Ferrite composition, electronic component and power supply

Abstract

To provide a ferrite composition capable of reducing the change of eddy current loss due to a difference in the size or shape of a core; an electronic component using the ferrite composition; and a power supply using the electronic component.SOLUTION: A ferrite composition has a main component, a first accessory component and a second accessory component. The main component is constituted by 51.0 to 53.5 mol% of iron oxide, 7 to 16.5 mol% of zinc oxide and the remainder consisting of manganese oxide; the first accessory component includes 0.09 to 0.27 pt.mass of cobalt and 0.13 to 0.225 pt.mass of titanium relative to 100 pts.mass of the main component; the second accessory component includes y pt(s).mass of silicon, niobium, vanadium and calcium relative to 100 pts.mass of the main component; an average grain size is x μm; y is 0.10 to 0.32; x is 6 to 18; and y and x satisfy the formulae (1) and (2).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a ferrite composition, an electronic component including the ferrite composition, and a power supply device.

Background Art

[0002] In recent years, miniaturization and high efficiency of electronic devices have progressed, and miniaturization and high efficiency are strongly required also for electronic components used in power supply devices and the like. For ferrite sintered bodies used in electronic components such as coils and transformers for miniaturization and high efficiency, low loss characteristics are required.

[0003] Generally, the core loss Pcv of a ferrite composition consists of a hysteresis loss Phv, an eddy current loss Pev, and a residual loss Prv, and the eddy current loss Pev varies greatly depending on the size or shape of the core (magnetic core). In the conventional technology, the change in the eddy current loss Pev due to the difference in the size or shape of the core cannot be suppressed, and when actually manufacturing a ferrite core, it has often been impossible to obtain the designed value.

[0004] In Patent Document 1, low loss is achieved at 300 kHz - 100 mT, 100°C by adjusting the main components with reduced magnetic anisotropy and magnetostriction, adjusting the sub-components with sufficient electrical resistivity, and controlling the amount of inevitable impurities.

[0005] Also, in Patent Document 2, with the main focus on preventing thermal runaway of a transformer, loss reduction at 120°C or higher is achieved by simultaneously adding CoO and TiO 2 .

[0006] Furthermore, in Patent Document 3, loss reduction at 100 - 300 kHz is achieved with a composition obtained by simultaneously adding CoO and TiO 2 .

[0007] Furthermore, in Patent Document 4, low loss is achieved over a wide temperature range by optimizing the volume resistivity and the average crystal grain size.

[0008] However, Patent Documents 1 to 4 do not examine the change in eddy current loss due to the difference in core shape.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0010] In view of such circumstances, the present invention has been made, and an object thereof is to provide a ferrite composition capable of reducing the change in eddy current loss due to the difference in the size or shape of the core, an electronic component using the ferrite composition, and a power supply device using the electronic component.

Means for Solving the Problems

[0011] In order to achieve the above object, the ferrite composition according to the present invention has a main component, a first sub - component, and a second sub - component, the main component is composed of 2 O 3 iron oxide in an amount of 51.0 to 53.5 mol% in terms of Fe, zinc oxide in an amount of 7 to 16.5 mol% in terms of ZnO, and the balance being manganese oxide, with respect to 100 parts by mass of the main component, as the first sub - component, cobalt in an amount of 0.09 to 0.27 parts by mass in terms of CoO, and titanium in an amount of 0.13 to 0.45 parts by mass in terms of TiO 2 are contained. With respect to 100 parts by mass of the main component, as the second sub-component, silicon, niobium, vanadium, and calcium are each in terms of SiO 2 conversion, Nb 2 O 5 conversion, V 2 O 5 conversion and CaCO 3 and the total amount in terms of conversion is contained in y parts by mass, the average crystal grain size is x μm, wherein y is 0.10 to 0.32, wherein x is 6 to 18, wherein y and x satisfy the following formulas (1) and (2), and the electrical resistivity is 5 Ω·m or more. y + 0.014x ≥ 0.229 ···(1) y + 0.020x ≤ 0.549 ···(2)

[0012] Generally, product design is carried out based on the characteristics of a core with a relatively small magnetic path cross-sectional area. However, in actual products, the magnetic path cross-sectional area is often large, and the shape is complex and the magnetic path cross-sectional area is often not uniform. For this reason, the characteristics at the product design stage and the characteristics of the actual product may not match. In contrast, the ferrite composition according to the present invention can reduce the change in eddy current loss due to differences in the shape or size of the core by having the above configuration, that is, can suppress the change in eddy current loss due to differences in the size or shape of the core.

[0013] The ferrite composition according to the present invention can be used as a magnetic core or a magnetic sheet (for non-contact power supply, electromagnetic wave absorber, noise filter, etc.) contained in various electronic components such as inductors, transformers, choke coils, reactors, antennas, and non-contact power supply coils. In particular, the ferrite composition according to the present invention is preferably used as a magnetic core of a power transformer, and this power transformer can be incorporated and used, for example, in an in-vehicle switching power supply device used in an EV (Electric Vehicle), a PHV (Plug-in Hybrid Vehicle), or a commuter (vehicle), a power supply device for household or industrial electrical equipment, or a power supply device for computer equipment.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail.

[0015] The ferrite composition according to the present embodiment may be in a bulk form such as a sintered body, a powder form, or a thin film form, and its form is not particularly limited. And the ferrite composition of the present embodiment has a main component, a first sub-component, and a second sub-component. The main component is composed of iron oxide, zinc oxide, and manganese oxide. On the other hand, as the first sub-component, at least cobalt (Co) and titanium (Ti) are included. Further, as the second sub-component, silicon (Si), niobium (Nb), vanadium (V), and calcium (Ca) are included. In the following, the first sub-component and the second sub-component may be collectively referred to as "sub-components".

[0016] First, the composition of the main component will be described. When the entire main component is 100 mol%, the content of iron oxide has a reference range of Fe 2 O 3It is 51.0 to 53.5 mol% in terms of conversion, preferably 51.25 to 52.8 mol%. The content rate of zinc oxide has a reference range of 7 to 16.5 mol% in terms of ZnO conversion, preferably 8.6 to 14 mol%, more preferably 8.6 to 12 mol%. Further, the content rate of manganese oxide is determined as the remainder among the main components by determining the content rates of iron oxide and zinc oxide, which are the other main components.

[0017] The above main components constitute main component particles having a spinel-type crystal structure in the cross-section of the ferrite composition. Here, the spinel-type crystal structure is represented by the stoichiometric composition formula AB 2 O 4 where Mn and Zn enter the A site and Fe enters the B site. In the present embodiment, the main component particles of the spinel structure have an average particle diameter in terms of equivalent circle diameter of x μm, where x is 6 to 18, preferably 7.5 to 14. Note that the average particle diameter of the main component particles can be measured by observing the cross-section of the ferrite composition with an SEM (scanning electron microscope) or STEM (scanning transmission electron microscope) and performing image analysis on the obtained cross-sectional photograph.

[0018] On the other hand, the content rate of the first sub-component is represented as the ratio with respect to 100 parts by mass of the above main components, that is, as the outer frame amount. In the present embodiment, the content rate of Co has a reference range of 0.09 to 0.27 parts by mass in terms of CoO conversion, preferably 0.13 to 0.27 parts by mass, more preferably 0.21 to 0.27 parts by mass. Also, the content rate of Ti has a reference range of 0.13 to 0.45 parts by mass in terms of TiO 2 conversion, preferably 0.13 to 0.35 parts by mass, more preferably 0.13 to 0.225 parts by mass.

[0019] Also, the content rate of the second sub-component is also represented as the ratio with respect to 100 parts by mass of the above main components, that is, as the outer frame amount. Specifically, with respect to 100 parts by mass of the main components, as the second sub-components, Si, Nb, V, and Ca are respectively in terms of SiO 2 conversion, Nb 2 O 5 conversion, V 2 O5 Conversion and CaCO 3 It contains y parts by mass of the converted total amount, and y is preferably 0.10 to 0.32, more preferably 0.115 to 0.285.

[0020] The existence form of each sub-component inside the ferrite composition is not particularly limited. For example, each sub-component may be dissolved in the main component particles, or may exist as various compounds such as oxides, composite oxides, and carbonates at the grain boundaries of the main component particles.

[0021] More specifically, Co and Ti are mainly dissolved in the main component particles, and it is considered that a part of Fe in the spinel lattice is replaced by the dissolved Co or Ti. In particular, by adding Co and Ti simultaneously, it is considered that Fe at the B-site rather than the A-site of the spinel lattice is more likely to be replaced by Co or Ti. When Fe in the spinel lattice is replaced by Co or Ti, the temperature dependence of the magnetic anisotropy constant becomes smaller, and as a result, the temperature dependence of the magnetic loss also becomes smaller.

[0022] On the other hand, for Ca, it is considered that it mainly exists as a compound at the grain boundaries of the main component particles and is dissolved in the vicinity of the grain boundaries of the main component particles. The existence of Ca in the above form is considered to improve the sinterability of the ferrite composition and increase the grain boundary resistance. Also, Nb is considered to contribute to the homogenization of the crystal structure of the ferrite composition. Si contributes to the improvement of the sinterability of the ferrite composition. Also, V is considered to mainly exist as a compound at the grain boundaries of the main component particles and to function to increase the grain boundary resistance.

[0023] Also, it is preferable that the ferrite composition of the present embodiment does not substantially contain Zr. In the present embodiment, "not substantially containing Zr" means that the content rate of Zr is 0.009 parts by mass or less in terms of ZrO 2 conversion with respect to 100 parts by mass of the main component. Note that the content rate of Zr is more preferably 0 to less than 0.005 parts by mass.

[0024] In addition to the above-described sub-components, the ferrite composition of the present embodiment may contain other sub-components such as P and inevitable impurities. The content rates of other sub-components and inevitable impurities shall be amounts that do not prevent the suppression of Pev change. For example, the total content rate of inevitable impurities is preferably about 0 to 0.001 parts by mass with respect to 100 parts by mass of the main component.

[0025] The content rates of the main component and the sub-components as described above can be measured by performing component analysis using a fluorescent X-ray analyzer (XRF). Further, at the time of cross-sectional observation with SEM or STEM, it may be measured by performing component analysis with an electron beam microanalyzer (EPMA), or it can also be measured using X-ray diffraction (XRD).

[0026] In the present embodiment, as described above, with respect to 100 parts by mass of the main component, the total amount in terms of SiO 2 conversion, Nb 2 O 5 conversion, V 2 O 5 conversion and CaCO 3 conversion is taken as y parts by mass. Also, the average crystal grain size of the main component particles is taken as x μm.

[0027] In the present embodiment, y and x satisfy the following formulas (1) and (2). y + 0.014x ≥ 0.229 ···(1) y + 0.020x ≤ 0.549 ···(2)

[0028] Furthermore, the electrical resistivity of the ferrite composition according to the present embodiment is 5 Ω·m or more. The method for adjusting the electrical resistivity of the ferrite composition is not particularly limited. For example, it can be adjusted by changing the atmosphere during firing. Specifically, when the oxygen partial pressure is lowered during firing, the electrical resistivity tends to decrease.

[0029] Next, an example of the manufacturing method of the ferrite composition according to the present embodiment will be described.

[0030] First, prepare the starting materials for the main components and weigh them so that they will have a predetermined composition after firing. As the starting materials for the main components, powders of oxides or powders of compounds that become oxides upon heating (such as carbonate powders) can be used. Specifically, α-Fe 2 O 3 powder, Mn 3 O 4 powder, and ZnO powder are preferably used. Also, powders of composite oxides containing two or more metals may be used as the starting materials for the main components. For example, an aqueous solution containing iron chloride and manganese chloride is subjected to oxidative roasting to obtain a powder of a composite oxide containing Fe and Mn. Then, by adding and mixing ZnO powder to this powder of the composite oxide, it can also be used as the raw material for the main components. Note that the average particle size of each of the above-described starting materials is preferably 0.1 to 3.0 μm.

[0031] Next, the weighed starting materials for the main components are mixed using a mixer such as a ball mill, and then calcined. At this time, the mixing may be either wet mixing or dry mixing. If wet mixing is selected, after mixing, it is appropriately dried and then calcined. Also, for the calcination treatment conditions, the holding temperature is preferably 800 to 1100°C, and the temperature holding time (temperature stabilization time) is preferably 0.5 to 5 hours. For the calcined material obtained by calcining under such conditions, it is pulverized using various pulverizers until the average particle size becomes about 0.5 to 3.0 μm. Note that when using a powder of a composite oxide containing Fe and Mn as the starting material for the main components, the calcination treatment may be omitted.

[0032] Next, starting materials for the sub-components are added to and mixed with the raw materials after calcination. As the starting materials for the sub-components, similar to the case of the main components, powders of oxides or powders of compounds that become oxides upon heating can be used. Specifically, CoO powder, TiO 2 powder, SiO 2 powder, Nb 2 O 5 powder, V 2 O 5 powder, and CaCO 3Powders can be used. Regarding the average particle size of the starting materials of the sub-components, it is preferably 0.1 to 3.0 μm. In addition, the starting materials of the sub-components may be added after the calcination treatment, and then the calcined material may be pulverized while mixing the main component and the sub-components by performing the above-mentioned pulverization treatment. Further, the starting materials of the sub-components may be added and mixed after the pulverization of the calcined material. Furthermore, the CoO powder and TiO 2 Regarding the powder, it may be premixed with the starting materials of the main component and then subjected to the calcination treatment.

[0033] Next, an appropriate binder (such as polyvinyl alcohol) is added to the mixed powder of the main component and the sub-component obtained above and kneaded to obtain a composite material. Then, this composite material is formed into a predetermined shape by a method such as injection molding or mechanical press molding to obtain a molded body. For example, in injection molding, the above composite material is slurried and poured into a mold to obtain a molded body. In mechanical press molding, a granular composite material is filled into a mold and pressurized to obtain a molded body.

[0034] Next, the molded body obtained above is fired. The firing conditions are such that the holding temperature is 1150°C to 1400°C, more preferably 1200°C to 1300°C, and the temperature holding time is 1 to 10 hours, more preferably 2 to 6 hours. Also, in the temperature rising process from the start of heating to the holding temperature, the temperature rising rate is preferably 50 to 300°C / hour, and in the temperature falling process from the holding temperature to 900°C, the cooling rate is preferably 50 to 200°C / hour. In addition, the atmosphere during firing is a mixed atmosphere of oxygen and nitrogen, and the oxygen partial pressure in the temperature rising process and the temperature holding process is preferably 0.1 to 5.0 vol%. Furthermore, in the temperature falling process from the holding temperature to 1000°C, the oxygen partial pressure is gradually decreased, and at 1000°C or lower, the oxygen partial pressure is preferably 0.02 vol% or less.

[0035] By firing under the above conditions, a ferrite composition as a sintered body is obtained. The ferrite composition as a sintered body according to this embodiment can be used as a magnetic core or a magnetic sheet in various electronic components.

[0036] When the ferrite composition according to this embodiment is used as a magnetic core, its shape can be an E shape, an F shape, an I shape, a T shape, a U shape, a drum shape, a toroidal shape, a pot shape, a cup shape, or simply a plate shape or a prismatic shape.

[0037] Note that the sintered body obtained after firing may be pulverized to obtain a powdered ferrite composition. In this case, a binder and a solvent can be further added to the obtained sintered body powder to form a paste. Then, this paste is formed into a sheet by a method such as a sheet method or an extrusion method, and then appropriately dried and heat-treated to obtain a thin-film ferrite composition. Such a thin-film ferrite composition can be used, for example, as a magnetic core of a thin-film inductor or as a magnetic sheet (for non-contact power supply, electromagnetic wave absorber, noise filter) for an antenna or non-contact power supply.

[0038] The core loss Pcv of the ferrite composition consists of a hysteresis loss Phv, an eddy current loss Pev, and a residual loss Prv. The conventional eddy current loss Pev varies greatly depending on the size or shape of the core. Specifically, the larger the size of the core, the more the eddy current loss tends to increase, and particularly, the larger the magnetic path cross-sectional area of the core, the more the eddy current loss tends to increase.

[0039] On the other hand, the ferrite composition according to this embodiment has the contents of the main component, the first sub-component, and the second sub-component, the average crystal grain size within a predetermined range, an electrical resistivity of a predetermined value or more, and moreover, by satisfying the above formulas (1) and (2) for x and y, the change in the eddy current loss due to the difference in the size or shape of the core (magnetic core) can be suppressed.

[0040] Therefore, the size and shape of the ferrite composition according to this embodiment are not particularly limited.

[0041] As described above, the ferrite composition of this embodiment is suitable as a magnetic core material or a magnetic sheet, and can be used for electronic components such as transformers, inductors, choke coils, reactors, antennas, and non-contact power supply coils. Among the above-mentioned electronic components, application as a transformer is particularly suitable. The transformer including the ferrite composition of this embodiment is particularly preferably used by being incorporated into a power supply device. Examples of the power supply device include a switching power supply device in which the above transformer is combined with an input filter, a switching circuit, a rectifying circuit, a smoothing circuit, and the like.

[0042] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

Examples

[0043] Hereinafter, the present invention will be described in more detail using examples and comparative examples. However, the present invention is not limited to the following examples.

[0044] In this experiment, ferrite cores of Examples 1 to 93 and Comparative Examples 1 to 34 having the compositions shown in Tables 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21 were prepared, and their eddy current losses Pev were measured. The ferrite cores of each example and each comparative example were produced by the following procedure.

[0045] First, as starting materials for the main components, α-Fe 2 O 3 powder, Mn 3 O 4 powder, and ZnO powder were prepared and weighed so as to have a predetermined ratio after firing. Then, the weighed powders were wet-mixed with a ball mill to obtain a raw material mixture. Further, after drying this raw material mixture, it was calcined at 900 ° C for 3 hours in an air atmosphere to obtain a calcined material.

[0046] Next, the above calcined material was put into a ball mill filled with steel balls and pulverized for 16 hours to obtain a pulverized powder with an average particle size of 1 to 2 μm. Then, this pulverized powder and the starting materials of the sub-components were wet-mixed and then dried to obtain a mixed powder. At this time, as the starting materials of the sub-components, CoO powder, TiO 2 powder, SiO 2 powder, CaCO 3 powder, Nb 2 O 5 powder, V 2 O 5 powder were prepared and weighed so as to have a predetermined ratio after firing.

[0047] Next, 0.8 parts by mass of polyvinyl alcohol was added to 100 parts by mass of the above mixed powder, and this was sprayed and dried with a spray dryer to form granules. Then, the obtained granules were filled into two types of molds respectively and pressure-molded at a pressure of 100 MPa to obtain a toroidal-shaped molded body.

[0048] Here, the "two types of molds" are a mold for obtaining a "small core" with a smaller size and a mold for obtaining a "large core" with a larger size. That is, by the above process, a "small molded body" that becomes a "small core" after firing and a "large molded body" that becomes a "large core" after firing were obtained.

[0049] Next, each of the above molded bodies ("small molded body" and "large molded body") was fired under the following conditions. The firing conditions were a holding temperature of 1250 °C, a holding time of 5 hours, and a firing atmosphere of a mixed atmosphere of oxygen and nitrogen. The oxygen partial pressure during the temperature holding process was 4 vol%, and in the temperature lowering process, the oxygen partial pressure was monotonically decreased in the temperature range of 1250 °C to 1000 °C, and was controlled so that the oxygen partial pressure became 0.02 vol% in the temperature range of 1000 °C or lower. Also, the heating rate was 200 °C / hour and the cooling rate was 100 °C / hour. By firing under such conditions, ferrite cores ("large core" and "small core") as sintered bodies were obtained.

[0050] Note that the shape of the obtained ferrite core was toroidal in both the cases of the small core and the large core as described above. Also, the dimensions of the fabricated small core and large core were as follows. Small core: outer diameter: 20 mm, inner diameter: 10 mm, height: 5 mm, magnetic path cross-sectional area: 25 mm 2 Large core: outer diameter: 50 mm, inner diameter: 10 mm, height: 10 mm, magnetic path cross-sectional area: 200 mm 2

[0051] Also, for the fabricated ferrite core, its composition was analyzed by XRF. The measurement results are shown in Tables 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21.

[0052] Also, for each small core and each large core of each example and each comparative example, the magnetic loss Pcv at 100 °C was measured under the conditions of a frequency of 200 kHz, 300 kHz, 400 kHz, and a magnetic flux density of 100 mT. The eddy current loss Pev was calculated by the following method. As shown in Equation (3), the magnetic loss Pcv at frequencies of 200 kHz to 400 kHz can be expressed as the sum of the hysteresis loss Phv and the eddy current loss Pev. Pcv = Phv + Pev ···(3) Next, since the hysteresis loss Phv is proportional to the frequency f and Pev is proportional to the square of f, it can be expressed as in Equation (4). Pcv = Kh × f + Ke × f 2 ···(4) Here, Kh is the hysteresis loss coefficient and Ke is the eddy current loss coefficient. Dividing both sides of Equation (4) by the frequency f gives an expression as in Equation (5). Pcv / f = Kh + Ke × f ···(5) From Equation (5), since Pcv / f is a linear function of the frequency f, the eddy current loss coefficient Ke can be obtained from the slope. That is, based on the magnetic losses Pcv at frequencies of 200 kHz, 300 kHz, and 400 kHz, the eddy current loss coefficient Ke was obtained. Based on the obtained eddy current loss coefficient Ke, the eddy current loss Pev was calculated by the following formula (6). Pev = Ke × f 2 ···(6)

[0053] Furthermore, based on the Pev of each small core and each large core in each example and each comparative example, ΔPev was calculated by the following formula (7). The results are shown in Tables 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, and 22. When ΔPev is 400 kW / m 3 or less, it was determined to be good. ΔPev = (Pev of large core) - (Pev of small core) ···(7)

[0054]

Table 1

[0055]

Table 2

[0056] Tables 1 and 2 mainly show the experimental results of fixing the content of the secondary component and changing the composition of the main component.

[0057] As shown in Tables 1 and 2, when the main component is composed of iron oxide in terms of Fe 2 O 3 in the range of 51.0 to 53.5 mol%, zinc oxide in terms of ZnO in the range of 7 to 16.5 mol%, and the remaining manganese oxide, and contains a predetermined amount of secondary component (Examples 1 to 11), ΔPev is 400 kW / 3 or less, and it was confirmed that ΔPev is smaller compared to Comparative Examples 1 to 6.

[0058]

Table 3

[0059]

Table 4

[0060]

Table 5

[0061]

Table 6

[0062] In Tables 3 to 6, when the main components are composed of iron oxide at 52.6 mol% in terms of Fe 2 O 3 conversion, zinc oxide at 9.5 mol% in terms of ZnO conversion, and the remaining manganese oxide, the experimental results when the contents of Co and Ti, which are the first sub-components, are changed are shown.

[0063] As shown in Tables 3 to 6, when the first sub-components contain cobalt at 0.09 to 0.27 parts by mass in terms of CoO conversion and titanium at 0.13 to 0.45 parts by mass in terms of TiO 2 conversion (Examples 12 to 24), it was confirmed that ΔPev was 400 kW / m 3 or less, and ΔPev was smaller than that in Comparative Examples 7 to 14.

[0064]

Table 7

[0065]

Table 8

[0066] In Tables 7 and 8, when the main components are composed of iron oxide at 52.2 mol% in terms of Fe 2 O 3 conversion, zinc oxide at 11.5 mol% in terms of ZnO conversion, and the remaining manganese oxide, the experimental results when the contents of Co and Ti, which are the first sub-components, are changed are shown.

[0067] As shown in Tables 7 and 8, when the main components are iron oxide at 52.2 mol% in terms of Fe 2 O 3 zinc oxide at 11.5 mol% in terms of ZnO, and the balance manganese oxide, even in this case, as the first sub-component, cobalt is 0.09 to 0.27 parts by mass in terms of CoO, and titanium is TiO 2 zinc oxide at 11.5 mol% in terms of ZnO, and the balance manganese oxide, even in this case, as the first sub-component, cobalt is 0.09 to 0.27 parts by mass in terms of CoO, and titanium is TiO 3 It was confirmed that ΔPev is 400 kW / m

[0068]

Table 9

[0069]

Table 10

[0070]

Table 11

[0071]

Table 12

[0072]

Table 13

[0073]

Table 14

[0074] Tables 9 to 14 show the experimental results when "y + 0.014x" and "y + 0.020x" are changed.

[0075] As shown in Tables 9 to 14, when y is from 0.10 to 0.32, x is from 6 to 18, and y and x satisfy formulas (1) and (2) (Examples 32 to 62), ΔPev is 400 kW / m 3 or less, and it was confirmed that ΔPev was smaller than in Comparative Examples 15 to 22.

[0076]

Table 15

[0077]

Table 16

[0078]

Table 17

[0079]

Table 18

[0080]

Table 19

[0081]

Table 20

[0082] In Tables 15 to 20, when the main components are 52.2 mol% of iron oxide in terms of Fe 2 O 3 , 11.5 mol% of zinc oxide in terms of ZnO, and the balance manganese oxide, the experimental results when "y + 0.014x" and "y + 0.020x" are changed are shown.

[0083] As shown in Tables 15 to 20, when the main components are Fe 2 O 3In the case where the composition is composed of 52.2 mol % iron oxide calculated as ZnO, 11.5 mol % zinc oxide calculated as ZnO, and the remainder manganese oxide, when y is 0.10 to 0.32, x is 6 to 18, and y and x satisfy the formulas (1) and (2) (Examples 63 to 93), ΔPev is 400 kW / m 3 It was confirmed that ΔPev was smaller than those of Comparative Examples 23 to 30.

[0084] [Table 21]

[0085] [Table 22]

[0086] From Tables 1 to 22, it was confirmed that when the electrical resistivity was 5 Ω·m or more (Examples 1 to 93), ΔPev was smaller than when the electrical resistivity was 4 Ω·m or less (Comparative Examples 31 to 34).

[0087] Taking the results of Tables 1 to 22 together, it was confirmed that the change in eddy current loss due to differences in core size or shape can be suppressed when the composition of the main components, the contents of the first minor components (Co, Ti) and the second minor components (Si, Nb, V, Ca), the value of x, and the value of y all satisfy the reference ranges of the present invention, when x and y satisfy formulas (1) and (2), and when the electrical resistivity is 5 Ω·m or more. It was also confirmed that when even a part of the above elements does not satisfy the reference ranges, the change in eddy current loss due to differences in core size or shape increases.

Claims

1. A main component, a first subcomponent, and a second subcomponent, The main component is Fe. 2 O 3 % of iron oxide calculated as 51.0 to 53.5 mol % of zinc oxide calculated as ZnO, and the remainder being manganese oxide, The first subcomponent is 0.09 to 0.27 parts by mass of cobalt in terms of CoO and 0.09 to 0.27 parts by mass of titanium in terms of TiO relative to 100 parts by mass of the main component. 2 The content is 0.13 to 0.225 parts by mass, The second subcomponent is composed of silicon, niobium, vanadium and calcium, each of which is mixed with SiO.sub.2 relative to 100 parts by mass of the main component. 2 Conversion, Nb 2 O 5 Conversion, V 2 O 5 Conversion and CaCO 3 The total amount converted is y parts by mass, The average grain size is x μm; The y is 0.10 to 0.32, The x is 6 to 18, The y and the x satisfy the following formulas (1) and (2), A ferrite composition having an electrical resistivity of 5 Ω·m or more. y+0.014x≧0.229...(1) y+0.020x≦0.549...(2)

2. An electronic component comprising the ferrite composition of claim 1.

3. A power supply device comprising the electronic component according to claim 2.

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