Ferrite composition, magnetic core, electronic component, and power supply

Abstract

To provide a ferrite composition that can reduce magnetic loss in a larger magnetic core, and also to provide a magnetic core, an electronic component, and a power supply having the composition.SOLUTION: A ferrite composition has a main component and a sub-component. The main component includes 52.0 to 53.5 mol% of iron oxide in terms of Fe2O3, 6.0 to 11.0 mol% of zinc oxide in terms of ZnO, and manganese oxide as the balance. The ferrite composition contains, as the sub-component relative to 100 pts.mass of the main component, cobalt, titanium, silicon, calcium, vanadium, and tantalum, and zirconium in an amount of 0.004 pt.mass or less (including 0) in terms of ZrO2.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In recent years, electronic components containing magnetic cores are increasingly being used for applications that handle large amounts of power in the high-frequency range. To handle large amounts of power, large magnetic cores are often used. With large cores, magnetic loss increases at high temperatures when driven at high frequencies. Therefore, there is a demand for reducing magnetic loss at high temperatures.

[0003] In addition, in Patent Document 1 shown below, a high-performance Mn ferrite that reduces loss in the high-frequency range of 500 kHz or more has been developed. However, with the composition of conventional ferrite, it has been difficult to reduce magnetic loss in larger magnetic cores. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-112695 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a ferrite composition that can reduce magnetic loss at high temperatures during high-frequency operation in larger magnetic cores, and a magnetic core, electronic component, and power supply device that include the composition. [Means for solving the problem]

[0006] In order to achieve the above object, a ferrite composition according to one aspect of the present invention comprises: It has a main component and a subcomponent, The main components include 52.0 to 53.5 mol % of iron oxide calculated as Fe2O3, 6.0 to 11.0 mol % of zinc oxide calculated as ZnO, and the remainder being manganese oxide, As the subcomponent relative to 100 parts by mass of the main component, 0.1 to 0.35 parts by mass of cobalt in terms of Co3O4, 0.1 to 0.6 parts by mass of titanium in terms of TiO2, Silicon is 0.01 to 0.03 parts by mass in terms of SiO2, Calcium is 0.12 to 0.28 parts by mass in terms of CaCO3, Vanadium: 0.005 to 0.04 parts by mass in terms of V2O5, The material contains tantalum in an amount of 0.01 to 0.07 parts by mass in terms of Ta2O5, The content of zirconium is 0.004 parts by mass or less (including 0) calculated as ZrO2.

[0007] In an electronic component such as a coil device including a magnetic core made of this ferrite composition, for example, the cross-sectional area of ​​the magnetic path is 100 mm 2 The present inventors have found that even with such a large core, magnetic loss can be effectively reduced at high temperatures (e.g., 120°C or higher) during high-frequency (e.g., 500 kHz or higher) operation.

[0008] Niobium may be contained as the sub-component in an amount of 0.02 parts by weight or less in terms of Nb2O5 per 100 parts by mass of the main component. By containing niobium, magnetic loss can be further reduced.

[0009] The ferrite composition is preferably contained in a magnetic component such as a relatively large magnetic core. Examples of electronic components containing the ferrite composition include coil components, and the ferrite composition can be suitably used in power supply devices. In such electronic components or power supply devices, magnetic loss can be effectively suppressed even when a large current flows at high frequencies or in a high-temperature environment. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view of a magnetic core according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes the embodiments.

[0012] The ferrite composition according to this embodiment may be in the form of a bulk such as a sintered body, a powder, or a thin film, and the form is not particularly limited. The ferrite composition according to this embodiment has a main component and a subcomponent. The main component is composed of iron oxide, zinc oxide, and manganese oxide. Meanwhile, the subcomponent includes at least cobalt (Co), titanium (Ti), silicon (Si), calcium (Ca), vanadium (V), and tantalum (Ta). Furthermore, the subcomponent may contain niobium (Nb) and zirconium (Zr) in amounts not exceeding a predetermined amount.

[0013] First, the composition of the main components will be described. If the entire main components are taken as 100 mol%, the content of iron oxide, calculated as Fe2O3, is in the standard range of 52.0 to 53.5 mol%, and preferably 52.2 to 53.2 mol%. The content of zinc oxide, calculated as ZnO, is in the standard range of 6.0 to 11.0 mol%, preferably 7.0 to 10.5 mol%, and more preferably 8.5 to 10.0 mol%.

[0014] The manganese oxide content is determined as the remainder of the main components by determining the content of iron oxide and zinc oxide, which are the other main components. By configuring the main components with this composition, it is possible to produce a relatively large core (for example, a core with a cross-sectional area of ​​the magnetic path of 100 mm 2 Even if the magnetic loss (Pcv) at high frequencies is less than 1000kJ / s, it is possible to reduce the magnetic loss (Pcv) at high frequencies.

[0015] The above-mentioned 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 expressed by the stoichiometric composition formula AB2O4, with Mn and Zn occupying the A site and Fe occupying the B site.

[0016] On the other hand, the content of the subcomponents is expressed as a ratio to 100 parts by mass of the main component, i.e., as an outer frame amount. In this embodiment, the standard range of the Co content is 0.1 to 0.35 parts by mass in terms of Co3O4.

[0017] The standard range for the Ti content is 0.1 to 0.6 parts by mass, and preferably 0.175 to 0.450 parts by mass, calculated as TiO2. The standard range for the Si content is 0.01 to 0.03 parts by mass, and preferably 0.012 to 0.028 parts by mass, calculated as SiO2. The standard range for the Ca content is 0.12 to 0.28 parts by mass, and preferably 0.15 to 0.25 parts by mass, calculated as CaCO3.

[0018] The standard range for the V content is 0.005 to 0.04 parts by mass, and preferably 0.01 to 0.03 parts by mass, calculated as V2O5. The standard range for the Ta content is 0.01 to 0.07 parts by mass, and preferably 0.020 to 0.065 parts by mass, and more preferably 0.035 to 0.065 parts by mass, calculated as Ta2O5.

[0019] By configuring the sub-components with this composition, it is possible to make a relatively large core (for example, a core with a cross-sectional area of ​​100 mm 2 Even if the magnetic loss (Pcv) at high frequencies is less than 1000kJ / s, it is possible to reduce the magnetic loss (Pcv) at high frequencies.

[0020] Nb may be contained as a minor component. The Nb content is preferably 0.00 to 0.02 parts by mass in terms of Nb2O5, and when the Ta content is more than 0.03 parts by mass in terms of Ta2O5, it is preferably 0.01 parts by mass or less. By containing Nb in a predetermined amount or less, it is possible to further reduce magnetic loss (Pcv) at high frequencies.

[0021] Furthermore, it is preferable that the ferrite composition of this embodiment is substantially free of Zr. For example, the Zr content is preferably in a range of 0.004 parts by mass or less (including 0) calculated as ZrO2. For example, although some Zr may be unavoidably contained, by keeping the content below a predetermined ratio, magnetic loss (Pcv) at high frequencies can be reduced.

[0022] The form of existence of each minor component in the ferrite composition is not particularly limited. For example, each minor component may be solid-solved 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. More specifically, it is believed that Co and Ti are mainly solid-solved in the main component particles, and part of the Fe in the spinel lattice is substituted with the solid-solved Co or Ti.

[0023] In particular, it is thought that the simultaneous addition of Co and Ti makes it easier for Co or Ti to substitute for Fe in the B site of the spinel lattice, rather than the A site. When Fe in the spinel lattice is substituted with Co or Ti, the temperature dependence of the magnetic anisotropy constant becomes smaller, and as a result, the temperature dependence of magnetic loss is also thought to become smaller.

[0024] On the other hand, it is believed that Ca exists mainly as a compound at the grain boundaries of the main component particles and also as a solid solution near the grain boundaries of the main component particles. The presence of Ca in the above-mentioned form is believed to improve the sinterability of the ferrite composition and increase the grain boundary resistance.

[0025] Si is thought to contribute to improving 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 to function to increase the grain boundary resistance. Ta and Nb are thought to contribute to homogenizing the crystalline structure of the ferrite composition.

[0026] In addition to the above-mentioned minor components, the ferrite composition of this embodiment may contain other minor components such as P and inevitable impurities. The content of the other minor components and inevitable impurities is set to an amount that does not increase Pcv. For example, the total content of inevitable impurities is preferably about 0 to 0.001 parts by mass per 100 parts by mass of the main component.

[0027] The content of the main component and the content of the subcomponent as described above can be measured by component analysis using an X-ray fluorescence analyzer (XRF). Alternatively, they can be measured by component analysis using an electron probe microanalyzer (EPMA) during cross-sectional observation using an SEM or STEM, or by X-ray diffraction (XRD).

[0028] Next, an example of a method for producing the ferrite composition according to this embodiment will be described.

[0029] First, the starting materials for the main components are prepared and weighed so that the desired composition is obtained after firing. The starting materials for the main components can be oxide powders or powders of compounds that become oxides when heated (such as carbonate powders). Specifically, α-Fe2O3 powder, Mn3O4 powder, or ZnO powder is preferably used.

[0030] Alternatively, a powder of a composite oxide containing two or more metals may be used as the starting material for the main component. For example, a powder of a composite oxide containing Fe and Mn may be obtained by oxidizing and roasting an aqueous solution containing iron chloride and manganese chloride. ZnO powder may then be added to and mixed with this powder of the composite oxide to form the main component. The average particle size of each of the starting materials described above is preferably 0.1 to 3.0 μm.

[0031] Next, the weighed starting materials of the main components are mixed in a mixer such as a ball mill, and then calcined. In this case, the mixing may be wet or dry, and if wet mixing is selected, the mixture is appropriately dried after mixing and then calcined. The calcination conditions are preferably a holding temperature of 800 to 1100°C and a temperature holding time (temperature stabilization time) of 0.5 to 5 hours.

[0032] The calcined material obtained by calcining under these conditions is pulverized using various pulverizers until the average particle size becomes approximately 0.5 to 3.0 μm. Note that when a powder of a composite oxide containing Fe and Mn is used as the starting material of the main component, the calcination process may be omitted.

[0033] Next, the starting materials for the minor components are added to the calcined raw materials and mixed. As with the main components, oxide powders or powders of compounds that become oxides upon heating can be used as starting materials for the minor components. Specifically, Co3O4 powder, TiO2 powder, SiO2 powder, CaCO3 powder, V2O5 powder, Ta2O5 powder, and, if necessary, Nb2O5 powder can be used. The average particle size of the starting materials for the minor components is also preferably 0.1 to 3.0 μm.

[0034] The starting materials for the minor components may be added after the calcination process, and then the above-mentioned pulverization process may be performed, thereby pulverizing the calcined material while mixing the main component and the minor components. Alternatively, the starting materials for the minor components may be added after the calcined material is pulverized and mixed. Furthermore, Co3O4 powder and TiO2 powder may be mixed in advance with the starting materials for the main component and then subjected to the calcination process.

[0035] Next, a suitable binder such as polyvinyl alcohol is added to the mixed powder of the main component and the subcomponent obtained above and kneaded to obtain a composite material. This composite material is then molded into a desired shape by a method such as injection molding or mechanical press molding to obtain a molded body. For example, in injection molding, the composite material is made into a slurry 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.

[0036] Next, the molded body obtained above is fired. The firing conditions are a holding temperature of 1050°C to 1190°C and a temperature holding time of 1 to 10 hours. In addition, during the temperature rise process from the start of heating to the holding temperature, the temperature rise rate is preferably 20 to 300°C / hour, and during the temperature drop process from the holding temperature to 900°C, the cooling rate is preferably 20 to 200°C / hour.

[0037] The firing atmosphere is preferably a mixed atmosphere of oxygen and nitrogen, with the oxygen partial pressure being 0.05 to 3.0 vol% during the temperature rise and temperature hold process. Furthermore, the oxygen partial pressure is gradually reduced during the temperature drop process from the hold temperature to 1000°C, and is preferably 0.02 vol% or less at temperatures below 1000°C.

[0038] By firing under the above conditions, a ferrite composition as a sintered body can be obtained. The ferrite composition as a sintered body according to the present embodiment can be used as a part of various electronic components, such as a magnetic core (magnetic core) or a magnetic sheet.

[0039] When the ferrite composition according to the present embodiment is used as a magnetic core (magnetic core), the shape may be E-shaped, F-shaped, I-shaped, T-shaped, U-shaped, drum-shaped, toroidal, pot-shaped, cup-shaped, or simply plate-shaped or prismatic. For example, FIG. 1 shows a toroidal magnetic core 1.

[0040] The sintered body obtained after firing may be pulverized to obtain a powdered ferrite composition. In this case, a binder and a solvent may be added to the obtained sintered body powder to form a paste. This paste may then be formed into a sheet by a sheeting method, an extrusion method, or the like, and then dried or heat-treated as appropriate to obtain a thin-film ferrite composition. Such a thin-film ferrite composition may be used, for example, as a magnetic core for a thin-film inductor, or as a magnetic sheet for an antenna or a contactless power supply (for contactless power supply, electromagnetic wave absorber, noise filter).

[0041] In the ferrite composition according to this embodiment, for example, when the cross-sectional area of ​​the magnetic path is 100 mm 2 Even if the motor has such a large core, it is possible to effectively reduce magnetic loss at high temperatures (for example, 120° C. or higher) when driven at high frequencies (for example, 500 kHz or higher).

[0042] As described above, the ferrite composition of this embodiment is suitable as a magnetic core material or a magnetic sheet, and can be used in electronic components such as transformers, inductors, choke coils, reactors, antennas, and coils for contactless power supply. Among the above electronic components, the ferrite composition is particularly suitable for use as a transformer. A transformer containing the ferrite composition of this embodiment is particularly preferably 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 rectifier circuit, a smoothing circuit, and the like.

[0043] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified in various ways within the scope of the present invention. [Example]

[0044] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0045] Examples 1 to 11 In the present example, magnetic core samples were prepared from the ferrite compositions of Examples 1 to 11 having the compositions shown in Table 1, and their magnetic losses Pcv were measured. The cores of each example were prepared according to the following procedure.

[0046] First, α-Fe2O3 powder, Mn3O4 powder, and ZnO powder were prepared as starting materials for the main components and weighed out to achieve the desired ratio after firing. The weighed powders were then wet-mixed in a ball mill to obtain a raw material mixture. After drying, this raw material mixture was calcined in air at 900°C for 3 hours to obtain a calcined material.

[0047] Next, the calcined material was placed in a ball mill filled with steel balls and milled for 16 hours to obtain a milled powder with an average particle size of 1-2 μm. This milled powder was then wet-mixed with the starting materials for the minor components and then dried to obtain a mixed powder. The starting materials for the minor components were Co3O4 powder, TiO2 powder, SiO2 powder, CaCO3 powder, V2O5 powder, and Ta2O5 powder, which were weighed out to achieve the desired ratio after firing.

[0048] Next, 0.8 parts by mass of polyvinyl alcohol was added to 100 parts by mass of the mixed powder, and the mixture was sprayed and dried using a spray dryer to form granules. The resulting granules were then filled into a mold and molded under a pressure of 100 MPa to obtain a toroidal molded body.

[0049] Next, the above-mentioned compact was sintered under the following conditions. The sintering conditions were a holding temperature of 1150°C, a holding time of 5 hours, and a sintering atmosphere of a mixed atmosphere of oxygen and nitrogen. The oxygen partial pressure during the temperature holding process was 1 vol%, and during the temperature decreasing process, the oxygen partial pressure was monotonically decreased in the temperature range of 1150°C to 1000°C, and controlled so that the oxygen partial pressure was 0.02 vol% in the temperature range below 1000°C. The temperature increase rate was 100°C / hour, and the cooling rate was 100°C / hour. By sintering under these conditions, a magnetic core sample made of the ferrite composition as a sintered body was obtained.

[0050] The shape of the obtained core sample was toroidal as described above. The dimensions of the produced core were an outer diameter of 51 mm, an inner diameter of 31 mm, a thickness of 11 mm, and a magnetic path cross-sectional area of ​​110 mm. 2 A core sample of this size is referred to as a large core in Table 6 below.

[0051] The compositions of the produced cores were analyzed by XRF. The measurement results are shown in Table 1. The magnetic loss Pcv of each core sample was measured at 120°C under conditions of a frequency of 500 kHz and a magnetic flux density of 50 T using a BH analyzer manufactured by Iwasaki Electric Co., Ltd. The measurement results are shown in Table 1.

[0052] Comparative Examples 1 to 5 As shown in Table 1, in Comparative Examples 1 to 5, element samples were produced in the same manner as in Example 1, except that starting materials were prepared so that the Fe2O3 content in the sintered core samples was outside the range of 52.0 to 53.5 mol% or the ZnO content was outside the range of 6.0 to 11.0 mol%, and then the same tests and evaluations were carried out as in Example 1. The results are shown in Table 1.

[0053] Rating 1

[0054] As shown in Table 1, it was confirmed that Examples 1 to 11, in which the main component was within the specified range (52.0 to 53.5 mol% in terms of Fe2O3, 6.0 to 11.0 mol% in terms of ZnO, the remainder being manganese oxide), had a smaller Pcv than Comparative Examples 1 to 5, which were outside the specified range. Note that a magnetic loss Pcv value of 173 or less was considered good, and it was confirmed that all of the Examples (Examples 1 to 45) shown below had a smaller Pcv than all of the Comparative Examples (Comparative Examples 1 to 23).

[0055] It was also confirmed that the Pcv of iron oxide was particularly small when the content was in the range of 52.2 to 53.2 mol% in terms of Fe2O3, and that the Pcv of zinc oxide was particularly small when the content was in the range of 7.0 to 10.5 mol% and further in the range of 8.5 to 10.0 mol% in terms of ZnO.

[0056] [Table 1]

[0057] Examples 12 to 14 As shown in Table 2, in the sintered core sample, the starting materials were prepared so that the cobalt content, calculated as Co3O4, was in the range of 0.1 to 0.35 parts by mass per 100 parts by mass of the main component, and element samples were fabricated in the same manner as in Example 6, and tests and evaluations were carried out in the same manner as in Example 6. The results are shown in Table 2.

[0058] Comparative Examples 6 and 7 As shown in Table 2, in Comparative Examples 6 and 7, starting materials were prepared so that the cobalt content in the sintered core samples was outside the range of 0.1 to 0.35 parts by mass in terms of Co3O4. Except for this, element samples were produced in the same manner as in Example 6, and tests and evaluations similar to those in Example 6 were carried out. The results are shown in Table 2.

[0059] Rating 2 As shown in Table 2, it was confirmed that Examples 6 and 12 to 14, which were in the range of 0.10 to 0.35 parts by weight in terms of Co3O4, had smaller Pcv than Comparative Examples 6 and 7, which were outside that range.

[0060] [Table 2]

[0061] Examples 15 to 18 As shown in Table 3, element samples were produced in the same manner as in Example 6, except that starting materials were prepared so that the titanium content in the sintered core sample was in the range of 0.1 to 0.6 parts by mass, converted to TiO2, as shown in Table 3. The same tests and evaluations as in Example 6 were carried out. The results are shown in Table 3.

[0062] Comparative Examples 8 and 9 As shown in Table 3, in Comparative Examples 8 and 9, element samples were produced in the same manner as in Example 6, except that starting materials were prepared so that the TiO2 content in the sintered core samples was outside the range of 0.1 to 0.6 parts by mass, and the same tests and evaluations were carried out as in Example 6. The results are shown in Table 3.

[0063] Rating 3 As shown in Table 3, it was confirmed that Examples 6 and 15 to 18, which were in the range of 0.1 to 0.6 parts by mass in terms of TiO2, had smaller Pcv than Comparative Examples 8 and 9, which were outside that range. It was also confirmed that Pcv was particularly small when the range was 0.175 to 0.450 parts by mass in terms of TiO2.

[0064] [Table 3]

[0065] Examples 19 to 26 As shown in Table 4, starting materials were prepared so that the silicon content in the sintered core sample was in the range of 0.01 to 0.03 parts by mass in terms of SiO2, or the calcium content in the range of 0.12 to 0.28 parts by mass in terms of CaCO3. Except for this, element samples were fabricated in the same manner as in Example 6, and tests and evaluations similar to those in Example 6 were carried out. The results are shown in Table 4.

[0066] Comparative Examples 10 to 15 As shown in Table 4, in Comparative Examples 10 to 15, element samples were produced in the same manner as in Example 6, except that starting materials were prepared so that the silicon content or calcium content in the sintered core samples was outside the ranges of Examples 19 to 26. The results are shown in Table 4.

[0067] Rating 4 As shown in Table 4, Examples 6 and 19-26, in which the silicon content was in the range of 0.01 to 0.03 parts by mass in terms of SiO2, or the calcium content was in the range of 0.12 to 0.28 parts by mass in terms of CaCO3, showed lower Pcv values ​​than Comparative Examples 10 to 15, which were outside these ranges. Furthermore, it was confirmed that the Pcv was particularly small for silicon in the range of 0.012 to 0.028 parts by mass in terms of SiO2. Furthermore, it was confirmed that the Pcv was particularly small for calcium in the range of 0.15 to 0.25 parts by mass in terms of CaCO3.

[0068] [Table 4]

[0069] Examples 27 to 37 As shown in Table 5, starting materials were prepared so that the vanadium content in the sintered core sample was in the range of 0.005 to 0.04 parts by mass, calculated as V2O5, or the tantalum content was in the range of 0.01 to 0.07 parts by mass, calculated as Ta2O5, and element samples were fabricated in the same manner as in Example 6, and tests and evaluations were carried out in the same manner as in Example 6. The results are shown in Table 5.

[0070] Comparative Examples 16 to 19 As shown in Table 4, in Comparative Examples 16 to 19, starting materials were prepared so that the vanadium content or tantalum content in the sintered core samples was outside the range of Examples 27 to 37. Except for this, element samples were produced in the same manner as in Example 6, and tests and evaluations were carried out in the same manner as in Example 6. The results are shown in Table 5.

[0071] Rating 5 As shown in Table 5, it was confirmed that Examples 6 and 27 to 37, in which the vanadium content was in the range of 0.005 to 0.04 parts by mass in terms of V2O5, or the tantalum content was in the range of 0.01 to 0.07 parts by mass in terms of Ta2O5, had smaller Pcv than Comparative Examples 16 to 19, which were outside those ranges.

[0072] It was also confirmed that the Pcv of vanadium was particularly small when the content was in the range of 0.01 to 0.03 parts by mass in terms of V2O5, and that the Pcv of tantalum was particularly small when the content was in the range of 0.020 to 0.065 parts by mass, more preferably 0.035 to 0.065 parts by mass in terms of Ta2O5.

[0073] [Table 5]

[0074] Examples 38 to 41 As shown in Table 5, starting materials were prepared so that the niobium content in the sintered core sample was in the range of 0.01 to 0.02 parts by mass, calculated as Nb2O5, and the tantalum content was 0.01 or 0.03 parts by mass, calculated as Ta2O5. Except for this, element samples were fabricated in the same manner as in Example 6, and tests and evaluations similar to those in Example 6 were carried out. The results are shown in Table 5.

[0075] Rating 6 As shown in Table 5, it was confirmed that the Nb content is preferably 0.00 to 0.02 parts by mass in terms of Nb2O5, and when the Ta content is more than 0.03 parts by mass in terms of Ta2O5, it is preferably 0.01 parts by mass or less.

[0076] Example 42 and Comparative Example 20 As shown in Table 5, starting materials were prepared so that the Zr contents in the sintered core samples were 0.004 and 0.01 parts by mass, calculated as ZrO2, and other elements were fabricated in the same manner as in Example 6, and tests and evaluations were carried out in the same manner as in Example 6. The results are shown in Table 5.

[0077] Rating 7 As shown in Table 5, it was confirmed that the Zr content is preferably 0.000 to 0.004 parts by mass in terms of ZrO2, and is preferably substantially 0.

[0078] Examples 43 to 45, Comparative Examples 21 to 23 Starting materials were prepared so that the contents of titanium, silicon, vanadium, and tantalum in the sintered core samples would be the converted values ​​shown in Table 6, and three types of molds were used to mold the core samples into the following small, medium, and large core sizes. Except for this, element samples were produced in the same manner as in Example 14, and tests and evaluations similar to those in Example 14 were carried out. The results are shown in Table 6.

[0079] Here, the "three types of molds" refer to three types of molds: a mold for obtaining a smaller-sized "small core," a mold for obtaining a larger-sized "large core," and a mold for obtaining a "medium core" that is a size between the "small core" and the "large core." The dimensions of the cores produced were: outer diameter 51 mm, inner diameter 31 mm, thickness 11 mm, and magnetic path cross-sectional area 110 mm. 2 The core is a medium core with an outer diameter of 37 mm, an inner diameter of 23 mm, a thickness of 10.5 mm, and a magnetic path cross-sectional area of ​​73.5 mm. 2 The small core has an outer diameter of 25 mm, an inner diameter of 13 mm, a thickness of 6 mm, and a magnetic path cross-sectional area of ​​36 mm. 2 It was.

[0080] Rating 9 As shown in Table 6, in Examples 43 to 45, compared with Comparative Examples 21 to 23 in which the range of Ta was outside the predetermined reference range, the large core (magnetic path cross-sectional area of ​​100 mm 2It was confirmed that Pcv was small in the above cases.

[0081] [Table 6] [Explanation of symbols]

[0082] 1... Magnetic core

Claims

1. It has a main component and a subcomponent, The main component is Fe 2 O 3 52.0 to 53.5 mol % iron oxide calculated as iron oxide, 6.0 to 11.0 mol % zinc oxide calculated as ZnO, and the remainder manganese oxide, As the subcomponent relative to 100 parts by mass of the main component, Cobalt 3 O 4 converted to 0.1 to 0.35 parts by mass, Titanium is TiO 2 converted to 0.1 to 0.6 parts by mass, Silicon is converted to SiO 2 converted to 0.01 to 0.03 parts by mass, Calcium as CaCO 3 Converted to 0.12 to 0.28 parts by mass, Vanadium V 2 O 5 converted to 0.005 to 0.04 parts by mass, Tantalum as Ta 2 O 5 The content is 0.01 to 0.07 parts by mass, calculated as Zirconium is ZrO 2 The ferrite composition has a content of 0.004 parts by mass or less (including 0) in terms of the total mass of the ferrite.

2. Niobium is added as the auxiliary component to 100 parts by mass of the main component. 2 O 5 The ferrite composition according to claim 1, wherein the content is 0.00 to 0.02 in terms of Mo.

3. A magnetic core comprising the ferrite composition according to claim 1 or 2.

4. An electronic component comprising the ferrite composition according to claim 1 or 2.

5. A power supply device comprising the ferrite composition according to claim 1 or 2.

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