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CN-121976326-A - Preparation method of silicon carbide micron-sized sponge based on heating regulation strategy

CN121976326ACN 121976326 ACN121976326 ACN 121976326ACN-121976326-A

Abstract

The invention belongs to the technical field of silicon carbide porous materials, and provides a preparation method of a silicon carbide micron-sized band sponge based on a heating regulation strategy. The method comprises the steps of taking a porous template containing carbon fibers as a framework, taking a silicon source as a reaction precursor, forming a SiC/SiOx composite shell layer attached to the surface of the carbon fibers through high-temperature reaction, then carrying out controlled heat treatment under an air atmosphere to gradually oxidize and consume the carbon fibers, inducing the SiC/SiOx shell layer to crack along the length direction of the fibers and convert into a porous micron-sized belt structure, and thus obtaining the three-dimensional porous network sponge material with the silicon carbide micron-sized belt as a main structural unit. The target micron band structure can be stably obtained by controlling the high-temperature reaction temperature and the air heat treatment time window, and the obtained material has the performances of high porosity, low density, low heat conduction, flexibility, compressibility and electromagnetic wave absorption, and is suitable for heat insulation and electromagnetic protection integrated application in extreme environments.

Inventors

  • YAN MINGYUAN
  • NIE SHIBIN
  • CAO CHENGFEI
  • WANG JINGWEN

Assignees

  • 安徽理工大学

Dates

Publication Date
20260505
Application Date
20260403

Claims (7)

  1. 1. The preparation method of the silicon carbide micron-sized band sponge based on the heating regulation strategy is characterized by comprising the following steps of: (1) Providing a porous template containing carbon fibers and preparing a silicon source raw material; (2) Placing the porous template and a silicon source in a reaction environment to perform high-temperature reaction, so that silicon-containing active species are deposited and react on the surface of the carbon fiber to form a SiC/SiOx composite shell layer attached to the surface of the carbon fiber, and obtaining a precursor; (3) And (3) carrying out heat treatment on the precursor obtained in the step (2) in an air atmosphere, gradually oxidizing and consuming carbon fibers by oxygen, removing redundant carbon, inducing the SiC/SiOx composite shell layer to crack along the length direction of the fibers, forming a porous micron belt structure, and finally obtaining the silicon carbide micron belt sponge.
  2. 2. The method of claim 1, wherein in step (1), the silicon source is a mixture of silicon powder and silicon dioxide powder, or is a silicon oxide powder.
  3. 3. The method according to claim 1, wherein in the step (1), the porous template is a carbon fiber felt with a thickness of 1-10 mm.
  4. 4. The preparation method according to claim 1, wherein in the step (2), the high-temperature reaction is performed at a temperature of 1200-1300 ℃, the heating rate is 5-15 ℃ per minute, the heat preservation time is 10-180 min, and the reaction environment is an inert gas environment.
  5. 5. The preparation method according to claim 1, wherein in the step (3), the temperature of the heat treatment is 650 ℃ to 850 ℃ and the heat preservation time is 30 to 90 minutes.
  6. 6. A silicon carbide micron-sized sponge made by the method of any one of claims 1-5.
  7. 7. The silicon carbide micron belt sponge according to claim 6, wherein the silicon carbide micron belt sponge meets one or more of the following structural characteristics, wherein the characteristic width of the micron belt is 1.0-4.0 μm, the surface of the micron belt is provided with cracks and/or holes, the micron belt is formed by compositing crystalline SiC and amorphous SiOx, and a SiC/SiOx hetero-interface structure is formed between the crystalline SiC and the amorphous SiOx.

Description

Preparation method of silicon carbide micron-sized sponge based on heating regulation strategy Technical Field The invention belongs to the technical field of silicon carbide porous materials, and particularly relates to a preparation method of a silicon carbide micron-sized band sponge based on a heating regulation strategy. Background With the development of the front-edge fields such as deep-ground exploration, deep space exploration and the like, an extremely high-temperature service environment provides a strict requirement on the heat protection and electromagnetic anti-interference integrated performance of the device. Silicon carbide (SiC) porous materials are preferred candidates in this field by virtue of their inherent properties of high temperature resistance, low thermal conductivity, and electromagnetic wave absorption. However, the traditional SiC porous material has single microstructure unit and is formed by piling necklace-shaped nano particles, has the inherent defects of high brittleness and easy fragmentation, is difficult to bear repeated mechanical deformation such as compression, bending and the like, and severely restricts the practical engineering application in severe extreme environments. Under the background, development of a SiC porous material which can realize accurate and controllable construction of a microstructure, has excellent flexibility and capability of recovering compression deformation, and integrates high-efficiency heat insulation and electromagnetic wave absorption comprehensive performance, and a preparation method thereof have become key problems to be broken through in the field. Disclosure of Invention In view of the above, the invention aims to provide a preparation method of a silicon carbide micron-sized band sponge based on a heating regulation strategy, which aims to solve the technical problems of single structural unit, large brittleness, insufficient flexibility and insufficient compressibility of the existing silicon carbide porous material, and solve the problems that the microstructure is difficult to accurately control construction and cannot be stably and repeatedly prepared, so that the silicon carbide porous material with the advantages of structural regulation and comprehensive performance is obtained, and the application requirements under extreme environments are met. The invention adopts the following technical scheme for realizing the purpose: A preparation method of a silicon carbide micron-sized band sponge based on a heating regulation strategy comprises the following steps: (1) Providing a porous template containing carbon fibers and preparing a silicon source raw material; (2) The porous template and a silicon source are placed in a reaction environment to perform high-temperature reaction, silicon-containing active species are deposited and react on the surface of the carbon fiber to form a SiC/SiOx composite shell layer attached to the surface of the carbon fiber, a precursor is obtained, si in the silicon source and SiO 2 are reacted to generate SiO gas or SiO gas is formed by silicon oxide in the high-temperature reaction process, siO is taken as a key silicon-containing active species to diffuse to the surface of the carbon fiber and is preferentially adsorbed on the surface of the carbon fiber, the adsorbed SiO can directly react with active carbon on the surface of the carbon fiber to form SiC crystal nuclei, generated CO is further diffused into a local reaction atmosphere, and on the other hand, siO and CO near a gas phase or interface can continuously react with the formed SiC crystal nuclei/the surface of the carbon fiber to promote continuous growth of the SiC crystal nuclei and gradually form continuous shell layers. At the same time, partially incompletely carbonized silicon-containing species or metastable silicon oxides deposited during subsequent cooling remain in the shell, thereby forming a SiC/SiOx composite shell. (3) And (3) carrying out heat treatment on the precursor obtained in the step (2) in an air atmosphere, gradually oxidizing and consuming carbon fibers by oxygen, removing redundant carbon, inducing the SiC/SiOx composite shell layer to crack along the length direction of the fibers to form a porous micron belt structure, and finally obtaining the silicon carbide micron belt sponge (a three-dimensional porous network sponge material which is formed by taking the silicon carbide micron belt as a main structural unit). Wherein, the controllable formation and stable obtaining of the silicon carbide micron-sized band structure are realized by controlling the reaction temperature of the step (2) and the heat treatment time window of the step (3). Preferably, in step (1), the silicon source is a mixture of silicon powder and silicon dioxide powder, or is a silicon oxide powder. Preferably, in the step (1), the porous template is a carbon fiber felt, and the thickness of the porous template is 1-10 mm, and mos