A method for preparing high-performance permanent magnet composite powder

Abstract

This invention discloses a method for preparing high-performance permanent magnet composite powder, belonging to the field of magnetic materials technology. The preparation method includes: manganese (Mn) oxide, bismuth (Bi) oxide, and Sm2Fe oxide of a certain particle size. 17 Alloy powders are mixed in a specific mass ratio and ball-milled in a planetary ball mill under nitrogen protection, followed by ball-milling in a high-energy ball mill jar under nitrogen protection. Simultaneously, reduced CaO powder with a particle size of 10-50 nm is added to the ball mill jar via spraying. The mixed powder is then subjected to a reduction reaction under a low magnetic field-assisted heat treatment in an argon-hydrogen mixed atmosphere, ultimately yielding high-performance MnBi / SmFeN permanent magnet composite powder. This invention features a simple and easy-to-operate process, facilitating the application of high-performance permanent magnet composite powders in a wider range of permanent magnet devices to meet market demands.

Description

Technical Field

[0001] This invention relates to the field of magnetic materials technology, and in particular to a method for preparing high-performance permanent magnet composite powder. Background Technology

[0002] In recent years, with the increasing scarcity and rapid price increases of global rare earth resources, the timely development of a new type of high-magnetic, low-rare-earth permanent magnet is not only a requirement for the development of magnetic products but also a major issue for the sustainable development of my country's rare earth industry. MnBi permanent magnets have advantages such as low cost, corrosion resistance, and good mechanical properties. In particular, their positive temperature coefficient of coercivity within a certain temperature range can compensate for the shortcomings of rare earth permanent magnets. Meanwhile, SmFeN-based permanent magnets have attracted attention since their inception due to their excellent magnetic properties and good temperature stability. As the only permanent magnet that can surpass NdFeB in performance, it has become one of the research hotspots for rare earth permanent magnet materials both domestically and internationally. Therefore, attention has been focused on hybrid magnetic materials containing two hard magnetic phases. Hybrid magnets composed of two hard magnetic phases can combine the advantages of different single-phase permanent magnets, meeting the requirements of modern society for permanent magnet materials. Compared with single-phase magnets, such magnets have the advantages of lower cost and better magnetic properties.

[0003] Therefore, this invention utilizes manganese (Mn) oxide, bismuth (Bi) oxide, and Sm2Fe oxide of a certain particle size. 17 Alloy powders are mixed in a specific mass ratio and ball-milled in a planetary ball mill under nitrogen protection, followed by ball milling in a high-energy ball mill jar under nitrogen protection. Simultaneously, reduced CaO powder with a particle size of 10-50 nm is added to the ball mill jar via spraying. The mixed powder is then subjected to a reduction reaction under a low magnetic field-assisted heat treatment in an argon-hydrogen mixed atmosphere, ultimately yielding high-performance MnBi / SmFeN permanent magnet composite powder. This invention simplifies the process, is easy to operate, has low cost, and is suitable for large-scale mass production. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a method for preparing high-performance permanent magnet composite powder.

[0005] The method for preparing the high-performance permanent magnet composite powder of the present invention includes the following steps:

[0006] (1) Metallic manganese (Mn) oxide, metallic bismuth (Bi) oxide and Sm2Fe with a particle size range of 100~500 μm 17 Alloy powders are mixed in a certain mass ratio and ball-milled in a planetary ball mill under nitrogen protection for 5-10 hours to obtain mixed metal oxide powders.

[0007] (2) The metal oxide mixed powder obtained in step (1) is ball-milled in a high-energy ball mill jar under nitrogen protection for 1 to 5 hours. During the entire ball milling process, reduced powder CaO with a particle size of 10 to 50 nm is added to the ball mill jar by spraying to obtain mixed powder.

[0008] (3) The mixed powder obtained in step (2) is subjected to a reduction reaction in a low magnetic field assisted heat treatment under an argon-hydrogen mixed atmosphere to finally obtain a high-performance permanent magnet composite powder.

[0009] Furthermore, the manganese (Mn) oxide, bismuth (Bi) oxide, and Sm2Fe mentioned in step (1) 17 The mass ratio of the alloy powder is 1:1~1.5:1~3.

[0010] Furthermore, in step (3), the magnetic field strength of the low magnetic field assisted heat treatment is 0.1~1 T, the temperature is 750~850 ℃, the holding time is 1~3 h, and then it is rapidly cooled to room temperature.

[0011] Compared with existing technologies, the present invention has the following advantages and beneficial effects: The present invention uses manganese (Mn) oxide, bismuth (Bi) oxide, and Sm2Fe oxide of a certain particle size. 17 Alloy powders are mixed in a specific mass ratio and ball-milled in a planetary ball mill under nitrogen protection, followed by ball-milling in a high-energy ball mill jar under nitrogen protection. Simultaneously, reduced CaO powder with a particle size of 10-50 nm is added to the ball mill jar via spraying. The mixed powder is then subjected to a reduction reaction under a low magnetic field-assisted heat treatment in an argon-hydrogen mixed atmosphere to obtain high-performance MnBi / SmFeN permanent magnet composite powder. This invention simplifies the process, is easy to operate, has low cost, and is suitable for large-scale mass production. Implementation

[0012] The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments.

[0013] Example 1

[0014] (1) Metallic manganese (Mn) oxide, metallic bismuth (Bi) oxide and Sm2Fe with a particle size range of 500 μm 17 The alloy powders were mixed in a mass ratio of 1:1:1 and ball-milled for 5 h in a planetary ball mill under nitrogen protection to obtain a mixed powder of metal oxides.

[0015] (2) The metal oxide mixed powder obtained in step (1) is ball-milled in a high-energy ball mill jar under nitrogen protection for 1 hour. During the entire ball milling process, reduced powder CaO with a particle size of 50 nm is added to the ball mill jar by spraying to obtain mixed powder.

[0016] (3) The mixed powder obtained in step (2) was subjected to a reduction reaction in a low magnetic field assisted heat treatment under an argon-hydrogen mixed atmosphere. The magnetic field strength was 0.1 T, the temperature was 750 ℃, the holding time was 1 h, and then it was rapidly cooled to room temperature to finally obtain high-performance MnBi / SmFeN permanent magnet composite powder.

[0017] The high-performance MnBi / SmFeN permanent magnet composite powder prepared by the present invention has a coercivity of 13.7 kOe and a magnetic energy product of 11.5 MGOe after magnetic property measurement.

[0018] Example 2

[0019] (1) Metallic manganese (Mn) oxide, metallic bismuth (Bi) oxide and Sm2Fe with a particle size range of 300 μm 17 Alloy powders were mixed in a mass ratio of 1:1.2:2 and ball-milled for 7 h in a planetary ball mill under nitrogen protection to obtain a mixed powder of metal oxides.

[0020] (2) The metal oxide mixed powder obtained in step (1) is ball-milled in a high-energy ball mill jar under nitrogen protection for 3 hours. During the entire ball milling process, reduced powder CaO with a particle size of 30 nm is added to the ball mill jar by spraying to obtain mixed powder.

[0021] (3) The mixed powder obtained in step (2) was subjected to a reduction reaction in a low magnetic field assisted heat treatment under an argon-hydrogen mixed atmosphere. The magnetic field strength was 0.5 T, the temperature was 800 ℃, the holding time was 2 h, and then it was rapidly cooled to room temperature to finally obtain high-performance MnBi / SmFeN permanent magnet composite powder.

[0022] The high-performance MnBi / SmFeN permanent magnet composite powder prepared by the present invention has a coercivity of 14.6 kOe and a magnetic energy product of 13.9 MGOe after magnetic property measurement.

[0023] Example 3

[0024] (1) Metallic manganese (Mn) oxide, metallic bismuth (Bi) oxide and Sm2Fe with a particle size range of 100 μm 17 Alloy powders were mixed in a mass ratio of 1:1.5:3 and ball-milled in a planetary ball mill under nitrogen protection for 10 h to obtain a mixed powder of metal oxides.

[0025] (2) The metal oxide mixed powder obtained in step (1) is ball-milled in a high-energy ball mill jar under nitrogen protection for 5 hours. During the entire ball milling process, reduced powder CaO with a particle size of 10 nm is added to the ball mill jar by spraying to obtain mixed powder.

[0026] (3) The mixed powder obtained in step (2) was subjected to a reduction reaction in a low magnetic field assisted heat treatment under an argon-hydrogen mixed atmosphere. The magnetic field strength was 1 T, the temperature was 850 ℃, the holding time was 3 h, and then it was rapidly cooled to room temperature to finally obtain high-performance MnBi / SmFeN permanent magnet composite powder.

[0027] The high-performance MnBi / SmFeN permanent magnet composite powder prepared by the present invention has a coercivity of 16.8 kOe and a magnetic energy product of 15.2 MGOe after magnetic property measurement.

Claims

1. A method for preparing high-performance permanent magnet composite powder, characterized in that... Includes the following steps: (1) Metallic manganese (Mn) oxide, metallic bismuth (Bi) oxide and Sm2Fe with a particle size range of 100~500 μm 17 Alloy powders are mixed in a certain mass ratio and ball-milled in a planetary ball mill under nitrogen protection for 5-10 hours to obtain mixed metal oxide powders. (2) The metal oxide mixed powder obtained in step (1) is ball-milled in a high-energy ball mill jar under nitrogen protection for 1 to 5 h. During the entire ball milling process, reduced powder CaO with a particle size of 10 to 50 nm is added to the ball mill jar by spraying to obtain mixed powder. (3) The mixed powder obtained in step (2) is subjected to a reduction reaction in a low magnetic field assisted heat treatment under an argon-hydrogen mixed atmosphere to finally obtain a high-performance permanent magnet composite powder.

2. The method for preparing a high-performance permanent magnet composite powder according to claim 1, characterized in that: The manganese (Mn) oxide, bismuth (Bi) oxide, and Sm2Fe mentioned in step (1) 17 The mass ratio of the alloy powder is 1:1~1.5:1~3.

3. The method for preparing a high-performance permanent magnet composite powder according to claim 1, characterized in that: The magnetic field strength of the low magnetic field assisted heat treatment in step (3) is 0.1~1 T, the temperature is 750~850 ℃, the holding time is 1~3 h, and then it is rapidly cooled to room temperature.