A low-impedance inductor and a preparation method and application thereof

Abstract

The application provides a low-impedance inductor and a preparation method and application thereof. The low-impedance inductor comprises a magnetic middle column with recesses; the volume of the recessed part accounts for 1-10% of the volume of the magnetic middle column; the preparation method comprises the following steps: firstly, mixing magnetic powder and glue to obtain mixed raw materials; then, carrying out coating granulation and screening treatment in sequence, and placing the magnetic middle column with recesses in a mold to carry out first pressing treatment to obtain the magnetic middle column with recesses; after the first solidification treatment of the magnetic middle column, the conductor coil is assembled, and then the second pressing treatment and the second solidification treatment are carried out in sequence to obtain a semi-finished product; and finally, the semi-finished product is subjected to insulation protection, laser paint stripping and electroplating in sequence to obtain the low-impedance inductor. The magnetic middle column with recesses in the low-impedance inductor can effectively reduce the deformation degree of the conductor coil, and further reduce the direct current impedance of the inductor.

Description

Technical Field

[0001] This invention relates to the field of inductor technology, and in particular to a low-impedance inductor, its preparation method, and its application. Background Technology

[0002] Molded inductors can operate continuously under high current conditions and provide stable power to the CPU. As electronic products become smaller and more powerful, electronic components are also developing towards smaller size and higher power. How to fabricate inductors with lower impedance in a smaller volume is an important research direction in the field of inductor fabrication.

[0003] CN111508694A discloses an ultra-low impedance thermoforming inductor and its manufacturing method. The inductor includes an inductor-coated insulator and a set of inductor functional components embedded inside the inductor-coated insulator. The inductor functional components are composed of a magnetic core and a flat coil. In the thermoforming state of the inductor-coated insulator and the inductor functional components, the inductor-coated insulator covers the outer periphery of the inductor functional components, and the two leads of the flat coil protrude from one end face of the inductor-coated insulator. By using thermoforming instead of cold-pressing and using flat coils instead of round coils, the insulation performance of the inductor is greatly improved, and the stability of the inductor is enhanced. The inductor can withstand a higher maximum current, has lower AC loss in its practical application, and maximizes the overall energy-saving effect of the device.

[0004] CN202183292U discloses an improved integrally molded inductor, which includes a coil, a magnetic solid body, and two electrode feet. The coil is embedded in the magnetic solid body. One end of each electrode foot is a first end, and the other end is a second end. The first ends of the two electrode feet are respectively embedded in the magnetic solid body, and the two electrode feet are respectively welded to the two ends of the coil. The disclosure also discloses a molding process after coil welding. However, welding the coil to the terminals introduces contact resistance, leading to an increase in DC resistance. Furthermore, deformation of the coil and terminals during molding further increases the DC resistance.

[0005] CN108648901A discloses an electronic component and a method for manufacturing an inductor. The electronic component includes: a body; a conductive element disposed in the body, wherein at least a portion of a terminal of the conductive element is exposed outside the body; a metal foil with an adhesive material on its bottom surface, the metal foil being adhered to the body by the adhesive material and covering a first portion of the terminal of the conductive element, wherein a second portion of the terminal of the conductive element is not covered by the metal foil and the adhesive material; and a first metal layer covering the metal foil and covering a second portion of the terminal of the conductive element, wherein the first metal layer is electrically connected to the second portion of the terminal of the conductive element for electrically connecting to an external circuit. Furthermore, it was disclosed that the T-core process was used to wind the coil on the T-core, and the inside and bottom of the coil were protected by the T-core during pressing. However, the T-core will still be compressed and deformed during the pressing process, and the coil will still have a certain degree of outward expansion. Moreover, the coil deformation will vary greatly under different design conditions, which will bring great inconvenience to design and production.

[0006] Therefore, it is of great significance to develop a low-impedance inductor with a simple preparation method that reduces coil deformation during the pressing process and to develop its preparation method. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a low impedance inductor, its preparation method and application. By adding a depression to the surface of the magnetic column, the deformation of the conductor coil is reduced, thereby reducing the DC impedance of the inductor. The preparation method is simple and suitable for large-scale application.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a low-impedance inductor, the low-impedance inductor comprising a magnetic post with a recess; the volume of the recessed portion accounts for 1% to 10% of the volume of the magnetic post.

[0010] The low-impedance inductor of this invention has a recessed surface on the magnetic core, with the recessed portion accounting for 1% to 10% of the volume of the magnetic core. This recess can alter the stress state of the conductor coil during pressing, improve the degree of conductor coil compression deformation, and thus reduce conductor coil deformation and DC impedance. If the volume of the recessed portion is too small or too large relative to the volume of the magnetic core, the DC impedance of the final inductor will increase.

[0011] In this invention, the volume of the recessed portion accounts for 1% to 10% of the volume of the magnetic central column, for example, it can be 1%, 3%, 5%, 8%, 9% or 10%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0012] Preferably, the cross-sectional shape of the magnetic central column includes any one of a circle, a square, an ellipse, or a racetrack shape.

[0013] Preferably, the shape of the recess includes any one or a combination of at least two of the following: groove, opening, pit, or thread. Typical but non-limiting combinations include a combination of groove and opening, a combination of pit and thread, a combination of opening and pit, or a combination of thread, groove, and opening.

[0014] Preferably, a conductor coil is disposed on the outer side of the magnetic central column; a schematic diagram of the conductor coil is shown below. Figure 1 As shown.

[0015] Preferably, the conductor coil is made of at least one strand of wire, which includes round wire or flat wire.

[0016] Preferably, the conductor coil is made of metal.

[0017] In a second aspect, the present invention also provides a method for preparing a low-impedance inductor as described in the first aspect, the method comprising the following steps:

[0018] (1) Mix the magnetic powder with the adhesive to obtain the mixed raw material;

[0019] (2) After the mixed raw materials are coated, granulated and screened in sequence, they are placed in a mold for the first pressing process to obtain a magnetic column with a concave shape.

[0020] (3) After the magnetic central column undergoes the first curing treatment, a conductor coil is assembled, and then the second pressing treatment and the second curing treatment are carried out in sequence to obtain a semi-finished product;

[0021] (4) The semi-finished product is subjected to insulation protection, laser stripping and electroplating in sequence to obtain the low impedance inductor.

[0022] The low-impedance inductor preparation method of this invention involves a first pressing in a mold, resulting in a magnetic central pillar with a certain volume of indentation. This alters the stress state of the conductor coil during the first pressing, improves the degree of conductor coil compression deformation, thereby reducing coil deformation and lowering the DC impedance of the inductor. The preparation method of this invention, through two pressing processes and two curing processes, yields an inductor with low DC impedance. The process is simple and has the potential for large-scale application.

[0023] Preferably, the mass of the adhesive in step (1) accounts for 1% to 5% of the mass of the mixed raw materials, for example, it can be 1%, 1.3%, 2%, 3%, 4% or 5%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] Preferably, the mesh size of the sieve in the sieving process described in step (2) is 60 to 250 mesh, for example, it can be 60 mesh, 80 mesh, 100 mesh, 120 mesh, 150 mesh, 200 mesh or 250 mesh, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] Preferably, the pressure of the first pressing process is 3 to 10 t / cm. 2 For example, it could be 3t / cm 2 4t / cm 2 5t / cm 2 6t / cm 2 7t / cm 2 8t / cm 2 or 10t / cm 2 This applies to, but is not limited to, the listed values; other unlisted values ​​within this range also apply.

[0026] Preferably, the temperature of the first pressing process is 10 to 30°C, for example, it can be 10°C, 15°C, 20°C, 25°C, 28°C or 30°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the time for the first pressing process is 1 to 10 seconds, for example, it can be 1 second, 2 seconds, 3 seconds, 5 seconds, 7 seconds, 9 seconds or 10 seconds, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the volume of the recessed portion accounts for 1% to 10% of the volume of the magnetic central column, for example, it can be 1%, 3%, 5%, 8%, 9% or 10%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] Preferably, the density of the magnetic central column is 5.5–7.5 g / cm³. 3 For example, it could be 5.5 g / cm³. 3 5.8g / cm 3 6g / cm 3 6.5g / cm 3 7g / cm 3 Or 7.5g / cm 3 This applies to, but is not limited to, the listed values; other unlisted values ​​within this range also apply.

[0030] Preferably, the density of the magnetic central column in this invention is 5.5–7.5 g / cm³. 3This ensures that the DC impedance of the final inductor is low. If the density of the magnetic pillars is too high or too low, the DC impedance of the final inductor will increase.

[0031] Preferably, the temperature of the first curing treatment in step (3) is ≤210℃, for example, it can be 210℃, 200℃, 180℃, 150℃, 120℃ or 100℃, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] Preferably, the time for the first curing process is ≤10s, for example, it can be 10s, 9s, 8s, 5s, 4s or 2s, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] Preferably, the curing degree of the magnetic central column after the first curing treatment is 5% to 30%, for example, it can be 5%, 8%, 10%, 15%, 20%, 25% or 30%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] This invention controls the temperature of the first curing treatment to be ≤210℃ and the time of the first curing treatment to be ≤10s, so that the degree of curing of the magnetic column after the first curing treatment is 5-30%, ensuring that the magnetic column has a certain strength but is not completely cured.

[0035] Preferably, the pressure of the second pressing process in step (3) is 3 to 10 t / cm. 2 For example, it could be 3t / cm 2 4t / cm 2 5t / cm 2 6t / cm 2 7t / cm 2 8t / cm 2 or 10t / cm 2 This applies to, but is not limited to, the listed values; other unlisted values ​​within this range also apply.

[0036] Preferably, the temperature of the second pressing process is 50 to 300°C, for example, it can be 50°C, 80°C, 100°C, 150°C, 200°C, 250°C or 300°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] Preferably, the second pressing time is 0.5 to 5 minutes, for example, it can be 0.5 minutes, 1 minute, 2 minutes, 3 minutes, 4 minutes, 4.5 minutes or 5 minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, the temperature of the second curing treatment in step (3) is 150 to 200°C, for example, it can be 150°C, 155°C, 160°C, 170°C, 180°C or 200°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Preferably, the curing time of the second curing process is 0.5 to 3.0 hours, for example, it can be 0.5 hours, 1 hour, 1.2 hours, 1.4 hours, 1.5 hours, 1.6 hours, 2.0 hours or 3.0 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, the degree of curing of the semi-finished product is >90%, for example, it can be 90.5%, 91%, 92%, 95%, 97% or 99%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] Preferably, the thickness of the insulating layer in the insulating protection described in step (4) is 5 to 15 μm, for example, it can be 5 μm, 6 μm, 7 μm, 10 μm, 12 μm or 15 μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] Preferably, the electroplated metal layer in step (4) includes any one or a combination of at least two of Cu, Ni, or Sn layers, wherein typical but non-limiting combinations include a combination of Cu and Ni layers, a combination of Sn and Cu layers, or a combination of Ni, Sn, and Cu layers.

[0043] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0044] (1) Mix magnetic powder with adhesive to obtain a mixed raw material; the mass of the adhesive accounts for 1% to 5% of the mass of the mixed raw material;

[0045] (2) After the mixed raw materials are sequentially coated, granulated, and sieved, they are placed in a mold and subjected to a pressure of 3-10 t / cm. 2 The magnetic column is subjected to a first pressing treatment at a temperature of 10–30°C for 1–10 seconds to obtain a magnetic column with indentations. The mesh size of the sieve used in the sieving process is 60–250 mesh. The volume of the indented portion accounts for 1%–10% of the volume of the magnetic column. The density of the magnetic column is 5.5–7.5 g / cm³. 3 ;

[0046] (3) After the magnetic central column undergoes a first curing treatment at a temperature ≤210℃, a conductor coil is assembled, and then the magnetic central column is subjected to a pressure of 3~10t / cm.2 The magnetic column is subjected to a second pressing treatment at a temperature of 50–300℃ for 0.5–5 min and a second curing treatment at a temperature of 150–200℃ for 0.5–3.0 h to obtain a semi-finished product with a curing degree >90%; the time of the first curing treatment is ≤10 s; the curing degree of the magnetic column after the first curing treatment is 5–30%;

[0047] (4) The semi-finished product is subjected to insulation protection, laser stripping and electroplating in sequence to obtain the low impedance inductor.

[0048] Thirdly, the present invention also provides an application of the low-impedance inductor as described in the first aspect in the power supply of a central processing unit.

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] The method for preparing low-impedance inductors provided by this invention has a simple process flow. The magnetic central column with a specific recessed volume in the prepared low-impedance inductor can effectively reduce the deformation of the conductor coil, thereby reducing the DC impedance of the inductor, and has the prospect of wide-ranging application. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of a low-impedance inductor with a circular recess on the magnetic column.

[0052] Figure 2 This is a schematic diagram of a low-impedance inductor with a square recess on the magnetic center post.

[0053] Figure 3 This is a schematic diagram of a magnetic column with a central recess in the low-impedance inductor provided by the present invention.

[0054] Figure 4 This is a schematic diagram of a low-impedance inductor provided by the present invention, in which the magnetic column has vertical grooves.

[0055] Figure 5 This is a schematic diagram of the conductor coil in the low-impedance inductor provided by the present invention.

[0056] Figure 6 This is a cross-sectional view of the magnetic central column and conductor coil provided by the present invention.

[0057] Figure 7 This is a cross-sectional view of the finished low-impedance inductor provided by the present invention.

[0058] Figure 8 This is a schematic diagram of the finished low-impedance inductor provided by the present invention. Detailed Implementation

[0059] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0060] The schematic diagram of the magnetic pillar with circular, square, centrally recessed, and vertically striped recesses on the magnetic core of the low-impedance inductor provided by this invention is shown below. Figures 1-4 As shown.

[0061] A schematic diagram of the conductor coil in the low-impedance inductor provided by this invention is shown below. Figure 5 As shown, a cross-sectional view of the magnetic center column and the conductor coil is as follows. Figure 6 As shown, a cross-sectional view of the finished low-impedance inductor is as follows. Figure 7 As shown in the diagram, the finished low-impedance inductor is as follows: Figure 8 As shown.

[0062] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0063] Example 1

[0064] This embodiment provides a method for fabricating a low-impedance inductor, the method comprising the following steps:

[0065] (1) A magnetic powder made by mixing amorphous alloy powder and alloy powder in a mass ratio of 4:6 is mixed with epoxy resin adhesive to obtain a mixed raw material; the mass of the adhesive accounts for 2% of the mass of the mixed raw material.

[0066] (2) After the mixed raw materials are sequentially coated, granulated, and sieved, they are placed in a mold and subjected to a pressure of 5.5 t / cm. 2 The magnetic column with indentations is obtained by a first pressing process at 25°C for 2.0 seconds; the mesh size of the sieve used in the sieving process is 120 mesh; the volume of the indented portion accounts for 1.5% of the volume of the magnetic column; the density of the magnetic column is 5.9 g / cm³. 3

[0067] (3) After the magnetic central column undergoes a first curing treatment at a temperature of 210℃, a conductor coil is assembled, and then subjected to a pressure of 5.0t / cm. 2 The product undergoes a second pressing process at 170℃ for 90 seconds and a second curing process at 180℃ for 1.5 hours to obtain a semi-finished product with a curing degree of >95%.

[0068] The curing time for the first curing process is 10 seconds; the curing degree of the magnetic central column after the first curing process is 15%.

[0069] (4) The semi-finished product is subjected to insulation protection, laser stripping and electroplating in sequence to obtain the low impedance inductor; the thickness of the insulation layer in the insulation protection is 10μm; the electroplated metal layer includes Cu layer, Ni layer and Sn layer from the inside to the outside.

[0070] Example 2

[0071] This embodiment provides a method for preparing a low-impedance inductor. The preparation method is the same as in Embodiment 1, except that the volume of the recessed portion accounts for 2.0% of the volume of the magnetic cylinder.

[0072] Example 3

[0073] This embodiment provides a method for preparing a low-impedance inductor. The preparation method is the same as in Embodiment 1, except that the volume of the recessed portion accounts for 2.5% of the volume of the magnetic cylinder.

[0074] Example 4

[0075] This embodiment provides a method for preparing a low-impedance inductor. The preparation method is the same as in Embodiment 1, except that the volume of the recessed portion accounts for 10% of the volume of the magnetic cylinder.

[0076] Example 5

[0077] This embodiment provides a method for preparing a low-impedance inductor, wherein the density of the magnetic column in step (2) is 3 g / cm³. 3 Except for the above, everything else is the same as in Example 1.

[0078] Example 6

[0079] This embodiment provides a method for preparing a low-impedance inductor, wherein the density of the magnetic column in step (2) is 7.8 g / cm³. 3 Except for the above, everything else is the same as in Example 1.

[0080] Example 7

[0081] This embodiment provides a method for preparing a low impedance inductor. Except for the curing degree of the magnetic central column after the first curing treatment in step (3) being 2%, the preparation method is the same as that in Example 1.

[0082] Example 8

[0083] This embodiment provides a method for preparing a low impedance inductor. Except for the curing degree of the magnetic central column after the first curing treatment in step (3) being 35%, the preparation method is the same as in embodiment 1.

[0084] Comparative Example 1

[0085] This comparative example provides a method for preparing an inductor. The method is identical to that of Example 1, except that the treated mixed powder is directly placed inside a conductor coil and subjected to a second pressing process. Specifically, it includes the following steps:

[0086] (1) A magnetic powder made by mixing amorphous alloy powder and alloy powder in a mass ratio of 4:6 is mixed with epoxy resin adhesive to obtain a mixed raw material; the mass of the adhesive accounts for 2% of the mass of the mixed raw material.

[0087] (2) After the mixed raw materials are sequentially coated, granulated, and sieved, they are placed inside a conductor coil and subjected to a pressure of 5.0 t / cm. 2 After pressing at 170℃ for 90 seconds, the low-impedance inductor is obtained by sequentially performing insulation protection, laser stripping, and electroplating. The insulation layer in the insulation protection is 10μm thick. The electroplated metal layer includes a Cu layer, a Ni layer, and a Sn layer from the inside out.

[0088] Comparative Example 2

[0089] This comparative example provides a method for preparing an inductor. The method is identical to that of Example 1 except for the absence of the first and second curing treatments, and specifically includes the following steps:

[0090] (1) A magnetic powder made by mixing amorphous alloy powder and alloy powder in a mass ratio of 4:6 is mixed with epoxy resin adhesive to obtain a mixed raw material; the mass of the adhesive accounts for 2% of the mass of the mixed raw material.

[0091] (2) After the mixed raw materials are sequentially coated, granulated, and sieved, they are placed in a mold and subjected to a pressure of 5.5 t / cm. 2 The magnetic column with indentations is obtained by a first pressing process at 25°C for 2.0 seconds; the mesh size of the sieve used in the sieving process is 120 mesh; the volume of the indented portion accounts for 1.5% of the volume of the magnetic column; the density of the magnetic column is 5.9 g / cm³. 3

[0092] (3) After the magnetic central column is assembled with the conductor coil, it is subjected to a pressure of 5.0 t / cm. 2 A second pressing process at 170℃ for 90 seconds yields a semi-finished product.

[0093] (4) The semi-finished product is subjected to insulation protection, laser stripping and electroplating in sequence to obtain the low impedance inductor; the thickness of the insulation layer in the insulation protection is 10μm; the electroplated metal layer includes Cu layer, Ni layer and Sn layer from the inside to the outside.

[0094] Comparative Example 3

[0095] This comparative example provides a method for preparing a low-impedance inductor. The preparation method is the same as in Example 1, except that the volume of the recessed portion accounts for 0.3% of the volume of the magnetic cylinder.

[0096] Comparative Example 4

[0097] This comparative example provides a method for preparing a low-impedance inductor. The preparation method is the same as in Example 1, except that the volume of the recessed portion accounts for 13% of the volume of the magnetic cylinder.

[0098] The DC impedance of the inductors obtained in the above embodiments and comparative examples was measured using a DC resistance tester (AX-1152D), and the results are shown in Table 1.

[0099] Table 1

[0100]

[0101]

[0102] As can be seen from Table 1:

[0103] (1) As can be seen from Examples 1 to 4, the low impedance inductor prepared by the present invention can achieve a DC impedance of less than 30.2mΩ, which has the prospect of wide application.

[0104] (2) It can be seen from the combined examples 1 and 5-8 that when the density of the magnetic column in step (2) is too low or too high, or the degree of curing of the magnetic column after the first curing treatment in step (3) is too low or too high, the DC impedance of the final inductor will increase.

[0105] (3) It can be seen from the combined example 1 and comparative examples 1 to 2 that comparative example 1 directly places the processed mixed powder into the conductor coil and only performs the second pressing process, while comparative example 2 does not perform the first curing process and the second curing process. The conductor coil has a poor stress condition and is prone to deformation, which leads to an increase in the DC impedance of the inductor.

[0106] (4) It can be seen from the combined embodiment 1 and comparative examples 3 to 4 that when the volume of the recessed part is too low or too high as a proportion of the volume of the magnetic central column, the degree of deformation of the conductor coil increases significantly, which in turn leads to an increase in the DC impedance of the inductor.

[0107] In summary, the low-impedance inductor preparation method provided by this invention has a simple process flow, and the magnetic central column with a specific recessed volume in the prepared low-impedance inductor can effectively reduce the degree of conductor coil deformation, thereby reducing the DC impedance of the inductor, and has the prospect of wide-ranging application.

[0108] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A low-impedance inductor, characterized in that, The low-impedance inductor includes a magnetic post with a recess; the recess is disposed on the surface of the magnetic post; the volume of the recessed portion accounts for 1% to 10% of the volume of the magnetic post; the density of the magnetic post is 5.5 to 7.5 g / cm³. 3 The low-impedance inductor can effectively reduce the deformation of the conductor coil, and its DC impedance is below 30.2mΩ.

2. The low-impedance inductor according to claim 1, characterized in that, The cross-sectional shape of the magnetic central column includes any one of the following: circular, square, elliptical, or racetrack-shaped.

3. The low-impedance inductor according to claim 1, characterized in that, The shape of the recess includes any one or a combination of at least two of the following: groove, pit, or thread.

4. The low-impedance inductor according to claim 1, characterized in that, A conductor coil is provided on the outside of the magnetic central column.

5. The low-impedance inductor according to claim 4, characterized in that, The conductor coil is made of at least one strand of wire, which may be round or flat.

6. The low-impedance inductor according to claim 5, characterized in that, The conductor coil is made of metal.

7. A method for preparing a low-impedance inductor as described in any one of claims 1 to 6, characterized in that, The preparation method includes the following steps: (1) Mix the magnetic powder with the glue to obtain a mixed raw material; (2) After the mixed raw materials are coated, granulated and screened in sequence, they are placed in a mold for the first pressing process to obtain a magnetic central column with a concave shape. (3) After the magnetic central column undergoes the first curing treatment, a conductor coil is assembled, and then the second pressing treatment and the second curing treatment are carried out in sequence to obtain a semi-finished product; (4) The semi-finished product is subjected to insulation protection, laser stripping and electroplating in sequence to obtain the low impedance inductor.

8. The preparation method according to claim 7, characterized in that, The adhesive used in step (1) accounts for 1% to 5% of the mass of the mixed raw materials.

9. The preparation method according to claim 7, characterized in that, In step (2), the mesh size of the sieve is 60-250.

10. The preparation method according to claim 7, characterized in that, In step (2), the pressure of the first pressing process is 3~10 t / cm. 2 .

11. The preparation method according to claim 7, characterized in that, In step (2), the temperature of the first pressing process is 10~30℃.

12. The preparation method according to claim 7, characterized in that, Step (2) The first compression process takes 1 to 10 seconds.

13. The preparation method according to claim 7, characterized in that, Step (3) The temperature of the first curing treatment is ≤210℃.

14. The preparation method according to claim 7, characterized in that, Step (3) The time for the first curing process is ≤10s.

15. The preparation method according to claim 7, characterized in that, Step (3) The curing degree of the magnetic central column after the first curing treatment is 5~30%.

16. The preparation method according to claim 7, characterized in that, In step (3), the pressure of the second pressing process is 3~10 t / cm. 2 .

17. The preparation method according to claim 7, characterized in that, In step (3), the temperature of the second pressing process is 50~300℃.

18. The preparation method according to claim 7, characterized in that, Step (3) The second pressing process takes 0.5 to 5 minutes.

19. The preparation method according to claim 7, characterized in that, In step (3), the temperature of the second curing process is 150~200℃.

20. The preparation method according to claim 7, characterized in that, The curing time for step (3) is 0.5~3.0h.

21. The preparation method according to claim 7, characterized in that, The degree of curing of the semi-finished product in step (3) is >90%.

22. The preparation method according to claim 7, characterized in that, The preparation method includes the following steps: (1) Mix the magnetic powder with the adhesive to obtain a mixed raw material; the mass of the adhesive accounts for 1% to 5% of the mass of the mixed raw material; (2) After the mixed raw materials are successively coated, granulated and screened, they are placed in a mold and subjected to a pressure of 3~10t / cm. 2 The magnetic column is subjected to a first pressing treatment at a temperature of 10~30℃ for 1~10s to obtain a magnetic column with indentations; the mesh size of the sieve used in the sieving process is 60~250 mesh; the volume of the indented portion accounts for 1%~10% of the volume of the magnetic column; the density of the magnetic column is 5.5~7.5 g / cm³. 3 ; (3) After the magnetic central column undergoes a first curing treatment at a temperature ≤210℃, a conductor coil is assembled, and then the magnetic central column is subjected to a pressure of 3~10t / cm. 2 The magnetic column undergoes a second pressing process at 50-300℃ for 0.5-5 minutes and a second curing process at 150-200℃ for 0.5-3.0 hours to obtain a semi-finished product with a curing degree >90%; the first curing process takes ≤10 seconds; and the curing degree of the magnetic column after the first curing process is 5-30%. (4) The semi-finished product is subjected to insulation protection, laser stripping and electroplating in sequence to obtain the low impedance inductor.

23. The application of a low-impedance inductor as described in any one of claims 1 to 6 in the power supply of a central processing unit.

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