Method for preparing neodymium iron boron powder by means of hydrothermal method

A technology of NdFeB and hydrothermal method, which is applied in the field of NdFeB magnetic powder prepared by hydrothermal method, can solve the problem of low magnetic properties of powder compacts and achieve high magnetic properties

Active Publication Date: 2013-09-25
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The relative density of the compact is only 60%-70%, and the magnetic properties of the powder compact are very low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] 1) Dissolve neodymium nitrate, iron nitrate, and boric acid in deionized water, and add the elements neodymium, iron, and boron according to the proportion of NdFeB magnetic powder. The concentration of nitrate is controlled at 1.5mol / L, and then add surface active agent, the surfactant concentration is controlled at 0.02mol / L, uniformly stirred and mixed, and the composition ratio of NdFeB magnetic powder is Nd 35 Fe 64 B 1 (mass percent), surfactant is ethylene glycol;

[0025] 2) Add the above mixed solution to sodium hydroxide, adjust the pH value to 8, put it into the reaction kettle, heat it to 150°C for 4 hours, and obtain the precipitate;

[0026] 3) Wash the sediment three times with deionized water and twice with ethanol, put it in an oven at 80°C, keep it warm for 10 hours, and then heat-treat it in air at 500°C for 1 hour;

[0027] 4) Mix the above powder and calcium powder evenly, the mass fraction of calcium powder is 50%, perform high-temperature reduc...

Embodiment 2

[0029] 1) Dissolve neodymium nitrate, iron nitrate, dysprosium nitrate, niobium nitrate, and boric acid in deionized water, and add the elements neodymium, iron, dysprosium, niobium, and boron according to the composition ratio of NdFeB magnetic powder, and the concentration of nitrate is at 3mol / L, then add surfactant, control the concentration of surfactant at 0.1mol / L, stir and mix evenly, the composition ratio of NdFeB magnetic powder is Nd 33 Fe 62.6 B 1.2 Dy 3 Nb 0.2 (mass percent), surfactant is ethylene glycol;

[0030] 2) Add sodium hydroxide to the above mixed solution, adjust the pH value to 7.5, put it into the reaction kettle, heat it to 120°C for 6 hours, and obtain the precipitate;

[0031] 3) Wash the sediment three times with deionized water and twice with ethanol, put it in an oven at 100°C, keep it warm for 10 hours, and then heat-treat it in air at 500°C for 2 hours;

[0032] 4) Mix the above powder and calcium powder evenly, the mass fraction of calci...

Embodiment 3

[0034] 1) Dissolve neodymium nitrate, iron nitrate, dysprosium nitrate, zirconium nitrate, copper nitrate, and boric acid in deionized water, and add the elements neodymium, iron, dysprosium, zirconium, copper, and boron according to the composition ratio of neodymium iron boron magnetic powder , the concentration of nitrate is 1.5mol / L, then add surfactant, the concentration of surfactant is controlled at 0.2mol / L, stir and mix evenly, the composition ratio of NdFeB magnetic powder is Nd 39.5 Fe 55.5 B 1.1 Dy 3.6 Zr 0.2 Cu 0.1 (mass percent), surfactant is cetyltrimethylammonium bromide;

[0035] 2) Add the above mixed solution to sodium hydroxide, adjust the pH value to 11, put it into the reaction kettle, heat it to 180°C for 4 hours, and obtain the precipitate;

[0036] 3) Wash the sediment three times with deionized water and twice with ethanol, put it in an oven at 120°C, keep it warm for 6 hours, and then heat it in air at 550°C for 1 hour;

[0037] 4) Mix the above...

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Abstract

The invention discloses a method for preparing neodymium iron boron powder by means of a hydrothermal method. The method comprises the steps of (1) dissolving neodymium nitrate, ferric nitrate, nitrate of metal M, boric acid and a surface active agent into water; (2) adjusting the PH value, heating the mixture in a reaction kettle, and preserving the temperature in the reaction kettle to obtain sediment; (3) cleaning and drying the sediment, and obtaining powder in the air by means of heat treatment; (4) uniformly mixing the powder with calcium powder, carrying out high-temperature reduction heat treatment on the powder inside a vacuum-tube-type furnace, and obtaining the neodymium iron boron powder after the powder is cleaned. According to the method for preparing the neodymium iron boron powder, the sizes of granules of the sediment obtained and prepared by means of the hydrothermal method can be controlled, dispersion of the granules is good, the size of grains of the neodymium iron boron powder obtained after reduction heat treatment is from 0.2 micrometer to 20 micrometers, and the magnetic performance is higher.

Description

technical field [0001] The invention relates to a method for preparing NdFeB magnetic powder by a hydrothermal method. Background technique [0002] Rare earth NdFeB permanent magnets are the most magnetic permanent magnets in contemporary times. They not only have excellent characteristics such as high magnetic energy product and high cost performance, but also can be easily processed into various sizes. It has been widely used in aviation, aerospace, microwave communication technology, electronics, electroacoustic, electromechanical, computing technology, automation technology, automobile industry, petrochemical industry, magnetic separation technology, instrumentation, magnetic medical technology and other devices that require permanent magnetic field and in the device. [0003] At present, the research and development of sintered NdFeB permanent magnet materials has entered a new stage, represented by "two highs and one low", that is, high magnetic energy product, high ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24
Inventor 于濂清王清清韩雪王佳宁闫霞廖逸飞
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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