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Method for preparing carbonyl iron powder absorbent for low-frequency electromagnetic wave absorption material

A technology of carbonyl iron powder and absorbing materials, which is applied in the field of modification of carbonyl iron powder soft magnetic materials, can solve problems such as impedance mismatch, increase in dielectric constant, and decline in wave-absorbing performance, and achieve improved magnetic permeability and low-frequency absorption Improved wave performance and reduced dielectric constant

Active Publication Date: 2016-01-27
南京南大波平电子信息有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, while the magnetic permeability of flaky carbonyl iron powder increases, its dielectric constant also increases significantly, resulting in impedance mismatch, and the absorption performance will be reduced.

Method used

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  • Method for preparing carbonyl iron powder absorbent for low-frequency electromagnetic wave absorption material
  • Method for preparing carbonyl iron powder absorbent for low-frequency electromagnetic wave absorption material
  • Method for preparing carbonyl iron powder absorbent for low-frequency electromagnetic wave absorption material

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Effect test

Embodiment 1

[0022] Restore 500g of spherical carbonyl iron powder at 400°C in a hydrogen atmosphere to reduce the hardness of the carbonyl iron powder; take 200g of the reduced powder, and use a vibrating ball mill for ball milling, the ball-to-material ratio is 5:1, the diameter of the tungsten carbide grinding rod is 5mm, the length is 10mm, and the milling time For 20 hours, the process control agent uses absolute ethanol, and vacuum drying after completion; the flake carbonyl iron powder is subjected to low-temperature oxidation treatment in a wet hydrogen atmosphere, the temperature is 100 ° C, the time is 1 hour, and the dew point temperature is 10 ° C. figure 1 It is the SEM picture of the carbonyl iron powder prepared under this condition. The carbonyl iron powder and polyurethane rubber prepared under this condition were compounded at a mass ratio of 8:1 to prepare a microwave-absorbing material. image 3 It is the electromagnetic parameter diagram of the carbonyl iron powder com...

Embodiment 2

[0024] Restore 500g of spherical carbonyl iron powder at 500°C in a hydrogen atmosphere to reduce the hardness of the carbonyl iron powder; take 200g of the reduced powder, and use a vibrating ball mill for ball milling with a ball-to-material ratio of 10:1. For 10 hours, the process control agent uses acetone, and vacuum drying after completion; the flake carbonyl iron powder is subjected to low-temperature oxidation treatment in a wet hydrogen atmosphere, the temperature is 500 ° C, the time is 4 hours, and the dew point temperature is 40 ° C. figure 2 It is the SEM picture of the carbonyl iron powder prepared under this condition. Under this condition, carbonyl iron powder and polyurethane rubber are compounded at a mass ratio of 8:1 to prepare a wave-absorbing material. Figure 6 It is the electromagnetic parameter diagram of the carbonyl iron powder composite absorbing material prepared under this condition.

Embodiment 3

[0026] Restore 500g of spherical carbonyl iron powder at 600°C in a hydrogen atmosphere to reduce the hardness of the carbonyl iron powder; take 200g of the reduced powder, and use a vibrating ball mill for ball milling with a ball-to-material ratio of 15:1. The diameter of the tungsten carbide grinding rod is 20mm and the length is 40mm. for 5h. The process control agent uses heptane, and vacuum drying after completion; the flake carbonyl iron powder is subjected to low-temperature oxidation treatment in a wet hydrogen atmosphere, the temperature is 350 ° C, the time is 3 hours, and the dew point temperature is 20 ° C. image 3 It is the SEM picture of the carbonyl iron powder prepared under this condition. Under this condition, carbonyl iron powder and polyurethane rubber are compounded at a mass ratio of 8:1 to prepare a wave-absorbing material. Figure 7 It is the electromagnetic parameter diagram of the carbonyl iron powder composite absorbing material prepared under thi...

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Abstract

The invention relates to a method for preparing a carbonyl iron powder absorbent for a low-frequency electromagnetic wave absorption material. The method comprises the following steps: firstly, reducing spherical carbonyl iron powder in a hydrogen atmosphere at a high temperature to reduce the carbon oxygen content of the carbonyl iron powder and decrease the hardness of the carbonyl iron powder; secondly, adding a process control agent to perform wet-method ball milling in a vibrating ball mill to prepare sheet-like carbonyl iron powder; finally, treating the sheet-like carbonyl iron powder from which the process control agent is removed in a wet hydrogen atmosphere to obtain high-permeability sheet-like carbonyl iron powder, wherein a weak oxidation layer is arranged on the surface of the high-permeability sheet-like carbonyl iron powder. According to the method, the carbonyl iron powder can be efficiently transformed from a spherical shape into a sheet shape, the magnetic conductivity of the carbonyl iron powder can be obviously improved, a dielectric constant is reduced, and the absorption performance of the carbonyl iron powder at a low-frequency electromagnetic wave is improved.

Description

technical field [0001] The invention belongs to a method in the field of magnetic wave-absorbing materials, and in particular relates to a method for modifying carbonyl iron powder soft magnetic materials. Background technique [0002] With the widespread use of microwave absorbing materials in military and civilian products, magnetic absorbers, as their key components, have been studied more and more deeply. Carbonyl iron powder is widely used in the field of microwave absorbing materials because it has both dielectric loss and magnetic loss. Especially in the high-frequency (8-40GHz) frequency band, it has excellent wave-absorbing performance. In this range, wave-absorbing materials in any frequency band can be prepared by changing the content of the absorber and fine-tuning the thickness of the material, and the thickness is thin and the performance is excellent. It can be widely used in military stealth, wave-absorbing loads, electromagnetic compatibility and other fiel...

Claims

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Application Information

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IPC IPC(8): C01G49/16
Inventor 张金祥黄忠明王娜王金平
Owner 南京南大波平电子信息有限公司
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