NdFeB (neodymium iron boron) magnetic material with ultrafine powder and preparation method thereof

A magnetic material and ultrafine powder technology, which is applied in the direction of magnetic materials, magnetic objects, and inorganic materials, can solve the problems of ultrafine powder storage, danger and difficulty in use, low residual magnetization, and easy oxidation and combustion. Achieve the effects of improving comprehensive economic benefits, inhibiting grain growth, and protecting the environment

Inactive Publication Date: 2013-06-12
辽宁恒德磁业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In the production process of sintered Nd-Fe-B, due to the use of fluidized bed collision airflow milling (milling) machine in the powder making process, in addition to normal powder, 2-3% of ultra-fine powder with finer particle size will be produced The characteristics of these ultrafine powders are: high rare earth content, easy oxidation and combustion, and low residual magnetization. These characteristics cause certain dangers and difficulties in storage and use of ultrafine powders.

Method used

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  • NdFeB (neodymium iron boron) magnetic material with ultrafine powder and preparation method thereof
  • NdFeB (neodymium iron boron) magnetic material with ultrafine powder and preparation method thereof
  • NdFeB (neodymium iron boron) magnetic material with ultrafine powder and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Configure conventional alloys, the mass percentage composition of raw materials is: Pr-Nd-Dy: 25.5%, La-Ce: 5%, B: 1.0%, Fe: 67.5%, Al: 0.8%, Cu: 0.2%, using SC- Preparation of conventional alloy coarse particle powder by HD process: at 3.0×10 -1 Melted into thin slices with a thickness of 0.25-0.35mm under Pa vacuum, the thin slices absorb hydrogen at room temperature for 3.0 hours in the reaction kettle of the hydrogen crushing furnace, and then heat to 600°C for 6.0 hours to dehydrogenate to prepare a particle size of 60-80 mesh. Coarse powder for use;

[0029] The ultra-fine powder produced by the jet mill is uniformly mixed in the mixer for 1-3 hours.

[0030] The above-mentioned alloy coarse particle powder is ground by a QLM-400 jet mill under a working pressure of 0.7MPa to a fine powder with an average particle size of 3.0-3.5μm; %) ratio, add 15-20% of the above-mentioned superfine powder to the conventional alloy powder, and mix evenly in the mixer for 2 ho...

Embodiment 2

[0036] The difference from Example 1 is that the addition ratio of superfine powder is 10%, and other process routes are the same as in Example 1, and the test data are shown in Table 1.

[0037] The topography diagram relevant to this embodiment is similar to that of Embodiment 1, omitted.

[0038] as the picture shows, Figure 1-3 The microscope (SEM) topography in the figure is the scanning electron microscope (SEM) topography of the magnet after adding 10% (wt%) ultrafine powder and sintering; Figure 2-3The curve in is the magnetization characteristic curve of 10% (wt%) superfine powder addition, which is shown by No. 3 in the test data in Table 1. Compared with the curve without superfine powder: the coercive force of the finished product is increased by 32.6 %, the squareness increased by 9.1%, and the residual magnetism decreased by 4.5%.

Embodiment 3

[0040] The difference from Example 1 is that the addition ratio of superfine powder is 15%, and other process routes are the same as in Example 1, and the test data are shown in Table 1.

[0041] The topography diagram relevant to this embodiment is similar to that of Embodiment 1, omitted.

[0042] as the picture shows, Figure 1-4 The microscope (SEM) topography in the figure is the scanning electron microscope (SEM) topography of the magnet after adding 15% (wt%) ultrafine powder and sintering; Figure 2-4 The curve in is the magnetization characteristic curve of 15% (wt%) superfine powder addition, which is shown in No. 4 of the test data in Table 1. Compared with the curve without superfine powder: the coercive force of the finished product is improved 38.3%, the squareness increased by 10.6%, and the residual magnetism decreased by 7.3%.

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Abstract

The invention discloses a NdFeB (neodymium iron boron) magnetic material with ultrafine powder and a preparation method thereof. The ultrafine powder generated through air-current mill is added into normal magnetic powder which comprises certain amount of Pr-Nd-Dy, mixed rare earth (La-Ce), B, Al, Cu and the balance of Fe to prepare the NdFeB product. Proper addition can enrich rare earth phase; the product is prevented from being oxidized because of over low total amount of rear earth; a crystal boundary is strengthened, and the coercivity is improved; and NdFeB crystalline grains are prevented from being grown in a sintering process, the uniformity of the grains in the product is guaranteed, and the squareness of the product is improved. The granularity of the ultrafine powder is less than 2 mu m, the grains are large in specific surface area and few in defects, so that the surface activity is high, chemical reaction speed is high, the solubility is high, particularly the coercivity is very high, the sintering temperature of a magnetic body is reduced, and the coercivity is increased.

Description

technical field [0001] The invention relates to the technical field of manufacturing NdFeB permanent magnet materials, in particular to an NdFeB magnetic material with ultrafine powder and a preparation method thereof. Background technique [0002] NdFeB magnetic material, as the latest result of the development of rare earth permanent magnet materials, is known as the "Magnetic King" because of its excellent magnetic properties. NdFeB magnetic materials are alloys of neodymium, boron, iron, etc., also known as magnets. NdFeB has extremely high magnetic energy product and coercive force, and the advantages of high energy density make NdFeB permanent magnet materials widely used in modern industry and electronic technology, so that instruments, electroacoustic motors, magnetic separation Miniaturization, weight reduction, and thinning of equipment such as magnetization are possible. [0003] In the production process of sintered Nd-Fe-B, due to the use of fluidized bed col...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F1/08B22F9/04B22F3/16
Inventor 杨延华李嘉颜廷顺
Owner 辽宁恒德磁业有限公司
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