved. The type of surface insulating treatment to be applied to the magnetic powder 31 is not limited. Examples include phosphate treatment, phosphate salt treatment, and oxidation treatment. The magnetic powder 31 may have an insulating coating on the surface of the magnetic particles. This insulating coating may contain at least one element selected from the group consisting of Si, P, and B, and O (oxygen).

[0056] 4 to 6, the magnetic powder 31 is made of a mixture of powder material having a circle-equivalent diameter of submicrons to several μm and powder material having an average circle-equivalent diameter of approximately 5 to 10 μm. When the magnetic powder 31 is made of a mixture of materials like this, the distribution of circle-equivalent diameters will have multiple peaks. In this case, multiple powder materials having relatively small diameter peaks can exist in the gaps between adjacent powder materials having relatively large diameter peaks, making it possible to increase the filling rate of the magnetic powder 31 in the main body 30.

[0057] 7 is an explanatory diagram of the structure of the region surrounded by the thick dashed line in Fig. 2, similar to Fig. 3, but is a diagram for explaining the structure of the main body in more detail. As shown in Fig. 7, in one example, the main body 30 included in the coil device 100 according to this embodiment has, in addition to magnetic powder 31 and binder 32, pore portions 33 in which no solid content exists in the main body 30 and an impregnation coating resin 34.

[0058] The composition of the binder 32 is not limited as long as it can hold the magnetic powder 31. It may be composed of an inorganic material, such as water glass, or an organic material. Typical examples of organic materials are resin materials or substances based on such materials. As resin materials, either thermosetting resins, thermoplastic resins, or both may be used. Specific examples include silicone resins, epoxy resins, phenolic resins, melamine resins, urea resins, acrylic resins, and olefin resins. The organic component may contain a substance formed by subjecting the above-mentioned resin materials to heat treatment. Such substances include thermally altered products and thermal decomposition residues of the resin material, and are referred to herein as "thermally altered products of resins, etc." The composition of thermally altered products of resins, etc., can be adjusted depending on the composition of the resin material to be heat-treated, the processing conditions, and other factors. The binder 32 may be composed of one type of material or multiple types of materials.

[0059] The main body 30 may contain other solid components in addition to the magnetic powder 31 and binder 32. Examples of other components include a coupling agent, such as a silane coupling agent, for improving adhesion between the magnetic powder 31 and the binder 32, the lubricating component described above, and a powder different from the magnetic powder 31.

[0060] In the example shown in Figure 7, the binder 32 contains a thermally denatured resin, etc., and includes pore portions 33 formed in the main body portion 30 due to the shrinkage or thermal decomposition of the resin material when the thermally denatured resin, etc. is generated, and further, an impregnating coating resin 34 is arranged so as to fill a portion of the pore portions 33.

[0061] 8 to 10 are diagrams illustrating the manufacturing process of the main body having the structure shown in FIG. 7, with FIG. 8 showing the state after the molding process, FIG. 9 showing the state after the heating process, and FIG. 10 showing the state after the impregnation coating process.

[0062] First, as shown in FIG. 8 , a magnetic powder-dispersed resin composition, which is a mixed material containing a binder precursor 321 containing a resin and magnetic powder 31, is molded to form a green compact 301 having the general shape of the main body 30. Any molding method may be used, and compaction molding, which will be described later, may be employed. In this case, the green compact 301 is made of a green compact, and the main body 30 has a portion made of the green compact. Depending on the pressure applied during molding, the green compact 301 may include pores 33. To facilitate molding, the mixture to be molded may contain a lubricating component such as a fatty acid-based substance such as a stearic acid ester, or may contain a powder different from the magnetic powder 31.

[0063] Next, the molded body 301 is subjected to a heat treatment to generate a thermally altered product of the resin contained in the binder precursor 321, thereby forming the binder 32. The conditions for the heat treatment are arbitrary as long as the desired substance (thermally altered product of the resin, etc.) is generated, and are set appropriately depending on the type of resin, etc. The binder 32 generated by the heat treatment contains a thermally altered product of the resin, and therefore, due to the shrinkage and decomposition of the resin contained in the binder precursor 321, the volume of the pore portion 33 in the heat-treated product 302 increases compared to the molded body 301, as shown in FIG.

[0064] Next, an impregnation coating process is performed on the product 302. In the impregnation coating process, a resin-based material that provides the impregnation coating resin 34 is supplied to the product 302 by a method such as application, and the resin-based material is impregnated from the surface of the product 302 so as to fill at least a portion of the pore portions 33. Thereafter, by performing heating or the like as necessary, a main body 30 is obtained that includes the impregnation coating resin 34 arranged so as to fill at least a portion of the pore portions 33, as shown in FIG.

[0065] The main body 30 thus obtained has superior mechanical strength to the product 302 because the impregnation coating resin 34 is provided near the surface, while having a smaller surface roughness than the product 302. Even if the main body 30 has been subjected to a process equivalent to surface smoothing, the coil component 100 according to this embodiment can increase the surface roughness of the surfaces on which the coated electrodes 401, 451 are applied by the interposition layer 50. When the surface roughness is increased by performing a removal process on the main body 30 as in the prior art, the impregnation coating resin 34 provided to increase the mechanical strength is removed, even if only partially, by the removal process. Therefore, the coil component 100 according to this embodiment has a main body 30 with higher mechanical strength and superior impact resistance than coil components according to the prior art.

[0066] The method for manufacturing the intervening layer 50 is not limited. Any method may be used as long as it can deposit the powder-containing resin on the main body 30. A liquid resin composition containing the powder 51 may be applied to the main body 30. Alternatively, the intervening layer 50 may be formed by spray coating, in which a powder-dispersed resin composition, which is a mixed material containing the powder 51 and a powdered resin material that provides the matrix material 52, is sprayed onto the main body 30 and the resin material is melted and cured by heating, thereby forming the matrix material 52 on the main body 30 while retaining the powder 51. The resin material used in spray coating is preferably solid at room temperature and melts and then hardens by heating. From this perspective, a thermosetting resin such as a phenolic resin, a thermosetting acrylic resin, or an epoxy resin is preferred.

[0067] If the shape of the main body 30 is small (a specific example of such a shape is a rectangular parallelepiped with a bottom surface 30A of approximately 3 mm x 3 mm and a height of 2 mm or less), it is preferable to load a large number of main bodies 30 into a barrel, rotate the barrel to move the main bodies 30 inside the barrel, and spray coat the main bodies 30 inside the barrel while heating them.

[0068] In this case, the powder-dispersed resin composition sprayed from the sprayer adheres to the surface of the main body 30 located within the sprayer's spray area as the barrel rotates. Since the main body 30 is constantly moving within the barrel as the barrel rotates, when the main body 30 moves outside the sprayer's spray area, the resin in the powder-dispersed resin composition adhering to the surface melts and hardens, and in this process, some of the powder 51, particularly the large-diameter powder 51, falls off. As a result, an intervening layer 50 is formed on the surface of the main body 30, in which the relatively small-diameter powder 51 is held in a matrix material 52 made of a hardened resin.

[0069] In this state, the main body 30 moves within the barrel while appropriately contacting other main bodies 30. As a result, the powder 51 that is not well retained by the matrix material 52 falls off from the intervening layer 50. Then, when the main body 30 moves again into the spray injection area, the powder-dispersed resin composition adheres to the intervening layer 50 of the main body 30. The series of processes described above, i.e., (1) adhesion of the powder-dispersed resin composition, (2) the resin melting and hardening occurring outside the spray injection area, causing the intervening layer 50 to grow (increase in thickness), and (3) some of the powder 51 falling off from the surface of the intervening layer 50 due to contact with other main bodies 30, are repeated, thereby forming an intervening layer 50 having a predetermined thickness and composition.

[0070] Because the intervening layer 50 is formed by such a process, when the main body 30 has a shape close to a rectangular parallelepiped, the larger the surface area, the more likely it is that the intervening layer 50 will come into contact with other main body parts 30, and so the surface roughness of the intervening layer 50 formed on a surface having a relatively large area may tend to be smaller than the surface roughness of the intervening layer 50 formed on a surface having a relatively small area. The coated electrodes 401, 451 formed on a surface having a relatively small area tend to have a relatively small coated area (apparent area), but as described above, the smaller the surface area of ​​the main body 30, the greater the surface roughness of the intervening layer 50 formed on that surface, and therefore the ratio of the actual area to the apparent area taking into account the unevenness of the intervening layer 50 tends to be large.

[0071] Therefore, the peel strength per unit area (apparent area) of the coated electrodes 401, 451 provided on the intervening layer 50 formed on a surface having a relatively small area tends to be higher than the peel strength per unit area (apparent area) of the coated electrodes 401, 451 provided on the intervening layer 50 formed on a surface having a relatively large area. Because of this tendency, the peel strength of the coated electrodes 401, 451 in the coil component 100 including the intervening layer 50 formed by spray coating is unlikely to decrease even when the coil component 100 is miniaturized.

[0072] The method for manufacturing coil component 100 according to this embodiment includes forming coating electrodes 401, 451 by applying a conductive-material-containing resin composition containing a conductive material so as to cover a portion of intervening layer 50. This allows coating electrodes 401, 451 to be in contact with intervening layer 50, which has a large surface roughness, and the peel strength of coating electrodes 401, 451 can be increased.

[0073] When the intervening layer 50 is formed on the main body 30 by spray coating as described above, the intervening layer 50 is formed over the entire surface of the main body 30. Therefore, the formed intervening layer 50 covers each of the pair of terminal plates (first terminal plate 20, second terminal plate 25) on the main body 30. If the intervening layer 50 is insulating, a portion of the portion of the intervening layer 50 covering the pair of terminal plates (first terminal plate 20, second terminal plate 25) is removed, for example, by laser irradiation, along with the insulating material covering the conductive bands of the pair of terminal plates (first terminal plate 20, second terminal plate 25), to expose the conductive bands. The coated electrodes 401, 451 are provided so as to contact the exposed conductive bands.

[0074] Fig. 11 is an exploded perspective view of a temporary assembly for manufacturing the coil component according to this embodiment. Fig. 12 is a cross-sectional view showing a process for manufacturing a green body using the temporary assembly. In one specific example, the coil component 100 according to this embodiment is manufactured by powder compacting the temporary assembly 300 shown in Fig. 11, and in this case, the main body 30 has a portion made of a powder compact (green body 301).

[0075] The temporary assembly 300 includes a first preform 131 , a second preform 132 , and a conductive member 133 having a wound body 10P sandwiched between the first preform 131 and the second preform 132 .

[0076] The first preform 131 and the second preform 132 are produced by molding a magnetic powder-dispersed resin composition (a mixed material containing magnetic powder 31 and binder precursor 321). The first preform 131 has a hollow portion that is open on the Z1 side in the Z1-Z2 direction so as to accommodate the wound body 10P of the conductive member 133. A portion 131A that forms the bottom of the hollow portion is intended to form the bottom surface 30A of the main body 30, and portions 131B, 131C, 131D, and 131F that form the side walls of the hollow portion are intended to form the portions of the side surfaces 30B, 30C, 30D, and 30F of the main body 30 that face the coating electrodes 401 and 451.

[0077] The second preform 132 is composed of a plate-shaped portion 132A and a portion 132B that protrudes from the surface of the plate-shaped portion 132A on the Z2 side in the Z1-Z2 direction. The plate-shaped portion 132A is for forming the top surface 30E and the portions of the side surfaces 30B, 30C, 30D, and 30F on the Z1 side in the Z1-Z2 direction of the main body 30, and the protruding portion 132B is for forming the portion inside the inner periphery of the coil 10 in the main body 30.

[0078] Conductive member 133 is a member that provides coil 10 having first terminal plate 20 and second terminal plate 25 extending from both ends, and has wound body 10P formed by winding a conductive band in an edgewise coil shape around winding axis O along the Z1-Z2 direction. Unlike coil 10 provided in coil device 100, Fig. 11 shows a state in which the final valley folds at both ends of conductive member 133 have not been made, that is, a state in which the plate surfaces of the portions corresponding to the pair of terminal plates (first terminal plate 20, second terminal plate 25) are arranged so that the direction along winding axis O of wound body 10P (Z1-Z2 direction) is the in-plane direction.

[0079] The conductive member 133 is placed so that the wound body 10P is positioned around the protruding portion 132B of the second preform 132, and the first preform 131 is then placed so that it accommodates the wound body 10P, thereby obtaining the temporary assembly 300.

[0080] In the molding process, first, as shown in Fig. 12, the temporary assembly 300 is placed in a cavity 74 between an upper mold 72 and a lower mold 73 arranged in a mold body 71 of a press 70.

[0081] In this state, upper mold 72 and lower mold 73 are pressed in a direction (the direction of arrow P in FIG. 12 ) in which first preform 131 and second preform 132 approach each other (pressing step). By applying pressure in this manner, temporary assembly 300 is integrated, and compact 301 (see FIG. 8 ) is formed in which coil 10 made of wound body 10P is embedded and a pair of terminal plates (first terminal plate 20, second terminal plate 25) are arranged on the same surface (the surface on the Z2 side in the Z1-Z2 direction) of the member based on first preform 131.

[0082] The molding conditions (pressure, temperature during pressing, pressing time, etc.) of the temporary assembly 300 are set appropriately depending on the composition and shape of the first preform 131 and the second preform 132. When molding at room temperature (unheated), the first preform 131 and the second preform 132 are integrated into the molded body 301 containing the coil 10 by applying pressure of about 0.5 GPa to 2 GPa for several seconds.

[0083] In compact 301, which is a powder molded body produced by powder molding in this manner, the surfaces along the movement direction (Z1-Z2 direction) of upper die 72 and lower die 73, i.e., the surfaces corresponding to two side surfaces 30C and 30D in the X1-X2 direction of main body 30 and two side surfaces 30B and 30F in the Y1-Y2 direction, slide against the inner surface of upper die 72 or lower die 73 and the inner surface of mold body 71. For this reason, these side surfaces of compact 301 are smoother than the other surfaces of compact 301, i.e., the surfaces corresponding to bottom surface 30A of main body 30 (which becomes the mounting surface that faces the board when mounted) and top surface 30E. This tendency is also maintained in the main body 30 made of the molded body 301 or obtained by further performing an impregnation coating process on the molded body 301, and the two side surfaces 30C and 30D in the X1-X2 direction and the two side surfaces 30B and 30F in the Y1-Y2 direction of the main body 30 tend to be smoother than the surfaces corresponding to the bottom surface 30A and the top surface 30E.

[0084] For this reason, if the coated electrodes 401, 451 were provided on the main body 30 without any special treatment (i.e., without the intervening layer 50), there is a concern that the coated electrodes 401, 451 located on the side surfaces 30B, 30F, 30C, and 30D would have lower peel strength than the coated electrodes 401, 451 located on the bottom surface 30A and the top surface 30E. In contrast, in the coil component 100 according to the present embodiment, the intervening layer 50 is provided on the entire surface of the main body 30 in one example. In this case, the peel strength of the coated electrodes 401, 451 from the main body 30 is less dependent on the surface and is more likely to be uniform. The peel strength of the coated electrodes 401, 451 is the strength until the portion most susceptible to peeling peels off. Therefore, while the main body 30 formed by molding as in the above case tends to have a locally smooth surface, providing the intervening layer 50 on the entire surface of the main body 30 can suppress a decrease in the peel strength of the coated electrodes 401, 451.

[0085] The molded body 301 may be used as the main body 30 as it is, but as described above, it may be preferable to carry out the heat treatment step and the impregnation coating treatment step.

[0086] An electronic or electric device according to one embodiment of the present invention is an electronic or electric device including a substrate on which the coil component 100 according to one embodiment of the present invention is mounted, and the coated electrodes 401, 451 of the coil component 100 are electrically connected to terminals provided on the substrate. Because the electronic or electric device according to one embodiment of the present invention includes a substrate on which the coil component 100 according to one embodiment of the present invention is mounted, even if the coil component 100 is miniaturized as the device is miniaturized, the peel strength of the coated electrodes 401, 451 is high, and the coil component 100 has excellent impact resistance. Therefore, the electronic or electric device according to one embodiment of the present invention is less likely to experience defects caused by a decrease in conductivity within the coil component during the manufacturing process or during use.

[0087] The above-described embodiments are provided to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, the elements disclosed in the above embodiments are intended to encompass all design modifications and equivalents within the technical scope of the present invention. For example, while the coil 10 is substantially embedded in the main body 30 in the above-described embodiment, this is not limiting. The main body 30 may have a drum-shaped portion, and the coil 10 may be wound around the drum-shaped side of the main body 30. In this case, the main body 30 also has a portion located within the range of the induced magnetic field generated when current is applied to the coil 10.

[0088] (Example) A coil component 100 according to the example and a comparative coil component according to the comparative example were mounted on a substrate, and a peel test was performed. The coated electrodes 401, 451 of the coil component 100 were made of cured silver paste. The outer dimensions of the coil component 100 were 4.0 mm × 4.0 mm × 1.5 mm (t). The coil component 100 according to the example differed from the structure shown in FIG. 1 in that the first terminal board 20 and the second terminal board 25 were exposed on the surface (bottom surface 30A) of the main body 30. After forming the impregnation coating resin 34 and the intervening layer 50 on the entire outer surface of the main body 30, including the exposed portions of the first terminal board 20 and the second terminal board 25, the portions of the impregnation coating resin 34 and the intervening layer 50 covering the first terminal board 20 and the second terminal board 25 were removed by laser ablation to expose the first terminal board 20 and the second terminal board 25. Then, coated electrodes 401 and 451 were provided so as to cover the exposed portions.

[0089] The comparative coil component according to the comparative example was manufactured by the same manufacturing method as the coil component 100 according to the example, except that the interposition layer 50 was not provided. Therefore, the outer shape of the comparative coil component was the same as the outer shape of the coil component 100.

[0090] The coil component 100 was mounted by soldering with the bottom surface 30A facing the substrate. The mounted substrate was placed on its side and fixed to a universal material testing machine (Instron Model "3365") with the side surface 30B of the mounted coil component 100 facing upward, and a load was applied vertically downward relative to the side surface 30B until the coil component 100 peeled off from the substrate. A similar test was also performed on a comparison coil component.

[0091] The number of test pieces for each of the coil device 100 and the comparative coil device was four, and the measurement items were as follows.

[0092] (1) Peel Strength The average value of the load (unit: N) when peeled was divided by the area of ​​the mounting surface (4.0 mm x 4.0 mm) to determine the average peel strength (unit: MPa).

[0093] (2) Observation of fracture surfaces and measurement of the area of ​​the coated electrodes The fracture surfaces of the coil component 100, the comparative coil component, and the substrate after the fracture test were observed. For the fracture surfaces of the coil component 100 and the comparative coil component, the area (unit: mm 2 ) was obtained from the observed image, and the average value of the obtained area of ​​the coating-type electrodes was divided by the average value of the area of ​​the coating-type electrodes located on the bottom surface 30A before the test to obtain the survival rate (unit: %) of the coating-type electrodes.

[0094] The observation results are shown in Figures 13 and 14, and the measurement results are shown in Table 3 and Figures 15 and 16. Figure 13 shows the observation results after a peel test on the bottom surface of one of the coil components according to the example. Figure 14 shows the observation results after a peel test on the bottom surface of one of the comparison coil components according to the comparative example. Figure 15 shows the measurement results of the peel strength. Figure 16 shows the measurement results of the area of ​​the coated electrode after the test.

[0095]

[0096] As shown in Table 3 and Fig. 15, the average peel strength was higher for coil device 100 according to the example. This difference is due to the fact that the fracture modes of the example and the comparative example are different, as will be explained next.

[0097] As shown in Fig. 13, in the coil component 100 provided with the intervening layer 50, the fracture surface was mainly composed of the surfaces of the coated electrodes 401, 451, which appear white in the drawing. In contrast, as shown in Fig. 14, in the comparison coil component not provided with the intervening layer 50, the fracture surface was mainly composed of the surface of the main body 30, which appears gray in the drawing. From these observations, it was confirmed that the failure mode of the coil component 100 according to the example was dominated by cohesive failure of the coated electrodes 401, 451, whereas the failure mode of the comparison coil component according to the comparative example was dominated by interfacial peeling between the coated electrodes 401, 451 and the main body 30.

[0098] 13 and 14 , the comparison coil component after the peel test had significant exposure of first terminal plate 20 and second terminal plate 25. Since the load in the peel test was applied from side surface 30B where first terminal plate 20 and second terminal plate 25 are located, it is presumed that the interfacial peeling that occurred between coating electrodes 401, 451 and main body 30 of the comparison coil component was strongly affected by the interfaces between coating electrodes 401, 451 and first terminal plate 20 and second terminal plate 25, and peeling also occurred at these interfaces.

[0099] To quantitatively confirm the differences in these fracture modes, the areas (electrode areas) of the coated electrodes 401 and 451 on the bottom surface 30A were measured before and after the peel test. A clear difference in the electrode area after the peel test was confirmed between the Example and the Comparative Example. The survival rate (= average electrode area after the test / average electrode area before the test) was calculated from the average electrode area before and after the peel test. As shown in Table 3, the survival rate of the coated electrodes 401 and 451 on the fracture surface was approximately 60% for the Example, while it was less than 30% for the Comparative Example, meaning that the survival rate for the Example was more than twice that of the Comparative Example.

[0100] 100: Coil component 10: Coil 10P: Wound body 11, 12: Portion 20: First terminal plate 25: Second terminal plate 30: Main body 30A: Bottom surface 30B, 30C, 30D, 30F: Side surface 30E: Top surface 31: Magnetic powder 32: Binder 33: Pore portion 34: Impregnation coating resin 40, 45: External electrode 50: Intervening layer 50A: First surface 50B: Second surface 51: Powder 52: Matrix material 70: Press machine 71: Mold body 72: Upper mold 73: Lower mold 74: Cavity 131: First preform 131A, 131B, 131C, 131D, 131F: Parts of first preform 132: Second preform 132A, 132B: Parts of second preform 133: Conductive member 300: Temporary assembly 301: Compact 302: Product 321: Binder precursor 401, 451: Coating electrode 402, 452: Plated electrode G: Peeling portion O: Winding axis P: Arrow

Claims

1. A coil component comprising: a coil; a main body containing magnetic powder and a binder, the main body having a portion located within the range of an induced magnetic field generated when electricity is passed through the coil; a coated electrode containing a conductive material, electrically connected to the coil and arranged to cover a portion of the main body; and an intermediate layer made of a powder-dispersed resin, located between the main body and the coated electrode, the intermediate layer having a surface roughness facing the coated electrode that is greater than the surface roughness of the surface facing the main body.

2. The coil component according to claim 1, wherein the powder dispersion resin contains a powder and a matrix material, and when the volumetric particle size distribution of the powder is calculated from the equivalent circular diameter of the cross section of the powder located in an observation field by observing a cross section of the intervening layer, the 50% cumulative particle diameter D50 in the volumetric particle size distribution and the average thickness Ti of the intervening layer in the observation field satisfy the following formula (1): Ti / D50≦20 (1) 3. A coil component as described in claim 1, wherein the binder contains a thermally denatured resin or the like, and the main body has an impregnating coating resin near the surface that fills at least a portion of pores formed when the thermally denatured resin or the like is generated.

4. A coil component as described in claim 1, wherein the main body has a portion made of a powder compact having a mounting surface that faces a substrate when mounted and a side surface that intersects with the mounting surface, and the surface roughness of the mounting surface is greater than the surface roughness of the side surface.

5. The coil component according to claim 4, wherein the side surface is composed of a plurality of surfaces, and an area of ​​the mounting surface is larger than any of the areas of the plurality of surfaces.

6. A method for manufacturing a coil component as described in claim 2, comprising the steps of: spraying a powder-dispersed resin composition containing a thermosetting resin that provides the matrix material and the powder onto the main body, and curing the thermosetting resin attached to the main body, thereby forming the intervening layer; and applying a conductive material-containing resin composition that contains the conductive material so as to cover a portion of the intervening layer, thereby forming the coated electrode.

7. A method for manufacturing a coil component as described in claim 6, comprising the steps of: placing a magnetic powder-dispersed resin composition containing the magnetic powder and the coil in a cavity of a mold and compacting the magnetic powder to form a compact; heating the compact to thermally decompose at least a portion of the resin contained in the magnetic powder-dispersed resin composition to form the binder containing a thermal decomposition residue of the resin in the main body and to generate pores; arranging an impregnating coating resin so as to fill at least a portion of the pores; and spraying the powder-dispersed resin composition onto the main body having the impregnating coating resin.

8. An electronic or electrical device comprising a substrate on which the coil component according to claim 1 is mounted, wherein the coated electrode of the coil component is electrically connected to a terminal provided on the substrate.

Images