Heat treatment process of nanometer composite permanent magnetic RE material

Abstract

The present invention is heat treatment process for nanometer compound phase NdFeB alloy as one nanometer composite permanent magnet RE material. Before heat treatment, the prepared non-crystalline sample is tested through differenrtial thermal analysis at heating rate of 10-30 deg.c / min to measure the crystallizing heat releasing peaks of the soft magnetic phase and the hard magnetic phase in the sample so as to determine heat treatment reference temperature T1off and T2off. The heat treatment process includes first fast heating at 100-400 deg.c / mim to the temperature 10-30 above the soft magnetic phase crystallization end temperature T1off, subsequent heating at 10-30 deg.c / mim to the permanent magnetic phase crystallization end temperature T2off, maintaining for 3-60, and final quenching to room temperature.

Description

1. Technical field [0001] The invention relates to a heat treatment method for a nanocomposite rare earth permanent magnet material, in particular to a heat treatment method for obtaining a nanocomposite rare earth NdFeB permanent magnet material with uniform structure and excellent performance—a graded heat treatment method. 2. Background technology [0002] With its unprecedented excellent comprehensive permanent magnetic properties (its intrinsic magnetic properties are: (BH)max~64MGOe, Ha~73kOe), NdFeB permanent magnets have brought permanent magnet materials into an unprecedented development period. In the late 1980s, McCallum [3] and Coehoorn [4] found that the nanostructured Nd-Fe-B alloy prepared by the rapid quenching method can obtain a high remanence ratio (much greater than 0.5 predicted by the Stoner-Wholfarth theory) without orientation. Nd-Fe-B nanocomposite magnets with low Nd composition, such as Fe-rich Nd 8 Fe 86 B 6 and rich B component Nd 4.5 Fe 7...

AI Technical Summary

Problems solved by technology

However, difficulties were encountered in the specific preparation process. The reason is that after the addition of heavy rare earths, the temperature difference between soft and hard magnetic phases is further expanded (see Figure 2), which is not conducive to obtaining a uniform and fine exchange-coupled ideal microstructure.

[0004] At present, there is no targeted research to obtain a uniform and fine exchange coupling ideal microstructure due to the expansion of the crystallization temperature difference between the soft and hard magnetic phases, thereby improving the performance of permanent magnetic materials

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