Atomized metal powder, insulating coating agent, magnetic powder core, and method for producing the same

Abstract

The application relates to the technical field of electromagnetism, in particular to an atomized metal powder, an insulating coating agent, a magnetic powder core and a preparation method thereof. The atomized metal powder has 0-5 pits on the surface of the particles, and the surface of the atomized metal powder has an insulating coating layer, which is obtained by coating the atomized metal powder with the insulating coating agent; wherein the shape of the pit is a semi-spherical type, the opening diameter is 0.2-10 microns, and the depth is 0.1-0.5 microns; the insulating coating agent comprises 200 parts by weight of a resin composition; wherein the resin composition is composed of an epoxy resin and an organic silicon resin, and the weight ratio of the epoxy resin to the organic silicon resin is (2:3)-(3:2); 2-3 parts by weight of an emulsifier; 200-240 parts by weight of water; 70-90 parts by weight of a cosolvent; and 1-3 parts by weight of nano silicon dioxide.

Description

Technical Field

[0001] This application relates to the field of electromagnetic technology, and in particular to an atomized metal powder, an insulating coating agent, a magnetic powder core, and a method for preparing the same. Background Technology

[0002] Due to factors such as the manufacturing process, the surface of atomized spherical powder particles is prone to depressions. There are two main reasons for these depressions: First, when a crust forms on the surface of the atomized metal powder particles but the interior is still molten, collisions between the powder particles due to incomplete solidification cause depressions. Second, the breakage of non-standard spherical powder particles (such as comet-shaped or dumbbell-shaped particles) results in crater-like pits.

[0003] In traditional insulation coating processes, pits on the surface of atomized metal powder particles reduce the coating effect. Taking amorphous powder as an example, during the pressing of magnetic powder cores, pits in the coated amorphous powder can cause damage to the coating layer, resulting in a decrease in the electromagnetic properties of the magnetic powder core. Summary of the Invention

[0004] This application provides an atomized metal powder, an insulating coating agent, a magnetic powder core, and a method for preparing the same. The atomized metal powder particles have pits on their surface and are coated with an insulating coating layer that has good toughness and ductility. In particular, the pits on the surface of the amorphous powder particles prepared by the atomization powder preparation method can interlock during the pressing of the magnetic powder core, effectively improving the forming density of the magnetic powder core. The insulating coating layer covering the surface of the amorphous powder particles has good toughness and ductility, and can remain intact on the surface of the amorphous powder particles during the pressing process, thereby ensuring the electromagnetic properties of the magnetic powder core.

[0005] In a first aspect, an atomized metal powder is provided, wherein the particle surface of the atomized metal powder has 0-5 pits, and the particle surface of the atomized metal powder has an insulating coating layer, the coating layer being obtained by coating the atomized metal powder with an insulating coating agent; wherein the pits are hemispherical in shape, with an opening diameter of 0.2-10 μm and a depth of 0.1-0.5 μm; the insulating coating agent comprises: 200 parts by weight of a resin composition; wherein the resin composition is composed of epoxy resin and silicone resin, and the weight ratio of epoxy resin to silicone resin is (2:3)-(3:2); 2-3 parts by weight of an emulsifier; 200-240 parts by weight of water; 70-90 parts by weight of a co-solvent; and 1-3 parts by weight of nano-silica.

[0006] In one embodiment, the atomic percentage of elements in the atomized metal powder is as shown in formula (1):

[0007] Fe 100-a-b-c-d-e-f-g B a Pb Si c C d Cr e Mn f Nb g (1)

[0008] Among them, 74.7≤100-abcdefg≤84.8, 8.7≤a≤18.4, 3.0≤b≤4.5, 0.5≤c≤5.0, 0≤d≤4.0, 0≤e≤2.8, 0.1≤f≤0.5, 0≤g≤2.5.

[0009] In one embodiment, the insulating coating agent comprises: 2.5 parts by weight of emulsifier; 220 parts by weight of water; 80 parts by weight of co-solvent; and 2 parts by weight of nano-silica.

[0010] In one embodiment, the thickness of the insulating coating agent covering the particle surface of the atomized metal powder is 20nm-200nm.

[0011] In one embodiment, the insulating coating agent further includes: 5 parts by weight of an aqueous rust inhibitor, and / or 0.5 parts by weight of a reaction accelerator.

[0012] In one embodiment, the epoxy resin is any one or any combination of E-55, E-51, and E-44; the silicone resin is any one or any combination of amino-terminated silicone resin, carboxyl-terminated silicone resin, and hydroxyl-terminated silicone resin; the emulsifier is any one or any combination of sodium dodecylbenzenesulfonate, Tween-20, OP-10, and MS-1; the cosolvent is any one or any combination of acetone, isopropanol, dipropylene glycol methyl ether, and dipropylene glycol ethyl ether; and the nano-silica has a particle size of 0.5 μm to 3 μm.

[0013] In a second aspect, an atomized metal powder insulating coating agent is provided, the insulating coating agent comprising: 200 parts by weight of a resin composition; wherein the resin composition is composed of epoxy resin and silicone resin, and the weight ratio of epoxy resin to silicone resin is (2:3)-(3:2); 2-3 parts by weight of an emulsifier; 200-240 parts by weight of water; 70-90 parts by weight of a co-solvent; and 1-3 parts by weight of nano-silica.

[0014] In one embodiment, the insulating coating agent comprises: 2.5 parts by weight of emulsifier; 220 parts by weight of water; 80 parts by weight of co-solvent; and 2 parts by weight of nano-silica.

[0015] In one embodiment, the insulating coating agent further includes: 5 parts by weight of an aqueous rust inhibitor, and / or 0.5 parts by weight of a reaction accelerator.

[0016] In one embodiment, the epoxy resin is any one or any combination of E-55, E-51, and E-44; the silicone resin is any one or any combination of amino-terminated silicone resin, carboxyl-terminated silicone resin, and hydroxyl-terminated silicone resin; the emulsifier is any one or any combination of sodium dodecylbenzenesulfonate, Tween-20, OP-10, and MS-1; the cosolvent is any one or any combination of acetone, isopropanol, dipropylene glycol methyl ether, and dipropylene glycol ethyl ether; and the nano-silica has a particle size of 0.5 μm to 3 μm.

[0017] Thirdly, a method for preparing atomized metal powder as described in the first aspect is provided, comprising: preparing a first atomized metal powder, wherein the first atomized metal powder is non-standard spherical, the non-standard spherical shape including comet-shaped and dumbbell-shaped; adding the first atomized metal powder to a kneader; setting the coating parameters of the kneader; adding an insulating coating agent and water as described in the second aspect to the kneader to perform insulating coating on the first atomized metal powder, thereby obtaining atomized metal powder with an insulating coating layer; wherein 100g of the insulating coating agent is added for every 2kg of the first atomized metal powder.

[0018] In one embodiment, the coating parameters include: a stirring speed of 60 r / min and a coating temperature of 100°C.

[0019] Fourthly, a method for preparing the insulating coating agent as described in the second aspect is provided, comprising: step (1), adding 60 parts by weight of a resin composition, 35-45 parts by weight of a co-solvent, 100-120 parts by weight of water, 1-1.5 parts by weight of an emulsifier, and 1-3 parts by weight of nano-silica to a reaction vessel; wherein the resin composition is composed of epoxy resin and silicone resin, and the weight ratio of epoxy resin to silicone resin is (2:3)-(3:2); step (2), maintaining the reaction temperature at 80℃-90℃ and setting the stirring speed to 800r / min until fully saturated. Mix for 30 minutes; Step (3), add 1-1.5 parts by weight of emulsifier and 100-120 parts by weight of water to the reaction vessel at a dropping rate of 0.5-1.5 drops per second; and add a first mixture to the reaction vessel at a dropping rate of 0.25-0.75 drops per second, the first mixture consisting of 140 parts by weight of the resin composition and 35-45 parts by weight of the cosolvent; Step (4), continue the reaction for 1-3 hours; Step (5), after the reaction is completed, cool to room temperature and filter, the obtained filtrate is used as the insulating coating agent.

[0020] In one embodiment, in step (1), 0.25 parts by weight of reaction accelerator are added to the reaction vessel; and in step (3), another 0.25 parts by weight of reaction accelerator are added to the reaction vessel at a dropping rate of 0.5-1.5 drops per second; and / or, in step (1), 5 parts by weight of water-based rust inhibitor are added.

[0021] Fifthly, a magnetic powder core prepared from the atomized metal powder described in the first aspect is provided, wherein the magnetic powder core has a permeability ≥38 at 1MHz and a loss ≤379.38W / k at Bm=100mT and f=100kHz.

[0022] In a sixth aspect, a method for preparing a magnetic powder core as described in the fifth aspect is provided, comprising: adding a lubricant to atomized metal powder, mixing, and then pressing the magnetic powder core; heat-treating the pressed magnetic core at 500°C for 2 hours to obtain the magnetic powder core.

[0023] In one embodiment, the magnetic powder core is pressed at a pressure of 7T.

[0024] This application provides a solution with excellent toughness and ductility, effectively addressing the problems of insulation layer damage and uneven coating at depressions during the pressing process, thus offering a solution for insulating coating of depressed powder. Specifically, this insulating coating agent can be used to coat atomized metal powder with depressions on its particle surface, forming a coating layer on the particle surface. This coating layer remains intact during the pressing process of the atomized metal powder, thereby preserving the electromagnetic properties of the magnetic powder core. In particular, when amorphous powder with depressions on its particle surface is coated with this insulating coating agent, the depressions on the particle surface can interlock during the pressing process, effectively increasing the forming density of the magnetic powder core. Furthermore, the intact insulating coating layer on the particle surface enhances the electromagnetic properties of the magnetic powder core. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the various embodiments disclosed in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only a few embodiments disclosed in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a morphology diagram of an amorphous powder provided in an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be described below.

[0028] In atomized metal powder products, especially powder particles with high specific surface area, there are often a certain number of depressions. The presence of these depressions makes insulation between powder particles difficult, and when using conventional insulation coating methods, the insulation layer is more prone to damage during the core pressing and molding stage.

[0029] This application provides an insulating coating agent, which is an aqueous organic coating emulsion. It possesses good toughness and ductility, effectively solving the problems of insulation layer damage and uneven coating at depressions during the pressing process, thus providing a solution for insulating coating of depressed powder. Specifically, this insulating coating agent can be used to coat atomized metal powder with pits on its particle surface, forming a coating layer on the particle surface of the atomized metal powder. This coating layer remains intact during the pressing process of the atomized metal powder, thereby preserving the electromagnetic properties of the magnetic powder core.

[0030] Taking amorphous powder, a type of atomized metal powder, as an example, amorphous powder with pits on the particle surface (such as...) Figure 1 (As indicated by the arrow in the image) When coated with this insulating coating agent, the pits on the particle surface can interlock during the pressing of the magnetic powder core, effectively increasing the molding density of the magnetic powder core. Furthermore, the insulating coating layer on the particle surface remains intact, thereby improving the electromagnetic properties of the magnetic powder core.

[0031] Next, the insulating coating agent provided in the embodiments of this application will be described.

[0032] In some embodiments, the insulating coating agent may include: 200 parts by weight of a resin composition, 2-3 parts by weight of an emulsifier, 200-240 parts by weight of water, 70-90 parts by weight of a co-solvent, and 1-3 parts by weight of nano-silica. The resin composition comprises epoxy resin and silicone resin, and the weight ratio of epoxy resin to silicone resin is (2:3)-(3:2).

[0033] In some embodiments, the insulating coating agent may consist of 200 parts by weight of a resin composition, 2-3 parts by weight of an emulsifier, 200-240 parts by weight of water, 70-90 parts by weight of a co-solvent, and 1-3 parts by weight of nano-silica. The resin composition comprises epoxy resin and silicone resin, and the weight ratio of epoxy resin to silicone resin is (2:3)-(3:2).

[0034] Next, in specific embodiments, the insulating coating agent will be described.

[0035] Example 1

[0036] The insulating coating agent consists of 200 parts by weight of a resin composition, 2.5 parts by weight of an emulsifier, 220 parts by weight of water, 80 parts by weight of a co-solvent, and 2 parts by weight of nano-silica. The resin composition comprises epoxy resin and silicone resin, with a weight ratio of epoxy resin to silicone resin of (2:3)–(3:2). In one example, the weight ratio of epoxy resin to silicone resin is 2:3. In another example, the weight ratio of epoxy resin to silicone resin is 1:1. In yet another example, the weight ratio of epoxy resin to silicone resin is 3:2.

[0037] The insulating coating agent in Example 1 can be prepared in the following manner.

[0038] Add 60 parts by weight of the resin composition, 40 parts by weight of the co-solvent, 110 parts by weight of water, 1.25 parts by weight of the emulsifier, and 2 parts by weight of nano-silica to a reaction vessel (e.g., a three-necked flask). Place the reaction vessel in a water bath and adjust the temperature of the water bath to 80°C-90°C. Set the stirring speed to 800 rpm and mix thoroughly for 30 minutes.

[0039] Then, add 1.25 parts by weight of emulsifier and 110 parts by weight of water to the reaction vessel at a dropping rate of 0.5-1.5 drops per second. Mix 140 parts by weight of the resin composition and 40 parts by weight of the co-solvent thoroughly, and then add this mixture dropwise to the reaction vessel at a dropping rate of 0.25-0.75 drops per second. After the addition is complete, continue the reaction for 1-3 hours. After the reaction is complete, cool to room temperature and filter through a 100-mesh sieve. The filtrate is pale blue, which is the insulating coating agent.

[0040] Example 2

[0041] The insulating coating agent consists of 200 parts by weight of a resin composition, 2.5 parts by weight of an emulsifier, 220 parts by weight of water, 80 parts by weight of a co-solvent, 2 parts by weight of nano-silica, and 5 parts by weight of a water-based rust inhibitor. The resin composition comprises epoxy resin and silicone resin, with a weight ratio of epoxy resin to silicone resin of (2:3)–(3:2).

[0042] The insulating coating agent in Example 2 can be prepared in the following manner.

[0043] Add 60 parts by weight of the resin composition, 40 parts by weight of the co-solvent, 110 parts by weight of water, 1.25 parts by weight of the emulsifier, 2 parts by weight of nano-silica, and 5 parts by weight of the water-based rust inhibitor to a reaction vessel (e.g., a three-necked flask). Place the reaction vessel in a water bath and adjust the temperature of the water bath to 80°C-90°C. Set the stirring speed to 800 rpm and mix thoroughly for 30 minutes.

[0044] Then, add 1.25 parts by weight of emulsifier and 110 parts by weight of water to the reaction vessel at a dropping rate of 0.5-1.5 drops per second. Mix 140 parts by weight of the resin composition and 40 parts by weight of the co-solvent thoroughly, and then add this mixture dropwise to the reaction vessel at a dropping rate of 0.25-0.75 drops per second. After the addition is complete, continue the reaction for 1-3 hours. After the reaction is complete, cool to room temperature and filter through a 100-mesh sieve. The filtrate is pale blue, which is the insulating coating agent.

[0045] Example 3

[0046] The insulating coating agent consists of 200 parts by weight of a resin composition, 2.5 parts by weight of an emulsifier, 220 parts by weight of water, 80 parts by weight of a co-solvent, 2 parts by weight of nano-silica, 0.5 parts by weight of a reaction accelerator, and 5 parts by weight of a water-based rust inhibitor. The resin composition comprises epoxy resin and silicone resin, with a weight ratio of epoxy resin to silicone resin of (2:3)–(3:2).

[0047] The insulating coating agent in Example 3 can be prepared in the following manner.

[0048] Add 60 parts by weight of the resin composition, 40 parts by weight of the co-solvent, 110 parts by weight of water, 1.25 parts by weight of the emulsifier, 0.25 parts by weight of the reaction accelerator, 2 parts by weight of nano-silica, and 5 parts by weight of the water-based rust inhibitor to a reaction vessel (e.g., a three-necked flask). Place the reaction vessel in a water bath and adjust the temperature of the water bath to 80°C-90°C. Set the stirring speed to 800 rpm and mix thoroughly for 30 minutes.

[0049] Then, add 1.25 parts by weight of emulsifier, 0.25 parts by weight of reaction accelerator, and 110 parts by weight of water to the reaction vessel at a dropping rate of 0.5-1.5 drops per second. Mix 140 parts by weight of resin composition and 40 parts by weight of cosolvent thoroughly, and then add this mixture dropwise to the reaction vessel at a dropping rate of 0.25-0.75 drops per second. After the addition is complete, continue the reaction for 1-3 hours. After the reaction is complete, cool to room temperature and filter through a 100-mesh sieve. The filtrate is pale blue, which is the insulating coating agent.

[0050] In the above embodiments, the epoxy resin is any one or a combination of E-55, E-51, and E-44. The silicone resin is any one or a combination of amino-terminated silicone resin, carboxyl-terminated silicone resin, and hydroxyl-terminated silicone resin. The emulsifier is any one or a combination of sodium dodecylbenzenesulfonate, Tween-20, OP-10, and MS-1. The cosolvent is any one or a combination of acetone, isopropanol, dipropylene glycol methyl ether, and dipropylene glycol ethyl ether. The nano-silica has a particle size of 0.5 μm-3 μm. The water-based rust inhibitor is one or a combination of two of long-chain carboxylic acid esters and triethanolamine borate. The reaction promoter is one or more of triethylamine, DMP-30, imidazole, and boron trifluoride complex.

[0051] Among them, epoxy resin contains highly active epoxy bonds and hydroxyl groups, and its resin system also has a large number of highly polar ether bonds and ester bonds. These chemical structures enable the emulsion to have good adhesion to amorphous powder. Due to its good electrical insulation properties, organosilicon resin mainly plays an electrical insulation role when coating powder.

[0052] The addition of water-based rust inhibitors can effectively prevent the oxidation of iron-based amorphous powder during the insulation passivation process, thereby ensuring that the powder maintains optimal electromagnetic properties when fabricating molded devices.

[0053] Next, three examples of insulating coating agents are prepared.

[0054] Coating agent A is composed of the following components (all in parts by weight).

[0055]

[0056] Coating agent B is composed of the following components (all in parts by weight).

[0057]

[0058] Coating agent C is composed of the following components (all in parts by weight).

[0059]

[0060] The above example describes an insulating coating agent. Next, the example describes an amorphous powder provided in an embodiment of this application.

[0061] The amorphous powder provided in this application embodiment has 0-5 pits on its particle surface, and the particle surface of the amorphous powder has an insulating coating layer, which is obtained by coating the amorphous powder with the aforementioned insulating coating agent. In one example, the amorphous powder particle surface has 1 pit. In one example, the amorphous powder particle surface has 2 pits. In one example, the amorphous powder particle surface has 3 pits. In one example, the amorphous powder particle surface has 4 pits. In one example, the amorphous powder particle surface has 5 pits.

[0062] In some embodiments, the atomic percentage of elements in the amorphous powder is as shown in formula (1):

[0063] Fe 100-a-b-c-d-e-f-g B a P b Si c C d Cr e Mn f Nb g (1)

[0064] Among them, 74.7≤100-abcdefg≤84.8, 8.7≤a≤18.4, 3.0≤b≤4.5, 0.5≤c≤5.0, 0≤d≤4.0, 0≤e≤2.8, 0.1≤f≤0.5, 0≤g≤2.5.

[0065] The pits on the surface of amorphous powder particles can be hemispherical. The opening diameter of the pits on the surface of amorphous powder particles is 0.2-10 μm and the depth is 0.1-0.5 μm.

[0066] The pits on the surface of amorphous powder particles can be crater-like pits caused by the fracture of non-standard spheres or non-spherical powders (e.g., comet-shaped powders, dumbbell-shaped powders, etc.).

[0067] The pits on the surface of amorphous powder particles can be caused by the collisions between molten amorphous powder particles during the amorphous powder production process, when the molten powder is in a molten state inside an outer shell. Because the amorphous powder is not completely solidified, these collisions result in pits on the particle surface.

[0068] The pits on the surface of amorphous powder particles can interlock with each other during the pressing of magnetic powder cores, thereby effectively improving the forming density of magnetic powder cores.

[0069] In some embodiments, the thickness of the insulating coating agent covering the surface of the amorphous powder particles is 20 nm to 200 nm.

[0070] The insulating coating layer on the surface of amorphous powder particles has good toughness and ductility. During the pressing process of magnetic powder core, it can remain intact on the surface of amorphous powder particles, thereby ensuring the electromagnetic performance of magnetic powder core.

[0071] Next, we will introduce the preparation process of amorphous powder.

[0072] Initial amorphous powder can be prepared using amorphous powder preparation processes (such as atomization powder preparation processes). Initial amorphous powder refers to amorphous powder prepared using these processes but not yet subjected to insulating coating. Initial amorphous powder is non-standard spherical in shape, such as comet-shaped or dumbbell-shaped.

[0073] Two kilograms of initial amorphous powder were added to a kneader, and the kneader's coating parameters were set. The stirring speed was set to 60 rpm, and the coating temperature to 100°C. Then, a homogeneous mixture of 100g of insulating coating agent and 120g of distilled water was slowly added to the kneader. After the powder was completely fluidized, the coated powder was removed and sieved through a 200-mesh sieve, yielding amorphous powder with pitted surfaces and an insulating coating layer.

[0074] During the coating process, comet-shaped, dumbbell-shaped, and other amorphous powders may break, resulting in pits in the amorphous powder. Because the insulating coating agent provided in this application has good toughness and ductility, it can coat these pits, ensuring that the entire surface of the amorphous powder particles is covered with an insulating layer. In other words, even if the amorphous powder breaks, the insulating coating agent provided in this application can form a complete insulating coating layer on the surface of the broken amorphous powder.

[0075] This application also provides magnetic powder properties prepared from the amorphous powder described above. The magnetic powder core exhibits a permeability ≥38 at 1MHz and a loss ≤379.38W / k at Bm=100mT and f=100kHz.

[0076] It can be prepared in the following way.

[0077] Take 500g of the sieved amorphous powder, add 0.3%-0.5% (by weight, i.e., the weight of the lubricant to the weight of the amorphous powder) of lubricant, mix thoroughly, and then press into a magnetic ring. The dimensions of the pressed magnetic ring are 14mm outer diameter, 8mm inner diameter, and 3mm height. The pressing pressure is 7T. The pressed amorphous magnetic powder core is then heat-treated at 500℃ for 2 hours to relieve internal stress. Then, the electromagnetic properties of the heat-treated amorphous magnetic powder core are tested. The magnetic powder core can also be referred to as a magnetic ring.

[0078] The electromagnetic properties of amorphous magnetic powder cores prepared using amorphous powders coated with different insulating coatings are shown in Table 1. In the examples and comparative examples shown in Table 1, the amorphous powder preparation process and the magnetic powder core preparation process are the same; the difference lies in the insulating coating.

[0079] Table 1

[0080]

[0081]

[0082] As shown in Table 1, compared to the traditional water glass coating method, in the coating method using the coating agent provided in this application embodiment, for the same weight of amorphous powder used to press magnetic rings, the magnetic ring height of the magnetic powder pressed from the amorphous powder coated with the coating agent provided in this application embodiment is lower than that of the magnetic powder coated with water glass, i.e., the pressing density is higher. Compared to the amorphous powder coated with water glass, the magnetic rings pressed from the amorphous powder coated with the coating agent provided in this application embodiment show significant improvements in both loss performance and permeability. Among them, when considering both the loss characteristics and permeability characteristics of the magnetic powder core, the magnetic rings pressed from the amorphous powder coated with coating agent B have better overall performance.

[0083] Furthermore, when using water glass for insulation coating, the thicker coating layer generally results in lower losses during the pressing of the magnetic powder core. However, due to the higher proportion of non-magnetic materials within the magnetic powder core, the permeability of the core is lower. Therefore, the water glass insulation coating scheme is not suitable for pressing devices with high permeability.

[0084] The following describes the selection of the optimal insulation passivation scheme using different dosages of insulating coating agent B for insulation coating.

[0085] First, initial amorphous powder from the same batch was selected, with an initial powder particle size D50 = 30.51 μm. Using the same coating process, different dosages of insulating coating agent B were applied for insulating coating to obtain coated amorphous powder. The same mass of amorphous powder was weighed and pressed into magnetic rings of the same size under the same pressing parameters. A more detailed implementation process follows:

[0086] Comparative Example D2: 2 kg of initial amorphous powder with a particle size D50 = 30.51 μm was weighed into a kneader, along with 80 g of insulating coating agent B and 100 g of distilled water. The reaction temperature was 90℃. After the amorphous powder was completely fluidized, it was sieved using a 100-mesh sieve. 2 g of the sieved amorphous powder was weighed and pressed into a magnetic powder core with dimensions of 14*8*3 mm using a pressure of 7T. The magnetic powder core was then heat-treated at 500℃ for 2 hours to relieve internal stress. The electromagnetic properties of the heat-treated amorphous magnetic powder core were tested. The results are shown in Table 2.

[0087] In Example S2, 2 kg of initial amorphous powder with a particle size D50 = 30.51 μm was weighed into a kneader, along with 100 g of insulating coating agent B and 100 g of distilled water. The reaction temperature was 90 °C. After the amorphous powder was completely fluidized, it was sieved using a 100-mesh sieve. 2 g of the sieved amorphous powder was weighed and pressed into a magnetic powder core with dimensions of 14*8*3 mm using a pressure of 7T. The magnetic powder core was then heat-treated at 500 °C for 2 hours to relieve internal stress. The electromagnetic properties of the heat-treated amorphous magnetic powder core were tested. The results are shown in Table 2.

[0088] Comparative Example D3: 2 kg of initial amorphous powder with a particle size D50 = 30.51 μm was weighed into a kneader, along with 120 g of insulating coating agent B and 100 g of distilled water. The reaction temperature was 90℃. After the amorphous powder was completely fluidized, it was sieved using a 100-mesh sieve. 2 g of the sieved amorphous powder was weighed and pressed into a magnetic powder core with dimensions of 14*8*3 mm using a pressure of 7T. The magnetic powder core was then heat-treated at 500℃ for 2 hours to relieve internal stress. The electromagnetic properties of the heat-treated amorphous magnetic powder core were tested. The results are shown in Table 2.

[0089] Comparative Example D4: 2 kg of initial amorphous powder with a particle size D50 = 30.51 μm was weighed into a kneader, along with 150 g of insulating coating agent B and 100 g of distilled water. The reaction temperature was 90℃. After the amorphous powder was completely fluidized, it was sieved using a 100-mesh sieve. 2 g of the sieved amorphous powder was weighed and pressed into a magnetic powder core with dimensions of 14*8*3 mm using a pressure of 7T. The magnetic powder core was then heat-treated at 500℃ for 2 hours to relieve internal stress. The electromagnetic properties of the heat-treated amorphous magnetic powder core were tested. The results are shown in Table 2.

[0090] Table 2

[0091]

[0092] As can be seen from Table 2, when the amount of insulating coating agent B is 5% (i.e., the weight of insulating coating agent B divided by the weight of the initial amorphous powder), the loss of the magnetic powder core is [value missing]. m The permeability is 379.38 W / kg at 100 mT and f = 100 kHz, and 38 at 1 MHz. The magnetic powder core prepared under these conditions has better overall performance.

[0093] Next, using amorphous recessed powder and amorphous spherical powder as coating targets, experiments were conducted using insulating coating agent B to verify the performance of the insulating coating agent provided in this application for amorphous recessed powder and amorphous spherical powder. Here, amorphous recessed powder can be simply referred to as recessed powder, and amorphous spherical powder can be simply referred to as spherical powder.

[0094] The specific implementation plan is as follows: 2 kg of concave or spherical powder with different particle sizes is weighed into a kneader, along with 100 g of insulating coating agent B and 100 g of distilled water. The reaction temperature is 90℃. After the powder is completely fluidized, it is sieved using a 100-mesh sieve. 2 g of the sieved powder is weighed and pressed into a magnetic powder core with dimensions of 14*8*3 mm using a pressure of 7T / 10T / 12T. The magnetic powder core is then heat-treated at 500℃ for 2 hours to relieve internal stress. The electromagnetic properties of the heat-treated amorphous magnetic powder core are tested. The results are shown in Table 3.

[0095] Table 3

[0096]

[0097] As shown in Table 3, both powders exhibit low loss characteristics after heat treatment when using low pressing pressure (7T). With increasing pressing pressure, the concave amorphous powder first shows a significant increase in loss and magnetic permeability. This is mainly because the edges of the concave pits in the concave powder are sharper than those of the spherical surface. At high pressing pressure, these sharp points are more likely to pierce the coating layer, causing damage to the insulation layer and consequently increasing both magnetic permeability and loss. At low pressing pressure, the concave parts of the concave powder are more likely to form surface contact with each other compared to the spherical powder, making it easier to create a high-density magnetic powder core during pressing. Therefore, the concave spherical powder has a lower pressing height and higher magnetic permeability.

[0098] Therefore, using concave powder with a pressing pressure of 7T and a particle size of about 30μm for insulation coating, the magnetic core after pressing and heat treatment has better magnetic properties, with a permeability of 43 at 1MHz and a loss of 362.23W / kg at Bm=100mT and f=100kHz.

[0099] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above description is only a specific embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing atomized metal powder, characterized in that, include: A first atomized metal powder is prepared, wherein the first atomized metal powder is non-standard spherical, and the non-standard spherical shape includes comet-shaped and dumbbell-shaped; wherein the surface of the first atomized metal powder particles has 1-5 pits, the shape of the pits is hemispherical, the opening diameter is 0.2-10μm, and the depth is 0.1-0.5μm; The first atomized metal powder is added to the kneader; The coating parameters of the kneader are set; wherein, the coating parameters include: stirring speed of 60 r / min and coating temperature of 100℃; An insulating coating agent and water are added to the kneader to insulatingly coat the first atomized metal powder, thereby obtaining atomized metal powder with an insulating coating layer; wherein, 100g of the insulating coating agent is added for every 2kg of the first atomized metal powder; The method for preparing the insulating coating agent includes: Step (1): Add 60 parts by weight of resin composition, 35-45 parts by weight of cosolvent, 100-120 parts by weight of water, 1-1.5 parts by weight of emulsifier, and 1-3 parts by weight of nano-silica to the reaction vessel; wherein the resin composition is composed of epoxy resin and silicone resin, and the weight ratio of epoxy resin to silicone resin is (2:3)-(3:2); Step (2): Maintain the reaction temperature at 80℃-90℃ and set the stirring speed to 800r / min to mix thoroughly for 30min; Step (3): Add 1-1.5 parts by weight of emulsifier and 100-120 parts by weight of water to the reaction vessel at a dropping rate of 0.5-1.5 drops per second; and add a first mixture to the reaction vessel at a dropping rate of 0.25-0.75 drops per second, the first mixture consisting of 140 parts by weight of the resin composition and 35-45 parts by weight of the cosolvent. Step (4): Continue the reaction for 1-3 hours; Step (5): After the reaction is complete, cool to room temperature and filter. The resulting filtrate is used as the insulating coating agent.

2. The preparation method according to claim 1, characterized in that, In step (1), 0.25 parts by weight of reaction promoter are added to the reaction vessel; and in step (3), another 0.25 parts by weight of reaction promoter are added to the reaction vessel at a dropping rate of 0.5-1.5 drops per second. And / or, In step (1), 5 parts by weight of water-based rust inhibitor are added.

3. A magnetic powder core prepared from atomized metal powder by the preparation method of claim 1 or 2, wherein the magnetic powder core has a permeability ≥38 at 1MHz and a loss ≤379.38W / k at Bm=100mT and f=100kHz.

4. A method for preparing a magnetic powder core as described in claim 3, characterized in that, include: Lubricant is added to atomized metal powder, and after mixing, magnetic powder core pressing is performed. The pressed magnetic core is heat-treated at 500℃ for 2 hours to obtain a magnetic powder core.

5. The method according to claim 4, characterized in that, The magnetic powder core is pressed at a pressure of 7T.

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