A method and device for preparing r-t-b rare earth permanent magnets

Abstract

The invention discloses a method for preparing an R-T-B rare earth permanent magnet. The method comprises the following steps: a) preparing an R<L>uR<H>vFe100-u-v-w-zBwMz rare earth alloy serving as a diffusion source, wherein R<L> represents at least one element of Pr and Nd, R<H> represents at least one element of Dy, Tb and Ho, M represents at least one element of Co, Nb, Cu, Al, Ga, Zr and Ti, and u, v, w and z satisfy the following relations: u is greater than or equal to 0 and smaller than or equal to 10, v is greater than or equal to 35 and smaller than or equal to 70, w is greater than or equal to 0.5 and smaller than or equal to 5, and z is greater than or equal to 0 and smaller than or equal to 5; b, smashing the rare earth alloy to form alloy powder; c), putting the alloy powder together with an R-T-B magnet in a rotary diffusion device for heat diffusion; and d) carrying out aging treatment. The method has the beneficial effect that efficient and low-cost production of an R-T-B rare earth permanent magnet material with high coercive force and low heavy rare earth content is realized.

Description

technical field [0001] The invention belongs to the technical field of rare earth permanent magnet materials, and in particular relates to a method and a device for preparing R-T-B rare earth permanent magnets. Background technique [0002] R-T-B rare earth permanent magnet materials have high remanence, coercive force and large magnetic energy product, and have been widely used in modern industry and electronic technology, such as electronic computers, automatic control systems, motors and generators, nuclear magnetic resonance imagers, Audio devices, material sorting devices, communication equipment and many other fields. With the development of new application fields and harsh and changeable application conditions, the demand for products with high coercive force is increasing. Coercivity is one of the main characteristics of permanent magnet materials, and improving coercivity has always been an important topic in the research and theoretical research of rare earth perm...

AI Technical Summary

Problems solved by technology

The coating method needs to arrange the processed R-T-B magnets before coating, which requires more workers to place the magnets, increasing production efficiency and cost

Vapor deposition needs to place the R-T-B magnet in a dysprosium box with supporting parts to evaporate dysprosium. The magnet cannot be in contact with the dysprosium or dysprosium alloy of the diffusion source. There cannot be mutual obstruction or contact between the R-T-B magnets, because pure dysprosium or simple dysprosium alloy (such as dysprosium iron, dysprosium aluminum alloy), softening or melting occurs at about 900 °C, which will lead to uneven penetration of dysprosium, and the products will stick to each other, resulting in unqualified products, and even the support will stick to dysprosium or dysprosium alloy.

As a result, the qualified rate of products is very low. On the other hand, more operators are required to place magnets or handle dysprosium plates and supports that are adhered after diffusion, and provide dysprosium or dysprosium alloys and their supports as diffusion sources. It needs to occupy a lot of space, and a certain distance needs to be kept between the magnets, which will greatly affect the charging capacity, and the lower charging capacity will lead to economic infeasibility

[0009] From the perspective of product positioning, for some R-T-B magnets with smaller specifications, such as magnets with a weight of less than 10g, especially magnets with a weight of less than 1g, the production cost due to labor, efficiency, and furnace loading is caused by the above-mentioned coating and evaporation methods. will be higher

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