High-density ceramic coating and preparation method thereof

Abstract

The invention discloses a high-density ceramic coating and a preparation method thereof, and relates to the technical field of polymer coatings, the high-density ceramic coating comprises, by mass, 33-35 parts of silica sol, 43-45 parts of a solvent, 0.35-0.42 part of a weak acid buffer agent and 18.5-19.9 parts of an auxiliary agent; wherein the solvent is prepared from the following components in parts by mass: 25.5 to 26.5 parts of MTMS, 0.5 part of deionized water and 16 to 19 parts of ethanol; the silica sol comprises 25.5-26.5 parts by mass of 45nm SiO2 sol and the balance of 15-20nm SiO2 sol, and the SiO2 sol is modified silica sol which is loaded by a metal organic framework or is subjected to in-situ growth of graphene quantum dots. The wear-resistant and high-temperature-resistant valve has the effects of wear resistance, high temperature resistance and long service life.

Description

Technical Field

[0001] This application relates to the field of polymer coating technology, and in particular to a high-density ceramic coating and its preparation method. Background Technology

[0002] Ceramic coatings, as a novel type of coating that combines the advantages of both organic and inorganic substances through a reaction, are widely used in numerous fields. Traditional ceramic coatings are typically made by reacting inorganic polysiloxane compounds with organic acrylic resins and then curing them with a hardener. They possess many advantages, such as high hardness (new generation ceramic coatings can reach hardness above 6H); excellent high-temperature resistance, capable of withstanding temperatures up to 400℃; non-stick properties and a variety of colors; the ability to be formulated into water-based ceramic coatings; and excellent weather resistance, processability, dirt resistance, and damage resistance.

[0003] In coating systems, silica sol is often used as a key component. It can synergistically interact with silanes to form a composite structure, improving the coating's strength and toughness. In non-stick ceramic coatings such as cookware, silica sol can strengthen and densify the coating, enabling it to withstand high temperatures, reducing porosity, and improving abrasion resistance, scratch resistance, and corrosion resistance. Simultaneously, silica sol can also improve glaze stability, reduce cracks and defects, enhance glaze texture, gloss, and transparency, and increase the hardness and stain resistance of ceramic glazes.

[0004] Methyltrimethoxysilane (MTMS) is a commonly used siloxane monomer in the preparation of organic-inorganic composite ceramic coatings, possessing unique chemical properties. The methoxy group has an affinity for organic materials such as polymers and resins, while the silicon atoms readily bind to inorganic materials such as glass, metals, and ceramics. This dual-functionality allows MTMS to act as a coupling agent, forming strong chemical bonds between incompatible materials, thereby enhancing the adhesion between the coating and the substrate. This is crucial for creating robust composite materials and improving the performance and durability of adhesives and coatings.

[0005] However, in existing technologies, some ceramic coatings are prone to cracking when the coated parts are bent. This defect limits their application in some scenarios where high coating flexibility is required. Furthermore, one of the biggest drawbacks of existing ceramic coatings is their insufficient durability of non-stick properties. The non-stick properties of ceramic coatings mainly come from the methyl groups on the coating surface, currently primarily provided by silicone oil in the components. However, under high-temperature environments, or during cooking abrasion, and frequent cleaning with detergents, the number of methyl groups on the surface gradually decreases. Moreover, because the proportion of silicone oil added to ceramic coatings cannot be too high, otherwise, oil floating will occur, severely affecting the performance of the ceramic coating and significantly shortening its service life, which requires improvement. Summary of the Invention

[0006] In view of this, the first objective of this application is to provide a high-density ceramic coating to achieve wear resistance, high-temperature resistance, and long service life. The specific solution is as follows:

[0007] A high-density ceramic coating comprises 33-35 parts by weight of silica sol, 43-45 parts by weight of solvent, 0.35-0.42 parts by weight of weak acid buffer, and 18.5-19.9 parts by weight of additives; wherein:

[0008] The solvent comprises 25.5-26.5 parts by weight of MTMS, 0.5 parts by weight of deionized water, and 16-19 parts by weight of ethanol; the silica sol comprises 25.5-26.5 parts by weight of 45nm SiO2 sol and the balance being 15-20nm SiO2 sol, and the SiO2 sol is a modified silica sol supported by a metal-organic framework or grown in situ from graphene quantum dots.

[0009] Preferably, the weak acid buffer is glacial acetic acid.

[0010] Preferably, the additives include 6.5-7 parts by weight of TiO2, 3.2-3.6 parts by weight of CM-F3 ceramic powder, 2.8-3.2 parts by weight of CM-B silicon wafer powder, 0.6-0.8 parts by weight of Cu-Cr antibacterial agent, 2.5-2.9 parts by weight of nano-silica, 1.4-1.6 parts by weight of fused silica, 0.35-0.45 parts by weight of leveling agent, and 0.8-1 parts by weight of wear-resistant fines.

[0011] Preferably, the wear-resistant fine material is nano-silica with an average particle size of 10 nm.

[0012] Preferably, the metal-organic framework loading of the SiO2 sol includes step ① surface activation: adding 1.5-1.55 parts by weight of 3-aminopropyltriethoxysilane and 47-53 parts by weight of ethanol to 38-42 parts of silica sol, stirring at 48-52℃ for 3-3.5 hours, and then centrifuging and washing with ethanol to obtain the activated sol; step ② in-situ synthesis: dispersing the activated sol in DMF to form a sol solution with a solid content of 9-10%, then adding zinc nitrate and ultrasonically dispersing it evenly while controlling the zinc ion concentration to 0.09-0.12 mol / L, and finally... Add 2-methylimidazole and control the molar ratio of the added amount to zinc nitrate to 4:1. Stir the reaction at 30-32℃ for 20-28h. After washing and drying, obtain the loaded silica sol. Step ③: Functionalization: Disperse the loaded silica sol in 1-1.1g / L of ethyl perfluorooctanoate ethanol solution. Fill with ethyl perfluorooctanoate using a vacuum impregnation method with a vacuum degree of 0.05Pa, a temperature of 25℃, and a time of 8-10h. Control the solid-liquid ratio to 1:12-15. Dry at 35-42℃ for 4-5h to obtain a modified silica sol with a mass loading of 10-20%.

[0013] Preferably, in step ①, the centrifugation is performed at a speed of 7000-9000 r / min for 18-22 min; in step ②, the washing is performed by alternating washing with DMF and methanol 3-10 times, and the drying is performed by vacuum drying at 58-62℃ for 12-14 h.

[0014] Preferably, the in-situ growth of graphene quantum dots from SiO2 sol includes the following steps: Step ① Preparation: Take 5-5.2 parts by weight of citric acid and 2.9-3.1 parts by weight of urea and add 20-22 parts by weight of deionized water, stir until completely dissolved, and obtain GQDs precursor solution; Step ② In-situ growth: Mix the GQDs precursor solution with 38-42 parts by weight of silica sol ethanol solution, wherein the mass ratio of silica sol to ethanol in the silica sol ethanol solution is 3:1, react at a temperature of 180-182℃ for 8-10 hours, and control the heating rate at 5-6℃ / min to obtain the growth material; Step ③ Purification and optimization: Cool the growth material to room temperature, filter it through a filter membrane, and then sequentially undergo dialysis and stabilizer stirring treatment to obtain a modified silica sol with a mass growth rate of 1.2-2.8%.

[0015] Preferably, in step ③, the filter membrane is a 0.22-0.3 μm filter membrane; the dialysis treatment uses a dialysis bag and controls the molecular weight cutoff to be 800 Da or 1000 Da, and the dialysis time is 72-96 h; the stabilizer is 0.1-0.11 g / L of polyvinylpyrrolidone, and the stirring speed of the stirring treatment is controlled to be 300-400 r / min, and the stirring time is 30 min.

[0016] A second objective of this invention is to provide a method for preparing a high-density ceramic coating, comprising the following steps:

[0017] Step 1, Material preparation: Prepare 33-35 parts by weight of silica sol, 43-45 parts by weight of solvent, 0.35-0.42 parts by weight of weak acid buffer and 18.5-19.9 parts by weight of additives for later use;

[0018] Step 2, Basic Mixing: Take the solvent and add silica sol to it. After stirring evenly, add a weak acid buffer and adjust the pH to 4.0-4.5. Stir to obtain the silica sol-solvent system.

[0019] Step 3, Auxiliary agent dispersion: Add auxiliary agents to the silica sol-solvent system and stir to obtain a coarse mixture;

[0020] Step 4, Grinding and Control: Transfer the coarse mixture to a sand mill and grind it to obtain a grinding system with D50≤2μm, D90≤5μm and viscosity of 300-500mPa·s.

[0021] Step 5, Filtration and Packaging: The grinding system is treated with a filter membrane and sealed under inert gas protection.

[0022] Preferably, in step 3, the additives include TiO2, CM-F3 ceramic powder, CM-B silicon wafer powder, Cu-Cr antibacterial agent, nano-silica, fused silica, leveling agent, and wear-resistant fines; and the addition of additives includes first adding TiO2, CM-F3 ceramic powder, and CM-B silicon wafer powder, and increasing the speed of the disperser to 1200-1400 r / min and stirring for 12-15 min; then adding Cu-Cr antibacterial agent, maintaining the speed and stirring for 8-10 min, then adding nano-silica and fused silica, and reducing the speed to 900-1050 r / min and stirring for 12-15 min; finally adding leveling agent and wear-resistant fines, controlling the speed at 850-950 r / min and stirring for 7-10 min to form a coarse mixture system.

[0023] As can be seen from the above solutions, this application provides a high-density ceramic coating and its preparation method, which have the following beneficial effects:

[0024] 1. ZIF-8 nanoparticles in modified silica sol supported by metal-organic frameworks are covalently bonded to hydroxyl groups on the silica sol surface via APTES to form a core / shell structure. This porous structure stores a small amount of ethyl perfluorooctanoate during friction, achieving a micro-lubricating effect and reducing the coefficient of friction.

[0025] 2. In the modified silica sol by graphene quantum dots, the sheet structure of GQDs forms a sliding layer on the coating surface, thereby effectively reducing the interfacial shear force during friction. At the same time, GQDs and siloxane networks work together to improve the coating density, effectively reducing the problem of wear expansion caused by the intrusion of wear particles.

[0026] 3. The MTMS in the solvent generates a Si-O-Si cross-linked network structure after hydrolysis, which is not easily broken at high temperatures; and the MTMS forms an interpenetrating network structure with the SiO2 particles in the silica sol, which effectively inhibits the thermal expansion of the coating at high temperatures and reduces cracking caused by thermal stress.

[0027] 4. By loading ethyl perfluorooctanoate into the pores of ZIF-8, the pore confinement effect of ZIF-8 prevents the volatilization and loss of functional molecules at high temperatures; and the weak interaction between ethyl perfluorooctanoate and the siloxane network enhances the stability at high temperatures, ensuring that the coating maintains low surface energy after high-temperature use.

[0028] 5. By synergistically filling the internal pores of the coating with molten silica and nano-silica, a dense structure is formed, which effectively blocks the intrusion of corrosive media such as water, oxygen, and detergents, while reducing the hydrolysis and oxidation of the coating substrate. Detailed Implementation

[0029] The technical solutions described below in conjunction with the embodiments of this application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0030] It should be mentioned that the metal-organic framework used in this application embodiment is ZIF-8, which is formed by the self-assembly of zinc ions and 2-methylimidazolium coordination bonds, and will not be elaborated further here. Furthermore, the technical solution of this application achieves the preparation of a high-density ceramic coating by using a method for preparing a high-density ceramic coating according to an embodiment of this application.

[0031] The following will provide a detailed description of a high-density ceramic coating and its preparation method as described in this application.

[0032] A high-density ceramic coating comprises 33-35 parts by weight of silica sol, 43-45 parts by weight of solvent, 0.35-0.42 parts by weight of weak acid buffer, and 18.5-19.9 parts by weight of additives. In the embodiments of this application, the solvent comprises 25.5-26.5 parts by weight of MTMS, 0.5 parts by weight of deionized water, and 16-19 parts by weight of ethanol. The silica sol comprises 25.5-26.5 parts by weight of 45nm SiO2 sol and the balance being 15-20nm SiO2 sol, wherein the SiO2 sol is a modified silica sol supported on a metal-organic framework or grown in situ from graphene quantum dots. The weak acid buffer is glacial acetic acid.

[0033] It should be mentioned that the additives include 6.5-7 parts by weight of TiO2, 3.2-3.6 parts by weight of CM-F3 ceramic powder, 2.8-3.2 parts by weight of CM-B silicon wafer powder, 0.6-0.8 parts by weight of Cu-Cr antibacterial agent, 2.5-2.9 parts by weight of nano-silica, 1.4-1.6 parts by weight of fused silica, 0.35-0.45 parts by weight of leveling agent, and 0.8-1 parts by weight of wear-resistant fines. The wear-resistant fines are nano-silica with an average particle size of less than 12 nm.

[0034] It should be noted that the metal-organic framework loading of the SiO2 sol in this application embodiment includes step ① surface activation: adding 1.5-1.55 parts of 3-aminopropyltriethoxysilane and 50 parts of ethanol to 38-42 parts by weight of silica sol, stirring at 48-52℃ for 3-3.5 hours, and then centrifuging and washing with ethanol to obtain the activated sol; step ② in-situ synthesis: dispersing the activated sol in DMF to form a sol solution with a solid content of 9-10%, then adding zinc nitrate and ultrasonically dispersing it evenly while controlling the zinc ion concentration to 0.09-0.12 mol / L. Finally, 2-methylimidazole was added, and the molar ratio of the added amount to zinc nitrate was controlled at 4:1. The reaction was stirred at 30-32℃ for 20-28h. After washing and drying, the loaded silica sol was obtained. Step ③: Functionalization: The loaded silica sol was dispersed in a 1-1.1g / L ethyl perfluorooctanoate ethanol solution. Ethyl perfluorooctanoate was filled by vacuum impregnation at 0.05Pa, 25℃, and 8-10h, with the solid-liquid ratio controlled at 1:12-15. The solution was dried at 35-42℃ for 4-5h to obtain a modified silica sol with a mass loading of 10-20%.

[0035] In step ①, the centrifugation speed is controlled at 7000-9000 r / min for 18-22 min. In step ②, the washing is performed by alternating washing with DMF and methanol 3-10 times, and the drying is performed by vacuum drying at 58-62℃ for 12-14 h.

[0036] Meanwhile, the in-situ growth of graphene quantum dots from SiO2 sol includes the following steps: Step ① Preparation: Take 5-5.2 parts by weight of citric acid and 2.9-3.1 parts by weight of urea and add 20-22 parts by weight of deionized water, stir until completely dissolved, and obtain GQDs precursor solution; Step ② In-situ growth: Mix the GQDs precursor solution with 38-42 parts by weight of silica sol ethanol solution, with the mass ratio of silica sol to ethanol in the silica sol ethanol solution being 3:1, react at a temperature of 180-182℃ for 8-10 hours, and control the heating rate at 5-6℃ / min to obtain the growth material; Step ③ Purification and optimization: Cool the growth material to room temperature, filter it through a filter membrane, and then sequentially undergo dialysis and stabilizing stirring treatment to obtain modified silica sol with a mass growth rate of 1.2-2.8%.

[0037] In step ③, the filter membrane is a 0.22-0.3 μm membrane, and the dialysis treatment uses a dialysis bag with a molecular weight cutoff of 800 Da or 1000 Da, and the dialysis time is 72-96 h. The stabilizer is 0.1-0.11 g / L of polyvinylpyrrolidone, and the stirring speed is controlled at 300-400 r / min, and the stirring time is 30 min.

[0038] A method for preparing a high-density ceramic coating, comprising the following steps:

[0039] Step 1, Material preparation: Prepare 33-35 parts by weight of silica sol, 43-45 parts by weight of solvent, 0.35-0.42 parts by weight of weak acid buffer and 18.5-19.9 parts by weight of additives for later use;

[0040] Step 2, Basic Mixing: Take the solvent and add silica sol to it. After stirring evenly, add a weak acid buffer and adjust the pH to 4.0-4.5. Stir to obtain the silica sol-solvent system.

[0041] Step 3, Auxiliary Agent Dispersion: Add auxiliary agents to the silica sol-solvent system. These agents include TiO2, CM-F3 ceramic powder, CM-B silicon wafer powder, Cu-Cr antibacterial agent, nano-silica, fused silica, leveling agent, and wear-resistant fines. The addition of auxiliary agents involves first adding TiO2, CM-F3 ceramic powder, and CM-B silicon wafer powder, and then increasing the disperser speed to 1200-1400 r / min and stirring for 12-15 min. Next, add the Cu-Cr antibacterial agent, maintaining the stirring speed for 8-10 min, then add nano-silica and fused silica, and reduce the speed to 900-1050 r / min and stir for 12-15 min. Finally, add the leveling agent and wear-resistant fines, controlling the stirring speed at 850-950 r / min and stirring for 7-10 min to obtain a coarsely mixed system.

[0042] Step 4, Grinding and Control: Transfer the coarse mixture to a sand mill and grind it to obtain a grinding system with D50≤2μm, D90≤5μm and viscosity of 300-500mPa·s.

[0043] Step 5, Filtration and Packaging: The grinding system is treated with a filter membrane and sealed under inert gas protection.

[0044] Example 1

[0045] A high-density ceramic coating comprises 33 parts by weight of silica sol, 43 parts by weight of solvent, 0.35 parts by weight of glacial acetic acid, and 18.5 parts by weight of additives. In the embodiments of this application, the solvent comprises 25.5 parts by weight of MTMS, 0.5 parts by weight of deionized water, and 17 parts by weight of ethanol. The silica sol comprises 25.5 parts by weight of 45nm SiO2 sol and 7.5 parts by weight of 15nm SiO2 sol, and the SiO2 sol is supported on a metal-organic framework.

[0046] It should be mentioned that the additives include 6.5 parts by weight of TiO2, 3.2 parts of CM-F3 ceramic powder, 2.8 parts of CM-B silicon wafer powder, 0.6 parts of Cu-Cr antibacterial agent, 2.85 parts of nano-silica, 1.4 parts of fused silica, 0.35 parts of leveling agent, and 0.8 parts of wear-resistant fines. The wear-resistant fines are nano-silica with an average particle size of 10 nm.

[0047] It should be noted that the metal-organic framework loading of the SiO2 sol in this application embodiment includes step ① surface activation: adding 1.5 parts of 3-aminopropyltriethoxysilane and 50 parts of ethanol to 40 parts by weight of silica sol, stirring at 48°C for 3 hours, and then centrifuging and washing with ethanol to obtain the activated sol; step ② in-situ synthesis: dispersing the activated sol in DMF to form a sol solution with a solid content of 10%, then adding zinc nitrate and ultrasonically dispersing it evenly while controlling the zinc ion concentration to 0.1 mol / L. Finally, 2-methylimidazole was added and the molar ratio of the added amount to zinc nitrate was controlled at 4:1. The mixture was stirred at 30℃ for 20 h and then washed and dried to obtain the loaded silica sol. Step ③ Post-functionalization: The loaded silica sol was dispersed in a 1 g / L ethyl perfluorooctanoate ethanol solution. Ethyl perfluorooctanoate was filled using a vacuum impregnation method with a vacuum degree of 0.05 Pa, a temperature of 25℃, and a time of 8 h. The solid-liquid ratio was controlled at 1:12, and the mixture was dried at 35℃ for 4 h to obtain a modified silica sol with a mass loading of 10.63%.

[0048] In step ①, the centrifugation was performed at a speed of 7000 r / min for 20 min. In step ②, the washing was done by alternating washing with DMF and methanol three times, and the drying was performed under vacuum at 60℃ for 12 h.

[0049] A method for preparing a high-density ceramic coating, comprising the following steps:

[0050] Step 1, Material preparation: Prepare 33 parts by weight of silica sol, 43 parts by weight of solvent, 0.35 parts by weight of glacial acetic acid and 18.5 parts by weight of additives for later use;

[0051] Step 2, Basic Mixing: Take the solvent and add silica sol to it. After stirring evenly, add a weak acid buffer and adjust the pH to 4.0. Stir to obtain the silica sol-solvent system.

[0052] Step 3, Additive Dispersion: Additives are added to the silica sol-solvent system. These additives include TiO2, CM-F3 ceramic powder, CM-B silicon wafer powder, Cu-Cr antibacterial agent, nano-silica, fused silica, leveling agent, and wear-resistant fines. The addition process involves first adding TiO2, CM-F3 ceramic powder, and CM-B silicon wafer powder, and then increasing the disperser speed to 1200 rpm and stirring for 15 minutes. Next, the Cu-Cr antibacterial agent is added, and stirring is maintained at the same speed for 10 minutes. Then, nano-silica and fused silica are added, and the speed is reduced to 1000 rpm and stirred for 12 minutes. Finally, the leveling agent and wear-resistant fines are added, and stirring is maintained at 900 rpm for 8 minutes to obtain a coarse mixture.

[0053] Step 4, Grinding and Control: Transfer the coarse mixture to a sand mill and grind it to obtain a grinding system with D50≤2μm, D90≤5μm and viscosity of 300-500mPa·s.

[0054] Step 5, Filtration and Packaging: The grinding system is treated with a filter membrane and sealed under inert gas protection.

[0055] Example 2

[0056] A high-density ceramic coating comprises 34 parts by weight of silica sol, 44 parts by weight of solvent, 0.4 parts by weight of glacial acetic acid, and 19.3 parts by weight of additives. In the embodiments of this application, the solvent comprises 26 parts by weight of MTMS, 0.5 parts by weight of deionized water, and 17.5 parts by weight of ethanol. The silica sol comprises 26 parts by weight of 45nm SiO2 sol and 8 parts by weight of 15nm SiO2 sol, and the SiO2 sol is supported on a metal-organic framework.

[0057] It should be mentioned that the additives include 6.8 parts by weight of TiO2, 3.5 parts of CM-F3 ceramic powder, 3 parts of CM-B silicon wafer powder, 0.7 parts of Cu-Cr antibacterial agent, 2.5 parts of nano-silica, 1.5 parts of fused silica, 0.4 parts of leveling agent, and 0.9 parts of wear-resistant fines. The wear-resistant fines are nano-silica with an average particle size of 10 nm.

[0058] It should be noted that the metal-organic framework loading of the SiO2 sol in this application embodiment includes step ① surface activation: adding 1.5 parts of 3-aminopropyltriethoxysilane and 50 parts of ethanol to 40 parts by weight of silica sol, stirring at 50°C for 3 hours, and then centrifuging and washing with ethanol to obtain the activated sol; step ② in-situ synthesis: dispersing the activated sol in DMF to form a sol solution with a solid content of 10%, then adding zinc nitrate and ultrasonically dispersing it evenly while controlling the zinc ion concentration to 0.1 mol / L. 2-Methylimidazole was then added, and the molar ratio of the added amount to zinc nitrate was controlled at 4:1. The mixture was stirred at 30°C for 24 hours. After washing and drying, the loaded silica sol was obtained. Step ③: Functionalization: The loaded silica sol was dispersed in a 1 g / L ethyl perfluorooctanoate ethanol solution. Ethyl perfluorooctanoate was filled using a vacuum impregnation method with a vacuum degree of 0.05 Pa, a temperature of 25°C, and a time of 8 hours. The solid-liquid ratio was controlled at 1:14. The mixture was then dried at 40°C for 4.5 hours to obtain a modified silica sol with a mass loading of 16.71%.

[0059] In step ①, the centrifugation was performed at a speed of 8000 r / min for 20 min. In step ②, the washing was done by alternating washing with DMF and methanol three times, and the drying was performed under vacuum at 60℃ for 12 h.

[0060] A method for preparing a high-density ceramic coating, comprising the following steps:

[0061] Step 1, Material preparation: Prepare 34 parts by weight of silica sol, 44 parts by weight of solvent, 0.4 parts by weight of glacial acetic acid and 19.3 parts by weight of additives for later use;

[0062] Step 2, Basic Mixing: Take the solvent and add silica sol to it. After stirring evenly, add a weak acid buffer and adjust the pH to 4.2. Stir to obtain the silica sol-solvent system.

[0063] Step 3, Additive Dispersion: Additives are added to the silica sol-solvent system. These additives include TiO2, CM-F3 ceramic powder, CM-B silicon wafer powder, Cu-Cr antibacterial agent, nano-silica, fused silica, leveling agent, and wear-resistant fines. The addition process involves first adding TiO2, CM-F3 ceramic powder, and CM-B silicon wafer powder, and then increasing the disperser speed to 1200 rpm and stirring for 15 minutes. Next, the Cu-Cr antibacterial agent is added, and stirring is maintained at the same speed for 10 minutes. Then, nano-silica and fused silica are added, and the speed is reduced to 1000 rpm and stirred for 12 minutes. Finally, the leveling agent and wear-resistant fines are added, and stirring is maintained at 900 rpm for 8 minutes to obtain a coarse mixture.

[0064] Step 4, Grinding and Control: Transfer the coarse mixture to a sand mill and grind it to obtain a grinding system with D50≤2μm, D90≤5μm and viscosity of 300-500mPa·s.

[0065] Step 5, Filtration and Packaging: The grinding system is treated with a filter membrane and sealed under inert gas protection.

[0066] Example 3

[0067] A high-density ceramic coating comprises 35 parts by weight of silica sol, 45 parts by weight of solvent, 0.42 parts by weight of glacial acetic acid, and 19.9 parts by weight of additives. In the embodiments of this application, the solvent comprises 26.5 parts by weight of MTMS, 0.5 parts by weight of deionized water, and 18 parts by weight of ethanol. The silica sol comprises 26.5 parts by weight of 45nm SiO2 sol and 8.5 parts by weight of 20nm SiO2 sol, and the SiO2 sol is supported on a metal-organic framework.

[0068] It should be mentioned that the additives include 7 parts by weight of TiO2, 3.6 parts of CM-F3 ceramic powder, 2.95 parts of CM-B silicon wafer powder, 0.8 parts of Cu-Cr antibacterial agent, 2.5 parts of nano-silica, 1.6 parts of fused silica, 0.45 parts of leveling agent, and 1 part of wear-resistant fines. The wear-resistant fines are nano-silica with an average particle size of 10 nm.

[0069] It should be noted that the metal-organic framework loading of the SiO2 sol in this application embodiment includes step ① surface activation: adding 1.55 parts of 3-aminopropyltriethoxysilane and 50 parts of ethanol to 40 parts by weight of silica sol, stirring at 52°C for 3.5 h, and then centrifuging and washing with ethanol to obtain the activated sol; step ② in-situ synthesis: dispersing the activated sol in DMF to form a sol solution with a solid content of 10%, then adding zinc nitrate and ultrasonically dispersing it evenly while controlling the zinc ion concentration to 0.1 mol / L. L, finally add 2-methylimidazole and control the molar ratio of the added amount to zinc nitrate to 4:1. Stir the reaction at 32℃ for 28h. After washing and drying, the loaded silica sol is obtained. Step ③ Post-functionalization: The loaded silica sol is dispersed in 1g / L ethyl perfluorooctanoate ethanol solution. Based on the vacuum impregnation method of 0.05Pa-25℃-8h, ethyl perfluorooctanoate is filled, the solid-liquid ratio is controlled at 1:15, and the solution is dried at 38℃ for 5h to obtain a modified silica sol with a mass loading of 17.93%.

[0070] In step ①, the centrifugation was performed at a speed of 9000 r / min for 20 min. In step ②, the washing was done by alternating washing with DMF and methanol three times, and the drying was performed by vacuum drying at 60℃ for 12 h.

[0071] A method for preparing a high-density ceramic coating, comprising the following steps:

[0072] Step 1, Material preparation: Prepare 35 parts by weight of silica sol, 45 parts by weight of solvent, 0.42 parts by weight of glacial acetic acid and 19.9 parts by weight of additives for later use.

[0073] Step 2, Basic Mixing: Take the solvent and add silica sol to it. After stirring evenly, add a weak acid buffer and adjust the pH to 4.4. Stir to obtain the silica sol-solvent system.

[0074] Step 3, Additive Dispersion: Additives are added to the silica sol-solvent system. These additives include TiO2, CM-F3 ceramic powder, CM-B silicon wafer powder, Cu-Cr antibacterial agent, nano-silica, fused silica, leveling agent, and wear-resistant fines. The addition process involves first adding TiO2, CM-F3 ceramic powder, and CM-B silicon wafer powder, and then increasing the disperser speed to 1200 rpm and stirring for 15 minutes. Next, the Cu-Cr antibacterial agent is added, and stirring is maintained at the same speed for 10 minutes. Then, nano-silica and fused silica are added, and the speed is reduced to 1000 rpm and stirred for 12 minutes. Finally, the leveling agent and wear-resistant fines are added, and stirring is maintained at 900 rpm for 8 minutes to obtain a coarse mixture.

[0075] Step 4, Grinding and Control: Transfer the coarse mixture to a sand mill and grind it to obtain a grinding system with D50≤2μm, D90≤5μm and viscosity of 300-500mPa·s.

[0076] Step 5, Filtration and Packaging: The grinding system is treated with a filter membrane and sealed under inert gas protection.

[0077] Example 4

[0078] The difference between Example 4 and Example 2 is that the SiO2 sol in Example 4 is a modified silica sol grown in situ from graphene quantum dots.

[0079] The in-situ growth of graphene quantum dots (GQDs) from SiO2 sol includes the following steps: Step ① Preparation: Take 5 parts by weight of citric acid and 2.9 parts by weight of urea and add 20 parts by weight of deionized water, stir until completely dissolved, and obtain GQDs precursor solution; Step ② In-situ growth: Mix the GQDs precursor solution with 40 parts by weight of silica sol ethanol solution, with the mass ratio of silica sol to ethanol in the silica sol ethanol solution being 3:1, react at 180℃ for 8 hours, and control the heating rate at 5℃ / min to obtain the growth material; Step ③ Purification and optimization: Cool the growth material to room temperature, filter it through a filter membrane, and then sequentially undergo dialysis and stabilizer stirring treatment to obtain a modified silica sol with a mass growth rate of 1.92%.

[0080] In step ③, the filter membrane is a 0.22 μm membrane, and the dialysis treatment uses a dialysis bag with a molecular weight cutoff of 1000 Da, and the dialysis time is 72 h. The stabilizer is 0.1 g / L polyvinylpyrrolidone, and the stirring speed is controlled at 300 r / min, and the stirring time is 30 min.

[0081] Example 5

[0082] The difference between Example 5 and Example 4 is that the in-situ growth of graphene quantum dots from SiO2 sol in Example 5 includes the following steps: Step ① Backup composition: Take 5 parts by weight of citric acid and 3 parts by weight of urea and add 20 parts by weight of deionized water, stir until completely dissolved, and obtain GQDs precursor solution; Step ② In-situ growth: Mix the GQDs precursor solution with 40 parts by weight of silica sol ethanol solution, and the mass ratio of silica sol to ethanol in the silica sol ethanol solution is 3:1. React at 180℃ for 9 hours, and control the heating rate at 5℃ / min to obtain the growth material; Step ③ Purification and optimization: Cool the growth material to room temperature, filter it through a filter membrane, and then perform dialysis and stabilizer stirring treatment in sequence to obtain a modified silica sol with a mass growth rate of 2.17%.

[0083] In step ③, the filter membrane is a 0.22 μm membrane, and the dialysis treatment uses a dialysis bag with a molecular weight cutoff of 1000 Da, and the dialysis time is 72 h. The stabilizer is 0.1 g / L polyvinylpyrrolidone, and the stirring speed is controlled at 300 r / min, and the stirring time is 30 min.

[0084] Example 6

[0085] The difference between Example 6 and Example 4 is that the in-situ growth of graphene quantum dots from SiO2 sol in Example 6 includes the following steps: Step ① Backup composition: Take 5 parts by weight of citric acid and 3.1 parts by weight of urea and add 20 parts by weight of deionized water, stir until completely dissolved, and obtain GQDs precursor solution; Step ② In-situ growth: Mix the GQDs precursor solution with 40 parts by weight of silica sol ethanol solution, and the mass ratio of silica sol to ethanol in the silica sol ethanol solution is 3:1. React at 180℃ for 10 h, and control the heating rate at 5℃ / min to obtain the growth material; Step ③ Purification and optimization: Cool the growth material to room temperature, filter it through a filter membrane, and then perform dialysis and stabilizer stirring treatment in sequence to obtain a modified silica sol with a mass growth rate of 2.45%.

[0086] In step ③, the filter membrane is a 0.22 μm membrane, and the dialysis treatment uses a dialysis bag with a molecular weight cutoff of 1000 Da, and the dialysis time is 72 h. The stabilizer is 0.1 g / L polyvinylpyrrolidone, and the stirring speed is controlled at 300 r / min, and the stirring time is 30 min.

[0087] Example 7

[0088] The difference between Example 7 and Example 4 is that the SiO2 sol in Example 7 contains...

[0089] 45nm SiO2 sol was loaded with a metal-organic framework, and 15-20nm SiO2 sol was grown in situ using graphene quantum dots.

[0090] Comparative Example 1

[0091] The difference between Comparative Example 1 and Example 2 is that the SiO2 sol in Comparative Example 1 was not loaded with a metal-organic framework.

[0092] Comparative Example 2

[0093] The difference between Comparative Example 2 and Example 4 is that the SiO2 sol in Comparative Example 2 was not grown in situ with graphene quantum dots.

[0094] Performance testing:

[0095] Performance tests were conducted on the above embodiments and comparative examples as follows:

[0096] 1. Abrasion resistance test: Test the mass loss rate after 5000 friction cycles, according to GB / T 1768-2021 Determination of abrasion resistance of paints and varnishes;

[0097] 2. High temperature resistance test: The adhesion grade is tested at 700℃ for 2 hours, according to GB / T 1735-2009 Paints, Varnishes and Raw Materials for Paints and Varnishes;

[0098] 3. Service life test: The test measures the color change grade, adhesion and the mass loss rate after 3000 abrasion cycles after 3000 hours of accelerated aging, in accordance with GB / T 1865-2009 Paints and Varnishes Artificial weathering and artificial radiation exposure.

[0099] The performance test results are shown in Table 1 below.

[0100] Table 1 Performance Test Results

[0101] Abrasion resistance, % High temperature resistance Service life Example 1 0.86 Level 2 Color change: Level 3; Adhesion: Level 2; Loss rate: 1.20% Example 2 0.63 Level 1 Color change: Level 4; Adhesion: Level 1; Loss rate: 0.9% Example 3 0.59 Level 1 Color change: Level 4; Adhesion: Level 1; Loss rate: 0.85% Example 4 0.72 Level 2 Color change: Level 3; Adhesion: Level 2; Loss rate: 1% Example 5 0.66 Level 1 Color change: Level 4; Adhesion: Level 1; Loss rate: 0.95% Example 6 0.62 Level 1 Color change: Level 4; Adhesion: Level 1; Loss rate: 0.9% Example 7 0.56 Level 1 Color change: Level 4; Adhesion: Level 1; Loss rate: 0.85% Comparative Example 1 1.59 Level 4 Color change: Level 2; Adhesion: Level 4; Loss rate: 2.1% Comparative Example 2 1.40 Level 4 Color change: Level 2; Adhesion: Level 3; Loss rate: 1.95%

[0102] As shown in Table 1 above, in this embodiment, the modified silica sol, either supported by a metal-organic framework or grown in situ with graphene quantum dots, replaces the original sol, thereby significantly improving the wear resistance of the coating obtained from the high-density ceramic coating. Given the porous structure of the metal-organic framework, when loaded onto the surface of the SiO2 sol, it significantly increases the bonding force between particles within the coating, reducing particle shedding during friction by forming a dense network structure. Simultaneously, graphene quantum dots possess excellent mechanical properties; when grown in situ on the surface of the SiO2 sol, they form a strong morphological structure of nano-reinforcing phases within the coating, achieving the purpose of dispersing frictional stress and reducing coating wear. Furthermore, in Embodiment Seven of this application, it can be observed that the synergistic effect of composite modification—using 45nm SiO2 sol supported by a metal-organic framework and 20nm SiO2 sol grown in situ with graphene quantum dots—results in the coating exhibiting superior wear resistance, with a mass loss rate of only 0.56% after 5000 friction cycles.

[0103] As can be seen from Comparative Examples 1 and 2, since the SiO2 sol was not loaded with a metal-organic framework, the bonding force of the particles inside the coating is weak, resulting in more voids. This makes the particles easily detach during friction, leading to a mass loss rate of 1.59%. In contrast, the SiO2 sol in Comparative Example 2 was not grown in situ with graphene quantum dots, resulting in a lack of nano-reinforcing phase structure. This makes it difficult to effectively disperse frictional stress, resulting in poor wear resistance and a mass loss rate of 1.4%, which is much higher than the coating mass loss rate in the embodiments of this application.

[0104] Regarding high-temperature resistance, the SiO2 sol supported by the metal-organic framework undergoes partial decomposition at high temperatures. The resulting decomposition products synergistically interact with the SiO2 sol and other components to form a stable high-temperature resistant phase, effectively preventing the generation and diffusion of internal thermal stress in the coating, thus reducing cracking and peeling. Furthermore, when graphene quantum dots are grown in situ on the surface of the SiO2 sol, they rapidly conduct heat within the coating and effectively prevent localized high temperatures from causing coating damage, thereby maintaining the coating's structural integrity at high temperatures. Based on this, in Comparative Example 1, the SiO2 sol, lacking a metal-organic framework support, is prone to thermal stress concentration within the coating at high temperatures, leading to cracking and decreased adhesion, resulting in an adhesion grade of only 4 at 700℃. In Comparative Example 2, the SiO2 sol, without in-situ graphene quantum dot growth, suffers from insufficient thermal conductivity, causing localized high-temperature damage and reducing the adhesion grade to 3-4.

[0105] Regarding service life, since the SiO2 sol in Comparative Examples 1 and 2 was not modified, test data showed that the high-density ceramic coatings prepared through these comparative examples exhibited poor coating density and aging resistance. After 3000 hours of accelerated aging, the chemical bonds in the coating broke and the structure was damaged. Consequently, the discoloration grade decreased to level 2-3, the adhesion grade decreased to level 3-4, and the abrasion resistance decreased to 1.80%-2.00%, thus shortening the service life of Comparative Examples 1 and 2.

[0106] In summary, this application provides a high-density ceramic coating and its preparation method. This high-density ceramic coating and its preparation method utilize ZIF-8 nanoparticles in a modified silica sol supported by a metal-organic framework (GQD) to covalently bond with hydroxyl groups on the silica sol surface via APTES, forming a core / shell structure. This porous structure stores a small amount of ethyl perfluorooctanoate (PFOA) during friction, achieving a micro-lubrication effect and reducing the coefficient of friction. Specifically, in the graphene quantum dot (GQD) modified silica sol, a sliding layer is formed on the coating surface through the sheet structure of GQDs, effectively reducing the interfacial shear force during friction. Simultaneously, GQDs and the siloxane network synergistically enhance the coating density, effectively reducing the problem of wear amplification caused by the intrusion of wear particles. Furthermore, the MTMS in the solvent, after hydrolysis, generates a Si-O-Si cross-linked network structure that is not easily broken at high temperatures; and the MTMS forms an interpenetrating network structure with the SiO2 particles in the silica sol, effectively suppressing the thermal expansion of the coating at high temperatures and reducing cracking caused by thermal stress. To ensure that the coating obtained by this high-density ceramic coating maintains low surface energy after high-temperature use, ethyl perfluorooctanoate (PFOA) is loaded into the pores of ZIF-8. The pore confinement effect of ZIF-8 prevents the volatilization and loss of functional molecules at high temperatures, and enhances the stability at high temperatures through the weak interaction between PFOA and the siloxane network. Furthermore, when molten silica and nano-silica are synergistically filled into the pores of the coating to form a dense structure, it effectively blocks the intrusion of corrosive media such as water, oxygen, and detergents, while reducing the hydrolysis and oxidation of the coating substrate.

[0107] The terms “first,” “second,” “third,” “fourth,” etc., used in this application (if applicable) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, or apparatus that includes a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, or apparatus.

[0108] It should be noted that the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0109] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A high-density ceramic coating, characterized in that: It includes 33-35 parts by weight of silica sol, 43-45 parts by weight of solvent, 0.35-0.42 parts by weight of weak acid buffer, and 18.5-19.9 parts by weight of additives; wherein: The solvent comprises 25.5-26.5 parts by weight of MTMS, 0.5 parts by weight of deionized water, and 16-19 parts by weight of ethanol; the silica sol comprises 25.5-26.5 parts by weight of 45nm SiO2 sol and the balance being 15-20nm SiO2 sol, and the SiO2 sol is a modified silica sol supported by a metal-organic framework or grown in situ from graphene quantum dots.

2. The high-density ceramic coating according to claim 1, characterized in that: The weak acid buffer is glacial acetic acid.

3. The high-density ceramic coating according to claim 1, characterized in that: The additives include, by weight, 6.5-7 parts TiO2, 3.2-3.6 parts CM-F3 ceramic powder, 2.8-3.2 parts CM-B silicon wafer powder, 0.6-0.8 parts Cu-Cr antibacterial agent, 2.5-2.9 parts nano silica, 1.4-1.6 parts fused silica, 0.35-0.45 parts leveling agent, and 0.8-1 parts wear-resistant fines.

4. The high-density ceramic coating according to claim 3, characterized in that: The wear-resistant fine material is nano-silica with an average particle size of less than 12 nm.

5. The high-density ceramic coating according to claim 1, characterized in that: The metal-organic framework loading of the SiO2 sol includes the following steps: Step ① Surface activation: 1.5-1.55 parts by weight of 3-aminopropyltriethoxysilane and 47-53 parts by weight of ethanol are added to 38-42 parts by weight of silica sol, and the mixture is stirred at 48-52℃ for 3-3.5 hours. The sol is then obtained by centrifugation and washing with ethanol. Step ② In-situ synthesis: The activated sol is dispersed in DMF to form a sol solution with a solid content of 9-10%. Zinc nitrate is then added and ultrasonically dispersed to ensure uniform dispersion, with the zinc ion concentration controlled at 0.09-0.12 mol / L. Finally, [the text abruptly ends here]. 2-Methylimidazole was added at a molar ratio of 4:1 to zinc nitrate, and the mixture was stirred at 30-32℃ for 20-28 hours. After washing and drying, the loaded silica sol was obtained. Step ③: Functionalization: The loaded silica sol was dispersed in a 1-1.1 g / L ethyl perfluorooctanoate ethanol solution. Ethyl perfluorooctanoate was filled using a vacuum impregnation method with a vacuum degree of 0.05 Pa, a temperature of 25℃, and a time of 8-10 hours. The solid-liquid ratio was controlled at 1:12-15, and the mixture was dried at 35-42℃ for 4-5 hours to obtain a modified silica sol with a mass loading of 10-20%.

6. The high-density ceramic coating according to claim 5, characterized in that: In step ①, the centrifugation is performed at a speed of 7000-9000 r / min for 18-22 min; in step ②, the washing is performed by alternating washing with DMF and methanol 3-10 times, and the drying is performed by vacuum drying at 58-62℃ for 12-14 h.

7. The high-density ceramic coating according to claim 1, characterized in that: The in-situ growth of graphene quantum dots from SiO2 sol includes the following steps: Step ① Preparation: Take 5-5.2 parts by weight of citric acid and 2.9-3.1 parts by weight of urea and add 20-22 parts by weight of deionized water, stir until completely dissolved, and obtain GQDs precursor solution; Step ② In-situ growth: Mix the GQDs precursor solution with 38-42 parts by weight of silica sol ethanol solution, with the mass ratio of silica sol to ethanol in the silica sol ethanol solution being 3:1, react at a temperature of 180-182℃ for 8-10 hours, and control the heating rate at 5-6℃ / min to obtain the growth material; Step ③ Purification and optimization: Cool the growth material to room temperature, filter it through a filter membrane, and then sequentially undergo dialysis and stabilizing stirring treatment to obtain a modified silica sol with a mass growth rate of 1.2-2.8%.

8. The high-density ceramic coating according to claim 7, characterized in that: In step ③, the filter membrane is a 0.22-0.3 μm filter membrane; the dialysis treatment uses a dialysis bag and controls the molecular weight cutoff to be 800 Da or 1000 Da, and the dialysis time is 72-96 h; the stabilizer is 0.1-0.11 g / L of polyvinylpyrrolidone, and the stirring speed of the stirring treatment is controlled to be 300-400 r / min, and the stirring time is 30 min.

9. A method for preparing a high-density ceramic coating, used to prepare a high-density ceramic coating as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1, Material preparation: Prepare 33-35 parts by weight of silica sol, 43-45 parts by weight of solvent, 0.35-0.42 parts by weight of weak acid buffer and 18.5-19.9 parts by weight of additives for later use; Step 2, Basic Mixing: Take the solvent and add silica sol to it. After stirring evenly, add a weak acid buffer and adjust the pH to 4.0-4.

5. Stir to obtain the silica sol-solvent system. Step 3, Auxiliary agent dispersion: Add auxiliary agents to the silica sol-solvent system and stir to obtain a coarse mixture; Step 4, Grinding and Control: Transfer the coarse mixture to a sand mill and grind it to obtain a grinding system with D50≤2μm, D90≤5μm and viscosity of 300-500mPa·s. Step 5, Filtration and Packaging: The grinding system is treated with a filter membrane and sealed under inert gas protection.

10. The method for preparing a high-density ceramic coating according to claim 9, characterized in that: In step 3, the additives include TiO2, CM-F3 ceramic powder, CM-B silicon wafer powder, Cu-Cr antibacterial agent, nano-silica, fused silica, leveling agent, and wear-resistant fines. The addition of additives includes first adding TiO2, CM-F3 ceramic powder, and CM-B silicon wafer powder, and increasing the speed of the disperser to 1200-1400 r / min and stirring for 12-15 min; then adding Cu-Cr antibacterial agent, maintaining the speed and stirring for 8-10 min, then adding nano-silica and fused silica, and reducing the speed to 900-1050 r / min and stirring for 12-15 min; finally adding leveling agent and wear-resistant fines, controlling the speed at 850-950 r / min and stirring for 7-10 min to form a coarse mixture system.