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Method for preparing rolling anisotropic magnetic powder and magnet

An anisotropic magnetic and anisotropic technology, applied in the direction of magnetic objects, magnetic materials, inorganic materials, etc., can solve the problem of poor corrosion resistance of NdFeB, no rolling anisotropy, large powder particle size, etc. question

Active Publication Date: 2008-11-26
NINGXIA MAGVALLEY NOVEL MATERIALS TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the rapid quenching NdFeB magnetic powder has encountered some problems in the manufacture of rolled magnets. Because of the large particle size of the powder, it has poor flexibility, rough surface, and the magnetic powder is easy to fall off from the magnet. Making calendered magnets adds to the difficulty
And the quick-quenched NdFeB magnetic powder is isotropic and does not have calendering anisotropy
As for the anisotropic rare earth permanent magnet materials such as samarium cobalt and HDDR (Hydrogenation hydrogenation, Disproportionation disproportionation, Desorption dehydrogenation, Recombination recombination) NdFeB magnetic powder with texture, in fact, this anisotropy It refers only to the magnetic crystal anisotropy, that is, the magnetic powder can be oriented under the action of a magnetic field. Anisotropic molded or anisotropic injection magnets can be prepared by using magnetic field forming technology, but they do not have calendering anisotropy. The calendered rubber magnets produced are Isotropic, such as samarium cobalt magnetic powder, although it has high performance, but because there is no rolling anisotropy, the maximum energy product of the prepared rolling magnet is low, so it cannot be used commercially
In order to meet the requirements of device miniaturization, it is necessary to develop various types of high-performance anisotropic rare earth bonded magnets, especially anisotropic flexible calendered rubber magnets, but there is no rare earth permanent magnet material that can meet this requirement at the same time.

Method used

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  • Method for preparing rolling anisotropic magnetic powder and magnet
  • Method for preparing rolling anisotropic magnetic powder and magnet
  • Method for preparing rolling anisotropic magnetic powder and magnet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Composition is Nd 7.7 Fe 80.8 V 11.0 Si 0.5 , the master alloy was prepared by quick-setting thin sheet technology, and then heat-treated in a nitrogen atmosphere at 500 ° C, the nitrogen pressure was 0.1Mpa, and kept for 4 hours, and the corresponding nitride was formed through a gas-solid phase reaction, and its composition was Nd 6.7 Fe 75.1 V 9.8 Si 0.4 N 8.0 , The nitrides are developed into micropowders by using a ball mill, and the magnetic powders of different particle sizes are formed by controlling the ball milling time. Table 3 shows that the magnetic powder properties vary with the particle size of the magnetic powder.

[0046] Table 3.Nd 6.7 Fe 75.1 V 9.8 Si 0.4 N 8.0 The change of permanent magnetic properties of magnetic powder with the particle size of magnetic powder

[0047] Average particle size of magnetic powder (μm)

Embodiment 2

[0049] Calculated by weight percentage, according to the following formula to prepare rolling magnets: Nd 7.1 Fe 80.8 V 11.04 Si 0.46 N 8.8 Magnetic powder 93%, coupling agent 0.8%, chlorinated polyethylene (CPE) 5.4%, epoxy derivative plasticizer 0.3%, ketamine compound antioxidant 0.5%. The average particle size of the magnetic powder is 2.1 microns. The above materials were prepared and fully mixed, and then the mixture was added into an open mill for mixing. The temperature of the rolls of the open mill was 50° C., and the preheating time was 150 minutes. The roll speed ratio of the front and rear rolls is 1.15:1, and the roll distance is 0.3mm. When all the powders used are bonded into a whole, the mixing is considered to be over. The kneaded material is rolled. A flat rolled magnet was produced. The roll speed ratio of the front and rear rolls is 1:1, and the roll distance is 0.5 mm. The compression ratio is 4:1, and then the roller distance is adjusted to compr...

Embodiment 3

[0053] Completely follow the steps in Example 2 to the end of mixing. However, in order to take advantage of the magnetic crystal anisotropy and stress anisotropy of this magnetic powder, the mixed materials are oriented and pressed into flakes in a press and a magnetic field before kneading and rolling, with a pressure of 1 ton / cm 2 . The mixture pressed into a sheet was completely followed the steps in Example 2, kneaded and rolled, and finally the thickness of the magnet was pressed to 2.0 mm. The magnetically anisotropic rolled magnet of the present invention was obtained, and its properties are shown in Table 5.

[0054] Table 5.Nd 7.1 Fe 80.8 V 11.04 Si 0.46 N 8.8 Properties of Calendered Rubber Flexible Magnets

[0055] Br(kG)

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Abstract

Using specific technique of rapid hardening slice produces alloy based on neodymium (or praseodymium) iron. Then, through reaction of gas-solid phase, crumbling procedure produces RxFe100-x-y-zMyIz magnetic powder. The magnetic powder is single crystal grain in sheet form with average grain size as 1-3 micro. The magnetic powder produced by the disclosed technique possesses anisotropy of magnetocrystalline under action of external magnetic field as well as rolling anisotropy and stress anisotropy. Based on three kinds of anisotropy, the invention discloses method for preparing high performance flexible rubber magnet with rolling anisotropy. The prepared flexible magnet possesses excellent magnetism, flat surface, good cohesiveness, and feasible mechanical properties including tensile strength, extensibility, and rigidity as well as characteristics of temperature resisting, moisture resistance, oil proof and anticorrosion.

Description

technical field [0001] The invention relates to rare earth magnetic materials, in particular to the manufacturing technology of calendered anisotropic magnetic powder and anisotropic calendered flexible rubber magnet. Background technique [0002] There are two types of rare earth magnets: sintered magnets and bonded magnets. In recent years, bonded magnets have developed rapidly, and bonded magnets are divided into different categories such as molded magnets, injection magnets, extruded magnets and calendered magnets due to different molding techniques and corresponding different properties. Flexible bonded magnets manufactured by calendering technology are easy to process, low in cost, and have huge application demands. Among the existing permanent magnetic materials, only ferrite magnetic powder has calendering anisotropy, that is, the magnetic moment of magnetic powder can be aligned and oriented during the molding process of mixing and calendering, so ferrite has been ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/053H01F1/08H01F41/02
Inventor 杨应昌
Owner NINGXIA MAGVALLEY NOVEL MATERIALS TECH CO LTD
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