TW201506962A - Soft magnetism compound and manufacturing method thereof, magnetic core, and coil-type electronic parts - Google Patents

Abstract

The purpose of the present invention is to provide a soft magnetism compound of excellent strength and the manufacturing method thereof, a magnetic core, and coil-type electronic parts. The soft magnetism compound related to the present invention has plural soft magnetism alloy granules, and crystal boundaries existing between the boundaries of the said soft magnetism alloy granules. This invention is characterized in that: the soft magnetism alloy granules are formed with Fe-Si-M series soft magnetism alloy or Fe-Ni-Si-M series soft magnetism alloy (where M is selected among at least one of Cr, Al, Ti, Co, and Ni), and the glassy phase containing Zn exists in the said crystal boundaries.

Description

Soft magnetic body composition and manufacturing method thereof, magnetic core and coil type electronic component

The present invention relates to a soft magnetic body composition, a method for producing the same, a magnetic core, and a coil type electronic component.

The metal magnetic body has an advantage in comparison with ferrite in that a high saturation magnetic flux density can be obtained. As such a metal magnetic material, a magnetic material using a soft magnetic alloy or the like is known.

Such a soft magnetic alloy expands the range of application as a magnetic material, and thus it is expected to improve the mechanical strength in the case of a molded body. Patent Document 1 proposes a magnetic material having a high strength using an Fe-Si-M-based soft magnetic alloy (wherein M is a metal element which is more easily oxidized than iron).

However, even in the form proposed in Patent Document 1, the strength is insufficient, and mechanical strength is further desired to be further improved. In particular, in such a magnetic material, there is a problem that the Si content in the Fe—Si—M-based soft magnetic alloy increases to a high electric resistance and a high magnetic permeability, and the moldability deteriorates.

Prior art literature Patent literature

Patent Document 1: Japanese Patent No. 5082002

The present invention has been made in view of such circumstances, and an object thereof is to provide a soft magnetic body composition having excellent strength, a method for producing the same, a magnetic core, and a coil type electronic component.

In order to achieve the above object, a soft magnetic composition according to the present invention is a soft magnetic composition having a plurality of soft magnetic alloy particles and a grain boundary existing between the soft magnetic alloy particles, characterized in that: The soft magnetic alloy particles are composed of a Fe—Si—M-based soft magnetic alloy or an Fe—Ni—Si—M-based soft magnetic alloy, and the above M is at least one selected from the group consisting of Cr, Al, Ti, Co, and Ni. A glassy phase containing Zn exists in the above grain boundary.

In the soft magnetic material composition according to the present invention, excellent strength is exhibited by the presence of a glassy phase containing Zn at the grain boundary of the soft magnetic alloy particles.

Preferably, Si is further present at the above grain boundaries.

Preferably, B is further present at the above grain boundaries.

Further, a method for producing a soft magnetic material composition according to the present invention includes a step of mixing a soft magnetic alloy powder, a crystallized glass, and a binder to obtain a mixture; and molding the mixture to obtain a molded body. a step; and a step of heating the molded body.

Preferably, the soft magnetic composition according to the present invention is obtained by the method for producing the above soft magnetic composition.

Further, the magnetic core according to the present invention is any of the above-mentioned The soft magnetic composition is composed of.

Further, the coil type electronic component according to the present invention has the above magnetic core.

The coil type electronic component is not particularly limited, and examples thereof include an electronic component such as an inductor component, an EMC coil component, and a transistor component. In particular, a DC-DC converter or the like for a mobile phone or the like can be suitably used.

21‧‧‧Soft magnetic alloy particles

30, 31‧‧‧ grain boundary

40‧‧‧ Glassy phase containing Zn

Fig. 1 is a view showing a magnetic core according to an embodiment of the present invention.

Fig. 2 is an enlarged cross-sectional view of an essential part of the magnetic core shown in Fig. 1;

Fig. 3 is an enlarged cross-sectional view of an essential part of the magnetic core shown in Fig. 1, and is a schematic view showing the presence of a glassy phase containing Zn.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.

The magnetic core for a coil-type electronic component according to the present embodiment is a powder magnetic core molded by powder molding. The powder molding is a method of obtaining a molded body by performing compression molding by filling a material containing a soft magnetic alloy powder into a mold of a press machine and pressurizing it at a predetermined pressure.

The shape of the magnetic core according to the present embodiment may be exemplified by an FT type, an ET type, an EI type, a UU type, an EE type, an EER type, a UI type, a drum type, or the like, in addition to the annular shape shown in FIG. Pot type, cup type, etc. By winding the winding around the core with only a predetermined number of turns, it is possible to obtain a desired coil type electronic component.

The magnetic core for a coil type electronic component according to the embodiment is composed of The soft magnetic composition according to the embodiment is configured.

The soft magnetic composition according to the embodiment is a soft magnetic composition having a plurality of soft magnetic alloy particles and a grain boundary existing between the soft magnetic alloy particles, wherein the soft magnetic alloy particles are a Fe-Si-M-based soft magnetic alloy or a Fe-Ni-Si-M-based soft magnetic alloy (wherein M is at least one selected from the group consisting of Cr, Al, Ti, Co, and Ni), and the crystal is There is a glassy phase containing Zn in the boundary.

According to the soft magnetic material composition of the present embodiment, the magnetic properties (initial magnetic permeability μi or the like) or the electrical resistivity can be favorably maintained, and the strength can be improved by satisfying the above configuration.

As shown in FIG. 2, the soft magnetic material composition according to the present embodiment has a plurality of soft magnetic alloy particles 21 and grain boundaries 30 existing between the soft magnetic alloy particles.

As shown in Fig. 3, in the present embodiment, the glassy phase 40 containing Zn exists in the grain boundary 30 formed between two particles or the grain boundary 31 existing between three or more particles (three-phase point, etc.) ). The magnetic core according to the present embodiment exhibits excellent strength due to the presence of such a Zn-containing glassy phase.

In particular, in the case of the soft magnetic composition according to the embodiment in which the glassy phase containing Zn is present at the grain boundary, in the case of the soft magnetic composition in which the glassy phase containing Zn is not present at the grain boundary The increase rate of strength is preferably 3% or more, more preferably 5% or more, and still more preferably 10% or more.

In the present embodiment, the glassy phase means a phase mainly composed of amorphous glass and/or crystallized glass. More preferably, it is a phase mainly composed of crystallized glass. Furthermore, such a glassy phase may also be derived from the composition of soft Crystallization of a metal, oxide or composite oxide of a component of a magnetic alloy or other component (binder or additive).

Further, in the present embodiment, the glassy phase contains Zn. In the glassy phase, the form of Zn is not particularly limited. For example, it may be contained as a constituent element of the amorphous glass and/or the crystallized glass, or may be used as a metal of Zn or an oxide of Zn. Or a component constituting the soft magnetic alloy and other components (such as a binder and an additive) and a composite oxide of Zn are dispersed in the glassy phase.

Further, in the soft magnetic material composition according to the embodiment, it is preferable that boron (B) is further present at the grain boundary. More preferably, B is contained in a glassy phase containing Zn. The form of the B is not particularly limited. For example, it may be contained as a constituent element of the amorphous glass and/or the crystallized glass, or may be an oxide of B or a component and other components constituting the soft magnetic alloy. (Binder, additive, etc.) and a composite oxide of B or the like are dispersed in the glassy phase.

Further, in the soft magnetic material composition according to the embodiment, it is preferable that the concentration of Zn and/or B in the grain boundary is higher than the inside of the soft magnetic alloy particles, and more preferably, Zn and/or B are substantially Not included in the soft magnetic alloy particles.

Further, the glassy phase containing Zn does not necessarily have to be present to cover the entire surface of the soft magnetic alloy particles, and may be formed on a part of the surface of the soft magnetic alloy particles.

Further, in Fig. 3, for the sake of convenience, the glassy phase 40 containing Zn is shown in the form of particles, but it is not necessarily required to be in the form of particles, for example, It may be formed in a layered manner in the vicinity of the interface between the soft magnetic alloy particles 21 and the grain boundaries 30.

In the present embodiment, the method of determining whether or not the glassy phase containing Zn is present on the surface and the grain boundary of the soft magnetic alloy particles is not particularly limited, and can be determined, for example, by analyzing a mapping image of Zn.

Further, the discrimination between the soft magnetic alloy particles and the grain boundaries can be performed by observing the magnetic core using a scanning transmission electron microscope (STEM). Specifically, the cross section of the dielectric layer is photographed by STEM, and a bright field (BF) image is obtained. In the bright field image, a region existing between the soft magnetic alloy particles and the soft magnetic alloy particles and having a contrast different from that of the soft magnetic alloy particles is used as a grain boundary. Whether or not the judgment has a different contrast can be visually performed, or can be judged by a software that performs image processing or the like.

Further, even if the observation point is determined from an arbitrary cross section of the magnetic core and EDS analysis or EPMA analysis is performed, it is confirmed that the glassy phase containing Zn exists in the grain boundary 30. Further, according to these analyses, it is also possible to confirm the concentration distribution of various components in the interior of the alloy particles or on the surface thereof. Further, according to the STEM analysis, the phase formed on the surface of the alloy particles can be specified even if it is related to amorphous or crystalline.

In the soft magnetic material composition according to the present embodiment, it is also possible to determine whether or not various elements exist in the element (B, Fe, Si, M, etc.) other than Zn by the same method as in the case of the above Zn. The surface of the soft magnetic alloy particles and the grain boundaries. Further, regarding B, it is possible to determine whether or not various elements are present on the surface and grain boundaries of the soft magnetic alloy particles by performing ICP analysis or EPMA analysis.

In the soft magnetic composition according to the embodiment, zinc is used. The content of the (Zn) is preferably 0.05 to 10.0% by mass, and more preferably 0.1 to 5.0% by mass in terms of ZnO, based on the mass% of the soft magnetic alloy 100. By satisfying the above-described range, the magnetic properties (especially the initial magnetic permeability μi) or the electrical resistivity can be favorably maintained in the magnetic core according to the present embodiment, and the moldability (especially the bending strength) can be improved.

In the soft magnetic material composition according to the present embodiment, the content of boron (B) is preferably 0.05 to 10.0% by mass, and more preferably 0.1 to 5.0% by mass in terms of B ₂ O ₃ based on the mass % of the soft magnetic alloy 100. %. By satisfying the above-described range, the magnetic properties (especially the initial magnetic permeability μi) or the electrical resistivity can be favorably maintained in the magnetic core according to the present embodiment, and the moldability (especially the bending strength) can be improved.

In the soft magnetic material composition according to the present embodiment, when a glassy phase containing Zn is not present at the grain boundary, sufficient strength may not be obtained. In addition, the strength tends to increase as the proportion of the glassy phase containing Zn increases, but in the case of too much, the magnetic properties (especially the initial magnetic permeability μi) tend to decrease.

The soft magnetic alloy particles according to the present embodiment are composed of a Fe—Si—M-based soft magnetic alloy or a Fe—Ni—Si—M-based soft magnetic alloy.

Here, the above M is at least one selected from the group consisting of chromium (Cr), aluminum (Al), titanium (Ti), cobalt (Co), and nickel (Ni).

In particular, in the present embodiment, the soft magnetic alloy particles are preferably Fe-Si-Cr soft magnetic alloy, Fe-Si-Al soft magnetic alloy or Fe-Ni-Si-Co soft magnetic alloy, Fe-Ni- The Si-Co-M-based soft magnetic alloy is more preferably an Fe-Si-Cr-based soft magnetic alloy.

By using such soft magnetic alloy particles, the soft magnetic material composition according to the present embodiment can satisfactorily maintain magnetic properties (initial magnetic permeability μi or the like) or electrical resistivity and improve moldability (particularly, bending strength). Further, since it can be molded by a relatively low molding pressure at the time of press molding, it is possible to further reduce the load on the mold and improve the productivity.

In the case where the above-mentioned M is a chromium (Cr), the Fe-Si-Cr-based soft magnetic alloy preferably contains yttrium in an amount of 0.1 to 9% by mass in terms of Si and 0.1 to 15% by mass in terms of Cr. The balance is composed of iron (Fe). In addition, it is preferable to contain 矽 of 1.4 to 9% by mass, and particularly preferably 4.5 to 8.5 % by mass in terms of Si, and further preferably 1.5 to 8 % by mass, particularly preferably 3 to 7 % by mass in terms of Cr. Chromium, preferably the balance is composed of iron (Fe).

In the case where the above-mentioned M is aluminum (Al), the Fe-Si-Al soft magnetic alloy preferably contains yttrium in an amount of 0.1 to 15% by mass in terms of Si and 0.1 to 10% by mass in terms of Al. Aluminum, the balance is composed of iron (Fe).

In the case where the above-mentioned M is a cobalt (Co), it is preferable that the Fe-Ni-Si-Co-based soft magnetic alloy contains yttrium in an amount of 0.1 to 3.0% by mass in terms of Si and 40.0 to 50.0 in terms of Ni. % of nickel, cobalt of 0.1 to 5.0% by mass in terms of Co, and the balance is composed of iron (Fe).

The soft magnetic alloy particles according to the present embodiment preferably have an average crystal grain diameter of 30 to 60 μm. By making the average crystal grain diameter into the above range, it is possible to easily achieve thinning of the magnetic core.

In the soft magnetic material composition according to the present embodiment, an oxide phase including a part of a component constituting the soft magnetic alloy particles may be formed on the surface of the soft magnetic alloy particles 21 (interfacing with the grain boundary 30).

The oxide phase is not particularly limited, and may be an oxide phase containing an element other than oxygen and oxygen, or a composite oxide phase containing two or more elements other than oxygen. In addition, as such an oxide phase and a composite oxide phase, for example, amorphous portions including a part of components constituting the soft magnetic alloy particles are equal.

Further, in the present invention, the oxide phase and the composite oxide phase refer to a broad concept including an amorphous phase, a crystalline phase, and a mixed phase thereof.

Here, in the case where the soft magnetic alloy particles are Fe-Si-Cr-based soft magnetic alloys, the above oxide phase may be a Si-Cr composite oxide phase in which Cr is larger than particles in the soft magnetic alloy particles 21. The Si—Cr composite oxide phase is not particularly limited, and for example, amorphous containing Si and Cr is equivalent.

Further, in the soft magnetic material composition according to the embodiment, the oxide phase may contain a glassy phase containing Zn. Examples of the oxide phase containing the glassy phase containing Zn include an oxide phase in which an amorphous portion and a crystalline substance are mixed, or a component which forms a soft magnetic alloy particle with a component such as Zn contained in a glassy phase. A part of the composite oxide formed by chemical bonding is equal.

Further, in the present embodiment, the oxide phase does not necessarily need to be formed to cover the entire surface of the soft magnetic alloy particles, and may be formed on a part of the surface of the soft magnetic alloy particles. Further, the thickness of the above oxide phase may be non-uniform, and the composition may also be heterogeneous.

In addition, in the surface of the soft magnetic alloy particles according to the present embodiment, the presence or absence of the oxide phase or the thickness thereof may be based on the alloy composition of the soft magnetic alloy particles and the bonding in the method of producing a magnetic core (molded body) to be described later. material The type of the additive or the amount thereof to be added, the other added components, the heat treatment temperature of the molded body, and the atmosphere are controlled.

Further, in the soft magnetic material composition according to the embodiment, the soft magnetic alloy particles 21 may be directly coupled to the adjacent soft magnetic alloy particles 21 via the oxide phase.

The soft magnetic material composition according to the present embodiment may contain components such as carbon (C) and zinc (Zn) in addition to the constituent components of the soft magnetic alloy particles.

Further, C is considered to be derived from an organic compound component used in the production process of the soft magnetic composition. Further, Zn is considered to be derived from zinc stearate added to a mold in order to reduce the pressure of the device when the soft magnetic composition is obtained by powder molding.

The content of carbon (C) in the soft magnetic material composition according to the present embodiment is preferably less than 0.05% by mass, and more preferably from 0.01 to 0.04% by mass. If the content of C is too large, there is a tendency that sufficient strength as a magnetic core cannot be obtained.

Further, the soft magnetic material composition according to the present embodiment may contain unavoidable impurities in addition to the above components.

Further, as another embodiment, it is preferable that Si is further present at the grain boundary of the soft magnetic composition. Thereby, high magnetic characteristics can be maintained and strength can be further improved. In particular, even when molded at a relatively low molding pressure, sufficient strength as a magnetic core can be obtained, so that the burden on the mold is also reduced, and productivity is improved.

In the soft magnetic composition according to the embodiment, Si is It is considered to exist as a grain boundary 30 formed between two particles or a grain boundary 31 (three-phase point or the like) existing between three or more particles as a phase containing Si.

Since the phase containing Si in this manner exists in the grain boundary, the magnetic core according to the present embodiment can obtain sufficient strength as a magnetic core even when molded at a relatively low molding pressure. Further, such a Si-containing phase can function as an insulator by being present at the grain boundary.

The Si-containing phase according to the present embodiment is preferably an Si oxide phase or a Si composite oxide phase. The Si oxide phase and the Si composite oxide phase are not particularly limited, and examples thereof include an amorphous phase containing Si, an amorphous germanium, a cerium oxide, and a Si—M composite oxide.

Further, in the soft magnetic material composition according to the present embodiment, it is preferable that the phase containing Si be further present on the surface of the soft magnetic alloy particles 21 (interfacing with the grain boundary 30).

For example, when the soft magnetic alloy particles are Fe—Si—Cr-based soft magnetic alloys, the Si-containing phase is preferably a Si—Cr composite oxide phase. The Si-Cr composite oxide phase is not particularly limited, but Cr is more than the particles of the soft magnetic alloy particles 21.

The Si-containing phase according to the present embodiment is preferably made of an amorphous material. Further, a part of the crystal may be formed.

The thickness of the Si-containing phase according to the present embodiment is preferably 0.01 to 0.2 μm, and more preferably 0.01 to 0.1 μm.

Further, the phase containing Si does not necessarily have to be formed so as to cover the entire surface of the soft magnetic alloy particles, and may be formed on a part of the surface of the soft magnetic alloy particles. In addition, the thickness of the phase containing Si may be non-uniform, the composition It can also be heterogeneous.

The presence or absence of the Si-containing phase and the thickness thereof according to the present embodiment can be controlled according to the type of the binder in the magnetic core manufacturing method to be described later, the amount thereof to be added, the other additive component, the heat treatment temperature of the molded body, the atmosphere, and the like. .

Next, an example of a method of manufacturing a magnetic core according to the embodiment will be described.

The magnetic core of the present embodiment can be produced by heat-treating a molded body including a soft magnetic alloy powder and a binder (bonding resin). Hereinafter, a preferred method of producing magnetic properties according to the present embodiment will be described in detail.

The production method according to the present embodiment preferably has a step of mixing a soft magnetic alloy powder, a lithium additive, and a binder to obtain a mixture; after drying the mixture to obtain a dried body, the pulverized body is pulverized a step of forming a granulated powder; a step of molding a mixture or a granulated powder into a shape of a powder magnetic core to be produced and obtaining a molded body; and a molded body obtained by heating to harden the adhesive material and obtain a powder magnetic The process of the core.

The magnetic core obtained by the manufacturing method according to the present embodiment can particularly improve the bending strength.

Although the reason for obtaining such an effect is not clear, it can be considered as the mechanism described below.

In the process of heating the molded body, it is considered that by making the crystallized glass a high temperature state and softening in the gap (grain boundary region) of the soft magnetic alloy particles, the bonding between the metal particles becomes firm and the obtained magnetic core The strength is increased.

As a soft magnetic alloy powder, it can be used containing Fe-Si-M A soft magnetic alloy powder of alloy particles composed of a soft magnetic alloy or a Fe-Ni-Si-M soft magnetic alloy.

The shape of the soft magnetic alloy powder is not particularly limited, but is preferably spherical or ellipsoidal from the viewpoint of maintaining inductance up to a high magnetic field region. Among these, from the viewpoint of further increasing the strength of the powder magnetic core, it is preferably an ellipsoidal shape. Further, the soft magnetic alloy powder preferably has an average particle diameter of 10 to 80 μm, more preferably 30 to 60 μm. When the average particle diameter is too small, the magnetic permeability tends to be low, and the magnetic properties of the soft magnetic material tend to decrease, and the operation becomes difficult. On the other hand, if the average particle diameter is too large, there is a tendency that the eddy current loss increases and the abnormal loss increases.

The soft magnetic alloy powder can be obtained by the same method as the preparation method of a known soft magnetic alloy powder. At this time, it can be prepared by an aerosol method, a water mist method, a turntable method, or the like. Among these methods, in order to easily produce a soft magnetic alloy powder having desired magnetic properties, a water mist method is preferred.

Examples of the crystallized glass include borosilicate glass and bismuth glass as such crystallized glass.

The amount of the crystallized glass to be added is preferably 0.1 to 10.0 parts by mass, and more preferably 0.1 to 5.0 parts by mass, based on 100 parts by mass of the soft magnetic alloy powder. By satisfying the above range, the glassy phase can be efficiently formed at the grain boundary of the soft magnetic composition, and the strength of the magnetic core can be improved.

Further, more preferably, the crystallized glass described above contains Zn. By using such a crystallized glass, a glassy phase containing Zn can be efficiently formed at the grain boundary of the obtained soft magnetic composition, and the strength of the magnetic core can be improved and the magnetic properties (especially the initial magnetic permeability μi) can be improved. As such a Zn Examples of the crystallized glass include zinc borosilicate glass and bismuth zinc glass.

Further, the content of Zn in the crystallized glass is preferably 10% by mole or more, more preferably 30 to 70% by mole, still more preferably 30 to 50% by mole.

Further, it is further preferred that the crystallized glass contains boron (B). By using such a crystallized glass, the strength of the magnetic core can be improved and the magnetic properties (especially the initial magnetic permeability μi) can be improved. Examples of such crystallized glass include borosilicate glass and barium borate glass.

Further, the content of B in the crystallized glass is preferably 10% by mole or more, and more preferably 15 to 30% by mole.

As the binder, a known resin can be used, and examples thereof include various organic polymer resins, anthrone resins, phenol resins, epoxy resins, and water glass.

In particular, in the present embodiment, it is preferable to use an adhesive material containing an fluorenone resin as a binder. By using an anthrone as a binder, it is possible to efficiently form a phase containing Si at the grain boundary of the soft magnetic composition. The magnetic core composed of such a soft magnetic composition can exhibit sufficient strength even when molded at a relatively low molding pressure.

In this case, the adhesive material may be used alone or in combination with other adhesive materials. Further, from the viewpoint of preferably limiting the content of carbon (C) in the soft magnetic material composition to less than 0.05% by mass, it is preferable to use a binder mainly composed of an anthrone resin. If the content of C in the soft magnetic composition is too large, the strength of the obtained magnetic core tends to decrease.

The amount of the binder to be added varies depending on the magnetic properties of the magnetic core required, and is preferably 1 to 10 parts by weight, more preferably 100 parts by weight, based on 100 parts by weight of the soft magnetic alloy powder. 3 to 9 parts by weight. When the amount of the binder to be added is too large, the magnetic permeability tends to decrease and the loss tends to increase. On the other hand, if the amount of the binder to be added is too small, it tends to be difficult to ensure insulation.

The amount of the fluorenone resin to be added is preferably 3 to 9 parts by weight based on 100 parts by weight of the soft magnetic alloy powder. When the amount of the fluorenone resin added is too small, it is difficult to form a phase containing Si at the grain boundary of the soft magnetic composition, and the strength of the molded article tends to decrease.

Further, in the above mixture or granulated powder, an organic solvent may be added as needed within a range that does not impair the effects of the present invention.

The organic solvent is not particularly limited as long as it can dissolve the binder, and examples thereof include various solvents such as toluene, isopropyl alcohol, acetone, methyl ethyl ketone, chloroform, and ethyl acetate.

Further, in the above mixture or granulated powder, various additives, lubricants, plasticizers, thixotropic agents and the like may be added as needed within a range not inhibiting the effects of the present invention.

Examples of the lubricant include aluminum stearate, barium stearate, magnesium stearate, calcium stearate, zinc stearate, and barium stearate. These lubricants may be used alone or in combination of two or more. Among these lubricants, zinc stearate is preferably used as the lubricant from the viewpoint of so-called small rebound.

In the case of using a lubricant, the amount thereof is preferably 0.1 to 0.9 parts by mass, more preferably relative to 100 parts by weight of the soft magnetic alloy powder. 100 parts by weight of the soft magnetic alloy powder is 0.3 to 0.7 parts by mass. If the amount of the lubricant is too small, there is a tendency that demolding after molding becomes difficult and molding cracks easily occur. On the other hand, if the lubricant is excessive, the molding density is lowered and the magnetic permeability is decreased.

In particular, when zinc stearate is used as the lubricant, it is preferred to adjust the amount of addition so that the content of zinc (Zn) in the obtained soft magnetic composition is in the range of 0.004 to 0.2% by mass. If the content of Zn is too large, there is a tendency that sufficient strength as a magnetic core cannot be obtained.

The method of obtaining the mixture is not particularly limited, and is obtained by mixing a soft magnetic alloy powder, a binder, and an organic solvent by a conventionally known method. Further, various additive materials can be added as needed.

A mixing machine such as a pressure kneader, an attritor, a vibration pulverizer, a ball mill, a V-type mixer, or a granulator such as a flow granulator or a rotary granulator can be used for mixing.

Further, the temperature and time of the mixing treatment are preferably about 1 to 30 minutes at room temperature.

The method for obtaining the granulated powder is not particularly limited, and is obtained by pulverizing the dried mixture after drying the mixture by a conventionally known method.

The temperature and time for the drying treatment are preferably from room temperature to about 200 ° C for 5 to 60 minutes.

A lubricant may be added to the granulated powder as needed. It is preferred to mix for 5 to 60 minutes after adding the lubricant to the granulated powder.

As a method of obtaining a molded body, there is no particular limitation, and excellent Alternatively, a mixture or a granulated powder is filled into the cavity by a conventionally known method using a molding die having a cavity having a desired shape, and the mixture is compression molded at a prescribed molding temperature and a prescribed molding pressure. .

The molding conditions in the compression molding are not particularly limited, and may be appropriately determined depending on the shape and size of the soft magnetic alloy powder, the shape, size, density, and the like of the powder magnetic core. For example, the maximum pressure is usually about 100 to 1000 MPa, preferably about 400 to 800 MPa, and the maximum pressure holding time is about 0.5 second to about 1 minute.

In addition, when the molding pressure is too low, it is difficult to achieve high density and high magnetic permeability due to molding, and it is difficult to obtain sufficient mechanical strength. On the other hand, if the molding pressure at the time of molding is too high, there is a tendency that the pressure application effect is saturated, and there is a tendency that the manufacturing cost increases and productivity and economy are impaired, and in addition, the molding die tends to be deteriorated and durability. The tendency to decrease.

The molding temperature is not particularly limited, but is usually preferably from room temperature to about 200 °C. Further, the higher the molding temperature at the time of molding, the higher the density of the molded body tends to be. However, if it is too high, the oxidation of the soft magnetic alloy particles is promoted and the performance of the obtained powder magnetic core is deteriorated. In addition, manufacturing costs increase and productivity and economy are impaired.

The method of heat-treating the molded body obtained after molding is not particularly limited as long as it is carried out by a known method. In general, it is preferably molded into an arbitrary shape by molding at a predetermined temperature by using an annealing furnace. The molded body is subjected to heat treatment.

The treatment temperature at the time of heat treatment is not particularly limited, and is usually excellent. It is selected to be about 600 to 900 ° C, more preferably 700 to 850 ° C. When the treatment temperature at the time of heat treatment is too high or too low, there is a sufficient strength that magnetic properties cannot be obtained.

The heat treatment step is preferably carried out in an atmosphere containing oxygen. Here, the atmosphere containing oxygen is not particularly limited, and examples thereof include an atmospheric atmosphere (generally containing 20.95% of oxygen) or a mixed atmosphere of an inert gas such as argon or nitrogen. It is preferably carried out under an atmospheric atmosphere. By performing heat treatment in an atmosphere containing oxygen, a phase containing Si can be efficiently formed at the grain boundary of the soft magnetic composition.

Further, the powder magnetic core thus obtained has a molded body density of preferably 5.50 g/cm ³ or more. When the density of the molded body is 5.50 g/cm ³ or more, the powder magnetic core having a high density tends to be excellent in various properties such as high magnetic permeability, high strength, high core resistance, and low core loss. .

The embodiment of the present invention has been described above, but the present invention is not limited to the embodiment, and it is needless to say that it can be implemented in various forms without departing from the spirit of the invention. .

For example, in the above embodiment, the magnetic core (powder core) is produced by subjecting the mixture or the granulated powder to powder molding, but the magnetic core may be produced by molding the mixture into a sheet shape and laminating. Further, in addition to dry molding, a molded body can be obtained by wet molding, extrusion molding, or the like.

Further, in the above embodiment, the Si-containing phase is formed at the grain boundary of the soft magnetic material composition. Therefore, the fluorenone resin is used as the binder. However, instead of the fluorenone resin, tannin or cerium oxide particles may be used. The Si component serves as an additive.

In addition, the molded body may be coated with glass or Resin impregnation. Thereby, the strength of the magnetic core can be further improved.

Further, in the above-described embodiment, the magnetic core according to the present embodiment is used as a coil type electronic component, but is not particularly limited, and may be suitably used as a motor, a switching power supply, a DC-DC converter, a transformer, or the like. A magnetic core of various electronic components such as a choke coil is used. In particular, it is more suitable as a magnetic core for a DC-DC converter for mobile use.

Further, in the above-described embodiment, the magnetic core is composed of the soft magnetic material composition according to the present invention, but the soft magnetic body composition according to the present invention may constitute the element body of the electronic component or the soft magnetic body composition according to the present invention. Other molded parts.

[Examples]

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited to these examples.

(Example 1) About sample 1 [Modulation of Soft Magnetic Alloy Powder]

First, ingots, chunks (blocks) or pellets (particles) of Fe monomer, Cr monomer, and Si monomer are prepared. Then, they are mixed so as to have a composition of 89.5 % by mass of Fe, 6.5 % by mass of Si, and 4.0% by mass of Cr, and are accommodated in a crucible disposed in the water atomizing device. Next, in a inert atmosphere, a working coil provided outside the crucible is used, and the crucible is heated to 1600 ° C or higher by high frequency induction, and the ingot, block or pellet in the crucible is melted and mixed to obtain a melt.

Next, the melt in the crucible is ejected from the nozzle provided in the crucible, and at the same time, the high-pressure (50 MPa) water flow collides with the melted liquid and the reaction is performed. After cooling, a soft magnetic alloy powder (average particle diameter: 50 μm) composed of Fe—Si—Cr-based particles was produced.

The composition analysis of the obtained soft magnetic alloy powder was carried out by a fluorescent X-ray analysis method, and as a result, it was confirmed that it was consistent with the composition of the feed.

[Production of powder magnetic core]

6 parts by weight of an anthrone resin (manufactured by Toray Dow Corning Organic Co., Ltd., trade name: SR2414LV) was added to 100 parts by weight of the obtained soft magnetic alloy powder, and these were mixed by a pressure kneader at room temperature. minute. Next, the mixture was dried in air at 150 ° C for 20 minutes. 0.5 parts by weight of zinc stearate (Zinc Stearate, manufactured by Nitto Kasei Co., Ltd.) was added as a lubricant to 100 parts by weight of the soft magnetic alloy powder after drying, and mixed by a V-type mixer for 10 minutes.

Next, the obtained mixture was molded into a square sample of 5 mm × 5 mm × 10 mm to prepare a molded body. Further, the molding pressure was 600 MPa. The fluorenone resin was hardened and a powder magnetic core was obtained by heat-treating the pressed molded body at 750 ° C for 60 minutes in the atmosphere.

[various evaluations] <Observation of grain boundaries>

First, the powder core is cut. The cut surface was observed by a scanning transmission electron microscope (STEM), and discrimination between the soft magnetic alloy particles and the grain boundaries was performed.

<3 point bending strength test (breaking strength)>

For the powder magnetic core sample, a 3-point bending strength test was carried out in accordance with JIS R1601. The three-point bending strength is the maximum bending stress (kg/mm ² ) when the test piece is placed on two fulcrums disposed at a certain distance and the load is applied to one point in the center between the fulcrums and is broken.

<Initial Permeability (μi)>

A 10-inch copper wire was wound around a powder magnetic core sample, and an initial magnetic permeability μi was measured using an LCR tester (manufactured by Hewlett Packard, trade name: 4284A). As measurement conditions, the measurement frequency was 1 MHz, the measurement temperature was 23 ° C, and the measurement level was 0.4 A/m.

About sample 2~sample 7

Samples 2 to 7 were added with A (commercially available zinc borosilicate crystallized glass, average particle diameter) in the production of the powder magnetic core with respect to 100 parts by weight of the soft magnetic alloy powder as shown in Table 1. A powder magnetic core sample was produced in the same manner as in Sample 1, except that the thickness was 1.5 μm, the expansion coefficient was 63.0 × 10 ^-7 , the softening temperature was 590 ° C, and the crystallization temperature was 705 ° C. The same evaluation was carried out. The evaluation results are shown in Table 1.

About sample 8~sample 13

Samples 8 to 13 were added with glass B (a commercially available zinc borosilicate crystallized glass in Japan, except for 100 parts by weight of the soft magnetic alloy powder as shown in Table 1 in the production of the powder magnetic core, A powder magnetic core sample was produced in the same manner as in the sample 1, except that the average particle diameter was 4.1 μm, the expansion coefficient was 57.0 × 10 ^-7 , the softening temperature was 661 ° C, and the crystallization temperature was 771 ° C. evaluation of. The evaluation results are shown in Table 1.

About sample 14 to sample 19

Samples 14 to 19 were added with glass C as a value shown in Table 1 in 100 parts by weight of the soft magnetic alloy powder in the production of the powder magnetic core (Japanese commercially available enamel crystallized glass, average particle size) A powder magnetic core sample was produced in the same manner as the sample 1 except that the diameter was 3.2 μm, the expansion coefficient was 67.8 × 10 ^-7 , the softening temperature was 578 ° C, and the crystallization temperature was 731 ° C. The same evaluation was carried out. The evaluation results are shown in Table 1.

Further, the composition of each of the glasses A to C is as follows. The glass A contains 15 to 30% by mass of B ₂ O ₃ , 50 to 70% by mass of ZnO, 5 to 25 % by mass of SiO ₂ , and other components. The glass B contains 15 to 30% by mass of B ₂ O ₃ , 50 to 70% by mass of ZnO, 5 to 25 % by mass of SiO ₂ , and other components. The glass C contains 50 to 60% by mass of Bi ₂ O ₃ , 5 to 20% by mass of B ₂ O ₃ , 10 to 20% by mass of ZnO, 1 to 10% by mass of SiO ₂ , and other components.

In addition, since the bending strength differs depending on the type of the metal or the binder constituting the magnetic core, it is preferably 11.7 kg/mm ² or more in the present embodiment.

The results of STEM observation and EDS analysis were confirmed in sample 2~ In the grain boundary of the sample 19, a glassy phase containing Zn was present, and a glassy phase containing Zn was not present at the grain boundary of the sample 1.

As shown in Table 1, it was confirmed that in the samples 2 to 19 in which the glassy phase containing Zn was present at the grain boundary, the strength was improved as compared with the sample 1 in which the glassy phase containing Zn was not present. It was confirmed that the improvement rate (relative to the increase rate of the sample 1) was as high as about 5 to 30%.

(Example 2) About sample 21~sample 26

Samples 21 to 26 were prepared by using a non-fluorenone resin (manufactured by Nagase ChemteX Corporation, trade name: DENATITE XNR 4338) as a binder resin, and sample 1, sample 2, sample 4, and sample, respectively. 7. The sample of the sample 10 and the sample 16 were prepared in the same manner as the sample 16 and the same evaluation was performed. The evaluation results are shown in Table 2.

Further, since the bending strength differs depending on the kind of the metal or the binder constituting the magnetic core, it is preferably 9.0 kg/mm ² in the present embodiment.

As a result of STEM observation and EDS analysis, it was confirmed that a glassy phase containing Zn exists in the grain boundary of sample 22 to sample 26, and grain boundary of sample 21 exists. There is no glassy phase containing Zn.

As shown in Table 2, in the samples 22 to 26 in which the glassy phase containing Zn was present at the grain boundary, the strength was greatly improved as compared with the sample 21 in which the glassy phase containing Zn was not present. In particular, the rate of improvement (relative to the increase rate of the sample 21) is as high as about 5 to 30%.

Further, as shown in Table 2, Si was not observed in the grain boundaries of Samples 22 to 26. By comparing Table 2 with Table 1, it was confirmed that the flexural strength was improved by substantially observing Si at the grain boundary. Further, in the samples 2 to 19 and the samples 22 to 26, boron (B) at the grain boundary was also observed. This is considered to be because boron (B) is contained in the glasses A, B, and C.

(Example 3) About sample 31~sample 36

In the sample 31 to the sample 36, a soft magnetic alloy powder composed of a composition of 84.7% by mass of Fe, 9.7% by mass of Si, and 5.6% by mass of Al was used as the soft magnetic alloy powder, and the same as in Example 1. Samples 1, Sample 2, Sample 4, Sample 7, Sample 10, and Sample 16 were prepared in the same manner as in Sample 16, and the same evaluation was performed. The evaluation results are shown in Table 3.

About sample 37~ sample 42

In the sample 37 to the sample 42, a soft magnetic alloy powder composed of a composition of 49.2% by mass of Fe, 44.0% by mass of Ni, 2.3% by mass of Si, and 4.5% by mass of Co is used as the soft magnetic alloy powder. A powder magnetic core sample was produced in the same manner as in Sample 1, Sample 2, Sample 4, Sample 7, Sample 10, and Sample 16 of Example 1, and the same evaluation was performed. The evaluation results are shown in Table 3.

Further, since the bending strength differs depending on the type of the metal or the bonding material constituting the magnetic core, in the present embodiment, in the case of a magnetic core composed of a Fe-Si-Al soft magnetic alloy, The flexural strength is preferably 6.9 kg/mm ² or more, and in the case of a magnetic core composed of a Fe—Ni—Si—Co-based soft magnetic alloy, the flexural strength is preferably 11.0 kg/mm ² or more.

As a result of STEM observation and EDS analysis, it was confirmed that a glassy phase containing Zn exists in the grain boundaries of sample 32 to sample 36 and sample 38 to sample 42, and the grain boundary of sample 31 and sample 37 does not exist. Glassy phase of Zn.

As shown in Table 3, in the sample 32 to the sample 36 and the sample 38 to the sample 42 in which the glassy phase containing Zn was present at the grain boundary, the sample 31 in which the glassy phase containing Zn was not present and Compared with the sample 37, the strength was improved.

(Example 4)

In addition, it was confirmed that Fe-Ni-Si-Cr soft magnetic alloy, Fe-Ni-Si-Al soft magnetic alloy, Fe-Si-Ti soft magnetic alloy, Fe-Ni-Si-Ti soft magnetic alloy, When Fe-Si-Co soft magnetic alloy and Fe-Si-Ni soft magnetic alloy were used as alloy types, the same tendency as in Examples 1 to 3 was obtained.

From these results, it was confirmed that according to the present invention, the strength can be improved even when the type of the alloy constituting the soft magnetic alloy composition is changed.

Claims (7)

A soft magnetic body composition is a soft magnetic body composition having a plurality of soft magnetic alloy particles and a grain boundary existing between the soft magnetic alloy particles, wherein the soft magnetic alloy particles are made of Fe-Si- M-based soft magnetic alloy or Fe-Ni-Si-M-based soft magnetic alloy, wherein M is at least one selected from the group consisting of Cr, Al, Ti, Co, and Ni, and Zn is present at the grain boundary. Glassy phase. The soft magnetic composition according to claim 1, wherein Si is further present at the grain boundary. The soft magnetic composition according to claim 1 or 2, wherein B is further present in the grain boundary. A method for producing a soft magnetic body composition, comprising: a step of mixing a soft magnetic alloy powder, a crystallized glass, and a binder to obtain a mixture; a step of molding the mixture to obtain a molded body; and heating the molding The process of the body. A soft magnetic composition obtained by the production method described in claim 4 of the patent application. A magnetic core comprising the soft magnetic composition according to any one of claims 1 to 3 and 5. A coil type electronic component characterized by having the magnetic core described in claim 6 of the patent application.