Preparation process of high-voltage-withstanding integrally-formed inductor and integrally-formed inductor of high-voltage-withstanding integrally-formed inductor

Abstract

The invention relates to the field of production of electronic components, in particular to a preparation process of a high-voltage-resistance integrally-formed inductor and the integrally-formed inductor. The invention discloses a preparation process of a high-voltage-withstanding integrally-formed inductor. The preparation process comprises the following steps: preparing a voltage-withstanding sheet; filling the mixture into a T-Core mold cavity; continuously filling the magnetic powder, and carrying out preliminary pressing to form a T-Core composite structure; after the coil is sleeved, filling into a pressing mold for secondary pressing to finish integrated forming, so as to form an inductor semi-finished product; spraying an insulating protective layer on the surface, and metallizing the surface of the electrode area to obtain the high-voltage-resistance integrally-formed inductor. The invention aims to solve the problem of short circuit or high-frequency premature senility caused by the fact that a coil and magnetic powder are stressed and an insulating layer is insufficient in withstand voltage in an existing inductor preparation process. The high-voltage-withstanding integrally-formed inductor has the advantages that the product yield is improved under the condition that the high inductance value is kept, the breakdown voltage is high, the problem of stress of the coil and the magnetic powder is effectively solved, and the insulation and voltage-withstanding strength is high.

Description

Technical Field

[0001] The present application relates to the field of electronic component production, and specifically to a preparation process of a high-voltage withstand integrated inductor and the integrated inductor thereof. Background Art

[0002] As a key component in modern electronic products, the integrated inductor is widely used in fields such as power management and signal filtering. With the development trend of electronic devices towards miniaturization and high efficiency, the demand for integrated inductors is increasing day by day. Such inductors can not only effectively reduce electromagnetic interference, but also improve the overall performance and reliability of the circuit, which is of great significance for promoting the thin and light design of consumer electronic products.

[0003] Currently, during the pressing process of the integrated inductor, the voltage withstand of the insulating layer between the coil and the magnetic powder is insufficient and is easily damaged, resulting in short circuits or high-frequency premature aging. The short-circuit paths are mainly copper wire - powder - copper wire and copper wire - powder - electrode. Therefore, in order to address the problem of insufficient insulation voltage withstand, the industry usually adopts various means for improvement. On the one hand, by optimizing the assembly process between the coil and the magnetic core, such as adjusting the pressure parameters to avoid over-extrusion causing damage to the insulating layer; on the other hand, selecting higher-quality raw materials, such as enhanced magnetic powder or specially treated conductive wire materials, and introducing more precise electrode production to ensure good contact without damaging the internal structure. However, it is found in the actual application process that these traditional measures still have obvious limitations; because in order to protect the insulating coil from damage, it is necessary to avoid excessive forming pressure, thus restricting the pressing density of the product, affecting the inductor performance. When facing a high-voltage forming environment, the insulating coil will have the paint film damaged due to excessive pressure and short-circuit with each other, and the stress generated by the direct contact between the copper wire, powder, and electrode may lead to insulation failure, further causing problems such as short circuits or high-frequency characteristic decline. Summary of the Invention

[0004] Aiming at the problem in the existing inductor preparation process that due to the stress on the coil and the magnetic powder, the voltage withstand of the insulating layer is insufficient and short circuits or high-frequency premature aging occur after being damaged, the present application provides a preparation process of a high-voltage withstand integrated inductor and the integrated inductor thereof.

[0005] In the first aspect, the present application provides a preparation process of a high-voltage withstand integrated inductor, adopting the following technical solution: A preparation process of a high-voltage withstand integrated inductor includes the following steps: S1: Prepare a voltage withstand thin sheet: Take a voltage withstand material and press it into a thin sheet with a thickness of 0.005 - 0.5 mm. The voltage withstand material includes voltage withstand powder; the voltage withstand powder includes one or more of ceramic powder, stainless steel powder, and voltage withstand alloy powder; S2: Fill the pressed voltage withstand thin sheet into the cavity of the T-Core mold; S3: Continue to fill the T-Core mold cavity with magnetic powder and conduct preliminary pressing to form a T-Core composite structure; S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing to complete integrated molding, forming a semi-finished inductor; S5: Spray an insulating protective layer on the surface of the obtained integrated finished product, and conduct surface metallization treatment on the electrode area to obtain a high-voltage-resistant integrated molded inductor.

[0006] By adopting the above technical solutions, by introducing high-performance voltage-resistant powder, optimizing the magnetic powder structure, adopting an insulating layer design, and precise surface treatment processes, the insulation voltage-resistant performance of the inductor is significantly improved. Specifically, the combined structure of powder flakes and magnetic powder effectively isolates the direct contact between the copper wire, powder material, and electrode, avoids insulation failure caused by stress concentration, and can maintain stability in a high-voltage environment; the surface treatment process further enhances the reliability and consistency of the overall structure, improving the overall performance and service life of the inductor.

[0007] The voltage-resistant performance of the inductor can be effectively improved through the voltage-resistant flakes. Using ceramic powder, stainless steel powder, or voltage-resistant alloy powder as the voltage-resistant material can significantly improve the insulation performance and high-voltage resistance ability of the voltage-resistant flakes. The voltage-resistant material itself has excellent insulation characteristics and mechanical strength, and can effectively reduce the risk of insulation failure caused by pressure during the pressing process, thereby reducing the short-circuit probability and improving the overall reliability and high-frequency performance of the inductor. And voltage-resistant flakes within a certain thickness range can ensure good molding effects during the pressing process, and can also avoid a decrease in insulation performance caused by being too thick or insufficient mechanical strength caused by being too thin, improving the overall reliability and service life of the inductor.

[0008] In a specific feasible implementation, in the S5 step, the insulating protective layer includes one or both of an epoxy resin or a polyimide insulating protective layer.

[0009] The surface metallization treatment in the S5 step includes tin dipping and electroplating treatment.

[0010] By adopting the above technical solutions, since the insulating protective layer of the inductor semi-finished product is composed of epoxy resin or polyimide material, it has excellent heat resistance and electrical insulation performance, can effectively improve the overall voltage-resistant ability of the inductor, reduce the short-circuit risk, and at the same time improve the reliability and stability of the product. The insulating protective layer can protect the materials inside the inductor from oxidation and damage in a high-temperature environment, and at the same time provide good electrical insulation, improving the working stability of the inductor at high temperatures.

[0011] In a specific possible implementation scheme, the magnetic powder is a core-shell composite magnetic powder, and its preparation method includes taking sendust magnetic powder, depositing an Al2O3 layer by plasma chemical deposition, immersing the prepared Al2O3 coated magnetic powder in an ethanol solution containing tetraethyl orthosilicate, adding hydrochloric acid, ultrasonicating for 30 minutes, and then supercritically drying it at a temperature of 280-350°C and a pressure of 12-25MPa to form a SiO2 coating layer, adding the above SiO2 coating layer to a mixed solution of ZnO nanoparticles and polyvinyl pyrrolidone, and ultrasonicating for 15 minutes to obtain a core-shell composite magnetic powder.

[0012] The mass ratio of tetraethyl orthosilicate, ethanol and water is 1:(2-3):3.

[0013] The mass ratio of the ZnO nanoparticles to polyvinyl pyrrolidone is 1:(0.2-0.5).

[0014] By adopting the above technical solution, the core-shell composite structure formed by the unique preparation process significantly improves the overall pressure resistance of the magnetic powder. The multi-layer coating structure effectively disperses the external pressure and reduces the stress concentration point, making it difficult for the magnetic powder to be structurally damaged when subjected to high pressure, thereby ensuring the stability and reliability of the magnetic powder under high pressure environment, avoiding insufficient insulation and pressure resistance, and causing the copper wire-powder-copper wire short circuit phenomenon. The Al2O3 layer improves the initial insulation and mechanical strength of the magnetic powder, enhances the pressure resistance and insulation, and also lays the foundation for the formation of the subsequent coating layer. The SiO2 coating layer further enhances the insulation performance. Its network structure improves the stability of the overall structure, further improves the pressure resistance, and reduces the electromagnetic interference between the magnetic powders, stabilizing the inductance value; ZnO nanoparticles improve electrical properties, improve pressure resistance and inductance performance, and PVP ensures its uniform dispersion, thereby ensuring the insulation, mechanical properties and electrical properties work together to improve the pressure resistance, inductance value and insulation of the magnetic powder. Without the Al2O3 layer, the initial insulation performance of the magnetic powder will be greatly reduced, and it is easily affected by external electromagnetic interference, resulting in unstable inductance value. At the same time, the mechanical strength is reduced. Under the action of pressure, the inner core iron silicon aluminum magnetic powder is easily damaged, the overall pressure resistance performance deteriorates, and the formation of the subsequent coating layer will also be affected. The applicant found that when tetraethyl orthosilicate, ethanol and water are within a certain proportion range, a continuous and dense coating layer can be formed, thereby effectively improving the insulation performance and pressure resistance of the magnetic powder, and at the same time playing a positive role in stabilizing the inductance value. If the proportion of ethanol is too high, the reaction system will be diluted, resulting in a slower rate of hydrolysis and polymerization of tetraethyl orthosilicate, insufficient amount of SiO2 generated, and inability to form a complete and dense coating layer, thereby reducing the insulation and pressure resistance of the magnetic powder, and the inductance value will also be unstable due to poor electromagnetic shielding effect.

[0015] A certain proportion of ZnO nanoparticles and polyvinylpyrrolidone stabilize the inductance value and enhance the voltage withstand performance. PVP can effectively disperse ZnO nanoparticles and make them evenly distributed on the surface of magnetic powder. An appropriate amount of ZnO nanoparticles can give full play to their semiconductor and high dielectric constant characteristics, optimize the electrical properties of magnetic powder, and improve the voltage withstand and inductance performance. If the proportion of PVP is too low, ZnO nanoparticles are prone to agglomeration, resulting in local electric field concentration and reducing the voltage withstand performance.

[0016] In a specific feasible embodiment, the voltage withstand material further includes ethyl cellulose and terpineol.

[0017] The mass ratio of the voltage withstand powder, ethyl cellulose and terpineol is (5 - 7):(1 - 2):1.

[0018] By adopting the above technical solution, the voltage withstand powder can form a continuous and dense insulating structure under the bonding action of ethyl cellulose. Terpineol increases fluidity, promotes the uniform dispersion of the voltage withstand powder, fills the voids inside the inductor, reduces the electric field concentration phenomenon, and thus effectively improves the voltage withstand ability of the inductor. If the amount of ethyl cellulose is less, the bonding force is insufficient, and the voltage withstand powder is prone to agglomeration and separation, resulting in poor uniformity and consistency of the voltage withstand thin sheet and affecting the overall performance of the inductor. If there is too much ethyl cellulose, it will change the internal structure and spatial distribution of the inductor, have a certain impact on the magnetic circuit, and then lead to a decrease in the stability of the inductance value. Too much voltage withstand powder will increase the viscosity of the slurry and reduce its fluidity, resulting in difficulty in uniformly filling the die cavity during the pressing process, prone to voids and defects, affecting the quality and integrity of the voltage withstand thin sheet, and further reducing the voltage withstand performance of the inductor.

[0019] In the second aspect, an integrated inductor prepared by the preparation process of the high voltage withstand integrated inductor of the present application.

[0020] To sum up, the present application has the following beneficial effects: 1. By introducing high-performance voltage withstand powder, optimizing the magnetic powder structure, adopting an insulating layer design and a precise surface treatment process, the insulation voltage withstand performance of the inductor is significantly improved. Specifically, the combined structure of the powder thin sheet and the magnetic powder effectively isolates the direct contact between the copper wire and the powder material, avoids insulation failure caused by stress concentration and can remain stable in a high-voltage environment; the surface treatment process further enhances the reliability and consistency of the overall structure. The overall performance and service life of the inductor are improved. The voltage withstand thin sheet can effectively improve the voltage withstand performance of the inductor. Using ceramic powder, stainless steel powder or voltage withstand alloy powder as the voltage withstand material can significantly improve the insulation performance and high-voltage resistance ability of the voltage withstand thin sheet. The voltage withstand material itself has excellent insulation characteristics and mechanical strength, and can effectively reduce the risk of insulation failure caused by pressure during the pressing process, thereby reducing the short-circuit probability and improving the overall reliability and high-frequency performance of the inductor.

[0021] 2. The insulating protective layer of the semi-finished inductor is made of epoxy resin or polyimide material. These two materials have excellent heat resistance and electrical insulation properties, which can effectively improve the overall voltage resistance of the inductor, reduce the risk of short circuit, and improve the reliability and stability of the product. Among them, polyimide has high molecular chain rigidity and aromatic structure, and the insulating protective layer formed has excellent high temperature resistance and insulation performance. The insulating protective layer can protect the materials inside the inductor from oxidation and damage in a high temperature environment, while providing good electrical insulation and improving the working stability of the inductor at high temperatures.

[0022] 3. The core-shell composite structure formed by a unique preparation process significantly improves the overall pressure resistance of the magnetic powder. The multi-layer coating structure effectively disperses the external pressure and reduces the stress concentration points, making it difficult for the magnetic powder to be structurally damaged when subjected to high pressure, thereby ensuring the stability and reliability of the magnetic powder under high pressure. The Al2O3 layer improves the initial insulation and mechanical strength of the magnetic powder, enhances the pressure resistance and insulation, and also lays the foundation for the formation of the subsequent coating layer. The SiO2 coating layer further enhances the insulation performance. Its network structure improves the stability of the overall structure and further improves the pressure resistance. At the same time, it reduces the electromagnetic interference between the magnetic powders and stabilizes the inductance value. ZnO nanoparticles improve electrical properties, improve pressure resistance and inductance performance, and PVP ensures its uniform dispersion, thereby ensuring the insulation, mechanical properties and electrical properties work together to improve the pressure resistance, inductance value and insulation of the magnetic powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a cross-sectional view of the one-piece molded inductor provided in Example 1 of the present application.

[0024] Explanation of the reference numerals: 1. magnetic powder; 2. coil; 3. electrode; 4. pressure-resistant sheet; 5. electrode area coating. DETAILED DESCRIPTION

[0025] The present application is further described in detail below with reference to the embodiments.

[0026] Some raw materials used in the preparation examples and embodiments: Fe-Si-Al powder has a particle size of D50=5 μm; related raw materials used in the embodiments and comparative examples that are not specified are all conventional products that can be purchased on the market.

[0027] Preparation Example 1 Preparation of core-shell composite magnetic powder: Take Fe-Si-Al magnetic powder, clean it with ethanol, and then dry it in vacuum at 60 °C for 2 h. Load it into the deposition chamber. For alumina ceramic powder, use N2 as the powder feeding gas, with a spraying distance of 80 mm, a powder feeding rate of 4 g / s, and a particle velocity of 25 m / s. After a deposition time of 4 min, Al2O3-coated magnetic powder is obtained; Immerse the above-obtained Al2O3-coated magnetic powder into a solution containing tetraethyl orthosilicate, ethanol, and water with a mass ratio of 1:2:3, and then add 0.5 g of hydrochloric acid with a mass fraction of 5%. Ultrasonic for 30 min, and tetraethyl orthosilicate undergoes hydrolysis and polycondensation to form a precursor of SiO2 coating layer on the surface of Al2O3-coated magnetic powder. Then, perform supercritical drying at a temperature of 280 °C and a pressure of 12 MPa to form a SiO2 coating layer. Add the above SiO2 coating layer to a mixed solution with a mass ratio of ZnO nanoparticles to polyvinylpyrrolidone of 1:0.3, and ultrasonic for 15 min to make ZnO nanoparticles and polyvinylpyrrolidone uniformly adhere to the surface of the magnetic powder, which is the core-shell composite magnetic powder.

[0028] Preparation Example 2 Preparation of core-shell composite magnetic powder: Take Fe-Si-Al magnetic powder, clean it with ethanol, and then dry it in vacuum at 60 °C for 2 h. Load it into the deposition chamber. For alumina ceramic powder, use N2 as the powder feeding gas, with a spraying distance of 80 mm, a powder feeding rate of 4 g / s, and a particle velocity of 25 m / s. After a deposition time of 4 min, Al2O3-coated magnetic powder is obtained; Immerse the above-obtained Al2O3-coated magnetic powder into a solution containing tetraethyl orthosilicate, ethanol, and water with a mass ratio of 1:5:3, and then add 0.5 g of hydrochloric acid with a mass fraction of 5%. Ultrasonic for 30 min, and tetraethyl orthosilicate undergoes hydrolysis and polycondensation to form a precursor of SiO2 coating layer on the surface of Al2O3-coated magnetic powder. Then, perform supercritical drying at a temperature of 280 °C and a pressure of 12 MPa to form a SiO2 coating layer. Add the above SiO2 coating layer to a mixed solution with a mass ratio of ZnO nanoparticles to polyvinylpyrrolidone of 1:0.3, and ultrasonic for 15 min to make ZnO nanoparticles and polyvinylpyrrolidone uniformly adhere to the surface of the magnetic powder, which is the core-shell composite magnetic powder.

[0029] Preparation Example 3 Preparation of core-shell composite magnetic powder: Take Fe-Si-Al magnetic powder, clean it with ethanol, and then dry it in vacuum at 60 °C for 2 h. Load it into the deposition chamber. For alumina ceramic powder, use N2 as the powder feeding gas, with a spraying distance of 80 mm, a powder feeding rate of 4 g / s, and a particle velocity of 25 m / s. After a deposition time of 4 min, Al2O3-coated magnetic powder is obtained; Add the above Al2O3-coated magnetic powder to a mixed solution with a mass ratio of ZnO nanoparticles to polyvinylpyrrolidone of 1:0.3, and ultrasonic for 15 min to make ZnO nanoparticles and polyvinylpyrrolidone uniformly adhere to the surface of the magnetic powder, which is the core-shell composite magnetic powder.

[0030] Preparation Example 4 Preparation of core-shell composite magnetic powder: Take iron-silicon-aluminum magnetic powder, clean it with ethanol, and then dry it in vacuum at 60 °C for 2 h. Load it into the deposition chamber. For aluminum oxide ceramic powder, use N2 as the powder feeding gas, with a spraying distance of 80 mm, a powder feeding rate of 4 g / s, and a particle velocity of 25 m / s. After a deposition time of 4 min, Al2O3-coated magnetic powder is obtained. Immerse the obtained Al2O3-coated magnetic powder into a solution containing tetraethyl orthosilicate, ethanol, and water with a mass ratio of 1:2:3, and then add 0.5 g of hydrochloric acid with a mass fraction of 5%. Ultrasonic for 30 min, and tetraethyl orthosilicate undergoes hydrolysis and polycondensation to form a precursor of the SiO2 coating layer on the surface of the Al2O3-coated magnetic powder. Then, perform supercritical drying on it at a temperature of 280 °C and a pressure of 12 MPa to form the SiO2 coating layer. Add the above SiO2 coating layer to a mixed solution of ZnO nanoparticles and polyvinylpyrrolidone with a mass ratio of 1.2:0.1, and ultrasonic for 15 min to make the ZnO nanoparticles and polyvinylpyrrolidone uniformly adhere to the surface of the magnetic powder, which is the core-shell composite magnetic powder.

[0031] Preparation Example 5 Preparation of core-shell composite magnetic powder: Take iron-silicon-aluminum magnetic powder, clean it with ethanol, and then dry it in vacuum at 60 °C for 2 h. Load it into the deposition chamber. For aluminum oxide ceramic powder, use N2 as the powder feeding gas, with a spraying distance of 80 mm, a powder feeding rate of 4 g / s, and a particle velocity of 25 m / s. After a deposition time of 4 min, Al2O3-coated magnetic powder is obtained. Immerse the obtained Al2O3-coated magnetic powder into a solution containing tetraethyl orthosilicate, ethanol, and water with a mass ratio of 1:2:3, and then add 0.5 g of hydrochloric acid with a mass fraction of 5%. Ultrasonic for 30 min, and tetraethyl orthosilicate undergoes hydrolysis and polycondensation to form a precursor of the SiO2 coating layer on the surface of the Al2O3-coated magnetic powder. Then, perform supercritical drying on it at a temperature of 280 °C and a pressure of 12 MPa to form the SiO2 coating layer, which is the core-shell composite magnetic powder.

[0032] Preparation Example 6 Preparation of core-shell composite magnetic powder: Take iron-silicon-aluminum magnetic powder, clean it with ethanol, and then dry it in vacuum at 60 °C for 2 h. Immerse it into a solution containing tetraethyl orthosilicate, ethanol, and water with a mass ratio of 1:2:3, and then add 0.5 g of hydrochloric acid with a mass fraction of 5%. Ultrasonic for 30 min, and tetraethyl orthosilicate undergoes hydrolysis and polycondensation to form a precursor of the SiO2 coating layer on the surface of the Al2O3-coated magnetic powder. Then, perform supercritical drying on it at a temperature of 280 °C and a pressure of 12 MPa to form the SiO2 coating layer. Add the above SiO2 coating layer to a mixed solution of ZnO nanoparticles and polyvinylpyrrolidone with a mass ratio of 1:0.4, and ultrasonic for 15 min to make the ZnO nanoparticles and polyvinylpyrrolidone uniformly adhere to the surface of the magnetic powder, which is the core-shell composite magnetic powder.

[0033] Preparation Example 7 Add ethyl cellulose to terpineol and stir for 10 min. Add stainless steel powder and continue stirring for 20 min. The mass ratio of the pressure-resistant powder, ethyl cellulose, and terpineol is 7:2:1. Transfer the mixed material to a ball mill and ball mill for 2 h to obtain the pressure-resistant material.

[0034] Preparation Example 8 Add ethyl cellulose to terpineol and stir for 10 min. Add stainless steel powder and continue stirring for 20 min. The mass ratio of the pressure-resistant powder, ethyl cellulose, and terpineol is 5:4:1. Transfer the mixed material to a ball mill and ball mill for 2 h to obtain the pressure-resistant material.

[0035] Example 1 As Figure 1 shown, a one-piece molded inductor includes a pressure-resistant thin sheet, magnetic powder on the pressure-resistant thin sheet, a coil is arranged between the magnetic powder and the pressure-resistant thin sheet, pins are arranged at both ends of the coil, the pins are all located on the pressure-resistant thin sheet to form electrodes, and an electrode region coating is arranged on the part of the electrode protruding from the pressure-resistant thin sheet.

[0036] A preparation process of a high-pressure-resistant one-piece molded inductor. S1: Prepare the pressure-resistant thin sheet: Take the pressure-resistant material and press it into a thin sheet with a thickness of 0.5 mm. The pressure-resistant material is stainless steel powder. S2: Fill the pressed pressure-resistant thin sheet into the cavity of the T-Core mold. S3: Continue to fill the cavity of the T-Core mold with iron-silicon-aluminum magnetic powder and perform preliminary pressing. The cold pressing pressure is 6 t / cm 2 , after the holding pressure time is 3 s, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving the coil on the formed T-Core composite structure, fill it into the pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the holding pressure time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the one-piece molding to form an inductor semi-finished product. S5: Use a constant-temperature heating spraying device to coat a layer of epoxy resin protective material on the surface of the inductor semi-finished product prepared in step S4, and bake at 170 °C for 1 h to cure; Use a laser paint stripping device to strip the insulating protective material and copper wire paint skin at the electrode to expose the bottom electrode region, and then by dipping tin on the surface of the electrode region, at 300 °C, uniformly attach the tin-copper alloy to the electrode surface to form an electrode region coating to obtain a high-pressure-resistant one-piece molded inductor.

[0037] Example 2 Preparation process of a high-voltage withstand integrated inductor. S1: Prepare a voltage withstand thin sheet: Take a voltage withstand material and press it into a thin sheet with a thickness of 0.005 mm. The voltage withstand material is ceramic powder. S2: Fill the pressed voltage withstand thin sheet into the cavity of the T-Core mold. S3: Continue to fill the cavity of the T-Core mold with iron-silicon-aluminum magnetic powder and conduct preliminary pressing. The cold pressing pressure is 6 t / cm2, and after the holding pressure time of 3 s, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the holding pressure time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integrated molding to form an inductor semi-finished product. S5: Use a constant-temperature heating spraying device to coat a layer of epoxy resin protective material on the surface of the inductor semi-finished product obtained in step S4, and bake at 170 °C for 1 h for curing; Use a laser paint stripping device to strip the insulating protective material and copper wire paint skin at the electrode to expose the bottom electrode area, and then by means of tin dipping on the surface of the electrode area, at 300 °C, evenly attach the tin-copper alloy on the electrode surface to form an electrode area coating, and obtain a high-voltage withstand integrated inductor.

[0038] Example 3 Preparation process of a high-voltage withstand integrated inductor. S1: Prepare a voltage withstand thin sheet: Take a voltage withstand material and press it into a thin sheet with a thickness of 0.5 mm. The voltage withstand material is stainless steel powder. S2: Fill the pressed voltage withstand thin sheet into the cavity of the T-Core mold. S3: Continue to fill the cavity of the T-Core mold with the magnetic powder prepared in Preparation Example 1 and conduct preliminary pressing. The cold pressing pressure is 6 t / cm2, and after the holding pressure time of 3 s, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the holding pressure time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integrated molding to form an inductor semi-finished product. S5: Use a constant-temperature heating spraying device to coat a layer of epoxy resin protective material on the surface of the inductor semi-finished product obtained in step S4, and bake at 170 °C for 1 h for curing; Use a laser paint stripping device to strip the insulating protective material and copper wire paint skin at the electrode to expose the bottom electrode area, and then by means of tin dipping on the surface of the electrode area, at 300 °C, evenly attach the tin-copper alloy on the electrode surface to form an electrode area coating, and obtain a high-voltage withstand integrated inductor.

[0039] Example 4 Preparation process of a high-voltage-resistant integrally formed inductor. S1: Prepare a high-voltage-resistant thin sheet: Take a high-voltage-resistant material and press it into a thin sheet with a thickness of 0.5 mm. The high-voltage-resistant material is stainless steel powder. S2: Fill the pressed high-voltage-resistant thin sheet into the cavity of the T-Core mold. S3: Continuously fill the magnetic powder obtained in Preparation Example 2 into the cavity of the T-Core mold, and perform preliminary pressing. The cold pressing pressure is 6 t / cm2, and after the holding pressure time of 3 s, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the holding pressure time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integral forming to form an inductor semi-finished product. S5: Use a constant-temperature heating spraying device to coat a layer of epoxy resin protection material on the surface of the inductor semi-finished product obtained in Step S4, and bake at 170 °C for 1 h for curing; Use a laser paint stripping device to strip the insulating protection material and copper wire paint skin at the electrode to expose the bottom electrode area. Subsequently, by means of tin dipping on the surface of the electrode area, at 300 °C, uniformly attach the tin-copper alloy to the electrode surface to form an electrode area coating, and obtain a high-voltage-resistant integrally formed inductor.

[0040] Example 5 Preparation process of a high-voltage-resistant integrally formed inductor. S1: Prepare a high-voltage-resistant thin sheet: Take a high-voltage-resistant material and press it into a thin sheet with a thickness of 0.5 mm. The high-voltage-resistant material is stainless steel powder. S2: Fill the pressed high-voltage-resistant thin sheet into the cavity of the T-Core mold. S3: Continuously fill the magnetic powder obtained in Preparation Example 3 into the cavity of the T-Core mold, and perform preliminary pressing. The cold pressing pressure is 6 t / cm2, and after the holding pressure time of 3 s, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the holding pressure time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integral forming to form an inductor semi-finished product. S5: Use a constant-temperature heating spraying device to coat a layer of epoxy resin protection material on the surface of the inductor semi-finished product obtained in Step S4, and bake at 170 °C for 1 h for curing; Use a laser paint stripping device to strip the insulating protection material and copper wire paint skin at the electrode to expose the bottom electrode area. Subsequently, by means of tin dipping on the surface of the electrode area, at 300 °C, uniformly attach the tin-copper alloy to the electrode surface to form an electrode area coating, and obtain a high-voltage-resistant integrally formed inductor.

[0041] Example 6 Preparation process of a high-voltage withstand integrated inductor. S1: Prepare a voltage withstand thin sheet: Take a voltage withstand material and press it into a thin sheet with a thickness of 0.5 mm. The voltage withstand material is stainless steel powder. S2: Fill the pressed voltage withstand thin sheet into the cavity of the T-Core mold. S3: Continuously fill the magnetic powder obtained in Preparation Example 4 into the cavity of the T-Core mold, and conduct preliminary pressing. The cold pressing pressure is 6 t / cm2, and after the holding pressure time of 3 s, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the holding pressure time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integrated molding to form an inductor semi-finished product. S5: Use a constant temperature heating spraying device to coat a layer of epoxy resin protective material on the surface of the inductor semi-finished product obtained in step S4, and bake at 170 °C for 1 h for curing; Use a laser paint stripping device to strip the insulating protective material and copper wire paint skin at the electrode to expose the bottom electrode area. Subsequently, by means of tin dipping on the surface of the electrode area, at 300 °C, uniformly attach the tin-copper alloy to the electrode surface to form an electrode area coating, and obtain a high-voltage withstand integrated inductor.

[0042] Example 7 Preparation process of a high-voltage withstand integrated inductor. S1: Prepare a voltage withstand thin sheet: Take a voltage withstand material and press it into a thin sheet with a thickness of 0.5 mm. The voltage withstand material is stainless steel powder. S2: Fill the pressed voltage withstand thin sheet into the cavity of the T-Core mold. S3: Continuously fill the magnetic powder obtained in Preparation Example 5 into the cavity of the T-Core mold, and conduct preliminary pressing. The cold pressing pressure is 6 t / cm2, and after the holding pressure time of 3 s, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the holding pressure time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integrated molding to form an inductor semi-finished product. S5: Use a constant temperature heating spraying device to coat a layer of epoxy resin protective material on the surface of the inductor semi-finished product obtained in step S4, and bake at 170 °C for 1 h for curing; Use a laser paint stripping device to strip the insulating protective material and copper wire paint skin at the electrode to expose the bottom electrode area. Subsequently, by means of tin dipping on the surface of the electrode area, at 300 °C, uniformly attach the tin-copper alloy to the electrode surface to form an electrode area coating, and obtain a high-voltage withstand integrated inductor.

[0043] Example 8 Preparation process of a high-voltage-resistant integrally formed inductor. S1: Prepare a voltage-resistant thin sheet: Take a voltage-resistant material and press it into a thin sheet with a thickness of 0.5 mm. The voltage-resistant material is stainless steel powder. S2: Fill the pressed voltage-resistant thin sheet into the cavity of the T-Core mold. S3: Continuously fill the magnetic powder prepared in Preparation Example 6 into the cavity of the T-Core mold, and perform preliminary pressing. The cold pressing pressure is 6 t / cm2, and the pressure holding time is 3 s. After that, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the pressure holding time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integral molding to form an inductor semi-finished product. S5: Use a constant-temperature heating spraying device to coat a layer of epoxy resin protective material on the surface of the inductor semi-finished product obtained in Step S4, and bake at 170 °C for 1 h for curing; Use a laser paint stripping device to strip off the insulating protective material and copper wire paint skin at the electrode to expose the bottom electrode area. Subsequently, by means of tin dipping on the surface of the electrode area, at 300 °C, evenly attach the tin-copper alloy to the electrode surface to form an electrode area coating, and obtain a high-voltage-resistant integrally formed inductor.

[0044] Example 9 Preparation process of a high-voltage-resistant integrally formed inductor. S1: Prepare a voltage-resistant thin sheet: Take a voltage-resistant material and press it into a thin sheet with a thickness of 0.5 mm. The voltage-resistant material is the voltage-resistant material prepared in Preparation Example 7. S2: Fill the pressed voltage-resistant thin sheet into the cavity of the T-Core mold. S3: Continuously fill the magnetic powder prepared in Preparation Example 1 into the cavity of the T-Core mold, and perform preliminary pressing. The cold pressing pressure is 6 t / cm2, and the pressure holding time is 3 s. After that, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the pressure holding time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integral molding to form an inductor semi-finished product. S5: Use a constant-temperature heating spraying device to coat a layer of epoxy resin protective material on the surface of the inductor semi-finished product obtained in Step S4, and bake at 170 °C for 1 h for curing; Use a laser paint stripping device to strip off the insulating protective material and copper wire paint skin at the electrode to expose the bottom electrode area. Subsequently, by means of tin dipping on the surface of the electrode area, at 300 °C, evenly attach the tin-copper alloy to the electrode surface to form an electrode area coating, and obtain a high-voltage-resistant integrally formed inductor.

[0045] Example 10 Preparation process of a high-voltage withstand integrated inductor. S1: Prepare the high-voltage withstand thin sheet: Take the high-voltage withstand material and press it into a thin sheet with a thickness of 0.5 mm. The high-voltage withstand material is the high-voltage withstand material obtained in Preparation Example 8. S2: Fill the pressed high-voltage withstand thin sheet into the cavity of the T-Core mold. S3: Continue to fill the magnetic powder obtained in Preparation Example 1 into the cavity of the T-Core mold and conduct preliminary pressing. The cold pressing pressure is 6 t / cm2, and the pressure holding time is 3 s. After that, bake at 160 °C for 25 min to form a T-Core composite structure. S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the pressure holding time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integrated molding to form an inductor semi-finished product. S5: Use a constant-temperature heating spraying device to coat a layer of epoxy resin protective material on the surface of the inductor semi-finished product obtained in Step S4, and bake at 170 °C for 1 h to cure. Use a laser paint stripping device to strip the insulating protective material and copper wire paint skin at the electrode to expose the bottom electrode area. Subsequently, by means of tin dipping on the surface of the electrode area, at 300 °C, uniformly attach the tin-copper alloy to the electrode surface to form an electrode area coating, and obtain a high-voltage withstand integrated inductor.

[0046] Comparative Example 1 Preparation process of a high-voltage withstand integrated inductor. Fill the iron-silicon-aluminum magnetic powder into the cavity of the T-Core mold and conduct preliminary pressing. The cold pressing pressure is 6 t / cm2, and the pressure holding time is 3 s. After that, bake at 160 °C for 25 min to form a T-Core composite structure. After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing. The hot pressing pressure is 6 t / cm2, the pressure holding time is 180 s, the baking temperature is 170 °C, and bake for 2 h to complete the integrated molding to form an inductor semi-finished product. Use a constant-temperature heating spraying device to coat a layer of epoxy resin protective material on the surface of the inductor semi-finished product obtained in Step S4, and bake at 170 °C for 1 h to cure. Use a laser paint stripping device to strip the insulating protective material and copper wire paint skin at the electrode to expose the bottom electrode area. Subsequently, by means of tin dipping on the surface of the electrode area, at 300 °C, uniformly attach the tin-copper alloy to the electrode surface to form an electrode area coating, and obtain a high-voltage withstand integrated inductor.

[0047] Performance testing For the integrated inductors obtained in the examples and comparative examples, 200 pieces are produced respectively. The finished product is an inductor with a size of 1.5 mm * 1.8 mm * 0.85 mm. The performance test is carried out by the following method: Inductor performance test: Use a 3260B type LCR tester to test the inductance value of the initial magnetic permeability μi (1 V / 1 MHz) of the magnetic ring sample.

[0048] Inductor withstand voltage performance: Use DSM-8104 withstand voltage tester to test the breakdown voltage between the product coil and the magnet (leakage current 1mA); each sample of the above test is tested three times, and the average value is taken. The comparison results are shown in Table 1 below: Table 1 Performance test results Inductance value L / μH Yield rate (%) Breakdown voltage / V Example 1 0.42 91 138 Example 2 0.41 90 137 Example 3 0.49 97 154 Example 4 0.48 95 152 Example 5 0.48 94 150 Example 6 0.47 96 151 Example 7 0.44 93 148 Example 8 0.45 92 145 Example 9 0.49 99 156 Example 10 0.52 98 155 Comparative Example 1 0.34 71 102 It can be seen from Table 1 that the preparation process of the high-voltage-withstand one-piece molded inductor obtained in the above embodiment has the advantages of maintaining a high inductance value, improving product yield, mechanical voltage resistance and crushing strength, and having a high breakdown voltage, and effectively solving the problems of short circuit or high-frequency premature aging caused by stress on the coil and magnetic powder and insufficient insulation voltage resistance.

[0049] Compared with Comparative Example 1 and Example 1, it can be seen that the insulation and voltage resistance performance of the inductor are significantly improved by introducing high-performance voltage-resistant powder, optimizing the magnetic powder structure, adopting an insulating layer design and a precise surface treatment process. The combined structure of powder flakes and magnetic powder effectively isolates the direct contact between the copper wire, powder material and electrode, avoids insulation failure caused by stress concentration and can remain stable under high-voltage environment; the voltage-resistant performance of the inductor can be effectively improved by the voltage-resistant flakes, and the use of ceramic powder, stainless steel powder or voltage-resistant alloy powder as voltage-resistant materials can significantly improve the insulation performance and high-voltage resistance of the voltage-resistant flakes. The voltage-resistant material itself has excellent insulation properties and mechanical strength, which can effectively reduce the risk of insulation failure caused by pressure during the pressing process, thereby reducing the probability of short circuits and improving the overall reliability and high-frequency performance of the inductor.

[0050] Comparing Example 1 and Example 3-8, it can be seen that by forming a core-shell composite structure, the overall withstand voltage performance of the magnetic powder is significantly improved. The multilayer coating structure effectively disperses the external pressure, reduces the stress concentration point, and makes the magnetic powder less prone to structural damage when subjected to higher pressure, thereby ensuring the stability and reliability of the magnetic powder under high pressure, avoiding insufficient insulation withstand voltage, and causing the copper wire-powder-copper wire short circuit phenomenon. In the absence of an Al2O3 layer, the initial insulation performance of the magnetic powder will be greatly reduced, and it is susceptible to external electromagnetic interference, resulting in unstable inductance. At the same time, the mechanical strength is reduced, and under pressure, the inner core iron silicon aluminum magnetic powder is susceptible to damage, and the overall withstand voltage performance deteriorates, which reduces the product yield, and the insulation and withstand voltage performance and inductance value are all affected. It can be seen from Example 3 and Example 6 that a certain proportion of ZnO nanoparticles and polyvinyl pyrrolidone stabilize the inductance value and enhance the withstand voltage performance, and PVP can effectively disperse the ZnO nanoparticles so that they are evenly distributed on the surface of the magnetic powder. The right amount of ZnO nanoparticles can give full play to their semiconductor and high dielectric constant properties, optimize the electrical properties of magnetic powder, and improve the withstand voltage and inductance performance. If the PVP ratio is too low, the ZnO nanoparticles are prone to agglomeration, resulting in local electric field concentration and reducing the withstand voltage performance.

[0051] Comparing Comparative Example 3 with Examples 9-10, it can be seen that a certain proportion of voltage-resistant powder, ethyl cellulose, and terpineol can increase the pressing density, thereby improving the inductance performance and having stronger voltage resistance; the voltage-resistant powder can form a continuous and dense insulating structure under the bonding action of ethyl cellulose, and terpineol increases fluidity, promotes the uniform dispersion of the voltage-resistant powder, fills the voids inside the inductor, and reduces the electric field concentration phenomenon, thereby effectively improving the voltage resistance of the inductor. When the amount of ethyl cellulose is small, the bonding force is insufficient, and the voltage-resistant powder is prone to agglomeration and separation, resulting in poor uniformity and consistency of the voltage-resistant thin sheet and affecting the overall performance of the inductor.

[0052] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A preparation process for a high-voltage withstand integrated inductor, characterized in that: It includes the following steps: S1: Prepare a pressure-resistant thin sheet: Take a pressure-resistant material and press it into a thin sheet with a thickness of 0.005 - 0.5 mm. The pressure-resistant material includes pressure-resistant powder; the pressure-resistant powder includes one or more of ceramic powder, stainless steel powder, and pressure-resistant alloy powder; S2: Fill the pressed pressure-resistant thin sheet into the cavity of the T-Core mold; S3: Continuously fill magnetic powder into the cavity of the T-Core mold and perform preliminary pressing to form a T-Core composite structure; S4: After sleeving a coil on the formed T-Core composite structure, fill it into a pressing mold for secondary pressing to complete integrated molding and form an inductance semi-finished product; S5: Spray an insulating protective layer on the surface of the obtained integrated finished product, and perform surface metallization treatment on the electrode area to obtain a high-voltage-resistant integrated molded inductor.

2. The preparation process of the high-voltage withstand integrated inductor according to claim 1, wherein: In the S5 step, the insulating protective layer includes one or both of an epoxy resin or a polyimide insulating protective layer.

3. The preparation process of the high-voltage withstand integrated inductor according to claim 1, wherein: In the S5 step, the surface metallization treatment includes tin dipping and electroplating treatment.

4. The preparation process of the high-voltage withstand integrated inductor according to claim 1, characterized in that: The magnetic powder is a core-shell composite magnetic powder, and its preparation method includes taking an iron-silicon-aluminum magnetic powder, depositing an Al2O3 layer by plasma chemical deposition, immersing the prepared Al2O3-coated magnetic powder in an ethanol solution containing tetraethyl orthosilicate, adding hydrochloric acid, ultrasonicating for 30 min, and then performing supercritical drying on it at a temperature of 280 - 350 °C and a pressure of 12 - 25 MPa to form a SiO2 coating layer. Add the above SiO2 coating layer to a mixed solution of ZnO nanoparticles and polyvinylpyrrolidone, and ultrasonicate for 15 min to obtain the core-shell composite magnetic powder.

5. The preparation process of the high-voltage integrated inductor according to claim 4, characterized in that: The mass ratio of tetraethyl orthosilicate, ethanol, and water is 1:(2 - 3):

3.

6. The preparation process of the high-voltage withstand integrated inductor according to claim 4, characterized in that: The mass ratio of ZnO nanoparticles and polyvinylpyrrolidone is 1:(0.2 - 0.5).

7. The preparation process of the high-voltage withstand integrated inductor according to claim 1, wherein: The pressure-resistant material further includes ethyl cellulose and terpineol.

8. The preparation process of the high-voltage withstand integrated inductor according to claim 7, characterized in that: The mass ratio of the pressure-resistant powder, ethyl cellulose, and terpineol is (5 - 7):(1 - 2):

1.

9. An inductor prepared by using the preparation process of the high-voltage-resistant integrated molded inductor according to any one of claims 1 - 8.

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