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Method for preparing high coercivity Nd-Fe-B magnet

A high coercivity, NdFeB technology, used in inductor/transformer/magnet manufacturing, electrical components, circuits, etc., can solve the effect of added amount of magnet performance, insignificant increase in coercivity, and grain growth inhibition effect limited and other problems, to achieve the effect of uniform distribution, small grain size and easy operation

Active Publication Date: 2018-12-07
NINGBO ZHAOBAO MAGNET
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this process is limited to the production of thinner magnetic parts (thickness generally does not exceed 5mm), and the coercive force is not significantly improved when preparing large magnets
[0004] At present, the method of refining magnet grains is mainly to add trace elements such as W, Mo, V, Ti, Ta, Zr, Nb, Co, Cr, Ga to the magnet composition to inhibit the growth of magnet grains, but Such elements will have uneven distribution such as segregation in the magnet, and the inhibitory effect on grain growth is limited. If the addition amount is too high, it will have a serious impact on the performance of the magnet.

Method used

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  • Method for preparing high coercivity Nd-Fe-B magnet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] 1) NdFeB alloy quick-setting tablets are prepared by using the quick-setting process, and then coarsely crushed into coarse particles with a particle size of 50-200 μm, and its composition is Nd 31.5 Fe 66.31 B 0.95 co 1.2 Cu 0.04 .

[0018] 2) Mix the above-mentioned NdFeB coarse powder with 1mol / L silane aqueous solution, and perform ball milling for 2 hours; add 1L silane aqueous solution to every 100g NdFeB coarse powder, and the silane aqueous solution is an aqueous solution in which monosilane is dissolved in water.

[0019] 3) to step 2) in the ball milling product, add again containing Dy or Tb compound, continue ball milling 2 hours; Containing Dy or Tb compound is the nitrate of dysprosium, wherein the addition of the nitrate of dysprosium (in moles) is Add 0.05 mole of compound per mole of NdFeB coarse powder.

[0020] 4) The ball mill product is washed and dried, and the dried product is calcined for 1 hour; the calcining temperature is 300°C. Ar / H was...

Embodiment 2

[0027] 1) NdFeB alloy quick-setting tablets are prepared by using the quick-setting process, and then coarsely crushed into coarse particles with a particle size of 50-200 μm, and its composition is Nd 30.5 Fe 67.31 B 0.95 co 1.2 Cu 0.04 .

[0028] 2) Mix the above-mentioned NdFeB coarse powder with 1mol / L silane aqueous solution, and perform ball milling for 2.5 hours; add 1L silane aqueous solution to every 100g NdFeB coarse powder, and the silane aqueous solution is an aqueous solution in which disilane is dissolved in water.

[0029] 3) To the ball milling product in step 2), add the compound containing Dy or Tb again, and continue ball milling for 2.5 hours; the compound containing Dy or Tb is the acetate of dysprosium, wherein the addition of acetate of dysprosium (in moles) ) Add 0.05 mole of compound for every mole of NdFeB coarse powder.

[0030] 4) Washing and drying the ball milled product, and calcining the dried product for 1.5 hours; the calcining temperatur...

Embodiment 3

[0036] 1) NdFeB alloy quick-setting tablets are prepared by using the quick-setting process, and then coarsely crushed into coarse particles with a particle size of 50-200 μm, and its composition is Nd 30.5 Fe 67.26 B 0.1 co 1.2 Cu 0.04 .

[0037] 2) Mix the above-mentioned NdFeB coarse powder with 1mol / L silane aqueous solution, and perform ball milling for 3 hours; add 1L silane aqueous solution to every 100g NdFeB coarse powder, and the silane aqueous solution is an aqueous solution in which silane is dissolved in water.

[0038]3) Add Dy or Tb compound to the ball mill product in step 2) and continue ball milling for 3 hours; Dy or Tb compound is terbium nitrate, wherein the addition of terbium nitrate (in moles) is Add 0.05 mole of compound per mole of NdFeB coarse powder.

[0039] 4) Washing and drying the ball milled product, and calcining the dried product for 1.5 hours; the calcining temperature is 350°C. Ar / H was introduced during the calcination process 2 mix...

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Abstract

The invention discloses a method for preparing a high coercivity Nd-Fe-B magnet, comprising the following steps: 1) preparing Nd-Fe-B coarse powder; 2) mixing the Nd-Fe-B coarse powder with 1 mol / L silane aqueous solution and ball mil for 2 to 4 hours; 3) adding a compound containing Dy or Tb into the ball milling product in the step 2), and continuing ball milling for 2 to 4 hours; 4) washing anddrying the ball mil product, and calcining the dried product for 1 to 2 hours; 5) grinding the calcined product in the step 4) into fine powder, then carrying out magnetic field orientation molding,isostatic pressing, vacuum sintering and tempering heat treatment to obtain the Nd-Fe-B permanent magnetic material. Compared with the traditional process for preparing the neodymium-iron-boron magnet, the method omits the jet milling link and saves the energy consumption. The process of reattaching heavy rare earth elements by silane branching is simple and easy to operate. The Nd-Fe-B magnets have fine grains, uniform distribution of heavy rare earth elements at grain boundaries, and high coercivity.

Description

technical field [0001] The invention relates to the technical field of preparation of rare earth permanent magnet materials, more specifically, it relates to a method for preparing high coercive force NdFeB magnets. Background technique [0002] NdFeB permanent magnet materials are the most concerned rare earth application industry in my country's rare earth industry. With the development of science and technology and technological progress, the demand for high-performance NdFeB permanent magnet materials is becoming more and more extensive. As we all know, in order to improve the coercive force and high temperature usability of NdFeB, the usual method is to add a small amount of heavy rare earth elements (such as Dy, Tb, etc.) or optimize the process to refine the magnet grains. [0003] The currently used methods of adding a small amount of heavy rare earth elements mainly include double alloy process and grain boundary diffusion heavy rare earth element process. The doub...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02
CPCH01F41/0253H01F41/0293
Inventor 林建强贺琦军
Owner NINGBO ZHAOBAO MAGNET