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A method and additive for reducing oxygen content of sintered NdFeB material

An additive, NdFeB technology, applied in the direction of magnetic materials, inductor/transformer/magnet manufacturing, magnetic objects, etc., can solve problems such as cracking, magnet performance degradation, and easy agglomeration

Active Publication Date: 2021-09-14
ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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  • Summary
  • Abstract
  • Description
  • 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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  • A method and additive for reducing oxygen content of sintered NdFeB material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Sintering NdFeB method of this embodiment comprises the following process steps:

[0034] (1) weight ratio Ⅰ and Ⅱ formulation additives:

[0035] Ⅰ type additive formulation: BTA (1%), 200 # solvent oil (60%), isopropanol (25%), cyclohexanone (14%);

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

[0037] (2) the additives Ⅰ, automatic pulse added atomizer feeder hydrogen pulverization furnace at the outlet of the control additive amount of the powder of NdFeB weight of 1.0 ‰, at room temperature, was added a spray manner neodymium iron boron powder, can be mixed in the pipeline, without additional mixing tank for mixing process;

[0038] (3) The mixed powder fed to the jet mill feed tank, a jet mill to adjust the particle size to control the speed of 2.8 ~ 3.0μm, adding automatic pulse feeder atomizer discharge opening at the lower jet mill apparatus ⅱ ...

Embodiment 2

[0043] Sintering NdFeB method of this embodiment comprises the following process steps:

[0044] (1) weight ratio Ⅰ and Ⅱ formulation additives:

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

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

[0047] (2) the additives Ⅰ, automatic pulse added atomizer feeder hydrogen pulverization furnace at the outlet of the control additive amount of the powder of NdFeB weight 1.5 ‰; at room temperature, was added a spray manner neodymium iron boron powder, can be mixed in the pipeline, without additional mixing tank for mixing process;

[0048] (3) The mixed powder delivered to the jet mill feed tank, a jet mill to adjust the particle size to control the speed of 2.8 ~ 3.0μm; add automatic pulse feeder atomizer discharge opening at the lower jet mill apparatus ⅱ ...

Embodiment 3

[0053] Sintering NdFeB method of this embodiment comprises the following process steps:

[0054] (1) weight ratio Ⅰ and Ⅱ formulation additives:

[0055] Ⅰ type additive formulation: BTA (5%), 200 # solvent oil (20%), isopropanol (45%), cyclohexanone (20%);

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

[0057] (2) the additives Ⅰ, automatic pulse added atomizer feeder hydrogen pulverization furnace at the outlet of the control additive amount of the powder of NdFeB weight 1.0 ‰; at room temperature, was added a spray manner neodymium iron boron powder, can be mixed in the pipeline, without additional mixing tank for mixing process;

[0058] (3) The mixed powder delivered to the jet mill feed tank, a jet mill to adjust the particle size to control the speed of 2.8 ~ 3.0μm; add automatic pulse feeder atomizer discharge opening at the lower jet mill apparat...

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Abstract

The invention relates to the technical field of permanent magnet materials, and discloses a method and additives for reducing the oxygen content of sintered NdFeB materials. The method of the present invention adopts the pre-grinding and post-grinding two-step method to carry out anti-oxidation protection to the magnetic powder, and the pre-milling and post-grinding additives adopt different formulations (Type I and Type II), wherein the Type I additives include BTA, 200# solvent oil , isopropanol and cyclohexanone; Type II additives include stearate and 120# solvent oil, oleic acid amide, terpineol, petroleum ether and stadis (R) 450. In the present invention, the additive is added to the NdFeB powder in the form of continuous spraying, and the particle surface of the NdFeB powder is evenly coated, which improves the anti-oxidation effect of the NdFeB powder. The chain segment of the type I additive is slightly longer, It is convenient to cover the new section produced by jet milling; the chain segment of type II additive is slightly short and contains lubricant and polar group components, which can weaken the static magnetic effect between powder particles and reduce the agglomeration between powder particles, which is beneficial to improve degree of orientation.

Description

Technical field [0001] The present invention relates to the technical field of permanent magnet material, particularly to a method and an additive for reducing the oxygen content of the sintered NdFeB material. Background technique [0002] NdFeB (NdFeB) permanent magnet materials are mainly iron, boron and some of the added metal such as Co, Cu, Al, Ga prepared from rare earth metal elements such as praseodymium, neodymium formed by a powder metallurgy process. NdFeB invention since, because of its high energy product, high coercivity, and light weight characteristics of the magnetic device to efficient, compact, lightweight direction. However, in the manufacturing process of sintered NdFeB material remaining in the following problems: First, the NdFeB powder needs nitrogen, stored or exposed to the air, the transfer is easily oxidized, damp, seriously affect the magnetic properties; Second when pressing the alignment between the NdFeB powder particles easily agglomerate due to ...

Claims

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Application Information

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Patent Type & Authority Patents(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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