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Method and device for preparing iron nitride material by double promotion of nanocrystallization and strong magnetic field

A strong magnetic field, iron nitride technology, applied in the direction of nitrogen-metal/silicon/boron binary compounds, etc., can solve the problems of inability to carry out the nitridation reaction and difficulty in the preparation of α″-Fe, and achieve the effect of inhibiting the formation of

Inactive Publication Date: 2009-12-23
NORTHEASTERN UNIV
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  • Abstract
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  • Claims
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Problems solved by technology

[0007] When performing gas nitriding on α-Fe with a coarse-grained structure, the nitriding reaction cannot proceed when the reaction temperature is lower than 250 °C, and when the reaction temperature is higher, γ′-Fe 4 Nitrides such as N are easy to form, which makes α″-Fe 16 N 2 It is quite difficult to prepare

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  • Method and device for preparing iron nitride material by double promotion of nanocrystallization and strong magnetic field

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Effect test

Embodiment 1

[0021] The method of preparing the iron nitride material is as follows.

[0022] High-purity iron powder (purity ≥ 99.9%) is used as a raw material, and the powder is ball-milled for 25 hours with a high-energy ball mill to obtain iron powder with a grain diameter of 8 nm.

[0023] The prepared nanometer pure iron powder is loaded into the material container in the reactor of the high magnetic field gas nitriding furnace. Introduce hydrogen, control the space velocity to 0.5h -1 , kept at 400°C for 60 minutes, then stopped heating, and cooled naturally to 80°C. At this temperature, a 12T magnetic field is applied by a magnetic field generator, and ammonia gas is introduced at the same time, and the space velocity is controlled to be 0.5h -1 , raise the temperature in the reactor to 180°C and keep it warm for 15 hours, then cool it naturally to room temperature to obtain iron nitride powder, which can be known by X-ray analysis, in which α″-Fe 16 N 2 The composition is abou...

Embodiment 2

[0026] The method of preparing the iron nitride material is as follows.

[0027] High-purity iron powder (purity ≥ 99.9%) is used as a raw material, and the powder is ball-milled for 10 hours with a high-energy ball mill to obtain iron powder with a grain diameter of 50 nm.

[0028] The prepared nano-iron powder is loaded into a material container in a reactor of a strong magnetic field gas nitriding furnace. Introduce hydrogen, control the space velocity to 5h -1 , kept at 450°C for 15 minutes, then stopped heating, and cooled naturally to 60°C. At this temperature, a 20T magnetic field is applied by a magnetic field generator, and ammonia gas is introduced at the same time, and the space velocity is controlled to be 5h -1, raising the temperature in the reactor to 120° C. and keeping it warm for 30 hours, and then naturally cooling to room temperature to obtain an iron nitride powder product. It can be known by X-ray analysis that α″-Fe 16 N 2 The ingredients account fo...

Embodiment 3

[0031] The method of preparing the iron nitride material is as follows.

[0032] Magnetite powder with an average diameter of 30nm is used as raw material. The magnetite powder is loaded into the material container in the high magnetic field gas nitriding furnace reactor. Introduce hydrogen, control the space velocity to 3h -1 , kept at 300°C for 90 minutes, then stopped heating, and cooled naturally to 100°C. At this temperature, a magnetic field of 6T is applied by the magnetic field generator, and ammonia gas is introduced at the same time, and the space velocity is controlled to be 3h -1 , raising the temperature in the reactor to 250° C. and keeping it warm for 8 hours, and then naturally cooling to room temperature to obtain an iron nitride powder product. It can be known by X-ray analysis that α″-Fe 16 N 2 The composition is about 75%.

[0033] During the nitriding reaction process, the ammonia decomposition rate in the furnace is detected by an ammonia decomposit...

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Abstract

The invention relates to a method and a device for preparing iron nitride material by double promotion of nanocrystallization and a strong magnetic field. An electrical heating body and a water cooling sleeve are sequentially arranged outside the inner stainless steel wall of the device, and a magnetic field generating device is arranged outside the water cooling sleeve. The method for preparing iron nitride comprises the following steps: firstly, preparing pure nanometer iron powder or pure nanometer iron films; putting the iron powder or the iron films into the device; leading in hydrogen gas; preserving heat for 10-90 minutes at 300-450 DEG C; naturally cooling to 60-100 DEG C, applying a magnetic filed of 6-20 T by the magnetic field generating device at the temperature, and leading in ammonia gas at the same time; raising the temperature in a reactor to 120-250 DEG C and preserving for 8-30 hours; and naturally cooling to room temperature. In the invention, nitridation reaction can be carried out in the condition of low temperature, which is beneficial to the formation of alfa''-Fe16N2 and the inhibition of the generation of other iron nitride substances. The content of the prepared iron nitride material alfa''-Fe16N2 reaches 65-99 percent.

Description

technical field [0001] The invention belongs to the technical field of magnetic materials, and in particular relates to a preparation method of iron nitride materials. Background technique [0002] Iron nitride mainly includes Fe 2 N, ε-Fe 3 N, γ'-Fe 4 N and α″-Fe 16 N 2 Most of them have excellent soft magnetic properties and good corrosion resistance and oxidation resistance, and are ideal magnetic recording materials and magnetic sensing element materials. In recent years, the research and development of iron nitride materials are quite active in the world, and great progress has been made. [0003] As early as 1972, Tohoku University in Japan passed the 2 In the way of evaporating iron in the atmosphere, a polycrystalline iron nitride film (which is α-Fe and α″-Fe 16 N 2 mixture), the measured saturation magnetization of the α″ phase is 2.83T, which is the material with the largest saturation magnetization found by humans, and is called a “giant magnetic moment” ...

Claims

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Application Information

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IPC IPC(8): C01B21/06
Inventor 佟伟平王长久赫冀成
Owner NORTHEASTERN UNIV
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