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Neodymium iron boron magnet sintering process

A technology of NdFeB and magnets, which is applied in the manufacture of inductors/transformers/magnets, electrical components, circuits, etc. It can solve the problems of long sintering time, high cost, high vacuum degree, etc., and achieve the effect of improving density, magnet performance and energy saving obvious effect

Inactive Publication Date: 2018-10-12
山西大缙华磁性材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, due to the complex sintering process curve, a high degree of vacuum must be maintained during the sintering process, and the sintering time is long and energy consumption is large, resulting in high cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The invention provides a sintering process for NdFeB magnets, comprising the following steps:

[0021] (1) Place the formed NdFeB magnet in a sintering furnace, heat up from room temperature to the first temperature of 800°C after 160 minutes of heating time after vacuuming, and keep it warm for 30 minutes; after vacuuming, the vacuum degree in the sintering furnace is less than or equal to 2Pa ;During the heating and constant temperature process, the water vapor and organic matter contained in the NdFeB magnet green body during the firing process are discharged;

[0022] (2) Heat up the NdFeB magnet treated in step (1) to the second temperature of 1050°C after a heating time of 65 minutes, and keep it warm for 20 minutes. Phase particle recombination, large-sized pores disappear, and magnet densification is accelerated; the NdFeB magnet is pre-fired before reaching the sintering temperature, so that the temperature gradient between the outside and the center of the NdF...

Embodiment 2

[0027] In step (4), cool in an inert gas environment, specifically cooling to 600-650°C by gas quenching, then naturally cooling to 400-450°C, and then cooling to room temperature by gas quenching again; other steps are the same as in Example 1.

Embodiment 3

[0029] While vacuuming in step (1), inert gas can be filled into the sintering furnace to stabilize the pressure of the inert gas in the furnace at 100-200Pa. After the heat preservation is completed, stop filling inert gas and vacuumize to the set vacuum degree ; The inert gas can be selected from argon, because the argon convection, the gas, volatile substances, organic matter, etc. released during the sintering process are more likely to be taken out by the argon during vacuuming, and have a good sintering atmosphere to protect the compact from being Oxidation; Other steps are with embodiment 1.

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Abstract

The invention discloses a neodymium iron boron magnet sintering process. A molded neodymium iron boron magnet is placed in a sintering furnace, the temperature is raised to 750 DEG C to 850 DEG C through 150 min to 180 min after vacuumizing is carried out, and heat preservation is carried out for 20 min to 40 min; then the temperature is raised to 1,000 DEG C to 1,050 DEG C through 60 min to 70 min, and heat preservation is carried out for 10 min to 30 min; the temperature is raised to 1,050 DEG C to 1,100 DEG C through 0 min to 10 min, and heat preservation is carried out for 300 min to 350 min; and finally inert gas is introduced for cooling, and the sintered neodymium iron boron magnet is obtained. According to the neodymium iron boron magnet sintering process, step type heating pre-sintering is adopted, the temperature gradient of the outside and the center of the magnet becomes small, the performance of the sintered magnet is improved, and the yield of the sintered magnetic is increased. The manner of gas quenching and natural cooling is adopted, neodymium iron boron compact tempering is achieved through the temperature in a furnace, and the aim of saving energy is achieved. Meanwhile, inert gas convection is utilized in the temperature raising and heat preservation process, so that gas and volatile substances released in the sintering process are taken out by the inert gas in the vacuumizing process, and compact is protected against oxidization.

Description

technical field [0001] The invention belongs to the technical field of magnet preparation, and in particular relates to a sintering process of an NdFeB magnet. Background technique [0002] NdFeB magnets are widely used in modern industry and electronic technology because of their extremely high magnetic energy product, coercive force and high energy density. The manufacturing process of NdFeB magnets is: alloy smelting→hydrogen crushing to make coarse powder→airflow grinding to fine powder→setting→isostatic pressing→sintering→surface treatment→magnetizing and using. Among them, sintering is a key step, and the quality of sintering process directly determines the performance and pass rate of NdFeB magnets. [0003] Since the NdFeB powder adsorbs a large amount of nitrogen, oxygen, carbon and other substances, these substances are released at different temperatures during the sintering process, and the released substances need to be extracted or diluted in time, otherwise th...

Claims

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Application Information

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IPC IPC(8): B22F3/10H01F41/02
Inventor 张红玲史永杰庄祖兵
Owner 山西大缙华磁性材料有限公司
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