Preparation method for rare earth permanent magnet material

Abstract

The invention relates to a preparation method for a rare earth permanent magnet material. The preparation method comprises the steps of weighing powder of three kinds of raw materials of H, M and Q according to atomic percentage contents in a general formula of H<100-x-y>M<x>Q<y>, and performing mixing and screening processing in nitrogen or other oxygen-less environment to obtain composite powder; next, performing mechanical processing on a sintered NdFeB magnet to obtain specific shapes and dimensions, and performing surface cleaning and drying to obtain a to-be-processed NdFeB magnet; next, enabling the composite powder to be attached to the surface of the to-be-processed NdFeB magnet through static in an oxygen-less environment; and performing vacuum heat treatment and tempering treatment in sequence to obtain the rare earth permanent magnet material. By adoption of the method, high efficiency, high binding force between heavy rare earth element attachment and the base magnet, and convenience in residual powder recycling are realized; and the coercivity of the prepared NdFeB magnet can be improved by 4,000-14,000Oe, the residual magnetism is only reduced by 1-2%, and the heavy rare earth usage amount can be saved by 30% compared with that of the equivalent-performance magnet.

Description

technical field [0001] The invention relates to a preparation method of a rare earth permanent magnet material, in particular to a magnet that adopts electrostatic adhesion of one or more compounds rich in heavy rare earth and pure metal powder on the surface of a sintered NdFeB magnet, and is treated at high temperature and improved by low temperature aging. The performance method belongs to the technical field of rare earth permanent magnet materials. Background technique [0002] NdFeB permanent magnet materials are widely used in hybrid vehicles, wind power generation, energy-saving motors, and inverter air conditioners. These fields require magnets to work at high temperatures for a long time, and rare earth permanent magnets should have higher coercivity Hcj. An effective way to increase the coercive force Hcj of NdFeB sintered magnets is to replace the main phase Nd of the magnet with heavy rare earth elements such as dysprosium (Dy) and terbium (Tb). 2 Fe 14 Nd in ...

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Problems solved by technology

However, in these studies, there are still some problems to be solved: (1) The method of attaching Dy / Tb to the surface of NdFeB sintered magnets by sputtering has low productivity, high process cost, and defects such as melting pits are prone to occur. During the process, a large number of rare earth metals are scattered in the heating furnace chamber, causing unnecessary waste of heavy rare earth metals; (2) the method of vapor phase precipitation has the disadvantages of low utilization rate of heavy rare earth elements and high processing temperature; (3) coating on the surface Rare earth oxide or fluoride coated with heating and diffusion has the problem of limited coercivity improvement; (4) In addition, because Dy / Tb is expensive, the most effective use of Dy / Tb resources is also a key issue in this type of technology

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