A high-frequency low-loss three-dimensional shielding material and its preparation method

Abstract

The present invention belongs to the field of wireless charging technology, and specifically relates to a high-frequency low-loss three-dimensional shielding material and a preparation method thereof. The preparation method comprises the following steps: (1) preparing a material composed of Fe bal. M a Cu b M' c Si d B e X f (1) crushing or pulverizing the iron-based nanocrystalline and / or amorphous material, and then subjecting it to annealing and crystallization treatment to obtain nanocrystalline soft magnetic alloy powder; (2) mixing the obtained nanocrystalline soft magnetic alloy powder with ferrite powder and a binder, and then subjecting the mixture to compression molding or injection molding to obtain a high-frequency, low-loss three-dimensional shielding material. The composite shielding material obtained by the present invention can simultaneously possess the high saturation magnetic flux density of nanocrystalline and the low-loss characteristics of ferrite, and can be processed into a three-dimensional shape, thereby reducing leakage magnetic flux in the XY direction and improving the power conversion efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless charging, and in particular relates to a high-frequency, low-loss, three-dimensional shielding material and a preparation method thereof. Background Art

[0002] As wireless charging power increases, traditional nanocrystalline magnetic isolation materials, due to their low resistivity, have high eddy current losses at high frequencies, resulting in severe heating when used in high-frequency wireless charging modules. Furthermore, while traditional ferrite materials have low eddy current losses at high frequencies, their saturation magnetic induction is low, limiting their application in high-current scenarios with high charging power. Combining the advantages of nanocrystalline and ferrite magnetic isolation materials is a viable solution. For example, patent CN 116417226 A discloses a magnetic isolation composite material for wireless charging. The composite material comprises a stacked ferrite magnetic isolation material layer and a nanocrystalline magnetic isolation material layer, wherein the nanocrystalline magnetic isolation material layer comprises at least one multilayer nanocrystalline magnetic isolation material, and the magnetic permeability of the multilayer nanocrystalline magnetic isolation material gradually increases as it moves away from the ferrite magnetic isolation material layer. The magnetic isolation composite material for wireless charging with the above structure can significantly reduce eddy current losses and heat generation during high-power charging, thereby achieving better power transmission efficiency during application. However, this multi-layer structure is not conducive to the development of miniaturization and lightweight devices; at the same time, the nanocrystalline tape insulation material is relatively brittle and has poor toughness, and its structure is relatively simple, making it difficult to apply to three-dimensional and curved usage scenarios.

[0003] Patent CN 102142309 A discloses a bulk amorphous / ferrite soft magnetic composite material. This soft magnetic composite material is a three-dimensional honeycomb structure of an amorphous / ferrite soft magnetic composite material. The honeycomb structure is composed of a high-resistivity soft ferrite. The honeycomb ferrite surrounds and completely isolates the amorphous alloy soft magnetic phase composed of soft magnetic amorphous alloy particles within the honeycomb, thereby insulating the amorphous alloy soft magnetic phases within the honeycomb from each other. Compared with amorphous alloy soft magnetic materials, this composite material has a significantly higher resistivity and improves the operating frequency of the amorphous alloy. However, the preparation process of this composite material requires that the soft ferrite powder be completely and evenly coated on the surface of the soft magnetic amorphous alloy particles, and requires the use of spark plasma sintering technology. This has high requirements for process control and equipment, making it difficult to stabilize and mass-produce, and is costly.

[0004] Patent CN 115762949 A discloses a high-permeability, low-loss iron-based soft magnetic composite material. This material comprises a matrix material and an insulating medium. Garnet-type ferrite (RIG) is used to insulate and coat amorphous and nanocrystalline magnetic powders, effectively isolating the particles from contact and reducing magnetic losses. However, this composite material requires a specific garnet-type ferrite (RIG), which has a limited range of raw material sources. Summary of the Invention

[0005] In view of the shortcomings and deficiencies of the above-mentioned prior art, the primary purpose of the present invention is to provide a method for preparing a high-frequency, low-loss three-dimensional shielding material.

[0006] Another object of the present invention is to provide a high-frequency, low-loss, three-dimensional shielding material prepared by the above method.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for preparing a high-frequency, low-loss, three-dimensional shielding material comprises the following steps:

[0009] (1) The composition is Fe bal. M a Cu b M' c Si d B e X f The iron-based nanocrystalline and / or amorphous material is crushed or pulverized, and then annealed and crystallized to obtain nanocrystalline soft magnetic alloy powder; wherein M is Co and / or Ni, M' is at least one of Nb, V, Ta, and Mo, and X is at least one of common impurity elements such as C, O, N, S, and P; a=0-30%, b=0-2%, c=0-7%, d=5-18%, e=5-15%, and f=0-0.5%;

[0010] (2) The obtained nanocrystalline soft magnetic alloy powder is mixed with ferrite powder and a binder and then subjected to compression molding or injection molding to obtain a high-frequency, low-loss three-dimensional shielding material.

[0011] Furthermore, in step (1), a=0~15%, b=0.5~1.5%, c=2~4%, d=12~17%, e=5~8%, and f=0~0.5%.

[0012] Furthermore, the crushing in step (1) refers to mechanically crushing the iron-based nanocrystalline and / or amorphous strips into flaky powders with a thickness of 0.005-0.03 mm and a size of 0.05-5 mm.

[0013] Furthermore, the powdering in step (1) refers to directly preparing the iron-based nanocrystalline and / or amorphous alloy into spherical powder with a D50 particle size of 0.003-0.100 mm by water atomization, gas atomization, or water-gas combined atomization.

[0014] Furthermore, the temperature of the annealing crystallization treatment in step (1) is 500-620° C., and the time is 0.5-4 h.

[0015] Furthermore, the ferrite in step (2) is one or more of manganese zinc ferrite, nickel zinc ferrite and copper zinc ferrite.

[0016] Furthermore, the ferrite powder in step (2) is a spherical powder with a D50 particle size of 0.003-0.100 mm.

[0017] Further preferably, the nanocrystalline soft magnetic alloy powder in step (2) is a flake powder with a thickness of 0.005-0.03 mm and a size of 0.05-0.5 mm; and the ferrite powder is a spherical powder with a D50 particle size of 0.003-0.100 mm.

[0018] Furthermore, the adhesive in step (2) is one or more of epoxy resin, low melting point glass, acrylic resin, silicone rubber, and polyurethane.

[0019] Furthermore, the mass ratio of the nanocrystalline soft magnetic alloy powder, ferrite powder and binder mixed in step (2) is 100:1~30:1~10.

[0020] Furthermore, the compression molding in step (2) is performed under a pressure of 5-500 MPa, a temperature of 25-200° C., and a time of 0.2-3 seconds; and the injection molding refers to extruding the mixed material into a mold by screw extrusion.

[0021] Furthermore, the material formed in step (2) is in the shape of a plane, a curved surface or a three-dimensional structure.

[0022] A high-frequency, low-loss three-dimensional shielding material is prepared by the above method.

[0023] Furthermore, a coil fitting area is provided on one side of the three-dimensional shielding material, and the outer periphery and inner periphery of the coil fitting area have raised portions perpendicular to the coil plane.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The composite shielding material obtained by the present invention can simultaneously have the high saturation magnetic flux density of nanocrystals and the low loss characteristics of ferrite, and can be processed into a three-dimensional shape, thereby reducing leakage magnetic flux in the XY direction, reducing leakage magnetic flux loss, and improving power conversion efficiency.

[0026] (2) The present invention further uses flaky nanocrystalline soft magnetic alloy powder and spherical ferrite powder to compound, which can more effectively block the eddy current path between the nanocrystalline soft magnetic alloy particles and better couple the magnetic field between the nanocrystalline soft magnetic alloy particles, thereby achieving better high-frequency magnetic properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the appearance structure of the high-frequency, low-loss three-dimensional shielding materials obtained in Examples 1 to 5 and Comparative Examples 1 to 2.

[0028] Figure 2 This is a schematic diagram of the external structure of the layered nanocrystalline shielding material obtained in Comparative Example 3. DETAILED DESCRIPTION

[0029] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto. Example 1

[0030] A method for preparing a high-frequency, low-loss, three-dimensional shielding material comprises the following steps:

[0031] (1) The composition is Fe 73.5 Cu1Nb3Si 15.5 The iron-based amorphous alloy with a content of B7 (at.%) was prepared into spherical powder with a D50 particle size of 0.10 mm by water-gas combined atomization, and then heated to 580 °C for annealing and crystallization treatment for 2.5 h to obtain nanocrystalline soft magnetic alloy powder.

[0032] (2) The obtained nanocrystalline soft magnetic alloy powder is mixed with spherical manganese-zinc ferrite powder with a D50 particle size of 0.10 mm and a binder (low-melting-point glass and epoxy resin in a mass ratio of 1:2) and then molded at a pressure of 30 MPa, a temperature of 100°C, and a holding pressure of 0.5 s; the mass ratio of the nanocrystalline soft magnetic alloy powder, ferrite powder and binder is 100:15:3 to obtain a high-frequency, low-loss three-dimensional shielding material. A coil bonding area is set on one side of the obtained three-dimensional shielding material, and the outer and inner peripheries of the coil bonding area have protrusions perpendicular to the coil plane. The schematic diagram of its external structure is as follows Figure 1 shown. Example 2

[0033] A method for preparing a high-frequency, low-loss, three-dimensional shielding material comprises the following steps:

[0034] (1) The composition is Fe 73.5 Cu1Nb3Si 15.5 The iron-based amorphous alloy with a content of B7 (at.%) was prepared into spherical powder with a D50 particle size of 0.02 mm by water-gas combined atomization, and then heated to 580 °C for annealing and crystallization treatment for 2.5 h to obtain nanocrystalline soft magnetic alloy powder.

[0035] (2) The obtained nanocrystalline soft magnetic alloy powder was mixed with spherical manganese zinc ferrite powder with a D50 particle size of 0.02 mm and a binder (low melting point glass and epoxy resin with a mass ratio of 1:2) and then molded at a pressure of 30 MPa and a temperature of 100°C for 0.5 seconds. The mass ratio of the nanocrystalline soft magnetic alloy powder, ferrite powder and binder was 100:15:3 to obtain a high-frequency low-loss three-dimensional shielding material. The schematic diagram of the appearance structure of the obtained three-dimensional shielding material is shown in the figure. Figure 1 shown. Example 3

[0036] A method for preparing a high-frequency, low-loss, three-dimensional shielding material comprises the following steps:

[0037] (1) The composition is Fe 73.5 Cu1Nb3Si 15.5 The iron-based amorphous alloy with a content of B7 (at.%) was prepared into spherical powder with a D50 particle size of 0.05 mm by water-gas combined atomization, and then heated to 550 °C for annealing and crystallization treatment for 3 h to obtain nanocrystalline soft magnetic alloy powder.

[0038] (2) The obtained nanocrystalline soft magnetic alloy powder was mixed with spherical nickel-zinc ferrite powder with a D50 particle size of 0.05 mm and a binder (low-melting-point glass and epoxy resin in a mass ratio of 1:2) and then molded at a pressure of 50 MPa and a temperature of 100°C for 1 second. The mass ratio of the nanocrystalline soft magnetic alloy powder, ferrite powder and binder was 100:10:3, and a high-frequency low-loss three-dimensional shielding material was obtained. The schematic diagram of the external structure of the obtained three-dimensional shielding material is shown in FIG. Figure 1 shown. Example 4

[0039] A method for preparing a high-frequency, low-loss, three-dimensional shielding material comprises the following steps:

[0040] (1) The composition is Fe 73.5 Cu1Nb3Si 15.5 The iron-based amorphous alloy with a content of B7 (at.%) was prepared into spherical powder with a D50 particle size of 0.02 mm by water-gas combined atomization, and then heated to 520 °C for annealing and crystallization treatment for 4 h to obtain nanocrystalline soft magnetic alloy powder.

[0041] (2) The obtained nanocrystalline soft magnetic alloy powder was mixed with spherical copper-zinc ferrite powder with a D50 particle size of 0.02 mm and a binder (low-melting-point glass and epoxy resin with a mass ratio of 1:2) and then molded at a pressure of 20 MPa and a temperature of 100°C for 2 seconds; the mass ratio of the nanocrystalline soft magnetic alloy powder, ferrite powder and binder was 100:1:3 to obtain a high-frequency low-loss three-dimensional shielding material. The schematic diagram of the appearance structure of the obtained three-dimensional shielding material is shown in the figure. Figure 1 shown. Example 5

[0042] A method for preparing a high-frequency, low-loss, three-dimensional shielding material comprises the following steps:

[0043] (1) The composition is Fe 73.5 Cu1Nb3Si 15.5 The alloy with a B7 (at.%) content was prepared by single-roll rapid quenching into an initially amorphous alloy ribbon with a thickness of 20 μm. The ribbon was then mechanically crushed and sieved to produce a flaky powder with a thickness of 0.02 mm and a size of 0.1 mm. This was then heated to 580°C for 2.5 hours for annealing and crystallization, resulting in a nanocrystalline soft magnetic alloy powder.

[0044] (2) The obtained nanocrystalline soft magnetic alloy powder was mixed with spherical manganese zinc ferrite powder with a D50 particle size of 0.02 mm and a binder (low melting point glass and epoxy resin with a mass ratio of 1:2) and then molded at a pressure of 30 MPa and a temperature of 100°C for 0.5 seconds. The mass ratio of the nanocrystalline soft magnetic alloy powder, ferrite powder and binder was 100:15:3 to obtain a high-frequency low-loss three-dimensional shielding material. The schematic diagram of the appearance structure of the obtained three-dimensional shielding material is shown in the figure. Figure 1 shown.

[0045] Comparative Example 1

[0046] A method for preparing a high-frequency, low-loss, three-dimensional shielding material comprises the following steps:

[0047] Spherical manganese zinc ferrite powder with a D50 particle size of 0.10 mm and a binder (low melting point glass and epoxy resin in a mass ratio of 1:2) were mixed and then compression molded at a pressure of 30 MPa, a temperature of 100°C, and a holding pressure of 0.5 s. The mass ratio of manganese zinc ferrite powder to binder was 115:3, resulting in a high-frequency, low-loss three-dimensional shielding material. The schematic diagram of the appearance structure of the obtained three-dimensional shielding material is shown in the figure. Figure 1 shown.

[0048] Comparative Example 2

[0049] A method for preparing a high-frequency, low-loss, three-dimensional shielding material comprises the following steps:

[0050] (1) The composition is Fe 73.5 Cu1Nb3Si 15.5 The iron-based amorphous alloy with a content of B7 (at.%) was prepared into spherical powder with a D50 particle size of 0.10 mm by water-gas combined atomization, and then heated to 580 °C for annealing and crystallization treatment for 2.5 h to obtain nanocrystalline soft magnetic alloy powder.

[0051] (2) The obtained nanocrystalline soft magnetic alloy powder is mixed with a binder (low melting point glass and epoxy resin in a mass ratio of 1:2) and then molded at a pressure of 30 MPa, a temperature of 100°C, and a holding pressure of 0.5 s; the mass ratio of the nanocrystalline soft magnetic alloy powder and the binder is 115:3, and a high-frequency low-loss three-dimensional shielding material is obtained. The schematic diagram of the appearance structure of the obtained three-dimensional shielding material is shown in FIG. Figure 1 shown.

[0052] Comparative Example 3

[0053] A method for preparing a layered nanocrystalline shielding material comprises the following steps:

[0054] (1) The composition is Fe 73.5 Cu1Nb3Si 15.5 The alloy with a B7 (at.%) content was prepared by single-roll rapid quenching into an initially amorphous alloy ribbon with a thickness of 20 μm. The resulting amorphous alloy ribbon was then heated to 580°C and annealed for 2.5 hours to obtain a single-layer nanocrystalline ribbon.

[0055] (2) The annealed single-layer nanocrystalline ribbon is stacked in two layers, and the two layers are fixed by double-sided adhesive without substrate. The outermost layer is protected by double-sided adhesive coating without substrate, and the thickness of the double-sided adhesive is 2μm. The double-sided coated double-layer nanocrystalline ribbon is subjected to magnetic crushing treatment, and then the double-layer nanocrystalline ribbon after magnetic crushing treatment is multi-layered to obtain a nanocrystalline magnetic isolation sheet with the same main body thickness as the three-dimensional shielding material coil bonding area in Example 1. The schematic diagram of the external structure of the obtained nanocrystalline magnetic isolation sheet is shown as follows: Figure 2 shown.

[0056] The saturation magnetic induction intensity Bs of the shielding materials obtained in Examples 1 to 5 and Comparative Examples 1 to 3, as well as the inductance Ls, induction resistance Rs and quality factor Q value at different frequencies after bonding with the induction coil were measured. The results are shown in Table 1 below.

[0057] Table 1

[0058]

[0059] From the comparison results of the above Examples 1 to 4 and Comparative Examples 1 to 2, it can be seen that the three-dimensional shielding material of the present invention, through the combination of nanocrystalline soft magnetic alloy powder and ferrite powder, has a significantly lower corresponding induction resistance Rs value and a significantly improved quality factor Q value compared to simple ferrite powder and nanocrystalline soft magnetic alloy powder. This shows that the combination of nanocrystalline soft magnetic alloy powder and ferrite powder can significantly reduce high-frequency loss. From the comparison results of Comparative Example 2 and Comparative Example 3, it can be seen that the three-dimensional shielding material of the present invention can effectively reduce the leakage flux in the XY direction, reduce the leakage flux loss, and improve the power conversion efficiency compared to conventional layered nanocrystalline shielding materials. From the comparison results of Example 5 and Examples 1 to 2, it can be seen that the composite of flaky nanocrystalline soft magnetic alloy powder and spherical ferrite powder can more effectively block the eddy current path between nanocrystalline soft magnetic alloy particles and better couple the magnetic field between nanocrystalline soft magnetic alloy particles compared to simple spherical powder composite, thereby further reducing the loss and achieving better high-frequency magnetic properties.

[0060] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a high-frequency, low-loss, three-dimensional shielding material, characterized in that: The method comprises the following preparation steps: (1) The composition is Fe bal. M a Cu b M' c Si d B e X f The iron-based nanocrystalline and / or amorphous material is crushed and then annealed and crystallized to obtain nanocrystalline soft magnetic alloy powder; wherein M is Co and / or Ni, M' is at least one of Nb, V, Ta, and Mo, and X is at least one of common impurity elements such as C, O, N, S, and P; a=0-15%, b=0.5-1.5%, c=2-4%, d=12-17%, e=5-8%, and f=0-0.5%; (2) mixing the obtained nanocrystalline soft magnetic alloy powder with ferrite powder and a binder and then performing compression molding to obtain a high-frequency, low-loss three-dimensional shielding material; The crushing in step (1) refers to mechanically crushing the iron-based nanocrystalline and / or amorphous strip into flaky powders with a thickness of 0.005-0.03 mm and a size of 0.05-0.5 mm; The ferrite in step (2) is one or more of manganese zinc ferrite, nickel zinc ferrite and copper zinc ferrite; the ferrite powder is spherical powder with a D50 particle size of 0.003-0.100 mm; The adhesive in step (2) is one or more of epoxy resin, low melting point glass, acrylic resin, silicone rubber, and polyurethane; The mass ratio of the nanocrystalline soft magnetic alloy powder, ferrite powder and binder mixed in step (2) is 100:1~30:1~10; The compression molding in step (2) is performed at a pressure of 5 to 500 MPa, a temperature of 25 to 200° C., and a time of 0.2 to 3 s.

2. The method for preparing a high-frequency low-loss three-dimensional shielding material according to claim 1, characterized in that: The temperature of the annealing crystallization treatment in step (1) is 500~620℃, and the time is 0.5~4h.

3. A high-frequency, low-loss, three-dimensional shielding material, characterized in that: It is prepared by the method according to claim 1 or 2.

4. The high-frequency, low-loss, three-dimensional shielding material according to claim 3, characterized in that: A coil fitting area is provided on one side of the three-dimensional shielding material, and the outer periphery and inner periphery of the coil fitting area have convex parts perpendicular to the coil plane.

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