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An iron-based magnetic foam absorbing material with low-frequency broadband absorbing performance and its preparation method

A technology of magnetic foam and wave absorbing material, which can be applied in the fields of magnetic field/electric field shielding, electrical components, etc., and can solve the problems of increasing the technological difficulty of iron-based magnetic three-dimensional structural materials.

Active Publication Date: 2021-07-06
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the flaked powder is generally larger than 40 μm in diameter, it is difficult to suspend in the solution, which greatly increases the process difficulty of preparing iron-based magnetic three-dimensional structure materials.

Method used

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  • An iron-based magnetic foam absorbing material with low-frequency broadband absorbing performance and its preparation method
  • An iron-based magnetic foam absorbing material with low-frequency broadband absorbing performance and its preparation method
  • An iron-based magnetic foam absorbing material with low-frequency broadband absorbing performance and its preparation method

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preparation example Construction

[0034] The preparation process of the iron-based magnetic foam of the present invention is characterized by the introduction of an appropriate amount of suspending agent in the raw material formula, which can effectively increase the suspension time of the flake iron-based magnetic powder in the slurry; And strong mechanical stirring technology, this technology effectively makes the flaky iron-based magnetic powder not settle in the solution for a long time, and disperses evenly.

[0035] The present invention provides a preparation method for the above-mentioned iron-based magnetic foam wave-absorbing material, and the specific process flow is as follows:

[0036] (1) Preparation of slurry

[0037] Mix iron-based magnetic powder, resin, curing agent, suspending agent and solvent in a certain proportion, after ball milling, add solvent, the solute in the slurry accounts for 10% to 50% of the total, and pour it into an ultrasonic stirrer ( image 3 ), suspending the iron powde...

Embodiment 1

[0045]Mix 150-180 μm flake sendust powder, bismaleimide resin, diaminodiphenylmethane and fumed silica at a weight ratio of 50%: 40%: 8%: 2%, and add dimethyl Acetamide (solute content is 10%), ball milled for 0.5 hours, filtered through a 40-mesh screen, stirred by an ultrasonic mixer for 10 minutes, and then made into a slurry. The polyurethane foam with a pore size of 0.1mm was cut into 100×100×30mm pieces and then immersed in the In the slurry, take out and squeeze out the excess slurry, put it into a centrifuge for centrifugation, and the centrifugal speed is 1500 rpm. After taking it out, blow the hole wall with a high-pressure airflow, put it into an oven for curing after air drying, and the curing temperature gradient is 1 Heat at 100°C for 10 minutes, raise to 150°C for 10 minutes, and raise to 300°C for 1 hour. The above process is repeated several times until the predetermined volume fraction of 20% is reached. Then, the sample is put into a high-temperature and hig...

Embodiment 2

[0048] Mix 0.5-1 μm flake carbonyl iron powder, epoxy resin, polyamide and precipitated silica with a weight ratio of 70%: 20%: 5%: 5%, add absolute ethanol (solute content is 10%), Ball mill for 1 hour, filter with 80-mesh sieve, and make a slurry after being stirred by an ultrasonic mixer. Cut the polyethylene foam with a pore size of 5mm into pieces and immerse in the slurry. Take out and squeeze out the excess slurry, and put it in the centrifuge. Centrifuge in the machine with a centrifugal speed of 200 rpm. After taking it out, blow the hole wall with high-pressure airflow. After air-drying, put it in an oven for curing. The curing program is to heat at 60°C for 10 minutes. The above process is repeated many times until the predetermined volume fraction of 30% is reached. Then, put the sample into a high-temperature and high-pressure reaction vessel with a pressure of 5 MPa, raise the temperature to 150° C., keep the temperature for 2 hours, and remove the prefabricated ...

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Abstract

The invention discloses an iron-based magnetic foam wave-absorbing material with low-frequency broadband wave-absorbing performance and a preparation method thereof, belonging to the technical field of electromagnetic shielding and microwave loss functional materials. In this method, iron-based magnetic powder, resin, curing agent and suspending agent are first mixed, and ultrasonically mechanically stirred to form a uniform suspension slurry; the slurry is hung and applied to the template, and the remaining material is removed and then heated and solidified; the template is removed by high temperature and high pressure; foam reinforcement Resin is sucked into the surface micropores and the pores left after removing the template, and the mechanics are enhanced. The invention solves the problem that the flaky iron-based powder cannot be suspended in the solution by adding the suspending agent to the raw material and using ultrasonic mechanical stirring in the material-hanging process. The iron-based magnetic foam prepared by the invention has a low-frequency broadband wave-absorbing effect, and has better wave-absorbing performance in the 1.14-2.4GHz frequency band.

Description

technical field [0001] The invention relates to the technical field of electromagnetic shielding and microwave loss functional materials, in particular to an iron-based magnetic foam wave-absorbing material with low-frequency broadband wave-absorbing performance and a preparation method thereof. Background technique [0002] With the development of electromagnetic wave technology, more and more attention has been paid to the research of electromagnetic wave absorbing materials. In terms of civilian use, microwave-absorbing materials are required for electromagnetic compatibility and shielding between micro-equipment components; in order to prevent radiation damage to the human body from equipment radiation sources, equipment needs to use microwave-absorbing materials to absorb harmful electromagnetic waves; microwave test darkrooms need to be paved with absorbing Wave material to reduce environmental interference. In terms of military use, with the development of detection ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J9/42C08L75/04C08L23/06H05K9/00
CPCC08J9/42C08J2323/06C08J2375/04C08J2461/00C08J2461/06C08J2463/00C08J2479/08H05K9/0092
Inventor 张劲松林立海李处森李万崇
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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