Low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor and preparation method thereof

Abstract

The present invention belongs to the technical field of soft magnetic composite materials, and specifically provides a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors and a preparation method thereof, aiming to solve the problems of high magnetic loss, high dielectric loss, and low saturation magnetization intensity of existing soft magnetic composite materials in the ultra-high frequency band. The soft magnetic composite material in the present invention comprises components: spherical iron-based nanocrystalline magnetic powder: 96-99.5 wt%, ZnO or B2O3 oxide: 0.5-4 wt%; the ZnO or B2O3 oxide is used as an insulating coating material. The present invention uses ZnO or B2O3 to conduct insulating coating on the spherical iron-based nanocrystalline magnetic powder, and obtains a dense soft magnetic composite material through a cold sintering process and annealing treatment, which has a high relative density, a high saturation magnetization intensity, and low magnetoelectric loss, and raises the permeability cut-off frequency to the 1.5-5 GHz band, meeting the application requirements of the ultra-high frequency band.

Description

Technical Field

[0001] The present invention belongs to the technical field of soft magnetic composite materials, relates to soft magnetic composite materials for ultra-high frequency inductors and preparation thereof, and specifically provides a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors and a preparation method thereof. Background Art

[0002] With the rapid development of communication technology, Internet of Things, aerospace and new energy vehicles, the corresponding power electronic devices are constantly updated and iterated, and electromagnetic components are constantly developing in the direction of miniaturization, high efficiency, high frequency and high power, which poses great challenges to the application frequency and comprehensive performance of soft magnetic composite materials. For example, the common mode choke can act as a low impedance component of the primary signal and a high impedance inductor of high frequency noise to provide protection for the system, but the soft magnetic material in the common mode choke is required to have a high magnetic permeability in the MHz to GHz frequency band to minimize the impact of electromagnetic interference, and a high resistivity to minimize the unnecessary loss caused by high frequency harmonics; however, due to the high eddy current loss and low high frequency magnetic permeability, the application frequency of soft magnetic composite materials is still limited to below 1MHz, such as the patent documents with publication numbers CN109273185A, CN106890999A, CN103559974A, CN102744403A, etc.; therefore, it is urgent to develop new soft magnetic composite materials with high working frequency and excellent magnetoelectric properties.

[0003] Amorphous / nanocrystalline soft magnetic alloy crushed magnetic powder is usually irregular in shape. Compared with spherical alloy powder, irregular powder has a larger contact area during the pressing process, better pressing formability, and higher density and magnetic permeability of the soft magnetic composite material. In comparison, the soft magnetic alloy powder prepared by the water-gas combined atomization method is mainly in the shape of a small sphere. Its advantage is that the specific surface area and surface energy are relatively large, which is conducive to obtaining a uniform and complete insulating coating layer, thereby improving the high-frequency magnetoelectric properties of the soft magnetic composite material. However, after cold pressing of the alloy spherical powder, there are many holes and gaps between the particles, and the mechanical strength of the obtained soft magnetic composite material is low. It is often necessary to add a higher volume fraction of organic resin to improve the mechanical strength and reliability of the soft magnetic composite material, but most organic polymers will reduce the high-temperature stability of the soft magnetic composite material.

[0004] Cold sintering technology can prepare high-density, high-resistivity soft magnetic composite materials under mild pressure and temperature conditions, effectively improve the application frequency and comprehensive performance of soft magnetic composite materials, so that they have good application prospects in the fields of high-frequency inductors, DC-DC converters, chokes and high-frequency switching power supplies; For example, the patent document with publication number CN110428967A discloses a method and product for preparing an ultra-low temperature cold-sintered iron-based nanocrystalline composite magnetic powder core, firstly, a nano-ferrite precursor is coated on the surface of the iron-based nanocrystalline magnetic powder, and then a nano-composite magnetic powder core embryo is obtained by cold sintering, and finally, an iron-based nanocrystalline composite magnetic powder core with high density and excellent soft magnetic properties is prepared by annealing, and the stable frequency band of magnetic permeability is increased to the GHz band, which can reach 854.8MHz, but it still has problems such as high magnetic loss and dielectric loss and low saturation magnetization in the ultra-high frequency band, which cannot meet the application requirements of the ultra-high frequency band. Therefore, the present invention further proposes a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors and a preparation method thereof. Summary of the invention

[0005] The purpose of the present invention is to provide a low magnetic-dielectric loss soft magnetic composite material for ultra-high frequency inductors and a preparation method thereof, in view of the problems that existing soft magnetic composite materials have high magnetic loss and dielectric loss, low saturation magnetization intensity, etc. in the ultra-high frequency band. Spherical iron-based nanocrystalline magnetic powder is insulated and coated with ZnO or B2O3, and a dense and high-resistivity soft magnetic composite material is obtained through a cold sintering process and annealing treatment, and its magnetic permeability cutoff frequency is increased to the 1.5-5GHz frequency band to meet the application requirements of the ultra-high frequency band and improve its magnetoelectric performance in the ultra-high frequency band.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors, the soft magnetic composite material comprising the following components (measured by weight percentage):

[0008] Spherical iron-based nanocrystalline magnetic powder: 96-99.5wt%,

[0009] ZnO or B2O3 oxide: 0.5-4wt%;

[0010] Among them, ZnO or B2O3 oxide is used as the insulating coating material.

[0011] Furthermore, the particle size of the spherical iron-based nanocrystalline magnetic powder is less than or equal to 5 microns.

[0012] Furthermore, the method for preparing the low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor comprises the following steps:

[0013] Step 1. Screening the particle size of spherical iron-based nanocrystalline magnetic powder to obtain spherical iron-based nanocrystalline magnetic powder raw material;

[0014] Step 2. Using ZnO or B2O3 oxide as the insulating coating material, weighing the spherical iron-based nanocrystalline magnetic powder raw material and the insulating coating material according to the component content, and coating the surface of the spherical iron-based nanocrystalline magnetic powder by a sol-gel method to obtain a coating material;

[0015] Step 3. According to the ratio of the liquid medium to the coating material of 10 to 30 wt%, the liquid medium and the coating material are evenly mixed, and then the mixture is sintered at 200 to 800 MPa and 100 to 300 ° C for 0.5 to 3 h to obtain a soft magnetic composite material embryo;

[0016] Step 4: annealing the soft magnetic composite material embryo in an inert atmosphere at 400-600° C. for 0.5-2 hours to obtain a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors.

[0017] Furthermore, in step 1, the spherical iron-based nanocrystalline magnetic powder is at least one of FeSiBPCuCCr alloy powder, FeSiBPCu alloy powder, and FeSiBNbCu alloy powder.

[0018] Furthermore, in step 1, the particle size screening uses a 2500-mesh sieve.

[0019] Furthermore, in step 2, the sol-gel method is specifically:

[0020] The spherical iron-based nanocrystalline magnetic powder raw material is dispersed in a mixed solution of zinc alum (ZnSO4·7H2O) and sodium citrate, or in a mixed solution of boric acid (HBO3) and sodium citrate; after being stirred evenly, the pH value is adjusted to 9-11, and then the material is allowed to stand in a water bath at 40-80°C until it reaches a sol state, the sol product is dried to a gel state, and the gel product is heat-treated in an inert atmosphere at 400-550°C for 0.5-2h to obtain a coating material.

[0021] Furthermore, in step 3, the liquid medium is water, aqueous ammonia, acetic acid or acetic acid.

[0022] Furthermore, in step 4, the inert atmosphere is argon or nitrogen.

[0023] Based on the above technical solution, the beneficial effects of the present invention are:

[0024] The present invention first selects spherical iron-based nanocrystalline magnetic powder with fine particle size, coats ZnO or B2O3 oxide on the surface thereof, and then adds a predetermined amount of liquid medium, so that the coating material is partially dissolved and reprecipitated on the surface of the magnetic powder particles during the cold sintering molding process, so as to obtain a dense soft magnetic composite material; the selection of spherical iron-based nanocrystalline magnetic powder with fine particle size is conducive to obtaining an insulating film with uniform distribution and complete coating; ZnO or B2O3 is used as the insulating coating material, the coating process is simple, and the thickness of the insulating film can be effectively controlled by increasing or decreasing the content; the cold sintering technology requires a relatively small molding pressure, which not only improves the relative density of the soft magnetic composite material, but also greatly reduces the damage of the insulating coating film, thereby improving the ultra-high frequency magnetoelectric properties of the soft magnetic composite material; in addition, annealing the soft magnetic composite embryo can remove the residual stress caused by pressing.

[0025] In summary, the present invention provides a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors, which has a high relative density, a high saturation magnetization intensity and a low magnetoelectric loss, and increases the magnetic permeability cutoff frequency to 1.5 to 5 GHz, which can meet the application requirements of ultra-high frequency inductors and is suitable for promotion and use in this field. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a cross-sectional scanning electron microscope image of the soft magnetic composite material prepared in Example 2.

[0027] Figure 2 This is a curve diagram showing the variation of the real part of the magnetic permeability and the magnetic loss tangent of the soft magnetic composite material prepared in Example 2 with the frequency.

[0028] Figure 3 This is a curve chart showing the change of the real part of the magnetic permeability and the magnetic loss tangent of the soft magnetic composite material prepared in Example 17 with frequency.

[0029] Figure 4 This is a curve diagram of the change of the real part of the dielectric constant and the dielectric loss tangent of the soft magnetic composite material prepared in Example 2 with frequency.

[0030] Figure 5 This is a curve chart showing the variation of the real part of the dielectric constant and the dielectric loss tangent of the soft magnetic composite material prepared in Example 17 with frequency. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0032] Embodiment 1~5:

[0033] The low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor provided in Examples 1 to 5 comprises spherical FeSiBPCuCCr iron-based nanocrystalline magnetic powder and ZnO oxide, and the component contents are shown in Table 1; the soft magnetic composite material is prepared by the following steps:

[0034] Step 1. Using a 2500-mesh sieve to screen the particle size of the spherical iron-based nanocrystalline magnetic powder to obtain a spherical iron-based nanocrystalline magnetic powder raw material;

[0035] Step 2. Taking ZnO oxide as the insulating coating material, weighing the spherical iron-based nanocrystalline magnetic powder raw material and the insulating coating material according to the component contents shown in Table 1, and surface coating the spherical iron-based nanocrystalline magnetic powder by a sol-gel method to obtain a coating material; specifically, dispersing the spherical iron-based nanocrystalline magnetic powder raw material in a mixed solution of zinc alum (ZnSO4·7H2O) and sodium citrate (the molar ratio of Na ions to Zn ions is 2:1), stirring evenly, adjusting the pH value to 10, and continuing to stir for 0.5h, and then standing for 2h in a 65°C water bath to form a sol state, drying the sol product for 4h to form a gel state, and heat-treating the gel product at 450°C in an inert atmosphere for 2h to obtain a coating material;

[0036] Step 3. According to the ratio of liquid medium to coating material of 15wt%, deionized water and coating material are mixed evenly, and then the mixture is put into a mold, a pressure of 300MPa is applied to the mold, and cold sintered at 180℃ for 1.5h under the pressure to form a soft magnetic composite material embryo;

[0037] Step 4. Anneal the soft magnetic composite material embryo in an argon atmosphere at 475° C. for 1 hour to obtain a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors.

[0038] Table 1

[0039] Example 1 Example 2 Example 3 Example 4 Example 5 FeSiBPCuCCr 99.5wt% 99.0wt% 98.0wt% 97.0wt% 96.0wt% ZnO 0.5wt% 1.0wt% 2.0wt% 3.0wt% 4.0wt%

[0040] Embodiment 6~10:

[0041] The low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor provided in Examples 6 to 10 comprises spherical FeSiBPCu iron-based nanocrystalline magnetic powder and ZnO oxide, and the component contents are shown in Table 2; the soft magnetic composite material is prepared by the following steps:

[0042] Step 1. Using a 2500-mesh sieve to screen the particle size of the spherical iron-based nanocrystalline magnetic powder to obtain a spherical iron-based nanocrystalline magnetic powder raw material;

[0043] Step 2. Taking ZnO oxide as the insulating coating material, weighing the spherical iron-based nanocrystalline magnetic powder raw material and the insulating coating material according to the component contents shown in Table 1, and surface coating the spherical iron-based nanocrystalline magnetic powder by a sol-gel method to obtain a coating material; specifically, dispersing the spherical iron-based nanocrystalline magnetic powder raw material in a mixed solution of zinc alum (ZnSO4·7H2O) and sodium citrate (the molar ratio of Na ion to Zn ion is 2:1), stirring evenly and adjusting the pH value to 11, and continuing to stir for 0.5h, and then standing for 2h in a water bath at 80°C to form a sol state, drying the sol product for 4h to form a gel state, and heat-treating the gel product at 500°C in an inert atmosphere for 2h to obtain a coating material;

[0044] Step 3. According to the ratio of liquid medium to coating material, acetic acid and coating material are evenly mixed, and then the mixture is put into a mold, a pressure of 500MPa is applied to the mold, and cold sintered at 150°C for 2h under the pressure to form a soft magnetic composite material embryo;

[0045] Step 4. Anneal the soft magnetic composite material embryo in an argon atmosphere at 550° C. for 1 hour to obtain a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors.

[0046] Table 2

[0047] Example 6 Example 7 Example 8 Example 9 Example 10 FeSiBPCu 99.5wt% 99.0wt% 98.0wt% 97.0wt% 96.0wt% ZnO 0.5wt% 1.0wt% 2.0wt% 3.0wt% 4.0wt%

[0048] Embodiments 11 to 15:

[0049] The low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor provided in Examples 11 to 15 comprises spherical FeSiBNbCu iron-based nanocrystalline magnetic powder and ZnO oxide, and the component contents are shown in Table 3; the soft magnetic composite material is prepared by the following steps:

[0050] Step 1. Using a 2500-mesh sieve to screen the particle size of the spherical iron-based nanocrystalline magnetic powder to obtain a spherical iron-based nanocrystalline magnetic powder raw material;

[0051] Step 2. Using ZnO oxide as the insulating coating material, weighing the spherical iron-based nanocrystalline magnetic powder raw material and the insulating coating material according to the component contents shown in Table 3, and surface coating the spherical iron-based nanocrystalline magnetic powder by a sol-gel method to obtain a coating material; specifically, dispersing the spherical iron-based nanocrystalline magnetic powder raw material in a mixed solution of zinc alum (ZnSO4·7H2O) and sodium citrate (the molar ratio of Na ions to Zn ions is 2:1), stirring evenly and adjusting the pH value to 9.5, and continuing to stir for 0.5h, and then standing for 2h in a 70°C water bath to form a sol state, drying the sol product for 4h to form a gel state, and heat-treating the gel product at 500°C in an inert atmosphere for 1h to obtain a coating material;

[0052] Step 3. According to the ratio of liquid medium to coating material 30wt%, ammonia water and coating material are mixed evenly, and then the mixture is put into a mold, a pressure of 600MPa is applied to the mold, and cold sintered at 160°C for 1h under the pressure to form a soft magnetic composite material embryo;

[0053] Step 4. Anneal the soft magnetic composite material embryo in an argon atmosphere at 500° C. for 1.5 hours to obtain a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors.

[0054] Table 3

[0055]

[0056]

[0057] Embodiments 16 to 20:

[0058] The low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor provided in Examples 16 to 20 comprises spherical FeSiBPCuCCr iron-based nanocrystalline magnetic powder and B2O3 oxide, and the component contents are shown in Table 4; the soft magnetic composite material is prepared by the following steps:

[0059] Step 1. Using a 2500-mesh sieve to screen the particle size of the spherical iron-based nanocrystalline magnetic powder to obtain a spherical iron-based nanocrystalline magnetic powder raw material;

[0060] Step 2. Using B2O3 oxide as the insulating coating material, weighing the spherical iron-based nanocrystalline magnetic powder raw material and the insulating coating material according to the component contents shown in Table 4, and surface coating the spherical iron-based nanocrystalline magnetic powder by a sol-gel method to obtain a coating material; specifically, dispersing the spherical iron-based nanocrystalline magnetic powder raw material in a mixed solution of boric acid (HBO3) and sodium citrate (the molar ratio of Na ions to B ions is 3:1), stirring evenly and adjusting the pH value to 10, and continuing to stir for 0.5h, and then standing for 2h in a 65°C water bath to form a sol state, drying the sol product for 4h to form a gel state, and heat-treating the gel product at 450°C in an inert atmosphere for 2h to obtain a coating material;

[0061] Step 3. According to the ratio of liquid medium to coating material of 15wt%, deionized water and coating material are mixed evenly, and then the mixture is put into a mold, a pressure of 300MPa is applied to the mold, and cold sintered at 180℃ for 1.5h under the pressure to form a soft magnetic composite material embryo;

[0062] Step 4. Anneal the soft magnetic composite material embryo in an argon atmosphere at 475° C. for 1 hour to obtain a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors.

[0063] Table 4

[0064] Example 16 Embodiment 17 Embodiment 18 Embodiment 19 Embodiment 20 FeSiBPCuCCr 99.5wt% 99.0wt% 98.0wt% 97.0wt% 96.0wt% <![CDATA[B2O3]]> 0.5wt% 1.0wt% 2.0wt% 3.0wt% 4.0wt%

[0065] Embodiments 21 to 25:

[0066] The low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor provided in Examples 21 to 25 comprises spherical FeSiBPCu iron-based nanocrystalline magnetic powder and B2O3 oxide, and the component contents are shown in Table 5; the soft magnetic composite material is prepared by the following steps:

[0067] Step 1. Using a 2500-mesh sieve to screen the particle size of the spherical iron-based nanocrystalline magnetic powder to obtain a spherical iron-based nanocrystalline magnetic powder raw material;

[0068] Step 2. Using B2O3 oxide as the insulating coating material, weighing the spherical iron-based nanocrystalline magnetic powder raw material and the insulating coating material according to the component contents shown in Table 5, and using the sol-gel method to coat the surface of the spherical iron-based nanocrystalline magnetic powder to obtain a coating material; specifically, dispersing the spherical iron-based nanocrystalline magnetic powder raw material in a mixed solution of boric acid (HBO3) and sodium citrate (the molar ratio of Na ions to B ions is 3:1), stirring evenly and adjusting the pH value to 10.5, and continuing to stir for 0.5h, and then standing in a 60°C water bath for 2h to form a sol state, drying the sol product for 4h to form a gel state, and heat-treating the gel product at 400°C in an inert atmosphere for 2h to obtain a coating material;

[0069] Step 3. According to the ratio of liquid medium to coating material of 15wt%, acetic acid and coating material are mixed evenly, and then the mixture is put into a mold, a pressure of 700MPa is applied to the mold, and cold sintered at 150°C for 1h under the pressure to form a soft magnetic composite material embryo;

[0070] Step 4. Anneal the soft magnetic composite material embryo in an argon atmosphere at 500° C. for 1 hour to obtain a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors.

[0071] Table 5

[0072] Embodiment 21 Embodiment 22 Embodiment 23 Embodiment 24 Embodiment 25 FeSiBPCu 99.5wt% 99.0wt% 98.0wt% 97.0wt% 96.0wt% <![CDATA[B2O3]]> 0.5wt% 1.0wt% 2.0wt% 3.0wt% 4.0wt%

[0073] Embodiments 26 to 30:

[0074] The low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor provided in Examples 26 to 30 comprises spherical FeSiBNbCu iron-based nanocrystalline magnetic powder and B2O3 oxide, and the component contents are shown in Table 6; the soft magnetic composite material is prepared by the following steps:

[0075] Step 1. Using a 2500-mesh sieve to screen the particle size of the spherical iron-based nanocrystalline magnetic powder to obtain a spherical iron-based nanocrystalline magnetic powder raw material;

[0076] Step 2. Using B2O3 oxide as the insulating coating material, weighing the spherical iron-based nanocrystalline magnetic powder raw material and the insulating coating material according to the component contents shown in Table 5, and using the sol-gel method to coat the surface of the spherical iron-based nanocrystalline magnetic powder to obtain a coating material; specifically, dispersing the spherical iron-based nanocrystalline magnetic powder raw material in a mixed solution of boric acid (HBO3) and sodium citrate (the molar ratio of Na ions to B ions is 3:1), stirring evenly and adjusting the pH value to 11, and continuing to stir for 0.5h, and then standing in a 50°C water bath for 2h to form a sol state, drying the sol product for 4h to form a gel state, and heat-treating the gel product at 500°C in an inert atmosphere for 1h to obtain a coating material;

[0077] Step 3. According to the ratio of liquid medium to coating material 20wt%, deionized water and coating material are mixed evenly, and then the mixture is put into a mold, a pressure of 600MPa is applied to the mold, and cold sintered at 160°C for 1.5h under the pressure to form a soft magnetic composite material embryo;

[0078] Step 4. Anneal the soft magnetic composite material embryo in an argon atmosphere at 450° C. for 2 hours to obtain a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors.

[0079] Table 6

[0080] Embodiment 26 Embodiment 27 Embodiment 28 Embodiment 29 Embodiment 30 FeSiBNbCu 99.5wt% 99.0wt% 98.0wt% 97.0wt% 96.0wt% <![CDATA[B2O3]]> 0.5wt% 1.0wt% 2.0wt% 3.0wt% 4.0wt%

[0081] The low magnetic dielectric loss soft magnetic composite materials for ultra-high frequency inductors prepared in the above-mentioned embodiments 1 to 30 are simulated and tested. For example, Figure 1 The following is a cross-sectional SEM image of the soft magnetic composite material prepared in Example 2. Figure 2 The graph shown is a curve of the real part of the magnetic permeability and the magnetic loss tangent of the soft magnetic composite material prepared in Example 2 as a function of frequency. Figure 3 The graph shown is a curve of the real part of the magnetic permeability and the magnetic loss tangent of the soft magnetic composite material prepared in Example 17 as a function of frequency. Figure 4 The graph shown is a curve of the real part of the dielectric constant and the dielectric loss tangent of the soft magnetic composite material prepared in Example 2 as a function of frequency. Figure 5 The graph shows the change of the real part of the dielectric constant and the dielectric loss tangent of the soft magnetic composite material prepared in Example 17 with the frequency; the performance results of the soft magnetic composite materials in Example 2, Example 4, Example 17 and Example 19 are shown in Table 7;

[0082] Table 7

[0083]

[0084] Among them, the magnetic permeability loss tangent tanδμ Dielectric loss tangent tanδ ε Based on the test results of the impedance analyzer (E4991B), according to the curve of the real and imaginary parts of the magnetic permeability changing with the frequency, the ratio of the imaginary part of the magnetic permeability to the real part of the magnetic permeability corresponding to the frequency of 1 GHz is taken as the permeability loss tangent value tanδ μ According to the curve of the real and imaginary parts of the dielectric constant changing with frequency, the ratio of the imaginary part of the dielectric constant to the real part of the dielectric constant corresponding to a frequency of 1 GHz is taken as the dielectric loss tangent tanδ ε .

[0085] Depend on Figure 1 to Figure 5 As can be seen from Table 7, the soft magnetic composite material successfully prepared by the cold sintering process has high density, high magnetic permeability, and low ultra-high frequency magnetoelectric loss characteristics, and the magnetic permeability cutoff frequency is increased to 1.5-5 GHz to meet the application requirements of the ultra-high frequency band.

[0086] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A low dielectric loss soft magnetic composite material for ultra-high frequency inductors, characterized in that: The soft magnetic composite material comprises the following components: Spherical FeSiBPCuCCr iron-based nanocrystalline magnetic powder: 97.0wt%, ZnO oxide: 3.0wt%, the particle size of the spherical FeSiBPCuCCr iron-based nanocrystalline magnetic powder is less than or equal to 5 microns, and the ZnO oxide is used as an insulating coating material; Alternatively, spherical FeSiBPCuCCr iron-based nanocrystalline magnetic powder: 99.0wt%, B2O3 oxide: 1.0wt%, the particle size of the spherical FeSiBPCuCCr iron-based nanocrystalline magnetic powder is less than or equal to 5 microns, and the B2O3 oxide is used as an insulating coating material; Alternatively, spherical FeSiBPCuCCr iron-based nanocrystalline magnetic powder: 97.0wt%, B2O3 oxide: 3.0wt%, the particle size of the spherical FeSiBPCuCCr iron-based nanocrystalline magnetic powder is less than or equal to 5 microns, and the B2O3 oxide is used as an insulating coating material.

2. The method for preparing the low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor according to claim 1, characterized in that: The following steps are involved: Step 1. Screening the particle size of spherical iron-based nanocrystalline magnetic powder to obtain spherical iron-based nanocrystalline magnetic powder raw material; Step 2. Using ZnO or B2O3 oxide as the insulating coating material, weighing the spherical iron-based nanocrystalline magnetic powder raw material and the insulating coating material according to the component content, and coating the surface of the spherical iron-based nanocrystalline magnetic powder by a sol-gel method to obtain a coating material; Step 3. According to the ratio of the liquid medium to the coating material of 10 to 30 wt%, the liquid medium and the coating material are evenly mixed, and then the mixture is sintered at 200 to 800 MPa and 100 to 300 ° C for 0.5 to 3 h to obtain a soft magnetic composite material embryo; Step 4: annealing the soft magnetic composite material embryo in an inert atmosphere at 400-600° C. for 0.5-2 hours to obtain a low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductors.

3. The method for preparing the low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor according to claim 2, characterized in that: In step 1, the spherical iron-based nanocrystalline magnetic powder adopts FeSiBPCuCCr alloy powder.

4. The method for preparing the low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor according to claim 2, characterized in that: In step 1, the particle size screening uses a 2500 mesh sieve.

5. The method for preparing the low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor according to claim 2, characterized in that: In step 2, the sol-gel method is specifically as follows: The spherical iron-based nanocrystalline magnetic powder raw material is dispersed in a mixed solution of zinc alum and sodium citrate, or in a mixed solution of boric acid and sodium citrate; after stirring evenly, the pH value is adjusted to 9-11, and then the mixture is allowed to stand in a water bath at 40-80°C until it reaches a sol state, the sol product is dried to a gel state, and the gel product is heat-treated in an inert atmosphere at 400-550°C for 0.5-2h to obtain a coating material.

6. The method for preparing the low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor according to claim 2, characterized in that: In step 3, the liquid medium is water, aqueous ammonia, acetic acid or acetic acid.

7. The method for preparing the low magnetic dielectric loss soft magnetic composite material for ultra-high frequency inductor according to claim 2, characterized in that: In step 4, the inert atmosphere is argon or nitrogen.

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