Rare earth permanent magnet and preparation method thereof

Abstract

The invention relates to a preparation method of a rare earth permanent magnet. The preparation method comprises the following steps of (1) providing first magnetic powder and second magnetic powder separately, wherein the first magnetic powder is alloy magnetic powder B; the second magnetic powder is alloy magnetic powder R or mixed magnetic powder A; the mixed magnetic powder A is obtained by mixing of the alloy magnetic powder B and alloy powder; the coercivity of a magnet prepared from the second magnetic powder is higher than that of a magnet prepared from the first magnetic powder; (2) putting the first magnetic powder in the middle part of a die, putting the second magnetic powder into the upper part and the lower part of the die, and performing hot press molding to obtain a hot pressed magnet; and (3) performing thermal deformation molding on the hot pressed magnet to obtain the rare earth permanent magnet, wherein the rare earth permanent magnet comprises a middle layer formedby the first magnetic powder and an upper layer and a lower layer formed by the second magnetic powder; and in addition, a transition layer is formed between the middle layer and the upper layer, andbetween the middle layer and the lower layer separately. The invention also relates to a rare earth permanent magnet body.

Description

technical field [0001] The invention belongs to the technical field of rare earth permanent magnet materials, and relates to a rare earth permanent magnet and a preparation method thereof. Background technique [0002] In recent years, rare earth permanent magnets have been used in various industries, especially in clean energy such as wind power generation, energy-saving appliances, and electric vehicles. The output and consumption of rare earth permanent magnets are increasing year by year. With the expansion of the application range, rare earth permanent magnets are required to have high performance and high temperature resistance, and at the same time, rare earth permanent magnets are required to be used in relatively high temperature environments. [0003] The most common way to improve the high temperature resistance of rare earth permanent magnets is to increase the coercive force of the magnets. There are many ways to increase the coercive force of the magnet. For e...

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Problems solved by technology

However, this method only diffuses a small amount of heavy rare earth elements, and it is difficult to diffuse more heavy rare earth elements into the interior of the magnet

In other words, this method is limited by the thickness of the magnet. When the thickness of the magnet is larger, the proportion of heavy rare earth elements diffused into the magnet decreases, and the diffusion amount of heavy rare earth elements is not easy to control

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