An enstatite material, its preparation method and use

Abstract

This invention proposes an olefin ceramic material, its preparation method, and its application. By utilizing the two-dimensional atomic interlayer channels of a graphene oxide film to adsorb ceramic precursor salts, this creates an atomic-level hybrid graphene oxide film. Finally, through a high-temperature reaction, carbides are grown in situ on the graphene, resulting in the preparation of a graphene-ceramic hybrid material. The prepared olefin ceramic material exhibits an atomic-level hybridization of graphene, ceramic, and carbide within its internal microstructure, providing layered thermal protection, exhibiting extremely low thermal conductivity, and possessing high multi-layered thermal radiation shielding capabilities at ultra-high temperatures. This ensures excellent thermal insulation at ultra-high temperatures, demonstrating significant potential for applications in extreme thermal protection applications such as those for ultra-high-speed aircraft.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and in particular relates to an olefin ceramic material and a preparation method and application thereof. Background Art

[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, especially in aerospace, automotive industry and energy production. However, despite the many advantages of ceramic materials, their application at extremely high temperatures is affected by the phenomenon of recrystallization. Recrystallization refers to the process in which the microstructure of a material changes due to the migration of atoms or molecules at high temperatures. This change may 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, in general, in order to effectively inhibit the occurrence of recrystallization, most existing thermal insulation ceramic materials can only be used in environments below 1600°C. Summary of the Invention

[0003] This paper addresses the problem of ceramic materials recrystallizing at high temperatures, forming large crystals. This leads to larger pores, increased thermal conductivity, and a failure to insulate at ultra-high temperatures of 1600°C. This material, developed by in-situ confined growth of carbide ceramics on a two-dimensional graphene surface, assembles a thermal insulation framework of graphene-loaded carbide ceramic nanoparticles, achieving excellent thermal insulation at ultra-high temperatures of 2000°C.

[0004] Graphene has extremely high thermal conductivity, which means that it can conduct heat efficiently but cannot block heat transfer. In the present invention, an excellent thermal insulation effect is achieved by inserting a ceramic particle layer anchored by graphene between continuous graphene layers. The ceramic layer can reduce heat conduction in the vertical direction and thus insulate, while graphene can efficiently conduct heat in the lateral direction and evenly distribute heat. At the same time, the dense structure of graphene has a two-dimensional shielding effect that can reduce thermal radiation and effectively enhance the thermal insulation effect. In addition, the excellent mechanical properties of the aerogel structure give the olefin ceramic aerogel excellent elastic recovery stability against mechanical compression and thermal expansion. In particular, when the density of the ceramic particle layer is low and the particles are discontinuous, this olefin ceramic material exhibits even better thermal insulation properties.

[0005] One of the technical solutions of the present invention is to provide an olefin-ceramic material comprising ceramic nanoparticles confined and grown between graphene layers, with the ceramic nanoparticles ranging in size from 1 to 50 nm. The anchoring of the ceramic nanoparticles by graphene effectively prevents recrystallization of the ceramic, which results in large crystals and, consequently, increased voids and a consequent decline in thermal insulation performance. This ensures that the olefin-ceramic material maintains thermal insulation stability even under high-temperature conditions.

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

[0007] The second technical solution of the present invention is to provide a method for preparing an olefin ceramic material, which specifically comprises the following steps:

[0008] (1) Immerse the graphene oxide film in a precursor salt solution for 6 hours to allow the precursor salt ions to adsorb between the surface layers of the graphene oxide. Utilizing the anchoring effect of oxygen-containing groups in the graphene oxide film on the two-dimensional material precursor ions, the two-dimensional confined growth of carbides is achieved within 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 to carbide, the precursor salt should be maintained at a low concentration that is evenly distributed between the graphene layers. This concentration depends on factors such as the thickness and density of the graphene oxide film being used, and those skilled in the art can determine this concentration range through simple experiments.

[0010] (2) Drying at room temperature to obtain a hybrid film of graphene oxide and precursor salt;

[0011] (3) Carbonization at 1500-2800 °C for 4 hours in a tube furnace under inert atmosphere. The precursor salt is carbonized in situ to form carbide ceramic particles on the surface of graphene.

[0012] Furthermore, 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, before the carbonization treatment, the hybrid membrane is subjected to a foaming treatment to obtain an olefin-ceramic material having a porous structure; the foaming treatment is specifically as follows:

[0014] (1) subjecting the hybrid membrane to dissolution-plastic foaming in a 30 wt% 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 time for the dissolution-plastic foaming is 30 minutes.

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

[0018] The beneficial effects of the present invention are:

[0019] This invention overcomes technical prejudices by applying graphene, a material with excellent thermal conductivity, to thermal insulation. Combined with the structural design of insulating ceramic nanoparticles, this method creates a super-insulating tantalum carbide tantalum ceramic material, significantly improving its thermal insulation and high-temperature stability. The resulting tantalum carbide tantalum ceramic material exhibits a thermal conductivity of 21.1 mW / mK at room temperature and 213.4 mW / mK at 2000°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The scanning electron microscope and element distribution diagram of the tantalum carbide ceramic aerogel prepared in Example 1 before and after treatment at 2000°C.

[0021] Figure 2 This is a large-scale, physical picture of the tantalum carbide ceramic aerogel prepared in Example 1.

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

[0023] Figure 4 This is the SEM image of the carbonized zirconium ene ceramic aerogel prepared in Example 3.

[0024] Figure 5 The thermal conductivity of the tantalum carbide ceramic aerogel prepared in Example 1. DETAILED DESCRIPTION

[0025] The following examples are used to further illustrate the present invention. Their purpose is to illustrate the present invention and should not be construed as limiting the scope of the present invention. Unless otherwise specified, all references are by weight and weight percentage.

[0026] Unless otherwise specified, the raw materials used in the present invention are conventional commercial products; the methods used in the present invention are conventional methods in the art unless otherwise specified.

[0027] In the preparation method described in the present invention, the precursor salt solution should be maintained at a concentration that allows graphene structures to remain after the aerogel is carbonized and enables ceramic nanoparticles to be evenly 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 are further described below with reference to a number of embodiments.

[0029] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0030] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0031] Example 1

[0032] The graphene oxide film (purchased from Hangzhou Gaoxin Technology Co., Ltd.) was immersed in a 10 mg / g tantalum chloride salt solution for 6 hours, and after drying at room temperature, a hybrid film of graphene oxide and tantalum chloride was obtained. It was then placed in a 30% hydrazine hydrate solution for dissolution and plastic foaming. After foaming for 30 minutes, it was taken out and the residual solvent on its surface was washed away with ethanol. After drying at room temperature, a hybrid aerogel of graphene oxide and tantalum chloride hydrate was obtained. It was placed in a tubular furnace under inert atmosphere protection at 1500 degrees Celsius for 4 hours to obtain tantalum carbide ceramic aerogel. Figure 1 The scanning electron microscope and element distribution diagram of the tantalum carbide ceramic aerogel before and after treatment at 2000℃ show that the tantalum element is still evenly distributed in the porous structure composed of graphene sheets after treatment at 2000℃, and the ceramic particles between the graphene layers do not aggregate, indicating that under high temperature conditions, the ceramic particles do not agglomerate during the recrystallization process and can maintain their original structure. Figure 3 As shown, the aerogel has a dense network structure, and the carbon and metal elements are evenly distributed in the aerogel. The density of the aerogel is 8.86 mg / cm 3 , after 10,000 cycles at 99% compressive strain, the plastic deformation is only 4.5%. Figure 5 The thermal conductivity of the tantalum carbide ceramic aerogel prepared in this example is 21.1 mW / mK at room temperature and 213.4 mW / mK at 2000°C, which shows excellent thermal insulation effect.

[0033] Example 2

[0034] The graphene oxide film (purchased from Hangzhou Gaoxin Technology Co., Ltd.) was immersed in a 10 mg / g tantalum chloride salt solution for 6 hours. After drying at room temperature, a hybrid film of graphene oxide and tantalum chloride was obtained. The hybrid film was placed in a tubular furnace under inert atmosphere protection at 1600 degrees Celsius for 4 hours to obtain tantalum carbide ceramic material.

[0035] Under high temperature conditions, the ceramic particles do not agglomerate during the recrystallization process and can maintain their original structure. The thermal conductivity at room temperature is 23.5mW / mK, and the thermal conductivity at 2000℃ is 243.6mW / mK, which has excellent thermal insulation effect.

[0036] Example 3

[0037] The graphene oxide film (purchased from Hangzhou Gaoxin Technology Co., Ltd.) was immersed in a 10 mg / g zirconium chloride salt solution for 6 hours, and after drying at room temperature, a hybrid film of graphene oxide and zirconium chloride was obtained. It was then placed in a 30% hydrazine hydrate solution for dissolution and plastic foaming. After foaming for 30 minutes, it was taken out and the residual solvent on its surface was washed away with ethanol. After drying at room temperature, a hybrid aerogel of graphene oxide and zirconium chloride hydrate was obtained. It was placed in a tubular furnace under inert atmosphere protection at 2800 degrees Celsius for 4 hours to prepare carbonized zirconium ene ceramic aerogel. Its SEM image and element distribution are shown in Figure 2. Figure 4 As shown, the aerogel has a dense network structure, and the carbon and metal elements are evenly distributed in the aerogel. The density of the aerogel is 9.6 mg / cm 3 After 10,000 cycles of compression strain at 99%, the plastic deformation is only 6.5%. The thermal conductivity is 25.1 mW / mK at room temperature and 343.8 mW / mK at 2000°C.

[0038] Example 4

[0039] The same as Example 2, except that tantalum chloride was replaced by a mixed solution of zirconium chloride and tantalum chloride, to prepare zirconium carbide tantalum olefin ceramic aerogel. The aerogel density was 7.6 mg / cm 3 After 10,000 cycles of compression at 99%, the plastic deformation is only 1.2%. The thermal conductivity is 17.4 mW / mK at room temperature and 171.0 mW / mK at 2000°C.

[0040] Comparative Example 1

[0041] A graphene oxide film (purchased from Hangzhou Gaoxi Technology Co., Ltd.) was immersed in a 50 mg / g zirconium chloride salt solution for 6 hours. After drying at room temperature, a graphene oxide / zirconium chloride hybrid film was obtained. The film was then placed in a 30% hydrazine hydrate solution for solution-plastic foaming. After foaming for 30 minutes, the film was removed and the residual solvent on the surface was washed with ethanol. After drying at room temperature, a graphene oxide / zirconium chloride hydrate hybrid aerogel was obtained. This aerogel was then treated in a tubular furnace under an inert atmosphere at 2800°C for 4 hours to prepare carbonized zirconium ene ceramic aerogel. The thermal conductivity of the aerogel was 56 mW / mK at room temperature. At 2000°C, the ceramic crystals reassembled, significantly increasing the thermal conductivity and resulting in poor insulation.

[0042] The above embodiments describe in detail the structure, features and effects of the present invention. The above are only preferred embodiments of the present invention. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the scope covered by the specification, should be within the scope of protection of the present invention.

Claims

1. An olefin ceramic material, characterized in that: The ceramic nanoparticles are confined and grown between graphene layers; and the size of the ceramic nanoparticles is between 1 and 50 nm. The olefin ceramic material is prepared by the following steps: (1) Immersing the graphene oxide film in a precursor salt solution for 6 hours to allow the precursor salt ions to be adsorbed between the surface layers of the graphene oxide; the precursor salt solution includes one or more of zirconium chloride, tantalum chloride, niobium chloride, titanium chloride, and hafnium chloride; (2) Drying at room temperature to obtain a hybrid film of graphene oxide and precursor salt; (3) Carbonization was performed at 1500-2800°C for 4 hours in a tubular furnace under inert atmosphere. The precursor salt was in situ carbonized on the graphene surface to obtain a carbide-ceramic material.

2. The olefin ceramic material according to claim 1, characterized in that: The olefin ceramic material is olefin ceramic aerogel.

3. The material according to claim 1, characterized in that Before the carbonization treatment, the hybrid membrane is further subjected to a foaming treatment to obtain an olefin-ceramic aerogel material; the foaming treatment is specifically as follows: (1) subjecting the hybrid membrane to dissolution-plastic foaming in a 30 wt% 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.

4. The material according to claim 3, characterized in that The time for the dissolving and foaming in step 1 is 30 minutes.

5. Use of the olefin ceramic material according to claim 1 in super thermal insulation.

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