Rare earth permanent magnetic powder and preparation method thereof

A rare-earth permanent magnet and magnetic powder technology, which is applied in the direction of magnetic materials, magnetic objects, inorganic materials, etc., can solve the particle size and distribution of the hydrogen and oxygen content of the crushed magnetic powder that does not involve hydrogen, and does not involve the crystallization state of the magnetic powder and the hydrogen and oxygen content process. parameters, and did not mention the hydrogen explosion process parameters and process of crushing rare earth alloy blocks, etc., to achieve the effect of favorable magnetic field orientation, low oxygen content, and increased coercive force

Active Publication Date: 2009-10-07
GRIREM ADVANCED MATERIALS CO LTD
View PDF15 Cites 20 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In 1999, the Japanese patent JP11050110 disclosed an alloy powder for the preparation of rare earth magnets, using a rapid solidification technology to first prepare R-T-B flakes, and then at 0.10kg / cm 2 Hydrogen fragmentation under hydrogen pressure or above, but the crystallization state and hydrogen and oxygen content of the magnetic powder are not mentioned
In 2003, Japanese patent JP2003297622 disclosed a hydrogen absorption, hydrogenation ball milling method and a preparation process of rare earth permanent magnets. It mainly disclosed the gas composition of hydrogen absorption and dehydrogenation, and did not involve the crystallization state of magnetic powder, hydrogen and oxygen content and specific process parameters.
In 2004, Japanese patent JP2004285480 disclosed a method for preparing alloy powder for manufacturing Nd-Fe-B permanent magnets. The specific process is annealing at 800-1100°C, and ball milling in nitrogen after hydrogenation and dehydrogenation. The patent mainly discloses The process parameters and atmosphere of the ball mill are mentioned, but the crystallization state, hydrogen and oxygen content and process of the magnetic powder are not mentioned.
In 2006, the Japanese patent JP2006283095 disclosed a production method of rare earth alloy powder. The specific process is ball milling after hydrodehydrogenation. The patent mainly discloses the particle size of the rare earth alloy magnetic powder, but does not mention the crystallization state of the magnetic powder and the hydrogen and oxygen content.
Japanese patent JP2000303107 in 2000 and Japanese patent JP2003082406 in 2003 disclosed a hydrogenation device and rare earth magnetic powder and magnets prepared by it, mainly disclosing a hydrogenation device, without mentioning the hydrogen explosion process parameters and process of crushing rare earth alloy blocks
However, none of them involve the hydrogen and oxygen content, crystal shape, particle size and distribution in the composition of hydrogen crushing magnetic powder (HD magnetic powder), and these parameters directly determine the magnetic properties of hydrogen crushing magnetic powder

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] The preparation process of the rare earth magnetic powder in this embodiment is as follows: batching, induction melting the prepared raw materials in the crucible, and then casting them on the rotating water-cooled roller through the casting tank to form an alloy casting with a thickness of 0.3 mm and a columnar crystal proportion of 93% in the structure. piece. Put the cast piece into the hydrogen explosion furnace, vacuumize it, fill it with hydrogen, keep the hydrogen pressure constant at 0.3MPa, and absorb hydrogen at 25°C. After hydrogen absorption is completed, dehydrogenation is carried out under vacuum at 580°C to obtain rare earth magnetic powder. The particle size of the obtained magnetic powder is between 25 μm and 1000 μm, accounting for 90% of the total amount. The crystal form of the magnetic powder is mainly uniform columnar crystals, and the volume ratio of columnar crystals accounts for 90%. The analysis of its composition is shown in Table 1-1. Sinte...

Embodiment 2

[0042] The preparation process of the rare earth magnetic powder in this embodiment is as follows: batching, induction smelting the prepared raw materials in the crucible, and then casting them on the rotating water-cooled roller through the casting tank to form a cast sheet with a thickness of 0.1mm and columnar crystals accounting for 80% of the structure. . Put the cast piece into the hydrogen explosion furnace, vacuumize it, fill it with hydrogen, keep the hydrogen pressure constant at 0.3MPa, and absorb hydrogen at 125°C. After hydrogen absorption is completed, dehydrogenation is carried out under vacuum at 450°C to obtain rare earth magnetic powder. The particle size of the obtained magnetic powder between 25 μm and 1000 μm accounts for 88% of the total amount. The crystal form of the magnetic powder is mainly uniform columnar crystals, and the volume ratio of columnar crystals accounts for 75%. The analysis of its composition is shown in Table 2-1. Sintered NdFeB magn...

Embodiment 3

[0048] The preparation process of the rare earth magnetic powder in this embodiment is as follows: batching, induction smelting the prepared raw materials in the crucible, and then casting them on the rotating water-cooled roller through the casting tank to form a cast sheet with a thickness of 0.25 mm and a columnar crystal in the structure accounting for 85%. . Put the cast piece into the hydrogen explosion furnace, vacuumize it, fill it with hydrogen, keep the hydrogen pressure constant at 0.4MPa, and absorb hydrogen at 80°C. After the hydrogen absorption is completed, dehydrogenation is carried out under vacuum at 350°C to obtain rare earth magnetic powder. The particle size of the obtained magnetic powder between 25 μm and 1000 μm accounts for 88% of the total amount. The crystal form of the magnetic powder is mainly uniform columnar crystals, and the volume ratio of columnar crystals accounts for 85%. The analysis of its composition is shown in Table 3-1. Sintered NdFe...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
sizeaaaaaaaaaa
sizeaaaaaaaaaa
sizeaaaaaaaaaa
Login to view more

Abstract

The invention discloses a rare earth permanent magnetic powder and a preparation method thereof. The magnetic powder is a multi-crystal powder containing columnar crystal and comprises the following component of R-T-B, wherein the R represents at least one kind of 17 kinds of elements including Sc and Y and accounts for 26.1-37.0 wt percent, the B represents at least boron or hydrogen and accounts for 0.8-1.5 wt percent, and the balance is T, and the T represents Fe and at least one kind of other transitional elements including Al, Ga, Si, Ge, Sn, Pb, Mg and Ca. The magnetic powder has high proportion of the column crystal, uniform particle size distribution and low oxygen content, and the prepared sintered permanent neodymium-iron-boron magnet has large coercive force and high magnetic energy product. The preparation method of the rare earth permanent magnetic powder comprises the following steps of precursor alloy preparation, hydrogen absorption or precursor alloy preparation, hydrogen absorption and dehydrogenation.

Description

technical field [0001] The invention belongs to the field of rare earth permanent magnet materials, and relates to an R-T-B series permanent magnet powder and a preparation method thereof. technical background [0002] The preparation process of sintered NdFeB magnets generally includes five major steps: ingot / cast sheet→coarse crushing→jet milling→press molding→sintering, among which coarse crushing and jet milling belong to the powder making process. The performance of magnetic powder is crucial to the preparation of high-performance NdFeB magnets. Generally, it is required that the magnetic powder particles should be evenly distributed, and should be single-crystal particles as much as possible, with few crystal defects and low impurities and oxygen content. In the powder making process, coarse crushing has an important impact on the performance of the magnetic powder. Proper coarse crushing of the master alloy is the prerequisite for ensuring the crystal shape of the ma...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/053H01F1/06B22F9/00
Inventor 李红卫于敦波李扩社颜世宏胡权霞王鹏飞
Owner GRIREM ADVANCED MATERIALS CO LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap