Ferrite compositions, electronic components, and power supplies

Abstract

To provide a ferrite composition that can reduce changes in eddy current loss due to differences in core size or shape, an electronic component using the ferrite composition, and a power supply device using the electronic component. [Solution] A ferrite composition having a main component, a first minor component, and a second minor component, wherein the main component is composed of 51.0 to 53.5 mol% iron oxide, 7 to 16.5 mol% zinc oxide, and the remainder being manganese oxide, and per 100 parts by mass of the main component, the first minor component contains 0.09 to 0.27 parts by mass of cobalt and 0.13 to 0.45 parts by mass of titanium, and per 100 parts by mass of the main component, the second minor component contains y parts by mass of silicon, niobium, vanadium, and calcium, the average crystal grain size is x μm, y is 0.10 to 0.32, x is 6 to 18, and y and x satisfy formulas (1) and (2).

Description

[Technical Field]

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

[0002] In recent years, as electronic devices have become smaller and more efficient, there is a strong demand for miniaturization and increased efficiency in electronic components used in power supplies and other devices. To achieve miniaturization and increased efficiency, ferrite sintered bodies used in electronic components such as coils and transformers are required to have low loss characteristics.

[0003] Generally, the core loss Pcv of a ferrite composition consists of hysteresis loss Phv, eddy current loss Pev, and residual loss Prv, and the eddy current loss Pev varies greatly depending on the size or shape of the core. With conventional techniques, it has not been possible to suppress the change in eddy current loss Pev due to differences in core size or shape, and in many cases, the values ​​that were designed could not be obtained when actually fabricating ferrite cores.

[0004] Patent Document 1 describes how low losses at 300kHz-100mT, 100℃ are achieved by adjusting the main component that reduces magnetic anisotropy and magnetostriction, adjusting the secondary component that provides sufficient electrical resistivity, and controlling the amount of unavoidable impurities.

[0005] Furthermore, Patent Document 2 focuses on preventing thermal runaway of transformers, and reduces losses at temperatures above 120°C by simultaneously adding CoO and TiO2.

[0006] Furthermore, Patent Document 3 describes how loss reduction at 100-300 kHz is achieved with a composition in which CoO and TiO2 are simultaneously added.

[0007] Furthermore, Patent Document 4 describes how volume resistivity and average grain size are optimized to reduce losses over a wide temperature range.

[0008] However, Patent Documents 1 to 4 do not examine the changes in eddy current loss due to differences in core shape. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 6730545 [Patent Document 2] Patent No. 5786322 [Patent Document 3] Japanese Patent Publication No. 2004-35372 [Patent Document 4] International Publication No. 2017 / 164350 [Overview of the project] [Problems that the invention aims to solve]

[0010] This invention has been made in view of the above circumstances, and its objective is to provide a ferrite composition that can reduce changes in eddy current loss due to differences in core size or shape, an electronic component using the ferrite composition, and a power supply device using the electronic component. [Means for solving the problem]

[0011] To achieve the above objective, the ferrite composition according to the present invention It has a main component, a first minor component, and a second minor component. The aforementioned main component consists of 51.0 to 53.5 mol% iron oxide (based on Fe2O3), 7 to 16.5 mol% zinc oxide (based on ZnO), and the remainder being manganese oxide. With respect to 100 parts by mass of the main component, the first minor component contains 0.09 to 0.27 parts by mass of cobalt (calculated as CoO) and 0.13 to 0.45 parts by mass of titanium (calculated as TiO2). With respect to 100 parts by mass of the main component, the second minor component contains y parts by mass of silicon, niobium, vanadium, and calcium, calculated in terms of SiO2, Nb2O5, V2O5, and CaCO3, respectively. The average crystal grain size is x μm, The aforementioned y is between 0.10 and 0.32. The aforementioned x ranges from 6 to 18. The aforementioned y and x satisfy the following equations (1) and (2): The electrical resistivity is 5 Ω·m or greater. y + 0.014x ≥ 0.229 ···(1) y + 0.020x ≤ 0.549 ···(2)

[0012] Generally, product design is based on the characteristics of cores with relatively small magnetic path cross-sectional areas. However, actual products often have large magnetic path cross-sectional areas, and their shapes are often complex, resulting in non-uniform magnetic path cross-sectional areas. Therefore, the characteristics at the product design stage may not match those of the actual product. In contrast, the ferrite composition according to the present invention, having the above-described structure, can reduce the change in eddy current loss due to differences in core shape or size; that is, it can suppress changes in eddy current loss due to differences in core size or shape.

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

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

[0015] The ferrite composition according to this 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 this 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, the first sub-component includes at least cobalt (Co) and titanium (Ti). Further, the second sub-component includes silicon (Si), niobium (Nb), vanadium (V), and calcium (Ca). Hereinafter, 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 rate of iron oxide is in a reference range of 51.0 to 53.5 mol% in terms of Fe2O3, preferably 51.25 to 52.8 mol%. The content rate of zinc oxide is in a reference range of 7 to 16.5 mol% in terms of ZnO, preferably 8.6 to 14 mol%, more preferably 8.6 to 12 mol%. Also, the content rate of manganese oxide is determined as the remainder of the main component by determining the content rates of iron oxide and zinc oxide, which are the other main components.

[0017] The above-mentioned main component constitutes 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 AB2O4, in which Mn and Zn enter the A site and Fe enters the B site. In this embodiment, the main component particles of the spinel structure have an average particle size in terms of the equivalent circle diameter of x μm, where x is 6 to 18, preferably 7.5 to 14. The average particle size 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) etc. and performing image analysis on the obtained cross-sectional photograph.

[0018] On the other hand, the content ratio of the first sub-component is represented as the ratio with respect to 100 parts by mass of the above main component, that is, as the outer frame amount. In this embodiment, the content ratio of Co has a reference range of 0.09 to 0.27 parts by mass in terms of CoO, preferably 0.13 to 0.27 parts by mass, and more preferably 0.21 to 0.27 parts by mass. Further, the content ratio of Ti has a reference range of 0.13 to 0.45 parts by mass in terms of TiO2, preferably 0.13 to 0.35 parts by mass, and more preferably 0.13 to 0.225 parts by mass.

[0019] Also, the content ratio of the second sub-component is also represented as the ratio with respect to 100 parts by mass of the above main component, that is, as the outer frame amount. Specifically, with respect to 100 parts by mass of the main component, as the second sub-component, the total amount of Si, Nb, V, and Ca, each converted into SiO2, Nb2O5, V2O5, and CaCO3, is y parts by mass, and y is preferably 0.10 to 0.32, and 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, carbonates, etc. 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, Ca is thought to exist mainly as a compound at the grain boundaries of the main component particles, as well as in solid solution near the grain boundaries of the main component particles. The presence of Ca in the above forms is thought to improve the sinterability of the ferrite composition and increase grain boundary resistance. Nb is thought to contribute to the homogenization of the crystal structure of the ferrite composition. Si is thought to contribute to the improvement of the sinterability of the ferrite composition. V is thought to exist mainly as a compound at the grain boundaries of the main component particles and is thought to play a role in increasing grain boundary resistance.

[0023] Furthermore, it is preferable that the ferrite composition of this embodiment is substantially free of Zr. In this embodiment, "substantially free of Zr" means that the Zr content is 0.009 parts by mass or less in terms of ZrO2 per 100 parts by mass of the main component. More preferably, the Zr content is less than 0 to 0.005 parts by mass.

[0024] In addition to the above-mentioned minor components, the ferrite composition of this embodiment may also contain other minor components such as P and unavoidable impurities. The content of the other minor components and unavoidable impurities should be in an amount that does not hinder the suppression of Pev change. For example, the total content of unavoidable impurities is preferably about 0 to 0.001 parts by mass per 100 parts by mass of the main component.

[0025] The content of the main components and minor components described above can be measured by component analysis using an X-ray fluorescence analyzer (XRF). Alternatively, it can be measured by component analysis using an electron beam microanalyzer (EPMA) during cross-sectional observation with a scanning electron microscope (SEM) or microscope (STEM), or by using X-ray diffraction (XRD).

[0026] In this embodiment, as described above, the total amount of the second minor component, calculated in terms of SiO2, Nb2O5, V2O5, and CaCO3, relative to 100 parts by mass of the main component is y parts by mass. Furthermore, the average crystal grain size of the main component particles is x μm.

[0027] In this embodiment, y and x satisfy the following equations (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 this embodiment is 5 Ω·m or higher. The method for adjusting the electrical resistivity of the ferrite composition is not particularly limited, but it can be adjusted, for example, by changing the atmosphere during firing. Specifically, lowering the oxygen partial pressure during firing tends to lower the electrical resistivity.

[0029] Next, an example of a method for producing the ferrite composition according to this embodiment will be described.

[0030] First, the starting materials for the main components are prepared and weighed to achieve the desired composition after calcination. As the starting materials for the main components, oxide powders or powders of compounds that become oxides upon heating (such as carbonate powders) can be used. Specifically, α-Fe2O3 powder, Mn3O4 powder, and ZnO powder are preferred. Alternatively, a powder of a composite oxide containing two or more metals may be used as the starting material for the main components. For example, a powder of a composite oxide containing Fe and Mn can be obtained by oxidative roasting of an aqueous solution containing iron chloride and manganese chloride. Then, ZnO powder can be added to this composite oxide powder and mixed to form the starting material for the main components. The average particle size of each of the above-mentioned starting materials is preferably 0.1 to 3.0 μm.

[0031] Next, the weighed starting materials for the main components are mixed in a mixer such as a ball mill, and then calcined. The mixing can be wet or dry; if wet mixing is chosen, the mixture is dried appropriately after mixing before the calcination. The calcination conditions are preferably a holding temperature of 800-1100°C and a holding time (temperature stabilization time) of 0.5-5 hours. The calcined material obtained under these conditions is then pulverized using various grinders until the average particle size is approximately 0.5-3.0 μm. Note that if a complex oxide powder containing Fe and Mn is used as the starting material for the main components, the calcination process may be omitted.

[0032] Next, the starting materials for the secondary components are added to the calcined raw material and mixed. As with the main component, oxide powders or powders of compounds that become oxides upon heating can be used as the starting materials for the secondary components. Specifically, CoO powder, TiO2 powder, SiO2 powder, Nb2O5 powder, V2O5 powder, and CaCO3 powder can be used. The average particle size of the starting materials for the secondary components is preferably 0.1 to 3.0 μm. The starting materials for the secondary components may be added after the calcination treatment, and then the calcined material may be crushed while mixing the main component and the secondary components by the crushing treatment described above. Alternatively, the starting materials for the secondary components may be added and mixed after the crushing of the calcined material. Furthermore, CoO powder and TiO2 powder may be mixed with the starting materials for the main component beforehand and then subjected to the calcination treatment.

[0033] Next, a suitable binder, such as polyvinyl alcohol, is added to the mixed powder of the main and minor components obtained above and kneaded to obtain a composite material. Then, this composite material is molded into a predetermined shape by methods such as injection molding or mechanical press molding to obtain a molded body. For example, in injection molding, the above composite material is made into a slurry and poured into a mold to obtain a molded body. In mechanical press molding, 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. Furthermore, during the heating process from the start of heating to the holding temperature, the heating rate is preferably 50 to 300°C / hour, and during the cooling 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 during the heating and temperature holding processes is preferably 0.1 to 5.0 vol%. Furthermore, during the cooling process from the holding temperature to 1000°C, the oxygen partial pressure is gradually reduced, and below 1000°C, the oxygen partial pressure is preferably 0.02 vol% or less.

[0035] By firing under the conditions described above, a ferrite composition as a sintered body can be obtained. The ferrite composition as a sintered body according to this embodiment can be used as a magnetic core or 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 E-shaped, F-shaped, I-shaped, T-shaped, U-shaped, drum-shaped, toroidal, pot-shaped, cup-shaped, or simply a plate-shaped or prismatic shape.

[0037] Alternatively, the sintered body obtained after firing may be pulverized to obtain a powdered ferrite composition. In this case, a binder and solvent can be added to the obtained sintered body powder to form a paste. This paste can then be formed into a sheet using methods such as the sheet method or extrusion method, and then dried and heat-treated as appropriate to obtain a thin-film ferrite composition. Such a thin-film ferrite composition can be used, for example, as the magnetic core of a thin-film inductor, or as a magnetic sheet for antennas or contactless power supply (for contactless power supply, electromagnetic wave absorber, noise filter).

[0038] The core loss Pcv of a ferrite composition consists of hysteresis loss Phv, eddy current loss Pev, and residual loss Prv. Conventional eddy current loss Pev varies greatly depending on the size or shape of the core. Specifically, eddy current loss tends to increase as the core size increases, and in particular, eddy current loss tends to increase as the magnetic path cross-sectional area of ​​the core increases.

[0039] In contrast, the ferrite composition according to this embodiment has a predetermined content ratio of the main component, the first minor component, and the second minor component, an average crystal grain size, an electrical resistivity of a predetermined value or higher, and satisfies the above equations (1) and (2), thereby suppressing changes in eddy current loss due to differences in the size or shape of the core (magnetic core).

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

[0041] As described above, the ferrite composition of this embodiment is suitable as a magnetic core material or magnetic sheet and can be used in electronic components such as transformers, inductors, choke coils, reactors, antennas, and contactless power supply coils. Among the above electronic components, its application as a transformer is particularly suitable. A transformer containing the ferrite composition of this embodiment is particularly preferably used when incorporated into a power supply device. An example of a power supply device is a switching power supply device that combines the above-mentioned transformer with an input filter, a switching circuit, a rectifier circuit, a smoothing circuit, and the like.

[0042] While embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be modified in various ways within the scope of the present invention. [Examples]

[0043] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to the following examples.

[0044] In this experiment, ferrite cores for Examples 1-93 and Comparative Examples 1-34, 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 for each example and comparative example were prepared according to the following procedure.

[0045] First, α-Fe2O3 powder, Mn3O4 powder, and ZnO powder were prepared as the starting materials for the main components, and after calcination, they were weighed to the predetermined ratio. Then, each weighed powder was wet-mixed in a ball mill to obtain a raw material mixture. Furthermore, after drying this raw material mixture, it was calcined in an air atmosphere at 900°C for 3 hours to obtain a calcined material.

[0046] Next, the calcined material was placed in a ball mill filled with steel balls and ground for 16 hours to obtain a powder with an average particle size of 1-2 μm. This powder was then wet-mixed with the starting materials for the auxiliary components, and subsequently dried to obtain a mixed powder. For this process, CoO powder, TiO2 powder, SiO2 powder, CaCO3 powder, Nb2O5 powder, and V2O5 powder were prepared as the starting materials for the auxiliary components, and weighed in the desired ratio after calcination.

[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. The resulting granules were then filled into two types of molds and molded under pressure at a pressure of 100 MPa to obtain toroidal molded bodies.

[0048] Here, "two types of molds" refer to a mold for obtaining a smaller "small core" and a mold for obtaining a larger "large core". In other words, the above process yielded a "small molded body" that becomes a "small core" after firing, and a "large molded body" that becomes a "large core" after firing.

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

[0050] Furthermore, the shape of the obtained ferrite cores was toroidal, as described above, in both the case of small cores and large cores. The dimensions of the fabricated small and large cores were as follows. Small core: Outer diameter: 20mm, Inner diameter: 10mm, Height: 5mm, Magnetic path cross-sectional area: 25mm 2 Large core: Outer diameter: 50mm, Inner diameter: 10mm, Height: 10mm, Magnetic path cross-sectional area: 200mm 2

[0051] Furthermore, the composition of the fabricated ferrite cores was analyzed using XRF. The measurement results are shown in Tables 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21.

[0052] Furthermore, for each small core and each large core in each example and comparative example, the magnetic loss Pcv was measured at 100°C under the conditions of frequencies of 200 kHz, 300 kHz, and 400 kHz, and a magnetic flux density of 100 mT. The eddy current loss Pev was calculated using the method described below. As shown in equation (3), the magnetic loss Pcv at frequencies from 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, the hysteresis loss Phv is proportional to the frequency f, and Pev is proportional to the square of f, so 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, we can express it as equation (5). Pcv / f = Kh + Ke × f ... (5) From equation (5), since Pcv / f is a linear function of frequency f, the eddy current loss coefficient Ke can be obtained from the slope. Specifically, the eddy current loss coefficient Ke was obtained based on the magnetic loss Pcv for frequencies of 200 kHz, 300 kHz, and 400 kHz. Based on the obtained eddy current loss coefficient Ke, the eddy current loss Pev was calculated using the following equation (6). Pev = Ke × f 2 ...(6)

[0053] Furthermore, ΔPev was calculated using the following formula (7) based on the Pev of each small core and each large core in each example and comparative example. The results are shown in Tables 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, and 22. Note that ΔPev is 400 kW / m 3 The following conditions were considered favorable. ΔPev = (Pev of large core) - (Pev of small core) ... (7)

[0054] [Table 1]

[0055] [Table 2]

[0056] Tables 1 and 2 mainly show experimental results where the content of minor components was fixed and the composition of the main component was changed.

[0057] As shown in Tables 1 and 2, the main component consists of 51.0 to 53.5 mol% iron oxide (based on Fe2O3), 7 to 16.5 mol% zinc oxide (based on ZnO), and the remainder is manganese oxide. When a predetermined amount of minor components is included (Examples 1 to 11), ΔPev is 400 kW / 3 The following results were obtained, and it was confirmed that ΔPev was smaller compared to Comparative Examples 1-6.

[0058] [Table 3]

[0059] [Table 4]

[0060] [Table 5]

[0061] [Table 6]

[0062] Tables 3 to 6 show experimental results when the content of the first minor components, Co and Ti, is changed, in a case where the main components consist of 52.6 mol% iron oxide (based on Fe2O3), 9.5 mol% zinc oxide (based on ZnO), and the remainder being manganese oxide.

[0063] As shown in Tables 3 to 6, when the first minor component contains 0.09 to 0.27 parts by mass of cobalt (CoO equivalent) and 0.13 to 0.45 parts by mass of titanium (TiO2 equivalent) (Examples 12 to 24), the ΔPev is 400 kW / m². 3 The results were as follows, and it was confirmed that ΔPev was smaller compared to comparative examples 7-14.

[0064] [Table 7]

[0065] [Table 8]

[0066] Tables 7 and 8 show experimental results when the content of the first minor components, Co and Ti, is changed, in a case where the main components consist of 52.2 mol% iron oxide (based on Fe2O3), 11.5 mol% zinc oxide (based on ZnO), and the remainder being manganese oxide.

[0067] As shown in Tables 7 and 8, even when the main component consists of 52.2 mol% iron oxide (in Fe2O3 equivalent), 11.5 mol% zinc oxide (in ZnO equivalent), and the remainder being manganese oxide, if the first minor component contains 0.09 to 0.27 parts by mass of cobalt (in CoO equivalent) and 0.13 to 0.45 parts by mass of titanium (in TiO2 equivalent) (Examples 25 to 31), then ΔPev is 400 kW / m². 3 The following was confirmed:

[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 0.10 to 0.32, x is 6 to 18, and y and x satisfy equations (1) and (2) (Examples 32 to 62), ΔPev is 400 kW / m 3 or less, and it was confirmed that ΔPev was smaller compared to Comparative Examples 15 to 22.

[0076]

Table 15

[0077]

Table 16

[0078]

Table 17

[0079]

Table 18

[0080]

Table 19

[0081]

Table 20

[0082] Tables 15 to 20 show the experimental results when "y+0.014x" and "y+0.020x" are changed, assuming that the main components consist of 52.2 mol% iron oxide (based on Fe2O3), 11.5 mol% zinc oxide (based on ZnO), and the remainder being manganese oxide.

[0083] As shown in Tables 15 to 20, even when the main components consist of 52.2 mol% iron oxide (based on Fe2O3), 11.5 mol% zinc oxide (based on ZnO), and the remainder being manganese oxide, if y is 0.10 to 0.32, x is 6 to 18, and y and x satisfy equations (1) and (2) (Examples 63 to 93), then ΔPev is 400 kW / m 3 The results were as follows, and it was confirmed that ΔPev was smaller compared to comparative examples 23-30.

[0084] [Table 21]

[0085] [Table 22]

[0086] Tables 1 to 22 show that when the electrical resistivity is 5 Ω·m or higher (Examples 1 to 93), ΔPev is smaller compared to when the electrical resistivity is 4 Ω·m or lower (Comparative Examples 31 to 34).

[0087] In summary, the results from Tables 1 to 22 show that the composition of the main component, the content of the first minor component (Co, Ti) and the second minor component (Si, Nb, V, Ca), the value of x, and the value of y all satisfy the standard range of the present invention, and that x and y satisfy equations (1) and (2), and that the electrical resistivity is 5 Ω·m or more, thereby suppressing the change in eddy current loss due to differences in core size or shape. Furthermore, it was confirmed that if even one of the above elements does not satisfy the standard range, the change in eddy current loss due to differences in core size or shape increases.

Claims

1. It has a main component, a first minor component, and a second minor component. The main component is Fe 2 O 3 It is composed of 51.0 to 53.5 mol% iron oxide (converted to ZnO), 7 to 16.5 mol% zinc oxide (converted to ZnO), and the remainder being manganese oxide. For every 100 parts by mass of the main component, the first minor component consists of 0.09 to 0.27 parts by mass of cobalt (in terms of CoO equivalent) and 0.27 parts by mass of titanium (in terms of TiO equivalent). 2 It contains approximately 0.13 to 0.45 parts by mass, With respect to 100 parts by mass of the main component, as the second sub-component, silicon, niobium, vanadium and calcium are respectively in terms of SiO 2 conversion, Nb 2 O 5 conversion, V 2 O 5 conversion and CaCO 3 conversion, and the total amount contained is y parts by mass. Amount of calcium to 100 parts by mass of the main component is CaCO3 3 It contains at least 0.05 parts by mass, To 100 parts by mass of the main component, zirconium is added to ZrO 2 It contains 0.009 parts by mass or less, The average crystal grain size is x μm, The aforementioned y is between 0.10 and 0.

32. The aforementioned x ranges from 6 to 18. The aforementioned y and x satisfy the following equations (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 described in claim 1.

3. A power supply device comprising the electronic component described in claim 2.

Images