Ferrite sintered body, ferrite core, and coil component

Abstract

This ferrite sintered body has an iron oxide content of 45.0-50.0 mol% in terms of Fe2O3, a zinc oxide content of 6.0-20.0 mol% in terms of ZnO, a copper oxide content of 0-13.8 mol% in terms of CuO, and a manganese oxide content of 0.3-6.0 mol% in terms of MnO2, and has the remainder containing nickel oxide, wherein when the total content of the iron oxide, the zinc oxide, the copper oxide, the manganese oxide, and the nickel oxide is 100 parts by mass, the total of the contents of elements other than the iron oxide, the zinc oxide, the copper oxide, the manganese oxide, and the nickel oxide, in terms of oxide, is at most 2 parts by mass.

Description

Ferrite sintered bodies, ferrite cores, and coil components

[0001] This disclosure relates to ferrite sintered bodies, ferrite cores, and coil components.

[0002] In recent years, development has progressed on technologies that superimpose power and signal signals onto a single coaxial cable. For example, Patent Document 1 below discloses a coil component developed for this technology.

[0003] Japanese Patent Publication No. 2024-061157

[0004] A ferrite sintered body according to one embodiment has an iron oxide content of Fe ２ O ３ The equivalent content is 45.0 mol% to 50.0 mol%, the zinc oxide content is 6.0 mol% to 20.0 mol% in terms of ZnO, the copper oxide content is 0 mol% to 13.8 mol% in terms of CuO, and the manganese oxide content is MnO ２ The equivalent amount is 0.3 mol% to 6.0 mol%, with the remainder being nickel oxide. When the combined content of iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide is taken as 100 parts by mass, the total amount of oxides of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide is 2 parts by mass or less.

[0005] Figure 1 shows an example of a ferrite sintered body according to an embodiment. Figure 2 shows another example of a ferrite sintered body according to an embodiment.

[0006] The embodiments of the ferrite sintered body, ferrite core, and coil component disclosed herein will be described in detail below. However, the embodiments described below are not the limit of this disclosure.

[0007] In recent years, development has progressed on technologies that superimpose power and signal signals onto a single coaxial cable. For example, Patent Document 1 discloses a coil component developed for this technology.

[0008] However, in the above-mentioned conventional technology, there was still room for further improvement regarding the increase in current and frequency of the coil component. Therefore, it is expected to solve the above problems and realize a technology that can cope with the increase in current and frequency in the ferrite sintered body.

[0009] The ferrite sintered body of the present disclosure may be used, for example, in a pulse transformer for the purpose of insulation and noise removal. This pulse transformer is constituted by winding a metal wire around a ferrite sintered body as a core. This pulse transformer is used, for example, in an inductor, a transformer, a ballast, an electromagnet, a noise filter, and the like.

[0010] In recent years, this pulse transformer is also used as an in-vehicle filter. This filter functions as a protection component for removing noise on the power line, effectively filtering high-frequency noise, and ensuring a stable power supply. Therefore, the ferrite sintered body used in the filter is required to cope with an increase in current for ensuring a stable power supply.

[0011] For example, the filter is used as a filter for the electric transmission line of video data captured by an in-vehicle camera. Therefore, the ferrite sintered body used in the filter is required to cope with an increase in frequency to prevent a high-frequency image signal from flowing into the power circuit.

[0012] Here, the ferrite sintered body that becomes the ferrite core 1 of the present disclosure may have various shapes. For example, the ferrite sintered body that becomes the ferrite core 1 of the present disclosure may include a ring-shaped toroidal core shown in FIG. 1 and a bobbin-shaped bobbin core shown in FIG. 2.

[0013] The ferrite sintered body of the present disclosure may contain iron oxide, zinc oxide, manganese oxide, and nickel oxide. Further, the ferrite sintered body of the present disclosure may further contain copper oxide.

[0014] In the ferrite sintered body of the present disclosure, the content of iron oxide is Fe ２ O ３It may be 45.0 mol% to 50.0 mol% in terms of conversion. Further, in the ferrite sintered body of the present disclosure, the content of zinc oxide may be 6.0 mol% to 20.0 mol% in terms of ZnO conversion.

[0015] Further, in the ferrite sintered body of the present disclosure, the content of copper oxide may be 0 mol% to 13.8 mol% in terms of CuO conversion. Further, in the ferrite sintered body of the present disclosure, the content of manganese oxide is MnO ２ It may be 0.3 mol% to 6.0 mol% in terms of conversion. Further, the ferrite sintered body of the present disclosure may contain nickel oxide in the balance.

[0016] And, in the ferrite sintered body of the present disclosure, when the total amount of the respective contents of iron oxide, zinc oxide, copper oxide, manganese oxide and nickel oxide is 100 parts by mass, the total amount of the contents of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide and nickel oxide may be 2 parts by mass or less in terms of oxide conversion. In the present disclosure, the "total amount of the contents of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide and nickel oxide" includes the content of inevitable impurities. Further, in the present disclosure, "2 parts by mass or less" means that it is contained in an amount of 2 parts by mass or less as a component other than 100 parts by mass.

[0017] By setting the composition range of each inclusion to the above range, the ferrite sintered body of the present disclosure can increase the saturation magnetic flux density Bs. As a result, even when a large current is applied, the value of the initial permeability μ can be maintained, so that a ferrite sintered body capable of coping with a large current can be realized.

[0018] Further, by setting the composition range of each inclusion to the above range, the ferrite sintered body of the present disclosure can reduce the initial permeability μ. As a result, even in the high-frequency region, the value of the initial permeability μ can be maintained, so that a ferrite sintered body capable of coping with high frequencies can be realized.

[0019] Thus, by setting the composition range of each inclusion to the above range, the ferrite sintered body of the present disclosure can realize a ferrite sintered body capable of coping with a large current and high frequencies.

[0020] By setting the composition range of each inclusion within the above-described range, the saturation magnetic flux density Bs of the ferrite sintered body of the present disclosure can be increased. As a result, even when a large current is applied, the value of the initial permeability μ can be maintained, enabling the realization of a ferrite sintered body capable of handling large currents.

[0021] In the ferrite sintered body of the present disclosure, the content of iron oxide may be 46.3 mol% to 50.0 mol% in terms of Fe ２ O ３ conversion. Also, in the ferrite sintered body of the present disclosure, the content of zinc oxide may be 9.0 mol% to 15.0 mol% in terms of ZnO conversion.

[0022] Further, in the ferrite sintered body of the present disclosure, the content of copper oxide may be 0.1 mol% to 4.2 mol% in terms of CuO conversion. Also, in the ferrite sintered body of the present disclosure, the content of manganese oxide may be ２ 0.3 mol% to 4.7 mol% in terms of MnO

[0023] conversion. And, in the ferrite sintered body of the present disclosure, the total of the content of iron oxide in terms of Fe ２ O ３ conversion and the content of manganese oxide in terms of MnO ２ conversion may be 49.0 mol% to 54.0 mol%.

[0024] By setting the composition range of each inclusion within the above-described range, the saturation magnetic flux density Bs of the ferrite sintered body of the present disclosure can be further increased. As a result, even when a large current is applied, the value of the initial permeability μ can be well maintained, enabling the realization of a ferrite sintered body suitable for large currents.

[0025] Also, by setting the composition range of each inclusion within the above-described range, the initial permeability μ of the ferrite sintered body of the present disclosure can be further decreased. As a result, even in the high-frequency region, the value of the initial permeability μ can be well maintained, enabling the realization of a ferrite sintered body suitable for high frequencies.

[0026] Thus, by setting the composition range of each inclusion within the above-described range, a ferrite sintered body suitable for large currents and high frequencies can be realized in the ferrite sintered body of the present disclosure.

[0027] Furthermore, the ferrite sintered body of this disclosure may contain at least one of Si, Bi, Zr, and Ca, in addition to iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide. These elements may be included, for example, as unavoidable impurities or as additives.

[0028] In this disclosure, "elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide" are not limited to at least one of Si, Bi, Zr, and Ca, and may include unavoidable impurities of elements other than Si, Bi, Zr, and Ca.

[0029] Furthermore, the ferrite sintered body of this disclosure may have an initial permeability μ of 120 or less at 100 kHz and a saturation magnetic flux density Bs of 380 mT or more at 100 Hz. This makes it possible to maintain a good initial permeability μ even when a large current is applied, and also to maintain a good initial permeability μ in the high-frequency range.

[0030] Therefore, according to this embodiment, a ferrite sintered body suitable for high current and high frequency applications can be realized. Furthermore, by setting the initial magnetic permeability μ of the ferrite sintered body to 20 or higher, the output as a coil component can be maintained.

[0031] Furthermore, the ferrite core 1 according to the embodiment may be composed of a ferrite sintered body having the above-mentioned composition or characteristics. This makes it possible to realize a ferrite core 1 that can be applied to high current and high frequency applications.

[0032] Furthermore, the coil component according to this embodiment may consist of the ferrite core 1 described above and a metal wire wound around the ferrite core 1. This makes it possible to realize a coil component that can be applied to high current and high frequency applications.

[0033] The method for producing a ferrite sintered body according to this disclosure first involves preparing oxides of Fe, Zn, Cu, Mn, and Ni, or metal salts such as carbonates and nitrates that produce these oxides by calcination, as starting materials.

[0034] In this case, the average particle size of each starting material is, for example, iron oxide is Fe ２ O ３ Zinc oxide is ZnO, copper oxide is CuO, and manganese oxide is MnO ２ When nickel oxide is NiO, the thickness is 0.5 μm to 5 μm.

[0035] Furthermore, regarding zinc oxide, the ferrite sintered body contains a predetermined amount of zinc oxide due to the zinc oxide added as a starting material and the zinc oxide added as a ZnO source present at the grain boundaries after calcination. Therefore, when weighing the starting material, the amount added after calcination is subtracted before weighing.

[0036] And the iron oxide content is Fe ２ O ３ In terms of conversion, the content is 45.0 mol% to 50.0 mol%, the zinc oxide content is 6.0 mol% to 20.0 mol% in terms of ZnO, the copper oxide content is 0 mol% to 13.8 mol% in terms of CuO, and the manganese oxide content is MnO ２ Each starting material is weighed so that the equivalent amount is 0.3 to 6.0 mol%, with the remainder being nickel oxide.

[0037] Then, the weighed powders of each starting material are crushed and mixed using a ball mill or vibratory mill, and then calcined at a temperature of 700°C to 750°C for more than two hours to obtain a calcined body synthesized into ferrite.

[0038] Next, a predetermined amount of zinc oxide, which will serve as a source of ZnO at the grain boundaries, is weighed and mixed with the calcined body and solvent in a ball mill or vibratory mill. The amount of zinc oxide added is preferably 0.001 mol% to 0.02 mol% in terms of ZnO.

[0039] Furthermore, the average particle size of the zinc oxide added here is preferably 2 μm to 4 μm. The reason for setting the average particle size of zinc oxide to 2 μm to 4 μm is to ensure that the added zinc oxide does not easily dissolve in the ferrite crystal, but is instead dispersed at the grain boundaries of the ferrite sintered body.

[0040] Next, the calcined material to which zinc oxide has been added is pulverized until the average particle size is 1 μm or less, then a predetermined amount of binder is added to form a slurry, which is then granulated using a spray granulator to obtain spherical granules. Then, these spherical granules are used to press-mold a molded body of a predetermined shape.

[0041] Subsequently, the molded body is degreased in a degreasing furnace at a temperature of 400°C to 800°C to obtain a degreased body, and then fired in a firing furnace at a temperature of 1000°C to 1200°C for 2 to 5 hours to obtain the ferrite sintered body of the present disclosure.

[0042] In this firing process, it is preferable to completely cover the degreased body with a refractory material to prevent evaporation of the Fe and Zn components.

[0043] The following describes specific embodiments of this disclosure, but this disclosure is not limited to these embodiments.

[0044] Examples of the ferrite sintered body according to this disclosure are shown below.

[0045] Ferrite sintered bodies of samples No. 1 to 43, each with a different composition of its constituent materials, were prepared, and tests were conducted to measure the initial magnetic permeability μ and saturation magnetic flux density Bs.

[0046] First, as starting materials, powders of iron oxide, zinc oxide, copper oxide, manganese oxide, nickel oxide, silicon oxide, bismuth oxide, zirconium oxide, and calcium oxide, with an average particle size of 1 μm, were prepared and weighed in the proportions shown in Tables 1 and 2. For zinc oxide, the amount used as a starting material was the amount excluding the amount added after calcination.

[0047] Furthermore, in samples No. 29 to 43, silicon dioxide, bismuth oxide, zirconium oxide, or calcium oxide were added externally when the combined amount of iron oxide, zinc oxide, copper oxide, nickel oxide, and manganese oxide was 100 parts by mass. Then, each powder constituting the contents, which was weighed as the starting material, was crushed and mixed in a vibratory mill, and then calcined at 750°C for 2 hours to obtain a calcined body.

[0048] Next, the calcined material and solvent were placed in a ball mill and ground, then a binder was added to form a slurry, which was then granulated using a spray granulator to obtain spherical granules.

[0049] Next, these spherical granules were press-molded to obtain a molded body that would become a ferrite core 1 with the shape shown in Figure 1. Then, this molded body was degreased in a degreasing furnace at 600°C to obtain a degreased body. After that, the degreased bodies were placed on a firing shelf made of refractory material, completely covered with block-shaped refractory material, and then fired in a firing furnace in an atmospheric environment at 1000°C to 1200°C for 2 hours.

[0050] Subsequently, grinding was performed to obtain ferrite sintered bodies No. 1 to 43, each consisting of a ferrite core 1 with an outer diameter of 13 mm, an inner diameter of 7 mm, and a thickness of 3 mm, as shown in Figure 1.

[0051] Then, a coated copper wire with a diameter of 0.2 mm was wrapped 10 times around the entire circumference of the winding portion 1a (see Figure 1) of each sample, and the initial magnetic permeability μ at a frequency of 100 kHz was measured using an LCR meter.

[0052] Furthermore, a ferrite core 1 with the shape shown in Figure 1 was wound with coated copper wire with a diameter of 0.2 mm for 100 turns on the primary side and 30 turns on the secondary side. A power supply was connected to the primary side winding and a magnetometer to the secondary side winding, and the saturation magnetic flux density Bs was measured under conditions of 100 Hz and 100 oorsted.

[0053] Furthermore, for each sample, the amount of each metal element was determined using an X-ray fluorescence analyzer, and Fe was added to Fe. ２ O ３ Convert to Zn, convert Zn to ZnO, convert Cu to CuO, and convert Mn to MnO ２ Convert to NiO, convert Ni to SiO ２ Convert to Bi ２ O ３ Convert to ZrO ２ The conversion was performed, and Ca was converted to CaO. Then, the molar value was calculated from each molecular weight, and the proportion of each molar value in the total molar value was calculated.

[0054] As a result, the composition of each component was as shown in Tables 1 and 2. The results are shown in Tables 1 and 2.

[0055]

[0056]

[0057] Note that in Tables 1 and 2, Fe ２ O ３ The iron oxide content in the conversion is simply "Fe ２ O ３ It is stated that the zinc oxide content in terms of ZnO is simply written as "ZnO", and the copper oxide content in terms of CuO is simply written as "CuO", and MnO ２ The manganese oxide content in the conversion is simply "MnO ２ It states that the nickel oxide content in NiO equivalent is simply written as "NiO", and SiO ２ The silicon dioxide content in the conversion is simply "SiO ２ " and Bi ２ O ３ The converted bismuth oxide content is simply "Bi ２ O ３ " it says, ZrO ２ The zirconium oxide content in the conversion is simply "ZrO ２ It states that the calcium oxide content in CaO equivalent is simply listed as "CaO".

[0058] As shown in Tables 1 and 2, the iron oxide content is Fe ２ O ３ In terms of conversion, the content is 45.0 mol% to 50.0 mol%, the zinc oxide content is 6.0 mol% to 20.0 mol% in terms of ZnO, the copper oxide content is 0 mol% to 13.8 mol% in terms of CuO, and the manganese oxide content is MnO ２ Samples No. 3-8, 10-13, 15-23, 25-27, and 29-43, which contain 0.3 mol% to 6.0 mol% of nickel oxide in conversion, with the remainder being nickel oxide, and where the combined content of iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide is taken as 100 parts by mass, have an excellent balance of initial permeability μ and saturation magnetic flux density Bs, in terms of oxide content of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide.

[0059] As oxides of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide, SiO ２ It contains SiO ２ Samples No. 40 and 41, which contain less than 1 part by mass of [substance name], exhibit an excellent balance between initial permeability μ and saturation magnetic flux density Bs. As oxides of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide, [substance name] ２ O ３ It contains Bi ２ O ３ Samples No. 29 and 30, which contain less than 1 part by mass of [substance name], exhibit an excellent balance between initial permeability μ and saturation magnetic flux density Bs.

[0060] As oxides of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide, ZrO ２ It contains ZrO ２ Samples No. 32 to 35, which contain less than 2 parts by mass of [substance name], exhibit an excellent balance between initial permeability μ and saturation magnetic flux density Bs. Samples No. 37 to 39, which contain CaO as an oxide of an element other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide, and whose CaO content is less than 0.6 parts by mass, exhibit an excellent balance between initial permeability μ and saturation magnetic flux density Bs.

[0061] In contrast, samples No. 1-2, 9, 14, 24, and 28, whose iron oxide, zinc oxide, copper oxide, or manganese oxide content was outside the scope of this disclosure, showed a decrease in saturation magnetic flux density Bs or an increase in initial permeability μ.

[0062] Furthermore, as shown in Tables 1 and 2, the iron oxide content is Fe ２ O ３ In terms of conversion, the content is 46.3 mol% to 50.0 mol%, the zinc oxide content is 9.0 mol% to 15.0 mol% in terms of ZnO, the copper oxide content is 0.1 mol% to 4.2 mol% in terms of CuO, and the manganese oxide content is MnO ２ Converted to 0.3 mol% to 4.7 mol%, Fe ２ O ３ The converted iron oxide content and MnO ２Samples No. 4-8, 15-21, and 25-27, which had a total manganese oxide content of 49.0 mol% to 54.0 mol% and substantially contained oxides of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide, exhibited particularly excellent properties, with an initial magnetic permeability μ of 90 or less and a saturation magnetic flux density Bs of 390 mT or more.

[0063] When Si, Zr, and Ca are included as elements, if the content is 0.2% by mass or less in terms of oxides, the effect on the saturation magnetic flux density Bs is small, and the effect of reducing the initial permeability μ can be obtained.

[0064] Although the present disclosure has been described in detail above, this disclosure is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the gist of this disclosure.

[0065] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of this disclosure are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents.

[0066] Furthermore, this technology can take the following configuration: (1) Iron oxide content is Fe ２ O ３ The equivalent content is 45.0 mol% to 50.0 mol%, the zinc oxide content is 6.0 mol% to 20.0 mol% in terms of ZnO, the copper oxide content is 0 mol% to 13.8 mol% in terms of CuO, and the manganese oxide content is MnO ２ (2) A ferrite sintered body in which the iron oxide content is 0.3 mol% to 6.0 mol%, the remainder being nickel oxide, and when the combined content of iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide is taken as 100 parts by mass, the total amount of oxides of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide is 2 parts by mass or less. ２ O ３The equivalent amounts are 46.3 mol% to 50.0 mol%, the zinc oxide content is 9.0 mol% to 15.0 mol% in ZnO terms, the copper oxide content is 0.1 mol% to 4.2 mol% in CuO terms, and the manganese oxide content is MnO ２ This is equivalent to 0.3 mol% to 4.7 mol%, and Fe ２ O ３ The converted iron oxide content and MnO ２ (1) The ferrite sintered body according to (1), wherein the total amount of converted manganese oxide content is 49.0 mol% to 54.0 mol%. (3) The ferrite sintered body according to (1) or (2), wherein the element other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide is at least one of Si, Bi, Zr, and Ca. (4) The ferrite sintered body according to any one of (1) to (3), wherein the initial magnetic permeability μ at 100 kHz is 20 to 120 and the saturation magnetic flux density Bs at 100 Hz is 380 mT or more. (5) A ferrite core composed of the ferrite sintered body according to any one of (1) to (4). (6) A coil component comprising the ferrite core according to (5), and a metal wire wound around the ferrite core.

[0067] 1. Ferrite core

Claims

1. Iron oxide content is Fe ２ O ３ The equivalent content is 45.0 mol% to 50.0 mol%, the zinc oxide content is 6.0 mol% to 20.0 mol% in terms of ZnO, the copper oxide content is 0 mol% to 13.8 mol% in terms of CuO, and the manganese oxide content is MnO ２ A ferrite sintered body having an equivalent content of 0.3 mol% to 6.0 mol%, with the remainder being nickel oxide, and where, when the combined content of iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide is taken as 100 parts by mass, the total amount of oxides of elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide is 2 parts by mass or less.

2. The content of iron oxide is Fe ２ O ３ in terms of conversion, it is 46.3 mol% to 50.0 mol%, the content of zinc oxide is 9.0 mol% to 15.0 mol% in terms of ZnO conversion, the content of copper oxide is 0.1 mol% to 4.2 mol% in terms of CuO conversion, the content of manganese oxide is MnO ２ in terms of conversion, it is 0.3 mol% to 4.7 mol%, Fe ２ O ３ The ferrite sintered body according to claim 1, wherein the total of the content of iron oxide in terms of ２ conversion and the content of manganese oxide in terms of MnO conversion is 49.0 mol% to 54.0 mol%.

3. The ferrite sintered body according to claim 1 or 2, wherein the elements other than iron oxide, zinc oxide, copper oxide, manganese oxide, and nickel oxide contain at least one of Si, Bi, Zr, and Ca.

4. A ferrite sintered body according to any one of claims 1 to 3, wherein the initial magnetic permeability μ at 100 kHz is 20 to 120 and the saturation magnetic flux density Bs at 100 Hz is 380 mT or more.

5. A ferrite core composed of a ferrite sintered body according to any one of claims 1 to 4.

6. A coil component comprising: a ferrite core as described in claim 5; and a metal wire wound around the ferrite core.

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