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Heat treatment process for sintered nd-fe-b

A neodymium iron boron and heat treatment technology is applied in the field of heat treatment of metal materials, and can solve the problems of poor thermal stability, low coercivity and magnetic energy product, and poor magnetic properties.

Inactive Publication Date: 2014-08-13
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a heat treatment process for NdFeB to overcome the poor thermal stability, poor magnetic properties, coercivity and The problem of low magnetic energy product

Method used

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  • Heat treatment process for sintered nd-fe-b
  • Heat treatment process for sintered nd-fe-b
  • Heat treatment process for sintered nd-fe-b

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Cut the N48 sintered NdFeB magnets produced by a magnet factory that have undergone primary tempering (tempering temperature is 900 ° C, time 2 hours) into cuboids of 20mm*20mm*12mm, and put them in a vacuum hot-press furnace. Raise the temperature in a vacuum hot pressing furnace with a heating rate of 10°C / min and a vacuum of 5×10 -3 Pa, when the temperature reaches 750°C, pressurize to 40MPa, and the pressure is loaded on the magnet for an instant, and the temperature is maintained for 1h. Cool to room temperature under this vacuum after completion. Then carry out three-stage tempering, the temperature is 550 ℃, the vacuum degree is 5×10 -3 Pa, the heating rate is 10°C / min, the holding time is 1h, the sample is cooled to room temperature under the vacuum degree, and the sample is taken out.

[0032] Table 1. Performance analysis before and after treatment

[0033]

Embodiment 2

[0035] Cut the N48 sintered NdFeB magnets produced by a magnet factory that have undergone primary tempering (tempering temperature is 900 ° C, time 2 hours) into cuboids of 20mm*20mm*12mm, and put them in a vacuum hot-press furnace. Raise the temperature in a vacuum hot pressing furnace with a heating rate of 10°C / min and a vacuum of 5×10 -3 Pa, when the temperature reaches 650°C, pressurize 20MPa, the pressure is loaded on the magnet for an instant, and keep the pressure for 1h. Cool to room temperature under this vacuum after completion. Then carry out three-stage tempering, the temperature is 550 ℃, the vacuum degree is 5×10 -3 Pa, the heating rate is 10°C / min, keep warm for 1h, cool the sample to room temperature under the vacuum degree, and take out the sample.

[0036] Table 2. Performance analysis before and after treatment

[0037]

[0038] As can be seen from Table 1 and Table 2, the magnet obtained after heat treatment using the method of the present invention...

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Abstract

The invention discloses a heat treatment process for sintered nd-fe-b, which comprises the following steps: 1) primary tempering: carrying out first-time heat treatment on sintered nd-fe-b magnets subjected to sintering under the conditions of 4-8*10<-3>Pa and 900-1000 DEG C; 2) secondary tempering: carrying out second-time heat treatment on the sintered nd-fe-b magnets under the conditions of 4-8*10<-3>Pa and 650-750 DEG C; and (3) tertiary tempering: carrying out third-time heat treatment on the sintered nd-fe-b magnets under the conditions of 4-8*10<-3>Pa and 500-600 DEG C. According to the technical scheme of the invention, nd-fe-b magnets are subjected to heat treatment by using a heat treatment method implemented through tertiary tempering treatment, the coercivity or remanence of nd-fe-b magnets are further improved through controlling the pressure and the time in the process of heating, and then the magnetic energy product of the sintered nd-fe-b magnets is increased, thereby achieving the purpose of improving the magnetic property of the magnets.

Description

technical field [0001] The invention relates to a heat treatment process for metal materials, in particular to a heat treatment process for sintered NdFeB. Background technique [0002] NdFeB magnets were invented in 1983 and have been widely used in industry in recent years. Compared with ordinary magnets, this type of permanent magnet has a very large magnetic energy product and coercivity, high cost performance, and more abundant raw materials. Therefore, this type of material has been widely used in many fields such as computers, power generation, automobiles, and aerospace. [0003] As a big rare earth country, China has rich raw material resources for NdFeB magnets and convenient transportation. However, for the production of NdFeB rare earth permanent magnet materials, it is difficult for my country to occupy a place in the world. The main reason is that the magnetic properties of rare earth permanent magnet materials in my country are deviated, and key properties su...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/18
Inventor 田然张澜庭张增超占智强张铁桥梁乐
Owner SHANGHAI JIAO TONG UNIV
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