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Double-layer inorganic insulation coated soft magnetic powder and preparation method thereof

A technology of inorganic insulation and soft magnetic powder, which is applied in the fields of magnetism of inorganic materials, permanent magnet manufacturing, inductor/transformer/magnet manufacturing, etc. It can solve the problem of poor interfacial bonding of the coating layer, insufficient compactness of the coating layer, and decreased insulation performance, etc. problems, to achieve the effect of wide applicability, good chemical wettability and high resistivity

Active Publication Date: 2019-07-05
GUANGDONG INST OF NEW MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, its main disadvantages are that the coating layer is not dense enough, the insulation performance is reduced under high voltage, the interface bonding of the coating layer is poor, and it is easy to break and fall off during the pressing and molding process, causing the insulation performance to decline or even fail.

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  • Double-layer inorganic insulation coated soft magnetic powder and preparation method thereof
  • Double-layer inorganic insulation coated soft magnetic powder and preparation method thereof
  • Double-layer inorganic insulation coated soft magnetic powder and preparation method thereof

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preparation example Construction

[0030] On the other hand, the embodiment of the present application also provides a method for preparing a double-layer inorganic insulating coated soft magnetic powder, the method comprising the following steps:

[0031] S1. Carry out in-situ oxidation coating on the magnetic powder.

[0032] Put a certain amount of metal magnetic powder in the reactor, heat it to 100-500°C under the first inert fluidizing gas, and pass it into an oxidizing atmosphere for in-situ oxidation. The oxidation time is 1-60min, forming a coating on the outer surface of the magnetic powder transition oxide layer.

[0033] In the present application, the inlet velocity of the first inert fluidizing gas is 2-5 times of the fluidizing gas velocity (that is, the lowest gas velocity that can make the materials in the reactor fluidized).

[0034] Preferably, before the in-situ oxidation of the magnetic powder, the metal magnetic powder can also be reduced first, that is, before the oxidation atmosphere is...

Embodiment 1

[0057] This embodiment provides a double-layer inorganic insulating coated soft magnetic powder (Fe-6.5Si / FeOx / alumina) and a preparation method thereof.

[0058] 40g, 150-mesh Fe-6.5Si magnetic powder was stirred and cleaned with ethanol and acetone, respectively, for 15 minutes each time, and then dried at 70°C for 2 hours. Such as figure 1 and figure 2 As shown, Fe-6.5Si is spherical or nearly spherical, with a smooth surface. Put the cleaned Fe-6.5Si magnetic powder in the fluidized bed reactor, the first inert fluidizing gas N at 3 times the fluidizing gas velocity 2 Heating to 300°C under protection, in reducing atmosphere N 2 -H 2 (1:1) reduction for 15min, then feed pure N into the reactor for 10min 2 to drive away the reducing atmosphere, and then in the oxidizing atmosphere N 2 / O 2 (4:1) in-situ oxidation for 20 minutes to form a transition oxide layer with a thickness of 45 nm. Such as image 3 As shown, the surface of the powder becomes rough after in-si...

Embodiment 2

[0060] This embodiment provides a double-layer inorganic insulating coated soft magnetic powder (Fe / FeOx / silicon oxide) and a preparation method thereof.

[0061] 40g, 150mesh Fe magnetic powder was stirred and washed once with water and acetone respectively, each time for 15min, and then dried at 55°C for 3h. Fe is spherical or nearly spherical, with a smooth surface. Put the cleaned Fe magnetic powder in a fluidized bed reactor, and heat it to 200°C under the protection of the first inert fluidizing gas Ar gas at twice the fluidizing gas velocity, and in the reducing atmosphere Ar gas-H 2 (1:2) reduction for 15min, then into the reactor for 10min pure Ar gas to drive away the reducing atmosphere, and then in the oxidizing atmosphere Ar gas / O 2 (1:2) in-situ oxidation for 30 minutes to form a transition oxide layer with a thickness of 20 nm. After in-situ oxidation, the surface of the powder becomes rough, and a large number of nanoscale protrusions are formed. Then, the s...

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Abstract

The invention provides double-layer inorganic insulation coated soft magnetic powder and a preparation method thereof, and relates to the field of metal soft magnetic composite materials. The double-layer inorganic insulation coated soft magnetic powder comprises magnetic powder and a transition oxide layer and a dense oxide layer which sequentially coat the outer surface of the magnetic powder from inside to outside, wherein the transition oxide layer is formed by performing in-situ oxidation on the surface of the magnetic powder, so that the bonding strength of the magnetic powder and the transition oxide layer is high, and meanwhile, an interface between the transition oxide layer and the dense oxide layer has good chemical wettability and high bonding strength; the dense oxide layer isformed on the surface of the transition oxide layer through chemical vapor deposition, the coating compactness is good, the resistivity is high, and the insulating property under the high voltage isgood.

Description

technical field [0001] The invention relates to the field of metal soft magnetic composite materials, in particular to a double-layer inorganic insulation coated soft magnetic powder and a preparation method thereof. Background technique [0002] Metal soft magnetic composites (SMCs, also known as magnetic powder cores) are a kind of Fe-based alloy, amorphous or nanocrystalline magnetic powder as raw materials, after the surface of the particles is coated with an insulating medium, it is pressed into the desired shape by powder metallurgy. It is a new type of soft magnetic functional material obtained by heat treatment and annealing. Among them, insulation coating is the key link, which plays a decisive role in improving the overall resistivity of SMCs, blocking the eddy current between particles, reducing the high-frequency eddy current loss of SMCs, and improving the comprehensive electro-magnetic properties. Generally speaking, there are many requirements for the insulat...

Claims

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Application Information

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IPC IPC(8): H01F1/33H01F41/02
CPCH01F1/33H01F41/0253H01F41/026
Inventor 雷超王健刘辛
Owner GUANGDONG INST OF NEW MATERIALS