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Production method for sintered neodymium-iron-boron permanent magnets

A production method and technology of permanent magnets, applied in the direction of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve problems that cannot be fundamentally solved, have a single easy magnetization direction, and cannot be overcome

Active Publication Date: 2015-07-01
BEIJING ZHONG KE SAN HUAN HI TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, none of the existing NdFeB permanent magnet manufacturing technologies can overcome the difficulty of the presence of large rare earth-rich phases in the magnet.
[0010] For example, CN1468319A proposes a method of mixing Nd-Fe-B alloy powders with different components to improve the morphology or distribution of the bulk rare earth-rich phase. The average particle size is the same as the average grain size, all powder particles are single crystals, and have a single easy magnetization direction, and the particles are very easy to annex each other and grow up during the sintering process; Fundamentally solve the difficulty of the presence of bulky rare earth-rich phases in magnets

Method used

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  • Production method for sintered neodymium-iron-boron permanent magnets
  • Production method for sintered neodymium-iron-boron permanent magnets
  • Production method for sintered neodymium-iron-boron permanent magnets

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] First, the ingredients are prepared according to the alloy A with the total rare earth content TRE=32.0wt.% in Table 1, and then the master alloy is made into a master alloy by the usual smelting method, and then the master alloy is hydrogenated and pulverized by a jet mill to form a master alloy powder. The grain size is 3.0~5.0μm; according to the alloy B with the total rare earth content TRE=26.8wt.% in Table 1, the ingredients are made, and the auxiliary alloy flakes are made by the quenching and smelting method, and the auxiliary alloy flakes are directly coarsely crushed and then jet milled Auxiliary alloy powder is obtained by crushing, and the grain size of the auxiliary alloy powder is 0.1-0.01 μm. The average particle size of the powders of alloy A and alloy B is 3.6 μm.

[0043] The powder of alloy A with a weight fraction of 98wt.% and the powder of alloy B with 2wt.% are fully mixed in a powder mixer, and then oriented under a magnetic field of 1.95T, 0.8t / ...

Embodiment 2

[0052] The preparation process, grain size and average particle size of the master alloy powder (alloy A powder) and auxiliary alloy powder (alloy B powder) used in Example 2 are exactly the same as those in Example 1. Mix 98wt.% Alloy A powder and 2wt.% Alloy B auxiliary powder in a powder mixer, orient under a magnetic field of 1.95T, 0.8t / cm 2 Compressed under pressure, sintered at 1070°C to form a magnet with a size of 51*51*25mm, and then tempered at 900°C and 480°C. The magnetic performance data of the fabricated magnets were measured, and the results are shown in Table 2.

Embodiment 3

[0058] The composition of 98wt.% is the same as the alloy A in Table 1, and the coarse powder obtained after the master alloy is made into a master alloy by a conventional smelting method is crushed in hydrogenation, and the composition of 2wt.% is the same as that of the alloy in Table 1. The coarse powder that is the same as in B, made into auxiliary alloy flakes by the quenching and smelting method without hydrogenation treatment, is fully mixed in the powder mixer, and then the mixture is pulverized by a jet mill, and the average particle size is 3.4 μm. of powder. Then oriented under 1.95T magnetic field, 0.8t / cm 2 Press molding, sintering at 1050°C to form a magnet with a size of 51*51*25mm, and then after secondary tempering at 900°C and 480°C, the magnetic performance data is measured with an automatic magnetic measuring device, as shown in Table 2.

[0059] It can be seen that compared with Comparative Example 1, the coercive force Hcj, maximum energy product (BH)m a...

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Abstract

Disclosed is a production method for sintered neodymium-iron-boron permanent magnets. The method is a dual-alloy method using master alloy and auxiliary alloy and is characterized in that the grain size of the auxiliary alloy ranges from 0.01 micrometers to 0.1 micrometers. The method includes that quenching auxiliary neodymium-iron-boron powder with total rare earth content obviously lower than master alloy powder and the grain size far less than particle size is added to sintered master neodymium-iron-boron alloy powder with the total rare earth content ranging from 28wt.% to 35wt.% and the average particle size and grain size ranging from 3.0 micrometers to 5.0 micrometers. Grains of Neodymium-iron-boron compact is prevented from growing rapidly, generation of bulk-shaped rich rare earth phase on the boundary of neodymium-iron-boron main phase is reduced, and the neodymium-iron-boron permanent magnets low in production cost and high in performance are obtained.

Description

technical field [0001] The invention relates to a method for manufacturing a sintered NdFeB permanent magnet, in particular to a method for manufacturing a low-cost, high-performance permanent magnet by inhibiting the rapid growth of crystal grains in the sintering process of an NdFeB compact. Background technique [0002] As is well known to those skilled in the art, there are mainly two phases in NdFeB alloys: one is the main phase, and the chemical formula is RE 2 Fe 14 B, is the key phase that produces high permanent magnetic properties, and its volume fraction accounts for more than 95%; the other phase is a rare earth-rich phase, distributed in RE 2 Fe 14 The boundary of the B main phase grains acts to isolate the magnetostatic interaction between the main phase grains so that the magnet has as high an intrinsic coercive force as possible. Therefore, in order to obtain excellent permanent magnetic properties, it is necessary to configure the chemical composition of ...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F1/057B22F1/00B22F9/04
Inventor 何叶青惠英林
Owner BEIJING ZHONG KE SAN HUAN HI TECH
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