Iron-silicon compacted magnetic core, method for preparing the same, and inductor

Abstract

This specification discloses an iron-silicon compressed powder core, a method for preparing the same, and an inductor. 【Solution means】The preparation method includes: step (1) of mixing an iron-silicon alloy magnetic powder and a surface treatment agent to obtain a surface-treated magnetic powder; step (2) of mixing an inactivator, a solvent, and the surface-treated magnetic powder described in step (1) to obtain an inactivated magnetic powder; step (3) of performing an organic insulation binding on the inactivated magnetic powder described in step (2) to obtain a bound magnetic powder; step (4) of mixing a release agent and the bound magnetic powder described in step (3) to obtain a mixed magnetic powder material; and step (5) of performing press molding and annealing treatment on the mixed magnetic powder material described in step (4) to obtain the iron-silicon compressed powder core. The iron-silicon compressed powder core obtained by the preparation method according to the present application improves the insulation effect, reduces the eddy current loss, and improves the problems that the loss of the compressed powder core increases after the temperature rises and the temperature rises too fast.

Description

Technical Field

[0001] Examples of the present application relate to the technical fields of soft magnetic alloy materials and powder metallurgy. For example, they relate to a method for preparing an iron-silicon compacted powder core, and particularly relate to an iron-silicon compacted powder core, a method for preparing the same, and an inductor.

Background Art

[0002] Alloy magnetic powders composed of two elements, iron and silicon, and compacted powder cores manufactured therefrom are widely applied in various aspects such as AC inductors, output inductors, photovoltaic power supply inverter inductors, and new energy charging stand boost inductors due to characteristics such as high DC superposition characteristics, no noise, and low cost. With the needs of rapid charging and the development of power electronics technology, the power density has increased rapidly, and higher requirements have been put forward for magnetic inductor elements. Especially due to the increase in load and the improvement of DC superposition, the iron-silicon core needs to withstand a larger current. When the core rapidly heats up due to a large current, the loss of iron-silicon further increases. Eventually, the core fails in such a cycle.

[0003] The main process of a metal soft compacted powder core is to mix metal powder and an insulating material to form a uniform and dense layer of insulating material on the powder surface, add lubricating powder after drying the powder, then form a product of a desired shape in the mold of a press, and finally heat-treat the product under certain atmosphere and temperature conditions to remove defects and excess non-magnetic substances in the product and obtain a product with good comprehensive performance. As can be seen from the above manufacturing process, the main factors affecting core loss and temperature characteristics are the iron-silicon magnetic powder and the insulating material used. The loss and temperature rise of the iron-silicon alloy are its characteristics, and the only way to change the temperature rise characteristics is to start from the insulating material.

[0004] CN112530656A discloses a method for preparing a low-loss iron-silicon powder core, comprising the steps of alloy melting, crushing, sieving, surface treatment, insulating coating, lubricant addition, press forming, heat treatment, and surface coating, wherein in the sieving process, the powder is blended in a mass ratio of -325 mesh:-250 mesh:-120 mesh = 2:3:1, and the surface of the powder core is coated after the heat treatment is completed. The main component of the low-loss iron-silicon powder core of this application is an iron-silicon binary alloy, with 0.22-0.25% chromium, 0.08-0.15% vanadium, and 6.7-7.0% silicon added, with the remainder being iron. The iron-silicon compacted magnetic core prepared in this invention can achieve a saturation magnetic flux density of 1.6T or higher, and has a volume specific loss Pcv of 125-135 mW / cm² at 50 kHz and 500 Gs. 3 The iron-silicon compacted magnetic core of this application can be made lower, and has the advantage of high saturation magnetic flux density and low loss.

[0005] CN113299451A discloses an iron-silicon compacted magnetic core coated with FeNi nanoparticles / epoxy resin composite, the preparation method of which includes a powder mixing step, a modification step, an insulating coating step, a baking step, a press molding step and a vacuum annealing step. The application describes an iron-silicon compacted magnetic core mainly composed of iron-silicon powder, with a single layer of FeNi nanoparticles / epoxy resin coating on the surface, which has advantages such as lower magnetic loss, higher permeability, higher product density, and lower cost compared to related products.

[0006] While all of the above technical proposals improve the low loss of compacted magnetic cores, CN112530656A has further shortcomings, such as high molding pressure and complex powder particle size grading, and does not adequately disclose the loss portion after the temperature rise of the magnetic core. Furthermore, the iron-silicon alloy milling uses trace elements such as precious metals like chromium and vanadium, increasing costs and failing to solve the technical problem of iron-silicon rusting, nor does it achieve the effect of reducing raw material costs. CN113299451A uses expensive nano-FeNi material, requires characteristic processes such as a vacuum environment for baking, and does not adequately explain the role of the FeNi material in the application. Moreover, the permeability of the samples in the examples does not improve significantly, and the loss of the compacted magnetic core in this application is higher than the industry standard, showing no clear advantage, and the rules governing the change in loss with increasing temperature of the magnetic core are not explained.

[0007] Therefore, how to improve the problem of increased core loss with rising temperature is an urgent issue that needs to be addressed in the fields of soft magnetic alloy materials and powder metallurgy. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The following is an overview of the subject matter described in detail in this paper. This overview does not limit the scope of the claims.

[0009] To solve the above technical problems, embodiments of the present invention provide an iron-silicon powder core, a method for preparing the same, and an inductor, which improve the heat dissipation performance of the powder core by enhancing the deactivation and insulation effects, and effectively solve the problem of high losses and rapid temperature rise in iron-silicon alloy powder cores. [Means for solving the problem]

[0010] In Embodiment 1, the embodiment of the present application is: Step (1) involves mixing iron-silicon alloy magnetic powder with a surface treatment agent to obtain surface-treated magnetic powder, Step (2) involves mixing an inactivating agent, a solvent, and the surface-treated magnetic powder described in step (1) to obtain an inactivating magnetic powder. Step (3) involves performing organic insulating bonding to the deactivating magnetic powder described in step (2) to obtain the bonded magnetic powder, Step (4) involves mixing the release agent with the binding magnetic powder described in step (3) to obtain a mixed magnetic powder material, Step (5) includes press molding and annealing of the mixed magnetic powder material described in step (4) to obtain the iron-silicon compacted magnetic core, This invention provides a method for preparing iron-silicon powder magnetic cores.

[0011] The preparation method described in this application enhances the deactivation and insulating effects, thereby changing the tendency of iron-silicon powder magnetic cores to experience increased losses after temperature rise, maintaining losses constant and even slightly reducing them, and overcoming the problem of increased losses due to temperature rise caused by increased superposition.

[0012] The iron-silicon alloy magnetic powder relating to this application is a typical iron-silicon alloy magnetic powder in the art, and is not specifically limited.

[0013] Preferably, the particle size range of the iron-silicon alloy magnetic powder described in step (1) is 15 to 150 μm, and may be, for example, 15 μm, 50 μm, 100 μm, 125 μm, or 150 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] Preferably, among the iron-silicon alloy magnetic powder described in step (1), the mass of particles with a particle size range of 75 to 150 μm accounts for 40 wt% or more of the total mass, for example, 40 wt%, 45 wt%, 50 wt%, 55 wt%, or 65 wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, of the iron-silicon alloy magnetic powder described in step (1), the mass of particles with a particle size range of 15 to 35 μm accounts for 30% or more of the total mass, and may be, for example, 30 wt%, 40 wt%, 45 wt%, 50 wt%, or 55 wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] The particle size range of the iron-silicon alloy magnetic powder according to this application increases the utilization rate of low-cost materials.

[0017] Preferably, the surface treatment agent described in step (1) comprises an organic aluminum aerosol.

[0018] The organic aluminum aerosol according to this application can effectively improve the surface condition of iron-silicon alloy magnetic powder and contribute to deactivation treatment.

[0019] Preferably, the mass of the surface treatment agent described in step (1) is 0.5 to 1.5 wt% of the iron-silicon alloy magnetic powder, for example, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, or 1.5 wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the mixture described in step (1) is further baked.

[0021] Preferably, the baking temperature is 75-85°C, and may be, for example, 75°C, 78°C, 80°C, 82°C, or 85°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the inactivator described in step (2) comprises a water-soluble inorganic material, and is preferably phosphoric acid and / or aluminum dihydrogen phosphate.

[0023] Preferably, the mass of the deactivator described in step (2) is 0.15 to 2.5 wt% of the iron-silicon alloy magnetic powder. For example, it may be 0.15 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 2 wt% or 2.5 wt%, but is not limited to the enumerated values, and other unenumerated values within the numerical range are equally applicable.

[0024] Preferably, the solvent described in step (2) contains deionized water.

[0025] Preferably, the mass of the solvent described in step (2) is 1.5 to 3 times that of the deactivator. For example, it may be 1.5 times, 1.8 times, 2 times, 2.5 times or 3 times, but is not limited to the enumerated values, and other unenumerated values within the numerical range are equally applicable.

[0026] Preferably, step (2) further includes drying after the mixing.

[0027] Preferably, before the organic insulation binding described in step (3), it further includes mixing a silane coupling agent with the deactivated magnetic powder described in step (2).

[0028] The silane coupling agent according to the present application is mixed with the deactivated magnetic powder before binding, increases the uniformity of the application of the binder to the surface of the magnetic powder, and contributes to enhancing the penetrability of the binder.

[0029] The silane coupling agent includes any one or a combination of at least two of vinyl silane, amino silane or methacryloxy silane. Typical combinations include a combination of vinyl silane and amino silane, a combination of amino silane and methacryloxy silane, a combination of vinyl silane and methacryloxy silane, or a combination of vinyl silane, amino silane and methacryloxy silane, but are not limited thereto.

[0030] The silane coupling agent according to this application can improve the dispersibility and adhesiveness of the filler in the resin, improve the compatibility between the inorganic filler and the resin, and enhance the mechanical properties, electrical properties, and weather resistance of the filler.

[0031] Preferably, the mass of the silane coupling agent is 0.15 to 0.5 wt% of the iron-silicon alloy magnetic powder, for example, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.4 wt%, or 0.5 wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the method of organic insulating bonding described in step (3) involves mixing the binder solution with the deactivating magnetic powder described in step (2), drying it, and sieving it.

[0033] Preferably, the binder solution contains a silicone resin.

[0034] Preferably, the silicone resin includes a high-temperature resistant silicone resin and / or a modified silicone resin, and is preferably a polymethyl silicone resin and / or a polysilane silicone resin.

[0035] The silicone resin according to this application can improve the insulating properties of the powder, improve the compatibility between the inorganic filler and the resin, improve powder moldability, and enhance properties such as density.

[0036] Preferably, the solvent in the binder solution contains acetone.

[0037] Preferably, the mass of the binder in the binder solution is 0.3 to 1.5 wt% of the iron-silicon alloy magnetic powder, for example, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, or 1.5 wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the mass of the solvent in the binder solution is 1 to 5 times the mass of the binder, for example, 1, 2, 3, 4, or 5 times, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the mesh count of the sieve is 80 to 200 meshes, and may be, for example, 80 meshes, 100 meshes, 150 meshes, 180 meshes, or 200 meshes, but is not limited to the listed numbers, and other unlisted numbers within the numerical range are also applicable.

[0040] Preferably, the release agent described in step (4) comprises zinc stearate.

[0041] Preferably, the mass of the release agent described in step (4) is 0.3 to 0.5 wt% of the iron-silicon alloy magnetic powder, for example, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, or 0.5 wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, the press forming pressure described in step (5) is 1500 to 1800 MPa, and may be, for example, 1500 MPa, 1550 MPa, 1600 MPa, 1700 MPa or 1800 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] Preferably, the maximum temperature for the annealing process described in step (5) is 680 to 730°C, and may be, for example, 680°C, 690°C, 700°C, 710°C, 720°C, or 730°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the holding time for the annealing process described in step (5) is 25 to 35 minutes, and may be, for example, 25 min, 28 min, 30 min, 32 min, or 35 min, but is not limited to the listed numbers, and other unlisted numbers within the numerical range are also applicable.

[0045] Preferably, the annealing treatment described in step (5) further includes cooling and painting of a paint coat layer.

[0046] Preferably, the coating material of the coating layer includes an epoxy resin.

[0047] As a preferred technical proposal for the preparation method according to Embodiment 1 of the present application, the preparation method is: A step (1) of mixing iron-silicon alloy magnetic powder and organic aluminum aerosol, baking at 75-85°C to obtain surface-treated magnetic powder, wherein the mass of the organic aluminum aerosol is 0.5-1.5 wt% of the iron-silicon alloy magnetic powder, Step (2) is a step of mixing an inactivating agent, deionized water, and the surface-treated magnetic powder described in step (1), and drying to obtain an inactivating magnetic powder, wherein the inactivating agent is 0.15 to 2.5 wt% of the iron-silicon alloy magnetic powder, the mass of the deionized water is 1.5 to 3 times that of the inactivating agent, and the inactivating agent is phosphoric acid and / or aluminum dihydrogen phosphate. Step (3) is a step in which a silane coupling agent in an amount of 0.15 to 0.5 wt% by mass of the iron-silicon alloy magnetic powder is mixed with the deactivated magnetic powder described in step (2), then mixed with a silicone resin-acetone solution, dried, and sieved through an 80 to 200 mesh to obtain a bound magnetic powder, wherein the mass of the silicone resin is 0.3 to 1.5 wt% of the iron-silicon alloy magnetic powder, and the mass of the acetone is 1 to 5 times that of the silicone resin. Step (4) involves mixing 0.3 to 0.5 wt% by mass of the iron-silicon alloy magnetic powder with the binding magnetic powder described in step (3) to obtain a mixed magnetic powder material. Step (5) includes press molding of the mixed magnetic powder material described in step (4) at a pressure of 1500 to 1800 MPa, followed by annealing at a maximum temperature of 680 to 730°C, with a holding time of 25 to 35 minutes, and after cooling, applying an epoxy resin coating layer to obtain the iron-silicon compacted magnetic core. Of the iron-silicon alloy magnetic powder described in step (1), the mass with a particle size range of 75 to 150 μm accounts for 40 wt% or more of the total mass, the mass with a particle size range of 15 to 35 μm accounts for 30% or more of the total mass, and the remaining particle size range is 35 to 75 μm.

[0048] In Embodiment 2, the embodiment of the present application is: Obtained by the preparation method described in Embodiment 1, We provide iron-silicon powder magnetic cores.

[0049] In Embodiment 3, the embodiment of the present application is: Contains the iron-silicon powder magnetic core described in Embodiment 2, Provide an inductor. [Effects of the Invention]

[0050] Compared to related technologies, the embodiments of this application have at least the following beneficial effects.

[0051] (1) The iron-silicon compacted magnetic core obtained by the preparation method according to the embodiment of the present invention has improved deactivation and insulation effects and reduced eddy current loss, thereby improving the problem that loss increases after the compacted magnetic core's temperature rises and that the temperature rise is too rapid.

[0052] (2) The preparation method according to the embodiment of the present application is simple in process, does not require high equipment, and reduces the cost of materials.

[0053] After reading and understanding the detailed explanation, other aspects can also be understood. [Modes for carrying out the invention]

[0054] For the sake of understanding this application, the present application lists the following embodiments. Those skilled in the art will understand that these embodiments are merely for the purpose of understanding this application and should not be considered as specific limitations of this application. [Examples]

[0055] This embodiment provides a method for preparing an iron-silicon compacted magnetic core, the preparation method comprising the following steps.

[0056] (1) Iron-silicon alloy magnetic powder (silicon content 5 wt%, the remainder being iron) was mixed with 1 wt% by mass of organic aluminum aerosol (Showwa JR14W, nanoaluminum aerosol) of the iron-silicon alloy magnetic powder, and the mixture was baked at 80°C to obtain surface-treated magnetic powder.

[0057] Of the iron-silicon alloy magnetic powder, the mass with a particle size range of 75 to 150 μm accounted for 40 wt% of the total mass, the mass with a particle size range of 15 to 35 μm accounted for 30% of the total mass, and the remaining particle size range was 35 to 75 μm.

[0058] (2) The phosphoric acid, deionized water, and the surface-treated magnetic powder described in step (1) were mixed and dried to obtain an inactivated magnetic powder.

[0059] The mass of the phosphoric acid was 1 wt% of the iron-silicon alloy magnetic powder, and the mass of the deionized water was twice that of the phosphoric acid.

[0060] (3) Adding 0.25 wt% by mass of the iron-silicon alloy magnetic powder to the deactivated magnetic powder described in step (2), the mixture was then mixed with a silicone resin (FJN-9802 high-temperature silicone from China)-acetone solution, dried, and sieved through a 100-mesh sieve to obtain the bound magnetic powder.

[0061] The mass of the silicone resin was 1 wt% of the iron-silicon alloy magnetic powder, and the mass of the acetone was three times that of the silicone resin.

[0062] (4) A mixed magnetic powder material was obtained by mixing 0.4 wt% by mass of the iron-silicon alloy magnetic powder with the binding magnetic powder described in step (3).

[0063] (5) The mixed magnetic powder material described in step (4) was press-molded at a pressure of 1700 MPa, then annealed at a maximum temperature of 700°C for a holding time of 30 min, and after cooling, an epoxy resin coating layer was applied to obtain the iron-silicon compacted magnetic core. [Examples]

[0064] This embodiment provides a method for preparing an iron-silicon compacted magnetic core, the preparation method comprising the following steps.

[0065] (1) Iron-silicon alloy magnetic powder (silicon content 4.5 wt%, the remainder being iron) was mixed with 0.5 wt% by mass of organic aluminum aerosol (Showwa JR14W, nanoaluminum aerosol) of the iron-silicon alloy magnetic powder, and the mixture was baked at 85°C to obtain surface-treated magnetic powder.

[0066] Of the iron-silicon alloy magnetic powder, the mass with a particle size range of 75 to 150 μm accounted for 45 wt% of the total mass, the mass with a particle size range of 15 to 35 μm accounted for 35% of the total mass, and the remaining particle size range was 35 to 75 μm.

[0067] (2) Aluminum dihydrogen phosphate, deionized water, and the surface-treated magnetic powder described in step (1) were mixed and dried to obtain inactivated magnetic powder.

[0068] The mass of the aluminum dihydrogen phosphate was 0.15 wt% of the iron-silicon alloy magnetic powder, and the mass of the deionized water was 1.5 times that of the aluminum dihydrogen phosphate.

[0069] (3) An aminosilane coupling agent in an amount of 0.15 wt% by mass of the iron-silicon alloy magnetic powder was added to the deactivated magnetic powder described in step (2), then mixed with a polymethyl silicone resin-acetone solution, dried, and sieved through an 80-mesh sieve to obtain the bound magnetic powder.

[0070] The mass of the polymethyl silicone resin was 0.3 wt% of the iron-silicon alloy magnetic powder, and the mass of the acetone was 1 times that of the polymethyl silicone resin.

[0071] (4) A mixed magnetic powder material was obtained by mixing 0.3 wt% by mass of zinc stearate from the iron-silicon alloy magnetic powder with the binding magnetic powder described in step (3).

[0072] (5) The mixed magnetic powder material described in step (4) was press-molded at a pressure of 1500 MPa, then annealed at a maximum temperature of 730°C for a holding time of 25 mins, and after cooling, an epoxy resin coating layer was applied to obtain the iron-silicon compacted magnetic core. [Examples]

[0073] This embodiment provides a method for preparing an iron-silicon compacted magnetic core, the preparation method comprising the following steps.

[0074] (1) Iron-silicon alloy magnetic powder (silicon content 6.5 wt%, the remainder being iron) was mixed with 1.5 wt% by mass of organic aluminum aerosol (Showwa JR14W, nanoaluminum aerosol) of the iron-silicon alloy magnetic powder, and the mixture was baked at 75°C to obtain surface-treated magnetic powder.

[0075] Of the iron-silicon alloy magnetic powder, the mass with a particle size range of 75 to 150 μm accounted for 42 wt% of the total mass, the mass with a particle size range of 15 to 35 μm accounted for 32% of the total mass, and the remaining particle size range was 35 to 75 μm.

[0076] (2) The phosphoric acid, deionized water, and the surface-treated magnetic powder described in step (1) were mixed and dried to obtain an inactivated magnetic powder.

[0077] The mass of the phosphoric acid was 2.5 wt% of the iron-silicon alloy magnetic powder, and the mass of the deionized water was three times that of the phosphoric acid.

[0078] (3) Adding 0.5 wt% by mass of the methacryloxysilane coupling agent to the deactivated magnetic powder described in step (2), the mixture was then mixed with the polysilane silicone resin-acetone solution, dried, and sieved through a 200-mesh sieve to obtain the bound magnetic powder.

[0079] The mass of the polysilane silicone resin was 1.5 wt% of the iron-silicon alloy magnetic powder, and the mass of the acetone was five times that of the silicone resin.

[0080] (4) A mixed magnetic powder material was obtained by mixing zinc stearate, which was 0.5 wt% by mass of the iron-silicon alloy magnetic powder, with the binding magnetic powder described in step (3).

[0081] (5) The mixed magnetic powder material described in step (4) was press-molded at a pressure of 1800 MPa, then annealed at a maximum temperature of 680°C for a holding time of 35 mins, and after cooling, an epoxy resin coating layer was applied to obtain the iron-silicon compacted magnetic core. [Examples]

[0082] This embodiment provides a method for preparing an iron-silicon compacted magnetic core, and the only difference from Example 1 is that, in step (1), of the iron-silicon alloy magnetic powder described, 30 wt% of the total mass had a particle size range of 75 to 150 μm, 30% of the total mass had a particle size range of 15 to 35 μm, and the remaining particle size range was 35 to 75 μm. [Examples]

[0083] This embodiment provides a method for preparing an iron-silicon compacted magnetic core, and the only difference from Example 1 is that, in step (1), of the iron-silicon alloy magnetic powder described, 40 wt% of the total mass had a particle size range of 75 to 150 μm, 20% of the total mass had a particle size range of 15 to 35 μm, and the remaining particle size range was 35 to 75 μm. [Examples]

[0084] This embodiment provides a method for preparing an iron-silicon powder magnetic core, the only difference from Example 1 being that the mass of the phosphoric acid in step (2) was 0.1 wt% of the iron-silicon alloy magnetic powder. [Examples]

[0085] This embodiment provides a method for preparing an iron-silicon powder magnetic core, the only difference from Example 1 being that the mass of the phosphoric acid in step (2) was 2.8 wt% of the iron-silicon alloy magnetic powder. [Examples]

[0086] This embodiment provides a method for preparing an iron-silicon compacted magnetic core, and the only difference from Example 1 is that in step (3), the silane coupling agent was not mixed before mixing with the silicone resin-acetone solution. [Examples]

[0087] This embodiment provides a method for preparing an iron-silicon compacted magnetic core, the only difference from Example 1 being that in step (3), the mass of the silane coupling agent was 0.1 wt% of the iron-silicon alloy magnetic powder. [Examples]

[0088] This embodiment provides a method for preparing an iron-silicon powder magnetic core, the only difference from Example 1 being that in step (3), the mass of the silane coupling agent was 0.7 wt% of the iron-silicon alloy magnetic powder. [Examples]

[0089] This embodiment provides a method for preparing an iron-silicon powder magnetic core, the only difference from Example 1 being that in step (3), the mass of the silicone resin was 0.2 wt% of the iron-silicon alloy magnetic powder. [Examples]

[0090] This embodiment provides a method for preparing an iron-silicon powder magnetic core, the only difference from Example 1 being that in step (3), the mass of the silicone resin was 1.8 wt% of the iron-silicon alloy magnetic powder.

[0091] [Comparative Example 1] This comparative example provides a method for preparing an iron-silicon compacted magnetic core, and the only difference from Example 1 is that the silicone resin in step (3) is replaced with an equal mass of glass powder (T800 glass powder from Anywhere Powder).

[0092] [Comparative Example 2] This comparative example provides a method for preparing an iron-silicon powder magnetic core, and the only difference from Example 1 is that the silicone resin in step (3) is replaced with an equal mass of silica.

[0093] The iron-silicon powdered magnetic core obtained as described above was tested. Inductance test conditions: 20 turns winding, frequency 100 kHz. Loss test conditions: 50kHz, load 100mT. Test temperatures: 25°C, 50°C, 100°C, 150°C. The winding consisted of 22 turns + 22 turns, with the input and output being the same winding. The test results are shown in Tables 1 and 2 below.

[0094] [Table 1]

[0095] [Table 2]

[0096] From Tables 1 and 2, the following conclusions can be drawn.

[0097] (1) As can be seen from Examples 1 to 3, the iron-silicon compacted magnetic core obtained by the preparation method of the present invention improves deactivation and insulation effects, reduces eddy current loss, and improves the problem that loss increases after the compacted magnetic core's temperature rises and that the temperature rise is too rapid.

[0098] (2) As can be seen from the comparison between Examples 4 and 5 and Example 1, when the particle size range of the iron-silicon alloy magnetic powder was changed to exceed the preferred range of the present invention, the loss of compacted magnetic cores increased and the quality deteriorated, and the amount of compacted magnetic cores in the 35-75 μm range increased and the preparation cost increased.

[0099] (3) As can be seen from the comparison between Examples 6 and 7 and Example 1, when the mass of the deactivator in step (2) was changed to exceed the preferred range of the present invention, the loss of the powdered magnetic core increased and the inductance and quality of the powdered magnetic core decreased.

[0100] (4) As can be seen from the comparison between Example 8 and Example 1, when the silane coupling agent was not added in step (3), the loss of the compacted magnetic core increased and the quality of the compacted magnetic core deteriorated.

[0101] (5) As can be seen from the comparison between Examples 9 and 10 and Example 1, when the mass of the silane coupling agent in step (3) was not within the preferred range of the present invention, the inductance and quality of the compacted magnetic core decreased and the loss of the compacted magnetic core increased.

[0102] (6) As can be seen from the comparison between Examples 11 and 12 and Example 1, when the mass of the silicone resin in step (3) was not within the preferred range of the present invention, the inductance and quality of the powdered magnetic core decreased and the loss of the powdered magnetic core increased.

[0103] (7) As can be seen from the comparison between Comparative Examples 1 and 2 and Example 1, when organic bonding is replaced with inorganic bonding in step (3), the inductance and quality of the compacted magnetic core decrease, and the problem of increased losses due to temperature rise of the compacted magnetic core cannot be solved.

[0104] In summary, the iron-silicon compacted magnetic core obtained by the preparation method of this application improves deactivation and insulation effects, reduces eddy current losses, and improves the problem of increased losses and excessively rapid temperature rise in the compacted magnetic core after temperature rise. Furthermore, the preparation method of this application is simple, does not require high equipment, and reduces material costs.

[0105] Although the present application has described a detailed process flow with respect to the above-described embodiments, the present application is not limited to the above-described detailed process flow; that is, the present application is not necessarily limited to the above-described detailed process flow. Those skilled in the art should understand that any improvements to the present application, equivalent substitutions and additions of auxiliary components to each raw material of the present product, selection of specific forms, etc., are all included within the scope of protection and disclosure of the present application.

Claims

1. Step (1) involves mixing iron-silicon alloy magnetic powder with a surface treatment agent to obtain surface-treated magnetic powder, Step (2) involves mixing an inactivating agent, a solvent, and the surface-treated magnetic powder described in step (1) to obtain an inactivating magnetic powder. Step (3) involves performing organic insulating bonding to the deactivating magnetic powder described in step (2) to obtain the bonded magnetic powder, Step (4) involves mixing the release agent with the binding magnetic powder described in step (3) to obtain a mixed magnetic powder material, Step (5) includes press molding and annealing of the mixed magnetic powder material described in step (4) to obtain the iron-silicon compacted magnetic core, The surface treatment agent described in step (1) contains an organic aluminum aerosol, The inactivator described in step (2) comprises phosphoric acid and / or aluminum dihydrogen phosphate. A method for preparing an iron-silicon powder magnetic core.

2. The particle size range of the iron-silicon alloy magnetic powder described in step (1) is 15 to 150 μm. The preparation method according to claim 1.

3. Of the iron-silicon alloy magnetic powder described in step (1), the mass of particles with a particle size range of 75 to 150 μm accounts for 40 wt% or more of the total mass. The preparation method according to claim 2.

4. Of the iron-silicon alloy magnetic powder described in step (1), the mass of particles with a particle size range of 15 to 35 μm accounts for 30% or more of the total mass. The preparation method according to claim 3.

5. The mass of the surface treatment agent described in step (1) is 0.5 to 1.5 wt% of the iron-silicon alloy magnetic powder. The preparation method according to claim 1.

6. The process further comprises baking after the mixing described in step (1), The baking temperature is 75 to 85°C. The preparation method according to claim 1.

7. The mass of the deactivator described in step (2) is 0.15 to 2.5 wt% of the iron-silicon alloy magnetic powder. The preparation method according to claim 1.

8. The solvent described in step (2) includes deionized water, The preparation method according to claim 1.

9. The mass of the solvent described in step (2) is 1.5 to 3 times the mass of the inactivator. The preparation method according to claim 1.

10. The process further comprises drying after the mixing described in step (2), The preparation method according to claim 1.

11. The further step includes mixing the silane coupling agent with the deactivated magnetic powder described in step (2) before the organic insulating bond described in step (3). The preparation method according to claim 1.

12. The mass of the silane coupling agent is 0.15 to 0.5 wt% of the iron-silicon alloy magnetic powder. The preparation method according to claim 11.

13. The method of organic insulating bonding described in step (3) is to mix the binder solution with the inactivating magnetic powder described in step (2), dry it, and sift it. The preparation method according to claim 1.

14. The binder in the binder solution comprises a silicone resin, The preparation method according to claim 13.

15. The solvent in the binder solution contains acetone, The preparation method according to claim 13.

16. The mass of the binder in the binder solution is 0.3 to 1.5 wt% of the iron-silicon alloy magnetic powder. The preparation method according to claim 13.

17. The mass of the solvent in the binder solution is 1 to 5 times the mass of the binder. The preparation method according to claim 13.

18. The release agent described in step (4) contains zinc stearate. The preparation method according to claim 1.

19. The mass of the release agent described in step (4) is 0.3 to 0.5 wt% of the iron-silicon alloy magnetic powder. The preparation method according to claim 1.

20. The press forming pressure described in step (5) is 1500 to 1800 MPa. The preparation method according to claim 1.

21. The maximum temperature of the annealing treatment described in step (5) is 680 to 730°C, The incubation time is 25-35 minutes. The preparation method according to claim 1.

22. The annealing process described in step (5) further includes cooling and painting of a paint coat layer. The preparation method according to claim 1.

23. The paint material of the paint coating layer includes an epoxy resin. The preparation method according to claim 22.

24. A step (1) of mixing iron-silicon alloy magnetic powder and organic aluminum aerosol, baking at 75 to 85°C to obtain surface-treated magnetic powder, wherein the mass of the organic aluminum aerosol is 0.5 to 1.5 wt% of the iron-silicon alloy magnetic powder, Step (2) is a step of mixing an inactivating agent, deionized water, and the surface-treated magnetic powder described in step (1), and drying to obtain an inactivating magnetic powder, wherein the inactivating agent is 0.15 to 2.5 wt% of the iron-silicon alloy magnetic powder, the mass of the deionized water is 1.5 to 3 times that of the inactivating agent, and the inactivating agent is phosphoric acid and / or aluminum dihydrogen phosphate. Step (3) is a step in which 0.15 to 0.5 wt% by mass of the iron-silicon alloy magnetic powder is mixed with the deactivated magnetic powder described in step (2), then mixed with a silicone resin-acetone solution, dried, and sieved through an 80 to 200 mesh to obtain a bound magnetic powder, wherein the mass of the silicone resin is 0.3 to 1.5 wt% of the iron-silicon alloy magnetic powder, and the mass of the acetone is 1 to 5 times that of the silicone resin, Step (4) involves mixing 0.3 to 0.5 wt% by mass of the iron-silicon alloy magnetic powder with the binding magnetic powder described in step (3) to obtain a mixed magnetic powder material. Step (5) includes press molding of the mixed magnetic powder material described in step (4) at a pressure of 1500 to 1800 MPa, followed by annealing at a maximum temperature of 680 to 730°C, with a holding time of 25 to 35 mins, and then applying an epoxy resin coating layer after cooling to obtain the iron-silicon compacted magnetic core. Of the iron-silicon alloy magnetic powder described in step (1), the mass with a particle size range of 75 to 150 μm accounts for 40 wt% or more of the total mass, the mass with a particle size range of 15 to 35 μm accounts for 30% or more of the total mass, and the remaining particle size range is 35 to 75 μm. The preparation method according to claim 1.

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