Method for preparing Sm2Fe17Nx magnetic powder by taking ammonium carbonate as nitrogen source positive pressure samarium iron nitride alloy

A technology of samarium-iron nitride and ammonium carbonate, which is applied in the direction of magnetic materials, magnetic objects, electrical components, etc., can solve the problems of uneven distribution of nitrogen atoms, low utilization rate of nitrogen source, and low degree of nitriding, so as to improve the uniformity of composition properties, uniform composition, and sufficient nitriding effect

Active Publication Date: 2015-03-04
ZHEJIANG UNIV OF TECH
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Problems solved by technology

[0007] In order to solve the deficiencies in the prior art in the nitriding of samarium-iron alloys, the flowing gaseous nitrogen source has low nitriding degree due to low pressure, uneven distribution of nitrogen atoms, low utilization rate of nitrogen source and difficult control, the present invention provides a A method for greatly increasing the degree of nitriding, improving the uniformity of magnetic powder composition, fully improving the anisotropy characteristics of magnetic powder, and preparing high-performance samarium-iron-nitrogen magnetic properties

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  • Method for preparing Sm2Fe17Nx magnetic powder by taking ammonium carbonate as nitrogen source positive pressure samarium iron nitride alloy

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] (1) First put 6g of samarium-iron alloy powder into crucible 1, put 1.90g of ammonium carbonate solid, 2.0g of sodium hydroxide and 5g of calcium oxide into crucible 2 in order from bottom to top, and put 0.1g of metal calcium particles into crucible 2. into container 3;

[0041] (2) Then put the crucible 1 and the crucible 2 in a temperature-resistant and pressure-resistant container 4 with a volume of 200ml. ) vacuum, vacuum degree ≤ 0.05MPa;

[0042] (3) Then the crucible 2 is heated to thermally decompose the ammonium carbonate; simultaneously, the crucible 1 is heated to 70° C., and kept for 60 minutes, then heated to 380° C. for nitriding, and kept for 2 hours; cooled to 350° C. for homogenization heat treatment, Homogenization heat treatment for 4h; finally lowered to room temperature to obtain Sm 2 Fe 17 N x magnetic powder.

[0043] Assuming that the increase in the mass of the magnetic powder is only related to the introduction of nitrogen atoms, the weig...

Embodiment 2

[0047] (1) First put 6g of samarium iron alloy powder into crucible 1, put 2.88g of ammonium carbonate solid, 4.5g of sodium hydroxide and 7g of calcium oxide into crucible 2 in order from bottom to top, and put 0.1g of metal calcium particles into crucible 2. into container 3;

[0048] (2) Then put the crucible 1 and the crucible 2 in a temperature-resistant and pressure-resistant container 4 with a volume of 200ml. ) vacuum, vacuum degree ≤ 0.05MPa;

[0049] (3) Then the crucible 2 is heated to thermally decompose the ammonium carbonate; at the same time, the crucible 1 is heated to 70° C. and kept for 60 minutes, then heated to 400° C. for nitriding, and kept for 2 hours; cooled to 350° C. for homogenization heat treatment, Homogenization heat treatment for 4h; finally lowered to room temperature to obtain Sm 2 Fe 17 N x magnetic powder.

[0050] Assuming that the increase in the mass of the magnetic powder is only related to the introduction of nitrogen atoms, the wei...

Embodiment 3

[0054] (1) First put 6g of samarium iron alloy powder into crucible 1, put 2.88g of ammonium carbonate solid, 4.5g of sodium hydroxide and 7g of calcium oxide into crucible 2 in order from bottom to top, and put 0.1g of metal calcium particles into crucible 2. into container 3;

[0055] (2) Then put the crucible 1 and the crucible 2 in a temperature-resistant and pressure-resistant container 4 with a volume of 200ml. ) vacuum, vacuum degree ≤ 0.05MPa;

[0056] (3) Then the crucible 2 is heated to thermally decompose the ammonium carbonate; at the same time, the crucible 1 is heated to 70° C. and kept for 60 minutes, then heated to 380° C. for nitriding, and kept for 6 hours; cooled to 350° C. for homogenization heat treatment, Homogenization heat treatment for 8h; finally lowered to room temperature to obtain Sm 2 Fe 17 N x magnetic powder.

[0057] Assuming that the increase in the mass of the magnetic powder is only related to the introduction of nitrogen atoms, the wei...

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Abstract

The invention discloses a method for preparing Sm2Fe17Nx magnetic powder by taking ammonium carbonate as nitrogen source positive pressure samarium iron nitride alloy. The method comprises the following steps: (1) placing samarium iron alloy powder in a nitriding reaction container, and placing ammonium carbonate solid, a CO2 remover and a drying agent into an ammonia generator in sequence from bottom to top; (2) placing the nitriding reaction container and the ammonia generator in a closed temperature-resistant and pressure-resistant container, and vacuuming the temperature-resistant and pressure-resistant container, wherein the vacuum degree is less than or equal to 0.05 MPa; (3) heating the ammonia generator to thermally decompose the ammonium carbonate; meanwhile heating the nitriding reaction container to 55-100 DEG C, preserving the heat for 10-100 min, then raising the temperature to 300-500 DEG C to perform nitridation and preserving the heat for 1-10 h; cooling to 100-350 DEG C to perform homogenization heat treatment for 1-20 h; finally cooling to room temperature to obtain the Sm2Fe17Nx magnetic powder. According to the method, solid-state ammonium carbonate is heated in the closed container to produce ammonia serving as a nitrogen source so as to uniformly and completely nitrogenize the samarium iron alloy.

Description

technical field [0001] The invention relates to the technical field of magnetic material preparation, in particular to a method for preparing Sm 2 Fe 17 N x Magnetic powder method. Background technique [0002] Since 1990 Coey et al. discovered samarium iron nitrogen (Sm 2 Fe 17 N x ) compound, because its anisotropic field at room temperature reaches 15T~16T, which is about 2~3 times that of NdFeB, the theoretical magnetic energy product (BH) max 472kJ / m 3 , slightly lower than NdFeB (512kJ / m 3 ), and the corrosion resistance and oxidation resistance are superior to the "Magnetic King" NdFeB, which provides the possibility to meet the new needs of permanent magnet materials, and has become one of the most promising new generation of hard magnetic materials. In addition, SmFeN has a higher Curie temperature than NdFeB (470°C, NdFeB is 310°C), so that SmFeN magnetic powder can be used to prepare bonded magnets with higher service temperature, which is It is possible ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/00H01F1/047
Inventor 郑精武陈海波乔梁蔡伟姜力强车声雷应耀
Owner ZHEJIANG UNIV OF TECH
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