Search

CN-121974657-A - High-flexibility low-thermal-conductivity SiC-ZrC ceramic fiber aerogel and preparation method thereof

CN121974657ACN 121974657 ACN121974657 ACN 121974657ACN-121974657-A

Abstract

The invention provides a high-flexibility low-thermal-conductivity SiC-ZrC ceramic fiber aerogel and a preparation method thereof, and relates to the field of aerogel materials; the method comprises the steps of preparing spinning solution containing a silicon precursor, a zirconium precursor and polyvinylpyrrolidone, and performing electrostatic spinning, pre-oxidation and heat treatment to obtain the SiC-ZrC ceramic fiber aerogel with a three-dimensional fiber network structure through one-step SiC and ZrC fiber ceramization, wherein the diameter of the fiber in the aerogel is nano-scale, and the microstructure comprises a SiC nanofiber matrix and uniformly distributed ZrC nano particles. According to the method, the content of the zirconium precursor, the spinning parameters and the heat treatment parameters are regulated, the fiber morphology and the aerogel performance are accurately controlled, and the SiC-ZrC ceramic fiber aerogel with excellent mechanical properties and heat insulation performance is finally prepared, and the method is simple in process, good in controllability, high in repeatability and suitable for large-scale production.

Inventors

  • HU XIAOYE
  • DONG WENXIU
  • YU JIE
  • LI SHUXIN
  • HUANG ZHULIN
  • LI MING

Assignees

  • 中国科学院合肥物质科学研究院

Dates

Publication Date
20260505
Application Date
20260206

Claims (10)

  1. 1. The SiC-ZrC ceramic fiber aerogel with high flexibility and low thermal conductivity is characterized in that the SiC-ZrC ceramic fiber aerogel is microscopically in a three-dimensional fiber network structure, and the diameter of fibers in the three-dimensional fiber network structure is 500-1000 nm; the fiber is obtained by carrying out electrostatic spinning on raw materials containing a silicon precursor, a zirconium precursor and polyvinylpyrrolidone and then carrying out heat treatment, and the microstructure of the fiber comprises a SiC nanofiber matrix and ZrC nano particles which are uniformly distributed in the SiC nanofiber matrix and formed by in-situ recombination.
  2. 2. The high-flexibility low-thermal-conductivity SiC-ZrC ceramic fiber aerogel according to claim 1, wherein the thermal conductivity of the SiC-ZrC ceramic fiber aerogel is 0.012-0.11W/m.K.
  3. 3. The high-flexibility low-thermal-conductivity SiC-ZrC ceramic fiber aerogel according to claim 1, wherein the maximum compressive stress of the SiC-ZrC ceramic fiber aerogel under 80% strain is 60-72 KPa; The SiC-ZrC ceramic fiber aerogel is subjected to 100 fatigue tests under the condition that the strain is 50%, and the maximum stress of the SiC-ZrC ceramic fiber aerogel is not lower than 78% of the initial maximum stress value.
  4. 4. The preparation method of the SiC-ZrC ceramic fiber aerogel with high flexibility and low thermal conductivity is characterized by comprising the following steps: s1, providing a spinning solution, wherein the spinning solution comprises a silicon precursor, a zirconium precursor and polyvinylpyrrolidone; s2, carrying out electrostatic spinning on the spinning solution to obtain a precursor fiber membrane with a three-dimensional fiber network structure; S3, carrying out pre-oxidation treatment on the precursor fiber membrane after vacuum drying to obtain a pre-oxidized fiber membrane; S4, stacking the pre-oxidized fiber films layer by layer and then performing heat treatment to obtain the SiC-ZrC ceramic fiber aerogel.
  5. 5. The method for preparing the SiC-ZrC ceramic fiber aerogel with high flexibility and low thermal conductivity according to claim 4, wherein the silicon precursor is polycarbosilane, and the zirconium precursor is soluble metal zirconium salt selected from zirconium acetylacetonate.
  6. 6. The method for preparing the high-flexibility low-thermal-conductivity SiC-ZrC ceramic fiber aerogel according to claim 4, wherein the spinning solution further comprises an organic solvent, and the organic solvent is a mixed solvent of N, N-dimethylformamide and tetrahydrofuran.
  7. 7. The method for preparing the high-flexibility low-thermal-conductivity SiC-ZrC ceramic fiber aerogel according to claim 6, wherein the preparation process of the spinning solution is as follows: Preparing a first solution, wherein the first solution is obtained by dissolving a silicon precursor and polyvinylpyrrolidone by the mixed solvent; preparing a spinning solution, wherein the spinning solution is obtained by dissolving a zirconium precursor in the first solution under the stirring condition, the stirring speed is 400-600 rpm, and the stirring time is 4-6 h; the spinning solution comprises a mixed solvent and relative to the mass of the mixed solvent, the components comprise 10 wt% of silicon precursor, 8% wt% of polyvinylpyrrolidone and 0-5% of zirconium precursor.
  8. 8. The method for preparing the high-flexibility low-thermal-conductivity SiC-ZrC ceramic fiber aerogel according to claim 4, wherein in step S3, the conditions for performing the pre-oxidation treatment after the precursor fiber film is vacuum-dried are as follows: the precursor fiber film is firstly placed in a vacuum environment at 70-100 ℃ for drying for 12-24 hours, then placed in a blast drying oven at 80-110 ℃ for curing for 12-24 hours, and finally placed in an oven at 180-220 ℃ for pre-oxidation for 12-24 hours.
  9. 9. The method for preparing the high-flexibility low-thermal conductivity SiC-ZrC ceramic fiber aerogel according to claim 4, wherein in step S4, the conditions for performing the heat treatment on the pre-oxidized fiber film are as follows: And heating to 1400-1600 ℃ at the calcining heating rate of 2-5 ℃ per minute under the inert protective atmosphere with the gas flow rate of 180-250 mL/min, and carrying out thermal insulation pyrolysis for 60-150 min.
  10. 10. Use of the high flexibility low thermal conductivity SiC-ZrC ceramic fiber aerogel according to any one of claims 1 to 3 or the high flexibility low thermal conductivity SiC-ZrC ceramic fiber aerogel prepared by the method for preparing the high flexibility low thermal conductivity SiC-ZrC ceramic fiber aerogel according to any one of claims 4 to 9 in the field of high temperature insulation.

Description

High-flexibility low-thermal-conductivity SiC-ZrC ceramic fiber aerogel and preparation method thereof Technical Field The invention relates to the technical field of aerogel materials, in particular to a high-flexibility low-thermal conductivity SiC-ZrC ceramic fiber aerogel and a preparation method thereof. Background With the rapid development of aerospace technology, hypersonic aircrafts, reusable aircrafts and other equipment have placed extreme demands on thermal protection systems. Critical parts such as a windward side, a wing front edge and the like of the aircraft face severe pneumatic heating in the high-speed flight process, and the working environment is extremely bad. Therefore, development of a novel thermal protection material capable of stably working for a long period of time under such extreme conditions, while having excellent high temperature resistance, good flexibility, a certain deformation adaptability and anti-fatigue properties, has become an important development direction in the field. Ceramic aerogels, particularly silicon carbide (SiC) aerogels, are considered as one of the most potential material systems for handling the above extreme thermal environments due to their excellent high temperature stability, excellent oxidation resistance, high chemical inertness, and intrinsically excellent thermal insulation properties. However, when the traditional or existing majority of SiC aerogel is applied to actual engineering, two related core problems still exist, namely, firstly, the inherent brittleness causes poor mechanical properties of materials, and the requirements of deformation and damage resistance under complex surface lamination, vibration impact or repeated thermal cycling are difficult to meet, secondly, difficulties exist in maintaining the mechanical properties and ultralow thermal conductivity balance of the materials, and the low thermal conductivity is the key of efficient heat insulation. The prior research results prove the problems. For example, three-dimensional SiC aerogels have been prepared by growing SiC nanowires in situ using biomass-derived porous carbon as a template, which, while exhibiting relatively low thermal conductivity (about 0.035W/mK) and high porosity (about 97.6%), are significantly brittle, less elastic, and less susceptible to mechanical deformation. In addition, the preparation of the full ceramic SiC aerogel by combining freezing casting and carbothermal reduction technology has been studied, the thermal conductivity (about 0.05W/m.K) obtained by the full ceramic SiC aerogel is still higher, the heat insulation performance is further improved, and the mechanical flexibility problem is not solved effectively. To address these challenges, current technological ideas focus on improving material performance through fine composition and structural design. For example, the introduction of heterogeneous elements into the material to build up a rich heterogeneous interface, or the intentional preservation of partially amorphous morphology to inhibit overgrowth of crystalline particles, these strategies aim at simultaneously increasing the flexibility and further reducing the thermal conductivity of SiC-based aerogels. In terms of the preparation process, the approaches which can be used for obtaining the ceramic fiber aerogel mainly comprise a self-assembly method, a melt spinning method, an atomic layer deposition method, an electrostatic spinning method and the like. However, these methods have limitations in that the self-assembly process is sensitive to environmental conditions, has poor controllability and is difficult to mass production, the melt spinning process has extremely severe requirements on the raw material system and the process temperature, and the atomic layer deposition process can realize precise nano-layer control, but has slow deposition rate, high cost and high requirements on equipment, and is unfavorable for efficient preparation. Therefore, on the basis of ensuring excellent high temperature resistance and heat insulation characteristics of the SiC material, the brittleness problem is effectively solved and lower heat conductivity is obtained through an innovative material design and preparation process, so that the flexible high-efficiency heat insulation material with comprehensive performance meeting the requirements of the next-generation aerospace aircraft is developed, and the key technical problem to be broken through in the field is still urgent. Disclosure of Invention 1. Technical problem to be solved by the invention The prior art focuses on improving the performance of SiC aerogel through fine components and structural design, and can improve the heat insulation performance by obtaining low heat conductivity, but the mechanical performance cannot be balanced with ultra-low heat conductivity, and the technical situations of poor mechanical performance and easy denaturation damage of the SiC aerogel cannot be