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Method for preparing Nd-Fe-B magnet

A NdFeB magnet technology, applied in the direction of magnetic objects, inductors/transformers/magnet manufacturing, magnetic materials, etc., can solve the problems of limited diffusion depth of grain boundary penetration technology and inability to diffuse heavy rare earth elements, etc., to achieve satisfactory sample thickness, Satisfied residual magnetism and improved coercive force

Active Publication Date: 2018-05-08
宁德市星宇科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for sintered NdFeB magnets, the current grain boundary infiltration technology has a limited diffusion depth, and heavy rare earth elements cannot diffuse into larger magnets. The size of the sample is strict, and generally only thin sheet magnets (within 5mm )

Method used

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  • Method for preparing Nd-Fe-B magnet

Examples

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preparation example Construction

[0015] The invention provides a method for preparing an NdFeB magnet, comprising the following steps:

[0016] Step 1: Process the commercial NdFeB magnet into a thickness of 8-12mm along the direction of the orientation force to obtain the basic NdFeB magnet, and then soak the basic NdFeB magnet in a hydrochloric acid solution with a volume concentration of 3-5% or a volume concentration of In 3-5% nitric acid solution for 5-20 minutes, then dry at 120-140°C for 20-120 minutes;

[0017] Step 2: Attach the diffusion alloy sheet to the upper and lower surfaces of the basic NdFeB magnet treated in step 1, then place it in the hot-press furnace, and vacuum the hot-press furnace until the vacuum degree reaches 1×10 -2 Below Pa, heat up the hot-press furnace. When the temperature reaches 700-800°C, start to apply a pressure of 20-30 MPa, and keep the pressure for 7-10 hours, then release the pressure to normal pressure, and then re-evacuate the hot-press furnace. degrees up to 1×1...

Embodiment 1

[0028] A kind of preparation method of neodymium iron boron magnet, comprises the following steps:

[0029]Step 1: Process the commercial NdFeB magnet into 5mm*10mm*8mm (8mm is the thickness) to obtain the basic NdFeB magnet (the composition of the basic NdFeB magnet is: Pr: 5.9%; Nd: 23.4%; Dy: 1%; B: 0.98%; Al: 0.1%; Cu: 0.1%; Zr: 0.1% and Fe: 68.42%;), and then soak the basic NdFeB magnet in a volume concentration of 3% In the hydrochloric acid solution, ultrasonically treat the NdFeB sheet soaked in the hydrochloric acid solution under vacuum conditions (the power of the ultrasonic treatment is 700W, and the temperature is 50°C) for 10min, and then dry at 120°C for 120min;

[0030] Step 2: Diffusion alloy sheets with a thickness of 0.1mm (prepared by a quick-setting process and composed of Pr 50 Tb 20 Cu 30 , (the numerical value represents the atomic percentage) of the diffusion alloy) is attached to the upper and lower surfaces of the basic NdFeB magnet processed in s...

Embodiment 2

[0034] Step 1: Process the commercial NdFeB magnet into 5mm*10mm*12mm (12mm is the thickness) to obtain the basic NdFeB magnet (the composition of the basic NdFeB magnet is: Pr: 5.9%; Nd: 23.4%; Dy: 1%; B: 0.98%; Al: 0.1%; Cu: 0.1%; Zr: 0.1% and Fe: 68.42%;), and then soak the basic NdFeB magnet in a volume concentration of 5% In the nitric acid solution, ultrasonically treat the NdFeB sheet soaked in the nitric acid solution under vacuum conditions (the power of the ultrasonic treatment is 800W, and the temperature is 40°C) for 5min, and then dry at 140°C for 20min;

[0035] Step 2: Diffusion alloy sheets with a thickness of 0.25 mm (prepared by a quick-setting process and composed of Pr 50 Tb 20 Cu 30 , (the numerical value represents the atomic percentage) of the diffusion alloy) is attached to the upper and lower surfaces of the basic NdFeB magnet processed in step 1, and then placed in the hot-press furnace, and the hot-press furnace is evacuated until the vacuum degree...

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Abstract

The invention provides a method for preparing a Nd-Fe-B magnet. The method includes: using dilute inorganic acid solution to process a basic Nd-Fe-B magnet having a thickness of 8-12 mm, and performing drying; allowing diffusion alloy sheets to attach on an upper surface and a lower surface of the dried basic Nd-Fe-B magnet, putting the basic Nd-Fe-B magnet in a hot-pressing furnace, vacuumizing the hot-pressing furnace, heating the hot-pressing furnace to the temperature of 700-800 DEG C in a vacuum state, applying the pressure of 20-30 MPa, keeping the pressure for 7-10 hours, performing depressurizing to the normal pressure, performing re-vacuumizing, heating the hot-pressing furnace to the temperature of 850-950 DEG C, and keeping the temperature for 1-2 hours; performing annealing treatment on a diffused sample in the vacuum furnace at different temperatures successively, wherein the diffusion alloy sheets are R1-R2-TM, the R1 is Pr or Nd, the R2 is Dy or Tb, and the TM is randomone of Cu, Al, Zn or Fe. The method can acquire the Nd-Fe-B magnet having satisfactory magnet coercivity, remanence and sample thickness.

Description

technical field [0001] The invention relates to the technical field of magnet preparation, in particular to a preparation method of an NdFeB magnet. Background technique [0002] As an important metal functional material, sintered NdFeB magnets are widely used in many fields such as aerospace and navigation, information electronics, energy, transportation, communication, medical and health care, etc. In many fields, such as electric vehicles, hybrid vehicles and wind power generation, sintered NdFeB magnets are required to have higher coercive force to meet the use requirements at a certain temperature. [0003] Add heavy rare earth by alloying method to form high magnetocrystalline anisotropy (NdDy) 2 Fe 14 The B hard magnetic phase can significantly increase the coercive force of the magnet and reduce the attenuation of magnetic properties caused by high temperature, but at the same time, Dy atoms and Fe atoms will form antiferrocoupling, resulting in a decrease in reman...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02H01F1/057
CPCH01F1/057H01F41/0293
Inventor 吕竹风黄家炽
Owner 宁德市星宇科技有限公司