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Sintered neodymium-iron-boron magnet and preparation method thereof

A neodymium iron boron and magnet technology, used in magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problems of reducing remanence and maximum magnetic energy product, sticking to the inner wall of equipment, powder agglomeration, etc. Effects of friction, improved orientation, improved powder lubrication

Active Publication Date: 2021-04-27
EARTH PANDA ADVANCE MAGNETIC MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional method is to add metal gallium during the smelting process, but part of the gallium will enter the main phase Nd2Fe14B and reduce the remanence and maximum energy product
The Chinese patent with the authorized notification number CN103137314B mixes gallium into the powder before the jet milling process and performs high-temperature jet milling treatment, thereby improving the remanence and maximum magnetic energy product of the NdFeB material, but there is a problem in this method: at temperature During the jet milling process above 30°C, the liquid gallium is easy to stick to the inner wall of the equipment together with the jet mill fine powder, and the powder is easy to form agglomeration
However, additives are generally organic compounds, which will introduce harmful elements carbon and oxygen when added, and are not easy to remove during subsequent sintering

Method used

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preparation example Construction

[0030] The first aspect of the present invention discloses a method for preparing a sintered NdFeB magnet, comprising the following steps:

[0031] Obtaining matrix powder: NdFeB fine powder is obtained according to the atomic ratio of the three elements of neodymium, iron and boron is 2.04~2.14:14:1;

[0032] Obtain metal flake gallium particles: crush metal gallium quick-setting flakes into metal flake gallium particles with a particle size of 0.01-0.1mm;

[0033] Obtaining mixed materials: mixing the NdFeB fine powder and the metal flake gallium particles uniformly under low temperature conditions, and the low temperature conditions refer to a temperature lower than the melting point of gallium;

[0034] Preparation of sintered NdFeB magnets: the mixture is oriented and shaped in a magnetic field at a temperature higher than 30° C., followed by isostatic pressing, sintering, and heat treatment to obtain sintered NdFeB magnets.

[0035] The present invention aims at the pro...

Embodiment 1

[0051] The three metal elements Nd, Fe, and B are mixed according to the atomic ratio of 2.04:14:1, and then smelted to make NdFeB alloy sheets. The alloy sheets are subjected to heat treatment at 1050 ° C for 3 hours in a vacuum heat treatment furnace; then After the heat treatment, the NdFeB alloy flakes are crushed to make NdFeB fine powder with an average particle size of 3 μm and an average oxygen content of 50 ppm, which is used as the matrix powder raw material.

[0052] Preparation of gallium flake metal particles: liquid gallium is sprayed onto the surface of a high-speed rotating copper roller through a nozzle with a fixed shape under a certain pressure. There is circulating cooling water in the copper roller to cool down, so that the temperature on the surface of the copper roller is maintained at 15-25 ℃. The jetted liquid metal gallium is instantly condensed into flakes or ribbons when it touches the surface of the high-speed rotating copper roller, and then broke...

Embodiment 2

[0071] The three metal elements Nd, Fe, and B are mixed according to the atomic ratio of 2.10:14:1, and then smelted to make NdFeB alloy sheets. The alloy sheets are heat-treated at 1000 ° C for 5 hours in a vacuum heat treatment furnace; then After the heat treatment, the NdFeB alloy sheet is crushed to make NdFeB fine powder with an average particle size of 3.5 μm and an average oxygen content of 150 ppm, which is used as a matrix powder raw material.

[0072] Preparation of metal flake gallium particles: After liquid gallium passes through a nozzle with a fixed shape, it is sprayed onto the surface of a high-speed rotating copper roller under a certain pressure. There is circulating cooling water in the copper roller to cool down, so that the surface temperature of the copper roller is maintained at 15-25 ℃, the ejected liquid metal gallium touches the surface of the high-speed rotating copper roller and instantly condenses into flakes or ribbons, and then breaks into partic...

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Abstract

The invention discloses a sintered neodymium-iron-boron magnet and a preparation method thereof. The preparation method includes steps that crushed neodymium-iron-boron fine powder and metal-sheet-shaped gallium particles are evenly mixed at the temperature lower than the melting point of gallium, then the even mixture is subjected to magnetic field orientation forming at the temperature higher than 30 DEG C, and the sintered neodymium-iron-boron magnet is prepared through isostatic pressing, sintering and heat treatment in sequence. The method is advantaged in that the sintered neodymium-iron-boron magnet prepared by the preparation method has higher residual magnetism, maximum magnetic energy product and coercive force, excellent magnetic performance and low impurity element content.

Description

technical field [0001] The invention belongs to the technical field of rare earth permanent magnet materials, and in particular relates to a sintered NdFeB magnet and a preparation method thereof. Background technique [0002] The continuous expansion of new energy vehicles, wind power, aerospace and many other fields has greatly promoted the rapid development of the rare earth permanent magnet industry. The emergence of high comprehensive performance permanent magnet materials has effectively promoted the development of more emerging industries. Permanent magnet materials have become one of the important material bases for promoting contemporary technology and social progress, providing a material base for new industries. [0003] As one of the main types of permanent magnet materials, sintered NdFeB is mainly used for the magnetic field generated in the air gap. The size of the magnetic field is not only related to the structure of the magnetic circuit, but more important...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0577H01F41/0253H01F41/0266
Inventor 查善顺刘友好曹玉杰黄秀莲熊永飞陈静武衣晓飞
Owner EARTH PANDA ADVANCE MAGNETIC MATERIAL