High-stability low-loss iron core and preparation method thereof

Abstract

The invention discloses a high-stability low-loss iron core and a preparation method thereof, and relates to the technical field of magnetic materials, and the preparation method comprises the following steps: adding iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy and copper powder into a container, carrying out electric arc melting, and after melting, carrying out spray casting and transverse magnetic annealing in sequence to obtain a heat-treated iron-based amorphous alloy strip; and uniformly coating the surface of the heat-treated iron-based amorphous alloy with an insulating binder, winding, shearing, drying and curing to obtain the iron core.

Description

Technical Field

[0001] This invention relates to the field of magnetic materials technology, specifically to a highly stable, low-loss iron core and its preparation method. Background Technology

[0002] In modern life, iron cores are widely used in electrical devices and power transformers, occupying an important position. Meanwhile, with the continuous development of electronic information technology, miniaturization of electronic devices has become a market trend. The widespread adoption of microelectronic devices has placed demands on iron core materials for smaller size, higher efficiency, and greater stability. However, in high-frequency applications, frequency and eddy current losses increase. Under alternating transverse magnetic fields, the iron core experiences magnetostriction, high stress sensitivity, and structural fatigue, reducing its stability and thus affecting the service life of the equipment.

[0003] Therefore, developing a highly stable and low-loss iron core is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a highly stable, low-loss iron core and its preparation method, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a highly stable, low-loss iron core includes the following steps: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy and copper powder to a container, and melt by electric arc. After melting, perform spray casting and transverse magnetic annealing in sequence to obtain heat-treated iron-based amorphous alloy strip. S2: A heat-treated iron-based amorphous alloy is uniformly coated with an insulating adhesive, wound and cut, and dried and cured to obtain an iron core.

[0006] Further, in step S1, the transverse magnetic annealing conditions are 490-580℃, holding for 120-360min, gradient cooling at 2-4℃ / min, and magnetization at 300-320℃, 400-430℃, 450-480℃ and 500-520℃ for 10-30min, with a magnetic field strength of 6000-8000A / m and the magnetic field direction parallel to the width of the iron-based amorphous alloy strip.

[0007] Further, in step S2, the preparation method of the insulating adhesive is as follows: add waterborne epoxy resin and wetting and dispersing agent to deionized water, stir and mix well, then add modified boron nitride, stir and mix well, add deionized water, stir, and obtain the insulating adhesive; In the preparation of the insulating adhesive, the mass ratio of waterborne epoxy resin, wetting and dispersing agent and modified boron nitride is (60-80):(1-3):(5-10).

[0008] Furthermore, the preparation method of the waterborne epoxy resin is as follows: the epoxy resin emulsion and the epoxy curing agent are stirred and mixed evenly, and then vacuum dried to obtain the waterborne epoxy resin. In the preparation of waterborne epoxy resin, the mass ratio of epoxy resin emulsion to epoxy curing agent is 1:(0.8-1); The wetting and dispersing agent is one or more of BYK-190, BYK-348, and BYK-340.

[0009] Furthermore, the preparation method of the epoxy resin emulsion is as follows: the emulsifier and epoxy resin are mixed, heated and stirred until homogeneous, deionized water is added, and stirred until homogeneous to obtain the epoxy resin emulsion; In the preparation of epoxy resin emulsion, the mass ratio of emulsifier to epoxy resin is (15-30):100.

[0010] Further, the preparation method of the emulsifier is as follows: after preheating the epoxy resin, place it in a container, add polyethylene glycol monomethyl ether, heat and stir to mix, add potassium persulfate, react at 140-180℃ for 2-4 hours, cool to room temperature, and obtain the emulsifier; In the preparation of the emulsifier, the mass ratio of epoxy resin, polyethylene glycol monomethyl ether and potassium persulfate is 1:(2-4):(0.01-0.03).

[0011] Further, the preparation method of the epoxy curing agent is as follows: epoxy resin is mixed with tetraethylenepentamine, heated at 80-100℃ for 2-4 hours, distilled under reduced pressure, n-butyl glycidyl ether is added for end-capping, and then glacial acetic acid is added for neutralization reaction to obtain epoxy curing agent; In the preparation of epoxy curing agent, the mass ratio of epoxy resin, tetraethylenepentamine, and n-butyl glycidyl ether is 1:(0.8-1):(0.05-0.15).

[0012] Further, the preparation process of the modified boron nitride is as follows: add nano boron nitride to an aqueous ethanol solution, heat and stir to mix, add γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 55-65℃ for 1-3h to obtain modified nano boron nitride. In the preparation of modified boron nitride, the mass ratio of nano boron nitride to γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 1:(0.08-0.12).

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses an iron-based amorphous alloy as the base material and employs electric arc melting to repeatedly melt metal powder, thereby improving the uniformity of the chemical composition of the master alloy ingot and reducing segregation, thus enhancing the mechanical properties and stability of the core. Simultaneously, transverse magnetic annealing is used to heat-treat the iron-based amorphous alloy strip. On one hand, gradient cooling fully releases the internal stress of the base material, resulting in uniform magnetic domain distribution and reducing hysteresis loss; on the other hand, magnetization during gradient cooling alters the soft magnetic properties of the base material, improving its anti-biasing ability and thus enhancing the stability of the core.

[0014] 2. This invention introduces waterborne epoxy resin into an insulating adhesive. First, epoxy resin is polymerized with polyethylene glycol monomethyl ether, introducing hydrophilic segments. This not only improves the stability of the insulating adhesive but also reduces the use of low-volatile organic solvents, aligning with environmental protection principles. Second, an epoxy resin curing agent is synthesized using tetraethylenepentamine and epoxy resin as raw materials, and then end-capped with n-butyl glycidyl ether to improve its compatibility with the epoxy resin emulsion, thereby enhancing the adhesion of the insulating adhesive and ultimately improving the stability of the iron core.

[0015] 3. This invention introduces modified boron nitride into the insulating adhesive. Boron nitride is modified with γ-(2,3-epoxypropoxy)propyltrimethoxysilane to improve its compatibility with water-based epoxy resins and promote the uniform dispersion of nano-boron nitride in the adhesive. Simultaneously, the excellent insulating and thermal conductivity of boron nitride effectively improves the insulation and heat resistance of the insulating adhesive, thereby enhancing the stability of the iron core and reducing core losses. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In the following examples, the CAS number of polyethylene glycol monomethyl ether is 9004-74-4; the CAS number of tetraethylenepentamine is 112-57-2; the CAS number of n-butyl glycidyl ether is 2426-08-6; the CAS number of γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 2530-83-8; the purity of iron powder, cobalt powder, silicon powder, boron powder, and copper powder is 99.99%; the epoxy resin is of type E-44; and the particle size of nano boron nitride is 50 nm.

[0018] Example 1: A method for preparing a high-stability, low-loss iron core: Step 1: Heat treatment of iron-based amorphous alloy: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy powder and copper powder to a container, and melt by electric arc. After melting twice, spray casting is carried out by single-roller spin quenching to obtain iron-based amorphous alloy strip. S2: Under a nitrogen atmosphere, the iron-based amorphous alloy was placed at 530℃ and held for 360 min. The temperature was then gradually reduced at a rate of 2℃ / min. Magnetization was applied at 520℃, 480℃, 430℃, and 320℃ for 10 min, respectively, with a transverse magnetic strength of 6000 A / m, to obtain the heat-treated iron-based amorphous alloy strip. Step 2: Preparation of insulating adhesive: S1: After preheating 10 parts of epoxy resin at 40°C, place it in a container, add 20 parts of polyethylene glycol monomethyl ether, heat to 80°C and stir to mix, add 0.1 parts of potassium persulfate, react at 140°C for 2 hours, cool to room temperature, and obtain the emulsifier. S2: Mix 1.5 parts of emulsifier with 10 parts of epoxy resin, stir at 40°C until homogeneous, add deionized water, stir until homogeneous, and obtain epoxy resin emulsion. S3: Mix 10 parts of epoxy resin with 8 parts of tetraethylenepentamine, heat at 80°C for 2 hours, distill under reduced pressure, add 0.5 parts of n-butyl glycidyl ether for end-capping, and then add glacial acetic acid for neutralization reaction to obtain epoxy curing agent; S4: Mix 10 parts of epoxy resin emulsion with 8 parts of epoxy curing agent, and then vacuum dry to obtain waterborne epoxy resin. S5: Add 1 part of nano boron nitride to an aqueous ethanol solution, heat and stir at 50°C until well mixed, add 0.08 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 55°C for 1 h to obtain modified nano boron nitride. S6: Add 60 parts of waterborne epoxy resin and 1 part of BYK-190 to deionized water, stir and mix well, then add 5 parts of modified boron nitride, stir and mix well, add deionized water, stir, and obtain insulating adhesive. Step 3: Preparing the iron core: An insulating adhesive is uniformly coated on the surface of a heat-treated iron-based amorphous alloy, which is then wound, cut, and dried and cured at 80°C to obtain an iron core.

[0019] Example 2: A method for preparing a high-stability, low-loss iron core: Step 1: Heat treatment of iron-based amorphous alloy: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy powder and copper powder to a container, and melt by electric arc. After melting three times, spray casting is carried out by single-roller spin quenching to obtain iron-based amorphous alloy strip. S2: Under a nitrogen atmosphere, the iron-based amorphous alloy was placed at 550℃ and held for 240 min. The temperature was then gradually reduced at a rate of 3℃ / min. Magnetization was applied at 510℃, 460℃, 420℃ and 310℃ for 20 min respectively, with a transverse magnetic strength of 7000 A / m, to obtain the heat-treated iron-based amorphous alloy strip. Step 2: Preparation of insulating adhesive: S1: After preheating 10 parts of epoxy resin at 40°C, place it in a container, add 20 parts of polyethylene glycol monomethyl ether, heat to 80°C and stir to mix, add 0.1 parts of potassium persulfate, react at 140°C for 2 hours, cool to room temperature, and obtain the emulsifier. S2: Mix 1.5 parts of emulsifier with 10 parts of epoxy resin, stir at 40°C until homogeneous, add deionized water, stir until homogeneous, and obtain epoxy resin emulsion. S3: Mix 10 parts of epoxy resin with 8 parts of tetraethylenepentamine, heat at 80°C for 2 hours, distill under reduced pressure, add 0.5 parts of n-butyl glycidyl ether for end-capping, and then add glacial acetic acid for neutralization reaction to obtain epoxy curing agent; S4: Mix 10 parts of epoxy resin emulsion with 8 parts of epoxy curing agent, and then vacuum dry to obtain waterborne epoxy resin. S5: Add 1 part of nano boron nitride to an aqueous ethanol solution, heat and stir at 50°C until well mixed, add 0.08 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 55°C for 1 h to obtain modified nano boron nitride. S6: Add 60 parts of waterborne epoxy resin and 1 part of BYK-190 to deionized water, stir and mix well, then add 5 parts of modified boron nitride, stir and mix well, add deionized water, stir, and obtain insulating adhesive. Step 3: Preparing the iron core: An insulating adhesive is uniformly coated on the surface of a heat-treated iron-based amorphous alloy, which is then wound, cut, and dried and cured at 80°C to obtain an iron core.

[0020] Example 3: A method for preparing a high-stability, low-loss iron core: Step 1: Heat treatment of iron-based amorphous alloy: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy powder and copper powder to a container, and melt by electric arc. After melting 4 times, spray casting is carried out by single-roller spin quenching to obtain iron-based amorphous alloy strip. S2: Under a nitrogen atmosphere, the iron-based amorphous alloy was placed at 580℃ and held for 120 min. The temperature was then gradually reduced at a rate of 4℃ / min. Magnetization was applied at 520℃, 480℃, 400℃ and 300℃ for 30 min respectively, with a transverse magnetic strength of 8000 A / m, to obtain the heat-treated iron-based amorphous alloy strip. Step 2: Preparation of insulating adhesive: S1: After preheating 10 parts of epoxy resin at 40°C, place it in a container, add 20 parts of polyethylene glycol monomethyl ether, heat to 80°C and stir to mix, add 0.1 parts of potassium persulfate, react at 140°C for 2 hours, cool to room temperature, and obtain the emulsifier. S2: Mix 1.5 parts of emulsifier with 10 parts of epoxy resin, stir at 40°C until homogeneous, add deionized water, stir until homogeneous, and obtain epoxy resin emulsion. S3: Mix 10 parts of epoxy resin with 8 parts of tetraethylenepentamine, heat at 80°C for 2 hours, distill under reduced pressure, add 0.5 parts of n-butyl glycidyl ether for end-capping, and then add glacial acetic acid for neutralization reaction to obtain epoxy curing agent; S4: Mix 10 parts of epoxy resin emulsion with 8 parts of epoxy curing agent, and then vacuum dry to obtain waterborne epoxy resin. S5: Add 1 part of nano boron nitride to an aqueous ethanol solution, heat and stir at 50°C until well mixed, add 0.08 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 55°C for 1 h to obtain modified nano boron nitride. S6: Add 60 parts of waterborne epoxy resin and 1 part of BYK-190 to deionized water, stir and mix well, then add 5 parts of modified boron nitride, stir and mix well, add deionized water, stir, and obtain insulating adhesive. Step 3: Preparing the iron core: An insulating adhesive is uniformly coated on the surface of a heat-treated iron-based amorphous alloy, which is then wound, cut, and dried and cured at 80°C to obtain an iron core.

[0021] Example 4: A method for preparing a high-stability, low-loss iron core: Step 1: Heat treatment of iron-based amorphous alloy: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy powder and copper powder to a container, and melt by electric arc. After melting 4 times, spray casting is carried out by single-roller spin quenching to obtain iron-based amorphous alloy strip. S2: Under a nitrogen atmosphere, the iron-based amorphous alloy was placed at 580℃ and held for 120 min. The temperature was then gradually reduced at a rate of 4℃ / min. Magnetization was applied at 520℃, 480℃, 400℃ and 300℃ for 30 min respectively, with a transverse magnetic strength of 8000 A / m, to obtain the heat-treated iron-based amorphous alloy strip. Step 2: Preparation of insulating adhesive: S1: After preheating 10 parts of epoxy resin at 40°C, place it in a container, add 30 parts of polyethylene glycol monomethyl ether, heat to 90°C and stir to mix, add 0.2 parts of potassium persulfate, react at 160°C for 3 hours, cool to room temperature, and obtain the emulsifier. S2: Mix 2.4 parts of emulsifier with 10 parts of epoxy resin, stir at 50°C until homogeneous, add deionized water, stir until homogeneous, and obtain epoxy resin emulsion. S3: Mix 10 parts of epoxy resin with 9 parts of tetraethylenepentamine, heat at 90°C for 3 hours, distill under reduced pressure, add 1 part of n-butyl glycidyl ether for end-capping, and then add glacial acetic acid for neutralization reaction to obtain epoxy curing agent. S4: Mix 10 parts of epoxy resin emulsion with 9 parts of epoxy curing agent, and then vacuum dry to obtain waterborne epoxy resin. S5: Add 1 part of nano boron nitride to an aqueous ethanol solution, heat and stir at 50°C until well mixed, add 0.08 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 55°C for 1 h to obtain modified nano boron nitride. S6: Add 60 parts of waterborne epoxy resin and 1 part of BYK-190 to deionized water, stir and mix well, then add 5 parts of modified boron nitride, stir and mix well, add deionized water, stir, and obtain insulating adhesive. Step 3: Preparing the iron core: An insulating adhesive is uniformly coated on the surface of a heat-treated iron-based amorphous alloy, which is then wound, cut, and dried and cured at 80°C to obtain an iron core.

[0022] Example 5: A method for preparing a high-stability, low-loss iron core: Step 1: Heat treatment of iron-based amorphous alloy: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy powder and copper powder to a container, and melt by electric arc. After melting 4 times, spray casting is carried out by single-roller spin quenching to obtain iron-based amorphous alloy strip. S2: Under a nitrogen atmosphere, the iron-based amorphous alloy was placed at 580℃ and held for 120 min. The temperature was then gradually reduced at a rate of 4℃ / min. Magnetization was applied at 520℃, 480℃, 400℃ and 300℃ for 30 min respectively, with a transverse magnetic strength of 8000 A / m, to obtain the heat-treated iron-based amorphous alloy strip. Step 2: Preparation of insulating adhesive: S1: After preheating 10 parts of epoxy resin at 40°C, place it in a container, add 40 parts of polyethylene glycol monomethyl ether, heat to 100°C and stir to mix, add 0.3 parts of potassium persulfate, react at 180°C for 4 hours, cool to room temperature, and obtain the emulsifier. S2: Mix 3 parts emulsifier with 10 parts epoxy resin, stir at 60°C until homogeneous, add deionized water, stir until homogeneous, and obtain epoxy resin emulsion. S3: Mix 10 parts of epoxy resin with 10 parts of tetraethylenepentamine, heat at 100°C for 4 hours, distill under reduced pressure, add 1.5 parts of n-butyl glycidyl ether for end-capping, and then add glacial acetic acid for neutralization reaction to obtain epoxy curing agent. S4: Mix 10 parts of epoxy resin emulsion with 10 parts of epoxy curing agent, and then vacuum dry to obtain waterborne epoxy resin. S5: Add 1 part of nano boron nitride to an aqueous ethanol solution, heat and stir at 50°C until well mixed, add 0.08 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 55°C for 1 h to obtain modified nano boron nitride. S6: Add 60 parts of waterborne epoxy resin and 1 part of BYK-190 to deionized water, stir and mix well, then add 5 parts of modified boron nitride, stir and mix well, add deionized water, stir, and obtain insulating adhesive. Step 3: Preparing the iron core: An insulating adhesive is uniformly coated on the surface of a heat-treated iron-based amorphous alloy, which is then wound, cut, and dried and cured at 80°C to obtain an iron core.

[0023] Example 6: A method for preparing a high-stability, low-loss iron core: Step 1: Heat treatment of iron-based amorphous alloy: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy powder and copper powder to a container, and melt by electric arc. After melting 4 times, spray casting is carried out by single-roller spin quenching to obtain iron-based amorphous alloy strip. S2: Under a nitrogen atmosphere, the iron-based amorphous alloy was placed at 580℃ and held for 120 min. The temperature was then gradually reduced at a rate of 4℃ / min. Magnetization was applied at 520℃, 480℃, 400℃ and 300℃ for 30 min respectively, with a transverse magnetic strength of 8000 A / m, to obtain the heat-treated iron-based amorphous alloy strip. Step 2: Preparation of insulating adhesive: S1: After preheating 10 parts of epoxy resin at 40°C, place it in a container, add 40 parts of polyethylene glycol monomethyl ether, heat to 100°C and stir to mix, add 0.3 parts of potassium persulfate, react at 180°C for 4 hours, cool to room temperature, and obtain the emulsifier. S2: Mix 3 parts emulsifier with 10 parts epoxy resin, stir at 60°C until homogeneous, add deionized water, stir until homogeneous, and obtain epoxy resin emulsion. S3: Mix 10 parts of epoxy resin with 10 parts of tetraethylenepentamine, heat at 100°C for 4 hours, distill under reduced pressure, add 1.5 parts of n-butyl glycidyl ether for end-capping, and then add glacial acetic acid for neutralization reaction to obtain epoxy curing agent. S4: Mix 10 parts of epoxy resin emulsion with 10 parts of epoxy curing agent, and then vacuum dry to obtain waterborne epoxy resin. S5: Add 1 part of nano boron nitride to an aqueous ethanol solution, heat and stir at 50°C until well mixed, add 0.1 part of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 65°C for 3 hours to obtain modified nano boron nitride. S6: Add 70 parts of waterborne epoxy resin and 2 parts of BYK-190 to deionized water, stir and mix well, then add 8 parts of modified boron nitride, stir and mix well, add deionized water, stir, and obtain insulating adhesive. Step 3: Preparing the iron core: An insulating adhesive is uniformly coated on the surface of a heat-treated iron-based amorphous alloy, which is then wound, cut, and dried and cured at 100°C to obtain an iron core.

[0024] Example 7: A method for preparing a high-stability, low-loss iron core: Step 1: Heat treatment of iron-based amorphous alloy: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy powder and copper powder to a container, and melt by electric arc. After melting 4 times, spray casting is carried out by single-roller spin quenching to obtain iron-based amorphous alloy strip. S2: Under a nitrogen atmosphere, the iron-based amorphous alloy was placed at 580℃ and held for 120 min. The temperature was then gradually reduced at a rate of 4℃ / min. Magnetization was applied at 520℃, 480℃, 400℃ and 300℃ for 30 min respectively, with a transverse magnetic strength of 8000 A / m, to obtain the heat-treated iron-based amorphous alloy strip. Step 2: Preparation of insulating adhesive: S1: After preheating 10 parts of epoxy resin at 40°C, place it in a container, add 40 parts of polyethylene glycol monomethyl ether, heat to 100°C and stir to mix, add 0.3 parts of potassium persulfate, react at 180°C for 4 hours, cool to room temperature, and obtain the emulsifier. S2: Mix 3 parts emulsifier with 10 parts epoxy resin, stir at 60°C until homogeneous, add deionized water, stir until homogeneous, and obtain epoxy resin emulsion. S3: Mix 10 parts of epoxy resin with 10 parts of tetraethylenepentamine, heat at 100°C for 4 hours, distill under reduced pressure, add 1.5 parts of n-butyl glycidyl ether for end-capping, and then add glacial acetic acid for neutralization reaction to obtain epoxy curing agent. S4: Mix 10 parts of epoxy resin emulsion with 10 parts of epoxy curing agent, and then vacuum dry to obtain waterborne epoxy resin. S5: Add 1 part of nano boron nitride to an aqueous ethanol solution, heat and stir at 50°C until well mixed, add 0.12 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 65°C for 3 hours to obtain modified nano boron nitride. S6: Add 80 parts of waterborne epoxy resin and 3 parts of BYK-190 to deionized water, stir and mix well, then add 10 parts of modified boron nitride, stir and mix well, add deionized water, stir, and obtain insulating adhesive. Step 3: Preparing the iron core: An insulating adhesive is uniformly coated on the surface of a heat-treated iron-based amorphous alloy, which is then wound, cut, and dried and cured at 120°C to obtain an iron core.

[0025] Comparative Example 1: A method for preparing a high-stability, low-loss iron core: Step 1: Heat treatment of iron-based amorphous alloy: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy powder and copper powder to a container, and melt by electric arc. After melting 4 times, spray casting is carried out by single-roller spin quenching to obtain iron-based amorphous alloy strip. S2: Under a nitrogen atmosphere, the iron-based amorphous alloy is placed at 580℃ and held for 120 min, and then cooled at a gradient of 4℃ / min to obtain heat-treated iron-based amorphous alloy strip. The remaining steps are the same as in Example 7.

[0026] Comparative Example 2: A method for preparing a high-stability, low-loss iron core: Step 2: Preparation of insulating binder: S1: Mix 10 parts of epoxy resin with 10 parts of tetraethylenepentamine, heat at 100°C for 4 hours, distill under reduced pressure, add 1.5 parts of n-butyl glycidyl ether for end-capping, and then add glacial acetic acid for neutralization reaction to obtain epoxy curing agent. S2: Add 1 part of nano boron nitride to an aqueous ethanol solution, heat and stir at 50°C until well mixed, add 0.12 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 65°C for 3 hours to obtain modified nano boron nitride. S3: Add 50 parts epoxy resin and 3 parts BYK-190 to deionized water, stir and mix well, then add 10 parts modified boron nitride and 30 parts epoxy curing agent, stir and mix well, add deionized water, stir, and obtain insulating adhesive. The remaining steps are the same as in Example 7.

[0027] Comparative Example 3: A method for preparing a high-stability, low-loss iron core: Step 2: Preparation of insulating binder: S1: After preheating 10 parts of epoxy resin at 40°C, place it in a container, add 40 parts of polyethylene glycol monomethyl ether, heat to 100°C and stir to mix, add 0.3 parts of potassium persulfate, react at 180°C for 4 hours, cool to room temperature, and obtain the emulsifier. S2: Mix 3 parts emulsifier with 10 parts epoxy resin, stir at 60°C until homogeneous, add deionized water, stir until homogeneous, and obtain epoxy resin emulsion. S3: Mix 10 parts of epoxy resin with 10 parts of tetraethylenepentamine, heat at 100°C for 4 hours, distill under reduced pressure, add 1.5 parts of n-butyl glycidyl ether for end-capping, and then add glacial acetic acid for neutralization reaction to obtain epoxy curing agent. S4: Mix 10 parts of epoxy resin emulsion with 10 parts of epoxy curing agent, and then vacuum dry to obtain waterborne epoxy resin. S5: Add 80 parts of waterborne epoxy resin and 3 parts of BYK-190 to deionized water, stir and mix well, then add 10 parts of boron nitride, stir and mix well, add deionized water, stir, and obtain insulating adhesive. The remaining steps are the same as in Example 7.

[0028] Testing: Take the iron core samples prepared in the above examples and comparative examples, and use this parameter and electrical parameter measuring instrument to test the iron core performance.

[0029] The experimental results are shown in Table 1 below.

[0030] Table 1 Core Performance Test Data

[0031] Conclusion: By optimizing the core manufacturing process and the insulating binder formulation, the core exhibits good stability and low loss.

[0032] In Comparative Example 1, ordinary annealing was used to heat-treat the iron-based amorphous alloy strip, which increased the magnetic loss of the iron core and reduced its stability.

[0033] In Comparative Example 2, water-based epoxy resin was not used as the matrix for the insulating adhesive, which reduced the stability of the insulating adhesive and thus affected the stability of the iron core.

[0034] In Comparative Example 3, boron nitride was not modified, which reduced its compatibility with water-based epoxy resin, making it prone to agglomeration. This affected the insulation and heat resistance of the insulating adhesive, thereby affecting the stability of the iron core and operating losses.

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a high-stability, low-loss iron core, characterized in that: Includes the following steps: S1: Add iron powder, cobalt powder, silicon powder, boron powder, iron-phosphorus alloy and copper powder to a container, and melt by electric arc. After melting, perform spray casting and transverse magnetic annealing in sequence to obtain heat-treated iron-based amorphous alloy strip. S2: A heat-treated iron-based amorphous alloy is uniformly coated with an insulating adhesive, wound and cut, and dried and cured to obtain an iron core.

2. The method for preparing a high-stability, low-loss iron core according to claim 1, characterized in that: In step S1, the transverse magnetic annealing conditions are 490-580℃, holding for 120-360min, gradient cooling at 2-4℃ / min, and magnetization at 300-320℃, 400-430℃, 450-480℃ and 500-520℃ for 10-30min, with a magnetic field strength of 6000-8000A / m and the magnetic field direction parallel to the width of the iron-based amorphous alloy strip.

3. The method for preparing a high-stability, low-loss iron core according to claim 1, characterized in that: In step S2, the preparation method of the insulating adhesive is as follows: add waterborne epoxy resin and wetting and dispersing agent to deionized water, stir and mix well, then add modified boron nitride, stir and mix well, add deionized water, stir, and obtain the insulating adhesive. In the preparation of the insulating adhesive, the mass ratio of waterborne epoxy resin, wetting and dispersing agent and modified boron nitride is (60-80):(1-3):(5-10).

4. The method for preparing a high-stability, low-loss iron core according to claim 3, characterized in that: The preparation method of the waterborne epoxy resin is as follows: the epoxy resin emulsion and epoxy curing agent are stirred and mixed, and then vacuum dried to obtain the waterborne epoxy resin. In the preparation of waterborne epoxy resin, the mass ratio of epoxy resin emulsion to epoxy curing agent is 1:(0.8-1); The wetting and dispersing agent is one or more of BYK-190, BYK-348, and BYK-340.

5. The method for preparing a high-stability, low-loss iron core according to claim 4, characterized in that: The preparation method of the epoxy resin emulsion is as follows: mix the emulsifier with the epoxy resin, heat and stir until homogeneous, add deionized water, stir until homogeneous, and obtain the epoxy resin emulsion. In the preparation of epoxy resin emulsion, the mass ratio of emulsifier to epoxy resin is (15-30):

100.

6. The method for preparing a high-stability, low-loss iron core according to claim 5, characterized in that: The preparation method of the emulsifier is as follows: After preheating the epoxy resin, place it in a container, add polyethylene glycol monomethyl ether, heat and stir to mix, add potassium persulfate, react at 140-180℃ for 2-4 hours, cool to room temperature, and obtain the emulsifier. In the preparation of the emulsifier, the mass ratio of epoxy resin, polyethylene glycol monomethyl ether and potassium persulfate is 1:(2-4):(0.01-0.03).

7. The method for preparing a high-stability, low-loss iron core according to claim 4, characterized in that: The preparation method of the epoxy curing agent is as follows: epoxy resin is mixed with tetraethylenepentamine, heated at 80-100℃ for 2-4 hours, distilled under reduced pressure, n-butyl glycidyl ether is added for end-capping, and then glacial acetic acid is added for neutralization reaction to obtain epoxy curing agent; In the preparation of epoxy curing agent, the mass ratio of epoxy resin, tetraethylenepentamine, and n-butyl glycidyl ether is 1:(0.8-1):(0.05-0.15).

8. The method for preparing a high-stability, low-loss iron core according to claim 3, characterized in that: The preparation process of the modified boron nitride is as follows: add nano boron nitride to an aqueous ethanol solution, heat and stir to mix, add γ-(2,3-epoxypropoxy)propyltrimethoxysilane, stir and react at 55-65℃ for 1-3h to obtain modified nano boron nitride. In the preparation of modified boron nitride, the mass ratio of nano boron nitride to γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 1:(0.08-0.12).

9. The iron core is prepared by the method for preparing a high-stability, low-loss iron core according to any one of claims 1-8.

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