Magnetic material with core-shell structure and preparation method thereof

Abstract

The invention discloses a core-shell structure magnetic material and a preparation method thereof. Comprising a Fe4N core and a Fe2N coating, the Fe2N coating completely wraps the Fe4N core to form Fe4N / Fe2N magnetic particles containing two phases of Fe4N and Fe2N, and the Fe4N core and the Fe2N coating are in continuous transition and are tightly combined through an atomic bond. The preparation method comprises the following steps: nitriding iron powder in a mixed atmosphere of NH3 and H2 at 550 DEG C for 8 hours to obtain a pure Fe4N phase; and nitriding the Fe4N at 500 DEG C in an NH3 atmosphere for 0.1-12 hours, and then cooling the Fe4N to room temperature along with the furnace in a protective atmosphere to obtain the Fe4N / Fe2N core-shell structure particles. And uniformly mixing the Fe4N / Fe2N core-shell structure particles with an adhesive, performing compression molding under the pressure of 1.2 GPa, and then performing stress relief annealing for 2 hours at the temperature of 650 DEG C in a protective atmosphere to obtain the Fe4N / Fe2N core-shell structure magnetic material. The method has the advantages that the Fe4N / Fe2N core-shell structure magnetic material is synthesized in situ, Fe4N and Fe2N phases are tightly combined, the obtained Fe4N and Fe2N phases have excellent insulation characteristics and magnetic performance, and magnetic performance reduction caused by traditional non-magnetic insulation coating is avoided.

Description

technical field

[0001] The invention relates to the field of magnetic material preparation, in particular to a magnetic material with a core-shell structure and a preparation method thereof. Background technique

[0002] Soft magnetic composite materials are formed by uniformly dispersing magnetic particles in non-magnetic materials. Compared with traditional metal soft magnetic alloys and ferrite materials, it has many unique advantages: magnetic metal particles are dispersed in non-conductive objects, which can reduce high-frequency eddy current loss and increase application frequency; it can be processed by hot pressing Powder cores can also be manufactured into complex-shaped magnets by injection molding using current plastic engineering technology; they have the advantages of low density, light weight, high production efficiency, low cost, and good product repeatability and consistency.

[0003] The research work of soft magnetic composite materials mainly focuses on t...

Examples

Embodiment 1

[0037] 1) Raw material preparation

[0038] The raw material is gas atomized iron powder with an average diameter of 37 μm;

[0039] 2) Preparation of Fe by high temperature nitriding 4 N magnetic particles

[0040] Iron powder in NH 3 :H 2 = In a mixed atmosphere of 1:1, nitriding at 550°C for 8 hours to obtain pure Fe 4 N-phase;

[0041] 3) Preparation of Fe by high temperature nitriding 4 N / Fe 2 N core-shell magnetic particles

[0042] The Fe obtained by nitriding 4 N particles, further in NH 3 Nitriding at 400°C for 10 h in the atmosphere, and then cooling to room temperature with the furnace in an argon atmosphere to obtain Fe 4 N / Fe 2 N core-shell magnetic particles.

[0043] 4) Compression molding

[0044] Will Fe 4 N / Fe 2 N core-shell structure magnetic particles are evenly mixed with the binder PVP, and pressed under a pressure of 1.2GPa;

[0045] 5) Stress relief annealing

[0046] The pressed soft magnetic composite material is annealed and heat-treat...

Embodiment 2

[0057] 1) Raw material preparation

[0058] The raw material is gas atomized iron powder with an average diameter of 80 μm;

[0059] 2) Preparation of Fe by high temperature nitriding 4 N magnetic particles

[0060] Iron powder in NH 3 :H 2 = In a mixed atmosphere of 1:1, nitriding at 550°C for 8 hours to obtain pure Fe 4 N-phase;

[0061] 3) Preparation of Fe by high temperature nitriding 4 N / Fe 2 N core-shell magnetic particles

[0062] The Fe obtained by nitriding 4 N particles, further in NH 3 Nitriding at 400°C for 5 hours in the atmosphere, and then cooling to room temperature with the furnace in the nitrogen atmosphere to obtain Fe 4 N / Fe 2 N core-shell magnetic particles.

[0063] 4) Compression molding

[0064] Will Fe 4 N / Fe 2 N core-shell structure magnetic particles are uniformly mixed with adhesive modified epoxy resin, and pressed under 1.2GPa pressure;

[0065] 5) Stress relief annealing

[0066] The pressed soft magnetic composite material is a...

Embodiment 3

[0070] 1) Raw material preparation

[0071] The raw material is gas atomized iron powder with an average diameter of 10 μm;

[0072] 2) Preparation of Fe by high temperature nitriding 4 N magnetic particles

[0073] Iron powder in NH 3 :H 2 = In a mixed atmosphere of 1:1, nitriding at 550°C for 8 hours to obtain pure Fe 4 N-phase;

[0074] 3) Preparation of Fe by high temperature nitriding 4 N / Fe 2 N core-shell magnetic particles

[0075] The Fe obtained by nitriding 4 N particles, further in NH 3 Nitriding at 400°C for 3 hours in the atmosphere, and then cooling to room temperature with the furnace in the nitrogen atmosphere to obtain Fe 4 N / Fe 2 N core-shell magnetic particles.

[0076] 4) Compression molding

[0077] Will Fe 4 N / Fe 2 N core-shell structure magnetic particles are evenly mixed with the binder PVP, and pressed under a pressure of 1.2GPa;

[0078] 5) Stress relief annealing

[0079] The pressed soft magnetic composite material is annealed and h...

technical field

[0001] The invention relates to the field of magnetic material preparation, in particular to a magnetic material with a core-shell structure and a preparation method thereof. Background technique

[0002] Soft magnetic composite materials are formed by uniformly dispersing magnetic particles in non-magnetic materials. Compared with traditional metal soft magnetic alloys and ferrite materials, it has many unique advantages: magnetic metal particles are dispersed in non-conductive objects, which can reduce high-frequency eddy current loss and increase application frequency; it can be processed by hot pressing Powder cores can also be manufactured into complex-shaped magnets by injection molding using current plastic engineering technology; they have the advantages of low density, light weight, high production efficiency, low cost, and good product repeatability and consistency.

[0003] The research work of soft magnetic composite materials mainly focuses on t...

Examples

Embodiment 1

[0037] 1) Raw material preparation

[0038] The raw material is gas atomized iron powder with an average diameter of 37 μm;

[0039] 2) Preparation of Fe by high temperature nitriding 4 N magnetic particles

[0040] Iron powder in NH 3 :H 2 = In a mixed atmosphere of 1:1, nitriding at 550°C for 8 hours to obtain pure Fe 4 N-phase;

[0041] 3) Preparation of Fe by high temperature nitriding 4 N / Fe 2 N core-shell magnetic particles

[0042] The Fe obtained by nitriding 4 N particles, further in NH 3 Nitriding at 400°C for 10 h in the atmosphere, and then cooling to room temperature with the furnace in an argon atmosphere to obtain Fe 4 N / Fe 2 N core-shell magnetic particles.

[0043] 4) Compression molding

[0044] Will Fe 4 N / Fe 2 N core-shell structure magnetic particles are evenly mixed with the binder PVP, and pressed under a pressure of 1.2GPa;

[0045] 5) Stress relief annealing

[0046] The pressed soft magnetic composite material is annealed and heat-treat...

Embodiment 2

[0057] 1) Raw material preparation

[0058] The raw material is gas atomized iron powder with an average diameter of 80 μm;

[0059] 2) Preparation of Fe by high temperature nitriding 4 N magnetic particles

[0060] Iron powder in NH 3 :H 2 = In a mixed atmosphere of 1:1, nitriding at 550°C for 8 hours to obtain pure Fe 4 N-phase;

[0061] 3) Preparation of Fe by high temperature nitriding 4 N / Fe 2 N core-shell magnetic particles

[0062] The Fe obtained by nitriding 4 N particles, further in NH 3 Nitriding at 400°C for 5 hours in the atmosphere, and then cooling to room temperature with the furnace in the nitrogen atmosphere to obtain Fe 4 N / Fe 2 N core-shell magnetic particles.

[0063] 4) Compression molding

[0064] Will Fe 4 N / Fe 2 N core-shell structure magnetic particles are uniformly mixed with adhesive modified epoxy resin, and pressed under 1.2GPa pressure;

[0065] 5) Stress relief annealing

[0066] The pressed soft magnetic composite material is a...

Embodiment 3

[0070] 1) Raw material preparation

[0071] The raw material is gas atomized iron powder with an average diameter of 10 μm;

[0072] 2) Preparation of Fe by high temperature nitriding 4 N magnetic particles

[0073] Iron powder in NH 3 :H 2 = In a mixed atmosphere of 1:1, nitriding at 550°C for 8 hours to obtain pure Fe 4 N-phase;

[0074] 3) Preparation of Fe by high temperature nitriding 4 N / Fe 2 N core-shell magnetic particles

[0075] The Fe obtained by nitriding 4 N particles, further in NH 3 Nitriding at 400°C for 3 hours in the atmosphere, and then cooling to room temperature with the furnace in the nitrogen atmosphere to obtain Fe 4 N / Fe 2 N core-shell magnetic particles.

[0076] 4) Compression molding

[0077] Will Fe 4 N / Fe 2 N core-shell structure magnetic particles are evenly mixed with the binder PVP, and pressed under a pressure of 1.2GPa;

[0078] 5) Stress relief annealing

[0079] The pressed soft magnetic composite material is annealed and h...

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