KR102258927B1 - Manufacturing method of magnetic material - Google Patents

Abstract

A magnetic material of the present invention comprises: a soft magnetic material coarse grain powder with the grain size range of 10-40㎛; a Fe small powder with the grain size range of 1-5㎛; and a mixed powder of an Fe nano powder with the grain size range of 30-200㎚ having a silane compound coating layer formed on the surface, wherein the Fe nano powder having a silane compound coating layer formed on the surface undergoes an aging process. Here, the Fe nano powder undergoes an aging process at a low temperature for a long period of time after the silane compound coating layer is formed on the surface to form a uniform surface, thereby having a uniform and reinforced coupling with an epoxy binder which is added afterward for formability. Furthermore, dispersing and viscoelastic properties between powders can be increased such that the Fe nano powder may be more effectively inserted to fill an empty space between the soft magnetic material coarse grain powder and the Fe small powder, thereby significantly increasing the packing density and magnetic permeability of a final magnetic material. Therefore, the magnetic material powder according to the present invention provides a great advantage for the production of an ultrathin-type flexible power inductor having electrical characteristics with high magnetic permeability.

Description

Manufacturing method of magnetic body {MANUFACTURING METHOD OF MAGNETIC MATERIAL}

The present invention relates to a method of manufacturing a magnetic material, and in particular, to a method of manufacturing a magnetic material suitable for manufacturing a power inductor having an excellent magnetic permeability of a flexible ultra-thin type due to improved filling density and permeability.

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In accordance with the recent trend of slimmer portable devices such as smart phones, it is required to use a multilayered inductor as a multilayered chip component capable of miniaturization and high integration. The multilayer inductor has a relatively large change in the inductance value according to the application of current compared to the wound inductor, but can be miniaturized, so that not only the portable device can be slimmed, but also the consumption of the battery can be minimized.

In general, since the multilayer inductor is manufactured as a bulk or thin film type magnetic material, the electrical properties of the inductor are entirely dependent on the physical properties of the magnetic material forming the inductor. The soft magnetic powder constituting the magnetic body includes ferritic and metallic magnetic powders.

As a ferritic soft magnetic material, there is generally a Ni-Zn ferritic composition, and the electrical resistivity is very high (about 10 ² ~ 10 ¹⁰ Ω·cm) and the eddy current is very low, so it is mainly used as an inductor material. However, due to the low saturation magnetization value, not only does it self-saturate easily at a low current, and thus exhibits poor DC bias characteristics, which leads to a large decrease in inductance, as well as poor DC superposition characteristics, so that the usable current range for a multilayer inductor is small.

On the other hand, metal soft magnetic materials generally include Fe-based, Fe-Ni composition, Fe-Cr composition, and Fe-Si composition, and unlike the ferritic soft magnetic material, they have low coercivity, resulting in low hysteresis loss and high stability at high currents. Therefore, it is suitable as a power inductor with low loss and high current characteristics.

In general, magnetic powder is mixed with a binder and a dispersant, and then compacted to form a bulk, or tape-casting to form and laminate thick film sheets, and heat-treated and fired to form a multilayer inductor. Particularly, the Fe-Si powder composition has excellent soft magnetic properties and thus attracts attention as a high frequency inductor material. However, due to the brittle nature of Si, cracks are easily generated inside the magnetic body during manufacture, and it shows low molding density, so that mechanical strength is low, and electrical properties of high loss and low permeability are exhibited, and thus improvement is required.

1. Unexamined Patent Publication No. 10-2004-0047452 (published on June 5, 2004) 2. Unexamined Patent Publication No. 10-2013-0014848 (published on Feb. 12, 2013) 3. Unexamined Patent Publication No. 10-2002-0064713 (published on Aug. 9, 2002)

Accordingly, an object of the present invention is to provide a method of manufacturing a magnetic material suitable for manufacturing a power inductor having an excellent magnetic permeability of a flexible ultra-thin type with improved filling density and permeability.

The magnetic material according to one aspect of the present invention for solving the above problems includes a coarse soft magnetic material powder in a particle size range of 10 to 40 μm, an Fe fine particle powder in a particle size range of 1 to 5 μm, and a silane-based compound coating film formed on the surface. It includes a mixed powder of Fe nano-powder in a particle size range of 30 to 200 nm including

In addition, optionally, a ratio of the content of the soft magnetic coarse powder (xwt%): the content of the Fe fine powder (ywt%) may be 6≦x<10:0<y≦4.

In addition, optionally, the content of the Fe nano-powder may be 0.1 to 10 wt% based on the total amount of the mixed powder.

In addition, optionally, the composition of the soft magnetic coarse powder is Fe-Ni, Fe-Cr, Fe-Si, Zr-Al-Ni, Zr-Al-Cu, Zr-Al-Ni-Cu, Zr-Ti-Al -Ni-Cu, Zr-Ga-Ni, Ln-Al-Ni, Ln-Al-Cu, Ln-Al-Ni-Cu, Ln-Ga-Ni, Ln-Ga-Cu, Fe-Zr-B, Fe -Hf-B, Fe-Zr-Hf-B, Fe-Co-Ln-B, Co-Zr-Nb-B, Fe-(Al,Ga)-metalloid, Mg-Ln-Ni, Mg It may be at least one selected from the group consisting of -Ln-Cu, Zr-Ti-Be-Ni-Cu, Pd-Ni-P, Pd-Cu-Ni-P, and Pt-Ni-P.

In addition, optionally, the composition of the soft magnetic coarse powder may be Fe-Si and the content of Si may be 3.5 to 6.5 wt% based on the Fe content.

In addition, optionally, the thickness of the silane-based compound coating film may be in the range of 0.5 to 5 nm.

And, a method of manufacturing a magnetic material according to another aspect of the present invention includes the following steps:

-Forming a silane-based compound coating film on the surface of the Fe nano-powder by surface-treating the Fe nano-powder in a particle size range of 30 to 200 nm with a silane solution, followed by aging treatment;

-Preparing a mixed powder by mixing coarse soft magnetic powder in a particle size range of 10 to 40 µm, fine Fe powder in a particle size range of 1 to 5 µm, and Fe nano-powder subjected to aging treatment by forming the silane-based compound coating film; and ;

-Preparing a magnetic slurry by adding an epoxy binder to the mixed powder;

Tape-casting the magnetic material slurry to produce a magnetic material sheet.

And, a method of manufacturing a magnetic material according to another aspect of the present invention includes the following steps:

-Forming a silane-based compound coating film on the surface of the Fe nano-powder by surface-treating the Fe nano-powder in a particle size range of 30 to 200 nm with a silane solution, followed by aging treatment;

-Preparing a mixed powder by mixing coarse soft magnetic powder in a particle size range of 10 to 40 µm, fine Fe powder in a particle size range of 1 to 5 µm, and Fe nano-powder subjected to aging treatment by forming the silane-based compound coating film; and ;

-Preparing a bulk magnetic body by adding an epoxy binder to the mixed powder and applying a molding pressure.

In addition, optionally, the step of aging treatment may be performed in a temperature range of 1 to 10°C.

Also, optionally, the aging process may be performed within a range of 1 to 72 hours.

In addition, optionally, the content of the Fe nano-powder subjected to the aging treatment by forming the silane-based compound coating film may be adjusted to 0.1 to 10 wt% based on the total amount of the mixed powder.

In addition, optionally, the composition of the soft magnetic coarse powder is Fe-Ni, Fe-Cr, Fe-Si, Zr-Al-Ni, Zr-Al-Cu, Zr-Al-Ni-Cu, Zr-Ti-Al -Ni-Cu, Zr-Ga-Ni, Ln-Al-Ni, Ln-Al-Cu, Ln-Al-Ni-Cu, Ln-Ga-Ni, Ln-Ga-Cu, Fe-Zr-B, Fe -Hf-B, Fe-Zr-Hf-B, Fe-Co-Ln-B, Co-Zr-Nb-B, Fe-(Al,Ga)-metalloid, Mg-Ln-Ni, Mg -Ln-Cu, Zr-Ti-Be-Ni-Cu, Pd-Ni-P, Pd-Cu-Ni-P, and one or more may be selected from the group consisting of Pt-Ni-P.

In addition, optionally, the composition of the soft magnetic coarse powder is Fe-Si, wherein the content of Si may range from 3.5 to 6.5 wt% of the Fe content.

In addition, optionally, the silane solution is prepared by dissolving a silane coupling agent in a solvent, and the solvent is water (H ₂ O), ethanol (C ₂ H ₅ OH), methanol (CH ₃ OH), methyl ethyl ketone ( CH ₃ COC ₂ H ₅ ) and benzene (C ₆ H ₆ ) It may be one or more selected from the group including.

In addition, optionally, the silane coupling agent is 3-glycid oxypropyl trimethoxysilane, 3-glycid oxypropyl triethoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane, 3-aminopropyl trimethoxysilane. Oxysilane, 3-aminopropyl triethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryl oxypropyl triethoxysilane, 3-mercaptopropyl trimethoxysilane, vinylethoxysilane, vinyl -Tolyl(2-methoxy-ethoxy)silane, γ-methacryloxypropyl trimethoxysilane, γ-aminopropyl trimethoxysilane, γ-aminopropyl triethoxysilane, N-phenyl-γ-aminopropyl Trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl triethoxysilane, N-phenyl-γ-aminopropyl tri Methoxysilane, β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, γ-glycidoxypropyl trimethoxysilane, and γ-mercaptopropyl trimethoxysilane. have.

In addition, optionally, the amount of the silane solution may be adjusted in the range of 0.05 to 5 wt% relative to the total amount of the Fe nano powder.

In addition, optionally, the step of preparing the magnetic material slurry may include further adding a dispersant to the mixed powder.

In addition, optionally, the molding pressure may be applied in the range ^{of 1.8 to 6.25 ton/cm 2.}

In addition, the method of manufacturing a magnetic material according to another aspect of the present invention is a soft magnetic coarse powder in a particle size range of 10 to 40 μm, a fine Fe powder in a particle size range of 1 to 5 μm, and a nano powder of Fe in a particle size range of 30 to 200 nm. Preparing a mixed powder of, and adding an epoxy binder to the mixed powder to prepare a magnetic body filled with the mixed powder, wherein the Fe nano-powder is surfaced with a silane solution in advance to increase bonding with the epoxy binder. After treatment to form a silane-based compound coating film on the surface of the Fe nano-powder, the aging treatment is performed at a temperature range of 1 to 10°C.

The magnetic powder prepared according to the present invention has a uniform and reinforced bond with an epoxy binder added for later moldability, and increases dispersibility and viscoelasticity between the powders, so that the Fe nano powder is formed between the soft magnetic coarse powder and the Fe fine powder. By making it more effective to pinch and fill empty spaces, the filling density and permeability of the finally manufactured magnetic material are greatly increased. These magnetic powders are ultra-thin and are very advantageous in manufacturing a power inductor having high electrical permeability while having flexibility.

1 is a schematic diagram illustrating a mechanism for forming a silane-based compound coating film through a hydrolysis and dehydration condensation reaction of a silane coupling agent on the surface of an Fe nanopowder according to the present invention through steps (i) to (iii) in turn.
FIG. 2 is a diagram showing uniform and strong bonding properties between a silane-based compound coating film formed on the surface of Fe nano-powder particles in step (iii) of FIG. 1 and an epoxy binder added for later molding according to the present invention, (a) Shows the bonding state of the silane-based compound coating film and the epoxy binder, (b) shows the Fe nano-powder particles adsorbed with the epoxy binder, and (c) shows the enlarged view of the broken line in (a).
3 is an electron micrograph of each powder used according to an embodiment of the present invention, where (a) is an Fe-6.5Si soft magnetic coarse powder having a particle diameter of approximately 40 μm, and (b) is an Fe having a particle diameter of approximately 3 μm. Fine powder, (c) shows Fe nano-powder (before coating with a silane solution) having a particle diameter of approximately 100 nm, respectively.
FIG. 4 is an electron micrograph of a bulk magnetic material made of a mixed powder of a coarse Fe-6.5Si soft magnetic material having a particle diameter of about 40 μm and a fine Fe powder having a particle size of about 3 μm according to an embodiment of the present invention, (a) ~(l) shows the microstructure according to the mixing ratio of the coarse soft magnetic powder and the fine Fe powder and the size of the molding pressure.
FIG. 5 is a volume fraction of a bulk magnetic material according to a mixing ratio of a coarse Fe-6.5Si soft magnetic material having a particle diameter of about 40 μm and a fine Fe powder having a particle size of about 3 μm and a molding pressure according to an embodiment of the present invention. A plot of the change between the permeability (Macroscopic relative permeability: μ') is shown. In addition, the solid line represents the theoretical value of the Ollendorf equation (Equation 1), and the broken line represents the actual value considering the actual half magnetic field value.
6 is an electron micrograph of Fe nano-powder having a particle diameter of about 100 nm used according to an embodiment of the present invention, (a) is before surface treatment with a silane solution, (b) and (c) is a silane It shows each one in the state of surface treatment with a solution.
FIG. 7 shows a plot of changes between the filling rate (Volume fraction) and the magnetic permeability (Macroscopic relative permeability: μ') of the bulk magnetic material prepared with the powder composition of SPL1, SPL3, and SPL4 in Table 2 according to an embodiment of the present invention, and additionally The broken line represents the actual value in consideration of the actual half magnetic field value of the Ollendorf equation (Equation 1) described above.
8 is a shape and electron micrograph of a magnetic sheet formed using the powder composition of Table 2 according to an embodiment of the present invention, (a) is the SPL1 powder composition of Table 2, (b) is the SPL2 powder of Table 2 Composition, (c) shows each magnetic sheet made of the SPL4 powder composition of Table 2.
9 is a shape and electron micrograph of a magnetic sheet formed using the powder composition of Table 2 according to an embodiment of the present invention, (a) is the SPL1 powder composition of Table 2, (b) is the SPL3 powder of Table 2 Compositions, (c) and (d) are electron micrographs of each magnetic sheet prepared with the SPL4 powder composition shown in Table 2.
10A is a graph showing the change in the volume fraction according to the powder composition of the magnetic sheet prepared with the powder composition of Table 3 according to an embodiment of the present invention, and FIG. 10B is a magnetic sheet prepared with the powder composition of Table 3 It is a graph showing the change in macroscopic relative permeability with respect to the change in the filling rate of, and the added broken line represents the actual value in consideration of the actual half magnetic field value of the Ollendorf equation (Equation 1) described above.

)과 자성체의 투자율(μ)은 아래의 Ollendorf 방정식(식 1)에 보이듯이 상호 비례 관계이다.In general, the filling rate of the soft magnetic powder in the magnetic body formed by filling the soft magnetic powder (

) And the magnetic permeability (μ) are mutually proportional as shown in the Ollendorf equation (Equation 1) below.

(식 1)

(Equation 1)

At this time,

μ: permeability;

： 충진율(volume packing fraction);

： Volume packing fraction;

N: anti-magnetic field (diamagnetic field) coefficient (0≤ N ≤1);

μ _m: specific magnetic permeability (intrinsic permeability) of the material (bulk); ego

μ ₀ = 4π×10 ^-7 H/m.

Generally, soft magnetic powders used to form magnetic materials are composed of coarse powders having a particle size in the range of about 50 to 100 μm, so when the magnetic material is manufactured by filling these coarse powders, a lot of empty spaces are formed between these powders. Due to these empty spaces, the total permeability of the magnetic material is lowered. Therefore, when the magnetic body is formed by mixing the coarse powder and the relatively small-sized fine powder, the fine powder inside the magnetic body effectively fills the empty space between the coarse powders and improves the filling rate. This leads to an improvement in permeability.

The composition according to the present invention is composed of a soft magnetic coarse powder mixed with Fe powder, which is a main component that exhibits magnetism of a magnetic material, wherein the Fe powder is composed of a mixture of Fe fine powder and Fe nano powder.

In the composition of the present invention, the Fe fine powder and the Fe nano-powder fill the empty spaces between the soft magnetic coarse powders, and the Fe nano-powder sequentially fills the empty spaces between the Fe fine powders. This drastically increases, and the magnetic permeability of the magnetic body is greatly improved by increasing the content of the Fe powder exhibiting magnetism.

In one embodiment of the present invention, the particle diameter of the soft magnetic coarse powder is in the range of about 10 to 40 μm, preferably in the range of about 20 to 40 μm. In addition, the particle diameter of the Fe fine powder is in the range of about 1 to 5 μm, preferably in the range of about 1.8 to 3 μm. In addition, the particle diameter of the Fe nano-powder is in the range of about 30 to 200 nm, preferably in the range of about 70 to 100 nm.

However, since the Fe nano-powder contained in the composition of the present invention has a very high specific surface area, the frictional force between the powders is greatly increased during manufacturing, so that even if a high pressure is applied during molding, a certain level (e.g., 70% or more) It is difficult to obtain density. This phenomenon is difficult to improve with the current binding system even when a very large amount of binder (eg, about 5 to 6 times or more) is added compared to the existing one. As a result, such poor relative density lowers the saturation magnetic flux density of the formed magnetic material and is easily self-saturated even at a low current, resulting in poor DC bias characteristics with a large decrease in inductance. This is observed as a comparative example to the examples of the present invention described later.

In order to solve this problem, in particular, according to the present invention, the Fe nano-powder contained in the composition of the present invention is surface-treated with a silane coupling agent so that the surface is coated with a silane-based compound. In the present invention, the silane solution in which the silane coupling agent is dissolved in a solvent is hydrolyzed to generate a silanol group (Si-OH) having excellent reactivity, which is hydrogen-bonded with a hydroxyl group (-OH) on the surface of the Fe nanopowder. To form a coating film of the system compound. And, in particular, since such a silane-based compound coating film is formed with a non-uniform thickness through the rapid reaction as described above, the silane-based compound coating film is then aged for a long time (about 1 to 72 hours) at a low temperature (approximately 1 to 10°C). (aging) treatment proceeds a dehydration condensation reaction and forms a covalent bond with the surface of the Fe nano-powder via oxygen.

1 is a schematic diagram illustrating a mechanism for forming a silane-based compound coating film through a hydrolysis and dehydration condensation reaction of a silane coupling agent on the surface of an Fe nanopowder according to the present invention as described above over steps (i) to (iii). to be.

In addition, FIG. 2 is a diagram showing uniform and strong bonding properties between the silane-based compound coating film formed on the surface of the Fe nano-powder particles in step (iii) of FIG. 1 and the epoxy binder added for later molding, (a) The bonding state of the system compound coating film and the epoxy binder is shown, (b) shows the Fe nano-powder particles adsorbed with the epoxy binder, and (c) shows the enlarged view of the broken line portion of (a).

Referring to FIG. 1 and describing in more detail, first, as a starting material, a silane coupling agent is dissolved in a solvent, so that the alkoxy group (Si-OR) of the silane coupling agent is hydrolyzed by water (H ₂ O) to form a siloxane bond (- A silane solution in which Si-O-Si-) is generated is applied to the "Fe nano powder particle surface"("(i)" in FIG. 1). In one embodiment, the coating may be performed by immersing the Fe nano-powder in the silane solution.

In addition, in one embodiment of the present invention, the silane coupling agent is 3-glycid oxypropyl trimethoxysilane, 3-glycid oxypropyl triethoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane, 3 -Aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryl oxypropyl triethoxysilane, 3-mercaptopropyl trimethoxysilane, vinyl Ethoxysilane, vinyl-tolyl (2-methoxy-ethoxy) silane, γ-methacryloxypropyl trimethoxysilane, γ-aminopropyl trimethoxysilane, γ-aminopropyl triethoxysilane, N-phenyl -γ-aminopropyl trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl triethoxysilane, N-phenyl- In the group consisting of γ-aminopropyl trimethoxysilane, β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, γ-glycidoxypropyl trimethoxysilane, and γ-mercaptopropyl trimethoxysilane More than one can be selected.

In addition, in one embodiment of the present invention, the solvent of the silane coupling agent is water (H ₂ O), ethanol (C ₂ H ₅ OH), methanol (CH ₃ OH), methyl ethyl ketone (CH ₃ COC ₂ H ₅ ) and benzene (C ₆ H ₆ ), but one or more solvents selected from the group including, may be used, but the present invention is not limited thereto.

Then, the hydroxyl group (-OH) of the "Fe nano-powder particle surface" and the silanol group (Si-OH) of the siloxane compound are self-assembled to form a silane-based compound coating film in which hydrogen bonds are formed ("(ii )").

And, in order to surface-treat the silane-based compound coating film formed unevenly through a rapid reaction, it is aged for a long time in the range of about 1 ~ 72 at a low temperature in the range of about 1 ~ 10 ℃, and the dehydration condensation reaction proceeds to make a uniform surface layer. To form ("(iii)" in FIG. 1). In one embodiment, the thickness of the finally formed silane-based compound coating film is in the range of about 0.5 to 5 nm, preferably 5 nm.

In particular, in the present invention, as shown in Fig. 2, the silane-based compound coating film 20 formed on the surface of the Fe nano-powder particles 10 is uniform with the epoxy binder 30 added to the mixed powder for later molding. It has strong binding properties. As a result, the epoxy binder is uniformly adsorbed to the Fe nano-powder with a large specific surface area during molding, thereby reducing frictional force between the powders, and increasing dispersibility and viscoelasticity between the powders, so that the Fe nano-powder is the soft magnetic coarse powder. It makes it possible to more effectively squeeze and fill the empty space between the and Fe fine powder. Accordingly, the filling density of the magnetic powder is improved and the magnetic permeability is improved.

In the present invention, the soft magnetic coarse powder composition may be any known soft magnetic material. In one embodiment of the present invention, the soft magnetic coarse powder composition is Fe-Ni, Fe-Cr, Fe-Si, Zr-Al-Ni, Zr-Al-Cu, Zr-Al-Ni-Cu, Zr-Ti -Al-Ni-Cu, Zr-Ga-Ni, Ln-Al-Ni, Ln-Al-Cu, Ln-Al-Ni-Cu, Ln-Ga-Ni, Ln-Ga-Cu, Fe-Zr-B , Fe-Hf-B, Fe-Zr-Hf-B, Fe-Co-Ln-B, Co-Zr-Nb-B, Fe-(Al,Ga)-metalloid, Mg-Ln-Ni , Mg-Ln-Cu, Zr-Ti-Be-Ni-Cu, Pd-Ni-P, Pd-Cu-Ni-P and Pt-Ni-P. In one embodiment of the present invention, the soft magnetic coarse powder composition is preferably Fe-Si powder composition, more preferably Fe-Si powder composition, but the content of Si is 3.5 to 6.5 wt% relative to the Fe content, Most preferably, the composition is Fe-Si powder, but the content of Si is 6.5wt% based on the Fe content.

In addition, in an embodiment of the present invention, the ratio of the content of the soft magnetic coarse powder (xwt%): the content of the Fe fine powder (ywt%) is approximately 6≤x<10:0<y≤4.

In addition, in one embodiment of the present invention, the content of the Fe nano-powder is 0.1 to 10 wt% based on the total amount of the mixed powder in which the soft magnetic coarse powder, Fe fine powder, and Fe nano powder are mixed, and most preferably 0.5 wt%. In one embodiment, when the content of the Fe nano-powder was 0.5 wt%, the highest filling rate and permeability were exhibited, and in particular, aggregation of the nano-powder was somewhat observed when the content was higher than that. In addition, the most preferable particle diameter of the Fe nano-powder is approximately 100 nm.

In addition, in a preferred embodiment of the present invention, the amount of the silane solution for surface treatment of the Fe nano powder is in the range of 0.05 to 5 wt %, and most preferably 0.1 wt %, based on the total amount of the Fe nano powder.

In addition, in a preferred embodiment of the present invention, the aging step of the Fe nano-powder surface-treated with the silane solution is in a temperature range of approximately 1 to 10°C, most preferably at a low temperature of 3°C, in a range of approximately 1 to 72 hours. Proceeds for a long time.

The preferred embodiments of the present invention as described above will be described in detail below. However, the embodiments described below by the present invention are provided to aid in an overall understanding of the present invention, and the present invention is not limited to the following examples.

Example

First, a soft magnetic coarse powder with a particle diameter of about 40 μm and a fine powder of Fe with a particle diameter of about 3 μm made of an Fe-6.5Si composition powder with a Si content of 6.5 wt% relative to the Fe content in the range of 7:3-10:0 The mixture was mixed at a ratio (wt%) to prepare a first mixed powder. On the other hand, after surface treatment of Fe nano-powder having a particle diameter of approximately 100 nm with a silane solution, low-temperature aging treatment at 3° C. for 24 hours, and 0.5 wt% of the total amount of the first mixed powder to the first mixed powder of the Fe nano-powder It was kneaded in the content of. The kneading was carried out under conditions of 1 hour at 50 RPM using a pre-mixer. Then, a magnetic slurry was prepared by adding 3.5 wt% epoxy binder, 1 wt% dispersant, and 6.5 wt% ethanol to the kneaded powder. The prepared slurry was dispersed and mixed under conditions of 3 minutes at a frequency of 64 Hz using a resonance acoustic mixer. The prepared magnetic material slurry was tape-casted with a doctor blade to prepare a magnetic material sheet.

In addition, in order to accurately measure the optimum mixing ratio, filling rate and electromagnetic properties between the powders in the magnetic body, a toroidal type bulk magnetic body was fabricated using the mixed powder. The toroidal has an outer diameter of 30 mm, an inner diameter of 20 mm, and a thickness of 10 mm. To form it, the epoxy binder was added to the kneaded powder and a molding pressure was applied, but the molding pressure was 1.8 to 6.25 ton/cm ² I did. Each of the manufactured toroidal was subjected to microstructure analysis with an electron microscope (SEM), and the density and filling rate were evaluated using an Archimedes scale, respectively. Thereafter, a magnetic sheet was made at an optimal mixing ratio of 7:2.5:0.5 (wt%) of the soft magnetic coarse powder: the Fe fine powder: the Fe nano powder to evaluate the filling rate and the physical properties of the sheet.

In addition, the silane solution for the surface treatment of the Fe nano powder was prepared by using an epoxy-based silane coupling agent (Shinetsu Co., Ltd.) in a mixing ratio of 4:1 with distilled water.

First, FIG. 3 is an electron micrograph of each powder used in this example, where (a) is an Fe-6.5Si soft magnetic coarse powder having a particle diameter of about 40 μm, and (b) is a fine Fe powder having a particle size of about 3 μm. , (C) shows Fe nano-powder (before coating with a silane solution) having a particle diameter of approximately 100 nm, respectively. 3A, a lot of empty spaces are generated between the coarse powders, so a low filling rate is observed, and these empty spaces lower the magnetic permeability.

On the other hand, Table 1 below shows the volume fraction and permeability (Volume fraction) and permeability (Volume fraction) of approximately 40㎛ particle diameter Fe-6.5Si soft magnetic coarse powder and Fe fine particle powder approximately 3㎛ particle diameter according to the size of the mixing ratio ( μ') of change data is shown.

In addition, in connection with Table 1, (a) to (l) of Fig. 4 show the mixing ratio and molding pressure of the coarse Fe-6.5Si soft magnetic material powder of approximately 40 μm particle diameter and the Fe fine particle powder of approximately 3 μm particle diameter, respectively. The electron micrograph of the bulk magnetic material according to the pressure is shown.

And, in connection with Table 1, FIG. 5 shows the filling ratio of the bulk magnetic material according to the mixing ratio of the coarse Fe-6.5Si soft magnetic material powder having a particle diameter of about 40 μm and the fine Fe powder having a particle size of about 3 μm and the size of the molding pressure (Volume fraction) and A plot of the change between the permeability (Macroscopic relative permeability: μ') is shown. In addition, the solid line represents the theoretical value of the Ollendorf equation (Equation 1), and the broken line represents the actual value considering the actual half magnetic field value.

Referring to Table 1, as the content of the Fe fine powder increases and as the molding pressure increases, the filling rate and permeability of the magnetic material increase, which is also confirmed in FIGS. 4 to 5, respectively. In particular, a high permeability was observed in the composition where the mixing ratio of the Fe-6.5Si soft magnetic coarse powder and the Fe fine powder was 7:3, and this was observed while the relatively small-sized fine powder effectively filled the voids between the coarse powders. This is because the filling rate has improved. In addition, referring to FIG. 5, unlike a magnetic body containing no Fe fine powder, a magnetic body containing Fe fine powder follows the trend in consideration of the actual half magnetic field value of the Ollendorf equation (Equation 1), and has a high correlation. Able to know.

On the other hand, Figure 6 is an electron micrograph of the Fe nano-powder having a particle diameter of about 100 nm used in this example, (a) is before surface treatment with a silane solution, (b) and (c) is a silane solution. Each of the surface-treated ones is shown. Referring to (b) and (c) of Figure 6, it is confirmed that a silane compound coating layer having a thickness of about 5 nm was formed on the surface of the Fe nano-powder.

In addition, Table 2 below shows the change data of the volume fraction and the permeability (μ') of the bulk magnetic material of each of the following compositions.

At this time, the SPL1 ~ SPL4 powder composition in Table 2 is as follows:

-SPL1: a powder composition obtained by mixing a coarse Fe-6.5Si soft magnetic body powder having a particle diameter of approximately 40 μm and a fine particle Fe powder having a particle diameter of approximately 3 μm;

-SPL2: a powder composition in which the Fe-6.5Si soft magnetic coarse powder, the Fe fine powder, and Fe nano-powder having a particle diameter of about 100 nm not surface-treated with a silane solution are mixed;

-SPL3: a powder composition of the Fe-6.5Si soft magnetic coarse powder, the Fe fine powder, and the Fe nano-powder surface-treated with a silane solution; And

-SPL4: A powder composition obtained by mixing the Fe-6.5Si soft magnetic coarse powder, the Fe fine powder, and the Fe nano-powder subjected to aging treatment at a low temperature of 3° C. for 24 hours after surface treatment with a silane solution.

In addition, in connection with Table 2, FIG. 7 shows a plot of change between the filling rate (Volume fraction) and the magnetic permeability (Macroscopic relative permeability: μ') of the bulk magnetic body prepared with the powder composition of SPL1, SPL3, and SPL4 of Table 2, and additionally The broken line represents the actual value in consideration of the actual half magnetic field value of the Ollendorf equation (Equation 1) described above.

In particular, referring to Table 2, in the case of the SPL2 powder composition to which Fe nano-powder was added without surface treatment with a silane solution, as described above, due to its very high specific surface area, the frictional force during molding increased significantly and cracked in the manufactured bulk magnetic body. Due to the occurrence of a large number of cracks, it was impossible to measure the permeability and filling rate.

On the other hand, referring to Table 2 and FIG. 7, the composition of the SPL3 powder to which Fe nano-powder was surface-treated with a silane solution was added, the filling rate was improved by 3.5% and the magnetic permeability was slightly improved. It is confirmed that the composition of the SPL4 powder containing the aging-treated Fe nano-powder has improved the filling rate by 6.6% and the permeability by 10%. As described above, the silane-based compound coating film formed on the surface of the particles by surface treatment of the Fe nano-powder has strong binding properties with the epoxy binder added to the mixed powder for later molding. In particular, the silane-based compound coating film formed forms a uniform surface by aging treatment at a low temperature for a long time, which induces a uniform and reinforced bond with the epoxy binder. The uniform and reinforced bonding with this epoxy binder further increases the dispersibility and viscoelasticity between the powders so that the Fe nanopowder can more effectively penetrate and fill the empty space between the soft magnetic coarse powder and the Fe fine powder. Increase filling density and permeability.

Meanwhile, FIGS. 8 and 9 are photographs of a shape and an electron microscope of a magnetic sheet formed using the powder composition of Table 2. In FIG. 8, (a) shows the SPL1 powder composition of Table 2, (b) shows the SPL2 powder composition of Table 2, and (c) shows each magnetic sheet prepared with the SPL4 powder composition of Table 2. And, in Figure 9 (a) is the SPL1 powder composition of Table 2, (b) is the SPL3 powder composition of Table 2, (c) and (d) is an electron microscope of each magnetic sheet prepared with the SPL4 powder composition of Table 2 It's a picture.

Referring to (b) of FIG. 8, as described above, in the magnetic sheet made of the SPL2 powder composition not subjected to surface treatment with a silane solution, a large number of cracks are observed. This is because the frictional force during molding was greatly increased due to the very high specific surface area of the Fe nanopowder. On the other hand, as shown in Figs. 8(c) and 9(b) to (d), when the Fe nanopowder is surface-treated with a silane solution, the epoxy binder is uniform on the surface of the Fe nanopowder with a large specific surface area. It can be seen that high filling is possible by being adsorbed properly. This is particularly advantageous for manufacturing an ultra-thin power inductor having flexibility and high electrical permeability.

In addition, Table 3 below shows the surface roughness (R _a : arithmetic average roughness, R _b : 10-point average roughness), density and filling rate ( Volume Fraction).

In addition, in connection with Table 3, FIG. 10A is a graph showing the change in the volume fraction according to the powder composition of the magnetic sheet prepared with the powder composition of Table 3, and FIG. 10B is a magnetic sheet prepared with the powder composition of Table 3. It is a graph showing the change in macroscopic relative permeability with respect to the change in the filling rate of, and the added broken line represents the actual value in consideration of the actual half magnetic field value of the Ollendorf equation (Equation 1) described above.

Referring to Table 3, in the case of a magnetic sheet made of SPL1 powder composition (that is, a powder composition obtained by mixing a coarse Fe-6.5Si soft magnetic material powder having a particle diameter of about 40 μm and an Fe fine particle powder having a particle size of about 3 μm), the average R _a =2.01㎛, R _z =12.7㎛, while the SPL3 powder composition to which the silane surface-treated nanopowder was applied (that is, the Fe-6.5Si soft magnetic coarse powder and the Fe fine powder and the Fe nano-treated with a silane solution It was confirmed that the magnetic sheet prepared with powder composition) was _{small as an average of R a} =1.7 _{µm and R z} =10.8 µm, and improved surface characteristics. In addition, SPL4 powder composition (i.e., a powder composition of the Fe-6.5Si soft magnetic coarse powder, the Fe fine powder, and the Fe nano-powder aging at a low temperature of 3° C. for 24 hours after surface treatment with a silane solution) In the case of the manufactured magnetic sheet, the average of R _a =0.8 µm and R _z =5.2 µm, and the surface characteristics of the sheet were remarkably improved. This is because a silane-based compound coating film that improves the bonding strength between dissimilar materials is uniformly formed on the surface of the Fe nano-powder, so that the bonding strength with the binder is greatly improved.

Referring to Table 3 and FIG. 10A, SPL4 powder composition (that is, the Fe-6.5Si soft magnetic coarse powder, the Fe fine powder, and the Fe nano-powder subjected to aging treatment at a low temperature of 3° C. for 24 hours after surface treatment with a silane solution. The magnetic sheet made of the mixed powder composition) shows the maximum filling rate.

In addition, FIG. 10B shows a broken line area and an enlarged view thereof, and "Toroidal" indicates the bulk magnetic material observed in FIG. 7 above, and "Sheet" indicates the magnetic material sheet, both of which were prepared in SPL1, SPL3, and SPL4 powder compositions. . While the bulk magnetic material ("Toroidal") is manufactured by applying pressure during manufacturing, the magnetic material sheet ("Sheet") is manufactured by applying no pressure during the process, so as shown in the enlarged view of FIG. 10B, a difference in filling rate occurs between each other. .

As described above, the magnetic powder according to the present invention includes a powder composition of a mixture of a soft magnetic coarse powder, an Fe fine powder, and an Fe nano powder having a silane-based compound coating film formed on the surface thereof.

In addition, the Fe nano-powder forms a uniform surface by aging treatment at a low temperature for a long time after the silane-based compound coating film is formed on the surface, which induces uniform and reinforced bonding with the epoxy binder added for later moldability. This uniform and reinforced bond with the epoxy binder further increases the dispersibility and viscoelasticity between powders, so that the Fe nano powder can more effectively squeeze and fill the empty space between the soft magnetic coarse powder and the Fe fine powder. It greatly increases the packing density and permeability of the magnetic material.

Although discussed above, unlike the present invention, when a magnetic body is produced by mixing with the soft magnetic coarse powder and Fe fine powder without forming the silane-based compound coating film on the surface of the Fe nano powder, the Fe nano powder is very high. Due to the specific surface area, the frictional force between the powders is greatly increased during manufacture, and cracks are generated in the final magnetic body, making molding difficult and the permeability characteristics greatly deteriorated.

Accordingly, the mechanism according to the present invention is very advantageous in manufacturing a power inductor having an ultra-thin, flexible, and high permeability electrical characteristic.

In the above-described embodiments and examples of the present invention, the powder characteristics such as the average particle size, distribution, and specific surface area of the composition powder, and the purity of the raw material, the amount of impurities added, and the sintering conditions slightly vary within the usual error range. It is very natural for those of ordinary skill in the field that this may exist.

In addition, preferred embodiments and embodiments of the present invention are disclosed for the purpose of illustration, and anyone of ordinary skill in the relevant field will be able to make various modifications, changes, additions, etc. within the spirit and scope of the present invention. , Changes, additions, etc. should be regarded as belonging to the scope of the claims.

Claims (19)

delete delete delete delete delete delete Forming a silane-based compound coating film on the surface of the Fe nano-powder by surface-treating the Fe nano-powder in a particle size range of 30 to 200 nm with a silane solution, followed by aging treatment so that the surface of the silane-based compound coating film becomes more uniform;
Preparing a mixed powder by kneading the coarse soft magnetic powder in a particle size range of 10 to 40 µm, fine Fe powder in a particle size range of 1 to 5 µm, and the Fe nano-powder having the aging-treated silane compound coating film; and ;
Adding an epoxy binder to the mixed powder to prepare a magnetic slurry;
And tape-casting the magnetic material slurry to produce a magnetic material sheet. Forming a silane-based compound coating film on the surface of the Fe nano-powder by surface-treating the Fe nano-powder in a particle size range of 30 to 200 nm with a silane solution, followed by aging treatment to make the surface of the silane-based compound coating film more uniform;
Preparing a mixed powder by kneading the coarse soft magnetic powder in a particle size range of 10 to 40 µm, fine Fe powder in a particle size range of 1 to 5 µm, and the Fe nano-powder having the aging-treated silane-based compound coating film; and ;
And preparing a bulk magnetic material by adding an epoxy binder to the mixed powder and applying a molding pressure. The method according to claim 7 or 8,
The aging process is a method of manufacturing a magnetic material, characterized in that performed at a temperature range of 1 ~ 10 ℃. The method of claim 9,
The method of manufacturing a magnetic material, wherein the aging treatment is performed within a range of 1 to 72 hours. The method according to claim 7 or 8,
The method for producing a magnetic material, characterized in that the content of the Fe nano-powder having the aging-treated silane-based compound coating film is adjusted to 0.1 to 10 wt% based on the total amount of the mixed powder. The method according to claim 7 or 8,
The composition of the soft magnetic coarse powder is Fe-Ni, Fe-Cr, Fe-Si, Zr-Al-Ni, Zr-Al-Cu, Zr-Al-Ni-Cu, Zr-Ti-Al-Ni-Cu, Zr-Ga-Ni, Ln-Al-Ni, Ln-Al-Cu, Ln-Al-Ni-Cu, Ln-Ga-Ni, Ln-Ga-Cu, Fe-Zr-B, Fe-Hf-B, Fe-Zr-Hf-B, Fe-Co-Ln-B, Co-Zr-Nb-B, Fe-(Al,Ga)-metalloid, Mg-Ln-Ni, Mg-Ln-Cu, Zr-Ti-Be-Ni-Cu, Pd-Ni-P, Pd-Cu-Ni-P, and a method of manufacturing a magnetic material, characterized in that one or more selected from the group consisting of Pt-Ni-P. The method according to claim 7 or 8,
The composition of the soft magnetic coarse powder is Fe-Si, wherein the content of Si is in the range of 3.5 to 6.5 wt% based on the Fe content. The method according to claim 7 or 8,
The silane solution is prepared by dissolving a silane coupling agent in a solvent, and the solvent is water (H ₂ O), ethanol (C ₂ H ₅ OH), methanol (CH ₃ OH), methyl ethyl ketone (CH ₃ COC ₂ H ₅ ) And benzene (C ₆ H ₆ ) Method for producing a magnetic material, characterized in that one or more selected from the group including. The method of claim 14,
The silane coupling agent is 3-glycid oxypropyl trimethoxysilane, 3-glycid oxypropyl triethoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane, 3-aminopropyl trimethoxysilane, 3- Aminopropyl triethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryl oxypropyl triethoxysilane, 3-mercaptopropyl trimethoxysilane, vinylethoxysilane, vinyl-tolyl (2- Methoxy-ethoxy) silane, γ-methacryloxypropyl trimethoxysilane, γ-aminopropyl trimethoxysilane, γ-aminopropyl triethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl triethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, β -(3,4-epoxycyclohexyl)ethyl trimethoxysilane, γ-glycidoxypropyl trimethoxysilane, and γ-mercaptopropyl trimethoxysilane Manufacturing method. The method according to claim 7 or 8,
The method of manufacturing a magnetic material, characterized in that the amount of the silane solution is adjusted in the range of 0.05 to 5 wt% relative to the total amount of the Fe nano powder. The method of claim 7,
The step of preparing the magnetic material slurry comprises further adding a dispersant to the mixed powder. The method of claim 8,
The method of manufacturing a magnetic material, characterized in that the molding pressure is applied in the range of 1.8 to 6.25 ton/cm ^2. delete

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