Wave suction composite material with nanocrystalline structure and method for producing the same

A composite material and nanocrystalline technology, applied in the field of wave-absorbing materials, can solve the problems of unfavorable electromagnetic wave absorption, easy generation of eddy current, large dielectric constant, etc., and achieve the effects of anti-oxidation, low cost, wide shielding band, and high frequency band

Inactive Publication Date: 2009-05-13
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At the same time, the change of the coercive force directly affects the change of the natural resonance peak of the absorbing material, which can meet the needs of electromagnetic wave absorption in a certain band, but the resistiv...

Method used

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  • Wave suction composite material with nanocrystalline structure and method for producing the same
  • Wave suction composite material with nanocrystalline structure and method for producing the same
  • Wave suction composite material with nanocrystalline structure and method for producing the same

Examples

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Effect test

Embodiment 1

[0031] Melt 25 parts by weight of samarium and 75 parts by weight of pure iron into an ingot under the protection of argon, heat-treat at 1200°C for 4 hours, then explode with hydrogen at 200°C for 1 hour, break into powder, and hydrogenate at 700°C Disproportionation + recombination (HDDR) for 1 hour, nitriding at 600°C for 2 hours to prepare a SmFeN permanent magnet material, decomposing the magnetic powder at a temperature of 700°C for 20 minutes to obtain a SmFeN / α-Fe / SmN composite material, and then ball milling and flattening After chemical treatment, the alloy powder and paraffin were mixed in a weight ratio of 5:1, and then pressed into a ring shape (D=7mm, d=3.01mm, h=3mm), the magnetic permeability of the sample μ r , dielectric constant ε r Measured with Agilent E8720 electromagnetic wave vector network analyzer. The imaginary part of the permittivity ε″ reaches 14 at a frequency of 5GHz, the real part of the permeability μ′ is up to 2.9, the imaginary part of the ...

Embodiment 2

[0033] 2 parts by weight of samarium and 98 parts by weight of pure iron were melted into ingots under the protection of argon, and after heat treatment at 700°C for 60 hours, hydrogenation disproportionation + recombination (HDDR) at 650°C for 2 hours to prepare nanocrystals SmFe / α-Fe / SmHx was nitrided at 400°C for 40 hours to form a SmFeN / α-Fe / SmN composite material, and after ball milling and flattening, the alloy powder and paraffin were mixed in a weight ratio of 5:1. Then pressed into a ring shape (D=7mm, d=3.01mm, h=3mm), the electromagnetic parameter μ of the sample r , ε r Measured by the Agilent E8720 electromagnetic wave vector network analyzer, ε″ reaches 13 at a frequency of 6GHz, μ′ reaches a maximum of 3.2, μ″ reaches a maximum of 1.0, its absorption peak reaches -25 decibels (dB), and the absorption rate is less than -10dB The bandwidth is 2.5GHz, the absorbing curve is detailed in figure 2 shown.

Embodiment 3

[0035] 14 parts by weight of samarium, 6 parts by weight of neodymium and 80 parts by weight of pure iron were melted into ingots under the protection of argon, and after heat treatment at a temperature of 1000 ° C for 10 hours, hydrogen disproportionation + recombination (HDDR) at a temperature of 750 ° C for 5 hours , and then nitriding at a temperature of 600°C for 2 hours to prepare a NdFeN / SmFeN permanent magnet material, and then decomposing the magnetic powder at a temperature of 720°C for 20 minutes to obtain a SmFeN / NdFeN / α-Fe / NdN / SmN composite material, and then ball milling After flattening treatment, the alloy powder and paraffin are mixed in a weight ratio of 5:1, and then pressed into a ring shape (D=7mm, d=3.01mm, h=3mm), the electromagnetic parameter μ of the sample r , ε rMeasured by the Agilent E8720 electromagnetic wave vector network analyzer, ε″ reaches 10 at a frequency of 3GHz, μ′ reaches a maximum of 3.5, μ″ reaches a maximum of 1.2, its absorption peak...

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Abstract

The invention discloses a microwave absorbing composite material with a nanometer crystalline structure and a method for preparing the same. The method is characterized by comprising the following steps: smelting 2 to 70 weight portions of rare earth element, 5 to 98 weight portions of iron and 0 to 25 weight percent of microelement into cast ingots under the protection of argon gas; after heat treatment at a temperature of between 700 and 1,200 DEG C for 4 to 60 hours, reacting the prepared rare earth-iron alloy with hydrogen gas at a temperature of between 0 and 700 DEG C for 0.5 to 2 hours; crushing or ball milling the rare earth-iron alloy into fine powder; performing hydrogenation dismutation and dehydrogenation recombination on the fine powder at a temperature of between 500 and 1,000 DEG C for 1 to 5 hours; performing nitridation at a temperature of between 400 and 600 DEG C for 2 to 40 hours or performing the nitridation directly at the temperature of between 400 and 600 DEG C for 10 to 60 hours to produce rare earth iron-nitrogen magnetic powder with the nanometer crystalline structure; and heating up and decomposing the prepared rare earth iron-nitrogen magnetic powder at a temperature of between 100 and 750 DEG C for 5 to 60 minutes, or oxidizing the powder by air at a temperature of between 100 and 400 DEG C for 0.5 to 3 hours, and then preparing the powder into a three-phase coupled composite material consisting of dielectric phase rare earth nitride or rare earth oxide or rare earth oxynitride and magnetic phase alpha-Fe and rare earth hard magnetic phase with different contents through ball milling.

Description

technical field [0001] The invention relates to a wave-absorbing composite material with a nanocrystalline structure and a preparation method thereof, belonging to the field of wave-absorbing materials. Background technique [0002] With the rapid development of electronic technology, electromagnetic radiation in people's lives is increasing; in order to meet the needs of modern warfare, microwave-absorbing materials will be widely used in weapons, and research on materials with microwave-absorbing capabilities is of great importance to both military and civilian applications. practical value. At present, traditional wave-absorbing materials such as ferrite, which have been widely used, have small relative permittivity εr, small saturation magnetization, and low relative permeability μr. Due to the limitation of Snoek limit, especially the permeability The imaginary part of is quite small at the GHz frequency, and it is difficult to use it in the 1-5GHz band commonly used i...

Claims

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Application Information

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IPC IPC(8): C22C38/00H01F1/01C22C1/04H05K9/00
Inventor 刘颖陈先富叶金文连利仙涂铭旌
Owner SICHUAN UNIV
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