阅读说明：本技术 一种高频低损耗复合软磁材料及其制备方法和用途 (High-frequency low-loss composite soft magnetic material and preparation method and application thereof ) 是由 李玉平 李军华 孙永阳 孔佳元 蒋云涛 于 2020-12-21 设计创作，主要内容包括：本发明涉及一种高频低损耗复合软磁材料及其制备方法和用途,所述高频低损耗复合软磁材料包括金属磁粉和粘结剂,所述金属磁粉包括R-2M-xT-y；其中,R包括Ce,M包括Fe,T包括N,x和y分别为M和T的原子含量,x的范围为16-26,y的范围为2.5-3,所述金属磁粉的粒径D50为100-300nm且形状为近球形。本发明经过优化复合软磁材料中金属磁粉的成分组成和微观组织,并将其与绝缘性的粘结剂复合得到高频低损耗复合软磁材料,可以极大地降低涡流损耗,使其更适合在GHz条件下工作,截止频率为8.5-10.2GHz,在6GHz的频率下,磁导率μ’为1.2-2.2,磁损耗tanδμ为0.05-0.15。(The invention relates to a high-frequency low-loss composite soft magnetic material, a preparation method and application thereof 2 M x T y (ii) a Wherein R comprises Ce, M comprises Fe, T comprises N, x and y are the atomic contents of M and T respectively, x ranges from 16 to 26, y ranges from 2.5 to 3, the particle size D50 of the metal magnetic powder is 100-300nm and the shape of the metal magnetic powder is nearly spherical. The invention optimizes the composition and microstructure of the metal magnetic powder in the composite soft magnetic material, and compounds the metal magnetic powder with an insulating binder to obtain the high-frequency low-loss composite soft magnetic material, which can greatly reduce the eddy current loss and make the composite soft magnetic material more suitable for working under the GHz condition, wherein the cut-off frequency is 8.5-10.2GHz, the magnetic permeability mu' is 1.2-2.2 under the frequency of 6GHz, and the magnetic loss tan delta mu is 0.05-0.15.)

1. A high-frequency low-loss composite soft magnetic material is characterized by comprising metal magnetic powder and a binder, wherein the metal magnetic powder comprises R₂M_xT_y(ii) a Wherein R comprises Ce, M comprises Fe, T comprises N, x and y are the atomic contents of M and T respectively, x ranges from 16 to 26, y ranges from 2.5 to 3, the particle size D50 of the metal magnetic powder is 100-300nm and the shape of the metal magnetic powder is nearly spherical.

2. The high-frequency low-loss composite soft magnetic material according to claim 1, wherein in the metal magnetic powder, R further comprises any one or a combination of at least two of Sm, Nd, Pr or Ho;

preferably, in the metal magnetic powder, M further includes Co and/or Ni;

preferably, in the metal magnetic powder, T also comprises H and/or O;

preferably, the metal magnetic powder is surface-modified;

preferably, the surface modification comprises forming a passivation layer on the surface and/or coating a coupling agent on the surface;

preferably, the coupling agent comprises any one of a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent, or a combination of at least two thereof.

3. The high frequency low loss composite soft magnetic material according to claim 1 or 2, wherein the binder comprises any one or a combination of at least two of paraffin wax, epoxy resin, nylon or polyvinyl alcohol;

preferably, in the high-frequency low-loss composite soft magnetic material, the mass of the binder is 5-40% of that of the metal magnetic powder;

preferably, the binder is coated on the surface of the metal magnetic powder;

preferably, the high-frequency low-loss composite soft magnetic material is granular.

4. A method for preparing a high-frequency low-loss composite soft magnetic material according to any one of claims 1 to 3, wherein the preparation method comprises the following steps:

(1) preparing metal magnetic powder comprising R₂M_xT_y(ii) a Wherein R comprises Ce, M comprises Fe, T comprises N, x and y are the atomic contents of M and T respectively, the range of x is 16-26, and the range of y is 2.5-3;

(2) and (2) mixing the metal magnetic powder obtained in the step (1) with a binder according to a formula amount, and processing to obtain the high-frequency low-loss composite soft magnetic material.

5. The method according to claim 4, wherein the method of manufacturing the metal magnetic powder of step (1) comprises the steps of:

(i) according to R₂M_xWeighing the acetylacetone compound of R and the acetylacetone compound of M, adding the weighed acetylacetone compounds into an organic solvent, uniformly mixing, and then adding calcium acetylacetonate for full stirring;

(ii) (ii) subjecting the liquid mixture obtained in step (i) to a thermal decomposition treatment to obtain a solid mixture;

(iii) and (iii) sequentially carrying out reduction treatment, nitridation treatment and cleaning treatment on the solid mixture obtained in the step (ii) to obtain the metal magnetic powder.

6. The method according to claim 5, wherein the organic solvent of step (i) is oleylamine;

preferably, the mass of calcium acetylacetonate in step (i) is 10-80% of the sum of the mass of R acetylacetonate and M acetylacetonate;

preferably, the temperature of the thermal decomposition treatment in step (ii) is 150-;

preferably, the time of the thermal decomposition treatment in the step (ii) is 4-6 h;

preferably, the reducing agent used in the reduction treatment of step (iii) is metallic calcium;

preferably, the reduction treatment of step (iii) is performed under the protection of argon;

preferably, the temperature of the reduction treatment in step (iii) is 850-;

preferably, the holding time of the reduction treatment in step (iii) is 30-60 min;

preferably, the nitriding treatment of step (iii) is carried out in an ammonia atmosphere;

preferably, the temperature of the nitriding treatment in step (iii) is 400-;

preferably, the heat preservation time of the nitridation treatment in the step (iii) is 3-5 h;

preferably, the washing treatment of step (iii) comprises a deionized water washing and an ethanol filtering washing which are sequentially carried out.

7. The method according to any one of claims 4 to 6, wherein before the mixing of the metal magnetic powder with the binder in step (2), the method further comprises performing surface passivation and surface coating on the metal magnetic powder in sequence to obtain a surface-modified metal magnetic powder;

preferably, the passivating agent adopted for the surface passivation treatment is a phosphoric acid solution;

preferably, the mass of the phosphoric acid in the phosphoric acid solution is 0.5-1% of the mass of the metal magnetic powder;

preferably, the coupling agent used for the surface coating treatment comprises any one or a combination of at least two of a silane coupling agent, a titanate coupling agent or an aluminate coupling agent;

preferably, the mass of the coupling agent is 0.5-1% of the mass of the metal magnetic powder.

8. The production method according to any one of claims 4 to 7, wherein the mass of the binder in the step (2) is 5 to 40% of the mass of the metal magnetic powder;

preferably, the processing treatment in step (2) includes: and putting the mixture of the metal magnetic powder and the binder into a double-screw granulator, mixing under the protection of nitrogen to obtain a rubber-magnetic mixture, and then cutting the rubber-magnetic mixture into particles by using a granulator.

9. The method according to any one of claims 4 to 8, characterized by comprising the steps of:

(1) preparing metal magnetic powder comprising R₂M_xT_y(ii) a Wherein R comprises Ce, M comprises Fe, T comprises N, x and y are the atomic contents of M and T respectively, the range of x is 16-26, and the range of y is 2.5-3;

(i) according to R₂M_xWeighing the acetylacetone compound of R and the acetylacetone compound of M, adding into oleylamine, mixing uniformly, and adding calcium acetylacetonate for full stirring; the mass of the calcium acetylacetonate is 10-80% of the sum of the mass of the acetylacetonate of R and the acetylacetonate of M;

(ii) (ii) subjecting the liquid mixture obtained in the step (i) to heating decomposition treatment at the temperature of 150 ℃ and 250 ℃ for 4-6h to obtain a solid mixture;

(iii) adding metal calcium into the solid mixture obtained in the step (ii), heating to 850-plus 900 ℃ under the protection of argon, preserving heat for 30-60min for reduction treatment, then cooling to 400-plus 500 ℃, extracting argon, filling ammonia gas, preserving heat for 3-5h, performing nitridation treatment under the atmosphere of ammonia gas, then cooling to room temperature, firstly performing reverse deionized water cleaning, and then performing ethanol filtering and washing to obtain the metal magnetic powder;

(2) adding the metal magnetic powder in the step (1) into a phosphoric acid solution, repeatedly stirring the phosphoric acid solution under the protection of nitrogen to perform surface passivation treatment, then adding a coupling agent to perform surface coating treatment, wherein the mass of the coupling agent is 0.5-1% of that of the metal magnetic powder, then mixing the coupling agent with a binder, the mass of the binder is 5-40% of that of the metal magnetic powder, putting the mixture of the metal magnetic powder and the binder into a double-screw granulator, mixing the mixture under the protection of nitrogen to obtain a rubber-magnetic mixture, and then cutting the rubber-magnetic mixture into particles by using a granulator to obtain the high-frequency low-loss composite soft magnetic material.

10. Use of the high-frequency low-loss composite soft magnetic material according to any one of claims 1 to 3, wherein the high-frequency low-loss composite soft magnetic material is used for preparing wave-absorbing, inductance and radio-frequency devices.

Technical Field

The invention relates to the technical field of magnetic materials, in particular to a high-frequency low-loss composite soft magnetic material and a preparation method and application thereof.

Background

Soft magnetic materials and their components (inductors, transformers, motors, etc.) play a very important role in the industrial society as core components for the transformation of energy conveyors. In recent years, with the development of technology, Wide Bandgap Semiconductors (WBGs) have been introduced to allow various electronic components to operate at higher frequencies, thereby reducing the size of the devices and improving the energy efficiency of the system. However, as the operating frequency increases, the eddy current loss of the device increases sharply, which not only reduces the energy efficiency of the device, but also causes the device to generate heat seriously. For electronic components, the technical development of soft magnetic materials is far behind that of wide bandgap semiconductors (WBG), which becomes a bottleneck limiting the use of electronic devices at high frequencies. Particularly, with the advent of the 5G era and the rise of the research on the 6G technology, electronic devices are increasingly developed to high frequency and miniaturization, and the market urgently requires a soft magnetic material capable of working under the GHz condition.

There are many kinds of existing soft magnetic materials, such as pure iron, silicon steel sheet, iron nickel, ferrite (manganese zinc, nickel zinc, etc.), iron powder core (Fe), alloy magnetic powder core (Fe-Si, Fe-Si-Al, Fe-Si-Cr, Fe-Ni, etc.), amorphous nanocrystalline material, etc. Although metal or alloy soft magnetic materials such as pure iron, silicon steel sheets, iron nickel and the like have high saturation magnetization and low coercivity so as to cause low hysteresis loss, the materials have low resistivity and high eddy current loss at high frequency, and generally can only work at frequencies of tens of Hz to hundreds of Hz. If metal Magnetic powder (Fe powder, etc.) or alloy powder (Fe-Si, Fe-Si-Al, Fe-Si-Cr, Fe-Ni, etc.) is coated with insulating agent, then pressed and formed, it can be made into SMC (Soft Magnetic composites) device with larger resistivity, so as to work under kHz frequency, but the frequency band still has a long distance from GHz. Ferrite (manganese zinc, nickel zinc and the like) materials are oxides, have high resistivity and low eddy current loss in a high-frequency working state, so that the ferrite materials can work under the frequency of MHz, but the materials are low in saturation magnetization, so that the miniaturization development of devices is not facilitated, and the working frequency band of the materials still cannot meet the development requirements of electronic devices. In addition, amorphous/nanocrystalline materials are also soft magnetic materials which have attracted much attention in recent years, and the materials not only have high saturation magnetization, but also can work at about 100kHz, so the materials are gradually applied to the fields of power grid transformers, wireless charging and the like, but the working frequency of the materials cannot reach 1 MHz.

In order to develop a soft magnetic material capable of working under GHz, intensive research is carried out by some colleges and universities or scientific research institutes in China, the cut-off frequency of rare earth-iron-nitrogen compounds (such as Ce-Fe-N, Nd-Fe-N and the like) is found to be very high and can reach 6-10GHz, and then the idea of applying the rare earth-iron-nitrogen compounds to high-frequency devices is proposed. However, the material still has large hysteresis loss, eddy current loss and dielectric loss under the GHz condition, so that the material can be applied to the wave-absorbing field by utilizing the high-frequency loss characteristic to filter out the GHz clutter, and has limitations in other fields such as inductance, radio frequency and the like.

For example, CN110047637A proposes a method for preparing a rare earth-iron-nitrogen composite magnetic material, which prepares an Nd-Fe-N composite rare earth material and tests the electromagnetic absorption and shielding properties of the material. However, the disclosed Nd-Fe-N composite rare earth material still has defects in material components, preparation process and performance, and particularly, nano-scale powder particles are not manufactured.

CN109982791A discloses a rare earth iron-nitrogen-based magnetic powder excellent in heat resistance and magnetic properties, particularly in coercive force and magnetization, and a method for producing the same. The rare earth iron-nitrogen magnetic powder of this embodiment contains rare earth elements R, iron Fe, and nitrogen N as main components and has Th₂Zn₁₇Type Th₂Ni₁₇Type TbCu₇In the magnetic powder of any one of the above forms, the average particle diameter is 1 to 10 μm, and a shell layer having the same crystal structure is formed on the particle surface of the powder, wherein 1 to 20 at% of Fe is substituted by Cr, 10 to 20 at% of N is 10 to 20 at%, the thickness is 10 to less than 200nm, and the thickness is less than 2% of the average particle diameter of the powder. However, the above materials have good permanent magnetic properties and insufficient soft magnetic properties due to differences in alloy components and microstructures.

Peter Koll a.r et al disclose the preparation of Ce₂Fe₁₇N_3-δMethod of compounding and testing the high frequency (GHz) absorption characteristics of the materials: (Kollár,Peter,et al."Steinmetz law for ac magnetizediron phenolformaldehyde resin soft magnetic composites."Journal of Magnetism&Magnetic Materials 424(2017): 245-. However, the high frequency eddy current loss and the dielectric loss of the material prepared by the method are still high.

In view of the above, there is a need to develop a high-frequency low-loss composite soft magnetic material, a preparation method thereof, and applications thereof, so as to satisfy the use of various high-frequency electronic devices, especially electronic devices operating under GHz conditions.

Disclosure of Invention

In order to solve the technical problems, the invention provides a high-frequency low-loss composite soft magnetic material, a preparation method and application thereof₂M_xT_yThe metal magnetic powder has a particle size D50 of 100-300nm and a shape of nearly spherical. The invention optimizes the composition and microstructure of the metal magnetic powder in the composite soft magnetic material, and compounds the metal magnetic powder with an insulating binder to obtain the high-frequency low-loss composite soft magnetic material, which can greatly reduce the eddy current loss and make the composite soft magnetic material more suitable for working under the GHz condition, wherein the cut-off frequency is 8.5-10.2GHz, the magnetic permeability mu' is 1.2-2.2 under the frequency of 6GHz, and the magnetic loss tan delta mu is 0.05-0.15.

In order to achieve the purpose, the invention adopts the following technical scheme:

it is an object of the present invention to provide a high-frequency low-loss composite soft magnetic material including a metal magnetic powder including R and a binder₂M_xT_y(ii) a Wherein R comprises Ce, M comprises Fe, T comprises N, x and y are the atomic contents of M and T respectively, x ranges from 16 to 26, y ranges from 2.5 to 3, the particle size D50 of the metal magnetic powder is 100-300nm and the shape of the metal magnetic powder is nearly spherical.

According to the relevant magnetic theory, the magnetic loss of soft magnetic materials is mainly caused by the hysteresis loss W_hEddy current loss W_clAnd residual loss W_excThe three parts are as follows. Wherein, under the low-frequency working condition, the loss of the material is mainly hysteresis loss,whereas the eddy current losses increase sharply with increasing operating frequency. Generally, the most critical influencing factors of the eddy current loss of soft magnetic materials are the electrical conductivity σ, the particle size d and the operating frequency f. Wherein the eddy current loss of the soft magnetic material under high frequency operating conditions is proportional to the square of the grain size d of the material. Therefore, in order to reduce the high frequency eddy current loss of the soft magnetic material, it is critical to reduce the electrical conductivity of the material and to reduce the grain size of the material.

Although the main components of the metal magnetic powder in the composite soft magnetic material are still metal elements with good electrical conductivity, namely the rare earth element R and the ferromagnetic element M, through optimizing the component composition and the microstructure of the metal magnetic powder in the composite soft magnetic material, on one hand, the rare earth element R and the ferromagnetic element M form the component proportion of the composite soft magnetic material, and are combined with the non-metal element containing N, the cut-off frequency can be improved, the electrical conductivity can be reduced, and the high-frequency eddy current loss of the metal magnetic powder can be reduced; on the other hand, the metal magnetic powder is limited to the nano-particles with the particle size D50 of 100-300nm and the shape of nearly spherical, and the particle size D is nano-scale, so that the eddy current loss is greatly reduced, the magnetic domain moving distance under the high-frequency condition is also reduced, the residual loss of the material is reduced, and the total high-frequency loss of the metal magnetic powder is greatly reduced. In addition, the metal magnetic powder is compounded with the insulating binder, so that the electric conductivity is further reduced, and the high-frequency eddy current loss of the composite material is further reduced. Therefore, the composite soft magnetic material has the performance of high frequency and low loss, is more suitable for working under the GHz condition, has the cutoff frequency of 8.5-10.2GHz, and has the magnetic permeability mu' of 1.2-2.2 and the magnetic loss tan delta mu of 0.05-0.15 under the frequency of 6 GHz.

The metal magnetic powder of the invention comprises R₂M_xT_yX and y are the atomic contents of M and T, respectively, and x is in the range of 16 to 26, such as 16, 17, 20, 23, 25 or 26, but not limited to the recited values, and other unrecited values within the range of values are equally applicable.

The metal magnetic powder of the invention comprises R₂M_xT_yX and y are atoms of M and T, respectivelyThe content, y, is in the range of 2.5 to 3, such as 2.5, 2.55, 2.57, 2.58, 2.75, 2.82, 2.85 or 3, etc., but is not limited to the recited values, and other values not recited in the numerical range are also applicable.

The particle size D50 of the metal magnetic powder of the present invention is 100-300nm, such as 100nm, 120nm, 150nm, 180nm, 200nm, 220nm, 250nm, 280nm or 300nm, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

In the metal magnetic powder, R further includes any one or a combination of at least two of Sm, Nd, Pr, and Ho, but is not limited to the above elements, and other rare earth elements that can perform the same function may also be used in the present invention.

Preferably, in the metal magnetic powder, M further includes Co and/or Ni, but is not limited to the above elements, and other ferromagnetic elements that can perform the same function may also be used in the present invention.

Preferably, in the metal magnetic powder, T further includes H and/or O.

Preferably, the metal magnetic powder is surface-modified.

Preferably, the surface modification comprises forming a passivation layer on the surface and/or coating a coupling agent on the surface.

Preferably, the coupling agent comprises any one of a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent, or a combination of at least two thereof.

In a preferred embodiment of the present invention, the binder includes one or a combination of at least two of paraffin, epoxy resin, nylon, and polyvinyl alcohol, and the binder has a low dielectric constant, so that the high-frequency dielectric loss of the composite soft magnetic material can be reduced.

Preferably, in the high-frequency low-loss composite soft magnetic material, the mass of the binder is 5 to 40% of the mass of the metal magnetic powder, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or the like, but is not limited to the enumerated values, and other values not enumerated within the range of the enumerated values are also applicable.

Preferably, the binder is coated on the surface of the metal magnetic powder.

Preferably, the high-frequency low-loss composite soft magnetic material is granular.

The second purpose of the present invention is to provide a method for preparing the high-frequency low-loss composite soft magnetic material, which comprises the following steps:

(1) preparing metal magnetic powder comprising R₂M_xT_y(ii) a Wherein R comprises Ce, M comprises Fe, T comprises N, x and y are the atomic contents of M and T respectively, the range of x is 16-26, and the range of y is 2.5-3;

(2) and (2) mixing the metal magnetic powder obtained in the step (1) with a binder according to a formula amount, and processing to obtain the high-frequency low-loss composite soft magnetic material.

As a preferable technical scheme of the invention, the preparation method of the metal magnetic powder in the step (1) comprises the following steps:

(i) according to R₂M_xWeighing the acetylacetone compound of R and the acetylacetone compound of M, adding the weighed acetylacetone compounds into an organic solvent, uniformly mixing, and then adding calcium acetylacetonate for full stirring;

(ii) (ii) subjecting the liquid mixture obtained in step (i) to a thermal decomposition treatment to obtain a solid mixture;

(iii) and (iii) sequentially carrying out reduction treatment, nitridation treatment and cleaning treatment on the solid mixture obtained in the step (ii) to obtain the metal magnetic powder.

In connection with the process for producing the metal magnetic powder, the acetylacetonates of R and M in step (i) are such that the formation of R is provided₂M_xWhich, after decomposition in step (ii), form fine R particles having a nano-scale particle size₂O₃And M₂O₃. The calcium acetylacetonate acts to adjust R₂M_x(iii) a particle size controlling agent which forms fine CaO dispersed in R after decomposition in step (ii)₂O₃And M₂O₃The content of the powder particles can be adjustedTo adjust the particle size of the metal magnetic powder formed in step (iii).

Compared with the method for preparing metal magnetic powder by reducing metal oxide in the prior art, the metal magnetic powder is prepared by thermally decomposing an organic mixture, has the characteristics of fine particles and high activity, is easy to obtain metal compounds with fine crystal grains by reduction at a lower temperature, has high diffusion speed among atoms, and is difficult to generate impurity phases, so that the high-performance nanocrystalline magnetic powder is obtained.

As a preferred technical scheme of the invention, the organic solvent in the step (i) is oleylamine.

Preferably, the amount by mass of calcium acetylacetonate in step (i) is 10-80% of the sum of the amounts by mass of R and M, for example 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80%, but is not limited to the recited values, and other values not recited in this range are equally applicable.

Preferably, the temperature of the thermal decomposition treatment in step (ii) is 150-.

Preferably, the time for the thermal decomposition treatment in step (ii) is 4 to 6 hours, such as 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours, but not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the reducing agent used in the reduction treatment in step (iii) is metallic calcium.

Preferably, the reduction treatment in step (iii) is performed under the protection of argon.

Preferably, the temperature of the reduction treatment in step (iii) is 850-.

Preferably, the holding time of the reduction treatment in step (iii) is 30-60min, such as 30min, 35min, 40min, 45min, 50min, 55min or 60min, but not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the nitriding treatment of step (iii) is performed in an ammonia atmosphere.

Preferably, the temperature of the nitriding treatment in step (iii) is 400-.

Preferably, the incubation time for the nitriding treatment in step (iii) is 3-5h, such as 3h, 3.5h, 4h, 4.5h or 5h, but not limited to the recited values, and other values not recited in the range of values are also applicable.

Preferably, the washing treatment of step (iii) comprises a deionized water washing and an ethanol filtering washing which are sequentially carried out.

The cleaning is carried out at room temperature, the calcium-containing impurities in the solid mixture after the nitriding treatment, including calcium oxide which is a reaction product of calcium acetylacetonate and metal calcium, are removed by deionized water cleaning, then the water in the solid mixture is reduced by ethanol filtering and cleaning, and finally the mixture of the metal magnetic powder and ethanol is obtained, and the ethanol can be removed by volatilization in the subsequent operation.

As a preferable technical scheme of the present invention, before the step (2) of mixing the metal magnetic powder with the binder, the method further comprises performing surface passivation and surface coating on the metal magnetic powder in sequence to obtain the surface-modified metal magnetic powder.

Preferably, the passivating agent used for the surface passivation treatment is a phosphoric acid solution.

Preferably, the mass of the phosphoric acid in the phosphoric acid solution is 0.5-1% of the mass of the metal magnetic powder, such as 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, but not limited to the enumerated values, and other unrecited values within the range of the enumerated values are also applicable.

Preferably, the coupling agent used in the surface coating treatment comprises any one of a silane coupling agent, a titanate coupling agent or an aluminate coupling agent or a combination of at least two of the silane coupling agent, the titanate coupling agent or the aluminate coupling agent.

Preferably, the mass of the coupling agent is 0.5 to 1% of the mass of the metal magnetic powder, such as 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, but not limited to the recited values, and other values not recited within the range of values are also applicable.

In a preferred embodiment of the present invention, the mass of the binder in step (2) is 5 to 40% of the mass of the metal magnetic powder, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%, but is not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.

Preferably, the processing treatment in step (2) includes: and putting the mixture of the metal magnetic powder and the binder into a double-screw granulator, mixing under the protection of nitrogen to obtain a rubber-magnetic mixture, and then cutting the rubber-magnetic mixture into particles by using a granulator.

As a preferred technical scheme of the invention, the preparation method comprises the following steps:

(1) preparing metal magnetic powder comprising R₂M_xT_y(ii) a Wherein R comprises Ce, M comprises Fe, T comprises N, x and y are the atomic contents of M and T respectively, the range of x is 16-26, and the range of y is 2.5-3;

(i) according to R₂M_xWeighing the acetylacetone compound of R and the acetylacetone compound of M, adding into oleylamine, mixing uniformly, and adding calcium acetylacetonate for full stirring; the mass of the calcium acetylacetonate is 10-80% of the sum of the mass of the acetylacetonate of R and the acetylacetonate of M;

(ii) (ii) subjecting the liquid mixture obtained in the step (i) to heating decomposition treatment at the temperature of 150 ℃ and 250 ℃ for 4-6h to obtain a solid mixture;

(iii) adding metal calcium into the solid mixture obtained in the step (ii), heating to 850-plus 900 ℃ under the protection of argon, preserving heat for 30-60min for reduction treatment, then cooling to 400-plus 500 ℃, extracting argon, filling ammonia gas, preserving heat for 3-5h, performing nitridation treatment under the atmosphere of ammonia gas, then cooling to room temperature, firstly performing reverse deionized water cleaning, and then performing ethanol filtering and washing to obtain the metal magnetic powder;

(2) adding the metal magnetic powder in the step (1) into a phosphoric acid solution, repeatedly stirring the phosphoric acid solution under the protection of nitrogen to perform surface passivation treatment, then adding a coupling agent to perform surface coating treatment, wherein the mass of the coupling agent is 0.5-1% of that of the metal magnetic powder, then mixing the coupling agent with a binder, the mass of the binder is 5-40% of that of the metal magnetic powder, putting the mixture of the metal magnetic powder and the binder into a double-screw granulator, mixing the mixture under the protection of nitrogen to obtain a rubber-magnetic mixture, and then cutting the rubber-magnetic mixture into particles by using a granulator to obtain the high-frequency low-loss composite soft magnetic material.

The invention also aims to provide application of the high-frequency low-loss composite soft magnetic material, which is used for preparing wave-absorbing, inductance and radio-frequency devices.

The high-frequency low-loss composite soft magnetic material can be made into a magnet device by adopting a mould pressing, injection or calendering method, and the magnet device is preferably made by adopting an injection process from the angle of reducing loss and obtaining higher magnetic conductivity.

Compared with the prior art, the invention has at least the following beneficial effects:

the invention optimizes the composition and microstructure of the metal magnetic powder in the composite soft magnetic material, and compounds the metal magnetic powder with an insulating binder to obtain the high-frequency low-loss composite soft magnetic material, which can greatly reduce the eddy current loss and make the composite soft magnetic material more suitable for working under the GHz condition, wherein the cut-off frequency is 8.5-10.2GHz, the magnetic permeability mu' is 1.2-2.2 under the frequency of 6GHz, and the magnetic loss tan delta mu is 0.05-0.15.

Detailed Description

For the purpose of facilitating an understanding of the present invention, the present invention will now be described by way of examples. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

In the present invention, all the equipment, materials and the like are commercially available or commonly used in the industry, if not specified. The methods in the following examples are conventional in the art unless otherwise specified.

Example 1

The embodiment provides a high-frequency low-loss composite soft magnetic material and a preparation method thereof, wherein the high-frequency low-loss composite soft magnetic material comprises metal magnetic powder and a binder, and the metal magnetic powder comprises R₂M_xT_y(ii) a Wherein R is Ce, M is Fe, T is a combination of N, H and O, x and y are atomic contents of M and T respectively, x is 16, namely the atomic ratio of Ce to Fe is 1:8, y is 2.85, based on the total mass of T as 100%, the content of N is 95%, the content of H is 3.2%, the content of O is 1.8%, the particle diameter D50 of the metal magnetic powder is 210nm and is approximately spherical;

the preparation method comprises the following steps:

(1) the metal magnetic powder is prepared according to the following steps:

(i) according to R₂M_xThe component ratio of (A) is 1:8, R is Ce, M is Fe, and cerium acetylacetonate (C) is weighed₁₅H₂₁CeO₆) And iron (C) acetylacetonate₁₅H₂₁FeO₆) Adding into oleylamine, mixing, and adding calcium acetylacetonate (C)_1OH₁₄CaO₄) Fully stirring; wherein, C_1OH₁₄CaO₄Has a mass of C₁₅H₂₁CeO₆And C₁₅H₂₁FeO₆10% of the sum of the masses;

(ii) (ii) subjecting the liquid mixture obtained in step (i) to a thermal decomposition treatment at 200 ℃ for 5h to obtain a solid mixture;

(iii) adding metal calcium into the solid mixture obtained in the step (ii), heating to 850 ℃ under the protection of argon, preserving heat for 30min for reduction treatment, then cooling to 400 ℃, extracting argon, filling ammonia gas, preserving heat for 4h, performing nitridation treatment under the atmosphere of ammonia gas, then cooling to room temperature, firstly performing repeated deionized water cleaning, and then performing ethanol filtering and washing to obtain the metal magnetic powder;

(2) adding the metal magnetic powder in the step (1) into a phosphoric acid solution, repeatedly stirring the phosphoric acid solution to perform surface passivation treatment under the protection of nitrogen, then adding a silane coupling agent to perform surface coating treatment, wherein the mass of the silane coupling agent is 1% of that of the metal magnetic powder, then mixing the silane coupling agent with nylon, the mass of the nylon is 40% of that of the metal magnetic powder, placing the mixture of the metal magnetic powder and a binder into a double-screw granulator, mixing the mixture under the protection of nitrogen to obtain a rubber-magnetic mixture, and then cutting the rubber-magnetic mixture into particles by using a granulator to obtain the high-frequency low-loss composite soft magnetic material.

Example 2

This example provides a high frequency low loss composite soft magnetic material and a method for preparing the same, except that "R" in step (1) of the preparation method₂M_xThe component ratio of (A) is 1:8 (the atomic ratio of Ce to Fe is 1:8), namely x is 16' and is replaced by R₂M_xThe high-frequency low-loss composite soft magnetic material was prepared in the same manner as in example 1 except that the component ratio of (1: 8.5) was 1:8.5 (the atomic ratio of Ce to Fe was 1:8.5), that is, x was 17 ", and y was 2.75, and the metal magnetic powder had a particle diameter D50 of 220nm and a nearly spherical shape, and contained 95.5% of N, 2.8% of H and 1.7% of O, based on 100% of the total mass T.

Example 3

This example provides a high frequency low loss composite soft magnetic material and a method for preparing the same, except that "R" in step (1) of the preparation method₂M_xThe component ratio of (A) is 1:8 (the atomic ratio of Ce to Fe is 1:8), namely x is 16' and is replaced by R₂M_xThe high-frequency low-loss composite soft magnetic material was prepared in the same manner as in example 1 except that the component ratio of (1: 13) was 1:13 (the atomic ratio of Ce to Fe was 1:13), that is, x was 26 ″, and y was 2.57, the content of N was 95.3%, the content of H was 3.5%, and the content of O was 1.2%, based on 100% of the total mass of T, and the metal magnetic powder had a particle diameter D50 of 230nm and a nearly spherical shape.

Example 4

The embodiment provides a high-frequency low-loss deviceA consumable composite soft magnetic material and a method for producing the same, except that "C" in step (1) of the production method_1OH₁₄CaO₄Has a mass of C₁₅H₂₁CeO₆And C₁₅H₂₁FeO₆10% of the sum of masses "replaced by" C_1OH₁₄CaO₄Has a mass of C₁₅H₂₁CeO₆And C₁₅H₂₁FeO₆80% of the total mass "the other conditions were exactly the same as in example 1, and the obtained high-frequency low-loss composite soft magnetic material was prepared such that y was 2.82, the N content was 94.5%, the H content was 3.5%, and the O content was 2.0% with respect to 100% of the total mass T, and the metal magnetic powder had a particle diameter D50 of 130nm and a nearly spherical shape.

Example 5

This example provides a high-frequency low-loss composite soft magnetic material and a preparation method thereof, except that the temperature of the reduction treatment in step (iii) of the preparation method is changed from "850 ℃ to" 900 ℃, and other conditions are exactly the same as those in example 1, and the prepared high-frequency low-loss composite soft magnetic material has y of 2.55, the N content of 95.3%, the H content of 2.7%, the O content of 2.0%, and the metal magnetic powder has a particle size D50 of 270nm and a nearly spherical shape, wherein T is 100% by total mass.

Example 6

This example provides a high-frequency low-loss composite soft magnetic material and a preparation method thereof, except that the time of reduction treatment in step (iii) of the preparation method is changed from "30 min" to "60 min", and the conditions are exactly the same as those in example 1, and the prepared high-frequency low-loss composite soft magnetic material has y of 2.58, the total T mass is 100%, the N content is 95.1%, the H content is 2.8%, the O content is 2.1%, and the metal magnetic powder has a particle size D50 of 250nm and a shape of an approximately spherical shape.

Example 7

This example provides a high-frequency low-loss composite soft magnetic material and a preparation method thereof, except that the temperature of the nitriding treatment in step (iii) of the preparation method is replaced by "500 ℃, and the other conditions are exactly the same as those in example 1, and the prepared high-frequency low-loss composite soft magnetic material has y of 3.0, wherein the total T mass is 100%, the N content is 98.2%, the H content is 1.1%, the O content is 0.7%, and the metal magnetic powder has a particle size D50 of 240nm and a nearly spherical shape.

Example 8

This example provides a high-frequency low-loss composite soft magnetic material and a preparation method thereof, except that in step (1) of the preparation method, "R" is Ce, and the source is cerium acetylacetonate (C)₁₅H₂₁CeO₆) "substituted" with a combination of Ce and Sm with R in a 9:1 molar ratio, the source being cerium (C) acetylacetonate₁₅H₂₁CeO₆) With samarium (C) acetylacetonate₁₅H₂₁SmO₆) The high-frequency low-loss composite soft magnetic material obtained was prepared under the same conditions as in example 1 except that y was 2.85, the total T mass was 100%, the N content was 95%, the H content was 3.3%, and the O content was 1.7%, and the metal magnetic powder had a particle diameter D50 of 215nm and a nearly spherical shape.

Example 9

This example provides a high-frequency low-loss composite soft magnetic material and a preparation method thereof, except that in step (1) of the preparation method, "M" is Fe, and the source is iron acetylacetonate (C)₁₅H₂₁FeO₆) "substituted" by M a combination of Fe and Co in a 9:1 molar ratio, the source being iron acetylacetonate (C)₁₅H₂₁FeO₆) With cobalt (C) acetylacetonate₁₅H₂₁CoO₆) The high-frequency low-loss composite soft magnetic material obtained was prepared under the same conditions as in example 1 except that y was 2.82, the total T mass was 100%, the N content was 95.8%, the H content was 3.1%, and the O content was 1.1%, and the metal magnetic powder had a particle diameter D50 of 220nm and a nearly spherical shape.

Comparative example 1

This comparative example provides a composite soft magnetic material, except that "the metal magnetic powder has a particle diameter D50 of 210nm and a nearly spherical shape" was replaced with "the metal magnetic powder has a particle diameter D50 of 500nm and a nearly spherical shape", and the other conditions were exactly the same as in example 1.

Performance testing

(1) And (3) magnetic property testing: performing injection molding on the composite soft magnetic material described in the above examples and comparative examples to prepare a ring sample with an outer diameter of 20mm, an inner diameter of 10mm and a height of 5mm, and performing magnetic property test with a vector network analyzer at a frequency of 6GHz to obtain corresponding magnetic permeability mu' and magnetic loss tan delta mu;

(2) and (3) testing the cut-off frequency: and (3) carrying out magnetic performance test on the circular ring sample by using a vector network analyzer at a frequency band of 1-30GHz to obtain the cut-off frequency of the material.

The results of the above tests are summarized in table 1.

TABLE 1

As can be seen from table 1:

(1) the invention optimizes the composition and microstructure of the metal magnetic powder in the composite soft magnetic material, and compounds the metal magnetic powder with an insulating binder to obtain the high-frequency low-loss composite soft magnetic material, which can greatly reduce the eddy current loss and make the composite soft magnetic material more suitable for working under the GHz condition, wherein the cut-off frequency is 8.5-10.2GHz, the magnetic permeability mu' is 1.2-2.2 under the frequency of 6GHz, and the magnetic loss tan delta mu is 0.05-0.15;

(2) comparing example 1 with comparative example 1, since the particle diameter D50 of the metal magnetic powder of comparative example 1 is 500nm, which is out of the range of "100-300 nm" limited by the present invention, the eddy current loss of the composite soft magnetic material is increased, the magnetic loss tan δ μ is as high as 0.32, and the magnetic permeability μ' is slightly increased, and the cutoff frequency is slightly lowered, resulting in a decrease in the overall performance of the composite soft magnetic material.

The applicant states that the present invention is illustrated by the above examples to show the detailed process equipment and process flow of the present invention, but the present invention is not limited to the above detailed process equipment and process flow, i.e. it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.