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Nanocrystalline ultra-fine alloy powder electromagnetic wave absorbent and preparation method thereof

A technology of absorbent and alloy powder, which is applied in the direction of electrical components, magnetic field/electric field shielding, etc., can solve the problems of low magnetic permeability of ferrite and poor microwave absorption performance, and achieve the effect of adjusting the absorption frequency band

Active Publication Date: 2008-11-05
GUANGDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is a more serious problem with ferrite: at higher microwave frequencies, the magnetic permeability of ferrite is generally relatively small, and the microwave absorption performance becomes poor.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Mix ferric nitrate and cobalt nitrate with deionized water in a molar ratio of 1:1, then add citric acid in a molar ratio of ferric nitrate: citric acid = 5: 6, cobalt nitrate: citric acid = 5: 9, and prepare a uniform After the solution, add ammonia water to adjust the pH value of the solution to 7, put the sol in a drying oven, and dry it at 110°C for 24 hours to form a xerogel, and the xerogel is heated to self-spread to obtain an oxide powder. Ball mill the oxide for 1 hour, then place it in a quartz tube, introduce 50 sccm of hydrogen gas, heat up to 800°C with the furnace, keep it warm for 1 hour, then quickly air-cool it to 150°C, take it out, and collect the product nanocrystalline ultrafine alloy powder Fe 50 co 50 (at%). Nanocrystalline Ultrafine Alloy Powder Fe 50 co 50 It is Fe, Co binary alloy powder, wherein the atomic percentage of Fe is 50%, and the atomic percentage of Co is 50%. Using the prepared nanocrystalline alloy powder microwave absorber Fe ...

Embodiment 2

[0020] Mix ferric nitrate and nickel nitrate with deionized water in a molar ratio of 1:3, then add citric acid in a molar ratio of ferric nitrate: citric acid = 5: 6, nickel nitrate: citric acid = 5: 9, and prepare a uniform After the solution, add ammonia water to adjust the pH value of the solution to 7, put the sol in a drying oven, and dry it at 110°C for 24 hours to form a xerogel, and the xerogel is heated to self-spread to obtain an oxide powder. Ball mill the oxide for 2 hours, then place it in a quartz tube, pass in 50 sccm of hydrogen, heat up to 900°C with the furnace, keep it warm for 3 hours, then quickly air-cool it to 150°C, take it out, and collect the product nanocrystalline ultrafine alloy powder Fe 25 Ni 75 (at%). Nanocrystalline Ultrafine Alloy Powder Fe 25 Ni 75 It is Fe, Ni binary alloy powder, wherein the atomic percentage of Fe is 25%, and the atomic percentage of Ni is 75%. Using the prepared nanocrystalline alloy powder microwave absorber Fe 25 ...

Embodiment 3

[0022] Mix ferric nitrate and nickel nitrate with deionized water in a molar ratio of 1:1, then add citric acid in a molar ratio of ferric nitrate: citric acid = 5: 6, nickel nitrate: citric acid = 5: 9, and prepare a uniform After the solution, add ammonia water to adjust the pH value of the solution to 7, put the sol in a drying oven, and dry it at 110°C for 24 hours to form a xerogel, and the xerogel is heated to self-spread to obtain an oxide powder. Ball mill the oxide for 3 hours, then place it in a quartz tube, feed 50 sccm of hydrogen gas, heat up to 900°C with the furnace, keep it warm for 1 hour, then quickly air-cool it to 150°C, take it out, and collect the product nanocrystalline ultrafine alloy powder Fe 50 Ni 50 (at%). Nanocrystalline Ultrafine Alloy Powder Fe 50 Ni 50 It is Fe, Ni binary alloy powder, wherein the atomic percentage of Fe is 50%, and the atomic percentage of Ni is 50%. Using the prepared nanocrystalline alloy powder microwave absorber Fe 50 ...

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PUM

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Abstract

The invention discloses a nanocrystalline ultra-fine alloy powder electromagnetic wave absorbent and preparation method thereof. The absorbent is a binary or ternary alloy powder combined by Fe, Co, Ni, wherein Fe, Co, Ni is 10 to 90 percent of the atom percentage of the alloy. The absorbent is prepared by self-spread incendiary method, the magnetic conductivity of metal powder under microwave frequency can be regulated by heat treatment in the preparation process, thereby the effect of regulating the band of wave-absorbing can be achieved. The nanocrystalline ultra-fine alloy powder electromagnetic wave absorbent has complex permeability and complex dielectric constant, the magnetic conductivity of the microwave permeability is higher, which can make up the shortcomings of the ferrite series magnetic materials, such as large specific gravity and no ideal high-frequency characteristic; the surface effect volume effect and quantum size effect of the nanometer particle makes the nanometer particle generate a plurality of physical and chemical effects different from block materials. The electromagnetic wave absorbent of the invention has good absorbing property to electromagnetic wave, specifically to high-frequency electromagnetic.

Description

technical field [0001] The invention relates to a nanocrystalline superfine alloy powder electromagnetic wave absorber and a preparation method thereof. Background technique [0002] At present, according to the loss mechanism, there are two main types of electromagnetic wave absorbers: (1) dielectric loss absorbers, such as carbon black, carbon fiber, graphite, SiC fiber, etc.; (2) magnetic loss absorbers, such as iron oxide body, carbonyl iron powder, metal micropowder, etc. The dielectric loss absorbing material has a large thickness and a narrow absorption frequency band, and the magnetic absorber can widen the frequency band and reduce the thickness. Ferrite has a long history as an absorber and is one of the commonly used wave-absorbing materials. It has both a certain dielectric loss and a large magnetic loss in the range of tens to hundreds of MHz. Has good absorption properties. However, there is a more serious problem with ferrite: at higher microwave frequencie...

Claims

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Application Information

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IPC IPC(8): H05K9/00B22F9/22
Inventor 张海燕吴子秋张坚
Owner GUANGDONG UNIV OF TECH