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

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...

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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 resistivity of this dual-phase coupling absorbing material is too low and the dielectric constant is too large. As a wave-absorbing material, it is easy to generate eddy current, which is not conducive to the absorption of electromagnetic waves

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