CN108393487B - Negative dielectric material based on metal powder insulation coating and preparation method thereof - Google Patents

Negative dielectric material based on metal powder insulation coating and preparation method thereof Download PDF

Info

Publication number
CN108393487B
CN108393487B CN201810575436.1A CN201810575436A CN108393487B CN 108393487 B CN108393487 B CN 108393487B CN 201810575436 A CN201810575436 A CN 201810575436A CN 108393487 B CN108393487 B CN 108393487B
Authority
CN
China
Prior art keywords
metal powder
negative dielectric
dielectric material
powder
material based
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN201810575436.1A
Other languages
Chinese (zh)
Other versions
CN108393487A (en
Inventor
范润华
解培涛
刘峣
张子栋
孙凯
信家豪
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shandong University
Shanghai Maritime University
Original Assignee
Shandong University
Shanghai Maritime University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shandong University, Shanghai Maritime University filed Critical Shandong University
Priority to CN201810575436.1A priority Critical patent/CN108393487B/en
Publication of CN108393487A publication Critical patent/CN108393487A/en
Application granted granted Critical
Publication of CN108393487B publication Critical patent/CN108393487B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/16—Metallic particles coated with a non-metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/10—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
    • B22F1/102—Metallic powder coated with organic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Powder Metallurgy (AREA)
  • Organic Insulating Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

The invention discloses a negative dielectric material based on metal powder insulation coating and a preparation method thereof, wherein the method comprises the following steps: step 1: preparing metal powder coated with silicon dioxide in an insulating way; step 2: insulating and coating metal powder and untreated metal powder according to the weight ratio of 0-1.5: 1 to obtain mixed metal powder; and step 3: mixing the mixed metal powder with the epoxy resin powder according to the proportion of 1-4: 1 to obtain composite powder; and 4, step 4: and processing and molding the composite powder to obtain the negative dielectric material based on metal powder insulation coating. The negative dielectric constant of the negative dielectric material based on the metal powder insulation coating prepared by the invention is adjustable in a frequency band of 10MHz-1GHz, and the size of the negative dielectric constant can be accurately adjusted and controlled in a range of-2000 to 0. The regulation and control method mainly comprises the steps of regulating and controlling the proportion of the metal powder coated in the insulating mode to the metal powder not coated and the proportion of the metal powder to the epoxy resin, and being simple to operate and low in cost.

Description

Negative dielectric material based on metal powder insulation coating and preparation method thereof
Technical Field
The invention relates to the field of material preparation, in particular to a negative dielectric material based on metal powder insulation coating and a preparation method thereof.
Background
The dielectric constant is a fundamental electrical parameter of a dielectric. Generally, the dielectric constant is positive and is a function of frequency, and there are different polarization mechanisms, such as ion polarization, electron polarization, space charge polarization, etc., in different frequency bands. That is, the positive dielectric constant results from the short range motion of the charge, which is also referred to as an electric dipole. However, some materials or states have negative dielectric constants, such as semiconductors and metals in the infrared band. Although radio communication benefits from the negative dielectric properties of the atmospheric ionosphere, negative dielectric properties have not attracted much attention until the advent of metamaterials. The negative dielectric metamaterial has wide market application prospect, for example, the negative dielectric metamaterial can be combined with a medicament to realize biological monitoring, can be used as a part of a waveguide cavity to realize tunneling of electromagnetic waves, can be compounded with a positive dielectric material to realize high dielectric property, and can also be used as an electromagnetic shielding material. The negative dielectric properties of a metamaterial are also referred to as artificial properties because it originates from artificial building blocks of the metamaterial rather than the material itself. Since then, negative dielectric properties also cause research hot flashes in metamaterials that do not contain artificial building blocks. These conventional materials, also known as intrinsic metamaterials or metameric composites, are often accompanied by percolation phenomena. In metal ceramic composite materials and polymer matrix composite materials, negative dielectric properties are widely researched, however, how to effectively regulate the negative dielectric properties is still a difficult problem, especially the precise control of the numerical value and the frequency band of the negative dielectric properties.
From literature studies, we can see that negative dielectric constant is derived from the oscillation of free electrons. That is, when the free electrons in the conductive seasoning generate simple harmonic motion, the directions of the polarization electric field and the external electric field in the material can be the same, so that the equivalent dielectric constant becomes a negative value. Because the negative permittivity arises analytically from the motion of the electrons, and not from the perspective of energy storage, the existence of a negative permittivity does not violate the law of conservation of energy. When considering the movement of electrons, it can be concluded that the length of the path through which the electrons can move has a large influence on the negative dielectric constant, although this length is difficult to define. When the motion path is short, it can be regarded as a dipole, and a positive dielectric is generated, and when the motion path is long, a simple harmonic motion is generated, and a negative dielectric is generated. Therefore, this phenomenon provides us with an effective control of the negative dielectric constant.
Disclosure of Invention
The invention aims to provide a negative dielectric material based on metal powder insulation coating and a preparation method thereof, so as to solve the problems of the prior art.
In order to achieve the purpose, the invention provides a preparation method of a negative dielectric material based on metal powder insulation coating, which comprises the following steps:
step 1: preparing metal powder coated with silicon dioxide in an insulating way;
step 2: insulating and coating metal powder and untreated metal powder according to the weight ratio of 0-1.5: 1 to obtain mixed metal powder;
and step 3: mixing the mixed metal powder with the epoxy resin powder according to the proportion of 1-4: 1 to obtain composite powder;
and 4, step 4: and processing and molding the composite powder to obtain the negative dielectric material based on metal powder insulation coating.
In the preparation method of the negative dielectric material based on the metal powder insulation coating, in the step 1, the silicon dioxide insulation coating of the metal powder is completed by utilizing the hydrolysis of the sodium silicate.
The preparation method of the negative dielectric material based on the metal powder insulation coating comprises the step of preparing a negative dielectric material based on the metal powder insulation coating, wherein the particle size of the metal powder is 1-200 mu m.
In the preparation method of the negative dielectric material based on the metal powder insulation coating, the epoxy resin is bisphenol a.
The preparation method of the negative dielectric material based on the metal powder insulation coating comprises the step of preparing the epoxy resin with the particle size of 1-5 mu m.
In the preparation method of the negative dielectric material based on the metal powder insulation coating, the step 2 and the step 3 are mixed in a ball milling mode.
In the preparation method of the negative dielectric material based on the metal powder insulation coating, in the step 4, the processing and molding manner is hot press molding.
The invention also provides the negative dielectric material based on the metal powder insulation coating, which is prepared by the preparation method of the negative dielectric material based on the metal powder insulation coating.
Compared with the prior art, the invention has the following beneficial effects:
the negative dielectric constant of the negative dielectric material based on the metal powder insulation coating prepared by the invention is adjustable in a frequency band of 10MHz-1GHz, and the size of the negative dielectric constant can be accurately adjusted and controlled in a range of-2000 to 0. The regulation and control method mainly comprises the steps of regulating and controlling the proportion of the metal powder coated in the insulating mode to the metal powder not coated and the proportion of the metal powder to the epoxy resin, and being simple to operate and low in cost.
Drawings
FIG. 1 is an SEM image of FeSiB metal amorphous powder used in example 1 of the present invention;
FIG. 2 is an SEM image of a metal powder insulation clad based negative dielectric material prepared in example 1 of the present invention;
FIG. 3 is a dielectric spectrum of the metal powder based insulation coated negative dielectric material prepared in example 1;
fig. 4 is a partially enlarged schematic view of fig. 3.
Detailed Description
The invention will be further described by the following specific examples in conjunction with the drawings, which are provided for illustration only and are not intended to limit the scope of the invention.
The invention provides a preparation method of a negative dielectric material based on metal powder insulation coating, which comprises the following steps:
step 1: preparing metal powder coated with silicon dioxide in an insulating way;
specifically, the method comprises the following steps: the particle size range of the metal powder used in the present invention is between 1 μm and 200 μm. Dispersing the metal powder raw material in ethylene glycol at a mass ratio of 1:50 (the ratio is the best effect), and ultrasonically dispersing for 60 min. The mixed solution was transferred to a constant temperature water bath kettle, stirred by mechanical force, 90 ℃. Both 1mol/L sodium silicate solution and 1mol/L sulfuric acid solution were added dropwise to the mixed solution at 200mL/h simultaneously. Stirring was maintained for 2 hours. Thus obtaining the metal powder coated with silicon dioxide in an insulating way.
Step 2: insulating and coating metal powder and untreated metal powder according to the weight ratio of 0-1.5: 1 to obtain mixed metal powder;
specifically, the method comprises the following steps: the metal powder coated in an insulating way and the untreated metal powder are mixed according to the weight ratio of 0-1.5: 1 in mass ratio. The mixing method is ball milling and dry milling. When a planetary ball mill is used for mixing, the total ball-material ratio is 1-2, the ball milling rotating speed is 100r/min-260/min, and the ball milling time is 10-20 min; when a vibration ball mill is used for mixing materials, the ball-material ratio is 1-2, low-frequency vibration is firstly carried out for 15 seconds, then high-frequency vibration is carried out for 20-40 seconds, and circulation is carried out for 1-3 times.
And step 3: mixing the mixed metal powder with the epoxy resin powder according to the proportion of 1-4: 1 to obtain composite powder;
specifically, the method comprises the following steps: the epoxy resin is bisphenol A type, and the particle size is 1-5 μm. The mass ratio of the mixed metal powder to the epoxy resin powder is 1-4: 1. the mixing method is ball milling and dry milling. When a planetary ball mill is used for mixing, the total ball-material ratio is 2 (the optimal ratio), the ball milling rotating speed is 260r/min, and the ball milling time is 1-2 hours; when a vibration ball mill is used for mixing materials, the ball-material ratio is 1-3, low-frequency vibration is performed for 12-25 seconds, then high-frequency vibration is performed for 90-120 seconds, and circulation is performed for 3-6 times.
And 4, step 4: processing and molding the composite powder to obtain a negative dielectric material based on metal powder insulation coating;
specifically, the method comprises the following steps: the size of the mould is designed according to the size of the material to be prepared. The forming mode is hot press forming. The powder is poured into a mould and preheated for 20-40min at 60-140 ℃. And then pressurized. During pressurization, the pressure is maintained for 3-10min under the pressure of 20 MPa; and then maintaining the pressure at 30MPa, no heating at this time, releasing the pressure when cooling to room temperature, wherein the pressure release rate is 5MPa/min-30MPa/min, and the cooling mode can be natural cooling or circulating water cooling.
The invention also provides the negative dielectric material based on the metal powder insulation coating, which is prepared by the preparation method of the negative dielectric material based on the metal powder insulation coating.
Materials, reagents and the like used in the following examples are commercially available. Wherein the diameter of the FeSiB metal powder is about 100 μm; the epoxy resin powder is bisphenol A type, and the particle size is 1-5 μm.
Example 1:
a preparation method of a negative dielectric material based on metal powder insulation coating comprises the following steps:
step 1: silica insulated coated Fe78Si9B13(FeSiB) amorphous powder. The metal powder used in this example was FeSiB metal amorphous powder with a particle size of about 100 μm, see fig. 1. Dispersing FeSiB powder in ethylene glycol at a mass ratio of 1:50, and ultrasonically dispersing for 60 min. The mixed solution was transferred to a constant temperature water bath kettle, stirred by mechanical force, 90 ℃. Both 1mol/L sodium silicate solution and 1mol/L sulfuric acid solution were added dropwise to the mixed solution at 200mL/h simultaneously. Stirring was maintained for 2 hours. And obtaining the silicon dioxide insulated and coated FeSiB powder.
Step 2: the untreated FeSiB powder and the insulating coating powder were mixed in different ratios. Two kinds of metal powder are weighed, and the ratio is 7:3, 8:2, 8.5:1.5, 9:1, 9.5:0.5 and 10:0 in sequence. Mixing materials by using a vibration ball mill, wherein the ball material ratio is 2, firstly vibrating for 15 seconds at low frequency, then vibrating for 20 seconds at high frequency, and circulating for 2 times.
And step 3: mixing the mixed metal powder and the epoxy resin powder in a certain proportion. The mass ratio of the mixed metal powder to the epoxy resin powder is 6: 4. Mixing materials by using a vibration ball mill, wherein the ball material ratio is 2, firstly vibrating for 20 seconds at low frequency, then vibrating for 90 seconds at high frequency, and circulating for 4 times.
And 4, step 4: and (3) forming the mixed powder into a composite material with a certain shape. The die size was a circular disc with a diameter of 20mm and a thickness of 2 mm. The forming mode is hot press forming. The powder is poured into a mould and preheated for 30min at 80 ℃. And then pressurized. During pressurization, the pressure is maintained for 5min under the pressure of 20 MPa; and then maintaining the pressure at 30MPa, no heating at this time, naturally cooling to room temperature, and relieving the pressure at the pressure relief rate of 5 MPa/min. The microstructure of the negative dielectric material based on the metal powder insulation coating prepared in this example is shown in fig. 2. The negative dielectric properties are shown in FIGS. 3 and 4, in which (FeSiB)xcoated-FeSiB1-x)0.6Epoxy0.4An expression for the prepared negative dielectric material based on the insulating coating of metal powder, wherein FeSiBxcoated is silicon dioxide insulated coated FeSiB powder, FeSiB1-xThe powder is untreated FeSiB powder, Epoxy is Epoxy resin powder, and in the embodiment, x is 0.7, 0.8, 0.85, 0.9, 0.95 and 1, as can be seen from figures 3 and 4, the negative electrode based on the metal powder insulation coating prepared by the inventionThe negative dielectric constant of the dielectric material can be adjusted in a frequency band of 10MHz-1GHz, and the size of the negative dielectric constant can be accurately adjusted and controlled in a range of-2000 to 0.
Example 2:
a preparation method of a negative dielectric material based on metal powder insulation coating comprises the following steps:
step 1: and the silicon dioxide is insulated and coated with Fe powder. The metal powder used in this example was Fe powder, and had a particle size of about 120 μm. Dispersing Fe powder in ethylene glycol at a mass ratio of 1:60, and performing ultrasonic dispersion for 60 min. The mixed solution was transferred to a constant temperature water bath kettle, stirred by mechanical force, 90 ℃. Both 1mol/L sodium silicate solution and 1mol/L sulfuric acid solution were added dropwise to the mixed solution at 200mL/h simultaneously. Stirring was maintained for 2 hours. And obtaining the silicon dioxide insulation coated Fe powder.
Step 2: untreated Fe powder and insulating coating powder were mixed in different proportions. Two kinds of metal powder are weighed, and the ratio is 7:3, 8:2, 8.5:1.5, 9:1, 9.5:0.5 and 10:0 in sequence. Mixing materials by using a vibration ball mill, wherein the ball material ratio is 2, firstly vibrating for 15 seconds at low frequency, then vibrating for 20 seconds at high frequency, and circulating for 2 times.
And step 3: mixing the mixed metal powder and the epoxy resin powder in a certain proportion. The mass ratio of the mixed metal powder to the epoxy resin powder is 7: 3. Mixing materials by using a vibration ball mill, wherein the ball material ratio is 2, firstly vibrating for 20 seconds at low frequency, then vibrating for 90 seconds at high frequency, and circulating for 4 times.
And 4, step 4: and (3) forming the mixed powder into a composite material with a certain shape. The die size was a circular disc with a diameter of 20mm and a thickness of 2 mm. The forming mode is hot press forming. The powder is poured into a mould and preheated for 30min at 100 ℃. And then pressurized. During pressurization, the pressure is maintained for 5min under the pressure of 20 MPa; and then maintaining the pressure at 40MPa, no heating at this time, naturally cooling to room temperature, and relieving the pressure at the pressure relief rate of 5 MPa/min.
Example 3:
a preparation method of a negative dielectric material based on metal powder insulation coating comprises the following steps:
step 1: and silicon dioxide is coated with Cu powder in an insulating way. The metal powder used in this example was Cu powder, and had a particle size of about 20 μm. Dispersing Cu powder in ethylene glycol at a mass ratio of 1:40, and performing ultrasonic dispersion for 60 min. The mixed solution was transferred to a constant temperature water bath kettle, stirred by mechanical force, 90 ℃. Both 1mol/L sodium silicate solution and 1mol/L sulfuric acid solution were added dropwise to the mixed solution at 200mL/h simultaneously. Stirring was maintained for 2 hours. And obtaining the silicon dioxide insulation coated Cu powder.
Step 2: the untreated Cu powder and the insulating coated powder were mixed in different ratios. Two kinds of metal powder are weighed, and the ratio is 7:3, 8:2, 8.5:1.5, 9:1, 9.5:0.5 and 10:0 in sequence. Mixing materials by using a vibration ball mill, wherein the ball material ratio is 2, firstly vibrating for 15 seconds at low frequency, then vibrating for 20 seconds at high frequency, and circulating for 2 times.
And step 3: mixing the mixed metal powder and the epoxy resin powder in a certain proportion. The mass ratio of the mixed metal powder to the epoxy resin powder is 8: 2. Mixing materials by using a vibration ball mill, wherein the ball material ratio is 2, firstly vibrating for 20 seconds at low frequency, then vibrating for 90 seconds at high frequency, and circulating for 4 times.
And 4, step 4: and (3) forming the mixed powder into a composite material with a certain shape. The die size was a circular disc with a diameter of 20mm and a thickness of 2 mm. The forming mode is hot press forming. The powder is poured into a mould and preheated for 30min at 90 ℃. And then pressurized. During pressurization, the pressure is maintained for 5min under the pressure of 20 MPa; and then maintaining the pressure at 40MPa, no heating at this time, naturally cooling to room temperature, and relieving the pressure at the pressure relief rate of 10 MPa/min.
In conclusion, the negative dielectric constant of the negative dielectric material based on the metal powder insulation coating prepared by the invention is adjustable in a frequency band of 10MHz-1GHz, and the size of the negative dielectric constant can be accurately adjusted and controlled in a range of-2000 to 0. The regulation and control method mainly comprises the steps of regulating and controlling the proportion of the metal powder coated in the insulating mode to the metal powder not coated and the proportion of the metal powder to the epoxy resin, and being simple to operate and low in cost.
While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.

Claims (8)

1. A preparation method of a negative dielectric material based on metal powder insulation coating is characterized by comprising the following steps:
step 1: preparing metal powder coated with silicon dioxide in an insulating way;
step 2: mixing the metal powder coated in an insulating way and the untreated metal powder according to the mass ratio of more than 0 and less than or equal to 1.5 to obtain mixed metal powder;
and step 3: mixing the mixed metal powder with the epoxy resin powder according to the proportion of 1-4: 1 to obtain composite powder;
and 4, step 4: and processing and molding the composite powder to obtain the negative dielectric material based on metal powder insulation coating.
2. The method of preparing a negative dielectric material based on insulating coating of metal powder as claimed in claim 1, wherein the silica insulating coating of metal powder is performed by hydrolysis of sodium silicate in step 1.
3. The method of claim 1, wherein the metal powder has a particle size of 1 μm to 200 μm.
4. The method of claim 1, wherein the epoxy resin is bisphenol a.
5. The method of claim 1, wherein the epoxy resin has a particle size of 1 μm to 5 μm.
6. The method according to claim 1, wherein the step 2 and the step 3 are performed by ball milling.
7. The method for preparing the negative dielectric material based on the insulating coating of the metal powder as claimed in claim 1, wherein in the step 4, the processing and forming manner is hot press forming.
8. The negative dielectric material based on metal powder insulation coating prepared by the preparation method of the negative dielectric material based on metal powder insulation coating according to any one of claims 1 to 7.
CN201810575436.1A 2018-06-06 2018-06-06 Negative dielectric material based on metal powder insulation coating and preparation method thereof Expired - Fee Related CN108393487B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810575436.1A CN108393487B (en) 2018-06-06 2018-06-06 Negative dielectric material based on metal powder insulation coating and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810575436.1A CN108393487B (en) 2018-06-06 2018-06-06 Negative dielectric material based on metal powder insulation coating and preparation method thereof

Publications (2)

Publication Number Publication Date
CN108393487A CN108393487A (en) 2018-08-14
CN108393487B true CN108393487B (en) 2020-10-30

Family

ID=63102746

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810575436.1A Expired - Fee Related CN108393487B (en) 2018-06-06 2018-06-06 Negative dielectric material based on metal powder insulation coating and preparation method thereof

Country Status (1)

Country Link
CN (1) CN108393487B (en)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7033523B2 (en) * 2003-11-14 2006-04-25 Photintech Inc. Composite liquid crystalline mixture
CN102012537A (en) * 2010-08-30 2011-04-13 南京大学 Optical waveguide utilizing artificial electromagnetic medium
CN103030728B (en) * 2011-09-06 2017-09-26 日立化成株式会社 Insulating wrapped particle, insulating wrapped conducting particles, anisotropic conductive material and connection structural bodies
CN103788520B (en) * 2013-06-28 2016-06-29 深圳光启创新技术有限公司 Absorbing meta-material and preparation method thereof
US9400412B2 (en) * 2014-07-16 2016-07-26 Kent State University Nanosecond liquid crystalline optical modulator
CN106711271B (en) * 2017-02-03 2019-09-06 江西师范大学 Three-band near-infrared absorber based on semiconductor super-surface structure

Also Published As

Publication number Publication date
CN108393487A (en) 2018-08-14

Similar Documents

Publication Publication Date Title
CN108987086B (en) Two-dimensional layered metal soft magnetic composite material and preparation method and application thereof
CN111739730B (en) Preparation method of organic-coated high-performance metal magnetic powder core
CN111889698A (en) Preparation method of superfine spherical silver powder
KR101458839B1 (en) Electric wave absorption sheet for near-field and manufacturing method thereof
CN107286907B (en) Molybdenum disulfide/carbonyl iron composite microwave absorbent with core-shell structure and preparation method thereof
CN110494030B (en) Preparation method of resin-reinforced ferrite solid waste based broadband electromagnetic wave absorber
CN108298973B (en) Graphene/ferrite-based passive frequency control material and preparation method thereof
CN108393487B (en) Negative dielectric material based on metal powder insulation coating and preparation method thereof
CN110872179B (en) Preparation method of flexible radio-frequency-band negative dielectric and negative magnetic conductivity wave-absorbing material
CN112624768B (en) Ceramic-based ternary composite material with weak negative dielectric property and preparation method thereof
CN106521312A (en) Method for preparing FeSiAl-series alloy micro powder electromagnetic absorbent
CN111944267B (en) Preparation method of boron-doped graphene composite material and application of boron-doped graphene composite material as negative dielectric material
CN113773069B (en) Ferrite material and preparation method and application thereof
CN110227396B (en) Preparation method of graphene/polyolefin elastomer microspheres with near-zero dielectric constant
JP4752027B2 (en) Electromagnetic wave absorption molding
CN112358711A (en) Magnetic-thermal coupling tunable wave-absorbing material and preparation method thereof
KR102011343B1 (en) Metal oxide / polymer composite having electromagnetic wave shielding ability in GHz band and electromagnetic wave shielding material manufactured using the same
CN113488330B (en) Preparation method of functional magnetic slurry and magnetic device
CN111234460B (en) Resin composition, wave-absorbing composite material prepared from composition and preparation method of wave-absorbing composite material
CN102838346A (en) Antenna substrate material using spinel ferrite as matrix and preparation method thereof
CN113059834A (en) Preparation method of pearl shell-imitated electromagnetic wave absorption film
CN110526701A (en) A kind of method that ferrite solid waste cycling and reutilization prepares electromagnetic wave absorbent material
CN103700481A (en) High-performance nanocrystalline magnetic core preparation method for high-frequency electronic transformer
CN115746787B (en) Composite wave-absorbing material, preparation method and application
CN108773858A (en) A kind of pattern-band Surface Wave Absorbing Material and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20201030

Termination date: 20210606

CF01 Termination of patent right due to non-payment of annual fee