High-insulation high-temperature-resistant moisture-sensitive granulation powder for integrated inductor and preparation method thereof

Abstract

The application discloses a high-insulation high-temperature-resistant moisture-sensitive granulation powder for integrated inductors and a preparation method thereof, and the core is a multi-layer gradient coating system of a magnetic powder core+modified inorganic insulation layer+organic binder layer. A dense insulation barrier is formed by the surface-modified high-insulation inorganic filler, and a high-temperature-resistant moisture-sensitive organic binder function gradient layer is used to realize the synergistic improvement of insulation, high-temperature resistance and moisture sensitivity. The pain points of insulation breakdown and moisture sensitivity failure of the existing granulation powder in an extreme environment are solved, and the high-end integrated inductors such as new energy vehicles and industrial frequency converters are applicable.

Description

Technical Field

[0001] This invention relates to the fields of magnetic materials, insulating functional materials and passive electronic components, specifically to a high-insulation, high-temperature moisture-sensitive granulated powder for integrated inductors and its preparation method. Background Technology

[0002] As power electronics technology advances towards high power, high integration, and adaptability to extreme environments, integrated inductors, as core passive electronic components, face multiple challenges, including high insulation requirements (resistance to high voltage breakdown), high temperature resistance requirements (adaptation to long-term operation above 150℃), and moisture sensitivity resistance requirements (resistance to high humidity environments of 85℃ / 85% RH). Existing technologies suffer from the following key limitations: the insulation performance of current high-temperature moisture-sensitive granulated powders relies entirely on the organic phase. Organic insulating coatings are prone to aging and degradation under long-term high temperatures, leading to a significant decrease in insulation resistance. Furthermore, while using inorganic coatings directly can improve insulation, the lack of synergistic design with high-temperature moisture-sensitive binders prevents the simultaneous achievement of high insulation and high-temperature moisture sensitivity resistance. If the interfacial bonding between the magnetic powder, inorganic layer, and organic layer is primarily physical, interlayer delamination can easily occur under high-temperature and humid cycling, leading to failure. Therefore, developing a granulated powder that achieves high insulation and temperature resistance through optimized inorganic component design, while simultaneously enhancing moisture sensitivity resistance and interfacial stability through synergistic organic binder systems, is crucial for overcoming the performance bottlenecks of integrated inductors in extreme environments. Summary of the Invention

[0003] The core innovation of this invention lies in constructing a multi-layer gradient coating system consisting of a magnetic powder core, a modified inorganic insulating layer, and an organic binder layer. Performance breakthroughs are achieved through the following synergistic mechanisms: Modified inorganic insulating layer: High-insulation, high-temperature-resistant inorganic materials are selected and surface-modified to form a dense physical barrier, blocking electron migration and improving overall thermal stability; Organic binder layer: Based on rigid phenolic epoxy resin, a composite of silicon-modified multifunctional epoxy resin and organosilicon resin is formed. Under the action of a catalytic curing agent, a hydrophobic, highly cross-linked three-dimensional network is formed, ensuring the bonding strength between magnetic powder particles and forming a chemical bond with the inorganic insulating layer, exhibiting a highly cross-linked / highly hydrophobic functional gradient from the inside out; Surface modifier: Inorganic fillers are modified using silane coupling agents to prevent agglomeration and enhance the synergistic effect between coating layers.

[0004] Unless otherwise specified, the weight percentage of each component in this scheme refers to its percentage content relative to the weight of the magnetic powder.

[0005] S1. Magnetic Powder Pretreatment Place the passivated magnetic powder in an oven and bake at 60℃~180℃ for 1~3 hours, then cool to room temperature for later use.

[0006] S2. Surface modification of inorganic fillers Add 0.1–20 wt.% of inorganic filler to 3 wt.%–10 wt.% ethanol and stir for 0.5–2 h (stirring speed 30–250 rpm) until the system is homogeneous; add 0.1 wt.%–3 wt.% of surface modifier (silane coupling agent) and mechanically stir at 25–60 °C for 0.5–2 h (stirring speed 20–60 rpm) to allow the modifier molecules to be grafted onto the surface of the inorganic filler via hydroxyl reaction. Then dry at 60 °C–180 °C for 1–3 h and grind through a 40–200 mesh sieve to obtain the modified inorganic filler.

[0007] S3. Preparation of modified inorganic insulating gradient layer Modified inorganic filler was added to a solvent (butanone + ethylene glycol methyl ether, mass ratio 1:1) at 3 wt.% to 8 wt.% and stirred for 0.5 h to 2 h (stirring speed 30 to 250 rpm) until a stable suspension was formed. Pretreated magnetic powder was added and mechanically stirred at 25 to 80 ℃ for 0.5 to 2 h. By controlling the stirring speed (20 rpm to 60 rpm) and the solvent evaporation rate, the modified inorganic filler was uniformly adsorbed onto the surface of the magnetic powder, forming an insulating layer with gradually optimized density from the inside out. Subsequently, it was dried at 60 ℃ to 180 ℃ for 1 h to 3 h and then crushed and sieved through a granulator to a mesh size of 40 to 200 to obtain inorganic coated magnetic powder.

[0008] S4. Preparation of Organic Binder Layer Solution In a specific ratio, 0.5–5 wt.% of phenolic epoxy resin, 0.3–3 wt.% of modified epoxy resin, and 0.2–2 wt.% of silicone resin are added to 3–8 wt.% of solvent (butanone + ethanol, mass ratio 9:1). The mixture is stirred at 25–60°C for 0.5–2 h (stirring speed 30–250 rpm) until the solution is clear and transparent. Then, 0.05 wt.%–3 wt.% of curing agent is added, and stirring is continued for 0.5–1 h to obtain a uniform organic adhesive functional layer solution.

[0009] ; S5. Organic adhesive functional gradient layer coating The organic binder functional layer solution is slowly added to the inorganic coated magnetic powder, and mechanically stirred at 25~80℃ for 0.5~2h at a stirring speed of 20~60 rpm, so that the organic binder coats the surface of the inorganic insulating layer, and finally forms a multi-layer gradient coating system of magnetic powder core + modified inorganic insulating layer + organic binder layer.

[0010] S6. Granulation and Post-processing The composite coated magnetic powder was granulated to 40-100 mesh using a granulator, and then dried in an oven at 40-80℃ for 0.5-5 h to completely remove the solvent. After cooling to room temperature, it was crushed and sieved to 40-100 mesh using a granulator to ensure particle uniformity. Finally, 0.01-0.5 wt.% of release agent was added, and the mixture was mechanically stirred for 0.5-2 h at a stirring speed of 20-60 rpm until it was uniformly mixed to obtain a highly insulating, high-temperature, moisture-sensitive granulated powder.

[0011] Furthermore, the magnetic powder is any one or more composite magnetic powders selected from alloy powder, carbonyl iron powder, nanocrystalline magnetic powder, and amorphous magnetic powder, with a particle size of 5 μm to 50 μm. Furthermore, the inorganic filler is one or more of nano-alumina, aluminum nitride, silicon dioxide, and silicon carbide; the surface modifier is one or more of triethoxy(3-epoxypropyloxypropyl)silane, 3-aminopropyltriethoxysilane, propylisocyanatetriethoxysilane, ureapropyltriethoxysilane, n-octyltriethoxysilane, (epoxypropyloxy)propyltrimethoxysilane, (methacryloyloxy)propyltriethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0012] Furthermore, the phenolic epoxy resin is any one or a combination of two or more of the following: phenolic epoxy resin, o-cresol phenolic epoxy resin, aralkyl phenolic epoxy resin, biphenyl phenol type epoxy resin, dicyclopentadiene type phenolic epoxy resin, naphthalene type epoxy resin, trifunctional phenolic epoxy resin, and bisphenol A type phenolic epoxy resin; the modified epoxy resin is any one or a combination of two of the following: silicone resin modified epoxy resin and silane modified epoxy resin; the silicone resin is any one or a combination of two of the following: methyl silicone resin, methylphenyl silicone resin, and phenyl silicone resin; and the curing agent is any one or a combination of two of the following: 2-butylimidazole, 2-ethyl-4-methylimidazole, 2-ethylimidazole, 2-methylimidazole, 2-phenylimidazole, and 1-benzylimidazole.

[0013] Furthermore, the solvent is any one or a combination of two of ethanol, propanol, butanol, pentanol, acetone, butanone, pentanone, ethyl acetate, butyl acetate, ethylene glycol methyl ether, and dimethylformamide. Furthermore, the release agent is any one or a combination of two of stearate metal salts and polyether compounds; The granulated powder provided by this invention, through the synergistic effect of inorganic filler composite coating and high-performance organic binder, is a granulated powder for integrated inductors with high insulation, high temperature resistance and moisture resistance, and its preparation method is suitable for the manufacturing of integrated inductors under extreme working conditions (high temperature, high humidity, high voltage) such as new energy vehicles, industrial frequency converters, and high temperature environment sensors. Detailed Implementation

[0014] Example 1 The passivated alloy powder was placed in an oven and baked at 60°C for 1 h, then cooled to room temperature for later use. 0.1 wt.% of the inorganic filler was added to 10 wt.% of ethanol and stirred for 0.5 h (stirring speed 250 rpm) until the system was homogeneous. 0.1 wt.% of (methacryloyloxy)propyltriethoxysilane was added, and the mixture was mechanically stirred at 25°C for 0.5 h (stirring speed 60 rpm) to allow the modifier molecules to be grafted onto the surface of the inorganic filler via a hydroxyl reaction. The mixture was then dried at 120°C for 2 h and ground through a 40-mesh sieve to obtain the modified inorganic filler. The modified inorganic filler was added to 8 wt.% of a mixed solvent (acetone + ethylene glycol methyl ether, mass ratio 8:2) and stirred for 0.5 h (stirring speed 250 rpm) until a stable suspension was formed. The pretreated magnetic powder was added and mechanically stirred at 25 ℃ for 0.5 h. By controlling the stirring speed (60 rpm) and the solvent evaporation rate, the modified inorganic filler was uniformly adsorbed onto the surface of the magnetic powder, forming an insulating layer with gradually optimized density from the inside out. Subsequently, it was dried at 100 ℃ for 2 h and then crushed and sieved through a 40-mesh granulator to obtain inorganic coated magnetic powder. 2.5 wt.% of aralkylphenol epoxy resin, 1 wt.% of silicone-modified epoxy resin, and 0.7 wt.% of methylphenyl silicone resin were sequentially added to 8 wt.% of a mixed solvent (acetone + ethanol, mass ratio 9.5:0.5). The mixture was stirred at 25 ℃ to 60 ℃ for 0.5 h to 2 h (stirring speed 30 rpm to 250 rpm) until the solution became clear and transparent. Then, 0.15 wt.% of 2-butylimidazole was added, and stirring was continued for another 0.5 h to 1 h to obtain a homogeneous organic adhesive functional layer solution. The organic adhesive layer solution was slowly added to the inorganic coated magnetic powder, and the mixture was mechanically stirred at 25 ℃ for 0.5 h at a stirring speed of 60 rpm to coat the surface of the inorganic insulating layer with the organic adhesive, ultimately forming a multi-layer gradient coating system consisting of a magnetic powder core, a modified inorganic insulating layer, and an organic adhesive layer. The composite coated magnetic powder was granulated to 40 mesh using a granulator and dried in an oven at 50 ℃ for 2 h to completely remove the solvent. After cooling to room temperature, it was crushed and sieved to 40 mesh using a granulator to ensure particle uniformity. Finally, 0.2 wt.% calcium stearate was added and mechanically stirred for 0.5 h at a stirring speed of 30 rpm until the mixture was uniform, resulting in a highly insulating, high-temperature, moisture-sensitive granulated powder.

[0015] Example 2 The passivated alloy powder was placed in an oven and baked at 60 °C for 1 h, then cooled to room temperature for later use. 5 wt.% of the inorganic filler was added to 10 wt.% of ethanol and stirred for 0.5 h (stirring speed 250 rpm) until the system was homogeneous. 0.5 wt.% of (epoxypropyloxy)propyltrimethoxysilane was added, and the mixture was mechanically stirred at 25 °C for 0.5 h (stirring speed 60 rpm) to allow the modifier molecules to be grafted onto the surface of the inorganic filler via a hydroxyl reaction. The mixture was then dried at 120 °C for 2 h and ground through a 40-mesh sieve to obtain the modified inorganic filler. The modified inorganic filler was added to 8 wt.% of a mixed solvent (acetone + ethylene glycol methyl ether, mass ratio 8:2) and stirred for 0.5 h (stirring speed 250 rpm) until a stable suspension was formed. The pretreated magnetic powder was added and mechanically stirred at 25 ℃ for 0.5 h. By controlling the stirring speed (60 rpm) and the solvent evaporation rate, the modified inorganic filler was uniformly adsorbed onto the surface of the magnetic powder, forming an insulating layer with gradually optimized density from the inside out. Subsequently, it was dried at 100 ℃ for 2 h and then crushed and sieved through a 40-mesh granulator to obtain inorganic coated magnetic powder. 1.5 wt.% of aralkylphenol epoxy resin, 0.5 wt.% of silicone-modified epoxy resin, and 0.6 wt.% of methylphenyl silicone resin were added sequentially to 8 wt.% of a mixed solvent (acetone + ethanol, mass ratio 9:1). The mixture was stirred at 25 ℃ to 60 ℃ for 0.5 h to 2 h (stirring speed 30 rpm to 250 rpm) until the solution became clear and transparent. Then, 0.15 wt.% of 2-butylimidazole was added, and stirring was continued for another 0.5 h to 1 h to obtain a homogeneous organic adhesive functional layer solution. The organic adhesive layer solution was slowly added to the inorganic coated magnetic powder, and the mixture was mechanically stirred at 25 ℃ for 0.5 h at a stirring speed of 60 rpm to coat the surface of the inorganic insulating layer with the organic adhesive, ultimately forming a multi-layer gradient coating system consisting of a magnetic powder core, a modified inorganic insulating layer, and an organic adhesive layer. The composite coated magnetic powder was granulated to 40 mesh using a granulator and dried in an oven at 50 ℃ for 2 h to completely remove the solvent. After cooling to room temperature, it was crushed and sieved to 40 mesh using a granulator to ensure particle uniformity. Finally, 0.2 wt.% calcium stearate was added and mechanically stirred for 0.5 h at a stirring speed of 30 rpm until the mixture was uniform, resulting in a highly insulating, high-temperature, moisture-sensitive granulated powder.

[0016] Example 3 The passivated alloy powder was placed in an oven and baked at 60 °C for 1 h, then cooled to room temperature for later use. 5 wt.% of the inorganic filler was added to 10 wt.% of ethanol and stirred for 0.5 h (stirring speed 250 rpm) until the system was homogeneous. 0.5 wt.% of (epoxypropyloxy)propyltrimethoxysilane was added, and the mixture was mechanically stirred at 25 °C for 0.5 h (stirring speed 60 rpm) to allow the modifier molecules to be grafted onto the surface of the inorganic filler via a hydroxyl reaction. The mixture was then dried at 100 °C for 2 h and ground through a 40-mesh sieve to obtain the modified inorganic filler. The modified inorganic filler was added to 8 wt.% of a mixed solvent (acetone + ethanol, mass ratio 8:2) and stirred for 0.5 h (stirring speed 250 rpm) until a stable suspension was formed. The pretreated magnetic powder was added and mechanically stirred at 25 ℃ for 0.5 h. By controlling the stirring speed (60 rpm) and the solvent evaporation rate, the modified inorganic filler was uniformly adsorbed onto the surface of the magnetic powder, forming an insulating layer with gradually optimized density from the inside out. Subsequently, it was dried at 100 ℃ for 2 h and then crushed and sieved through a 40-mesh granulator to obtain inorganic coated magnetic powder. 2.5 wt.% of aralkylphenol epoxy resin, 1 wt.% of silicone-modified epoxy resin, and 0.7 wt.% of methylphenyl silicone resin were sequentially added to 8 wt.% of a mixed solvent (acetone + ethanol, mass ratio 9.5:0.5). The mixture was stirred at 25 ℃ to 60 ℃ for 0.5 h to 2 h (stirring speed 30 rpm to 250 rpm) until the solution became clear and transparent. Then, 0.15 wt.% of 2-butylimidazole was added, and stirring was continued for another 0.5 h to 1 h to obtain a homogeneous organic adhesive functional layer solution. The organic adhesive layer solution was slowly added to the inorganic coated magnetic powder, and the mixture was mechanically stirred at 25 ℃ for 0.5 h at a stirring speed of 60 rpm to coat the surface of the inorganic insulating layer with the organic adhesive, ultimately forming a multi-layer gradient coating system consisting of a magnetic powder core, a modified inorganic insulating layer, and an organic adhesive layer. The composite coated magnetic powder was granulated to 40 mesh using a granulator and dried in an oven at 50 ℃ for 2 h to completely remove the solvent. After cooling to room temperature, it was crushed and sieved to 40 mesh using a granulator to ensure particle uniformity. Finally, 0.2 wt.% calcium stearate was added and mechanically stirred for 0.5 h at a stirring speed of 30 rpm until the mixture was uniform, resulting in a highly insulating, high-temperature, moisture-sensitive granulated powder.

[0017] Table 1 Magnetic Ring Data

Claims

1. A method for preparing high-insulation, high-temperature moisture-sensitive granulated powder for integrated inductors, characterized in that, The preparation method includes the following steps: S1. Magnetic Powder Pretreatment Place the passivated magnetic powder in an oven and bake at 60~180℃ for 1~3 hours, then cool to room temperature for later use. S2. Surface modification of inorganic fillers Add 0.1~20 wt.% of inorganic filler to 3~10 wt.% ethanol and stir until the system is homogeneous; Add 0.1~3 wt.% of surface modifier, stir at 25~60℃ to allow the modifier molecules to be grafted onto the surface of the inorganic filler through hydroxyl reaction, then dry at 60~180℃, grind through a 40~200 mesh sieve to obtain the modified inorganic filler; S3. Preparation of modified inorganic insulating gradient layer The modified inorganic filler was added to 3-8 wt.% of solvent and stirred to form a stable suspension; Add the pretreated magnetic powder and mechanically stir at 25~80℃. By controlling the stirring speed and solvent evaporation rate, the modified inorganic filler is uniformly adsorbed on the surface of the magnetic powder to form an insulating layer. Then it is dried at 60~180℃, and then crushed and sieved through a 40~200 mesh to obtain inorganic coated magnetic powder; S4. Preparation of Organic Binder Layer Solution Add 0.5~5 wt.% phenolic epoxy resin, 0.3~3 wt.% modified epoxy resin, and 0.2~2 wt.% organosilicon resin to 3~8 wt.% solvent, stir at 25~60℃ until the solution is clear and transparent, add 0.05~3 wt.% curing agent, and continue stirring to obtain a uniform organic adhesive functional layer solution. S5. Organic adhesive functional layer coating The organic adhesive functional layer solution is slowly added to the inorganic coated magnetic powder and stirred at 25~80℃ to coat the surface of the inorganic insulating layer with the organic adhesive, thus forming a multi-layer gradient coating system. S6. Granulation and Post-processing The coated magnetic powder is granulated to 40-100 mesh and then dried in an oven at 40-80℃ to remove the solvent. After cooling to room temperature, crush and sieve through a 40-100 mesh screen; Finally, add 0.01~0.5 wt.% of release agent and stir until the mixture is uniform to obtain granulated powder.

2. The method for preparing the high-insulation, high-temperature moisture-sensitive granulated powder for inductors as described in claim 1, characterized in that, The magnetic powder is one or more of carbonyl iron powder, nanocrystalline magnetic powder, and amorphous magnetic powder, and the particle size of the magnetic powder is 5~50μm.

3. The method for preparing the high-insulation, high-temperature moisture-sensitive granulated powder for inductors as described in claim 1, characterized in that, The inorganic filler is a composite of one or more of nano-alumina, aluminum nitride, silicon dioxide, and silicon carbide; The surface modifier is one or more of the following: triethoxy(3-epoxypropyloxypropyl)silane, 3-aminopropyltriethoxysilane, propyltriethoxyisocyanate, ureapropyltriethoxysilane, n-octyltriethoxysilane, (epoxypropyloxy)propyltrimethoxysilane, (methacryloyloxy)propyltriethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

4. The method for preparing the high-insulation, high-temperature moisture-sensitive granulated powder for inductors as described in claim 1, characterized in that, The phenolic epoxy resin is one or more of the following: phenolic epoxy resin, o-cresol epoxy resin, aralkyl phenolic epoxy resin, biphenyl phenol type epoxy resin, dicyclopentadiene type phenolic epoxy resin, naphthalene type epoxy resin, trifunctional type phenolic epoxy resin, and bisphenol A type phenolic epoxy resin. The modified epoxy resin is a silicone-modified epoxy resin and / or a silane-modified epoxy resin. The organosilicon resin is any one or more of methyl silicone resin, methyl phenyl silicone resin, and phenyl silicone resin; the curing agent is any one or more of 2-butylimidazole, 2-ethyl-4-methylimidazole, 2-ethylimidazole, 2-methylimidazole, 2-phenylimidazole, and 1-benzylimidazole.

5. The method for preparing the high-insulation, high-temperature moisture-sensitive granulated powder for inductors as described in claim 1, characterized in that, The solvent is one or more of ethanol, propanol, butanol, pentanol, acetone, butanone, pentanone, ethyl acetate, butyl acetate, ethylene glycol methyl ether, and dimethylformamide.

6. The method for preparing the high-insulation, high-temperature moisture-sensitive granulated powder for inductors as described in claim 1, characterized in that, The release agent is one or more of a metal stearate salt or a polyether compound.

7. A high-insulation, high-temperature, moisture-sensitive granulating powder for inductors, characterized in that, The granulated powder is prepared by the preparation method described in any one of claims 1-6.

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