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A kind of ultra-high coercive force sintered NdFeB magnet and its preparation method

A technology of coercive force and NdFeB, which is applied in the field of ultra-high coercive force sintered NdFeB magnets and its preparation, can solve the problems of rapid decline in magnet remanence, achieve optimized grain boundary phase, simple operation, high remanence Effects of magnetism and energy product

Active Publication Date: 2016-06-29
ZHEJIANG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But when the amount added is high, the remanence of the magnet drops too fast

Method used

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Effect test

preparation example Construction

[0019] The steps of a preparation method of an ultra-high coercive force sintered NdFeB magnet are as follows:

[0020] 1) Follow the low H A main alloy and high H A The ingredients of the main alloy are batched separately, and the flakes of the two alloys with a thickness of 0.2~0.5mm are obtained by using the quick-setting casting strip technology respectively; the flakes of the two alloys are mixed, and the average particle size is made by hydrogen breaking and jet milling 3~5μm magnetic powder;

[0021]2) The grain boundary additive phase is prepared by smelting, coarse crushing, and ball milling in sequence, or the grain boundary additive phase powder is prepared by rapid solidification casting belt, hydrogen breaking, and jet milling in sequence. The average particle size of the grain boundary additive phase powder is 0.01~ 3.0μm;

[0022] 3) Mix the grain boundary additive phase powder with the magnetic powder obtained in step 1) under the protection of nitrogen, a...

Embodiment 1

[0026] 1) It will be calculated in mass percentage, and the composition is (PrNd) 27.79 B 0.97 Fe 71.24 and (PrNd) 26.5 Dy 8.0 B 0.97 Fe bal co 1.0 Al 0.3 Cu 0.15 Nb 0.3 The main alloys are prepared separately, and the prepared raw materials are prepared by using the quick-setting flake technology to obtain a flake thickness of 0.2~0.5mm. After mixing the flakes of the two alloys at a ratio of 5:5, they are made by hydrogen breaking and jet milling. Main alloy magnetic powder with an average particle size of 3.0 μm;

[0027] 2) Add 5.0% Dy 2 o 3 The powder is mixed with the main alloy powder, and 0.2% of aviation gasoline and 0.2% of antioxidant are added, mixed evenly under the protection of nitrogen, then oriented and formed under a 2T magnetic field, and made into a green body by 17MPa cold isostatic pressing;

[0028] 3) The green body is sintered in a vacuum sintering furnace at a sintering temperature of 1020° C. and kept for 6 hours; then the primary heat tr...

Embodiment 2

[0031] 1) It will be calculated in mass percentage, and the composition is (PrNd) 28.3 Dy 0.5 B 0.96 Fe 70.62 and (PrNd) 25.5 Dy 8.0 B 0.97 Fe bal co 1.0 Al 0.3 Cu 0.15 Nb 0.3 The main alloys are prepared separately, and the prepared raw materials are prepared using the quick-setting flake technology to obtain a flake thickness of 0.2~0.5mm. After mixing the flakes of the two alloys at a ratio of 5:5, they are made into an average by hydrogen breaking and jet milling. Main alloy magnetic powder with a particle size of 4.0 μm;

[0032] 2) Add 3.0% DyH x The powder is mixed with the main alloy powder, and 0.2% of aviation gasoline and 0.2% of antioxidant are added, mixed evenly under the protection of nitrogen, oriented and formed under a 3T magnetic field, and made into a green body by 17MPa cold isostatic pressing;

[0033] 3) Put the green body in a vacuum sintering furnace for sintering, the sintering temperature is 1080°C, heat preservation

[0034] 1h; then ca...

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Abstract

The invention discloses an ultrahigh-coercivity sintered neodymium-iron-boron magnet and a preparation method thereof. The ultrahigh-coercivity sintered neodymium-iron-boron magnet comprises a main phase and a crystal boundary adding phase. The main phase comprises low-HA main alloy and high-HA main alloy. The high magnetocrystalline anisotropy field HA main alloy and the low-HA main alloy are used as the main phase, so that the heavy rare earth element diffuses from the high-HA phase to the low-HA phase in the sintering and heat treatment process to initially improve the coercivity; in addition, alloy components and the preparation technology can be controlled at the same time, the content of Nd2Fe14B in the magnet is improved, and it is ensured that the magnet has the high magnetic energy product. The crystal boundary adding phase can further achieve crystalline grain surface magnetic hardening and improve the coercivity, the microscopic structure is optimized, and the coercivity is further improved. The preparation method of the ultrahigh-coercivity sintered neodymium-iron-boron magnet has the advantages of both a traditional dual alloy method and a single alloy crystal boundary adding method, and is easy to operate and suitable for mass production of ultrahigh-coercivity high-residual-magnetism sintered neodymium-iron-boron magnets.

Description

technical field [0001] The invention relates to the technical field of rare earth permanent magnet materials, in particular to an ultra-high coercivity sintered NdFeB magnet and a preparation method thereof. Background technique [0002] As the third-generation rare earth permanent magnet, sintered NdFeB has been widely used in electronic information, medical treatment, transportation, wind power generation, aerospace and other fields due to its good magnetic properties since its appearance in 1983. At present, the highest remanence of sintered NdFeB is 15.55kGs, which is 96% of the theoretical value; the highest magnetic energy product is 59.5MGOe, which is 92% of the theoretical value; however, the coercive force is only 1 / 6~1 / 3 of the theoretical value , cannot meet the needs of high-temperature fields such as electric motors and hybrid vehicles, so how to prepare high-coercivity magnets has become a hot research direction. [0003] At present, the coercive force of sint...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057H01F7/02H01F41/02B22F3/16
Inventor 严密高翠金佳莹王新华
Owner ZHEJIANG UNIV
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