High-strength and high-anti-crack ceramic and its preparation method

Abstract

The application relates to the technical field of ceramics, and discloses high-strength and high-anti-crack ceramic and a preparation method thereof. The ceramic significantly improves the strength and anti-crack performance of traditional ceramic through innovative material modification and process optimization. First, the surface of nano-titanium dioxide is modified by using double-end carboxyl polyquaternary ammonium salt to obtain polyquaternary ammonium salt modified titanium dioxide; then, quartz, clay, feldspar, aluminum oxide, talcum powder and modified titanium dioxide are mixed and ball milled, and the ceramic is prepared through sintering after forming. Through the interface modification effect of the double-end carboxyl polyquaternary ammonium salt, the nano-titanium dioxide is uniformly dispersed and firmly combined with the matrix, effectively hinders crack propagation, the obtained ceramic has excellent bending strength and compressive strength, the application field of the ceramic product is widened, and the ceramic has wide market application prospects.

Description

Technical Field

[0001] This invention relates to the field of ceramic technology, specifically to a high-strength, crack-resistant ceramic and its preparation method. Background Technology

[0002] Ceramic materials, due to their superior properties such as high strength, high hardness, high temperature resistance, and corrosion resistance, have wide applications in aerospace, machinery manufacturing, electronic devices, biomedicine, sanitary ware, and daily-use ceramics. However, the inherent brittleness and poor crack resistance of traditional ceramic materials limit their use under dynamic loads. Especially under high temperature, high stress, or thermal cycling conditions, ceramics are prone to microcracks due to internal stress concentration, which propagate rapidly, leading to material fracture failure. Therefore, developing a ceramic material that combines high strength and excellent crack resistance has become a current research hotspot in the ceramics field.

[0003] Currently, toughening modification is a common method to improve the crack resistance of ceramics. For example, phase transformation toughening, fiber / whisker reinforcement, and nanoparticle dispersion strengthening are used to inhibit crack propagation and improve compressive strength and crack resistance.

[0004] Nano-titanium dioxide is resistant to acids, alkalis, and high temperatures, and possesses excellent mechanical properties and dispersibility, making it suitable for high-temperature sintering processes in ceramics and enhancing their wear resistance. When added to ceramics, nano-titanium dioxide can be uniformly dispersed within the ceramic matrix, enhancing mechanical properties such as flexural strength and optimizing the microstructure. However, the tendency of nanoparticles to agglomerate affects uniform dispersion, and their high cost limits their industrial application.

[0005] In existing technologies, single toughening methods often struggle to simultaneously achieve high strength and crack resistance, and some modifying agents (such as rare earth oxides) are costly, hindering commercial applications. Therefore, there is an urgent need to develop a low-cost, simple process that can synergistically improve the strength and crack resistance of ceramics to meet industrial application requirements. The purpose of this invention is to provide a method for preparing high-strength, crack-resistant ceramics by modifying the surface of nano-titanium dioxide, thereby significantly improving the crack resistance of the ceramic while maintaining high strength, thus overcoming the shortcomings of existing technologies. Summary of the Invention

[0006] (a) Technical problems to be solved:

[0007] To address the shortcomings of existing technologies, this invention provides a high-strength, crack-resistant ceramic and its preparation method, solving problems such as low ceramic strength and poor crack resistance.

[0008] (II) Technical Solution:

[0009] A method for preparing a high-strength, crack-resistant ceramic is as follows:

[0010] Step S1: Add ethanol, deionized water, double-terminated carboxyl polyquaternary ammonium salt, and nano-titanium dioxide to a flask, heat and stir, filter, wash with ethanol and deionized water, and dry to obtain polyquaternary ammonium salt modified titanium dioxide.

[0011] Step S2: Mix quartz, clay, feldspar, alumina, talc, polyquaternium-modified titanium dioxide, polyvinyl alcohol, and deionized water, and then ball mill the mixture to obtain a slurry. Pour the slurry into a mold, dry it, press it into a green body, place it in a sintering furnace, raise the temperature to 1200-1350℃ at a heating rate of 5-10℃ / min, hold it at that temperature for 3-5 hours, and then cool it to obtain a high-strength, crack-resistant ceramic.

[0012] Preferably, in step S1, the ratio of double-ended carboxyl polyquaternary ammonium salt to nano-titanium dioxide is (8-20)g:100g.

[0013] Preferably, the heating temperature in step S1 is 80-90℃, and the stirring time is 3 hours.

[0014] Preferably, in step S2, the ratio of quartz, clay, feldspar, alumina, talc, polyquaternium-modified titanium dioxide, and polyvinyl alcohol is 100g:(75-90)g:(28-35)g:(3-8)g:(15-35)g:(1-8)g:(1.2-1.7)g.

[0015] Preferably, the ball milling time in step S2 is 2-3 hours, and the ball milling speed is 500-800 r / min.

[0016] The preferred method for preparing the double-terminated carboxyl polyquaternary ammonium salt is as follows:

[0017] (1) Add 1,4-dioxane in a ratio of 100 mol:(0.1-0.13) mol:(0.03-0.05) mol of dimethylaminoethyl methacrylate (CAS No. 2867-47-2), 2,2'-[thiocarbonyl(sulfur)]bis[2-methylpropionic acid] (CAS No. 355120-40-0), and 4,4'-azobis(4-cyanopentanoic acid) (CAS No. 2638-94-0) to a flask. After stirring, purge with nitrogen gas, heat to 85-100℃, and reflux for 30-90 min. After the reaction, pour the solution into petroleum ether to precipitate, filter, wash with ethyl acetate, and dry to obtain carboxyl-terminated poly(dimethylaminoethyl methacrylate). The preparation reaction formula is:

[0018]

[0019] (2) Add ethanol, dimethylaminoethyl methacrylate (dimethylaminoethyl methacrylate) with a carboxyl-terminated polymethyl methacrylate in a ratio of 100g:(15-28)g, and bromoalkane to a flask. Heat to 70-80℃, stir and react for 18-24h. After cooling, filter, wash the precipitate with ethanol, and dry to obtain the dicarboxyl-terminated polyquaternary ammonium salt. The molecular formula of the bromoalkane is Br-C n H 2n+1 n is 2-4. The preparation reaction formula is:

[0020]

[0021] (III) Beneficial Technical Effects:

[0022] Using 2,2'-[thiocarbonyl(sulfur)]bis[2-methylpropionic acid] as a chain transfer agent and 4,4'-azobis(4-cyanopentanoic acid) as an initiator, dimethylaminoethyl methacrylate was subjected to a RAFT reversible addition-fragmentation chain transfer radical polymerization reaction to obtain carboxyl-terminated polydimethylaminoethyl methacrylate. Then, the tertiary amine group was subjected to a quaternization reaction with a brominated alkane to obtain a bi-carboxyl-terminated polyquaternary ammonium salt. The bi-carboxyl groups of the polyquaternary salt interact with the hydroxyl groups on the surface of nano-titanium dioxide, thereby achieving surface modification of nano-titanium dioxide. Using it as an additive, it was mixed with quartz, feldspar, etc., and after sintering and other processes, high-strength and crack-resistant ceramics were obtained.

[0023] The high-strength, crack-resistant ceramic prepared by this invention successfully solves the technical problems of high brittleness and poor crack resistance in traditional ceramics through innovative material modification and process optimization. This invention uses a double-terminated carboxyl polyquaternary ammonium salt to modify the surface of nano-titanium dioxide, introducing polymer molecular chains containing quaternary ammonium salts onto the surface of nano-titanium dioxide. The quaternary ammonium salts are adsorbed onto the surfaces of quartz, clay, and feldspar through electrostatic interactions, and react with the Al₂O₃ within them. 3+ Fe 3+ Ca 2+ The substitution between high-valence cations improves the compatibility and interfacial bonding between titanium dioxide and ceramic groups, effectively hindering crack propagation. This gives the ceramic both high strength and high toughness, broadening the application fields of ceramic products and providing a promising market prospect. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described below with reference to examples, but the present invention is not limited to the scope of the examples described herein.

[0025] Example 1: The preparation method of high-strength and crack-resistant ceramics is as follows:

[0026] (1) Add 40 mL of 1,4-dioxane, 40 mmol of dimethylaminoethyl methacrylate, 0.04 mmol of 2,2'-[thiocarbonyl(sulfur)]bis[2-methylpropionic acid], and 0.012 mmol of 4,4'-azobis(4-cyanopentanoic acid) to a flask, stir, introduce nitrogen gas, heat to 85 °C, reflux for 90 min, pour the solution into 40 mL of petroleum ether for precipitation, filter, wash with 40 mL of ethyl acetate, and dry to obtain dimethylaminoethyl methacrylate with carboxyl-terminated ends.

[0027] (2) Add 40 mL of ethanol, 5 g of dimethylaminoethyl methacrylate with carboxyl-terminated polymethyl methacrylate and 0.75 g of bromoethane to a flask, heat to 80 °C, stir and react for 18 h, cool and filter, wash the precipitate with 40 mL of ethanol, dry and obtain dimethyl methacrylate with carboxyl-terminated polyquaternary ammonium salt.

[0028] (3) Add 15 mL of ethanol, 60 mL of deionized water, 2.4 g of double-terminated carboxyl polyquaternary ammonium salt and 30 g of nano titanium dioxide to the flask, heat and stir at 90 °C for 3 h, filter, wash with ethanol and deionized water, and dry to obtain polyquaternary ammonium salt modified titanium dioxide.

[0029] (4) Mix 150 mL of deionized water, 2 kg of quartz, 1.5 kg of clay, 560 g of feldspar, 60 g of alumina, 300 g of talc, 20 g of polyquaternary ammonium salt modified titanium dioxide and 24 g of polyvinyl alcohol, and then ball mill them in a ball mill at a speed of 500 r / min for 2 h to obtain a slurry. Pour the slurry into a mold, dry it and press it into a green body. Place it in a sintering furnace and heat it to 1350 °C at a heating rate of 10 °C / min. Hold it at the temperature for 5 h and cool it to obtain a high-strength and crack-resistant ceramic.

[0030] Example 2: The preparation method of high-strength and crack-resistant ceramics is as follows:

[0031] (1) Add 40 mL of 1,4-dioxane, 40 mmol of dimethylaminoethyl methacrylate, 0.052 mmol of 2,2'-[thiocarbonyl(sulfur)]bis[2-methylpropionic acid], and 0.02 mmol of 4,4'-azobis(4-cyanopentanoic acid) to a flask, stir, introduce nitrogen gas, heat to 100 °C, reflux for 30 min, pour the solution into 40 mL of petroleum ether for precipitation, filter, wash with 40 mL of ethyl acetate, and dry to obtain dimethylaminoethyl methacrylate with carboxyl-terminated ends.

[0032] (2) Add 40 mL of ethanol, 5 g of dimethylaminoethyl methacrylate with carboxyl-terminated polymethyl methacrylate and 1.4 g of bromopropane to a flask, heat to 70 °C, stir and react for 24 h, cool and filter, wash the precipitate with 40 mL of ethanol, dry and obtain dimethyl methacrylate with carboxyl-terminated polyquaternary ammonium salt.

[0033] (3) Add 15 mL of ethanol, 60 mL of deionized water, 6 g of double-terminated carboxyl polyquaternary ammonium salt and 30 g of nano titanium dioxide to a flask, heat and stir at 80 °C for 3 h, filter, wash with ethanol and deionized water, and dry to obtain polyquaternary ammonium salt modified titanium dioxide.

[0034] (4) Mix 150mL of deionized water, 2kg of quartz, 1.8kg of clay, 700g of feldspar, 160g of alumina, 700g of talc, 160g of polyquaternary ammonium salt modified titanium dioxide and 34g of polyvinyl alcohol, and then ball mill them in a ball mill at a speed of 800r / min for 3h to obtain a slurry. Pour the slurry into a mold, dry it and press it into a green body. Place it in a sintering furnace and heat it to 1300℃ at a heating rate of 5℃ / min. Hold it at the temperature for 3h and cool it to obtain a high-strength and crack-resistant ceramic.

[0035] Example 3: The preparation method of high-strength and crack-resistant ceramics is as follows:

[0036] (1) Add 40 mL of 1,4-dioxane, 40 mmol of dimethylaminoethyl methacrylate, 0.046 mmol of 2,2'-[thiocarbonyl(sulfur)]bis[2-methylpropionic acid], and 0.016 mmol of 4,4'-azobis(4-cyanopentanoic acid) to a flask, stir, introduce nitrogen gas, heat to 62 °C, reflux for 60 min, pour the solution into 40 mL of petroleum ether for precipitation, filter, wash with 40 mL of ethyl acetate, and dry to obtain dimethylaminoethyl methacrylate with carboxyl-terminated ends.

[0037] (2) Add 40 mL of ethanol, 5 g of dimethylaminoethyl methacrylate with carboxyl-terminated polymethyl methacrylate and 1.075 g of bromobutane to a flask, heat to 75 °C, stir and react for 21 h, cool and filter, wash the precipitate with 40 mL of ethanol, dry and obtain dimethyl methacrylate with carboxyl-terminated polyquaternary ammonium salt.

[0038] (3) Add 15 mL of ethanol, 60 mL of deionized water, 4.2 g of double-terminated carboxyl polyquaternary ammonium salt and 30 g of nano titanium dioxide to a flask, heat and stir at 85 °C for 3 h, filter, wash with ethanol and deionized water, and dry to obtain polyquaternary ammonium salt modified titanium dioxide.

[0039] (4) Mix 50 mL of deionized water, 2 kg of quartz, 1.65 g of clay, 630 g of feldspar, 110 g of alumina, 500 g of talc, 90 g of polyquaternary ammonium salt modified titanium dioxide and 30 g of polyvinyl alcohol, and then ball mill them in a ball mill at a speed of 650 r / min for 2.5 h to obtain a slurry. Pour the slurry into a mold, dry it and press it into a green body. Place it in a sintering furnace and heat it to 1200 °C at a heating rate of 7 °C / min. Hold it at the temperature for 4 h and cool it to obtain a high-strength and crack-resistant ceramic.

[0040] Example 4: The preparation method of high-strength and crack-resistant ceramics is as follows:

[0041] (1) Add 40 mL of 1,4-dioxane, 1 mol of dimethylaminoethyl methacrylate, 0.0325 mmol of 2,2'-[thiocarbonyl(sulfur)]bis[2-methylpropionic acid], and 0.0125 mmol of 4,4'-azobis(4-cyanopentanoic acid) to a flask, stir, introduce nitrogen gas, heat to 85 °C, reflux for 70 min, pour the solution into 40 mL of petroleum ether for precipitation, filter, wash with 40 mL of ethyl acetate, and dry to obtain carboxyl-terminated poly(dimethylaminoethyl methacrylate).

[0042] (2) Add 40 mL of ethanol, 5 g of dimethylaminoethyl methacrylate with carboxyl-terminated polymethyl methacrylate and 0.75 g of bromoethane to a flask, heat to 70 °C, stir and react for 24 h, cool and filter, wash the precipitate with 40 mL of ethanol, dry and obtain dimethyl methacrylate with carboxyl-terminated polyquaternary ammonium salt.

[0043] (3) Add 15 mL of ethanol, 60 mL of deionized water, 2.4 g of double-terminated carboxyl polyquaternary ammonium salt and 30 g of nano titanium dioxide to the flask, heat and stir at 90 °C for 3 h, filter, wash with 15 mL of ethanol and 60 mL of deionized water, and dry to obtain polyquaternary ammonium salt modified titanium dioxide.

[0044] (4) Mix 50 mL of deionized water, 2 kg of quartz, 1.5 kg of clay, 560 g of feldspar, 160 g of alumina, 300 g of talc, 160 g of polyquaternary ammonium salt modified titanium dioxide and 34 g of polyvinyl alcohol, and then ball mill them in a ball mill at a speed of 800 r / min for 2 h to obtain a slurry. Pour the slurry into a mold, dry it and press it into a green body. Place it in a sintering furnace and heat it to 1350 °C at a heating rate of 10 °C / min. Hold it at the temperature for 5 h and cool it to obtain a high-strength and crack-resistant ceramic.

[0045] The difference between Comparative Example 1 and Example 1 is that no polyquaternium salt modified titanium dioxide is added.

[0046] Mix 150 mL of deionized water, 2 kg of quartz, 1.5 kg of clay, 560 g of feldspar, 60 g of alumina, 300 g of talc, and 24 g of polyvinyl alcohol. Then, ball mill the mixture at 500 r / min for 2 hours to obtain a slurry. Pour the slurry into a mold, dry it, press it into a green body, place it in a sintering furnace, raise the temperature to 1350°C at a heating rate of 10°C / min, hold it at that temperature for 5 hours, and then cool it to obtain ceramic.

[0047] Comparative Example 2 uses nano-titanium dioxide instead of polyquaternary ammonium salt modified titanium dioxide.

[0048] Mix 150 mL of deionized water, 2 kg of quartz, 1.5 kg of clay, 560 g of feldspar, 60 g of alumina, 300 g of talc, 20 g of nano-titanium dioxide, and 24 g of polyvinyl alcohol. Then, ball mill the mixture at 500 r / min for 2 h to obtain a slurry. Pour the slurry into a mold, dry it, press it into a green body, place it in a sintering furnace, raise the temperature to 1350 °C at a heating rate of 10 °C / min, hold it at that temperature for 5 h, and then cool it to obtain ceramic.

[0049] Comparative Example 3 used dimethylaminoethyl methacrylate with dual-carboxyl groups instead of dimethylaminoethyl methacrylate with dual-carboxyl groups.

[0050] (1) Add 15 mL of ethanol, 60 mL of deionized water, 2.4 g of dimethylaminoethyl methacrylate with carboxyl groups and 30 g of nano titanium dioxide to a flask, heat and stir at 90 °C for 3 h, filter, wash with ethanol and deionized water, and dry to obtain modified titanium dioxide.

[0051] (2) Mix 150mL of deionized water, 2kg of quartz, 1.5kg of clay, 560g of feldspar, 60g of alumina, 300g of talc, 20g of modified titanium dioxide and 24g of polyvinyl alcohol, and then ball mill them in a ball mill at a speed of 500r / min for 2h to obtain a slurry. Pour the slurry into a mold, dry it and press it into a green body. Place it in a sintering furnace and heat it to 1350℃ at a heating rate of 10℃ / min. Hold it at the temperature for 5h and then cool it to obtain ceramic.

[0052] Comparative Example 4 used stearic acid-modified titanium dioxide instead of polyquaternary ammonium salt-modified titanium dioxide.

[0053] (1) Add 120 mL of ethanol, 120 mL of deionized water, 3.6 g of stearic acid and 30 g of nano titanium dioxide to a flask, heat and stir at 90 °C for 3 h, grind and sieve to obtain stearic acid modified titanium dioxide.

[0054] (2) Mix 150mL of deionized water, 2kg of quartz, 1.5kg of clay, 560g of feldspar, 60g of alumina, 300g of talc, 20g of stearic acid-modified titanium dioxide and 24g of polyvinyl alcohol, and then ball mill them in a ball mill at a speed of 500r / min for 2h to obtain a slurry. Pour the slurry into a mold, dry it and press it into a green body. Place it in a sintering furnace and heat it to 1350℃ at a heating rate of 10℃ / min. Hold it at the temperature for 5h and then cool it to obtain ceramics.

[0055] The strength of ceramics is tested according to GB / T 4740-2024.

[0056] Table 1 Performance Tests of Ceramics

[0057] Flexural strength / MPa Compressive strength (MPa) Example 1 54.2 67.3 Example 2 72.3 85.6 Example 3 64.4 94.2 Example 4 70.5 81.3 Comparative Example 1 43.1 56.8 Comparative Example 2 45.8 58.2 Comparative Example 3 48.6 62.5 Comparative Example 4 49.7 64.0

[0058] Example 1 uses polyquaternary ammonium salt modified titanium dioxide as a reinforcing phase, achieving a flexural strength of 54.2 MPa and a compressive strength of 67.3 MPa, significantly superior to traditional ceramics. The core of this performance improvement lies in the optimization of crack resistance: the modified titanium dioxide forms a strong bond with the ceramic matrix through the interfacial interaction of the double-terminated carboxyl polyquaternary ammonium salt, and the uniformly dispersed nanoparticles effectively hinder crack propagation under stress. When the ceramic is subjected to bending or impact loads, the crack tip encounters the uniformly distributed modified titanium dioxide particles, and their strong interfacial bonding force forces the crack to deflect or branch, consuming fracture energy and thus significantly improving the compressive strength. Simultaneously, the quaternary ammonium salt groups interact with high-valence cations in the matrix (such as Al3+, Fe...). 3+ The electrostatic interaction further strengthens the grain boundary bonding, reduces microscopic defects, and makes the material less prone to brittle fracture under dynamic loads.

[0059] Compared to Example 1, Comparative Example 1, without any modified titanium dioxide, exhibited lower flexural and compressive strengths and poorer crack resistance. Due to the lack of a reinforcing phase, the ceramic matrix contained numerous micropores and weak grain boundaries, allowing cracks to propagate almost linearly without hindrance under stress, leading to rapid material fracture. This structural defect manifested as extremely low compressive strength in bending or impact tests, clearly demonstrating that the unmodified ceramic matrix is ​​ill-suited to resist crack initiation and propagation, exhibiting severely inadequate crack resistance.

[0060] Comparative Example 2, with the direct addition of unmodified nano-titanium dioxide, exhibited a significantly lower compressive strength than Example 1. The unmodified nanoparticles, due to agglomeration, could not disperse uniformly, forming localized stress concentration points that became crack initiation points. During stress application, the weak interface between the agglomerates and the matrix preferentially cracked, accelerating crack propagation and resulting in limited improvement in compressive strength. This result demonstrates that simple nano-addition, without effective interface modification, not only fails to provide toughening but may also worsen the material's crack resistance.

[0061] Comparative Example 3 used carboxyl-terminated poly(dimethylaminoethyl methacrylate) to modify titanium dioxide, and Comparative Example 4 used stearic acid to modify titanium dioxide. Both showed lower flexural and compressive strengths than those of Example 1. This is because both lacked the electrostatic anchoring effect of quaternary ammonium salt groups, resulting in weak bonding between the modifier and the matrix, and easy crack propagation along the interface. This indicates that although carboxyl-terminated poly(dimethylaminoethyl methacrylate) can achieve a certain degree of modification through hydrogen bonding between the carboxyl groups and the hydroxyl groups on the surface of nano-titanium dioxide, the lack of quaternary ammonium salt cationic properties leads to weak electrostatic interaction with the ceramic matrix, resulting in insufficient interfacial bonding. Furthermore, the steric hindrance effect of the unquaternized polymer molecular chains is poor, making it difficult to effectively prevent nanoparticle aggregation, ultimately affecting the densification and mechanical property improvement of the material. This result further verifies the key role of quaternary ammonium salt groups in ceramic reinforcement modification.

[0062] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength, crack-resistant ceramic, characterized in that, The preparation method is as follows: Step S1: Add ethanol, deionized water, double-terminated carboxyl polyquaternary ammonium salt, and nano titanium dioxide to a flask, heat and stir, filter, wash with ethanol and deionized water, and dry to obtain polyquaternary ammonium salt modified titanium dioxide. Step S2: Mix quartz, clay, feldspar, alumina, talc, polyquaternium-modified titanium dioxide, polyvinyl alcohol, and deionized water, and then ball mill the mixture to obtain a slurry. Pour the slurry into a mold, dry it, press it into a green body, place it in a sintering furnace for sintering, and cool it to obtain a high-strength, crack-resistant ceramic.

2. The method for preparing high-strength, crack-resistant ceramics according to claim 1, characterized in that, In step S1, the ratio of double-ended carboxyl polyquaternary ammonium salt to nano-titanium dioxide is (8-20)g:100g.

3. The method for preparing high-strength, crack-resistant ceramics according to claim 1, characterized in that, In step S1, the heating temperature is 80-90℃, and the stirring time is 3 hours.

4. The method for preparing high-strength, crack-resistant ceramics according to claim 1, characterized in that, In step S2, the ratio of quartz, clay, feldspar, alumina, talc, polyquaternium-modified titanium dioxide, and polyvinyl alcohol is 100g:(75-90)g:(28-35)g:(3-8)g:(15-35)g:(1-8)g:(1.2-1.7)g.

5. The method for preparing high-strength, crack-resistant ceramics according to claim 1, characterized in that, In step S2, the ball milling time is 2-3 hours, and the ball milling speed is 500-800 r / min.

6. The method for preparing high-strength, crack-resistant ceramics according to claim 1, characterized in that, In step S2, the sintering process involves heating at a rate of 5-10℃ / min to 1200-1350℃ and holding the temperature for sintering for 3-5 hours.

7. The method for preparing high-strength, crack-resistant ceramics according to claim 2, characterized in that, The preparation method of the double-terminated carboxyl polyquaternary ammonium salt is as follows: (1) Add 1,4-dioxane, dimethylaminoethyl methacrylate, 2,2'-[thiocarbonyl(sulfur)]bis[2-methylpropionic acid], and 4,4'-azobis(4-cyanopentanoic acid) to a flask, stir, introduce nitrogen gas, heat to 85-100℃, reflux for 30-90 min, pour the solution into petroleum ether for precipitation, filter, wash with ethyl acetate, and dry to obtain carboxyl-terminated poly(dimethylaminoethyl methacrylate); (2) Add ethanol, dimethylaminoethyl methacrylate with carboxyl groups and bromoalkanes to a flask, heat to 70-80℃, stir and react for 18-24h, cool and filter, wash the precipitate with ethanol, dry and obtain dicarboxyl polyquaternary ammonium salt.

8. The method for preparing high-strength, crack-resistant ceramics according to claim 7, characterized in that, In (1), the ratio of dimethylaminoethyl methacrylate, 2,2'-[thiocarbonyl(sulfur)]bis[2-methylpropionic acid], and 4,4'-azobis(4-cyanopentanoic acid) is 100 mol:(0.1-0.13) mol:(0.03-0.05) mol.

9. The method for preparing high-strength, crack-resistant ceramics according to claim 7, characterized in that, In (2), the ratio of dimethylaminoethyl methacrylate with carboxyl groups at both ends to bromoalkane is 100g:(15-28)g.

10. The method for preparing high-strength, crack-resistant ceramics according to claim 9, characterized in that, The molecular formula of the bromoalkane in (2) is Br-C n H 2n+1 n is 2-4.

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