Double-layer in-situ deposition amorphous powder material capable of improving anti-falling performance of inductor and preparation method of double-layer in-situ deposition amorphous powder material

Abstract

The invention belongs to the technical field of electronic component materials, and particularly discloses a double-layer in-situ deposition amorphous powder material capable of improving the anti-falling performance of an inductor and a preparation method of the double-layer in-situ deposition amorphous powder material. The method comprises the following steps: carrying out surface pretreatment on amorphous powder to clean and activate; then the corrosion inhibitor is loaded in pores of the powder material through vacuum impregnation; and finally, a tough organic-polymer composite coating layer is deposited on the surface of the powder material through in-situ polymerization reaction. By constructing a double-layer structure in which the internal corrosion inhibitor storage layer and the external tough polymer coating layer are combined, the mechanical strength of the amorphous powder and the anti-falling performance of the inductance element are remarkably improved, the coating layer of the powder is good in integrity in compression molding and subsequent processing, the powder is not prone to being damaged, and the anti-falling performance of the inductance element is improved. The structural integrity and the electromagnetic performance stability of the magnetic core are effectively maintained, and the magnetic core is suitable for high-performance inductance elements with strict requirements for falling reliability and environmental adaptability.

Description

Technical Field

[0001] This invention relates to the field of amorphous powder preparation technology, specifically to a double-layer in-situ deposited amorphous powder that can improve the drop resistance of inductors and its preparation method. Background Technology

[0002] Amorphous alloy powders, due to their excellent soft magnetic properties such as high permeability, low coercivity, and low high-frequency loss, have become the core magnetic core material for magnetic components such as high-frequency inductors and electronic transformers. With increasingly stringent reliability requirements for electronic equipment in fields such as new energy vehicles, high-speed communications, and aerospace, inductor components not only need to operate stably in complex electromagnetic environments but also must withstand continuous mechanical vibration, instantaneous impacts, and variable climatic conditions. This poses unprecedented challenges to the mechanical strength, structural integrity, and long-term environmental adaptability of amorphous magnetic cores.

[0003] However, existing amorphous powder materials have significant shortcomings in impact resistance and mechanical properties when used to prepare high-reliability inductor cores, mainly due to the following three interrelated fundamental problems: 1. Risk of stress concentration and crack initiation due to intrinsic structural defects. Amorphous powder materials are prone to introducing micron- or even submicron-scale internal pores and surface defects during the preparation process. These defects become significant stress concentration points when the powder material is pressed and subjected to impact loads, which can easily induce the nucleation and propagation of microcracks, leading to brittle fracture or structural disintegration of the magnetic core.

[0004] 2. Environmental corrosion and performance degradation caused by high surface chemical activity. The atomic arrangement on the surface of amorphous structures is disordered over a long range, resulting in high chemical activity. In harsh environments such as humidity and salt spray, oxidation or electrochemical corrosion can easily occur. Corrosion products not only destroy the integrity of the powder surface and weaken its mechanical properties, but also introduce non-magnetic impurities, leading to a decrease in the magnetic permeability of the magnetic core, an increase in losses, and irreversible degradation of electromagnetic performance.

[0005] 3. Weak interparticle bonding restricts overall structural strength. In traditional powder metallurgy processes, amorphous powder particles mainly rely on physical interlocking and the bonding effect of a small amount of organic binder, resulting in limited bonding strength. Under frequent vibration or mechanical impact, relative slippage or even detachment can easily occur between particles, leading to a loose core structure, uneven density, and severely impairing its mechanical load-bearing capacity and the consistency of its magnetic properties.

[0006] To address these issues, the industry typically employs surface modification methods for amorphous powders. For example, insulating layers are constructed on the powder surface using electroless plating, sol-gel methods, or physical vapor deposition. However, these traditional methods often have significant limitations: single inorganic coatings are brittle and prone to cracking under pressure or impact loads; while simple organic polymer coatings suffer from weak adhesion to the powder, poor heat resistance, and an inability to effectively fill internal pore defects. Existing technologies struggle to achieve synergistic improvements in powder porosity optimization, interfacial bonding enhancement, and environmental corrosion protection, resulting in modified amorphous powders often facing a trade-off between these aspects, failing to fully meet the stringent comprehensive performance requirements of high-end inductor components.

[0007] Therefore, it is necessary to develop a powder modification technology for inductors with high drop resistance, which can achieve synergistic control of the surface and pores of amorphous powder without significantly sacrificing magnetic properties and processability, and provide an effective crack passivation and energy dissipation mechanism under impact load, thereby significantly improving the drop resistance reliability of integral molded inductors. Summary of the Invention

[0008] The purpose of this invention is to provide a double-layer in-situ deposited amorphous powder material and its preparation method that can improve the drop resistance of inductors, with the aim of obtaining a high-strength, impact-resistant amorphous powder material.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for preparing a double-layer in-situ deposited amorphous powder material that can improve the drop resistance of inductors includes the following steps: (1) Surface pretreatment: The amorphous powder is cleaned and acid-etched to activate it, and then neutralized, washed, dehydrated and dried to obtain pretreated amorphous powder; (2) Corrosion inhibitor loading: The pretreated amorphous powder is immersed in an organic corrosion inhibitor solution and treated under vacuum or inert atmosphere to load the organic corrosion inhibitor onto the surface and pores of the powder. After post-treatment, the amorphous powder loaded with organic corrosion inhibitor is obtained. (3) In-situ polymerization coating: The amorphous powder loaded with organic corrosion inhibitor is dispersed in an alkaline buffer solution, and catechol compounds and amine compounds are added to carry out an in-situ polymerization reaction to form a composite polymer coating layer on the surface of the powder. The double-layer in-situ deposited amorphous powder is then obtained after post-treatment.

[0010] Further, in step (1), the acid etching activation treatment uses a dilute phosphoric acid solution with a mass concentration of 3%-10% and the treatment time is 5-15 seconds.

[0011] Further, in step (2), the organic corrosion inhibitor is selected from at least one of benzotriazole, benzimidazole, and 8-hydroxyquinoline, and the organic corrosion inhibitor solution is composed of organic corrosion inhibitor and organic solvent (such as ethanol, acetone, etc.), and the ratio of organic corrosion inhibitor to organic solvent is 3-7g:100ml.

[0012] Furthermore, in step (2), the loading process is carried out under vacuum conditions for 1-3 hours and is repeated 2-5 times.

[0013] Further, in step (3), the catechol compound is dopamine hydrochloride, and the amine compound is polyethyleneimine.

[0014] Further, in step (3), the mass ratio of the amorphous powder loaded with organic corrosion inhibitor to the catechol compound is 1:0.04-0.06, and the mass ratio of the catechol compound to the amine compound is 1:0.8-1.2.

[0015] Further, in step (3), the alkaline buffer solution is a tris(hydroxymethyl)aminomethane buffer solution with pH 8.0-9.0, and the in-situ polymerization reaction is carried out at room temperature for 5-8 hours.

[0016] The present invention provides a double-layer in-situ deposited amorphous powder material prepared according to the above preparation method, comprising: amorphous powder material; an organic corrosion inhibitor layer that penetrates and adheres to the surface and pores of the powder material; and a dense composite polymer organic layer formed by in-situ polymerization of catechol compounds and amine compounds, which coats the powder material and the organic corrosion inhibitor layer.

[0017] Compared with existing technologies, the beneficial effects of this invention are reflected in: 1. A composite pretreatment process of "ultrasonic cleaning + acid etching activation" is adopted, which can efficiently remove impurities from the powder surface and adjust the surface roughness to suit subsequent coating. This process significantly enhances the interfacial bonding between the coating layer and the powder, solves the problem of easy peeling of the coating layer in the prior art, ensures stress transmission, and avoids the attenuation of magnetic core strength.

[0018] 2. The addition of a vacuum loading step for the corrosion inhibitor fills a technological gap in optimizing the internal pores of the powder material. Through multiple impregnation processes under vacuum / inert gas conditions, the corrosion inhibitor fully fills the pores, improving the density of the powder material, reducing stress concentration during core pressing, significantly enhancing the compressive strength of the core, and also improving the inductor's drop resistance.

[0019] 3. By precisely controlling the in-situ polymerization coating process parameters, a composite polymer coating layer with uniform thickness and high coverage is prepared. This coating layer protects the powder particles while strengthening the bonding strength between particles, enabling the magnetic core to form a dense preform. This effectively solves the problem of insufficient strength caused by loose particles, and also provides an effective crack passivation and energy dissipation mechanism for inductor products under impact loads, improving drop resistance.

[0020] 4. Coordinated optimization of various processes has improved drop resistance and magnetic properties. The process design takes into account the protection of the intrinsic magnetic properties of amorphous powder, enabling the product to maintain good magnetic properties while possessing excellent drop resistance and meeting the needs of miniaturized electronic devices. This aligns with the trend of lightweight and high power density development in electronic devices, resulting in a wide range of applications and high practical value. Attached Figure Description

[0021] Figure 1 SEM image of the double-layer in-situ deposited amorphous powder obtained in Example 1; Figure 2 The transmission image is shown for the double-layer in-situ deposited amorphous powder obtained in Example 1. Figure 3 The mechanical strength diagrams of the test toroidal inductors obtained in each embodiment and Comparative Example 1 are shown. Figure 4 The dielectric constant diagrams of the test toroidal inductors obtained in each embodiment and Comparative Example 1 are shown. Figure 5 The resistivity of the coated amorphous powder material in each embodiment and Comparative Example 1 is shown as a function of frequency. Detailed Implementation

[0022] The technical solution of the present invention will be described in detail below through specific embodiments. The following embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0023] Example 1 In this embodiment, a double-layer in-situ deposited amorphous powder material is prepared according to the following steps: Amorphous powder pretreatment: Take 100g of amorphous powder (Fe-Si-BC amorphous powder, with a micron-sized spherical morphology and an average particle size of about 6μm), place it in 200mL of acetone and ultrasonically clean it for 20 minutes. After filtration, immerse it in 5% phosphoric acid solution for etching for 10 seconds. Immediately rinse it with deionized water until neutral, then dehydrate it three times with anhydrous ethanol, and finally dry it at 60℃ under vacuum for 2 hours.

[0024] Benzotriazole (BTA) loading: 30 g of pretreated amorphous powder was dispersed in 100 mL of an ethanol solution containing 3 g of benzotriazole and placed in a vacuum drying oven (-0.10 MPa) for 2 hours. After centrifugation, the solid fraction was dispersed again in 100 mL of an ethanol solution containing 3 g of benzotriazole, and this vacuum adsorption process was repeated 3 times. After centrifugation, the powder was dried at 60 °C for 3 hours to obtain BTA-loaded amorphous powder.

[0025] Polydopamine-polyethyleneimine (PDA-PEI) bilayer deposition: 20 g of the above-mentioned BTA-supported amorphous powder was dispersed in 200 mL of anhydrous ethanol, 1.0 g of dopamine hydrochloride and 1.0 g of polyethyleneimine were added, and the mixture was stirred evenly. Then, 1.2 g of tris(hydroxymethyl)aminomethane was added as a buffer, and the reaction was carried out at room temperature and stirred at 320 r / min for 6 hours. After the reaction was completed, the solid was collected by centrifugation, washed three times with deionized water, and dried at 80 °C under vacuum for 6 hours to obtain the bilayer in-situ deposited amorphous powder material.

[0026] Inductor fabrication and testing: A double-layer in-situ deposited amorphous powder and 2% epoxy resin (by weight of the powder) were added to acetone and stirred thoroughly to allow the acetone to evaporate. The mixture was then passed through an 80-mesh stainless steel sieve and left to stand for 8 hours to remove residual solvent. The material was pressed into a magnetic ring under 10 tons of pressure, and then cured at 180°C for 3 hours to obtain the toroidal inductor for testing.

[0027] Fabrication and Drop Testing of Molded Inductors: A double-layer in-situ deposited amorphous powder and 2% epoxy resin (by weight of the powder) were added to acetone and stirred thoroughly to allow the acetone to evaporate. The mixture was then passed through an 80-mesh stainless steel sieve and left for 8 hours to remove residual solvent. The material was then added to a mold and pressed into a T-Core using 1.5 tons of pressure. Wires were then wound onto the central pillar of the T-Core and molded to obtain a molded inductor. Subsequently, the molded inductor was soldered onto a PCB board using surface mount technology to obtain the molded inductor assembly. Finally, the assembly was bolted to a drop fixture and subjected to a drop test using a free-fall tester.

[0028] Example 2 In this embodiment, a double-layer in-situ deposited amorphous powder material and a toroidal inductor and a one-piece molded inductor for testing were prepared using the same method as in Example 1. The only difference was that the amount of benzotriazole used was 5g when BTA was loaded.

[0029] Example 3 In this embodiment, a double-layer in-situ deposited amorphous powder material and a toroidal inductor and a one-piece molded inductor for testing were prepared using the same method as in Example 1. The only difference was that the amount of benzotriazole used was 7g when BTA was loaded.

[0030] Comparative Example 1 Untreated Fe-Si-BC amorphous powder and 2% epoxy resin (by weight of the powder) were added to acetone and stirred thoroughly to allow the acetone to evaporate. The mixture was then passed through an 80-mesh stainless steel sieve and left to stand for 8 hours to remove residual solvent. The material was pressed into a magnetic ring under 10 tons of pressure and then cured at 180°C for 3 hours to obtain a toroidal inductor for testing.

[0031] Figure 1 The image shows the SEM image of the double-layer in-situ deposited amorphous powder obtained in Example 1. It can be seen that the surface of the amorphous powder is rough, forming a coating layer. After coating, the powder particles are evenly dispersed without serious agglomeration. The particle size after coating is about 6 μm.

[0032] Figure 2 The image shown is a TEM image of the double-layer in-situ deposited amorphous powder obtained in Example 1. It can be seen that the amorphous powder surface is uniformly coated with a coating thickness of about 7 nm.

[0033] Figure 3 The graph shows a comparison of the mechanical strength of the toroidal inductors prepared in each embodiment and the comparative example. As can be seen from the graph, with the increase of the benzotriazole corrosion inhibitor loading, the degree of filling of the internal pores of the amorphous powder gradually increases, and the mechanical strength of the corresponding samples shows a significant increasing trend. Specifically, the mechanical strength of the toroidal inductors prepared in Examples 1, 2, and 3 is increased by 7.7%, 11.3%, and 14.7% respectively compared to Comparative Example 1 (inductor prepared from unmodified amorphous powder), fully demonstrating the technical effect of the present invention in filling internal pores and strengthening the integrity of the magnetic core structure through corrosion inhibitor loading.

[0034] Figure 4 The graph shows the dielectric constant-frequency relationship of the toroidal inductors prepared for testing in each embodiment and comparative example. As can be seen from the graph, the dielectric constant of the samples continuously decreases with increasing benzotriazole corrosion inhibitor loading; and the dielectric constant of all tested samples decreases monotonically with increasing test frequency, consistent with the dielectric characteristics of high-frequency inductor materials. In the high-frequency region (10... 7 The dielectric constants of the samples in Examples 1, 2, and 3 decreased by 3.2%, 15.3%, and 21.5% respectively compared to Comparative Example 1, indicating that the double-layer modified structure of the present invention can effectively reduce the dielectric constant of the magnetic core, which is beneficial to improving the high-frequency stability of inductor components.

[0035] Figure 5 The resistivity-frequency curves of the modified amorphous powder materials in each embodiment and comparative example are shown. Analysis reveals that the resistivity of the samples monotonically increases with increasing benzotriazole corrosion inhibitor loading; simultaneously, the resistivity of all samples monotonically decreases with increasing test frequency. In the high-frequency region (10... 7The resistivity of the samples in Examples 1, 2, and 3 was increased by 127.6%, 233.7%, and 402% respectively compared to Comparative Example 1, which fully demonstrates that the present invention can significantly improve the insulation performance of amorphous powder materials through double-layer in-situ deposition modification, effectively suppress eddy current losses under high-frequency operating conditions, and ensure the electromagnetic performance stability of inductor components.

[0036] Table 1 presents the statistical results of drop reliability tests on the integrally molded inductors prepared in each embodiment and comparative example. The test data clearly show that the introduction of benzotriazole corrosion inhibitor significantly improves the drop resistance of the inductor components: Comparative Example 1 (unmodified sample) showed 3 instances of damage at a drop height of 1.5m, failing the 1.8m drop test; while the modified samples of Examples 1, 2, and 3 showed no damage at drop heights of 1.0m, 1.2m, 1.5m, and 1.8m (damage rate 0%), completely passing the stringent drop resistance test, thus demonstrating the significant effect of the modification technology of this invention in improving the shock resistance and drop reliability of inductors.

[0037] Table 1 Table 2 shows the magnetic performance test results of the toroidal inductors prepared in each embodiment and comparative example (test conditions: 100 kHz, 50 mT). The data in the table show that the overall magnetic performance of the toroidal inductor steadily improves with increasing benzotriazole corrosion inhibitor loading. Specifically, compared to Comparative Example 1 (unmodified sample), Example 3, while maintaining a constant DC bias magnetic field at 80% permeability, exhibits an increase in relative permeability μ from 34.9 to 36.7. Simultaneously, its withstand voltage performance is significantly improved by 135.88%, and its power loss (at 100 kHz, 50 mT) decreases by 2.6%. This fully demonstrates that the double-layer in-situ deposition modification technology of this invention can achieve synergistic optimization of inductor magnetic performance, withstand voltage performance, and loss characteristics while ensuring that the intrinsic magnetic properties of the amorphous powder do not decay.

[0038] Table 2 The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a double-layer in-situ deposited amorphous powder material that can improve the drop resistance of inductors, characterized in that, Includes the following steps: (1) Surface pretreatment: The amorphous powder is cleaned and acid-etched to activate it, and then neutralized, washed, dehydrated and dried to obtain pretreated amorphous powder; (2) Corrosion inhibitor loading: The pretreated amorphous powder is immersed in an organic corrosion inhibitor solution and treated under vacuum or inert atmosphere to load the organic corrosion inhibitor onto the surface and pores of the powder. After post-treatment, the amorphous powder loaded with organic corrosion inhibitor is obtained. (3) In-situ polymerization coating: The amorphous powder loaded with organic corrosion inhibitor is dispersed in an alkaline buffer solution, and catechol compounds and amine compounds are added to carry out an in-situ polymerization reaction to form a composite polymer coating layer on the surface of the powder. The double-layer in-situ deposited amorphous powder is then obtained after post-treatment.

2. The preparation method according to claim 1, characterized in that, In step (1), the acid etching activation treatment uses a dilute phosphoric acid solution with a mass concentration of 3%-10% and the treatment time is 5-15 seconds.

3. The preparation method according to claim 1, characterized in that, In step (2), the organic corrosion inhibitor is selected from at least one of benzotriazole, benzimidazole, and 8-hydroxyquinoline. The organic corrosion inhibitor solution is composed of organic corrosion inhibitor and organic solvent, and the ratio of organic corrosion inhibitor to organic solvent is 3-7g:100mL.

4. The preparation method according to claim 1, characterized in that, In step (2), the loading process is carried out under vacuum conditions for 1-3 hours and is repeated 2-5 times.

5. The preparation method according to claim 1, characterized in that, In step (3), the catechol compound is dopamine hydrochloride and the amine compound is polyethyleneimine.

6. The preparation method according to claim 1 or 5, characterized in that, In step (3), the mass ratio of the amorphous powder loaded with organic corrosion inhibitor to the catechol compound is 1:0.04-0.06, and the mass ratio of the catechol compound to the amine compound is 1:0.8-1.

2.

7. The preparation method according to claim 1 or 5, characterized in that, In step (3), the alkaline buffer solution is a tris(hydroxymethyl)aminomethane buffer solution with pH 8.0-9.0, and the in-situ polymerization reaction is carried out at room temperature for 5-8 hours.

8. A double-layer in-situ deposited amorphous powder material that can improve the drop resistance of inductors, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 7.

9. The double-layer in-situ deposited amorphous powder material according to claim 8, characterized in that, include: Amorphous powder material; an organic corrosion inhibitor layer that penetrates and adheres to the surface and pores of the powder material; And a composite polymer coating layer formed by in-situ polymerization of catechol compounds and amine compounds, which covers the outside of the powder and organic corrosion inhibitor layer.

10. An inductor element, characterized in that, Its magnetic core comprises the amorphous powder material as described in any one of claims 8 to 9.

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