Soft magnetic composite material, preparation method of soft magnetic composite material, preparation method of inductor and inductor

Abstract

The embodiment of the invention 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 soft magnetic composite material is sintered by using a sintering process to prepare the inductor. The first coating layer of the soft magnetic composite material is the main source of the insulation performance of the soft magnetic composite material, and the eddy current loss of the soft magnetic composite material can be effectively reduced. In the process of sintering the soft magnetic composite material to prepare the inductor, the ferromagnetic coating material of the second coating layer can play a role in protecting the first coating layer, so that the phenomenon that the first coating layer cracks or falls off in the sintering process is reduced; in addition, the solid pyrolysis product of the third coating layer can be engaged and bonded, and the condition that the organic insulating material of the third coating layer is pyrolyzed in the sintering process to cause the cracking or fracture of the inductor is improved. And the fourth coating layer is used for further reinforcing the insulating property of the soft magnetic composite material.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of inductor components, and in particular to a soft magnetic composite material, a method for preparing a soft magnetic composite material, a method for preparing an inductor, and an inductor. Background Art

[0002] Chip inductor is a special form of one-piece molded inductor. It is the core component of the chip power supply module. It plays the role of supplying power to the front end of the chip to maintain the normal operation of various chips in the motherboard and graphics card.

[0003] With the continuous miniaturization of chips, the voltage of chips is getting lower and lower. It is necessary to increase the current of the chip to maintain the high power demand of the chip, which puts higher requirements 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 losses, it also suffers from low saturation current tolerance and poor temperature stability. Consequently, ferrite inductors are suited for high-frequency, low-power environments and struggle to match the high-frequency, high-power requirements of chip applications. Summary of the Invention

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

[0006] In the first aspect of the present application, a soft magnetic composite material is provided, which includes a metal 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 metal soft magnetic powder from the inside to the outside; wherein the raw material of the first coating layer includes a first inorganic insulating material and / or a precursor of the first inorganic insulating material; the raw material of the second coating layer includes a ferromagnetic coating material; the raw material of the third coating layer includes an organic insulating material; and the raw material of the fourth coating layer includes a second inorganic insulating material.

[0007] In an embodiment of the present application, a soft magnetic composite material can be used as a raw material for an inductor, and an inductor can be obtained 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 of the first coating layer of the soft magnetic composite material are the main sources of the insulating properties 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 the soft magnetic composite material to prepare an inductor, the ferromagnetic coating material of the second coating layer can not only protect the first coating layer to reduce the phenomenon of cracking or falling off of the first coating layer during the sintering process, but also play a role in meshing and bonding the solid pyrolysis product 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. The fourth coating layer is used to further strengthen the insulating properties of the soft magnetic composite material. The inductor prepared using the soft magnetic composite material has high magnetic permeability, low magnetic loss, good high temperature resistance, and can withstand a higher saturation current, making it more suitable for relatively high frequency and high power working environments, such as AI processors.

[0008] In some embodiments, the first inorganic insulating material includes: at least one of silicon oxide, aluminum oxide, magnesium oxide, zinc oxide, iron phosphate, ferrous phosphate, aluminum phosphate and sodium silicate; and / or, the ferromagnetic coating material includes: at least one of nickel, nickel alloy and ferrite; and / or, the organic insulating material includes: at least one of thermosetting resin, monomer of thermosetting resin and oligomer 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.

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

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

[0011] In some embodiments, the D 50 The value is 1μm~40μm.

[0012] In some embodiments, the raw materials of the first coating layer also 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, methyl pyrrolidone and methylal; the coupling agent includes at least one of a silane coupling agent, a titanate coupling agent and a mixed aluminate coupling agent.

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

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

[0015] In the third aspect of the present application, a method for preparing an inductor is also provided, the method comprising: taking the soft magnetic composite material described in the first aspect; shaping the soft magnetic composite material to obtain an inductor embryo; and sintering the inductor embryo 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 1.5 h to 2.5 h.

[0017] In a fourth aspect of the present application, an inductor is further provided, wherein the raw material of the inductor includes the soft magnetic composite material described in the first aspect.

[0018] In a fifth aspect of the present application, a chip is further provided, which includes the inductor described in the fourth aspect.

[0019] It should be understood that the contents described in the Summary of the Invention are not intended to define the key or important features of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0021] Figure 1 is a schematic structural diagram of a soft magnetic composite material particle provided in some embodiments of the present application; Figure 2 is the annealing curve provided in the examples and comparative examples of the present application; Figure 3 (a) is a SEM image of the soft magnetic composite material provided in Comparative Example 1; Figure 3 (b) is a SEM image of the soft magnetic composite material provided in Example 5 of the present application. DETAILED DESCRIPTION

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

[0023] As used herein, the term "including" and similar terms should be understood as open inclusion, i.e., "including but not limited to." The term "based on" should be understood as "based at least in part on." The term "one 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 only used to distinguish the objects referred to, and do not imply a specific spatial order, temporal order, order of importance, etc. of the objects referred to.

[0024] In a first aspect of the present application, a soft magnetic composite material is provided, which is used to prepare an inductor, such as a sintered inductor, that is, an inductor prepared by sintering the soft magnetic composite material. For example, Figure 1 Schematic diagram of the structure of the soft magnetic composite material provided by some embodiments of the present application. Figure 1 As shown, the soft magnetic composite material 100 includes a metal 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 metal 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, the multi-layer coating treatment of the metal soft magnetic powder 10 can reduce the eddy current loss of the metal soft magnetic powder 10, so that the metal soft magnetic material 100 has both high magnetic permeability and high-frequency stability.

[0025] In the embodiments of the present application, the metal soft magnetic powder is a powdered metal soft magnetic material. Soft magnetic materials refer to materials with a coercive force of no greater than 1000 A / m when magnetized. To improve the magnetic properties of the inductor, the metal soft magnetic powder can specifically be at least one of carbonyl iron powder, iron-silicon alloy powder, iron-silicon-chromium alloy powder, sendust alloy powder, iron-nickel alloy powder, and amorphous powder.

[0026] In some embodiments, in order to further improve the magnetic properties of the inductor, the D 50 1μm~40μm; among them, D 50 It is the median diameter or median particle size, used to indicate the average particle size of metal soft magnetic powder.

[0027] In some embodiments, in order 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 materials for the first coating layer further include 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 a 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, methyl pyrrolidone, and methylal. Compared to other dispersants, the dispersant provided in the embodiments of the present application 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, which 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 interface bonding performance 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 isopropoxy triisostearyl titanate, isopropyl dioleyl (dioctyl phosphate) titanate, or isopropoxy tris (dioctyl pyrophosphate) titanate; the aluminate coupling agent may include isopropoxy distearate aluminate.

[0032] In some embodiments, the silane coupling agent includes a silane coupling agent of the general formula RSiX3; wherein R is an organic functional group such as an amino group, a thiol group, a vinyl group, or an epoxy group; and X is a hydrolyzable alkoxy group. For example, the silane coupling agent can be at least one of γ-aminopropyltriethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane. Compared with other coupling agents, the silane coupling agent provided in this embodiment can better improve the dispersibility of the metal soft magnetic powder and the raw material particles of the first coating layer, better improve the interfacial bonding performance 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 mass of the coupling agent in the soft magnetic composite material accounts for 0.1 wt% to 0.2 wt% of the mass of the metal soft magnetic powder. A mass of the coupling agent accounting for less than 0.1 wt% of the mass of the metal soft magnetic powder, or a mass of the coupling agent accounting for more than 0.2 wt% of the mass of the metal soft magnetic powder, is not conducive to improving the overall inductance performance.

[0034] Specifically, in some embodiments, in the soft magnetic composite material, the mass of the first coating layer 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, the magnetic properties of the soft magnetic composite material may be reduced, thereby weakening the electromagnetic conversion capability of the soft magnetic composite material. If the mass of the first coating layer is less than 0.5wt% of the mass of the metal soft magnetic powder, the coating effect of the soft magnetic composite material may be deteriorated, resulting in a decrease in the overall insulation performance of the soft magnetic composite material, thereby increasing 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 the one hand, the ferromagnetic coating material is used to protect the first coating layer during the sintering process, reducing the cracking or falling off of the first coating layer during the sintering process; without the protection of the second coating layer, the first coating layer is prone to cracking or falling off from the surface of the metal soft magnetic powder during the sintering process, resulting in a decrease in the insulation performance of the soft magnetic composite material after the sintering process; on the other hand, the ferromagnetic coating material also plays a role in meshing and bonding the solid sintered product of the third coating layer during the sintering process, reducing the cracking or breakage of the inductor component caused by the decomposition of the organic insulating material in the third coating layer during the high-temperature sintering process. In addition, the ferromagnetic coating material can also reduce the eddy current loss of the soft magnetic composite material while reducing the magnetic dilution of the metal soft magnetic powder.

[0036] Specifically, in some embodiments, the ferromagnetic coating material can be at least one of nickel, a nickel alloy, and ferrite. In this embodiment, the nickel, nickel alloy, and ferrite have an appropriate hardness to further enhance the meshing and bonding properties of the ferromagnetic coating material. Excessively high or low hardness of the ferromagnetic coating material can adversely affect its meshing and bonding properties.

[0037] Specifically, in some embodiments, the mass of the second coating layer accounts for 0.1wt% to 5wt% of the mass of the soft magnetic powder. In this embodiment, if the mass of the second coating layer accounts for more than 5wt% of the mass of the soft magnetic powder, the magnetic properties and insulation properties of the soft magnetic composite material will be reduced. If the mass of the second coating layer accounts for less than 0.1wt% of the mass of the soft magnetic powder, the protective effect of the second coating layer on the first coating layer will be weakened, and the first coating layer will be easily damaged during the sintering process, 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 be an epoxy resin. During the sintering process of the soft magnetic composite material, the organic insulating material in the third coating layer is thermally decomposed to produce a solid pyrolysis product. The solid pyrolysis product may include carbon.

[0039] To further enhance the overall performance of the inductor, the thermosetting resin can also be a silicone resin and / or a modified silicone resin; for example, a polyurethane-modified silicone resin, a polyester-modified silicone resin, an epoxy-modified silicone resin, and / or a phenolic-modified silicone resin. When the thermosetting resin comprises a silicone resin and / or a modified silicone resin, the solid pyrolysis product of the third coating layer can also include silicon dioxide. Silicon dioxide, together with the fourth coating layer, can reinforce the dielectric breakdown of the soft magnetic composite material during sintering and prevent the sintered grains from coalescing and growing.

[0040] In some embodiments, using thermosetting resin monomers and / or oligomers as the organic insulating material can improve the mechanical strength of the inductor. In certain embodiments of the present application, to further enhance the overall performance of the inductor, the degree of polymerization of the thermosetting resin oligomer is 1 to 10.

[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, the magnetic permeability and saturation magnetic induction intensity of the soft magnetic composite material will be reduced. If the mass of the third coating layer accounts for less than 1 wt% of the mass of the soft magnetic powder, the mechanical strength of the resulting inductor will be reduced, making the inductor more susceptible to cracking or breaking during use, thereby reducing the product yield and service life of the inductor.

[0042] In some embodiments, the fourth coating layer comprises a second inorganic insulating material. The fourth coating layer is used to compensate for the insulating properties of the soft magnetic composite material. In certain embodiments of the present application, to enhance the fourth coating layer's ability to compensate for the insulating properties of the soft magnetic composite material, the second inorganic insulating material may include at least one of glass frit, mica, kaolin, aluminum borosilicate (AlBSi), silicon carbide, silicon oxide, aluminum oxide, and magnesium oxide.

[0043] Specifically, in some embodiments, in order to take into account both the magnetic properties and the insulation properties of the soft magnetic composite material, 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.

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

[0045] In the second aspect of the present 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 materials of the soft magnetic composite material described in the first aspect, and using the raw materials of the soft magnetic composite material to prepare a soft magnetic composite material.

[0046] In this embodiment, the raw material composition of the soft magnetic composite material can be specifically 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 the soft magnetic composite material can be used to form the first to fourth coating layers on the surface of the metal soft magnetic powder by a sol-gel method, a chemical co-precipitation method or a solvothermal method.

[0048] In some embodiments, the steps of preparing the soft magnetic composite material using raw materials of the soft magnetic composite material specifically include: (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 of the first inorganic insulating material, the dispersant, and the coupling agent) are subjected to a first mixing treatment, and then subjected to 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°C to 80°C, and the time of the first mixing treatment is 30 minutes to 240 minutes. The temperature of the first drying treatment is 40°C to 80°C, and the time of the first drying treatment is 30 minutes to 240 minutes.

[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 subjected to a second drying treatment, thereby forming a second coating layer on the surface of the first coating layer to obtain a double-layer coated soft magnetic material; wherein the temperature and time of the second drying treatment are the same as the temperature and time of the first drying treatment.

[0050] (3) The double-layer soft magnetic coating material is mixed with an organic insulating material (e.g., a monomer and / or oligomer of a thermosetting resin), granulated, and then subjected to a third drying treatment, thereby forming a third coating layer on the surface of the second coating layer to obtain a three-layer coated soft magnetic material; wherein the temperature of the third drying treatment is 40°C to 80°C, and the time of the third drying treatment is 30 minutes to 180 minutes.

[0051] (4) The three layers of coated soft magnetic material are mixed with the raw material of the fourth coating layer (eg, the second inorganic insulating material), thereby forming a fourth coating layer on the surface of the third coating layer to obtain a soft magnetic composite material.

[0052] In the third aspect of the present application, a method for preparing an inductor is also provided, which comprises: taking the raw material of the soft magnetic composite material described in the first aspect, shaping the soft magnetic composite material to obtain an inductor embryo; and sintering the inductor embryo under the protection of an inert gas to obtain an inductor.

[0053] In this embodiment, the raw material composition of the soft magnetic composite material can be specifically 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 through a hot pressing process to obtain an inductor green body. The green body is then sintered under an inert gas (such as nitrogen or argon) to obtain the inductor. The sintering temperature can be 650°C to 750°C, and the sintering time can be 1.5 hours to 2.5 hours.

[0055] In a fourth aspect of the present application, an inductor is further provided, wherein the raw materials of the inductor include the soft magnetic composite material described in the first aspect. In this embodiment, the raw material composition of the soft magnetic composite material can be specifically referred to the description of the raw material composition of the soft magnetic composite material in the first aspect and will not be further described here. The inductor can be prepared using the method described in the fourth aspect of the present application.

[0056] Several embodiments of the present 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 amounts of each raw material added per 100 parts of metallic soft magnetic powder. For example, in Example 1, the amount of silicon oxide 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 raw materials of a first coating material are subjected to a first mixing process and then to a first drying process, thereby forming a first coating layer (L1) on the surface of the metal soft magnetic powder to obtain 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 process, and then subjected to a second drying process, thereby forming a second coating layer (L2) on the surface of the first coating layer to obtain a double-layer coated soft magnetic material. The mass of the second coating layer accounts for 0.5wt% of the mass of the metal soft magnetic powder.

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

[0061] (4) The three layers of soft magnetic material are 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 is that the raw material compositions of the first to each coating layer are different. 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] See also 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 (b) is the SEM image of the soft magnetic composite material provided in Example 5 of the present application. Figure 3 (a) and Figure 3 As can be seen from (b), silicon carbide and AlBSi are distributed on the surface of the soft magnetic composite material to form the fourth coating layer.

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

[0067] Table 3:

[0068] Table 4:

[0069] According to the experimental data in Table 3 and Table 4, we can know that: The soft magnetic composite materials provided in the examples of this application exhibit excellent comprehensive magnetic properties, pressure resistance, and green strength. Compared to the comparative examples, the magnetic permeability of the magnetic rings corresponding to the soft magnetic composite materials provided in Examples 1-12 decreased slightly, but the magnetic loss performance, pressure resistance, and salt spray resistance of each example were significantly improved.

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

[0071] By comparing the experimental data of Examples 1-12, Comparative Examples 4, and 6, it can be seen that when the second coating layer is nickel, the magnetic ring has the highest green strength; when the second coating layer is iron-nickel alloy, the magnetic ring has the second lowest green strength; when the second coating layer is manganese-zinc ferrite, the magnetic ring has the lowest green strength. Correspondingly, when the second coating layer is manganese-zinc ferrite, the magnetic ring has the highest effective magnetic permeability; when the second coating layer is iron-nickel alloy, the magnetic ring has the second lowest effective magnetic permeability; when the second coating layer is nickel, the magnetic ring has the lowest effective magnetic permeability.

[0072] By comparing the experimental data of Examples 1 to 12 and Comparative Examples 1 to 7, it can be seen that Examples 1 to 12 can effectively improve the rust resistance of the magnetic ring by increasing the number of coating layers, but the effective magnetic permeability of the magnetic ring will be slightly reduced; by increasing the coating amount of each coating layer, the rust resistance of the magnetic ring can also be effectively improved, but the effective magnetic permeability of the magnetic ring will also be reduced.

[0073] From the above experimental results, it can be seen that the inductor prepared using the soft magnetic coated powder has excellent comprehensive magnetic properties and reliability, and is more suitable for application in high frequency and high current fields; for example, it can be applied to AI processors such as GPU, TPU, FPGA and ASIC.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above. For the sake of simplicity, they are not provided in detail. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A soft magnetic composite material, characterized in that: The soft magnetic composite material comprises a metal 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 metal soft magnetic powder from the inside to the outside; wherein, The raw material of the first coating layer includes a first inorganic insulating material and / or a precursor of the first inorganic insulating material; The raw material of the second coating layer includes a ferromagnetic coating material; The raw material of the third coating layer includes organic insulating material; The raw material of the fourth coating layer includes a second inorganic insulating material.

2. The material according to claim 1, characterized in that The first inorganic insulating material includes: at least one of silicon oxide, aluminum oxide, magnesium oxide, zinc oxide, iron phosphate, ferrous dihydrogen phosphate, aluminum phosphate and sodium silicate; and / or, The ferromagnetic coating material includes: at least one of nickel, nickel alloy and ferrite; and / or, 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; 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 according to claim 1, characterized in that The organic insulating material includes: At least one of a silicone resin, a monomer of a silicone resin, an oligomer of a silicone resin, a modified silicone resin, a monomer of a modified silicone resin, and an oligomer of a modified silicone resin.

4. The material according to claim 1, characterized in that The metal soft magnetic powder comprises: At least one of carbonyl iron powder, iron silicon alloy powder, iron silicon chromium alloy powder, sendust magnetic core powder, iron nickel alloy powder and amorphous powder.

5. The material according to claim 1, characterized in that The D of the metallic soft magnetic powder 50 The value is 1μm~40μm.

6. The material according to claim 1, characterized in that The raw materials of the first coating layer also include: a dispersant and a coupling agent; Wherein, the dispersant comprises at least one of water, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, tetrahydrofuran, methylpyrrolidone and methylal; The coupling agent includes at least one of a silane coupling agent, a titanate coupling agent and a mixed aluminate coupling agent.

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

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

9. A method for preparing an inductor, characterized in that: The method comprises: Take the soft magnetic composite material according to any one of claims 1 to 7; shaping the soft magnetic composite material to obtain an inductor embryo; Under the protection of inert gas, the inductor green body is sintered to obtain the inductor.

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

11. An inductor, characterized in that: The raw material of the inductor includes the soft magnetic composite material according to any one of claims 1 to 7.

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