Coil components

Abstract

To provide a highly reliable coil component in which the decrease in inductance is suppressed, even when the base body includes a first region and a second region composed of different materials. [Solution] A coil component according to one aspect of the present disclosure comprises a base body including a pair of end faces facing each other, and a coil disposed within the base body, wherein the coil includes at least one coil conductor, and the base body includes a first region and a second region provided at different positions in the direction along the coil axis, the first region includes a ferrite composition consisting of a main component and a secondary component, the main component consisting of 35 to 50 mol% iron oxide in Fe2O3 terms, 1 to 15 mol% copper oxide in CuO terms, 1 to 35 mol% zinc oxide in ZnO terms, and the remainder being nickel oxide, the secondary component includes a lithium compound in an amount of 1.2 parts by mass or less in Li2O terms per 100 parts by mass of the main component, and the second region includes a non-magnetic material.

Description

Technical Field

[0001] This disclosure relates to coil components.

Background Art

[0002] Known coil components include a body and a coil disposed within the body (see, for example, Patent Document 1). The body includes a pair of end faces facing each other. The coil is disposed such that the coil axis extends in a direction in which the pair of end faces face each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors studied a coil component in which the body includes a first region and a second region made of different materials. Then, it became clear that in such a coil component, the sinterability of the second region is low, the inductance of the coil component decreases, and the reliability is low.

[0005] One aspect of this disclosure provides a highly reliable coil component with suppressed reduction in inductance even when the body includes a first region and a second region made of different materials.

Means for Solving the Problems

[0006] A coil component according to one aspect of the present disclosure comprises a base body including a pair of end faces facing each other, and a coil disposed within the base body, the coil including at least one coil conductor, the base body including a first region and a second region provided at different positions in the direction along the coil axis, the first region comprising a ferrite composition consisting of a main component and a minor component, the main component comprising 35 to 50 mol% iron oxide in Fe2O3 terms, 1 to 15 mol% copper oxide in CuO terms, 1 to 35 mol% zinc oxide in ZnO terms, and the remainder being nickel oxide, the minor component comprising a lithium compound in an amount of 1.2 parts by mass or less in Li2O terms per 100 parts by mass of the main component, and the second region comprising a non-magnetic material.

[0007] In one embodiment described above, the content of the lithium compound in the auxiliary component may be 0.005 to 0.50 parts by mass in terms of Li2O, per 100 parts by mass of the main component.

[0008] In one of the above embodiments, the non-magnetic material may include a glass-based material.

[0009] In one of the above embodiments, the non-magnetic material may have a permeability and relative permittivity that are smaller than those of the ferrite composition.

[0010] In the above coil component, the coil is arranged such that the coil axis is aligned in a direction in which the pair of end faces face each other, the element includes a pair of first element portions that each include a corresponding end face from the pair of end faces, and a second element portion located between the pair of first element portions, the second element portion includes the first region and the second region, and the at least one coil conductor may include a coil conductor located in the second element portion.

[0011] The above-mentioned coil component may include the second region in the central portion of the three parts obtained by dividing the above-mentioned second base portion into three equal parts in the direction along the coil axis.

[0012] In one of the above embodiments, each of the three parts may include the first region and the second region.

[0013] In one embodiment described above, the second region may include a plurality of regions located at different positions along the coil axis.

[0014] In one of the above embodiments, the plurality of regions may be arranged symmetrically with respect to the central position of the length of the second element portion in the direction along the coil axis.

[0015] In one of the above embodiments, the plurality of regions may be provided at approximately equal intervals in the direction along the coil axis.

[0016] In one of the above embodiments, the plurality of regions may be arranged so as to be biased toward one of the pair of first elemental parts. [Effects of the Invention]

[0017] According to one aspect of this disclosure, a highly reliable coil component is provided in which the reduction in inductance is suppressed, even when the element includes a first region and a second region composed of different materials. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a perspective view showing a coil component according to the first embodiment. [Figure 2] Figure 2 is an exploded perspective view showing the coil and connection part of a coil component according to the first embodiment. [Figure 3] Figure 3 shows the cross-sectional configuration of a coil component according to the first embodiment. [Figure 4] Figure 4 is a diagram showing the cross-sectional configuration of a coil component according to a first modified example of the first embodiment. [Figure 5] Figure 5 shows the cross-sectional configuration of a coil component according to a second modified example of the first embodiment. [Figure 6]FIG. 6 is a diagram showing a cross-sectional configuration of a coil component according to a third modification of the first embodiment. [Figure 7] FIG. 7 is a diagram showing a cross-sectional configuration of a coil component according to a fourth modification of the first embodiment. [Figure 8] FIG. 8 is a diagram showing a cross-sectional configuration of a coil component according to a fifth modification of the first embodiment. [Figure 9] FIG. 9 is a diagram showing a cross-sectional configuration of a coil component according to a sixth modification of the first embodiment. [Figure 10] FIG. 10 is a diagram showing a cross-sectional configuration of a coil component according to a seventh modification of the first embodiment. [Figure 11] FIG. 11 is a diagram showing a cross-sectional configuration of a coil component according to an eighth modification of the first embodiment. [Figure 12] FIG. 12 is a diagram showing a cross-sectional configuration of a coil component according to a ninth modification of the first embodiment. [Figure 13] FIG. 13 is a perspective view showing a coil component according to the second embodiment. [Figure 14] FIG. 14 is an exploded perspective view showing a coil and a connection part of the coil component according to the second embodiment. [Figure 15] FIG. 15 is a diagram showing a cross-sectional configuration of the coil component according to the second embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals will be used for the same elements or elements having the same function, and redundant descriptions will be omitted.

[0020] [Coil Component] [First Embodiment] Referring to FIGS. 1 to 3, the configuration of a coil component ED1 according to the first embodiment will be described. FIG. 1 is a perspective view showing the coil component according to the present embodiment. FIG. 2 is an exploded perspective view showing the coil and the connection part. FIG. 3 is a diagram showing the cross-sectional configuration of the coil component according to the present embodiment. In FIG. 3, the hatching indicating the cross-section is omitted.

[0021] As shown in Figures 1 to 3, the coil component ED1 comprises a base body 1, a pair of external electrodes 10, and a coil 30. The pair of external electrodes 10 are arranged on the surface of the base body 1. The coil 30 is arranged inside the base body 1 and is electrically connected to the pair of external electrodes 10. The coil 30 is positioned so that its coil axis is aligned in the first direction D1.

[0022] Body 1, for example, has a rectangular parallelepiped shape. In this specification, a rectangular parallelepiped shape includes a rectangular parallelepiped shape in which the corners and edges are chamfered, or a rectangular parallelepiped shape in which the corners and edges are rounded. Body 1 includes a pair of opposing end faces 1a and four side faces 1c connecting the pair of end faces 1a. The surface of Body 1 includes the pair of end faces 1a and the four side faces 1c. Each of the pair of end faces 1a and the four side faces 1c has a rectangular shape. In this specification, a rectangular shape includes, for example, a shape in which each corner is chamfered, or a shape in which each corner is rounded.

[0023] A pair of end faces 1a face each other in a first direction D1. Each pair of end faces 1a has a smaller area than any of the four side faces 1c. Of the four side faces 1c, a pair of side faces 1c face each other in a second direction D2. Another pair of side faces 1c face each other in a third direction D3. The four side faces 1c extend in the first direction D1 so as to connect the pair of end faces 1a. The first direction D1 intersects the second direction D2 and the third direction D3. The second direction D2 intersects, for example, the third direction D3. In this embodiment, the first direction D1, the second direction D2, and the third direction D3 are orthogonal to each other.

[0024] The length of base body 1 in the first direction D1 is, for example, 0.3 to 1.6 mm. The length of base body 1 in the second direction D2 is, for example, 0.1 to 1.0 mm. The length of base body 1 in the third direction D3 is, for example, 0.15 to 0.80 mm. In base body 1, for example, the first direction D1 is the direction of the longer side.

[0025] A pair of external electrodes 10 are positioned at both ends of the base body 1. One external electrode 10 is positioned, for example, on one end face 1a. The other external electrode 10 is positioned, for example, on the other end face 1a. The pair of external electrodes 10 are spaced apart from each other in a first direction D1. Each of the pair of external electrodes 10 includes an electrode portion 10c located on one of the four side surfaces 1c. Each electrode portion 10c is located on one of the four sides 1c. The electrode portion 10c includes a rim 10e. One electrode portion 10c extends along the four sides 1c, for example, from one end face 1a to the rim 10e, toward the other end face 1a. The other electrode portion 10c extends along the four sides 1c, for example, from the other end face 1a to the rim 10e, toward the first end face 1a. The rim 10e is located on the four sides 1c.

[0026] The external electrode 10 includes a conductive material. The conductive material includes, for example, Ag, Pd, Cu, or Al. The conductive material includes, for example, an Ag-Pd alloy, an Ag-Cu alloy, an Ag-Au alloy, or an Ag-Pt alloy. The external electrode 10 includes, for example, a Ni plating film, an Sn plating film, a Cu plating film, or an Au plating film. The external electrode 10 may have a multilayer structure of these plating films, and may include a Ni plating film and an Sn plating film formed on the Ni plating film. The thickness of the portion located on the end face 1a of the external electrode 10 is, for example, 5 to 50 μm.

[0027] The coil 30 includes a plurality of coil conductors 31. The coil 30 may include at least one coil conductor 31. Each coil conductor 31 is arranged such that at least a portion of it overlaps with the others when viewed from a first direction D1. Each coil conductor 31 has a shape, for example, where a portion of the loop is interrupted. Each coil conductor 31 includes a pair of ends. Each coil conductor 31 extends between the pair of ends along an annular trajectory. Among the plurality of coil conductors 31, adjacent coil conductors 31 are connected to each other at the ends of each coil conductor 31 via through-hole conductors 38. When viewed from a first direction D1, the adjacent coil conductors 31 described above overlap at their corresponding ends. The coil component ED1 includes a pair of connectors 33 located at both ends of the coil 30. The pair of connectors 33 electrically connect the coil 30 to a pair of external electrodes 10. In Figure 1, the dashed line schematically shows the outline of the external shape of the coil 30 and the connectors 33.

[0028] As shown in Figure 2, each of the pair of connection sections 33 includes, for example, multiple conductors 33a and one conductor 33b. Among the multiple conductors 33a, adjacent conductors 33a are connected via a through-hole conductor 36. The through-hole conductor 36 electrically connects adjacent conductors 33a, and the conductors 33a are not exposed to the end face 1a, for example. If the conductors 33a are not exposed to the end face 1a, for example, the conductor 33a furthest from the coil 30 is connected to the external electrode 10 via a through-hole conductor 39. The through-hole conductor 39 is located, for example, between the conductor 33a furthest from the coil 30 and the external electrode 10, and electrically connects the conductor 33a furthest from the coil 30 and the external electrode 10. In this embodiment, the conductor 33a furthest from the coil 30 may be exposed to the end face 1a. When the conductor 33a is exposed to the end face 1a, the conductor 33a exposed to the end face 1a is directly connected to the external electrode 10, and each of the pair of connection parts 33 does not include a through-hole conductor 39. The coil component ED1 may also include a configuration in which one of the pair of connection parts 33 includes a through-hole conductor 39, and the other of the pair of connection parts 33 does not include a through-hole conductor 39. In this configuration, one connection part 33 is connected to the external electrode 10 at the through-hole conductor 39, and the other connection part 33 is connected to the external electrode 10 at the conductor 33a exposed to the end face 1a.

[0029] Conductor 33b is located between the coil 30 and the conductor 33a closest to the coil 30 among the multiple conductors 33a. Conductor 33b electrically connects the multiple conductors 33a and the coil 30. Conductor 33b includes, for example, one end connected to conductor 33a and the other end connected to coil 30. One end of conductor 33b is connected to conductor 33a via a through-hole conductor 36. The other end of conductor 33b is connected to coil 30 via a through-hole conductor 37. Among the multiple coil conductors 31 included in coil 30, the coil conductor 31 closest to end face 1a is connected to conductor 33b via a through-hole conductor 37. In Figure 2, some of the multiple conductors 33a and the through-hole conductor 36 are not shown.

[0030] The coil 30 and the connecting portion 33 include a conductive material. The conductive material includes, for example, Ag, Pd, Au, Cu, or Al. The conductive material includes, for example, an Ag-Pd alloy, an Ag-Cu alloy, an Ag-Au alloy, or an Ag-Pt alloy. The coil 30 and the connecting portion 33 include, for example, the same conductive material as the external electrode 10. The coil 30 and the connecting portion 33 may also include a different conductive material than the external electrode 10.

[0031] The base body 1 includes a pair of base body portions 3a and 3b, and a base body portion 3c. The pair of base body portions 3a and 3b each include a corresponding end face 1a of a pair of end faces 1a. In this embodiment, base body portion 3a includes one end face 1a, and base body portion 3b includes the other end face 1a. Base body portion 3c is located between base body portion 3a and base body portion 3b in the first direction D1. In this embodiment, one connection portion 33 is arranged on base body portion 3a. The other connection portion 33 is arranged on base body portion 3b. A coil 30 is arranged on base body portion 3c. In Figure 3, the illustration of the through-hole conductor 36 is omitted. For example, if the base body part 3a includes the first base body part, then the base body part 3c includes the second base body part. For example, if the base body part 3b includes the first base body part, then the base body part 3c includes the second base body part.

[0032] The base body 1 includes, for example, a plurality of insulating layers having electrical insulating properties. In this embodiment, the base body 1 includes a plurality of insulating layers stacked in a first direction D1. The plurality of insulating layers are actually integrated to such an extent that their boundaries are not visible to each other. Each of the plurality of insulating layers, when viewed from the first direction D1, has, for example, a rectangular shape. In this embodiment, the plurality of coil conductors 31 and conductors 33a, 33b are each arranged between adjacent insulating layers among the plurality of insulating layers.

[0033] The boundaries between each elemental part 3a, 3b and elemental part 3c may be defined as follows. For example, a plane that is parallel to one of the pair of end faces 1a that the base portion 3a includes, and that is tangent to the surface facing the one end face 1a, which is included by the coil conductor 31 closest to the one end face 1a, defines the boundary between base portion 3a and base portion 3c. For example, a plane that is parallel to the other end face 1a that the base portion 3b includes, and that is tangent to the surface facing the other end face 1a, which is included by the coil conductor 31 closest to the other end face 1a, defines the boundary between base portion 3b and base portion 3c.

[0034] The base portion 3c includes a plurality of first regions 5a and a plurality of second regions 5b. In this embodiment, the base portion 3c includes, for example, four first regions 5a and four second regions 5b. The four first regions 5a and the four second regions 5b are located at different positions in the first direction D1. The first regions 5a and the second regions 5b are arranged alternately in the first direction D1, for example. The first regions 5a and the second regions 5b may each be an insulating layer. The first regions 5a and the second regions 5b may be in direct contact. An intermediate layer may be formed at the interface between the first regions 5a and the second regions 5b.

[0035] Each of the four second regions 5b is arranged in the first direction D1, from the base body portion 3a to the base body portion 3b, with intervals L1, L2, and L3 between them. That is, the two second regions 5b closest to the base body portion 3a with respect to the central position CL1 are spaced apart by an interval L1. The two central second regions 5b are spaced apart by an interval L2. The two second regions 5b closest to the base body portion 3b with respect to the central position CL1 are spaced apart by an interval L3. In this embodiment, intervals L1, L2, and L3 are approximately the same. The four second regions 5b are provided at approximately equal intervals in the first direction D1. In this specification, "approximately equal intervals" means that in addition to multiple intervals being equal to each other, intervals that include slight differences or manufacturing errors within a predetermined range may be considered approximately equal intervals. For example, if each of the multiple intervals L1, L2, and L3 falls within ±20% of the average value of the multiple intervals L1, L2, and L3, then the multiple second regions 5b are considered to be provided at approximately equal intervals.

[0036] One edge 10e of the electrode portion 10c and the second region 5b are, for example, in contact with each other. In this embodiment, one edge 10e and the second region 5b closest to the base portion 3a are in contact with each other. The second region 5b closest to the base portion 3a is covered by one electrode portion 10c. The other edge 10e and the second region 5b closest to the base portion 3b are in contact with each other. The second region 5b closest to the base portion 3b is covered by the other electrode portion 10c. The two central second regions 5b are, for example, not in contact with the edge 10e. The two central second regions 5b are, for example, exposed from the electrode portion 10c.

[0037] Region 5a contains a ferrite composition comprising a main component and a minor component. The main component consists of 35.0 to 50.0 mol% iron oxide (based on Fe2O3), 1.0 to 15.0 mol% copper oxide (based on CuO), 1.0 to 35.0 mol% zinc oxide (based on ZnO), and the remainder being nickel oxide. The minor component contains a lithium compound in an amount of 1.2 parts by mass or less (based on Li2O) per 100 parts by mass of the main component.

[0038] The content of the main component may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, based on the total amount of the ferrite composition.

[0039] The iron oxide content, calculated as Fe2O3, is preferably 35.0 mol% or more, more preferably 40.0 mol% or more, more preferably 42.0 mol% or more, and even more preferably 45.0 mol% or more, based on the total amount of the main component. The iron oxide content, calculated as Fe2O3, is preferably 50.0 mol% or less, more preferably 49.5 mol% or less, and more preferably 49.0 mol% or less, based on the total amount of the main component. When the iron oxide content is 35.0 mol% or more, the magnetic permeability tends to be high and the decrease in resistivity tends to be suppressed. When the iron oxide content is 50.0 mol% or less, the mechanical strength tends to be high and the temperature characteristics of the magnetic permeability tend to be good.

[0040] The copper oxide content, in CuO equivalent, is 1.0 mol% or more, preferably 6.0 mol% or more, and more preferably 8.0 mol% or more, based on the total amount of the main components. The copper oxide content, in CuO equivalent, is 15.0 mol% or less, preferably 14.0 mol% or less, and more preferably 12.5 mol% or less, based on the total amount of the main components. When the copper oxide content is 1.0 mol% or more, the bending strength tends to increase and the resistivity tends to increase. When the copper oxide content is 15.0 mol% or less, the resistivity tends to increase.

[0041] The zinc oxide content, in terms of ZnO equivalent, is preferably 1.0 mol% or more, more preferably 6.0 mol% or more, more preferably 8.0 mol% or more, and even more preferably 10.0 mol% or more, based on the total amount of the main component. The zinc oxide content, in terms of ZnO equivalent, is preferably 35.0 mol% or less, more preferably 30.0 mol% or less, and more preferably 27.0 mol% or less, based on the total amount of the main component. When the zinc oxide content is 1.0 mol% or more, the magnetic permeability tends to be higher. When the zinc oxide content is 35.0 mol% or less, the decrease in the Curie temperature tends to be suppressed.

[0042] The remainder of the main component is nickel oxide. The nickel oxide content, in NiO equivalent, is, for example, 10.0 to 40.0 mol% relative to the total amount of the main component. When the nickel oxide content is 15.0 mol% or higher, the decrease in the Curie temperature tends to be suppressed. Also, when the nickel oxide content is 40.0 mol% or lower, the real part μ' of the complex permeability tends to increase at high frequencies around 900 MHz.

[0043] Lithium compounds are compounds containing lithium atoms. While lithium compounds are not particularly limited, inorganic compounds are preferred from the viewpoint of ease of handling. Examples of such inorganic compounds include lithium carbonate (Li2CO3), lithium oxide (Li2O), lithium hydroxide (LiOH), lithium acetate (CH3CO2Li), and their hydrates. Among these, lithium carbonate is preferred from the viewpoint of ease of handling. The lithium compound may also be glass containing Li2O. The glass is preferably glass containing Si, Li, and alkaline earth metals (at least one selected from the group consisting of Ba, Sr, and Ca). Lithium compounds may be used individually or in combination of two or more.

[0044] The content of the lithium compound in terms of Li2O is more than 0 parts by mass, preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.015 parts by mass or more, per 100 parts by mass of the main component. The content of the lithium compound in terms of Li2O is 1.2 parts by mass or less, preferably 0.5 parts by mass or less, more preferably 0.2 parts by mass or less, and even more preferably 0.1 parts by mass or less, per 100 parts by mass of the main component. When the content of the lithium compound is 0.005 parts by mass or more and 0.50 parts by mass or less, the sinterability of the second region 5b is further improved. As a result, the coil component ED1 has even higher reliability.

[0045] In addition to the above components, the ferrite composition may further contain minor components such as CoO, SiO2, SnO2, Bi2O3, B2O3, BaO, CaO, SrO, and MgO. The content of these minor components is not particularly limited, but is, for example, about 0.05 to 5.0 parts by mass per 100 parts by mass of the main component.

[0046] In addition to the above components, the ferrite composition may further contain minor components such as MnO, Na2O, K2O, ZrO2, TiO2, and Al2O3. The content of these minor components is not particularly limited, but is, for example, about 0.05 to 1.0 parts by mass per 100 parts by mass of the main component.

[0047] The ferrite composition content in the first region 5a may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass, based on the total amount of the first region 5a.

[0048] The first region 5a may contain oxides of unavoidable impurity elements.

[0049] Examples of unavoidable impurity elements include typical metal elements such as C, S, Cl, As, Se, Br, Te, and I, as well as transition metal elements such as Ga, Ge, Sr, Cd, In, Sb, and Pb, and Sc, V, Cr, Y, Nb, Mo, Pd, Hf, and Ta. The content of oxides of unavoidable impurity elements may be, for example, 0.1 parts by mass or less per 100 parts by mass of the main component.

[0050] The thickness of each of the multiple first regions 5a may be greater than 0 μm, 4 μm or more, or 8 μm or more. The thickness of each of the multiple first regions 5a may be 750 μm or less, 725 μm or less, or 700 μm or less.

[0051] The sum of the thicknesses T1 of the multiple first regions 5a may be greater than 0 μm, 8 μm or more, or 16 μm or more. The sum of the thicknesses T1 of the multiple first regions 5a may be 1500 μm or less, 1450 μm or less, or 1400 μm or less.

[0052] The second region 5b includes non-magnetic materials. Examples of non-magnetic materials include glass-based materials, forsterite materials, willemite materials, alumina materials, cordierite materials, steatite materials, mullite materials, or mixtures of these materials. From the viewpoint of relative permittivity, sinterability, and integration with magnetic materials, the non-magnetic material is preferably a glass-based material, a forsterite material, or a willemite material, and is preferably a mixture of a glass-based material and at least one selected from the group consisting of forsterite materials and willemite materials.

[0053] The content of nonmagnetic material in the second region 5b may be 50% by mass or more, 90% by mass or more, or 99% by mass or more. The content of nonmagnetic material in the second region 5b may be adjusted so that the permeability and relative permittivity of the second region 5b are desired values. For example, the permeability of the second region 5b may be adjusted to be between 1 and 10. For example, the relative permittivity of the second region 5b may be adjusted to be between 3 and 15.

[0054] When the nonmagnetic material is a mixture of a glass-based material and at least one selected from the group consisting of forsterite and willemite materials, the mass ratio of the glass-based material to at least one selected from the group consisting of forsterite and willemite materials (mass of glass-based material: mass of at least one selected from the group consisting of forsterite and willemite materials) is preferably 1.5:98.5 to 23.1:76.9, and more preferably 2.9:97.1 to 13.0:87.0, from the viewpoint of sinterability.

[0055] The second region 5b may contain a lithium compound. The content of the lithium compound in the second region 5b, in terms of Li2O, may have a gradient, increasing closer to the interface between the first region 5a and the second region 5b. The content of the lithium compound in the second region 5b, in terms of Li2O, may be uniform. The content of the lithium compound in terms of Li2O, based on the total amount in the second region 5b, may be 0% by mass or more, 0.001% by mass or more, or 0.01% by mass or more, and may be 1.2% by mass or less, 0.5% by mass or less, 0.2% by mass or less, or 0.1% by mass or less.

[0056] When L1 is the lithium compound content (unit: mass%) in the first region 5a based on the total amount of the first region 5a, and L2 is the lithium compound content (unit: mass%) in the second region 5b based on the total amount of the second region 5b, the ratio of L2 to L1 (L2 / L1) may be 0 or more, 0.01 or more, 0.02 or more, or 0.05 or more, and may be 10.0 or less, 4.0 or less, 2.0 or less, or 1.0 or less.

[0057] The permeability of the ferrite composition included in the first region 5a may be, for example, 2 to 1500. The permeability of the nonmagnetic material included in the second region 5b may be, for example, 1. The relative permittivity of the ferrite composition included in the first region 5a is, for example, 8 to 20. The relative permittivity of the nonmagnetic material included in the second region 5b is, for example, 3 to 15.

[0058] The nonmagnetic material included in the second region 5b may have a permeability and relative permittivity that are smaller than those of the ferrite composition included in the first region 5a. That is, the permeability of the nonmagnetic material included in the second region 5b may be smaller than that of the ferrite composition included in the first region 5a, and the relative permittivity of the nonmagnetic material included in the second region 5b may be smaller than that of the ferrite composition included in the first region 5a. This makes it possible to more reliably produce impedance peaks in the high-frequency range.

[0059] The thickness of each of the multiple second regions 5b may be 3 μm or more, 5 μm or more, or 8 μm or more. The thickness of each of the multiple second regions 5b may be 750 μm or less, 500 μm or less, or 250 μm or less.

[0060] The sum of the thicknesses T2 of the multiple second regions 5b may be 3 μm or more, 5 μm or more, or 8 μm or more. The sum of the thicknesses T2 of the multiple second regions 5b may be 1500 μm or less, 1000 μm or less, or 500 μm or less.

[0061] The ratio (T2 / T1) of the total thickness T2 (unit: μm) of the multiple second regions 5b to the total thickness T1 (unit: μm) of the multiple first regions 5a is preferably 0.002 or more, more preferably 0.01 or more, and even more preferably 0.05 or more, from the viewpoint of further improving the sinterability of the second regions 5b and further improving the reliability of the coil components. The above ratio (T2 / T1) is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.5 or less, from the viewpoint of increasing the proportion of the first regions 5a and improving inductor performance.

[0062] The base body part 3c includes three parts 7a, 7b, and 7c. Parts 7a, 7b, and 7c are arranged in the first direction D1 in the order, for example, 7a, 7b, and 7c. Part 7b is located in the center of parts 7a, 7b, and 7c. Part 7a is located near base body part 3a. Part 7c is located near base body part 3b. Parts 7a, 7b, and 7c divide base body part 3c into three equal parts in the first direction D1, for example.

[0063] In this specification, "three equal parts" may include slight differences or manufacturing tolerances within a predetermined range. For example, if the lengths of each part 7a, 7b, and 7c in the first direction D1 fall within ±20% of the average length of each part 7a, 7b, and 7c in the first direction D1, then each part 7a, 7b, and 7c is considered to be three equal parts of the base part 3c in the first direction D1.

[0064] Each of the portions 7a, 7b, and 7c includes, for example, a first region 5a and a second region 5b. In this embodiment, portion 7a includes one first region 5a and two second regions 5b. Portion 7b includes two first regions 5a and two second regions 5b. Portion 7c includes two first regions 5a and one second region 5b. Adjacent portions 7a and 7b overlap and include one first region 5a and one second region 5b located at the boundary between portions 7a and 7b. Adjacent portions 7b and 7c overlap and include one first region 5a and one second region 5b located at the boundary between portions 7b and 7c. In each of the multiple second regions 5b, three insulating layers containing the second material are stacked continuously with respect to each other without the first region 5a in between.

[0065] Referring to Figure 4, the coil component ED2 according to the first modified example of this embodiment will be described. Figure 4 is a diagram showing the cross-sectional configuration of the coil component according to the first modified example of this embodiment. In Figure 4, the hatching indicating the cross-section and the illustration of the through-hole conductor 36 are omitted. The configuration of coil component ED2 is the same as that of coil component ED1, except for the arrangement of the first region 5a and the second region 5b.

[0066] The base body part 3c includes 24 first regions 5a and 24 second regions 5b. The 24 second regions 5b are located at different positions in the first direction D1. Each of the parts 7a, 7b, and 7c includes eight first regions 5a and eight second regions 5b.

[0067] In the first modified example, the 24 second regions 5b are arranged at approximately equal intervals in the first direction D1. For example, one insulating layer contained in the second region 5b and one insulating layer contained in the first region 5a are alternately stacked. One edge 10e and the three second regions 5b closest to the base portion 3a are in contact with each other. The other edge 10e and the two second regions 5b closest to the base portion 3b are in contact with each other. For example, the second regions 5b other than the five second regions 5b mentioned above are not in contact with the edge 10e and are exposed from the electrode portion 10c.

[0068] Referring to Figure 5, a coil component ED3 according to a second modified example of this embodiment will be described. Figure 5 is a diagram showing the cross-sectional configuration of the coil component according to the second modified example of this embodiment. In Figure 5, the hatching indicating the cross-section and the illustration of the through-hole conductor 36 are omitted. The configuration of coil component ED3 is the same as that of coil component ED1, except for the arrangement of the first region 5a and the second region 5b.

[0069] The base part 3c includes three first regions 5a and three second regions 5b. The three second regions 5b are located at different positions in the first direction D1. Part 7a includes two first regions 5a and two second regions 5b. Part 7b includes two first regions 5a and one second region 5b. Part 7c includes one first region 5a but does not include a second region 5b.

[0070] In the second modification, each of the three second regions 5b is positioned so as to be biased toward the base portion 3a. The three second regions 5b are positioned near the base portion 3a with respect to the central position CL1. Each of the three second regions 5b is arranged with intervals L1 and L2 from each other in the first direction D1, from the base portion 3a toward the base portion 3b. For example, the intervals L1 and L2 are approximately the same. The three second regions 5b are positioned at approximately equal intervals in the first direction D1. In each of the three second regions 5b, three insulating layers containing the second material are stacked continuously from each other without the first region 5a in between.

[0071] One edge 10e and the second region 5b closest to the base body portion 3a are in contact with each other. The other edge 10e and the second region 5b are not in contact with each other. The two second regions 5b closest to the base body portion 3b are not in contact with the edge 10e and are exposed from the electrode portion 10c.

[0072] Referring to Figure 6, a coil component ED4 according to a third modified example of this embodiment will be described. Figure 6 is a diagram showing the cross-sectional configuration of the coil component according to the third modified example of this embodiment. In Figure 6, the hatching indicating the cross-section and the illustration of the through-hole conductor 36 are omitted. The configuration of coil component ED4 is the same as that of coil component ED1, except for the arrangement of the first region 5a and the second region 5b.

[0073] The base part 3c includes five first regions 5a and four second regions 5b. The four second regions 5b are located at different positions in the first direction D1. In the third modified example, the four second regions 5b are located symmetrically with respect to the central position CL1. Of the four second regions 5b, the distance between the two central second regions 5b to the central position CL1 is approximately the same. Of the four second regions 5b, the distance between the two end second regions 5b to the central position CL1 is approximately the same. Of the four second regions 5b, the central position CL1 is located between the two central second regions 5b.

[0074] In the example shown in Figure 6, parts 7a and 7c include one first region 5a but do not include a second region 5b. Part 7b includes five first regions 5a and four second regions 5b. In the third modified example, each of parts 7a and 7c may include a second region 5b. For example, each of parts 7a and 7c may include two first regions 5a and one second region 5b, and part 7b may include three first regions 5a and two second regions 5b. For example, each of parts 7a and 7c may include three first regions 5a and two second regions 5b, and part 7b may include one first region 5a but not include a second region 5b.

[0075] Each of the four second regions 5b is arranged in the first direction D1, from the base body portion 3a to the base body portion 3b, with intervals L1, L2, and L3 between them. In the third modified example, the intervals L1, L2, and L3 are approximately the same. The four second regions 5b are provided at approximately equal intervals in the first direction D1.

[0076] In each of the four second regions 5b, a single insulating layer containing the second material is continuously laminated to each other. The edges 10e and the second regions 5b are not in contact with each other. The four second regions 5b are not in contact with the edges 10e and are exposed from the electrode portion 10c.

[0077] Referring to Figure 7, the coil component ED5 according to the fourth modification of this embodiment will be described. Figure 7 is a diagram showing the cross-sectional configuration of the coil component according to the fourth modification of this embodiment. In Figure 7, the hatching indicating the cross-section and the illustration of the through-hole conductor 36 are omitted. The configuration of coil component ED5 is the same as that of coil component ED1, except for the arrangement of the first region 5a and the second region 5b.

[0078] The base body part 3c includes four first regions 5a and five second regions 5b. The five second regions 5b are located at different positions in the first direction D1. Part 7a includes two first regions 5a and two second regions 5b. Part 7b includes three first regions 5a and two second regions 5b. Part 7c includes two first regions 5a and one second region 5b.

[0079] In the fourth modification, the five second regions 5b are not arranged symmetrically with respect to the central position CL1. The five second regions 5b are arranged in the first direction D1, from the base body portion 3a to the base body portion 3b, with intervals L1, L2, L3, and L4 between them. In the fourth modification, the intervals L1, L2, L3, and L4 are all different from each other. For example, interval L4 is the largest, followed by interval L2. Next is interval L3, and interval L1 is the smallest. In each of the five second regions 5b, three insulating layers containing the second material are stacked continuously on top of each other without any first region 5a in between.

[0080] In the fourth modified example, one edge 10e and the second region 5b closest to the base portion 3a are in contact with each other. The other edge 10e and the second region 5b closest to the base portion 3b are in contact with each other. For example, the three second regions 5b located third to fifth from the base portion 3a are not in contact with the edge 10e and are exposed from the electrode portion 10c.

[0081] Referring to Figure 8, the coil component ED6 according to the fifth modification of this embodiment will be described. Figure 8 is a diagram showing the cross-sectional configuration of the coil component according to the fifth modification of this embodiment. In Figure 8, the hatching indicating the cross-section and the illustration of the through-hole conductor 36 are omitted. The configuration of coil component ED6 is the same as that of coil component ED1, except for the arrangement of the first region 5a and the second region 5b.

[0082] The base part 3c includes five first regions 5a and four second regions 5b. The four second regions 5b are located at different positions in the first direction D1. Part 7a includes two first regions 5a and two second regions 5b. Part 7b includes two first regions 5a and two second regions 5b. Part 7c includes two first regions 5a and one second region 5b.

[0083] In the fifth modification, the four second regions 5b are not arranged symmetrically with respect to the central position CL1. The four second regions 5b are arranged so as to be biased toward the base portion 3a. In each of the four second regions 5b, four insulating layers containing the second material are stacked continuously on each other without the first region 5a in between. Each of the four second regions 5b is arranged in the first direction D1, in the direction from the base portion 3a toward the base portion 3b, with intervals L1, L2, and L3 between them. For example, the intervals L1, L2, and L3 are approximately the same. The four second regions 5b are arranged at approximately equal intervals in the first direction D1.

[0084] One edge 10e and a portion of the second region 5b closest to the base portion 3a are in contact with each other. The portion of the second region 5b closest to the base portion 3a is covered by the electrode portion 10c. One edge 10e and the other portion of the second region 5b closest to the base portion 3a are not in contact with each other. The other portion of the second region 5b closest to the base portion 3a is not covered by one of the electrode portions 10c. The other edge 10e and the second region 5b are not in contact with each other. The three second regions 5b closest to the base portion 3b are not in contact with the edge 10e and are exposed from the electrode portion 10c.

[0085] Referring to Figure 9, the coil component ED7 according to the sixth modified example of this embodiment will be described. Figure 9 is a diagram showing the cross-sectional configuration of the coil component according to the sixth modified example of this embodiment. In Figure 9, the hatching indicating the cross-section and the illustration of the through-hole conductor 36 are omitted. The configuration of coil component ED7 is the same as that of coil component ED1, except for the arrangement of the first region 5a and the second region 5b.

[0086] The base part 3c includes two first regions 5a and two second regions 5b. The two second regions 5b are located at different positions in the first direction D1. Part 7a includes one first region 5a and one second region 5b. Part 7b includes two first regions 5a and one second region 5b. Part 7c includes one first region 5a but does not include a second region 5b.

[0087] In the sixth modification, the two second regions 5b are not arranged symmetrically with respect to the central position CL1. The two second regions 5b are arranged so as to be biased toward the base portion 3a. In each of the two second regions 5b, three insulating layers containing the second material are stacked continuously with respect to each other without the first region 5a in between.

[0088] One edge 10e and the second region 5b, which is close to the base portion 3a, are in contact with each other. The second region 5b, which is close to the base portion 3a, is covered by one electrode portion 10c. The second region 5b, which is close to the base portion 3b, is not in contact with the edge 10e and is exposed from the electrode portion 10c.

[0089] Referring to Figure 10, the coil component ED8 according to the seventh modification of this embodiment will be described. Figure 10 is a diagram showing the cross-sectional configuration of the coil component according to the seventh modification of this embodiment. In Figure 10, the hatching indicating the cross-section and the illustration of the through-hole conductor 36 are omitted. The configuration of coil component ED8 is the same as that of coil component ED1, except for the arrangement of the first region 5a and the second region 5b.

[0090] The base part 3c includes two first regions 5a and two second regions 5b. The two second regions 5b are located at different positions in the first direction D1. Part 7a includes two first regions 5a and two second regions 5b. Parts 7b and 7c include one first region 5a but do not include a second region 5b.

[0091] In the seventh modification, the two second regions 5b are not arranged symmetrically with respect to the central position CL1. The two second regions 5b are arranged so as to be biased toward the base portion 3a. In each of the two second regions 5b, two insulating layers containing the second material are stacked continuously with respect to each other without the first region 5a in between.

[0092] One edge 10e and the second region 5b closest to the base body portion 3a are in contact with each other. One edge 10e and a part of the second region 5b located second from the base body portion 3a are in contact with each other. The second region 5b closest to the base body portion 3a and a part of the second region 5b located second from the base body portion 3a are covered by one electrode portion 10c. One edge 10e and the other part of the second region 5b located second from the base body portion 3a are not in contact with each other. The other part of the second region 5b located second from the base body portion 3a is exposed from one electrode portion 10c. The other edge 10e is not in contact with any of the second regions 5b. The other edge 10e does not cover any of the second regions 5b.

[0093] Referring to Figure 11, the coil component ED9 according to the eighth modification of this embodiment will be described. Figure 11 is a diagram showing the cross-sectional configuration of the coil component according to the eighth modification of this embodiment. In Figure 11, the hatching indicating the cross-section and the illustration of the through-hole conductor 36 are omitted. The configuration of coil component ED9 is the same as that of coil component ED1, except for the arrangement of the first region 5a and the second region 5b.

[0094] The base portion 3c includes two first regions 5a and one second region 5b. Parts 7a and 7c include one first region 5a but do not include a second region 5b. Part 7b includes two first regions 5a and one second region 5b. In the one second region 5b, three insulating layers containing a second material are stacked continuously on each other without any first region 5a in between. The one second region 5b is not in contact with the edge 10e and is exposed from the electrode portion 10c.

[0095] Referring to Figure 12, the coil component ED10 according to the ninth modified example of this embodiment will be described. Figure 12 is a diagram showing the cross-sectional configuration of the coil component according to the ninth modified example of this embodiment. In Figure 12, the hatching indicating the cross-section and the illustration of the through-hole conductor 36 are omitted. The configuration of the coil component ED10 is the same as that of the coil component ED1, except for the size of the base parts 3a, 3b, and 3c, the configuration of the coil 30, and the arrangement of the first region 5a and the second region 5b.

[0096] Each of the base body portions 3a and 3b is longer in the first direction D1 than the base body portions 3a and 3b in this embodiment. The number of coil conductors 31 included in the coil 30 according to the ninth modification is less than the number of coil conductors 31 included in the coil 30 according to this embodiment. The base body portion 3c includes two first regions 5a and one second region 5b. In the ninth modification, portions 7a and 7c include one first region 5a but do not include a second region 5b. Portion 7b includes at least one second region 5b. One second region 5b is not in contact with the edge 10e and is exposed from the electrode portion 10c.

[0097] <Second Embodiment> The configuration of the coil component ED11 according to this embodiment will be described with reference to Figures 13 to 15. Unless otherwise described, the configuration is the same as that of the coil component according to the first embodiment. Figure 13 is a perspective view showing the coil component according to this embodiment. Figure 14 is an exploded perspective view showing the coil and connection. Figure 15 is a diagram showing the cross-sectional configuration of the coil component according to this embodiment. In Figure 15, the hatching indicating the cross-section is omitted.

[0098] In the coil component according to the above embodiment, the coil 30 is arranged such that its coil axis aligns with the first direction D1. On the other hand, in the coil component ED11, the coil 30 is arranged such that its coil axis aligns with the second direction D2. In the coil component according to the above embodiment, the base portion 3a includes one end face 1a, and the base portion 3b includes the other end face 1a. The base portion 3c is located between the base portion 3a and the base portion 3b in the first direction D1. On the other hand, in the coil component ED11, the base portion 3a includes one side surface 1c, and the base portion 3b includes a side surface 1c facing the said side surface 1c. The base portion 3c is located between the base portion 3a and the base portion 3b in the second direction D2. In the coil component according to the above embodiment, portions 7a, 7b, and 7c are arranged in the first direction D1, for example, in the order of portion 7a, portion 7b, and portion 7c. In the coil component ED11, parts 7a, 7b, and 7c are arranged in the second direction D2 in the order, for example, part 7a, part 7b, and part 7c.

[0099] As explained above, in coil components ED1 to ED11, at least one coil conductor 31 is located in the elemental portion 3c, and the magnetic flux generated by the coil conductor 31 reliably passes through the elemental portion 3c along the direction of the coil axis. In other words, the elemental portion 3c affects the characteristics of the coil component, such as impedance and inductance. The elemental portion 3c includes a first region 5a and a second region 5b.

[0100] Since the base portion 3c includes a first region 5a and a second region 5b, which are located at different positions along the coil axis, the magnetic flux generated by the coil conductor 31 reliably passes through the first region 5a and the second region 5b. In other words, the inductance of the coil components ED1 to ED10 can be improved by the first region 5a, while other characteristics can be improved by the second region 5b. For example, the coil components ED1 to ED10 can achieve high impedance in the high frequency band of 700 MHz to 3 GHz.

[0101] Furthermore, in coil components ED1 to ED11, the inclusion of a lithium compound as a minor component in the first region 5a suppresses elemental diffusion at the interface between the first region 5a and the second region 5b, thereby improving the sinterability of the second region 5b. In addition, having 1.2 parts by mass or less of the lithium compound in the first region 5a prevents a decrease in the sinterability of the first region 5a. As a result, coil components ED1 to ED11 exhibit suppressed changes in properties due to thermal shock and other factors, resulting in high reliability. Moreover, having 1.2 parts by mass or less of the lithium compound in the first region 5a suppresses a decrease in the permeability of the first region 5a, thereby suppressing a decrease in inductance.

[0102] In coil components ED1 to ED10, the coil 30 is arranged such that the coil axis is aligned in a direction in which a pair of end faces 1a face each other. The base body 1 includes base body portions 3a and 3b, each containing a corresponding end face from the pair of end faces 1a, and a base body portion 3c located between base body portions 3a and 3b. Base body portion 3c includes a first region 5a and a second region 5b, and at least one coil conductor 31 is located in base body portion 3c. Therefore, coil components ED1 to ED10 have excellent high-frequency characteristics.

[0103] In the coil components ED1-ED7, ED9, ED10, and ED11, the central portion 7b of the three parts 7a, 7b, and 7c obtained by dividing the base portion 3b into three equal parts in the first direction D1 or D2 includes the second region 5b. In coil components ED1-ED7, ED9, ED10, and ED11, the second region 5b, which causes the impedance peak to appear in the high-frequency band, is located in section 7b. Therefore, coil components ED1-ED7, ED9, ED10, and ED11 reliably cause the impedance peak to appear in the high-frequency band.

[0104] In coil components ED1, ED2, ED5, ED6, and ED11, each of the three sections 7a, 7b, and 7c includes the first region 5a and the second region 5b. In coil components ED1, ED2, ED5, ED6, and ED11, a second region 5b, which causes the impedance peak to appear in the high-frequency band, is located in each of the three sections 7a, 7b, and 7c. Therefore, coil components ED1, ED2, ED5, ED6, and ED11 more reliably cause the impedance peak to appear in the high-frequency band.

[0105] In coil components ED1 to ED8, the second region 5b includes multiple second regions 5b located at different positions in the first direction D1. In coil components ED1 to ED8, multiple second regions 5b, which cause impedance peaks to appear in the high-frequency band, are arranged in the base portion 3c. Therefore, coil components ED1 to ED8 more reliably cause impedance peaks to appear in the high-frequency band.

[0106] In the coil component ED11, the second region 5b includes multiple second regions 5b located at different positions in the second direction D2. In the coil component ED11, multiple second regions 5b, which cause impedance peaks to appear in the high-frequency band, are arranged in the base portion 3c. Therefore, the coil component ED11 more reliably causes impedance peaks to appear in the high-frequency band.

[0107] In the coil component ED4, multiple second regions 5b are provided symmetrically with respect to the central position CL1 of the base portion 3c. In the coil component ED4, multiple second regions 5b, which cause impedance peaks to appear in the high-frequency band, are provided symmetrically with respect to the central position CL1. Therefore, the coil component ED4 more reliably causes impedance peaks to appear in the high-frequency band.

[0108] In coil components ED1-ED4 and ED6, multiple second regions 5b are provided at approximately equal intervals in the first direction D1. In coil components ED1-ED4 and ED6, multiple second regions 5b, which cause impedance peaks to appear in the high-frequency band, are provided at approximately equal intervals. Therefore, coil components ED1-ED4 more reliably cause impedance peaks to appear in the high-frequency band.

[0109] In the coil component ED11, multiple second regions 5b are provided at approximately equal intervals in the second direction D2. In the coil component ED11, multiple second regions 5b, which cause impedance peaks to appear in the high-frequency band, are provided at approximately equal intervals. Therefore, the coil component ED11 more reliably causes impedance peaks to appear in the high-frequency band.

[0110] In coil components ED3, ED7, and ED8, multiple second regions 5b are arranged such that they are biased toward one of the pair of base body portions 3a, 3b, towards one of the base body portions 3a. In coil components ED3, ED7, and ED8, even if elements contained in the second region 5b diffuse into the elemental portion 3c, these elements are less likely to diffuse into the elemental portion 3c close to the elemental portion 3b. The first region 5a, located in the elemental portion 3c close to the elemental portion 3b, is less affected by elemental diffusion. Therefore, coil components ED3, ED7, and ED8 reliably suppress the decrease in inductance. In coil components ED4 and ED9, portion 7b includes the first region 5a, while portions 7a and 7c do not include the second region 5b. Even if elements contained in the second region 5b diffuse into the elemental portion 3c, these elements are less likely to diffuse into the elemental portion 3c that is close to the elemental portions 3a and 3b. The elemental portion 3c that is close to the elemental portions 3a and 3b is less affected by elemental diffusion. Therefore, coil components ED4 and ED9 reliably suppress the decrease in inductance.

[0111] In coil components ED1 to ED11, at least one coil conductor 31 includes multiple coil conductors 31. The multiple coil conductors 31 include coil conductors 31 located in the second region 5b. In coil components ED1 to ED11, multiple coil conductors 31 can be arranged in the second region 5b. Therefore, the occurrence of impedance peaks in the high-frequency band is realized by the multiple coil conductors 31. As a result, coil components ED1 to ED11 more reliably produce impedance peaks in the high-frequency band.

[0112] Coil components ED1-ED3 and ED5-ED8 are provided with a pair of external electrodes 10 located at both ends of the base body 1 in the first direction D1 and electrically connected to the coil 30. The base body 1 includes a side surface 1c connecting a pair of end faces 1a. One external electrode 10 includes an electrode portion 10c located on the side surface 1c. The edge 10e of one electrode portion 10c and the second region 5b are in contact with each other. Each of the other external electrodes 10 includes the other electrode portion 10c located on the side surface 1c. The edge 10e of the other electrode portion 10c and the second region 5b are in contact with each other. The coil components ED1-ED3 and ED5-ED8 reduce the stray capacitance formed between the coil 30 and the external electrode 10. Therefore, the coil components ED1-ED3 and ED5-ED8 more reliably produce impedance peaks in the high-frequency range.

[0113] [Manufacturing method for coil components] The following describes a method for manufacturing a coil component according to one embodiment of this disclosure.

[0114] <Preparation process for the composition for forming the first region> Iron oxide, copper oxide, zinc oxide, and nickel oxide are weighed out in predetermined proportions as the main components. A predetermined amount of lithium compound is added to the iron oxide, copper oxide, zinc oxide, and nickel oxide. Each component may contain unavoidable impurities. Next, these weighed materials are mixed in a wet process to obtain a raw material mixture.

[0115] The obtained raw material mixture is dried and then calcined. The calcination temperature may be, for example, 500°C or higher and 900°C or lower. The calcined raw material mixture is then pulverized. This yields a powdered composition for forming the first region. If the calcined raw material mixture forms large lumps, coarse pulverization may be performed before wet pulverization using a ball mill or attritor. Wet pulverization may be performed until the average particle size of the pulverized material is preferably about 0.1 to 1.0 μm.

[0116] The lithium compound may be added to the raw material mixture before calcination as described above, or it may be added during the crushing process after calcination or during the green sheet manufacturing process. When Li2CO3 is used as the lithium compound source, it is preferable to add it during the green sheet manufacturing process because it may dissolve in water. When glass is used as the lithium compound source, it is preferable to add it during the crushing process after calcination in order to finely disperse it.

[0117] <Process for creating the green sheet for forming the first region> A slurry is prepared by mixing the composition for forming the first region with an organic binder such as polyvinyl butyral resin or acrylic resin, an organic solvent such as acetone, ethanol, or toluene, and a plasticizer, and then grinding the mixture. The obtained slurry is then formed into a sheet of a predetermined thickness using a doctor blade method or the like, and then punched out into a predetermined shape to produce a green sheet for forming the first region.

[0118] <Sheet formation process for forming the first region> A conductive paste is applied to the surface of a green sheet using a screen printing method or the like. This results in a coil sheet with a coil conductor pattern formed on the green sheet. Similarly, a through-hole sheet with a through-hole conductor pattern formed on the green sheet is obtained using the same procedure.

[0119] <Preparation process for the composition for forming the second region> A composition for forming the second region is obtained by weighing and mixing non-magnetic materials. When using a mixed powder of borosilicate glass powder and at least one selected from the group consisting of forsterite powder and willemite powder as the non-magnetic material, a glass powder containing boron, silicon, barium, and calcium in predetermined proportions is prepared as the borosilicate glass. In addition, at least one selected from the group consisting of forsterite powder and willemite powder is prepared.

[0120] <Process for creating the green sheet for forming the second region> A slurry is prepared by mixing a composition for forming the second region with an organic binder such as polyvinyl butyral resin or acrylic resin, an organic solvent such as acetone, ethanol, or toluene, and a plasticizer, and then grinding the mixture. The obtained slurry is then formed into a sheet of a predetermined thickness using a doctor blade method or the like, and then punched out into a predetermined shape to produce a green sheet for forming the second region.

[0121] <Sheet formation process for forming the second region> A conductive paste is applied to the surface of a green sheet using a screen printing method or the like. This results in a coil sheet with a coil conductor pattern formed on the green sheet. Similarly, a through-hole sheet with a through-hole conductor pattern formed on the green sheet is obtained using the same procedure.

[0122] <Laminate fabrication process> A laminate is fabricated by stacking coil sheets and through-hole sheets for forming the first and second regions and then heat-pressing them together.

[0123] <Firing Process> The laminate is divided into individual pieces by cutting it into predetermined sizes using a dicer or similar tool. The individual pieces of laminate are then fired. The firing temperature may be, for example, 860°C or higher and 920°C or lower. The firing time may be, for example, 2 hours or more and 8 hours or less. By firing the laminate, the coil conductors and through-hole conductors are electrically connected. This results in a component comprising a base body and a coil. The corners and edges of the component may be rounded, for example, by barrel polishing.

[0124] In the method for manufacturing coil components according to this embodiment, the composition for forming the first region contains a lithium compound. Therefore, during the sintering process, the lithium compound is stably supplied from the first region to the second region. As a result, the sinterability of the second sintering is improved.

[0125] <External electrode formation process> First, a conductive paste containing silver and glass frit is applied to a pair of end faces of the component. Next, each of the resulting coatings is baked to form a base electrode layer on the surface of the pair of end faces of the component.

[0126] Subsequently, a nickel coating and a tin coating are applied to the surface of each underlying electrode layer by electroplating or the like. The components are formed in sequence. This results in a coil component comprising a base body, a pair of external electrodes, and a coil.

[0127] While embodiments and modifications of the coil component of this disclosure, as well as embodiments for manufacturing the same, have been described above, this disclosure is not necessarily limited to the embodiments and modifications described above, and various modifications are possible without departing from the spirit thereof.

[0128] [Summary of this disclosure] The summary of this disclosure is as follows: [1] A body including a pair of opposite end faces, The above-mentioned body comprises a coil arranged within the above-mentioned body, The above coil includes at least one coil conductor, The above-mentioned base body includes a first region and a second region that are located at different positions in the direction along the coil axis, The above first region includes the principal component and the minor component, The main components are iron oxide (35.0-50.0 mol% in Fe2O3 equivalent), copper oxide (1.0-15.0 mol% in CuO equivalent), zinc oxide (1.0-35.0 mol% in ZnO equivalent), and the remainder is nickel oxide. The above-mentioned auxiliary component contains a lithium compound in an amount of 1.2 parts by mass or less (in terms of Li2O) per 100 parts by mass of the above-mentioned main component. The second region mentioned above is a coil component containing non-magnetic materials. [2] The coil component according to [1], wherein the content of the lithium compound in the above-mentioned auxiliary component is 0.005 to 0.50 parts by mass in terms of Li2O per 100 parts by mass of the above-mentioned main component. [3] The coil is arranged such that the coil axis is aligned in a direction in which the pair of end faces face each other, The above-mentioned base body includes a pair of first base body portions, each containing a corresponding end face from the pair of end faces, and a second base body portion located between the pair of first base body portions. The above-mentioned second base portion includes the above-mentioned first region and the above-mentioned second region, The coil component according to [1] or [2], which includes at least one coil conductor disposed in the second body portion. [4] The non-magnetic material is a coil component according to any one of [1] to [3], including a glass-based material. [5] The coil component according to any one of [1] to [4], wherein the non-magnetic material has a permeability and relative permittivity that are smaller than those of the ferrite composition. [6] A coil component according to any of [3] to [5], wherein the central part of the three parts obtained by dividing the above-mentioned second body portion into three equal parts in the direction along the coil axis includes the above-mentioned second region. [7] The coil component according to [6], wherein each of the three parts includes the first region and the second region. [8] The coil component according to any one of [3] to [7], wherein the second region is provided at different locations along the coil axis. [9] The coil component according to [8], wherein the multiple regions are provided symmetrically with respect to the central position of the length of the second body portion in the direction along the coil axis.

[10] The coil component according to [8] or [9], wherein the above-mentioned regions are provided at approximately equal intervals in the direction along the coil axis.

[11] The coil component according to [8], wherein the multiple regions are arranged such that they are biased toward one of the pair of first body parts. [Examples]

[0129] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited to the following examples.

[0130] [Manufacturing of coil components] <Example 1> The coil components shown in Figures 1-3 were obtained through the following process.

[0131] (Preparation step for the composition for forming the first region) Fe2O3, CuO, ZnO, and NiO were weighed as the main components. Each component was weighed so that its content in the first region obtained by sintering was the value shown in Table 1. Li2CO3 was added to the main components. The amount of Li2CO3 added in terms of Li2O per 100 parts by mass of the main components is shown in Table 1. Next, these weighed materials were mixed wet to obtain a raw material mixture. The obtained raw material mixture was dried and then calcined (temperature: 700°C). The calcined raw material mixture was pulverized to obtain a powdered composition for forming the first region.

[0132] (Process for preparing the green sheet for forming the first region) A slurry was prepared by mixing the composition for forming the first region with an organic binder such as an acrylic resin, a mixture of acetone and methyl ethyl ketone, and a plasticizer, and then grinding the mixture. The obtained slurry was then formed into a sheet of a predetermined thickness using a doctor blade method, and then punched out into a predetermined shape to produce a green sheet for forming the first region.

[0133] (Sheet formation process for forming the first region) A conductive paste was applied to the surface of a green sheet using a screen printing method. This resulted in a coil sheet with a coil conductor pattern formed on the green sheet. Similarly, a through-hole sheet with a through-hole conductor pattern formed on the green sheet was obtained using the same procedure.

[0134] (Preparation process for the composition for forming the second region) MgO, ZnO, CuO, and SiO2 were prepared as forsterite and willemite materials. These components were weighed so that after sintering they would be in the formula 2.0(0.66MgO·0.26ZnO·0.08CuO)·SiO2. In addition, B2O3-SiO2-BaO-CaO glass was prepared. The weighed forsterite and willemite materials were wet-mixed in a ball mill for 24 hours to obtain a mixture. The mixture was dried in a dryer and then calcined in a batch furnace at 1000°C to obtain calcined powder. B2O3-SiO2-BaO-CaO glass was added to this calcined powder and wet-mixed in a ball mill for 16 hours. The resulting mixture was dried in a dryer to obtain a composition for forming the second region.

[0135] (Process for preparing the green sheet for forming the second region) A slurry was prepared by mixing a composition for forming the second region with an organic binder such as an acrylic resin, a mixture of acetone and methyl ethyl ketone, and a plasticizer, and then grinding the mixture. The obtained slurry was then formed into a sheet of a predetermined thickness using a doctor blade method, and then punched out into a predetermined shape to produce a green sheet for forming the second region.

[0136] (Sheet formation process for forming the second region) A conductive paste was applied to the surface of a green sheet using a screen printing method. This resulted in a coil sheet with a coil conductor pattern formed on the green sheet. Similarly, a through-hole sheet with a through-hole conductor pattern formed on the green sheet was obtained using the same procedure.

[0137] (Laminate fabrication process) A laminate was fabricated by stacking coil sheets and through-hole sheets for forming the first and second regions and then heat-pressing them together.

[0138] (Firing process) The laminate was cut into individual pieces by a dicing machine to a predetermined size. The individual pieces of laminate were fired (fired at a temperature of 900°C for 2 hours) to obtain a component comprising a base body and a coil.

[0139] (External electrode formation process) A conductive paste (materials: silver and glass frit) was applied to a pair of end faces of the component. Next, each of the resulting coatings was baked to form a base electrode layer on the surface of the pair of end faces of the component.

[0140] Subsequently, nickel and tin coatings were sequentially formed on the surface of each underlying electrode layer by electroplating. This resulted in a coil component comprising a base body, a pair of external electrodes, and a coil. The base body includes a first region containing a ferrite composition and a second region containing a non-magnetic material. The configuration of the coil component is shown below.

[0141] (Composition of coil components) Number of items in the first region 5a: four Number of units in the second region 5b: four Thickness of each of the first regions 5a: Starting from the first region 5a located on one of the pair of end faces, the thicknesses are 71 μm, 71 μm, 71 μm, and 27 μm. The sum of the thicknesses of the four first regions 5a, T1: 240 μm Thickness of each part of the second region 5b: 18 μm The sum of the thicknesses of the four second regions 5b, T2: 72 μm Ratio (T2 / T1):0.3

[0142] <Examples 2-4, Comparative Example 2> A coil component was obtained in the same manner as in Example 1, except that the amount of Li2CO3 added relative to 100 parts by mass of the main component (calculated as Li2O) was changed to the values ​​shown in Table 1.

[0143] <Comparative Example 1> A coil component was obtained in the same manner as in Example 1, except that Li2CO3 was not added to the raw material mixture.

[0144] [Thermal shock test] <Examples 1-4, Comparative Examples 1, 2> For each example and comparative example, the coil components were subjected to 2000 cycles under a predetermined temperature profile within the range of -55 to +125°C. The initial and post-test inductance L of the coil components was measured at a measurement frequency of 10 MHz, and the rate of change in inductance before and after the test was determined. The rate of change in inductance was calculated for 40 coil components in each example and comparative example, and the average value was determined. The results are shown in Table 1.

[0145] [Measurement of magnetic permeability and relative permittivity of ferrite compositions] 100 parts by mass of the powdered first region forming composition were mixed with 10.0 parts by mass of a 6% polyvinyl alcohol aqueous solution as a binder and granulated to form granules. These granules were pressure-molded to obtain toroidal-shaped molded bodies (dimensions = outer diameter 13 mm × inner diameter 6 mm × height 3 mm) and disk-shaped molded bodies (dimensions = outer diameter 12 mm × height 2 mm). These molded bodies were fired in air at 900°C for 2 hours to obtain toroidal core samples and disk samples as sintered bodies. Furthermore, the following characteristics were evaluated for each of the obtained samples. For the toroidal core sample, the magnetic permeability of the ferrite composition was measured using an RF impedance material analyzer (Agilent Technologies E4991A) and a test fixture (Agilent Technologies 16454A). The measurement conditions were a measurement frequency of 1 MHz and a measurement temperature of 25°C. To determine the relative permittivity of the ferrite composition, In-Ga electrodes were applied to both sides of a disk sample, and the capacitance C was measured using an LCR meter (HEWLETT PACKARD 4285A) under the conditions of a measurement temperature of 25°C, a frequency of 1 MHz, and a measurement signal level of 1 Vrms. The relative permittivity was calculated from the obtained capacitance C, the electrode area of ​​the sintered body, and the distance between the electrodes. The results are shown in Table 1.

[0146] [Measurement of permeability and relative permittivity of non-magnetic materials] 100 parts by mass of powdered second region forming composition were mixed with 10.0 parts by mass of a 6% polyvinyl alcohol aqueous solution as a binder and granulated to form granules. These granules were pressure-molded to obtain toroidal-shaped molded bodies (dimensions = outer diameter 13 mm × inner diameter 6 mm × height 3 mm) and disk-shaped molded bodies (dimensions = outer diameter 12 mm × height 2 mm). These molded bodies were fired in air at 900°C for 2 hours to obtain toroidal core samples and disk samples as sintered bodies. Furthermore, the following characteristics were evaluated for each of the obtained samples. For the toroidal core sample, the magnetic permeability of the non-magnetic material was measured using an RF impedance material analyzer (Agilent Technologies E4991A) and a test fixture (Agilent Technologies 16454A). The measurement conditions were a measurement frequency of 1 MHz and a measurement temperature of 25°C. To determine the relative permittivity of non-magnetic materials, In-Ga electrodes were applied to both sides of a disk sample, and the capacitance C was measured using an LCR meter (HEWLETT PACKARD 4285A) under the conditions of a measurement temperature of 25°C, a frequency of 1 MHz, and a measurement signal level of 1 Vrms. The relative permittivity was calculated from the obtained capacitance C, the electrode area of ​​the sintered body, and the distance between electrodes. The magnetic permeability of the non-magnetic material was 1. The relative permittivity of the non-magnetic material was 7.

[0147] [Table 1] [Explanation of symbols]

[0148] 1...element body, 1a...end face, 1c...side surface, 3a...element body part, 3b...element body part, 3c...element body part, 5a...first region, 5b...second region, 7a...part, 7b...part, 7c...part, 10...external electrode, 10c...electrode part, 10e...edge, 30...coil, 31...coil conductor, CL1...center position, ED1...coil part, D1...first direction.

Claims

1. A base body including a pair of opposing end faces, The body comprises a coil disposed within the aforementioned body, The coil includes at least one coil conductor, The aforementioned body includes a first region and a second region that are provided at mutually different positions in the direction along the coil axis, The first region comprises a ferrite composition consisting of a main component and a minor component, The main component is iron oxide Fe ２ O ３ It consists of 35.0 to 50.0 mol% of copper oxide (calculated as CuO), 1.0 to 15.0 mol% of zinc oxide (calculated as ZnO), and the remainder being nickel oxide. The aforementioned auxiliary component is Li in proportion to 100 parts by mass of the main component. ２ It contains a lithium compound of 1.2 parts by mass or less in terms of oxygen, The second region is a coil component containing a non-magnetic material.

2. The amount of the lithium compound in the aforementioned auxiliary component is Li per 100 parts by mass of the main component. ２ The coil component according to claim 1, wherein the amount is 0.005 to 0.50 parts by mass in terms of oxygen.

3. The coil component according to claim 1, wherein the non-magnetic material includes a glass-based material.

4. The coil component according to claim 1, wherein the non-magnetic material has a permeability and relative permittivity that are smaller than, respectively, those of the ferrite composition.

5. The coil is arranged such that the coil axis is aligned in a direction in which the pair of end faces face each other. The element includes a pair of first element portions, each containing a corresponding end face from the pair of end faces, and a second element portion located between the pair of first element portions. The second element portion includes the first region and the second region, The coil component according to claim 1, wherein the at least one coil conductor includes a coil conductor disposed in the second element portion.

6. The coil component according to claim 5, wherein the central portion of the three parts obtained by dividing the second body portion into three equal parts in the direction along the coil axis includes the second region.

7. The coil component according to claim 6, wherein each of the three parts includes the first region and the second region.

8. The coil component according to claim 5, wherein the second region includes a plurality of regions provided at different positions in the direction along the coil axis.

9. The coil component according to claim 8, wherein the plurality of regions are provided symmetrically with respect to the central position of the length of the second body portion in the direction along the coil axis.

10. The coil component according to claim 8 or 9, wherein the plurality of regions are provided at substantially equal intervals in the direction along the coil axis.

11. The coil component according to claim 8, wherein the plurality of regions are provided so as to be biased toward one of the pair of first elemental parts.

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