Method for preparing anisotropy nano-crystalline neodymium-iron-boron magnet

An anisotropic, nanocrystalline technology, used in magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problem of uneven deformation of B grains, poor regularity of grain morphology, and excessively large and uniform grains. problems, such as excellent anisotropy, reduced energy consumption, and small grain size

Active Publication Date: 2013-12-04
SICHUAN UNIV
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Problems solved by technology

The problem with this method is that because the compact is formed under high temperature and high pressure, some grains of the Nd-Fe-B compact may be too large and have poor uniformity, resulting in the NdFeB magnet obtained after thermal deformation. 2 Fe 14 The degree of deformation of the B grain is uneven, the regularity of the grain shape is poor, the orientation consistency is poor, and the energy consumption is increased

Method used

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  • Method for preparing anisotropy nano-crystalline neodymium-iron-boron magnet

Examples

Experimental program
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Effect test

Embodiment 1

[0026] In this example, the rapid quenching Nd 13.5 Fe 73 co 7.5 B 6 Magnetic powder is used as raw material to prepare anisotropic nanocrystalline magnet, and the process steps are as follows:

[0027] (1) Nd 13.5 Fe 73 co 7.5 B 6 Preparation of quick quenching powder

[0028] Using metal Nd (purity 99.5%), DT4 electrical pure iron (purity 99.95%), boron iron (boron content 19.65%), metal Co (purity 99.5%) as raw materials, according to Nd 13.5 Fe 73 co 7.5 B 6 Calculate the batching weight of each raw material from the alloy composition (add 1.5wt% Nd as loss compensation when batching). SF2002-4 vacuum intermediate frequency induction melting furnace is used to melt NdFeB alloy, and the melting furnace is evacuated to 1×10 before heating -2 Pa, fill with argon to 0.05MPa, then adjust the power to 38kW according to the calculated alloy composition for smelting, pour the alloy melt into the ingot mold after smelting, and obtain a thin plate ingot after cooling. G...

Embodiment 2

[0036] In this example, the rapid quenching Nd 13.5 Fe 80.4 Ga 0.5 B 5.6 Magnetic powder is used as raw material to prepare anisotropic nanocrystalline magnet, and the process steps are as follows:

[0037] (1) Nd 13.5 Fe 80.4 Ga 0.5 B 5.6 Preparation of quick quenching powder

[0038] Using metal Nd (purity 99.5%), DT4 electrical pure iron (purity 99.95%), boron iron (boron content 19.65%), metal Ga (purity 99.95%) as raw materials, according to Nd 13.5 Fe 80.4 Ga 0.5 B 5.6 Calculate the batching weight of each raw material from the alloy composition (add 1.5wt% Nd as loss compensation when batching). SF2002-4 vacuum intermediate frequency induction melting furnace is used to melt NdFeB alloy, and the melting furnace is evacuated to 1×10 before heating -2 Pa, fill it with argon to 0.05MPa, then adjust the power to 36kW according to the calculated alloy composition for smelting, pour the alloy melt into the ingot mold after smelting, and obtain a thin plate ingot a...

Embodiment 3

[0046] In this example, the rapid quenching Nd 13.5 Fe 80.5 B 6 Magnetic powder is used as raw material to prepare anisotropic nanocrystalline magnet, and the process steps are as follows:

[0047] (1) Nd 13.5 Fe 80.5 B 6 Quick Quenching Powder Preparation

[0048] Using metal Nd (purity 99.5%), DT4 electrical pure iron (purity 99.95%), boron iron (boron content 19.65%) as raw materials, Nd determined according to the design 13.5 Fe 80.5 B 6 Calculate the batching weight of each raw material from the alloy composition (add 1.5wt% Nd as loss compensation when batching). SF2002-4 vacuum intermediate frequency induction melting furnace is used to melt NdFeB alloy, and the melting furnace is evacuated to 1×10 before heating -2Pa, fill it with argon to 0.05MPa, then increase the power to 35kW for smelting according to the calculated alloy composition, pour the alloy melt into the ingot mold after smelting, and obtain a thin plate ingot after cooling. After the thin plate ...

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Abstract

A method for preparing an anisotropy nano-crystalline neodymium-iron-boron magnet comprises the steps that (1) complete hydrogen disproportionate or partial hydrogen disproportionate Nd-Fe-B magnetic powder is prepared; (2) a pressed blank is prepared, the complete hydrogen disproportionate Nd-Fe-B magnetic powder or the partial hydrogen disproportionate Nd-Fe-B magnetic powder prepared in the step (1) is placed in a mold, under the inert gas shielding, pressing is conducted on the magnetic powder at the indoor temperature, and when the pressure intensity received by the magnetic powder is increased to 100MPa-600MPa from 0MPa, pressing is stopped; (3) hot-pressing deformation and dehydrogenation recombination are conducted, so that the temperature of the pressed blank is increased to 680 DEG C-850 DEG C under the vacuum condition, under the conditions that the temperature is 680 DEG C-850 DEG C and the hydrogen partial pressure PH2 satisfies the inequation that 0Pa<PH2<= 1kPa, constant pressure is exerted on the Nd-Fe-B pressed blank so that hot-pressing deformation and dehydrogenation recombination can be conducted, the pressure intensity value is limited in the range that the pressure intensity borne by the Nd-Fe-B hydrogen disproportionate pressed blank in the process of hot-pressing deformation and dehydrogenation ranges from 30MPa to 1.5MPa, and the temperature preservation and pressure preservation time lasts for 5min-120min. The method for preparing the anisotropy nano-crystalline neodymium-iron-boron magnet can improve the performance of the anisotropy nano-crystalline neodymium-iron-boron magnet and reduce energy consumption.

Description

technical field [0001] The invention belongs to the field of preparation of rare earth permanent magnet materials, in particular to a preparation method of anisotropic nanocrystalline neodymium-iron-boron magnets. Background technique [0002] Anisotropic nanocrystalline Nd-Fe-B magnets have the highest theoretical energy product and thus have attracted much attention. At present, the preparation methods of anisotropic nanocrystalline Nd-Fe-B magnets mainly include hydrogen absorption-disproportionation-dehydrogenation-recombination method (HDDR method for short) and hot pressing-hot deformation method. [0003] The HDDR method prepares anisotropic Nd-Fe-B magnets, mainly by reducing the hydrogen partial pressure during disproportionation or adding alloy elements such as Co, Ga, Zr to obtain anisotropic Nd-Fe-B magnetic powder, and then anisotropic Nd - Fe-B magnetic powder and binder are evenly mixed and molded by pressing or injection molding under the action of an extern...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02H01F1/057H01F1/08B22F3/02
Inventor 刘颖李军郑青余云萍
Owner SICHUAN UNIV
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