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Sintered R-Fe-B permanent magnet and its production method

一种制造方法、永磁体的技术，应用在电感/变压器/磁铁制造、磁性物体、永久磁铁等方向，能够解决环状磁体磁特性偏差大、制造成本高、端部易引入裂纹等问题

Inactive Publication Date: 2009-06-03
PROTERIAL LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the thermoplastic processing of the hot-pressed body in an inert gas atmosphere is carried out at a relatively low temperature of about 700-800°C in order not to coarsen the grains, it must be performed at an extremely low speed in order to prevent cracks.
Although it varies depending on the size of the magnet, the time required for one thermoplastic processing is usually 10 to 30 minutes, and the productivity is low as an industrial manufacturing method for permanent magnets
In addition, since the press-worked body manufactured in this way is easy to introduce cracks at the end, it is necessary to cut out the crack occurrence part.
From these reasons, the manufacturing cost of this manufacturing method is high
In addition, the magnetic properties of the obtained ring magnet have large variations
The degree of radial anisotropy depends on the amount of deformation during hot plastic processing, but there is a problem that the deviation of the surface magnetic flux density becomes large especially for small-diameter or long-length products that have high resistance to hot plastic processing

Method used

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  • Sintered R-Fe-B permanent magnet and its production method
  • Sintered R-Fe-B permanent magnet and its production method
  • Sintered R-Fe-B permanent magnet and its production method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0093] Based on mass, it is made of 17.6% Nd, 7.9% Pr, 5% Dy, 1.1% B, 0.08% Al, 1.5% Co, 0.1% Cu, 0.01% P, 0.01% 0. An ingot composed of 0.004% C, 0.006% N, and the rest being Fe. This ingot is pulverized to form a coarse powder with a particle diameter of 20 to 500 μm. The composition of the coarse powder was analyzed, and the results were as follows: 17.5% Nd, 7.7% Pr, 5% Dy, 1.1% B, 0.08% Al, 1.5% Co, 0.1% Cu, 0.01% P , 0.15% of 0, 0.015% of C, 0.006% of N, and the rest is Fe.

[0094] After putting 100 kg of this coarse powder into a jet mill, the gas in the jet mill was replaced with Ar gas so that the oxygen concentration was substantially 0%. Next, nitrogen gas was introduced so that the nitrogen concentration in the Ar gas was 0.005%. In this atmosphere, with a pressure of 6.9×10 5 Pa (about 7.0kgf / cm 2 ), and the coarse powder supply per hour is 12kg / h to finely pulverize the coarse powder. A container filled with mineral oil was installed at the fine powder rec...

Embodiment 2

[0099] Based on mass, it is made of 19.8% Nd, 8.9% Pr, 1.3% Dy, 1.1% B, 0.10% Al, 2.5% Co, 0.2% Nb, 0.08% Ga, 0.01% 0. An ingot composed of 0.003% C, 0.005% N, and the rest being Fe. The ingot is pulverized to form a coarse powder with a particle diameter of 20 to 500 μm. The composition of the coarse powder was analyzed, and the results were as follows: 19.7% Nd, 8.8% Pr, 1.3% Dy, 1.1% B, 0.10% Al, 2.5% Co, 0.2% Nb, 0.08% Ga , 0.12% of 0, 0.013% of C, 0.007% of N, and the rest is Fe.

[0100] 454 g of the aqueous solution which melt|dissolved 5 mass % sodium hypophosphite in pure water was mixed with this coarse powder 100k, and it dried in vacuum. Analyze the composition of the coarse powder after drying, the result is 19.7% Nd, 8.8% Pr, 1.3% Dy, 1.1% B, 0.10% Al, 2.5% Co, 0.2% Nb, 0.08% Al Ga, 0.008% of P, 0.16% of O, 0.013% of C, 0.009% of N, and the rest is Fe. The coarse powder was finely pulverized in the same manner as in Example 1. The average particle diameter o...

Embodiment 3

[0108] Based on mass, 19.85% of Nd, 8.95% of Pr, 1.00% of Dy, 1.02% of B, 0.10% of Al, 2.00% of Co, 0.10% of Cu, 0.15% of 0, 0.04% of C , 0.02% N, and the rest are the coarse powder used for the R-Fe-B permanent magnet composed of Fe and put it into the jet mill, replace the gas therein with nitrogen, and press 6.9×10 5 Pa(7.0kgf / cm 2 ), the feed rate of coarse powder is 15kg / h for fine pulverization. The obtained fine powder was directly recovered in mineral oil ("Su-Pa-Zur PA30", manufactured by Idemitsu Kosan Co., Ltd.) installed at the outlet of the jet mill without being exposed to the air to obtain a slurry.

[0109] A 5% by mass sodium hypophosphite glycerol solution was previously mixed with this mineral oil so that the ratio of sodium hypophosphite to the mineral oil would be 0.1% by mass. The mass ratio of mineral oil and coarse powder in the slurry is 1:3. The average particle diameter of the obtained fine powder was 4.5 μm. The slurry made in this way is inject...

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Abstract

A method for producing a sintered permanent magnet comprises the steps of (a) pulverizing a rare earth magnet material to fine powder, and recovering said fine powder directly in a mineral oil, a synthetic oil or their mixture to form a slurry, (b) injecting said slurry under pressure into a die cavity, in which said slurry is wet-molded in a magnetic field, (c) heating the resultant green body under reduced pressure to remove said mineral oil, said synthetic oil or their mixture from said green body, and (d) sintering said green body in vacuum, wherein an axial direction of an aperture open in a cavity of said die for injecting said slurry under pressure is deviated from a center of a center core in said die.

Description

[0001] This application is a divisional application of the application with the filing date of October 8, 2003, the application number of 200310100706.7, and the title of the invention "sintered R-Fe-B permanent magnet and its manufacturing method". technical field [0002] The present invention relates to a method for manufacturing a high-performance sintered R-Fe-B permanent magnet having improved coercive force iHc by containing a desired amount of P, in particular to a radial magnet with excellent surface magnetic flux density uniformity. An effective method of manufacturing anisotropic high-performance sintered R-Fe-B permanent magnets. Background technique [0003] For a long time, R-Fe-B permanent magnets have been produced by the so-called dry forming method of forming dry fine powder in a metal mold while applying an external magnetic field. In the dry forming method, when the raw material coarse powder is finely pulverized by a jet mill, a small amount of oxygen is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02C22C1/04C22C33/02C22C38/00B22F3/10H01F1/057H01F1/08H01F7/02
Inventor 藤森信彦园田和博塚田高志松嶋纯二木村靖菊地党
Owner PROTERIAL LTD
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