Soft magnetic composite, method for manufacturing soft magnetic composite, method for manufacturing inductor, and inductor

Abstract

The embodiment of the application relates to the technical field of inductance elements, in particular to a soft magnetic composite material, a preparation method of the soft magnetic composite material, a preparation method of an inductor and the inductor. The inductor can be prepared by sintering treatment of the soft magnetic composite material by using a sintering process. The first coating layer of the soft magnetic composite material is the main source of insulation performance of the soft magnetic composite material, and can effectively reduce the eddy current loss of the soft magnetic composite material. In the process of sintering treatment of the soft magnetic composite material to prepare the inductor, the ferromagnetic coating material of the second coating layer not only can play a role in protecting the first coating layer to reduce the phenomenon of cracking or falling off of the first coating layer in the sintering process, but also can play a role in engaging and bonding the solid pyrolysis product of the third coating layer, and improve the cracking or fracture of the inductor caused by pyrolysis of the organic insulating material of the third coating layer in the sintering process. The fourth coating layer is used for further reinforcing the insulation performance of the soft magnetic composite material.

Description

Technical Field

[0001] This application relates to the field of inductor technology, and in particular to a soft magnetic composite material, a method for preparing the soft magnetic composite material, a method for preparing an inductor, and an inductor. Background Technology

[0002] A chip inductor is a special type of molded inductor that is the core component of a chip power supply module. It provides power to the front end of the chip to maintain the normal operation of various chips in the motherboard and graphics card.

[0003] As chips continue to miniaturize, their voltages are decreasing, requiring increased current to maintain high power demands. This places higher demands on the chip inductor, the core component of the chip power supply module.

[0004] Traditional chip inductors primarily use ferrite as their raw material. While ferrite offers the advantage of low loss, it also has a low tolerance for saturation current and poor temperature stability. Therefore, ferrite inductors are suitable for high-frequency, low-power operating environments, but are difficult to match the application requirements of chips at high frequencies and high power. Summary of the Invention

[0005] This application provides a soft magnetic composite material, a method for preparing the soft magnetic composite material, a method for preparing an inductor, and an inductor, which can improve the application of inductors in high-frequency and high-power scenarios.

[0006] In a first aspect of this application, a soft magnetic composite material is provided, comprising a metal soft magnetic powder and a first coating layer, a second coating layer, a third coating layer, and a fourth coating layer sequentially coating the surface of the metal soft magnetic powder from the inside out; wherein, the raw material of the first coating layer comprises a first inorganic insulating material and / or a precursor of the first inorganic insulating material; the raw material of the second coating layer comprises a ferromagnetic coating material; the raw material of the third coating layer comprises an organic insulating material; and the raw material of the fourth coating layer comprises a second inorganic insulating material.

[0007] In the embodiments of this application, soft magnetic composite materials can be used as raw materials for inductors. Inductors can be manufactured by sintering the soft magnetic composite material using a sintering process. The first inorganic insulating material and / or the precursor of the first inorganic insulating material in the first coating layer of the soft magnetic composite material are the main sources of its insulation performance, effectively reducing eddy current losses. During the sintering process of the soft magnetic composite material to prepare the inductor, the ferromagnetic coating material in the second coating layer not only protects the first coating layer, reducing cracking or detachment during the sintering process, but also acts as a bonding agent for the solid pyrolysis products of the third coating layer, improving the cracking or breakage of the inductor caused by the decomposition of the organic insulating material in the third coating layer during the sintering process. The fourth coating layer further strengthens the insulation performance of the soft magnetic composite material. Inductors prepared using this soft magnetic composite material have high permeability, low magnetic loss, good high-temperature resistance, and can withstand higher saturation currents, making them more suitable for relatively high-frequency, high-power operating environments, such as AI processors.

[0008] In some embodiments, the first inorganic insulating material comprises at least one of silicon oxide, aluminum oxide, magnesium oxide, zinc oxide, iron phosphate, ferric dihydrogen phosphate, aluminum phosphate, and sodium silicate; and / or, the ferromagnetic coating material comprises at least one of nickel, nickel alloy, and ferrite; and / or, the organic insulating material comprises at least one of thermosetting resin, monomer of thermosetting resin, and oligomer of thermosetting resin; and / or, the second inorganic insulating material comprises at least one of glass powder, mica, kaolin, aluminum borosilicate, silicon carbide, silicon oxide, aluminum oxide, and magnesium oxide.

[0009] In some embodiments, the organic insulating material includes at least one of: organosilicon resin, organosilicon resin monomer, organosilicon resin oligomer, modified organosilicon resin, modified organosilicon resin monomer, and modified organosilicon resin oligomer.

[0010] In some embodiments, the soft magnetic powder includes at least one of carbonyl iron powder, iron-silicon alloy powder, iron-silicon-chromium alloy powder, iron-silicon-aluminum alloy magnetic core powder, iron-nickel alloy powder, and amorphous powder.

[0011] In some embodiments, the D of the metal soft magnetic powder 50 The value ranges from 1μm to 40μm.

[0012] In some embodiments, the raw materials for the first coating layer further include: a dispersant and a coupling agent; wherein the dispersant includes at least one of water, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, tetrahydrofuran, methylpyrrolidone, and methyl acetal; and the coupling agent includes at least one of silane coupling agents, titanate coupling agents, and mixed aluminate coupling agents.

[0013] In some embodiments, in the soft magnetic composite material: the mass of the first coating layer accounts for 0.5 wt% to 4 wt% of the mass of the soft magnetic metal powder; and / or, the mass of the second coating layer accounts for 0.1 wt% to 5 wt% of the mass of the soft magnetic metal powder; and / or, the mass of the third coating layer accounts for 1 wt% to 3.5 wt% of the mass of the soft magnetic metal powder; and / or, the mass of the fourth coating layer accounts for 0.1 wt% to 0.5 wt% of the mass of the soft magnetic metal powder.

[0014] In a second aspect of this application, a method for preparing a soft magnetic composite material is also provided, the method comprising: taking the raw material of the soft magnetic composite material described in the first aspect; and preparing the soft magnetic composite material using the raw material of the soft magnetic composite material.

[0015] In a third aspect of this application, a method for preparing an inductor is also provided, the method comprising: taking the soft magnetic composite material described in the first aspect; molding the soft magnetic composite material to obtain an inductor green blank; and sintering the inductor green blank under the protection of an inert gas to obtain an inductor.

[0016] In some embodiments, the sintering temperature is 650°C to 750°C, and the sintering time is 1.5h to 2.5h.

[0017] In a fourth aspect of this application, an inductor is also provided, the inductor being made of the soft magnetic composite material described in the first aspect.

[0018] In a fifth aspect of this application, a chip is also provided, the chip including the inductor described in the fourth aspect.

[0019] It should be understood that the description in the Summary of the Invention section is not intended to limit the key or essential features of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a soft magnetic composite material particle provided in some embodiments of this application; Figure 2 These are the annealing curves provided in the embodiments and comparative examples of this application; Figure 3 (a) in the figure is a SEM image of the soft magnetic composite material provided in Example 1; Figure 3 (b) is a SEM image of the soft magnetic composite material provided in Example 5 of this application. Detailed Implementation

[0022] The principles and spirit of this disclosure will be described below with reference to several exemplary embodiments illustrated in the accompanying drawings. It should be understood that these specific embodiments are described merely to enable those skilled in the art to better understand and implement this disclosure, and are not intended to limit the scope of this disclosure in any way. In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

[0023] As used herein, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "an embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc., may refer to different or the same objects and are used only to distinguish the objects referred to, without implying a particular spatial order, temporal order, order of importance, etc., of the objects referred to.

[0024] In a first aspect of this application, a soft magnetic composite material is provided for fabricating inductors, such as sintered inductors, i.e., inductors obtained by sintering the soft magnetic composite material. Exemplarily, Figure 1 These are schematic diagrams of the soft magnetic composite materials provided in some embodiments of this application. For example... Figure 1 As shown, the soft magnetic composite material 100 includes a metallic soft magnetic powder 10 and a first coating layer 11, a second coating layer 12, a third coating layer 13, and a fourth coating layer 14 sequentially coated on the surface of the metallic soft magnetic powder from the inside out. Specifically, the raw material of the first coating layer 11 includes a first inorganic insulating material and / or a precursor of the first inorganic insulating material; the raw material of the second coating layer 12 includes a ferromagnetic coating material; the raw material of the third coating layer 13 includes an organic insulating material; and the raw material of the fourth coating layer includes a second inorganic insulating material. The first coating layer 11, the third coating layer 13, and the fourth coating layer 14 are all insulating layers. In this embodiment, multi-layer coating of the metallic soft magnetic powder 10 can reduce the eddy current loss of the metallic soft magnetic powder 10, enabling the metallic soft magnetic material 100 to possess both high magnetic permeability and high-frequency stability.

[0025] In the embodiments of this application, the soft magnetic powder is a powdered soft magnetic material. Soft magnetic materials refer to materials whose coercivity is no greater than 1000 A / m when magnetization occurs. To improve the magnetic properties of the inductor, the soft magnetic powder can specifically be at least one of carbonyl iron powder, iron-silicon alloy powder, iron-silicon-chromium alloy powder, iron-silicon-aluminum alloy powder, iron-nickel alloy powder, and amorphous powder.

[0026] In some embodiments, to further improve the magnetic properties of the inductor, the D of the metal soft magnetic powder... 50 The range is from 1μm to 40μm; where D 50 The median diameter or median particle size is used to represent the average particle size of soft magnetic powder.

[0027] In some embodiments, to further improve the magnetic properties and high-frequency stability of the inductor, the first inorganic insulating material includes at least one of silicon oxide, aluminum oxide, iron phosphate, aluminum phosphate, and iron borate.

[0028] In some embodiments, the raw material of the first coating layer further includes a dispersant. The dispersant is used to improve the dispersibility of the metal soft magnetic powder and the raw material particles of the first coating layer (i.e., the first inorganic insulating material and / or the precursor of the first inorganic insulating material), and to reduce the surface energy of the metal soft magnetic powder and the raw material particles of the first coating layer, thereby improving the interfacial bonding ability between the first coating layer and the surface of the metal soft magnetic powder.

[0029] Specifically, in some embodiments, the dispersant may include at least one of water, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, tetrahydrofuran, methylpyrrolidone, and methyl acetal. Compared to other dispersants, the dispersant provided in this application embodiment can better improve the dispersibility of the raw material particles of the metal soft magnetic powder and the first coating layer, and can also better enhance the interfacial bonding ability between the first coating layer and the surface of the metal soft magnetic powder.

[0030] In other embodiments, the raw material of the first coating layer further includes a coupling agent. The coupling agent is used to improve the dispersibility of the metal soft magnetic powder and the raw material particles of the first coating layer, and to improve the interfacial adhesion between the metal soft magnetic powder and the first coating layer.

[0031] Specifically, in some embodiments, the coupling agent may include a silane coupling agent, a titanate coupling agent, and / or an aluminate coupling agent. For example, the titanate coupling agent may be isopropoxytriisostearatetoxytitanate, isopropyl dioleoyloxy(dioctylphosphoyloxy)titanate, or isopropoxytris(dioctylpyrophosphoyloxy)titanate; the aluminate coupling agent may include isopropoxydistearatealuminate.

[0032] In some embodiments, the silane coupling agent includes a silane coupling agent with the general formula RSiX3; wherein R is an organic functional group such as amino, mercapto, vinyl, or epoxy; and X is a hydrolyzable alkoxy group. For example, the silane coupling agent may be at least one of γ-aminopropyltriethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane. Compared to other coupling agents, the silane coupling agent provided in this embodiment can better improve the dispersibility of the raw material particles of the metal soft magnetic powder and the first coating layer, better improve the interfacial adhesion between the metal soft magnetic powder and the first coating layer, and thus improve the mechanical properties and thermal stability of the inductor.

[0033] Specifically, in some embodiments, the coupling agent in the soft magnetic composite material accounts for 0.1 wt% to 0.2 wt% of the mass of the soft magnetic metal powder. A coupling agent mass of less than 0.1 wt% or more than 0.2 wt% of the soft magnetic metal powder is detrimental to improving the overall inductance performance.

[0034] Specifically, in some embodiments, the mass of the first coating layer in the soft magnetic composite material accounts for 0.5wt% to 4wt% of the mass of the metal soft magnetic powder. If the mass of the first coating layer in the soft magnetic composite material exceeds 4wt% of the mass of the metal soft magnetic powder, it is easy to cause a decrease in the magnetic properties of the soft magnetic composite material and weaken its electromagnetic conversion capability; if the mass of the first coating layer is less than 0.5wt% of the mass of the metal soft magnetic powder, it is easy to cause a deterioration in the coating effect of the soft magnetic composite material, resulting in an overall decrease in the insulation performance of the soft magnetic composite material, and consequently, an increase in the loss of the inductor element prepared using the soft magnetic composite material.

[0035] In some embodiments, the second coating layer is a ferromagnetic coating material. On one hand, the ferromagnetic coating material protects the first coating layer during the sintering process, reducing cracking or detachment during sintering. Without the protection of the second coating layer, the first coating layer is prone to cracking or detaching from the surface of the soft magnetic powder during sintering, leading to a decrease in the insulation performance of the soft magnetic composite material after sintering. On the other hand, the ferromagnetic coating material also acts as a bonding agent for the solid sintered products of the third coating layer during the sintering process, reducing the risk of cracking or breakage of the inductor element caused by the decomposition of the organic insulating material in the third coating layer during high-temperature sintering. Furthermore, the ferromagnetic coating material can reduce eddy current losses in the soft magnetic composite material while also reducing magnetic dilution of the soft magnetic powder.

[0036] Specifically, in some embodiments, the ferromagnetic coating material can be at least one of metallic nickel, nickel alloys, and ferrite. In this embodiment, metallic nickel, nickel alloys, and ferrite have suitable hardness, which is beneficial for further enhancing the interlocking and bonding effect of the ferromagnetic coating material. Excessive or insufficient hardness of the ferromagnetic coating material may adversely affect its interlocking and bonding effect.

[0037] Specifically, in some embodiments, the mass of the second coating layer accounts for 0.1 wt% to 5 wt% of the mass of the soft magnetic powder. In this embodiment, if the mass of the second coating layer accounts for more than 5 wt% of the mass of the soft magnetic powder, it will lead to a decrease in the magnetic properties and insulation properties of the soft magnetic composite material; if the mass of the second coating layer accounts for less than 0.1 wt% of the mass of the soft magnetic powder, it will lead to a decrease in the protective effect of the second coating layer on the first coating layer, thereby making the first coating layer easily damaged during the sintering process and reducing the environmental stability of the inductor.

[0038] In some embodiments, the third coating layer is an organic insulating material. The organic insulating material includes at least one of a thermosetting resin, a monomer of a thermosetting resin, and an oligomer of a thermosetting resin. For example, the thermosetting resin may specifically be an epoxy resin. During the sintering process of the soft magnetic composite material, the organic insulating material in the third coating layer undergoes thermal decomposition to obtain solid pyrolysis products. The solid pyrolysis products may include carbon.

[0039] To further improve the overall performance of the inductor, the thermosetting resin can also be a silicone resin and / or a modified silicone resin; for example, polyurethane-modified silicone resin, polyester-modified silicone resin, epoxy-modified silicone resin, and / or phenolic-modified silicone resin. When the thermosetting resin includes silicone resin and / or modified silicone resin, the solid pyrolysis products of the third coating layer also include silicon dioxide. Silica can work with the fourth coating layer to reinforce the insulation of the soft magnetic composite material during sintering and can also prevent the growth and engulfment of sintered crystal grains.

[0040] In some embodiments, using monomers and / or oligomers of thermosetting resins as organic insulating materials is beneficial for improving the mechanical strength of the inductor. In some embodiments of this application, the degree of polymerization of the oligomers of thermosetting resins is 1 to 10 in order to further improve the overall performance of the inductor.

[0041] In some embodiments, the mass of the third coating layer accounts for 1 wt% to 3.5 wt% of the mass of the soft magnetic powder. In this embodiment, if the mass of the third coating layer accounts for more than 3.5 wt% of the mass of the soft magnetic powder, it will lead to a decrease in the magnetic permeability and saturation magnetic induction of the soft magnetic composite material; if the mass of the third coating layer accounts for less than 1 wt% of the mass of the soft magnetic powder, it will lead to a decrease in the mechanical strength of the manufactured inductor, making the inductor prone to cracking or breakage during use, thereby reducing the product yield and service life of the inductor.

[0042] In some embodiments, the fourth coating layer is a second inorganic insulating material. The fourth coating layer is used to compensate for the insulation performance of the soft magnetic composite material. In some embodiments of this application, in order to improve the compensation effect of the fourth coating layer on the insulation performance of the soft magnetic composite material, the second inorganic insulating material may specifically include at least one selected from glass powder, mica, kaolin, aluminum borosilicate (AlBSi), silicon carbide, silicon oxide, aluminum oxide, and magnesium oxide.

[0043] Specifically, in some embodiments, in order to balance the magnetic properties and insulation performance of the soft magnetic composite material, the mass of the fourth coating layer accounts for 0.1wt% to 0.5wt% of the mass of the metal soft magnetic powder.

[0044] In some embodiments, in order to improve the product appearance yield of soft magnetic composite materials, the particle size of the soft magnetic composite material particles is +300 mesh to -50 mesh.

[0045] In a second aspect of this application, a method for preparing a soft magnetic composite material is also provided. The method is used to prepare the soft magnetic composite material described in the first aspect. The method includes the following steps: taking the raw material of the soft magnetic composite material described in the first aspect, and preparing the soft magnetic composite material using the raw material of the soft magnetic composite material.

[0046] In this embodiment, the specific composition of the raw materials of the soft magnetic composite material can be referred to the description of the raw material composition of the soft magnetic composite material in the first aspect, and will not be repeated here.

[0047] In some embodiments, the raw materials of soft magnetic composite materials can be used to form the first to fourth coating layers on the surface of the metal soft magnetic powder by means of sol-gel method, chemical co-precipitation method or solvothermal method.

[0048] In some embodiments, the step of preparing soft magnetic composite materials using raw materials specifically includes: (1) The metal soft magnetic powder and the raw materials of the first coating material (e.g., the first inorganic insulating material and / or the precursor, dispersant and coupling agent of the first inorganic insulating material) are subjected to a first mixing treatment, followed by a first drying treatment, thereby forming a first coating layer on the surface of the metal soft magnetic powder to obtain a single-layer coated soft magnetic material. Specifically, the temperature of the first mixing treatment is 40℃~80℃, and the time of the first mixing treatment is 30min~240min. The temperature of the first drying treatment is 40℃~80℃, and the time of the first drying treatment is 30min~240min.

[0049] (2) The single-layer soft magnetic coating material and the raw material of the second coating layer (e.g., ferromagnetic coating material) are subjected to a second mixing treatment, and then a second drying treatment is performed to form a second coating layer on the surface of the first coating layer, thereby obtaining a double-layer coated soft magnetic material; wherein the temperature and time of the second drying treatment are the same as those of the first drying treatment.

[0050] (3) The double-layer soft magnetic coating material is mixed with organic insulating material (e.g., monomers and / or oligomers of thermosetting resin), granulated, and then subjected to a third drying treatment to form a third coating layer on the surface of the second coating layer, thereby obtaining a three-layer coated soft magnetic material; wherein the temperature of the third drying treatment is 40℃~80℃ and the time of the third drying treatment is 30min~180min.

[0051] (4) The three-layer coated soft magnetic material is mixed with the raw material of the fourth coating layer (e.g., the second inorganic insulating material) to form the fourth coating layer on the surface of the third coating layer, thereby obtaining the soft magnetic composite material.

[0052] In a third aspect of this application, a method for preparing an inductor is also provided, the method comprising: taking raw materials of the soft magnetic composite material described in the first aspect, molding the soft magnetic composite material to obtain an inductor green blank; and sintering the inductor green blank under the protection of an inert gas to obtain an inductor.

[0053] In this embodiment, the specific composition of the raw materials of the soft magnetic composite material can be referred to the description of the raw material composition of the soft magnetic composite material in the first aspect, and will not be repeated here.

[0054] In some embodiments, the soft magnetic composite material can be formed by hot pressing to obtain an inductor green blank, and then the inductor green blank is sintered under the protection of an inert gas (such as nitrogen or argon) to obtain the inductor. The sintering temperature can be 650℃~750℃, and the sintering time can be 1.5h~2.5h.

[0055] In a fourth aspect of this application, an inductor is also provided, the inductor being made from the soft magnetic composite material described in the first aspect. In this embodiment, the specific composition of the soft magnetic composite material can be referred to the description of the raw material composition of the soft magnetic composite material in the first aspect, and will not be repeated here. This inductor can be prepared using the method described in the fourth aspect of this application.

[0056] Several embodiments of this application are provided below.

[0057] The raw material compositions of the first, second, third, and fourth coating layers of the soft magnetic composite materials provided in Examples 1-12 are shown in Table 1. Table 1 shows the amount of each raw material added per 100 parts of soft magnetic metal powder. For example, in Example 1, the amount of silicon dioxide added per part of FeSiCr powder is 0.50%.

[0058] The preparation methods of the soft magnetic composite materials provided in Examples 1-12 are as follows: (1) FeSiCr powder (metal soft magnetic powder) and the raw materials of the first coating material are subjected to a first mixing treatment and then a first drying treatment to form a first coating layer (L1) on the surface of the metal soft magnetic powder, thereby obtaining a single-layer coated soft magnetic material. The mass of the first coating layer accounts for 0.5wt% of the mass of the metal soft magnetic powder.

[0059] (2) The single-layer soft magnetic coating material and the raw material of the second coating layer are subjected to a second mixing treatment, followed by a second drying treatment, thereby forming a second coating layer (L2) on the surface of the first coating layer, resulting in a double-layer coated soft magnetic material. The mass of the second coating layer accounts for 0.5 wt% of the mass of the metal soft magnetic powder.

[0060] (3) The double-layer soft magnetic coating material is mixed with organic insulating material, granulated, and then subjected to a third drying treatment to form a third coating layer (L3) on the surface of the second coating layer, thus obtaining a three-layer coated soft magnetic material. The mass of the third coating layer accounts for 3wt% of the mass of the metal soft magnetic powder.

[0061] (4) The three-layer coated soft magnetic material is mixed with the raw material of the fourth coating layer to form a fourth coating layer (L4) on the surface of the third coating layer, thereby obtaining a soft magnetic composite material. The mass of the fourth coating layer accounts for 0.1 wt% of the mass of the metal soft magnetic powder.

[0062] The difference between the soft magnetic composite materials provided in Comparative Examples 1-7 and Examples 1-12 lies in the different raw material compositions of the first to each coating layer. Furthermore, the raw material compositions of each layer in the soft magnetic composite materials corresponding to Comparative Examples 1-7 are shown in Table 2.

[0063] Table 1:

[0064] Table 2:

[0065] Please see Figure 3 ,in, Figure 3 (a) is a scanning electron microscope (SEM) image of the soft magnetic composite material provided in Comparative Example 1; Figure 3 Image (b) is a SEM image of the soft magnetic composite material provided in Example 5 of this application. By comparison... Figure 3 (a) and Figure 3 As can be seen in (b), silicon carbide and AlBSi are distributed on the surface of the soft magnetic composite material, forming a fourth coating layer.

[0066] The performance testing methods for the soft magnetic composite powders provided in each embodiment and comparative example are as follows: 2.5g of the soft magnetic composite material provided in each embodiment and comparative example was taken and pressed into a ring-shaped green preform with an outer diameter of 16.6mm and an inner diameter of 10.2mm under a pressure of 15T. The ring-shaped green preform was then placed in a tube furnace under a nitrogen atmosphere for sintering treatment (also known as annealing treatment) to obtain the magnetic rings prepared from the soft magnetic composite materials provided in each embodiment and comparative example. The temperature change curve of the annealing treatment over time is shown in the figure. Figure 2 As shown; the annealing process includes annealing at 700℃ for 2 hours. The effective magnetic permeability, magnetic loss, pressure resistance, salt spray resistance, and curing strength of the magnetic rings prepared from the soft magnetic composite materials provided in each embodiment and comparative example were characterized. The performance test results of the magnetic rings corresponding to Examples 1-12 are shown in Table 3, and the performance test results of the magnetic rings corresponding to Comparative Examples 1-7 are shown in Table 4.

[0067] Table 3:

[0068] Table 4:

[0069] Based on the experimental data in Tables 3 and 4, we can conclude that: The soft magnetic composite materials provided in this application exhibit excellent comprehensive magnetic properties, pressure resistance, and curing strength. Compared to the comparative examples, the permeability of the magnetic rings corresponding to the soft magnetic composite materials provided in Examples 1-12 is slightly reduced, but the magnetic loss performance, pressure resistance, and salt spray resistance of each example are significantly improved.

[0070] By comparing the experimental data of Examples 1-12 and Comparative Example 1, it can be seen that FeSiCr powder with only one organic coating layer (i.e., the third coating layer L3) has higher magnetic loss after sintering, and poorer pressure resistance and salt spray resistance.

[0071] Comparing the experimental data from Examples 1-12, Comparative Examples 4 and 6, it can be seen that: when the second cladding layer is metallic nickel, the blank strength of the magnetic ring is the highest; when the second cladding layer is an iron-nickel alloy, the blank strength of the magnetic ring is second; and when the second cladding layer is manganese-zinc ferrite, the blank strength of the magnetic ring is the lowest. Correspondingly, when the second cladding layer is manganese-zinc ferrite, the effective permeability of the magnetic ring is the highest; when the second cladding layer is an iron-nickel alloy, the effective permeability of the magnetic ring is second; and when the second cladding layer is metallic nickel, the effective permeability of the magnetic ring is the lowest.

[0072] Comparing the experimental data of Examples 1-12 and Comparative Examples 1-7, it can be seen that: in Examples 1-12, increasing the number of coating layers can effectively improve the rust resistance of the magnetic ring, but the effective permeability of the magnetic ring will decrease slightly; increasing the coating amount of each coating layer can also effectively improve the rust resistance of the magnetic ring, but the effective permeability of the magnetic ring will also decrease.

[0073] The experimental results above show that the inductors prepared using this soft magnetic coating powder have excellent comprehensive magnetic properties and reliability, making them more suitable for applications in high-frequency and high-current fields; for example, they can be applied to AI processors such as GPUs, TPUs, FPGAs, and ASICs.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A soft magnetic composite material, characterized by, The soft magnetic composite material comprises metallic soft magnetic powder and a first coating layer, a second coating layer, a third coating layer, and a fourth coating layer sequentially coated on the surface of the metallic soft magnetic powder from the inside out; wherein... The raw materials for the first coating layer include a first inorganic insulating material and / or a precursor of the first inorganic insulating material; The raw material for the second coating layer includes a ferromagnetic coating material; The raw material for the third coating layer includes organic insulating materials; The raw material for the fourth coating layer includes the second inorganic insulating material; The ferromagnetic coating material is used to protect the first coating layer to reduce cracking or detachment of the first coating layer during the sintering process. The ferromagnetic coating material is also used to interlock and bond the solid pyrolysis products of the third coating layer, thereby improving the cracking or breakage of the inductor caused by the decomposition of the organic insulating material of the third coating layer during the sintering process.

2. The material according to claim 1, characterized in that, The first inorganic insulating material comprises at least one of the following: silicon oxide, aluminum oxide, magnesium oxide, zinc oxide, iron phosphate, ferric dihydrogen phosphate, aluminum phosphate, and sodium silicate; and / or, The ferromagnetic coating material includes at least one of nickel, nickel alloys, and ferrite; and / or, The organic insulating material includes at least one of thermosetting resin, monomers of thermosetting resin, and oligomers of thermosetting resin; and / or, The second inorganic insulating material includes at least one of glass powder, mica, kaolin, aluminum borosilicate, silicon carbide, silicon oxide, aluminum oxide, and magnesium oxide.

3. The material of claim 1, wherein The organic insulating material includes: At least one of the following: organosilicon resin, organosilicon resin monomer, organosilicon resin oligomer, modified organosilicon resin, modified organosilicon resin monomer, and modified organosilicon resin oligomer.

4. The material of claim 1, wherein The soft magnetic powder comprises: At least one of carbonyl iron powder, iron-silicon alloy powder, iron-silicon-chromium alloy powder, iron-silicon-aluminum alloy powder, iron-nickel alloy powder, and amorphous powder.

5. The material of claim 1, wherein The metal soft magnetic powder has a D 50 value of 1 μm to 40 μm.

6. The material of claim 1, wherein The raw materials for the first coating layer also include: dispersant and coupling agent; The dispersant includes at least one of water, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, tetrahydrofuran, methylpyrrolidone, and methyl acetal. The coupling agent includes at least one of silane coupling agents, titanate coupling agents, and / or aluminate coupling agents.

7. The material according to any one of claims 1-6, characterized in that, In the soft magnetic composite material: The first coating layer comprises 0.5 wt% to 4 wt% of the mass of the soft magnetic powder; and / or, The second coating layer comprises 0.1 wt% to 5 wt% of the mass of the soft magnetic powder; and / or, The third coating layer comprises 1 wt% to 3.5 wt% of the mass of the soft magnetic powder; and / or, The mass of the fourth coating layer accounts for 0.1 wt% to 0.5 wt% of the mass of the metal soft magnetic powder.

8. A method for preparing a soft magnetic composite material, characterized in that, The method includes: The raw material of the soft magnetic composite material according to any one of claims 1-7; The soft magnetic composite material is prepared using the raw materials of the soft magnetic composite material.

9. A method for preparing an inductor, characterized in that, The method includes: The soft magnetic composite material described in any one of claims 1-7; The soft magnetic composite material is molded to obtain an inductor green blank; The inductor green stock is sintered under the protection of an inert gas to obtain an inductor.

10. The method according to claim 9, characterized in that, The sintering temperature is 650℃~750℃, and the sintering time is 1.5h~2.5h.

11. An inductor, characterized in that, The inductor is made of the soft magnetic composite material described in any one of claims 1-7.

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