Bonded ferrite magnetic powder for injection molding as well as preparation method and application of bonded ferrite magnetic powder

A ferrite magnet and injection molding technology, which is applied in the manufacture of inductors/transformers/magnets, magnetic materials, magnetic objects, etc., can solve the problems of increasing the volume ratio of magnetic powder, reducing the magnetic performance of magnets, and increasing volume, and achieve magnetic Can improve, increase stability and reliability, and broaden the effect of application fields

Pending Publication Date: 2022-01-04
BGRIMM TECH CO LTD
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  • Description
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Problems solved by technology

[0006] (3) Chinese patent application CN201080016639.9 discloses a ferrite powder for bonded magnets and its manufacturing method, as well as a bonded magnet using it. The average particle size range of powder and fine powder, the fine powder accounts for 15-40% of the weight of the mixed powder, the bonded magnet uses nylon 6 as the binder, and the magnet shape is rigid
[0008] (1) The mixing process of coarse powder and fine powder in the prior art is all used to prepare bonded magnets whose magnet form is rigid, and the binders used in the bonded magnets are all nylon-based binders. It cannot be bent and deformed to cooperate with complex parts, and the application field is greatly limited
[0009] (2) Coarse powder and fine powder mixing process in the prior art all are to make coarse powder and fine powder respectively earlier, then adopt dry mixing method or wet mixing method to mix coarse powder and fine powder, after the method mixes fine powder and coarse powder The dense combination between the coarse and fine mixed magnetic powder will increase the volume of the coarse and fine mixed magnetic powder. When molding with high powder content, due to the resistance of the binder in the molten state, the fine powder in the thick and fine mixed magnetic powder will be filled to the maximum in the binder. The difficulty of the gap between the coarse powder increases, resulting in an increase in the volume ratio of the magnetic powder in the magnet, which is not conducive to improving the fluidity and magnetic properties
[0010] (3) The magnetic powder formula used in the coarse powder and fine powder mixing process in the prior art is unreasonable, which makes the particle size uniformity of coarse ferrite magnetic powder and fine ferrite magnetic powder not good, and produces a lot of excessive magnetic powder Particles and too small magnetic powder particles, the size of the magnetic powder particles is relatively dispersed, which is not conducive to the filling of fine particle magnetic powder, and reduces the magnetic properties of the magnet

Method used

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  • Bonded ferrite magnetic powder for injection molding as well as preparation method and application of bonded ferrite magnetic powder
  • Bonded ferrite magnetic powder for injection molding as well as preparation method and application of bonded ferrite magnetic powder
  • Bonded ferrite magnetic powder for injection molding as well as preparation method and application of bonded ferrite magnetic powder

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preparation example Construction

[0065] The present invention provides a method for preparing bonded ferrite magnetic powder for injection molding, which is used to prepare the above-mentioned bonded ferrite magnetic powder for injection molding provided by the present invention, which specifically includes the following steps: The fine-grained ferrite magnetic powder and the coarse-grained ferrite magnetic powder with an average particle size of 3.0-6.0 microns are added to a ball mill for ball milling according to the weight ratio of the fine-grained ferrite magnetic powder accounting for 10-35 wt%, so as to obtain The coarse and fine mixed magnetic powder is the bonded ferrite magnetic powder for injection molding provided by the present invention.

[0066] In a preferred embodiment of the present invention, the ball milling includes: fine-grained ferrite magnetic powder with an average particle size of 0.5-1.2 microns, coarse-grained ferrite magnetic powder with an average particle size of 3.0-6.0 microns,...

Embodiment 1

[0085] An injection molded flexible bonded magnet, the preparation method of which may comprise the following steps:

[0086] Step A1, preparation of fine-grained ferrite magnetic powder: Weigh iron oxide and strontium carbonate according to the molar ratio of iron oxide:strontium carbonate=5.78:1; Iron and bismuth oxide with a total weight of 0.2wt% of the strontium carbonate and strontium chloride accounting for 2.98wt% of the total weight of the iron oxide and strontium carbonate are mixed together and granulated with water to make 5-10 mm in diameter The pellets were dried in an oven at 130°C, and the dried pellets were placed in an electric furnace and sintered at 1250°C for 2 hours, then crushed with a jaw crusher, and then ball milled with a JM-2L wet ball mill for 6 hours. The fine-grained ferrite magnetic powder with an average particle diameter of 0.5 microns was obtained.

[0087]Step A2, preparation of coarse-grained ferrite magnetic powder: Weigh iron oxide and s...

Embodiment 2

[0102] An injection molded flexible bonded magnet, the preparation method of which may comprise the following steps:

[0103] Step B1, preparation of fine-grained ferrite magnetic powder: Weigh iron oxide and strontium carbonate according to the molar ratio of iron oxide:strontium carbonate=5.78:1; Iron and bismuth oxide with a total weight of 0.2wt% of the strontium carbonate and strontium chloride accounting for 2.98wt% of the total weight of the iron oxide and strontium carbonate are mixed together and granulated with water to make 5-10 mm in diameter The pellets were dried in an oven at 130°C, and the dried pellets were placed in an electric furnace and sintered at 1250°C for 2 hours, then crushed with a jaw crusher, and then ball milled with a JM-2L wet ball mill for 4 hours. Fine-grained ferrite magnetic powder with an average particle diameter of 0.8 μm was obtained.

[0104] Step B2, preparation of coarse-grained ferrite magnetic powder: Weigh iron oxide and strontium...

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Abstract

The invention discloses bonded ferrite magnetic powder for injection molding as well as a preparation method and application of bonded ferrite magnetic powder. The bonded ferrite magnetic powder for injection molding is prepared by adding fine ferrite magnetic powder with the average particle size of 0.5-1.2 microns and coarse ferrite magnetic powder with the average particle size of 3.0-6.0 microns into a ball mill according to the weight ratio that the fine ferrite magnetic powder accounts for 10-35wt%, and carrying out ball milling, thereby obtaining coarse and fine mixed magnetic powder. The bonded ferrite magnetic powder for injection molding can be mixed with a rubber binder, a plasticizer and a stabilizer to prepare an injection-molded flexible bonded magnet. The flowability of the magnetic powder and the magnetic performance of the magnet can be greatly improved and exceed the level of existing like products, and the upper limit of the use temperature of the injection molding flexible bonded magnet can be improved to 125 DEG C from 80 DEG C, so that the application field of the injection molding flexible bonded magnet is widened, and the stability and the reliability of the injection molding flexible bonded magnet are improved.

Description

technical field [0001] The invention relates to the field of injection molding flexible bonded magnets, in particular to a bonded ferrite magnetic powder for injection molding and its preparation method and application. Background technique [0002] Injection molding magnets require high fluidity of the magnetic powder to fill the mold and inject and mold them into magnetic devices with complex shapes. Generally, the volume ratio of the binder in the magnet is increased by reducing the powder content and reducing the volume ratio of the magnetic powder in the magnet. , so as to improve the fluidity of magnetic powder, but this will reduce the magnetic properties of injection molded magnets. Simply increasing the powder content will improve the magnetic properties to a certain extent, but this will reduce the fluidity, deteriorate the mechanical properties of the magnet, and even cause problems that cannot be formed. [0003] In order to solve the above problems in terms of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/03H01F41/02
CPCH01F1/0315H01F41/02
Inventor 王峰熊君胡国辉周超邢献虎王继全唐大为刘辉贾立颖孙威
Owner BGRIMM TECH CO LTD
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