Grain boundary diffusion multiphase structure alloy, preparation method thereof and method for preparing high-performance neodymium-iron-boron magnet

Abstract

The invention provides a multiphase structure alloy for grain boundary diffusion. The multiphase structure alloy has a general formula as shown in a formula (I): R < 1 > aR < 2 > bM < 1 > cM < 2 > dM < 3 > e (I). According to the method for preparing the high-performance neodymium-iron-boron magnet through the grain boundary diffusion multiphase structure alloy, by means of optimal design of a diffusion source and a diffusion technology, the diffusion driving force of heavy rare earth in the diffusion process is regulated and controlled, the diffusion depth of the heavy rare earth is improved, the use amount of the heavy rare earth is reduced, the diffusion effect of the heavy rare earth is guaranteed, and the diffusion efficiency of the magnet is improved; the method has important significance on the development of the sintered NdFeB permanent magnet material industry. The alloy diffusion source of the multi-component and multi-phase structure is prepared by optimizing the alloy phase structure through multi-stage annealing, and then the high-performance neodymium-iron-boron magnet is obtained through diffusion heat treatment. The heavy rare earth diffusion driving force is regulated and controlled, heavy rare earth surface accumulation is reduced, the diffusion effect depth is increased, and the method is suitable for preparing high-performance multi-element alloy diffusion magnets in batches.

Description

technical field [0001] The invention belongs to the technical field of magnet preparation, relates to a multiphase structure alloy used for grain boundary diffusion and a preparation method thereof, a preparation method of a neodymium iron boron magnet, and in particular relates to a grain boundary diffusion multiphase structure alloy and preparation thereof A method, a method for preparing a high-performance NdFeB magnet by grain boundary diffusion multiphase structure alloy. Background technique [0002] High coercivity and high comprehensive performance sintered NdFeB magnets have the characteristics of strong anti-demagnetization ability, high temperature stability and low coercivity temperature coefficient. The speed of promotion and the scope of application are rapidly expanding, such as high-end fields such as new energy vehicles, inverter compressors, industrial robots, and rail transit. The coercivity of sintered NdFeB is related to the anisotropy field. The larger...

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Problems solved by technology

However, as far as the current grain boundary diffusion technology is concerned, there are problems that need to be solved urgently: on the one hand, the diffusion distance of heavy rare earth elements inside the magnet is very limited, and if the problem of too small diffusion distance of heavy rare earth elements cannot be solved, it will greatly limit The scope of application of this technology, whether the heavy rare earth can penetrate from the surface of the magnet into the interior, how far it can penetrate, and how well the penetration effect can directly determine the practicality of the technology; The formed heavy rare earth magnetically hardened shell is too thick (backscattering observations are usually close to the micron level), and the theoretically calculated magnetic hardened shell of 14 nanometers on the surface has been saturated, and the accumulation characteristics of heavy rare earth on the surface of the magnet hinder its further efficient use. ; At the same time, it often happens that the designed diffusion source is incompatible with the composition formula of the magnet matrix, and the consistency and stability of the diffusion effect are poor, which limits the application market of the diffusion magnet

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