Hollow bowl-shaped SiOCN nanoceramic wave-absorbing material, preparation method and application

Abstract

The application belongs to the technical field of nanoceramics, and particularly relates to a hollow bowl-shaped SiOCN nanoceramic wave-absorbing material, a preparation method and application. The preparation method comprises the following steps: adding a dialdehyde molecule into warm water, and fully stirring to obtain a mixed solution one, wherein the concentration of the dialdehyde molecule in the mixed solution one is 1-10 mg / mL; adding an organosiloxane into the mixed solution one, and fully stirring to obtain a mixed solution two, wherein the volume ratio of the organosiloxane to the mixed solution one is 1:10-1:50; filtering the mixed solution two to obtain white particulate matter, washing the white particulate matter multiple times by using a washing solvent, and then drying to obtain a polymer precursor powder; and heat-treating the polymer precursor powder under the protection of an inert gas to obtain the hollow bowl-shaped SiOCN nanoceramic wave-absorbing material. The hollow bowl-shaped SiOCN nanoceramic prepared by the application adds a new material form to the polymer precursor converted ceramic material, and is expected to be applied to the fields of electrochemical energy storage, electromagnetic wave absorption and photoelectrocatalysis in extreme environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano-ceramic preparation, and in particular relates to a hollow bowl-shaped SiOCN nano-ceramic absorbing material, a preparation method and an application thereof. Background Art

[0002] With the rapid development of 5G communication technology, humanity has entered a new era of the Internet of Everything. While production and life are becoming increasingly convenient, electromagnetic interference and pollution are also becoming increasingly serious. Therefore, the research and development of lightweight, high-efficiency electromagnetic wave absorbing materials has become a key development direction in the civilian high-tech field and a long-standing goal in modern military science. Polymer precursor-converted ceramic materials, primarily composed of silicon and carbon, supplemented by boron, nitrogen, and oxygen, are promising lightweight, high-efficiency, and high-temperature resistant electromagnetic wave absorbing materials due to their designable precursor molecular structure, excellent molding and machinability, and excellent heat and corrosion resistance.

[0003] The design and synthesis of nanomaterial morphologies is one of the most intriguing research areas in materials science. Currently, a variety of polymer precursor-converted ceramic materials have been successfully designed and prepared, including nanospheres, nanofibers, and three-dimensional nanoporous aerogels. Among these various nanomaterials, hollow bowl-shaped nanomaterials have attracted significant interest due to their unique physicochemical properties. On the one hand, the hollow bowl-shaped nanostructure can reduce the material's density, satisfying the requirement for a "lightweight" absorber. On the other hand, the hollow bowl-shaped nanostructure can enhance the material's internal multiple reflection and scattering of electromagnetic waves, further improving the material's attenuation capability. Therefore, combining the compositional and structural advantages of polymer precursor-converted ceramic materials and hollow bowl-shaped nanostructures, respectively, holds promise for the development of lightweight, highly efficient, and high-temperature resistant electromagnetic wave absorbers. However, the efficient and controllable preparation of hollow bowl-shaped polymer precursor-converted ceramic materials remains challenging. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for preparing a hollow bowl-shaped SiOCN nano-ceramic absorbing material, the method comprising the following steps:

[0006] (1) adding dialdehyde molecules to warm water and stirring thoroughly to obtain a mixed solution 1, wherein the concentration of the dialdehyde molecules in the mixed solution 1 is 1-10 mg / mL;

[0007] (2) adding the organosiloxane dropwise to the mixed solution 1 and stirring thoroughly to obtain a mixed solution 2 containing white particles, wherein the volume ratio of the organosiloxane to the mixed solution 1 is 1:10-1:50;

[0008] (3), the mixed solution two is filtered to obtain white granular material, the white granular material is washed multiple times using a washing solvent to remove residual reactants, and then dried to obtain a polymer precursor powder;

[0009] (4), the prepared polymer precursor powder is heat treated under inert gas protection to obtain a hollow bowl-shaped SiOCN nano ceramic wave-absorbing material.

[0010] Preferably, the dialdehyde molecule is one or more of glyoxal, terephthaldehyde and glutaraldehyde.

[0011] Preferably, the organosiloxane is one or more of 3-aminopropyl triethoxysilane, 3-aminopropyl diethoxymethylsilane and phenylaminomethyl trimethoxysilane.

[0012] Preferably, the warm water in step (1) is deionized water, and the temperature of the warm water is 60-90 DEG C.

[0013] Preferably, the stirring time of steps (1) and (2) is 1-3h, and the stirring speed is 300-600rpm.

[0014] Preferably, the washing solvent in step (3) is deionized water or ethanol or a mixed solution of the two.

[0015] Preferably, the filter membrane used in step (3) has a pore size of 500nm, the washing frequency in step (3) is 3-5 times, the drying temperature in step (3) is 30-80 DEG C, and the drying time is 6-24h.

[0016] Preferably, the heat treatment temperature in step (4) is 1000-1500 DEG C, the heat treatment time is 1-3h, and the inert gas is argon or nitrogen.

[0017] Preferably, a hollow bowl-shaped SiOCN nano ceramic wave-absorbing material is prepared by the preparation method, the ceramic wave-absorbing material comprises silicon, carbon, oxygen and nitrogen, and has a hollow bowl-shaped morphology in microcosm.

[0018] Preferably, the hollow bowl-shaped SiOCN nano ceramic wave-absorbing material is used in the field of aerospace.

[0019] The beneficial effects of the present application are:

[0020] (1), the present application is based on a molecular polymerization strategy, and a hollow bowl-shaped SiOCN nano ceramic is prepared by a template-free method, the synthesis process does not involve the removal of harmful templates, the route is simple, and the conditions are mild.

[0021] (2), the hollow bowl-shaped SiOCN nanoceramics prepared by the application adds a new material form to polymer precursor converted ceramic materials, and is expected to be applied in the fields of electrochemical energy storage, electromagnetic wave absorption and photoelectrocatalysis in extreme environments.

[0022] (3), the hollow bowl-shaped SiOCN nanoceramics prepared by the application has great advantages in the wave absorption field, the bowl-shaped porous cavity can adjust the impedance characteristics between the matching composite structure and air, and the polarization of the multi-component interface can synergistically improve the multiple reflection and absorption of electromagnetic waves, and the existence of the hollow inner cavity can reduce the density. Meanwhile, combined with the high-temperature corrosion resistance of the SiOCN ceramic material, the hollow bowl-shaped SiOCN nanoceramics can be applied as a new type of light-weight, high-efficiency and high-temperature-resistant wave-absorbing material in the field of aerospace. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0024] Figure 1 X-ray photoelectron spectroscopy of the hollow bowl-shaped SiOCN nanoceramics prepared in Example 2;

[0025] Figure 2 Scanning electron microscope picture of the hollow bowl-shaped SiOCN nanoceramics prepared in Example 2;

[0026] Figure 3 Transmission electron microscope picture of the hollow bowl-shaped SiOCN nanoceramics prepared in Example 2;

[0027] Figure 4 Reflection loss curve of the hollow bowl-shaped SiOCN nanoceramics prepared in Example 1;

[0028] Figure 5 Reflection loss curve of the hollow bowl-shaped SiOCN nanoceramics prepared in Example 2;

[0029] Figure 6 Reflection loss curve of the hollow bowl-shaped SiOCN nanoceramics prepared in Example 3. DETAILED DESCRIPTION

[0030] With reference to the accompanying drawings: clearly, the described embodiments are merely a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of the present application.

[0031] Embodiment 1

[0032] Take 100 mg of glyoxal and add it into 10 ml of deionized water, heat the water bath to 60℃, and stir for 3 h to obtain solution A. Take 1 ml of 3-aminopropyl triethoxysilane and slowly drop it into solution A, with a stirring speed of 300 rpm, to produce a white product. Wash the white product with deionized water for 3 times, and dry it at 30℃ for 24 h to obtain a polymer precursor powder. Heat the polymer precursor powder obtained above to 1000℃ at a heating rate of 1℃ / min under an argon atmosphere, keep it at 1000℃ for 3 h, and then naturally cool it to obtain a hollow bowl-shaped SiOCN nanoceramic material. The material can realize effective absorption of S, C, X and Ku bands at different thicknesses Figure 4 ). When the thickness is 2.5 mm, the lowest reflection loss of the material at 9.36 GHz (X band) reaches -22.16 dB, and the absorption rate reaches 99%.

[0033] Embodiment 2

[0034] Take 100 mg of terephthaldehyde and add it into 100 ml of deionized water, heat the water bath to 80℃, and stir for 2 h to obtain solution A. Take 2 ml of 3-aminopropyl diethoxymethylsilane and slowly drop it into solution A, with a stirring speed of 500 rpm, to produce a white product. Wash the white product with deionized water for 5 times, and dry it at 80℃ for 6 h to obtain a polymer precursor powder. Heat the polymer precursor powder obtained above to 1300℃ at a heating rate of 3℃ / min under an argon atmosphere, keep it at 1300℃ for 2 h, and then naturally cool it to obtain a hollow bowl-shaped SiOCN nanoceramic material. The material is composed of Si, C, O and N elements Figure 1 ), and presents a hollow bowl-shaped morphology Figures 2-3 ). The material can realize effective absorption of S, C, X and Ku bands at different thicknesses Figure 5). When the thickness is 1.5 mm, the lowest reflection loss of the material at 16.08 GHz (Ku band) reaches -22.84 dB, and the absorption rate reaches 99%; when the thickness is 2.3 mm, the lowest reflection loss of the material at 10.44 GHz (X band) reaches -52.93 dB, and the absorption rate reaches 99.999%; when the thickness is 4.0 mm, the lowest reflection loss of the material at 5.04 GHz (C band) reaches -39.22 dB, and the absorption rate reaches 99.9%; when the thickness is 5.0 mm, the lowest reflection loss of the material at 3.92 GHz (S band) reaches -32.24 dB, and the absorption rate reaches 99.9%.

[0035] Example 3

[0036] 50 mg glutaraldehyde was weighed into 20 ml deionized water, heated to 80°C in a water bath, and stirred for 1 h to obtain solution A. 1 ml of phenylaminomethyltrimethoxysilane was slowly added dropwise into solution A, with a stirring speed of 600 rpm, to produce a white product. The white product was washed 5 times with deionized water, and dried at 90°C for 12 h to obtain a polymer precursor powder. The polymer precursor powder was heated to 1500°C at a heating rate of 5°C / min under an argon atmosphere, and held for 1 h before natural cooling, to obtain a hollow bowl-shaped SiOCN nanoceramic material. The material can achieve effective absorption of S, C, X and Ku bands at different thicknesses Figure 5 ). When the thickness is 2.5 mm, the lowest reflection loss of the material at 11.56 GHz (X band) reaches -49.33 dB, and the absorption rate reaches 99.99%; when the thickness is 3.0 mm, the lowest reflection loss of the material at 7.69 GHz (C band) reaches -44.43 dB, and the absorption rate reaches 99.99%.

[0037] In the description of the present specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0038] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only illustrative of the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. Application of a hollow bowl-shaped SiOCN nano-ceramic material in the field of microwave absorbing materials, characterized in that: The preparation of the hollow bowl-shaped SiOCN nano-ceramic material comprises the following steps: (1) adding dialdehyde molecules to warm water and stirring thoroughly to obtain a mixed solution 1, wherein the concentration of the dialdehyde molecules in the mixed solution 1 is 1-10 mg / mL; (2) adding an organosiloxane dropwise to the mixed solution 1 and stirring thoroughly to obtain a mixed solution 2 containing white particles, wherein the volume ratio of the organosiloxane to the mixed solution 1 is 1:10-1:50; the organosiloxane is one or more of 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane and anilinomethyltrimethoxysilane; (3) filtering the mixed solution 2 to obtain white particles, washing the white particles multiple times with a washing solvent to remove residual reactants on the surface, and then drying to obtain a polymer precursor powder; (4) The prepared polymer precursor powder is heat-treated under inert gas protection to obtain a hollow bowl-shaped SiOCN nano-ceramic absorbing material; the heat treatment temperature is 1000-1500°C.

2. The use according to claim 1, characterized in that The dialdehyde molecules are one or more of glyoxal, terephthalaldehyde and glutaraldehyde.

3. The use according to claim 1, characterized in that The warm water in step (1) is deionized water, and the temperature of the warm water is 60-90°C.

4. The use according to claim 1, characterized in that Step (1) and step (2) The stirring time is 1-3h, and the stirring speed is 300-600rpm.

5. The use according to claim 1, characterized in that The washing solvent in step (3) is deionized water or ethanol or a mixed solution of the two.

6. The use according to claim 1, characterized in that In step (3), a filter membrane with a pore size of 500 nm is used for filtration, the washing times in step (3) are 3-5 times, the drying temperature in step (3) is 30-80° C., and the drying time is 6-24 hours.

7. The use according to claim 1, characterized in that In step (4), the heat treatment time is 1-3 hours, and the inert gas is argon or nitrogen.

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