Alloy material for inductors, method for producing the same, and inductor

Abstract

The application discloses an alloy material for inductance, a preparation method thereof and an inductance. The particle of the alloy material for inductance is a core-shell structure, the shell is attached to the outer surface of the core, the core is an FeSiCr alloy particle, and the shell is a Cr2O3 layer. A relationship between the median particle size D50 of the particle of the alloy material and the thickness T of the Cr2O3 layer satisfies the following conditions: when 3 mu m <= D50 < 5 mu m, the percentage of T to D50 is in the range of [0.98%, 2.49%]; when 5 mu m <= D50 < 10 mu m, the percentage of T to D50 is in the range of (2.49%, 3.95%]; and when 10 mu m <= D50 < 25 mu m, the percentage of T to D50 is in the range of (3.95%, 8.56%). The application achieves a better balance between the magnetic permeability and the insulation voltage resistance of the alloy material, and improves the comprehensive performance of the inductance.

Description

Technical Field

[0001] The present invention relates to the field of inductor components, and in particular to an alloy material for inductance, a preparation method thereof, and an inductor. Background Art

[0002] Currently, the performance of alloy materials used in power inductors often fails to reach the theoretical value of the material. In the existing technology, the insulation coating of most alloy materials is mainly achieved through the following methods: 1. Coating a layer of organic resin material on the surface of the alloy particles to form an insulating layer. However, the thermal stability of resin materials is poor and they are easily decomposed or softened at high temperatures, affecting the insulation effect of the magnetic core. In addition, the increased thickness of the resin material will lead to a decrease in the inductance performance of the magnetic core, and uneven coating will affect the close packing between particles, resulting in performance degradation. 2. Generating an inorganic oxide film (such as SiO2, Al2O3, etc.) on the surface of the alloy particles through chemical or physical methods to enhance the insulation properties. This process is relatively complex and easily leads to increased costs. 3. After coating alloy powders of different particles, they are mixed and sintered to form a multi-layer structure to achieve the insulation effect. This method is prone to cracking or shedding of the oxide layer during the sintering process, affecting the insulation effect, and the coating of the multi-layer structure increases the difficulty and cost of sintering. Existing alloy materials for inductors have the problem of insufficient balance between insulation withstand voltage and magnetic permeability.

[0003] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0004] In order to make up for the deficiencies of the prior art, the present invention provides an alloy material for an inductor, a preparation method thereof, and an inductor.

[0005] The present invention adopts the following technical solutions:

[0006] In a first aspect, an alloy material for an inductor is provided, wherein particles of the alloy material have a core-shell structure, the shell being attached to the outer surface of the core, the core being a FeSiCr alloy particle, and the shell being a Cr2O3 layer, wherein the median particle size D50 of the particles of the alloy material and the thickness T of the Cr2O3 layer satisfy the following relationship: when 3 μm ≤ D50 < 5 μm, the percentage of T in D50 is in the range of [0.98%, 2.49%]; when 5 μm ≤ D50 < 10 μm, the percentage of T in D50 is in the range of (2.49%, 3.95%]; and when 10 μm ≤ D50 < 25 μm, the percentage of T in D50 is in the range of (3.95%, 8.56%]).

[0007] In a second aspect, a method for preparing the alloy material for inductance according to the first aspect is provided, comprising the following steps:

[0008] (1) Using FeSiCr alloy powder as raw material, the surface of the powder is cleaned to remove the naturally oxidized part of the powder surface;

[0009] (2) Sintering the FeSiCr alloy powder cleaned in step (1) in an inert atmosphere containing oxygen to form a Cr2O3 layer on the particle surface to obtain the inductor alloy material, wherein the median particle size D50 of the inductor alloy material is in the range of 3 to 25 μm.

[0010] In a third aspect, an inductor is provided, which includes the alloy material for inductor described in the first aspect.

[0011] The present invention has the following beneficial effects: It solves the problem of poor balance between insulation withstand voltage and magnetic permeability in existing inductor alloy materials. By controlling the ratio between the alloy's median particle size D50 and the thickness T of the Cr2O3 layer, the provided inductor alloy material achieves a magnetic permeability closer to the theoretical value while also maintaining excellent insulation withstand voltage. This invention achieves an optimal balance between the alloy's magnetic permeability and insulation withstand voltage, thereby improving the overall performance of the inductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a scanning electron microscope image of the alloy material in Example 1 of the present invention;

[0013] Figure 2 3 is a scanning electron microscope image of the alloy material in Example 2 of the present invention. DETAILED DESCRIPTION

[0014] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is merely illustrative and is not intended to limit the scope and application of the present invention. In the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0015] A specific embodiment of the present invention provides an alloy material for inductance, wherein the particles of the alloy material have a core-shell structure, the shell is attached to the outer surface of the core, the core is a FeSiCr alloy particle, and the shell is a Cr2O3 layer, wherein the median particle size D50 of the particles of the alloy material and the thickness T of the Cr2O3 layer satisfy the following relationship: when 3μm≤D50<5μm, the percentage of T in D50 is in the range of [0.98%, 2.49%]; when 5μm≤D50<10μm, the percentage of T in D50 is in the range of (2.49%, 3.95%]; when 10μm≤D50<25μm, the percentage of T in D50 is in the range of (3.95%, 8.56%]).

[0016] In some embodiments, when the median particle size D50 of the alloy material particles is 3.04 μm, the percentage of T in D50 is in the range of 0.99% to 1.64%; when the median particle size D50 of the alloy material particles is 5.14 μm, the percentage of T in D50 is in the range of 2.53% to 2.92%; when the median particle size D50 of the alloy material particles is 10.50 μm, the percentage of T in D50 is in the range of 4.29% to 5.24%; when the median particle size D50 of the alloy material particles is 21.7 μm, the percentage of T in D50 is in the range of 7.14% to 8.53%.

[0017] The specific embodiment of the present invention further provides a method for preparing the alloy material for inductance, which comprises the following steps:

[0018] (1) Using FeSiCr alloy powder as raw material, the surface of the powder is cleaned to remove the naturally oxidized part of the powder surface;

[0019] (2) Sintering the FeSiCr alloy powder cleaned in step (1) in an inert atmosphere containing oxygen to form a Cr2O3 layer on the particle surface to obtain the inductor alloy material, wherein the median particle size D50 of the inductor alloy material is in the range of 3 to 25 μm.

[0020] By directly sintering the FeSiCr alloy powder to form a dense Cr2O3 layer on its surface, the insulation performance of the material can be effectively improved, and it has the following advantages: the Cr2O3 oxide layer formed by sintering is dense and uniform, and has high thermal stability; directly forming an oxide layer on the particle surface avoids the structural complexity of traditional coating, makes the particles stacked more closely, forms a uniform stacking structure, and also reduces air gaps; compared with other coating methods, the process flow of the method of the present invention is simpler, which helps to reduce production costs and improve the stability of the production process. In addition, the thickness of the Cr2O3 layer is controlled during sintering, thereby controlling the proportional relationship between the median particle size D50 of the particles of the alloy material and the thickness T of the Cr2O3 layer to meet the following requirements: Relationship: When 3μm≤D50<5μm, the percentage of T in D50 is in the range of [0.98%, 2.49%]; when 5μm≤D50<10μm, the percentage of T in D50 is in the range of (2.49%, 3.95%]; when 10μm≤D50<25μm, the percentage of T in D50 is in the range of (3.95%, 8.56%], which makes the electric field distribution inside the alloy material more uniform, achieves a better balance between magnetic permeability and insulation withstand voltage, and improves the comprehensive performance of the inductor. If the ratio between the median particle size D50 of the alloy material particles and the thickness T of the Cr2O3 layer is not within the above range, it is difficult to simultaneously improve the insulation withstand voltage performance and magnetic permeability of the inductor, which will affect the performance of the power inductor.

[0021] It is worth noting that during the sintering process, due to uneven powder distribution or local temperature differences, the Cr2O3 layer may not be fully formed on the surface of some alloy particles. This local unevenness is inevitable at the microscopic scale. Taking into account the errors in the actual process, it is expected that no more than 10wt% of the alloy particles will experience this situation. This deviation falls within the common error range in the manufacturing process and will not significantly affect the overall performance of the material.

[0022] In some embodiments, the cleaning in step (1) refers to cleaning the surface of the powder with an inert gas.

[0023] In some embodiments, in step (2), the thickness of the Cr2O3 layer is controlled by controlling at least one of the sintering temperature, the sintering time, and the oxygen concentration in the inert atmosphere, thereby controlling the proportional relationship between the median particle size D50 of the particles of the alloy material and the thickness T of the Cr2O3 layer.

[0024] In some embodiments, in step (2), the sintering temperature is 750-880° C. (preferably 800-880° C.), the sintering time is 0.5-3 h, and the oxygen concentration in the inert atmosphere is 21 vol% to 50 vol%.

[0025] In some embodiments, the inert atmosphere containing oxygen contains oxygen and further contains at least one of nitrogen and argon.

[0026] In some embodiments, the Cr content in the FeSiCr alloy powder in step (1) is ≥2 wt %; preferably, in step (1), the Cr content in the FeSiCr alloy powder is ≥2 wt % and ≤4 wt %.

[0027] In some embodiments, the FeSiCr alloy powder of step (1) contains 91.5 wt%-93.5 wt% of Fe, 4.5 wt% of Si and 2.0 wt%-4.0 wt% of Cr.

[0028] In some embodiments, in step (1), the FeSiCr alloy powder contains 91.5 wt% of Fe, 4.5 wt% of Si and 4.0 wt% of Cr; or the FeSiCr alloy powder contains 92.5 wt% of Fe, 4.5 wt% of Si and 3.0 wt% of Cr; or the FeSiCr alloy powder contains 93.5 wt% of Fe, 4.5 wt% of Si and 2.0 wt% of Cr.

[0029] In some embodiments, the particle size distribution D50 of the FeSiCr alloy powder in step (1) is in the range of 2 to 20 μm.

[0030] A specific embodiment of the present invention further provides an inductor, which includes the alloy material for inductor.

[0031] Specific embodiments of the present invention are further described below.

[0032] Example 1

[0033] The preparation method of the alloy material comprises the following steps:

[0034] 1. Select FeSiCr alloy powder with a particle size distribution (median particle size) of D'50 = 3 μm (the mass percentages of the components are as follows: Fe: 91.5%, Si: 4.5%, Cr: 4.0%) to ensure uniform distribution of powder particles and reduce the impact of fine particle impurities. Use inert gas to clean the powder surface to remove naturally oxidized areas and ensure the uniformity and consistency of the oxidized Cr2O3 layer.

[0035] 2. Under nitrogen atmosphere, the cleaned FeSiCr alloy powder was heated to 800°C at a heating rate of 5°C / min in an environment with an oxygen volume fraction of 30 vol%, kept at this temperature for 1 hour (i.e., the sintering and oxidation time was 1 hour), and naturally cooled to room temperature to obtain an alloy material with a median particle size D50 of 3.04 μm and a Cr2O3 layer thickness T of 30-50 nm. Figure 1 As shown, after scanning electron microscope analysis and measurement, the thickness of the Cr2O3 layer is uniform and flat, with a thickness of 30-50nm, and the percentage of the thickness T of the Cr2O3 layer to D50 is in the range of 0.99% to 1.64%.

[0036] 3. Add an appropriate amount of adhesive to the alloy material obtained in step 2, place it in an 8×5×2 mm mold, and apply a pressure of 900 MPa to compact the powder. Place the pressed magnetic ring into a sintering mold, keep it sealed, and introduce inert gas to sinter it at 850°C for 9 hours. This sintering temperature ensures that the Cr2O3 insulating layer between the particles is not damaged during the sintering process and helps form a stable interface between the particles, making the magnetic core more compact.

[0037] 4. The performance of the formed magnetic ring was tested. The test results are shown in Table 1.

[0038] Comparative Example 1

[0039] The difference from Example 1 is that the sintering and oxidation time in step 2 is 20 minutes. Scanning electron microscopy analysis and measurement show that the thickness of the Cr2O3 layer on the surface of the alloy material obtained in Comparative Example 1 is 10-20 nm, the median particle size D50 of the alloy material particles is 3.01 μm, and the thickness T of the Cr2O3 layer accounts for D50 in the range of 0.33% to 0.66%. The other steps are the same as in Example 1. The performance of the magnetic ring formed from the alloy material of Comparative Example 1 was tested, and the test results are shown in Table 1.

[0040] Comparative Example 2

[0041] The difference from Example 1 is that the sintering and oxidation time in step 2 is 5 hours. Scanning electron microscopy analysis and measurement show that the thickness of the Cr2O3 layer on the surface of the alloy material obtained in Comparative Example 2 is 100-120 nm, the median particle size D50 of the alloy material particles is 3.11 μm, and the thickness T of the Cr2O3 layer accounts for D50 as a percentage of 3.22% to 3.86%. The other steps are the same as in Example 1. The performance of the magnetic ring formed from the alloy material of Comparative Example 2 was tested, and the test results are shown in Table 1.

[0042] Table 1:

[0043] project Magnetic permeability Insulation (MΩ) Withstand voltage (V) Comparative Example 1 118 20 146 Example 1 110 1800 1401 Comparative Example 2 87 2000 1787

[0044] As can be seen from Table 1, the sample of Example 1 has a magnetic permeability of 110, an insulation of 1800 MΩ, and a withstand voltage of 1401 V. The magnetic permeability is close to 92% of the theoretical value (the theoretical value of the magnetic permeability of the material in this example is 120). While meeting the insulation and withstand voltage requirements, the magnetic permeability of the sample of Example 1 is closer to the theoretical value. However, the insulation and withstand voltage of the sample of Comparative Example 1 is poor, and the magnetic permeability of Comparative Example 2 is low. Therefore, Example 1 achieves excellent insulation and good magnetic permeability values, and its performance meets the design requirements.

[0045] Example 2

[0046] The preparation method of the alloy material comprises the following steps:

[0047] 1. Select FeSiCr alloy powder with a particle size distribution (median particle size) D'50=5 μm. The mass percentage of each component in the alloy powder and the pretreatment are the same as those in Example 1.

[0048] 2. The difference from step 2 of Example 1 is that the sintering oxidation temperature is set to 850°C and the sintering oxidation time is set to 1.5 hours, and the alloy material has a median particle size D50 of 5.14 μm and a Cr2O3 layer thickness T of 130-150 nm. Figure 2 As shown, the thickness of the Cr2O3 layer is measured by scanning electron microscopy. The thickness of the Cr2O3 layer is uniform and flat, with a thickness of 130-150 nm. The percentage of the thickness T of the Cr2O3 layer to D50 is in the range of 2.53% to 2.92%.

[0049] 3. The difference from step 3 of Example 1 is that the alloy material obtained in step 2 is pressed into shape and then sintered at a sintering temperature of 870° C. for 9 hours.

[0050] 4. The formed magnetic ring was tested, and the test results are shown in Table 2.

[0051] Comparative Example 3

[0052] The difference from Example 2 is that the sintering and oxidation time in step 2 is 20 minutes. Scanning electron microscopy analysis and measurement show that the thickness of the Cr2O3 layer on the surface of the alloy material obtained in Comparative Example 3 is 20-40 nm, the median particle size D50 of the alloy material particles is 5.03 μm, and the thickness T of the Cr2O3 layer accounts for D50 in the range of 0.40% to 0.80%. The other steps are the same as in Example 2. The performance of the magnetic ring formed from the alloy material of Comparative Example 3 was tested, and the test results are shown in Table 2.

[0053] Comparative Example 4

[0054] The difference from Example 2 is that the sintering and oxidation time in step 2 is 5 hours. Scanning electron microscopy analysis and measurement show that the thickness of the Cr2O3 layer on the surface of the alloy material obtained in Comparative Example 4 is 210-230 nm, the median particle size D50 of the alloy material particles is 5.22 μm, and the thickness T of the Cr2O3 layer accounts for D50 in the range of 4.02% to 4.41%. The other steps are the same as in Example 2. The performance of the magnetic ring formed from the alloy material of Comparative Example 4 was tested, and the test results are shown in Table 2.

[0055] Table 2:

[0056] project Magnetic permeability Insulation (MΩ) Withstand voltage (V) Comparative Example 3 113 410 104 Example 2 104 1969 1008 Comparative Example 4 73 2000 1316

[0057] As can be seen from Table 2, the magnetic permeability of the sample of Example 2 is 104, the withstand voltage reaches 1969V, and the magnetic permeability is close to 87% of the theoretical value (the theoretical value of the magnetic permeability of the material in this example is 120). The sample of Example 2 has a magnetic permeability closer to the theoretical value while meeting the insulation withstand voltage requirements, while the insulation withstand voltage of the sample of Comparative Example 3 is poor, and the magnetic permeability of Comparative Example 4 is low. Therefore, Example 2 achieves a good balance between insulation and magnetic permeability, ensuring the stability and withstand voltage performance of the product under working conditions.

[0058] Example 3

[0059] The preparation method of the alloy material comprises the following steps:

[0060] 1. Select FeSiCr alloy powder with a particle size distribution (median particle size) D'50=10 μm. The mass percentage of each component in the alloy powder and the pretreatment are the same as those in Example 1.

[0061] 2. The difference from step 2 of Example 1 is that the sintering oxidation temperature is set to 850°C, the sintering oxidation time is set to 2 hours, and the median particle size D50 of the alloy material particles is obtained to be 10.50 μm, the thickness T of the Cr2O3 layer is 450-550 nm, and the percentage of the thickness T of the Cr2O3 layer to D50 is in the range of 4.29% to 5.24%.

[0062] 3. The difference from step 3 of Example 1 is that the alloy material obtained in step 2 is pressed into shape and then sintered at a sintering temperature of 870° C. for 9 hours.

[0063] 4. The formed magnetic ring was tested. The test results are shown in Table 3.

[0064] Comparative Example 5

[0065] The difference from Example 3 is that the sintering and oxidation time in step 2 is 27 minutes. Scanning electron microscopy analysis and measurement show that the thickness of the Cr2O3 layer on the surface of the alloy material obtained in Comparative Example 5 is 150-250 nm, the median particle size D50 of the alloy material particles is 10.20 μm, and the thickness T of the Cr2O3 layer accounts for D50 in the range of 1.47% to 2.45%. The other steps are the same as in Example 3. The performance of the magnetic ring formed from the alloy material of Comparative Example 5 was tested, and the test results are shown in Table 3.

[0066] Comparative Example 6

[0067] The difference from Example 3 is that the sintering and oxidation time in step 2 is 6 hours. Scanning electron microscopy analysis and measurement show that the thickness of the Cr2O3 layer on the surface of the alloy material obtained in Comparative Example 6 is 950-1050 nm, the median particle size D50 of the alloy material particles is 11.00 μm, and the thickness T of the Cr2O3 layer accounts for D50 in the range of 8.64% to 9.55%. The other steps are the same as in Example 3. The performance of the magnetic ring formed from the alloy material of Comparative Example 6 was tested, and the test results are shown in Table 3.

[0068] Table 3:

[0069] project Magnetic permeability Insulation (MΩ) Withstand voltage (V) Comparative Example 5 110 271 104 Example 3 99 2000 1734 Comparative Example 6 71 2280 1960

[0070] As can be seen from Table 3, Example 3 achieves a good balance between insulation and magnetic permeability, ensuring the stability and voltage resistance of the product under working conditions.

[0071] Example 4

[0072] The preparation method of the alloy material comprises the following steps:

[0073] 1. A FeSiCr alloy powder with a particle size distribution (median particle size) of D'50 = 20 μm was selected. The mass percentage of each component in the alloy powder and the pretreatment were the same as those in Example 1.

[0074] 2. The difference from step 2 of Example 1 is that the sintering oxidation temperature is set to 880°C, the sintering oxidation time is set to 3 hours, and the median particle size D50 of the alloy material particles is obtained to be 21.7 μm, the thickness T of the Cr2O3 layer is 1550-1850 nm, and the percentage of the thickness T of the Cr2O3 layer to D50 is in the range of 7.14% to 8.53%.

[0075] 3. The difference from step 3 of Example 1 is that the alloy material obtained in step 2 is pressed into shape and then sintered at a sintering temperature of 870° C. for 9 hours.

[0076] 4. The formed magnetic ring was tested. The test results are shown in Table 4.

[0077] Comparative Example 7

[0078] The difference from Example 4 is that the sintering and oxidation time in step 2 is 25 minutes. Scanning electron microscopy analysis and measurement show that the thickness of the Cr2O3 layer on the surface of the alloy material obtained in Comparative Example 7 is 300-500 nm, the median particle size D50 of the alloy material particles is 20.4 μm, and the thickness T of the Cr2O3 layer accounts for D50 in the range of 1.47% to 2.45%. The other steps are the same as in Example 4. The performance of the magnetic ring formed from the alloy material of Comparative Example 7 was tested, and the test results are shown in Table 4.

[0079] Comparative Example 8

[0080] The difference from Example 4 is that the sintering and oxidation time in step 2 is 6 hours. Scanning electron microscopy analysis and measurement show that the thickness of the Cr2O3 layer on the surface of the alloy material obtained in Comparative Example 8 is 2400-2700 nm, the median particle size D50 of the alloy material particles is 22.5 μm, and the thickness T of the Cr2O3 layer accounts for D50 in the range of 10.67% to 12.00%. The other steps are the same as in Example 4. The performance of the magnetic ring formed from the alloy material of Comparative Example 8 was tested, and the test results are shown in Table 4.

[0081] Table 4:

[0082] project Magnetic permeability Insulation (MΩ) Withstand voltage (V) Comparative Example 7 117 196 301 Example 4 107 1743 1651 Comparative Example 8 83 1866 1731

[0083] As can be seen from Table 4, Example 4 achieves a good balance between insulation and magnetic permeability, ensuring the stability and voltage resistance of the product under working conditions.

[0084] The above embodiments optimize the magnetic permeability and insulation withstand voltage of the alloy material by regulating the thickness of the Cr2O3 layer and thus the ratio of the median particle size D50 of the alloy material particles to the thickness T of the Cr2O3 layer. Therefore, the alloy material of the present invention has a simple preparation process, higher stability, durability and electrical performance, and has high market competitiveness and application value.

[0085] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Persons skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features of different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of protection of the patent application.

Claims

1. An alloy material for inductance, characterized in that: The particles of the alloy material have a core-shell structure, the shell is attached to the outer surface of the core, the core is a FeSiCr alloy particle, and the shell is a Cr2O3 layer, wherein the median particle size D50 of the particles of the alloy material and the thickness T of the Cr2O3 layer satisfy the following relationship: when 3μm≤D50<5μm, 0.98%≤T accounts for ≤2.49% of D50; when 5μm≤D50<10μm, 2.49%<T accounts for ≤3.95% of D50; when 10μm≤D50<25μm, 3.95%<T accounts for ≤8.56% of D50.

2. The inductor alloy material according to claim 1, wherein: When the median particle size D50 of the particles of the alloy material is 3.04 μm, the percentage of T in D50 is in the range of 0.99% to 1.64%; when the median particle size D50 of the particles of the alloy material is 5.14 μm, the percentage of T in D50 is in the range of 2.53% to 2.92%; when the median particle size D50 of the particles of the alloy material is 10.50 μm, the percentage of T in D50 is in the range of 4.29% to 5.24%; when the median particle size D50 of the particles of the alloy material is 21.7 μm, the percentage of T in D50 is in the range of 7.14% to 8.53%.

3. A method for preparing the inductor alloy material according to any one of claims 1 to 2, characterized in that: The steps include: (1) Using FeSiCr alloy powder as raw material, clean the surface of the powder to remove the naturally oxidized part of the powder surface; (2) Sintering the FeSiCr alloy powder cleaned in step (1) in an inert atmosphere containing oxygen to form a Cr2O3 layer on the particle surface, thereby obtaining the inductor alloy material, wherein the median particle size D50 of the inductor alloy material is in the range of 3 to 25 μm.

4. The preparation method according to claim 3, wherein In step (2), the thickness of the Cr2O3 layer is controlled by controlling at least one of the sintering temperature, the sintering time and the oxygen concentration in the inert atmosphere, thereby controlling the proportional relationship between the median particle size D50 of the particles of the alloy material and the thickness T of the Cr2O3 layer.

5. The preparation method according to claim 4, wherein In step (2), the sintering temperature is 750-880° C., the sintering time is 0.5-3 h, and the oxygen concentration in the inert atmosphere is 21 vol%-50 vol%.

6. The preparation method according to claim 3, wherein The Cr content in the FeSiCr alloy powder of step (1) is ≥2wt%.

7. The preparation method according to claim 3, wherein In step (1), the Cr content in the FeSiCr alloy powder is ≥2wt% and ≤4wt%.

8. The preparation method according to claim 3, wherein The FeSiCr alloy powder in step (1) contains 91.5wt%-93.5wt% of Fe, 4.5wt% of Si and 2.0wt%-4.0wt% of Cr.

9. The preparation method according to claim 8, wherein In step (1), the FeSiCr alloy powder contains 91.5wt% of Fe, 4.5wt% of Si and 4.0wt% of Cr; or the FeSiCr alloy powder contains 92.5wt% of Fe, 4.5wt% of Si and 3.0wt% of Cr; or the FeSiCr alloy powder contains 93.5wt% of Fe, 4.5wt% of Si and 2.0wt% of Cr.

10. The preparation method according to claim 3, wherein The median particle size D50 of the FeSiCr alloy powder in step (1) is in the range of 2 to 20 μm.

11. An inductor, characterized in that: The invention comprises the alloy material for inductance according to any one of claims 1 to 2.

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