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Heat treatment process of nanometer composite permanent magnetic RE material

A heat treatment method, rare earth permanent magnet technology, applied in heat treatment equipment, heat treatment process control, manufacturing tools, etc., can solve problems such as unfavorable uniform and small exchange coupling ideal microstructure, expansion of temperature difference between soft and hard magnetic phases, etc.

Inactive Publication Date: 2008-02-13
NANJING UNIV
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  • Application Information

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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

Method used

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  • Heat treatment process of nanometer composite permanent magnetic RE material
  • Heat treatment process of nanometer composite permanent magnetic RE material
  • Heat treatment process of nanometer composite permanent magnetic RE material

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Embodiment Construction

[0015] 1. Rare earth metals with a purity greater than 99.8%, pure iron and boron-iron have a ratio of (Nd 1-x Dy x ) 4.5 Fe 77 B 18.5 (x=0.0, 0.1, 0.2, 0.3, 0.4) alloys (considering the volatilization of raw materials during the smelting process, it is generally assumed that pure iron and ferroboron remain unchanged, and the rare earth metals are 3-5% according to the specific smelting process and smelting times The burning loss rate increases the margin), and then put it into a vacuum arc melting furnace for 3-5 times of melting. The vacuum degree during smelting is better than 3×10 -3 Pa.

[0016] 2. After the surface of the smelted ingot is decontaminated and crushed, it is placed in a vacuum quenching furnace and rapidly solidified to obtain samples of amorphous strips or scale-like fragments. The vacuum degree during rapid quenching is better than 3×10 -3 Pa, the line speed is greater than 36m / s.

[0017] 3. The prepared amorphous sample is measured by differenti...

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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...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D11/00C21D1/18B22D11/049
Inventor 都有为李山东
Owner NANJING UNIV
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