JP2023150133A - Soft magnetic particle, powder magnetic core and magnetic component - Google Patents

Abstract

To provide soft magnetic metal particles capable of providing a powder magnetic core having high heat resistance.SOLUTION: Disclosed is a soft magnetic metal particle having a core particle and an insulating film formed on the surface of the core particle. The insulating film contains a composite oxide of Si and Zr. The content ratio of Zr to the total content of Si and Zr in the insulating film is 1.0 mol% or more.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to soft magnetic metal particles, powder magnetic cores, and magnetic components.

Patent Document 1 describes soft magnetic alloy particles containing Fe, element L (Si or Zr), and element M (a metal element other than Si and Zr that is more easily oxidized than Fe), and a particle formed by partially oxidizing the particles. A magnetic material comprising an oxide film is described. The oxide film has an inner film and an outer film having different compositions.

Japanese Patent Application Publication No. 2016-195152

The present disclosure provides soft magnetic metal particles that can provide a dust core with high heat resistance.

The soft magnetic metal particles according to an embodiment of the present disclosure are
comprising a core particle and an insulating film formed on the surface of the core particle,
the insulating film contains a composite oxide of Si and Zr,
The content ratio of Zr to the total content of Si and Zr in the insulating film is 1.0 mol% or more.

The content ratio of Zr to the total content of Si and Zr in the insulating film may be 3.0 mol% or more and 20 mol% or less.

The core particles may contain Fe.

A dust core according to an embodiment of the present disclosure includes the soft magnetic metal particles described above.

A magnetic component according to an embodiment of the present disclosure includes the powder magnetic core described above.

FIG. 1 is a schematic diagram of a cross section of a powder magnetic core according to an embodiment of the present disclosure.

Embodiments of the present disclosure will be described below with reference to the drawings. The embodiments of the present disclosure described below are examples for explaining the present disclosure. Various components related to the embodiments of the present disclosure, such as numerical values, shapes, materials, manufacturing processes, etc., can be modified or changed within a range that does not cause any technical problems.

Further, the shapes etc. shown in the drawings of the present disclosure do not necessarily match the actual shapes etc. This is because the shapes and the like may have been changed for the sake of explanation.

A powder magnetic core 1 according to an embodiment of the present disclosure includes metal magnetic particles (core particles) 11 and a grain boundary phase 12, as shown in FIG. Furthermore, an insulating film 13 formed on the surface 11a of the core particle 11 is included.

A soft magnetic metal particle according to an embodiment of the present disclosure includes a core particle 11 and an insulating film 13 formed on a surface 11a of the core particle 11.

Although there are no particular restrictions on the components of the core particles 11, the core particles 11 may contain Fe. When the core particles 11 contain Fe as a main component, the saturation magnetization tends to be high. When the core particles 11 contain Fe and Si as main components, the initial magnetic permeability μi tends to be high. When the core particles 11 contain Fe and Ni as main components, the initial magnetic permeability μi tends to be high. When the core particles 11 contain Fe and Co as main components, the initial magnetic permeability μi tends to be high.

In addition, "contained as a main component" means that the content ratio of each element contained as a main component is 1% by weight or more, and the total content ratio of elements contained as a main component is 40% by weight or more, and This means that the content ratio of each element other than the elements included as the main component is lower than the content ratio of the element with the lowest content ratio among the elements included as the main component.

When the core particles 11 contain Fe as a main component, the content ratio of Fe is 40% by weight or more, and the content ratio of each element other than Fe is lower than the content ratio of Fe. Note that there are no particular restrictions on the types of components other than the main component in the core particles 11. Examples of the types of components other than the main component (Fe) include Ni, Co, Si, Zr, and V.

When the core particles 11 contain Fe and Si as main components, the content ratio of Fe is 1% by weight or more, the content ratio of Si is 1% by weight or more, and the total content ratio of Fe and Si is 40% by weight. % or more, and the content ratio of each element other than Fe and Si is lower than the content ratio of the element with a lower content ratio among Fe and Si. There is no particular restriction on the content ratio of Fe and Si in the core particles 11. The weight ratio of Si/Fe may be 0/100 to 20/80. When the weight ratio of Si/Fe is 0/100 to 10/90, saturation magnetization tends to be high. Note that there are no particular restrictions on the types of components other than the main component in the core particles 11. Examples of the types of components other than the main components (Fe and Si) include Ni, Co, Zr, and V.

When the core particles 11 contain Fe and Ni as main components, the content ratio of Fe is 1% by weight or more, the content ratio of Ni is 1% by weight or more, and the total content ratio of Fe and Ni is 40% by weight. % or more, and the content ratio of each element other than Fe and Ni is lower than the content ratio of the element with a lower content ratio among Fe and Ni. The content ratio of Fe and Ni in the core particles 11 is not particularly limited. The weight ratio of Ni/Fe may be 0/100 to 75/25. Note that there are no particular restrictions on the types of components other than the main component in the core particles 11. Examples of the types of components other than the main components (Fe and Ni) include Co, Si, Zr, and V.

When the core particles 11 contain Fe and Co as main components, the content ratio of Fe is 1% by weight or more, the content ratio of Co is 1% by weight or more, and the total content ratio of Fe and Co is 40% by weight. % or more, and the content ratio of each element other than Fe and Co is lower than the content ratio of the element with a lower content ratio among Fe and Co. There is no particular restriction on the content ratio of Fe and Co in the core particles 11. The weight ratio of Co/Fe may be 0/100 to 50/50. Note that there are no particular restrictions on the types of components other than the main component in the core particles 11. Examples of the types of components other than the main components (Fe and Co) include Ni, Si, Zr, and V.

As shown in FIG. 1, the soft magnetic metal particle has a core particle 11 and an insulating film 13 formed on the surface of the core particle 11. That is, the insulating film 13 is in contact with the surface 11a of the core particle 11 and covers the core particle 11.

The insulating film 13 does not need to cover the entire surface 11a of the core particle 11, but only needs to cover 90% or more of the entire surface 11a of the core particle 11.

Insulating film 13 contains Si oxide and Zr. Since the insulating film 13 contains Zr in addition to the Si oxide, the heat resistance of the powder magnetic core 1 becomes higher with the same thickness of the insulating film, compared to a case where the insulating film 13 does not contain Zr. In the present disclosure, "high heat resistance" of the powder magnetic core 1 means, for example, that the insulation resistance value does not easily decrease even when the powder magnetic core 1 is held in a high-temperature environment. Further, there is no particular restriction on how the powder magnetic core 1 is held in a high-temperature environment. For example, the powder magnetic core 1 may be used in a high temperature environment, or the powder magnetic core 1 may be stored in a high temperature environment.

The Si oxide contained in the insulating film 13 is not particularly limited as long as it contains a composite oxide of Si and Zr.

The Si oxide contained in the insulating film 13 may be, for example, a Si—O-based oxide (silicon oxide). Further, there is no particular restriction on the type of Si--O based oxide. For example, in addition to Si oxides such as SiO ₂ , composite oxides containing Si and other elements may be used.

Zr is contained in the insulating film 13 as a composite oxide with Si. That is, the insulating film 13 includes a composite oxide of Si and Zr. Heat resistance is improved by including Zr in the insulating film 13 as a composite oxide with Si.

The content ratio of Zr (hereinafter sometimes expressed as Zr/(Si+Zr)) to the total content of Si and Zr in the insulating film 13 is 1.0 mol% or more. When Zr/(Si+Zr) in the insulating film 13 is 1.0 mol % or more, heat resistance becomes high. Zr/(Si+Zr) in the insulating film 13 may be 3.0 mol% or more and 20 mol% or less, 3.0 mol% or more and 10 mol% or less, or 3.1 mol% or more and 10 mol% or less. good. When Zr/(Si+Zr) is within the above range, heat resistance becomes even higher.

A method for confirming that the insulating film 13 contains a composite oxide of Si and Zr will be described below.

When the insulating film 13 includes a composite oxide of Si and Zr, Si and Zr exist uniformly in the insulating film 13. The uniform presence of Si and Zr in the insulating film 13 can be confirmed, for example, by line analysis along the depth direction of the insulating film 13.

For example, a case will be described in which line analysis is performed on the insulating film 13 in which Zr/(Si+Zr) is 30 mol % with the outer surface of the insulating film 13 set at 0 nm.

When the insulating film 13 contains a composite oxide of Si and Zr, the content ratio of Zr to the total content of Si and Zr is likely to be 30 mol % no matter which part of the insulating film 13 is measured. That is, no matter which part of the insulating film 13 is measured, the content ratio of Zr to the total content of Si and Zr tends to be the same value. This is considered to be because Si and Zr are uniformly combined to form a composite oxide.

For example, if the thickness of the insulating film 13 is 75 nm or more and less than 80 nm, the line analysis results are likely to be as shown in Table A. In Table A, the content ratio of Zr to the total content of Si and Zr is listed in the Zr column, and the content ratio of Si to the total content of Si and Zr is listed in the Si column.

On the other hand, when Zr is scattered in the insulating film 13 in the form of a simple substance or a compound (excluding composite oxides of Si and Zr), there are places where Si is detected alone and places where Zr is detected alone. The detected locations are likely to be individually included in the insulating film 13.

For example, if the thickness of the insulating film 13 is 75 nm or more and less than 80 nm, the line analysis results are likely to be as shown in Table B. In Table B, the content ratio of Zr to the total content of Si and Zr is listed in the Zr column, and the content ratio of Si to the total content of Si and Zr is listed in the Si column.

When the insulating film 13 includes a composite oxide of Si and Zr, the content ratio of Zr to the total content of Si and Zr in the insulating film 13 or the content ratio of Si to the total content of Si and Zr is The portion where the content is 0.10 mol% or less is less than 10%. When the insulating film 13 does not substantially contain a complex oxide of Si and Zr, the content ratio of Zr to the total content of Si and Zr in the insulating film 13 or the content ratio of Si to the total content of Si and Zr The portion where the content ratio of is 0.10 mol% or less is 10% or more. This can be confirmed by TEM-EDS elemental mapping, for example.

In addition to Zr, the insulating film 13 may contain a metal element other than Zr. Examples include Ba, Ca, Mg, Al, Ni, Mn, and Zn whose oxides have insulating properties. Among them, Ca, Mg, Ni, Mn, and Zn are relatively easy to introduce into the insulating film. However, even if the insulating film 13 does not contain Zr but contains these metal elements, the heat resistance of the powder magnetic core 1 cannot be expected to improve as compared to the case where the insulating film 13 contains Zr. There is no particular restriction on the content of metal elements other than Zr. The content of metal elements other than Zr may be, for example, 1 mol % or less relative to the Zr content.

There is no particular limit to the thickness of the insulating film 13. For example, the thickness may be greater than or equal to 5 nm and less than or equal to 500 nm.

A grain boundary phase 12 is included between the soft magnetic metal particles included in the dust core 1 . The type of compound contained in the grain boundary phase 12 is not particularly limited, and may be silicone resin, epoxy resin, imide resin, and/or Si-O-based oxide. Furthermore, the grain boundary phase 12 may include voids. Examples of silicone resins include methyl-based silicone resins. Examples of the epoxy resin include cresol novolac. Examples of the imide resin include bismaleimide.

Note that when the resin 12 contains a silicone resin, part or all of the silicone resin contained in the grain boundary phase 12 may be modified into an Si-O-based oxide such as SiO ₂ by the heat treatment described below.

There are no particular limitations on the content of core particles 11 and the content of compounds contained in grain boundary phase 12. The content of the core particles 11 in the entire powder magnetic core 1 may be 90% by weight to 99.9% by weight. The content of the compound contained in the grain boundary phase 12 in the entire powder magnetic core 1 may be 0.1% by weight to 10% by weight.

Similar to the insulating film 13, the grain boundary phase 12 may also contain Zr.

There is no particular restriction on the method of observing the cross section of the powder magnetic core 1. For example, the powder magnetic core 1 may be observed at an appropriate magnification using SEM or TEM. Furthermore, by performing EDS analysis, the composition at each location of the powder magnetic core 1, particularly the Zr content and Si content, can be measured. Then, Zr/(Si+Zr) in the insulating film 13 can be measured. The Zr content in the core particles 11 can also be measured in a similar manner.

When measuring the content ratio of Zr present in the grain boundary phase 12, first, for example, the Zr content in the core particles 11 and the Zr content in the insulating film 13 are measured by the above measurement. Thereafter, the Zr content of the entire dust core 1 is determined by ICP. Then, by subtracting the Zr content in the entire core particles 11 and the Zr content in the entire insulating film 13 from the Zr content in the entire dust core, the content ratio of Zr present in the grain boundary phase 12 can be measured.

A method for manufacturing the powder magnetic core 1 according to this embodiment is shown below, but the method for manufacturing the powder magnetic core 1 is not limited to the following method.

First, core particles 11 are produced. There are no particular limitations on the method for producing the core particles 11, and examples thereof include gas atomization, water atomization, and the like. There are no particular restrictions on the particle size and circularity of the core particles 11. When the median particle diameter (D50) is 1 μm to 100 μm, the initial magnetic permeability μi tends to be high.

Next, coating is performed on the surface 11a of the core particle 11 to form an insulating film 13 containing Si oxide and Zr. Although there are no particular limitations on the coating method, for example, a method of applying a coating solution containing alkoxysilane and Zr to the core particles 11 is exemplified. There are no particular limitations on the method of applying the coating solution to the core particles 11, and examples include a method using spray diffusion. There are no particular restrictions on the state in which Zr is contained in the coating solution. For example, Zr may be included as zirconium alkoxide. However, when Zr is included as a metal complex having Zr as the central metal, the metal complex is difficult to decompose even by the heat treatment described below. As a result, a composite oxide of Si and Zr is less likely to be formed. The case where zirconium alkoxide is added to the coating solution will be explained below.

There are no particular limitations on the concentration of alkoxysilane, the concentration of zirconium alkoxide, and the type of solvent in the coating solution. The concentration of alkoxysilane and the concentration of zirconium alkoxide may be determined based on the desired value of Zr/(Si+Zr), the desired thickness of the insulating film 13, and the like. Examples of the alkoxysilane include monoalkoxysilane, dialkoxysilane, trialkoxysilane, and tetraalkoxysilane. Examples of the monoalkoxysilane include trimethylmethoxysilane, trimethylethoxysilane, and trimethyl(phenoxy)silane. Examples of the dialkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, t-butylmethyldimethoxysilane, and t-butylmethyldiethoxysilane. Examples of trialkoxysilane include ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, methyltrimethoxysilane, n-propyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, phenyltrimethoxysilane, etc. be done. Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetraisopropoxysilane. As the alkoxysilane, one type of alkoxysilane may be used, or two or more types of alkoxysilane may be used in combination.

Examples of the zirconium alkoxide include zirconium tetramethoxide, zirconium tetraethoxide, zirconium tetra-n-propoxide, zirconium tetraisopropoxide, and zirconium tetra-n-butoxide. As the zirconium alkoxide, one type of zirconium alkoxide may be used, or two or more types of zirconium alkoxide may be used in combination. In terms of availability, the zirconium alkoxide may be zirconium tetra-n-propoxide or zirconium tetra-n-butoxide.

Examples of the solvent include water, ethanol, and isopropyl alcohol.

Further, during spray diffusion, the proportion of alkoxysilane to the total amount of core particles 11 may be 0.1% by weight to 5% by weight. Furthermore, the film thickness of the insulating film 13 tends to increase as the amount of alkoxysilane increases.

Although there are no particular restrictions on the conditions for spray diffusion, the sol-gel reaction that forms the insulating film 13 is likely to be promoted by performing spray diffusion while performing heat treatment at 50° C. to 90° C.

The core particles 11 after spraying and diffusing the coating solution are dried to remove the solvent, and then heated at 200°C to 400°C for 1 to 10 hours, whereby a sol-gel reaction proceeds to remove Si oxides and Zr. An insulating film 13 containing the above is formed. At this time, the higher the heating temperature and the longer the heating time, the higher the density of the insulating film 13 tends to be. Moreover, before heating the core particles 11, the core particles 11 may be passed through a mesh sieve to size them.

Next, if the grain boundary phase 12 in the green compact before heat treatment, which will be described later, contains a resin, a resin solution is prepared. In addition to the silicone resin, epoxy resin and/or imide resin described above, a curing agent may be added to the resin solution. There are no particular restrictions on the type of curing agent, and examples include epichlorohydrin. Further, there are no particular limitations on the solvent for the resin solution, but a volatile solvent may be used. For example, acetone, ethanol, etc. can be used. Furthermore, when the entire resin solution is 100% by weight, the total concentration of the resin and curing agent may be 10% by weight to 80% by weight.

Furthermore, if the grain boundary phase 12 contains Zr, Zr is added to the resin solution at this point. There is no particular restriction on the state in which Zr is contained in the resin solution. For example, Zr may be included as zirconium alkoxide. Examples of the zirconium alkoxide include zirconium tetramethoxide, zirconium tetraethoxide, zirconium tetra-n-propoxide, zirconium tetraisopropoxide, and zirconium tetra-n-butoxide. As the zirconium alkoxide, one type of zirconium alkoxide may be used, or two or more types of zirconium alkoxide may be used in combination. In terms of availability, zirconium tetra-n-propoxide or zirconium tetra-n-butoxide may be used. Furthermore, by controlling the amount of Zr added, the content ratio of Zr present in the grain boundary phase can be controlled.

Next, the core particles 11 on which the insulating film 13 has been formed, that is, the soft magnetic metal particles, are mixed with a resin solution. Then, the solvent of the resin solution is evaporated to obtain granules. The obtained granules may be filled into a mold as they are, or they may be sized and then filled into a mold. There is no particular restriction on the method for sizing particles, and for example, a mesh with an opening of 45 μm to 500 μm may be used.

Next, the obtained granules are filled into a mold of a predetermined shape and pressed to obtain a green compact. The pressure during pressurization (molding pressure) is not particularly limited, and can be set to, for example, 500 MPa to 1500 MPa. The higher the compacting pressure, the higher the initial magnetic permeability μi of the powder magnetic core 1 finally obtained.

The produced powder compact may be used as a powder magnetic core. Alternatively, the produced powder compact may be heat-treated, and the sintered compact produced by the heat treatment may be used as the powder magnetic core. There are no particular restrictions on the heat treatment conditions. When a silicone resin is used as the resin, heat treatment may be performed under conditions that sinter the silicone resin. For example, heat treatment may be performed at 400° C. to 1000° C. for 0.1 hour to 10 hours. When using an epoxy resin as the resin, the epoxy resin is cured. For example, the epoxy resin is cured by leaving it at 25° C. to 250° C. for 0.1 hour to 10 hours. Furthermore, the atmosphere during curing of the epoxy resin is not particularly limited, and may be in the air or in a nitrogen atmosphere.

Although the powder magnetic core and the method for manufacturing the same according to the present embodiment have been described above, the powder magnetic core and the method for manufacturing the same according to the present disclosure are not limited to the above embodiment.

Further, there is no particular restriction on the use of the powder magnetic core of the present disclosure. Examples include magnetic components such as inductors, reactors, choke coils, and transformers. The magnetic component of the present disclosure includes the powder magnetic core described above.

Hereinafter, the present disclosure will be described based on more detailed examples, but the present disclosure is not limited to these examples.

(Experiment example 1)
As metal magnetic particles (core particles), Fe-Si alloy particles (Fe and Si (alloy particles containing as the main component) were produced by gas atomization method. Note that the median particle diameter (D50) of the Fe--Si alloy particles was 30 μm.

Next, a coating solution for forming an insulating film on the surface of the metal magnetic particles was prepared. The coating solution is a mixture of 15 parts by weight of ethanol, at least one of trimethoxysilane and zirconium tetra-n-propoxide, and 2.0 parts by weight of pure water, with the total amount of the metal magnetic particles being 100 parts by weight. It was made by The ratio of trimethoxysilane and zirconium tetra-n-propoxide was adjusted so that Zr/(Si+Zr) in the finally obtained coating film had the value shown in Table 1. Further, the total amount of trimethoxysilane and zirconium tetra-n-propoxide was set such that the thickness of the final insulating film was 50 nm.

The metal magnetic particles and the coating solution were mixed and heat-treated while being sprayed and stirred. The heat treatment temperature was 80°C and the heat treatment time was 1 hour. Further, by drying after heat treatment, metal magnetic particles having an insulating film on the surface were obtained.

However, in Comparative Example 3, the insulating film covering the metal magnetic particles was not formed. Therefore, in Comparative Example 3, the following tests were not conducted.

The obtained metal magnetic particles were passed through a 140 mesh sieve and then heat-treated. The heat treatment temperature was 300°C and the heat treatment time was 5 hours.

Next, an epoxy resin, a curing agent, and acetone were mixed to prepare a resin solution. Cresol novolak was used as the epoxy resin. Epichlorohydrin was used as a hardening agent. The epoxy resin, curing agent and acetone were mixed in a weight ratio of 10:10:80.

The total amount of the above metal magnetic particles was 100 parts by weight, and 10 parts by weight of the above resin solution was added and mixed. Next, it was dried to volatilize the acetone to obtain granules. Next, the granules were sized by passing through a 42 mesh sieve. The obtained granules were dried on a hot plate at 50° C. for 0.5 hours to produce granulated powder.

0.1 part by weight of zinc stearate was added to 100 parts by weight of the granulated powder, and molding was performed. The amount of granulated powder filled was 5 g. The molding pressure was adjusted as appropriate so that the density of the toroidal powder magnetic core finally obtained was about 6.2 g/cm ³ . The mold had a toroidal shape with an outer diameter of 17.5 mm, an inner diameter of 10.0 mm, and a thickness of 5.0 mm.

The obtained toroidal core was heat-treated at 200° C. for 2 hours to obtain a toroidal powder magnetic core. The metal magnetic particles were made to account for about 98% by weight, assuming that the entire powder magnetic core finally obtained was 100% by weight.

It was confirmed by TEM-EDS observation that there was an insulating film covering the metal magnetic particles. It was also confirmed that Zr was substantially contained only in the insulating film. Furthermore, Zr/(Si+Zr) in the insulating film was quantified by EDS. Ten measurement points were set in the insulating film 13, and Table 1 shows the results of averaging Zr/(Si+Zr) at each measurement point. Note that the size of each measurement location was 1 nm ² .

In addition, in all Examples of Experimental Example 1 and Comparative Example 2, the content ratio of Zr to the total content of Si and Zr in the insulating film or the content ratio of Si to the total content of Si and Zr was 0.10 mol%. It was confirmed that less than 10% of the locations had the following conditions. That is, it was confirmed that the insulating film contained a composite oxide of Si and Zr.

The thickness of the insulating film was measured by TEM observation. Measurement points were set on the surface of the metal magnetic particles. Then, a perpendicular line was drawn in the direction of the insulating film from the measurement point, and the length of the portion of the perpendicular line located on the insulating film was defined as the thickness of the insulating film at the measurement point. Ten measurement points were set, and the thickness of the insulating film was measured at each measurement point. Then, the average of the measured thicknesses of the insulating film was defined as the thickness of the insulating film in the metal magnetic particles. It was confirmed that the thickness of the insulating film was approximately 50 nm in all Examples and Comparative Examples.

The heat-resistant storage test was conducted by leaving the toroidal powder magnetic core in a constant temperature bath at 165° C. for 1000 hours.

After the heat-resistant storage test, In--Ga paste was applied to both surfaces of the toroidal powder magnetic core to form terminal electrodes, and then the insulation resistance was measured using HP High Resistance Meter 4339B. The results are shown in Table 1. The insulation resistance after the high temperature test was evaluated as good when it was 1.00E+08 Ω·cm or more, and even better when it was 1.00E+10 Ω·cm or more. Note that 1.00E+08 means 1.00×10 ⁸ .

The density of the toroidal powder magnetic core was calculated from the dimensions and weight of the obtained powder magnetic core. It was confirmed that it was about 6.2 g/cm ³ in all Examples and Comparative Examples.

From Table 1, when the densities of the toroidal powder magnetic cores are approximately the same, each example in which Zr/(Si+Zr) is 1.0 mol% or more, Comparative Example 1 in which the insulating film does not contain Zr, and Zr/ The insulation resistance after the heat storage test was higher than that of Comparative Example 2 in which (Si+Zr) was too small. In each example in which Zr/(Si+Zr) was 3.0 mol% or more and 20 mol% or less, the insulation resistance after the heat-resistant storage test was higher than that of the other examples.

(Experiment example 2)
In Experimental Example 2, a toroidal powder magnetic core was produced in the same manner as Experimental Example 1 except that zirconium acetylacetonate was added instead of zirconium alkoxide. The amount of zirconium acetylacetonate added was such that Zr/(Si+Zr) in the insulating film had the value shown in Table 2.

In all the comparative examples of Experimental Example 2, there were places where the content ratio of Zr to the total content of Si and Zr in the insulating film or the content ratio of Si to the total content of Si and Zr was 0.10 mol% or less. It was confirmed that it was 10% or more. That is, it was confirmed that the insulating film did not substantially contain a composite oxide of Si and Zr. Table 2 also shows the results of Examples 1, 6, and 11 of Experimental Example 1 for comparison with the case where the insulating film contains a composite oxide of Si and Zr.

From Table 2, each of the comparative examples in which the insulating film did not substantially contain a composite oxide of Si and Zr had an insulation resistance inferior to that of Experimental Example 1 after the heat-resistant storage test.

1...Powder magnetic core 11...Metal magnetic particles (core particles)
11a...Surface of metal magnetic particles 12...Grain boundary phase 13...Insulating film

Claims (5)

comprising a core particle and an insulating film formed on the surface of the core particle,
the insulating film contains a composite oxide of Si and Zr,
Soft magnetic metal particles in which the content ratio of Zr to the total content of Si and Zr in the insulating film is 1.0 mol% or more. The soft magnetic metal particles according to claim 1, wherein the content ratio of Zr to the total content of Si and Zr in the insulating film is 3.0 mol% or more and 20 mol% or less. The soft magnetic metal particle according to claim 1 or 2, wherein the core particle contains Fe. A powder magnetic core comprising the soft magnetic metal particles according to any one of claims 1 to 3. A magnetic component comprising the powder magnetic core according to claim 4.

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