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Flat magnetic powder and preparation method thereof

A magnetic powder, flat technology, applied in the field of flat magnetic powder and its preparation, can solve the problems to be improved, increase energy consumption, reduce production efficiency, etc., to reduce skin effect, reduce flattening time, The effect of improving production efficiency

Active Publication Date: 2013-04-17
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high hardness of this type of alloy, the ball milling time for flattening requires dozens or even hundreds of hours, which greatly increases energy consumption and reduces production efficiency
In addition, the wear resistance and oxidation resistance of this type of alloy need to be improved.

Method used

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  • Flat magnetic powder and preparation method thereof
  • Flat magnetic powder and preparation method thereof
  • Flat magnetic powder and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Using pure iron powder with an average particle size of 40 μm and an average axial ratio of 3 as raw material, add 12 g of iron powder raw material into a stainless steel ball mill tank, use absolute ethanol as a ball mill medium, and mill for 2 hours; the ball milled powder is placed in an oven for After drying, vacuum anneal in a tube furnace for 30 minutes at an annealing temperature of 500°C to eliminate stress and defects caused by ball milling; put the annealed powder back into the tube furnace, and feed high-purity ammonia and high-purity Pure hydrogen gas mixture, control the flow rate of ammonia and hydrogen to 1:1 through the flow meter, the total flow rate is 200ml / min, heat up to 600°C under normal pressure, keep warm for 5 hours, and then cool to room temperature with the furnace to obtain flat Fe 4 N magnetic powder.

[0018] The XRD pattern of the powder that present embodiment makes is as figure 1 As shown, that is, when the raw material is pure iron po...

Embodiment 2

[0020] Using the same pure iron powder as in Example 1 as a raw material, 12g of iron powder raw material was added to a stainless steel ball milling tank, and absolute ethanol was used as a ball milling medium for 30 minutes of ball milling; Vacuum annealing in a tube furnace for 30 minutes at an annealing temperature of 500°C to eliminate the stress and defects caused by ball milling; put the annealed powder back into the tube furnace, and inject a mixture of high-purity ammonia and high-purity hydrogen, The flow rate of ammonia and hydrogen is controlled by a flow meter to be 1:1, the total flow rate is 200ml / min, the temperature is raised to 600°C under normal pressure, and the temperature is kept for 5 hours, then cooled to room temperature with the furnace, and the flat Fe 4 N magnetic powder.

[0021] The phase of the powder obtained in this example is the same as in Example 1, which is pure phase γ'-Fe 4 N; The SEM topography of the powder obtained in this embodiment ...

Embodiment 3

[0023] Take by weighing the Fe that embodiment 1 and embodiment 2 make 4 Each 1.8g of N powder is uniformly mixed with 10wt% paraffin wax after heating and melting; then, press molding on a press to obtain a ring-shaped sample, the pressure used is about 170MPa, the outer diameter of the sample is about 18mm, the inner diameter is about 6mm, and the thickness is about is 3mm; the complex magnetic permeability of the material is measured by a vector network analyzer (Agilent E4991A, US), the test frequency range is 1M~1GHz, and its magnetic spectrum is as follows Figure 4 shown.

[0024] As can be seen from the figure, the cutoff frequency (corresponding to the maximum value of the imaginary part of the magnetic permeability) of the sample corresponding to Example 2 is about 23MHz, while the corresponding cutoff frequency of Example 1 is significantly improved, about 100MHz, and the permeability The real part and imaginary part are also higher than that of Embodiment 2 in mos...

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Abstract

The invention belongs to the technical field of magnetic powder and relates to flat magnetic powder and a preparation method thereof. The main phase of the magnetic powder is gamma'-Fe4N, the thickness of the powder is 0.1-9 micrometers, and the radium-thickness ratio is 10-200. The method includes: taking pure iron powder lower in hardness as a raw material, adopting the ball-milling method for flattening treatment, nitriding in a gas mixture of ammonia / hydrogen, and controlling technical parameters such as the thickness and the flatness of the powder by adjusting process conditions such as grain size and ball-milling time of the powder to realize control on electromagnetic performances such as cutoff frequency of the powder. The flat magnetic powder effectively reduces skin effect of a Fe4N material and is in favor of high-frequency application of the Fe4N material, and the preparation method is simple, flattening time is substantially lowered, production efficiency is improved, and control on micro-topography and the electromagnetic performances of the powder can be realized.

Description

technical field [0001] The invention relates to a flat magnetic powder with controllable microscopic appearance and properties and a preparation method thereof, belonging to the technical field of magnetic powder preparation. Background technique [0002] With the development of electronic, electrical and information communication technologies, soft magnetic materials are used more and more widely, especially in various transformers, inductance components, filter devices and other application fields. At present, soft magnetic metals represented by iron and their alloy materials play an irreplaceable role in some of the above-mentioned application fields due to their extremely high magnetic permeability and saturation magnetic induction. However, due to the low resistivity of this type of material, the magnet will produce serious eddy current loss and skin effect in the alternating magnetic field. The actual demand for the development of high frequency. On the other hand, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/147H01F1/20B22F1/00
Inventor 瞿志学王群孙忠巍王澈李永卿唐章宏
Owner BEIJING UNIV OF TECH
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