A high density ceramic coating and method of making the same

Abstract

The application discloses a high-density ceramic coating and a preparation method thereof, relates to the technical field of high polymer coatings, and comprises 33-35 parts of silica sol, 43-45 parts of a solvent, 0.35-0.42 parts of a weak acid buffer and 18.5-19.9 parts of an additive by mass fraction; wherein the solvent comprises 25.5-26.5 parts of MTMS, 0.5 parts of deionized water and 16-19 parts of ethanol by mass fraction; the silica sol comprises 25.5-26.5 parts of 45nm SiO2 sol and 15-20nm SiO2 sol as the balance, and the SiO2 sol is modified silica sol loaded with a metal organic framework or in-situ grown with graphene quantum dots. The application has the effect of realizing wear resistance, high-temperature resistance and long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer coating, in particular to a high-density ceramic coating and a preparation method thereof. BACKGROUND

[0002] As a novel coating that can react organic matter with inorganic matter and has the advantages of both, ceramic coating is widely used in many fields. Traditional ceramic coating is usually made by reacting inorganic polysiloxane compounds with organic acrylic resins and curing through a hardener. It has many advantages, such as high hardness, the hardness of the new generation of ceramic coating can reach more than 6H; good high-temperature resistance, can withstand 400℃ high temperature; has non-stick effect and various colors, can also be made into water-based ceramic coating, has excellent weather resistance and processing performance, is resistant to dirt and damage.

[0003] In the coating system, silica sol is often used as a key ingredient, which can work together with silane to form a composite structure, improving the firmness and toughness of the coating. In the application of non-stick ceramic coating on cookware, silica sol can enhance and densify the coating, making it able to withstand high temperatures, reduce porosity, and improve wear resistance, scratch resistance, and corrosion resistance. At the same time, silica sol can also improve the stability of glaze, reduce cracks and defects, improve the texture, gloss and transparency of the glaze surface, and enhance the hardness and stain resistance of ceramic glaze.

[0004] Methyltrimethoxysilane, MTMS, is a commonly used siloxane monomer for preparing organic-inorganic composite ceramic coatings. It has unique chemical properties. The methoxy group has affinity for organic materials such as polymers and resins, and the silicon atom is easily combined with inorganic materials such as glass, metal and ceramic. This dual functional property enables MTMS to act as a coupling agent, forming strong chemical bonds between incompatible materials, thereby enhancing the adhesion between the coating and the substrate, which is crucial for creating strong composite materials and improving the performance and durability of adhesives and coatings.

[0005] However, in the prior art, some ceramic coatings are prone to cracking when the coated parts are bent. In some applications where the flexibility of the coating is required, this defect limits its use. In addition, one of the biggest drawbacks of existing ceramic coatings is that the non-stick performance is not durable enough. The non-stickiness of ceramic coating mainly comes from the methyl groups on the surface of the coating. Currently, the methyl groups are mainly provided by the silicone oil in the components. However, in high-temperature environments, or during cooking, the number of methyl groups on the surface will gradually decrease. And because the proportion of silicone oil in ceramic coating cannot be too high, otherwise it will seriously affect the performance of ceramic coating due to the appearance of floating oil, which significantly shortens the service life of ceramic coating, and needs to be improved. SUMMARY

[0006] Therefore, the first object of the present application is to provide a high-density ceramic coating to achieve the purposes of wear resistance, high temperature resistance and long service life. The specific scheme is as follows:

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

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

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

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

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

[0012] Preferably, the metal organic framework loading of the SiO2 sol comprises the following steps: step ① surface activation: adding 1.5-1.55 parts of 3-aminopropyl triethoxysilane and 47-53 parts of ethanol to 38-42 parts of silica sol by weight, controlling the temperature to 48-52℃, stirring for 3-3.5 h, and obtaining an activated sol after centrifugation and ethanol washing; 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 uniformly dispersing under ultrasonic, controlling the zinc ion concentration to be 0.09-0.12 mol / L, finally adding 2-methyl imidazole and controlling the molar ratio of the amount of 2-methyl imidazole to zinc nitrate to be 4:1, stirring for 20-28 h at a temperature of 30-32℃, and obtaining a loaded silica sol after washing and drying; step ③ post-functionalization: dispersing the loaded silica sol in 1-1.1 g / L of a perfluorooctanoic acid ethyl ester ethanol solution, filling perfluorooctanoic acid ethyl ester by vacuum impregnation with a vacuum degree of 0.05 Pa, a temperature of 25℃, and a time of 8-10 h, controlling the solid-liquid ratio to be 1:12-15, and drying at a temperature of 35-42℃ for 4-5 h to obtain a modified silica sol with a mass loading of 10-20%.

[0013] Preferably, in step ①, the centrifugation is controlled at a rotation speed of 7000-9000 r / min for 18-22 min; in step ②, the washing is performed by alternating washing with DMF and methanol for 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 of the SiO2 sol comprises the following steps: step ① backup composition: taking 5-5.2 parts of citric acid and 2.9-3.1 parts of urea by weight, and adding 20-22 parts of deionized water, stirring until completely dissolved, and obtaining a GQDs precursor solution; step ② in-situ growth: mixing the GQDs precursor solution with 38-42 parts of a silica sol ethanol solution, and controlling the mass ratio of the silica sol to ethanol in the silica sol ethanol solution to be 3:1, reacting at a temperature of 180-182℃ for 8-10 h, and controlling the heating rate to be 5-6℃ / min to obtain a growth material; step ③ purification optimization: cooling the growth material to room temperature, filtering through a filter membrane, and then sequentially performing dialysis treatment 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 is performed using a dialysis bag with a molecular weight cut-off of 800 Da or 1000 Da, and the dialysis time is 72-96 h; and the stabilizer is 0.1-0.11 g / L of polyvinylpyrrolidone, and the stirring speed for stirring treatment is controlled to be 300-400 r / min, and the stirring time is 30 min.

[0016] A second object of the present application is to provide a preparation method of high-density ceramic paint for preparing a high-density ceramic paint as described above, comprising the following steps:

[0017] Step 1, material preparation: 33-35 parts by mass of silica sol, 43-45 parts by mass of solvent, 0.35-0.42 parts by mass of weak acid buffer, and 18.5-19.9 parts by mass of additives are prepared for use;

[0018] Step 2, base mixing: take the solvent and add silica sol to the solvent, after stirring uniformly, add weak acid buffer and adjust the pH to 4.0-4.5, and stir to obtain a silica sol-solvent system;

[0019] Step 3, additive dispersion: add additives to the silica sol-solvent system, and stir to obtain a coarse mixing system;

[0020] Step 4, grinding control: transfer the coarse mixing system to a sand mill, and after grinding treatment, obtain a grinding system with D50≤2μm, D90≤5μm and viscosity of 300-500mPa·s;

[0021] Step 5, filtration and packaging: filter the grinding system with filter membrane, and seal and package under inert gas protection.

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

[0023] From the above scheme, it can be seen that the present application provides a high-density ceramic paint and a preparation method thereof, which has the following beneficial effects:

[0024] 1. The ZIF-8 nanoparticles in the modified silica sol loaded by metal-organic framework are covalently combined with the surface hydroxyl groups of the silica sol through APTES, forming a core / shell structure, so that the porous structure formed thereby stores a small amount of perfluorooctanoic acid ethyl ester during friction, achieving the effects of micro-lubrication and reducing the friction coefficient;

[0025] 2、through the modified silicon sol of graphene quantum dots, the sheet structure of GQDs forms a sliding layer on the surface of the coating, thereby effectively reducing the interface shear force during friction, and at the same time, GQDs and the siloxane network synergistically improve the density of the coating, effectively reducing the problem of wear expansion caused by the invasion of wear particles;

[0026] 3、through the cross-linked network structure of Si-O-Si generated by MTMS in the solvent after hydrolysis, which is not easy to break at high temperature; and the interpenetrating network structure formed by MTMS and SiO2 particles in the silica sol effectively inhibits the thermal expansion of the coating at high temperature and reduces the cracking caused by thermal stress;

[0027] 4、through the perfluorooctanoic acid ethyl ester loaded in the channel of ZIF-8, the channel restriction of ZIF-8 prevents the volatilization loss of functional molecules at high temperature; and the weak interaction between perfluorooctanoic acid ethyl ester and the siloxane network enhances the stability at high temperature, ensuring that the coating still maintains low surface energy after high-temperature use;

[0028] 5、through the synergistic filling of fused silica and nanosilica in the pores inside the coating, a dense structure is formed, which effectively blocks the invasion of corrosion media such as water, oxygen and detergents, while reducing the hydrolysis and oxidation of the coating matrix. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0030] It should be noted that the metal organic framework in the embodiments of the present application is ZIF-8, which is formed by self-assembly of zinc ions and 2-methyl imidazole coordination bonds, which will not be described here. The high-density ceramic coating obtained by the preparation method of the high-density ceramic coating in the embodiments of the present application is used to prepare the coating.

[0031] The high-density ceramic coating and its preparation method of the present application will be described in detail below.

[0032] A high-density ceramic coating includes 33-35 parts by mass of silica sol, 43-45 parts by mass of solvent, 0.35-0.42 parts by mass of weak acid buffer, and 18.5-19.9 parts by mass of auxiliary agent. In the embodiments of the present application, the solvent includes 25.5-26.5 parts by mass of MTMS, 0.5 parts by mass of deionized water, and 16-19 parts by mass of ethanol. The silica sol includes 25.5-26.5 parts by mass of 45 nm SiO2 sol and 15-20 nm SiO2 sol as the balance, and the SiO2 sol is a modified silica sol loaded with metal organic frameworks or in-situ grown with graphene quantum dots. The weak acid buffer is glacial acetic acid.

[0033] It should be noted that the auxiliary agent includes 6.5-7 parts by mass of TiO2, 3.2-3.6 parts by mass of CM-F3 ceramic powder, 2.8-3.2 parts by mass of CM-B silicon flake powder, 0.6-0.8 parts by mass of Cu-Cr antibacterial agent, 2.5-2.9 parts by mass of nano-silica, 1.4-1.6 parts by mass of fused silica, 0.35-0.45 parts by mass of leveling agent, and 0.8-1 parts by mass 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 the embodiments of the present application includes the following steps: ① surface activation: adding 1.5-1.55 parts by mass of 3-aminopropyltriethoxysilane and 50 parts by mass of ethanol to 38-42 parts by mass of silica sol, controlling the temperature to 48-52°C, stirring for 3-3.5 hours, and then obtaining an activated sol after centrifugation and ethanol washing; 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 uniformly dispersing under ultrasonic, controlling the zinc ion concentration to be 0.09-0.12 mol / L, finally adding 2-methyl imidazole and controlling the molar ratio of the addition amount to zinc nitrate to be 4:1, stirring for 20-28 hours at a temperature of 30-32°C, and then obtaining a loaded silica sol after washing and drying; and ③ post-functionalization: dispersing the loaded silica sol in 1-1.1 g / L of perfluorooctanoic acid ethyl ester ethanol solution, filling perfluorooctanoic acid ethyl ester based on a vacuum impregnation method with a vacuum degree of 0.05 Pa, a temperature of 25°C, and a time of 8-10 hours, controlling the solid-liquid ratio to be 1:12-15, and drying at a temperature of 35-42°C for 4-5 hours to obtain a modified silica sol with a mass loading of 10-20%.

[0035] In step ①, the centrifugation is controlled at a speed of 7000-9000 r / min for 18-22 min. In step ②, the washing is performed 3-10 times alternately with DMF and methanol, and the drying is performed at 58-62°C for 12-14 hours under vacuum.

[0036] Meanwhile, the graphene quantum dots in-situ growth of SiO2 sol includes steps ① backup composition: taking 5-5.2 parts of citric acid and 2.9-3.1 parts of urea by weight, and adding 20-22 parts of deionized water, stirring until completely dissolved and obtaining GQDs precursor solution; step ② in-situ growth: mixing the GQDs precursor solution with 38-42 parts of silica sol ethanol solution, and the mass ratio of silica sol and ethanol in the silica sol ethanol solution is 3:1, reacting at a temperature of 180-182℃ for 8-10h, controlling the heating rate to be 5-6℃ / min, obtaining the growth material; step ③ purification optimization: cooling the growth material to room temperature, filtering through a filter membrane, and then sequentially treating with dialysis and stirring with a stabilizer, obtaining modified silica sol with a mass growth rate of 1.2-2.8%.

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

[0038] A preparation method of a high-density ceramic coating, for preparing a high-density ceramic coating as described above, comprising the following steps:

[0039] Step 1, material preparation: preparing 33-35 parts of silica sol, 43-45 parts of solvent, 0.35-0.42 parts of weak acid buffer, and 18.5-19.9 parts of additives by mass fraction for standby;

[0040] Step 2, basic mixing: taking the solvent and adding silica sol into the solvent, stirring uniformly, then adding a weak acid buffer and adjusting the pH to 4.0-4.5, and stirring to obtain a silica sol-solvent system;

[0041] Step 3, additive dispersion: adding additives into the silica sol-solvent system, the additives including TiO2, CM-F3 ceramic powder, CM-B silicon flake powder, Cu-Cr antibacterial agent, nano-silicon dioxide, fused silica, leveling agent, and wear-resistant material; and the adding of the additives includes first adding TiO2, CM-F3 ceramic powder, and CM-B silicon flake powder, and increasing the rotation speed of the dispersing machine to 1200-1400r / min for stirring for 12-15min; then adding Cu-Cr antibacterial agent, maintaining the rotation speed for stirring for 8-10min, and then adding nano-silicon dioxide and fused silica, and reducing the rotation speed to 900-1050r / min for stirring for 12-15min; finally, adding leveling agent and wear-resistant material, controlling the rotation speed to be 850-950r / min for stirring for 7-10min, and obtaining a coarse mixing system;

[0042] Step 4, grinding regulation: the crude mixture is transferred to a sand mill, and a grinding system with D50≤2 μm, D90≤5 μm and viscosity of 300-500 mPa·s is obtained after grinding treatment;

[0043] Step 5, filtration and packaging: the grinding system is filtered by using a filter membrane, and is sealed and packaged under the protection of inert gas.

[0044] Example 1

[0045] A high-density ceramic coating includes 33 parts by mass of silica sol, 43 parts by mass of solvent, 0.35 parts by mass of glacial acetic acid, and 18.5 parts by mass of additives. In the example of the present application, the solvent includes 25.5 parts by mass of MTMS, 0.5 parts by mass of deionized water, and 17 parts by mass of ethanol. The silica sol includes 25.5 parts by mass of 45 nm SiO2 sol and 7.5 parts by mass of 15 nm SiO2 sol, and the SiO2 sol is loaded with metal organic frameworks.

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

[0047] It should be noted that the metal organic framework loading of the SiO2 sol in the example of the present application includes step ① surface activation: 1.5 parts by mass of 3-aminopropyl triethoxysilane and 50 parts by mass of ethanol are added to 40 parts by mass of silica sol, the temperature is controlled at 48°C, and the stirring reaction is carried out for 3h, and then the activated sol is obtained after centrifugation and ethanol washing; step ② in-situ synthesis: the activated sol is dispersed in DMF to form a sol solution with a solid content of 10%, then zinc nitrate is added and ultrasonically dispersed uniformly, and the zinc ion concentration is controlled at 0.1 mol / L, finally 2-methyl imidazole is added and the molar ratio of the addition amount to zinc nitrate is controlled at 4:1, the stirring reaction is carried out for 20h at a temperature of 30°C, and then the loaded silica sol is obtained after washing and drying; step ③ post-functionalization: the loaded silica sol is dispersed in 1g / L of perfluorooctanoic acid ethyl ester ethanol solution, perfluorooctanoic acid ethyl ester is filled by vacuum impregnation method with a vacuum degree of 0.05 Pa, a temperature of 25°C and a time of 8h, the solid-liquid ratio is controlled at 1:12, and the modified silica sol with a mass loading of 10.63% is obtained after drying treatment at a temperature of 35°C for 4h.

[0048] The centrifugation in step 1 is controlled at 7000 r / min for 20 min. The washing in step 2 is performed by using DMF and methanol for 3 times, and the drying is performed at 60℃ for 12 h under vacuum.

[0049] A preparation method of a high-density ceramic coating, for preparing a high-density ceramic coating as described above, comprising the following steps:

[0050] Step 1, material preparation: 33 parts of silica sol, 43 parts of solvent, 0.35 parts of glacial acetic acid and 18.5 parts of additives are prepared for use;

[0051] Step 2, base mixing: the solvent is taken and the silica sol is added into the solvent, after stirring uniformly, the weak acid buffer is added and the pH is adjusted to 4.0, and the silica sol-solvent system is obtained by stirring;

[0052] Step 3, additive dispersion: the additives are added into the silica sol-solvent system, the additives include TiO2, CM-F3 ceramic powder, CM-B silicon flake powder, Cu-Cr antibacterial agent, nano-silicon dioxide, fused silica, leveling agent and wear-resistant material; and the additives are added in the following order: TiO2, CM-F3 ceramic powder and CM-B silicon flake powder, and the disperser speed is increased to 1200 r / min for stirring for 15 min; then the Cu-Cr antibacterial agent is added, and after stirring for 10 min at the same speed, the nano-silicon dioxide and the fused silica are added, and the speed is reduced to 1000 r / min for stirring for 12 min; finally, the leveling agent and the wear-resistant material are added, and the speed is controlled at 900 r / min for stirring for 8 min, to obtain a coarse mixing system;

[0053] Step 4, grinding control: the coarse mixing system is transferred to a sand mill, and after grinding treatment, a grinding system with D50≤2 μm, D90≤5 μm and viscosity of 300-500 mPa·s is obtained;

[0054] Step 5, filtration and packaging: the grinding system is filtered by using a filter membrane, and is sealed and packaged under the protection of inert gas.

[0055] Example 2

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

[0057] It needs to be mentioned that the auxiliary agent includes 6.8 parts of TiO2, 3.5 parts of CM-F3 ceramic powder, 3 parts of CM-B silicon flake powder, 0.7 parts of Cu-Cr antibacterial agent, 2.5 parts of nano-silicon dioxide, 1.5 parts of fused silica, 0.4 parts of leveling agent, and 0.9 parts of wear-resistant fines. And the wear-resistant fines are nano-silicon dioxide with an average particle size of 10 nm.

[0058] It needs to be explained that the metal organic framework loading of the SiO2 sol in the embodiment of the application includes the following steps: ① surface activation: 1.5 parts of 3-aminopropyl triethoxysilane and 50 parts of ethanol are added to 40 parts of silica sol by weight, the temperature is controlled at 50°C, and the activated sol is obtained after stirring for 3h and sequentially centrifuging and washing with ethanol; ② in-situ synthesis: the activated sol is dispersed in DMF to form a sol solution with a solid content of 10%, zinc nitrate is then added and uniformly dispersed by ultrasonic, and the zinc ion concentration is controlled at 0.1 mol / L, finally 2-methyl imidazole is added and the molar ratio of the addition amount to zinc nitrate is controlled at 4:1, the modified silica sol with a mass loading of 16.71% is obtained after stirring for 24h at a temperature of 30°C, sequentially washing and drying; ③ post-functionalization: the loaded silica sol is dispersed in 1g / L of a perfluorooctanoic acid ethyl ester ethanol solution, perfluorooctanoic acid ethyl ester is filled by a vacuum impregnation method with a vacuum degree of 0.05 Pa, a temperature of 25°C and a time of 8h, the solid-liquid ratio is controlled at 1:14, and the modified silica sol is obtained after drying treatment at a temperature of 40°C for 4.5h.

[0059] In step ①, the centrifugation is controlled at a speed of 8000r / min for 20min. In step ②, the washing is performed by using DMF and methanol alternately for 3 times, and the drying is performed by vacuum drying at 60°C for 12h.

[0060] A preparation method of a high-density ceramic coating, for preparing a high-density ceramic coating as described above, comprising the following steps:

[0061] Step 1, material preparation: 34 parts of silica sol, 44 parts of solvent, 0.4 parts of glacial acetic acid and 19.3 parts of auxiliary agent are prepared by mass fraction;

[0062] Step 2, basic mixing: the solvent is taken and the silica sol is added to the solvent, after stirring uniformly, the weak acid buffer is added and the pH is adjusted to 4.2, and the silica sol-solvent system is obtained by stirring;

[0063] Step 3, dispersing the additives: adding the additives into the silica sol-solvent system, the additives including TiO2, CM-F3 ceramic powder, CM-B silicon flake powder, Cu-Cr antibacterial agent, nano-silica, fused silica, leveling agent and wear-resistant fines; and the adding of the additives includes adding TiO2, CM-F3 ceramic powder and CM-B silicon flake powder first, and increasing the rotation speed of the dispersing machine to 1200 r / min and stirring for 15 min; then adding the Cu-Cr antibacterial agent, maintaining the rotation speed and stirring for 10 min, and then adding the nano-silica and fused silica, and reducing the rotation speed to 1000 r / min and stirring for 12 min; finally, adding the leveling agent and wear-resistant fines, controlling the rotation speed to 900 r / min and stirring for 8 min, to obtain a coarse mixed system;

[0064] Step 4, grinding regulation: transferring the coarse mixed system into a sand mill, and obtaining a ground system with D50≤2 μm, D90≤5 μm and viscosity of 300-500 mPa·s after grinding treatment;

[0065] Step 5, filtering and packaging: filtering the ground system by using a filter membrane, and sealing and packaging under the protection of inert gas.

[0066] Example Three

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

[0068] It should be noted that the additives include 7 parts by mass of TiO2, 3.6 parts by mass of CM-F3 ceramic powder, 2.95 parts by mass of CM-B silicon flake powder, 0.8 parts by mass of Cu-Cr antibacterial agent, 2.5 parts by mass of nano-silica, 1.6 parts by mass of fused silica, 0.45 parts by mass of leveling agent and 1 part by mass 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 the embodiments of the present application includes the following steps: ① surface activation: 1.55 parts of 3-aminopropyl triethoxysilane and 50 parts of ethanol are added to 40 parts of silica sol by weight, the temperature is controlled at 52℃, and the stirring reaction is carried out for 3.5h, and then the activated sol is obtained after centrifugation and ethanol washing treatment in sequence; ② in-situ synthesis: the activated sol is dispersed in DMF to form a sol solution with a solid content of 10%, then zinc nitrate is added and uniformly dispersed by ultrasonic, and the zinc ion concentration is controlled at 0.1mol / L, finally 2-methyl imidazole is added and the molar ratio of the addition amount to zinc nitrate is controlled at 4:1, the stirring reaction is carried out at a temperature of 32℃ for 28h, and then the loaded silica sol is obtained after washing and drying in sequence; ③ post-functionalization: the loaded silica sol is dispersed in 1g / L of perfluorooctyl ethyl acetate ethanol solution, perfluorooctyl ethyl acetate is filled by vacuum impregnation method with a vacuum degree of 0.05Pa, a temperature of 25℃ and a time of 8h, the solid-liquid ratio is controlled at 1:15, and the modified silica sol with a mass loading of 17.93% is obtained after drying treatment at a temperature of 38℃ for 5h.

[0070] In step ①, the centrifugation is controlled at a rotation speed of 9000r / min for 20min. In step ②, the washing is carried out by using DMF and methanol for 3 times alternately, and the drying is carried out by vacuum drying treatment at 60℃ for 12h.

[0071] A preparation method of a high-density ceramic coating, for preparing a high-density ceramic coating as described above, comprising the following steps:

[0072] Step 1, material preparation: 35 parts of silica sol, 45 parts of solvent, 0.42 parts of glacial acetic acid and 19.9 parts of additives are prepared by mass fraction;

[0073] Step 2, basic mixing: the solvent is taken and the silica sol is added to the solvent, after stirring uniformly, the weak acid buffer is added and the pH is adjusted to 4.4, and then the silica sol-solvent system is obtained by stirring;

[0074] Step 3, additive dispersion: the additives are added to the silica sol-solvent system, the additives include TiO2, CM-F3 ceramic powder, CM-B silicon flake powder, Cu-Cr antibacterial agent, nano silicon dioxide, fused silica, leveling agent and wear-resistant material; and the additives are added in the following order: TiO2, CM-F3 ceramic powder and CM-B silicon flake powder are added first, and the rotation speed of the dispersing machine is increased to 1200r / min for stirring for 15min; then the Cu-Cr antibacterial agent is added, the rotation speed is maintained for stirring for 10min, and then the nano silicon dioxide and the fused silica are added, and the rotation speed is reduced to 1000r / min for stirring for 12min; finally, the leveling agent and the wear-resistant material are added, the rotation speed is controlled at 900r / min for stirring for 8min, and the coarse mixing system is obtained;

[0075] Step 4, grinding regulation: the crude mixture is transferred to a sand mill, and a grinding system with D50≤2 μm, D90≤5 μm and viscosity of 300-500 mPa·s is obtained after grinding treatment;

[0076] Step 5, filtration and packaging: the grinding system is filtered by a filter membrane, and is sealed and packaged under the protection of inert gas.

[0077] Example Four

[0078] The difference between Example Four and Example Two is that the SiO2 sol in Example Four is a modified silica sol with graphene quantum dots grown in situ.

[0079] The in-situ growth of graphene quantum dots in the SiO2 sol includes the following steps: Step ① backup composition: 5 parts of citric acid and 2.9 parts of urea are taken by weight and added to 20 parts of deionized water, and the mixture is stirred until completely dissolved to obtain a GQDs precursor solution; Step ② in-situ growth: the GQDs precursor solution is mixed with 40 parts of a silica sol ethanol solution, and the mass ratio of silica sol to ethanol in the silica sol ethanol solution is 3:1, the reaction is carried out at a temperature of 180℃ for 8h, and the heating rate is controlled at 5℃ / min, to obtain a growth material; Step ③ purification and optimization: the growth material is cooled to room temperature, filtered by a filter membrane, and then subjected to dialysis treatment and stabilizer stirring treatment in sequence, 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 filter membrane, the dialysis treatment is performed using a dialysis bag with a molecular weight cut-off of 1000 Da, and the dialysis time is 72h. The stabilizer is 0.1 g / L polyvinylpyrrolidone, and the stirring speed for stirring treatment is controlled at 300 r / min, and the stirring time is 30 min.

[0081] Example Five

[0082] The difference between Example Five and Example Four is that the in-situ growth of graphene quantum dots in the SiO2 sol in Example Five includes the following steps: Step ① backup composition: 5 parts of citric acid and 3 parts of urea are taken by weight and added to 20 parts of deionized water, and the mixture is stirred until completely dissolved to obtain a GQDs precursor solution; Step ② in-situ growth: the GQDs precursor solution is mixed with 40 parts of a silica sol ethanol solution, and the mass ratio of silica sol to ethanol in the silica sol ethanol solution is 3:1, the reaction is carried out at a temperature of 180℃ for 9h, and the heating rate is controlled at 5℃ / min, to obtain a growth material; Step ③ purification and optimization: the growth material is cooled to room temperature, filtered by a filter membrane, and then subjected to dialysis treatment and stabilizer stirring treatment in sequence, to obtain a modified silica sol with a mass growth rate of 2.17%.

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

[0084] Example Six

[0085] The difference between Example Six and Example Four is that the graphene quantum dot in-situ growth of the SiO2 sol in Example Six includes the following steps: Step ① backup composition: 5 parts of citric acid and 3.1 parts of urea are taken by weight, and 20 parts of deionized water is added, stirred until completely dissolved, and a GQDs precursor solution is obtained; Step ② in-situ growth: the GQDs precursor solution is mixed with 40 parts of a silicon sol ethanol solution, and the mass ratio of silicon sol to ethanol in the silicon sol ethanol solution is 3:1, the reaction is carried out at a temperature of 180℃ for 10 h, and the heating rate is controlled at 5℃ / min, and a growth material is obtained; Step ③ purification and optimization: the growth material is cooled to room temperature, filtered through a filter membrane, and then subjected to dialysis treatment and stabilizer stirring treatment in sequence, to obtain a modified silicon sol with a mass growth rate of 2.45%.

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

[0087] Example Seven

[0088] The difference between Example Seven and Example Four is that the SiO2 sol in Example Seven is not subjected to metal organic framework loading.

[0089] 45 nm SiO2 sol is loaded with metal organic framework, and 15-20 nm SiO2 sol is subjected to graphene quantum dot in-situ growth.

[0090] Comparative Example One

[0091] The difference between Comparative Example One and Example Two is that the SiO2 sol in Comparative Example One is not subjected to metal organic framework loading.

[0092] Comparative Example Two

[0093] The difference between Comparative Example Two and Example Four is that the SiO2 sol in Comparative Example Two is not subjected to graphene quantum dot in-situ growth.

[0094] Performance Test:

[0095] The performance tests of the above examples and comparative examples are as follows:

[0096] 1. Wear resistance test: test the mass loss rate after 5000 rubs according to GB / T 1768-2021 Paints and varnishes-Determination of abrasion resistance;

[0097] 2. High temperature resistance test: test the adhesion grade after 700℃, 2h according to GB / T 1735-2009 Paints, varnishes and raw materials for paints and varnishes;

[0098] 3. Service life test: test the discoloration grade, adhesion and mass loss rate after 3000h accelerated aging according to 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] Wear resistance High temperature resistance Service life Example one 0.86 2nd grade Chromatism 3rd grade; adhesion 2nd grade; loss rate 1.20% Example two 0.63 1st grade Chromatism 4th grade; adhesion 1st grade; loss rate 0.9% Example three 0.59 1st grade Chromatism 4th grade; adhesion 1st grade; loss rate 0.85% Example four 0.72 2nd grade Chromatism 3rd grade; adhesion 2nd grade; loss rate 1% Example five 0.66 1st grade Chromatism 4th grade; adhesion 1st grade; loss rate 0.95% Example six 0.62 1st grade Chromatism 4th grade; adhesion 1st grade; loss rate 0.9% Example seven 0.56 1st grade Chromatism 4th grade; adhesion 1st grade; loss rate 0.85% Comparative example one 1.59 4th grade Chromatism 2nd grade; adhesion 4th grade; loss rate 2.1% Comparative example two 1.40 4th grade Chromatism 2nd grade; adhesion 3rd grade; loss rate 1.95%

[0102] From the above Table 1, it can be seen that in the present application, the modified silica sol loaded with metal organic framework or in-situ grown with graphene quantum dots is used to replace the original sol, so as to significantly improve the wear resistance of the coating prepared by the high-density ceramic coating. Among them, since the metal organic framework has a porous structure, when it is loaded on the surface of the SiO2 sol, it will significantly increase the binding force between the particles in the coating, so as to reduce the particle shedding during friction by forming a dense network structure. At the same time, the graphene quantum dots have excellent mechanical properties, which are in-situ grown on the surface of the SiO2 sol, so as to form a strong nano-reinforced phase structure in the coating to achieve the purpose of dispersing friction stress and reducing the wear of the coating. And in Example Seven of the present application, it can be found that the synergistic effect of the composite modification based on the 45nm SiO2 sol loaded with metal organic framework and the 20nm SiO2 sol in-situ grown with graphene quantum dots will make the coating have the most excellent wear resistance, and the mass loss rate after 5000 rubs is only 0.56%.

[0103] As can be seen from Comparative Example One and Comparative Example Two, since the SiO2 sol is not loaded with metal organic framework, the binding force of the particles in the coating is weak, there are many voids, which makes the particles easily fall off during friction, resulting in a mass loss rate of 1.59%. Compared with this, the SiO2 sol in Comparative Example Two is not in-situ grown with graphene quantum dots, so it lacks the structure of nano-reinforced phase, which makes it difficult to effectively disperse the friction stress, so its wear resistance is poor, and the mass loss rate is also 1.4%, which is much higher than the mass loss rate of the coating in the present application.

[0104] In terms of high temperature resistance, since the decomposition products of the metal organic framework loaded SiO2sol are generated after partial decomposition of the SiO2sol at high temperature, the decomposition products, SiO2sol and other components are mutually synergistic and form stable high temperature resistant phases, thereby effectively preventing the generation and diffusion of thermal stress in the coating, achieving the purpose of reducing the cracking and peeling problems of the coating. And when the graphene quantum dots grow in situ on the surface of the SiO2sol, it will have the effect of quickly conducting the heat in the coating and effectively avoiding the destruction of the coating caused by local high temperature, thereby making the coating maintain its structural integrity at high temperature. Based on this, in Comparative Example 1, the SiO2sol is not loaded by the metal organic framework, so that it is easy to produce thermal stress concentration in the coating at high temperature, and further cause the coating to crack and the adhesion to decrease, so that the adhesion grade at 700°C is only 4. In Comparative Example 2, the SiO2sol is not in situ grown with graphene quantum dots, so that the coating has poor thermal conductivity, and further causes the adhesion grade to decrease to 3-4 due to local high temperature.

[0105] In terms of service life, since the SiO2sol in Comparative Examples 1 and 2 is not modified, it can be found from the test data that the coating density and aging resistance of the high density ceramic coating prepared by the corresponding comparative examples are poor, and after 3000h of accelerated aging, the chemical bonds of the coating are broken and the structure is destroyed. Therefore, the discoloration grade is reduced to 2-3, the adhesion grade is reduced to 3-4, and the wear resistance is reduced to 1.80%-2.00%, thereby shortening the service life of the corresponding Comparative Example 1 and Comparative Example 2.

[0106] In summary, the application provides a high-density ceramic coating and a preparation method thereof. The ZIF-8 nanoparticles in the metal organic framework loaded modified silica sol are covalently combined with the surface hydroxyl groups of the silica sol through APTES, forming a core / shell structure, so that the porous structure formed thereby stores a small amount of perfluorooctanoic acid ethyl ester during friction, achieving the effects of micro-lubrication and reducing the friction coefficient. Specifically, in the modified silica sol of graphene quantum dots, a sliding layer is formed on the surface of the coating through the sheet structure of GQDs, thereby effectively reducing the interfacial shear force during friction. At the same time, GQDs and the siloxane network synergistically improve the density of the coating, effectively reducing the problem of wear expansion caused by the invasion of wear particles. At the same time, the cross-linked network structure of Si-O-Si is generated after the hydrolysis of MTMS in the solvent at high temperature, which is not easy to break; and the interpenetrating network structure is formed between MTMS and SiO2 particles in the silica sol, effectively inhibiting the thermal expansion of the coating at high temperature and reducing the cracking caused by thermal stress. In order to ensure that the coating obtained by the high-density ceramic coating still maintains low surface energy after high-temperature use, perfluorooctanoic acid ethyl ester is loaded in the channel of ZIF-8, so that the channel restriction of ZIF-8 prevents the volatilization loss of functional molecules at high temperature; and the weak interaction between perfluorooctanoic acid ethyl ester and the siloxane network enhances the stability at high temperature. And when the fused silica and nanosilica are used to synergistically fill the internal pores of the coating, a dense structure is formed, which effectively blocks the invasion of corrosion media such as water, oxygen and detergents, while reducing the hydrolysis and oxidation of the coating matrix.

[0107] The terms "first", "second", "third", "fourth" and the like, if any, used in this application are used to distinguish similar objects, and do not necessarily have to be used to describe a particular order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments described herein can be implemented in an order other than that described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods or devices.

[0108] It should be noted that the terms "first", "second", and the like in the description and in the claims do not denote any particular importance, but are merely used to distinguish one element from another. Thus, a "first" and "second" feature can be presented explicitly or implicitly, and can include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection required by the present application.

[0109] The principles and implementation manners of the present application are described by applying specific examples herein, and the above description of the examples is only for helping to understand the method of the present application and its core idea; meanwhile, for those skilled in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application, and in view of the above, the content of the specification should not be understood as limiting the present application.

Claims

1. A high density ceramic coating, characterized by: The solvent comprises 25.5-26.5 parts by mass of MTMS, 0.5 parts of deionized water and 16-19 parts of ethanol; the silica sol comprises 25.5-26.5 parts by mass of 45 nm SiO2 sol and 15-20 nm SiO2 sol as the balance, and the SiO2 sol is a modified silica sol loaded with a metal organic framework or in-situ grown with a graphene quantum dot; The metal organic framework loading of the SiO2 sol comprises the following steps: ① surface activation: 1.5-1.55 parts by weight of 3-aminopropyl triethoxysilane and 47-53 parts of ethanol are added to 38-42 parts by weight of silica sol, the temperature is controlled at 48-52 ℃, and stirring reaction is carried out for 3-3.5 h, and then the activated sol is obtained after centrifugation and ethanol washing treatment in sequence; 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 uniformly dispersed by ultrasonic, and the zinc ion concentration is controlled at 0.09-0.12 mol / L, 2-methyl imidazole is finally added, and the molar ratio of the addition amount to zinc nitrate is controlled at 4:1, stirring reaction is carried out at a temperature of 30-32 ℃ for 20-28 h, and then the loaded silica sol is obtained after washing and drying in sequence; ③ post-functionalization: the loaded silica sol is dispersed in 1-1.1 g / L of a perfluorooctanoic acid ethyl ester ethanol solution, perfluorooctanoic acid ethyl ester is filled by a vacuum impregnation method with a vacuum degree of 0.05 Pa, a temperature of 25 ℃ and a time of 8-10 h, the solid-liquid ratio is controlled at 1:12-15, and the modified silica sol with a mass loading of 10-20% is obtained after drying treatment at a temperature of 35-42 ℃ for 4-5 h; The in-situ growth of the graphene quantum dot of the SiO2 sol comprises the following steps: ① backup composition: 5-5.2 parts by weight of citric acid and 2.9-3.1 parts of urea are taken and added to 20-22 parts of deionized water, stirring is carried out until complete dissolution, and a GQDs precursor solution is obtained; ② in-situ growth: the GQDs precursor solution is mixed with 38-42 parts of a silica sol ethanol solution, and the mass ratio of the silica sol to ethanol in the silica sol ethanol solution is 3:1, the growth material is obtained after reaction at a temperature of 180-182 ℃ for 8-10 h with a temperature rising rate of 5-6 ℃ / min; ③ purification and optimization: the growth material is cooled to room temperature, filtered through a filter membrane, and then treated by dialysis and a stabilizer stirring treatment in sequence, and the modified silica sol with a mass growth rate of 1.2-2.8% is obtained. The weak acid buffer is glacial acetic acid.

2. A high density ceramic coating according to claim 1, characterized in that: ​ 3. A high density ceramic coating according to claim 1, characterized in that: In the step ① of loading the metal organic framework of the SiO2 sol, the centrifugation is controlled at 7000-9000r / min for 18-22min; in the step ② of loading the metal organic framework of the SiO2 sol, the washing is performed by using DMF and methanol alternately for 3-10 times, and the drying is performed by vacuum drying at 58-62℃ for 12-14h.

4. The high density ceramic coating of claim 1, wherein: In the step ③ of in-situ growth of the graphene quantum dots of the SiO2 sol, the filter membrane is 0.22-0.3μm filter membrane; the dialysis treatment is performed by using a dialysis bag with a controlled molecular weight cut-off of 800Da or 1000Da for 72-96h; the stabilizer is 0.1-0.11g / L polyvinylpyrrolidone, and the stirring speed of the stirring treatment is controlled at 300-400r / min for 30min.

5. A method for the preparation of a high density ceramic coating for the preparation of a high density ceramic coating according to any one of claims 1 to 4, characterized in that Comprising the following steps: Step 1, material preparation: 33-35 parts of silica sol, 43-45 parts of solvent, 0.35-0.42 parts of weak acid buffer and 18.5-19.9 parts of auxiliary agent are prepared for use; Step 2, basic mixing: the solvent is taken and the silica sol is added thereto, after stirring uniformly, the weak acid buffer is added and the pH is adjusted to 4.0-4.5, and the silica sol-solvent system is obtained by stirring; Step 3, auxiliary agent dispersion: the auxiliary agent is added to the silica sol-solvent system, and the coarse mixing system is obtained by stirring; Step 4, grinding control: the coarse mixing system is transferred to the sand mill, and the grinding system with D50≤2μm, D90≤5μm and viscosity of 300-500mPa·s is obtained after grinding treatment; Step 5, filtration and packaging: the grinding system is filtered by using a filter membrane, and is sealed and packaged under the protection of inert gas.