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Sendust/ferrite composite magnetic powder and preparation method of magnetic powder core adopting same

A technology of sendust and ferrite, which is applied in the field of material preparation, can solve problems such as improving magnetic permeability, low core loss, and unstable strength of the insulating layer, so as to improve magnetic permeability and resistivity, and reduce high frequency Eddy current loss, the effect of overcoming the instability of the insulating layer

Inactive Publication Date: 2017-01-25
GUANGDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Chinese patent CN201210443610.X discloses a preparation process of a high magnetic flux density and low core loss sendust magnetic powder core. The target is obtained through steps such as powder selection, pretreatment, passivation treatment, insulation coating treatment, compression molding, and heat treatment. The prepared product has high magnetic permeability and low core loss, but the steps are relatively complicated
This kind of mechanical mixing is difficult to ensure the continuity of the ferrite insulating layer, and it is also difficult to completely block the electrical contact between the soft magnetic alloy particles.
[0007] Chinese patent CN103426580.A discloses a composite magnetic powder core and its preparation method. Ferrite particles are prepared in situ on the surface of soft magnetic alloy powder by hydrothermal method. Although the continuity of the ferrite insulating layer is improved, the method Only the soft magnetic alloy is passivated, not flattened, which is not conducive to reducing the high-frequency loss of the magnetic powder core and improving the magnetic permeability.
[0008] In summary, the insulation coating process used in the preparation methods of sendust magnetic powder cores commonly used at home and abroad at present, the non-magnetic insulating layer used dilutes the magnetism, resulting in low magnetic permeability, unstable insulating layer (pyrolysis) and low strength (magnetic powder The cladding layer is easily crushed during the core compression molding process) resulting in high frequency loss
In addition, the currently commonly used sendust magnetic powder is not flat enough, which is not conducive to further improving the magnetic permeability and reducing high-frequency loss

Method used

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preparation example Construction

[0024] The invention provides a method for preparing sendust / ferrite composite magnetic powder, comprising the following steps:

[0025] 1) Iron, silicon, and aluminum raw materials are made into a sendust strip of standard composition, which is then crushed and ball-milled to obtain flat sendust magnetic powder; the Fe 3+ , Zn 3+ and Mn 2+ The nitrate is fully dissolved in deionized water to obtain Fe-Zn-Mn mixed nitrate solution;

[0026] 2) Add a corresponding amount of the sendust magnetic powder into the Fe-Zn-Mn mixed nitrate solution according to the coating amount (theoretical calculation value) of ferrite in the sendust / ferrite composite magnetic powder, at 120 Conduct hydrothermal reaction at ℃~220℃ for 5h~11h, add NaOH solution, adjust the pH value to 8~12, generate manganese zinc ferrite on the surface of sendust magnetic powder in situ, wash and dry in turn to obtain iron silicon Aluminum / ferrite composite magnetic powder.

[0027] In the preparation method of...

Embodiment 1

[0041] In this embodiment, the composition of the sendust magnetic powder is Si: 9.6 wt%, Al: 5.4 wt%, and the rest is Fe.

[0042] 1) Using an induction-type melt quenching device, in a directional magnetic field of 1000Oe, iron, silicon, and aluminum raw materials are made into iron-silicon-aluminum alloy strips with standard components, then crushed, and placed in a ball mill for high-energy ball milling, wherein, The ball-to-material ratio is 12:1, and the ball mill is 40h to obtain flattened sendust magnetic powder; Fe 3+ , Zn 3+ and Mn 2+ of nitrates as raw materials, according to Fe 3+ , Zn 2+ and Mn 2+ The mol ratio is 10:3:2 weighing, adding deionized water to fully dissolve, obtain Fe-Zn-Mn mixed nitrate solution;

[0043] 2) The sendust magnetic powder is added to the mixed nitrate solution according to the mass ratio of manganese zinc ferrite and sendust magnetic powder at a mass ratio of 6%, and the pH value is adjusted to 10 with a NaOH solution having a con...

Embodiment 2

[0053] In this embodiment, the composition of the sendust magnetic powder is Si: 9.6 wt%, Al: 5.4 wt%, and the rest is Fe.

[0054] 1) Using an induction-type melt quenching device, in a directional magnetic field of 1000Oe, iron, silicon, and aluminum raw materials are made into iron-silicon-aluminum alloy strips with standard components, then crushed, and placed in a ball mill for high-energy ball milling, wherein, The ball-to-material ratio is 12:1, and the ball mill is 40h to obtain flattened sendust magnetic powder; Fe 3+ , Zn 3+ and Mn 2+ of nitrates as raw materials, according to Fe 3+ , Zn 2+ and Mn 2+ The mol ratio is 10:3:2 weighing, fully dissolved in deionized water, obtain Fe-Zn-Mn mixed nitrate solution;

[0055] 2) The sendust magnetic powder is added to the mixed nitrate solution according to the mass ratio of manganese zinc ferrite and sendust magnetic powder at a mass ratio of 6%, and the pH value is adjusted to 10 with a NaOH solution having a concentra...

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PUM

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Abstract

The invention relates to the field of material preparation, in particular to sendust / ferrite composite magnetic powder and a preparation method of a magnetic powder core adopting the same. The preparation method comprises the following steps: firstly, flat sendust magnetic powder is prepared, then, the sendust magnetic powder is put in a Fe-Zn-Mn mixed nitrate solution, a ferrite coating is synthesized in situ on the surface of the flat sendust magnetic powder through a hydrothermal reaction, the ferrite coating is washed, dried and mixed with a binder and a lubricant, the magnetic powder core is prepared from the sendust / ferrite composite magnetic powder through cold pressing, and then stress relief annealing is performed. The sendust / ferrite composite magnetic powder and magnetic powder core have high magnetic conductivity and low high-frequency loss, and can be applied to telecommunications and radar as well as fields of microwave absorption and electromagnetic shielding.

Description

technical field [0001] The invention belongs to the field of material preparation, and in particular relates to a method for preparing sendust / ferrite composite magnetic powder and its magnetic powder core. Background technique [0002] Sendust soft magnetic alloy, also known as Sendust alloy, has a chemical composition of 5.4wt.% Al, 9.6wt.% Si, and the rest is Fe (85wt.%). Sensil is very brittle and is easily broken into powder. It is generally prepared as a magnetic powder core for use. [0003] Compared with iron-silicon cores and iron powder cores, sendust magnetic powder cores have lower high-frequency loss, and have higher saturation magnetic induction and magnetic permeability, and are inexpensive, which is conducive to miniaturization. In addition, the magnetostriction coefficient λ of sendust s Close to zero, it is beneficial to eliminate the auditory frequency noise generated when the filter inductor is working. Due to the characteristics of low loss, low cost,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/33H01F41/02
CPCH01F41/0246H01F1/33
Inventor 何玉定杨元政谢致薇陈先朝
Owner GUANGDONG UNIV OF TECH
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