JP5980493B2 - Coil parts - Google Patents

Description

  The present invention relates to a coil component having a structure in which a spiral coil portion is covered with a magnetic body portion and other structures.

  Coil parts typified by inductors, choke coils, transformers, etc. (commonly called inductance parts) have a structure in which a spiral coil part is covered with a magnetic part, or an insulating coated conductor is wound around the magnetic part. It has a structure such as Ferrite (meaning ceramics mainly composed of iron oxide) such as Ni—Cu—Zn-based ferrite is generally used as the material for the magnetic part covering the coil part.

  In recent years, this type of coil component has been required to have a large current (meaning a higher rated current), and in order to satisfy this requirement, the material of the magnetic part is changed from conventional ferrite to Fe—Cr—. Switching to a Si alloy has been studied (see Patent Document 1).

  The Fe—Cr—Si alloy has a higher saturation magnetic flux density than that of the conventional ferrite, but the volume resistivity of the material itself is much lower than that of the conventional ferrite. That is, in a coil component of a type in which the spiral coil portion is in direct contact with the magnetic body portion, for example, a coil component such as a laminated type or a powder type, the material of the magnetic body portion is changed from a conventional ferrite to an Fe—Cr—Si alloy. To switch to the volume resistivity of the magnetic body part itself composed of the Fe-Cr-Si alloy particle group close to the volume resistivity of the magnetic body part itself composed of the ferrite particle group, preferably higher than the volume resistivity. Ingenuity is required.

  In short, if high volume resistivity cannot be secured in the magnetic body part itself composed of Fe-Cr-Si alloy particles, the saturation flux density of the component itself cannot be increased by effectively utilizing the saturation flux density of the material itself, and the coil Since the current leaks from the part to the magnetic part and the magnetic field is disturbed, the inductance of the component itself decreases.

  By the way, in Patent Document 1 mentioned above, as a method for producing a magnetic body part in a laminated type coil component, a magnetic body formed by a magnetic paste containing a glass component in addition to a Fe—Cr—Si alloy particle group. A method is disclosed in which a layer and a conductor pattern are laminated and fired in a nitrogen atmosphere (= in a reducing atmosphere), and then the fired product is impregnated with a thermosetting resin.

  However, in this manufacturing method, since the glass component contained in the magnetic paste remains in the magnetic body portion, the volume fraction of Fe—Cr—Si alloy particles is reduced by the glass component existing in the magnetic body portion, and the decrease As a result, the saturation magnetic flux density of the component itself also decreases.

JP 2007-027354 A

  An object of the present invention is to provide a coil component that can satisfy the demand for a large current even when the spiral coil portion is of a type that directly contacts a magnetic body portion.

  In order to achieve the above object, the present invention provides the following coil component. The coil component of this invention has a magnetic body part and a coil part formed in this magnetic body part. The coil part is preferably spiral and preferably in direct contact with the magnetic part. According to one aspect of the present invention, the coil part is covered with the magnetic part, and according to another aspect, the coil part is wound around the magnetic part as a magnetic core. The magnetic body portion is mainly composed of magnetic alloy particle groups. The magnetic body portion may or may not contain a glass component. The magnetic alloy particles have a d50 in the range of 3.0 to 20.0 μm, a d10 / d50 in the range of 0.1 to 0.7, and a d90 when viewed as a volume-based particle diameter. / D50 is in the range of 1.4 to 5.0. Preferably, the magnetic alloy particles are made of a Fe—Cr—M soft magnetic alloy (where M is a metal element that is easier to oxidize than Fe), and more preferably, M is Si. An oxide film exists on the surface of each magnetic alloy particle. The oxide film may be present on a part of the surface of the magnetic alloy or may be present on the entire surface. The oxide film is made of an oxide of magnetic alloy particles. Preferably, the oxide film is made of an oxide of a Fe-Si-M soft magnetic alloy (where M is a metal element that is easier to oxidize than Fe), and the metal element represented by M with respect to the Fe element. Is larger than the magnetic alloy particles.

  Preferably, the magnetic alloy particle group has a coupling portion via an oxide film existing on the surface of the adjacent magnetic alloy particle, and a coupling portion between the magnetic alloy particles in a portion where the oxide film does not exist. . It is preferable that the ratio B / N of the number N of magnetic alloy particles in the cross section of the magnetic alloy particle group and the number B of the bonding portions between the magnetic alloy particles is 0.1 to 0.5. Such a magnetic alloy particle group is preferably formed by forming magnetic alloy particles having no oxide film on at least a part of the particle surface under non-heating conditions, and then performing heat treatment. It is obtained by forming a film and forming a joint portion between adjacent magnetic alloy particles via the oxide film. The magnetic alloy particle group is preferably obtained by forming a plurality of magnetic alloy particles produced by an atomizing method and heat-treating them in an oxidizing atmosphere.

  According to the present invention, there is an oxide film (= insulating film) of the magnetic alloy particles on the surface of each of the magnetic alloy particles constituting the magnetic body portion, and the magnetic alloy particles in the magnetic body portion are the insulating film. Since the magnetic alloy particles in the vicinity of the coil portion are in close contact with the coil portion through the oxide film serving as an insulating film, the magnetic alloy particle group is A high volume resistivity can be secured in the main magnetic body itself. In addition, when the magnetic part does not contain a glass component, the volume fraction of the magnetic alloy particles is not reduced by the glass component existing in the magnetic part, and the saturation magnetic flux density of the component itself due to the reduction is reduced. Reduction can also be avoided.

  In other words, even when the coil part is in direct contact with the magnetic part, the saturation flux density of the magnetic alloy material itself can be effectively utilized to increase the saturation flux density of the part itself, which requires a large current. This is satisfactory, and a phenomenon in which current leaks from the coil portion to the magnetic body portion to disturb the magnetic field can be prevented, so that a reduction in inductance of the component itself can be avoided.

  The above object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

It is an external appearance perspective view of a laminated type coil component. It is an expanded sectional view which follows the S11-S11 line | wire of FIG. FIG. 2 is an exploded view of the component main body shown in FIG. 1. It is a figure which shows the particle size distribution of the particle | grains which comprise the magnetic body part shown in FIG. It is the schematic diagram showing the particle state according to the image obtained when the magnetic body part shown in FIG. 2 was observed with the transmission electron microscope. It is the schematic diagram showing the particle state according to the image obtained when the magnetic body part before execution of a binder removal process was observed with the transmission electron microscope. It is the schematic diagram showing the particle state according to the image obtained when the magnetic body part after execution of a binder removal process was observed with the transmission electron microscope. It is a side view which shows the external appearance of the magnetic body part of winding type coil components. It is the transparent side view which shows a part of coil component of a winding type. It is a longitudinal cross-sectional view which shows the internal structure of the coil component of FIG. It is sectional drawing which represents typically the fine structure of the magnetic body part in one embodiment of this invention.

  The coil component of this invention has a magnetic body part and a coil part formed in this magnetic body part. Examples of such a coil component include a laminated type coil component (a laminated inductor or the like), and a type of coil component in which a conductive wire is wound around a magnetic body portion as a magnetic core. Hereinafter, features of the present invention will be described while explaining typical coil components.

[Specific structure example of laminated type coil components]
First, a specific structural example in which the present invention is applied to a laminated type coil component will be described with reference to FIGS.

  The coil component 10 shown in FIG. 1 has a length L of about 3.2 mm, a width W of about 1.6 mm, a height H of about 0.8 mm, and has a rectangular parallelepiped shape as a whole. The coil component 10 includes a rectangular parallelepiped component main body 11 and a pair of external terminals 14 and 15 provided at both ends in the length direction of the component main body 11. As shown in FIG. 2, the component main body 11 includes a rectangular parallelepiped magnetic body portion 12 and a spiral coil portion 13 covered with the magnetic body portion 12. Is connected to the external terminal 14 and the other end is connected to the external terminal 15.

  As shown in FIG. 3, the magnetic body portion 12 has a structure in which a total of 20 magnetic layers ML1 to ML6 are integrated, has a length of about 3.2 mm, a width of about 1.6 mm, The height is about 0.8 mm. Each of the magnetic layers ML1 to ML6 has a length of about 3.2 mm, a width of about 1.6 mm, and a thickness of about 40 μm. This magnetic part 12 is mainly composed of Fe—Cr—Si alloy particles, and does not contain a glass component in this embodiment. The composition of the Fe—Cr—Si alloy particles is 88 to 96.5 wt% for Fe, 2 to 8 wt% for Cr, and 1.5 to 7 wt% for Si.

As shown in FIG. 4, the Fe—Cr—Si alloy particles constituting the magnetic body portion 12 have a d50 (median diameter) of 10 μm, a d10 of 3 μm, Is 16 μm, d10 / d50 is 0.3, and d90 / d50 is 1.6. Further, as shown in FIG. 5, an oxide film (= insulating film) 2 of the Fe—Cr—Si alloy particles 1 is present on the surface of each of the Fe—Cr—Si alloy particles 1, and the magnetic substance The Fe—Cr—Si alloy particles 1 in the portion 12 are interconnected via an oxide film 2 that acts as an insulating film, and the Fe—Cr—Si alloy particles 1 in the vicinity of the coil portion 13 serve as an insulating film. The coil portion 13 is in close contact with the oxide film 2. The oxide film 2 has been confirmed to contain at least Fe ₃ O ₄ belonging to a magnetic material, and Fe ₂ O ₃ and Cr ₂ O ₃ belonging to a non-magnetic material.

  Incidentally, FIG. 4 shows the particle size distribution measured using a particle size / particle size distribution measuring apparatus (Microtrack manufactured by Nikkiso Co., Ltd.) using a laser diffraction scattering method. FIG. 5 schematically shows a particle state according to an image obtained when the magnetic body portion 12 is observed with a transmission electron microscope. Although the Fe—Cr—Si alloy particles constituting the magnetic body portion 12 do not actually form a perfect sphere, all the particles are drawn as spheres in order to express that the particle diameter has a distribution. In addition, the thickness of the oxide film present on the surface of each particle actually varies in the range of 0.05 to 0.2 μm, but in order to express that the oxide film exists on the particle surface. The entire thickness of the oxide film is drawn equally.

  As shown in FIG. 3, the coil unit 13 includes a total of five coil segments CS1 to CS5 and a total of four relay segments IS1 to IS4 that connect the coil segments CS1 to CS5 in a spiral shape. The number of turns is about 3.5. The coil part 13 is mainly composed of Ag particles. Ag particles have a d50 (median diameter) of 5 μm when viewed as a volume-based particle diameter.

  The four coil segments CS1 to CS4 have a U shape, and the one coil segment CS5 has a strip shape. Each coil segment CS1 to CS5 has a thickness of about 20 μm and a width of about 0.2 mm. It is. The uppermost coil segment CS1 has a continuous L-shaped lead portion LS1 used for connection to the external terminal 14, and the lowermost coil segment CS5 is used for connection to the external terminal 15. An L-shaped lead portion LS2 is continuously provided. Each relay segment IS1 to IS4 has a columnar shape penetrating the magnetic layers ML1 to ML4, and each aperture is about 15 μm.

  As shown in FIGS. 1 and 2, each external terminal 14 and 15 extends to each end face in the length direction of the component main body 11 and four side faces in the vicinity of the end face, and the thickness thereof is about 20 μm. One external terminal 14 is connected to the edge of the lead portion LS1 of the uppermost coil segment CS1, and the other external terminal 15 is connected to the edge of the lead portion LS2 of the lowermost coil segment CS5. The external terminals 14 and 15 are mainly composed of Ag particles. Ag particles have a d50 (median diameter) of 5 μm when viewed as a volume-based particle diameter.

[Example of concrete manufacturing method for laminated type coil components]
Next, an example of a specific method for manufacturing the coil component 10 will be described with reference to FIGS. 3, 5, 6, and 7.

  In producing the coil component 10, using a coating machine (not shown) such as a doctor blade or a die coater, a magnetic paste prepared in advance is applied to the surface of a plastic base film (not shown), This is dried using a dryer (not shown) such as a hot air dryer under conditions of about 80 ° C. and about 5 minutes, corresponding to the magnetic layers ML1 to ML6 (see FIG. 3), and many First to sixth sheets having a size suitable for taking are prepared.

  The composition of the magnetic paste used here is 85 wt% Fe—Cr—Si alloy particles, 13 wt% butyl carbitol (solvent), 2 wt% polyvinyl butyral (binder), and Fe—Cr—Si. The d50 (median diameter), d10, and d90 of the alloy particles are as described above. The Fe—Cr—Si alloy particles used here were confirmed by an electron microscope to confirm that no oxide film was present on at least a part of the particle surface.

  Subsequently, using a punching machine (not shown) such as a punching machine or a laser processing machine, the first sheet corresponding to the magnetic layer ML1 (see FIG. 3) is punched, and the relay segment IS1 (see FIG. 3). Through holes corresponding to the reference) are formed in a predetermined arrangement. Similarly, through holes corresponding to the relay segments IS2 to IS4 (see FIG. 3) are formed in a predetermined arrangement in the second to fourth sheets corresponding to the magnetic layers ML2 to ML4 (see FIG. 3).

  Subsequently, using a printing machine (not shown) such as a screen printing machine or a gravure printing machine, a conductor paste prepared in advance is printed on the surface of the first sheet corresponding to the magnetic layer ML1 (see FIG. 3), This is dried using a dryer (not shown) such as a hot air dryer under conditions of about 80 ° C. and about 5 minutes, and the first printed layer corresponding to the coil segment CS1 (see FIG. 3) is arranged in a predetermined arrangement. Make it. Similarly, the second to fifth printed layers corresponding to the coil segments CS2 to CS5 (see FIG. 3) are formed on the surfaces of the second to fifth sheets corresponding to the magnetic layers ML2 to ML5 (see FIG. 3). In a predetermined arrangement.

  The composition of the conductive paste used here is 85 wt% for Ag particles, 13 wt% for butyl carbitol (solvent), 2 wt% for polyvinyl butyral (binder), and d50 (median diameter) of Ag particles is first. As described in.

  The through holes of a predetermined arrangement formed in each of the first to fourth sheets corresponding to the magnetic layers ML1 to ML4 (see FIG. 3) are positioned so as to overlap the end portions of the first to fourth printing layers of the predetermined arrangement. Therefore, when printing the first to fourth printing layers, a part of the conductor paste is filled in each through hole, and the first to fourth filling portions corresponding to the relay segments IS1 to IS4 (see FIG. 3). Is formed.

  Subsequently, using a suction conveyance machine and a press machine (both not shown), only the first to fourth sheets (corresponding to the magnetic layers ML1 to ML4) provided with the printing layer and the filling portion and the printing layer are provided. The fifth sheet (corresponding to the magnetic layer ML5) provided and the sixth sheet (corresponding to the magnetic layer ML6) not provided with the printing layer and the filling portion are stacked in the order shown in FIG. To produce a laminate.

  Subsequently, using a cutting machine (not shown) such as a dicing machine or a laser processing machine, the laminated body is cut into a component body size, and a chip before heat treatment (including a magnetic body portion and a coil portion before heat treatment). Is made.

  Subsequently, using a heat treatment machine (not shown) such as a firing furnace, a large number of pre-heat treatment chips are heat-treated in a batch in an oxidizing atmosphere such as air. This heat treatment includes a binder removal process and an oxide film formation process. The binder removal process is performed under conditions of about 300 ° C. and about 1 hour, and the oxide film formation process is performed under conditions of about 750 ° C. and about 2 hours. The

  In the pre-heat-treatment chip before performing the binder removal process, as shown in FIG. 6, there are many fine gaps between the Fe—Cr—Si alloy particles 1 in the magnetic body part before the heat treatment. However, the fine gap is filled with the mixture 4 of the solvent and the binder, but these disappear in the binder removal process. Therefore, after the binder removal process is completed, as shown in FIG. Change to pore 3. In addition, a large number of fine gaps exist between Ag particles in the coil part before the heat treatment, and the fine gaps are filled with the mixture of the solvent and the binder, but these disappear in the binder removal process.

  In the oxide film formation process subsequent to the binder removal process, as shown in FIG. 5, the Fe—Cr—Si alloy particles in the magnetic body portion before the heat treatment are densely packed to form the magnetic body portion 12 (FIGS. 1 and 2). At the same time, an oxide film 2 of the particles is formed on the surface of each of the Fe—Cr—Si alloy particles 1. Further, the Ag particle group in the coil part before the heat treatment is sintered to produce the coil part 13 (see FIGS. 1 and 2), and thereby the component main body 11 (see FIGS. 1 and 2) is produced. The

  Incidentally, FIG. 6 and FIG. 7 schematically show the particle state according to images obtained when the magnetic body part before and after execution of the binder removal process is observed with a transmission electron microscope. Although the Fe—Cr—Si alloy particles 1 constituting the magnetic body part before the heat treatment are not actually perfect spheres, all the particles are drawn as spheres for matching with FIG.

  Subsequently, using a coating machine (not shown) such as a dip coating machine or a roller coating machine, a conductor paste prepared in advance is applied to both ends in the length direction of the component main body 11, and this is applied to a heat treatment machine such as a firing furnace. (Not shown), a baking process is performed under conditions of about 600 ° C. and about 1 hour, and by the baking process, the disappearance of the solvent and the binder and the sintering of the Ag particles are performed, and the external terminals 14 and 15 (FIG. 1). And FIG. 2).

  The composition of the conductive paste used here is 85 wt% for Ag particles, 13 wt% for butyl carbitol (solvent), 2 wt% for polyvinyl butyral (binder), and d50 (median diameter) of Ag particles is first. As described in.

[effect]
Next, regarding the effects obtained by the coil component 10, the sample No. 4 will be described.

  In the coil component 10, an oxide film (= insulating film) of the Fe—Cr—Si alloy particles exists on the surface of each Fe—Cr—Si alloy particle constituting the magnetic body portion 12. The Fe—Cr—Si alloy particles in the magnetic part 12 are mutually coupled through an oxide film serving as an insulating film, and the Fe—Cr—Si alloy particles near the coil part 13 serve as an insulating film. Since the coil portion 13 is in close contact with the oxide film thus formed, a high volume resistivity can be ensured in the magnetic body portion itself mainly composed of the Fe—Cr—Si alloy particle group. Further, since the magnetic body portion 12 does not contain a glass component, the volume fraction of the Fe—Cr—Si alloy particles is not reduced by the glass component existing in the magnetic body portion 12, and this reduction is the cause. A decrease in the saturation magnetic flux density of the component itself can also be avoided.

  That is, since the coil portion 13 is of a type in which the coil portion 13 is in direct contact with the magnetic body portion 12, the saturation magnetic flux density of the component itself can be increased by effectively utilizing the saturation magnetic flux density of the Fe—Cr—Si alloy material itself. The demand for a large current can be satisfied, and since a phenomenon in which a current leaks from the coil portion 13 to the magnetic body portion 12 and the magnetic field is disturbed can be prevented, a decrease in inductance of the component itself can be avoided.

  This effect is obtained by the sample No. in Table 1 corresponding to the coil component 10. It can be proved from a volume resistivity of 4 and L × Idc1. The volume resistivity (Ω · cm) shown in Table 1 indicates the volume resistivity of the magnetic part 12 itself, and is measured using a commercially available LCR meter. On the other hand, L × Idc1 (μH · A) shown in Table 1 represents the product of the initial inductance (L) and the DC superimposed current (Idc1) when the initial inductance (L) is reduced by 20%. It is measured at a measurement frequency of 100 kHz using a commercially available LCR meter.

  Here, the pass / fail judgment criteria of volume resistivity and L × Idc1 will be described. Based on the fact that Ni-Cu-Zn based ferrite is widely used among the magnetic parts of the conventional coil parts, for comparison, "in place of Fe-Cr-Si alloy particles, volume-based “The point of using Ni—Cu—Zn ferrite particles having a d50 (median diameter) of 10 μm in terms of the particle diameter” and “a firing process under conditions of about 900 ° C. and about 2 hours instead of the oxide film formation process” A coil component (hereinafter referred to as a comparative coil component) having the same structure and manufacturing method as those of the coil component 10 was manufactured except for the point that “is adopted”.

When the volume resistivity and L × Idc1 of the magnetic part of the comparative coil component were measured in the same manner as described above, the volume resistivity was 5.0 × 10 ⁶ Ω · cm, and L × Idc1 was 5.2 μH · A. However, in a conventional coil component using Ni—Cu—Zn ferrite particles, the volume resistivity of the magnetic body portion is set to 1.0 × 10 ⁷ Ω · Taking into account the situation where it is higher than cm, the standard for judging volume resistivity is “1.0 × 10 ⁷ Ω · cm”, and those above this standard value are judged as “good (○)” A value lower than the reference value was judged as “bad” (x). Also, the L × Idc1 pass / fail judgment criterion is set to the measured value of L × Idc1 of the comparison coil part, that is, “5.2 μH · A”, and a value higher than the reference value is judged as “good (◯)”. Those below the reference value were judged as “bad”.

Sample No. As can be seen from the volume resistivity of 4 and L × Idc1, the sample No. 4 has a volume resistivity of 5.2 × 10 ⁸ Ω · cm, which is higher than the volume resistivity determination criteria (1.0 × 10 ⁷ Ω · cm) described above. Applicable sample No. Since L × Idc1 of 4 is 8.3 μH · A, which is higher than the above-mentioned pass / fail judgment criterion (5.2 μH · A) of L × Idc1, the above-mentioned effect is proved by these numerical values.

[Verification of optimal particle size distribution]
Next, Table 1 shows the result of verifying the optimum particle size distribution (d10 / d50 and d90 / d50) of the Fe—Cr—Si alloy particles constituting the magnetic part 12 of the coil component 10 (sample No. 4). Will be explained with reference to.

  In the coil component 10 (sample No. 4), the d50 (median diameter) of the Fe—Cr—Si alloy particles constituting the magnetic body portion 12 when viewed as a volume-based particle diameter is 10 μm, and d10 is 3 μm and d90 of 16 μm were used, but it was confirmed whether the same effect as described above was obtained even when particles having different particle size distributions (d10 / d50 and d90 / d50) were used.

  Sample No. shown in Table 1 1 to 3 and 5 to 10 have the same structure and manufacturing method as the coil component 10 except that "the Fe-Cr-Si alloy particles having a different d10 value from the coil component 10 (sample No. 4) are used". The same coil component. In addition, the sample No. shown in Table 1 was used. 11 to 22 are coil components having the same structure and manufacturing method as those of the coil component 10 except that "the Fe-Cr-Si alloy particles having a d90 value different from that of the coil component 10 (sample No. 4) are used". is there.

Sample No. As can be seen from the volume resistivity of 1 to 10 and L × Idc1, if d10 is 7 μm or less, the volume is higher than the above-described volume resistivity determination criteria (1.0 × 10 ⁷ Ω · cm). Resistivity can be obtained, and if the value of d10 is 1 μm or more, it is possible to obtain L × Idc1 higher than the L × Idc1 quality criterion (5.2 μH · A) described above. That is, if d10 is in the range of 1 to 7.0 μm (d10 / d50 is in the range of 0.1 to 0.7), excellent volume resistivity and L × Idc1 are obtained.

Sample No. As can be seen from the volume resistivity of 11 to 22 and L × Idc1, when d90 is 50 μm or less, the volume is higher than the above-described volume resistivity determination criteria (1.0 × 10 ⁷ Ω · cm). Resistivity can be obtained, and if the value of d90 is 14 μm or more, it is possible to obtain L × Idc1 that is higher than the above-mentioned criteria for determining the quality of L × Idc1 (5.2 μH · A). That is, if d90 is in the range of 14 to 50 μm (d90 / d50 is in the range of 1.4 to 5.0), excellent volume resistivity and L × Idc1 are obtained.

  In short, if d10 / d50 is in the range of 0.1 to 0.7 and d90 / d50 is in the range of 1.4 to 5.0 when viewed as the volume-based particle diameter, the particle size It was confirmed that the same effect as described above was obtained even when Fe—Cr—Si alloy particles having different distributions (d10 / d50 and d90 / d50) were used.

[Verification of optimal median diameter]
Next, the results of verifying the optimum median diameter (d50) of the Fe—Cr—Si alloy particles constituting the magnetic part 12 of the coil component 10 (sample No. 4) will be described with reference to Table 2. .

  In the coil component 10 (sample No. 4), the d50 (median diameter) of the Fe—Cr—Si alloy particles constituting the magnetic body portion 12 when viewed as a volume-based particle diameter is 10 μm, and d10 is 3 μm and d90 of 16 μm were used, but it was confirmed whether the same effect as described above was obtained even when particles having different d50 (median diameter) were used.

  Sample No. shown in Table 2 Nos. 23 to 31 have the same structure and manufacturing method as the coil component 10 except that “a value of d50 (median diameter) is different from that of the coil component 10 (sample No. 4) using Fe—Cr—Si alloy particles”. Same coil parts.

Sample No. As can be seen from the volume resistivity of 23 to 31 and L × Idc1, when d50 is 20 μm or less, the volume is higher than the above-described criterion for determining the volume resistivity (1.0 × 10 ⁷ Ω · cm). Resistivity can be obtained, and if d50 is 3 μm or more, L × Idc1 higher than the above-mentioned quality judgment criterion (5.2 μH · A) of L × Idc1 can be obtained. That is, if d50 (median diameter) is in the range of 3 to 20 μm, excellent volume resistivity and L × Idc1 can be obtained.

  In short, when the d50 (median diameter) when viewed as a volume-based particle diameter is in the range of 3.0 to 20.0 μm, Fe—Cr—Si alloy particles having different d50 (median diameter) are used. However, it was confirmed that the same effect as described above was obtained.

In each coil component, an SEM observation image of 3000 times the cross section of the magnetic alloy particle group was obtained. Table 3 below shows the number N of the magnetic alloy particles 1 in each sample, the number B of the bonding parts between the magnetic alloy particles in the portion where the oxide film does not exist, and the B / N ratio. Details of B and N are as described later.

[Application to other coil parts]
Next, the numerical range described in the [Verification of optimal particle size distribution] column and the [Verification of optimal median diameter] column is different from (1) the coil component 10 (sample No. 4) and the specific manufacturing method. (2) whether it can be applied to the same type of coil component having a specific structure different from that of the coil component 10 (sample No. 4), or (3) the coil component 10 (sample No. 4). It will be described whether (4) it can be applied to a coil component of a different type from the coil component 10 (sample No. 4).

  (1) In the [Specific Example of Coil Parts Production] column, the composition of the magnetic paste is 85 wt% Fe—Cr—Si alloy particles, 13 wt% butyl carbitol (solvent), polyvinyl butyral (binder) ) Is 2 wt%, but the percentage mass of the solvent and binder can be changed without any problem as long as it is within the range that disappears in the binder removal process, and the same coil as the coil component 10 (sample No. 4). Parts can be manufactured. The same applies to the composition of the conductor paste.

  Moreover, although butyl carbitol was shown as a solvent of each paste, as long as it is a solvent which does not react chemically with Fe-Cr-Si alloy particles and Ag particles, ethers other than butyl carbitol as well as alcohols And those belonging to ketones, esters and the like can be used without problems, and the same coil component as the coil component 10 (sample No. 4) can be manufactured by using Pt particles or Pd particles instead of Ag particles.

  Furthermore, although polyvinyl butyral was shown as a binder of each paste, as long as it is a binder that does not chemically react with Fe—Cr—Si alloy particles and Ag particles, cellulose-based resins other than polyvinyl butyral, polyvinyl acetal type Those belonging to resin or acrylic resin can be used without any problem, and the same coil component as the coil component 10 (sample No. 4) can be manufactured.

  Furthermore, even if an appropriate amount of a nonionic surfactant, an anionic surfactant, or the like as a dispersant is added to each paste, no particular problem occurs, and the same coil component as the coil component 10 (sample No. 4). Can be manufactured.

  Furthermore, the conditions of about 300 ° C. and about 1 hr were shown as the binder removal process. However, as long as the solvent and the binder can be eliminated, the same conditions as the coil component 10 (sample No. 4) are set even if other conditions are set. Coil parts can be manufactured.

  Furthermore, although the oxide film formation process showed conditions of about 750 ° C. and about 2 hours, the oxide film of the particles could be formed on the surface of each Fe—Cr—Si alloy particle, and the Fe—Cr—Si alloy As long as the conditions do not change the physical properties of the particles, the same coil component as the coil component 10 (sample No. 4) can be manufactured even if other conditions are set.

  Furthermore, although the conditions of about 600 ° C. and about 1 hr were shown as the baking treatment, the coil component 10 (sample No. 4) can be used even if other conditions are set as long as the conductor paste can be baked without problems. The same coil component can be manufactured.

  In short, the numerical ranges described in the [Verification of optimal particle size distribution] column and the [Verification of optimal median diameter] column are applicable even when the specific manufacturing method is different from that of the coil component 10 (sample No. 4). .

  (2) In the above [Specific structural example of coil component] column, the magnetic part 12 has a length of about 3.2 mm, a width of about 1.6 mm, and a height of about 0.8 mm. The size of the magnetic body portion 12 is basically only related to the reference value of the saturation magnetic flux density of the component itself. Therefore, even if the size of the magnetic body portion 12 is changed, the effects described in the [Effect] column are provided. Equivalent effect is obtained.

  Further, although the coil portion 13 has a winding number of about 3.5, the number of turns of the coil portion 13 is basically only related to the reference value of the inductance of the component itself. Even if the number of turns is changed, an effect equivalent to the effect described in the [Effect] column can be obtained, and even when the dimensions and shapes of the segments CS1 to CS5 and IS1 to IS4 constituting the coil unit 13 are changed. An effect equivalent to the effect described in the [Effect] column can be obtained.

  In short, the numerical ranges described in the [Verification of optimal particle size distribution] column and [Verification of optimal median diameter] column are the same type of coil component having a specific structure different from that of the coil component 10 (sample No. 4). It can also be applied to.

  (3) In the [specific structural example of the coil component] column, Fe—Cr—Si alloy particles are shown as particles constituting the magnetic body portion 12, but the saturation magnetic flux density of the material itself is higher than the conventional ferrite, In addition, if the magnetic alloy particles have an oxide film (= insulating film) formed on the surface by heat treatment in an oxidizing atmosphere, for example, Fe—Si—Al alloy particles or Fe—Ni—Cr alloy particles are substituted. Even when used in the above, an effect equivalent to the effect described in the [Effect] column can be obtained.

  In short, the numerical ranges described in the [Verification of Optimal Particle Size Distribution] column and the [Verification of Optimal Median Diameter] column indicate that magnetic alloy particles different from those of the coil component 10 (sample No. 4) are magnetic parts 12. It can be applied even when used for.

  (4) In the [specific structural example of the coil component] column, the laminated type coil component 10 is shown. However, if the spiral coil portion is a type of coil component in direct contact with the magnetic body portion, for example, pressure Even when the present invention is applied to a powder-type coil component, an effect equivalent to the effect described in the [Effect] column can be obtained. The powder-type coil component mentioned here has a structure in which a spiral coil wire prepared in advance is embedded in a magnetic part made of magnetic powder using a press, and the magnetic part is configured. If the magnetic part after pressing is heat-treated under the same conditions as in the oxide film forming process using Fe—Cr—Si alloy particles in the magnetic powder, the same effect as described in the above [Effect] column is obtained. An effect is obtained.

  In short, the numerical ranges described in the [Verification of optimal particle size distribution] column and the [Verification of optimal median diameter] column can be applied to a coil component of a type different from that of the coil component 10 (sample No. 4). .

[Specific examples of winding type coil components]
Next, a specific example of a wire-wound chip inductor as a coil component will be described.
FIG. 8 is a side view showing the appearance of the magnetic part manufactured here. FIG. 9 is a transparent side view showing a part of an example of the coil component manufactured here. 10 is a longitudinal sectional view showing the internal structure of the coil component shown in FIG. The magnetic body 110 shown in FIG. 8 is used as a magnetic core for winding a coil of a wire-wound chip inductor. The drum-shaped magnetic core 111 is disposed in parallel with a mounting surface of a circuit board or the like, and is disposed at a plate-shaped core portion 111a for winding a coil, and opposite ends of the core portion 111a. A pair of flanges 111b is provided, and the appearance is a drum shape. The end of the coil is electrically connected to the external conductor film 114 formed on the surface of the flange 111b. The size of the core part 111a was 1.0 mm in width, 0.36 mm in height, and 1.4 mm in length. The size of the flange 111b was 1.6 mm in width, 0.6 mm in height, and 0.3 mm in thickness.

  The wire-wound chip inductor 120 as the coil component has the above-described magnetic core 111 and a pair of plate-like magnetic cores 112 (not shown). The magnetic core 111 and the plate-like magnetic core 112 were manufactured as follows.

The same Fe—Cr—Si alloy particles as those used in the production example “No. 4” in the production example of the multilayer inductor described above were used as raw material particles. In addition, it was 0.25 when the aggregate surface of this alloy powder was analyzed by XPS, and Fe _Metal / (Fe _Metal + Fe _Oxide ) described later was calculated. 100 parts by weight of the raw material particles were stirred and mixed with 1.5 parts by weight of an acrylic binder having a thermal decomposition temperature of 400 ° C., and 0.5 parts by weight of Zn stearate was added as a lubricant. Thereafter, it was molded into a predetermined shape at 8 t / cm ² and heat-treated at 750 ° C. for 1 hour in an oxidizing atmosphere having an oxygen concentration of 20.6% to obtain magnetic alloy particle groups. When the characteristics of the obtained magnetic alloy particle group were measured, the magnetic permeability before the heat treatment was 36, but it was 48 after the heat treatment. The specific resistance was 2 × 10 ⁵ Ωcm, and the strength was 7.5 kgf / mm ² . An SEM observation image of 3000 times the cross section of the magnetic alloy particle group was acquired, the number N of the magnetic alloy particles 1 was 42, the number B of the coupling portions between the magnetic alloy particles was 6, and the B / N ratio was It was confirmed to be 0.14. When the composition analysis of the oxide film in the obtained magnetic alloy particle group was performed, 1.5 mol of Cr element was contained with respect to 1 mol of Fe element. This magnetic alloy particle group was used as a magnetic core. The plate-shaped magnetic core 112 connects the flanges 111b and 111b of the magnetic core 111, respectively. The size of the plate-like magnetic core 112 was 2.0 mm in length, 0.5 mm in width, and 0.2 mm in thickness. A pair of external conductor films 114 are formed on the mounting surface of the flange 111b of the magnetic core 111, respectively. In addition, a coil 115 made of an insulation coated conductor is wound around the core portion 111a of the magnetic core 111 to form a winding portion 115a, and both end portions 115b are respectively formed on the external conductor film 114 on the mounting surface of the flange portion 111b. It is thermocompression bonded. The external conductor film 114 includes a baked conductor layer 114a formed on the surface of the magnetic body 110, a Ni plated layer 114b and a Sn plated layer 114c stacked on the baked conductor layer 114a. The plate-like magnetic core 112 described above is bonded to the flanges 111b and 111b of the magnetic core 111 with a resin adhesive. The external conductor film 114 is formed on the surface of the magnetic part 110, and the end of the magnetic core is connected to the external conductor film 114. The external conductor film 114 was formed by baking a paste obtained by adding glass to silver onto the magnetic body 110 at a predetermined temperature. In manufacturing the baked conductor film layer 114a of the outer conductor film 114 on the surface of the magnetic body 110, specifically, the magnetic alloy particles and the glass frit are mounted on the mounting surface of the flange 111b of the magnetic core 111 made of the magnetic body 110. A baking type electrode material paste (in this example, a baking type Ag paste) was applied, and heat treatment was performed in the air to sinter and fix the electrode material directly on the surface of the magnetic body 110. In this way, a wire-wound chip inductor as a coil component was manufactured.

Referring to these examples, a preferred embodiment of the magnetic alloy particle group is derived in the present invention.
FIG. 11 is a cross-sectional view schematically showing the fine structure of the magnetic part according to an example of the present invention. In the present invention, the magnetic alloy particle group 1 is microscopically grasped as an aggregate formed by combining a number of magnetic alloy particles 1 that were originally independent, and each magnetic alloy particle 1 is surrounded by The oxide film 2 is formed over substantially the entire area, and the insulating property of the magnetic alloy particle group 1 is ensured by the oxide film 2. Adjacent magnetic alloy particles 1 constitute a magnetic alloy particle group 1 having a certain shape mainly by bonding through an oxide film 2 around each magnetic alloy particle 1. According to the preferred embodiment, in part, adjacent magnetic alloy particles 1 are bonded to each other between metal portions where no oxide film exists (reference numeral 6). In this specification, the magnetic alloy particle 1 means a particle made of the above-described alloy material, and when it is particularly emphasized that the oxide film 2 portion is not included, a “metal portion” or a “core” Sometimes written. In the conventional magnetic alloy particle group, those in which magnetic particles or a combination of several magnetic particles are dispersed in a matrix of a cured organic resin have been used. In this invention, it is preferable that the matrix which consists of organic resin does not exist substantially.

  Each of the magnetic alloy particles 1 is preferably made of a Fe—Si—M soft magnetic alloy. Here, M is a metal element that is easier to oxidize than Fe, and typically includes Cr (chromium), Al (aluminum), Ti (titanium), and preferably Cr or Al.

  In the Fe-Si-M soft magnetic alloy, the remainder other than Si and metal M is preferably Fe except for inevitable impurities. Examples of metals that may be contained in addition to Fe, Si, and M include Mn (manganese), Co (cobalt), Ni (nickel), and Cu (copper).

  The chemical composition of the alloy constituting each magnetic alloy particle 1 in the magnetic alloy particle group 1 is obtained, for example, by photographing a cross section of the magnetic alloy particle group 1 using a scanning electron microscope (SEM), and using the energy dispersive X It can be calculated by the ZAF method by line analysis (EDS).

  Each magnetic alloy particle 1 constituting the magnetic alloy particle group 1 has an oxide film 2 on a part or all of its periphery (surface). It can also be expressed that the core made of the soft magnetic alloy described above (that is, the magnetic alloy particles 1) and the oxide film 2 formed around the core exist. The oxide film 2 may be formed at the stage of raw material particles before forming the magnetic alloy particle group 1, or at the stage of raw material particles, the oxide film is not present or very little, and an oxide film is formed in the molding process. You may let them. The presence of the oxide film 2 can be recognized as a difference in contrast (brightness) in a photographed image of about 3000 times by a scanning electron microscope (SEM). The presence of the oxide film 2 ensures the insulation of the entire magnetic part.

  The oxide film 2 is an oxide of a magnetic alloy constituting magnetic alloy particles. Preferably, the oxide film 2 is an Fe—Si—M soft magnetic alloy (where M is a metal element that is more easily oxidized than Fe). The molar ratio of the metal element represented by M to the Fe element is larger than that of the magnetic alloy particles. In order to obtain the oxide film 2 having such a structure, the raw material particles for obtaining the magnetic body portion contain as little Fe oxide as possible or as little Fe oxide as possible. In the process of obtaining the particle group 1, the surface portion of the alloy is oxidized by heat treatment or the like. By such treatment, the metal M that is more easily oxidized than Fe is selectively oxidized, and as a result, the molar ratio of the metal M to Fe in the oxide film 2 is the molar ratio of the metal M to Fe in the magnetic alloy particle 1. It becomes relatively larger than the ratio. Since the oxide film 2 contains more metal element represented by M than Fe element, there is an advantage of suppressing excessive oxidation of the alloy particles.

  The method for measuring the chemical composition of the oxide film 2 in the magnetic alloy particle group 1 is as follows. First, the cross section is exposed by breaking the magnetic alloy particle group 1 or the like. Next, a smooth surface is produced by ion milling or the like and photographed with a scanning electron microscope (SEM), and 2 parts of the oxide film are calculated by energy dispersive X-ray analysis (EDS) by the ZAF method.

  The content of the metal M in the oxide film 2 is preferably 1.0 to 5.0 mol, more preferably 1.0 to 2.5 mol, and still more preferably 1. with respect to 1 mol of iron. 0 to 1.7 mol. A high content is preferable in terms of suppressing excessive oxidation, and a low content is preferable in terms of sintering between magnetic alloy particles. In order to increase the content, for example, a method such as heat treatment in a weak oxidizing atmosphere can be mentioned, and conversely, in order to reduce the content, for example, a heat treatment in a strong oxidizing atmosphere, etc. The method is mentioned.

  In the magnetic alloy particle group 1, the coupling portion between the particles is mainly the coupling portion 5 through the oxide film 2. The presence of the bonding portion 5 via the oxide film 2 visually confirms that the oxide film 2 of the adjacent magnetic alloy particles 1 is in the same phase in, for example, an SEM observation image magnified about 3000 times. You can make a clear decision. For example, even if the oxide films 2 included in the adjacent magnetic alloy particles 1 are in contact with each other, a portion where the interface with the adjacent oxide film 2 is visually recognized in an SEM observation image or the like is formed via the oxide film 2. It cannot be said that it is the coupling part 5. Due to the presence of the coupling portion 5 through the oxide film 2, mechanical strength and insulation are improved. The entire magnetic alloy particle group 1 is preferably bonded via the oxide film 2 of the adjacent magnetic alloy particles 1, but if even a part is bonded, the corresponding mechanical strength and insulating properties can be obtained. Improvement can be achieved, and such a configuration is also an embodiment of the present invention. In addition, as will be described later, the magnetic alloy particles 1 also partially bond with each other without using the oxide film 2. Further, there is a partial form in which the adjacent magnetic alloy particles 1 are merely in physical contact or approach without any bonds through the oxide film 2 or between the magnetic alloy particles 1. Also good.

  In order to generate the coupling portion 5 through the oxide film 2, for example, at the predetermined temperature described below in an atmosphere (for example, in the air) in which oxygen is present when the magnetic alloy particle group 1 is manufactured. For example, heat treatment may be added. Preferably, the bonding part 5 is a bond through an oxide film newly generated during the heat treatment after molding. In other words, the portion where the oxide film was not formed at the time of forming before the heat treatment (magnetic alloy portion) is oxidized during the heat treatment to generate a new oxide film, and the newly generated oxide film is It is preferable that a bond is formed via Here, with regard to “forming before heat treatment”, according to the above-mentioned example, for example, a sheet is made from a magnetic paste for the production of a multilayer inductor, and the sheet is laminated and pressure-bonded. For this purpose, the magnetic alloy particles are mixed with a binder and then formed into a predetermined shape. As such magnetic alloy particles used for forming before heat treatment, that is, forming under non-heated conditions, those having no oxide film on at least a part of the particle surface are preferable. It is preferable to perform molding under such non-heated conditions using such particles, followed by heat treatment. Here, “under non-heating conditions” means a temperature at which the magnetic alloy does not substantially cause an oxidation reaction, and examples thereof include 120 ° C. or less. Originally, by such a heat treatment, preferably, an oxide film is newly generated in a portion of the surface of the magnetic alloy particle where the oxide film did not exist, and between adjacent magnetic alloy particles, Bonds are generated through the newly generated oxide film.

  According to the preferred embodiment, in the magnetic alloy particle group 1, not only the coupling portion 5 through the oxide film 2 but also the coupling portion 6 between the magnetic alloy particles 1 exists. Similar to the case of the joint portion 5 through the oxide film 2 described above, for example, in a SEM observation image magnified about 3000 times, a relatively deep concave portion is recognized in the cross-sectional photograph regarding the curve drawn on the particle surface. The magnetic alloy particles 1 can be visually recognized by, for example, visually confirming that the adjacent magnetic alloy particles 1 have a bonding point that does not pass through the oxide film at a place where the surface curves of the two particles are considered to intersect. The presence of the coupling part 6 can be clearly determined. One of the main effects of the preferred embodiment is that the magnetic permeability can be improved by the presence of the coupling portion 6 between the magnetic alloy particles 1.

  In order to generate the coupling portion 6 between the magnetic alloy particles 1, for example, particles having a small oxide film are used as raw material particles, or the temperature and oxygen partial pressure are set later in the heat treatment for manufacturing the magnetic alloy particle group 1. And adjusting the molding density when obtaining the magnetic alloy particle group 1 from the raw material particles. The temperature in the heat treatment is preferably such that the magnetic alloy particles 1 are bonded to each other and an oxide is not easily generated, and a specific preferable temperature range will be described later. The oxygen partial pressure may be, for example, the oxygen partial pressure in the air. The lower the oxygen partial pressure, the less likely the oxide is generated, and as a result, the magnetic alloy particles 1 are more likely to be bonded to each other.

  According to the preferred embodiment of the present invention, in the magnetic alloy particle group 1, most of the joints between the adjacent magnetic alloy particles 1 are the joints 5 through the oxide film 2. There are joints 6 between the particles. The degree to which the coupling parts 6 between the magnetic alloy particles are present can be quantified as follows. The magnetic alloy particle group 1 is cut, and an SEM observation image magnified about 3000 times with respect to the cross section is obtained. The field of view and the like are adjusted so that 30 to 100 magnetic alloy particles 1 can be seen in the SEM observation image. The number N of the magnetic alloy particles 1 in the observed image and the number B of the coupling parts 6 between the magnetic alloy particles 1 are counted. The ratio B / N of these numerical values is used as an evaluation index for the degree of existence of the coupling portion 6 between the magnetic alloy particles. The method of counting N and B will be described with reference to the embodiment shown in FIG. When the image as shown in FIG. 11 is obtained, the number N of the magnetic alloy particles 1 is 8, and the number N of the magnetic alloy particles 1 is 4. Therefore, in this embodiment, the ratio B / N is 0.5. In the present invention, the ratio B / N is preferably 0.1 to 0.5, more preferably 0.1 to 0.35, and still more preferably 0.1 to 0.25. If B / N is large, the magnetic permeability is improved, and conversely, if B / N is small, the insulation resistance is improved. Therefore, the above preferable range is presented in consideration of the compatibility between the magnetic permeability and the insulation resistance.

In order to obtain the magnetic alloy particle group, the raw material particles are, for example, particles manufactured by an atomizing method. As described above, the magnetic alloy particle group 1 includes not only the coupling portion 5 through the oxide film 2 but also the coupling portion 6 between the magnetic alloy particles 1. Therefore, an oxide film may exist in the raw material particles, but it is better not to exist in excess. Particles produced by the atomization method are preferable in that the oxide film is relatively small. The ratio of the alloy core to the oxide film in the raw material particles can be quantified as follows. Analyzing the raw material particles by XPS, paying attention to the peak intensity of Fe, the integrated value Fe _Metal of the peak where Fe exists in the metal state (706.9 eV) and the integrated value of the peak where Fe exists as the oxide state seeking and Fe _Oxide, quantified by calculating the _{Fe Metal / (Fe Metal + Fe} Oxide). Here, in the calculation of Fe _Oxide , a normal distribution centered on the binding energy of three kinds of oxides of Fe ₂ O ₃ (710.9 eV), FeO (709.6 eV) and Fe ₃ O ₄ (710.7 eV). As a superposition, fitting is performed so as to match the measured data. As a result, Fe _Oxide is calculated as the sum of the peak-separated integrated areas. From the viewpoint of increasing the magnetic permeability by facilitating the formation of the joints 6 between the alloys during the heat treatment, the value is preferably 0.2 or more. The upper limit of the value is not particularly limited, and may be 0.6, for example, from the viewpoint of ease of production, and the upper limit is preferably 0.3. Examples of means for increasing the value include a heat treatment in a reducing atmosphere and a chemical treatment such as removal of a surface oxide layer with an acid. Examples of the reduction treatment include holding at 750 to 850 ° C. for 0.5 to 1.5 hours in an atmosphere containing 25 to 35% hydrogen in nitrogen or argon. Examples of the oxidation treatment include holding in air at 400 to 600 ° C. for 0.5 to 1.5 hours.

For the raw material particles as described above, a known method for producing alloy particles may be adopted. For example, PF20-F manufactured by Epson Atmix Co., Ltd., SFR-FeSiAl manufactured by Nippon Atomizing Co., Ltd., etc. are commercially available. What has been used can also be used. It is very likely that the value of the above-mentioned Fe _Metal / (Fe _Metal + Fe _Oxide ) is not taken into consideration for commercially available products, so it is possible to sort the raw material particles or perform pretreatment such as heat treatment and chemical treatment as described above. preferable.

  There is no particular limitation on the method for obtaining the molded body from the raw material particles, and examples of manufacturing the laminated inductor and the winding coil described above can be referred to, and other known means for manufacturing the magnetic alloy particle group can be appropriately incorporated.

  DESCRIPTION OF SYMBOLS 1 ... Magnetic alloy particle, 2 ... Oxide film, 3 ... Pore, 4 ... Mixture of solvent and binder, 5 ... Coupling part through oxide film, 6 ... Coupling part between magnetic alloy particles, 10 ... Coil component , 11 ... component main body, 12 ... magnetic body part, 13 ... coil part, 14, 15 ... external terminal, 110 ... magnetic material, 111, 112 ... magnetic core, 114 ... external conductor film, 115 ... coil

Claims (5)

A magnetic part mainly composed of magnetic alloy particles and a coil part formed on the magnetic part;
There is an oxide film of the magnetic alloy particles on the surface of each of the magnetic alloy particles,
The magnetic alloy particle group has a bonding portion through an oxide film present on the surface of an adjacent magnetic alloy particle and a bonding portion between magnetic alloy particles in a portion where no oxide film exists,
The oxide film is made of an oxide of a Fe-Si-M soft magnetic alloy (where M is a metal element that is easier to oxidize than Fe), and the mole of the metal element represented by M with respect to the Fe element. The ratio is larger than the magnetic alloy particles,
There is no matrix made of organic resin in the magnetic part,
Magnetic alloy particles in which an oxide film does not exist on at least a part of the particle surface are formed under non-heating conditions, and then heat treatment is performed to form an oxide film and between the adjacent magnetic alloy particles. It is obtained by generating a bond through an oxide film,
The magnetic alloy particles have a d50 in the range of 3.0 to 20.0 μm, a d10 / d50 in the range of 0.1 to 0.7 when viewed as a volume-based particle diameter, and d90 / d50 is in the range of 1.4 to 5.0,
Coil parts. The ratio B / N of the number N of the magnetic alloy particles in the cross section of the magnetic alloy particle group and the number B of the bonding portions of the magnetic alloy particles in the portion where the oxide film does not exist is 0.1 to 0.5. The coil component according to claim 1 . The coil component according to claim 1 or 2, wherein the magnetic alloy particles are Fe-Cr-Si alloy particles. The coil component according to claim 3 , wherein the oxide film includes at least Fe ₃ O ₄ belonging to a magnetic material, and Fe ₂ O ₃ and Cr ₂ O ₃ belonging to a non-magnetic material . The coil component according to any one of claims 1 to 4, wherein the magnetic alloy particles are in close contact with the coil portion through the oxide film .

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