CN115691933A - Magnetic powder material, magnetic device, and electronic apparatus - Google Patents

Abstract

The application provides magnetic powder materials, magnetic devices, and electronic equipment. The magnetic powder material particles contain two or more magnetic layers, and any adjacent two magnetic layers contain an insulating layer. The magnetic layer It includes soft magnetic metal material; the insulating layer includes insulating material. The magnetic powder material provided by this application can effectively suppress the eddy current effect generated inside the particles by the high-frequency alternating magnetic field, thereby reducing the high-frequency eddy current loss and improving the high-frequency magnetic permeability.

Description

Magnetic powder materials and magnetic devices, electronic equipment

technical field

The application relates to the technical field of magnetic powder materials, in particular to magnetic powder materials, magnetic devices, and electronic equipment.

Background technique

As a functional material, magnetic powder material has a long history of development and is widely used in electric power, electronics, military and other fields. Soft magnetic materials are an important class of magnetic powder materials. Soft magnetic materials will be magnetized with an external magnetic field. When the external magnetic field is withdrawn, the magnetic properties of soft magnetic materials will disappear quickly. Due to the functions of electromagnetic conversion and energy storage, soft magnetic materials are widely used in power generation, electric vehicles, household appliances and electronic equipment after being prepared into motors, inductors, transformers and electromagnetic shielding devices. The magnetic powder core made of soft magnetic metal powder material has the advantages of high saturation magnetic induction and moderate high-frequency loss, and is suitable for making small-sized, high-current devices. Usually, metal soft magnetic material powder is insulated and coated, then mixed with a binder, and prepared into magnetic powder core materials and devices through processes such as compression molding, annealing heat treatment, impregnation and curing. Due to the gradual development of electronic components in the direction of miniaturization, integration and high frequency, higher requirements are put forward for the high frequency performance (including magnetic performance and loss) of magnetic powder cores.

The high-frequency alternating working current of electronic components will generate a high-frequency alternating magnetic field in the surrounding environment. When the material is in the alternating magnetic field brought by the high-frequency current, an electromotive force will be induced inside the material. If the material has a conductive nature, an eddy current will be generated, as shown in Figure 1a. For magnetic powder materials, with the increase of high-frequency eddy current, the eddy current loss increases rapidly and the magnetic permeability decreases rapidly, which seriously affects the performance of magnetic devices.

At present, by insulating the surface of the magnetic powder material particles, as shown in Figure 1b, the eddy current between the magnetic powder material particles can be blocked, thereby reducing part of the eddy current at high frequencies. However, this solution cannot suppress the eddy current inside the particle. As shown in Figure 1c, when the magnetic powder material is in the AC magnetic field brought by the high-frequency current, an electromotive force will be induced inside the particle, thereby generating an eddy current. As the frequency increases, the eddy current will increase rapidly, which will seriously deteriorate the performance of the magnetic device.

For the eddy current inside the powder, there is no particularly good way to block it. The only way to reduce part of the eddy current is to reduce the particle size of the powder. After molding, the density will be greatly reduced, resulting in a rapid decrease in the two key properties of magnetic saturation and magnetic permeability. Therefore, reducing the particle size of the powder will reduce the eddy current loss, but it will also bring about the side effect of deteriorating magnetic properties.

Contents of the invention

In order to overcome the above-mentioned problems in the prior art, the present application provides magnetic powder materials, magnetic devices, and electronic equipment, which can reduce the eddy current effect caused by the high-frequency alternating magnetic field environment, so as to improve the performance of the magnetic powder materials.

In the first aspect, the present application provides a magnetic powder material, the magnetic powder material includes two or more magnetic layers, an insulating layer is contained between any adjacent two magnetic layers, and the magnetic layer includes a soft magnetic metal material ; the insulating layer comprises an insulating material.

In the above scheme, the insulating layer inside the particle blocks the eddy current between different magnetic layers, which greatly reduces the eddy current loss inside the magnetic powder material particle, thereby reducing the high frequency loss of the magnetic powder material and suppressing its magnetic permeability. rate attenuation at high frequencies.

In a feasible implementation manner, the insulating material includes but not limited to an organic insulating material or an inorganic insulating material.

In a feasible implementation manner, the insulating material includes an inorganic insulating material selected from zinc oxide, bismuth ferrite, iron oxide, nickel oxide, cobalt oxide, copper oxide, silicon oxide, titanium oxide , tantalum oxide, niobium oxide, tungsten oxide, hafnium oxide, aluminum oxide, amorphous carbon, copper sulfide, silver sulfide, and titanium nitride.

In a feasible implementation manner, the insulating material includes an organic insulating material, and the organic insulating material is selected from at least one of polyimide, polyamide, polyschiff base, and polysulfone.

In a feasible implementation manner, the soft magnetic metal material includes but is not limited to at least one of iron, iron-containing alloys, cobalt, cobalt-containing alloys, nickel, and nickel-containing alloys.

The soft magnetic metal material can be a granular soft magnetic metal material, a flake soft magnetic metal material or a fibrous soft magnetic metal material, or a composite material of the above-mentioned soft magnetic metal materials in various forms. Specifically, the iron-containing alloy may be at least one of iron-silicon alloy, iron-aluminum alloy, iron-nickel alloy, iron-silicon-aluminum alloy, iron-silicon-chromium alloy, iron-nickel-silicon-cobalt alloy, and iron-silicon-copper-niobium-boron alloy. The cobalt-containing alloy may be cobalt-silicon alloy, cobalt-nickel alloy, cobalt-nickel-aluminum alloy, sendust aluminum alloy, etc., or other types of alloys containing cobalt metal, which are not limited here. Nickel-containing alloys can be nickel-silicon alloys, nickel-copper alloys, nickel-zinc alloys, nickel-silicon-cobalt alloys, etc., or other types of alloys containing nickel metal. The soft magnetic metal material can also be amorphous soft magnetic alloy or ultrafine crystal soft magnetic alloy, etc., which is not limited here.

In a feasible implementation manner, the soft magnetic metal material is a composite material containing soft magnetic metal.

The soft magnetic metal may be at least one of iron, alloys containing iron, cobalt, alloys containing cobalt, nickel, alloys containing nickel. When the soft magnetic metal material is a composite material containing soft magnetic metal, it may be a composite of soft magnetic metal and any material among conductive materials, non-conductive materials, and insulating materials. It should be noted that the composite material still has soft magnetic properties.

In a feasible implementation manner, the insulating material is a composite material containing insulating materials.

Other materials in the composite material may be conductive materials, such as conductive metals, conductive alloys, etc., or other conductive materials. It should be noted that the composite insulating material can still be non-conductive under the allowable voltage.

In a feasible implementation manner, the magnetic layer is made of dense soft magnetic metal material, or the magnetic layer is made of granular soft magnetic metal material, or the magnetic layer is made of fibrous soft magnetic metal material constitute.

In a feasible implementation manner, the insulating layer is made of dense insulating material, or the insulating layer is made of granular insulating material, or the insulating layer is made of fibrous insulating material.

In a feasible implementation manner, the thickness of the magnetic layer is 0-100 um, excluding 0 um.

In a feasible implementation manner, the thickness of the insulating layer is 0-20um, and does not include 0um.

In a feasible implementation manner, the thickness of the magnetic layer is 0.05um˜10um.

In a feasible implementation manner, the thickness of the insulating layer is 5 nm to 200 nm.

In a feasible implementation manner, the magnetic powder material is a spherical granular material or an ellipsoidal granular material, the magnetic powder material has a core-shell structure, the average particle diameter of the magnetic powder material is 0-500um, and Contains 0um.

In a feasible implementation manner, the magnetic powder material is a flake granular material, the thickness of the magnetic powder material is 0-50um, and does not include 0um; the average particle size of the magnetic powder material is 0-500um , and does not include 0um.

In a second aspect, the present application provides a magnetic device, which includes the magnetic powder material according to the first aspect above.

In a third aspect, the present application provides an electronic device, which includes the magnetic device described in the second aspect above.

Compared with the prior art, the technical solution of the present application has at least the following beneficial effects:

The magnetic powder material provided by this application is formed by periodically stacking magnetic layers and insulating layers alternately. Under a high-frequency working environment, the insulating layer blocks the eddy current between different magnetic layers and suppresses the eddy current inside the magnetic powder material particles. The generation, thereby reducing the high-frequency loss of the magnetic powder material, and suppressing the attenuation of its magnetic permeability at high frequency.

Further, even when the particle size of the magnetic powder material adopting the above scheme is large, the inside of the particle maintains a low high-frequency eddy current. The magnetic powder material with a large particle size has high fluidity, and after being pressed into a block, it has High magnetic performance (high magnetic saturation, high magnetic permeability), so that the magnetic materials and devices prepared by the above scheme can take into account two important characteristics of low loss and high magnetic performance.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1a is a schematic diagram of the eddy current of the magnetic powder material in the prior art under the high-frequency alternating magnetic field brought by the high-frequency current;

Fig. 1b is a schematic diagram showing that the intergranular eddy current of the magnetic powder material in the prior art is blocked;

Figure 1c is a schematic diagram of the eddy current inside the particles of the magnetic powder material in the prior art;

Figure 1d is a schematic diagram of the trend of loss variation with operating frequency of magnetic powder materials in the prior art;

Fig. 1e is a schematic diagram of the variation trend of the magnetic permeability with the working frequency of the magnetic powder material in the prior art;

Fig. 2 is the structural representation of the magnetic powder material provided by the present application;

Fig. 3 is the schematic diagram that the eddy current inside the particle of the magnetic powder material provided by the present application is blocked;

Fig. 4 is another schematic structural view of the magnetic powder material provided by the present application;

Fig. 5 is another schematic structural view of the magnetic powder material provided by the present application;

Fig. 6 is another schematic structural view of the magnetic powder material provided by the present application;

Fig. 7 is another schematic structural view of the magnetic powder material provided by the present application.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not intended to limit the present application.

In the description of this application, unless otherwise clearly specified and limited, the terms "first" and "second" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance; unless otherwise specified or stated , the term "at least one" refers to one or more, and the term "multiple" refers to two or more; Connection can also be detachable connection, integral connection, or electrical connection; it can be direct connection or indirect connection through an intermediary. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application according to specific situations.

In this application, "and/or" describes the association relationship of associated objects, indicating that there may be three kinds of relationships, for example, A and/or B, which may indicate: A exists alone, A and B exist simultaneously, and B exists alone , where A and B can be singular or plural. The character "/" generally indicates that the contextual objects are an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one item (piece) of a, b, or c can represent: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, c can be single or multiple .

At present, the power supply of various electronic components is developing towards integration, high frequency and miniaturization. Magnetic powder materials are the key point to improve the performance of magnetic devices (transformers, filter inductors and power inductors). The performance optimization of magnetic powder materials can reduce the volume of magnetic devices, reduce losses, and reduce electromagnetic pollution.

When the material is in the AC magnetic field brought by the high-frequency current, an electromotive force will be induced inside the material. If the material is conductive, an eddy current will be generated, as shown in Figure 1a. For magnetic powder materials, with the increase of high-frequency eddy current, the eddy current loss increases rapidly and the magnetic permeability decreases rapidly, which seriously affects the performance of magnetic devices.

In the existing technical solutions, the eddy current between the magnetic powder material particles can be blocked by insulating coating on the surface of the magnetic powder material particles (as shown in FIG. 1b ), thereby reducing part of the eddy current at high frequencies. However, this solution cannot suppress the eddy current inside the particle. As shown in Figure 1c, when the magnetic powder material is in the AC magnetic field brought by the high-frequency current, an electromotive force will be induced inside the particle, thereby generating an eddy current. As the frequency increases, the eddy current will increase rapidly, which will seriously deteriorate the performance of the magnetic device.

Fig. 1d is a schematic diagram of the trend of loss variation of magnetic powder materials with operating frequency in the prior art; Fig. 1e is a schematic diagram of the trend of magnetic permeability of magnetic powder materials in the prior art with operating frequency; as shown in Fig. 1d and Fig. 1e It is shown that the loss of magnetic powder materials increases exponentially with the increase of operating frequency, and the magnetic permeability of magnetic powder materials decays rapidly with the increase of operating frequency. Especially the high-frequency alternating magnetic field brought by high-frequency current will cause the eddy current loss in the magnetic powder material to increase rapidly. In order to reduce the high-frequency eddy current phenomenon, the particle size of the magnetic powder material can be reduced to reduce the eddy current inside the particle. However, the decrease of particle size will reduce the fluidity of particles, the magnetic permeability and magnetic saturation induction of magnetic powder materials will decrease, the compression density of magnetic devices will decrease, and the volume will increase. Moreover, the preparation process required to prepare magnetic powder materials with smaller particle sizes is more demanding and the cost increases.

The purpose of this application is to solve the problem of increased eddy currents of magnetic powder materials at high frequencies (for example, within the frequency range of 100 KHz to 100 GHz). In order to reduce the eddy current inside the magnetic powder material particles, the application provides a magnetic powder material, the magnetic powder material includes two or more magnetic layers, an insulating layer is contained between any adjacent two magnetic layers, the magnetic The layer includes a soft magnetic metallic material; the insulating layer includes an insulating material.

In the above scheme, the magnetic powder material is formed by periodically overlapping the magnetic layer and the insulating layer. Under the high-frequency working environment, the insulating layer blocks the eddy current between different magnetic layers and suppresses the generation of eddy current inside the magnetic powder material particles, thereby The high-frequency loss of the magnetic powder material is reduced, and the attenuation of its magnetic permeability at high frequency is suppressed.

It should be noted that the number of times the magnetic layer and the insulating layer are periodically alternately stacked is not limited here, that is, the magnetic layer in the magnetic powder material can be 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, 7 layers layer, 8 layers, 9 layers, 10 layers, 11 layers, 12 layers, etc., and there is an insulating layer between any two adjacent magnetic layers. Even when the particle size of the above-mentioned magnetic powder material is large, the inside of the particle maintains a low high-frequency eddy current. The magnetic powder material with a large particle size has high fluidity, and after being pressed into a block, it has high magnetic properties. (high magnetic saturation, high magnetic permeability), so that the magnetic materials and devices prepared by the above scheme can take into account the two important characteristics of low loss and high magnetic performance.

Specifically, with the magnetic layer as the center or matrix, the insulating layer and the magnetic layer are alternately grown on the surface of the magnetic layer. The particle size of the magnetic powder material particles can be adjusted according to the actual use. The insulation between two adjacent magnetic layers The layer can suppress the formation of eddy currents and improve the high-frequency performance of the magnetic powder material.

As an optional technical solution of the present application, the thickness of the magnetic layer is 0-100 um, excluding 0 um. Specifically, the thickness of the magnetic layer can be 1um, 5um, 10um, 15um, 20um, 25um, 30um, 35um, 40um, 45um, 50um, 55um, 60um, 65um, 70um, 75um, 80um, 85um, 90um or 100um, etc., Of course, other values within the above range are also possible. Preferably, the thickness of the magnetic layer is 0.05um˜10um.

As an optional technical solution of the present application, the magnetic layer includes a soft magnetic metal material. The soft magnetic metal material includes but not limited to at least one of iron, iron-containing alloys, cobalt, cobalt-containing alloys, nickel, and nickel-containing alloys. Specifically, iron-containing alloys include but are not limited to at least one of iron-silicon alloys, iron-aluminum alloys, iron-nickel alloys, iron-silicon-aluminum alloys, iron-silicon-chromium alloys, iron-nickel-silicon-cobalt alloys, and iron-silicon-copper-niobium-boron alloys . Cobalt-containing alloys include but are not limited to cobalt-silicon alloys, cobalt-nickel alloys, cobalt-nickel-aluminum alloys, sendust aluminum alloys, etc., and may also be other types of alloys containing cobalt metal, which are not limited here. Nickel-containing alloys include but are not limited to nickel-silicon alloys, nickel-copper alloys, nickel-zinc alloys, nickel-silicon-cobalt alloys, etc., and may also be other types of alloys containing nickel metal. The soft magnetic metal material can also be amorphous soft magnetic alloy or ultrafine crystal soft magnetic alloy, etc., which is not limited here.

The magnetic layer is made of dense soft magnetic metal material, or the magnetic layer is made of granular soft magnetic metal material, or the magnetic layer is made of fibrous soft magnetic metal material, or the magnetic layer is made of the above-mentioned Various forms of soft magnetic metal materials are composited, that is, a single magnetic layer can contain dense soft magnetic metal materials, granular soft magnetic metal materials and fibrous soft magnetic metal materials.

Soft magnetic metal materials can provide magnetism. Compared with magnetic oxide materials with good insulation, soft magnetic metal materials can provide higher saturation magnetic induction Bs. Specifically, the saturation magnetic induction of the soft magnetic metal material is 0.55T<Bs≤2.2T, which can be 0.6T, 1T, 1.2T, 1.5T, 1.6T, 1.7T, 1.8T, 1.9T or 2T, etc., of course Other values within the above range are possible. Compared with ferrite materials (its saturation magnetic induction intensity Bs≤0.55T), when soft magnetic metal materials are used to make magnetic devices, the same device volume can withstand larger operating currents (inductors, transformers) or shield more EMI signal.

As an optional technical solution of the present application, the soft magnetic metal material may be a pure soft magnetic metal material, or a composite material containing soft magnetic metal. Likewise, the soft magnetic metal includes, but is not limited to, at least one of iron, iron-containing alloys, cobalt, cobalt-containing alloys, nickel, and nickel-containing alloys. When the soft magnetic metal material is a composite material containing soft magnetic metal, it may be a composite of soft magnetic metal and any material among conductive materials, non-conductive materials, and insulating materials. It should be noted that the composite material still has soft magnetic properties. Exemplarily, the composite material may be a mixture of soft magnetic metal accounting for 60%-99% by mass and insulating material accounting for 1%-40% by mass. The composite material can also be a mixture of soft magnetic metal accounting for 70%-99% by mass and conductive material accounting for 1%-30% by mass. The composite material can also be a mixture of soft magnetic metal accounting for 80%-99% by mass and non-conductive material accounting for 1%-20% by mass. The conductive material can be conductive metal, conductive alloy, etc., and the non-conductive material can be rubber, plastic, etc.

The disadvantage of soft magnetic metal materials is that the resistivity is very low, so in a high-frequency working environment, the electromotive force induced by the high-frequency magnetic field inside the magnetic powder will cause a high eddy current, resulting in Joule heat loss and a decrease in magnetic permeability. By arranging an insulating layer between adjacent magnetic layers, the eddy current between adjacent magnetic layers can be blocked, so that the eddy current inside the magnetic powder material particles is greatly reduced, and the effect of reducing loss and increasing magnetic permeability is achieved.

As an optional technical solution of the present application, the insulating layer has a thickness of 0-20 um and does not include 0 um. Specifically, the thickness of the insulating layer may be 0-20um, not including 0um. Specifically, it can be 5nm, 10nm, 20nm, 30nm, 50nm, 80nm, 100nm, 200nm, 1um, 2um, 3um, 4um, 5um, 6um, 7um, 8um, 9um, 10um, 12um, 15um, 16um, 18um, 20um, etc. Of course, other values within the above range are also possible. Preferably, the thickness of the insulating layer is 5nm˜200nm.

As an optional technical solution of the present application, the insulating layer in the magnetic powder material includes an insulating material. Optionally, the insulating material is a material that is non-conductive at an allowable voltage, but not absolutely non-conductive. Specifically, the insulating layer is made of dense insulating material, or the insulating layer is made of granular insulating material, or the insulating layer is made of fibrous insulating material, or a composite material of the above-mentioned various forms of insulating materials. The insulating material includes but not limited to at least one of silicon oxide, aluminum oxide, iron oxide, titanium oxide, hafnium oxide, silicon nitride, aluminum nitride, silicone grease or carbon A sort of. The insulating material may also be epoxy resin, polyimide, silicon organic paint, tetrafluoroethylene, etc., which is not limited here.

Specifically, the silicon oxide may be at least one of SiO ₂ , SiO _1.8 , and SiO _1.5 . The oxide of aluminum may be Al ₂ O ₃ . Iron oxides may be Fe ₂ O ₃ , Fe ₃ O ₄ . The oxide of titanium may be TiO ₂ . The hafnium oxide may be HfO ₂ . The nitride of silicon may be SiN, and the nitride of aluminum may be AlN, and of course the above range is not limited, as long as it is a non-conductive material under the allowable voltage.

As an optional technical solution of the present application, the insulating material may also be a composite insulating material containing conductive materials. The conductive material may be conductive metal, conductive alloy, etc., or other conductive materials. It should be noted that the composite insulating material can still be non-conductive under the allowable voltage. Exemplarily, the composite insulating material may be a mixture of an insulating material accounting for 60%-99% by mass and a conductive material accounting for 1%-40% by mass.

As an optional technical solution of the present application, the insulating layer in the magnetic powder material may also be a composite insulating layer, and the composite insulating layer includes at least two insulating functional layers stacked and interposed between the at least two insulating functional layers. conductive layer between. That is to say, the insulating layer is a composite layer formed by laminating the insulating functional layer and other functional layers, and the composite layer and the number of composite layers are not limited here. The thickness of the composite insulating layer is 0-20um, not including 0um. Specifically, it can be 1um, 2um, 3um, 4um, 5um, 6um, 7um, 8um, 9um, 10um, 12um, 15um, 16um, 18um, 20um, etc. Of course, it can also be other values within the above range.

As an optional technical solution for this application, the magnetic powder material is a spherical particle material or an ellipsoidal particle material, and the average particle size of the magnetic powder material is 0-500um, and does not include 0um. The average particle size of the magnetic powder material can be specifically 1um .

As an optional technical solution of the present application, the magnetic powder material is a flaky granular material, and the thickness of the magnetic powder material is 0-100 um, excluding 0 um. The thickness of the magnetic powder material can be 1um, 5um, 10um, 15um, 20um, 25um, 30um, 35um, 40um, 45um, 50um, 55um, 60um, 65um, 70um, 75um, 80um, 85um, 90um or 100um. The average particle size of the flaky granular material is 0-500um, excluding 0um. The average particle size of the flaky granular material can be 1um, 5um, 10um, 15um, 20um, 25um, 30um, 35um, 40um, 45um , 50um, 55um, 60um, 65um, 70um, 75um, 80um, 85um, 90um, 100um, 200um, 300um, 400um or 500um, etc.

Fig. 2 is the structural representation of the magnetic powder material that the present application provides, as shown in Fig. 2, magnetic powder material 1 is spherical particle shape and has periodic core-shell layer (magnetic layer-insulating layer) structure, and magnetic powder material 1 comprises The first magnetic layer 11 , the first insulating layer 21 , the second magnetic layer 12 , the second insulating layer 22 and the third magnetic layer 13 are sequentially stacked. As shown in Figure 3, due to the periodic core-shell structure inside the magnetic powder material particles, a large number of eddy currents inside the particles can be blocked by the insulating layer, the reduction of eddy currents reduces the loss, and at the same time improves the high frequency The lower magnetic permeability.

Fig. 4 is another schematic structural view of the magnetic powder material provided by the present application. As shown in Fig. 4, the magnetic powder material 1 is in the shape of a spherical particle and has a periodic core-shell structure inside the particle, and the magnetic powder material 1 includes sequentially The clad first magnetic layer 11 , first insulating layer 21 , second magnetic layer 12 , second insulating layer 22 and third magnetic layer 13 are stacked. The second magnetic layer 12 includes a plurality of granular soft magnetic metal materials, and the grain size of the granular soft magnetic metal materials may be 0nm˜5um. In other embodiments, the second magnetic layer 12 may also include at least one of a plurality of sheet-shaped soft magnetic metal materials or fibrous soft magnetic metal materials. Among them, the granular soft magnetic metal material can be spherical granular soft magnetic metal material, rugby soft magnetic metal material, etc., and the flake soft magnetic metal material can be a round piece, a square piece or other regular or irregular pieces body, etc.; the fibrous soft magnetic metal material can be linear. The second magnetic layer 12 may also include a small amount of insulating material filled between granular soft magnetic metal materials. As shown in Figure 5, of course, the magnetic layer made of the above-mentioned composite material containing soft magnetic metal material is also suitable for the first magnetic layer. In other embodiments, the magnetic layer made of composite material can also be a magnetic powder material Any one of the magnetic layers is not limited here.

Fig. 6 is another schematic structural view of the magnetic powder material provided by the present application. As shown in Fig. 6, the magnetic powder material 1 is in the shape of spherical particles and has a periodic core-shell structure, and the magnetic powder material 1 includes sequentially stacked The first magnetic layer 11 , the first insulating layer 21 , the second magnetic layer 12 , the second insulating layer 22 and the third magnetic layer 13 . The first insulating layer 21 includes a plurality of granular insulating materials, and the particle size of the granular insulating materials may be 0nm˜5um. In other embodiments, the first insulating layer 21 may also include at least one of a plurality of sheet-shaped insulating materials or fibrous insulating materials. Among them, the granular insulating material can be a spherical granular insulating material, a rugby ball insulating material, etc., and the sheet insulating material can be a round sheet, a square sheet or other regular or irregular sheets, etc.; the fibrous insulating material can be Linear. The first insulating layer 21 is formed of a composite insulating material, which may include an insulating material and a conductive material filled between the insulating materials. Of course, the insulating layer made of composite material can be applied to any insulating layer in the magnetic powder material, and there is no limitation here.

Fig. 7 is another schematic structural view of the magnetic powder material provided by the present application. As shown in Fig. 7, the magnetic powder material 1 is in the shape of spherical particles, and the magnetic powder material 1 includes the first magnetic layer 11, the An insulating layer 21 and a second magnetic layer 12 . That is, a magnetic powder material with two magnetic layers and an insulating layer between the two magnetic layers.

As an optional technical solution for this application, when preparing magnetic powder materials, for example, the first magnetic layer can be obtained by chemical vapor deposition, physical vapor deposition, chemical liquid deposition or vacuum atomization; Deposition, physical vapor deposition or chemical liquid deposition deposits the first insulating layer on the surface of the first magnetic layer; then deposits the second magnetic layer on the surface of the first insulating layer by chemical vapor deposition, physical vapor deposition or chemical liquid deposition ; Deposit a second insulating layer on the surface of the second magnetic layer by chemical vapor deposition, physical vapor deposition or chemical liquid deposition, and repeat the deposition to form a plurality of magnetic powder materials with periodic magnetic layer-insulating layer structure. The magnetic powder material formed by repeated deposition maintains low high-frequency eddy current inside the particle even when the particle size is large. The magnetic powder material with large particle size has high fluidity. After being pressed into a block, it has high magnetic properties. energy (high magnetic saturation, high magnetic permeability), so that the magnetic materials and devices prepared by the above scheme can take into account the two important characteristics of low loss and high magnetic performance.

In some embodiments, the magnetic powder material can also be flake granular material. It can be understood that the sheet-shaped magnetic powder material also follows the principle of alternating lamination of magnetic layers and insulating layers, so that the insulating layer between two adjacent magnetic layers can suppress the formation of eddy currents and improve the high-frequency performance of the magnetic powder material.

In a second aspect, the present application provides a magnetic device, which includes the magnetic powder material according to the first aspect above.

Magnetic devices include inductors, transformers, magnetic shielding devices, etc. Magnetic devices are essential electronic components in circuits. Generally, magnetic devices are used to store or convert energy, and form circuits together with resistors, capacitors, and semiconductor devices to realize functions such as energy and signal transmission. Each single board contains a large number of magnetic devices, and some chips also package inductors inside the chip. With the miniaturization of electronic equipment and high frequency of operation, their requirements for magnetic powder materials are also getting higher and higher. Especially in the field of chip power supply, due to the limitation of the overall volume of the system, the miniaturization requirements for magnetic devices are particularly stringent, and the operating frequency of some server chips has reached the order of 100MHz, the loss and magnetic properties of magnetic powder materials at high frequencies Attenuation is a challenge. In addition, for materials that shield electromagnetic signal interference in electronic equipment, the operating frequency is as high as 1GHz, and the high-frequency performance requirements for magnetic powder materials are higher.

Adopting the magnetic powder material provided by the first aspect of the present application reduces the eddy current inside the magnetic powder material particle (i.e. the magnetic powder material part), thereby reducing the eddy current loss of the magnetic powder material and improving the high-frequency magnetic permeability of the magnetic powder material . Multiple magnetic powder materials can be wrapped by insulating material to form the final magnetic material. The high magnetic permeability and high magnetic saturation of the magnetic powder material can reduce the volume of the magnetic core device.

Further, the magnetic device can also be an electromagnetic shielding device, which includes the magnetic powder material of the first aspect above. Due to the high magnetic permeability and high magnetic saturation characteristics of the magnetic powder material, the electromagnetic shielding device can be improved at high frequencies. The electromagnetic shielding effect reduces the volume of the electromagnetic shielding device.

In a third aspect, the present application provides an electronic device, which includes the magnetic device according to the second aspect above. Electronic devices can be mobile phones, laptops, tablets, wearables, and more.

Introduce this scheme in detail below by specific embodiment:

Example 1

The magnetic powder material with multi-layer "core-shell" structure is prepared by chemical vapor deposition method and chemical liquid phase deposition method, which can be used to make magnetic devices such as electromagnetic shielding, inductors and transformers. Specifically, the magnetic powder material is a periodic core-shell structure formed by Fe/SiO ₂ , wherein Fe/SiO ₂ is stacked 10 times. Include the following steps:

(1) In the fluidized bed chemical vapor deposition tube furnace, feed N ₂ /NH ₃ mixed gas (the volume ratio of N ₂ to NH ₃ is 7:3), with Fe(CO) ₅ as the precursor Gas source, under the conditions of high temperature of 300°C and gas flow rate of 0.1cm/s, Fe(CO) ₅ is cracked in the reaction chamber to form Fe particles. After about 25 minutes of reaction, 120g of iron powder particles with a D50 of 2um are obtained.

(2) Put the obtained iron powder particles into 1000mL ethanol-water solution (the volume ratio of water and ethanol is 1:5) and ultrasonically disperse for 10min. Then, 10 mL of ethyl orthosilicate and 20 mL of 25% ammonia solution were added dropwise, and stirred uniformly at room temperature for 2 h. After the reaction is finished, the material is repeatedly washed to neutrality, and then SiO ₂ coated iron powder particles are obtained after drying. The thickness of the first insulating layer is 20nm-30nm.

(3) Put the iron powder particles coated with silicon dioxide into a fluidized bed chemical vapor deposition tube furnace, and feed N ₂ /NH ₃ mixed gas (wherein, the volume ratio of N ₂ and NH ₃ is 7: 3), the gas flow rate is 0.8cm/s, so that the iron powder particles are suspended, and at the same time, the temperature of the chamber is kept at 300 ° C, and gaseous Fe(CO) ₅ is introduced, which is decomposed into Fe atoms at high temperature and deposited on the suspended iron A magnetic layer is formed on the powder particles, the deposition reaction time is 15 minutes, and an iron metal magnetic layer with a thickness of about 2 um is obtained, thereby obtaining a material with a Fe/SiO ₂ /Fe structure.

(4) Repeat the process of (2) to obtain a material with a structure of Fe/SiO ₂ /Fe/SiO ₂ .

(5) Repeat the process (3) 8 times and the process (2) 7 times in turn to obtain a magnetic powder material with a multi-"core-shell" structure with 10 magnetic layers: Fe/SiO ₂ /Fe/SiO ₂ ... SiO ₂ /Fe.

Example 2

The magnetic powder material with multi-layer "core-shell" structure is prepared by chemical vapor deposition method and chemical liquid phase deposition method, which can be used to make magnetic devices such as electromagnetic shielding, inductors and transformers. Specifically, the magnetic powder material is a periodic core-shell structure formed by Fe/SiO ₂ , wherein FeNi/SiO ₂ is stacked 10 times. The mass ratio of Fe and Ni in the magnetic layer was 50:50. Include the following steps:

(1) In the fluidized bed chemical vapor deposition tube furnace, N ₂ /NH ₃ mixed gas (wherein the volume ratio of N ₂ and NH ₃ is 7:3), with Fe(CO) ₅ and Ni( CO) ₄ is the precursor gas source. Under the conditions of high temperature of 300 °C and gas flow rate of 0.1 cm/s, Fe(CO) ₅ and Ni(CO) ₄ are cracked in the reaction chamber to form FeNi particles. After about 25 minutes of reaction 120g of FeNi particles with a D50 of 2um were obtained.

(2) After the preparation of FeNi powder particles is completed, continue to feed nitrogen gas to suspend FeNi powder particles in the cavity, stop feeding NH ₃ gas, start feeding water vapor, and keep the flow ratio of N ₂ and water vapor at 7:3 , with SiCl ₄ as the precursor gas source, under the condition of high temperature of 300 ℃ and gas flow rate of 0.8cm/s, SiCl ₄ and water vapor react in the reaction chamber to form SiO ₂ deposited on the coated FeNi particles, the reaction After about 2 minutes, the resulting SiO ₂ insulating layer has a thickness of 20-30 nm, thereby obtaining FeNi particles coated with SiO ₂ insulation.

(3) Continuously feed nitrogen gas, suspend FeNi particles coated with SiO ₂ insulation in the chamber, switch O ₂ to NH ₃ , and feed N ₂ /NH ₃ mixed gas (N ₂ :NH ₃ ～7:3) , the flow rate is 0.8cm/s, at the same time, Fe(CO) ₅ and Ni(CO) ₄ are used as the precursor gas source (the gas volume is maintained at about 1:1), and the cavity temperature is kept at 300 ° C, decomposed at high temperature Fe atoms and Ni atoms are deposited together on the suspended particles to form a FeNi layer. The deposition reaction time is 15 minutes to obtain a FeNi metal layer with a thickness of about 2um, thereby obtaining a powder with a FeNi/SiO ₂ /FeNi structure.

(4) Repeat the process of (2) to obtain a material with a structure of FeNi/SiO ₂ /FeNi/SiO ₂ .

(5) Repeat process (3) 8 times and process (2) 7 times in turn to obtain a magnetic powder material with a multi-"core-shell" structure with 10 magnetic layers: FeNi/SiO ₂ /FeNi/SiO ₂ ... SiO ₂ /FeNi.

Example 3

A multi-layer "core-shell" structure magnetic powder material is prepared by water-gas combined atomization method and chemical liquid phase deposition method, which can be used to make magnetic devices such as electromagnetic shielding, inductors and transformers. Specifically, the magnetic powder material is the internal structure of FeSiBCr (magnetic particles, particle size D50 is 0.5um)/SiO ₂ (insulating layer, thickness 75nm)/FeSiBCr (magnetic layer, thickness 0.5um), the Fe:Si in the magnetic layer The :B:Cr mass ratio is 89:6.31:2.17:2.61. The production process includes the following steps:

(1) FeSiBCr amorphous powder material was prepared by water-gas combined atomization method, and after being sieved by air separator, 60g material with a particle size (D50) of about 2.5um was obtained for the next experiment;

(2) Put 60g of FeSiBCr amorphous particles into 1000mL ethanol-water solution (volume ratio of water to ethanol: 1:5) for ultrasonic dispersion for 10min. Then, 10 mL of tetraethyl orthosilicate and 20 mL of 25% ammonia solution were added dropwise, and stirred uniformly at room temperature for 5 h. After the reaction, the material was repeatedly washed to neutrality, and after drying, _SiO2- coated particles were obtained, and the thickness of the _SiO2 insulating layer was about 75nm;

(3) According to the atomic ratio of Fe:Si:Cr (89:6.31:2.61), configure 2000mL of a mixed solution of NaSiF ₆ , FeCl ₃ and CrCl ₃ , and then drop into the prepared NaBH ₄ solution at a rate of 2mL/min , causing the solution to react. Acquisition With the addition of NaBH ₄ solution, a black precipitate was gradually generated in the reaction solution. The precipitate was separated, washed repeatedly with distilled water and ethanol, and finally vacuum-dried at 70°C to obtain the reaction product;

(4) Deposit a FeSiBCr amorphous magnetic layer with a thickness of about 0.5um on the outside of the _SiO2 insulating layer, and the powder material structure formed is FeSiBCr(2.5um)/ _SiO2 (75nm)/FeSiBCr(0.5um).

Comparative example 1

Prepare magnetic powder material Fe powder by chemical vapor deposition method, comprising the following steps:

In the fluidized bed chemical vapor deposition tube furnace, N ₂ /NH ₃ mixed gas (wherein the volume ratio of N ₂ and NH ₃ is 7:3), with Fe(CO) ₅ as the precursor gas source, Under the conditions of high temperature of 300°C and gas flow rate of 0.1cm/s, Fe(CO) ₅ was cracked in the reaction chamber to form Fe particles. After about 205 minutes of reaction, an iron powder material with a D50 of 38um was obtained.

Comparative example 2

Prepare magnetic powder material FeNi powder by chemical vapor deposition method, comprise the following steps:

In the fluidized bed chemical vapor deposition tube furnace, N ₂ /NH ₃ mixed gas (wherein the volume ratio of N ₂ and NH ₃ is 7:3), with Fe(CO) ₅ and Ni(CO) ₄ As the precursor gas source, Fe(CO) ₅ and Ni(CO) ₄ are cracked in the reaction chamber to generate FeNi particles under the condition of high temperature of 300°C and gas flow rate of 0.1cm/s. After about 205min of reaction, D50 38um FeNi powder material.

Comparative example 3-1

The FeSiBCr amorphous powder material (the mass ratio of Fe:Si:B:Cr is 89:6.31:2.17:2.61) was prepared by water-gas combined atomization method. After being sieved by a winnowing machine, a magnetic powder material with a particle size (D50) of 2.5um is obtained.

Comparative example 3-2

The FeSiBCr amorphous powder material (the mass ratio of Fe:Si:B:Cr is 89:6.31:2.17:2.61) was prepared by water-gas combined atomization method. After being sieved by a winnowing machine, a magnetic powder material with a particle size (D50) of 3.5um is obtained. test:

With the magnetic powder material sample that embodiment 1～3 makes and the magnetic powder material sample that comparative example makes, each weighs about 10 grams, utilizes epoxy resin bonding agent to coat and granulate (epoxy resin except making powder Bonding will also achieve the effect of insulating the particles between the particles), pressing it into a magnetic ring with an outer diameter of 15mm, an inner diameter of 10mm, and a thickness of 4mm. The magnetic properties are tested separately. The test results are shown in Table 1 below:

Table 1. Magnetic material characteristic parameters with different "core-shell" layers

Description of test results:

According to the test data in table 1, the magnetic permeability of the magnetic powder material that embodiment 1 and 2 make is comparable to the magnetic permeability of the magnetic powder material that comparative example 1 and 2 make at low frequency (50Hz); Under the high frequency state, namely (30MHz), the magnetic permeability is obviously higher than that of the magnetic powder materials prepared in Comparative Examples 1 and 2. This is because the magnetic powder material prepared by the embodiment has a periodic core-shell structure, and each insulating layer inside the magnetic powder material can well block the eddy current effect between the magnetic layers inside the magnetic powder material because of the high-frequency magnetic field, thereby improving its Magnetic permeability at high frequencies.

According to the test data of Examples 1, 2 and Comparative Examples 1, 2 in Table 1, the power consumption of the magnetic powder materials prepared in the examples is significantly lower than that of the magnetic powder materials prepared in the comparative examples. The decrease (about 80%) indicates that the eddy current loss inside the magnetic powder material is fully suppressed, and the magnetic powder material has a lower loss, so that the magnetic powder material can have both high magnetic performance and low loss.

According to the test data in Table 1, it can be seen that the magnetic permeability of the magnetic powder material prepared in Example 3 is significantly higher than that of Comparative Example 3-1 at low frequency (50Hz) and high frequency (5MHz and 30MHz), while high frequency The loss under the condition remains almost unchanged, because in the state of ultrafine powder, the fluidity of the powder material becomes worse during the pressing process, the finer the particle size, the lower the pressing density, and the larger the gap between the particles, The demagnetizing field causes a sharp decrease in the magnetic permeability. The test data of Comparative Example 3-2 shows that if the particle size is directly increased (compared to Comparative Example 3-1), although the material permeability can be improved (compared to Comparative Example 3-1), high frequency (1MHz) loss will increase rapidly. In Example 3, after the insulating layer is used to block the magnetic layer inside the magnetic powder material, the magnetic permeability is increased while the loss is not increased, and the two important characteristics of the material are well taken into account.

The above are only preferred specific implementation methods of the present application, but the scope of protection of the present application is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application. All should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (11)

1. The magnetic powder material is characterized by comprising two or more magnetic layers, wherein an insulating layer is arranged between any two adjacent magnetic layers, and the magnetic layers comprise soft magnetic metal materials; the insulating layer includes an insulating material.

2. The magnetic powder material according to claim 1, wherein the magnetic powder material satisfies at least one of the following conditions:

(1) The insulating material includes, but is not limited to, an organic insulating material or an inorganic insulating material;

(2) The insulating material comprises an inorganic insulating material, and the inorganic insulating material comprises at least one of zinc oxide, bismuth ferrite, iron oxide, nickel oxide, cobalt oxide, copper oxide, silicon oxide, titanium oxide, tantalum oxide, niobium oxide, tungsten oxide, hafnium oxide, aluminum oxide, amorphous carbon, copper sulfide, silver sulfide and titanium nitride;

(3) The insulating material comprises an organic insulating material including, but not limited to, at least one of polyimide, polyamide, polyitacrine, polysulfone;

(4) The soft magnetic metal material includes, but is not limited to, at least one of iron, an iron-containing alloy, cobalt, a cobalt-containing alloy, nickel, and a nickel-containing alloy.

3. A magnetic powder material according to claim 1, wherein the soft magnetic metal material is a composite material comprising a soft magnetic metal.

4. A magnetic powder material according to claim 1, wherein the insulating material is a composite material comprising an insulating material.

5. The magnetic powder material according to claim 1, wherein the magnetic layer is composed of a dense soft magnetic metal material, or the magnetic layer is composed of a granular soft magnetic metal material, or the magnetic layer is composed of a fibrous soft magnetic metal material.

6. The magnetic powder material according to claim 1, wherein the insulating layer is composed of a dense insulating material, or the insulating layer is composed of a granular insulating material, or the insulating layer is composed of a fibrous insulating material.

7. The magnetic powder material according to claim 1, wherein the magnetic powder material satisfies at least one of the following conditions:

(5) The thickness of the magnetic layer is 0-100 um, and the magnetic layer does not contain 0um;

(6) The thickness of the insulating layer is 0-20 um, and 0um is not included;

(7) The thickness of the magnetic layer is 0.05 um-10 um;

(8) The thickness of the insulating layer is 5 nm-200 nm.

8. The magnetic powder material according to any one of claims 1 to 7, wherein the magnetic powder material is a spherical particle material or an ellipsoidal particle material, and the magnetic powder material has an average particle diameter of 0 to 500um and does not contain 0um.

9. The magnetic powder material according to any one of claims 1 to 7, wherein the magnetic powder material is a flaky particle material, and the thickness of the magnetic powder material is 0 to 100um and does not contain 0um; the average particle diameter of the magnetic powder material is 0-500 um, and does not contain 0um.

10. A magnetic device, characterized in that it comprises a magnetic powder material according to any one of claims 1 to 9.

11. An electronic device characterized in that it comprises a magnetic device according to claim 10.

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