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CN-122010587-A - Preparation method of boron nitride fiber reinforced ceramic matrix composite

CN122010587ACN 122010587 ACN122010587 ACN 122010587ACN-122010587-A

Abstract

The invention provides a preparation method of a boron nitride fiber reinforced ceramic matrix composite material, belonging to the technical field of boron nitride fiber reinforced ceramic matrix composite materials; the preparation method comprises the steps of preparing mixed slurry, preprocessing fiber cloth, coating, solidifying and sintering, wherein the step of preparing the mixed slurry comprises the steps of preparing silicon boron oxygen nitrogen powder, coating and pulping, the step of preparing the silicon boron oxygen nitrogen powder comprises the steps of mixing tetraethoxysilane with absolute ethyl alcohol, dropwise adding trimethyl borate after uniformly stirring, keeping the dropwise adding speed at 1-2mL/min, keeping the stirring speed at 480-520r/min, adjusting the pH value to 3-4 after the dropwise adding is finished, adding hexamethyldisilazane, stirring for 2-3h at 40-50 ℃ to obtain sol, and standing, ageing, drying and roasting to obtain the silicon boron oxygen nitrogen powder.

Inventors

  • LIU YUN
  • SHAO CHANGTAO
  • LUAN QIANG
  • WANG TONGTONG
  • CUI HAOZHE
  • WEI QIHONG
  • WANG HONGSHENG
  • LIU RUIXIANG
  • LIU YUANYUAN

Assignees

  • 山东工业陶瓷研究设计院有限公司

Dates

Publication Date
20260512
Application Date
20260410

Claims (9)

  1. 1. The preparation method of the boron nitride fiber reinforced ceramic matrix composite material is characterized by comprising the steps of preparing mixed slurry, preprocessing fiber cloth, coating, solidifying and sintering; the preparation of the mixed slurry comprises the steps of preparing silicon boron oxygen nitrogen powder, coating and pulping; Mixing ethyl orthosilicate with absolute ethyl alcohol, uniformly stirring, then dropwise adding trimethyl borate with the dropwise adding speed of 1-2mL/min, keeping the stirring speed at 480-520r/min while dropwise adding, adjusting the pH value to 3-4 after dropwise adding, adding hexamethyldisilazane, stirring at 40-50 ℃ for 2-3h to obtain sol, standing, ageing, drying and roasting to obtain the silicon boron oxygen nitrogen powder; The coating step is that silicon boron oxygen nitrogen powder is put into absolute ethyl alcohol, after being stirred uniformly, alumina sol is added, the adding speed is controlled to be 1.5-2.0g/min, after the adding is finished, ultrasonic dispersion is carried out, the stirring is carried out for 2.5-3.0h at 46-52 ℃, and after the stirring is finished, the alumina coated silicon boron oxygen nitrogen powder is obtained after aging, drying and roasting.
  2. 2. The method for preparing a boron nitride fiber reinforced ceramic matrix composite according to claim 1, wherein, In the step of preparing the silicon boron oxygen nitrogen powder, the mass ratio of the tetraethoxysilane to the absolute ethyl alcohol to the trimethyl borate to the hexamethyldisilazane is 37-38:95-100:7.0-7.3:4.8-5.0.
  3. 3. The method for preparing a boron nitride fiber reinforced ceramic matrix composite according to claim 1, wherein, In the coating step, the mass ratio of the silicon boron oxygen nitrogen powder to the absolute ethyl alcohol to the alumina sol is 10-12:100:60-65.
  4. 4. The method for preparing a boron nitride fiber reinforced ceramic matrix composite according to claim 1, wherein, In the coating step, the preparation method of the alumina sol comprises the steps of adding aluminum isopropoxide into absolute ethyl alcohol, stirring for 25-30min at 280-320rpm, adding glacial acetic acid, continuing stirring for 25-30min at room temperature, raising the temperature to 42-47 ℃ after stirring, adding deionized water, controlling the adding time to 10-15min, and continuing stirring for 1.5-2.0h at 42-47 ℃ to obtain the alumina sol; The volume-mass ratio of the absolute ethyl alcohol to the aluminum isopropoxide to the glacial acetic acid to the deionized water is 50-55mL, 1.8-2.2g, 0.58-0.62g and 0.52-0.56g.
  5. 5. The method for preparing a boron nitride fiber reinforced ceramic matrix composite according to claim 1, wherein, The pulping step comprises the steps of adding deionized water into absolute ethyl alcohol, stirring uniformly, adding a kH560 silane coupling agent, heating to 40-45 ℃, keeping the temperature, stirring for 25-30min, adding polyvinylpyrrolidone, stirring for 20-25min at 250-280rpm, adding aluminum oxide coated silicon boron oxygen nitrogen powder and yttrium oxide for ball milling treatment, wherein the ball-milling time is 15-20min, the ball milling rotating speed is 200-230rpm, stirring for 1.5-2.0h at 40-45 ℃ after ball milling, adding 6-8g of glycerol, stirring for 30-35min, reducing the temperature to 30-32 ℃ and stirring for 1.0-1.2h at 250-270rpm to obtain mixed slurry.
  6. 6. The method for preparing a boron nitride fiber reinforced ceramic matrix composite according to claim 5, wherein, The mass ratio of the absolute ethyl alcohol to the deionized water to the kH560 silane coupling agent to the polyvinylpyrrolidone to the alumina coated silicon boron oxygen nitrogen powder to the yttrium oxide is 40:5-7:1.4-1.7:2.0-2.4:45-50:0.8-1.0.
  7. 7. The method for preparing a boron nitride fiber reinforced ceramic matrix composite according to claim 1, wherein, The pretreatment method comprises the steps of placing boron nitride fiber cloth in a plasma device for etching, introducing argon, controlling the argon flow to be 20-25sccm, controlling the vacuum degree to be-0.07 to-0.075 MPa, and obtaining pretreated fiber cloth, wherein the etching power is 120-130W, and the etching time is 7-10 min; The boron nitride fiber cloth has the weaving density of 20-23 pieces per 10mm in the warp direction and 20-23 pieces per 10mm in the weft direction, the surface density of 120-130g/m 2 and the thickness of 280-300 mu m.
  8. 8. The method for preparing a boron nitride fiber reinforced ceramic matrix composite according to claim 1, wherein, Spreading the pretreated fiber cloth on a vacuum adsorption workbench, regulating the vacuum degree to be minus 0.08 to minus 0.09MPa, adding mixed slurry, carrying out doctor blade coating, controlling the doctor blade coating speed to be 20-25mm/s, standing for 15-20min after the doctor blade coating is finished, controlling the coating thickness to be 24-28 mu m, drying, putting into a die of a hot press forming machine, introducing nitrogen, keeping the nitrogen flow to be 200-210mL/min, controlling the pressure to be 0.50-0.52MPa, standing for 5-7min at room temperature, raising the temperature to 80-82 ℃, preserving the heat for 28-32min at 1.0-1.2MPa, raising the temperature to 118-123 ℃, preserving the heat for 28-32min at 1.4-1.7MPa, continuing raising the temperature to 180-183 ℃, preserving the heat for 1.5-2.0h at 1.4-1.7MPa, and reducing the temperature to the room temperature to obtain the composite boron nitride fiber cloth.
  9. 9. The method for preparing a boron nitride fiber reinforced ceramic matrix composite according to claim 1, wherein, The sintering step is that the composite boron nitride fiber is put into a sintering furnace, nitrogen is introduced, the temperature is increased to 580-600 ℃ at the speed of 4.0-5.0 ℃ per minute, the temperature is kept for 25-30 minutes, the switching atmosphere is argon, the temperature is increased to 1300-1330 ℃ at the speed of 2.5-3.0 ℃ per minute, the pressure is increased to 2.5-3.0MPa, the temperature is kept for 3.0-3.3 hours, the temperature is reduced to 580-600 ℃ at the speed of 4.0-5.0 ℃ per minute after the heat preservation is finished, the argon is closed, and the boron nitride fiber reinforced ceramic matrix composite is obtained after natural cooling to room temperature.

Description

Preparation method of boron nitride fiber reinforced ceramic matrix composite Technical Field The invention belongs to the technical field of boron nitride fiber reinforced ceramic matrix composite materials, and particularly relates to a preparation method of a boron nitride fiber reinforced ceramic matrix composite material. Background The ceramic matrix composite is widely applied to the fields of aerospace, energy chemical industry and the like due to the excellent high-temperature stability, wear resistance and oxidation resistance, however, the traditional ceramic matrix composite has the defects of large brittleness, poor toughness, insufficient thermal shock resistance and the like, and the application of the ceramic matrix composite in high-temperature bearing structural components is limited. However, conventional ceramic matrix composites (e.g., alumina-based, silicon carbide-based, etc.) suffer from the following significant drawbacks: firstly, the brittleness is high, the fracture toughness is low, sudden fracture is easy to occur under the action of external force impact or complex stress, and the application of the alloy in a dynamic service scene is severely limited; Secondly, grain boundary oxidation and phase structure transformation are easy to occur under a high-temperature environment (more than 1200 ℃), so that mechanical properties are suddenly attenuated, and the requirements of hypersonic aircraft wave-transparent components, aeroengine hot-end components and the like on long-term stable service of materials under an extreme environment of more than 1600 ℃ cannot be met. In order to solve the problems, the prior art introduces Boron Nitride (BN) fiber as a reinforcing material to prepare a boron nitride fiber reinforced ceramic matrix composite material, wherein the boron nitride fiber is used as a high-performance wave-transmitting ceramic in afternoon, has high temperature resistance and stable dielectric property at high temperature, and meanwhile, the boron nitride fiber has excellent chemical stability and strong thermal shock resistance and corrosion resistance, and can effectively resist the severe service environment of a hypersonic aircraft; Therefore, the boron nitride fiber reinforced ceramic matrix composite is a new generation of wave-transmitting material which can meet the long-term stable service of the wave-transmitting component for hypersonic aircraft in the ultra-high temperature environment above 1600 ℃ after being subjected to the heat resistance of 1200 ℃ quartz fiber composite and 1400 ℃ silicon nitride/silicon boron nitride fiber composite. However, the preparation technology of the existing boron nitride fiber reinforced ceramic matrix composite still has the following key bottlenecks: On one hand, the bonding strength of the interface between the fiber and the matrix is not matched, the surface of the boron nitride fiber is strong in chemical inertia, the wettability with the ceramic matrix is poor, and an ideal bonding interface is difficult to form; On the other hand, the densification degree of the matrix is insufficient, and defects such as pores, cracks and the like are easy to form in the preparation process, and can become stress concentration sources and oxidation channels in a high-temperature environment, so that the high-temperature resistance and long-term service stability of the material are reduced; in addition, the existing technology has poor suitability for fiber forms, and can not realize uniform compounding of fibers in different forms and a matrix, thereby further restricting the consistency of product performance and the large-scale application. Disclosure of Invention In order to solve the technical problems in the prior art, the invention provides a preparation method of a boron nitride fiber reinforced ceramic matrix composite material, which improves mechanical properties such as bending strength, fracture toughness and the like of a product and enhances high temperature resistance and long-term service stability. Aiming at the technical problems, the invention adopts the following technical scheme: The preparation method of the boron nitride fiber reinforced ceramic matrix composite material comprises the steps of preparing mixed slurry, preprocessing fiber cloth, coating and solidifying and sintering, and specifically comprises the following steps: 1. Preparation of mixed slurry (1) Preparation of silicon boron oxygen nitrogen powder Mixing tetraethoxysilane with absolute ethyl alcohol, stirring at 240-260rpm for 10-15min, dropwise adding trimethyl borate at a dropwise adding speed of 1-2mL/min, keeping a stirring speed of 480-520r/min while dropwise adding, stirring for 30-35min after dropwise adding, adding 0.10-0.13mol/L hydrochloric acid solution to adjust the pH value to 3-4, adding hexamethyldisilazane, heating to 40-50 ℃, and stirring for 2-3h under heat preservation to obtain sol; The mass ratio of the tetraethoxysilane