JP6388426B2 - Coil parts manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a coil component having a structure in which a spiral coil portion is covered with a magnetic body portion.

  A coil component represented by an inductor, a choke coil, a transformer, etc. (commonly called an inductance component) has a structure in which a spiral coil portion is covered with a magnetic body portion. 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 method of manufacturing a coil component that can satisfy a demand for a large current while being a type in which a spiral coil portion is in direct contact with a magnetic body portion.

  In order to achieve the above object, the present invention provides a method of manufacturing a coil component in which a spiral coil portion covered with a magnetic body portion is in direct contact with the magnetic body portion, and magnetic alloy particles are produced in an oxidizing atmosphere. A magnetic alloy particle having a step of forming an oxide film of the magnetic alloy particle on the surface of the magnetic alloy particle by heat treatment, and the oxide film existing on the surface obtained in the step; The group is the main body of the magnetic body part.

  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 the preferred embodiment, since the magnetic body portion 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 body portion, and the component itself caused by the reduction is not caused. A decrease in saturation magnetic flux density can also be avoided.

  In other words, while the coil part is in direct contact with the magnetic part, the saturation flux density of the part itself can be increased by effectively using the saturation flux density of the magnetic alloy material itself, which requires a higher 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.

FIG. 1 is an external perspective view of a laminated type coil component. 2 is an enlarged cross-sectional view taken along line S11-S11 in FIG. FIG. 3 is an exploded view of the component main body shown in FIG. FIG. 4 is a diagram showing the particle size distribution of the particles constituting the magnetic part shown in FIG. FIG. 5 is a schematic diagram showing a particle state according to an image obtained when the magnetic body portion shown in FIG. 2 is observed with a transmission electron microscope. FIG. 6 is a schematic diagram showing a particle state according to an image obtained when a magnetic part before execution of the binder removal process is observed with a transmission electron microscope. FIG. 7 is a schematic diagram showing the particle state according to an image obtained when the magnetic body portion after execution of the binder removal process is observed with a transmission electron microscope.

[Specific structure example of coil parts]
First, a specific structural example applied to a laminated type coil component obtained by the manufacturing method of the present invention 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. The magnetic body 12 is mainly composed of Fe—Cr—Si alloy particles and does not contain a glass component. 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 2 exists on the surface of each Fe—Cr—Si alloy particle 1, and the magnetic part The Fe—Cr—Si alloy particles 1 in 12 are interconnected via an oxide film 2 that serves as an insulating film, and the Fe—Cr—Si alloy particles 1 in the vicinity of the coil portion 13 are oxidized to serve as an insulating film. The coil portion 13 is in close contact with the material 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. The Fe—Cr—Si alloy particles 1 constituting the magnetic body portion 12 do not actually form a perfect sphere, but all the particles are drawn as spheres to express that the particle diameter has a distribution. In addition, although the thickness of the oxide film 2 existing on the surface of each particle actually varies in the range of 0.05 to 0.2 μm, it expresses that the oxide film 2 exists on the particle surface. Therefore, all the thicknesses of the oxide film 2 are 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.

[Specific example of coil part manufacturing method]
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% for Fe-Cr-Si alloy particles, 13 wt% for butyl carbitol (solvent), 2 wt% for polyvinyl butyral (binder), and Fe-Cr- The d50 (median diameter), d10 and d90 of the Si alloy particles are as described above.

  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 1 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, the oxide film 2 of the particles 1 is formed on the surfaces 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 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”. The same coil component.

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.

[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). .

  DESCRIPTION OF SYMBOLS 1 ... Magnetic alloy particle, 2 ... Oxide film, 3 ... Pore, 4 ... Mixture of solvent and binder, 10 ... Coil component, 11 ... Component main body, 12 ... Magnetic body part, 13 ... Coil part, 14, 15 ... External Terminal

Claims (5)

A method of manufacturing a coil component in which a spiral coil portion covered with a magnetic body portion is in direct contact with the magnetic body portion,
Creating a pre-heat treatment tip using magnetic alloy particles that are not oxidized on the surface;
By heat-treating the chip in an oxidizing atmosphere, an oxide film of the magnetic alloy particles is formed on the surface of the magnetic alloy particles, and the magnetic alloy particles are transferred to the coil through the formed oxide film. A step of closely contacting the part,
The said manufacturing method characterized by having.   The manufacturing method according to claim 1, wherein the magnetic part does not contain a glass component.   The method according to claim 1 or 2, wherein the magnetic alloy particles are Fe-Cr-Si alloy particles. The magnetic alloy particles have a d10 / d50 in the range of 0.1 to 0.7 and a d90 / d50 in the range of 1.4 to 5.0 when viewed as a volume-based particle diameter. is there,
The manufacturing method of any one of Claims 1-3 characterized by the above-mentioned. The magnetic alloy particles have a d50 in the range of 3.0 to 20.0 μm when viewed as a volume-based particle diameter.
The manufacturing method of any one of Claims 1-4 characterized by the above-mentioned.

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