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CN-122012969-A - Mg/MgO magnesium-based composite material with gradient impedance structure, and preparation method and application thereof

CN122012969ACN 122012969 ACN122012969 ACN 122012969ACN-122012969-A

Abstract

The invention discloses an Mg/MgO magnesium matrix composite material with a gradient impedance structure, and a preparation method and application thereof, and relates to the technical field of electromagnetic shielding materials. The preparation method specifically comprises the steps of taking magnesium powder under an inert atmosphere, performing ball milling treatment for different times to respectively obtain magnesium powder with different oxygen contents, paving the magnesium powder with different oxygen contents in a reaction device according to the sequence of short ball milling treatment time to long ball milling treatment time under the inert atmosphere, performing vacuum hot-pressing sintering on the reaction device, and cooling to obtain the Mg/MgO magnesium-based composite material with the gradient impedance structure. According to the invention, through the synergistic effect of gradient impedance design and hot-pressing sintering, the electromagnetic wave reflection on the surface of the material is obviously reduced, and the electromagnetic wave absorption efficiency is enhanced. The electromagnetic shielding effectiveness of the prepared composite material in the X wave band is obviously improved, the efficient electromagnetic shielding taking absorption as a main effect is realized, and the secondary electromagnetic pollution is effectively reduced.

Inventors

  • XU ZUNYAN
  • LI KEHAO
  • PAN JUNWEN
  • YAO WENBO
  • LI CAIJU
  • YI JIANHONG

Assignees

  • 昆明理工大学

Dates

Publication Date
20260512
Application Date
20260121

Claims (7)

  1. 1. The preparation method of the Mg/MgO magnesium-based composite material with the gradient impedance structure is characterized by comprising the following steps of: (1) Powder pretreatment, namely taking magnesium powder under inert atmosphere, and performing ball milling treatment for different times to obtain magnesium powder with different oxygen contents respectively; (2) Paving the magnesium powder with different oxygen contents obtained in the step (1) in the order from short to long in ball milling treatment time under inert atmosphere; (3) And (3) sintering and forming, namely performing vacuum hot-pressing sintering on the reaction device in the step (2), and cooling to obtain the Mg/MgO magnesium-based composite material with the gradient impedance structure along the thickness direction.
  2. 2. The method for preparing the Mg/MgO magnesium matrix composite having the gradient impedance structure according to claim 1, wherein the ball milling time of the magnesium powder in the step (1) is t, t+n, t+2n, t+3n, wherein n is 4 and t is 2h, respectively.
  3. 3. The method for preparing the Mg/MgO magnesium-based composite material with the gradient impedance structure according to claim 1, wherein the ball milling condition in the step (1) is ball milling under the conditions that the ball material ratio is 5:1, the ball milling rotating speed is 150rpm and the vacuum degree is 5-10 Pa.
  4. 4. The preparation method of the Mg/MgO magnesium-based composite material with the gradient impedance structure, which is disclosed in claim 1, is characterized in that the thickness of each magnesium powder pavement layer in the step (2) is 2mm, and the number of pavement layers of the magnesium powder is 6.
  5. 5. The method for preparing the Mg/MgO magnesium-based composite material with the gradient impedance structure according to claim 1, wherein the condition of vacuum hot-pressing sintering in the step (3) is that sintering is carried out for 3 hours under the conditions that the vacuum degree is 5-10Pa, the sintering pressure is 30-70MPa and the sintering temperature is 580-620 ℃.
  6. 6. The Mg/MgO magnesium-based composite material with the gradient impedance structure, which is prepared by the method of any one of claims 1-5.
  7. 7. The use of the Mg/MgO Mg matrix composite having a gradient resistance structure as claimed in claim 6 in the field of electromagnetic interference shielding.

Description

Mg/MgO magnesium-based composite material with gradient impedance structure, and preparation method and application thereof Technical Field The invention relates to an Mg/MgO magnesium matrix composite material with a gradient impedance structure, and a preparation method and application thereof, and belongs to the technical field of electromagnetic shielding materials. Background With the rapid development of 5G communication technology, electromagnetic pollution and electromagnetic interference between devices are increasingly serious. Magnesium and its alloys are regarded as ideal structure-function integrated materials because of their high specific strength and inherent electromagnetic shielding properties, and have wide application prospects in the fields of portable electronic devices and communications. Traditional metallic electromagnetic shielding materials mainly rely on strong skin effects induced by high conductivity to reflect electromagnetic waves. However, this reflection-dominant shielding mechanism is prone to secondary electromagnetic contamination. Current research to improve the barrier properties of magnesium-based materials has focused on improving their electrical conductivity through alloying, heat treatment or texture control, but this often contradicts strategies to improve the mechanical strength of the material (e.g., introducing lattice defects), resulting in a mismatch in "strength-barrier" properties. In recent years, the related art introduces a second phase (e.g., metal particles, carbon materials, ferrite) in a magnesium matrix to increase interfacial polarization, enhancing electromagnetic wave absorption. But due to the strong skin effect of metallic materials, the reflection loss (SE R) is still generally higher than the absorption loss (SE A). The layered structure and the gradient impedance design prove that the impedance matching of the material and the free space can be effectively regulated, the surface reflection is reduced, and the electromagnetic wave is promoted to enter the material and be absorbed. However, how to realize a controllable gradient impedance structure in a magnesium-based composite material, and thereby obtain an electromagnetic shielding material with high absorption performance, has yet to be studied intensively. Disclosure of Invention Aiming at the defects of the related technology, the invention provides an Mg/MgO magnesium-based composite material with a gradient impedance structure, a preparation method and application thereof, the method realizes the gradient change of the internal impedance of the material through a simple and controllable process, the composite material has high-efficiency electromagnetic shielding performance taking absorption as a main factor, and solves the problem of realizing controllable gradient impedance structure construction in the magnesium-based composite material and obtaining the electromagnetic shielding material with high absorption performance. The invention aims to provide a preparation method of an Mg/MgO magnesium-based composite material with a gradient impedance structure, which comprises the following steps: (1) And (3) powder pretreatment, namely taking magnesium powder under an inert atmosphere (preferably argon atmosphere), and performing ball milling treatment for different times to obtain magnesium powder with different oxygen contents. (2) And (3) paving the magnesium powder with different oxygen contents obtained in the step (1) in the reaction device (preferably a hot-pressing die is used as the reaction device) in the order from short to long in ball milling treatment time under an inert atmosphere (preferably an argon atmosphere). (3) And (3) sintering and forming, namely performing vacuum hot-pressing sintering on the reaction device in the step (2), and cooling to obtain the Mg/MgO magnesium-based composite material with the gradient impedance structure along the thickness direction. Preferably, the ball milling time of the magnesium powder in the step (1) is t, t+n, t+2n, t+3n. Preferably, the ball milling condition in the step (1) is that ball milling is carried out under the conditions that the ball material ratio is 5:1, the ball milling rotating speed is 150rpm and the vacuum degree is 5-10 Pa. More preferably, the purity of the magnesium powder in the step (1) is 99.9%. Preferably, the thickness of each layer of magnesium powder paved in the step (2) is 2mm, and the paving layers of the magnesium powder are 6 layers. Preferably, the condition of vacuum hot-pressing sintering in the step (3) is that sintering is carried out for 3 hours under the conditions that the vacuum degree is 5-10Pa, the sintering pressure is 30-70MPa and the sintering temperature is 580-620 ℃. The second purpose of the invention is to provide the Mg/MgO magnesium-based composite material with the gradient impedance structure, which is prepared by adopting the preparation method of the invention. The invent