Preparation method of low-heavy-rare-earth and high-coercivity neodymium iron boron magnet

Abstract

The invention discloses a preparation method of a low-heavy-rare-earth and high-coercivity neodymium iron boron magnet. The preparation method comprises the steps of performing material mixing based on designed components, smelting, quick hardening and piece casting; performing hydrogen decrepitation, a disproportionation reaction and air flow grinding on a neodymium iron boron cast piece to obtain neodymium iron boron fine powder; adopting a thermal resistance evaporation deposition method, depositing heavy rare earth element particles or high smelting quality element particles on the neodymium iron boron fine powder; and performing orientation pressing and shaping, vacuum sintering and thermal treatment on the obtained neodymium iron boron fine powder to obtain the final neodymium iron boron magnet. By virtue of the preparation method, the magnet coercivity of the obtained magnet material can be obviously improved, the magnet crystal particle can be thinned, the dosage of the heavy rare earth elements can be lowered, and the magnet manufacturing cost is lowered.

Description

technical field [0001] The invention relates to a material powder processing technology, in particular to a preparation method of a low-weight rare earth high-coercivity neodymium-iron-boron magnet. Background technique [0002] NdFeB permanent magnet materials are the most concerned rare earth application industry in my country's rare earth industry. With the development of science and technology and technological progress, the demand for high-performance NdFeB permanent magnet materials is becoming more and more extensive. In order to improve the coercive force and high-temperature usability of NdFeB, the commonly used method is to add a small amount of heavy rare earth elements (such as Dy, Tb, etc.) or optimize the process to refine the magnet grains. [0003] At present, the methods to reduce the usage of heavy rare earth mainly include double alloy process and grain boundary diffusion heavy rare earth element process. The double alloy process is to smelt the main allo...

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Problems solved by technology

However, the disadvantage of the magnetron sputtering method is that the utilization rate of the material is less than 50%; the electron beam evaporation equipment is expensive, and the requirements for vacuum and evaporation temperature are high; although the material utilization rate of vacuum induction evaporation is close to 99%, the disadvantage is that it requires high vacuum. For high melting point metals, the temperature is too low, the evaporation rate is slow, and the thermal efficiency is low

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