CN115798855A - A soft magnetic composite material coated with amorphous and silicon oxide and its preparation method - Google Patents

Abstract

The invention discloses a preparation method of a soft magnetic composite material compositely coated by amorphous silicon oxide, belonging to the technical field of magnetic materials. The method comprises the steps of firstly preparing amorphous alloy powder with a fine median grain size through coarse grinding and fine grinding; then the magnetic powder is compounded and insulated by combining with the nano silicon oxide; then, a special annealing heat treatment process is set based on the crystallization temperature of the amorphous alloy, and the soft magnetic composite material clad by the amorphous alloy powder and the silicon oxide is prepared. The relative magnetic permeability of the soft magnetic composite material at 100kHz/1V is 60.7-63.2, and the volume resistivity is 6.942-8.565 multiplied by 10 ¹⁰ Mu omega cm, the loss of 50kHz/100mT is 188-582 mW/cm ³ The DC bias performance under the magnetic field strength of 100Oe is 61.4-90.2%. The preparation method can obtain the soft magnetic composite material with optimized magnetic conductivity, resistivity, loss and direct current bias performance.

Description

A soft magnetic composite material coated with amorphous and silicon oxide and its preparation method

technical field

The invention belongs to the technical field of magnetic materials, and relates to a preparation method of a soft magnetic composite material coated with amorphous and silicon oxide.

Background technique

With the rapid development of the new energy industry, soft magnetic composite materials, as the core components of power electronic equipment such as photovoltaic inverters, vehicle chargers, and inverter air conditioners, have received more and more attention. Especially for high-frequency and high-power applications, soft magnetic composite materials are required to have higher resistivity, magnetic permeability, DC bias performance and lower loss. To achieve this goal, it is the key to evenly coat a dense high-resistivity insulating layer on the surface of the magnetic powder, and the insulating layer should preferably have certain magnetic properties. At present, the high-resistivity insulating materials used in soft magnetic composite materials are mainly inorganic oxides. Considering the process operability of uniform coating and the basic physical properties of high resistivity, silicon oxide is currently recognized as the best insulating oxide. . However, the simple silicon oxide coating cannot realize the synchronous improvement of resistivity and magnetic permeability. This is because silicon oxide is a non-magnetic substance. Although its coating layer can effectively increase the resistivity of the soft magnetic composite material, it will also block the magnetic path between the magnetic powder particles, resulting in an increase in the demagnetization field and static magnetization of the internal structure of the soft magnetic composite material. The reduction of the coupling field leads to the decrease of the magnetic permeability of the soft magnetic composite material, the increase of the magnetic core loss, and the enhancement of the DC bias performance.

Contents of the invention

The object of the present invention is to provide a method for preparing a soft magnetic composite material coated with amorphous and silicon oxide.

The present invention first produces amorphous magnetic powder with a median particle size of 4-6 μm by two-step ball milling of coarse grinding and fine grinding. The iron-based alloy magnetic powder is then compounded and insulated, and finally the insulating magnetic powder is pressed into a soft magnetic composite material coated with amorphous alloy powder and silicon oxide to achieve resistivity, permeability, loss and DC bias. Synchronization optimization for configuration performance. The key to the preparation method of the present invention is to design the ball milling and heat treatment process routes in a targeted manner, and prevent the crystallization of the amorphous alloy powder during the preparation process while controlling the particle size of the amorphous magnetic powder.

A method for preparing a soft magnetic composite material compositely coated with amorphous and silicon oxide, the specific operation steps are as follows:

(1) Preparation of amorphous alloy powder

Choose the amorphous alloy ribbon that the single-roll quick quenching method makes and place in the planetary ball mill and carry out ball milling twice respectively, described two ball mills are coarse grinding and fine grinding, and ball milling medium is ethanol; The obtained median particle diameter is 4 ~6μm amorphous alloy powder;

The amorphous alloy powder is one of iron silicon boron, iron silicon boron carbon, iron silicon boron phosphorus carbon;

(2) cleaning

Washing the amorphous alloy powder with acetone for 1 to 3 times to remove impurities on the surface of the amorphous alloy powder to obtain clean amorphous alloy powder;

(3) Insulation coating

Put the iron-based alloy magnetic powder with a particle size of 40-180 μm in an acetone solution, then mix the clean amorphous alloy powder and nano-silicon oxide powder evenly, pour it into the acetone solution and stir thoroughly, and dry it at 80°C to obtain insulating powder material;

The mass of the nano silicon oxide powder is 2% of the mass of the iron-based alloy magnetic powder, and the mass of the clean amorphous alloy powder is 2-6% of the mass of the iron-based alloy magnetic powder;

The mass ratio of the iron-based alloy magnetic powder to the acetone solution is 10:3;

(4) Preparation of green body

Mix the insulating powder and the release agent evenly, the amount of the release agent is 3‰～6‰ of the mass of the insulating powder, mix evenly, press and form in the mold to obtain a green body;

(5) heat treatment

Stress-relief annealing the green body in an argon atmosphere, and cooling to obtain a soft magnetic composite material clad with amorphous alloy powder and silicon oxide;

The relative magnetic permeability of the soft magnetic composite material under the condition of 100kHz/1V is 60.7-63.2, the volume resistivity is 6.942-8.565× ¹⁰¹⁰ μΩ·cm, and the loss under the condition of 50kHz/100mT is 188-582mW/ ^cm3 , The DC bias at 100Oe magnetic field strength is 61.4-90.2%.

Further technical scheme is as follows:

In step (1), the coarse grinding conditions: the grinding balls used are zirconia balls with a diameter of 10-20 cm, the rotational speed is 150-300 r/min, the ball milling time is 9-18 hours, and the ball-to-material ratio is 20:1; Describe the fine grinding conditions: the grinding balls used are zirconia balls with a diameter of 5-10 cm, the rotational speed is 300-500 r/min, the ball milling time is 9-32 hours, and the ball-to-material ratio is 30:1.

In step (3), the iron-based alloy magnetic powder is one of gas-atomized iron-silicon magnetic powder, gas-atomized iron-silicon-aluminum magnetic powder, and iron-nickel magnetic powder.

In step (4), the pressure of the compression molding is 1000-1200 MPa.

In step (5), the annealing conditions are: 100-200° C., heat preservation for 40-60 minutes; 350-420° C., 60-80 minutes heat preservation.

Beneficial technical effect of the present invention is embodied in the following aspects:

1. Amorphous alloy is a magnetic material with excellent soft magnetic properties. It has a significantly higher resistivity than magnetic powder particles of soft magnetic composite materials, and also has high magnetic permeability and low loss. Therefore, the present invention utilizes the characteristics of high resistivity, high magnetic permeability, and low loss of amorphous alloys, and mixes them with silicon oxide powder with high resistivity in a certain proportion to realize high-quality composite insulation of iron-based alloy magnetic powders. Therefore, the soft magnetic composite material is endowed with high resistivity, excellent magnetic permeability, low loss and high DC bias performance at the same time. The present invention prepares the amorphous alloy powder with a median particle size between 4 and 6 μm by subjecting the amorphous alloy strip to two-step mechanical ball milling of rough grinding and fine grinding. This two-step ball milling method can pass Adjust the ball-to-material ratio and the speed of the ball mill to crush the amorphous alloy powder into the required median particle size, so that it can be evenly filled in the gaps of the large-size iron-based alloy magnetic powder particles, which is more conducive to soft magnetic composite materials of forming. Figure 1 shows the X-ray diffraction (XRD) spectrum of the iron-nickel soft magnetic composite material prepared in Example 3 and the iron-nickel magnetic powder and amorphous alloy powder before insulation treatment. It can be seen from Figure 1 that the finished iron-nickel soft magnetic composite The XRD spectrum of the material obviously has a steamed bun peak signal compared with the iron-nickel magnetic powder before insulation treatment. This signal is consistent with the XRD spectrum signal of the amorphous alloy powder, which indicates that the amorphous alloy powder has entered the iron-nickel soft magnetic composite material through composite insulation.

2. In the present invention, by adjusting the mass ratio of nano silicon oxide powder and amorphous alloy powder, the uniformity of composite insulation coating is guaranteed to a certain extent, and the special ball milling and heat treatment process conditions set can effectively prevent non-crystalline Crystallization of crystal alloys, but it can well remove the internal stress caused by the pressing process.

3. Under the same magnetic permeability level (60±8%), the soft magnetic composite material prepared in Example 1 coated with amorphous alloy powder and silicon oxide and the aerosol prepared by the conventional insulation process Comparison of loss, volume resistivity and DC bias performance of iron-silicon-aluminum soft magnetic composite materials.

Table 1 Comparison of magnetoelectric properties of soft magnetic composite materials prepared by the process of Example 1 and the conventional insulation process

The comparative data are shown in Table 1, wherein No. 1 is a sample prepared by a conventional insulation process, and No. 2 is a soft magnetic composite material coated with amorphous alloy powder and silicon oxide compositely prepared by the process of the present invention. It can be seen that, at the same magnetic permeability level, the soft magnetic composite material coated with amorphous alloy powder and silicon oxide prepared by the present invention has higher magnetic permeability, higher resistivity, lower losses and higher DC bias performance.

Description of drawings

Fig. 1 is the X-ray diffraction (XRD) spectrum of the iron-nickel soft magnetic composite material prepared in Example 3 and the iron-nickel alloy magnetic powder and amorphous powder before insulation treatment.

Detailed ways

The content of the present invention will be described below in conjunction with specific embodiments.

Example 1

The preparation steps of a soft magnetic composite material coated with amorphous and silicon oxide are as follows:

(1) Preparation of amorphous alloy powder

FeSiB (Fe ₇₈ Si ₉ B ₁₃ ) amorphous alloy thin strips prepared by single-roll quick quenching were selected and placed in a planetary ball mill for two ball mills, which were coarse grinding and fine grinding. The diameter of the ball used for rough grinding is 10cm, the speed of ball milling is 150r/min, the time of ball milling is 9h, and the ratio of ball to material is 20:1; the diameter of ball used for fine grinding is 5cm, the speed of ball milling is 300r/min, the time of ball milling is 9h, The ball-to-material ratio is 30:1, and the ball milling medium is ethanol, and the iron-silicon-boron (Fe ₇₈ Si ₉ B ₁₃ ) amorphous alloy powder with a median particle size of 5.8 μm is obtained.

(2) cleaning

The iron-silicon-boron (Fe ₇₈ Si ₉ B ₁₃ ) amorphous alloy powder was washed once with acetone to remove impurities on the surface of the iron-silicon-boron (Fe ₇₈ Si ₉ B ₁₃ ) amorphous alloy powder to obtain a clean amorphous alloy powder.

(3) Insulation coating

Weigh 1000g of aerosolized FeSiAl magnetic powder with a particle size of 40-180μm and place it in 300g of acetone solution, then mix 20g of clean amorphous alloy powder with 20g of nano-silicon oxide powder, pour it into the acetone solution and stir thoroughly, Dry at ℃ to obtain insulating powder.

(4) Preparation of green body

Mix 1040g of insulating powder and 3.12g of release agent evenly, and press in a mold with a pressing pressure of 1000MPa to form a green body of a magnetic ring with a standard outer diameter of 1.06 inches.

(5) heat treatment

The green body of the magnetic ring is annealed under the protection of argon to remove stress, first at 100°C, and keep it for 40 minutes; then increase the heat treatment temperature to 350°C, keep it for 60 minutes, and cool it with the furnace to obtain FeSiB (Fe ₇₈ Si ₉ B ₁₃ ) Aerosolized iron-silicon-aluminum soft magnetic composite material coated with amorphous alloy powder and silicon oxide.

The gas-atomized FeSiAl soft magnetic composite material has a relative permeability of 63.2 at 100kHz/1V, a volume resistivity of 8.565× ¹⁰¹⁰ μΩ·cm, a loss of 188mW/ ^cm3 at 50kHz/100mT, and a magnetic field strength of 100Oe The dc bias performance under is 61.4%.

Example 2

The preparation operation steps of a soft magnetic composite material coated with amorphous alloy powder and silicon oxide are as follows:

(1) Preparation of amorphous alloy powder

The iron-silicon-boron-carbon (Fe ₈₂ Si ₄ B ₁₃ C) amorphous alloy ribbon obtained by single-roll quick quenching was selected and placed in a planetary ball mill for two ball mills, which were coarse grinding and fine grinding. The diameter of the balls used for coarse grinding is 15cm, the speed of ball milling is 200r/min, the time of ball milling is 15h, the ratio of ball to material is 20:1, the diameter of balls used for fine grinding is 8cm, the speed of ball milling is 400r/min, the time of ball milling is 20h, The ball-to-material ratio is 30:1, the ball milling medium is ethanol, and the iron-silicon-boron-carbon (Fe ₈₂ Si ₄ B ₁₃ C) amorphous alloy powder with a median particle size of 5.2 μm is obtained.

(2) cleaning

Wash the iron silicon boron carbon (Fe ₈₂ Si ₄ B ₁₃ C) amorphous alloy powder twice with acetone to remove impurities on the surface of the iron silicon boron carbon (Fe ₈₂ Si ₄ B ₁₃ C) amorphous alloy powder and obtain a clean amorphous alloy powder.

(3) Insulation coating

Weigh 1000g of gas-atomized iron-silicon magnetic powder with a particle size of 40-180μm and place it in 300g of acetone solution, then mix 40g of clean amorphous alloy powder with 20g of nano-silicon oxide powder, pour it into the acetone solution and stir thoroughly, Dry at ℃ to obtain insulating powder.

(4) Preparation of green body

Mix 1060g of insulating powder and 5.3g of release agent evenly, and press in a mold with a pressing pressure of 1100MPa to form a green body of a magnetic ring with a standard outer diameter of 1.06 inches.

(5) heat treatment

Under the protective atmosphere of argon, the green body of the magnetic ring is firstly kept at 150°C for 50 minutes; then the heat treatment temperature is increased to 390°C, kept at 70 minutes, and cooled with the furnace to obtain iron silicon boron carbon (Fe ₈₂ Si ₄ B ₁₃ C) Aerosolized iron-silicon soft magnetic composite material coated with amorphous alloy powder and silicon oxide.

The gas-atomized iron-silicon soft magnetic composite material has a relative permeability of 61.2 at 100kHz/1V, a volume resistivity of 7.632×10 ¹⁰ μΩ·cm, a loss of 582mW/cm ³ at 50kHz/100mT, and a magnetic field strength of 100Oe The DC bias performance is 77.3%.

Example 3

The preparation operation steps of a soft magnetic composite material coated with amorphous alloy powder and silicon oxide are as follows:

(1) Preparation of amorphous alloy powder

Fe-Si-B-P-C (Fe ₈₃ Si ₂ B ₁₁ P ₃ C) amorphous alloy strips prepared by single-roll quick quenching were selected and placed in a planetary ball mill for two ball mills. The two ball mills were coarse grinding and fine grinding. The diameter of the ball used for coarse grinding is 20cm, the speed of ball milling is 300r/min, the time of ball milling is 18h, and the ratio of ball to material is 20:1; The ball-to-material ratio is 30:1, and the ball milling medium is ethanol, and the iron-silicon-boron-phosphorus-carbon (Fe ₈₃ Si ₂ B ₁₁ P ₃ C) amorphous alloy powder with a median particle size of 4.8 μm is obtained;

(2) cleaning

Wash the iron silicon boron phosphorus carbon (Fe ₈₃ Si ₂ B ₁₁ P ₃ C) amorphous alloy powder with acetone three times to remove the iron silicon boron phosphorus carbon (Fe ₈₃ Si ₂ B ₁₁ P ₃ C) amorphous alloy powder surface impurities to obtain clean amorphous alloy powder;

(3) Insulation coating

Weigh 1,000g of iron-nickel magnetic powder with a particle size of 40-180μm and place it in 300g of acetone solution, then mix 60g of clean amorphous alloy powder with 20g of nano-silicon oxide powder, pour it into the acetone solution and stir thoroughly, and bake at 80°C Dry to obtain insulating powder.

(4) Preparation of green body

Mix 1080g of insulating powder and 5.40g of release agent evenly, and press in a mold with a pressing pressure of 1200MPa to form a green body of a magnetic ring with a standard outer diameter of 1.06 inches.

(5) heat treatment

Under the protective atmosphere of argon, the green body of the magnetic ring is firstly kept at 200°C for 60 minutes; then the heat treatment temperature is raised to 420°C, kept at 80 minutes, and cooled with the furnace to obtain Fe-Si-B-P-C (Fe ₈₃ Si ₂ B ₁₁ P ₃ C) Iron-nickel soft magnetic composite material coated with amorphous alloy powder and silicon oxide.

The iron-nickel soft magnetic composite material has a relative permeability of 60.7 at 100kHz/1V, a volume resistivity of 6.942×10 ¹⁰ μΩ·cm, a loss of 230mW/cm ³ at 50kHz/100mT, and a DC bias of 100Oe magnetic field strength. The setting performance is 90.2%.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be Included within the protection scope of the present invention.

Claims (5)

1. A method for preparing soft magnetic composite material compositely coated by amorphous and silicon oxide is characterized by comprising the following operation steps:

(1) Preparation of amorphous alloy powder

Placing an amorphous alloy thin strip prepared by a single-roller rapid quenching method in a planetary ball mill for ball milling twice respectively, wherein the ball milling twice is coarse grinding and fine grinding, and the ball milling medium is ethanol; preparing amorphous alloy powder with the median grain diameter of 4-6 mu m;

the amorphous alloy powder is one of iron silicon boron, iron silicon boron carbon and iron silicon boron phosphorus carbon;

(2) Cleaning of

Cleaning the amorphous alloy powder with acetone for 1-3 times, and removing impurities on the surface of the amorphous alloy powder to obtain clean amorphous alloy powder;

(3) Insulating coating

Putting iron-based alloy magnetic powder with the particle size of 40-180 mu m into an acetone solution, uniformly mixing clean amorphous alloy powder and nano silicon oxide powder, pouring the mixture into the acetone solution, fully stirring, and drying at 80 ℃ to obtain insulating powder;

the mass of the nano silicon oxide powder is 2% of that of the iron-based alloy magnetic powder, and the mass of the clean amorphous alloy powder is 2-6% of that of the iron-based alloy magnetic powder;

the mass ratio of the iron-based alloy magnetic powder to the acetone solution is 10;

(4) Preparation of the Green bodies

Uniformly mixing the insulating powder and a release agent, wherein the use amount of the release agent is 3-6 per mill of the mass of the insulating powder, uniformly mixing, and performing press forming in a mold to obtain a green body;

(5) Heat treatment of

Performing stress annealing on the green body under the protection of argon atmosphere, and cooling to obtain the soft magnetic composite material compositely coated by the amorphous alloy powder and the silicon oxide;

the relative magnetic permeability of the soft magnetic composite material under the condition of 100kHz/1V is 60.7-63.2, and the volume resistivity is 6.942-8.565 multiplied by 10 ¹⁰ Mu omega cm, the loss under the condition of 50kHz/100mT is 188-582 mW/cm ³ The DC bias at 100Oe magnetic field strength is 61.4-90.2%.

2. The method for preparing a soft magnetic composite material compositely coated with amorphous silicon and silicon oxide according to claim 1, wherein: in the step (1), the rough grinding conditions are as follows: the grinding ball is zirconia ball with the diameter of 10-20 cm, the rotating speed is 150-300 r/min, the ball milling time is 9-18 h, and the ball-material ratio is 20:1; the fine grinding conditions are as follows: the grinding ball is zirconia ball with the diameter of 5-10 cm, the rotating speed is 300-500 r/min, the ball milling time is 9-32 h, the ball-to-material ratio is 30:1.

3. the method for preparing a soft magnetic composite material compositely coated with amorphous silicon and silicon oxide according to claim 1, wherein: in the step (3), the iron-based alloy magnetic powder is one of gas-atomized iron-silicon magnetic powder, gas-atomized iron-silicon-aluminum magnetic powder and iron-nickel magnetic powder.

4. The method for preparing a soft magnetic composite material compositely coated with amorphous silicon and silicon oxide according to claim 1, wherein: in the step (4), the pressure intensity of the compression molding is 1000-1200 MPa.

5. The method for preparing a soft magnetic composite material compositely coated with amorphous silicon and silicon oxide according to claim 1, wherein: in the step (5), annealing conditions are as follows: keeping the temperature for 40-60 min at 100-200 ℃; keeping the temperature for 60-80 min at 350-420 ℃.

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