Method for preparing high-performance sintered neodymium-iron-boron magnet based on grain boundary addition

Abstract

The invention discloses a method for preparing a high-performance sintered neodymium-iron-boron magnet based on grain boundary addition. The method comprises the steps that firstly, main alloy is prepared according to the composition of atomic ratio Nd: Fe: B=2: 14: 1; main alloy and two kinds of grain boundary phase micron powder of a heavy rare earth compound and a high melting point element areprepared by the method of gas atomization or rapid solidification casting, hydrogen explosion and jet milling; three kinds of powder are uniformly mixed by compositely adding the micron-level heavy rare earth compound and a high melting point element regulating grain boundary structure; a flake is acquired through magnetic field molding, cold isostatic pressing and the like; and finally dischargeplasma sintering (SPS) and secondary tempering are carried out to acquire the high-performance sintered neodymium-iron-boron magnet with the maximum magnetic energy product greater than or equal to 45 MGOE and intrinsic coercivity greater than or equal to 25KO. Compared with the prior art, the method provided by the invention has the advantages of high processing efficiency, low production cost and good consistency of magnetic properties, is easy to realize commercial applications, can well meet customer needs, and is very suitable for preparing the high-performance sintered neodymium-iron-boron magnet.

Description

technical field

[0001] The invention relates to a preparation method of a high-performance sintered NdFeB magnet based on grain boundary addition, and belongs to the technical field of rare earth permanent magnet material preparation. Background technique

[0002] Since its invention in 1983, sintered NdFeB magnet has developed into an indispensable key material in high-tech fields such as information, energy, transportation and national defense because of its advantages such as high magnetic energy product, high coercive force and high cost performance. As the world vigorously advocates energy saving, emission reduction and green energy, the new energy industry represented by electric vehicles, wind power, and energy-saving home appliances has developed rapidly. These fields require sintered NdFeB magnets to have a high magnetic energy product BHmax to provide Sufficiently large magnetic energy storage and high enough intrinsic coercivity (Hcj≥30KOe) to ensure normal operat...

Examples

Embodiment 1

[0054] A method for preparing a high-performance sintered NdFeB magnet based on grain boundary addition, the process is as follows:

[0055] A. Prepare the main alloy: select raw materials with a purity of 99.5% or more, and remove the oxide skin on the surface of the raw materials, according to the alloy composition (PrNd) 30.5 [Fe 0.9 (CuAlZn) 0.1 ] 68.5 B 1 (wt.%), raw materials were weighed with an electronic balance.

[0056] B. Preparation of the main alloy powder: the prepared main alloy is casted quickly to obtain flakes, the melting temperature is 1450°C, and the line speed of the water-cooled copper roll is 2.0m / s; then hydrogen explosion is obtained to obtain coarse powder, and the hydrogen absorption pressure is 0.1 MPa, the dehydrogenation temperature is 590°C, and the dehydrogenation time is 2h; finally, the magnetic powder with an average particle size of 3.2um is obtained by jet milling, and the speed of the classification wheel is 4000r / s.

[0057] C. Pre...

Embodiment 2

[0071] A method for preparing a high-performance sintered NdFeB magnet based on grain boundary addition, the process is as follows:

[0072] A. Prepare the main alloy: select raw materials with a purity of 99.5% or more, and remove the oxide skin on the surface of the raw materials, according to the alloy composition (PrNd) 30.5 [Fe 0.92 (CuGaZn) 0.08 ] 68.2 B 1.03 (wt.%), raw materials were weighed with an electronic balance.

[0073] B. Preparation of the main alloy powder: the prepared main alloy is obtained by quick-setting casting, the melting temperature is 1440°C, and the line speed of the water-cooled copper roll is 2.5m / s; followed by hydrogen explosion to obtain coarse powder, and the hydrogen absorption pressure is 0.1 MPa, the dehydrogenation temperature is 580°C, and the dehydrogenation time is 2.5h; finally, the jet mill obtains magnetic powder with an average particle size of 3.5um, and the speed of the classification wheel is 3500r / s.

[0074] C. Preparati...

Embodiment 3

[0086] A method for preparing a high-performance sintered NdFeB magnet based on grain boundary addition, the process is as follows:

[0087] A. Prepare the main alloy: select raw materials with a purity of 99.5% or more, and remove the oxide skin on the surface of the raw materials, according to the alloy composition (PrNd) 30 [Fe 0.92 (AlGaSn) 0.08 ] 69 B 1 (wt.%), raw materials were weighed with an electronic balance.

[0088] B. Preparation of the main alloy powder: the prepared main alloy is obtained by quick-setting casting, the melting temperature is 1440°C, and the line speed of the water-cooled copper roll is 2.5m / s; followed by hydrogen explosion to obtain coarse powder, and the hydrogen absorption pressure is 0.1 MPa, the dehydrogenation temperature is 570°C, and the dehydrogenation time is 4h; finally, the magnetic powder with an average particle size of 4um is obtained by jet milling, and the speed of the classification wheel is 3200r / s.

[0089] C. Preparatio...

technical field

[0001] The invention relates to a preparation method of a high-performance sintered NdFeB magnet based on grain boundary addition, and belongs to the technical field of rare earth permanent magnet material preparation. Background technique

[0002] Since its invention in 1983, sintered NdFeB magnet has developed into an indispensable key material in high-tech fields such as information, energy, transportation and national defense because of its advantages such as high magnetic energy product, high coercive force and high cost performance. As the world vigorously advocates energy saving, emission reduction and green energy, the new energy industry represented by electric vehicles, wind power, and energy-saving home appliances has developed rapidly. These fields require sintered NdFeB magnets to have a high magnetic energy product BHmax to provide Sufficiently large magnetic energy storage and high enough intrinsic coercivity (Hcj≥30KOe) to ensure normal operat...

Examples

Embodiment 1

[0054] A method for preparing a high-performance sintered NdFeB magnet based on grain boundary addition, the process is as follows:

[0055] A. Prepare the main alloy: select raw materials with a purity of 99.5% or more, and remove the oxide skin on the surface of the raw materials, according to the alloy composition (PrNd) 30.5 [Fe 0.9 (CuAlZn) 0.1 ] 68.5 B 1 (wt.%), raw materials were weighed with an electronic balance.

[0056] B. Preparation of the main alloy powder: the prepared main alloy is casted quickly to obtain flakes, the melting temperature is 1450°C, and the line speed of the water-cooled copper roll is 2.0m / s; then hydrogen explosion is obtained to obtain coarse powder, and the hydrogen absorption pressure is 0.1 MPa, the dehydrogenation temperature is 590°C, and the dehydrogenation time is 2h; finally, the magnetic powder with an average particle size of 3.2um is obtained by jet milling, and the speed of the classification wheel is 4000r / s.

[0057] C. Pre...

Embodiment 2

[0071] A method for preparing a high-performance sintered NdFeB magnet based on grain boundary addition, the process is as follows:

[0072] A. Prepare the main alloy: select raw materials with a purity of 99.5% or more, and remove the oxide skin on the surface of the raw materials, according to the alloy composition (PrNd) 30.5 [Fe 0.92 (CuGaZn) 0.08 ] 68.2 B 1.03 (wt.%), raw materials were weighed with an electronic balance.

[0073] B. Preparation of the main alloy powder: the prepared main alloy is obtained by quick-setting casting, the melting temperature is 1440°C, and the line speed of the water-cooled copper roll is 2.5m / s; followed by hydrogen explosion to obtain coarse powder, and the hydrogen absorption pressure is 0.1 MPa, the dehydrogenation temperature is 580°C, and the dehydrogenation time is 2.5h; finally, the jet mill obtains magnetic powder with an average particle size of 3.5um, and the speed of the classification wheel is 3500r / s.

[0074] C. Preparati...

Embodiment 3

[0086] A method for preparing a high-performance sintered NdFeB magnet based on grain boundary addition, the process is as follows:

[0087] A. Prepare the main alloy: select raw materials with a purity of 99.5% or more, and remove the oxide skin on the surface of the raw materials, according to the alloy composition (PrNd) 30 [Fe 0.92 (AlGaSn) 0.08 ] 69 B 1 (wt.%), raw materials were weighed with an electronic balance.

[0088] B. Preparation of the main alloy powder: the prepared main alloy is obtained by quick-setting casting, the melting temperature is 1440°C, and the line speed of the water-cooled copper roll is 2.5m / s; followed by hydrogen explosion to obtain coarse powder, and the hydrogen absorption pressure is 0.1 MPa, the dehydrogenation temperature is 570°C, and the dehydrogenation time is 4h; finally, the magnetic powder with an average particle size of 4um is obtained by jet milling, and the speed of the classification wheel is 3200r / s.

[0089] C. Preparatio...

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