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Preparation method of sintered rare earth permanent magnets and rotary diffusion and hydrogen decrepition integrated furnace

A rare earth permanent magnet, permanent magnet technology, applied in the direction of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problems of uneven diffusion, seal damage, easy deformation and adhesion, etc. Coercivity, the effect of saving heavy rare earths

Active Publication Date: 2018-11-30
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Both of these two schemes are carried out on the surface after sintering, and both have these common defects: 1) Small and large number of workpieces need to be placed one by one, and the efficiency is low
2) It is prone to deformation and adhesion during the diffusion process, which affects the dimensional accuracy
3) Due to the limitation of penetration and diffusion distance, thicker products cannot be made
4) Due to the thickness error of coating or sputtering, the dispersion of coercive force increases
Because there is a little angle between the furnace and the horizontal line, the diffusion, dehydrogenation and hydrogen absorption are not uniform
The discharge pipe is at the bottom. In order to prevent the powder from flowing out, a baffle should be added, and this baffle must be removed before discharging. This process will inevitably cause damage to the seal.
[0010] Structure 3: Similar to a sintering furnace or a continuous sintering furnace, the furnace material is installed in the sintering boat, and the relative position of the material and the boat is fixed during the whole process. Since the addition of secondary phase is less than 5%, it will inevitably cause uneven diffusion
[0011] The above three are therefore not suitable for the needs of diffusion

Method used

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  • Preparation method of sintered rare earth permanent magnets and rotary diffusion and hydrogen decrepition integrated furnace
  • Preparation method of sintered rare earth permanent magnets and rotary diffusion and hydrogen decrepition integrated furnace
  • Preparation method of sintered rare earth permanent magnets and rotary diffusion and hydrogen decrepition integrated furnace

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preparation example Construction

[0045] A method for preparing sintered rare earth permanent magnets, based on RFe 14 B is the main phase, R TM The alloy is a secondary phase, and its preparation method is as follows:

[0046] Preparation of master alloy and secondary phase alloy:

[0047] Total rare earth RFe 14 Near B, that is, R accounts for 27-30% by weight, B content is 1.1-1.25%, and the rest is Fe. Perform rapid smelting to obtain a master alloy of 0.1 to 0.5 mm. R can be a single element such as Nd, Pr, Dy, Tb, Ce, La, Gd, and Ho, or a combination of several elements, preferably light rare earth. You can also replace part of Fe with Go.

[0048] R is produced by smelting high content of rare earth TM The alloy is a secondary phase, and the rare earth content accounts for 50% to 100%. It can be one or more combinations of Nd, Pr, Dy, Tb, Ho, and Gd. The alloy object may be one or a combination of Fe, Cu, Al, and Ga.

[0049] The secondary phase alloy is made into 0.1-5mm particles or quick-setting flakes, ...

Embodiment 1

47.35

0.97

[0074] According to the formula of Nd, Pb, Co, B, Fe, vacuum smelting, the main phase alloy sheet with a thickness of 0.3~0.5mm is spun quickly.

[0075] In order to ensure performance, it is required that there is no oxide layer on the alloy sheet, and the discharge of the quick-setting furnace is required to be in a sealed barrel. When adding the diffusive hydrogen crushing furnace, it must be strictly protected from contact with air.

[0076] For the preparation of secondary phase alloys, Dy metal accounts for 78% of the total, and the rest is Fe (10%), Al (5%), Cu (5%), Ge (2%), smelted under vacuum, and can be quick-setting flakes , It can also be an alloy block, which is machined into small blocks less than 4mm.

[0077] The master alloy and 2.5% of the secondary phase alloy particles are loaded into a sealed barrel under a sealed condition, and then docked with the feeder. Under the combined action of the vibrating feeder and the spiral in the furnace, all the mater...

Embodiment 2

[0081]

[0082] Master alloy: smelt the alloy containing Ce up to 25%, Pr+Nd=4.5% and vacuum smelt to obtain a fast-solidified thin strip of 0.3mm.

[0083] The secondary phase alloy, Nd+Pr metal content is 80%, the rest is Cu(5), Al(5), Fe(10). The alloy ingot is melted in vacuum and crushed to 4mm mechanically.

[0084] The master alloy ribbon and 2.5% of the main phase alloy (in the form of lumps) are loaded into the diffusive hydrogen crushing furnace at the same time, then the temperature is raised to 650~850℃, the hydrogen pressure (relative pressure) is maintained at 0.05~0.096MPa, and the diffusion treatment is carried out 5 hours; turn off the hydrogen source, dehydrogenate for 3 hours, cool to room temperature and then release, jet mill to an average particle size of 3 microns, magnetic field molding under 500ppm low oxygen environment, conventional vacuum sintering and tempering treatment to obtain N30 performance.

[0085]

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Abstract

The invention belongs to the technical field of permanent magnet materials, and particularly relates to a preparation method of sintered rare earth permanent magnets and a rotary diffusion and hydrogen decrepition integrated furnace. In the method, a secondary phase is infiltrated into a mother alloy in a diffusion manner during hydrogen decrepition, that is, the secondary phase alloy diffuses between main phases, so as to uniformly distribute the (heavy) rare earth alloy phase between the main phases. Subsequently, jet milling pulverization, magnetic field molding and sintering are carried out. Since the thickness of the mother alloy flake is 0.2 to 0.5 mm, diffusion is very easy. Therefore, a high-remanence and high-coercivity product can be obtained at a lower cost. Or, Ce and La, the amount of which accounts for 70% or more of the total amount of rare earth, are added into the main phase, and then Pr and Nd alloys are diffused to serve as the secondary phase, so as to obtain a magnet with medium performance and low cost.

Description

Technical field [0001] The invention belongs to the technical field of permanent magnet materials, and in particular relates to a preparation method of sintered rare earth permanent magnets and a rotary integrated hydrogen diffusion furnace. Background technique [0002] The manufacturing method of high-coercivity sintered NdFeB permanent magnets. The traditional technology is to increase the coercivity by adding heavy rare earth materials during the smelting process, but most of the Dy, Ho or Tb will enter during the crystallization of the smelting process. Only a small part of the main phase is distributed in the grain boundary, which leads to a decrease in remanence and insufficient coercivity. [0003] Therefore, people have improved on this and improved the utilization of rare earth raw materials through other methods: the first method is the dual alloy method; it is close to Nd 2 Fe 14 B is the main phase and the mixed sub-phase, because the sub-phase is technically difficult...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F41/02B22F9/02
CPCB22F9/023H01F1/0577H01F41/0253
Inventor 董开
Owner 董开