Preparation method of double-shell soft magnetic composite material

A soft-magnetic composite material and double-shell technology, which is applied in the fields of inorganic material magnetism, metal material coating process, inductor/transformer/magnet manufacturing, etc., can solve the problems of high saturation magnetic induction intensity and large eddy current loss of soft magnetic composite materials. , to achieve the effect of improving the resistivity of the powder core, reducing the loss, and reducing the magnetic dilution effect

Active Publication Date: 2018-05-22
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing a double-shell soft magnetic composite material. The soft magnetic composite material prepared by the method has the characteristics of low loss, high saturation magnetic induction and good bonding strength, and The cost is low, the operation is simple, and it can solve the problem of large eddy current loss of the existing iron powder core at medium and high frequencies

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  • Preparation method of double-shell soft magnetic composite material
  • Preparation method of double-shell soft magnetic composite material
  • Preparation method of double-shell soft magnetic composite material

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preparation example Construction

[0015] The steps of the preparation method of the double-shell soft magnetic composite material are as follows:

[0016] (1) Select high-purity iron powder with a particle size of 100-400 mesh for particle size ratio and mix. The mass percentage content of the mixed powder is: -100~+200 mesh accounts for 30-40%, and -200~+300 mesh accounts for 30-40% %, -300 mesh accounts for 20-30%, and the rest is -400 mesh;

[0017] (2) Put the iron powder with a good particle size ratio into the furnace, and pass high-purity hydrogen to carry out the reduction reaction. The reduction temperature is 450-600°C, the hydrogen flow rate is controlled at 100-200ml / min, and the reduction time is 1-2h;

[0018] (3) feed the mixed gas of ammonia and hydrogen to carry out surface nitriding, the molar fraction of ammonia in the mixed gas is controlled between 20-60%, the total flow rate of the mixed gas is controlled between 100-300ml / min, the infiltration The nitrogen temperature is 400-650°C, and ...

Embodiment 1

[0025] The iron powder with a purity of 99% is classified into -300 mesh, -200 mesh and -100 mesh and then mixed. 40%, -300 mesh accounted for 20%. The mixed iron powder is put into the quartz tube in the center of the tube furnace, and the hydrogen gas with a purity of 99.999% is introduced to carry out the reduction reaction. The reduction temperature is 500°C, the hydrogen flow rate is 100ml / min, and the reduction time is 2h. A mixed gas of ammonia and hydrogen is introduced for nitriding, the mole fraction of ammonia in the mixed gas is 60%, and the purity of ammonia is 99.98%. The total flow rate of the mixed gas is controlled at 200ml / min, the nitriding temperature is 400°C, and the nitriding time is 2h. After the nitriding process is over, continue to feed the mixed gas of ammonia and hydrogen, and the temperature in the tube furnace will gradually drop to room temperature, forming surface-coated Fe 4 N thin film core-shell structure iron powder. Introduce oxygen wi...

Embodiment 2

[0029]The iron powder with a purity of 99% is classified into -300 mesh, -200 mesh and -100 mesh and then mixed. 30%, -300 mesh accounted for 20%, -400 mesh accounted for 10%. The mixed iron powder is put into the quartz tube in the center of the tube furnace, and the hydrogen gas with a purity of 99.999% is introduced to carry out the reduction reaction. The reduction temperature is 500°C, the hydrogen flow rate is 120ml / min, and the reduction time is 1.5h. A mixed gas of ammonia and hydrogen is introduced for nitriding, the molar fraction of ammonia in the mixed gas is 40%, and the purity of ammonia is 99.98%. The total flow rate of the mixed gas is controlled at 150ml / min, the nitriding temperature is 400°C, and the nitriding time is 1.5h. After the nitriding process is over, continue to feed the mixed gas of ammonia and hydrogen, and the temperature in the tube furnace will gradually drop to room temperature, forming surface-coated Fe 4 N thin film core-shell structure ...

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Abstract

The invention discloses a preparation method of a double-shell soft magnetic composite material. A nitride/oxide double-shell structure is prepared on the surface of high-purity iron powder by a chemical heat treatment process, wherein nitride on the inner layer is used as a transitional layer, and is matched with matrix lattices; and by oxide on the outer layer, the resistivity of an iron power core is further increased on the basis of nitriding, and loss of the iron powder core is reduced favorably. Meanwhile, double shells of nitriding and oxidizing have ferromagnetism, a magnetic dilutioneffect is greatly reduced, and the saturation flux density of the composite material is improved. The preparation method comprises the following key steps: (1) reducing iron powder with a certain particle size ratio in high-purity hydrogen to remove surface oxide; (2) feeding mixed gas of ammonia gas and hydrogen to carry out surface nitriding so as to obtain a Fe4N thin layer on the surface of the iron powder; (3) feeding an oxygen-containing atmosphere to carry out surface oxidizing so as to obtain a double-shell core-shell structure of which the inner shell is Fe4n and the outer shell is Fe3O4; and (4) adding a binder and a lubricating agent in the prepared iron powder, pressing to obtain a soft magnetic composite material and then carrying out vacuum heat treatment.

Description

Technical field: [0001] The invention relates to the technical field of soft magnetic material preparation, in particular to a method for preparing a double-shell soft magnetic composite material. Background technique: [0002] Metal soft magnetic composite material (also known as magnetic powder core) is a kind of soft magnetic material obtained by coating insulating material on the surface of magnetic particles, applying powder metallurgy technology to press the powder into the desired shape, and performing heat treatment and annealing. The magnetic particle size of the metal soft magnetic composite material is small, basically no skin effect occurs, and the stability of the magnetic permeability with frequency is good; the resistivity of the insulating layer is high, which can effectively reduce the eddy current loss between the particles; and the saturation magnetic induction is high, It is beneficial to the miniaturization of devices and is widely used in the field of e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/00B22F1/02B22F3/02B22F3/24C23C8/34H01F1/09H01F41/00
CPCH01F1/09H01F41/00C23C8/34B22F3/02B22F3/24B22F2998/10B22F2003/248B22F1/052B22F1/145B22F1/10
Inventor 吴琛赵敬严密
Owner ZHEJIANG UNIV
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