Method for reducing oxygen content of sintered neodymium iron boron material, and additive

An additive, NdFeB technology, applied in magnetic materials, inductor/transformer/magnet manufacturing, permanent magnet manufacturing, etc., can solve the problems of reduced magnet performance, easy to be oxidized, damp, reduce production efficiency, etc. Contact with moisture, improve anti-oxidation, increase fluidity and mobility

Active Publication Date: 2019-11-12
ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are still the following problems in the manufacturing process of sintered NdFeB permanent magnet materials: First, NdFeB powder needs nitrogen protection, and it is easy to be oxidized and damp when exposed to the air or stored or transferred, which seriously affects the performance of the magnet; During oriented pressing, the NdFeB powder particles are easy to agglomerate due to the static magnetism, resulting in poor fluidity of the powder, affecting the uniformity of dispersion after entering the mold cavity, and resulting in uneven density of green embryos after pressing, eventually causing A series of problems such as deformation and cracking of the magnet after sintering
However, this method weighs and mixes the powder and additives before and after grinding, which reduces the production efficiency, and at the same time, it is easy to mix in oxygen when mixing materials and adding additives, which will cause the magnetic powder to oxidize and reduce the performance of the magnet.

Method used

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  • Method for reducing oxygen content of sintered neodymium iron boron material, and additive

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] The preparation method of sintered NdFeB of this embodiment includes the following process steps:

[0034] (1) Prepare type Ⅰ and type Ⅱ additives according to weight ratio:

[0035] Preparation of Type I additives: BTA (1%), 200# solvent oil (60%), isopropanol (25%), cyclohexanone (14%);

[0036] Preparation of type II additives: zinc stearate (5%), 120# solvent oil (60%), oleic acid amide (10%), terpineol (10%), petroleum ether (10%), stadis(R) 450(5%);

[0037] (2) Take additive I and add it to the automatic pulse atomizing feeder at the outlet of the hydrogen crushing furnace, and control the additive ratio to be 1.0‰ of the weight of the powder in the neodymium iron boron. Add the neodymium iron by spraying at room temperature. The boron powder can be mixed evenly in the conveying pipeline, without additional mixing tank for mixing treatment;

[0038] (3) Transport the uniformly mixed powder to the feeder tank of the jet mill, adjust the speed of the jet mill to control th...

Embodiment 2

[0043] The preparation method of sintered NdFeB of this embodiment includes the following process steps:

[0044] (1) Prepare type Ⅰ and type Ⅱ additives according to weight ratio:

[0045] Formulation of type I additives: BTA (3%), 200# solvent oil (40%), isopropanol (35%), cyclohexanone (22%);

[0046] Formulation of type II additives: zinc stearate (8%), 120# solvent oil (40%), oleic acid amide (8%), terpineol (20%), petroleum ether (21%), stadis(R) 450(3%);

[0047] (2) Take additive I and add it to the automatic pulse atomizing feeder at the exit of the hydrogen crushing furnace, and control the additive ratio to 1.5‰ of the weight of the powder in the neodymium iron boron; at room temperature, add the neodymium iron by spraying The boron powder can be mixed evenly in the conveying pipeline, without additional mixing tank for mixing treatment;

[0048] (3) Transport the uniformly mixed powder to the feeder tank of the jet mill, adjust the speed of the jet mill to control the part...

Embodiment 3

[0053] The preparation method of sintered NdFeB of this embodiment includes the following process steps:

[0054] (1) Prepare type Ⅰ and type Ⅱ additives according to weight ratio:

[0055] Preparation of Type I additives: BTA (5%), 200# solvent oil (20%), isopropanol (45%), cyclohexanone (20%);

[0056] Preparation of type II additives: aluminum stearate (10%), 120# solvent oil (20%), oleic acid amide (30%), terpineol (30%), petroleum ether (32%), stadis(R) 450(2%);

[0057] (2) Take additive I and add it to the automatic pulse atomizing feeder at the exit of the hydrogen crushing furnace, and control the additive ratio to be 1.0‰ of the weight of the powder in the neodymium iron boron; at room temperature, add neodymium iron by spraying The boron powder can be mixed evenly in the conveying pipeline, without additional mixing tank for mixing treatment;

[0058] (3) Transport the uniformly mixed powder to the feeder tank of the jet mill, adjust the speed of the jet mill to control the...

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Abstract

The invention relates to the technical field of permanent magnet materials, and discloses a method for reducing oxygen content of a sintered neodymium iron boron material, and an additive. According to the method disclosed by the invention, magnetic powder is subjected to anti-oxidation protection by adopting a two-step method before grinding and after grinding, and different formulas (II type andII type) are adopted for the additive before grinding and after grinding, wherein the I-type additive comprises BTA, 200# solvent oil, isopropanol and cyclohexanone; and the II-type additive comprises stearate and 120# solvent oil, oleamide, terpilenol, petroleum ether and stadis (R) 450. The additive is added into the neodymium iron boron powder in a continuous spraying manner, so that the particle surfaces of the neodymium iron boron powder are uniformly coated, and the antioxidant effect of the neodymium iron boron powder is improved; the chain section of the I type additive is slightly longer, and the new section caused by airflow grinding is conveniently coated; the chain segment of the type II additive is slightly short and contains a lubricant and a polar group component, so that the static magnetic effect between the powder particles can be weakened, agglomeration between powder particles is reduced, and the orientation degree is improved.

Description

Technical field [0001] The invention relates to the technical field of permanent magnet materials, in particular to a method and additives for reducing the oxygen content of sintered NdFeB materials. Background technique [0002] Sintered neodymium iron boron (NdFeB) permanent magnet materials are mainly made of rare earth metals, neodymium praseodymium, iron, boron and some additional metals such as Co, Cu, Al, Ga and other elements through powder metallurgy. Since the invention of neodymium iron boron permanent magnet materials, due to its high magnetic energy product, high coercivity, light weight and other characteristics, magnetic devices have developed in the direction of high efficiency, miniaturization and light weight. However, there are still the following problems in the manufacturing process of sintered NdFeB permanent magnet materials: First, NdFeB powder needs nitrogen protection, and it is easy to be oxidized and damp when exposed to air, stored or transferred, whi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0577H01F41/026H01F41/0266
Inventor 洪群峰郝忠彬叶志晓
Owner ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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