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Preparation method of neodymium iron boron magnet

A magnet manufacturing method, NdFeB technology, applied in the direction of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problems of wasting heavy rare earth resources, difficult to control film uniformity, and low magnetization intensity, and achieve control Film thickness and film uniformity, easy film thickness and film uniformity, good effect of film thickness uniformity

Active Publication Date: 2012-12-19
GRIREM ADVANCED MATERIALS CO LTD
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AI Technical Summary

Problems solved by technology

However, although the existing NdFeB permanent magnet has a high magnetic energy product, it has fatal shortcomings: low Curie temperature and working temperature, poor thermal stability, and its magnetic properties deteriorate sharply when the temperature is higher than 150 °C
However, the addition of Tb and Dy brings two serious problems: (1) Most of Tb and Dy enter the grains to form Tb with Fe and B elements 2 Fe 14 B or Dy 2 Fe 14 B compound, the magnetization of this type of compound is much lower than the main phase Nd of NdFeB permanent magnet 2 Fe 14 B, will greatly reduce the remanence and magnetic energy product of the material; (2) Tb, Dy and other heavy rare earth elements are expensive and are scarce resources, and their storage capacity is only 1 / 10 to 1 / 100 of Nd, and the ore veins are limited to several production is very limited
But the two have one thing in common: that is, when preparing high coercive force sintered NdFeB magnets, heavy rare earth elements such as Tb and Dy are pre-added in the master alloy, which not only wastes heavy rare earth resources, increases production costs, but also sacrifices Partial remanence and energy product of magnets
[0005] At present, there are related patent reports on improving the coercive force of magnets in China. The reports are nothing more than adding Tb and Dy in two ways, one is through traditional smelting, and the other is through mixing during powder making. 2006-158500) adopts vacuum evaporation method for magnet coating to improve the comprehensive performance of magnets. The disadvantages are as follows: (1) the equipment is expensive (2) the material utilization rate is low (3) the uniformity of the film is difficult to control, and it is difficult to Realize industrialization (4)R 2 Elements only illustrate Tb, Dy, Gd, Ho are not mentioned

Method used

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  • Preparation method of neodymium iron boron magnet
  • Preparation method of neodymium iron boron magnet
  • Preparation method of neodymium iron boron magnet

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Embodiment 1

[0040] The preparation method of this embodiment is as follows: processing into 10×10×3mmR 1 FeMB magnet. R 2 Plated onto the magnet surface by the present invention, R 1 FeMB as cathode, R 2 As the anode, the specific parameters used in the electrodeposition method are: the electrolyte is urea 35wt%, NaCl13wt%, KBr is 2wt%, the balance is formamide organic solution, the main salt DyCl 3 The concentration is 0.2mol / L, and the current density at constant potential is 6000A m -2 , after coating for 2000s, stop coating, the film thickness is 3.0 μm, the coating R of the present invention 2 The SEM image of the membrane is shown in figure 2 shown in figure 2 , in the magnet R 1 On the surface of FeMB (also known as matrix) 6, R is plated by electrodeposition 2 Film 5, the heat treatment process is 800 ° C, cooling after 4 hours of heat preservation, the cooling rate is 500 ° C / h, and then 300 ° C for 1 hour, natural cooling at room temperature, the magnetic properties ...

Embodiment 2

[0046] The preparation method of this embodiment is as follows: processing into 10×10×3mmR 1 FeMB magnet. R 2 Plated onto the magnet surface by the present invention, R 1 FeMB as cathode, R 2 As the anode, the specific parameters used in the electrodeposition method are: the electrolyte is urea 33wt%, NaCl13wt%, KBr is 2wt%, the balance is formamide organic solution, the main salt TbCl 3 The concentration is 0.2mol / L, and the current density at constant potential is 6000A m -2 , after coating for 2000s, stop the coating, the film thickness is 3.0μm, the heat treatment process is 800°C, keep warm for 4h and then cool, the cooling rate is 500°C / h, then keep warm at 300°C for 1h, cool naturally at room temperature, and test the magnetic properties of the sample. For comparison, we use the traditional smelting method to add Tb to make magnets. The properties of the magnets are shown in Table 2-1. ICP analysis of the composition of the magnets is shown in Table 2-2. Correspond...

Embodiment 3

[0052] The preparation method of this embodiment is as follows: processing into 10×10×3mmR 1 FeMB magnet. R 2 Plated onto the magnet surface by the present invention, R 1 FeMB as cathode, R 2 As the anode, the specific parameters used in the electrodeposition method are: the electrolyte is 30wt% urea, 12wt% NaCl, 1.5wt% KBr, and the balance is formamide organic solution, the main salt TbF 3 The concentration is 0.2mol / L, and the current density at constant potential is 3000A m -2 After coating for 1800s, stop the coating, the film thickness is 5.0μm, the heat treatment process is 800°C, keep warm for 4h and then cool, the cooling rate is 500°C / h, then keep warm at 300°C for 1h, cool naturally at room temperature, and test the magnetic properties of the sample. For comparison, we use the traditional smelting method to add Tb to make magnets. The properties of the magnets are shown in Table 3-1. ICP analysis of the composition of the magnets is shown in Table 3-2. Correspon...

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Abstract

A preparation method of neodymium iron boron magnet is disclosed. The composition general formula of the magnet provided by the invention is R1R2FeMB, wherein R1 is at least one element selected from the group consisting of Nd, Pr, La, Ce, Sm, Sc, Y and Eu, having a content of 23 to 35 wt%; R2 is at least one element selected from the group consisting of Tb, Dy, Gd, and Ho, having a content of 0.1 to 5 wt%; M represents transition group metal with the exception of Fe, having the content of 0.01 to 5 wt%; B represents simple substance boron, having the content of 0.8 to 1.2 wt%; the balance isFe and the other inevitable impurities. The preparation method of neodymium iron boron magnet provided by the invention works in such a manner that: one or more elements in the R2 are plated to the surface of the magnet, the metal R2 is diffused into the interior of the magnet by primary high temperature heat treatment, and imbalance organization and internal stress brought by the high temperature treatment are eliminated through secondary low temperature tempering. Low temperature molten salt electrodeposition method is employed to plate films. The present invention is advantageous in greatly improving the production efficiency, reducing the dosage of the heavy rare earth during preparation process of magnet, saving rare earth resource, and obtaining high coercivity without reducing remanent magnetism and magnetic energy product of a magnet.

Description

technical field [0001] The invention relates to a preparation method of an NdFeB magnet, belonging to the technical field of magnetic materials. Background technique [0002] Neodymium iron boron (NdFeB) permanent magnet has the characteristics of small size, light weight and strong magnetism. It is the magnet with the best performance and price ratio so far, and is known as the king of magnetism in the magnetic field. NdFeB permanent magnet materials are widely used in high-tech fields such as computers, communications, and national defense due to their excellent performance, and new application fields continue to emerge. Its development and application level has become a symbol of a country's national strength and development level. Motors are the main application fields of NdFeB permanent magnets. Among them, the application in hybrid electric vehicles (HEV) is particularly eye-catching. Driving motors and generators, and electric power steering (EPS) have entered the pra...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057H01F41/02
Inventor 闫文龙李宗安于敦波颜世宏李红卫王祥生陈德宏庞思明袁永强
Owner GRIREM ADVANCED MATERIALS CO LTD
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