Efficient chemical liquid coating method for metal soft magnetic powder and application thereof

Abstract

The application discloses a kind of high-efficiency chemical liquid phase coating method and application of metal soft magnetic powder, belongs to soft magnetic material preparation technical field, after dissolving aluminum isopropyl alcohol, form coating precursor solution, after hydrolysis, dehydration reaction is formed Al2O3 insulating coating on the surface of fluidized metal soft magnetic powder.The aluminum isopropyl alcohol described in the application dissolves and forms gel, and is uniformly mixed with the fluidized metal soft magnetic powder, and after high-temperature airflow drying, dry gel can be formed on the surface of metal soft magnetic powder, and further calcination dehydration forms the metal soft magnetic powder coated with high-insulation Al2O3.The application can be widely used for the surface insulation coating of metal soft magnetic powder, has the characteristics of controllable coating layer thickness, simple and fast, high coating efficiency, meets the needs of industrial production such as scale, low cost, safety and environmental protection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of soft magnetic material preparation, and more particularly relates to a high-efficiency chemical liquid-phase coating method for metal soft magnetic powder and application. BACKGROUND

[0002] Soft magnetic composites (metal magnetic powder core, SMCs) are generally pressed from insulating magnetic powder. Compared with traditional silicon steel sheets and soft magnetic ferrite, SMCs have obvious advantages such as magnetic isotropy, high Curie temperature, low loss, distributed air gap, and easy molding manufacturing, and have become a key material for magnetic components in high-frequency and high-power application scenarios.

[0003] The insulating coating layer on the surface of the metal soft magnetic powder is the key to realizing high-frequency and low-eddy-current loss of SMCs, and therefore the insulating coating is crucial for the high-frequency development of soft magnetic composites. In the production process of soft magnetic composites, it is necessary to improve the uniformity of the coating layer of the magnetic powder, and at the same time, the coating process requires low cost and high efficiency. Therefore, it is urgent to develop a low-cost and high-efficiency coating method for soft magnetic powder.

[0004] There are many related research reports on the coating method of metal soft magnetic powder. From the material composition of the coating layer, there are currently two main categories: organic coating and inorganic coating. Among them, epoxy resin, phenolic resin, silicone resin and other thermosetting polymer materials are more commonly used under low-temperature curing conditions. Phosphates formed by surface phosphating reaction or other reaction-formed SiO2, Al2O3 and other inorganic coating layers generally meet the application requirements of high-temperature annealing process.

[0005] In summary, although the organic coating layer can effectively coat the magnetic powder and fill the gap between the magnetic powders, its poor high-temperature resistance makes it at risk of decomposition failure in harsh environments. The high-temperature resistance of inorganic coating layer is good, but the general preparation method is relatively complex. These methods also have problems such as environmental unfriendliness, high cost, low coating efficiency, and uneven coating layer to some extent. SUMMARY

[0006] In view of the above defects or improvement needs of the prior art, the application provides a high-efficiency chemical liquid-phase coating method for metal soft magnetic powder and application, thereby solving the technical problems of the existing preparation method being relatively complex, low coating efficiency, and uneven coating layer.

[0007] To achieve the above-mentioned purpose, according to one aspect of the application, a high-efficiency chemical liquid-phase coating method for metal soft magnetic powder is provided, which comprises the following steps:

[0008] The powder to be coated is placed in the reaction cavity, and a fluidizing gas source is introduced into the reaction cavity to uniformly fluidize the powder in the reaction cavity;

[0009] The metal compound or the organic compound is dissolved in a solvent to form a coating precursor solution, the atomized precursor solution is sprayed into the reaction chamber and fully reacts with the powder to be coated to obtain the surface-modified metal soft magnetic powder;

[0010] The surface-modified metal soft magnetic powder is calcined to obtain the coated magnetic powder with a core-shell structure of metal soft magnetic powder, and the coated magnetic powder is mixed with a resin binder to form a green body of the metal soft magnetic composite material.

[0011] The green body of the metal soft magnetic composite material is heat treated to obtain the metal soft magnetic composite material after heating and curing or annealing.

[0012] Preferably, the metal compound includes aluminum isopropoxide, pseudo-boehmite white powder, aluminum sec-butoxide, magnesium acetate tetrahydrate or sodium silicate nonahydrate; and the organic compound includes tetraethyl orthosilicate or titanium acid tetra-n-butyl ester.

[0013] The purity of the aluminum isopropoxide, pseudo-boehmite and aluminum sec-butoxide is greater than 99%, and the aluminum content is between 5% and 30%; the purity of the tetraethyl orthosilicate, magnesium acetate tetrahydrate and sodium silicate nonahydrate is greater than 98%.

[0014] Preferably, the solvent includes a single organic solvent or a mixed solvent of deionized water, methanol, ethanol, glycerol, isopropyl alcohol or toluene.

[0015] Preferably, the metal soft magnetic powder includes at least one of carbonyl iron powder, Fe-Ni-Mo alloy powder, Fe-Ni alloy powder, Fe-Co alloy powder, Fe-Si alloy powder, Fe-Si-Al alloy powder, Fe-Si-Cr alloy powder, Fe-based amorphous alloy powder, Ni-based amorphous alloy powder, Co-based amorphous alloy powder and Fe-based nanocrystalline powder.

[0016] Preferably, the gas flow temperature of the fluidization gas source is 50°C to 600°C, the flow rate of the gas flow is 4m 3 / min to 50m 3 / min, and the speed of the gas flow is 0.4m / s to 10m / s.

[0017] Preferably, the calcination temperature is 400°C to 1000°C, and the calcination time is 1h to 3h.

[0018] Preferably, the coating precursor solution is extracted to the atomization device by a suction device, and the precursor solution spray is formed after the atomization device.

[0019] Preferably, the rotation speed of the suction device is 2r / min to 100r / min, and the gas pressure of the atomization device is 0.1Mpa to 10Mpa.

[0020] According to another aspect of the present application, there is provided an application of the metal soft magnetic composite material prepared by the efficient chemical liquid phase coating method of metal soft magnetic powder in an integrated inductor or metal soft magnetic powder core.

[0021] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0022] 1. The efficient chemical liquid phase coating method of metal soft magnetic powder proposed by the present application adopts a powder fluidization method, uses a fully atomized aluminum isopropyl alcohol solution to coat and modify the surface of the metal soft magnetic powder, and is a new idea and new process method for uniformly and efficiently coating the metal soft magnetic powder. Aluminum isopropyl alcohol, also known as organic aluminum, can effectively form a network structure through a hydrolysis and condensation process. After being uniformly mixed with metal powder and calcined and dehydrated, an Al2O3 coating layer can be formed on the surface of the soft magnetic powder. The thickness of the alumina coating layer prepared by this method is controllable, the coating is uniform, the process is simple and fast, and the needs of large-scale, low-cost, safe and low-pollution industrial production can be met.

[0023] 2. The efficient chemical liquid phase coating method of metal soft magnetic powder proposed by the present application can form a dry gel coating layer after drying at 80℃, and further calcination can be performed according to the required heat treatment temperature of the metal powder. The dry gel will be converted into an alumina coating layer of different phases at different temperatures, which greatly expands the application temperature range of the method.

[0024] 3. The efficient chemical liquid phase coating method of metal soft magnetic powder proposed by the present application uses a fluidized bed to uniformly fluidize the powder, and combines an atomizing nozzle to uniformly atomize the precursor solution. The uniformly fluidized powder and the atomized precursor solution are in contact more uniformly, so that a more uniform Al2O3 coating layer is obtained after coating. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic diagram of a coating device of the efficient chemical liquid phase coating method of metal soft magnetic powder of the present application;

[0026] Figure 2 is an SEM comparison diagram of Fe-Cr-Si-B-C soft magnetic powder before and after coating treatment by the efficient chemical liquid phase coating method of metal soft magnetic powder of the present application;

[0027] Figure 3 is an SEM result diagram of the metal soft magnetic powder prepared in Example 1 of the present application under different precursor concentrations;

[0028] Figure 4 is a powder EDS result diagram of the metal soft magnetic powder prepared in Example 1 of the present application under different precursor concentrations;

[0029] Figure 5 is a powder resistivity result chart of the metal soft magnetic powder prepared in Example 1 of the present application under different precursor concentrations;

[0030] Figure 6 is a powder resistivity result chart of the carbonyl iron powder before and after coating prepared in Example 3 of the present application;

[0031] Figure 7 is a cross-sectional TEM chart of the coated metal soft magnetic powder prepared in Example 1 of the present application;

[0032] Figure 8 is an SEM chart of the metal soft magnetic powder prepared in Example 8 of the present application;

[0033] Figure 9 is an EDS result chart of the metal soft magnetic powder prepared in Example 9 of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0035] The present application proposes a high-efficiency chemical liquid phase coating method for metal soft magnetic powder, comprising the following steps:

[0036] (1) Dissolve organic aluminum in a suitable solvent to form a coating precursor solution;

[0037] Specifically, the organic aluminum is aluminum isopropoxide, white powder such as pseudo-boehmite, and other common aluminum sols such as aluminum sec-butoxide, with a purity of more than 99% and an aluminum content of about 5% to 30%. The solvent is deionized water, methanol, ethanol, glycerol, isopropyl alcohol, toluene and other common organic solvents and their mixed solvents;

[0038] (2) The coating precursor solution is extracted by a suction device, and after passing through an atomization device, the coating precursor forms a uniform precursor spray in the reaction cavity.

[0039] Specifically, the suction device is generally a peristaltic pump, a suction device or other devices with controllable liquid transport capacity; the atomization device is generally an ultrasonic atomizer, a pneumatic atomizer, a mechanical atomizer, an electric atomizer or other common liquid spray devices; the reaction cavity is a cylindrical reaction container, which is the coating reaction area of the fluidized powder.

[0040] (3) Put the powder to be coated into the reaction chamber of step (2), and adjust the fluidizing gas source of the reaction chamber to make the powder uniformly fluidized in the reaction chamber.

[0041] Specifically, the fluidizing gas source is a high-speed hot gas stream passing through the reaction chamber from bottom to top, which makes the powder uniformly fluidized in the reaction chamber. The fluidizing gas source has a certain temperature, so that the precursor solution can quickly solidify on the surface of the powder. The reaction chamber has a stirrer at the bottom to prevent the powder from accumulating in the corners of the reaction chamber.

[0042] (4) Turn on the suction device and the atomization device. After the precursor solution is completely introduced into the reaction chamber, the reaction is completed, and the surface-modified metal soft magnetic powder is obtained.

[0043] (5) After the modified metal soft magnetic powder is calcined at high temperature, the metal soft magnetic powder with Al2O3 core-shell structure is obtained.

[0044] (6) Add a resin binder to the coated magnetic powder in step (5), mix and granulate, and then press into a shape.

[0045] (7) Heat treat the green body of the metal soft magnetic composite material obtained in step (6) to complete the heating and curing or annealing treatment, and then the metal soft magnetic composite material is obtained.

[0046] Further, the temperature of the reaction chamber in step (4) can be increased to 600°C or higher, so that the calcination step can be omitted, and the aluminum oxide-coated metal soft magnetic powder can be directly obtained.

[0047] Further, the solvent is generally deionized water, and organic solvents such as methanol, ethanol, propanol, isopropanol, toluene, etc. can be added to the solvent to adjust its reaction characteristics. The mass ratio of the organic solvent to the deionized water is 1:10 ~ 10:1.

[0048] Further, the aluminum isopropoxide accounts for 0.1% ~ 10% of the total mass of the solution.

[0049] Further, the aluminum isopropoxide accounts for 0.1% ~ 20% of the mass of the metal soft magnetic powder.

[0050] Further, the organic aluminum in step (1) can be replaced by metal compounds such as magnesium acetate tetrahydrate, sodium silicate nonahydrate, or organic compounds such as tetraethyl orthosilicate or titanium acid tetra-n-butyl ester.

[0051] The technical solutions of the present application will be further described through specific examples.

[0052] Example 1

[0053] The embodiment provides a high-efficiency chemical liquid phase coating method of a metal soft magnetic powder, which comprises the following steps:

[0054] (1) 36 mL of deionized water and 100 mL of an ethanol solution are uniformly mixed, and 10 g of aluminum isopropoxide is added into the solution to obtain an aluminum isopropoxide precursor solution.

[0055] (2) 1000 g of Fe-Cr-Si-B-C amorphous soft magnetic powder is placed at the bottom of a reaction cavity, a fluidized gas flow temperature is set to 80 DEG C, a peristaltic pump and an atomizing nozzle are turned on, and reaction is continuously carried out.

[0056] (3) The dry gel coated Fe-Cr-Si-B-C powder is placed in a muffle furnace, calcined at 500 DEG C for 1 h under a nitrogen protective atmosphere, and coated powder is obtained.

[0057] (4) 100 g of the coated Fe-Cr-Si-B-C powder and 2 g of a resin (20 ml of an acetone solvent) solution are fully stirred, sieved after the solvent is completely volatilized, and Fe-Cr-Si-B-C alloy powder granules are obtained, with a particle size interval of 40 mesh to 200 mesh.

[0058] (5) The granulated powder is pressed at 600 MPa to obtain a soft magnetic composite green body.

[0059] (6) The green body is cured at 200 DEG C for 1 h in an air atmosphere, and a soft magnetic composite sample is obtained.

[0060] Embodiment 2

[0061] The embodiment provides a high-efficiency chemical liquid phase coating method of a metal soft magnetic powder, which comprises the following steps:

[0062] (1) 36 mL of deionized water and 100 mL of an ethanol solution are uniformly mixed, and 10 g of aluminum isopropoxide is added into the solution to obtain an aluminum isopropoxide precursor solution.

[0063] (2) 1000 g of Fe-Cr-Si-B-C amorphous soft magnetic powder is placed at the bottom of a reaction cavity, a fluidized gas flow temperature is set to 80 DEG C, a peristaltic pump and an atomizing nozzle are turned on, and reaction is continuously carried out.

[0064] (3) The dry gel coated Fe-Cr-Si-B-C powder is placed in a muffle furnace, calcined at 500 DEG C for 1 h under a nitrogen protective atmosphere, and coated powder is obtained.

[0065] (4) Take 100 g of Fe-Cr-Si-B-C powder after coating modification and 2 g of resin (20 ml of acetone solvent) solution, fully stir, wait for the solvent to volatilize completely, sieve, get Fe-Cr-Si-B-C alloy powder granulation, particle size interval is 40-200 mesh.

[0066] (5) The granulation powder is pressed at 2000 MPa to obtain a soft magnetic composite green body.

[0067] (6) The green body is annealed at 500 DEG C for 1 hour in a nitrogen atmosphere to obtain a soft magnetic composite sample.

[0068] Example 3

[0069] The embodiment provides a high-efficiency chemical liquid phase coating method of metal soft magnetic powder, which comprises the following steps:

[0070] (1) Take 38 mL of deionized water and 100 mL of ethanol solution, uniformly mix, add 12 g of aluminum isopropyl alcohol to obtain an aluminum isopropyl alcohol precursor solution.

[0071] (2) Take 1000 g of carbonyl iron powder and place it at the bottom of the reaction cavity, set the fluidized gas flow temperature to 80 DEG C, start the peristaltic pump and the atomizing nozzle to ensure continuous reaction.

[0072] (3) The dry gel coated Fe-Cr-Si-B-C powder is placed in a muffle furnace and calcined at 500 DEG C for 1 h under a nitrogen protective atmosphere to obtain coated powder.

[0073] (4) Take 100 g of Fe-Cr-Si-B-C powder after coating modification and 2 g of resin (20 ml of acetone solvent) solution, fully stir, wait for the solvent to volatilize completely, sieve, get Fe-Cr-Si-B-C alloy powder granulation, particle size interval is 40-200 mesh.

[0074] (5) The granulation powder is pressed at 600 MPa to obtain a soft magnetic composite green body.

[0075] (6) The green body is cured at 200 DEG C for 1 hour in an air atmosphere to obtain a soft magnetic composite sample.

[0076] Example 4

[0077] The embodiment provides a high-efficiency chemical liquid phase coating method of metal soft magnetic powder, which comprises the following steps:

[0078] (1) Take 38 mL of deionized water and 100 mL of ethanol solution, uniformly mix, add 12 g of aluminum isopropyl alcohol to obtain an aluminum isopropyl alcohol precursor solution.

[0079] (2) Take 1000g of carbonyl iron powder and place it at the bottom of the reaction chamber. Set the fluidized gas flow temperature to 80°C. Turn on the peristaltic pump and the atomizing nozzle to ensure continuous reaction.

[0080] (3) Take 1000g of Fe-Cr-Si-B-C powder and place it at the bottom of the reaction chamber. Set the fluidized gas flow temperature to 80°C. Turn on the peristaltic pump and the atomizing nozzle to ensure continuous reaction.

[0081] (3) Place the two types of powder coated with xerogel in a muffle furnace and calcine them at 500°C for 1 hour under a nitrogen atmosphere to obtain the coated powders.

[0082] (4) Take 50g of each of the modified Fe-Cr-Si-B-C powders and mix them with 2g of resin (20ml of acetone solvent) solution. Stir thoroughly and sieve after the solvent has completely evaporated to obtain the granulated powder with a particle size range of 40-200 mesh.

[0083] (5) Press the granulated powder at 600MPa to obtain the soft magnetic composite material green body.

[0084] (6) Cure the green body at 200°C for 1 hour in an air atmosphere to obtain the soft magnetic composite material sample.

[0085] Example 5

[0086] The embodiment provides a high-efficiency chemical liquid phase coating method for metal soft magnetic powder, which comprises the following steps:

[0087] (1) Mix 38mL of deionized water with 100mL of ethanol solution uniformly, and then add 12g of aluminum isopropoxide to obtain an aluminum isopropoxide precursor solution.

[0088] (2) Take 1000g of carbonyl iron powder and place it at the bottom of the reaction chamber. Set the fluidized gas flow temperature to 500°C. Turn on the peristaltic pump and the atomizing nozzle to ensure continuous reaction.

[0089] (3) Take 100g of modified Fe-Cr-Si-B-C powder and mix it with 2g of resin (20ml of acetone solvent) solution. Stir thoroughly and sieve after the solvent has completely evaporated to obtain the Fe-Cr-Si-B-C alloy powder granulated material with a particle size range of 40-200 mesh.

[0090] (4) Press the granulated powder at 600MPa to obtain the soft magnetic composite material green body.

[0091] (5) Cure the green body at 200°C for 1 hour in an air atmosphere to obtain the soft magnetic composite material sample.

[0092] Example 6

[0093] The embodiment provides a high-efficiency chemical liquid phase coating method of a metal soft magnetic powder, which comprises the following steps:

[0094] (1) uniformly mix 38 mL of deionized water and 100 mL of an isopropyl alcohol solution, and then add 12 g of aluminum isopropoxide into the solution to obtain an aluminum isopropoxide precursor solution.

[0095] (2) place 1000 g of Fe-Cr-Si-B-C powder at the bottom of a reaction cavity, set the fluidized gas flow temperature to 80 DEG C, and then open a peristaltic pump and an atomizing nozzle to ensure continuous reaction.

[0096] (3) place the Fe-Cr-Si-B-C powder coated with the xerogel into a muffle furnace, calcine the Fe-Cr-Si-B-C powder at 500 DEG C under a nitrogen protective atmosphere for 1 h, and obtain coated powder.

[0097] (4) fully stir 100 g of the Fe-Cr-Si-B-C powder after modification and 2 g of a resin (20 ml of an acetone solvent) solution, sieve after the solvent is completely volatilized, and obtain Fe-Cr-Si-B-C alloy powder granules with a particle size interval of 40 mesh to 200 mesh.

[0098] (5) press the granulated powder under 2000 MPa to obtain a soft magnetic composite green body.

[0099] (6) anneal the green body under a nitrogen atmosphere at 500 DEG C for 1 h to obtain a soft magnetic composite sample.

[0100] Embodiment 7

[0101] The embodiment provides a high-efficiency chemical liquid phase coating method of a metal soft magnetic powder, which comprises the following steps:

[0102] (1) uniformly mix 38 mL of deionized water and 100 mL of an isopropyl alcohol solution, and then add 12 g of aluminum isopropoxide into the solution to obtain an aluminum isopropoxide precursor solution.

[0103] (2) place 1000 g of Fe-Cr-Si-B-C powder at the bottom of a reaction cavity, set the fluidized gas flow temperature to 80 DEG C, and then open a peristaltic pump and an atomizing nozzle to ensure continuous reaction.

[0104] (3) place the Fe-Cr-Si-B-C powder coated with the xerogel into a muffle furnace, calcine the Fe-Cr-Si-B-C powder at 500 DEG C under a nitrogen protective atmosphere for 1 h, and obtain coated powder.

[0105] (4) Take 100 g of Fe-Cr-Si-B-C powder after coating modification and 2 g of resin (20 ml of acetone solvent) solution, fully stir, sieve after the solvent volatilizes completely, to obtain Fe-Cr-Si-B-C alloy powder granulation, the particle size interval is 40 mesh~200 mesh.

[0106] (5) The granulation powder is pressed under 2000 MPa to obtain a soft magnetic composite material green body.

[0107] (6) The green body is annealed at 500 DEG C for 1 hour in a nitrogen atmosphere to obtain a soft magnetic composite material sample.

[0108] Example 8

[0109] The embodiment provides a high-efficiency chemical liquid phase coating method of a metal soft magnetic powder, which comprises the following steps:

[0110] (1) 80 mL of deionized water and 160 mL of ethanol solution are uniformly mixed, and 20 mL of tetraethyl orthosilicate is added to obtain a tetraethyl orthosilicate precursor solution.

[0111] (2) 2000 g of Fe-Si powder is placed at the bottom of a reaction cavity, a fluidized gas flow temperature of 80 DEG C is set, a peristaltic pump and an atomizing nozzle are started to ensure continuous reaction.

[0112] (3) The Fe-Si powder coated with the dry gel is placed in a muffle furnace, calcined at 500 DEG C for 1 h under a nitrogen protection atmosphere, and coated powder is obtained.

[0113] (4) Take 100 g of Fe-Si powder after coating modification and 2 g of resin (20 ml of acetone solvent) solution, fully stir, sieve after the solvent volatilizes completely, to obtain Fe-Cr-Si-B-C alloy powder granulation, the particle size interval is 40 mesh~200 mesh.

[0114] (5) The granulation powder is pressed under 2000 MPa to obtain a soft magnetic composite material green body.

[0115] (6) The green body is annealed at 700 DEG C for 1 hour in a nitrogen atmosphere to obtain a soft magnetic composite material sample.

[0116] Example 9

[0117] The embodiment provides a high-efficiency chemical liquid phase coating method of a metal soft magnetic powder, which comprises the following steps:

[0118] (1) 60 mL of deionized water and 200 mL of ethanol solution are uniformly mixed, and 40 g of magnesium acetate tetrahydrate is added to obtain a magnesium acetate tetrahydrate precursor solution.

[0119] (2) Take 2000g Fe-Si-Cr powder and place it at the bottom of the reaction chamber, set the fluidized gas flow temperature to 60°C, start the peristaltic pump and the atomizing nozzle to ensure continuous reaction.

[0120] (3) Place the dry gel coated Fe-Si-Cr powder in a muffle furnace and calcine it at 500°C for 1h under a nitrogen protective atmosphere to obtain the coated powder.

[0121] (4) Take 100g of the modified Fe-Si powder and 2g of the resin solution (20ml of acetone solvent) and stir thoroughly, then sieve after the solvent is completely volatilized to obtain Fe-Cr-Si-B-C alloy powder granules with a particle size range of 40-200 mesh.

[0122] (5) Press the granulated powder at 658MPa to obtain a soft magnetic composite green body.

[0123] (6) Solidify the green body at 150°C for 2 hours to obtain a soft magnetic composite sample.

[0124] Comparative Example 1

[0125] The embodiment provides a preparation method of the above metal soft magnetic composite material, which comprises the following steps:

[0126] (1) Take 0.6g of phosphoric acid in 20ml of ethanol, and ultrasonically disperse until completely dissolved to obtain a phosphoric acid passivation solution.

[0127] (2) Take 100g of Fe-Cr-Si-B-C amorphous soft magnetic powder and place it in the phosphoric acid passivation solution, and stir until completely dry under the condition of a 65°C water bath to obtain surface-coated modified Fe-Cr-Si-B-C amorphous soft magnetic powder.

[0128] (3) Take the modified Fe-Cr-Si-B-C amorphous soft magnetic powder and 2g of the resin solution (20ml of acetone solvent) and stir thoroughly, then sieve after the solvent is completely volatilized to obtain Fe-Cr-Si-B-C alloy powder granules with a particle size range of 40-200 mesh.

[0129] (4) Press the granulated powder at 600MPa to obtain a soft magnetic composite green body.

[0130] (5) Anneal the green body in an air atmosphere at 200°C for 1 hour to obtain a soft magnetic composite sample.

[0131] The schematic diagram of the coating equipment adopted by the present application is shown in Figure 1 , Figure 2 The SEM photos of the powder before and after coating in Example 1 are compared, Figure 3 The SEM photos of the powder after coating with different concentrations of precursors in Example 1 are compared,Figure 4 EDS photo of the powder coated with different concentrations of precursor for Example 1. Figure 5 The powder resistivity results of the metal soft magnetic powder prepared in Example 1 of the present application at different concentrations of precursor. Figure 6 The powder resistivity results of the carbonyl iron powder before and after coating prepared in Example 3 of the present application. Figure 7 The cross-section TEM photo of the coated metal soft magnetic powder prepared in Example 1 of the present application.

[0132] As shown in Fig. 1, the powder surface is coated with a layer of coating. Figure 2 As shown in Fig. 2, the powder surface is coated with a layer of coating. Figure 3 The results shown in Fig. 3 indicate that the coating layer on the powder surface gradually becomes obvious with the increase of the content of aluminum isopropyl alcohol. Figure 4 The Al and O elements on the powder surface in Fig. 4 indicate that the powder surface is uniformly coated with Al2O3. Figure 5 The resistivity results shown in Fig. 5 indicate the obvious improvement of the insulating property of the coated powder. The method is applied to the carbonyl iron powder, and the insulating property of the coated powder is also improved, as shown in Fig. 6. Figure 6 As shown in Fig. 7, the cross-section photo of the coating layer shows that the coating layer on the powder surface is complete and uniform, and the thickness is thin. Figure 7 As shown in Fig. 8, Example 8 gives the SEM photo of the coated powder prepared by using tetraethyl orthosilicate as the precursor. Figure 8 As shown in Fig. 9, Example 9 gives the SEM and EDS results of the coated powder prepared by using magnesium acetate tetrahydrate as the precursor, both of which show good coating effect. Figure 9

[0133] The effective permeability and DC bias performance of the samples of Example 1, 2, 4 and Comparative Example 1 of the present application are shown in Table 1; Table 2 gives the power loss (Pcv) of Example 1, 2, 4 and Comparative Example 1 of the present application. P cv It can be seen that the soft magnetic composite material samples prepared by the present application have relatively low loss characteristics.

[0134] Table 1 Effective permeability and DC bias performance of samples prepared by different processes

[0135]

[0136] Table 2 Power loss (Pcv) of samples prepared by different processes P cv : mW / cm 3

[0137]

[0138] ​​Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A highly efficient chemical liquid-phase coating method for soft magnetic metal powder, characterized in that, The method includes the following steps: The powder to be coated is placed in the reaction chamber, and a fluidizing gas source is introduced into the reaction chamber to make the powder uniformly fluidized in the reaction chamber; the temperature of the fluidizing gas source is 50℃~600℃, and the flow rate is 4m³ / s. 3 / min~50m 3 / min, the airflow velocity is 0.4m / s~10m / s; Metal or organic compounds are dissolved in a solvent to form a coating precursor solution. The precursor solution is sprayed into the reaction chamber and reacted fully with the powder to be coated to obtain surface-modified soft magnetic metal powder. Surface-modified soft magnetic metal powder is calcined to obtain core-shell structured coated magnetic powder. The coated magnetic powder is then mixed with a resin binder, granulated, and pressed to obtain a green body of soft magnetic metal composite material. The metal soft magnetic composite material is obtained by heat treatment of the green blank and then heat curing or annealing.

2. The method for efficient chemical liquid-phase coating of soft magnetic metal powder according to claim 1, characterized in that, The metal compounds include aluminum isopropoxide, boehmite white powder, aluminum sec-butoxide, magnesium acetate tetrahydrate, or sodium silicate nonahydrate; the organic compounds include tetraethyl orthosilicate or tetrabutyl titanate. Among them, aluminum isopropoxide, boehmite, and aluminum sec-butoxide have a purity greater than 99% and an aluminum content between 5% and 30%; tetraethyl orthosilicate, magnesium acetate tetrahydrate, and sodium silicate nonahydrate have a purity greater than 98%.

3. The method for efficient chemical liquid-phase coating of soft magnetic metal powder according to claim 1, characterized in that, The solvent includes single or mixed organic solvents such as deionized water, methanol, ethanol, glycerol, isopropanol, and toluene.

4. The efficient chemical liquid-phase coating method for soft magnetic metal powder according to claim 1, characterized in that, The soft magnetic metal powder includes at least one of carbonyl iron powder, Fe-Ni-Mo alloy powder, Fe-Ni alloy powder, Fe-Co alloy powder, Fe-Si alloy powder, Fe-Si-Al alloy powder, Fe-Si-Cr alloy powder, Fe-based amorphous alloy powder, Ni-based amorphous alloy powder, Co-based amorphous alloy powder, and Fe-based nanocrystalline powder.

5. The efficient chemical liquid-phase coating method for soft magnetic metal powder according to claim 1, characterized in that, The calcination temperature range is 400℃~1000℃, and the calcination time is 1h~3h.

6. The method for efficient chemical liquid-phase coating of soft magnetic metal powder according to claim 1, characterized in that, The coating precursor solution is drawn into the atomizing device by a suction device, and then forms a precursor solution spray after passing through the atomizing device.

7. The efficient chemical liquid-phase coating method for soft magnetic metal powder according to claim 6, characterized in that, The rotation speed of the suction device is 2 r / min to 100 r / min, and the air pressure of the atomizing device is 0.1 MPa to 10 MPa.

8. The application of the metal soft magnetic composite material prepared by the efficient chemical liquid phase coating method of metal soft magnetic powder according to any one of claims 1-7 in integrally molded inductors or metal soft magnetic powder cores.

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