Gel-casting method for preparing high-performance silicon nitride ceramics

Abstract

The application relates to the field of advanced structural ceramics, and particularly discloses a gel injection molding method for preparing high-performance silicon nitride ceramics and a preparation method thereof. Raw materials include beta-SiN submicron powder 75 parts, YO submicron powder 8 parts, TiC submicron powder 5 parts, AlO superfine powder 5 parts, ZrO submicron powder 2 parts and wollastonite 5 parts in terms of mass ratio, a complex whisker regulator and an entry liquid are used, and ceramics are prepared through gel injection molding, dehydration, degreasing and gas pressure sintering. The grain morphology and interface combination are optimized through the whisker regulator, the slurry dispersion and the green body uniformity are improved through the entry liquid, and the product has a density greater than or equal to 99%, a Vickers hardness greater than or equal to 1700HV and a bending strength greater than or equal to 930MPa through 1700-1850 DEG C. gas pressure sintering, and the product has high density, high hardness, high toughness, wear resistance, corrosion resistance and long service life.

Description

Technical Field

[0001] This invention relates to the field of silicon nitride ceramics technology, specifically to a method for preparing high-performance silicon nitride ceramics by gel casting. Background Technology

[0002] Silicon nitride ceramics possess comprehensive advantages such as high strength, high hardness, excellent wear resistance, high temperature resistance, corrosion resistance, low coefficient of thermal expansion, and low density, making them a core material for key structural components in aerospace, high-end machinery, rail transportation, and new energy fields. Traditional silicon nitride preparation methods often employ hot pressing and atmospheric pressure sintering, which suffer from problems such as poor uniformity of the green body, low density, coarse grains, insufficient toughness, and difficulty in forming complex shapes. Gel casting can achieve near-net-shape forming, high green body strength, and uniform composition, but it still faces drawbacks such as poor powder dispersion, easy agglomeration, weak interfacial bonding, insufficient sintering densification, and difficulty in achieving a balance of mechanical properties.

[0003] Existing technologies mostly employ simple sintering aid systems, lacking systematic optimization of whisker reinforcement, interface control, and slurry stability, making it difficult to achieve high-performance and stable preparation with densities ≥99%, strength ≥930MPa, and hardness ≥1700HV. Therefore, developing a silicon nitride ceramic preparation technology with excellent formability, uniform dispersion, sufficient densification, and outstanding mechanical properties has significant engineering value. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing high-performance silicon nitride ceramics by gel casting, thereby resolving the problems mentioned in the background section.

[0005] The present invention solves the technical problem by adopting the following technical solution:

[0006] This invention provides a method for preparing high-performance silicon nitride ceramics by gel casting, wherein the raw materials include, by mass ratio: β-Si N 70-80 parts of submicron powder, Y O 7-9 parts submicron powder, 4-6 parts TiC submicron powder, Al O 4-6 parts of ultrafine powder, ZrO 1-3 parts submicron powder, 4-6 parts wollastonite, 5-8 parts whisker modifier, and 3-5 parts liquid.

[0007] Preferably, the raw materials include, by mass ratio: β-Si N 75 parts of submicron powder, Y O 8 parts of submicron powder, 5 parts of TiC submicron powder, and Al O 5 parts of ultrafine powder, ZrO Two parts of submicron powder, five parts of wollastonite, six and a half parts of whisker modifier, and four parts of liquid.

[0008] Preferably, the whisker regulator is prepared by the following steps:

[0009] S11: The aluminum borate whiskers are fed into a sufficient amount of potassium permanganate solution with a mass fraction of 8-10% and stirred thoroughly. Then, they are washed with water, filtered, and dried. The dried whiskers are ball-milled with the ball milling liquid at a weight ratio of (11-15):5. The ball milling speed is 1000-1500 r / min and the ball milling time is 2h to obtain the ball-milled whisker liquid.

[0010] The preparation method of the ball milling fluid is as follows: S11a: Stir silane coupling agent KH560 and ethanol aqueous solution with a mass fraction of 75-85% at a weight ratio of 3:(5-8) until fully mixed to obtain silane fluid;

[0011] S11b: 3-5 parts of carbon fiber are immersed in 5-8 parts of silane solution and stirred thoroughly to obtain carbon fiber solution; S11c: 4-7 parts of carbon fiber solution, 2-3 parts of graphene and 2-3 parts of magnesium oxide are mixed and stirred thoroughly to obtain ball milling slurry;

[0012] S12: Stir 3-5 parts of lanthanum oxide, 2-4 parts of titanium nitride, 5-8 parts of chitosan solution with a mass fraction of 5-7% and 2-3 parts of silicon dioxide thoroughly, then filter and dry to obtain lanthanum oxide additive;

[0013] S13: Continue ball milling the whisker solution and lanthanum oxide additive at a weight ratio of (8-11):5 until fully milled. After ball milling, sinter at 450-550℃ for 2 hours to obtain the whisker regulator.

[0014] Preferably, the aluminum borate whiskers have a diameter of 0.5-2 μm and an aspect ratio of 10-30; the graphene is single-layer or double-layer graphene with a particle size of 50-100 nm; and the carbon fibers have a diameter of 0.1-0.5 μm and a length of 5-20 μm.

[0015] Preferably, the immersion liquid is prepared by stirring thoroughly a sodium dodecylbenzenesulfonate solution (8-12% by mass), sodium alginate powder, and β-cyclodextrin in a weight ratio of (7-11):(3-4):2.

[0016] Preferably, the β-Si N Submicron powder particles have a diameter of 0.3-0.8 μm, Y O TiC, ZrO The submicron powder particles all have a diameter of 0.2-1.0 μm, Al O The ultrafine powder has a particle size of 50-200 nm, and the wollastonite has a particle size of 0.5-1.5 μm.

[0017] This invention also provides a method for preparing high-performance silicon nitride ceramics, comprising the following steps:

[0018] S1. β-Si N Submicron powder, Y O Submicron powder, TiC submicron powder, Al O Ultrafine powder, ZrO Submicron powder and wollastonite powder are mixed evenly according to a certain mass ratio to obtain a mixed powder;

[0019] S2. The mixed powder is mixed with organic matter, whisker regulator, and liquid to obtain a mixed slurry. The mixed slurry is then subjected to vacuum treatment to obtain β-Si. N gel-like liquid slurry;

[0020] S3. β-Si N After drying the gel liquid slurry, a green body is obtained. Then, it is subjected to gradient dehydration treatment at 60-160℃, and then heated to 500℃~550℃ for heat preservation and degreasing. S4. The degreased green body is placed in a nitrogen atmosphere for gas pressure sintering at a sintering temperature of 1700~1850℃. After heat preservation, it is cooled with the furnace to obtain high-performance silicon nitride ceramics.

[0021] Preferably, the organic matter in step S2 includes an organic monomer, a crosslinking agent, and an initiator. The organic monomer is acrylamide, the crosslinking agent is methylenebisacrylamide, and the solid content of the mixed slurry is 50-65 vol%. The vacuum degassing time is 15-30 min.

[0022] Preferably, the gradient dehydration in step S3 is as follows: holding at 60-80℃ for 1-2 hours, holding at 100-120℃ for 1-2 hours, and holding at 140-160℃ for 0.5-1 hours; the degreasing heating rate is 1-3℃ / min, and the degreasing holding time is 2-4 hours.

[0023] Preferably, in step S4, the nitrogen pressure for gas pressure sintering is 1-10 MPa, the heating rate is 5-10 °C / min, the sintering holding time is 2-4 h, and the furnace is cooled to below 200 °C before being removed from the furnace.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention significantly improves the quality of gel injection molding by combining an organic liquid with an organic system, thereby significantly improving powder dispersibility and completely solving the β-Si problem. N The agglomeration problem is addressed with high uniformity of the billet, eliminating delamination and defects, resulting in high near-net-shape forming accuracy and significantly reducing subsequent processing costs. Whisker regulators achieve synergistic strengthening and toughening. A multi-scale reinforcement system composed of aluminum borate whiskers, carbon fibers, and graphene, combined with lanthanum oxide, titanium nitride, chitosan, and silicon dioxide, achieves interface modification and grain boundary optimization. Through multiple mechanisms such as crack deflection, whisker pull-out, and fiber bridging, strength, hardness, and toughness are simultaneously improved. Highly efficient and thorough densification is achieved through nitrogen pressure sintering at 1700-1850℃, inhibiting silicon nitride decomposition, promoting liquid-phase sintering and uniform grain growth, resulting in a density ≥99%, fine grains, a dense microstructure, and no obvious porosity or defects. This achieves a Vickers hardness ≥1700 HV, flexural strength ≥930 MPa, and fracture toughness ≥7.5 MPa·m. 1 / 2 It possesses high hardness, high strength, high toughness, and high wear resistance, far exceeding conventional silicon nitride ceramics. Its corrosion resistance and service life are significantly extended. High density and stable grain boundary phases greatly improve resistance to acid, alkali, oil, and water vapor corrosion, with a corrosion weight loss rate ≤0.15%. Under harsh working conditions, its service life is increased by 3-5 times. The process is highly controllable and repeatable, suitable for mass production, and can be used to manufacture complex-shaped structural parts. It is widely used in high-end fields such as aerospace high-temperature components, high-speed bearings, mechanical seals, cutting tools, and new energy equipment. The raw material formulation is scientific and cost-effective. It uses common powders and additives in a reasonable ratio, eliminating the need for expensive raw materials, and achieving good economic efficiency while ensuring high performance, which is conducive to industrialization. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This embodiment describes a gel casting method for preparing high-performance silicon nitride ceramics. The raw materials, by mass ratio, include: β-Si N 70-80 parts of submicron powder, Y O 7-9 parts submicron powder, 4-6 parts TiC submicron powder, Al O 4-6 parts of ultrafine powder, ZrO 1-3 parts submicron powder, 4-6 parts wollastonite, 5-8 parts whisker modifier, and 3-5 parts liquid.

[0028] The raw materials in this embodiment include, by mass ratio: β-Si N 75 parts of submicron powder, Y O 8 parts of submicron powder, 5 parts of TiC submicron powder, and Al O 5 parts of ultrafine powder, ZrO Two parts of submicron powder, five parts of wollastonite, six and a half parts of whisker modifier, and four parts of liquid.

[0029] The whisker regulator in this embodiment is prepared through the following steps:

[0030] S11: The aluminum borate whiskers are fed into a sufficient amount of potassium permanganate solution with a mass fraction of 8-10% and stirred thoroughly. Then, they are washed with water, filtered, and dried. The dried whiskers are ball-milled with the ball milling liquid at a weight ratio of (11-15):5. The ball milling speed is 1000-1500 r / min and the ball milling time is 2h to obtain the ball-milled whisker liquid.

[0031] The preparation method of the ball milling fluid is as follows: S11a: Stir silane coupling agent KH560 and ethanol aqueous solution with a mass fraction of 75-85% at a weight ratio of 3:(5-8) until fully mixed to obtain silane fluid;

[0032] S11b: 3-5 parts of carbon fiber are immersed in 5-8 parts of silane solution and stirred thoroughly to obtain carbon fiber solution; S11c: 4-7 parts of carbon fiber solution, 2-3 parts of graphene and 2-3 parts of magnesium oxide are mixed and stirred thoroughly to obtain ball milling slurry;

[0033] S12: Stir 3-5 parts of lanthanum oxide, 2-4 parts of titanium nitride, 5-8 parts of chitosan solution with a mass fraction of 5-7% and 2-3 parts of silicon dioxide thoroughly, then filter and dry to obtain lanthanum oxide additive;

[0034] S13: Continue ball milling the whisker solution and lanthanum oxide additive at a weight ratio of (8-11):5 until fully milled. After ball milling, sinter at 450-550℃ for 2 hours to obtain the whisker regulator.

[0035] In this embodiment, the aluminum borate whiskers have a diameter of 0.5-2 μm and an aspect ratio of 10-30; the graphene is single-layer or double-layer graphene with a particle size of 50-100 nm; and the carbon fibers have a diameter of 0.1-0.5 μm and a length of 5-20 μm.

[0036] The immersion solution in this embodiment is prepared by mixing sodium dodecylbenzenesulfonate solution (8-12% by mass), sodium alginate powder, and β-cyclodextrin in a weight ratio of (7-11):(3-4):2.

[0037] β-Si in this embodiment N Submicron powder particles have a diameter of 0.3-0.8 μm, Y O TiC, ZrO The submicron powder particles all have a diameter of 0.2-1.0 μm, Al O The ultrafine powder has a particle size of 50-200 nm, and the wollastonite has a particle size of 0.5-1.5 μm.

[0038] This embodiment describes a method for preparing high-performance silicon nitride ceramics, comprising the following steps:

[0039] S1. β-Si N Submicron powder, Y O Submicron powder, TiC submicron powder, Al O Ultrafine powder, ZrO Submicron powder and wollastonite powder are mixed evenly according to a certain mass ratio to obtain a mixed powder;

[0040] S2. The mixed powder is mixed with organic matter, whisker regulator, and liquid to obtain a mixed slurry. The mixed slurry is then subjected to vacuum treatment to obtain β-Si. N gel-like liquid slurry;

[0041] S3. β-Si N After drying the gel liquid slurry, a green body is obtained. Then, it is subjected to gradient dehydration treatment at 60-160℃, and then heated to 500℃~550℃ for heat preservation and degreasing. S4. The degreased green body is placed in a nitrogen atmosphere for gas pressure sintering at a sintering temperature of 1700~1850℃. After heat preservation, it is cooled with the furnace to obtain high-performance silicon nitride ceramics.

[0042] In step S2 of this embodiment, the organic matter includes an organic monomer, a crosslinking agent, and an initiator. The organic monomer is acrylamide, the crosslinking agent is methylenebisacrylamide, the solid content of the mixed slurry is 50-65 vol%, and the vacuum defoaming time is 15-30 min.

[0043] In step S3 of this embodiment, the gradient dehydration is specifically as follows: holding at 60-80℃ for 1-2 hours, holding at 100-120℃ for 1-2 hours, and holding at 140-160℃ for 0.5-1 hours; the degreasing heating rate is 1-3℃ / min, and the degreasing holding time is 2-4 hours.

[0044] In step S4 of this embodiment, the nitrogen pressure for gas pressure sintering is 1-10 MPa, the heating rate is 5-10℃ / min, the sintering holding time is 2-4 h, and the furnace is cooled to below 200℃ before being removed from the furnace.

[0045] β-Si N 70-80 parts of submicron powder, Y O 7-9 parts submicron powder, 4-6 parts TiC submicron powder, Al O 4-6 parts of ultrafine powder, ZrO Submicron powder

[0046] Example 1

[0047] (1) Raw material ratio: β-Si N 75 copies, Y O 8 parts, TiC 5 parts, Al O 5 portions, ZrO 2 parts, 5 parts wollastonite. (2) Preparation of whisker regulator: S11: Aluminum borate whiskers are activated and dried by potassium permanganate; whiskers: ball milling liquid = 13:5, ball milling at 1200r / min for 2h; ball milling liquid: KH560: 80% ethanol = 3:6; 4 parts carbon fiber + 6 parts silane liquid → carbon fiber liquid; 5 parts carbon fiber liquid + 2.5 parts graphene + 2.5 parts magnesium oxide → ball milling liquid; S12: 4 parts lanthanum oxide + 3 parts titanium nitride + 6 parts 6% chitosan solution + 2.5 parts silicon dioxide → lanthanum oxide additive; S13: ball milling whisker liquid: lanthanum oxide additive = 9:5, sintering at 500℃ for 2h → whisker regulator. (3) Introducing liquid: 10% sodium dodecylbenzenesulfonate solution: sodium alginate: β-cyclodextrin = 9:3.5:2. (4) Preparation: Mix the powder for 4 hours; prepare a slurry with a solid content of 58 vol% and vacuum degassing for 20 minutes; dehydrate at a gradient of 60-160℃; degrease at 520℃ for 3 hours; sinter at 1800℃ for 3 hours with 5 MPa nitrogen and cool.

[0048] Example 2

[0049] (1) Raw material ratio: completely consistent with Example 1. (2) Preparation of whisker regulator: S11: Aluminum borate whiskers with a diameter of 0.5 μm and an aspect ratio of 10 were activated by soaking and stirring in potassium permanganate solution for 30 min, thoroughly washed with water until neutral, and dried at 100℃ for 2 h; Whiskers: ball milling liquid weight ratio 11:5, ball milling speed 1000 r / min, ball milling for 2 h; Ball milling liquid: KH560: 75% ethanol aqueous solution = 3:5; 3 parts carbon fiber were immersed in 5 parts silane liquid and stirred for 40 min to obtain carbon fiber liquid; 4 parts carbon fiber liquid + 2 parts graphene + 2 parts magnesium oxide were stirred at high speed for 30 min to obtain ball milling liquid; S12: 3 parts lanthanum oxide, 2 parts titanium nitride, 5 parts 5% chitosan solution, 2 parts silicon dioxide were stirred for 60 min, filtered and dried at 110℃ for 3 h to obtain lanthanum oxide additive; S13: ball milling whisker liquid: lanthanum oxide additive = 8:5, ball milling continued for 1 h, sintered at 450℃ for 2 h to obtain whisker regulator. (3) Injection solution: 8% sodium dodecylbenzenesulfonate solution: sodium alginate powder: β-cyclodextrin = 7:3:2, stir for 40 min until completely dissolved. (4) Preparation process: S1. The powder is ball-milled for 4 h with anhydrous ethanol as the medium, dried and passed through a 100-mesh sieve; S2. Acrylamide, methylenebisacrylamide, whisker regulator and injection solution are added to prepare a slurry with a solid content of 55 vol%, and vacuum defoaming for 30 min; S3. Injected into a mold and dried at 80℃ to form; Gradient dehydration: 60℃×2h→100℃×2h→140℃×1h; Degreasing at 500℃ for 4 h; S4. Nitrogen pressure 4MPa, sintering at 1700℃ for 4 h, heating rate 5℃ / min, and cooled to 150℃ with the furnace before being taken out of the furnace.

[0050] Example 3

[0051] (1) Raw material ratio: completely consistent with Example 1. (2) Preparation of whisker regulator: S11: Aluminum borate whiskers with a diameter of 2μm and an aspect ratio of 30 were activated with potassium permanganate solution for 40min, washed and dried with water; Whiskers: ball milling liquid weight ratio 15:5, ball milling speed 1500r / min, ball milling for 2h; Ball milling liquid: KH560: 85% ethanol aqueous solution = 3:8; 5 parts of carbon fiber were immersed in 8 parts of silane liquid and stirred for 60min; 7 parts of carbon fiber liquid + 3 parts of graphene + 3 parts of magnesium oxide were stirred for 60min to obtain ball milling liquid; S12: 5 parts of lanthanum oxide, 4 parts of titanium nitride, 8 parts of 7% chitosan solution, 3 parts of silicon dioxide were stirred for 80min, filtered and dried to obtain lanthanum oxide additive; S13: ball milling whisker liquid: lanthanum oxide additive = 11:5, ball milling for 1.5h, sintering at 550℃ for 2h to obtain whisker regulator. (3) Injection liquid: 12% sodium dodecylbenzenesulfonate solution: sodium alginate powder: β-cyclodextrin = 11:4:2, stir for 60min. (4) Preparation process: S1. Powder ball milling for 3h, drying and passing through a 120-mesh sieve; S2. Prepare slurry with a solid content of 65vol%, add organic monomers and dispersants, disperse at high speed for 60min, and vacuum degas for 15min; S3. After drying and molding, dehydrate in a gradient: 80℃×1h→120℃×1h→160℃×0.5h; degrease at 550℃ for 2h; S4. Nitrogen pressure 8MPa, sinter at 1850℃ for 2h, heating rate 10℃ / min, and cool with the furnace to below 200℃ before unloading.

[0052] Scale settings

[0053] Based on Example 1, all other conditions remain the same:

[0054] Comparative Example 1: No whisker modifier added;

[0055] Comparative Example 2: No added sexual fluid;

[0056] Comparative Example 3: Whisker regulator without lanthanum oxide additive;

[0057] Comparative Example 4: Whisker regulator was not used in the preparation of the ball milling slurry;

[0058] Comparative Example 5: No air pressure, conventional atmospheric pressure sintering at 1750℃.

[0059] The performance test results are as follows:

[0060] Group Density (%) Vickers hardness (HV) Bending strength (MPa) <![CDATA[Fracture toughness (MPa·m 1 / 2 )]]> Acid corrosion resistance weight loss (%) Example 1 99.3 1740 956 7.8 0.12 Example 2 99.0 1710 932 7.5 0.14 Example 3 99.5 1780 982 8.1 0.10 Comparative Example 1 95.6 1480 765 5.9 0.35 Comparative Example 2 96.2 1520 798 6.2 0.31 Comparative Example 3 96.8 1590 842 6.7 0.24 Comparative Example 4 97.1 1610 856 6.8 0.22 Comparative Example 5 94.2 1390 710 5.2 0.42

[0061] The performance test results above show that:

[0062] Density analysis showed that the densities of all embodiments of the present invention were ≥99.0%, with the highest reaching 99.5%. Comparative Example 1, without whisker modifier, had a density of 95.6%, indicating that the whisker modifier can fill intergranular voids and promote dense sintering. Comparative Example 2, without added liquid, had a density of 96.2%, indicating that the addition of liquid improved powder dispersion and reduced agglomeration porosity. Comparative Example 5, without pressure sintering, had a density of only 94.2%, proving that pressure can suppress Si... N High-temperature decomposition significantly improves densification.

[0063] Hardness and strength analysis of the examples showed a hardness ≥1700 HV and a strength ≥930 MPa, significantly higher than the comparative examples. Comparative Example 1 had a strength of only 765 MPa, indicating that the whisker modifier achieved toughening through pull-out, bridging, and crack deflection. Comparative Example 2 had a strength of 798 MPa, indicating that the inclusion of the slurry improved the uniformity of the slurry and ensured consistent composition of the green body. Comparative Examples 3 and 4 lacked lanthanum oxide additives or ball milling slurry, resulting in a significant decrease in performance, proving that the synergistic effect of the whisker modifier components was indispensable.

[0064] Fracture toughness analysis example: toughness ≥ 7.5 MPa·m 1 / 2 Maximum 8.1 MPa·m 1 / 2 The comparative toughness is generally lower than 7.0 MPa·m. 1 / 2 This indicates that the aluminum borate whiskers, carbon fibers, and graphene in the whisker modifier work synergistically to toughen the material and significantly improve its resistance to damage.

[0065] The corrosion weight loss rate of the example samples was ≤0.14%, while that of the comparative samples was >0.2%. The high density and stable grain boundary phase significantly reduced the penetration of corrosive media, and the whisker regulator and the liquid optimized the interface, thus improving the acid and alkali corrosion resistance.

[0066] The process parameters affect the performance of Example 3, which uses 1850℃ and 8MPa high pressure for short time sintering, resulting in the best density, hardness and strength. Example 2 uses a lower temperature and pressure, and the performance is slightly lower, but still meets the high performance requirements, which shows that the process window of the present invention is wide and highly controllable.

[0067] This invention significantly improves the quality of gel injection molding by combining an organic liquid with an organic system, thereby significantly improving powder dispersibility and completely solving the β-Si problem. N The problem of agglomeration is solved, the green body has high uniformity, no delamination, no defects, and high near-net-shape forming accuracy, which greatly reduces the subsequent processing costs.

[0068] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0069] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing high-performance silicon nitride ceramics using gel casting, characterized in that, The raw materials, by mass ratio, include: β-Si N 70-80 parts of submicron powder, Y O 7-9 parts submicron powder, 4-6 parts TiC submicron powder, Al O 4-6 parts of ultrafine powder, ZrO 1-3 parts submicron powder, 4-6 parts wollastonite, 5-8 parts whisker modifier, and 3-5 parts liquid.

2. The high-performance silicon nitride ceramic according to claim 1, characterized in that, The raw materials, by mass ratio, include: β-Si N 75 parts of submicron powder, Y O 8 parts of submicron powder, 5 parts of TiC submicron powder, and Al O 5 parts of ultrafine powder, ZrO Two parts of submicron powder, five parts of wollastonite, six and a half parts of whisker modifier, and four parts of liquid.

3. The high-performance silicon nitride ceramic according to claim 1, characterized in that, The whisker regulator is prepared by the following steps: S11: The aluminum borate whiskers are fed into a sufficient amount of potassium permanganate solution with a mass fraction of 8-10% and stirred thoroughly. Then, they are washed with water, filtered, and dried. The dried whiskers are ball-milled with the ball milling liquid at a weight ratio of (11-15):

5. The ball milling speed is 1000-1500 r / min and the ball milling time is 2h to obtain the ball-milled whisker liquid. The preparation method of the ball milling fluid is as follows: S11a: Stir silane coupling agent KH560 and ethanol aqueous solution with a mass fraction of 75-85% at a weight ratio of 3:(5-8) until fully mixed to obtain silane fluid; S11b: 3-5 parts of carbon fiber are immersed in 5-8 parts of silane solution and stirred thoroughly to obtain carbon fiber solution; S11c: 4-7 parts of carbon fiber solution, 2-3 parts of graphene and 2-3 parts of magnesium oxide are mixed and stirred thoroughly to obtain ball milling slurry; S12: Stir 3-5 parts of lanthanum oxide, 2-4 parts of titanium nitride, 5-8 parts of chitosan solution with a mass fraction of 5-7% and 2-3 parts of silicon dioxide thoroughly, then filter and dry to obtain lanthanum oxide additive; S13: Continue ball milling the whisker solution and lanthanum oxide additive at a weight ratio of (8-11):5 until fully milled. After ball milling, sinter at 450-550℃ for 2 hours to obtain the whisker regulator.

4. The high-performance silicon nitride ceramic according to claim 3, characterized in that, The aluminum borate whiskers have a diameter of 0.5-2 μm and an aspect ratio of 10-30; the graphene is single-layer or double-layer graphene with a particle size of 50-100 nm; the carbon fibers have a diameter of 0.1-0.5 μm and a length of 5-20 μm.

5. The high-performance silicon nitride ceramic according to claim 1, characterized in that, The immersion solution is prepared by mixing sodium dodecylbenzenesulfonate solution (8-12% by mass), sodium alginate powder, and β-cyclodextrin in a weight ratio of (7-11):(3-4):

2.

6. The high-performance silicon nitride ceramic according to claim 1, characterized in that, The β-Si N Submicron powder particles have a diameter of 0.3-0.8 μm, Y O TiC, ZrO The submicron powder particles all have a diameter of 0.2-1.0 μm, Al O The ultrafine powder has a particle size of 50-200 nm, and the wollastonite has a particle size of 0.5-1.5 μm.

7. A method for preparing high-performance silicon nitride ceramics as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. β-Si N Submicron powder, Y O Submicron powder, TiC submicron powder, Al O Ultrafine powder, ZrO Submicron powder and wollastonite powder are mixed evenly according to a certain mass ratio to obtain a mixed powder; S2. The mixed powder is mixed with organic matter, whisker regulator, and liquid to obtain a mixed slurry. The mixed slurry is then subjected to vacuum treatment to obtain β-Si. N gel-like liquid slurry; S3. β-Si N After drying the gel liquid slurry, a green body is obtained. Then, it undergoes gradient dehydration at 60-160℃, followed by heat preservation and degreasing at 500℃~550℃. S4. The degreased green body is placed in a nitrogen atmosphere for gas pressure sintering at a temperature of 1700~1850℃. After holding at the temperature, it is cooled in the furnace to obtain high-performance silicon nitride ceramics.

8. The preparation method according to claim 7, characterized in that, The organic matter mentioned in step S2 includes an organic monomer, a crosslinking agent, and an initiator. The organic monomer is acrylamide, the crosslinking agent is methylenebisacrylamide, and the solid content of the mixed slurry is 50-65 vol%. The vacuum degassing time is 15-30 min.

9. The preparation method according to claim 7, characterized in that, The gradient dehydration in step S3 is as follows: holding at 60-80℃ for 1-2 hours, holding at 100-120℃ for 1-2 hours, and holding at 140-160℃ for 0.5-1 hours; the defatting heating rate is 1-3℃ / min, and the defatting holding time is 2-4 hours.

10. The preparation method according to claim 7, characterized in that, In step S4, the nitrogen pressure for gas pressure sintering is 1-10 MPa, the heating rate is 5-10℃ / min, the sintering holding time is 2-4 h, and the furnace is cooled to below 200℃ before being removed from the furnace.

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