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CN-121974700-A - High-toughness silicon carbide ceramic composite material and preparation method thereof

CN121974700ACN 121974700 ACN121974700 ACN 121974700ACN-121974700-A

Abstract

The application provides a high-toughness silicon carbide ceramic composite material and a preparation method thereof, which belong to the technical field of ceramic composite materials, wherein a eutectic liquid phase is formed in situ through yttrium-lanthanum dual rare earth boride, a necessary condition is created for subsequent reaction, in the environment, tiB X -C precursor and graphene quantum dot@silicon nitride composite powder are in synergistic reaction, a multi-scale reinforced structure which takes titanium carbide/beta-silicon nitride whisker and the like as a framework and boron carbide particles are dispersed therein can be formed in the material, a carbon layer converted by the graphene quantum dot forms a relatively weak interface around the whisker in the aspect of interface regulation, thereby being beneficial to exerting the effects of whisker extraction and the like, promoting the formation of a two-dimensional boron nitride sheet layer to introduce crack deflection effect, and when cracks are expanded, the energy of the composite material can be synergistically dissipated by the processes of particle pinning, crack deflection, whisker bridging, extraction and the like, so that the composite material has high toughness, and is suitable for the field of green refractory ceramics.

Inventors

  • LI HUAJIAN
  • ZHANG TIANFENG
  • FENG XIAOXIA
  • ZHANG XUEWEN
  • Ke meiya
  • LI JIAFENG

Assignees

  • 兰溪泛翌精细陶瓷有限公司

Dates

Publication Date
20260505
Application Date
20260306

Claims (10)

  1. 1. The preparation method of the high-toughness silicon carbide ceramic composite material is characterized by comprising the following steps of: S1, ball milling titanium dioxide nano powder, amorphous boron powder and carbon black powder, and performing heat treatment to obtain a TiB X -C nano composite precursor; s2, preparing graphene quantum dots by using citric acid and urea to react, and obtaining graphene quantum dot@silicon nitride composite powder by using a composite reaction of the graphene quantum dots and alpha-silicon nitride suspension; S3, gelatinizing yttrium nitrate, lanthanum nitrate, boric acid and citric acid, and then drying, heat treating and purifying to obtain yttrium-lanthanum double rare earth boride solid solution nano-powder; S4, mixing silicon carbide, tiB X -C nano composite precursor, graphene quantum dot@silicon nitride composite powder, yttrium-lanthanum dual rare earth boride solid solution nano powder and polyvinyl alcohol by a wet method to obtain composite slurry, drying and sieving to obtain composite granulating powder, and then performing plasma sintering to obtain the high-toughness silicon carbide ceramic composite material.
  2. 2. The method for preparing a high-toughness silicon carbide ceramic composite material according to claim 1, wherein in S1: the ball milling is to mix titanium dioxide nano powder, amorphous boron powder, carbon black powder and absolute ethyl alcohol, and then ball mill the mixture in a ball mill with high energy to obtain precursor mixed slurry; the heat treatment is to obtain a prefabricated precursor by vacuum drying the precursor mixed slurry, and heat treatment is carried out at a temperature rise under inert atmosphere; The mol ratio of the titanium dioxide nano powder to the amorphous boron powder to the carbon black powder is 1 (2.1-2.4) to 4.5-5.5.
  3. 3. The method for preparing a high-toughness silicon carbide ceramic composite material according to claim 1, wherein in S2: the mass ratio of the citric acid to the urea is 1 (1.8-2.2).
  4. 4. The method for preparing a high-toughness silicon carbide ceramic composite material according to claim 1, wherein in S2: the feeding amount of the citric acid is 5-15% of the mass of the alpha-silicon nitride; The graphene quantum dots are prepared by dispersing citric acid and urea in deionized water for hydrothermal reaction; The graphene quantum dot@silicon nitride composite powder is prepared by adding graphene quantum dots into alpha-silicon nitride suspension, adjusting pH and stirring for reaction.
  5. 5. The method for preparing a high-toughness silicon carbide ceramic composite material according to claim 1, wherein in S3: the gelation is to disperse yttrium nitrate, lanthanum nitrate, boric acid and citric acid in deionized water to obtain sol, and the sol is heated and pH is regulated by ammonia water to obtain gel; The heat treatment is heating treatment under nitrogen protection after the gel is dried; the molar ratio of yttrium nitrate to lanthanum nitrate is (0.9-1.1): 1.
  6. 6. The method for preparing a high-toughness silicon carbide ceramic composite material according to claim 1, wherein in S3: The molar ratio of the total molar quantity of the yttrium nitrate and the lanthanum nitrate to the boric acid is 1 (5.8-6.2).
  7. 7. The method for preparing a high-toughness silicon carbide ceramic composite material according to claim 1, wherein in S3: The molar ratio of the total molar quantity of the yttrium nitrate and the lanthanum nitrate to the citric acid is 1 (1.4-1.6).
  8. 8. The method for preparing a high-toughness silicon carbide ceramic composite material according to claim 1, wherein in S4: the plasma sintering is that the composite granulating powder is heated and sintered under vacuum, and uniaxial pressure is applied in the heating process; The mass ratio of the silicon carbide, the TiB X -C nano composite precursor, the graphene quantum dot@silicon nitride composite powder, the yttrium-lanthanum dual rare earth boride solid solution nano powder and the polyvinyl alcohol is (85-90): (4-6): (2-4): (1.5-2.5): (0.8-1.2).
  9. 9. The method for preparing a high-toughness silicon carbide ceramic composite material according to claim 1, wherein in S4: the vacuum degree of the composite granulated powder during sintering is 10 -1 -10 -3 Pa; the sintering temperature of the composite granulating powder is 1750-1900 ℃.
  10. 10. A high toughness silicon carbide ceramic composite material prepared by the method according to any one of claims 1 to 9.

Description

High-toughness silicon carbide ceramic composite material and preparation method thereof Technical Field The invention belongs to the technical field of ceramic composite materials, and relates to a high-toughness silicon carbide ceramic composite material and a preparation method thereof, which are suitable for the field of green special refractory ceramics. Background Silicon carbide ceramic is used as one of special refractory ceramic materials, and has wide application prospect in the tip fields of aerospace, high-end equipment manufacturing, nuclear industry and the like due to high hardness, excellent high-temperature strength, corrosion resistance and oxidation resistance. However, its inherent covalent bond structure results in its high intrinsic brittleness and low fracture toughness, which weakness limits to some extent its reliability and range of application as a structural component. Therefore, the development of the silicon carbide ceramic composite material with high toughness is a key point for widening engineering application. Currently, the main technical path for improving the toughness of silicon carbide ceramics mainly relies on direct recombination of externally added reinforcing phases, such as adding silicon carbide whiskers/fibers, carbon fibers or hard particles, and the like. However, the traditional technology generally faces three major bottlenecks, namely poor dispersion of a reinforcing phase, extremely easy agglomeration of a nano-or micron-sized reinforcing body in the powder mixing process, difficult realization of expected toughening effect and degradation of mechanical properties of materials due to the fact that the agglomeration bodies become original defects inside the materials after sintering, single toughening effect and limited efficiency, namely difficult breaking of the bottleneck due to the fact that the traditional composite material is always only dependent on crack deflection or bridging and the like due to the fact that the traditional composite material is insufficient in synergistic effect, and difficult interface regulation and control, namely critical to the toughening effect due to the fact that the interface bonding state between the reinforcing phase and a matrix is difficult to actively design and accurately regulate, and difficult full play of efficient toughening effects such as whisker extraction. Disclosure of Invention The application aims to provide a high-toughness silicon carbide ceramic composite material and a preparation method thereof. According to the application, the yttrium-lanthanum dual rare earth boride auxiliary agent can form a layer of low-melting-point liquid phase in situ in the sintering process, the liquid phase is not only helpful for promoting rapid densification of a matrix, but also can be used as a substance transmission medium to create a necessary condition for subsequent reaction, in the liquid phase environment, a TiB X -C precursor and graphene quantum dot@silicon nitride composite powder can be subjected to synergistic reaction to form a multi-scale reinforcing structure in the material, on the one hand, a relatively weak bonding interface is formed around titanium carbide whiskers on the basis of fine regulation of the interface, thereby being beneficial to the development of toughening effects such as whisker extraction, on the other hand, promoting the formation of lamellar phases such as two-dimensional boron nitride and the like to introduce crack deflection, and finally, when cracks are expanded, the energy of the nano-particle pinning, amorphous phase passivation, boron nitride sheet layer deflection, whisker bridging/extraction and the like processes can be further dissipated, so that higher toughness is realized. In order to achieve the purpose, the invention adopts the following technical scheme: in a first aspect, the present invention provides a method for preparing a high toughness silicon carbide ceramic composite, the method comprising: The preparation method comprises the following steps of S1, performing high-energy ball milling on titanium dioxide nano powder, amorphous boron powder and carbon black powder and absolute ethyl alcohol to obtain precursor mixed slurry, performing vacuum drying on the precursor mixed slurry to obtain a prefabricated precursor, heating and heat treatment under inert atmosphere, naturally cooling, grinding and sieving to obtain a TiB X -C nano composite precursor; S2, dispersing citric acid and urea in deionized water to obtain a reaction solution A, performing hydrothermal reaction, centrifuging and purifying to obtain graphene quantum dot dispersion liquid, adding alpha-silicon nitride into deionized water to prepare alpha-silicon nitride suspension, adding graphene quantum dot dispersion liquid into the alpha-silicon nitride suspension to obtain a reaction solution B, adjusting the pH value, magnetically stirring, and vacuum drying to obtain graphene quantum dot@sili