Double-morphology flexible film and powder and carbon template synergistic preparation method thereof
By using a co-preparation method of thin carbon felt and precursor powder, a flexible film with dual morphology of SiC microtubes/SiC nanowires was successfully prepared, which solved the problem that the high temperature resistance of single morphology films in the prior art is below 1300 ℃, and achieved high temperature resistance of 1400 ℃ without damage and efficient preparation.
Patent Information
- Application Number
- CN202511320693.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-16
- Publication Date
- 2026-01-02
AI Technical Summary
Existing technologies can only produce nanowire films with one morphology, and their high-temperature resistance is generally below 1300 ℃, making it impossible to prepare flexible films with dual morphologies.
A flexible film with dual morphology of SiC microtubes/SiC nanowires was prepared in one step by using thin carbon felt as a carbon template and precursor powder in synergistic preparation. The thin carbon felt serves as the nucleation framework for SiC microtubes and provides a carbon source, while SiC nanowires are grown in situ.
A one-step fabrication of flexible films with dual morphologies of SiC microtubes and SiC nanowires was achieved, which can withstand high temperatures of 1400 ℃ without damage, improving the temperature resistance index by 100 ℃. Furthermore, the excessive shrinkage of the film was suppressed by the interlacing of nanowires of different sizes, thereby improving the dimensional stability and crack resistance in high-temperature environments.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of flexible high-temperature resistant materials technology, specifically relating to a dual-morphology flexible thin film and its powder and carbon template co-preparation method. Background Technology
[0002] High-temperature resistant materials, as fundamental functional materials in high-temperature industries, are widely used in metallurgy, building materials, chemical industry, and energy. While traditional high-temperature resistant materials (such as corundum bricks and magnesia-carbon bricks) possess excellent high-temperature resistance and chemical stability, they generally suffer from high brittleness, poor thermal shock resistance, and difficulty in adapting to complex, irregularly shaped workpiece structures. In recent years, flexible high-temperature resistant materials have attracted attention due to their unique bendability and resistance to mechanical vibration. These materials are typically made of ceramic fibers or ceramic nanowires, offering advantages in both lightweight and convenience. However, existing flexible high-temperature resistant materials still have significant drawbacks: First, ceramic fibers, which exhibit good flexibility at medium and low temperatures, often become brittle and lose their deformability at high temperatures (>1000 ℃) due to component decomposition or fiber crystallization. Second, ceramic nanofiber films, especially SiC nanowire films with excellent high-temperature resistance, suffer from complex preparation processes and cannot be generated in a single step to form a dual-morphology flexible film. Therefore, developing a nanowire film with a simple process that combines high flexibility retention and high-temperature resistance is of paramount importance.
[0003] Reference 1, “Y. Liu, L. Zhang, R. Zhang, S. Shao, L. Sun, X. Wan, T. Wang, Thermal insulating and fire-retardant Si3N4 nanowire membranes resistant to high temperatures up to 1300 ℃, Journal of Materials Science & Technology, 155(2023) 82-88,” reports a single Si3N4 nanowire thin film that can withstand high temperatures up to 1300 ℃ in air.
[0004] Reference 2, “S. He, K. Li, Q. Liu, S. Gu, Q. Song, Flexible SiC-nanowiremembrane reinforced pyrocarbon profiled joints with significantly improved thermal shock resistance, Ceramics International, 45 (2019) 2241-2249,” reports a single SiC nanowire thin film.
[0005] Reference 3, “Su L, Wang H, Niu M, et al. Ultralight, recoverable, and high-temperature-resistant SiC nanowire aerogel. ACS Nano, 2018, 12(4): 3103-3111,” reports a single SiC nanowire thin film that can withstand a high temperature of 900 °C in air.
[0006] Reference 4, “F. Chen, Y. Zhu, Large-Scale Automated Production of HighlyOrdered Ultralong Hydroxyapatite Nanowires and Construction of Various Fire-Resistant Flexible Ordered Architectures. ACS Nano 2016, 10 (12), 11483-11495,” reports a single hydroxyapatite nanowire thin film that can withstand a high temperature of 650 °C in air.
[0007] The aforementioned literature has prepared high-temperature resistant flexible films with single-phase nanowires, but there are two problems: First, the flexible films prepared above only produce nanowires of one morphology, and no one has achieved the one-step preparation of flexible films with two morphologies; Second, the high-temperature resistance of the flexible films reported above is generally lower than 1300 °C. Summary of the Invention
[0008] In order to overcome the shortcomings of the prior art, the present invention aims to provide a dual-morphology flexible film and a method for the synergistic preparation of its powder and carbon template, so as to solve the technical problems of the prior art which only prepares nanowires of one morphology, has not achieved one-step preparation of dual-morphology flexible films, and the high temperature resistance index of flexible films is generally lower than 1300 °C.
[0009] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a method for the synergistic preparation of a dual-morphology flexible thin film using powder and a carbon template, comprising the following steps: A solution was prepared by uniformly mixing tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid, and deionized water; the solution was then allowed to stand and solidify before being ground into precursor powder. Cut carbon felt sheets were placed on precursor powder and subjected to high-temperature heat treatment, followed by low-temperature oxidation treatment to obtain a flexible SiC microtube / SiC nanowire dual-morphology film.
[0010] In one embodiment, the volume ratio of deionized water to tetraethoxysilane is 2:1-5:1; the mass ratio of tetraethoxysilane to hexadecyltrimethylammonium bromide is 365:1-375:1; and the volume ratio of deionized water to hydrochloric acid is 75:1-85:1.
[0011] In one embodiment, the concentration of the hydrochloric acid is 1 mol / L.
[0012] In one embodiment, the settling and curing time is 1-2 days.
[0013] In one embodiment, the cut carbon felt sheet has dimensions of 30-100 mm in length, 10-40 mm in width, and 3-10 mm in thickness.
[0014] In one embodiment, the thickness of the precursor powder is 0.5-2 mm.
[0015] In one embodiment, the high-temperature heat treatment process is as follows: The precursor powder is evenly spread on graphite paper, and a thin sheet of carbon felt is placed on the precursor powder. Then another layer of graphite paper is added, and the mixture is placed in a high-temperature tube heat treatment chamber and heat-treated at 1400-1600 °C for 1-3 hours in an argon atmosphere at a pressure of 0.05-0.20 MPa. The mixture is then cooled to room temperature.
[0016] In one embodiment, the low-temperature oxidation process is as follows: The product that has undergone high-temperature heat treatment is placed in a low-temperature oxidation furnace at 600-900 ℃ and oxidized in air for 1-4 hours, and then cooled to room temperature.
[0017] The present invention also provides a dual-morphology flexible film prepared by a method of co-preparation of powder and carbon template using a dual-morphology flexible film, wherein the dual-morphology flexible film is composed of SiC microtubes and SiC nanowires, and the SiC microtubes and SiC nanowires are randomly intertwined and wound together.
[0018] The aforementioned dual-morphology flexible film can withstand a temperature of 1400 ℃ for up to 15 minutes in air without damage.
[0019] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for the synergistic preparation of a dual-morphology flexible thin film using powder and a carbon template. The innovation of this method lies in the selection of a thin carbon felt sheet as the carbon template and the prepared precursor powder as the silicon source. The thin carbon felt sheet serves to provide a nucleation framework for the formation of SiC microtubes and a carbon source for the growth of SiC nanowires. The formation of SiC nanowires requires in-situ growth of the precursor powder using the carbon felt sheet as a template at high temperatures. The powder-like design effectively avoids the ceramic block phenomenon that occurs during high-temperature heat treatment in impregnation methods, enabling the acquisition of high-purity SiC nanowires. By successfully combining the thin carbon felt sheet and the precursor powder, a one-step preparation of a dual-morphology flexible thin film of SiC microtubes / SiC nanowires is achieved. This preparation method not only achieves one-step preparation of a dual-morphology flexible thin film of SiC microtubes / SiC nanowires, but the resulting SiC microtubes / SiC nanowires dual-morphology flexible thin film also withstands a high temperature of 1400 °C for up to 15 minutes in air without damage.
[0020] This invention provides a dual-morphology flexible film comprising SiC microtubes and SiC nanowires, which are randomly intertwined and wound together. The dual-morphology nanowires of different sizes have different shrinkage rates. This difference can restrain each other, suppressing excessive shrinkage of the film as a whole to a certain extent, reducing internal stress, and thus improving the dimensional stability and crack resistance of the film in high-temperature environments. Attached Figure Description
[0021] Figure 1 Images (a) to (d) are optical images of the SiC microtube / SiC nanowire dual-morphology flexible thin film prepared in Example 3; Figure 2 Images (a) to (c) are scanning electron microscope images and corresponding elemental distribution diagrams of the SiC microtube / SiC nanowire dual-morphology flexible thin film prepared in Example 3; Figure 3 Images (a) to (c) are transmission electron microscope (TEM) images of the SiC microtube / SiC nanowire dual-morphology flexible thin film prepared in Example 3. Figure 4 In the middle (a) and (b), respectively, optical images of the SiC microtube / SiC nanowire dual-morphology flexible thin film prepared in Example 3 were subjected to a high-temperature oxidation test at 1400 °C for 15 min. Figure 5 This is an optical image of a small amount of SiC nanowires that cannot form a film independently, prepared in Comparative Example 1. Figure 6 This is an optical image of the rigid and fragile material prepared in Comparative Example 2; Figure 7 These are SEM images and corresponding schematic diagrams of the SiC microtubes and SiC nanowires in the SiC microtube / SiC nanowire dual-morphology flexible thin film prepared by this invention. Detailed Implementation
[0022] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.
[0023] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.
[0024] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values (including integers and fractions) within those ranges.
[0025] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”
[0026] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.
[0027] To achieve one-step fabrication of flexible films with dual morphologies and improve their high-temperature resistance while maintaining flexibility, this invention provides a method for the synergistic preparation of flexible films with dual morphologies and their powder and carbon template. A method for synergistically preparing SiC microtube / SiC nanowire flexible films with precursor powder and carbon template is designed. This method uses a thin carbon felt sheet as the carbon template and a precursor powder (made by mixing and drying tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid, and deionized water) as the silicon source. The SiC microtube / SiC nanowire flexible films are prepared in one step using high-temperature heat treatment and low-temperature oxidation techniques.
[0028] This invention utilizes thin-film carbon felt and precursor powder as carbon templates and silicon sources, respectively, to prepare a flexible SiC microtube / SiC nanowire dual-morphology film. On one hand, it achieves one-step preparation of the SiC microtube / SiC nanowire dual-morphology flexible film, which is more efficient than the film preparation process shown in the prior art; on the other hand, it achieves high-temperature resistance of 1400 ℃ for up to 15 minutes without damage, which is 100 ℃ higher than the highest temperature resistance of the prior art.
[0029] Specifically, a method for synergistically preparing SiC microtube / SiC nanowire dual-morphology flexible thin films using powder and carbon template is provided, comprising the following steps: (1) Tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid (1 mol / L), and deionized water are mixed evenly. The volume ratio of deionized water to tetraethoxysilane is 2:1-5:1; the mass ratio of tetraethoxysilane to hexadecyltrimethylammonium bromide is 365:1-375:1; and the volume ratio of deionized water to hydrochloric acid is 75:1-85:1. After mixing evenly, solution A is obtained. (2) Let solution A stand for 1-2 days to solidify, then grind it in a mortar into precursor powder B; (3) Cut the thin carbon felt into dimensions of 30-100 mm in length, 10-40 mm in width, and 3-10 mm in thickness to obtain carbon felt C; (4) Spread the precursor powder B evenly in the graphite paper with a thickness of 0.5-2 mm. Then place the carbon felt C on the precursor powder B and cover it with another layer of graphite paper. (5) Place the sample from step (4) above in a high-temperature tubular heat treatment chamber for 1-3 hours. The temperature is set to 1400-1600 ℃ and the argon gas pressure is 0.05-0.20 MPa. After the furnace cools to room temperature, sample D is obtained. (6) Place sample D in a low-temperature oxidation furnace at 600-900 ℃ and oxidize it in air for 1-4 hours. After the low-temperature oxidation furnace cools to room temperature, take out the sample to obtain a flexible film with dual morphology of SiC microtubes / SiC nanowires.
[0030] like Figure 7 As shown, in the SiC microtube / SiC nanowire dual-morphology flexible thin film prepared by the above method, the SiC microtubes and SiC nanowires are randomly intertwined and entangled.
[0031] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.
[0032] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.
[0033] Example 1 This embodiment provides a method for synergistically preparing SiC microtube / SiC nanowire dual-morphology flexible thin films using powder and carbon template, including the following steps: (1) Tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid (1 mol / L), and deionized water are mixed evenly. The volume ratio of deionized water to tetraethoxysilane is 3:1; the mass ratio of tetraethoxysilane to hexadecyltrimethylammonium bromide is 365:1; and the volume ratio of deionized water to hydrochloric acid is 75:1. After mixing evenly, solution A is obtained. (2) Let solution A stand for 1 day to solidify, then grind it into powder B in a mortar; (3) Cut the thin carbon felt into dimensions of 30 mm in length, 10 mm in width and 3 mm in thickness to obtain carbon felt C; (4) Spread powder B evenly in graphite paper with a thickness of 0.5 mm, then place carbon felt C on the powder and cover it with another layer of graphite paper. (5) The sample from step (4) above was placed in a high-temperature tubular heat treatment chamber for 1 hour. The temperature was set to 1400 °C and the argon pressure was 0.05 MPa. After the furnace cooled to room temperature, sample D was obtained. (6) Place sample D in a low-temperature oxidation furnace at 600 °C and oxidize it in air for 4 hours. After the low-temperature oxidation furnace cools to room temperature, take out the sample to obtain a large-size single-phase SiC nanowire refractory film.
[0034] Example 1 successfully prepared a flexible SiC microtube / SiC nanowire film, which withstood a high temperature of 1400 °C for 10 min without damage.
[0035] Example 2 This embodiment provides a method for synergistically preparing SiC microtube / SiC nanowire dual-morphology flexible thin films using powder and carbon template, including the following steps: (1) Tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid (1 mol / L), and deionized water are mixed evenly. The volume ratio of deionized water to tetraethoxysilane is 4:1; the mass ratio of tetraethoxysilane to hexadecyltrimethylammonium bromide is 375:1; and the volume ratio of deionized water to hydrochloric acid is 85:1. After mixing evenly, solution A is obtained. (2) Let solution A stand for 2 days to solidify, then grind it into powder B in a mortar; (3) Cut the thin carbon felt into dimensions of 100 mm in length, 40 mm in width and 10 mm in thickness to obtain carbon felt C; (4) Spread powder B evenly in graphite paper with a thickness of 2 mm, then place carbon felt C on the powder and cover it with another layer of graphite paper. (5) The sample from step (4) above was placed in a high-temperature tubular heat treatment chamber for 3 hours. The temperature was set to 1600 °C and the argon gas pressure was 0.20 MPa. After the furnace cooled to room temperature, sample D was obtained. (6) Place sample D in a low-temperature oxidation furnace at 900 °C and oxidize it in air for 1 hour. After the low-temperature oxidation furnace cools to room temperature, take out the sample to obtain a large-size single-phase SiC nanowire refractory film.
[0036] Example 2 successfully prepared a flexible SiC microtube / SiC nanowire film, which withstood a high temperature of 1400 °C for 12 minutes without damage.
[0037] Example 3 This embodiment provides a method for synergistically preparing SiC microtube / SiC nanowire dual-morphology flexible thin films using powder and carbon template, including the following steps: (1) Tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid (1 mol / L), and deionized water are mixed evenly. The volume ratio of deionized water to tetraethoxysilane is 2:1; the mass ratio of tetraethoxysilane to hexadecyltrimethylammonium bromide is 372:1; and the volume ratio of deionized water to hydrochloric acid is 80:1. After mixing evenly, solution A is obtained. (2) Let solution A stand for 1 day to solidify, then grind it into powder B in a mortar; (3) Cut the thin carbon felt into dimensions of 90 mm in length, 30 mm in width, and 5 mm in thickness to obtain carbon felt C; (4) Spread powder B evenly in graphite paper with a thickness of 1 mm, then place carbon felt C on the powder and cover it with another layer of graphite paper. (5) The sample from step (4) above was placed in a high-temperature tubular heat treatment chamber for 2 hours. The temperature was set to 1500 °C and the argon pressure was 0.10 MPa. After the furnace cooled to room temperature, sample D was obtained. (6) Place sample D in a low-temperature oxidation furnace at 700 °C and oxidize it in air for 2 hours. After the low-temperature oxidation furnace cools to room temperature, take out the sample to obtain a large-size single-phase SiC nanowire refractory film.
[0038] Example 3 successfully prepared a flexible SiC microtube / SiC nanowire film, which withstood a high temperature of 1400 °C for 15 min without damage.
[0039] Figure 1 This demonstrates the flexible thin film with a dual morphology of SiC microtubes / SiC nanowires prepared in Example 3. Figure 1 (a) shows the overall dimensions of the film. Figure 1 (b) to (d) demonstrate the flexibility of the film, which can be bent at will and wrapped around a glass rod. After being unwound, the film can still return to its original shape, demonstrating the excellent flexibility of the film.
[0040] Figure 2 Scanning electron microscope images and corresponding elemental distribution maps of the SiC microtube / SiC nanowire dual-morphology flexible thin film prepared in Example 3 are shown. Figure 2 (a) shows two morphologies contained in the thin film—microtubes and nanowires, and the two morphologies are randomly interwoven and distributed; Figure 2 (b) and (b1) show the high-magnification morphology and corresponding elemental distribution of the SiC microtubes; Figure 2 (c) and (c1) show the high-magnification morphology and corresponding elemental distribution of the SiC nanowires. This indicates that a flexible thin film with a dual morphology of SiC microtubes / SiC nanowires was successfully prepared.
[0041] Figure 3 The transmission electron microscope (TEM) images and corresponding elemental distribution maps of the flexible thin film prepared in Example 3 are further shown. Figure 3 (a) and (b) show the morphology and corresponding elemental distribution of SiC nanowires in the thin film. The SiC nanowires have smooth, cylindrical surfaces and uniform distribution of Si and C elements. Figure 3(c) Further, the high-magnification diffraction pattern and corresponding selected area electron diffraction pattern of the SiC nanowires are shown. The fringes are clearly visible, and there are bright diffraction spots, corresponding to β-SiC. This further proves that the SiC nanowires have been successfully prepared.
[0042] Figure 4 The results of high-temperature resistance tests on the flexible film prepared in Example 3 are shown. Figure 4 (a) and (b) show optical photographs of the film before and after heat treatment at 1400 °C. The results show that the film can still maintain its integrity after heat treatment at 1400 °C for 15 min, exhibiting excellent high-temperature resistance.
[0043] Example 4 This embodiment provides a method for synergistically preparing SiC microtube / SiC nanowire dual-morphology flexible thin films using powder and carbon template, including the following steps: (1) Tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid (1 mol / L), and deionized water are mixed evenly. The volume ratio of deionized water to tetraethoxysilane is 5:1; the mass ratio of tetraethoxysilane to hexadecyltrimethylammonium bromide is 370:1; and the volume ratio of deionized water to hydrochloric acid is 82:1. After mixing evenly, solution A is obtained. (2) Let solution A stand for 2 days to solidify, then grind it into powder B in a mortar; (3) Cut the thin carbon felt into dimensions of 80 mm in length, 20 mm in width, and 6 mm in thickness to obtain carbon felt C; (4) Spread powder B evenly in graphite paper with a thickness of 1.5 mm, then place carbon felt C on the powder and cover it with another layer of graphite paper. (5) The sample from step (4) above was placed in a high-temperature tubular heat treatment chamber for 2 hours. The temperature was set to 1550 °C and the argon pressure was 0.15 MPa. After the furnace cooled to room temperature, sample D was obtained. (6) Place sample D in a low-temperature oxidation furnace at 800 °C and oxidize it in air for 2 hours. After the low-temperature oxidation furnace cools to room temperature, take out the sample to obtain a large-size single-phase SiC nanowire refractory film.
[0044] Example 4 successfully prepared a flexible SiC microtube / SiC nanowire film, which withstood a high temperature of 1400 degrees Celsius for 15 minutes without damage.
[0045] Comparative Example 1 (1) Tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid (1 mol / L), and deionized water are mixed evenly. The volume ratio of deionized water to tetraethoxysilane is 2:1; the mass ratio of tetraethoxysilane to hexadecyltrimethylammonium bromide is 372:1; and the volume ratio of deionized water to hydrochloric acid is 80:1. After mixing evenly, solution A is obtained. (2) Let solution A stand for 1-2 days to solidify, then grind it into powder B in a mortar; (3) Spread powder B evenly in the graphite paper, and then cover it with another layer of graphite paper; (4) Place the sample from step (3) above in a high-temperature tubular heat treatment chamber for 1-3 hours. The temperature is set to 1500 ℃ and the argon gas pressure is 0.10 MPa. After the furnace cools to room temperature, sample D is obtained.
[0046] Figure 5 The experimental results of Comparative Example 1 are presented, showing that Comparative Example 1 failed to successfully prepare a flexible SiC microtube / SiC nanowire film. This comparative example did not fully follow the preparation process proposed in this invention, and therefore could not prepare a sample. Because the carbon felt design process in steps (3) and (4) of this invention was missing, a complete flexible SiC microtube / SiC nanowire film could not be prepared. Only a small amount of SiC nanowires could be obtained on the upper graphite paper, but the nanowires were few and could not form a film independently (see...). Figure 5 This illustrates that the design of thin carbon felt sheets is indispensable.
[0047] Comparative Example 2 (1) Tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid (1 mol / L), and deionized water are mixed evenly. The volume ratio of deionized water to tetraethoxysilane is 2:1; the mass ratio of tetraethoxysilane to hexadecyltrimethylammonium bromide is 372:1; and the volume ratio of deionized water to hydrochloric acid is 80:1. After mixing evenly, solution A is obtained. (2) Cut the thin carbon felt into dimensions of 90 mm in length, 30 mm in width, and 3-10 mm in thickness to obtain carbon felt B; (3) After soaking sample B in solution A for 2 hours, it was placed in a drying oven to dry it, thus obtaining sample C; (4) Sample C was placed in a high-temperature tubular heat treatment chamber for 2 hours. The temperature was set at 1500 °C and the argon gas pressure was 0.10 MPa. After the furnace cooled to room temperature, sample D was obtained. (5) Sample D was placed in a low-temperature oxidation furnace at 700 °C and oxidized in air for 2 hours. After the low-temperature oxidation furnace cooled to room temperature, the sample was taken out and a rigid and brittle material was obtained.
[0048] Figure 6 The experimental results of Comparative Example 2 are presented, showing that Comparative Example 2 failed to successfully prepare a flexible SiC microtube / SiC nanowire film. This comparative example did not fully follow the preparation process proposed in this invention, and therefore could not prepare a flexible SiC microtube / SiC nanowire film. This is because the high-temperature pyrolysis design process of the powder precursor proposed in steps (2) and (4) of this invention was missing, resulting in the inability to prepare a flexible film. Furthermore, when impregnation was used instead of powder sintering, only a rigid material was obtained, which was extremely prone to embrittlement and failure, lacking flexibility (see...). Figure 6 This illustrates that the design of the powder is particularly important and indispensable in the experimental process of this invention.
[0049] This invention achieves the simultaneous formation and preparation of SiC nanowires and SiC microtubes. Through the design of precursor powder grinding, a flexible film with dual morphology is prepared in one step. Thin carbon felt is selected as a carbon template. The role of the thin carbon felt is to provide a nucleation framework for the formation of SiC microtubes and to provide a carbon source for the growth of SiC nanowires.
[0050] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.
Claims
1. A method for synergistic preparation of a dual-morphology flexible thin film using powder and a carbon template, characterized in that, Includes the following steps: A solution was prepared by uniformly mixing tetraethoxysilane, hexadecyltrimethylammonium bromide, hydrochloric acid, and deionized water; the solution was then allowed to stand and solidify before being ground into precursor powder. Cut carbon felt sheets were placed on precursor powder and subjected to high-temperature heat treatment, followed by low-temperature oxidation treatment to obtain a flexible SiC microtube / SiC nanowire dual-morphology film.
2. The method for synergistic preparation of a dual-morphology flexible thin film using powder and carbon template according to claim 1, characterized in that, The volume ratio of deionized water to tetraethoxysilane is 2:1-5:1; the mass ratio of tetraethoxysilane to hexadecyltrimethylammonium bromide is 365:1-375:1; and the volume ratio of deionized water to hydrochloric acid is 75:1-85:
1.
3. The method for synergistic preparation of a dual-morphology flexible thin film using powder and carbon template according to claim 1, characterized in that, The concentration of the hydrochloric acid is 1 mol / L.
4. The method for synergistic preparation of a dual-morphology flexible thin film using powder and carbon template according to claim 1, characterized in that, The curing time is 1-2 days.
5. The method for synergistic preparation of a dual-morphology flexible thin film using powder and carbon template according to claim 1, characterized in that, The cut carbon felt sheets are 30-100 mm long, 10-40 mm wide, and 3-10 mm thick.
6. The method for synergistic preparation of a dual-morphology flexible thin film using powder and carbon template according to claim 1, characterized in that, The thickness of the precursor powder is 0.5-2 mm.
7. The method for synergistic preparation of a dual-morphology flexible thin film using powder and carbon template according to claim 1, characterized in that, The high-temperature heat treatment process is as follows: The precursor powder is evenly spread on graphite paper, and a thin sheet of carbon felt is placed on the precursor powder. Then, another layer of graphite paper is added, and the mixture is placed in a high-temperature tube heat treatment chamber and heat-treated at 1400-1600℃ for 1-3 hours in an argon atmosphere with a pressure of 0.05-0.20 MPa. The mixture is then cooled to room temperature.
8. The method for synergistic preparation of a dual-morphology flexible thin film using powder and carbon template according to claim 1, characterized in that, The low-temperature oxidation process is as follows: the product that has undergone high-temperature heat treatment is placed in a low-temperature oxidation furnace at 600-900 ℃ and oxidized in air for 1-4 hours, and then cooled to room temperature.
9. The dual-morphology flexible thin film prepared by the method of co-preparation of powder and carbon template as described in any one of claims 1 to 8, characterized in that, The dual-morphology flexible film is composed of SiC microtubes and SiC nanowires, which are randomly intertwined and wound together.
10. The dual-morphology flexible thin film according to claim 9, characterized in that, The dual-morphology flexible film can withstand a temperature of 1400 ℃ for up to 15 minutes in air without damage.