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Method for preparing high coercive force manganese-bismuth magnetic powder by doping cobalt nano-particles

A coercivity manganese-bismuth and cobalt nanotechnology, which is applied in the field of preparing manganese-bismuth magnetic powder with high coercivity, can solve the problems of unfavorable application of manganese-bismuth permanent magnet materials and low coercivity, and achieve high surface activity and high coercivity. Improvement, small size effect

Inactive Publication Date: 2013-02-06
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the limitation of intrinsic magnetic properties, the coercive force of single-phase manganese-bismuth permanent magnet powder is still lower than that of commonly used permanent magnet materials such as samarium-cobalt, especially at room temperature. The application is very unfavorable

Method used

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  • Method for preparing high coercive force manganese-bismuth magnetic powder by doping cobalt nano-particles
  • Method for preparing high coercive force manganese-bismuth magnetic powder by doping cobalt nano-particles

Examples

Experimental program
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Effect test

Embodiment 1

[0018] Raw material manganese and bismuth are mixed according to the ratio of 1.05:1 (molar ratio), and the alloy is made by magnetic levitation melting technology. The alloy is heat-treated under vacuum conditions, and the process conditions of the heat treatment are: temperature 280° C., time 72 hours. The annealed alloy was subjected to rolling ball milling under the protection of acetone, the ball-to-material ratio was 3:1, and the ball milling time was 6 hours to obtain 4-micron single-phase manganese-bismuth magnetic powder. Add cobalt nanoparticles with an average particle size of 20 nanometers and a weight ratio of 5% to the manganese-bismuth magnetic powder, and mix the two evenly. The mixed powder was subjected to high-energy ball milling under the protection of argon, the ball-to-material ratio was 20:1, and the ball-milling time was 2 hours to finally obtain manganese-bismuth magnetic powder.

Embodiment 2

[0020] Raw material manganese and bismuth are mixed according to the ratio of 1.05:1 (molar ratio), and the alloy is made by magnetic levitation melting technology. The alloy is heat-treated under vacuum conditions, and the process conditions of the heat treatment are: temperature 295° C., time 36 hours. The annealed alloy was subjected to rolling ball milling under the protection of acetone, the ball-to-material ratio was 3:1, and the ball milling time was 4 hours to obtain 6-micron single-phase manganese-bismuth magnetic powder. Add cobalt nanoparticles with an average particle size of 100 nanometers and a weight ratio of 15% to the manganese-bismuth magnetic powder, and mix the two evenly. The mixed powder was subjected to high-energy ball milling under the protection of argon, the ball-to-material ratio was 20:1, and the ball milling time was 4 hours to finally obtain manganese-bismuth magnetic powder.

Embodiment 3

[0022] Raw material manganese and bismuth are mixed according to the ratio of 1.05:1 (molar ratio), and the alloy is made by magnetic levitation melting technology. The alloy is heat-treated under vacuum conditions, and the process conditions of the heat treatment are: temperature 290° C., time 48 hours. The annealed alloy was subjected to rolling ball milling under the protection of acetone, the ball-to-material ratio was 3:1, and the ball milling time was 5 hours to obtain 5-micron single-phase manganese-bismuth magnetic powder. Add cobalt nanoparticles with an average particle size of 50 nanometers and a weight ratio of 10% to the manganese-bismuth magnetic powder, and mix the two evenly. The mixed powder was subjected to high-energy ball milling under the protection of argon, the ball-to-material ratio was 20:1, and the ball-milling time was 3 hours to finally obtain manganese-bismuth magnetic powder.

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Abstract

The invention discloses a method for preparing high coercive force manganese-bismuth magnetic powder by doping cobalt nano-particles, belonging to the technical field of manganese-bismuth magnetic powder. The method comprises the steps of: preparing manganese-bismuth alloy by adopting a magnetic suspension melting technology; carrying out heat treatment on the manganese-bismuth alloy under a vacuum condition; preparing the manganese-bismuth alloy after the heat treatment into alloy powder by utilizing a rolling ball-milling technology; preparing cobalt nano-particles by adopting a physic vapor-phase deposition technology; uniformly mixing the manganese-bismuth alloy powder with the cobalt nano-particles; and performing high energy ball milling on the mixed powder under the protection of argon to finally obtain the high coercive force manganese-bismuth magnetic powder. In comparison with manganese-bismuth magnetic powder without doping of the cobalt nano-particles prepared by the same method, the invention utilizes the characteristics of small size of the cobalt nano-particles and high surface activity to the cobalt nano-particles to enter into manganese-bismuth alloy crystal lattices through the high energy ball milling, so that the coercive force of the finally obtained cobalt nano-particle doped type manganese-bismuth alloy magnetic powder is improved obviously by 50-100%.

Description

technical field [0001] The invention relates to a method for preparing manganese-bismuth magnetic powder with high coercive force, belonging to the technical field of manganese-bismuth magnetic powder. Background technique [0002] Manganese-bismuth is a class of functional materials with good magnetic properties, and has broad application prospects in many fields such as magneto-optical storage and permanent magnet motors. [0003] In recent years, with the rapid development of emerging environmental protection industries such as wind power generation and electric vehicles, permanent magnet materials as key basic materials have attracted widespread attention. At present, the commonly used permanent magnet materials such as NdFeB magnets have poor temperature characteristics, that is, the magnetic properties of the magnets drop sharply with the increase of temperature, so they cannot be applied to products that have higher requirements for operating temperature. The mangane...

Claims

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Application Information

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IPC IPC(8): B22F9/00C22C1/02C22C22/00B22F9/04B22F9/14B22F1/00
Inventor 岳明张东涛耿文甜刘卫强张久兴
Owner BEIJING UNIV OF TECH
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