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High-performance sintered neodymium-iron-boron magnet

A NdFeB high-performance technology, applied in the direction of magnetic objects, magnetic materials, inorganic materials, etc., can solve the problems of high cost and poor machinability, and achieve the effect of improving brittleness, stable performance and improving coercivity.

Inactive Publication Date: 2016-04-20
NINGBO HONGLEI MAGNETICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to improve the coercive force of sintered NdFeB, adding some trace elements to the grain boundary is a relatively common method, but most of these elements are rare earth oxides or pure rare earth powders. By adding these elements, the Nd-rich grain boundary is increased. Phase or magnetically hardened grain boundaries to achieve the purpose of increasing the coercive force, and at the same time the cost is high
At the same time, sintered NdFeB is a brittle material. People pay more and more attention to the machinability of sintered NdFeB. The sintered NdFeB prepared by the current process is generally brittle and has poor machinability.

Method used

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Experimental program
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Effect test

Embodiment 1

[0020] In this embodiment, the alloy composition is (PrNd)27.2Gd4.0Al0.8Cu0.2Co1.0B0.98Febal (content is weight percent, wt%), which is smelted in a vacuum induction casting furnace to prepare an alloy cast sheet of this composition. Then the alloy cast flakes are crushed into a coarse powder with an average particle size of 50 μm by hydrogen crushing, and then ultrafinely pulverized by a high-pressure water jet to grind the coarse powder into a fine powder with an average particle size of 3.3 μm. The micropowder is divided into two groups: the first group is the micropowder without adding titanium powder, which is mixed by a three-dimensional mixer, and the mixing time is 6 hours, and then sifted with a 200-mesh sifter; the second group is Add the micropowder of titanium powder, add the titanium powder that weight percent is 0.2wt% in micropowder, the average particle size of titanium powder is 15 μ m, carry out mixing by three-dimensional mixing machine, mixing time is 6 hour...

Embodiment 2

[0030] In this embodiment, the alloy composition is (PrNd)27.2Gd4.0Al0.8Cu0.2Co1.0B0.98Febal (content is weight percent, wt%), which is smelted in a vacuum induction casting furnace to prepare an alloy cast sheet of this composition. Then the alloy cast flakes are crushed into a coarse powder with an average particle size of 100 μm by hydrogen breaking, and then ultrafinely pulverized by a high-pressure water jet to grind the coarse powder into a fine powder with an average particle size of 2.7 μm. Add the titanium powder that weight percent is 0.2wt% to micropowder, the average particle size of titanium powder is 8 μ m, carry out mixing by three-dimensional mixing machine, mixing time is 6 hours, then use mesh number to be 200 mesh powder sieving machines to sieve powder . The micropowder is respectively pressed and formed in a closed press under the protection of nitrogen. The size of the green compact is a square of 57.5×30×48, and the oxygen content in the closed press is ...

Embodiment 3

[0032]In this embodiment, the alloy composition is (PrNd)27.2Gd4.0Al0.8Cu0.2Co1.0B0.98Febal (content is weight percent, wt%), which is smelted in a vacuum induction casting furnace to prepare an alloy cast sheet of this composition. Then the alloy cast flakes are crushed into a coarse powder with an average particle size of 200 μm by hydrogen crushing, and then ultrafinely pulverized by a high-pressure water jet to grind the coarse powder into a fine powder with an average particle size of 3.8 μm. Add titanium powder with a weight percentage of 0.2wt% in the micropowder, the average particle size of the titanium powder is 47 μm, mix the mixture through a three-dimensional mixer, the mixing time is 6 hours, and then sieve the powder with a 200-mesh sifter . The micropowder is respectively pressed and formed in a closed press under nitrogen protection. The size of the compact is 57.5×30×48 squares, and the oxygen content in the closed press is required to be lower than 970ppm. ...

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Abstract

The invention discloses a high-performance sintered neodymium-iron-boron magnet. The magnet is prepared from the balance of RxMyBzFe, wherein R is one or more out of La, Ce, Pr, Nd, Gd, Ho and Dy, a total mass fraction of R is x, M is one or more out of Co, Al, Cu, Nb, Zr and Ga, a total mass fraction of R is y, x is equal to 29 to 30 percent by weight, Y is equal to 0 to 2 percent by weight, and z is equal to 0.9 to 1.1 percent by weight; and the magnet is formed by smelting raw materials, casting the raw materials into sheets, preparing powder, molding the powder into a blank and sintering and forming, wherein in the powder preparation step, the raw materials is subjected to ultrafine grinding by utilizing high-pressure water in a jet flow manner to prepare alloy micro powder. The coercive force of the magnet is improved, and the brittleness of the magnet is also improved.

Description

technical field [0001] The invention relates to a permanent magnet, in particular to a high-performance sintered NdFeB magnet. Background technique [0002] NdFeB magnets are mainly intermetallic compounds composed of rare earth elements R, iron and boron. R is mainly neodymium or a combination of neodymium and other rare earth elements, and sometimes cobalt, aluminum, vanadium and other elements are used to replace part of iron. It is mainly divided into sintered NdFeB and bonded NdFeB. Bonded NdFeB is magnetic in all directions and is corrosion-resistant; and sintered NdFeB is easy to corrode, and the surface needs to be coated. Generally, there are galvanized, nickel, Environmental protection zinc, environmental protection nickel, nickel copper nickel, environmental protection nickel copper nickel, etc. Sintered NdFeB is generally divided into axial magnetization and radial magnetization, depending on the required working surface. [0003] NdFeB permanent magnet materi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F1/08B22F3/02B22F3/10
CPCB22F3/02B22F3/1017H01F1/0571H01F1/0575
Inventor 张宏芳
Owner NINGBO HONGLEI MAGNETICS