A toughened silicon carbide ceramic armor plate and a preparation method thereof

Abstract

The application discloses a toughened silicon carbide ceramic armor sheet and a preparation method thereof. The method adopts dispersion phase toughening and gel injection forming combined technology, dispersion phase toughening of the same material, and toughening and reinforcing through boric acid to realize stress dispersion, directly realize preparation of high initial density silicon carbide ceramic, and does not need complicated preparation process. The method can realize preparation of the silicon carbide ceramic armor sheet under the premise of conventional low-temperature sintering, solves the large-scale production problem of high temperature or high pressure required in the preparation process of the silicon carbide ceramic, greatly shortens the relative distance between ceramic powders, is helpful to rapid discharge of pores in the ceramic and densification of the ceramic, does not appear drying and cracking phenomenon in the preparation process, and has high forming precision of the prepared armor sheet.

Description

Technical Field

[0001] This invention relates to the field of advanced optically functional transparent ceramics preparation, specifically to a toughened silicon carbide ceramic armor sheet and its preparation method. Background Technology

[0002] Silicon carbide ceramics are widely used in mechanical seals, wear-resistant bearings, hard grinding materials, refractory materials, aerospace, and bulletproof armor due to their light weight, high thermal conductivity, high hardness, high elastic modulus, corrosion resistance, and thermal shock resistance. However, because silicon carbide is a typical C-Si covalent compound with an extremely high proportion of covalent bonds (88%), fully dense silicon carbide ceramics cannot be prepared.

[0003] Therefore, to achieve the preparation of high-density silicon carbide ceramics, researchers often employ very high sintering temperatures and combine them with one or more substances as sintering aids. While this method of controlling ceramic densification through high sintering temperatures and sintering aids has achieved the preparation of high-density silicon carbide ceramics, excessively high sintering temperatures severely damage the ceramic's brittleness, making it highly susceptible to transgranular fracture and hindering its practical application in ballistic armor. To address this, foreign researchers have used B+C or B4C+C as sintering aids for silicon carbide ceramics. Although they have successfully achieved pressureless and low-temperature sintering to prepare high-density silicon carbide ceramics, the brittleness of the ceramics remains unsatisfactory.

[0004] To meet the application requirements of silicon carbide ceramics as bulletproof armor, researchers used high-performance borides to toughen and reinforce them. However, because both boron carbide and boron ore have low surface tension and low internal atomic diffusion coefficients (the covalent bond fraction of boron carbide is over 90%), they cannot be prepared by conventional sintering, directly limiting the practical application of silicon carbide ceramics. To solve this problem, researchers used hot pressing sintering to prepare ceramics. Although the combined effects of high temperature and pressure enhance the high-temperature viscosity, diffusion migration, and plastic flowability of silicon carbide powder during sintering, achieving the goal of preparing high-density ceramics and realizing the preparation of small-grained, low-brittle ceramics, for industrial production, hot pressing sintering can only achieve ceramic preparation in the laboratory stage and cannot meet the needs of large-scale production. Summary of the Invention

[0005] To address the application needs and challenges in the mass production of high-toughness silicon carbide ceramic armor plates, this invention aims to provide a toughened silicon carbide ceramic armor plate and its preparation method. This method employs a combination of dispersed phase toughening and injection molding techniques to directly achieve the preparation of high initial density silicon carbide ceramics without the need for complex preparation processes. It enables the preparation of silicon carbide ceramic armor plates under conventional low-temperature sintering conditions, solving the problem of large-scale production requiring high temperatures or pressures in the silicon carbide ceramic preparation process. The method significantly shortens the relative spacing between ceramic powders, facilitating the rapid expulsion of internal pores and the densification of the ceramic. No drying cracking occurs during the preparation process, and the resulting armor inserts exhibit high forming precision.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a toughened silicon carbide ceramic armor sheet, comprising the following steps:

[0008] S1 Raw Material Processing: Heat treatment is performed on silicon carbide raw materials and sintering aids. The silicon carbide raw materials include silicon carbide fibers, silicon carbide particles and silicon carbide powder. The sintering aids are a combination of alumina and yttrium oxide.

[0009] S2 Raw Material Mixing: Add silicon carbide particles to a ball mill jar, add silicon carbide grinding balls, add 0.15-1.5 wt.% of dispersant (by weight of silicon carbide particles), add deionized water, and then ball mill; add 5.5-6.5 wt.% of sintering aid (by weight of silicon carbide particles), and continue ball milling; add 8-10 wt.% of nano-silicon carbide powder (by weight of silicon carbide particles), and continue ball milling, controlling the moisture content in the entire slurry system to be 12-15 wt%, to obtain slurry A;

[0010] S3 Homogenization: Filter the slurry A obtained in step S2, add silicon carbide grinding balls, add 1-3 wt% silicon carbide fiber and 0.5-0.8 wt% boric acid, and then continue ball milling; add 3-5 wt% Isobam 104 silicon carbide particles and 1-2 wt% polyethylene glycol silicon carbide particles, and continue ball milling to obtain slurry B;

[0011] S4 Armor Plate Molding: The slurry B obtained in step S3 is filtered and then vacuum degassed to obtain a ceramic slurry that can be used for armor plate molding. The obtained ceramic slurry is poured into a plaster mold and the raw blank of toughened silicon carbide ceramic armor plate is obtained after the ceramic slurry dries.

[0012] S5 Ceramic Sintering: The green body obtained in step S4 is degreased and sintered at a temperature of 800-900℃ for 5-8 hours and a sintering temperature of 1800-1900℃ for 8-15 hours to obtain a toughened silicon carbide ceramic armor sheet.

[0013] Furthermore, the raw material in step S1 is silicon carbide fiber with a carbon-silicon stoichiometric ratio of 1.03 to 1.08;

[0014] Silicon carbide particles with a particle size of 1-2 mm were selected.

[0015] Nano-sized silicon carbide powder with an average particle size of 100–300 nm was selected.

[0016] Alumina powder with an average particle size of 250–350 nm and yttrium oxide with an average particle size of 1–3 μm were selected as sintering aids.

[0017] Furthermore, the sintering aid is mixed with alumina and yttrium oxide in a ratio of 1:2.5 to 1:5.

[0018] Further, in step S1, the heat treatment includes: calcining silicon carbide raw material in a hydrogen environment for 2-4 hours at a temperature of 500-600°C; heat treating alumina in an air or oxygen environment for 2-4 hours at a temperature of 450-550°C; and heat treating yttrium oxide in an air or oxygen environment for 2-4 hours at a temperature of 800-900°C.

[0019] Furthermore, the silicon carbide grinding balls mentioned in step S2 include two types of solid grinding balls with a size of 80 mm and a size of 40 mm, with a ratio of 1:4, and the mass ratio of silicon carbide grinding balls to silicon carbide particles is 3 to 4.

[0020] Further, in step S2, the dispersant is selected from one of ammonium citrate, CE-64, and Darvan 821A.

[0021] Furthermore, in step S2, the deionized water added during the silicon carbide particle grinding stage contains 10 wt% of the silicon carbide particle mass.

[0022] Furthermore, in step S2, the first ball milling time is 48–72 h, the second ball milling time is 12–24 h, and the third ball milling time is 36–48 h.

[0023] Furthermore, in step S3, the first ball milling time is 16-32 hours, and the second ball milling time is 18-30 hours.

[0024] Secondly, the present invention provides a toughened silicon carbide ceramic armor sheet, which is prepared by the above-described preparation method.

[0025] The beneficial effects of this invention are as follows:

[0026] (1) This application uses a combination of dispersed phase toughening and injection molding technology to prepare silicon carbide ceramic armor plates with high initial density, which greatly shortens the relative spacing between ceramic powders, helps silicon carbide ceramics to discharge pores and sinter densify during the sintering process, and no drying cracking occurs during the preparation process. The prepared armor inserts have high forming precision.

[0027] (2) Compared with existing similar products, the silicon carbide high ceramic prepared in this application has the characteristics of high strength and good toughness. It uses the same type of silicon carbide fiber for toughening, and there is no sintering cracking caused by inconsistent expansion coefficients. At the same time, boric acid acts on the silicon carbide surface to form a protective film, avoiding the formation of liquid phase melting between silicon carbide fibers and silicon carbide powder. The silicon carbide ceramic has a uniform structure and stable distribution of silicon carbide fibers, and has high mechanical properties.

[0028] (3) This application can be applied without complicated machining, and can realize the preparation of silicon carbide ceramic armor sheets under the premise of conventional low temperature sintering, solving the problem of large-scale production that requires high temperature or high pressure in the preparation process of silicon carbide ceramics.

[0029] (4) This application uses commercial micro-nano powder, which effectively solves the agglomeration phenomenon in the ceramic powder preparation process; at the same time, it uses powder particles of different sizes to achieve particle toughening of the material, increases the branching of crack turning, and improves the impact energy absorption capacity of ceramics.

[0030] (5) Compared with the existing dispersed phase toughening method that utilizes the pinning effect of heterogeneous ion second phase materials, this application adopts a dispersed phase-induced composite toughening method, which overcomes the internal residual strain energy of the ceramic itself; and utilizes fiber toughening and whisker toughening to increase the friction force of ceramic cracking, thereby achieving the offsetting of external stress of cracks, passivating crack propagation, and ultimately achieving the strengthening of ceramics. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a SEM microstructure image of a toughened silicon carbide ceramic armor sheet prepared in Example 1 of the present invention.

[0033] Figure 2 The SEM image of the surface of a toughened silicon carbide ceramic armor sheet after corrosion is shown in Example 1 of this invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0035] Example 1

[0036] A toughened silicon carbide ceramic armor plate, the preparation method of which includes the following steps:

[0037] (1) Raw material selection: commercial silicon carbide fiber with a carbon-silicon stoichiometry ratio of 1.04 was selected; high-purity silicon carbide particles with a particle size of 1.5 mm were selected; high-purity nano-silicon carbide powder with an average particle size of 200 nm was selected; high-purity alumina powder with an average particle size of 300 nm and high-purity yttrium oxide with an average particle size of 2 μm were selected as sintering aids; commercial high-purity boric acid was selected.

[0038] (2) Raw material processing: The above raw materials are subjected to heat treatment, namely, silicon carbide particles and silicon carbide powder are calcined in a hydrogen environment for 3 hours at a temperature of 550°C; alumina is subjected to heat treatment in an air atmosphere for 3 hours at a temperature of 550°C; yttrium oxide is subjected to heat treatment in an air atmosphere for 3 hours at a temperature of 800°C.

[0039] (3) Raw material mixing: Add silicon carbide particles to a drum ball mill jar, add silicon carbide grinding balls, the amount of grinding balls added is 4 times the mass of silicon carbide particles, wherein the ratio of 80mm grinding balls to 40mm grinding balls is 1:4, add 0.15wt.% of dispersant CE-64 of silicon carbide particles, add 10wt.% of deionized water of silicon carbide particles, and then ball mill for 72h; add 6.0wt% of sintering aid of silicon carbide particles, the sintering aid is a mixture of alumina and yttrium oxide, the ratio of alumina:yttrium oxide is 1:2.5, and continue ball milling for 24h; add 8wt% of nano silicon carbide powder of silicon carbide particles, and continue ball milling for 48h, controlling the moisture content in the entire slurry system to be 14.4wt%;

[0040] (4) Homogenization: The slurry obtained in step (3) is filtered, grinding balls are added, 2.0 wt% silicon carbide fiber and 0.6 wt% boric acid are added, and then ball milling is continued for 24 hours; 3.0 wt% Isobam 104 silicon carbide particles and 1.5 wt% polyethylene glycol silicon carbide particles are added, and ball milling is continued for 24 hours to obtain the slurry;

[0041] (5) Armor plate molding: The slurry obtained in step (4) is filtered and then vacuum degassed to obtain a ceramic slurry that can be used for armor plate molding. The obtained slurry is poured into a plaster mold and the raw blank of silicon carbide ceramic armor plate is obtained after the slurry dries.

[0042] (6) Ceramic sintering: The blank of the silicon carbide ceramic armor sheet obtained in step four (5) is degreased and sintered. The degreasing temperature is 800℃ and the holding time is 6h. The sintering temperature is 1830℃ and the holding time is 8h. The toughened silicon carbide ceramic armor sheet of the present invention can be obtained.

[0043] Example 2

[0044] A toughened silicon carbide ceramic armor plate, the preparation method of which includes the following steps:

[0045] (1) Raw material selection: commercial silicon carbide fiber with a carbon-silicon stoichiometry ratio of 1.08 was selected; high-purity silicon carbide particles with a particle size of 1.5 mm were selected; high-purity nano-silicon carbide powder with an average particle size of 200 nm was selected; high-purity alumina powder with an average particle size of 300 nm and high-purity yttrium oxide with an average particle size of 2 μm were selected as sintering aids; commercial high-purity boric acid was selected.

[0046] (2) Raw material processing: The above raw materials are subjected to heat treatment, namely, silicon carbide particles and silicon carbide powder are calcined in a hydrogen environment for 3 hours at a temperature of 600°C; alumina is subjected to heat treatment in an air atmosphere for 3 hours at a temperature of 500°C; yttrium oxide is subjected to heat treatment in an air atmosphere for 3 hours at a temperature of 900°C.

[0047] (3) Raw material mixing: Add silicon carbide particles to a drum ball mill jar, add silicon carbide grinding balls, the amount of grinding balls added is 4 times the mass of silicon carbide particles, the ratio of 80mm grinding balls to 40mm grinding balls is 1:4, add 0.15wt.% of ammonium citrate dispersant of silicon carbide particles, add 10wt.% of deionized water of silicon carbide particles, and then ball mill for 60h; add 6.0wt% of sintering aid of silicon carbide particles, the sintering aid is a mixture of alumina and yttrium oxide, the ratio of alumina:yttrium oxide is 1:5, and continue ball milling for 16h; add 10wt% of nano silicon carbide powder of silicon carbide particles, and continue ball milling for 40h, controlling the moisture content in the entire slurry system to be 15wt%;

[0048] (4) Homogenization: Filter the slurry obtained in step (3), add grinding balls, add 2.0 wt% silicon carbide fiber and 0.8 wt% boric acid, and then continue ball milling for 24 hours; add 1.0 wt% Isobam 104 silicon carbide particles and 1.5 wt% polyethylene glycol silicon carbide particles, and continue ball milling for 24 hours to obtain the slurry;

[0049] (5) Armor plate molding: The slurry obtained in step (4) is filtered and then vacuum degassed to obtain a ceramic slurry that can be used for armor plate molding. The obtained slurry is poured into a plaster mold and the raw blank of silicon carbide ceramic armor plate is obtained after the slurry dries.

[0050] (6) Ceramic sintering: The blank of the silicon carbide ceramic armor sheet obtained in step four (5) is degreased and sintered at a degreasing temperature of 900°C and a holding time of 6h, and a sintering temperature of 1850°C and a holding time of 8h, so as to obtain the toughened silicon carbide ceramic armor sheet of the present invention.

[0051] Example 3

[0052] A toughened silicon carbide ceramic armor plate, the preparation method of which includes the following steps:

[0053] (1) Raw material selection: commercial silicon carbide fiber with a carbon-silicon stoichiometry ratio of 1.03 was selected; high-purity silicon carbide particles with a particle size of 1.5 mm were selected; high-purity nano-silicon carbide powder with an average particle size of 200 nm was selected; high-purity alumina powder with an average particle size of 300 nm and high-purity yttrium oxide with an average particle size of 2 μm were selected as sintering aids; commercial high-purity boric acid was selected.

[0054] (2) Raw material processing: The above raw materials are subjected to heat treatment, namely, silicon carbide particles and silicon carbide powder are calcined in a hydrogen atmosphere for 4 hours at a temperature of 600°C; alumina is subjected to heat treatment in an air atmosphere for 3 hours at a temperature of 550°C; yttrium oxide is subjected to heat treatment in an air atmosphere for 3 hours at a temperature of 900°C.

[0055] (3) Raw material mixing: Add silicon carbide particles to a drum ball mill jar, add silicon carbide grinding balls, the amount of grinding balls added is 4 times the mass of silicon carbide particles, wherein the ratio of 80mm grinding balls to 40mm grinding balls is 1:4, add 1.0wt.% ammonium citrate dispersant of silicon carbide particles, add 10wt.% deionized water of silicon carbide particles, and then ball mill for 60h; add 6.5wt% sintering aid of silicon carbide particles, the sintering aid is a mixture of alumina and yttrium oxide, the ratio of alumina:yttrium oxide is 1:5, and continue ball milling for 16h; add 10wt% nano silicon carbide powder of silicon carbide particles, and continue ball milling for 40h, controlling the moisture content in the entire slurry system to be 15wt%;

[0056] (4) Homogenization: The slurry obtained in step (3) is filtered, grinding balls are added, 2.0 wt% silicon carbide fiber and 0.8 wt% boric acid are added, and then ball milling is continued for 24 hours; 5.0 wt% Isobam 104 silicon carbide particles and 2.0 wt% polyethylene glycol silicon carbide particles are added, and ball milling is continued for 24 hours to obtain the slurry;

[0057] (5) Armor plate molding: The slurry obtained in step (4) is filtered and then vacuum degassed to obtain a ceramic slurry that can be used for armor plate molding. The obtained slurry is poured into a plaster mold and the raw blank of silicon carbide ceramic armor plate is obtained after the slurry dries.

[0058] (6) Ceramic sintering: The blank of the silicon carbide ceramic armor sheet obtained in step four (5) is degreased and sintered at a degreasing temperature of 900°C and a holding time of 6h, and a sintering temperature of 1850°C and a holding time of 8h, so as to obtain the toughened silicon carbide ceramic armor sheet of the present invention.

[0059] Table 1 shows the performance results of Examples 1-3 of the present invention.

[0060]

[0061] This invention employs a combination of dispersed phase toughening and injection molding techniques to directly achieve the preparation of high initial density silicon carbide ceramics. Boric acid acts on the silicon carbide surface to form a protective film and promotes the transformation of silicon carbide fibers into silicon carbide whiskers, while preventing the formation of liquid phase melting between silicon carbide fibers and silicon carbide powder. Since relatively excessive boric acid will accumulate around the whiskers, it may form microcracks, thereby achieving stress dispersion.

[0062] Compared to existing dispersed phase toughening methods that utilize the pinning effect of dissimilar ion second-phase materials, this invention belongs to a dispersed phase-induced composite toughening method. Firstly, it employs dispersed phase toughening of the same material, using different crystal structures of the same material as the second phase to achieve phase transformation toughening and overcome the internal residual strain energy of the ceramic. Simultaneously, it utilizes powder particles of different sizes to achieve particle toughening (particle gradation effect), increasing crack branching and enhancing the ceramic's impact energy absorption capacity. Furthermore, it utilizes fiber toughening and whisker toughening to increase the frictional force during ceramic cracking, achieving the offsetting of external stress on the crack, passively inhibiting crack propagation, and ultimately strengthening the ceramic.

[0063] Figure 1 This is a SEM micrograph of a toughened silicon carbide ceramic armor sheet prepared in Example 1 of the present invention. Figure 1 It can be seen that the silicon carbide fibers are microscopically and stably distributed in the ceramic, without delamination, cracking, or pores.

[0064] Figure 2 The image shows a SEM image of the surface of a toughened silicon carbide ceramic armor sheet prepared in Example 1 of this invention after corrosion. The sample surface has a uniform structure and no abnormal grain growth, indicating that the sample has good performance.

[0065] This invention eliminates the need for cumbersome and complex preparation processes, enabling the preparation of silicon carbide ceramic armor plates under conventional low-temperature sintering conditions. The prepared armor plates exhibit high forming precision, as shown in Table 1. The silicon carbide ceramic plates possess characteristics such as high strength and good toughness, uniform structure, and stable distribution of silicon carbide fibers, resulting in high mechanical properties.

[0066] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for producing a toughened silicon carbide ceramic armor plate, characterized by, The method comprises the following steps: S1 raw material treatment: heat treatment is performed on the silicon carbide raw material and sintering aid, the silicon carbide raw material comprises silicon carbide fibers, silicon carbide particles and silicon carbide powder, and the sintering aid is a combination of both aluminum oxide and yttrium oxide; In step S1, the silicon carbide raw material is selected to be silicon carbide fibers with a stoichiometric ratio of carbon to silicon of 1.03-1.

08. The silicon carbide particles with a particle size of 1-2 mm are selected. The nano-silicon carbide powder with an average particle size of 100-300 nm is selected. S2 raw material mixing: the silicon carbide particles are added into a ball mill tank, silicon carbide grinding balls are added, a dispersant with a mass of 0.15-1.5 wt.% of the silicon carbide particles is added, deionized water is added, and then ball milling is performed; a sintering aid with a mass of 5.5-6.5 wt% of the silicon carbide particles is added, and ball milling is continued; nano-silicon carbide powder with a mass of 8-10 wt% of the silicon carbide particles is added, and ball milling is continued, so that the water content in the whole slurry system is controlled to be 12-15 wt%, and slurry A is obtained; S3 uniform slurry treatment: the slurry A obtained in step S2 is filtered, silicon carbide grinding balls are added, silicon carbide fibers with a mass of 1-3 wt% of the silicon carbide particles and boric acid with a mass of 0.5-0.8 wt% of the silicon carbide particles are added, and then ball milling is continued; Isobam 104 with a mass of 3-5 wt% of the silicon carbide particles is added, polyethylene glycol with a mass of 1-2 wt% of the silicon carbide particles is added, and ball milling is continued, and slurry B is obtained; S4 green sheet forming: the slurry B obtained in step S3 is filtered, and then vacuum degassing is performed, so that a ceramic slurry for green sheet forming is obtained, the ceramic slurry is poured into a gypsum mold, and after the ceramic slurry is dried, a green body of the toughened silicon carbide ceramic armor sheet is obtained; S5 ceramic sintering: the green body obtained in step S4 is subjected to debinding and sintering, the debinding temperature is 800-900 ℃, the holding time is 5-8 h, the sintering temperature is 1800-1900 ℃, and the holding time is 8-15 h, and thus the toughened silicon carbide ceramic armor sheet is obtained.

2. The method of claim 1, wherein the toughened silicon carbide ceramic armor plate is prepared by the steps of: mixing a silicon carbide powder with a binder and a solvent to form a mixture; and molding the mixture into a plate shape. The aluminum oxide powder with an average particle size of 250-350 nm and the yttrium oxide with an average particle size of 1-3 μm are selected as the sintering aid.

3. The method for preparing a toughened silicon carbide ceramic armor sheet as described in claim 2, characterized in that, The mixing ratio of the sintering aid is 1:2.5-1:5 of aluminum oxide to yttrium oxide.

4. The method for preparing a toughened silicon carbide ceramic armor sheet as described in claim 1, characterized in that, In step S1, the heat treatment comprises calcining the silicon carbide raw material in a hydrogen atmosphere, the heat treatment time is 2-4 h, and the heat treatment temperature is 500-600 ℃; the aluminum oxide is heat treated in an air or oxygen atmosphere, the heat treatment time is 2-4 h, and the heat treatment temperature is 450-550 ℃; and the yttrium oxide is heat treated in an air or oxygen atmosphere, the heat treatment time is 2-4 h, and the heat treatment temperature is 800-900 ℃.

5. The method of claim 1, wherein the toughened silicon carbide ceramic armor plate is prepared by the steps of: mixing silicon carbide powder, a binder, and a solvent to form a slurry; coating a surface of a substrate with the slurry; drying the slurry; and sintering the dried slurry. In step S2, the dispersant is selected from one of ammonium citrate, CE-64 and Darvan 821A.

6. The method of claim 1, wherein the toughened silicon carbide ceramic armor plate is prepared by the steps of: mixing silicon carbide powder, a binder, and a solvent to form a slurry; coating a surface of a substrate with the slurry; drying the slurry; and sintering the dried slurry. In step S2, the silicon carbide grinding balls comprise two kinds of solid grinding balls with a size of 80 mm and a size of 40 mm, the ratio of the two kinds of grinding balls is 1:4, and the mass ratio of the silicon carbide grinding balls to the silicon carbide particles is 3-4.

7. The method of claim 1, wherein the toughened silicon carbide ceramic armor plate is prepared by the steps of: mixing silicon carbide powder, a binder, and a solvent to form a slurry; coating a surface of a substrate with the slurry; drying the slurry; and sintering the dried slurry. The deionized water added in the silicon carbide particle grinding stage in step S2 is 10-12 wt% of the mass of the silicon carbide particles.

8. The method of claim 1, wherein the toughened silicon carbide ceramic armor plate is prepared by the steps of: mixing silicon carbide powder, a binder, and a solvent to form a slurry; coating a substrate with the slurry; drying the coated substrate; and sintering the dried coated substrate. In step S2, the first ball milling time is 48-72 h, the second ball milling time is 12-24 h, and the third ball milling time is 36-48 h.

9. The method of claim 1, wherein the toughened silicon carbide ceramic armor plate is prepared by the steps of: mixing silicon carbide powder, a binder, and a solvent to form a slurry; pouring the slurry into a mold; drying the slurry; and sintering the dried slurry. In step S3, the first ball milling time is 16-32 h, and the second ball milling time is 18-30 h.

10. A toughened silicon carbide ceramic armor sheet characterized by, The preparation method of any one of claims 1-9 is used.

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