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Method for reducing irreversible loss of sintered neodymium-iron-boron sheet magnet and increasing use temperature of sintered neodymium-iron-boron sheet magnet

A technology of NdFeB and magnets, which is applied in the manufacture of magnetic objects, magnetic materials, inductors/transformers/magnets, etc., can solve the problems of waste of heavy rare earth elements, difficulty in handling, and smaller grain size, and achieve enhanced anti-magnetization domains Nucleation field, increased use temperature, and reduced direct contact effects

Active Publication Date: 2020-04-10
YANTAI ZHENGHAI MAGNETIC MATERIAL CO LTD +1
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  • Application Information

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Problems solved by technology

However, when the third method is used, when the thickness of the sintered NdFeB sheet magnet drops to 0.6mm, the thickness of the affected layer on both sides is still 72um, accounting for 12% of the total thickness; Its effect gradually declines. When the thickness of sintered NdFeB thin sheet magnets is less than 1mm, its improvement ability is stretched, and as the grain size is further reduced, the difficulty of its manufacturing process is greatly increased, and it is difficult to realize; the fourth method is high-temperature diffusion. Rare earth method, CN 10358633 B or CN104299744 B adopts the method of diffusing heavy rare earth elements to greatly improve the coercive force of sintered NdFeB magnets
Although such patents can effectively improve the coercive force of sintered NdFeB magnets, for such unqualified products to be dealt with in the present invention, it is only necessary to repair the microstructure of the surface of sintered NdFeB magnets to reduce the irreversible loss of products , can transform unqualified products into qualified products, therefore, the method of patent CN 10358633 B or CN 104299744 B will cause waste of expensive heavy rare earth elements, which is inappropriate from the perspective of cost
[0007] In addition, the patent CN 107731437 B also provides a method for reducing the irreversible loss of sintered NdFeB thin sheet magnets by using rotating diffused light rare earth metal Nd, Pr or PrNd alloy quick-setting sheets. There is an unavoidable problem of chipping between the magnets in the furnace. Large chipping will lead to unqualified magnetic flux of the magnet, and small chipping will affect the appearance of the magnet and subsequent assembly. This is a must for industrial magnets with increasingly stringent requirements. to improve
[0008] In addition, the patent CN106783131A provides a method for high and low temperature diffusion treatment of thin-slice magnets such as aluminum foil. intractable problems

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  • Method for reducing irreversible loss of sintered neodymium-iron-boron sheet magnet and increasing use temperature of sintered neodymium-iron-boron sheet magnet
  • Method for reducing irreversible loss of sintered neodymium-iron-boron sheet magnet and increasing use temperature of sintered neodymium-iron-boron sheet magnet
  • Method for reducing irreversible loss of sintered neodymium-iron-boron sheet magnet and increasing use temperature of sintered neodymium-iron-boron sheet magnet

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Effect test

Embodiment 1

[0027] A method for reducing the irreversible loss of a sintered NdFeB thin sheet magnet and increasing its service temperature, the steps are as follows:

[0028] (1) Take the sintered NdFeB thin slice magnet as the original magnet, soak it in 5wt% nitric acid solution for 3s to remove the surface oxide, then ultrasonically clean it with alcohol for 2min, and dry it; wherein, the size of the sintered NdFeB thin slice magnet is 29.7 mm-8.2mm-1.7mm, the direction of thickness 1.7mm is taken as the orientation direction, the parallelism between the upper and lower sides of the thickness direction is 0.05mm, the irreversible loss at 120°C is >10%, and the total amount of rare earth Re is 31.3%;

[0029] (2) According to Nd 35％ Cu 2％ B 0.75％ Fe 62.25％ 1. Preparation of a diffusion source bulk magnet through batching-smelting alloy-crushing-press molding-sintering, the oxygen element O in the obtained magnet = 851ppm, the carbon element C = 667ppm, and the nitrogen element N = 1...

Embodiment 2

[0041] A method for reducing the irreversible loss of a sintered NdFeB thin sheet magnet and increasing its service temperature, the steps are as follows:

[0042] (1) Take the sintered NdFeB sheet magnet as the original magnet, soak it in 6wt% nitric acid solution for 5s to remove the surface oxide, then ultrasonically clean it with alcohol for 2min, and dry it; wherein, the size of the sintered NdFeB sheet magnet is 29.7 mm-8.2mm-1.7mm, the direction of thickness 1.7mm is taken as the orientation direction, the parallelism between the upper and lower sides of the thickness direction is 0.05mm, the irreversible loss at 120°C is >10%, and the total amount of rare earth Re is 31.3%;

[0043] (2) According to Pr 35％ Al 2％ B 0.75％ Fe 62.25％ 1. Preparation of a diffusion source bulk magnet through batching-smelting alloy-crushing-press molding-sintering, the oxygen element O=849ppm in the obtained magnet, the carbon element C=652ppm, and the nitrogen element N=187ppm;

[0044]...

Embodiment 3

[0055] A method for reducing the irreversible loss of a sintered NdFeB thin sheet magnet and increasing its service temperature, the steps are as follows:

[0056] (1) Take the sintered NdFeB sheet magnet as the original magnet, soak it in 3wt% nitric acid solution for 13s to remove the surface oxide, then ultrasonically clean it with alcohol for 2min, and dry it; wherein, the size of the sintered NdFeB sheet magnet is 29.7 mm-8.2mm-1.7mm, the direction of thickness 1.7mm is taken as the orientation direction, the parallelism between the upper and lower sides of the thickness direction is 0.05mm, the irreversible loss at 120°C is >10%, and the total amount of rare earth Re is 31.3%;

[0057] (2) According to Nd 28％ PR 7％ Cu 2％ Al 2％ B 0.72％ Fe 60.28％ 1. Preparation of a diffusion source bulk magnet through batching-smelting alloy-crushing-press molding-sintering, the oxygen element O in the obtained magnet = 833ppm, the carbon element C = 667ppm, and the nitrogen element ...

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Abstract

The invention belongs to the technical field of rare earth permanent magnet materials, and particularly relates to a method for reducing irreversible loss of a sintered neodymium-iron-boron sheet magnet and increasing the use temperature of the sintered neodymium-iron-boron sheet magnet. In the present invention, the sintered neodymium-iron-boron magnet is clamped between large diffusion source magnets (the magnets are in close contact); in the heat treatment process, a neodymium-rich phase in the magnet with higher Re is gasified in a high vacuum state to form metal gas, the metal gas gradually permeates into the surface layer of a sheet blank after forming a layer of film on the surface of the sheet blank, the metal gas permeating into the surface layer of the sheet blank is combined with atoms on the surface layer of the sheet blank to form a new alloy layer, a new grain boundary is constructed, and repairing of the original damaged grain boundary of the sheet blank is achieved; andby means of the repaired grain boundary, direct contact between Nd2Fe14B particles is reduced, the effect of hard magnetic coupling is reduced, a reverse magnetization domain nucleation field on thegrain boundary is enhanced, the low magnetic phenomenon on the surface of a product is improved, then irreversible loss of the magnet is reduced, and the use temperature of the product is increased.

Description

technical field [0001] The invention belongs to the technical field of rare earth permanent magnet materials, and in particular relates to a method for reducing the irreversible loss of a sintered NdFeB sheet magnet and increasing its service temperature. Background technique [0002] NdFeB permanent magnets are the strongest permanent magnets in contemporary times. They not only have excellent characteristics such as high magnetic energy product and high cost performance, but also are easy to process into various sizes. They have been widely used in aviation, aerospace, micro-blog communication technology, electronic , electroacoustic, electromechanical, computing technology, automation technology, automobile industry, petrochemical industry, magnetic separation technology, instrumentation, magnetic medical technology and other devices and equipment that require permanent magnetic fields, especially suitable for the development of high-performance, miniaturized , Lightweigh...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F1/057
CPCH01F41/0253H01F41/0293H01F1/0577
Inventor 彭步庄李广军王帅王娇魏蕊
Owner YANTAI ZHENGHAI MAGNETIC MATERIAL CO LTD