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CN-121974394-A - Ceramic nanofiber, preparation method thereof and ceramic aerogel prepared by ceramic nanofiber

CN121974394ACN 121974394 ACN121974394 ACN 121974394ACN-121974394-A

Abstract

The application discloses a ceramic nanofiber and a preparation method thereof, and ceramic aerogel prepared by the same, wherein the method for preparing the ceramic nanofiber comprises the following steps of 1) mixing and uniformly dispersing an inorganic precursor, a chelating agent, a solvent and a stabilizer to obtain mixed sol; 2) generating active linear inorganic polymer sol by controlling hydrolysis and polycondensation reaction of inorganic precursors in the mixed sol, 3) balancing and concentrating the linear inorganic polymer sol to regulate the viscosity and the viscoelasticity of the sol to be in a proper interval, 4) carrying out electrostatic spinning on the sol regulated in the step 3) to obtain precursor fibers, and calcining the precursor fibers to obtain the ceramic nano fibers. The method can rapidly prepare the high-strength parallel-wire ceramic nanofiber and can simply and conveniently assemble the high-strength parallel-wire ceramic nanofiber into the high-elasticity ceramic aerogel material.

Inventors

  • ZHANG JUNHUA
  • XU LING
  • LIU PENG
  • YANG QILIANG
  • XIONG Qinbiao
  • JI QUN
  • WANG LIJUAN

Assignees

  • 奇瑞汽车股份有限公司

Dates

Publication Date
20260505
Application Date
20260126

Claims (10)

  1. 1. The preparation method of the ceramic nanofiber is characterized by comprising the following steps of: 1) Mixing and uniformly dispersing an inorganic precursor, a chelating agent, a solvent and a stabilizer to obtain mixed sol; 2) By controlling the hydrolysis and polycondensation reaction of inorganic precursors in the mixed sol, linear inorganic polymer sol with activity is generated; 3) Equilibrating and concentrating the linear inorganic polymer sol to regulate the viscosity and viscoelasticity of the sol to be in a proper range; 4) And 3) carrying out electrostatic spinning on the sol regulated and controlled in the step 3) to obtain precursor fibers, and calcining the precursor fibers to obtain the ceramic nanofibers.
  2. 2. The method of claim 1, wherein in step 1), the inorganic precursor is one or more selected from the group consisting of a zirconium source, a titanium source, and a silicon source, and/or, In the step 1), the chelating agent is selected from one or more of acetic acid, acetylacetone and citric acid, the mol ratio of the inorganic precursor to the chelating agent is controlled to be 1:0.5-1:1.5, and/or, In the step 1), the solvent is a composite solvent of an alcohol solvent and a polar solvent, the use amount of the composite solvent is 5-50 times of the sum gram weight of the inorganic precursor and the chelating agent, the mass ratio of the alcohol solvent to the polar solvent is 1:9-9:1, and/or, In the step 1), the stabilizer is isopropyl ether or boric acid, and the molar ratio of the stabilizer to the inorganic precursor is 0.1-1:1.
  3. 3. The method for preparing ceramic nanofibers according to claim 1 or 2, wherein in step 1), said mixing is performed in a stirring state for 4 to 8 hours at a temperature of 50 to 80 ℃.
  4. 4. The method for preparing ceramic nanofibers according to claim 1, wherein in the step 2), the conditions for controlling the hydrolysis and polycondensation of the inorganic precursor in the mixed sol comprise diluting deionized water with a solvent, slowly adding the diluted deionized water into the mixed sol in the step 1) for reaction, and controlling the reaction temperature to be 30-50 ℃ and the reaction time to be 4-8 hours.
  5. 5. The method for preparing ceramic nanofibers according to claim 1, wherein in step 3), the equilibrium concentration is controlled by pumping the reaction solvent product by a vacuum pump, so that the polymerization degree of the high-activity linear inorganic molecular chain is 20-100, the viscosity of the sol is 500-10000 cp, the storage modulus is 100-300 Pa, and the storage modulus/loss modulus=1.5-3.
  6. 6. The method for preparing ceramic nanofibers according to claim 1, wherein in the step 4), the condition of the calcination treatment comprises that the calcination atmosphere is air or oxygen, the temperature is raised to 300-1200 ℃ at a temperature raising rate of 1-10 ℃ per minute, and the retention time is 100-200 min.
  7. 7. The ceramic nanofiber prepared by the method of any one of claims 1-6, wherein the ceramic nanofiber has a parallel silk nanofiber structure, the diameter of the single parallel silk fiber is 100-500 nm, and the length-diameter ratio is more than or equal to 1000.
  8. 8. A method for preparing ceramic aerogel by using the ceramic nanofiber prepared by the method of any one of claims 1 to 6 or the ceramic nanofiber of claim 7, which is characterized by comprising the steps of pulping, freeze-drying and heat-treating the ceramic nanofiber to obtain elastic ceramic aerogel.
  9. 9. The method for preparing ceramic aerogel according to claim 8, wherein the beating treatment comprises placing ceramic nanofibers into deionized water, stirring, shearing and dispersing to obtain slurry, wherein the weight ratio of ceramic nanofiber fibers to deionized water is 0.5-5:100, and/or, The freeze drying comprises adding tetraethoxysilane and hydrochloric acid into slurry obtained by pulping treatment, wherein the adding proportion is 1:0.01:0.001 compared with the weight of the slurry, the freeze drying is usually 48-96 h, and/or, The heat treatment condition comprises that the calcination atmosphere is air or oxygen, the temperature is raised to 300-1200 ℃ at the temperature rising rate of 1-10 ℃ per minute, and the holding time is 100-200 minutes.
  10. 10. A ceramic aerogel prepared by the method of any one of claims 8-9, said ceramic aerogel being comprised of a globally co-mingled nanofiber structure, the entirety of which is in a continuous, uniform three-dimensional network topology.

Description

Ceramic nanofiber, preparation method thereof and ceramic aerogel prepared by ceramic nanofiber Technical Field The application relates to the technical field of ceramic fiber material preparation, in particular to ceramic nanofiber, a preparation method thereof and ceramic aerogel prepared by the same. Background The ceramic aerogel has the advantages of high temperature resistance, corrosion resistance, good chemical inertness, excellent heat insulation and the like, and is an indispensable key material in the fields of national defense and military industry, energy chemical industry, new energy automobiles and the like. However, the traditional ceramic aerogel has the defects of large brittleness and easy breakage, and is easy to cause irreversible structural damage in the actual use process, thereby seriously threatening the safety of personnel and equipment. The appearance of the ceramic nanofiber aerogel brings normal form transformation to the design of the ceramic aerogel, and the ceramic nanofiber with high length-diameter ratio can better disperse stress and enable the ceramic aerogel to show certain elasticity in a macroscopic sense compared with the traditional particle units of the ceramic aerogel. However, when facing extremely severe scenes, the conventional ceramic nanofiber aerogel still faces the defect of insufficient mechanical strength in the long-term use process, because the ceramic nanofiber prepared by the polymer template process has a large number of microscopic defects in the ceramization process. These microscopic defects tend to be stress concentration points that can amplify the brittleness problem of ceramic nanofiber aerogels in extremely harsh environments. Therefore, how to further realize the breakthrough of the mechanical properties of the ceramic aerogel material is a scientific difficulty to be solved. Researchers have studied the preparation of ceramic aerogels by adding very little polymer in order to minimize the negative effects of the polymer during ceramization, and the prepared ceramic aerogels have achieved a degree of elasticity. Further, researchers try to completely break away the polymer, and the polymer is synthesized into inorganic molecular chains with a certain degree of polymerization and directly prepared into ceramic nanofibers, and finally, the ceramic aerogel is prepared through a freeze-drying process, so that the mechanical properties are further improved. The methods focus on improving the mechanical strength of the building unit of the ceramic aerogel so as to obtain the breakthrough of mechanical properties to the greatest extent. However, the mechanical properties of the related ceramic aerogel are not always capable of meeting the requirements of increasingly developed high-precision equipment due to the limitation of the preparation process of the ceramic material and the inherent low dislocation slip system of the ceramic material. Disclosure of Invention In view of the above, the main object of the present application is to provide a ceramic nanofiber, a preparation method thereof and a ceramic aerogel prepared by the method, which can rapidly prepare a high-strength parallel-wire ceramic nanofiber and simply assemble the ceramic nanofiber into a high-elasticity ceramic aerogel material, so as to solve the problem of mechanical property deficiency of the ceramic aerogel caused by insufficient strength of a building element. In order to achieve the above object, the first aspect of the present application provides a method for preparing ceramic nanofibers, comprising the steps of: 1) Mixing and uniformly dispersing an inorganic precursor, a chelating agent, a solvent and a stabilizer to obtain mixed sol; 2) By controlling the hydrolysis and polycondensation reaction of inorganic precursors in the mixed sol, linear inorganic polymer sol with activity is generated; 3) Equilibrating and concentrating the linear inorganic polymer sol to regulate the viscosity and viscoelasticity of the sol to be in a proper range; 4) And 3) carrying out electrostatic spinning on the sol regulated and controlled in the step 3) to obtain precursor fibers, and calcining the precursor fibers to obtain the ceramic nanofiber membrane. Further, in the step 1), the inorganic precursor is one or more selected from a zirconium source, a titanium source and a silicon source. Further, in the step 1), the chelating agent is one or more selected from acetic acid, acetylacetone and citric acid, and the molar ratio of the inorganic precursor to the chelating agent is controlled to be 1:0.5-1:1.5. Further, in the step 1), the solvent is a composite solvent of an alcohol solvent and a polar solvent, the use amount of the composite solvent is 5-50 times of the sum gram weight of the inorganic precursor and the chelating agent, and the mass ratio of the alcohol solvent to the polar solvent is 1:9-9:1. In step 1), the stabilizer is isopropyl ether or boric acid, and the molar rati