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Method for preparing anisotropic bonded magnet by adopting pressure-keeping curing process

An anisotropic, pressure-holding and curing technology, used in the manufacture of inductors/transformers/magnets, permanent magnets, inorganic materials, etc. The effect of improved surface quality and increased density

Inactive Publication Date: 2013-03-20
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0017] The purpose of the present invention is to provide a method for preparing a molded anisotropic bonded magnet, which solves the problems of reduced magnet density and poor orientation due to the softening of the binder during the curing process of the existing bonded magnet, thereby preparing a high-quality bonded magnet. Properties of anisotropic bonded magnets

Method used

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  • Method for preparing anisotropic bonded magnet by adopting pressure-keeping curing process
  • Method for preparing anisotropic bonded magnet by adopting pressure-keeping curing process
  • Method for preparing anisotropic bonded magnet by adopting pressure-keeping curing process

Examples

Experimental program
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Effect test

Embodiment 1

[0047]The magnetic powder is HDDR anisotropic NdFeB magnetic powder, the content of epoxy resin binder is 2.5% (mass fraction), the content of silane coupling agent is 0.5% (mass fraction), the temperature of warm pressing is 120℃, and the pressing pressure is 800MPa , the orientation magnetic field is 1.8T, and the pressure-holding and non-pressure-holding curing magnets are prepared respectively. The pressure-holding curing process is: temperature 120 ℃, time 30min and pressure 400MPa. The maximum magnetic energy product of the magnet before and after the pressure-holding is increased by 11.3%.

Embodiment 2

[0049] The magnetic powder is HDDR anisotropic NdFeB magnetic powder, the content of epoxy resin binder is 2.5% (mass fraction), the content of silane coupling agent is 0.5% (mass fraction), the pressing pressure is 800MPa, and the orientation magnetic field is 1.8T. The pressing time is 30min, and the holding pressure is 400MPa. After pressing and holding at room temperature and 120°C, the maximum energy product of the anisotropic bonded magnet cured at 120°C is increased by 76.9% compared with room temperature.

Embodiment 3

[0051] The magnetic powder is HDDR anisotropic NdFeB magnetic powder, the content of epoxy resin binder is 2.5% (mass fraction), the content of silane coupling agent is 0.5% (mass fraction), the temperature of warm pressing is 120℃, and the pressing pressure is 800MPa , the orientation magnetic field is 1.8T, under the pressure of 120 ℃ and 400MPa, the pressure is cured for 2min and 20min, respectively. Compared with the magnet for 2min, the maximum energy product of the magnet for 20min is increased by 7.0%.

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Abstract

The invention relates to a method for preparing an anisotropic bonded magnet by adopting a pressure-keeping curing process. The method uniformly mixes anisotropic magnetic powder, epoxy resin or other thermosetting adhesive, coupling agent, lubricating agent and the like, so that compound magnetic powder is produced, and orienting compression, compression molding and pressure curing are then carried out. In pressure curing, certain pressure stress is kept as the rough is heated to be cured. Pressure curing can adopts two methods: one method is in-situ pressure-prekeeping curing in a mould, i.e., after compression molding and demagnetization, demoulding is not carried out before pressure is kept until the cross-linking curing of the adhesive takes place to a certain degree (the viscosity of the epoxy resin is greater than 18000Pa multiplied by s); in the other method, after compression molding, demoulding is directly carried out, and pressure stress is then applied in the process of curing, for example, the hot isostatic pressing method or the like is adopted to cure the rough under pressure. The adoption of the pressure curing technique can effectively enhance the magnetic property of the bonded magnet.

Description

technical field [0001] The invention belongs to a preparation method of an anisotropic molded bonded magnet, and in particular relates to a pressure-holding and curing technology of an anisotropic bonded magnet with high orientation, high density and high surface smoothness. Background technique [0002] The basic process for preparing molded anisotropic bonded magnets with thermosetting resins is as follows: [0003] Composite magnetic powder is obtained by mixing magnetic powder with binder and additives → magnetic field orientation → molding / warm pressing → demagnetization → curing → anticorrosion treatment → performance testing, where additives refer to lubricants, coupling agents, etc.; Oxygen resin, phenolic resin and other thermosetting resins. When the epoxy resin adhesive is heated within a certain temperature range, the change curve of its viscosity with the holding time is as follows: Figure 1 Show. In the process of heat preservation, firstly, the epoxy resin ...

Claims

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Application Information

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IPC IPC(8): H01F7/02H01F41/02H01F1/08B22F3/02
Inventor 孙爱芝董娟张倩徐文欢吴深强文江
Owner UNIV OF SCI & TECH BEIJING
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