Sintering method for neodymium-iron-boron magnet

Abstract

The invention provides a sintering method for a neodymium-iron-boron magnet. The method comprises the following steps: firstly, carrying out continuous warming or stepped warming on a green neodymium-iron-boron magnet body to reach a sintering temperature under a vacuum or protective gas condition, and obtaining a neodymium-iron-boron magnet intermediate; and carrying out constant-temperature firing on the neodymium-iron-boron magnet intermediate obtained in the previous step under a hydrogen condition, and obtaining a neodymium-iron-boron magnet blank. In a plurality of steps for preparing the neodymium-iron-boron magnet, hydrogen is filled into a system at a specific high-temperature sintering stage in the sintering process from the sintering method, so that a neodymium-rich phase in the blank material is uniform in distribution; a rare-earth phase is prevented from being consumed; a rare-earth phase oxide is avoided; rare earth does not need to add when a formula is designed; the cost is saved; the coercivity of a product is also improved; and the sintering method has very important significance for development of a neodymium-iron-boron magnet product.

Description

technical field [0001] The invention belongs to the technical field of magnet preparation, and in particular relates to a sintering method of an NdFeB magnet. Background technique [0002] Whether in industrial production or in daily life, hard magnets are permanent magnets, magnets that can maintain their magnetism for a long time, are not easy to lose their magnetization, and are not easy to be magnetized. They are also one of the most commonly used strong materials. Hard magnets can be divided into natural magnets and artificial magnets. Artificial magnets mean that by synthesizing alloys of different materials, the same effect as natural magnets (magnets) can be achieved, and the magnetic force can also be improved. Artificial magnets appeared as early as the 18th century, but the process of manufacturing stronger magnetic materials was very slow. It was not until the manufacture of AlNiCo magnets (AlNiCo) in the 1930s that the large-scale application of magnets became p...

AI Technical Summary

Problems solved by technology

[0005] However, in recent years, with the wide application of NdFeB magnets, the production of NdFeB magnets requiring higher stability and lower cost has been promoted. However, rare earths are easily oxidized during the sintering process of sintered NdFeB permanent magnets. , resulting in the need to add more rare earths when designing the formula, or the unsatisfactory magnetic properties, especially the coercive force after sintering, have gradually become obstacles to its further development.

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