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Method for preparing neodymium-iron-boron magnet through grain boundary diffusion

Through inorganic acid solution immersion and low-temperature pressurization followed by high-temperature diffusion technology, a heavy rare earth metal shell structure is formed, which solves the problem of insufficient diffusion depth of NdFeB magnets in the existing technology, significantly improves the coercive force and is suitable for thicker of samples.

Active Publication Date: 2020-09-25
NINGDE XINGYU TECH CO LTD
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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 neodymium-iron-boron magnet through grain boundary diffusion

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Effect test

Embodiment 1

[0028] A method for preparing NdFeB magnets by grain boundary diffusion, comprising 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, (Numerical value represents the diffusion alloy of atomic percentage) is attached to the upper and lower surfaces of the basic NdFeB magnet after step 1 treat...

Embodiment 2

[0034] A method for preparing NdFeB magnets by grain boundary diffusion, comprising the following steps:

[0035] 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;

[0036] 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, (Numerical value represents the diffusion alloy of atomic percentage) is attached to the upper and lower surfaces of the basic NdFeB magnet after step 1 treatment, is ...

Embodiment 3

[0040] A method for preparing NdFeB magnets by grain boundary diffusion, comprising the following steps:

[0041] Step 1: Process the commercial NdFeB magnet into 5mm*10mm*10mm (10mm 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 4% 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 750W, and the temperature is 45°C) for 7min, and then dry at 130°C for 60min;

[0042] Step 2: Diffusion alloy sheets with a thickness of 0.15 mm (prepared by a quick-setting process and composed of Pr 50 Tb 20 Cu 30, (Numerical value represents the diffusion alloy of atomic percentage) is attached to the upper and lower surfaces of the basic NdFeB magnet after step 1 tr...

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Abstract

The invention provides a method for preparing a neodymium-iron-boron magnet through grain boundary diffusion. The method comprises the steps that: a basic neodymium-iron-boron magnet with the thickness ranging from 8 mm to 12 mm is dried after being treated with a dilute inorganic acid solution; diffusion alloy sheets Pr50Tb20Cu30 are attached to the upper surface and the lower surface of the dried basic neodymium-iron-boron magnet, then the basic neodymium-iron-boron magnet with the diffusion alloy sheets is put into a hot-pressing furnace, the hot-pressing furnace is vacuumized, is heated to700-800 DEG C in a vacuum state, a pressure of 20-30MPa is applied initially, the pressure is maintained for 7-10 hours, then the pressure is relieved to normal pressure, vacuumizing is preformed again, continuous heating is performed to 850-950 DEG C, and the temperature is kept for 1-2 hours; and annealing treatment is carried out on a diffused sample in the vacuum furnace at different temperatures in sequence. According to the method, the neodymium-iron-boron magnet with satisfactory magnet coercive force, residual magnetism and sample thickness can be produced.

Description

[0001] This case is a divisional application based on the invention patent with the application date of 2017-11-29, the application number of 201711223146.2, and the title of "a method for preparing a neodymium-iron-boron magnet". technical field [0002] The invention relates to the technical field of magnet preparation, in particular to a method for preparing an NdFeB magnet by grain boundary diffusion. Background technique [0003] 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. [0004] Add heavy rare earth by alloying method to form high magnetocrystalline anisotropy (NdDy) 2 Fe 14 The B har...

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 NINGDE XINGYU TECH CO LTD