Production technology of Nd-Fe-B (neodymium-iron-boron) permanent-magnet material and corresponding jet-milling crusher

Abstract

The invention relates to a production technology of an Nd-Fe-B (neodymium-iron-boron) permanent-magnet material and a corresponding jet-milling crusher. The technology sequentially comprises steps as follows: mixing, smelting, hydrogen decrepitation, jet-milling, shaping and sintering, wherein smelted cast sheets become particles in the range of 45-355 mu m due to the hydrogen decrepitation technology. The technology is characterized in that the particles of overlarge sizes are sieved and separated out by the aid of a screen of 60-80 meshes firstly during blanking in the jet-milling step, and then the particles enter a milling chamber. According to the production technology and the corresponding jet-milling crusher, the particles of ideal sizes are separated by the aid of a sieving structure, the milling speed is increased, and liquid-phase sintering is facilitated.

Description

technical field [0001] The invention relates to the production field of NdFeB materials, in particular to a production process of NdFeB permanent magnet materials and a corresponding jet mill crusher. Background technique [0002] Nd-Fe-B alloy (Nd-Fe-B permanent magnet) is the most commonly used rare earth permanent magnet material, and it is also the best comprehensive magnetic material. The production of Nd-Fe-B materials mostly adopts the sintering method. Before sintering, it needs Grind the prepared powder into a fine powder and then shape it. In the process of turning the powder into a fine powder, two processes of hydrogen crushing and jet mill are often required. In the jet mill process, it must be used Jet mill. [0003] The crushing mechanism mainly applicable to the jet mill determines its wide application range and high fineness of the finished product. Typical materials include: superhard diamond, silicon carbide, metal powder, etc. High-purity requirements: c...

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Problems solved by technology

[0007] In the process of processing magnetic materials, a jet mill is also used to crush to obtain fine particles. Now based on the hydrogen crushing process, the Nd-rich phase in the magnetic material is first hydrogenated to cause intergranular fracture, and then the Nd2Fe14B1 phase causes grain boundary fracture. , the hydrogen breaking process can turn the cast sheet into particles in the range of 45-355 μm, most of which are around 125 μm. At this time, the coarser particles need multiple hydrogen absorption / hydrogen pumping cycles to achieve the ideal particle size, but this This method has the following disadvantages: the internal structure of the crystal will be destroyed; the abrasive speed is slow, the oxygen content of the powder will be high; the powder composition and particle shape are uneven; it is not conducive to liquid phase sintering; the molding orientation is not saturated; Unstable blank aging requirements

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