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CN-122029698-A - Microwave band electromagnetic wave absorbing material and method for manufacturing same

CN122029698ACN 122029698 ACN122029698 ACN 122029698ACN-122029698-A

Abstract

An embodiment of the present invention provides a method for manufacturing an electromagnetic wave absorbing material, the method including a step of mixing powder including at least one selected from the group consisting of a Ca precursor, a Ba precursor, a Sr precursor, a Re precursor, a Me precursor, a Co precursor, and an Fe precursor, a step of performing a first heat treatment on the mixed powder, a step of ball-milling the heat-treated powder, and a step of performing a second heat treatment on the ball-milled powder, thereby manufacturing an electromagnetic wave absorbing material including W-type hexagonal ferrite (W-type hexaferrite) represented by chemical formula 1. The present invention is a result of a study on a development of a microwave absorber for 5G communication (28 GHz) by the university of first-order university, which is supported by Changxing (strain).

Inventors

  • CUI CHENGMIN
  • LI ZHENGXIONG
  • LIN ENZHU
  • LIU XIANGREN
  • XU HEZHEN

Assignees

  • 株式会社昌星
  • 首尔大学校产学协力团

Dates

Publication Date
20260512
Application Date
20240514
Priority Date
20240408

Claims (12)

  1. 1. A method for manufacturing an electromagnetic wave absorbing material, comprising: mixing a powder containing at least one selected from the group consisting of a Ca precursor, a Ba precursor, a Sr precursor, a Re precursor, a Me precursor, a Co precursor, and an Fe precursor; A step of performing a first heat treatment on the mixed powder; ball milling the heat treated powder, and A step of performing a second heat treatment on the ball-milled powder, Thereby manufacturing an electromagnetic wave absorbing material comprising W-type hexaferrite represented by the following chemical formula 1: Chemical formula 1 Ca a Ba b Sr 1-a-b-c Re c Co 2+ x Me 2+ 2-x Fe 3+ 16 O 27 Wherein, in the chemical formula 1, The Re is at least one selected from the group consisting of rare earth elements; The Me 2+ is at least one selected from the group consisting of divalent transition metals; The a is 0.0 to 1.0; The b is 0.0 to 1.0; the c is 0.0 to 1.0; And x is 0.0 to 2.0.
  2. 2. The method of manufacturing an electromagnetic wave absorbing material according to claim 1, wherein in the chemical formula 1, the x is 0.0 to 0.3.
  3. 3. The method for producing an electromagnetic wave absorbing material according to claim 1, wherein in the chemical formula 1, the Me 2+ is at least one selected from the group consisting of Zn 2+ 、Fe 2+ 、Ni 2+ 、Mn 2+ and Mg 2+ .
  4. 4. The method for producing an electromagnetic wave absorbing material according to claim 1, wherein the first heat treatment step is performed at a temperature ranging from 1200 ℃ to 1400 ℃.
  5. 5. The method of producing an electromagnetic wave absorbing material according to claim 1, wherein the content of Fe 2+ ions in 2 moles of the divalent transition metal contained in the chemical formula 1 is 0.5 mole or less in the W-type hexaferrite represented by the chemical formula 1.
  6. 6. The method for producing an electromagnetic wave absorbing material according to claim 1, wherein the second heat treatment step is performed at a temperature ranging from 1200 ℃ to 1400 ℃.
  7. 7. The method for producing an electromagnetic wave absorbing material according to claim 1, wherein the second heat treatment step is sintering in air.
  8. 8. An electromagnetic wave absorbing material comprising a W-type hexaferrite represented by the following chemical formula 1: Chemical formula 1 Ca a Ba b Sr 1-a-b-c Re c Co 2+ x Me 2+ 2-x Fe 3+ 16 O 27 Wherein, in the chemical formula 1, The Re is at least one selected from the group consisting of rare earth elements; The Me 2+ is at least one selected from the group consisting of divalent transition metals; The a is 0.0 to 1.0; The b is 0.0 to 1.0; the c is 0.0 to 1.0; And x is 0.0 to 2.0.
  9. 9. The electromagnetic wave absorbing material according to claim 8, wherein a content of Fe 2+ ions in 2 moles of the divalent transition metal contained in the chemical formula 1 is 0.5 mole or less in the W-type hexaferrite represented by the chemical formula 1.
  10. 10. The electromagnetic wave absorbing material according to claim 8, wherein the electromagnetic wave absorbing material has a ferromagnetic resonance (Ferromagnetic resonance, FMR) frequency in a frequency band of 26.5GHz or more and 40GHz or less.
  11. 11. The electromagnetic wave absorbing material according to claim 8, wherein in the chemical formula 1, the x is 0.0 to 0.3.
  12. 12. The electromagnetic wave absorbing material according to claim 8, wherein in the chemical formula 1, the Me 2+ is at least one selected from the group consisting of Zn 2+ 、Fe 2+ 、Ni 2+ 、Mn 2+ and Mg 2+ .

Description

Microwave band electromagnetic wave absorbing material and method for manufacturing same Technical Field The present invention relates to an electromagnetic wave absorbing material and a method for manufacturing the same, and more particularly, to a method for manufacturing an electromagnetic wave absorbing material for the Ka band (26.5 GHz to 40 GHz) in the 5G communication field, the material comprising W-type hexaferrite (W-type hexaferrite) containing no or only a very small amount of Fe 2+ ions. Background With the development of information communication technology, technologies of the next generation such as automatic driving automobiles, internet of things (IoT), smart phones, artificial Intelligence (AI), virtual reality and the like are actively developed. In addition, electronic devices tend to be miniaturized, and the available operating frequency is gradually increased, and the processed data and traffic are drastically increased. Accordingly, communication between electronic devices becomes complicated and various, and there is a problem of communication errors due to frequency interference, etc., so that the necessity for electromagnetic shielding and absorption is increasing. The hexaferrite has high magnetic anisotropy, and is a material suitable for use as an electromagnetic wave absorber in the GHz band frequency range. Therefore, in order to realize stable communication of electronic devices in the Ka band (26.5 GHz to 40 GHz) of the 5G communication field, electromagnetic interference must be eliminated, and thus, hexaferrite capable of exhibiting excellent absorption characteristics in the frequency band of several GHz to several tens of GHz is increasingly applied in the 5G communication technology. However, conventionally, as electronic devices and traffic increases, interference from surrounding device signals occurs, and thus, there is a problem of electromagnetic interference (Electromagnetic interference, EMI) that may cause a decrease in functions or cause malfunction. In particular, for electronic devices closely related to life such as unmanned aerial vehicles, automatic driving automobiles, implanted biosensors, etc., serious problems may be caused. In order to suppress such EMI problems, electromagnetic compatibility (Electromagnetic compatibility, EMC), which is an international standard, has been regulated and regulated as a mandatory regulation. Therefore, one of the methods introduced to meet EMC standards at the product design stage is an electromagnetic shielding and absorption technique for blocking the ingress and egress of electromagnetic waves, which serves to minimize the unnecessary electromagnetic wave radiation of the final product and maximize the immunity of the device to the unnecessary electromagnetic waves. However, as the operating frequency gradually moves toward the high frequency band, conventional nickel-zinc Ferrite (Ni-Zn Ferrite), manganese-zinc Ferrite (Mn-Zn Ferrite), sendust (Sendust) and other materials are unsuitable for electromagnetic shielding and absorbing materials in the several GHz to tens of GHz bands due to their low magnetic anisotropy in their crystal structures. Currently, with the advent of fifth-generation wireless communication (5G), the necessity of electromagnetic wave absorbing materials for the 3.5GHz and 28GHz bands is increasing, with the necessity of absorbing materials for the 28GHz band particularly rising, but the supply of suitable materials is insufficient. Prior art literature Korean registered patent No. 10-2621490 Disclosure of Invention Problems to be solved by the invention The present invention aims to provide a method for producing an electromagnetic wave absorbing material for the Ka band (26.5 GHz to 40 GHz) in the 5G communication field, the material comprising a W-type hexaferrite (W-type hexaferrite) containing no or only a very small amount of Fe 2+ ions. The technical problems to be solved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned can be clearly understood by those skilled in the art to which the present invention pertains from the following description. Means for solving the problems In order to achieve the above technical object, one embodiment of the present invention provides a method for producing an electromagnetic wave absorbing material. According to one embodiment of the present invention, a method for manufacturing an electromagnetic wave absorbing material includes a step of mixing powder including at least one selected from the group consisting of a Ca precursor, a Ba precursor, a Sr precursor, a Re precursor, a Me precursor, a Co precursor, and an Fe precursor, a step of performing a first heat treatment on the mixed powder, a step of ball-milling the heat-treated powder, and a step of performing a second heat treatment on the ball-milled powder, thereby manufacturing an electromagnetic wave absorbing mate