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A method for reducing the irreversible loss of sintered NdFeB thin slice magnets and increasing their service temperature

A neodymium-iron-boron and magnet technology, which is applied in the manufacture of magnetic objects, magnetic materials, inductors/transformers/magnets, etc., can solve the problems of intractability, waste of heavy rare earth elements, and difficulty in process manufacturing, and achieves simple formulation and low cost. Effect

Active Publication Date: 2022-01-28
YANTAI ZHENGHAI MAGNETIC MATERIAL CO LTD +1
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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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  • A method for reducing the irreversible loss of sintered NdFeB thin slice magnets and increasing their service temperature
  • A method for reducing the irreversible loss of sintered NdFeB thin slice magnets and increasing their service temperature
  • A method for reducing the irreversible loss of sintered NdFeB thin slice magnets and increasing their service temperature

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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 in particular relates to a method for reducing the irreversible loss of a sintered NdFeB sheet magnet and increasing its service temperature. In the present invention, the sintered NdFeB magnet is sandwiched between the diffusion source bulk magnets (close contact between the magnets), and during the heat treatment process, the neodymium-rich phase in the magnet with higher Re is gasified in a high vacuum state Forming metal gas, the metal gas forms a layer of film on the surface of the sheet blank and gradually penetrates into the surface layer of the sheet blank, and the metal gas that penetrates into the surface layer of the sheet blank combines with the surface atoms of the sheet blank to form a new alloy layer and build a new grain boundary, Realize the repair of the original damaged grain boundary of the sheet blank; the repaired grain boundary reduces Nd 2 Fe 14 The direct contact between B particles reduces the effect of hard magnetic coupling, enhances the anti-magnetization domain nucleation field on the grain boundary, improves the low magnetic phenomenon on the surface of the product, reduces the irreversible loss of the magnet, and increases the service temperature of the product.

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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Patent Type & Authority Patents(China)
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