CN-120809449-B - High-DC bias iron-silicon composite magnetic core for reactor, preparation process and reactor

CN120809449BCN 120809449 BCN120809449 BCN 120809449BCN-120809449-B

Abstract

The application provides a high-DC offset iron-silicon composite magnetic core, wherein the silicon content in the high-DC offset iron-silicon composite magnetic core is not more than 5.5%, the high-DC offset iron-silicon composite magnetic core is coated by an Al2O3/EP nanocomposite material in an insulating manner in the preparation process of the high-DC offset iron-silicon composite magnetic core to form an insulating coating, and the outside of the insulating coating is coated with a parylene coating. The oxygen content of the high-DC bias iron-silicon composite magnetic core is obviously reduced, and the DC bias performance is obviously improved.

Inventors

LIU PENG
CHEN JIAJIAN
HUANG SHANSHAN
SONG ZHIHAI
QIN JIN
HUANG JINPENG
ZENG HAO
LI DINGKANG

Assignees

广东粤海华金科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20250710

Claims (5)

1. The high-DC bias iron-silicon composite magnetic core for the reactor is characterized in that the silicon content in the high-DC bias iron-silicon composite magnetic core is not more than 5.5%; Coating the parylene coating with an aluminum oxide/EP nanocomposite to prepare a composite coating; the high-DC bias iron-silicon composite magnetic core is coated by the composite coating in the preparation process of the high-DC bias iron-silicon composite magnetic core to form an insulating coating; The parylene coating is dispersed with nano zinc oxide particles with the particle diameter of 50-100 nm and the mass ratio of 3-8%; the inside of the magnetic core is provided with gradient silicon content distribution, the silicon content increases from 3wt% to 5.5wt% from the surface of the magnetic core to the center, and the gradient change rate of the silicon content is less than or equal to 0.5wt% per 100 mu m thickness; The high direct current biased ferrosilicon composite magnetic core also comprises ferrocobalt magnetic powder, wherein the weight ratio of the ferrosilicon magnetic powder to the ferrocobalt magnetic powder is 50 (5-50); The rare earth elements of lanthanide series are doped in the ferrosilicon magnetic powder, the rare earth content is gradually decreased from the center of the magnetic core to the surface, the content of the central area is 0.2-0.5wt%, the content of the surface area is 0.01-0.1wt%, and the rare earth elements are distributed at the grain boundary in the form of oxide with the grain diameter less than or equal to 50 nm.
2. A process for preparing a high dc bias ferro-silicon composite magnetic core for a reactor as claimed in claim 1, comprising the steps of: preparing magnetic powder, namely obtaining spherical magnetic powder with the particle size of 10-50 mu m by an aerosol method under the protection of argon atmosphere; Insulating coating, namely preparing a composite coating of the parylene coating coated with nano aluminum oxide/EP, forming a composite insulating layer with the thickness of 0.1-2 mu m on the surface of the spherical magnetic powder through the composite coating by a dry coating or wet coating process; Press molding, namely mixing the coated magnetic powder with zinc stearate lubricant with the mass fraction of 0.5-0.7%, performing cold isostatic pressing in the pressure range of 1800-2500 MPa, and maintaining the pressure for 30-120 seconds to prepare a magnetic core blank with a preset shape; heat treatment, namely heating the formed blank to 500-700 ℃ at 1-5 ℃ per min in a nitrogen-hydrogen mixed atmosphere for annealing treatment, preserving heat for 1-3 hours, and cooling to room temperature along with a furnace; After the magnetic powder preparation step, the method further comprises the step of magnetic powder surface activation treatment: And (3) placing the magnetic powder in a plasma reactor, introducing mixed gas of argon and methane according to the volume ratio of 9:1, and treating at 200-300 ℃ for 30-60 min, wherein a 5-20 nm thick carbon-based transition layer is formed on the surface of the treated magnetic powder.
3. The process for preparing a high dc bias ferro-silicon composite magnetic core for a reactor of claim 2, wherein the annealed magnetic core has a bimodal grain distribution structure in which 50-200 nm fine grains account for 60-80% and 300-500 nm coarse grains account for 20-40%.
4. The process for preparing the high-DC offset ferrosilicon composite magnetic core for the reactor according to claim 2, wherein the magnetic powder preparation comprises ferrosilicon magnetic powder and ferrocobalt magnetic powder, and the weight ratio of the ferrosilicon magnetic powder to the ferrocobalt magnetic powder is 50 (5-50).
5. A reactor comprising the high dc bias ferro-silicon composite magnetic core for a reactor of claim 1.

Description

High-DC bias iron-silicon composite magnetic core for reactor, preparation process and reactor Technical Field The invention relates to the technical field of magnetic materials, in particular to a high-DC bias iron-silicon composite magnetic core for a reactor, a preparation process and the reactor. Background A reactor (also called an inductor) plays a role of filtering in an inverter such as a conventional UPS. The iron core wrapped by the common reactor is made of silicon steel sheet materials and comprises a core column, an upper iron yoke and a lower iron yoke. And the upper iron yoke and the core column, the core column and the core column need to be provided with an air gap plate between the core column and the lower iron yoke to adjust the required inductance value, and the structure leads to complex preparation process and long time consumption. The reactor belongs to a conventional inductor in the electric power field, and plays roles of current limiting, filtering, smoothing, power factor compensation and the like in application scenes. When a short circuit occurs in the power system, a short circuit current with a higher value is generated. Without limitation, it is difficult to maintain dynamic and thermal stability of electrical devices. Therefore, to meet the requirements of certain circuit breaker interruption capacity, reactors are often connected in series at the outlet circuit breaker, increasing the short-circuit impedance and limiting the short-circuit current. Because the reactor is adopted, when short circuit occurs, the voltage drop on the reactor is larger, so that the fluctuation of the bus voltage is smaller, the bus voltage level is maintained, and the running stability of the non-fault line user electrical equipment is ensured. Oxygen content due to oxidation in conventional magnetic core preparation is often higher than 2000ppm, resulting in iron loss exceeding 500 kW/m3. And the DC bias performance is generally lower than 50%, which severely restricts the development of high-frequency power electronic devices. Disclosure of Invention The embodiment of the application solves the technical problem of higher oxygen content in the preparation of the magnetic core in the prior art by providing the high-direct-current bias iron-silicon composite magnetic core for the reactor and the preparation process thereof, effectively reduces the oxygen content of the magnetic core, further reduces the product loss and improves the direct-current bias performance. The first aspect of the application provides a high direct current bias ferro-silicon composite magnetic core, wherein the silicon content in the high direct current bias ferro-silicon composite magnetic core is not more than 5.5%; Coating the Al 2O3/EP nano composite material with a parylene coating to prepare a composite coating; the high-DC bias iron-silicon composite magnetic core is coated by the composite coating in the preparation process to form an insulating coating. In a preferred embodiment, the parylene coating has nano zinc oxide particles dispersed therein, and the particle size is 50-100 nm, and the mass ratio is 3-8%. In a preferred embodiment, the core has a gradient silicon content distribution inside, increasing from 3wt% to 5.5 wt% silicon content from the core surface to the center, and the gradient rate of change of silicon content per 100 μm thickness is 0.5 wt%. In a preferred embodiment, the high DC bias ferrosilicon composite magnetic core further comprises ferrocobalt magnetic powder, wherein the weight ratio of the ferrosilicon magnetic powder to the ferrocobalt magnetic powder is 50 (5-50). In a preferred embodiment, the rare earth elements of lanthanide series are doped in the ferrosilicon magnetic powder, the rare earth content gradually decreases from the center of the magnetic core to the surface, the content of the central area is 0.2-0.5wt%, the content of the surface area is 0.01-0.1wt%, and the rare earth elements are distributed at the grain boundary in the form of oxide with the grain diameter less than or equal to 50 nm. The second aspect of the application provides a preparation process of a high direct current bias iron-silicon composite magnetic core, which comprises the following steps: preparing magnetic powder, namely obtaining spherical magnetic powder with the particle size of 10-50 mu m by an aerosol method under the protection of argon atmosphere; Insulating coating, namely forming a composite insulating layer with the thickness of 0.1-2 mu m on the surface of the spherical magnetic powder through an Al 2O3/EP nano composite material by a dry coating or wet coating process; press molding, namely mixing the coated magnetic powder with 0.5-0.7 wt% of zinc stearate lubricant, performing cold isostatic pressing in the pressure range of 1800-2500 MPa, and maintaining the pressure for 30-120S to prepare a magnetic core blank with a preset shape; And (3) heat treatment, namely heating the fo