Preparation method of neodymium-iron-boron magnet

Abstract

The invention provides a preparation method of a neodymium-iron-boron magnet, relating to the field of production of the neodymium-iron-boron magnet. By virtue of processes of formula optimization, oriented molding, magnet oxygen content control and the like, the invention provides a preparation method of a high-performance sintering neodymium-iron-boron magnet, which solves the problem of batch production of high-performance sintering neodymium-iron-boron products. The preparation method comprises the following steps: weighing 30.0-31.5% of praseodymium and neodymium, 0.9-1.0% of boron, 0-2.0% of terbium, 0.03-0.60% of aluminum, 0.05-0.25% of copper, 0.3-1.5% of cobalt, 0-0.2% of zirconium, 0-0.3% of niobium, 0.05-0.3% of gallium and 62.35-68.67% of iron, and melting and casting to obtain a cast sheet; putting the cast sheet into a rotary hydrogen smashing furnace for processing to obtain coarse powder; adding a lubricating agent into the coarse powder for grinding to obtain fine powder; adding a lubricating agent and an antioxidant into the fine powder, and mixing the powder with a double-cone powder mixer to obtain powder; and making a mold to obtain a billet product, and sintering and cooling to obtain a finished product.

Description

technical field [0001] The invention relates to the field of NdFeB magnet production, in particular to a preparation method of NdFeB magnets. Background technique [0002] NdFeB magnets have excellent magnetic properties. Usually, their production processes include batching, smelting, hydrogen crushing, powder making, orientation pressing, isostatic pressing, sintering, tempering, post-processing, surface treatment, etc. [0003] The theoretical magnetic energy product of sintered NdFeB magnet is 64MGOe, but limited by the main phase ratio, relative density, orientation degree and other factors of the actual magnet, the positive limit of magnetic energy in the test is about 59MGOe. In a sense, high magnetic energy product NdFeB The development potential of permanent magnet materials is very limited. However, from the perspective of production and application, there are not many companies that can stably mass-produce high-energy-product NdFeB permanent magnet materials N54, ...

AI Technical Summary

Problems solved by technology

[0004] At present, in the production of high-performance sintered NdFeB, such as N54, 52M, 50H and other high-remanence and high-energy product grades, in order to increase the Br of the magnet, it is necessary to increase the volume fraction of the main phase as much as possible, so the total amount of rare earth in the formula is relatively low. If the production If the process control is not good, the oxygen content of the magnet will be high, and the magnetic performance of the magnet will drop rapidly.