Graphene-ceramic material, and preparation method therefor and use thereof

Abstract

The present invention provides a graphene-ceramic material, and a preparation method therefor and the use thereof. By means of using a two-dimensional atomic interlayer channel of a graphene oxide film to adsorb a ceramic precursor salt, an atomic-level hybrid graphene oxide film is realized. Finally, a carbide grows on the graphene in situ by means of a high-temperature reaction, thereby realizing the preparation of a graphene-ceramic hybrid material. The prepared graphene-ceramic material exhibits atomic-level hybridization of graphene ceramic carbide in the internal microstructure thereof, and can achieve layer-by-layer protection against heat. The material also exhibits extremely low thermal conductivity, and a relatively high multi-layer thermal radiation shielding capability at ultra-high temperatures, ensuring the excellent thermal insulation capability thereof at ultra-high temperatures, and thus shows great application potential in extreme thermal protection fields such as in super-speed aircrafts.

Description

A ceramic material, its preparation method and application Technical Field

[0001] This invention belongs to the field of functional materials technology, specifically relating to an olefinic ceramic material, its preparation method, and its application. Background Technology

[0002] Ceramic materials, including ceramic aerogels, are widely used in many high-temperature environments due to their excellent mechanical strength, chemical stability, and high-temperature resistance, particularly in aerospace, automotive, and energy production. However, despite their numerous advantages, their application at extremely high temperatures is affected by recrystallization. Recrystallization refers to the process by which the microstructure of a material changes due to the migration of atoms or molecules at high temperatures. This change can lead to adverse effects such as decreased mechanical properties, increased porosity, and increased thermal conductivity. Although this high-temperature limit varies depending on the specific composition and microstructure of the material, generally speaking, to effectively suppress recrystallization, most existing insulating ceramic materials can only be used in environments below 1600°C. Summary of the Invention

[0003] This invention addresses the challenge of ceramic materials recrystallizing at high temperatures, leading to large crystals, increased porosity, and increased thermal conductivity, thus hindering thermal insulation at ultra-high temperatures of 1600℃. A graphene-ceramic material is proposed to address this problem. This material achieves excellent thermal insulation at ultra-high temperatures of 2000℃ by assembling a thermal insulation framework of graphene-supported carbide ceramic nanoparticles through in-situ confined growth of carbide ceramics on a two-dimensional graphene surface.

[0004] Graphene possesses extremely high thermal conductivity, meaning it can efficiently conduct heat but cannot block it. In this invention, excellent thermal insulation is achieved by inserting graphene-anchored ceramic particle layers between continuous graphene layers. The ceramic layers reduce vertical heat conduction, thus providing insulation, while graphene efficiently conducts heat laterally, distributing heat evenly. Simultaneously, the dense structure of graphene provides a two-dimensional shielding effect, reducing thermal radiation and effectively enhancing the insulation performance. Furthermore, the excellent mechanical properties of the aerogel structure endow this graphene-ceramic aerogel with outstanding mechanical compression and elastic recovery stability against thermal expansion. In particular, when the ceramic particle layer density is low and the particles are discontinuous, this graphene-ceramic material exhibits even superior thermal insulation performance.

[0005] One of the technical solutions of this invention is to provide a graphene-ceramic material, which includes ceramic nanoparticles; and the ceramic nanoparticles are confined and grown within the graphene layers; the size of the ceramic nanoparticles is between 1-50 nm. The anchoring of the ceramic nanoparticles by the graphene effectively avoids the problem of ceramic recrystallization, the formation of large crystals, and the resulting decrease in thermal insulation performance due to increased porosity, thus enabling the graphene-ceramic material of this invention to maintain thermal insulation stability under high temperature conditions.

[0006] Furthermore, the olefin-ceramic material is an olefin-ceramic aerogel, whose porous structure can generate convection and enhance the thermal insulation effect.

[0007] The second technical solution of the present invention provides a method for preparing an olefinic ceramic material, specifically including the following steps:

[0008] (1) The graphene oxide film was immersed in the precursor salt solution for 6 hours to allow the precursor salt ions to be adsorbed between the graphene oxide surface layers. By utilizing the anchoring effect of the oxygen-containing groups in the graphene oxide film on the precursor ions of the two-dimensional material, the two-dimensional confined growth of carbides was achieved in the two-dimensional atomic channels, thereby ensuring the stable dispersion of ceramic particles;

[0009] To ensure that graphene oxide retains its structure during high-temperature carbonization, rather than being completely converted into carbides, the precursor salt should be kept at a low but uniformly distributed concentration within the graphene layers. This concentration is related to factors such as the thickness and density of the graphene oxide film used, and those skilled in the art can determine this concentration range through simple experiments.

[0010] (2) A hybrid film of graphene oxide and precursor salt was obtained by drying at room temperature;

[0011] (3) Carbonize at 1500-2800℃ for 4 hours in a tube furnace under an inert atmosphere, and the precursor salt is carbonized in situ to form carbide ceramic particles on the graphene surface.

[0012] Further, the precursor salt solution in step 1 includes one or more of zirconium chloride, tantalum chloride, niobium chloride, titanium chloride, and hafnium chloride.

[0013] Furthermore, prior to the carbonization process, the hybrid membrane is subjected to a foaming treatment to obtain an olefinic ceramic material with a porous structure; the foaming treatment specifically involves:

[0014] (1) The above hybrid membrane was subjected to solution-plastic foaming in a 30wt% hydrazine hydrate solution;

[0015] (2) The surface hydrazine hydrate solution was then washed away with ethanol and dried at room temperature to obtain a hybrid aerogel of graphene oxide and metal precursor salt.

[0016] Furthermore, the solution foaming time is 30 minutes.

[0017] The third technical solution of the present invention is to provide an application of an olefinic ceramic material in super thermal insulation, which is particularly suitable for thermal insulation above 1600 degrees Celsius.

[0018] The beneficial effects of this invention are as follows:

[0019] This invention overcomes technological bias by applying graphene, which boasts excellent thermal conductivity, to the field of thermal insulation. Furthermore, by combining this with the structural design of thermal insulation ceramic nanoparticles, a super-thermal-insulating graphene-ceramic material is obtained, significantly improving the material's thermal insulation effect and high-temperature stability. The prepared tantalum carbide-ceramic material exhibits a thermal conductivity of 21.1 mW / mK at room temperature and 213.4 mW / mK at 2000℃. Attached Figure Description

[0020] Figure 1 shows the scanning electron microscope and elemental distribution of the tantalum carbide ceramic aerogel prepared in Example 1 before and after treatment at 2000℃.

[0021] Figure 2 is a large-size physical image of the tantalum carbide ceramic aerogel prepared in Example 1.

[0022] Figure 3 is a SEM image of the tantalum carbide ceramic aerogel prepared in Example 1.

[0023] Figure 4 is a SEM image of the zirconium carbide ceramic aerogel prepared in Example 3.

[0024] Figure 5 shows the thermal conductivity of the tantalite carbide ceramic aerogel prepared in Example 1. Detailed Implementation

[0025] The following examples are provided to further illustrate the present invention and are intended to explain the invention, not to limit its scope. Unless otherwise specified, all figures are expressed in parts by weight and weight percentages.

[0026] Unless otherwise specified, the raw materials used in this invention are all conventional commercially available products; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0027] In the preparation method described in this invention, the precursor salt solution should be maintained at a concentration that ensures the presence of graphene structure after aerogel carbonization and allows ceramic nanoparticles to be uniformly distributed between graphene layers. Those skilled in the art can determine the appropriate concentration by conducting simple experiments based on the thickness of the graphene film used.

[0028] The embodiments of the present invention will be further described below with reference to several examples.

[0029] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0030] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. Example 1

[0031] Graphene oxide membranes (purchased from Hangzhou Gaoxi Technology Co., Ltd.) were immersed in a 10 mg / g tantalum chloride solution for 6 hours. After drying at room temperature, a hybrid membrane of graphene oxide and tantalum chloride was obtained. This membrane was then placed in a 30% hydrazine hydrate solution for solution foaming. After foaming for 30 minutes, the membrane was removed, and residual solvent was washed off with ethanol. After drying at room temperature, a hybrid aerogel of graphene oxide and tantalum chloride was obtained. This aerogel was then treated at 1500°C for 4 hours under an inert atmosphere in a tube furnace to obtain tantalum carbide ceramic aerogel. Figure 1 shows the scanning electron microscope and elemental distribution of the tantalum carbide ceramic aerogel before and after treatment at 2000°C. It can be seen that tantalum elements remain uniformly distributed in the porous structure of the graphene sheets after treatment at 2000°C. The ceramic particles located between the graphene layers did not aggregate, indicating that under high-temperature conditions, the ceramic particles did not agglomerate during recrystallization and maintained their original structure. The SEM image and elemental distribution are shown in Figure 3. It can be seen that the aerogel has a dense network structure, and carbon and metal elements are uniformly distributed within the aerogel. The density of the aerogel is 8.86 mg / cm³. 3 After 10,000 cycles at 99% compressive strain, the plastic deformation was only 4.5%. Figure 5 shows the thermal conductivity of the tantalite carbide ceramic aerogel prepared in this embodiment. The thermal conductivity at room temperature is 21.1 mW / mK, and the thermal conductivity at 2000℃ is 213.4 mW / mK, exhibiting excellent thermal insulation performance. Example 2

[0032] Graphene oxide film (purchased from Hangzhou Gaoxi Technology Co., Ltd.) was immersed in a 10 mg / g tantalum chloride solution for 6 hours. After drying at room temperature, a hybrid film of graphene oxide and tantalum chloride was obtained. The film was then treated at 1600 degrees Celsius for 4 hours under an inert atmosphere in a tube furnace to obtain tantalum carbide ceramic material.

[0033] Under high-temperature conditions, the ceramic particles do not agglomerate during recrystallization and maintain their original structure. The thermal conductivity at room temperature is 23.5 mW / mK, and at 2000℃ it is 243.6 mW / mK, demonstrating excellent thermal insulation properties. Example 3

[0034] Graphene oxide membrane (purchased from Hangzhou Gaoxi Technology Co., Ltd.) was immersed in a 10 mg / g zirconium chloride solution for 6 hours. After drying at room temperature, a hybrid membrane of graphene oxide and zirconium chloride was obtained. This membrane was then placed in a 30% hydrazine hydrate solution for solution foaming. After foaming for 30 minutes, it was removed, and residual solvent on the surface was washed off with ethanol. After drying at room temperature, a hybrid aerogel of graphene oxide and zirconium chloride hydrate was obtained. This aerogel was then treated at 2800°C for 4 hours under an inert atmosphere in a tube furnace to prepare zirconium carbide ceramic aerogel. Its SEM image and elemental distribution are shown in Figure 4. The aerogel exhibits a dense network structure, with carbon and metal elements uniformly distributed throughout. The aerogel density is 9.6 mg / cm³. 3 After 10,000 cycles at 99% compressive strain, the plastic deformation is only 6.5%. The thermal conductivity at room temperature is 25.1 mW / mK, and the thermal conductivity at 2000℃ is 343.8 mW / mK. Example 4

[0035] Same as Example 2, except that tantalum chloride was replaced with a mixed solution of zirconium chloride (5 mg / g) and tantalum chloride (5 mg / g) to prepare zirconium carbide tantalumene ceramic aerogel. The aerogel density was 7.6 mg / cm³. 3 After 10,000 cycles at 99% compressive strain, the plastic deformation is only 1.2%. The thermal conductivity at room temperature is 17.4 mW / mK, and the thermal conductivity at 2000℃ is 171.0 mW / mK. Example 5

[0036] Same as Example 2, except that tantalum chloride was replaced with a mixed solution of zirconium chloride (2 mg / g), tantalum chloride (3 mg / g), niobium chloride (3 mg / g), titanium chloride (1 mg / g), and hafnium chloride (1 mg / g) to prepare a high-entropy carbide olefin ceramic aerogel. The aerogel density was 9.2 mg / cm³. 3 After 10,000 cycles at 99% compressive strain, the plastic deformation was only 0.98%. The thermal conductivity at room temperature was 15.2 mW / mK, and the thermal conductivity at 2000℃ was 132.5 mW / mK. Comparative Example 1

[0037] Graphene oxide film (purchased from Hangzhou Gaoxi Technology Co., Ltd.) was immersed in a 50 mg / g zirconium chloride solution for 6 hours. After drying at room temperature, a hybrid film of graphene oxide and zirconium chloride was obtained. This film was then subjected to solution-foaming in a 30% hydrazine hydrate solution for 30 minutes. After foaming, the film was removed, and residual solvent was washed off with ethanol. After drying at room temperature, a hybrid aerogel of graphene oxide and zirconium chloride hydrate was obtained. This aerogel was then treated at 2800°C for 4 hours under an inert atmosphere in a tube furnace to prepare zirconium carbide ceramic aerogel. The aerogel has a thermal conductivity of 56 mW / mK at room temperature. At 2000°C, the ceramic crystals recombine, significantly increasing the thermal conductivity and resulting in poor insulation performance.

[0038] The above embodiments describe in detail the structure, features, and effects of the present invention. The above description is only a preferred embodiment of the present invention. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall still fall within the scope of protection of the present invention if they do not exceed the scope covered by the specification.

Claims

1. An olefinic material, characterized in that, It includes ceramic nanoparticles; and the ceramic nanoparticles are confined and grown between graphene layers; the size of the ceramic nanoparticles is between 1 and 50 nm.

2. The olefinic material of claim 1, wherein, The olefin-ceramic material is an olefin-ceramic aerogel.

3. A method of preparing an olefinic ceramic material as claimed in claim 1, characterized in that Specifically, the following steps are included: (1) The graphene oxide film was immersed in the precursor salt solution for 6 hours to allow the precursor salt ions to be adsorbed between the graphene oxide surface layers. (2) A hybrid film of graphene oxide and precursor salt was obtained by drying at room temperature; (3) Carbonize at 1500-2800℃ for 4 hours in a tube furnace under an inert atmosphere to obtain carbide graphene ceramic material by in-situ carbonization of precursor salt on graphene surface.

4. The production method according to claim 3, characterized by, The precursor salt solution in step 1 includes one or more of zirconium chloride, tantalum chloride, niobium chloride, titanium chloride, and hafnium chloride.

5. The method of claim 3, wherein, Prior to carbonization, the hybrid membrane is further subjected to a foaming treatment to obtain an olefin-ceramic aerogel material; the foaming treatment specifically involves: (1) The above hybrid membrane was subjected to solution-plastic foaming in a 30wt% hydrazine hydrate solution; (2) The surface hydrazine hydrate solution was then washed away with ethanol and dried at room temperature to obtain a hybrid aerogel of graphene oxide and metal precursor salt.

6. The production method according to claim 5, wherein The solution foaming time in step 1 is 30 minutes.

7. The application of the ceramic material as described in claim 1 in super thermal insulation.

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