A method for preparing a new type of dual-rare earth modified SiC electromagnetic wave absorbing material with multi-spectrum response and a product thereof
By constructing SiC/Ce5Si4 and SiC/Pr5Si4 interfaces in SiC materials and utilizing the catalytic properties of dual rare earth metals, the problem of insufficient absorption performance of SiC materials in multiple frequency bands was solved, achieving efficient electromagnetic wave absorption in low-frequency, mid-frequency and high-frequency bands.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JINGDEZHEN CERAMIC UNIV
- Filing Date
- 2026-01-08
- Publication Date
- 2026-06-05
AI Technical Summary
Existing SiC materials have insufficient electromagnetic wave absorption performance in multiple frequency bands, especially in low and high frequency bands, making it difficult to meet the requirements of modern electronic devices for strong multi-frequency absorption. Furthermore, existing rare earth modified materials are difficult to construct multiple heterogeneous interfaces within the material to stimulate strong polarization effects.
Using all-silica molecular sieve MFI as a template, through magnesothermic reduction and heat treatment processes, and taking advantage of the catalytic properties of the two rare earth metals Ce and Pr, SiC/Ce5Si4, SiC/Pr5Si4 and Ce5Si4/Pr5Si4 interfaces are formed to construct multiple heterogeneous interfaces to stimulate polarization loss and enhance the polarization capability of the material in low-frequency, mid-frequency and high-frequency bands.
Within a thickness of 1–5 mm, a minimum reflection loss of -64.5 dB was achieved in the 2–6 GHz low-frequency band, a minimum reflection loss of -64.67 dB in the 6–12 GHz mid-frequency band, and a minimum reflection loss of -51.89 dB in the 12–18 GHz high-frequency band, significantly enhancing the electromagnetic wave absorption capability across multiple frequency ranges.
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Figure CN122144737A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electromagnetic microwave absorption technology, and in particular to a method for preparing a novel multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material and the product obtained therefrom. Background Technology
[0002] With the rapid development of electronic information technology, electromagnetic wave technology is increasingly widely used in military radar detection, civilian wireless communication, and 5G mobile communication technology. Consequently, electromagnetic interference and compatibility issues are becoming increasingly serious. In the military field, radar systems typically operate in specific discrete spectrums, such as the C-band (4–8 GHz), X-band (8–12 GHz), and Ku-band (12–18 GHz), placing extremely high absorption intensity requirements on stealth equipment across multiple spectrums. In the civilian and 5G communication fields, complex spectrum allocations similarly necessitate materials with efficient multi-spectral absorption capabilities. However, most existing absorbing materials struggle to achieve efficient electromagnetic wave absorption across multiple spectrum bands while maintaining a relatively thin thickness. The balance between absorption intensity and spectrum coverage remains a significant challenge in this field.
[0003] Silicon carbide (SiC) materials exhibit significant advantages in electromagnetic wave absorption due to their unique physical and chemical properties (good high-temperature resistance and corrosion resistance, excellent mechanical strength and stability). However, the inherently high dielectric constant of intrinsic SiC materials leads to poor impedance matching with free space. Most incident electromagnetic waves are easily reflected at its surface, making it difficult to penetrate the material and dissipate effectively. Furthermore, its loss mechanism mainly relies on limited dielectric polarization, resulting in inherent bottlenecks in the absorption performance of intrinsic SiC materials, namely weak intensity and a single spectrum. This is particularly evident in the low-frequency bands (e.g., 2–6 GHz) where material thickness is extremely sensitive and the high-frequency bands (e.g., 12–18 GHz) where high-efficiency dielectric loss is required. These limitations make it difficult to meet the stringent requirements of modern electronic devices and stealth technologies for multi-spectral strong absorption materials. Although single rare-earth element doping has been shown to partially improve electromagnetic wave absorption performance, it is difficult to construct multiple heterogeneous interfaces within the material that can induce strong polarization effects, making it difficult to achieve efficient absorption in the low-frequency (2–6 GHz), mid-frequency (6–12 GHz), and high-frequency (12–18 GHz) spectral bands. Therefore, developing a novel dual-rare-earth modified SiC electromagnetic wave absorbing material that can achieve strong absorption across multiple spectrums and has a simple and controllable process is of great significance for overcoming current technological bottlenecks. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a novel method for preparing multi-spectral response dual-rare-earth-modified SiC electromagnetic wave absorbing materials. Using all-silicon molecular sieves (MFI) as templates, and through processes such as magnesiothermal reduction and heat treatment, the catalytic properties of dual rare-earth metals are utilized to form numerous heterogeneous interfaces, including SiC / Ce5Si4, SiC / Pr5Si4, and Ce5Si4 / Pr5Si4 interfaces. These abundant multi-heterogeneous interfaces serve as polarization centers, which are efficiently excited under an applied electromagnetic field, producing strong polarization relaxation in the low-frequency (2–6 GHz), mid-frequency (6–12 GHz), and high-frequency (12–18 GHz) bands. This significantly enhances the polarization loss capability of the material, providing an important technical approach and pathway for the design of multi-spectral response electromagnetic wave absorbing materials. Another objective of this invention is to provide products obtained using the aforementioned novel multi-spectral response dual-rare-earth-modified SiC electromagnetic wave absorbing material preparation method.
[0005] The objective of this invention is achieved through the following technical solution:
[0006] This invention provides a method for preparing a novel multi-spectral response dual-rare-earth modified SiC electromagnetic wave absorbing material, comprising the following steps:
[0007] (1) Preparation of all-silica molecular sieve MFI
[0008] Using TEOS as raw material, TPAOH as structure directing agent, and deionized water as solvent, the mixture was stirred and mixed according to the mass-volume ratio of TEOS raw material: structure directing agent: solvent = 5.5-8 g: 9-12 g: 13.5-16.5 mL. After hydrothermal reaction, the mixture was collected by centrifugation, washed, dried, and then heat-treated at 500-600℃ for 3-6 h to obtain all-silica molecular sieve MFI.
[0009] (2) Preparation of Si / SiO2 powder
[0010] (2-1) Using the aforementioned all-silica molecular sieve MFI as raw material and magnesium powder as reducing agent, the mixture is ground in a mass ratio of MFI raw material: reducing agent = 0.2-0.45 g: 0.2-0.45 g to obtain a mixed powder; the mixed powder is heat-treated in an argon atmosphere at a temperature of 650-850℃ for 4-7 h to obtain sintered powder;
[0011] (2-2) Using the sintered powder as raw material and hydrochloric acid with a concentration of 1 mol / L as detergent, the sintered powder raw material: detergent = 0.4~0.9 g: 15~30 mL is stirred and mixed, collected by centrifugation, washed and dried to obtain Si / SiO2 powder;
[0012] (3) Preparation of rare earth modified SiC powder
[0013] (3-1) Using the Si / SiO2 powder as the silicon source, sucrose as the carbon source, Ce(NO3)3·6H2O and Pr(NO3)3·6H2O as dopants, and deionized water as the solvent, the mixture was stirred and mixed according to the mass-volume ratio of silicon source: carbon source: dopant: solvent = 0.1~0.2 g: 0.2~0.4 g: 0.1~0.25 g: 10~20 mL, and then freeze-dried to obtain the mixed powder;
[0014] (3-2) The mixed powder is placed in a tube furnace, and argon gas is introduced at a flow rate of 200-400 mL / min. The temperature is increased to 700-850℃ at 2℃ / min for heat treatment, and the holding time is 1-3 h. Then, the temperature is increased to 1300-1500℃ at 5℃ / min for heat treatment, and the holding time is 1-3 h. This yields SiC / Ce5Si4 / Pr5Si4 electromagnetic wave absorbing material with multi-spectral response characteristics.
[0015] Further, in step (1) of the present invention, the stirring and mixing time is 7-10 h; the hydrothermal reaction temperature is 170-190℃, and the reaction time is 36-96 h; the centrifugation speed is 6000-10000 r / min, and the centrifugation time is 5-10 min; the washing solution is deionized water, and the washing is carried out until the pH value is neutral; the drying temperature is 70-100℃, and the drying time is 10-24 h.
[0016] Further, in step (2-1) of the present invention, the mixing and grinding time is 40-60 min; argon gas is introduced at a flow rate of 200-400 mL / min during heat treatment. In step (2-2), the stirring and mixing time is 12-28 h; the centrifugation speed is 6000-10000 r / min, and the centrifugation time is 5-10 min; the washing solution is deionized water, and washing is performed until the pH value is neutral; the drying temperature is 70-100℃, and the drying time is 10-24 h.
[0017] Furthermore, in step (3-1) of the present invention, the stirring and mixing time is 2 to 5 hours; the freeze-drying temperature is -70 to -90°C; and the freeze-drying time is 36 to 72 hours.
[0018] The product obtained by the present invention using the above-mentioned preparation method of novel multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material has the following characteristics: the minimum reflection loss of the dual rare earth modified SiC electromagnetic wave absorbing material is -64.5 dB in the low frequency band of 2-6 GHz within a thickness of 1-5 mm, -64.67 dB in the mid frequency band of 6-12 GHz, and -51.89 dB in the high frequency band of 12-18 GHz.
[0019] The present invention has the following beneficial effects:
[0020] (1) This invention uses all-silicon molecular sieve MFI as raw material and successfully constructs a composite material rich in SiC nanowires, SiC, Ce5Si4, and Pr5Si4 nanoparticles through a magnesothermic reduction method combined with a dual rare earth modification process. The material forms a large number of heterogeneous interfaces, which can be efficiently excited under the action of an external electromagnetic field, thereby significantly enhancing the polarization loss capability of the material and improving the material's efficient electromagnetic wave absorption capability in a multi-spectral range.
[0021] (2) The present invention uses all-silicon molecular sieve MFI as silicon precursor, which has a regular microporous crystal structure and extremely high specific surface area and nanoscale primary structural units. It exhibits high reactivity in subsequent carbonization reaction, which helps to reduce the SiC synthesis temperature and promote the uniform mixing of reactants at the molecular scale, thereby facilitating the generation of SiC products with uniform composition, small grain size and uniform distribution.
[0022] (3) In this invention, magnesium powder is used as a reducing agent to reduce the all-silicon molecular sieve MFI to highly active Si / SiO2 powder by magnesium thermal reduction method, and dilute hydrochloric acid solution is used to wash away the by-products (such as MgO, Mg2Si) or other impurities formed after magnesium thermal reduction, providing the prerequisite for the preparation of dual rare earth modified SiC.
[0023] (4) This invention uses rare earth metals Ce and Pr as modifying materials. By utilizing their unique 4f electronic structure and catalytic properties, the microstructure is regulated by rare earth elements to promote the in-situ generation of SiC nanowires. At the same time, rare earth silicide nanoparticles are induced to form, thereby forming a large number of heterogeneous interfaces and effectively enhancing interface polarization. This effectively optimizes polarization loss and impedance matching characteristics, overcomes the problems of single absorption spectrum and low absorption efficiency of existing microwave absorbing materials, and finally achieves compatibility between multi-spectrum and strong absorption.
[0024] (5) The SiC / Ce5Si4 / Pr5Si4 electromagnetic wave absorbing material prepared by the present invention has a minimum reflection loss of -64.5 dB in the low frequency band of 2-6 GHz, a minimum reflection loss of -64.67 dB in the mid frequency band of 6-12 GHz, and a minimum reflection loss of -51.89 dB in the high frequency band of 12-18 GHz within a thickness of 1-5 mm. It exhibits excellent multi-spectral absorption performance and overcomes the problems of single spectrum and poor absorption intensity of traditional absorbing materials.
[0025] (6) The process of the present invention has high repeatability, is easy to control, has low cost, and is easy to promote and use. Attached Figure Description
[0026] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings:
[0027] Figure 1 This is a scanning electron microscope image of the multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material prepared according to an embodiment of the present invention;
[0028] Figure 2 This is a graph showing the relationship between the imaginary part of the dielectric constant, polarization loss, and frequency of the multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material prepared in the embodiments of the present invention.
[0029] Figure 3 This is a graph showing the relationship between reflection loss and frequency of the multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material prepared in the embodiments of the present invention at different thicknesses.
[0030] Figure 4 This is a graph showing the relationship between reflection loss and frequency for the electromagnetic wave absorbing material prepared in Comparative Example 1 at different thicknesses.
[0031] Figure 5 This is a graph showing the relationship between reflection loss and frequency for the electromagnetic wave absorbing material prepared in Comparative Example 2 at different thicknesses. Detailed Implementation
[0032] Example:
[0033] This invention discloses a method for preparing a novel multi-spectral response dual-rare-earth modified SiC electromagnetic wave absorbing material, the steps of which are as follows:
[0034] (1) Preparation of all-silica molecular sieve MFI
[0035] Using TEOS as raw material, TPAOH as structure directing agent, and deionized water as solvent, 10.56 g of TPAOH was added to 15.84 mL of deionized water and stirred for 10 min, followed by the addition of 6.93 g of TEOS and stirring for 8 h. The mixture was then transferred to a 100 mL reactor and hydrothermally reacted at 180 °C for 48 h. The resulting solution and precipitate were collected by centrifugation at 8000 r / min for 5 min, washed with deionized water until the pH was neutral, dried at 100 °C for 24 h, and then heat-treated in a muffle furnace at 550 °C with a heating rate of 2 °C / min for 4 h to obtain the all-silica molecular sieve MFI.
[0036] (2) Preparation of Si / SiO2 powder
[0037] (2-1) Using the above-mentioned all-silica molecular sieve MFI as raw material and magnesium powder as reducing agent, 0.25 g of magnesium powder and 0.25 g of all-silica molecular sieve MFI were mixed and ground in an agate mortar for 45 min to obtain a mixture powder. The mixture powder was placed in a porcelain boat and placed in the middle of a quartz tube furnace. It was heat-treated in an argon atmosphere (argon gas was introduced at a flow rate of 200 mL / min) and the temperature was increased to 700℃ at 5℃ / min. The holding time was 5 h to obtain sintered powder.
[0038] (2-2) Using sintered powder as raw material and hydrochloric acid with a concentration of 1 mol / L as washing agent, the above sintered powder was slowly added to 20 mL of dilute hydrochloric acid solution with a concentration of 1 mol / L and stirred for 24 h. The resulting solution was centrifuged at 8000 r / min for 5 min and washed with deionized water until the pH was neutral. After drying at 80℃ for 12 h, Si / SiO2 powder was obtained.
[0039] (3) Preparation of rare earth modified SiC powder
[0040] (3-1) Using the above-mentioned Si / SiO2 powder as the silicon source, sucrose as the carbon source, Ce(NO3)3·6H2O and Pr(NO3)3·6H2O as dopants, and deionized water as the solvent, 0.237 g of sucrose, 0.15 g of Ce(NO3)3·6H2O, 0.151 g of Pr(NO3)3·6H2O and 0.10 g of Si / SiO2 powder were added sequentially to 10 mL of deionized water. After stirring and mixing for 3 h, the mixture was transferred to a freeze dryer and freeze-dried at -90℃ for 48 h to obtain the mixed powder.
[0041] (3-2) The above mixed powder is placed in a ceramic boat and placed in the middle of an alumina tube furnace. In an argon atmosphere (argon gas is introduced at a flow rate of 200 mL / min), the temperature is increased to 800℃ at 2℃ / min for 2 h, and then the temperature is increased to 1400℃ at 5℃ / min for 2 h. The SiC / Ce5Si4 / Pr5Si4 electromagnetic wave absorbing material with multi-spectral response characteristics is obtained.
[0042] Comparative Example 1:
[0043] Comparative Example 1 uses the preparation method of the present invention, but differs from the example in that: in step (3-1), only sucrose and Si / SiO2 powder are added to deionized water, and the pure SiC obtained by step (3-2) is used as an electromagnetic wave absorbing material.
[0044] Comparative Example 2:
[0045] Comparative Example 2 uses the preparation method of the present invention, but differs from the example in that: in step (3-1), only sucrose, Ce(NO3)3·6H2O and Si / SiO2 powder are added to deionized water, and the SiC / Ce5Si4 obtained by step (3-2) is used as an electromagnetic wave absorbing material.
[0046] The SiC / Ce5Si4 / Pr5Si4 multi-spectral electromagnetic wave absorbing material prepared in the embodiments of the present invention, such as... Figure 1 As shown, a large number of SiC nanowires, SiC, Ce5Si4, and Pr5Si4 nanoparticles were generated, forming abundant heterostructures; as Figure 2 As shown, these abundant multi-layered heterogeneous interfaces can be efficiently excited under an applied electromagnetic field, generating strong polarization relaxation (polarization peaks) in the low-frequency (2–6 GHz), mid-frequency (6–12 GHz), and high-frequency (12–18 GHz) bands, thereby significantly enhancing the material's polarization loss capability and achieving highly efficient multi-spectral electromagnetic wave absorption performance; for example... Figure 3 As shown, within a thickness of 1–5 mm, the minimum reflection loss is -64.5 dB in the low-frequency band of 2–6 GHz, -64.67 dB in the mid-frequency band of 6–12 GHz, and -51.89 dB in the high-frequency band of 12–18 GHz.
[0047] The electromagnetic wave absorbing material prepared in Comparative Example 1 is pure SiC, such as... Figure 4 As shown, within a thickness of 1–5 mm, the minimum reflection loss is -20.74 dB in the mid-frequency band of 6–12 GHz, while it does not reach -20 dB in the low-frequency band of 2–6 GHz and the high-frequency band of 12–18 GHz.
[0048] The electromagnetic wave absorbing material prepared in Comparative Example 2 is SiC / Ce5Si4, such as... Figure 5 As shown, within a thickness of 1–5 mm, the frequency did not reach -20 dB in the low-frequency band of 2–6 GHz, the mid-frequency band of 6–12 GHz, and the high-frequency band of 12–18 GHz.
[0049] The above demonstrates that, compared with the electromagnetic wave absorbing materials of Comparative Example 1 and Comparative Example 2, the embodiments of the present invention have highly efficient multi-spectral electromagnetic wave absorption capabilities.
Claims
1. A method for preparing a novel multi-spectral response dual-rare-earth modified SiC electromagnetic wave absorbing material, characterized in that... Includes the following steps: (1) Preparation of all-silica molecular sieve MFI Using TEOS as raw material, TPAOH as structure directing agent, and deionized water as solvent, the mixture was stirred and mixed according to the mass-volume ratio of TEOS raw material: structure directing agent: solvent = 5.5-8 g: 9-12 g: 13.5-16.5 mL. After hydrothermal reaction, the mixture was collected by centrifugation, washed, dried, and then heat-treated at 500-600℃ for 3-6 h to obtain all-silica molecular sieve MFI. (2) Preparation of Si / SiO2 powder (2-1) Using the aforementioned all-silica molecular sieve MFI as raw material and magnesium powder as reducing agent, the mixture is ground in a mass ratio of MFI raw material: reducing agent = 0.2-0.45 g: 0.2-0.45 g to obtain a mixed powder; the mixed powder is heat-treated in an argon atmosphere at a temperature of 650-850℃ for 4-7 h to obtain sintered powder; (2-2) Using the sintered powder as raw material and hydrochloric acid with a concentration of 1 mol / L as detergent, the sintered powder raw material: detergent = 0.4~0.9 g: 15~30 mL is stirred and mixed, collected by centrifugation, washed and dried to obtain Si / SiO2 powder; (3) Preparation of rare earth modified SiC powder (3-1) Using the Si / SiO2 powder as the silicon source, sucrose as the carbon source, Ce(NO3)3·6H2O and Pr(NO3)3·6H2O as dopants, and deionized water as the solvent, the mixture was stirred and mixed according to the mass-volume ratio of silicon source: carbon source: dopant: solvent = 0.1~0.2 g: 0.2~0.4 g: 0.1~0.25 g: 10~20 mL, and then freeze-dried to obtain the mixed powder. (3-2) The mixed powder is placed in a tube furnace, and argon gas is introduced at a flow rate of 200-400 mL / min. The temperature is increased to 700-850℃ at 2℃ / min for heat treatment, and the holding time is 1-3 h. Then, the temperature is increased to 1300-1500℃ at 5℃ / min for heat treatment, and the holding time is 1-3 h. This yields SiC / Ce5Si4 / Pr5Si4 electromagnetic wave absorbing material with multi-spectral response characteristics.
2. The preparation method of the novel multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material according to claim 1, characterized in that: In step (1), the stirring and mixing time is 7–10 h; the hydrothermal reaction temperature is 170–190℃, and the reaction time is 36–96 h; the centrifugation speed is 6000–10000 r / min, and the centrifugation time is 5–10 min; the washing solution is deionized water, and the washing is carried out until the pH value is neutral; the drying temperature is 70–100℃, and the drying time is 10–24 h.
3. The preparation method of the novel multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material according to claim 1, characterized in that: The mixing and grinding time in step (2-1) is 40 to 60 minutes; argon gas is introduced at a flow rate of 200 to 400 mL / min during heat treatment.
4. The preparation method of the novel multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material according to claim 1, characterized in that... In step (2-2), the stirring time is 12-28 h; the centrifugation speed is 6000-10000 r / min, and the centrifugation time is 5-10 min; the washing solution is deionized water, and the washing is carried out until the pH value is neutral; the drying temperature is 70-100℃, and the drying time is 10-24 h.
5. The preparation method of the novel multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material according to claim 1, characterized in that: The mixing time in step (3-1) is 2 to 5 hours; the freeze-drying temperature is -70 to -90°C, and the freeze-drying time is 36 to 72 hours.
6. The product prepared by the method of preparing the novel multi-spectral response dual rare earth modified SiC electromagnetic wave absorbing material according to any one of claims 1-5.
7. The product according to claim 6, characterized in that: The dual rare earth modified SiC electromagnetic wave absorbing material has a minimum reflection loss of -64.5 dB in the low-frequency band of 2–6 GHz, a minimum reflection loss of -64.67 dB in the mid-frequency band of 6–12 GHz, and a minimum reflection loss of -51.89 dB in the high-frequency band of 12–18 GHz within a thickness of 1–5 mm.