A kind of preparation method of the permanent magnet material of low heavy rare earth, high coercive force

Abstract

The invention provides a preparation method for a permanent magnet material with low content of heavy rare earth and high coercivity. The preparation method comprises the steps of performing mixing and thermal treatment on rare earth-iron-boron alloy powder and heavy rare earth metal or alloy powder while constantly stirring to enable heavy rare earth metal atoms to be dispersed to a surface layer of the rare earth-iron-boron alloy powder to obtain a mixture; putting the mixture into a magnetic field of greater than 1.5T and forming a pressing blank through orientating and pressing; and performing high-temperature sintering and tempering treatment on the pressing blank to prepare the sintered rare earth-iron-boron permanent magnet material. The sintered rare earth-iron-boron permanent magnet material prepared by the invention has the characteristics of low content of heavy rare earth and high coercivity.

Description

technical field [0001] The invention belongs to the field of magnetic materials, and in particular relates to a preparation method of a permanent magnet material with low heavy rare earth and high coercive force. Background technique [0002] Permanent magnet material, also known as "hard magnetic material", refers to a functional material that is not easy to demagnetize after magnetization saturation and can retain magnetism for a long time. It has been widely used in aerospace, mechanical electronics, instrumentation, household appliances and many other fields. It has become the material basis for the development of machinery, power, electronic information and other industries. Among them, the sintered rare earth-iron-boron permanent magnet material is a typical representative of rare earth permanent magnet materials and is currently the most widely used permanent magnet material. [0003] Although rare earth-iron-boron permanent magnet materials have been widely used, th...

AI Technical Summary

Problems solved by technology

However, this method also has obvious deficiencies: 1. when the doped powder is a micron powder, because the powder particles are relatively coarse (similar to the rare earth-iron-boron alloy powder particle size) and the doping amount is small (less than 5% by mass fraction) , the doped heavy rare earth elements are difficult to distribute evenly along the grain boundary and grain surface, the heavy rare earth content in the grain boundary and grain surface near the doped powder is high, and the grain boundary and grain surface far away from the doped powder The content of heavy rare earth in the medium is low, which leads to the uneven performance of the whole magnet, which affects the use of the magnet; ②When the doped powder is nano powder, it is difficult to prepare and store the nano powder, plus the agglomeration effect of the nano powder and the combination with rare earth - The difference in particle size of iron-boron alloy powder makes it difficult to mix evenly with the micron powder of rare earth-iron-boron alloy, resulting in uneven distribution of heavy rare earth elements in the magnet, which directly affects the uniformity of magnet performance and use

[0006] Dy film coating process by magnetron sputtering on the powder surface [ZL201110242847.7] effectively overcomes the shortcomings and deficiencies of the direct addition and grain boundary doping process while improving the coercive force of the magnet, but the magnetron sputtering on the surface of micron powder is difficult, High cost, not suitable for mass industrial production

Images