Preparation method of sintered Nd-Fe-B permanent magnet material

Abstract

A high-coercivity and high-corrosion-resistant sintered Nd-Fe-B permanent magnet material and a preparation method belong to the technical field of magnetic materials. The preparation method comprises the steps as follows: carrying out surface modification to M (the M represents Mg, Al, Cu or mixture of Mg, Al and Cu) powder with an average grain diameter of 50 to 90 nm; then adding the M powder into 2-4 micron neodymium iron boron powder to mix evenly, wherein the adding amount is 0.1 to 2.0 wt% of the 2-4 micron neodymium iron boron powder; orientating the mixture in a 2.5T magnetic field and carrying out compression moulding, placing the compacted object in a vacuum sintering furnace after the compacted object is subjected to 20-40MPa cold static compression; then increasing the temperature, holding the temperature at 200-300 DEG C for 1-2 hours and holding the temperature at 800-900 DEG C for 2-3 hours, sintering for 2 to 6 hours at the temperature of 1020 to 1120 DEG C, and then carrying out two-level heat treatment, wherein the temperature of the first level heat treatment is 900 to 950 DEG C, and the time of the first level heat treatment is 2 to 3.5 hours; the temperature of the second level heat treatment is 480 to 630 DEG C, and the time of the second level heat treatment is 1 to 3 hours, thereby obtaining the sintered Nd-Fe-B permanent magnet material. According to the preparation method of the sintered Nd-Fe-B permanent magnet material of the invention, the coercivity and corrosion resistance of the sintered Nd-Fe-B permanent magnet material are improved by adding nanometer powder and mixed powder of the nanometer powder.

Description

Technical field [0001] The present invention is the field of magnetic material technology, especially the preparation method involving a high -correction and high corrosion resistance. Background technique [0002] ND-FE-B permanent magnet materials have been attracted from people's attention since its discovery in 1982, and widely used in various fields such as communications, electronics, medical and automotive industries.ND-Fe-B permanent magnet material has very high (BH) Max and HCJ, and the advantages of high energy density also make ND-FE-B permanent magnet materials have obtained extensive application and attention in modern industrial and electronic technology.ND-FE-B also makes the instrument, electronic devices, magnetic selection and other equipment more lighter and convenient.And the cost performance of ND-FE-B is very high, which is another reason why ND-FE-B permanent magnet materials are widely used and followed. [0003] The Japanese patent CN101076870A revealed ...

AI Technical Summary

Problems solved by technology

[0007] At present and for a long period of time in the future, two problems still need to be solved in production and research: one is that the coercive force of sintered NdFeB magnets still has a lot of room for improvement; the other is the corrosion resistance of sintered NdFeB magnets still needs to be improved

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