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Preparation method of composite magnetic powder

A technology of composite magnetic powder and coarse powder, applied in the field of material science, can solve the problems of affecting saturation magnetization, poor fluidity of molten metal, large melting point temperature difference, etc. Effect

Active Publication Date: 2020-06-05
CHINA JILIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since Mn atoms are easily segregated from the MnBi liquid phase when the peritectic reaction occurs in the MnBi alloy at 719K, it is difficult to obtain pure single-phase MnBi, which directly affects its saturation magnetization.
[0003] Due to the large temperature difference between the melting points of manganese and bismuth and the poor fluidity of the molten metal, the content of low-temperature phases is small. In actual production, long-term (more than 24 hours) low-temperature heat treatment annealing treatment, discharge plasma sintering, etc. are often used to improve the temperature. Low-temperature phase content, while wasting manpower and material resources, still cannot guarantee that the saturation magnetization reaches the ideal value

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] 1) Ingredients: According to the nominal composition Mn 45 Bi 55 , taking Mn and Bi with a purity of more than 99.99% as raw materials for weighing ingredients;

[0018] 2) Smelting: Put the prepared raw materials into the arc melting furnace under the protection of argon by using the arc melting method, and smelting to obtain Mn 45 Bi 55 alloy

[0019] 3) Preparation of coarse powder: the Mn prepared in step 2) 45 Bi 55 Alloy ingots are prepared into coarse powder, and screened through a 100-mesh sieve to obtain coarse powder;

[0020] 4) Assemble the ball mill jar: the Mn obtained in step 3) 45 Bi 55 Take an appropriate amount of alloy powder and put it into a ball mill jar, and add Mn at the same time 45 Bi 55 α-Fe micron powder with 5% mass of alloy coarse powder, put non-magnetic steel balls, add appropriate amount of ethanol, the ball-to-material ratio is 10:1, assemble the ball mill tank and put it into the planetary ball mill;

[0021] 5) Planetary bal...

Embodiment 2

[0033] 1) Ingredients: According to the nominal composition Mn 50 Bi 50 , taking Mn and Bi with a purity of more than 99.99% as raw materials for weighing ingredients;

[0034] 2) Smelting: Put the prepared raw materials into the arc melting furnace under the protection of argon by using the arc melting method, and smelting to obtain Mn 50 Bi 50 alloy

[0035] 3) Preparation of coarse powder: the Mn prepared in step 2) 50 Bi 50 Alloy ingots are prepared into coarse powder, and screened through a 100-mesh sieve to obtain coarse powder;

[0036] 4) Assemble the ball mill jar: the Mn obtained in step 3) 50 Bi 50 Take an appropriate amount of alloy powder and put it into a ball mill jar, and add Mn at the same time 50 Bi 50 α-Fe micron powder with 5% mass of alloy coarse powder, put non-magnetic steel balls, add appropriate amount of ethanol, the ball-to-material ratio is 10:1, assemble the ball mill tank and put it into the planetary ball mill;

[0037] 5) Planetary bal...

Embodiment 3

[0048] 1) Ingredients: According to the nominal composition Mn 55 Bi 45 , taking Mn and Bi with a purity of more than 99.99% as raw materials for weighing ingredients;

[0049] 2) Smelting: Put the prepared raw materials into the arc melting furnace under the protection of argon by using the arc melting method, and smelting to obtain Mn 55 Bi 45 alloy

[0050] 3) Preparation of coarse powder: the Mn prepared in step 2) 55 Bi 45 Alloy ingots are prepared into coarse powder, and screened through a 100-mesh sieve to obtain coarse powder;

[0051] 4) Assemble the ball mill jar: the Mn obtained in step 3) 55 Bi 45 Take an appropriate amount of alloy powder and put it into a ball mill jar, and add Mn at the same time 55 Bi 45 α-Fe micron powder with 5% mass of alloy coarse powder, put non-magnetic steel balls, add appropriate amount of ethanol, the ball-to-material ratio is 10:1, assemble the ball mill tank and put it into the planetary ball mill;

[0052] 5) Planetary bal...

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Abstract

The invention discloses a preparation method of composite magnetic powder. The preparation method comprises the following steps that an alloy ingot is smelted according to the nominal composition MnxBi100-x (mole fraction x = 45, 50, 55), and the alloy ingot is coarsely crushed. According to the preparation method, the prepared MnxBi100-x alloy ingot fragments are put into a mortar to be coarselyground, screening is conducted through a 100-mesh grid sieve after grinding is completed, and the obtained MnxBi100-x alloy powder is subjected to low-energy ball milling compositing; a proper amountof the prepared MnxBi100-x alloy powder is put into a ball milling tank, meanwhile, alpha-Fe micron powder which is 5% of the mass of the MnxBi100-x alloy powder is put, then a proper amount of ethanol and non-magnetic steel balls with proper sizes are added, the ethanol is taken as a ball milling medium, the ratio of the mass of the steel balls to the mass of the MnxBi100-x alloy powder is 10:1,and finally the powder is put into a planetary ball mill; and after the powder is put into the planetary ball mill, the ball milling time is set to be 1-6 hours, the ball milling rotating speed is 256revolutions per minute, and the clockwise / anticlockwise rotating alternating time is 6 minutes, so that the high-saturation magnetization alpha-Fe / MnBi composite magnetic powder is obtained. The process is simple and easy to operate, and the production cost of the high-performance permanent magnet is reduced.

Description

technical field [0001] The invention provides a method for preparing a high-performance α-Fe / MnBi composite magnetic powder, especially a method for preparing a high saturation magnetization α-Fe / MnBi composite magnetic powder by low-energy ball milling, which belongs to the technical field of material science. Background technique [0002] With the rapid development of science and technology, especially in the automotive, aerospace and other fields, there are stricter requirements for various materials under various extreme environmental conditions. As the most important functional material, permanent magnets are increasingly used in the fields of national economy and science and technology. At present, Nd-Fe-B magnets have attracted much attention because of their high magnetic properties and good mechanical properties. However, since the Curie temperature of NdFeB magnets is only 318°C, its working temperature is mostly lower than 200°C, which greatly limits its use at h...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/04C22C12/00H01F41/02
CPCB22F9/04C22C12/00H01F41/0253B22F2009/043
Inventor 吴琼涂元浩泮敏翔葛洪良
Owner CHINA JILIANG UNIV
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