Impregnation solution and use thereof, method for producing a magnetic powder core and use thereof

Abstract

The application relates to the material field and discloses an impregnation liquid and application thereof, a preparation method of a magnetic powder core and application thereof. The impregnation liquid comprises ferrite powder, epoxy resin, a curing agent, a dispersing agent and a diluent; the average particle size of the ferrite powder is 10-80 nm; the content of the ferrite powder is 5-50 wt% based on the total weight of the impregnation liquid, the content of the epoxy resin is 33-62.7 wt%, the content of the curing agent is 8-15.2 wt%, the content of the dispersing agent is 1-1.9 wt%, and the content of the diluent is 8-15.2 wt%. The prepared impregnation liquid is applied in the preparation of a magnetic powder core and / or a magnetic device. The preparation method of the magnetic powder core comprises the following steps: after the magnetic powder core is soaked in the impregnation liquid, solidification treatment is carried out. The prepared magnetic powder core is applied in an inductor and / or a transformer. The impregnation liquid provided by the application can improve the strength and magnetic permeability of the magnetic powder core.

Description

Impregnating solutions and their applications; preparation methods and applications of magnetic powder cores. Technical Field

[0001] This invention relates to the field of materials, and discloses an impregnation solution and its application, as well as a method for preparing magnetic powder cores and their applications. Background Technology

[0002] Magnetic devices and magnetic powder cores made of soft magnetic composite materials are mainly used as inductors in high-power circuits. With the miniaturization of devices, soft magnetic composite materials have gradually developed due to their high magnetic density. To reduce eddy current losses within the magnetic powder core, soft magnetic composite materials typically refer to a uniform mixture of soft magnetic alloy powder and an insulating agent. The insulating agent usually uses epoxy resin, silicone resin, or phenolic resin, which have adhesive properties. Magnetic powder cores and devices are formed by pressing soft magnetic composite materials. However, the pressing process introduces internal stress, severely reducing the magnetic permeability. Therefore, industry professionals anneal the formed magnetic powder core blank, typically at around 700 degrees Celsius, to relieve stress. However, common insulating agents (adhesives) can only withstand temperatures around 500 degrees Celsius. At higher temperatures, the organic matter decomposes and is expelled, resulting in numerous pores within the magnetic powder core. For devices requiring higher mechanical strength, technicians generally increase the amount of adhesive to improve the strength of the magnetic powder core and device. Adhesives are non-magnetic materials, and adding too much will reduce the magnetic density, which will not only reduce the permeability but also increase the power loss.

[0003] CN109545537A discloses a magnetic powder core and its preparation method. Through multi-element coating, the insulating coating layer of the magnetic powder core is made more stable, but its magnetic permeability decreases with the increase of the amount of adhesive.

[0004] CN112489918A discloses an alloy magnetic powder core, its preparation method and application. A special coating compensation liquid is used to repair the coating damage caused by molding and sintering, thereby improving the magnetic core performance and corrosion resistance. However, since the pores inside the magnetic powder core are filled with non-magnetic compensation liquid, the overall magnetic density is reduced, resulting in a decrease in magnetic permeability. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of reduced magnetic permeability caused by binders in the preparation of magnetic powder cores in the prior art, and to provide an impregnation liquid and its application, as well as a method for preparing magnetic powder cores and its application. This impregnation liquid has the advantages of improving strength and magnetic permeability.

[0006] To achieve the above objectives, the first aspect of the present invention provides an impregnation liquid, characterized in that the impregnation liquid comprises ferrite powder, epoxy resin, curing agent, dispersant and diluent; the average particle size of the ferrite powder is 10-80 nm;

[0007] Based on the total weight of the impregnating liquid, the content of the ferrite powder is 5-50 wt%, the content of the epoxy resin is 33-62.7 wt%, the content of the curing agent is 8-15.2 wt%, the content of the dispersant is 1-1.9 wt%, and the content of the diluent is 8-15.2 wt%.

[0008] A second aspect of the present invention provides the application of the above-mentioned impregnation liquid in the preparation of magnetic powder cores and / or magnetic devices.

[0009] A third aspect of the present invention provides a method for preparing a magnetic powder core, characterized in that the method includes: immersing the magnetic powder core in an impregnation liquid and then performing a curing treatment to obtain the magnetic powder core; wherein the impregnation liquid is the aforementioned impregnation liquid.

[0010] The fourth aspect of the present invention provides a magnetic powder core prepared by the above-described preparation method.

[0011] The fifth aspect of the present invention provides the application of the above-described magnetic powder core in inductors and / or transformers.

[0012] Through the above technical solution, the present invention has the following beneficial effects:

[0013] The impregnation liquid of the present invention includes ferrite powder, epoxy resin, curing agent, dispersant and diluent, which reduces the content of insulating resin in the glue, avoids the use of full glue in the preparation of magnetic powder core, avoids the large-scale decomposition and discharge of organic matter when the temperature is too high, and avoids the formation of a large number of pores inside the magnetic powder core, thereby improving the strength of the magnetic powder core, increasing the magnetic density of the magnetic powder core, and thus improving the magnetic permeability. Detailed Implementation

[0014] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0015] The first aspect of the present invention provides an impregnation liquid, characterized in that the impregnation liquid comprises ferrite powder, epoxy resin, curing agent, dispersant and diluent; the average particle size of the ferrite powder is 10-80 nm;

[0016] Based on the total weight of the impregnating liquid, the content of the ferrite powder is 5-50 wt%, the content of the epoxy resin is 33-62.7 wt%, the content of the curing agent is 8-15.2 wt%, the content of the dispersant is 1-1.9 wt%, and the content of the diluent is 8-15.2 wt%.

[0017] In this invention, when the amount of each component in the impregnation liquid meets the above-mentioned range, when it is used to prepare magnetic powder cores and / or magnetic devices, the content of insulating resin is reduced due to the addition of ferrite powder, and the impregnation liquid can penetrate into the interior of the magnetic powder cores and / or magnetic devices, filling the pores, thereby improving their strength and magnetic permeability.

[0018] In this invention, when the average particle size of the ferrite powder is 10-80 nm, the ferrite powder penetrates into the interior of the magnetic powder core and / or magnetic device, filling the pores, thereby improving its strength and magnetic permeability.

[0019] Furthermore, based on the total weight of the impregnating liquid, the content of the ferrite powder is 10-40 wt%, the content of the epoxy resin is 40-59.4 wt%, the content of the curing agent is 10-14.5 wt%, the content of the dispersant is 9-14.5 wt%, and the content of the diluent is 1-1.6 wt%.

[0020] Furthermore, the average particle size of the ferrite powder is 10-60 nm.

[0021] In this invention, the type of ferrite powder is not particularly limited, for example including manganese zinc ferrite powder (Mn 0.5 Zn 0.5 Fe2O4), nickel-zinc ferrite powder (Ni 0.5 Zn 0.5 Fe2O4) and nickel-copper-zinc ferrite powder (Ni 0.4 Zn 0.4 Cu 0.2 At least one of Fe2O4.

[0022] According to the present invention, the epoxy resin is selected from epoxy resin E44 and / or epoxy resin E51.

[0023] According to the present invention, the curing agent is selected from at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride and methylnadic anhydride.

[0024] According to the present invention, the dispersant is selected from at least one of stearamide, vinyl bis-stearamide and oleic acid.

[0025] According to the present invention, the diluent is selected from at least one of ethanol, toluene, acetone and xylene.

[0026] Furthermore, the diluent is selected from at least two of ethanol, toluene, acetone, and xylene. Specifically, there are no particular requirements for the ratio between two or more diluents, as long as the total amount of diluent used meets the requirements of this invention.

[0027] A second aspect of the present invention provides the application of the above-mentioned impregnation liquid in the preparation of magnetic powder cores and / or magnetic devices.

[0028] A third aspect of the present invention provides a method for preparing a magnetic powder core, characterized in that the method comprises:

[0029] The magnetic powder core is obtained by immersing it in an impregnation solution and then performing a curing process.

[0030] The impregnating solution is the above-mentioned impregnating solution;

[0031] The soaking time is 20-60 minutes.

[0032] In this invention, the impregnation of magnetic powder cores with the impregnation solution of this invention has the effect of allowing the impregnation solution to penetrate into the magnetic powder core and / or magnetic device, filling the pores, thereby improving its strength and magnetic permeability. Limiting the soaking time to 20-60 minutes allows the impregnation solution to fully penetrate into the magnetic powder core and / or magnetic device, ensuring the effect of filling the pores.

[0033] In this invention, there is no particular limitation on the shape of the magnetic powder core; it can be a magnetic powder core of a conventional shape in the art, such as at least one of toroidal, E-type, EQ-type, and U-type. There is no particular limitation on the size of the magnetic powder core; it can be a magnetic powder core of a conventional size in the art. For example, for a toroidal magnetic powder core, the dimensions are an outer diameter of 15-20 mm, an inner diameter of 9-13 mm, and a height of 6-3 mm.

[0034] According to the present invention, the immersion is carried out under vacuum conditions.

[0035] In this invention, immersion is performed under vacuum conditions to expel the gas inside the magnetic powder core and / or magnetic device, allowing the impregnating liquid to better penetrate the interior of the magnetic powder core and / or magnetic device, filling the pores and thereby improving its strength and magnetic permeability.

[0036] Furthermore, the absolute pressure of the vacuum condition is 10-100 Pa, preferably 50-80 Pa.

[0037] Furthermore, the soaking time is 20-60 minutes, preferably 30-60 minutes.

[0038] According to the present invention, the curing conditions include: a curing time of 1-3 hours and a curing temperature of 200-250°C.

[0039] Furthermore, the curing conditions include: a curing time of 2-3 hours and a curing temperature of 220-250°C.

[0040] The fourth aspect of the present invention provides a magnetic powder core prepared by the above-described preparation method.

[0041] The fifth aspect of the present invention provides the application of the above-described magnetic powder core in inductors and / or transformers.

[0042] The present invention will be described in detail below through embodiments. In the following embodiments,

[0043] The tensile strength at break of the magnetic powder core was measured using a tensile strength tester.

[0044] The permeability of the magnetic powder core was measured using a WK3260B-LCR impedance analyzer.

[0045] The magnetic powder core is a toroidal magnetic powder core with an outer diameter of 20 mm, an inner diameter of 13 mm, and a height of 6 mm.

[0046] All raw materials used in the examples and comparative examples are commercially available products.

[0047] Example 1

[0048] Under vacuum conditions, the magnetic powder core is immersed in an impregnation solution and then cured to obtain the magnetic powder core.

[0049] The impregnation solution includes 30 wt% Mn 0.5 Zn 0.5 A magnetic powder core A1 was prepared by mixing Fe2O4, 47wt% epoxy resin E44, 11wt% methylhexahydrophthalic anhydride, 1.3wt% oleic acid, and 10.7wt% ethanol and toluene under vacuum conditions of 50 Pa absolute pressure, immersion time of 50 min, curing temperature of 230℃, and curing time of 2.5 h. The core has the following dimensions: outer diameter 20 mm, inner diameter 13 mm, and height 6.0 mm.

[0050] Examples 2-7

[0051] Magnetic powder cores were prepared according to the method of Example 1, except that the types and amounts of raw materials in the impregnation solution were different from those in Example 1, as shown in Table 1; the absolute pressure of the vacuum conditions, the soaking time, and the curing conditions were also different from those in Example 1, as shown in Table 1. Magnetic powder cores A2-A7 were prepared respectively.

[0052] Comparative Example 1

[0053] Magnetic powder cores were prepared according to the method of Example 1, except that the types and amounts of raw materials in the impregnation solution were different from those in Example 1, as shown in Table 1; the absolute pressure of the vacuum conditions, the immersion time, and the curing conditions were also different from those in Example 1, as shown in Table 1. Magnetic powder cores D1-D4 were prepared respectively.

[0054] The permeability and tensile strength of the magnetic powder cores prepared in the examples and comparative examples were tested, and the results are shown in Table 2.

[0055] Table 1

[0056]

[0057] Table 1 (continued)

[0058]

[0059]

[0060] Table 1 (continued)

[0061]

[0062] Table 2

[0063]

[0064]

[0065] Table 2 (continued)

[0066] Performance Examples 4, 5, 6, 7 Pre-impregnation breaking tensile force / N 160 160 160 160 Post-impregnation breaking tensile force / N 193.5 200.6 184.6 173.4 Rate of change / % 2125 158 Pre-impregnation permeability 70 70 70 70 Post-impregnation permeability 70.4 174.1 474.9 770.90 Rate of change / % 0.6 67.1 1.3 surface

[0067] Table 2 (continued)

[0068] Performance Comparison Example 1 Comparison Example 2 Comparison Example 3 Comparison Example 4 Tensile Strength at Break Before Impregnation / N 160 160 160 160 Tensile Strength at Break After Impregnation / N 185.2 161.2 189.2 165.2 Rate of Change / % 161 183 Permeability Before Impregnation 70 70 70 70 Permeability After Impregnation 68.41 69.75 68.65 69.45 Rate of Change / % -2.2 -0.4 -2.0 -1.0 surface

[0069] As can be seen from the results in Tables 1 and 2, compared with the comparative example, the formulation of the present invention improves both the strength and permeability of the magnetic powder core.

[0070] The impregnation solution of the present invention contains ferrite powder that penetrates into the interior of the magnetic powder core to fill the pores, thereby increasing the strength of the magnetic powder core, increasing the magnetic density of the magnetic powder core, and thus increasing the magnetic permeability.

[0071] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An impregnation solution, characterized in that, The impregnation solution comprises ferrite powder, epoxy resin, curing agent, dispersant, and diluent; based on the total weight of the impregnation solution, the content of the ferrite powder is 5-50 wt%, the content of the epoxy resin is 33-62.7 wt%, the content of the curing agent is 8-15.2 wt%, the content of the dispersant is 1-1.9 wt%, and the content of the diluent is 8-15.2 wt%; the average particle size of the ferrite powder is 10-60 nm.

2. The impregnation solution according to claim 1, characterized in that, Based on the total weight of the impregnating liquid, the content of the ferrite powder is 10-40 wt%, the content of the epoxy resin is 40-59.4 wt%, the content of the curing agent is 10-14.5 wt%, the content of the dispersant is 9-14.5 wt%, and the content of the diluent is 1-1.6 wt%.

3. The impregnation solution according to claim 1 or 2, characterized in that, The ferrite powder is selected from at least one of manganese-zinc ferrite powder, nickel-zinc ferrite powder, and nickel-copper-zinc ferrite powder.

4. The impregnation solution according to claim 1, characterized in that, The epoxy resin is selected from epoxy resin E44 and / or epoxy resin E51; the curing agent is selected from at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride and methylnadic anhydride; the dispersant is selected from at least one of stearamide, vinyl bis-stearamide and oleic acid; and the diluent is selected from at least one of ethanol, toluene, acetone and xylene.

5. The application of the impregnation solution according to claim 1 in the preparation of magnetic powder cores and / or magnetic devices.

6. A method for preparing a magnetic powder core, characterized in that, The method includes: immersing the magnetic powder core in an impregnation solution and then performing a curing treatment to obtain the magnetic powder core; the impregnation solution is the impregnation solution according to any one of claims 1-4; the immersion time is 20-60 min.

7. The preparation method according to claim 6, wherein, The immersion is carried out under vacuum conditions; the absolute pressure of the vacuum conditions is 10-100 Pa; and the immersion time is 30-60 min.

8. The preparation method according to claim 7, characterized in that, The absolute pressure under the vacuum condition is 50-80 Pa.

9. The preparation method according to claim 6, characterized in that, The curing conditions include: a curing time of 1-3 hours and a curing temperature of 200-250°C.

10. The preparation method according to claim 6, characterized in that, The curing conditions include: a curing time of 2-3 hours and a curing temperature of 220-250℃.

11. A magnetic powder core prepared by any one of claims 6-10.

12. The application of the magnetic powder core according to claim 11 in inductors and / or transformers.

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