Sintered neodymium-iron-boron permanent magnet material and preparation method thereof

Abstract

The invention relates to the technical field of permanent magnet materials, in particular to a sintered neodymium-iron-boron permanent magnet material and a preparation method thereof. The permanent magnet material is prepared from the following raw materials in parts by mass: 5-10 parts of a zinc-neodymium alloy, 8-10 parts of a praseodymium-iron alloy, 0.3-0.8 part of molybdenum disilicide, 0.1-0.5 part of silicon hexaboride, 0.01-0.1 part of an aluminum-rhenium alloy, 0.2-0.9 part of an aluminum-silicon alloy, 1-3 parts of a manganese-nickel alloy, 1-5 parts of a boron-magnesium alloy, 50-65 parts of iron powder and 5-7 parts of a protective film alloy. The residual magnetism and the maximum magnetic energy product of the magnetic material are improved; an efficient stable film is formed on the surface of the magnet in a magnetic material surface coating mode, and the cost is effectively reduced on the premise that the performance and corrosion resistance of the magnet are both considered.

Description

technical field [0001] The invention relates to the technical field of permanent magnets, in particular to a sintered NdFeB permanent magnet material and a preparation method thereof. Background technique [0002] Sintered NdFeB magnets are mainly composed of Nd2Fe14B, Nd-rich phase and B-rich phase, of which Nd2Fe14B is the magnetic phase, which determines the remanence and magnetic energy product, and the Nd-rich phase and the microstructure of the magnet determine the coercive force of the magnet. From the perspective of the magnetization reversal mechanism of sintered NdFeB, it is mainly the nucleation mechanism of the magnetization domain at the grain boundary, and the boundary structure and physical properties of the magnetic phase have an important influence on the coercive force of the magnet. The anisotropy field of (Dy,Tb)2Fe14B is higher than that of Nd2Fe14B, so the addition of heavy rare earth elements Dy and Tb can greatly increase the coercive force of the mag...

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Problems solved by technology

[0003] However, in the current production research of permanent magnets, the main focus is on the improvement of magnetic properties, and there is no targeted technical reserve for the stability of magnetic properties.

For example, a kind of NdFeB magnet whose patent number is CN201810343442.4 is obtained by two formulations of the first NdFeB alloy and the second NdFeB alloy through secondary compression molding and high-temperature sintering to reduce the concentration of heavy rare earth elements. The amount of usage, reducing production costs, and obtaining better comprehensive magnetic properties; however, no attempt has been made to the continuity of the performance of the magnet, which is not conducive to the improvement of the overall performance of the magnet

Another example is the preparation method of an anti-oxidation NdFeB magnet whose patent number is CN201810254057.2. The NdFeB magnet is obtained by sintering and tempering the NdFeB magnet green body, which prevents the rare earth in the NdFeB magnet green body React with oxygen to avoid the difference in liquid phase shrinkage during sintering, resulting in oxidation deformation; but it can only prevent oxidation in the production process, and lacks consideration for environmental variables such as oxidation and corrosion in the use environment of the magnet

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