A ceramic aerogel fiber having a helically oriented array of nanowires and methods of making and using the same

Abstract

The application discloses a ceramic aerogel fiber with a nanowire structure in a spiral orientation arrangement, a preparation method and application thereof, and belongs to the technical field of advanced ceramic materials and special fibers. The ceramic aerogel fiber is constructed by ceramic nanowires, and the ceramic nanowires are arranged in a spiral orientation along the axial direction of the ceramic aerogel fiber. The application realizes efficient load transmission and stress dissipation through the spiral orientation arrangement structure, so that the fiber has excellent tensile strength and super flexibility while maintaining high porosity, the strength retention rate is high in a tight knot state, and the preparation process does not need a solvent, so that microstructure defects are avoided, and the application is suitable for the fields of flexible thermal protection and high-temperature thermal insulation.

Description

Technical Field

[0001] This invention belongs to the field of advanced ceramic preparation technology, specifically relating to a high-strength, ultra-flexible ceramic aerogel fiber with a helically oriented nanowire structure, its preparation method, and its application. Background Technology

[0002] Aerogel fibers combine the ultra-low density, high porosity, and low thermal conductivity of aerogels with the flexibility of one-dimensional fiber materials, enabling them to be bent, knotted, and woven into complex aerogel textiles. They show great promise for applications in thermal protection, aerospace insulation, and flexible electronic devices. However, due to the typically high porosity (over 90%), aerogel fibers have relatively low mechanical strength, making them prone to structural failure, especially under the tensile and knotting stresses of weaving. Currently, high-performance aerogel fibers are mostly based on organic polymers such as Kevlar and cellulose. The flexibility of the polymer chains in these polymers provides the fibers with a certain tensile strength and flexibility, but the polymers soften easily at high temperatures, resulting in poor thermal stability of the aerogel fibers. In contrast, ceramic aerogel fibers constructed from silica or titanium dioxide nanoparticles possess high-temperature resistance, but the nanoparticles rely on necking connections, resulting in weak bonding and a tensile strength only in the kilopascal range, severely limiting their practical applications.

[0003] One-dimensional ceramic nanowires (such as SiC and Si3N4) possess intrinsic tensile strengths of several gigapascals and exhibit good flexibility, making them ideal building blocks for high-performance ceramic aerogel fibers. The orientation of the nanowires within the fiber is a key factor determining its mechanical properties. Highly oriented nanowires enable effective transfer of external loads along the nanowire axis, thus fully utilizing their intrinsic high tensile strength; conversely, if the nanowires are randomly arranged, load transfer efficiency is low, leading to a significant reduction in fiber strength. Regarding preparation methods, existing aerogel fibers primarily employ wet spinning processes, but this process suffers from several problems: firstly, it requires the removal of large amounts of solvent, resulting in a complex and lengthy preparation process; secondly, the capillary forces generated during solvent removal can easily cause the porous structure to collapse, and it is difficult to effectively control the orientation of the nanowires, severely limiting the mechanical properties of the aerogel fibers. Therefore, how to fundamentally resolve the contradiction between high porosity and high strength and high flexibility in ceramic aerogel fibers through microstructure and preparation process design is a core technical challenge that urgently needs to be overcome by those skilled in the art. Summary of the Invention

[0004] To address the problem that existing ceramic aerogel fibers cannot simultaneously achieve high porosity, high strength, and high flexibility, the present invention aims to provide a high-strength, ultra-flexible ceramic aerogel fiber with a helically oriented nanowire structure, its preparation method, and its application, thereby achieving excellent tensile strength and flexibility while maintaining high porosity.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a ceramic aerogel fiber with a helically oriented nanowire structure, which is constructed from ceramic nanowires arranged in a helical orientation along the axial direction of the ceramic aerogel fiber body.

[0006] The helical arrangement of ceramic nanowires along the fiber axis enables efficient transmission of external loads along the nanowire axis, fully leveraging the intrinsic high strength of the ceramic nanowires. At the same time, the helical arrangement allows relative slippage and rearrangement between nanowires to dissipate local stress when the fiber is bent or knotted, giving the fiber excellent flexibility and thus achieving a synergy of high strength and ultra-flexibility.

[0007] Preferably, the helical angle of the helical orientation is 10° to 70°; the length of the ceramic nanowire is 500 μm to 5 cm, and the diameter is 50 to 800 nm. This scheme optimizes the specific parameter window of the helical angle and nanowire size. Within this range, the helical arrangement and size parameters of the nanowire are synergistically optimized, enabling the nanowire to effectively transfer loads and fully dissipate energy through relative slip during deformation. This is beneficial for obtaining higher tensile strength retention and better bending flexibility.

[0008] Preferably, the porosity of the ceramic aerogel fiber is 90% to 98%. Controlling the porosity within a high range ensures the thermal insulation performance of the fiber under extreme lightweight requirements. At the same time, this porosity range is compatible with the helical orientation structure, avoiding structural looseness due to excessive porosity or reduced flexibility due to excessively low porosity.

[0009] Preferably, the ceramic aerogel fiber has a tensile strength ≥80 MPa at room temperature; and the tensile strength retention rate of the ceramic aerogel fiber in a tightly knotted state is ≥99%. This application clearly quantifies the macroscopic mechanical properties of the fiber, verifies the effectiveness of the helical oriented nanowire structure under actual stress, and in particular, the extremely high knot strength retention rate indicates that the fiber overcomes the defects of traditional ceramic fibers, such as high brittleness and poor bending resistance, and meets the needs of textile processing and flexible applications.

[0010] As a preferred option, α-Si3N4 nanowires are selected for ceramic nanowires, and α-phase silicon nitride is used as the building block. By utilizing its excellent high-temperature stability and intrinsic mechanical properties, the resulting aerogel fibers can maintain or even improve their mechanical strength under high-temperature conditions, thus expanding their application potential in extreme thermal protection scenarios.

[0011] This invention also discloses a method for preparing the above-mentioned ceramic aerogel fibers with a helically oriented nanowire structure, comprising the following steps: A ceramic nanowire aerogel with a loose internal three-dimensional network structure and disordered nanowire distribution is selected. A traction wire is attached to the surface of the ceramic nanowire aerogel, and the traction wire forms a physical entanglement with the nanowires on the surface of the ceramic nanowire aerogel. A combined force of axial tension and circumferential rotation is applied to the traction wire simultaneously. Under the combined force, the physically entangled surface nanowires are pulled out in situ from the ceramic nanowire aerogel, and the disordered nanowires are rearranged in an oriented manner along the tension direction. Continuous stretching and rotation cause the nanowires to self-assemble and twist into ceramic aerogel fibers constructed from helically oriented nanowires.

[0012] The preparation method of this invention adopts a dry in-situ drawing and twisting process to extract nanowires from loose and disordered nanowire aerogels and induce their orientation and assembly. No solvent is required throughout the process, which fundamentally avoids the channel collapse and nanomaterial agglomeration defects caused by solvent removal in wet spinning, and ensures the integrity and uniformity of the microstructure of aerogel fibers. At the same time, through the combined mechanical field of axial drawing and circumferential torsion, the in-situ controllable reconstruction of nanowires from disorder to helical order is realized.

[0013] Preferably, by controlling the ratio of the circumferential rotation speed to the axial pulling speed, the helical angle of the helical orientation can be controlled. The larger the ratio, the larger the helical angle, and the more the arrangement direction of the ceramic nanowires tends to be perpendicular to the axial direction of the ceramic aerogel fiber; the smaller the ratio, the smaller the helical angle, and the more the arrangement direction of the ceramic nanowires tends to be parallel to the axial direction of the ceramic aerogel fiber.

[0014] More preferably, the circumferential rotation speed is 60-100 r / min, and the axial pulling speed is 5-10 mm / s.

[0015] Preferably, the density is ≤5 mg·cm³. -3 Ceramic nanowire aerogels with a porosity ≥ 99% were used as raw materials.

[0016] The present invention also discloses the application of the above-mentioned ceramic aerogel fibers with helically oriented nanowire structures in the preparation of flexible thermal protection or high-temperature thermal insulation aerogel products.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a ceramic aerogel fiber with a helically oriented nanowire structure. By constructing a microstructure in which ceramic nanowires are helically oriented along the fiber axis, the helical configuration causes the nanowires to gradually straighten and bear the main load during axial tension, achieving efficient axial stress transfer. During bending or knotting deformation, the space between the helical structure and nanowires allows for relative slippage and rearrangement, effectively dissipating localized stress concentration and preventing brittle fracture caused by localized stress concentration. The innovative structural design of this invention breaks the inherent contradiction between porosity and strength in ceramic materials, enabling the fiber to maintain a high porosity of 90%~98% while achieving a tensile strength of over 80 MPa at room temperature, and retaining ≥99% strength in a tightly knotted state. This meets the needs of flexible textiles and complex component molding, representing a 3 to 4 order of magnitude improvement over traditional aerogel fibers constructed with ceramic nanoparticles.

[0018] Furthermore, the ceramic aerogel fiber of this invention is composed of ceramic nanowires with a diameter of 50-800 nm. The ultra-fine diameter endows the nanowires with extremely high bending flexibility, while the helical orientation structure dissipates local stress during bending and deformation through relative slippage and rearrangement between the nanowires, avoiding stress concentration and breakage. This fiber can be repeatedly bent and knotted, and the strength retention rate after tight knotting is ≥99%. In contrast, traditional ceramic fibers (such as silicon oxide and silicon carbide) with a diameter of approximately 10 μm are extremely prone to breakage when knotted.

[0019] Furthermore, when α-Si3N4 nanowires are used as the basic building blocks, the tensile strength of the fibers obtained by this invention can reach more than 130 MPa at 700 °C, which is higher than the room temperature level.

[0020] This invention discloses a dry in-situ drawing and twisting process for preparing ceramic aerogel fibers with a helically oriented nanowire structure. Using loosely distributed, disordered nanowire aerogel as raw material, a composite mechanical field is applied through a flexible traction medium, causing the nanowires to be pulled out in situ and self-assemble into fibers in a solvent-free environment. This process completely avoids the defects of traditional wet spinning, such as pore collapse, shrinkage, and nanoparticle aggregation caused by capillary forces resulting from solvent evaporation. It preserves the high porosity of the aerogel and the intrinsic properties of the nanowires to the greatest extent, ensuring the uniformity and connectivity of the three-dimensional porous network inside the fiber.

[0021] Furthermore, a control mechanism for the ratio of helix angle to tension / rotation speed was established in the preparation method, which allows the orientation degree of nanowires to be continuously and precisely adjusted according to actual needs. This not only gives the production process a high degree of flexibility, but also provides a reliable technical means for developing differentiated aerogel fiber products for different working conditions (such as axially reinforced types that focus on load-bearing or radially fluffy types that focus on thermal insulation). Attached Figure Description

[0022] Figure 1 The above figures show silicon nitride nanowire aerogel raw materials used to prepare aerogel fibers. Figure a shows the macroscopic morphology of the aerogel, and Figure b shows the microscopic morphology.

[0023] Figure 2 This is a schematic diagram of the dry drawing and twisting spinning process.

[0024] Figure 3 The image shows the microstructure of the ceramic aerogel fibers prepared in Example 1.

[0025] Figure 4 The ceramic aerogel fiber prepared in Example 1 is shown in Figure a, where Figure a shows the microstructure of the knotted layer and Figure b shows the tensile stress-strain curves before and after knotting.

[0026] Figure 5 The image shows the microstructure of the ceramic aerogel fibers prepared in Example 2.

[0027] Figure 6 Tensile stress-strain curves of commercial silica ceramic fibers before and after knotting. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings: The preparation process of the ceramic aerogel fiber with a helical orientation nanowire structure described in this invention is shown in Figure 2, and specifically includes: First, ceramic nanowire aerogel with a loose internal three-dimensional network structure and disordered distribution of ceramic nanowires is selected as the raw material. A traction wire is attached to the surface of the ceramic nanowire aerogel, forming a physical entanglement between the traction wire and the surface ceramic nanowires. Then, a combined axial tension and circumferential torsion force are simultaneously applied to the traction wire. Under this combined force, the surface ceramic nanowires entangled with the traction wire are pulled out in situ from the ceramic nanowire aerogel matrix, and the originally disordered ceramic nanowires undergo directional rearrangement along the tension direction. By continuously maintaining the combined axial tension and circumferential torsion load, the directionally arranged ceramic nanowires self-assemble and twist together through interaction, ultimately producing continuous ceramic aerogel fibers constructed from helically oriented ceramic nanowires.

[0031] Example 1 This embodiment provides a method for preparing high-strength, ultra-flexible ceramic aerogel fibers with a helically oriented nanowire structure. The specific steps are as follows: 1) Preparation of nanowire aerogel raw materials α-Si3N4 nanowire aerogels were prepared using a chemical vapor deposition-like method, the specific method of which can be found in Chinese Patent ZL201810172223.4. The resulting α-Si3N4 nanowires had a size of 400–600 nm and a length of several centimeters; the density of the nanowire aerogel was 1 mg·cm³. -3 With a porosity of 99.9%, the nanowires are loosely packed together and can be pulled out and oriented when subjected to tension.

[0032] 2) Dry drawing spinning A single-strand cotton thread with a diameter of 0.1 mm was used as the traction thread. The traction thread was placed on the surface of α-Si3N4 nanowire aerogel and slightly rotated to create physical entanglement between the traction thread and the nanowires on the aerogel surface. The traction thread was then slowly stretched and rotated axially, with a rotation speed of 60 r / min and a stretching speed of 5 mm / s. Under the combined action of axial tension and circumferential torsion, the nanowires at the contact interface were pulled out of the aerogel in situ and rearranged from their initial disordered state to a highly oriented alignment along the stretching direction.

[0033] 3) Self-assembly and twisting into fibers As rotational tension continues, the highly oriented nanowires self-assemble and twist under the rotational action, forming a continuous aerogel fiber constructed from helically oriented nanowires.

[0034] See Figure 3Scanning electron microscopy revealed that the ceramic aerogel fibers were not simply stacked from traditional micrometer-scale continuous filaments or chopped fibers. Instead, they were constructed using ceramic nanowires as the basic building blocks, with the nanowires arranged in a helical orientation along the fiber axis to form a continuous one-dimensional fibrous macrostructure. Specifically, the nanowires inside the fibers were helically aligned along the fiber axis with a helix angle of approximately 30°, and the fiber diameter was approximately ~70 μm. The fiber density was 0.16 g·cm³. -3 Based on the density, the porosity is approximately 94.5%.

[0035] See Figure 4 The tensile strength of the fiber at room temperature was 100.7 ± 11.8 MPa, tested using a single-fiber tensile tester. More importantly, after the fiber was tied into a tight knot, the tensile strength retention rate was 99%. Figure 4 (b) From Figure 4 As shown in Figure a, the ceramic nanowires did not break in the extreme bending deformation region of the knot. Instead, they adapted to the large local strain by unwinding the spiral structure, the relative slippage between the nanowires, and the rearrangement of their positions, effectively avoiding stress concentration and exhibiting excellent flexibility.

[0036] Example 2 The preparation process in this embodiment is basically the same as that in Example 1, except that the ratio of rotational speed to pulling speed is adjusted to obtain different helix angles. Specifically, it includes the following steps: 1) Preparation of nanowire aerogel raw materials α-Si3N4 nanowire aerogels were prepared using a chemical vapor deposition-like method, the specific method of which can be found in Chinese Patent ZL201810172223.4. The obtained α-Si3N4 nanowires had a cross-sectional size of 400–600 nm and a length of several centimeters; the density of the nanowire aerogel was 1 mg·cm³. -3 With a porosity of 99.9%, the nanowires are loosely packed together and can be pulled out and oriented when subjected to tension.

[0037] 2) Dry drawing spinning A single-strand cotton thread with a diameter of 0.1 mm was used as the traction thread. The traction thread was gently touched to the surface of the α-Si3N4 nanowire aerogel, causing the traction thread to physically entangle with the nanowires on the aerogel surface. The traction thread was rotated and slowly pulled axially, with the rotation speed controlled at 120 r / min and the pulling speed at 5 mm / s. Under the combined action of axial tension and circumferential torsion, the nanowires at the contact interface were pulled out of the aerogel in situ and rearranged from their initial disordered state to a highly oriented alignment along the pulling direction.

[0038] 3) Self-assembly and twisting into fibers As rotational tension continues, the highly oriented nanowires self-assemble and twist under the rotational action, forming a continuous aerogel fiber constructed from helically oriented nanowires.

[0039] See Figure 5 Scanning electron microscopy revealed that the nanowires inside the obtained fibers were arranged in a helical orientation along the fiber axis, with a helix angle of approximately 70° (closer to the direction perpendicular to the fiber axis than in Example 1).

[0040] This embodiment illustrates the correlation between the speed ratio and the helix angle, which endows ceramic aerogel fibers with extremely high designability of microstructure. Specifically, when the application focuses on axial load-bearing capacity, a smaller helix angle can be obtained by reducing the speed ratio, allowing more ceramic nanowires to align along the direction of force, thereby maximizing tensile strength. Conversely, when the application focuses on axial thermal insulation performance or tensile ductility, a larger helix angle can be obtained by increasing the speed ratio, utilizing the unwinding of nanowires to improve the ductility of the aerogel fibers. This ability to reverse-engineer process parameters according to target performance requirements not only demonstrates the high controllability of the preparation method in this application but also provides solid technical support for the subsequent development of differentiated aerogel fiber products for different fields such as aerospace and flexible electronics.

[0041] Comparative Example Commercially available silica ceramic fiber bundles are selected. These bundles are composed of multiple continuous silica ceramic fibers and are widely used commercial products in fields such as high-temperature insulation and heat-resistant fabrics.

[0042] Commercial silica ceramic fiber bundles contain individual fibers composed of dense ceramic, with a diameter of approximately tens of micrometers and a smooth, dense surface. However, they lack the unique nanowire porous network structure and helical orientation of the ceramic nanowires characteristic of the ceramic aerogel fibers obtained in this application. In contrast, the aerogel fibers obtained in Example 1 of this invention are constructed from ceramic nanowires with a diameter of 50-800 nm, and the diameter of their building units is 1-2 orders of magnitude smaller than that of commercial silica ceramic fibers.

[0043] A commercial silica ceramic fiber bundle was tied into a loose knot and then subjected to a tensile test. The tensile stress-strain curves before and after knotting are shown below. Figure 6 As shown, the test results indicate that the fiber breaks rapidly at the knot during the stretching process, with a tensile strength retention rate of only 0.7% in the knotted state. The main reason for this is the large diameter of the individual silica fibers, which leads to extreme bending strain and stress concentration on the fiber surface during knotting and bending. Simultaneously, the dense ceramic structure cannot dissipate energy through internal slippage or deformation, causing the fiber to easily break at the knot. This result demonstrates that although commercially available silica ceramic fibers possess high intrinsic tensile strength, their actual load-bearing capacity is almost completely lost when faced with complex deformation conditions such as bending and knotting.

[0044] Further analysis of the failure mechanism reveals that the root cause of this brittle fracture lies in its microstructure and size effect. On the one hand, the single filament diameter of commercial silica ceramic fiber bundles reaches the micrometer level. Under the same radius of curvature, the bending strain on the fiber surface is proportional to the diameter. Therefore, at the tiny radius of curvature formed by knotting, the fiber surface will generate extremely large tensile strains, far exceeding the elastic limit of ceramic materials. On the other hand, the dense ceramic structure lacks movable interfaces or pore buffer spaces. When local stress concentration exceeds the critical value, once a crack is formed, it will rapidly propagate and penetrate the entire cross-section, unable to dissipate energy through internal plastic deformation or structural rearrangement. In contrast, the ceramic aerogel fibers prepared in Example 1 of this application are constructed from ceramic nanowires with a diameter of only 400-600 nm. The diameter of their building blocks is one to two orders of magnitude smaller than that of commercial fibers, significantly reducing bending stiffness and surface strain. More importantly, the unique helical orientation structure of this application endows the fibers with extremely high degrees of freedom. During knotting and deformation, the ceramic nanowires can adapt to local geometric constraints through relative sliding, rotation, and rearrangement, transforming the originally concentrated destructive stress into dispersed frictional dissipation energy, thereby avoiding brittle fracture. These comparative results fully demonstrate that this application, by constructing a specific microscopic topological structure in which ceramic nanowires are arranged in a helical orientation along the axial direction, fundamentally changes the mechanical response mode of ceramic materials, achieving a transformation from rigid brittle fracture to flexible deformation.

[0045] In summary, the ceramic aerogel fibers obtained using the method disclosed in this invention have the following beneficial effects: 1. By constructing a nanowire structure with a helical orientation, the nanowires gradually straighten under axial tension, achieving efficient axial load-bearing capacity. Simultaneously, the helical arrangement promotes radial densification of the nanowires, enhancing interfacial friction and mechanical interlocking between them, thus ensuring uniform stress distribution. The fibers prepared using this invention exhibit a room-temperature tensile strength of no less than 80 MPa, which is 3 to 4 orders of magnitude higher than that of traditional aerogel fibers constructed with ceramic nanoparticles.

[0046] 2. The ceramic aerogel fiber of this invention is composed of ceramic nanowires with a diameter of 50-800 nm. The ultra-fine diameter endows the nanowires with extremely high bending flexibility, while the helical orientation structure dissipates local stress during bending and deformation through relative slippage and rearrangement between the nanowires, avoiding stress concentration and breakage. This fiber can be repeatedly bent and knotted, and the strength retention rate after tight knotting is ≥99%. In contrast, traditional ceramic fibers (such as silicon oxide and silicon carbide) with a diameter of about 10 μm are extremely prone to breakage when knotted.

[0047] 3. When α-Si3N4 nanowires are used as the basic building blocks, the tensile strength of the fibers obtained by this invention can reach more than 130 MPa at 700 °C, which is higher than the room temperature level.

[0048] 4. This invention directly extracts nanowires from ultra-low density nanowire aerogel, orients them, and twists them into fibers, thus avoiding the pore structure collapse and nanomaterial aggregation defects caused by solvent removal during wet spinning.

[0049] 5. The porosity of the fiber of this invention is as high as 90%~98%. While achieving high strength, it still maintains the essential characteristics of aerogel materials such as ultralight weight and high porosity, making it suitable for applications such as flexible thermal protection and high-temperature insulation.

[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 ceramic aerogel fiber with a helically oriented nanowire structure, characterized in that, It is constructed from ceramic nanowires, which are arranged in a helical orientation along the axial direction of the ceramic aerogel fiber body.

2. The ceramic aerogel fiber with a helically oriented nanowire structure according to claim 1, characterized in that, The helical angle of the spiral orientation is 10°~70°; the length of the ceramic nanowire is 500 μm~5 cm and the diameter is 50~800 nm.

3. The ceramic aerogel fiber with a helically oriented nanowire structure according to claim 1, characterized in that, The porosity of the ceramic aerogel fiber is 90%~98%.

4. The ceramic aerogel fiber with a helically oriented nanowire structure according to claim 1, characterized in that, The ceramic aerogel fiber has a tensile strength ≥80 MPa at room temperature; the tensile strength retention rate of the ceramic aerogel fiber in the tightly knotted state is ≥99%.

5. The ceramic aerogel fiber with a helically oriented nanowire structure according to any one of claims 1-4, characterized in that, The ceramic nanowires selected are α-Si3N4 nanowires.

6. A method for preparing ceramic aerogel fibers with a helically oriented nanowire structure as described in any one of claims 1-5, characterized in that, Includes the following steps: A ceramic nanowire aerogel with a loose internal three-dimensional network structure and disordered nanowire distribution is selected. A traction wire is attached to the surface of the ceramic nanowire aerogel, and the traction wire forms a physical entanglement with the nanowires on the surface of the ceramic nanowire aerogel. A combined force of axial tension and circumferential rotation is applied to the traction wire simultaneously. Under the combined force, the physically entangled surface nanowires are pulled out in situ from the ceramic nanowire aerogel, and the disordered nanowires are rearranged in an oriented manner along the tension direction. Continuous stretching and rotation cause the nanowires to self-assemble and twist into ceramic aerogel fibers constructed from helically oriented nanowires.

7. The method for preparing ceramic aerogel fibers with a helically oriented nanowire structure according to claim 6, characterized in that, By controlling the ratio of the circumferential rotation speed to the axial pulling speed, the helix angle of the helical orientation can be controlled, and the larger the ratio, the larger the helix angle.

8. The method for preparing ceramic aerogel fibers with a helically oriented nanowire structure according to claim 7, characterized in that, The circumferential rotation speed is 60-100 r / min, and the axial pulling speed is 5-10 mm / s.

9. The method for preparing ceramic aerogel fibers with a helically oriented nanowire structure according to claim 6, characterized in that, Choose a density ≤ 5 mg·cm³ -3 Ceramic nanowire aerogels with a porosity ≥ 99% were used as raw materials.

10. The application of ceramic aerogel fibers with a helically oriented nanowire structure as described in any one of claims 1-5 in the preparation of flexible thermal protection or high-temperature thermal insulation aerogel products.

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