CN-122025329-A - FeNi soft magnetic composite material based on n-butyl silicate hydrolytic cladding and preparation method thereof

Abstract

The invention discloses a FeNi soft magnetic composite material based on hydrolysis cladding of butyl orthosilicate and a preparation method thereof. According to the method, siO 2 gel is generated by utilizing hydrolysis of butyl orthosilicate through a controllable sol-gel process, then a uniform and ultrathin SiO 2 gel layer is generated on the surface of FeNi powder in situ, and then the SiO 2 insulating coated FeNi soft magnetic composite material is obtained through densification by heat treatment. The SiO 2 insulating layer is firmly combined with the matrix metal powder, has good thermal stability, and greatly reduces the dilution of nonmagnetic relative magnetic performance while realizing high-frequency high resistivity. The final magnetic core is obtained through compression molding and annealing heat treatment, has excellent characteristics of high effective magnetic permeability and low high-frequency magnetic core loss, and is particularly suitable for various high-efficiency and miniaturized power electronic devices in MHz frequency band.

Inventors

• ZHANG XUEFENG
• ZHANG ERPAN
• CAO QIAN

Assignees

• 杭州电子科技大学

Dates

Publication Date

20260512

Application Date

20260311

Claims (10)

1. 1. A FeNi soft magnetic composite material based on hydrolysis cladding of butyl orthosilicate is characterized by comprising FeNi particles and a compact SiO 2 insulating layer cladding FeNi, wherein the mass fraction of the SiO 2 insulating layer is 0.2-1.5wt%, the effective magnetic permeability mu e of the material at 1MHz frequency is above 100, and the magnetic core loss under 1MHz and 50mT test conditions is not more than 1000mW/cm 3 .
2. 2. A preparation method of FeNi soft magnetic composite material based on hydrolysis cladding of butyl orthosilicate is characterized in that butyl orthosilicate is mixed with absolute ethyl alcohol and deionized water containing a catalyst to prepare SiO 2 precursor sol; The preparation method comprises the steps of weighing FeNi alloy powder, dispersing the FeNi alloy powder in an ethanol solvent to obtain FeNi alloy powder suspension, slowly dripping SiO 2 precursor sol into the FeNi alloy powder suspension, controlling the temperature to be 30-60 ℃, carrying out hydrolysis-condensation reaction under the catalysis condition to enable SiO 2 gel to be coated on the surface of the FeNi powder, standing for aging, carrying out solid-liquid separation, drying at low temperature, then carrying out heat treatment to enable the SiO 2 gel layer to be converted into a compact insulating layer, and obtaining the FeNi soft magnetic composite material, wherein the mass fraction of the SiO 2 insulating layer is 0.2-1.5 wt%.
3. 3. The preparation method of the FeNi soft magnetic composite material based on the hydrolysis coating of the butyl orthosilicate is characterized in that the mol ratio of TBOS to absolute ethyl alcohol to deionized water to catalyst is 1 (4-8): 4-6): 0.01-0.1.
4. 4. The preparation method of the FeNi soft magnetic composite material based on the hydrolysis coating of the butyl orthosilicate is characterized in that the volume ratio of ethanol to water in the ethanol solvent is (2-4): 1.
5. 5. The method for preparing the FeNi soft magnetic composite material based on the hydrolysis coating of the butyl orthosilicate, which is characterized in that the mass fraction of the SiO 2 insulating layer is 0.5-1.0 wt%, and the mass fraction of the SiO 2 insulating layer is controlled by adjusting the duty ratio of TBOS in SiO 2 precursor sol.
6. 6. The preparation method of the FeNi soft magnetic composite material based on the hydrolysis cladding of the butyl orthosilicate is characterized in that the set heat treatment temperature is 450-550 ℃.
7. 7. The application of the FeNi soft magnetic composite material based on the butyl orthosilicate hydrolytic cladding is characterized in that the FeNi soft magnetic composite material based on the butyl orthosilicate hydrolytic cladding as set forth in claim 1 or prepared by any one of the methods as set forth in claims 2-6 is used for preparing MHz frequency band power inductors, transformers or EMI filters.
8. 8. The method according to claim 7, wherein the FeNi soft magnetic composite material is mixed with an organic insulating binder, pressed into a magnetic core of a desired shape under high pressure, and annealed in a protective atmosphere.
9. 9. The application of the FeNi soft magnetic composite material based on the hydrolysis cladding of the butyl orthosilicate as claimed in claim 8, wherein the organic insulating binder is silicon resin or epoxy resin, and the addition amount is not more than 0.5 wt% of the total mass of the FeNi soft magnetic composite material.
10. 10. The application of the FeNi soft magnetic composite material based on the hydrolysis cladding of butyl orthosilicate, which is disclosed in claim 8, is characterized in that the annealing temperature is 600-800 ℃.

Description

FeNi soft magnetic composite material based on n-butyl silicate hydrolytic cladding and preparation method thereof Technical Field The invention belongs to the technical field of electronic materials, relates to a soft magnetic composite material and a preparation method thereof, and in particular relates to a FeNi soft magnetic composite material based on hydrolysis cladding of butyl orthosilicate (TBOS) and a preparation method thereof. Background Under high frequency conditions, the eddy current loss of the soft magnetic composite material increases dramatically with increasing frequency. The silicon oxide layer is coated on the surface of the magnetic metal powder by adopting a sol-gel method, so that the resistivity, the thermal stability and the oxidation resistance can be improved, the low magnetic loss of the soft magnet under high frequency is realized, and the high-frequency, miniaturization and high-efficiency development requirements of the power electronic technology are met. The TEOS hydrolysis process is a common method for preparing the SiO 2 coating, has the advantages of uniform film formation, controllable thickness, pure components and the like, has lower conductivity of SiO 2, and can effectively reduce the dielectric constant and dielectric loss of the electromagnetic material. However, TEOS does not contain a strong polar group, so that the bonding strength between TEOS and the surface of the metal particles is low, and the coating structure is sparse. And part of the method coats SiO 2 on the surfaces of materials such as iron powder, carbonyl iron powder Fe (CO) 5 and the like to obtain a soft magnetic composite material, but because the physical properties of the SiO 2 coating and internal metal particles are greatly different, cracks or falling off easily occur in the subsequent pressing and annealing heat treatment, the heat treatment temperature cannot be over 600 ℃, and the resistivity of the material is low, so that the material has large eddy current loss and cannot be applied to devices with high frequency (MHz). In summary, the prior art lacks a scheme capable of improving the interface bonding strength between the insulating layer and the metal material and synergistically optimizing the high-frequency magnetic performance of the soft magnetic composite material. Disclosure of Invention Aiming at the defects of the prior art, the invention provides the FeNi soft magnetic composite material based on the hydrolysis cladding of the butyl orthosilicate and the preparation method thereof, and a layer of uniform, compact, ultrathin and firmly-combined SiO 2 insulating layer is grown on the surface of FeNi powder in situ by controlling the hydrolysis process of TBOS, so that the high-frequency eddy current loss of the material is remarkably reduced, and meanwhile, the excellent soft magnetic characteristics such as high magnetic conductivity and the like are maintained to the maximum extent. A FeNi soft magnetic composite material based on hydrolysis cladding of butyl orthosilicate is characterized in that a compact SiO 2 insulating layer with the thickness of 5-30 nm is clad on the surface of FeNi particles, and the mass fraction of the SiO 2 insulating layer is 0.2-1.5wt%. The effective magnetic permeability mu e of the material under the frequency of 1MHz is more than 100, and the magnetic core loss under the test conditions of 1MHz and 50mT is not more than 1000mW/cm 3. A preparation method of FeNi soft magnetic composite material based on hydrolysis cladding of butyl orthosilicate specifically comprises the following steps: and step 1, cleaning and drying the FeNi alloy powder to remove surface grease and oxides. Step 2, mixing butyl orthosilicate (TBOS) with absolute ethyl alcohol, slowly dropwise adding deionized water containing a catalyst under the stirring condition, and continuously stirring to form uniform and transparent SiO 2 precursor sol. The mol ratio of TBOS, absolute ethyl alcohol, water and catalyst is 1 (4-8): (4-6): (0.01-0.1). And step 3, dispersing the pretreated FeNi alloy powder in an ethanol solvent to obtain FeNi alloy powder suspension. The volume ratio of ethanol to water in the ethanol solvent is (2-4): 1. Slowly dropwise adding the SiO 2 precursor sol into FeNi alloy powder suspension, controlling the temperature to be 30-60 ℃, and carrying out hydrolysis-condensation reaction for 2-6 hours under the catalysis condition to coat the SiO 2 gel layer on the surface of the FeNi powder. And 4, standing and aging the coated powder system, then carrying out solid-liquid separation, and drying the obtained powder at a low temperature to obtain FeNi powder with the SiO 2 gel coated on the surface. And 5, carrying out heat treatment on FeNi powder coated with SiO 2 gel on the surface in inert atmosphere or vacuum, wherein the temperature is 300-600 ℃, and the heat preservation time is 0.5-2 hours, so that the SiO 2 gel layer is converted into a compact insul