Iron-based amorphous powder magnetic core and preparation method thereof

Abstract

The invention relates to a preparation method of an iron-based amorphous powder magnetic core. The powder magnetic core is formed by curing amorphous soft magnetic powder with the average particle diameter ranging from 10 micrometers to 50 micrometers and an insulating binding material, and is characterized in that the soft magnetic powder comprises Fe-based amorphous alloy, the components of the alloy can be expressed as Fe100-x-y-a-b-c-d Crx My Sia Bb Cc Pd Oe, in the formula, the element M is composed of at least one element of Ni, Co, Mo, Nb, Mn and V, x, y, a and b are equal to or larger than one, and c is equal to or larger than one. C and d respectively represent the weight percentages of the corresponding components, wherein 0.5 < = x < = 5, 0 < y < = 5, 0.1 < = a < = 10.6, 0.1 < = b < = 5.8, 0.1 < = c < = 1.6, 0.1 < = d < = 10, 0 < d < = 0.5, and 3 < = a + b + c + d + e < = 20. And the sintering temperature is below the amorphous crystallization temperature of 20 DEG C. The low iron loss of 100-350mW / cm < 3 > under the conditions of 100kHz and 100mT can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic materials, and in particular to an iron-based soft magnetic amorphous powder core and a preparation method thereof. Background Art

[0002] The pressed powder core is a soft magnetic composite material made by pressing the powder of magnetic material with an insulating coating. Due to its low loss, customizable shape and size, and relatively stable permeability with frequency, it is widely used in high-frequency applications such as switching power supplies, filters and DC-DC converters. Currently, the commonly used pressed powder cores include iron powder cores, iron silicon powder cores, sendust powder cores, permalloy powder cores, ferrite powder cores, etc. Amorphous powder cores have become a hot research topic in pressed powder cores due to their superior soft magnetic properties, higher thermal stability and lower loss.

[0003] Although amorphous pressed powder cores have many advantages in electronic devices, such as low loss, high saturation magnetic induction intensity and excellent temperature stability, they also face some key problems in practical applications. First, there are challenges in the preparation process of raw amorphous powder. Currently used are mainly amorphous materials with traditional compositions such as Fe-Si-B and Fe-Si-B-Cr. These materials will partially crystallize due to insufficient cooling speed during the powder preparation process. The occurrence of this partial crystallization leads to a decrease in the magnetic properties of the final core, which cannot fully meet the design requirements.

[0004] In addition, some powders prepared by amorphous strip crushing may also have a negative impact on the performance of the final product due to their sharp shape and poor fluidity. These powders may lead to uneven magnetic property distribution or structural instability during filling and molding. In addition, the manufacturing cost of amorphous powder cores is relatively high, which mainly stems from the complexity of their preparation process and the high cost of raw materials. Compared with traditional silicon steel and ferrite materials, amorphous powder cores are more expensive, which limits the possibility of their widespread application in some markets.

[0005] In summary, although amorphous powder cores have obvious advantages, the challenges they face in powder preparation and cost control still need further technological innovation and process optimization to solve. Summary of the invention

[0006] In view of the above problems, the present invention provides a soft magnetic iron-based amorphous alloy powder core which is low in price, has low coercive force, high saturation magnetic flux density, high effective magnetic permeability and low iron loss, and a preparation method thereof.

[0007] The technical solution adopted by the present invention to solve the above technical problems is: An amorphous alloy powder core is formed by solidifying soft magnetic powder and insulating adhesive material. The powder core is characterized in that the soft magnetic powder contains Fe-based amorphous alloy, and the composition of the alloy can be expressed as: Fe 100-x-y-a-b-c-d Cr x M y Si a B b C c P d O e , wherein the element M is composed of at least one element selected from Ni, Co, Mo, Nb, Mn and V, and x, y, a, b, c and d respectively represent the weight percentage content of each corresponding component, wherein 0.5≤x≤5, 0<y≤5, 0.1≤a≤10.6, 0.1≤b≤5.8, 0.1≤c≤1.6, 0.1≤d≤10, 0<d≤0.5 and satisfies 3≤a+b+c+d+e≤20.

[0008] On the other hand, a method for manufacturing a powder core is characterized in that the powder core is obtained by press-molding a composition containing the soft magnetic powder and an insulating binder to obtain a molded body and heating the obtained molded body. The preparation process includes at least the following steps: A mixing step of fully mixing the magnetic powder and the insulating adhesive material to obtain a mixture of the magnetic powder and the insulating adhesive material; A drying step, drying the mixture according to the characteristics of the insulating adhesive material; A molding step, wherein the dried mixed powder is pressed to obtain a molded body; The sintering step is to sinter the molded body to obtain a powder magnetic core with a certain strength.

[0009] Compared with the prior art, the amorphous alloy composition in the present invention cleverly improves the amorphous forming ability through the precise combination of metal and non-metal elements and the introduction of a small amount of oxygen. This innovative design can easily prepare amorphous powder with a high degree of sphericity, which is difficult to achieve in traditional processes. Through granulation and heat treatment processes, magnetic powder cores with excellent soft magnetic properties and high-frequency characteristics can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a DSC curve diagram of the alloy powder described in Example 1 of the present invention; Figure 2 The XRD spectrum of the alloy powder described in Example 1 of the present invention; Figure 3 This is a SEM scanning electron microscope image of the alloy powder described in Example 1 of the present invention.

[0011] Figure 4 This is the hysteresis loop diagram of the alloy powder described in Example 1 of the present invention. DETAILED DESCRIPTION

[0012] The technical solution will be further described below through the following specific embodiments: Example

[0013] This embodiment provides a method for preparing an iron-based amorphous pressed powder magnetic core, and the preparation process is as follows: Select the component as Fe 87.63 Cr 1.68 Mo 1.74 Si 5.66 B 1.31 C 0.17 P 1.75 O 0.06 The amorphous powder has a D50 of 8.1 μm and a D90 of 21.6 μm. The powder is surface treated, specifically, heat treated at 200°C for 2 hours in an argon atmosphere to remove adsorbents on the powder surface and reduce the internal stress of the amorphous powder.

[0014] The amorphous magnetic powder and the insulating silicone resin are mixed in a ratio of 98:2, and the obtained mixture is placed in a drying furnace and dried at 110 degrees for one hour to obtain a dried amorphous magnetic powder resin mixture. The above mixture is crushed and passed through a 40-mesh sieve to obtain granulated powder with a particle size of less than 380 μm.

[0015] At 20 ton / cm 2 The magnetic powder core is pressed into a ring shape under pressure, and the pressed magnetic powder core is placed in a vacuum furnace and kept at 395°C for 1 hour for heat treatment to fully solidify the insulating material.

[0016] The iron-based amorphous pressed powder core prepared by the above steps has excellent soft magnetic properties and high-frequency characteristics. Its saturation magnetic induction intensity B s The magnetic permeability is 47.9, and the iron loss is 213 W / cm at a frequency of 100kHz and a flux density of 100mT. 3 . This magnetic core can be widely used in various high-frequency transformers and inductors. Example

[0017] This embodiment provides a method for preparing an iron-based amorphous pressed powder magnetic core, and the preparation process is as follows: Select the component as Fe 89.2 Cr 1.9 Mn 0.5 Si 4.5 B 1.5 C0.3 P 2.0 O 0.1 The amorphous powder has a D50 of 12.5 μm and a D90 of 28.3 μm. The powder is surface treated, specifically, heat treated at 200°C for 2 hours in an argon atmosphere to remove adsorbents on the powder surface and reduce the internal stress of the amorphous powder.

[0018] The amorphous magnetic powder, silane coupling agent and silicone resin were mixed thoroughly and uniformly according to the ratio of 97.7:2.3, and the obtained mixture was placed in a drying furnace and dried at 110 degrees for one hour to obtain a dried amorphous magnetic powder resin mixture. The above mixture was crushed and passed through a 40-mesh sieve to obtain granulated powder with a particle size of less than 380 μm.

[0019] At 20 ton / cm 2 The magnetic powder core is pressed into a ring shape under pressure, and the pressed magnetic powder core is placed in a vacuum furnace and heat treated at 430°C for 1 hour to fully solidify the insulating material.

[0020] The iron-based amorphous pressed powder core prepared by the above steps has excellent soft magnetic properties and high-frequency characteristics, with a saturation magnetic induction intensity Bs of 1.52 T, a magnetic permeability of 47.9, and an iron loss of 347 W / cm3 at a frequency of 100 kHz and a magnetic flux density of 100 mT. The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0021] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A powder core, formed by curing soft magnetic powder and insulating adhesive material. The powder core is characterized in that the soft magnetic powder contains Fe-based amorphous alloy, and the composition of the alloy can be expressed as: Fe100-xyabc-dCrx My Sia Bb Cc Pd Oe, wherein the element M is composed of at least one element of Ni, Co, Mo, Nb, Mn and V, and x, y, a, b, c and d represent the weight percentage content of each corresponding component, wherein 0.5≤x≤5, 0<y≤5, 0.1≤a≤10.6, 0.1≤b≤5.8, 0.1≤c≤1.6, 0.1≤d≤10, 0<d≤0.5 and 3≤a+b+c+d+e≤20 is satisfied.

2. The soft magnetic powder according to claim 1, wherein the particle size is between 1 μm and 150 μm, and the average particle size is between 10 μm and 50 μm.

3. A method for manufacturing a powder magnetic core, characterized in that: The method is to press-form a composition containing the soft magnetic powder and an insulating binder material to obtain a molded body and then heat the obtained molded body. The preparation process includes at least the following steps: A mixing step of fully mixing the magnetic powder and the insulating adhesive material to obtain a mixture of the magnetic powder and the insulating adhesive material; A drying step, drying the mixture according to the characteristics of the insulating adhesive material; A molding step, wherein the dried mixed powder is pressed to obtain a molded body; The sintering step is to sinter the molded body to obtain a powder magnetic core with a certain strength. 4 . The powder magnetic core according to claim 3 , wherein the insulating binder material is an insulating resin material.

5. The insulating resin material according to claim 4, wherein the resin material contains at least one of epoxy resin, silicone resin, phenol resin, acrylic resin or polyamide resin.

6. The method for manufacturing a powder magnetic core according to claim 3, wherein: The pressure of the forming process is 500MPa-3000MPa.

7. The method for manufacturing a powder magnetic core according to claim 3, wherein: The sintering step includes a sintering treatment of heating in an oxidizing atmosphere.

8. The highest reaching temperature in the sintering process according to claim 3 and claim 7 is Ts, and the crystallization temperature of the amorphous powder according to claim 1 and claim 2 is Tx1. The Ts and Tx1 satisfy the following relationship: Ts <Tx1-20。 9. The sintering process according to claim 7 and claim 8, wherein the process time is 30 to 600 minutes.

10. The powder magnetic core according to claim 1, characterized in that Its low iron loss: at 100kHz, 100mT, the iron loss is 100~350mW / cm3.

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