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CN-121974720-A - Flexible silicon modified zirconia fiber aerogel material for long-term high-efficiency heat protection and preparation method thereof

CN121974720ACN 121974720 ACN121974720 ACN 121974720ACN-121974720-A

Abstract

The invention discloses a flexible silicon modified zirconia fiber aerogel material for long-term efficient heat protection and a preparation method thereof, belonging to the technical field of structural ceramics and heat insulation materials. The method comprises the steps of taking zirconium chloride and yttrium chloride as raw materials, taking acetylacetone as a chelating agent, synthesizing yttrium-stabilized zirconia precursor powder, blending the powder with a silane coupling agent (the molar ratio of silicon to zirconium is 0.05-0.2:1) and a spinning aid in a specific ratio to obtain spinning solution, carrying out electrostatic spinning to obtain precursor fiber aerogel, and carrying out sectional heat treatment to obtain a final product. The prepared ceramic fiber has a unique core-shell structure, wherein the fiber core part of the ceramic fiber is uniformly distributed with dispersed nano holes, the outer layer is a compact shell layer, and silicon elements are mainly enriched in crystal boundaries. The structure enables the material to have excellent flexibility (such as complete rebound under 98% compression strain) and extremely low high temperature conductivity (about 0.083W/m.K at 1000 ℃), and simultaneously silicon doping effectively inhibits growth of high Wen Jingli. The material has wide application prospect in the extreme environment fields such as high-temperature heat insulation, aerospace heat protection and the like.

Inventors

  • ZHANG YONGSHENG
  • SU YUNFENG
  • FAN HENGZHONG
  • ZHU XIAOXIA
  • ZHANG QIANGQIANG
  • MA XIAOLI
  • FENG YAOFEI
  • HA HAIRONG
  • ZHOU JIANSONG
  • Yue Difan

Assignees

  • 中国科学院兰州化学物理研究所
  • 中国船舶重工集团公司第七0五研究所

Dates

Publication Date
20260505
Application Date
20260209

Claims (10)

  1. 1. The preparation method of the flexible silicon modified zirconia fiber aerogel material for long-term high-efficiency heat protection is characterized by comprising the following steps of: (1) Preparing precursor powder, namely taking zirconium chloride as a zirconium source, taking yttrium chloride as a stabilizer, dissolving the zirconium chloride in absolute methanol, sequentially adding acetylacetone and triethylamine after the yttrium chloride is completely dissolved, and stirring and reacting to obtain golden yellow reaction solution; (2) Preparing a spinning solution, namely dissolving the precursor powder obtained in the step (1), a silane coupling agent and a spinning aid in anhydrous methanol, and stirring to obtain the spinning solution; (3) And (3) electrostatic spinning and heat treatment, namely performing electrostatic spinning on the spinning solution obtained in the step (2) to obtain precursor fiber aerogel, and performing heat treatment on the precursor fiber aerogel to obtain silicon modified zirconia ceramic fiber aerogel with the dispersed nano-pore core-shell structure, wherein silicon element in the silicon modified zirconia ceramic fiber aerogel exists in a mode of wrapping zirconia grains and dispersing in the grains, the fiber has a core-shell structure, and the inside of the fiber is provided with dispersed nano-pores.
  2. 2. The method according to claim 1, wherein in the step (1), the molar ratio of yttrium chloride to zirconium chloride is 3:97, and the molar ratio of zirconium source, acetylacetone to triethylamine is 1 (0.9-1.1): 2-3.
  3. 3. The method according to claim 1, wherein in the step (1), the acetylacetone and the triethylamine are added by slow dropping or atomizing.
  4. 4. The method according to claim 1, wherein in the step (2), the mass ratio of the silane coupling agent, the precursor powder and the anhydrous methanol is (0.03 to 0.25): 1 (1.03 to 1.25).
  5. 5. The method according to claim 1, wherein in the step (2), the spinning aid is polyethylene oxide or polyvinylpyrrolidone, and the mass of the spinning aid is 0.05% -0.15% of the mass of the anhydrous methanol.
  6. 6. The method according to claim 1, wherein in the step (2), the stirring temperature at the time of preparing the spinning solution is 40 ℃ to 70 ℃.
  7. 7. The preparation method of the electrostatic spinning device according to claim 1, wherein in the step (3), the condition of electrostatic spinning is that the environment relative humidity is 45% -60%, the temperature is 20% -30 ℃, the spinning voltage is 15-20 kV, the receiving distance is 20-40 cm, and the advancing speed of a spinning solution is 0.8-2.5 mL/h.
  8. 8. The method according to claim 1, wherein in the step (3), the heat treatment process comprises heating to 800-1000 ℃ at a rate of 1-5 ℃ per minute, heating to 1000-1450 ℃ at a rate of 5-20 ℃ per minute, maintaining for 20-120 min, and cooling in a furnace.
  9. 9. The flexible silicon modified zirconia fiber aerogel material prepared by the preparation method of any one of claims 1 to 8 is characterized by being of a three-dimensional network-shaped and self-supporting porous fiber aerogel structure, wherein silicon modified zirconia ceramic fibers are mutually curled and wound and lapped to form a communicated pore skeleton, the ceramic fibers are a yttrium oxide stabilized zirconia and silicon composite system, the molar ratio of silicon to zirconium is 0.05-0.2:1, the ceramic fibers are of a core-shell structure along the radial direction, the outer layer is of a continuous relatively compact shell layer, and the core part contains uniformly distributed dispersed nanopores.
  10. 10. Use of the flexible silicon-modified zirconia fiber aerogel material of claim 9 in structural function materials, high temperature insulation flexible materials, extreme environment resistant materials, or aerospace applications.

Description

Flexible silicon modified zirconia fiber aerogel material for long-term high-efficiency heat protection and preparation method thereof Technical Field The invention relates to a silicon modified zirconia ceramic fiber material, in particular to a flexible ceramic fiber aerogel with a dispersed nano-pore core-shell structure and a preparation method thereof, belonging to the technical field of preparation of structural ceramics and heat-insulating ceramic fiber materials. Background Ceramic fiber materials have long received wide attention in the fields of high temperature insulation, energy, aerospace, microelectronics, novel energy conversion, and the like due to their excellent high temperature stability, low thermal conductivity, corrosion resistance, and higher specific surface area. The zirconia (ZrO 2) is used as an important structural ceramic material, has high melting point, low thermal conductivity and good thermal shock stability, and has wide application prospect in heat insulation protection, catalytic carriers and electrochemical devices. However, the problems of high fiber brittleness, easy grain growth after high-temperature heat treatment, pore collapse, limited flexibility and heat insulation performance and the like of the traditional zirconia ceramic fiber generally exist in the preparation process, and the popularization and the application of the traditional zirconia ceramic fiber in an extreme service environment are limited to a certain extent. As an effective method for preparing nano/micron fibers, the electrostatic spinning can realize the multi-component doping with good fiber continuity and controllable diameter. However, most of the existing zirconia-based electrostatic spinning fibers have solid structures, the porosity is limited, the pore structures are not adjustable, grain growth easily occurs after high-temperature treatment, the specific surface is greatly reduced, the thermal conductivity is increased, good heat insulation performance and mechanical flexibility are difficult to be achieved, and finally the material performance is greatly attenuated. To ameliorate the above problems, researchers have attempted to optimize fiber properties through heterogeneous atomic doping or structural design. For example, the silicon element is introduced to form a silica network in the zirconia ceramic fiber, which is helpful for inhibiting the growth of crystal grains, enhancing the structural stability and improving the flexibility and the high-temperature thermal shock resistance of the fiber to a certain extent. In addition, the construction of core-shell structures, porous structures, or composite phase interfaces is also considered as an effective way to achieve the lightening and efficient thermal insulation properties of ceramic fibers. Especially, the core-shell fiber has the advantages that the shell layer can provide support and toughness, and the porous structure of the core part can obviously reduce the heat conductivity of the material, so that the cooperative optimization of heat insulation and mechanical property is realized. The literature "j. Alloy. Compact, 2023, 173165" studied the effect of yttria doped (Y 2O3) on the phase composition, grain evolution and mechanical properties of continuous zirconia fibers, and found that proper incorporation of Y 2O3 can stabilize the high temperature phase (tetragonal/cubic) of zirconia, inhibit the phase transition from single phase to low temperature monoclinic phase and reduce the grain growth rate, thereby maintaining better mechanical strength and structural integrity at high temperatures, and was considered as one of the most promising high temperature structural and thermal insulating ceramic fibers. However, the document also states that under extremely high temperatures (. Gtoreq.1200-1500 ℃) or long-term thermal cycling conditions, segregation and grain boundary evolution of Y 3+ at the interface still cause local fluctuations in phase stability, and that such Y-doped fibers are usually of dense or microporous structure, which makes it difficult to directly compromise extremely low thermal conductivity with flexibility. In addition, the document 'Preparation of fine-GRAINED SILICA-doped zirconia fibers by electrospinning' researches the introduction of silicon into zirconia fiber, and finds that the Si doping can effectively inhibit the growth of crystal grains, so that the crystal grain size is controlled to be 30-60 nm, and the fiber diameter is 400-700 nm, however, the silicon doped zirconia fiber in the document is still mainly of a solid structure or is only provided with micropores, and has insufficient flexibility and deformation recovery. Therefore, how to further improve the high-temperature heat insulation, mechanical strength and flexibility of zirconia fiber or ceramic fiber aerogel has become a problem to be solved in the field of space-electrode environment. Disclosure of Invention Aiming at the technic