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Method for preparing high-performance sintered Nd-Fe-B magnet

A neodymium iron boron and magnet technology, used in magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problems that vacuum and pressure cannot be achieved, pressure cannot be applied, and vacuum cannot be evacuated, and the sintering temperature cannot be reduced. , The effect of increasing magnet density and uniform distribution

Inactive Publication Date: 2013-09-18
SINO MAGNETICS TECH
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  • Claims
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Problems solved by technology

[0010] The present invention mainly solves the problem of grain growth in the sintering process of current sintered NdFeB. By applying hot isostatic pressing to reduce the sintering temperature, it not only maintains high density, but also obtains fine grain size, thereby improving the overall performance of the magnet.
[0011] The current sintering furnace can only be vacuumed but not pressurized, or can only be pressurized but not evacuated. This invention applies a new type of vacuum pressure sintering furnace developed by the latest cooperation, which solves the problem that both vacuum and pressure cannot be realized during the sintering process.

Method used

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  • Method for preparing high-performance sintered Nd-Fe-B magnet
  • Method for preparing high-performance sintered Nd-Fe-B magnet

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Embodiment 1

[0018] The selected magnet composition is Nd 13.5 Dy 0.5 Fe 79.97 B 6.03 , the alloy is smelted in a vacuum melting furnace with a vacuum degree of 10 -3 Pa, the alloy is cast using the quick-setting casting technology, and the thickness of the SC sheet is about 0.25~0.35mm. It is made into powder by hydrogen breaking and jet milling. After the powder is loosely packed, magnetic field orientation and pressing are carried out. The loose packing density is about 1.5g / cm 3 , the orientation field is greater than 1.5T. Next is the sintering stage, which can be sintered in two ways: one is the current sintering method, first vacuumize, and then continue to vacuumize, exhaust and heat up. Argon air cooling, magnet number set to 1 #The other is the sintering method of the present invention, first vacuumize, then continue to vacuumize and exhaust and heat up stage, after the exhaust finishes, stop vacuumizing before reaching or reaching the sintering temperature soon, pass into...

Embodiment 2

[0022] The selected magnet composition is Nd 13.5 Dy 0.5 Fe 79.97 B 6.03 , the alloy is smelted in a vacuum melting furnace with a vacuum degree of 10 -3 Pa, the alloy is cast using the quick-setting casting technology, and the thickness of the SC sheet is about 0.25~0.35mm. It is made into powder by hydrogen breaking and jet milling. After the powder is loosely packed, magnetic field orientation and pressing are carried out. The loose packing density is about 1.5g / cm 3 , the orientation field is greater than 1.5T. Next is the sintering stage, which is divided into two ways: one is to vacuumize first, and then continue to vacuumize, exhaust and heat up. Pure Ar gas is pressurized, the pressure is 10Mpa, sintering is carried out at a sintering temperature of 1080°C, and the temperature is kept for 3 hours. The next step is to continue vacuuming, exhausting and heating up. After the degassing is over, the vacuuming is stopped before reaching the sintering temperature, and...

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Abstract

The invention belongs to the field of rare-earth permanent magnetic materials and particularly provides a method for preparing high-density and fine-grain sintered Nd-Fe-B. The production method comprises the following steps: smelting and casting master alloy to make a rapid hardening thin band, grinding powder by hydrogen pulverizing gas flow, sintering and densifying under hot isostatic pressure after oriented molding, and finally carrying out tempering treatment to obtain a product. In the invention, through the application of gas pressure which is not lower than 0.5MPa in the sintering process, not only is the density of the magnet increased, the sintering temperature and the sintering time can also be lowered and shortened; and as a result, grains are obviously refined, and the distribution of Nd-rich phases among the grains is more uniform, so that the remanence and the coercivity of the magnet are improved, and the comprehensive performance is obviously improved.

Description

technical field [0001] The invention belongs to the field of rare earth permanent magnet materials, in particular to a preparation method of a high-density fine-grain sintered NdFeB magnet. Background technique [0002] Since the invention of sintered NdFeB permanent magnet material in 1983, it has attracted the attention of the world for its extremely high theoretical magnetic energy product. Although the preparation technology of this material is relatively mature and the industrial production has been realized for more than 20 years, there are still Some key technologies need to be broken through, and there is still a certain gap between my country's production technology and foreign countries. Before 2003, the main goal of the research on sintered NdFeB permanent magnet materials was to increase its magnetic energy product, but after 2003, it mainly focused on improving the coercive force and working temperature of the material. Therefore, the development of NdFeB magnet...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F1/057B22F9/04B22F3/16
Inventor 高学绪李明明包小倩孙绪新董清飞
Owner SINO MAGNETICS TECH
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