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Method for manufacturing dry press permanent magnetic ferrite

A technology of permanent magnet ferrite and manufacturing method, which is applied in the field of magnetic materials, can solve the problems of limitation of promotion of permanent magnet ferrite, easy cracking of blanks, and low orientation degree of dry pressing magnetic field, and achieves optimization and improvement of particle size and morphology of magnetic powder. Magnetic properties, the effect of improving yield

Active Publication Date: 2016-03-09
武穴东磁磁材有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Compared with wet forming, the preparation of permanent magnet ferrite by dry pressing method also has obvious disadvantages, because there is no medium between the particles, which leads to low orientation degree of dry pressing magnetic field forming and the blank is easy to crack after high temperature sintering. Due to the above reasons, dry The promotion of permanent magnet ferrite prepared by pressing method is subject to certain restrictions

Method used

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  • Method for manufacturing dry press permanent magnetic ferrite
  • Method for manufacturing dry press permanent magnetic ferrite
  • Method for manufacturing dry press permanent magnetic ferrite

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Select the Y38 calcined material on the market, add some required additives according to the mass ratio, and carry out ball milling. The time is 15 hours and the rotation speed is 30r / min. Store the slurry obtained in the above steps at 110° C. until it is dried, and the average size of the particles is about 1.2 μm. After drying the magnetic powder, add 0.4% calcium stearate and 1.2% alcoholic camphor solution (camphor: alcohol = 1:1), and disperse it with a high-speed pulverizer after mixing evenly. The magnetic powder was put into a mold and molded in a magnetic field of 8000Oe with a molding pressure of 4MPa to obtain a molded body with a diameter of 5cm and a height of 1.6cm. The green body was kept at 350°C for 3 hours to remove calcium stearate, and then kept at 1150°C for 3 hours to obtain a ferrite sintered magnet. After grinding and cleaning, the magnet was kept at 23°C for 24 hours, and then the magnetic properties were measured to obtain Br=4061Gs, Hcb=3221...

Embodiment 2

[0030] Select the Y38 pre-fired material on the market, add some required additives according to the mass ratio, and carry out ball milling for 12 hours at a speed of 50r / min. Store the slurry obtained in the above steps at 110° C. until it is dried, and the average size of the particles is about 1.2 μm. After drying the magnetic powder, add 0.5% calcium stearate, 1.0% alcoholic camphor solution, and 0.2% talcum powder, and disperse it with a high-speed pulverizer after mixing evenly. The magnetic powder was put into a mold and molded in a magnetic field of 8000Oe with a molding pressure of 5MPa to obtain a molded body with a diameter of 5cm and a height of 1.5cm. The green body was kept at 400°C for 1 hour to remove calcium stearate, and then kept at 1350°C for 0.1 hour to obtain a ferrite sintered magnet. After grinding and cleaning, the magnet was kept at 23°C for 24 hours, and then the magnetic properties were measured to obtain Br=4103Gs, Hcb=3245Oe, Hcj=3612Oe, (BH)max=...

Embodiment 2 and comparative example 2

[0033] The magnetic property of table 2 embodiment 2 and comparative example 2 magnet

[0034]

[0035] Table 2 shows the magnetic properties of the magnets obtained in Example 2 and Comparative Example 2. It can be seen from Table 2 that adding 0.2% talc powder helps to improve the remanence and the molding pass rate. As a dispersant, talc powder can reduce the friction between dry powders, play a buffering effect, help magnetic field orientation and improve molding rate.

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Abstract

The invention discloses a method for manufacturing dry press permanent magnetic ferrite. The method comprises the following specific operating steps: selecting a pre-sintering material, adding multiple needed additives according to a mass ratio, and performing ball milling; storing the slurry subjected to ball milling until the slurry is dried; drying the magnetic powder, adding 0-0.6 percent of calcium stearate, 0.8-1.2 percent of an alcohol camphor solution and 0-0.4 percent of talcum powder, and dispersing the material by using a high-speed dispersion machine after the materials are uniformly mixed and stirred; tempering the magnetic powder at the temperature of 60-90 DEG C; molding in a magnetic field of 8000Oe or more, thereby obtaining a formed body with the height of 1.2-2cm; maintaining the temperature of the green body at the temperature of 350-400 DEG C for 1-3 hours, and maintaining the temperature at the temperature of 1150-1350 DEG C for 0.1-3 hours; and grinding, cleaning and detecting. The method disclosed by the invention has the beneficial effects that on one hand, technology improvement is performed, and a low-temperature tempering process is increased, so that the particle size and shape of the magnetic powder can be optimized, the degree of orientation is improved, and the magnetic performance is further improved; on the other hand, due to improvement of additives in the granulation process, compression molding is promoted, and the yield is further improved.

Description

technical field [0001] The invention relates to the technical field related to magnetic materials, in particular to a method for manufacturing dry-pressed permanent ferrite. Background technique [0002] M-type permanent ferrite is a ferrimagnetic oxide with good magnetic properties and outstanding cost performance. It is widely used in home appliance motors, sensors, office equipment, automotive motors, medical equipment and other fields. The molecular formula of M-type permanent magnet ferrite can be expressed as AFe 12 o 19 , In industrial production, there are wet and dry methods for magnetic powder orientation molding. Compared with wet magnetic field forming, dry pressing magnetic field forming has the advantages of high efficiency, small shrinkage, and easy control of product size; high-performance dry pressing magnetic field forming permanent magnet sintered ferrite is mainly used to make various Magnetic devices such as relatively small size, thin, complex shape,...

Claims

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Application Information

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IPC IPC(8): C04B35/26C04B35/622C04B35/632
Inventor 吴云飞杨武国李军华郭超阳
Owner 武穴东磁磁材有限公司
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