CN116646139A - High-strength low-loss soft magnetic alloy composite material and preparation method thereof - Google Patents

Abstract

The invention discloses a high-strength and low-loss composite material and a preparation method thereof. The soft magnetic alloy material is smelted to obtain an alloy liquid. After the alloy liquid is sprayed from a spray plate, it is cooled in a nitrogen atmosphere to obtain a soft magnetic alloy powder. The coupling agent modifies the surface of the soft magnetic alloy powder to obtain modified powder, mixes the modified powder with glass powder to obtain mixed powder, mixes the mixed powder with resin and then granulates to obtain pellets, and compresses the pellets to obtain magnetic rings. The magnetic ring is sintered to obtain the soft magnetic alloy composite material; in the present invention, the scientific composition design and reasonable matching process design of the alloy powder play an important role in reducing the power consumption of the material and improving the strength of the magnetic element. The prepared high-reliability, low-loss soft magnetic alloy material substantially solves the problem of the application of soft magnetic alloy materials in automotive electronics under high-frequency and high-current conditions.

Description

A kind of soft magnetic alloy composite material with high strength and low loss and preparation method thereof

technical field

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

Background technique

With the popularization of automotive electronics and the continuous improvement of customer demand for automotive functions, the power of DC-DC power supplies is increasing. This type of DC-DC power supply has the characteristics of high frequency, low voltage, and high current. Ordinary soft magnetic materials are suitable for high frequency, but because of their low Bs and easy saturation, it is difficult to meet the requirements of high current use. Soft magnetic alloy materials have high Bs, high magnetic permeability, excellent current superposition and high Curie temperature. Such characteristics are applied more and more in such high-power scenarios, but conventional soft magnetic alloy materials have low resistivity and large eddy current loss at high frequencies, resulting in severe heat generation and high loss, which limits the proportion of its use at high frequencies . Faced with the requirements of high frequency, low power consumption and high reliability of electronic devices, on the one hand, it is necessary to increase the resistivity of soft magnetic alloy materials to reduce the high frequency loss of materials. It is difficult to increase the resistivity of conventional coatings. , it is necessary to carry out innovative insulation coating on the surface of the alloy powder. On the other hand, in order to improve the strength of the components and improve the reliability of their use in automobiles, the current soft magnetic alloys generally adopt the process of impregnating resin after sintering. The strength of the magnet, but the process of impregnating the resin has little improvement in the strength of the magnet, and the aging problem of the resin leads to poor reliability. The existing low-loss material has poor bonding force between particles, and the strength is increased through resin impregnation, which has the risk of aging.

Contents of the invention

In order to solve the problems in the prior art, the first object of the present invention is to provide a method for preparing a soft magnetic alloy composite material with high strength and low loss. In the preparation method of the present invention, one is to ensure that the crystal grains inside the metal particles are small by rapid cooling to reduce the eddy current loss of the material; The sintering process further makes the glass evenly distributed among the particles, increases the resistivity between the particles so as to reduce the eddy current loss and improve the bonding force between the particles. By using this method, a soft magnetic alloy material with high strength and low loss can be prepared.

The second object of the present invention is to provide a high-strength and low-loss soft magnetic alloy composite material prepared by the above preparation method. The soft magnetic alloy composite material particles provided by the present invention have small internal grains and dense , Uniform glass micro-layers, which can meet the needs of current devices for high-frequency low-loss and high-strength high-reliability.

In order to achieve the above object, the present invention adopts the following technical solutions:

The invention discloses a method for preparing a high-strength and low-loss soft magnetic alloy composite material. The soft magnetic alloy material is smelted to obtain an alloy liquid. After the alloy liquid is sprayed from a spray plate, it is cooled in a nitrogen atmosphere to obtain a soft magnetic alloy powder. The coupling agent modifies the surface of the soft magnetic alloy powder to obtain a modified powder, mixes the modified powder with glass powder to obtain a mixed powder, mixes the mixed powder with a resin and granulates to obtain pellets, and compresses the pellets to obtain a magnetic ring. The magnetic ring is sintered to obtain a soft magnetic alloy composite material;

The composition of the soft magnetic alloy material in terms of mass percentage is as follows: Fe 90.75wt%-94.97wt%, Si 2.9wt%-4.5wt%, Al 2.0wt%-4.0wt%, B 0.1wt%-0.5wt% %, Mn 0.01wt%-0.05wt%, Ca 0.01wt%-0.15wt%, Ni 0.01wt%-0.05wt%.

The soft magnetic alloy material of the present invention can make the magnetic anisotropy constant and the hysteresis coefficient of the material close to zero by controlling Fe/Si/Al within the scope of the present invention, thereby reducing the magnetic loss, and at the same time through the addition of B, Mn and other elements Added to inhibit the growth of grain size and reduce the internal eddy current loss.

Further preferably, the composition of the soft magnetic alloy material is as follows in terms of mass percentage:

Fe90.75wt%～94.88wt%, Si2.9wt%～4.5wt%, Al2.0wt%～4.0wt%, B0.1wt%～0.5wt%, Mn0.01wt%～0.05wt%, Ca0.01wt%～ 0.15wt%, Ni0.01wt% ~ 0.05wt%.

In a preferred scheme, the melting temperature is 1300-1500°C.

In a preferred solution, the pressure of the nitrogen atmosphere is greater than or equal to 5 MPa. In the present invention, a larger nitrogen pressure is used to increase the cooling rate, and combined with the alloy composition of the present invention, the effect of refining grains can be achieved.

In a preferred solution, the particle size of the soft magnetic alloy powder is 3-25 μm. The inventors found that controlling the particle size of the soft magnetic alloy powder within the above range will result in optimal performance of the final soft magnetic alloy composite material. If the particle size is too small, the magnetic permeability will be low, and if the particle size is too large, the loss will be too high.

In the actual operation process, the obtained soft magnetic alloy powder is then added with a coupling agent for surface modification, wherein the solvents are preferably acetone and methyl ethyl ketone non-polar low-boiling solvents.

In a preferred scheme, the coupling agent is selected from silane coupling agents.

In the actual operation process, the soft magnetic alloy powder coupling agent is mixed with the soft magnetic alloy powder in a solvent, and the coupling agent is grafted on the surface of the soft magnetic alloy powder to obtain the modified powder.

In a preferred solution, the amount of the coupling agent added is 0.01% to 0.1% of the mass of the soft magnetic alloy powder.

In a preferred solution, the particle size of the glass powder is 0.1 μm˜0.5 μm.

In a preferred solution, the glass powder is selected from SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ -type glasses, preferably SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ -ZnO glass, and in the glass powder, The content of SiO ₂ is ≤ 65 wt%, and the content of B ₂ O ₃ is ≤ 15 wt%.

The inventors found that the use of SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ -type glass has good wettability and interface bonding with the soft magnetic alloy powder in the present invention. In the actual exploration process, the inventor tried a large number of glass powders , such as SiO ₂ -CaO-Na ₂ OP ₂ O ₅ -F glass, has insufficient surface wettability with the soft magnetic alloy powder of the present invention, poor interfacial bonding force, and poor strength improvement effect.

In a preferred solution, the resin is a mixed resin composed of PVB resin and silicone resin, and in the resin, PVB resin:silicone resin=1-3:7-9 in terms of mass ratio.

The inventors have found that controlling the performance of PVB resin and silicone resin within the above range will result in the best performance of the soft magnetic alloy composite material. If the PVB resin is used, the insulation of the soft magnetic alloy composite material will be deteriorated, and if it is too small, the molding will be affected. Effect.

In a preferred solution, the amount of the resin added is 1.0wt% to 3.0wt% of the mass of the mixed powder.

In a preferred solution, the compression molding pressure is 1500-2500 MPa.

In a preferred solution, the sintering process is: sintering at normal pressure in an air atmosphere first, and then pressurizing and sintering under a protective atmosphere; , and then keep it at 320°C-360°C for 1-4h. During the pressurized sintering, keep the pressure in the furnace at 20MPa-100MPa before 700°C, then raise the temperature to 700°C-750°C, keep it warm for 0.5h-1h, and control the heat preservation The pressure in the process is 10-30MPa.

In the sintering process of the present invention, normal pressure sintering is used first, so that the volatile matter can be separated from the magnet after the PVB and silicone resin are decomposed, and then pressure sintering is adopted under a protective atmosphere, because the glass begins to crystallize in the pressure sintering temperature section, which is accelerated by pressing. The exchange and infiltration between the glass part and the surface of the particles makes the particles and the glass layer tightly combined, thereby improving the strength of the magnet.

Further preferably, the protective atmosphere is a nitrogen atmosphere.

The inventors found that the present invention needs to be sintered in a protective atmosphere, and if sintered in air, the magnetic permeability will be too low.

The invention also provides a high-strength and low-loss soft magnetic alloy composite material prepared by the above preparation method.

Principles and advantages

The first method of the present invention is to reduce the internal eddy current of the soft magnetic alloy powder through the process of material composition optimization and matching; Among the magnetic alloy powders, the resistivity between the soft magnetic alloy particles is greatly improved, the high-frequency eddy current loss is reduced, and the bonding strength between the particles can be improved at the same time. The above scheme can not only reduce the loss, but also ensure the strength and anti-aging of the device and improve the reliability, which can fundamentally solve the application problem of the soft magnetic alloy in automotive electronics.

Generally speaking, the scientific composition design and reasonable matching process design of the alloy powder in the present invention play an important role in reducing the power consumption of the material and improving the strength of the magnetic element. The newly developed and prepared high-reliability, low-loss The soft magnetic alloy material substantially solves the problem of the application of the soft magnetic alloy material under the conditions of high frequency and high current in automotive electronics.

Description of drawings

Fig. 1: SEM picture of embodiment 1 powder, as can be seen from the figure, the particle surface is coated with a uniform glass powder.

Fig. 2: SEM picture of powder of comparative example 6, as can be seen from the figure, there is no coated powder on the particle surface.

Detailed ways:

The following will clearly and completely describe the technical solutions in the embodiments of the present invention, and the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

Example 1:

The alloy material will be selected, and its material composition is 90.75wt% Fe, 4.5wt% Si, 4.0wt% Al, 0.5wt% B, 0.05wt% Mn, 0.15wt% Ca, 0.05wt% Ni. The alloy material is melted in a smelting furnace at 1500°C, and then sprayed into alloy powder through the spray plate, and cooled in a nitrogen atmosphere, where the nitrogen pressure is 6MPa, and the alloy powder is cooled in nitrogen for 1.8 seconds. The particle size distribution of the prepared alloy material powder is in the range of 3 μm to 25 μm. After cleaning the surface of the alloy powder with a solvent, add 0.01wt% coupling agent to modify the surface of the material; the solvent is acetone, and the coupling agent is preferably triethoxysiloxane. Dry the powder after completion, add 1.0wt% glass powder and mix to form a mixed powder, wherein the glass powder particle size is 0.1 μm, wherein the glass powder composition is preferably SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ -ZnO glass, wherein the SiO ₂ content 70wt%, _{B2O3 content} 12wt%. Add the mixed powder to PVB and silicone resin to granulate to form granulated powder, and press under 1500MPa pressure to form a magnetic ring; put the magnetic ring into a nitrogen furnace and sinter in a nitrogen atmosphere to form the final product. Among them, in the mixed resin of PVB and silicone resin, the mass ratio of PVB:silicone resin is 1:9, and the mass ratio of the mixed resin to the mixed powder is 1.0wt%, wherein the air is preferably introduced before 320°C before sintering, Keep warm for 1 hour, keep warm at 320°C for 4 hours, then put the magnetic ring into the nitrogen furnace, keep the pressure in the furnace at 100MPa before 700°C, and keep the temperature at 700°C for 1 hour. The sintering pressure was kept at 30MPa.

Example 2:

The alloy material will be selected, and its material composition is 94.88wt% Fe, 2.9wt% Si, 2.0wt% Al, 0.1wt% B, 0.01wt% Mn, 0.01wt% Ca, 0.01wt% Ni. The alloy material is melted in a smelting furnace at 1300°C, and then sprayed into alloy powder through the spray plate, and cooled in a nitrogen atmosphere, where the nitrogen pressure is 8MPa, and the alloy powder is cooled in nitrogen for 1.5 seconds. The particle size distribution of the prepared alloy material powder is in the range of 3 μm to 25 μm. After cleaning the surface of the alloy powder through a solvent, add 0.1wt% coupling agent to modify the surface of the material; wherein the solvent is preferably butanone, and the coupling agent is preferably trimethoxysilane. Dry the powder after completion, add 0.1wt% glass powder and mix to form a mixed powder, wherein the glass powder particle size is preferably 0.5 μm, and the glass powder composition is preferably SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ -ZnO glass, wherein the SiO ₂ content 65wt%, B ₂ O ₃ content 10wt%. Add the mixed powder to PVB and silicone resin to granulate to form granulated powder, and press it under a pressure of 2500MPa to form a magnetic ring; put the magnetic ring into a nitrogen furnace and sinter in a nitrogen atmosphere to form the final product. Among them, in the mixed resin of PVB and silicone resin, the mass ratio of PVB:silicone resin is 3:7, and the mass ratio of the mixed resin to the mixed powder is 3.0wt%, wherein the air is preferably introduced before 360°C before sintering, at 150°C Keep warm for 1 hour, keep warm at 360°C for 1 hour, then put the magnetic ring into the nitrogen furnace, keep the pressure in the furnace at 20MPa before 700°C, the maximum sintering temperature is 750°C, keep the temperature at 0.5h, and keep the air pressure at 10MPa.

Embodiment 3:

The alloy material will be selected, and its material composition is 93.35wt% Fe, 3.5wt% Si, 2.8wt% Al, 0.2wt% B, 0.02wt% Mn, 0.10wt% Ca, 0.03wt% Ni. The alloy material is melted in a smelting furnace at 1400°C, and then sprayed into alloy powder through the spray plate, and cooled in a nitrogen atmosphere, where the nitrogen pressure is 6MPa, and the alloy powder is cooled in nitrogen for 1 second. The particle size distribution of the prepared alloy material powder is in the range of 3 μm to 25 μm. After cleaning the surface of the alloy powder with a solvent, add 0.05wt% to a coupling agent to modify the surface of the material; wherein the solvent is preferably acetone, and the coupling agent is preferably a silane coupling agent trimethoxysilane. After completion, dry the powder, add 0.05wt% glass powder and mix to form a mixed powder, wherein the glass powder particle size is preferably 0.2 μm, and the glass powder composition is preferably SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ -ZnO glass, wherein the SiO ₂ content 70wt%, B ₂ O ₃ content 9wt%. Add the mixed powder to PVB and silicone resin to granulate to form granulated powder, and press under 2000MPa pressure to form a magnetic ring; put the magnetic ring into a nitrogen furnace and sinter in a nitrogen atmosphere to form the final product. Among them, in the mixed resin of PVB and silicone resin, the mass ratio of PVB:silicone resin is 2:8, and the mass ratio of the mixed resin to the mixed powder is 2.0wt%, wherein the air is preferably passed in before 340°C before sintering, and at 130°C Keep warm for 1 hour, keep warm at 350°C for 2 hours, then put the magnetic ring into the nitrogen furnace, keep the pressure in the furnace at 50MPa before 700°C, the highest sintering temperature is 730°C, keep the temperature at 0.8H, and keep the air pressure at 20MPa.

Comparative example 1:

Other conditions are the same as in Example 1, except that the smelting temperature is 1250° C., and due to the viscosity of molten steel, the material with too large particle size cannot be obtained.

Comparative example 2:

Other conditions are the same as in Example 1, except that the nitrogen pressure is 3MPa.

Comparative example 3:

Other conditions are the same as in Example 1, except that the particle size distribution of the prepared alloy material powder is in the range of 26 μm to 75 μm.

Comparative example 4:

Other conditions are the same as in Example 1, except that the Al composition of the material is adjusted to 6.0wt%, and the specific composition is 88.75wt% Fe, 4.5wt% Si, 6.0wt% Al, 0.5wt% B, 0.05wt% Mn, 0.15wt% %Ca, 0.05wt% Ni.

Comparative example 5:

Other conditions are the same as in Example 1, except that elements such as Mn and Ca are removed from the material, and the specific composition is 91wt% Fe, 4.5wt% Si, 4.0wt% Al, 0.5wt% B.

Comparative example 6:

Other conditions are the same as in Example 1, except that the material is removed from the glass cladding layer.

Carry out performance evaluation to the magnetic ring that embodiment and comparative example sintering are finished, winding number of turns N=13Ts circle, use the magnetic permeability μ (1V/1MHz) of magnetic ring sample test of 3260B type LCR tester and use electronic universal testing machine SH-100 tests the collapse strength of the magnetic ring; uses the IWATSU-SY-8218 hysteresis loop instrument to test the power consumption of the magnetic ring, 50mT&1MHz), and the obtained performance data are shown in Table 1 and Table 2 respectively:

The performance data of the embodiment of table 1

The performance data of table 2 comparative example

Through the performance comparison of the examples and comparative examples in Table 1 and Table 2, it can be seen that the composition and process of the examples are within the scope of the patent, the power consumption of the obtained material is significantly lower than that of the comparative example, and the strength is significantly improved, which shows that the present invention Feasible and has great performance advantages.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, they can also make some simple deduction or replacement, which should be regarded as belonging to the patent of the present invention determined by the submitted claims. protected range.

Claims (10)

1. A preparation method of a high-strength low-loss soft magnetic alloy composite material is characterized by comprising the following steps: smelting a soft magnetic alloy material to obtain alloy liquid, spraying the alloy liquid by a spray disc, cooling in nitrogen atmosphere to obtain soft magnetic alloy powder, carrying out surface modification on the soft magnetic alloy powder by adopting a coupling agent to obtain modified powder, mixing the modified powder with glass powder to obtain mixed powder, mixing the mixed powder with resin, granulating to obtain granules, compacting the granules to obtain a magnetic ring, and sintering the magnetic ring to obtain the soft magnetic alloy composite material;

the soft magnetic alloy material comprises the following components in percentage by mass: 90.75 to 94.97 percent of Fe, 2.9 to 4.5 percent of Si, 2.0 to 4.0 percent of Al, 0.1 to 0.5 percent of B, 0.01 to 0.05 percent of Mn, 0.01 to 0.15 percent of Ca and 0.01 to 0.05 percent of Ni.

2. The method for preparing the high-strength low-loss soft magnetic alloy composite material according to claim 1, which is characterized in that: the smelting temperature is 1300-1500 ℃.

3. The method for preparing the high-strength low-loss soft magnetic alloy composite material according to claim 1, which is characterized in that: the air pressure of the nitrogen atmosphere is more than or equal to 5MPa.

4. The method for preparing the high-strength low-loss soft magnetic alloy composite material according to claim 1, which is characterized in that: the particle size of the soft magnetic alloy powder is 3-25 mu m.

5. The method for preparing the high-strength low-loss soft magnetic alloy composite material according to claim 1, which is characterized in that: the coupling agent is selected from silane coupling agents;

the addition amount of the coupling agent is 0.01-0.1% of the mass of the soft magnetic alloy powder.

6. The method for preparing the high-strength low-loss soft magnetic alloy composite material according to claim 1, which is characterized in that: the granularity of the glass powder is 0.1-0.5 mu m;

the glass powder is selected from SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ -a glass-like material of the glass powder, siO ₂ The content of (B) is less than or equal to 65 weight percent ₂ O ₃ The content is less than or equal to 15wt%.

7. The method for preparing the high-strength low-loss soft magnetic alloy composite material according to claim 1, which is characterized in that: the resin is mixed resin composed of PVB resin and silicone resin, wherein the PVB resin comprises the following components in percentage by mass: silicone = 1-3: 7-9;

the addition amount of the resin is 1.0 to 3.0 weight percent of the mass of the mixed powder.

8. The method for preparing the high-strength low-loss soft magnetic alloy composite material according to claim 1, which is characterized in that: the pressure of the compression molding is 1500-2500 MPa.

9. The method for preparing the high-strength low-loss soft magnetic alloy composite material according to claim 1, which is characterized in that: the sintering process is that the sintering is carried out under normal pressure in air atmosphere and then the sintering is carried out under pressure in protective atmosphere; the normal pressure sintering process comprises the following steps: the temperature is kept for 1 to 3 hours at 120 to 150 ℃ and then for 1 to 4 hours at 320 to 360 ℃, and when the pressure sintering is carried out, the air pressure in the furnace is kept at 20 to 100MPa before 700 ℃, then the temperature is raised to 700 to 750 ℃, the temperature is kept for 0.5 to 1 hour, and the pressure in the heat preservation process is controlled to be 10 to 30MPa.

10. A high strength low loss soft magnetic alloy composite material prepared by the method of any one of claims 1-9.