CN111892093A - Microwave absorbing material and preparation method thereof - Google Patents
Microwave absorbing material and preparation method thereof Download PDFInfo
- Publication number
- CN111892093A CN111892093A CN202010805822.2A CN202010805822A CN111892093A CN 111892093 A CN111892093 A CN 111892093A CN 202010805822 A CN202010805822 A CN 202010805822A CN 111892093 A CN111892093 A CN 111892093A
- Authority
- CN
- China
- Prior art keywords
- absorbing material
- microwave absorbing
- nitrate
- citric acid
- feo
- 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.)
- Granted
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/009—Compounds containing, besides iron, two or more other elements, with the exception of oxygen or hydrogen
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/42—Magnetic properties
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The invention provides a microwave absorbing material, the molecular formula of which is Bi(0～0.3)La(0.7～1)FeO3. The microwave absorbing material provided by the invention has multiple polarizations, including space charge polarization, dipole polarization and interface polarization, so that the dielectric loss of the material is reduced, meanwhile, a large number of irregular micropores are formed in the material, the pore size distribution is narrow, multiple reflection channels exist, when electromagnetic waves are emitted into the material, the electromagnetic waves are reflected and scattered for multiple times in the material, so that the electromagnetic waves are attenuated more, and the purpose of reducing the thickness of the material and realizing excellent wave absorption performance is achieved. Experimental results show that the microwave absorbing material provided by the invention can absorb electromagnetic waves in a 2-18 GHz microwave band, the absorption efficiency is more than 90%, and the microwave absorbing material can obtain excellent microwave absorbing performance within the thickness of 1.6-2.0 mm.
Description
Technical Field
The invention relates to the technical field of materials, in particular to a microwave absorbing material and a preparation method thereof.
Background
With the development of communication technology, 5G technology will be a trend of development. When a 5G signal base station is constructed, high-frequency electromagnetic equipment has large energy output during working, the formed high-frequency electromagnetic radiation is strong, and great interference is generated on other electronic equipment and communication facilities, so that the daily life of people is seriously influenced, and the health of human is harmed. Therefore, it is necessary to load microwave absorbing materials on the surface of the equipment to reduce the influence of electromagnetic waves on the environment and human body.
The existing microwave absorbing materials mainly comprise alloy micro powder, ferrite, rare earth oxide, rubber-based composite materials and the like. Wherein the rare earth oxide is widely applied by virtue of excellent wave-absorbing performance. For example "Bi1-xLaxFeO3Bi has been studied in the microwave absorption properties of the multiferroic system (Zhongnan university newspaper, vol 42, No 11, Zhao News, 2011)1-xLaxFeO3The microwave electromagnetic response characteristic of the powder crystal in the frequency range of 2-18 GHz shows that when the thickness of the sample is 2.6mm and x is 0.1, the effective absorption bandwidth of the sample reaches 3.4GHz above 10dB, and the absorption peak reaches 27.7 dB. Although the research improves the wave absorbing performance of the microwave absorbing material, the coating is thicker, and the production cost is greatly increased. With the rapid development of the microwave absorption field, the requirement for the thickness of the microwave absorption material coating is higher and higher. Therefore, there is a need for further improvements in microwave absorbing materials that ensure their excellent wave absorbing properties while reducing their thickness and hence cost.
Disclosure of Invention
The invention aims to provide a microwave absorbing material and a preparation method thereof. The microwave absorbing material provided by the invention is thin in coating thickness and has excellent wave absorbing performance.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a microwave absorbing material, the molecular formula of which is Bi(0～0.3)La(0.7～1)FeO3。
Preferably, the molecular formula of the microwave absorbing material is Bi(0.1～0.3)La(0.7～0.9)FeO3。
Preferably, the molecular formula of the microwave absorbing material is Bi(0.2～0.3)La(0.7～0.8)FeO3。
The invention also provides a preparation method of the microwave absorbing material in the technical scheme, which comprises the following steps:
(1) mixing metal nitrate with citric acid solution, and carrying out gelation reaction to obtain gel; the metal nitrate comprises three types of bismuth nitrate, lanthanum nitrate and ferric nitrate, or two types of lanthanum nitrate and ferric nitrate;
(2) and (2) drying, ashing and calcining the gel obtained in the step (1) in sequence to obtain the microwave absorbing material.
Preferably, the ratio of the amount of metal ions in the metal nitrate salt to the amount of citric acid in the citric acid solution in step (1) is 1: (1-2).
Preferably, the mass concentration of the citric acid solution in the step (1) is 15.8-16.1%.
Preferably, the temperature of the gelation reaction in the step (1) is 80-100 ℃, and the time of the gelation reaction is 3-4.5 h.
Preferably, the drying temperature in the step (2) is 80-100 ℃, and the drying time is 20-36 h.
Preferably, the ashing temperature in the step (2) is 200-300 ℃, and the ashing time is 5-10 min.
Preferably, the calcining temperature in the step (2) is 600-700 ℃, and the calcining time is 5-10 h.
The invention provides a microwave absorbing material, the molecular formula of which is Bi(0～0.3)La(0.7～1)FeO3. The microwave absorbing material provided by the invention has multiple polarizations including space charge polarization, dipole polarization and interface polarization, reduces the dielectric loss of the material, has a large number of irregular micropores in the material, has narrow pore size distribution and multiple reflection channels, and when electromagnetic waves are emitted into the material, the electromagnetic waves are reflected and scattered for multiple times in the material to cause larger attenuation of the electromagnetic waves, thereby achieving the purpose of reducing the thickness of the material and also reducing the thickness of the materialThe purpose of excellent wave absorption performance can be achieved. Experimental results show that the microwave absorbing material provided by the invention can absorb electromagnetic waves in a 2-18 GHz microwave band, the absorption efficiency is more than 90%, and the microwave absorbing material can obtain excellent microwave absorbing performance within the thickness of 1.6-2.0 mm.
Drawings
FIG. 1 is an XRD spectrum of a microwave absorbing material prepared in examples 1 to 4;
FIG. 2 shows Bi prepared in examples 1 to 4(0～0.3)La(0.7～1)FeO3A reflectivity loss plot for a microwave absorbing material having a thickness of 2 mm;
FIG. 3 shows LaFeO prepared in example 13A reflectance loss plot of the microwave absorbing material;
FIG. 4 shows Bi prepared in example 20.1La0.9FeO3A reflectance loss plot of the microwave absorbing material;
FIG. 5 shows Bi prepared in example 30.2La0.8FeO3A reflectance loss plot of the microwave absorbing material;
FIG. 6 shows Bi prepared in example 40.3La0.7FeO3Reflectance loss plot of microwave absorbing material.
Detailed Description
The invention provides a microwave absorbing material, the molecular formula of which is Bi(0～0.3)La(0.7～1)FeO3Further preferably Bi(0.1～0.3)La(0.7～0.9)FeO3More preferably Bi(0.2～0.3)La(0.7～0.8)FeO3Most preferably Bi0.3La0.7FeO3. In the present invention, the microwave absorbing material Bi(0～0.3)La(0.7～1)FeO3There are multiple polarizations including space charge polarization (a microwave absorbing material has a large number of gaps and cavities, which are used as polarization centers to generate space charge polarization), dipole polarization (an increase in Bi doping amount causes an increase in lattice defects inside the microwave absorbing material, and a increase in dipoles inside the material causes an increase in dipole polarization), and interface polarization (a microwave absorbing material is mixed with paraffin to prepare the material)After the composite material is prepared, multiple phases exist in the composite material, when electromagnetic waves enter the material, charge accumulation can be generated between the phase interfaces, interface polarization is generated, the dielectric loss of the material is reduced, meanwhile, a large number of irregular micropores exist in the material, the pore size distribution is narrow, multiple reflection channels exist, the electromagnetic waves are reflected and scattered for multiple times after entering the material, the electromagnetic waves are attenuated to a greater extent, and the purpose that the thickness of the material is reduced and the excellent wave absorption performance can be achieved is achieved.
In the present invention, when the microwave absorbing material contains Bi, Bi is used3+Rare earth element La substituted for A site3 +Leading the crystal structure to change, leading the Fe-O-Fe bond angle to generate spin inclination, changing the dielectric constant of the wave-absorbing material, leading the imaginary part of the complex dielectric constant to increase, leading the dielectric loss to microwave to increase, increasing the natural resonance absorption peak by doping Bi element, simultaneously moving the absorption peak to the low-frequency area, leading the generation of oxygen vacancy, in order to ensure the charge conservation, Fe2+With Fe3+The electronic transition between the two is intensified, the conductivity of the material is increased, the real part of the dielectric constant is enhanced, and the wave absorbing performance of the microwave absorbing material is further improved.
The microwave absorbing material provided by the invention absorbs electromagnetic waves in a 2-18 GHz wave band, and a wave absorbing peak shows a double-peak trend along with the change of frequency, shows a stronger broadband characteristic, and has certain stability and stronger oxidation resistance.
The invention also provides a preparation method of the microwave absorbing material in the technical scheme, which comprises the following steps:
(1) mixing metal nitrate with citric acid solution, and carrying out gelation reaction to obtain gel; the metal nitrate comprises bismuth nitrate, lanthanum nitrate and ferric nitrate or lanthanum nitrate and ferric nitrate;
(2) and (2) drying, ashing and calcining the gel obtained in the step (1) in sequence to obtain the microwave absorbing material.
Mixing metal nitrate with citric acid solution, and carrying out gelation reaction to obtain gel; the metal nitrate comprises three types of bismuth nitrate, lanthanum nitrate and ferric nitrate, or two types of lanthanum nitrate and ferric nitrate. In the present invention, the bismuth nitrate is preferably bismuth nitrate pentahydrate; the lanthanum nitrate is preferably lanthanum nitrate hexahydrate, and the ferric nitrate is preferably ferric nitrate nonahydrate. In the present invention, the purity of the metal nitrate is preferably 99.9% or more. The source of the metal nitrate is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used. In the present invention, when the metal nitrate is bismuth nitrate, lanthanum nitrate, and iron nitrate, the ratio of the amounts of the bismuth nitrate, lanthanum nitrate, and iron nitrate is preferably (0 to 0.3): (0.7-1): 1, more preferably (0.2 to 0.25): (0.8-0.85): 1; when the metal nitrate is lanthanum nitrate and ferric nitrate, the ratio of the amount of the lanthanum nitrate to the amount of the ferric nitrate is preferably (0.7-1): 1, more preferably (0.8 to 0.85): 1. in the invention, the metal nitrate can be completely decomposed by heating, impurities are not introduced during the subsequent high-temperature treatment of the sol-gel method, and an oxidizing atmosphere can be provided.
In the present invention, the mass concentration of the citric acid solution is preferably 15.8% to 16.1%, and more preferably 15.9% to 16.0%. In the present invention, the citric acid solution is preferably obtained by mixing citric acid and distilled water. The operation of mixing the citric acid and the distilled water is not particularly limited in the invention, and the technical scheme for preparing the mixed material which is well known to the technical personnel in the field can be adopted. The source of each component in the citric acid solution is not particularly limited in the present invention, and commercially available products well known to those skilled in the art may be used. In the invention, the citric acid is used as a complexing agent, plays a role of complexing metal ions and can ensure the generation of gel.
In the present invention, the ratio of the amount of metal ions in the metal nitrate to the amount of citric acid in the citric acid solution is preferably 1: (1-2), more preferably 1: (1-1.5). In the present invention, the cost can be reduced when the ratio of the amount of the metal ions in the metal nitrate to the amount of the substance of citric acid in the citric acid solution is within the above range.
The operation of mixing the metal nitrate and the citric acid solution is not particularly limited in the invention, and the technical scheme for preparing the mixed material, which is well known to those skilled in the art, can be adopted.
In the invention, the temperature of the gelation reaction is preferably 80-100 ℃, and more preferably 80-90 ℃; the time of the gelation reaction is preferably 3 to 4.5 hours, and more preferably 3.5 to 4 hours. In the present invention, the gelation reaction is preferably carried out under stirring. In the invention, the rotation speed of the stirring is preferably 200-250 r/min. In the present invention, the gelation reaction is preferably carried out in a constant temperature water bath. The type of the constant-temperature water bath kettle is not specially limited, and instruments and equipment well known by the technical personnel in the field can be adopted. In the invention, the metal nitrate and the citric acid solution are mixed, and in the gelation reaction process, the metal nitrate forms red viscous gel through hydrogen bonds under the complexation of citric acid, so that the gel is obtained.
After the gel is obtained, the microwave absorbing material is obtained by sequentially drying, ashing and calcining the gel. In the invention, the drying temperature is preferably 80-100 ℃; the drying time is preferably 20-36 h. The drying operation is not particularly limited in the present invention, and a drying operation known to those skilled in the art may be employed.
In the invention, the ashing temperature is preferably 200-300 ℃, and more preferably 250-300 ℃; the time for ashing is preferably 5-10 min. In the present invention, the ashing is preferably performed in an electron oven. The type of the electronic oven is not particularly limited in the present invention, and the electronic oven can be made by using instruments and equipment well known to those skilled in the art. In the present invention, the ashing can be used to remove organic substances and impurities in the gel before calcination.
In the invention, the calcining temperature is preferably 600-700 ℃, and more preferably 650-700 ℃; the calcination time is preferably 5-10 h. In the present invention, the calcination is preferably carried out in a muffle furnace. The muffle furnace is not particularly limited in type, and instruments and equipment well known to those skilled in the art can be adopted. In the present invention, the calcination temperature can be in the above rangePure LaFeO can be obtained3Phase, and can effectively prevent the increase of Bi volatilization quantity, so that the Bi element enters LaFeO3Lattice, forming a solid solution.
The preparation method of the microwave absorbing material provided by the invention can obtain the wave absorbing material through gelation reaction, drying, ashing and calcining, has a simple preparation process, and is suitable for batch production.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Step (1), according to the molecular formula LaFeO35.35g of lanthanum nitrate hexahydrate and 4.99g of ferric nitrate nonahydrate (the mass ratio of lanthanum nitrate hexahydrate to ferric nitrate nonahydrate is 1: 1) with the purity of more than or equal to 99.9 percent are weighed, and the molar ratio of metal ions (lanthanum ions and iron ions) to citric acid is 1:1, weighing 5.21g of citric acid, mixing the citric acid with distilled water to obtain a citric acid solution (the mass concentration of the citric acid solution is 16.1%), then adding lanthanum nitrate and ferric nitrate into the citric acid solution for mixing, putting the obtained solution into a water bath kettle, continuously stirring at constant temperature and magnetic force (the stirring speed is 250r/min) at 80 ℃, and carrying out gelation reaction for 3 hours to obtain gel;
and (2) drying the gel obtained in the step (1) in a forced air drying oven at 80 ℃ for 20h, ashing the obtained dried substance at 300 ℃ for 5min, putting the treated dried substance into a muffle furnace, and calcining the dried substance at 700 ℃ in an air atmosphere for 10h to obtain a microwave absorbing material, namely LaFeO3。
Example 2
Step (1), Bi0.1La0.9FeO30.72g of bismuth nitrate pentahydrate, 4.81g of lanthanum nitrate hexahydrate and 4.99g of ferric nitrate nonahydrate (of bismuth nitrate pentahydrate, lanthanum nitrate hexahydrate and ferric nitrate nonahydrate) with purity of not less than 99.9% are weighedThe ratio of the amounts of substances is 0.1: 0.9: 1) then, 5.19g of citric acid is weighed according to the molar ratio of metal ions (lanthanum ions, iron ions and barium ions) to citric acid being 1:1, the citric acid and distilled water are mixed and magnetically stirred to obtain a citric acid solution (the mass concentration of the citric acid solution is 16%), then bismuth nitrate, lanthanum nitrate and ferric nitrate are added into the citric acid solution, the obtained solution is placed into a water bath kettle, and the gelling reaction is carried out for 3.5 hours under the condition of 80 ℃ and the continuous constant-temperature magnetic stirring (the stirring speed is 250r/min), so as to obtain gel;
and (2) drying the gel obtained in the step (1) in a forced air drying oven at 80 ℃ for 20h, ashing the obtained dried substance at 300 ℃ for 5min, putting the treated dried substance into a muffle furnace, and calcining the dried substance at 700 ℃ for 10h in an air atmosphere to obtain a microwave absorbing material, namely Bi0.1La0.9FeO3。
Example 3
Step (1) of preparing Bi according to the molecular formula0.2La0.8FeO3Weighing 1.32g of bismuth nitrate pentahydrate, 4.28g of lanthanum nitrate hexahydrate and 4.99g of ferric nitrate nonahydrate (the mass ratio of the substances of the bismuth nitrate pentahydrate, the lanthanum nitrate hexahydrate and the ferric nitrate nonahydrate is 0.2: 0.8: 1) with the purity of more than or equal to 99.9 percent, weighing 5.19g of citric acid according to the molar ratio of metal ions (lanthanum ions, iron ions and bismuth ions) to the citric acid of 1:1, mixing the citric acid with distilled water, carrying out magnetic stirring to obtain a citric acid solution (the mass concentration of the citric acid solution is 15.9 percent), then adding the bismuth nitrate, the lanthanum nitrate and the ferric nitrate into the citric acid solution, putting the obtained solution into a water bath, carrying out continuous constant-temperature magnetic stirring (the stirring speed is 250r/min) at the temperature of 80 ℃, and carrying out gelation reaction for 4 hours to obtain gel;
and (2) drying the gel obtained in the step (1) in a forced air drying oven at 80 ℃ for 20h, ashing the obtained dried substance at 300 ℃ for 5min, putting the treated dried substance into a muffle furnace, and calcining the dried substance at 700 ℃ for 10h in an air atmosphere to obtain a microwave absorbing material, namely Bi0.2La0.8FeO3。
Example 4
Step (1) of preparing Bi according to the molecular formula0.3La0.7FeO3Weighing 1.92g of bismuth nitrate pentahydrate, 3.74g of lanthanum nitrate hexahydrate and 4.99g of ferric nitrate nonahydrate (the mass ratio of the substances of the bismuth nitrate pentahydrate, the lanthanum nitrate hexahydrate and the ferric nitrate nonahydrate is 0.3: 0.7: 1) with the purity of more than or equal to 99.9 percent, weighing 5.19g of citric acid according to the molar ratio of metal ions (lanthanum ions, iron ions and bismuth ions) to the citric acid of 1:1, mixing the citric acid with distilled water and carrying out magnetic stirring to obtain a citric acid solution (the mass concentration of the citric acid solution is 15.8 percent), then adding the bismuth nitrate, the lanthanum nitrate and the ferric nitrate into the citric acid solution, putting the obtained solution into a water bath, carrying out continuous constant-temperature magnetic stirring (the stirring speed is 250r/min) at the temperature of 80 ℃, and carrying out gelation reaction for 4.5 hours to obtain gel;
and (2) drying the gel obtained in the step (1) in a forced air drying oven at 80 ℃ for 20h, ashing the obtained dried substance at 300 ℃ for 5min, putting the treated dried substance into a muffle furnace, and calcining the dried substance at 700 ℃ for 10h in an air atmosphere to obtain a microwave absorbing material, namely Bi0.3La0.7FeO3。
XRD detection is carried out on the microwave absorbing materials prepared in examples 1-4, the detection result is shown in figure 1, and figure 1 is an XRD spectrum of the microwave absorbing materials prepared in examples 1-4. As can be seen from FIG. 1, Bi is present at a calcination temperature of 700 ℃ in the case of(0～0.3)La(0.7～1)FeO3Pure LaFeO can be obtained from the microwave absorbing material3And (4) phase(s).
The microwave absorbing materials prepared in examples 1 to 4 were tested for reflectivity loss at a thickness of 2.0mm, and the results are shown in fig. 2, and fig. 2 is a graph of reflectivity loss at a thickness of 2.0mm for the microwave absorbing materials prepared in examples 1 to 4. As can be seen from FIG. 2, Bi(0～0.3)La(0.7～1)FeO3The material moves to a low-frequency region along with the increase of Bi content, the minimum reflectivity peak values are gradually increased and are all smaller than-10 dB (the absorptivity is larger than 90%), when the Bi content is 0, 0.1, 0.2 and 0.3, the minimum reflectivity peak frequencies are respectively 14GHz, 12.8GHz, 12GHz and 11.5GHz, and the minimum reflectivity peak values are correspondingly-16.32 dB, -21.45dB, -22.44dB and-27 dBThe microwave absorbing material has excellent microwave absorbing performance in a frequency range of 10-18 GHz.
The microwave absorbing material prepared in the embodiment 1-4 is mixed with paraffin to prepare the ferrite composite wave absorbing material, and the reflectivity of the material is tested.
The determination method comprises the following steps: the microwave absorbing material is prepared from the following powder (microwave absorbing material prepared in examples 1-4): mixing paraffin wax in a mass ratio of 3: 1 to prepare coaxial samples with the outer diameter and the inner diameter of 7mm and 3mm respectively and the thickness of 3-3.5 mm, respectively measuring the complex permeability and the complex dielectric constant of the samples in a 2-18 GHz frequency band by adopting an Agilent N5230C vector network analyzer, and then calculating and simulating the reflectivity R of the single-layer wave-absorbing material by adopting the following formula:
in the formula (I), the compound is shown in the specification,r、μrand d is the relative dielectric constant, the relative permeability and the thickness of the wave-absorbing material respectively, f is the frequency of the electromagnetic wave, C is the propagation speed (namely the light speed) of the electromagnetic wave in a free space, and j is an imaginary number unit.
A. For LaFeO3The reflection rates R of the simulated single-layer wave-absorbing material with the thicknesses of 2.0mm, 2.2mm, 2.4mm and 2.6mm are calculated, and the result is shown in FIG. 3, wherein FIG. 3 is LaFeO prepared in example 13Reflectance loss plot of microwave absorbing material. It can be seen from fig. 3 that, as the matching thickness increases, the reflection ratio increases first and then decreases, and when the matching thickness is 2.2mm, the optimum microwave absorption performance is obtained at 13.44GHz, the minimum reflectivity peak is about-21.32 dB (the absorption rate is about 99%), and the optimum bandwidth effect is obtained (the maximum bandwidth effect is about: (2))<-10dB (absorption rate)>90％))3.2GHz。
B. For Bi0.1La0.9FeO3The reflection rates R of the simulated single-layer wave-absorbing material with the thicknesses of 1.8mm, 2.0mm and 2.2mm are calculated, and the result is shown in figure 4, wherein figure 4 shows that the Bi prepared in the example 20.1La0.9FeO3Reflectance loss plot of microwave absorbing material. As can be seen from FIG. 4, the reflectance shows a tendency to decrease as the thickness of the match increases, andwhen the thickness is 1.8mm, the optimal microwave absorption performance is obtained at 13.20GHz, the maximum value of the reflectivity is about-24.02 dB (the absorptivity is about 99.60%), and the optimal frequency conversion effect (I) is obtained<-10dB (absorption rate)>90％))4.48GHz。
C. For Bi0.2La0.8FeO3The calculation and simulation result shows that the single-layer wave-absorbing material has reflectivities R of 1.6mm, 1.8mm and 2.0mm respectively, and the result is shown in FIG. 5, in which FIG. 5 shows Bi prepared in example 30.2La0.8FeO3Reflectance loss plot of microwave absorbing material. As can be seen from fig. 5, the reflectance shows a tendency of decreasing first and then increasing as the matching thickness increases, and the optimum microwave absorption performance is obtained at 11.84GHz at a matching thickness of 2.0mm, with a maximum value of reflectance of about-22.44 dB (absorption of about 99.43%). And obtain the optimum wide frequency effect (c:)<-10dB (absorption rate)>90％))2.24GHz。
D. For Bi0.3La0.7FeO3The calculation and simulation result shows that the single-layer wave-absorbing material has reflectivities R of 1.6mm, 1.8mm, 2.0mm and 2.2mm respectively, and the result is shown in FIG. 6, in which FIG. 6 shows Bi prepared in example 40.3La0.7FeO3Reflectance loss plot of microwave absorbing material. It can be seen from fig. 6 that the minimum reflectance peak is less than-10 dB (absorption) in all thicknesses>90%). When the matching thickness is 2.0mm, the minimum reflectivity peak value is about-26.30 dB (the absorptivity is about 99.77%) at 11.36GHz, and the optimum frequency modulation effect (the maximum frequency modulation effect) is obtained<-10dB (absorption rate)>90％))2.48GHz。
As can be seen from the above examples and comparative examples, the perovskite structure microwave absorbing material provided by the invention can absorb electromagnetic waves in a 2-18 GHz microwave band, has a wide absorption band and high absorption efficiency (more than 90%), has good stability and oxidation resistance, and can obtain excellent microwave absorption performance when the thickness of the coating is thin within 1.6-2.0 mm, which indicates that the microwave absorbing material provided by the invention has a thin coating and excellent wave absorption performance.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A microwave absorbing material with a molecular formula of Bi(0～0.3)La(0.7～1)FeO3。
2. A microwave absorbing material as claimed in claim 1, wherein the microwave absorbing material has a molecular formula of Bi(0.1～0.3)La(0.7～0.9)FeO3。
3. A microwave absorbing material as claimed in claim 2, wherein the molecular formula of the microwave absorbing material is Bi(0.2～0.3)La(0.7～0.8)FeO3。
4. A method for preparing a microwave absorbing material as claimed in any of claims 1 to 3, comprising the steps of:
(1) mixing metal nitrate with citric acid solution, and carrying out gelation reaction to obtain gel; the metal nitrate comprises three types of bismuth nitrate, lanthanum nitrate and ferric nitrate, or two types of lanthanum nitrate and ferric nitrate;
(2) and (2) drying, ashing and calcining the gel obtained in the step (1) in sequence to obtain the microwave absorbing material.
5. The production method according to claim 4, wherein the ratio of the amount of the metal ions in the metal nitrate salt to the amount of the citric acid in the citric acid solution in the step (1) is 1: (1-2).
6. The method according to claim 4 or 5, wherein the citric acid solution in the step (1) has a mass concentration of 15.8-16.1%.
7. The preparation method according to claim 4, wherein the temperature of the gelation reaction in the step (1) is 80 to 100 ℃ and the time of the gelation reaction is 3 to 4.5 hours.
8. The preparation method according to claim 4, wherein the drying temperature in the step (2) is 80-100 ℃, and the drying time is 20-36 h.
9. The preparation method according to claim 4, wherein the ashing temperature in the step (2) is 200-300 ℃ and the ashing time is 5-10 min.
10. The preparation method according to claim 4, wherein the calcining temperature in the step (2) is 600-700 ℃, and the calcining time is 5-10 h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010805822.2A CN111892093B (en) | 2020-08-12 | 2020-08-12 | Microwave absorbing material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010805822.2A CN111892093B (en) | 2020-08-12 | 2020-08-12 | Microwave absorbing material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111892093A true CN111892093A (en) | 2020-11-06 |
| CN111892093B CN111892093B (en) | 2022-10-21 |
Family
ID=73228985
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010805822.2A Active CN111892093B (en) | 2020-08-12 | 2020-08-12 | Microwave absorbing material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111892093B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113573561A (en) * | 2021-06-16 | 2021-10-29 | 南京航空航天大学 | Perovskite type electromagnetic wave absorption material and preparation method thereof |
| CN113772627A (en) * | 2021-10-11 | 2021-12-10 | 山东大学 | Method for preparing synthesis gas by microwave thermochemical methane and application |
| CN114604858A (en) * | 2022-03-30 | 2022-06-10 | 成都大学 | Three-dimensional reduced graphene oxide rGO/ScFeO3Preparation method of composite wave-absorbing material |
| CN115784317A (en) * | 2022-11-30 | 2023-03-14 | 桂林电子科技大学 | LaCaFeO wave-absorbing material and preparation method thereof |
| CN116218027A (en) * | 2023-02-08 | 2023-06-06 | 山东大学 | Aerogel wave-absorbing material, electromagnetic wave absorber, preparation method and application thereof |
| CN116534902A (en) * | 2023-03-27 | 2023-08-04 | 桂林电子科技大学 | PrCaFeO wave-absorbing material and preparation method thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101269842A (en) * | 2008-05-07 | 2008-09-24 | 中国科学院电工研究所 | Method for preparing BiFeO3 nano-particle and fine particle |
| CN102019184A (en) * | 2010-12-27 | 2011-04-20 | 内蒙古大学 | Preparation method and application of novel perovskite photocatalyst containing bismuth |
| CN102167821A (en) * | 2011-03-24 | 2011-08-31 | 南昌航空大学 | Preparation method of lanthanum-doped barium ferrite-polyaniline composite material microwave absorbent |
| CN103771847A (en) * | 2014-01-02 | 2014-05-07 | 陕西科技大学 | La0.1Bi0.9FeO3/BiY2Fe5O12 magnetoelectric composite powder and preparation method thereof |
| CN110243878A (en) * | 2019-06-27 | 2019-09-17 | 吉林大学 | One kind is with Bi1-xLaxFeO3Electric potential type acetone sensor, preparation method and applications are blended together for sensitive electrode |
| CN111196721A (en) * | 2020-01-13 | 2020-05-26 | 桂林电子科技大学 | La1-xBixFeO3Rare earth ferrite magnetic material and preparation method thereof |
| CN111205078A (en) * | 2020-01-13 | 2020-05-29 | 桂林电子科技大学 | Bi1-xNdxFeO3Preparation method of rare earth ferrite magnetic wave-absorbing material |
-
2020
- 2020-08-12 CN CN202010805822.2A patent/CN111892093B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101269842A (en) * | 2008-05-07 | 2008-09-24 | 中国科学院电工研究所 | Method for preparing BiFeO3 nano-particle and fine particle |
| CN102019184A (en) * | 2010-12-27 | 2011-04-20 | 内蒙古大学 | Preparation method and application of novel perovskite photocatalyst containing bismuth |
| CN102167821A (en) * | 2011-03-24 | 2011-08-31 | 南昌航空大学 | Preparation method of lanthanum-doped barium ferrite-polyaniline composite material microwave absorbent |
| CN103771847A (en) * | 2014-01-02 | 2014-05-07 | 陕西科技大学 | La0.1Bi0.9FeO3/BiY2Fe5O12 magnetoelectric composite powder and preparation method thereof |
| CN110243878A (en) * | 2019-06-27 | 2019-09-17 | 吉林大学 | One kind is with Bi1-xLaxFeO3Electric potential type acetone sensor, preparation method and applications are blended together for sensitive electrode |
| CN111196721A (en) * | 2020-01-13 | 2020-05-26 | 桂林电子科技大学 | La1-xBixFeO3Rare earth ferrite magnetic material and preparation method thereof |
| CN111205078A (en) * | 2020-01-13 | 2020-05-29 | 桂林电子科技大学 | Bi1-xNdxFeO3Preparation method of rare earth ferrite magnetic wave-absorbing material |
Non-Patent Citations (3)
| Title |
|---|
| M. A. AHMED等: "Structural，magnetic and electrical properties of Bi doped LaFeO3 nano-crystals", 《JOURNAL OF MATERIALS SCIENCE：MATERIALS IN ELECTRONIC》 * |
| WANJUN LI等: "Effect of Bi-doping on the electrocatalytic properties of LaFeO3 powders prepared by sol–gel method", 《JOURNAL OF MATERIALS SCIENCE》 * |
| 赵新闻等: "Bi1−xLaxFeO3多铁体系的微波吸收性能", 《中南大学学报(自然科学版)》 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113573561A (en) * | 2021-06-16 | 2021-10-29 | 南京航空航天大学 | Perovskite type electromagnetic wave absorption material and preparation method thereof |
| CN113772627A (en) * | 2021-10-11 | 2021-12-10 | 山东大学 | Method for preparing synthesis gas by microwave thermochemical methane and application |
| CN114604858A (en) * | 2022-03-30 | 2022-06-10 | 成都大学 | Three-dimensional reduced graphene oxide rGO/ScFeO3Preparation method of composite wave-absorbing material |
| CN115784317A (en) * | 2022-11-30 | 2023-03-14 | 桂林电子科技大学 | LaCaFeO wave-absorbing material and preparation method thereof |
| CN116218027A (en) * | 2023-02-08 | 2023-06-06 | 山东大学 | Aerogel wave-absorbing material, electromagnetic wave absorber, preparation method and application thereof |
| CN116534902A (en) * | 2023-03-27 | 2023-08-04 | 桂林电子科技大学 | PrCaFeO wave-absorbing material and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111892093B (en) | 2022-10-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111892093B (en) | Microwave absorbing material and preparation method thereof | |
| CN112456562B (en) | Ferrite-based composite material and preparation method and application thereof | |
| CN109275329B (en) | A kind of preparation method of nano core-shell absorbing material | |
| CN112047386A (en) | Heating modified MXene/ferroferric oxide composite wave-absorbing material and preparation method thereof | |
| CN110550944A (en) | BaLaFeO wave-absorbing material and preparation method thereof | |
| CN114634208A (en) | Oxide composite material and preparation method and application thereof | |
| CN114715947A (en) | SrNdMnO wave absorbing material and preparation method thereof | |
| CN115784317A (en) | LaCaFeO wave-absorbing material and preparation method thereof | |
| CN111484080B (en) | Neodymium-doped praseodymium manganese oxide wave-absorbing powder material and preparation method thereof | |
| CN109294518A (en) | A kind of graphene aerogel/SiO of core-shell structure2Wave-absorbing material applied to buildings and preparation method | |
| CN111171787B (en) | BiFeO 3 /RGO composite wave-absorbing material and preparation method thereof | |
| CN103011792B (en) | Method for preparing millimeter waveband electromagnetic wave absorbing agent | |
| CN110669228B (en) | CoFe/C composite material and preparation method and application thereof | |
| CN110540735B (en) | Epoxy resin-based composite wave-absorbing material and preparation method and application thereof | |
| CN111748317A (en) | Petal-shaped ferric oxide-based composite wave absorbing agent and preparation method thereof and wave absorbing material | |
| CN107835628A (en) | A kind of Fe/Y ferrites composite wave-suction material and preparation method thereof | |
| CN103242037B (en) | Hexagonal ferrite material with high magnetic loss in L wave band and preparation method thereof | |
| CN111138184A (en) | Carbon composite cerium-doped manganese-zinc ferrite wave-absorbing material and preparation method thereof | |
| CN113511687B (en) | Wave-absorbing material and preparation method thereof | |
| CN114956192A (en) | Lanthanum-cobalt co-doped barium ferrite dual-waveband wave-absorbing powder material and preparation method thereof | |
| CN110340376A (en) | A kind of flower-shaped nickel wire absorbing material and preparation method thereof | |
| CN114044540B (en) | A-site and B-site co-doped perovskite type electromagnetic wave-absorbing material and preparation method thereof | |
| CN112280533B (en) | Preparation method of ternary composite wave-absorbing material with hollow structure | |
| CN116534902A (en) | PrCaFeO wave-absorbing material and preparation method thereof | |
| CN104402417A (en) | Rare earth ReCrO3 magnetic 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 | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Application publication date: 20201106 Assignee: Guangxi yunzhishuo Energy Technology Co.,Ltd. Assignor: GUILIN University OF ELECTRONIC TECHNOLOGY Contract record no.: X2022450000477 Denomination of invention: A microwave absorbing material and its preparation method Granted publication date: 20221021 License type: Common License Record date: 20221229 |
|
| EE01 | Entry into force of recordation of patent licensing contract |