A polysilazane-based green special refractory ceramic coating and its preparation method

Abstract

The present invention provides a polysilazane-based green special refractory ceramic coating and a preparation method thereof, belonging to the field of ceramic coatings. The present invention provides high hardness, oxidation resistance, thermal shock resistance and excellent thermal stability with a ternary core material composed of titanium carbide, zirconium boride and silicon nitride; the silica-alumina composite shell layer significantly improves the oxidation resistance and reliability of the coating through synergistic oxidation resistance and crack self-repairing functions; the polymetallic oxygen cluster network gives the coating excellent electrical conductivity, thermal conductivity and corrosion resistance; the intercalated montmorillonite enhances the crack resistance and oxidation resistance through the layered structure and embedded active ions; the boron nitride-coated vanadium carbide particles provide lubricity, oxidation resistance and wear resistance. The synergistic optimization between multiple components comprehensively improves the comprehensive performance of the coating in terms of oxidation resistance, thermal conductivity, interface stability, high temperature performance and mechanical properties, so that it exhibits excellent long-term stability and functionality in extreme environments.

Description

Technical Field

[0001] The invention belongs to the technical field of green special refractory ceramic coatings and relates to a polysilazane-based green special refractory ceramic coating and a preparation method thereof. Background Art

[0002] Polysilazane-based green specialty refractory ceramic coatings, due to their outstanding high-temperature, corrosion, and oxidation resistance, have attracted increasing attention in the field of materials science and have become a key area of ​​research in high-temperature materials. Suitable for use in extreme environments, these coatings effectively maintain structural stability and chemical inertness, making them widely used in critical components operating under high-temperature conditions in sectors such as aerospace, automotive, and energy. For example, in aircraft engines, turbine blades must withstand extremely high temperatures and pressures, and the application of polysilazane-based coatings can significantly improve the durability and performance of these components. Furthermore, the application of these coatings has also improved the thermal efficiency and service life of equipment such as heat exchangers, driving advancements in related technologies.

[0003] However, despite the numerous advantages of polysilazane-based green specialty refractory ceramic coatings, existing technologies still have some shortcomings that urgently require further research and improvement. First, traditional ceramic coatings are prone to thermal stress concentration under high-temperature conditions. This concentration can lead to the initiation and propagation of cracks, ultimately causing the coating to peel. This not only affects the long-term stability and service life of the coating but can also cause damage to the substrate, posing a serious safety hazard. This situation is particularly pronounced in high-load and high-temperature environments, posing a significant risk to the operation of related equipment.

[0004] Secondly, existing polysilazane-based ceramic coatings lack satisfactory toughness and thermal shock resistance. Under extreme conditions of rapid temperature fluctuations, the coatings often fail to maintain their integrity and functionality. This fragility limits their reliability and effectiveness in cutting-edge technological applications. This limitation not only restricts the coating's application scope but also hinders its further development in the field of high-performance materials. Summary of the Invention

[0005] In response to the above problems, the purpose of the present invention is to provide a polysilazane-based green special refractory ceramic coating and a preparation method thereof. This system constructs a high-performance coating through scientific design and multi-component synergy. The ternary core material composed of titanium carbide, zirconium boride and silicon nitride provides high hardness, oxidation resistance, thermal shock resistance and excellent thermal stability; the silica-alumina composite shell significantly improves the oxidation resistance and reliability of the coating through synergistic oxidation resistance and crack self-repairing functions; the multi-metal oxygen cluster network gives the coating excellent electrical conductivity, thermal conductivity and corrosion resistance; the intercalated montmorillonite enhances the crack resistance and oxidation resistance through the layered structure and embedded active ions; the boron nitride-coated vanadium carbide particles provide lubricity, oxidation resistance and wear resistance. The synergistic optimization between multiple components comprehensively improves the comprehensive performance of the coating in terms of oxidation resistance, thermal conductivity, interface stability, high temperature performance and mechanical properties, so that it exhibits excellent long-term stability and functionality in extreme environments.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a polysilazane-based green special refractory ceramic coating, the method for preparing the polysilazane-based green special refractory ceramic coating comprising:

[0008] S1: Titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol with oleic acid, then ball-milled, separated, dried, and sintered at high temperature to obtain a ternary core;

[0009] S2: a mixed solution of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and aluminum nitrate is mixed and reacted with an anhydrous ethanol dispersion of the ternary core, followed by aging, separation, drying, and calcination to obtain a ternary core@self-healing oxide composite material;

[0010] S3: ammonium molybdate and ammonium tungstate are mixed with pyridine in deionized water, the pH is adjusted, and then reacted, separated, dried, and pyrolyzed to obtain a functionalized metal cluster network.

[0011] S4: After ultrasonic exfoliation of the montmorillonite, the montmorillonite is reacted with a mixed solution of ammonium metavanadate and cerium nitrate, and the intercalated modified montmorillonite is obtained by separation, drying and calcination;

[0012] S5: reacting vanadium trichloride with glucose in anhydrous ethanol under high pressure, and obtaining vanadium carbide through separation, drying and heat treatment;

[0013] S6: dispersing boric acid, urea and vanadium carbide in N,N-dimethylformamide with a dispersant, and then preparing boron nitride-coated vanadium carbide through atomization and heat treatment processes;

[0014] S7: Disperse polysilazane in anhydrous toluene, add a crosslinker, dispersant, catalyst and coupling agent, and then add the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalated modified montmorillonite and boron nitride-coated vanadium carbide in sequence. After dispersion and degassing, the coating is obtained, which is sprayed on the surface of the substrate and cured to obtain a polysilazane-based green special refractory ceramic coating.

[0015] Specifically, S1: titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol, oleic acid is added to obtain a solution, the solution is ball-milled in a silicon nitride ball mill, centrifuged, washed, and dried to obtain a mixture; the mixture is sintered under a nitrogen atmosphere, naturally cooled to room temperature, and then ground to obtain a ternary core;

[0016] S2: Mixing ethyl orthosilicate with anhydrous ethanol and deionized water to obtain a mixed solution A, preparing an aluminum nitrate solution, and mixing the mixed solution with the mixed solution A to obtain a mixed solution. Ultrasonic dispersion of the ternary core in anhydrous ethanol is followed by dropwise addition of the mixed solution to obtain a reaction solution B. After stirring and aging at room temperature, the pretreated material is filtered, washed, and dried to obtain a pretreated material, which is then calcined in a nitrogen / air atmosphere to obtain a ternary core@self-healing oxide composite material.

[0017] S3: Dissolve ammonium molybdate and ammonium tungstate in deionized water, add pyridine, and adjust the pH with nitric acid to obtain a reaction solution C. After stirring, filter, wash, and pre-dry to obtain a crude product, which is pyrolyzed under a nitrogen atmosphere to obtain a functionalized metal cluster network;

[0018] S4: ultrasonically exfoliating the montmorillonite for later use; preparing an ammonium metavanadate solution and a cerium nitrate solution, mixing the ammonium metavanadate solution and the cerium nitrate solution, adding the exfoliated montmorillonite, and ultrasonically mixing to obtain a reaction solution D, which is transferred to a high-pressure reactor for hydrothermal reaction, centrifuged, washed, freeze-dried, and then calcined under a nitrogen / air atmosphere to obtain intercalated modified montmorillonite;

[0019] S5: Dissolving vanadium trichloride in anhydrous ethanol under a nitrogen atmosphere, adding glucose and stirring to obtain a reaction solution E, transferring the reaction solution into a high-pressure reactor, filtering, washing, pre-drying, and then heat-treating under a nitrogen atmosphere to obtain vanadium carbide;

[0020] S6: mixing boric acid and urea and dispersing them in N,N-dimethylformamide to obtain a boric acid mixture, dispersing vanadium carbide in N,N-dimethylformamide and adding a dispersant BYK-11 to obtain a vanadium carbide dispersion, mixing the boric acid mixture and the vanadium carbide dispersion, stirring, and then spraying through an atomizer to obtain a precursor, which is heat-treated under a nitrogen atmosphere to obtain boron nitride-coated vanadium carbide;

[0021] S7: Disperse polysilazane in anhydrous toluene, add a cross-linking agent, a dispersant, a catalyst and a coupling agent and stir evenly to form a base liquid, add the ternary core@self-healing oxide composite material, the functionalized metal cluster network, the intercalated modified montmorillonite and the boron nitride-coated vanadium carbide to the base liquid respectively, stir and disperse, and vacuum degas to obtain a coating, which is sprayed on the surface of the substrate and cured to obtain a polysilazane-based green special refractory ceramic coating.

[0022] As a preferred technical solution of the present invention, in step S1, the total solid content of the titanium carbide, zirconium boride, and silicon nitride dispersed in anhydrous ethanol is 15-20 wt.%, for example, it can be 15.0 wt.%, 15.5 wt.%, 16.0 wt.%, 16.5 wt.%, 17.0 wt.%, 17.5 wt.%, 18.0 wt.%, 18.5 wt.%, 19.0 wt.%, 19.5 wt.% or 20.0 wt.%, but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0023] In some optional embodiments, the mass fraction of oleic acid in the solution is 0.3-0.7 wt.%, for example, it can be 0.30 wt.%, 0.34 wt.%, 0.38 wt.%, 0.42 wt.%, 0.46 wt.%, 0.50 wt.%, 0.54 wt.%, 0.58 wt.%, 0.62 wt.%, 0.66 wt.% or 0.70 wt.%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0024] In some optional embodiments, the sintering temperature of the mixture is 1550-1650°C, for example, it can be 1550°C, 1560°C, 1570°C, 1580°C, 1590°C, 1600°C, 1610°C, 1620°C, 1630°C, 1640°C or 1650°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0025] In some optional embodiments, the sintering time of the mixture is 10-15 min, for example, it can be 10.0 min, 10.5 min, 11.0 min, 11.5 min, 12.0 min, 12.5 min, 13.0 min, 13.5 min, 14.0 min, 14.5 min or 15.0 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] In some optional embodiments, the pressure during sintering of the mixture is 35-45 MPa, for example, it can be 35 MPa, 36 MPa, 37 MPa, 38 MPa, 39 MPa, 40 MPa, 41 MPa, 42 MPa, 43 MPa, 44 MPa or 45 MPa, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0027] As a preferred technical solution of the present invention, in step S2, the molar ratio of the ethyl orthosilicate to anhydrous ethanol is 1:(3-4), for example, it can be 1:3.0, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9 or 1:4.0, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] In some optional embodiments, the molar ratio of the ethyl orthosilicate to deionized water is 1:(2-3), for example, it can be 1:2.0, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9 or 1:3.0, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0029] In some optional embodiments, the concentration of the aluminum nitrate solution is 1-2M, for example, it can be 1.0M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M, 1.6M, 1.7M, 1.8M, 1.9M or 2.0M, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] In some optional embodiments, the molar ratio of tetraethyl orthosilicate to aluminum nitrate is (2-3):1, for example, it can be 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1 or 3.0:1, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0031] In some optional embodiments, the mass ratio of the ternary core to anhydrous ethanol is 1:90-100, for example, it can be 1:90, 1:91, 1:92, 1:93, 1:94, 1:95, 1:96, 1:97, 1:98, 1:99 or 1:100, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0032] In some optional embodiments, the dropping speed of the mixed solution is 1-2 mL / min, for example, it can be 1.0 mL / min, 1.1 mL / min, 1.2 mL / min, 1.3 mL / min, 1.4 mL / min, 1.5 mL / min, 1.6 mL / min, 1.7 mL / min, 1.8 mL / min, 1.9 mL / min or 2.0 mL / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] In some optional embodiments, the mass ratio of the ternary core to tetraethyl orthosilicate is 1:(10-15), for example, it can be 1:10.0, 1:10.5, 1:11.0, 1:11.5, 1:12.0, 1:12.5, 1:13.0, 1:13.5, 1:14.0, 1:14.5 or 1:15.0, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0034] In some optional embodiments, the stirring temperature of the reaction liquid B is 50-60°C, for example, it can be 50.0°C, 51.0°C, 52.0°C, 53.0°C, 54.0°C, 55.0°C, 56.0°C, 57.0°C, 58.0°C, 59.0°C or 60.0°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0035] In some optional embodiments, the stirring time of the reaction liquid B is 3-4h, for example, it can be 3.0h, 3.1h, 3.2h, 3.3h, 3.4h, 3.5h, 3.6h, 3.7h, 3.8h, 3.9h or 4.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] In some optional embodiments, the room temperature aging time is 10-12h, for example, it can be 10.0h, 10.2h, 10.4h, 10.6h, 10.8h, 11.0h, 11.2h, 11.4h, 11.6h, 11.8h or 12.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In some optional embodiments, the calcination temperature of the pretreated material is 750-800°C, for example, it can be 750°C, 755°C, 760°C, 765°C, 770°C, 775°C, 780°C, 785°C, 790°C, 795°C or 800°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0038] In some optional embodiments, the calcination time of the pretreated material is 2-3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] As a preferred technical solution of the present invention, in step S3, the molar ratio of ammonium molybdate to ammonium tungstate is (1-2):1, for example, it can be 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2.0:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] In some optional embodiments, the concentration of ammonium tungstate is 0.1-0.2M, for example, it can be 0.10M, 0.11M, 0.12M, 0.13M, 0.14M, 0.15M, 0.16M, 0.17M, 0.18M, ​​0.19M or 0.20M, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] In some optional embodiments, the molar ratio of ammonium molybdate to pyridine is 1:(2-3), for example, 1:2.0, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9 or 1:3.0, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] In some optional embodiments, the concentration of nitric acid is 1-2M, for example, it can be 1.0M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M, 1.6M, 1.7M, 1.8M, 1.9M or 2.0M, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] In some optional embodiments, the pH is adjusted to 6-7 with nitric acid, for example, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 or 7.0, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] In some optional embodiments, the stirring temperature of the reaction liquid C is 65-70°C, for example, it can be 65.0°C, 65.5°C, 66.0°C, 66.5°C, 67.0°C, 67.5°C, 68.0°C, 68.5°C, 69.0°C, 69.5°C or 70.0°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0045] In some optional embodiments, the stirring time of the reaction liquid C is 5-6h, for example, it can be 5.0h, 5.1h, 5.2h, 5.3h, 5.4h, 5.5h, 5.6h, 5.7h, 5.8h, 5.9h or 6.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In some optional embodiments, the pre-drying temperature is 70-80°C, for example, it can be 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C or 80°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] In some optional embodiments, the pre-drying time is 10-12 hours, for example, it can be 10.0 hours, 10.2 hours, 10.4 hours, 10.6 hours, 10.8 hours, 11.0 hours, 11.2 hours, 11.4 hours, 11.6 hours, 11.8 hours or 12.0 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] In some optional embodiments, the temperature of pyrolysis of the crude product is 450-550°C, for example, it can be 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0049] In some optional embodiments, the pyrolysis time of the crude product is 2-3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] As a preferred technical solution of the present invention, in step S4, the concentration of the ammonium metavanadate solution is 0.1-0.12M, for example, it can be 0.100M, 0.102M, 0.104M, 0.106M, 0.108M, 0.110M, 0.112M, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0051] In some optional embodiments, the concentration of the cerium nitrate solution is 0.08-0.12M, for example, it can be 0.080M, 0.084M, 0.088M, 0.092M, 0.096M, 0.100M, 0.104M, 0.108M, 0.112M, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0052] In some optional embodiments, the molar ratio of ammonium metavanadate to cerium nitrate is 1:(1-2), for example, it can be 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.0, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] In some optional embodiments, the mass ratio of the montmorillonite to the total mass of ammonium metavanadate and cerium nitrate is (8-10):1, for example, it can be 8.0:1, 8.2:1, 8.4:1, 8.6:1, 8.8:1, 9.0:1, 9.2:1, 9.4:1, 9.6:1, 9.8:1 or 10.0:1, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0054] In some optional embodiments, the temperature of the hydrothermal reaction is 175-185°C, for example, it can be 175°C, 176°C, 177°C, 178°C, 179°C, 180°C, 181°C, 182°C, 183°C, 184°C or 185°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0055] In some optional embodiments, the hydrothermal reaction time is 22-26 hours, for example, it can be 22.0 hours, 22.4 hours, 22.8 hours, 23.2 hours, 23.6 hours, 24.0 hours, 24.4 hours, 24.8 hours, 25.2 hours, 25.6 hours or 26.0 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] In some optional embodiments, the calcination temperature is 680-720°C, for example, it can be 680°C, 684°C, 688°C, 692°C, 696°C, 700°C, 704°C, 708°C, 712°C, 716°C or 720°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] In some optional embodiments, the calcination time is 2-3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0058] As a preferred technical solution of the present invention, in step S5, the concentration of the vanadium trichloride in anhydrous ethanol is 0.1-0.2M, for example, it can be 0.10M, 0.11M, 0.12M, 0.13M, 0.14M, 0.15M, 0.16M, 0.17M, 0.18M, ​​0.19M or 0.20M, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0059] In some optional embodiments, the molar ratio of vanadium trichloride to glucose is 1:(1-1.2), for example, it can be 1:1.00, 1:1.02, 1:1.04, 1:1.06, 1:1.08, 1:1.10, 1:1.12, 1:1.14, 1:1.16, 1:1.18 or 1:1.20, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] In some optional embodiments, the stirring temperature is 60-70°C, for example, it can be 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C or 70°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0061] In some optional embodiments, the stirring time is 1-2h, for example, it can be 1.0h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0062] In some optional embodiments, the reaction temperature of the reaction liquid E in the high-pressure reactor is 170-180°C, for example, it can be 170°C, 171°C, 172°C, 173°C, 174°C, 175°C, 176°C, 177°C, 178°C, 179°C or 180°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0063] In some optional embodiments, the reaction time of the reaction liquid E in the high-pressure reactor is 10-12 hours, for example, it can be 10.0 hours, 10.2 hours, 10.4 hours, 10.6 hours, 10.8 hours, 11.0 hours, 11.2 hours, 11.4 hours, 11.6 hours, 11.8 hours or 12.0 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0064] In some optional embodiments, the temperature of the heat treatment is 1000-1100°C, for example, it can be 1000°C, 1010°C, 1020°C, 1030°C, 1040°C, 1050°C, 1060°C, 1070°C, 1080°C, 1090°C or 1100°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0065] In some optional embodiments, the heat treatment time is 2-3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0066] As a preferred technical solution of the present invention, in step S6, the molar ratio of boric acid to urea is (2-3):1, for example, it can be 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1 or 3.0:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0067] In some optional embodiments, the total concentration of the boric acid and uric acid dispersed in N,N-dimethylformamide is 1-2M, for example, it can be 1.0M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M, 1.6M, 1.7M, 1.8M, 1.9M or 2.0M, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0068] In some optional embodiments, the mass ratio of the vanadium carbide to N,N-dimethylformamide is 1:(100-150), for example, it can be 1:100, 1:105, 1:110, 1:115, 1:120, 1:125, 1:130, 1:135, 1:140, 1:145 or 1:150, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0069] In some optional embodiments, the mass ratio of the vanadium carbide to the dispersant BYK-111 is 90-100:1, for example, it can be 90:1, 91:1, 92:1, 93:1, 94:1, 95:1, 96:1, 97:1, 98:1, 99:1 or 100:1, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0070] In some optional embodiments, the mass ratio of the vanadium carbide to boric acid is 1:(0.3-0.5), for example, it can be 1:0.30, 1:0.32, 1:0.34, 1:0.36, 1:0.38, 1:0.40, 1:0.42, 1:0.44, 1:0.46, 1:0.48 or 1:0.50, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0071] In some optional embodiments, the stirring temperature is 70-75°C, for example, it can be 70°C, 70.5°C, 71°C, 71.5°C, 72°C, 72.5°C, 73°C, 73.5°C, 74°C, 74.5°C or 75°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0072] In some optional embodiments, the stirring time is 3-4h, for example, it can be 3.0h, 3.1h, 3.2h, 3.3h, 3.4h, 3.5h, 3.6h, 3.7h, 3.8h, 3.9h or 4.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0073] In some optional embodiments, the inlet temperature of the atomizer is 190-200°C, for example, it can be 190°C, 191°C, 192°C, 193°C, 194°C, 195°C, 196°C, 197°C, 198°C, 199°C or 200°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0074] In some optional embodiments, the outlet temperature of the atomizer is 95-100°C, for example, it can be 95°C, 95.5°C, 96°C, 96.5°C, 97°C, 97.5°C, 98°C, 98.5°C, 99°C, 99.5°C or 100°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0075] In some optional embodiments, the temperature of the precursor heat treatment is 1300-1400°C, for example, it can be 1300°C, 1310°C, 1320°C, 1330°C, 1340°C, 1350°C, 1360°C, 1370°C, 1380°C, 1390°C or 1400°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0076] In some optional embodiments, the precursor heat treatment time is 2-3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0077] As a preferred technical solution of the present invention, in step S7, the mass fraction of the polysilazane dispersed in anhydrous toluene is 25-35 wt.%, for example, it can be 25 wt.%, 26 wt.%, 27 wt.%, 28 wt.%, 29 wt.%, 30 wt.%, 31 wt.%, 32 wt.%, 33 wt.%, 34 wt.% or 35 wt.%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0078] In some optional embodiments, the cross-linking agent is divinyldimethylsilane, and the amount of the cross-linking agent is 2-3% of the mass of the polysilazane, for example, it can be 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9% or 3.0%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0079] In some optional embodiments, the dosage of the dispersant is 1-2% of the mass of the polysilazane, for example, it can be 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2.0%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0080] In some optional embodiments, the catalyst is dibutyltin dilaurate, and the amount of the catalyst is 0.2-0.5% of the mass of the polysilazane, for example, it can be 0.2%, 0.23%, 0.26%, 0.29%, 0.32%, 0.35%, 0.38%, 0.41%, 0.44%, 0.47% or 2.0%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0081] In some optional embodiments, the coupling agent is isopropyl titanate, and the amount of the coupling agent is 1-2% of the mass of the polysilazane, for example, it can be 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2.0%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0082] In some optional embodiments, the curing temperature is 60-70°C, for example, it can be 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C or 70°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0083] In some optional embodiments, the curing time is 2-3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0084] In a second aspect, the present invention provides a polysilazane-based green specialty refractory ceramic coating. The polysilazane-based green specialty refractory ceramic coating comprises polysilazane, a ternary core@self-healing oxide composite material, a functionalized metal cluster network, intercalated modified montmorillonite, boron nitride-coated vanadium carbide, a crosslinker, a dispersant, a catalyst, and a coupling agent.

[0085] In the present invention, titanium carbide, zirconium boride and silicon nitride are selected as the basic raw materials to prepare the ternary core material. This combination fully utilizes the unique performance advantages of the three materials to achieve performance optimization and synergistic enhancement. Specifically, titanium carbide is a material with excellent mechanical and thermal properties. It has extremely high hardness, excellent thermal conductivity and oxidation resistance. In high temperature environments, titanium carbide exhibits excellent thermal stability, enabling it to maintain structural integrity and functional performance under high temperatures and extreme working conditions. In addition, the high hardness and wear resistance of titanium carbide make it an ideal material for resisting mechanical wear.

[0086] Zirconium boride, a representative material for ultra-high-temperature ceramics, exhibits exceptional oxidation resistance. Under high temperatures, a dense protective zirconium oxide layer forms on the surface of zirconium boride, preventing further oxidation. Furthermore, zirconium boride exhibits excellent chemical stability and wear resistance, enabling it to provide reliable protection in harsh environments. Furthermore, its high melting point and low density make it a key component of high-temperature coatings.

[0087] Silicon nitride is widely used in high-temperature environments due to its low density, high thermal shock resistance, and excellent mechanical properties. Compared to other ceramic materials, silicon nitride exhibits higher fracture toughness and thermal shock resistance, effectively resisting thermal stress damage caused by rapid temperature changes. Furthermore, its high hardness and chemical stability make it extremely durable in high-temperature environments. More importantly, it provides good interfacial bonding and thermal behavior matching when composited with other materials, thereby improving the overall performance of the composite material.

[0088] During the preparation process, anhydrous ethanol was used as the dispersion medium, and oleic acid was introduced as a surface modifier to achieve uniform dispersion and effective bonding of the three materials. Oleic acid contains a long-chain alkyl group and a terminal carboxyl group in its molecular structure. The carboxyl group binds to the surface through electrostatic adsorption and chemical bonding, forming a stable dispersant layer. Simultaneously, the long-chain alkyl group provides steric hindrance, significantly reducing the tendency for particles to agglomerate. This surface modification not only improves dispersion stability in the dispersion medium but also provides an excellent foundation for subsequent uniform mixing and sintering.

[0089] After the solution is fully ball-milled under a nitrogen atmosphere, the resulting homogeneous mixture is further sintered to form a ternary core. The sintering process is achieved through a solid-phase reaction and physical densification process at high temperature. Specifically, under nitrogen protective atmosphere conditions, diffusion occurs between particles at high temperatures, and the particle surfaces melt and rearrange, thereby forming sintering necks; as the temperature increases and the sintering time prolongs, the sintering necks between the particles gradually grow, and grain boundary migration further promotes the densification of the material. During this process, the pores between the particles gradually close, eventually forming a ternary core material with a higher density.

[0090] The nitrogen atmosphere plays multiple key roles during the sintering process. First, as an inert atmosphere, nitrogen effectively prevents oxidation of titanium carbide and zirconium boride at high temperatures. Titanium carbide and zirconium boride inherently possess excellent high-temperature performance, but in an oxidizing environment, they can form volatile or brittle oxides, which degrade the material's mechanical properties and thermal stability. Under nitrogen protection, these oxidation reactions are effectively suppressed, ensuring the structural integrity and functional performance of titanium carbide and zirconium boride.

[0091] Secondly, nitrogen also plays an important role in the stability of silicon nitride. At high temperatures, silicon nitride easily decomposes into silicon and nitrogen due to nitrogen escape, which significantly reduces its high-temperature performance. In a nitrogen atmosphere, silicon nitride forms a chemical equilibrium with the nitrogen in the gas phase, inhibiting its thermal decomposition reaction, thereby ensuring that silicon nitride can maintain its original structure and properties during the sintering process.

[0092] The ternary core material formed through the aforementioned sintering process exhibits high strength, high hardness, and excellent high-temperature stability. The mechanical properties of this core material are derived from the high hardness and wear resistance of titanium carbide, the oxidation resistance of zirconium boride, and the high thermal shock stability and toughness of silicon nitride. Its thermal properties, on the other hand, stem from the high melting points of these three materials, their uniform distribution at the microscale, and their excellent interfacial bonding. This complementary and synergistic combination of material properties provides a solid foundation for the mechanical and thermal properties of the final coating, enabling the overall coating to maintain excellent structural stability and functional performance in extremely high-temperature environments while meeting the comprehensive performance requirements of high strength, durability, and thermal shock resistance.

[0093] The present invention successfully constructed a ternary core@self-healing oxide composite material through the sol-gel method, making full use of the advantages of the sol-gel process in precisely controlling the material structure at the molecular level, providing the final core material with excellent antioxidant properties and high-temperature self-healing capabilities. During the preparation process, ethyl orthosilicate, as a silicon source, undergoes a hydrolysis reaction in a mixed reaction system of ethanol and water to generate a silanol intermediate. The silanol further forms a three-dimensional Si-O-Si bond network structure through a polycondensation reaction, gradually generating a uniformly distributed silica precursor. In this process, the sol-gel process ensures the uniformity of the reaction, enabling the silica to achieve high purity and high dispersibility at the molecular level. At the same time, aluminum nitrate is used as an aluminum source, and the aluminum ions released during the hydrolysis process undergo complexation with the silanol and the hydroxyl groups on the surface of the generated silica particles, and gradually deposit to form aluminum oxide. Through composite assembly, an aluminum oxide-silicon dioxide composite shell with a uniform structure is finally formed.

[0094] The combination of silica and alumina imparts remarkable functional properties to the shell. Silica itself is a key antioxidant. Its high melting point and excellent chemical inertness effectively block the attack of oxygen and other corrosive gases on the inner material. Alumina, with its even higher melting point and excellent thermal stability, further enhances the shell's antioxidant properties in high-temperature oxidizing environments. The composite structure of the two forms a synergistic antioxidant mechanism through interfacial interactions, producing a denser and more stable protective layer at high temperatures, significantly improving the material's antioxidant properties compared to either oxide alone. Furthermore, this composite shell exhibits excellent high-temperature self-healing capabilities. When cracks form in the shell due to thermal or mechanical stress at high temperatures, silica and alumina can self-heal the cracks through two mechanisms. Firstly, the glassy melting behavior of silica at high temperatures enables it to flow and fill the cracks. Secondly, the material exposed to the cracks reacts with ambient oxygen to form new oxides, further healing the cracks. This self-healing behavior significantly enhances the reliability of the composite shell, demonstrating excellent long-term stability in extremely high-temperature and highly oxidizing environments.

[0095] During the preparation process, through further calcination operations, the silica and alumina in the composite shell gradually transform from an amorphous state to a crystalline structure. The calcination process not only completes the crystallization of the material, but also optimizes the interfacial bonding quality of the composite shell, forming a tighter bonding area between silica and alumina. In this process, silica gradually forms a quasi-crystalline or low-order crystalline structure, while alumina is converted into the most thermodynamically stable α-alumina. This crystallization process greatly improves the mechanical strength and thermal stability of the shell, while significantly reducing the problem of interfacial stress concentration caused by thermal expansion mismatch. In addition, during the calcination stage, the pores of the composite shell gradually close and densify, further enhancing the material's antioxidant capacity and structural integrity.

[0096] The present invention constructs a functionalized metal cluster network through the synergistic effect of ammonium molybdate, ammonium tungstate, and pyridine. By utilizing molecular regulation and complexation in chemical reactions, a polymetallic oxygen cluster structure with excellent chemical stability is formed, providing the material system with unique electrical conductivity, thermal conductivity, and high-temperature performance. In an acidic environment, molybdate and tungstate ions assemble through a condensation reaction to form a polymetallic oxygen cluster with a complex structure. Its structural characteristics are a highly ordered arrangement of metal-oxygen bonds and a polynuclear metal center bridged by oxygen atoms. This condensation reaction can achieve structural control of the polymetallic oxygen cluster at the molecular level by adjusting the pH value and reaction concentration, resulting in a stable oxygen cluster precursor. Pyridine acts as a complexing agent in the reaction system, and the lone pair electrons on its nitrogen atom can form coordination bonds with the metal centers in the molybdenum and tungsten oxygen clusters, significantly enhancing the stability of the polymetallic oxygen cluster structure. At the same time, the electron donor property of pyridine can also regulate the charge distribution and reactivity of the oxygen clusters through intermolecular electron rearrangement, thereby further improving its chemical stability and durability.

[0097] During the subsequent high-temperature heat treatment, the polyoxometallic cluster precursor decomposes in a nitrogen atmosphere and gradually transforms into molybdenum and tungsten metal oxides. This process is accompanied by the release of ammonia and water molecules and the structural reorganization of the metal oxometallic clusters, ultimately forming a network of metal clusters. The formation of this cluster network relies on the self-assembly behavior of molybdenum and tungsten oxides at high temperatures. It is characterized by three-dimensional cross-linking between clusters via metal-oxygen bridges, forming a highly interconnected network structure. This network of metal clusters exhibits unique physicochemical properties at multiple scales. First, the high electron density and excellent electrical conductivity of the molybdenum and tungsten elements in the clusters significantly enhance the electrical conductivity of the overall network. Second, the high melting points and chemical inertness of molybdenum and tungsten oxides impart excellent thermal stability and oxidation resistance to the metal cluster network, enabling it to maintain structural and functional integrity even in extremely high-temperature environments. Furthermore, this network structure exhibits high thermal conductivity, effectively conducting heat and reducing local thermal stresses in the coating at high temperatures, thereby improving the coating's resistance to thermal shock.

[0098] The introduction of metal cluster networks provides key support for the multi-dimensional improvement of coating performance. In the coating system, these network structures significantly improve the overall charge conduction performance through their high conductivity, making the coating have better conductivity and resistance to electrochemical corrosion in the electrochemical environment. At the same time, the high thermal conductivity of the cluster network can effectively improve the thermal conductivity of the coating, reduce the problem of local temperature rise caused by heat accumulation in high-temperature environments, and thus improve the high-temperature stability of the coating. In addition, due to the chemical inertness and excellent antioxidant properties of the metal cluster network, the coating exhibits excellent corrosion resistance in an oxidizing atmosphere. This multifunctional property enables the introduction of functionalized metal cluster networks in the coating to not only improve the mechanical properties and thermal stability of the coating, but also significantly extend the service life of the coating in extreme environments.

[0099] The present invention improves the crack resistance and oxidation resistance of the coating by introducing intercalation-modified montmorillonite. Montmorillonite is a typical layered silicate mineral, whose structure is formed by a lamellar composite structure of silicon-containing tetrahedral layers and aluminum- or magnesium-containing octahedral layers shared by oxygen atoms. The layers are bonded by van der Waals forces, and the interlayers contain exchangeable cations and a small amount of water molecules. The unique layered structure of montmorillonite gives it good intercalation properties and a large specific surface area, and further exfoliation and expansion of the interlayer spacing through external forces can significantly expose more active sites, thereby providing favorable conditions for subsequent ion exchange and chemical reactions.

[0100] In the present invention, montmorillonite is pretreated by ultrasonic exfoliation, and the mechanical vibration of ultrasound is used to effectively overcome the van der Waals forces between the layers, increase the interlayer spacing of the montmorillonite, and form a more uniformly dispersed nanosheet structure. This process not only significantly increases the exposure of the active sites of montmorillonite, but also creates conditions for the introduction of active substances such as ammonium metavanadate and cerium nitrate. In the subsequent ion exchange process, the vanadium ions and cerium ions in the ammonium metavanadate and cerium nitrate are embedded in the interlayer structure of montmorillonite through ion exchange, replacing the original cations between the layers. In this process, the intercalation of vanadium and cerium not only changes the interlayer charge distribution of montmorillonite, but also further stabilizes the interlayer structure by forming new interlayer chemical bonds, while giving the montmorillonite interlayer additional functional properties.

[0101] Under high pressure and high temperature conditions, the vanadium and cerium ions embedded in the interlayers further react with the interlayer hydroxyl groups and silicon-oxygen bridge bonds (Si-O-Si) of montmorillonite to form a stronger chemical bond. This process is accompanied by further reorganization and densification of the intercalation structure, which ultimately significantly enhances the interlayer bonding force, thereby improving the structural stability of the intercalated montmorillonite. Subsequently, through high-temperature calcination treatment, the intercalation structure of montmorillonite is further fixed, and the embedded vanadium and cerium ions are partially oxidized during the calcination process to form stable vanadium oxide and cerium oxide nanoparticles. These metal oxides all have excellent antioxidant properties and can form a dense protective layer at high temperatures, thereby providing additional antioxidant protection for the coating.

[0102] The layered structure of intercalated montmorillonite plays a particularly critical role in the coating. First, the lamellar structure of montmorillonite can form a "brick wall" arrangement in the coating, effectively preventing the propagation of cracks through a mechanical barrier effect. When external stress triggers cracks, the crack path will be blocked and deflected by the lamellar structure, thereby significantly improving the crack resistance of the coating and delaying the crack propagation process. Secondly, the embedded vanadium ions and cerium ions and the oxides they form further enhance the oxidation resistance of the coating. Vanadium oxide can form a protective oxide film at high temperatures, effectively preventing the intrusion of oxygen or other corrosive gases; and cerium oxide, due to its high redox activity and oxygen storage capacity, can capture and neutralize oxidizing species on the coating surface, thereby further improving the stability of the coating in high-temperature oxidizing environments.

[0103] The present invention effectively improves the comprehensive performance of the coating material in a high-temperature environment by introducing a functional composite structure of boron nitride-coated vanadium carbide, including multi-dimensional optimization of antioxidant capacity, high-temperature lubrication performance, and mechanical and conductive properties. During the preparation process, vanadium carbide is first prepared by a high-temperature carbon thermal reduction method using vanadium trichloride and glucose as raw materials. In the reaction system, glucose, as a carbon source, decomposes and releases carbon at high temperature, and simultaneously undergoes a reduction reaction with vanadium trichloride to generate vanadium carbide. This process not only utilizes the thermal decomposition characteristics of glucose to provide highly active carbon, but also effectively controls the generation morphology and particle structure of vanadium carbide through the carbon thermal reduction reaction. The vanadium carbide finally prepared is a material with high hardness, high melting point and excellent conductive properties. Its chemical stability and electrical properties make it an ideal choice for functional fillers in coatings. In the coating, the high hardness of vanadium carbide can significantly improve the wear resistance of the coating, and its good electrical conductivity can also give the coating excellent electrical properties, meeting the needs in high-temperature conductive applications.

[0104] On the basis of preparing vanadium carbide, the present invention further realizes the coating of boron nitride through high-temperature reaction. Boron nitride is prepared with boric acid and urea as raw materials. First, complex decomposition and reaction occur at high temperature to generate a boron nitride precursor. Boric acid decomposes at high temperature to generate boron oxide intermediates, while urea releases ammonia and cyanic acid during the thermal decomposition process. These gaseous products provide a nitrogen source for the formation of boron nitride. Under high temperature conditions, these intermediates further react to generate hexagonal boron nitride, which has a layered structure similar to graphite and exhibits excellent chemical inertness and thermal stability. Subsequently, boron nitride is uniformly coated on the surface of vanadium carbide particles through atomization spray technology. The application of atomization spray technology can significantly improve the coating uniformity of boron nitride, while avoiding the agglomeration phenomenon that may be caused by traditional coating methods, thereby ensuring that a dense boron nitride protective layer can be formed on the surface of each vanadium carbide particle.

[0105] The vanadium carbide particles coated with boron nitride showed significant performance improvements. First, the boron nitride layer provides excellent anti-oxidation protection for vanadium carbide. In a high-temperature oxidizing environment, the exposed vanadium carbide surface easily reacts with oxygen to form vanadium oxide, which significantly reduces the mechanical properties and electrical conductivity of the material. The coated boron nitride layer, due to its high-temperature chemical inertness and low oxygen diffusivity, can effectively prevent direct contact between oxygen and vanadium carbide, thereby significantly improving the anti-oxidation performance of the composite particles in a high-temperature environment. Secondly, boron nitride itself has excellent high-temperature lubrication properties, which is due to the weak van der Waals forces between layers in its layered structure, making it easy to slip. This characteristic enables vanadium carbide particles coated with boron nitride to reduce the friction coefficient of the coating under high-temperature working conditions, thereby reducing wear and thermal stress damage. In addition, the high thermal conductivity of boron nitride can also enhance the overall thermal management capabilities of the composite particles, further improving the stability of the coating in a high-temperature environment.

[0106] At the same time, there is a synergistic enhancement effect in the system. In terms of antioxidant performance, boron nitride-coated vanadium carbide provides excellent antioxidant protection, in which the inert protective layer of boron nitride prevents the intrusion of oxygen, and the vanadium carbide itself can form stable vanadium oxide at high temperatures to further enhance the antioxidant capacity. At the same time, the layered structure of intercalated montmorillonite effectively blocks the diffusion path of oxygen through a mechanical barrier effect, and the vanadium and cerium ions embedded in montmorillonite can generate a stable oxide film through oxidation reaction at high temperatures, thereby providing secondary antioxidant protection for the interior of the coating. The interaction between multiple fillers forms a multi-level antioxidant protection mechanism, which greatly improves the long-term stability of the coating in a high-temperature oxidizing environment.

[0107] In terms of thermal conductivity: The high electrical and thermal conductivity of vanadium carbide enables rapid heat transfer within the coating, reducing localized heat accumulation. The high thermal conductivity of boron nitride further enhances the uniform distribution of heat within the coating, synergistically alleviating the problem of thermal stress concentration. Furthermore, the high thermal conductivity of the metal cluster network and the interlayer filling effect enhance the thermal conductivity of the coating at the microscale, thereby optimizing the thermal management of the entire coating.

[0108] In terms of interfacial stability, the lubricating properties and flexible layered structure of boron nitride mitigate interfacial stress caused by differences in thermal expansion coefficients at the interface, reducing the risk of delamination and cracking of the coating at high temperatures. The layered structure of intercalated montmorillonite disperses thermal and mechanical stresses through a "brick wall effect," further enhancing the coating's crack resistance.

[0109] In terms of high-temperature performance: intercalated montmorillonite maintains the integrity of its layered structure at high temperatures, providing fundamental thermal stability. Boron nitride-coated vanadium carbide particles further enhance the coating's high-temperature stability through the inert protection of boron nitride and the high melting point of vanadium carbide. Molybdenum and tungsten oxides within the metal cluster network form a dense oxide film at high temperatures, further enhancing the coating's resistance to high-temperature oxidation. The synergistic protective capabilities of these multiple components under high-temperature conditions significantly extend the coating's service life in extreme environments.

[0110] In terms of mechanical properties: the high hardness of vanadium carbide and the mechanical strength of the metallic cluster network provide the coating's fundamental wear resistance, while the lubricating properties of boron nitride reduce the coefficient of friction, minimizing friction-induced wear on the coating surface. This combination of properties ensures the coating exhibits excellent durability in high-temperature friction environments. The intercalated montmorillonite's layered structure inhibits crack propagation through a "brick wall effect," while the boron nitride's flexible layered structure buffers stress concentrations at crack tips. This synergistic effect between the different components gives the coating enhanced crack resistance and toughness in mechanical and thermal shock environments.

[0111] Compared with the prior art, the present invention has the following beneficial effects:

[0112] The ternary core material is composed of titanium carbide, zirconium boride, and silicon nitride: titanium carbide provides high hardness, excellent thermal conductivity, and oxidation resistance; zirconium boride forms a zirconium oxide protective layer through surface oxidation, which significantly enhances oxidation resistance and has a high melting point and low density; silicon nitride, due to its high toughness, thermal shock resistance, and low density, exhibits excellent thermal stability under conditions of rapid temperature changes. Through high-temperature sintering and surface modification technology, the three form a high-density, strongly bonded core material, ensuring the structural integrity and functional performance of the coating;

[0113] The silica-alumina composite shell, prepared using a sol-gel method, combines the chemical inertness of silica with the high thermal stability of alumina. The two form a synergistic antioxidant mechanism at the interface, generating a dense protective layer at high temperatures that effectively blocks oxygen and corrosive gases. Furthermore, the shell achieves crack self-healing through glassy melting behavior and oxidation reactions at high temperatures, thereby extending the coating's service life and conserving resources.

[0114] Through the synergistic effect of ammonium molybdate, ammonium tungstate, and pyridine, a stable polymetallic oxygen cluster network is constructed. After high-temperature treatment, molybdenum oxide and tungsten oxide metal clusters are generated. These metal clusters have a highly connected three-dimensional network structure, exhibiting excellent electrical and thermal conductivity and oxidation resistance. At the same time, their thermal stability and chemical inertness further enhance the coating's resistance to thermal shock and corrosion in high-temperature environments.

[0115] Through ultrasonic exfoliation and ion exchange, the active ions from ammonium metavanadate and cerium nitrate are embedded in the interlayers of montmorillonite, forming an intercalated structure with excellent crack resistance. The montmorillonite layered structure acts as a mechanical barrier to prevent crack propagation, and the embedded vanadium and cerium ions form stable oxides at high temperatures, further enhancing the coating's antioxidant properties.

[0116] With vanadium carbide as the core, the boron nitride coating is evenly distributed on the particle surface through atomization spray technology, significantly improving the high-temperature oxidation resistance and lubricity of the composite particles. Boron nitride's chemical inertness and low oxygen diffusivity effectively prevent oxidation reactions, while its layered structure imparts high-temperature lubricity to the material, reducing friction and wear.

[0117] This system significantly improves coating performance through the synergistic effect of multiple components. In terms of oxidation resistance, boron nitride-coated vanadium carbide and intercalated montmorillonite jointly construct a multi-level antioxidant barrier; in terms of thermal conductivity, vanadium carbide, boron nitride, and the metal cluster network synergistically optimize heat conduction and thermal management; in terms of interfacial stability, the lubricity of boron nitride and the "brick wall effect" of intercalated montmorillonite disperse stress and reduce interfacial cracking; in terms of high-temperature performance, multiple components synergistically enhance thermal stability and oxidation resistance; in terms of mechanical properties, the hardness of vanadium carbide, the lubricity of boron nitride, and the crack resistance of montmorillonite jointly enhance wear resistance and toughness. These synergistic effects give the coating excellent high-temperature stability and comprehensive performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0118] Figure 1 This is a flow chart of a method for preparing a polysilazane-based green special refractory ceramic coating provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0119] The technical solutions of the present invention are described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be understood as limiting the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments described herein.

[0120] The chemical reagents used in the examples and comparative examples of the present invention are all commercially available products without further purification or treatment.

[0121] Example 1

[0122] This embodiment provides a polysilazane-based green special refractory ceramic coating and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

[0123] S1: Titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol with oleic acid, then ball-milled, separated, dried, and sintered at high temperature to obtain a ternary core;

[0124] Specifically, S1: titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol in a molar ratio of 0.9:1.1:1.0, wherein the total solid content of titanium carbide, zirconium boride, and silicon nitride in the anhydrous ethanol is 18 wt.%, oleic acid is added to obtain a solution, wherein the mass fraction of oleic acid in the solution is 0.3 wt.%, the mixture is ball-milled in a silicon nitride ball mill, centrifuged, washed, and dried to obtain a mixture; the mixture is sintered under a nitrogen atmosphere at a temperature of 1620° C., a pressure of 35 MPa, and a time of 10 min, and naturally cooled to room temperature and then ground to obtain a ternary core;

[0125] S2: a mixed solution of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and aluminum nitrate is mixed and reacted with an anhydrous ethanol dispersion of the ternary core, followed by aging, separation, drying, and calcination to obtain a ternary core@self-healing oxide composite material;

[0126] Specifically, S2: mixing tetraethyl orthosilicate with anhydrous ethanol and deionized water to obtain a mixed solution A, wherein the molar ratio of tetraethyl orthosilicate to anhydrous ethanol is 1:3.8, and the molar ratio of tetraethyl orthosilicate to deionized water is 1:2.5, preparing a 1M aluminum nitrate solution, mixing it with the mixed solution A to obtain a mixed solution, wherein the molar ratio of tetraethyl orthosilicate to aluminum nitrate is 2.7:1, ultrasonically dispersing the ternary core in anhydrous ethanol and then adding the mixed solution dropwise to obtain a reaction solution B, wherein (the mass ratio of the ternary core to anhydrous ethanol is 1:96, the dropping speed of the mixed solution is 1.6 mL / min, and the mass ratio of the ternary core to tetraethyl orthosilicate is 1:12, stirring at 54°C for 3.8h, aging at room temperature for 11h, filtering, washing, and drying to obtain a pretreated material, which is calcined at 780°C for 2.6h in a nitrogen / air atmosphere to obtain a ternary core@self-healing oxide composite material;

[0127] S3: ammonium molybdate and ammonium tungstate are mixed with pyridine in deionized water, the pH is adjusted, and then reacted, separated, dried, and pyrolyzed to obtain a functionalized metal cluster network.

[0128] Specifically, S3: ammonium molybdate and ammonium tungstate are dissolved in deionized water at a molar ratio of 1.7:1, wherein the concentration of ammonium tungstate is 0.18M, ​​pyridine is added, wherein the molar ratio of ammonium molybdate to pyridine is 1:2.5, and the pH is adjusted to 6 with 1.8M nitric acid to obtain a reaction solution C, which is stirred at 67°C for 5.8h, filtered, washed, and pre-dried at 76°C for 10h to obtain a crude product, which is pyrolyzed under a nitrogen atmosphere to obtain a functionalized metal cluster network, wherein the pyrolysis temperature is 490°C and the time is 2.4h;

[0129] S4: After ultrasonic exfoliation of the montmorillonite, the montmorillonite is reacted with a mixed solution of ammonium metavanadate and cerium nitrate, and the intercalated modified montmorillonite is obtained by separation, drying and calcination;

[0130] Specifically, S4: ultrasonically exfoliate the montmorillonite for later use; prepare a 0.105M ammonium metavanadate solution and a 0.09M cerium nitrate solution, mix the ammonium metavanadate solution and the cerium nitrate solution, add the exfoliated montmorillonite, and ultrasonically obtain a reaction solution D, wherein the molar ratio of ammonium metavanadate to cerium nitrate is 1:1.6, and the mass ratio of montmorillonite to the total mass of ammonium metavanadate and cerium nitrate is 8.8:1, and the reaction solution is transferred to a high-pressure reactor for hydrothermal reaction at 180°C for 24h, centrifuged, washed, freeze-dried, and then calcined in a nitrogen / air atmosphere to obtain intercalated modified montmorillonite, wherein the calcination temperature is 690°C and the time is 1.9h;

[0131] S5: reacting vanadium trichloride with glucose in anhydrous ethanol under high pressure, and obtaining vanadium carbide through separation, drying and heat treatment;

[0132] Specifically, S5: Dissolving vanadium trichloride in anhydrous ethanol at a concentration of 0.17 M under a nitrogen atmosphere, adding glucose, and stirring at 64° C. for 1.6 hours to obtain a reaction solution E, wherein the molar ratio of vanadium trichloride to glucose is 1:1.05, transferring the solution into a high-pressure reactor, reacting at 177° C. for 11 hours, and then filtering, washing, pre-drying, and heat-treating under a nitrogen atmosphere to obtain vanadium carbide, wherein the heat treatment temperature is 1050° C. and the time is 2 hours;

[0133] S6: dispersing boric acid, urea and vanadium carbide in N,N-dimethylformamide with a dispersant, and then preparing boron nitride-coated vanadium carbide through atomization and heat treatment processes;

[0134] Specifically, S6: mixing boric acid and urea in a molar ratio of 2.5:1 and dispersing them in N,N-dimethylformamide to obtain a boric acid mixture, wherein the total concentration of boric acid and urea is 1.7M, dispersing vanadium carbide in N,N-dimethylformamide and adding dispersant BYK-111 to obtain a vanadium carbide dispersion, wherein the mass ratio of vanadium carbide to N,N-dimethylformamide is 1:120, and the mass ratio of vanadium carbide to dispersant BYK-111 is 94:1, mixing the boric acid mixture and the vanadium carbide dispersion, stirring at 72°C for 3.6h, wherein the mass ratio of vanadium carbide to boric acid is 1:0.4, and then spraying through an atomizer to obtain a precursor, wherein the inlet temperature of the atomizer is 198°C and the outlet temperature is 97°C, which is heat treated at 1350°C in a nitrogen atmosphere for 2.6h to obtain boron nitride-coated vanadium carbide;

[0135] S7: Disperse polysilazane in anhydrous toluene, add a crosslinker, dispersant, catalyst and coupling agent, and then add the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalated modified montmorillonite and boron nitride-coated vanadium carbide in sequence. After dispersion and degassing, the coating is obtained, which is sprayed on the surface of the substrate and solidified to obtain a polysilazane-based green special refractory ceramic coating.

[0136] Specifically, S7: dispersing polysilazane in anhydrous toluene at a mass fraction of 28 wt.%, adding a crosslinking agent divinyldimethylsilane, a dispersant dodecyl phosphate, a catalyst dibutyltin dilaurate, and a coupling agent isopropyl titanate, and stirring evenly to form a base liquid, wherein the amount of the crosslinking agent is 2.6% by mass of the polysilazane, the amount of the dispersant is 1.6% by mass of the polysilazane, the amount of the catalyst is 0.5% by mass of the polysilazane, and the amount of the coupling agent is 1.5% by mass of the polysilazane. The ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalation modified montmorillonite, and boron nitride coated vanadium carbide were added to the base liquid respectively, stirred and dispersed, and vacuum degassed to obtain the coating, which was sprayed on the surface of the substrate and cured at 66°C for 2.3h to obtain a polysilazane-based green special refractory ceramic coating; the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalation modified montmorillonite, and boron nitride coated vanadium carbide was 60:8:5:7:10.

[0137] Example 2

[0138] This embodiment provides a polysilazane-based green special refractory ceramic coating and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

[0139] S1: Titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol with oleic acid, then ball-milled, separated, dried, and sintered at high temperature to obtain a ternary core;

[0140] Specifically, S1: titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol in a molar ratio of 0.95:1.05:1.05, wherein the total solid content of titanium carbide, zirconium boride, and silicon nitride in the anhydrous ethanol is 19wt%, oleic acid is added to obtain a solution, wherein the mass fraction of oleic acid in the solution is 0.7wt%, the solution is ball-milled in a silicon nitride ball mill, centrifuged, washed, and dried to obtain a mixture; the mixture is sintered in a nitrogen atmosphere at a temperature of 1600°C, a pressure of 45MPa, and a time of 13min, and naturally cooled to room temperature and then ground to obtain a ternary core;

[0141] S2: a mixed solution of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and aluminum nitrate is mixed and reacted with an anhydrous ethanol dispersion of the ternary core, followed by aging, separation, drying, and calcination to obtain a ternary core@self-healing oxide composite material;

[0142] Specifically, S2: mixing tetraethyl orthosilicate with anhydrous ethanol and deionized water to obtain a mixed solution A, wherein the molar ratio of tetraethyl orthosilicate to anhydrous ethanol is 1:3.4, and the molar ratio of tetraethyl orthosilicate to deionized water is 1:2.9, preparing a 2M aluminum nitrate solution, mixing it with the mixed solution A to obtain a mixed solution, wherein the molar ratio of tetraethyl orthosilicate to aluminum nitrate is 2.3:1, ultrasonically dispersing the ternary core in anhydrous ethanol and then adding the mixed solution dropwise to obtain a reaction solution B, wherein (the mass ratio of the ternary core to anhydrous ethanol is 1:94, the dropping rate of the mixed solution is 2mL / min, and the mass ratio of the ternary core to tetraethyl orthosilicate is 1:14, stirring at 58°C for 3.4h, aging at room temperature for 10.5h, filtering, washing, and drying to obtain a pretreated material, which is calcined at 790°C for 2.3h in a nitrogen / air atmosphere to obtain a ternary core@self-healing oxide composite material;

[0143] S3: ammonium molybdate and ammonium tungstate are mixed with pyridine in deionized water, the pH is adjusted, and then reacted, separated, dried, and pyrolyzed to obtain a functionalized metal cluster network.

[0144] Specifically, S3: ammonium molybdate and ammonium tungstate are dissolved in deionized water at a molar ratio of 1.2:1, wherein the concentration of ammonium tungstate is 0.12M, pyridine is added, wherein the molar ratio of ammonium molybdate to pyridine is 1:3, and the pH is adjusted to 6.8 with 1.2M nitric acid to obtain a reaction solution C, which is stirred at 68.5°C for 6 hours, filtered, washed, and pre-dried at 78°C for 12 hours to obtain a crude product, which is pyrolyzed under a nitrogen atmosphere to obtain a functionalized metal cluster network, wherein the pyrolysis temperature is 520°C and the time is 2.8 hours;

[0145] S4: After ultrasonic exfoliation of the montmorillonite, the montmorillonite is reacted with a mixed solution of ammonium metavanadate and cerium nitrate, and the intercalated modified montmorillonite is obtained by separation, drying and calcination;

[0146] Specifically, S4: ultrasonically exfoliate the montmorillonite for later use; prepare a 0.11M ammonium metavanadate solution and a 0.10M cerium nitrate solution, mix the ammonium metavanadate solution and the cerium nitrate solution, add the exfoliated montmorillonite, and ultrasonically obtain a reaction solution D, wherein the molar ratio of ammonium metavanadate to cerium nitrate is 1:1.3, and the mass ratio of montmorillonite to the total mass of ammonium metavanadate and cerium nitrate is 9:1, and transfer it into a high-pressure reactor for hydrothermal reaction at 182°C for 25h, centrifuge, wash, freeze-dry, and then calcine in a nitrogen / air atmosphere to obtain intercalated modified montmorillonite, wherein the calcination temperature is 700°C and the time is 2.1h;

[0147] S5: reacting vanadium trichloride with glucose in anhydrous ethanol under high pressure, and obtaining vanadium carbide through separation, drying and heat treatment;

[0148] Specifically, S5: Dissolving vanadium trichloride in anhydrous ethanol at a concentration of 0.2 M under a nitrogen atmosphere, adding glucose, and stirring at 67° C. for 2 h to obtain a reaction solution E, wherein the molar ratio of vanadium trichloride to glucose is 1:1.12, transferring the solution into a high-pressure reactor, reacting at 173° C. for 11.2 h, filtering, washing, pre-drying, and then heat-treating under a nitrogen atmosphere to obtain vanadium carbide, wherein the heat treatment temperature is 1080° C. and the time is 2.8 h;

[0149] S6: dispersing boric acid, urea and vanadium carbide in N,N-dimethylformamide with a dispersant, and then preparing boron nitride-coated vanadium carbide through atomization and heat treatment processes;

[0150] Specifically, S6: mixing boric acid and urea in a molar ratio of 3:1 and dispersing them in N,N-dimethylformamide to obtain a boric acid mixture, wherein the total concentration of boric acid and urea is 2M, dispersing vanadium carbide in N,N-dimethylformamide and adding dispersant BYK-111 to obtain a vanadium carbide dispersion, wherein the mass ratio of vanadium carbide to N,N-dimethylformamide is 1:150, and the mass ratio of vanadium carbide to dispersant BYK-111 is 97:1, mixing the boric acid mixture and the vanadium carbide dispersion, stirring at 75°C for 4h, wherein the mass ratio of vanadium carbide to boric acid is 1:0.45, and then spraying through an atomizer to obtain a precursor, wherein the inlet temperature of the atomizer is 193°C and the outlet temperature is 98°C, which is heat treated at 1380°C under a nitrogen atmosphere for 3h to obtain boron nitride-coated vanadium carbide;

[0151] S7: Disperse polysilazane in anhydrous toluene, add a crosslinker, dispersant, catalyst and coupling agent, and then add the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalated modified montmorillonite and boron nitride-coated vanadium carbide in sequence. After dispersion and degassing, the coating is obtained, which is sprayed on the surface of the substrate and solidified to obtain a polysilazane-based green special refractory ceramic coating.

[0152] Specifically, S7: dispersing polysilazane in anhydrous toluene at a mass fraction of 30 wt.%, adding a crosslinking agent divinyldimethylsilane, a dispersant sodium dodecylsulfonate, a catalyst dibutyltin dilaurate and a coupling agent isopropyl titanate and stirring evenly to form a base liquid, wherein the amount of the crosslinking agent is 3% by mass of the polysilazane, the amount of the dispersant is 2% by mass of the polysilazane, the amount of the catalyst is 0.2% by mass of the polysilazane, and the amount of the coupling agent is 2% by mass of the polysilazane. The ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalated modified montmorillonite, and boron nitride-coated vanadium carbide are added to the base liquid, stirred and dispersed, and vacuum degassed to obtain a coating, which is sprayed on the surface of the substrate and cured at 68°C for 2.7 hours to obtain a polysilazane-based green special refractory ceramic coating; the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalated modified montmorillonite, and boron nitride-coated vanadium carbide is 70:11:7:6:11.

[0153] Example 3

[0154] This embodiment provides a polysilazane-based green special refractory ceramic coating and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

[0155] S1: Titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol with oleic acid, then ball-milled, separated, dried, and sintered at high temperature to obtain a ternary core;

[0156] Specifically, S1: titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol in a molar ratio of 1.0:1.0:0.9, wherein the total solid content of titanium carbide, zirconium boride, and silicon nitride in the anhydrous ethanol is 15 wt.%, oleic acid is added to obtain a solution, wherein the mass fraction of oleic acid in the solution is 0.5 wt.%, the mixture is ball-milled in a silicon nitride ball mill, centrifuged, washed, and dried to obtain a mixture; the mixture is sintered in a nitrogen atmosphere at a temperature of 1550° C., a pressure of 38 MPa, and a time of 12 min, and naturally cooled to room temperature and then ground to obtain a ternary core;

[0157] S2: a mixed solution of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and aluminum nitrate is mixed and reacted with an anhydrous ethanol dispersion of the ternary core, followed by aging, separation, drying, and calcination to obtain a ternary core@self-healing oxide composite material;

[0158] Specifically, S2: mixing tetraethyl orthosilicate with anhydrous ethanol and deionized water to obtain a mixed solution A, wherein the molar ratio of tetraethyl orthosilicate to anhydrous ethanol is 1:3, and the molar ratio of tetraethyl orthosilicate to deionized water is 1:2, preparing a 1.5M aluminum nitrate solution, mixing it with the mixed solution A to obtain a mixed solution, wherein the molar ratio of tetraethyl orthosilicate to aluminum nitrate is 2:1, ultrasonically dispersing the ternary core in anhydrous ethanol and then adding the mixed solution dropwise to obtain a reaction solution B, wherein (the mass ratio of the ternary core to anhydrous ethanol is 1:90, the dropping speed of the mixed solution is 1.8mL / min, and the mass ratio of the ternary core to tetraethyl orthosilicate is 1:10, stirring at 50°C for 3h, aging at room temperature for 10h, filtering, washing, and drying to obtain a pretreated material, which is calcined at 750°C for 2h in a nitrogen / air atmosphere to obtain a ternary core@self-healing oxide composite material;

[0159] S3: ammonium molybdate and ammonium tungstate are mixed with pyridine in deionized water, the pH is adjusted, and then reacted, separated, dried, and pyrolyzed to obtain a functionalized metal cluster network.

[0160] Specifically, S3: ammonium molybdate and ammonium tungstate are dissolved in deionized water at a molar ratio of 1:1, wherein the concentration of ammonium tungstate is 0.1M, pyridine is added, wherein the molar ratio of ammonium molybdate to pyridine is 1:2, and the pH is adjusted to 6.4 with 1M nitric acid to obtain a reaction solution C, which is stirred at 65°C for 5 hours, filtered, washed, and pre-dried at 70°C for 11 hours to obtain a crude product, which is pyrolyzed under a nitrogen atmosphere to obtain a functionalized metal cluster network, wherein the pyrolysis temperature is 450°C and the time is 2 hours;

[0161] S4: After ultrasonic exfoliation of the montmorillonite, the montmorillonite is reacted with a mixed solution of ammonium metavanadate and cerium nitrate, and the intercalated modified montmorillonite is obtained by separation, drying and calcination;

[0162] Specifically, S4: ultrasonically exfoliate the montmorillonite for later use; prepare a 0.1M ammonium metavanadate solution and a 0.08M cerium nitrate solution, mix the ammonium metavanadate solution and the cerium nitrate solution, add the exfoliated montmorillonite, and ultrasonically obtain a reaction solution D, wherein the molar ratio of ammonium metavanadate to cerium nitrate is 1:1, and the mass ratio of montmorillonite to the total mass of ammonium metavanadate and cerium nitrate is 8:1, and the reaction solution is transferred to a high-pressure reactor for hydrothermal reaction at 175° C. for 22 hours, centrifuged, washed, freeze-dried, and then calcined in a nitrogen / air atmosphere to obtain intercalated modified montmorillonite, wherein the calcination temperature is 680° C. and the time is 1.8 hours;

[0163] S5: reacting vanadium trichloride with glucose in anhydrous ethanol under high pressure, and obtaining vanadium carbide through separation, drying and heat treatment;

[0164] Specifically, S5: dissolving vanadium trichloride in anhydrous ethanol at a concentration of 0.1 M under a nitrogen atmosphere, adding glucose, and stirring at 60° C. for 1.2 h to obtain a reaction solution E, wherein the molar ratio of vanadium trichloride to glucose is 1:1, transferring the solution into a high-pressure reactor, reacting at 170° C. for 10 h, and then filtering, washing, pre-drying, and heat-treating under a nitrogen atmosphere to obtain vanadium carbide, wherein the heat treatment temperature is 1000° C. and the time is 3 h;

[0165] S6: dispersing boric acid, urea and vanadium carbide in N,N-dimethylformamide with a dispersant, and then preparing boron nitride-coated vanadium carbide through atomization and heat treatment processes;

[0166] Specifically, S6: mixing boric acid and urea in a molar ratio of 2:1 and dispersing them in N,N-dimethylformamide to obtain a boric acid mixture, wherein the total concentration of boric acid and urea is 1M, dispersing vanadium carbide in N,N-dimethylformamide and adding dispersant BYK-111 to obtain a vanadium carbide dispersion, wherein the mass ratio of vanadium carbide to N,N-dimethylformamide is 1:100, and the mass ratio of vanadium carbide to dispersant BYK-111 is 90:1, mixing the boric acid mixture and the vanadium carbide dispersion, stirring at 70°C for 3h, wherein the mass ratio of vanadium carbide to boric acid is 1:0.3, and then spraying through an atomizer to obtain a precursor, wherein the inlet temperature of the atomizer is 190°C and the outlet temperature is 95°C, which is heat treated at 1300°C in a nitrogen atmosphere for 2h to obtain boron nitride-coated vanadium carbide;

[0167] S7: Disperse polysilazane in anhydrous toluene, add a crosslinker, dispersant, catalyst and coupling agent, and then add the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalated modified montmorillonite and boron nitride-coated vanadium carbide in sequence. After dispersion and degassing, the coating is obtained, which is sprayed on the surface of the substrate and solidified to obtain a polysilazane-based green special refractory ceramic coating.

[0168] Specifically, S7: dispersing polysilazane in anhydrous toluene at a mass fraction of 25 wt.%, adding a crosslinking agent, divinyldimethylsilane, a dispersant, sodium dodecylsulfonate, a catalyst, dibutyltin dilaurate, and a coupling agent, isopropyl titanate, and stirring to form a base liquid, wherein the amount of the crosslinking agent is 2% by mass of the polysilazane, the amount of the dispersant is 1% by mass of the polysilazane, the amount of the catalyst is 0.3% by mass of the polysilazane, the amount of the coupling agent is 1% by mass of the polysilazane, and the separation is carried out. The ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalation modified montmorillonite, and boron nitride coated vanadium carbide are added to the base liquid, stirred and dispersed, and vacuum degassed to obtain a coating, which is sprayed on the surface of the substrate and cured at 60°C for 2h to obtain a polysilazane-based green special refractory ceramic coating; the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalation modified montmorillonite, and boron nitride coated vanadium carbide is 68:10:6:5:7.

[0169] Example 4

[0170] This embodiment provides a polysilazane-based green special refractory ceramic coating and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

[0171] S1: Titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol with oleic acid, then ball-milled, separated, dried, and sintered at high temperature to obtain a ternary core;

[0172] Specifically, S1: titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol in a molar ratio of 1.1:0.9:1.1, wherein the total solid content of titanium carbide, zirconium boride, and silicon nitride in the anhydrous ethanol is 20wt%, oleic acid is added to obtain a solution, wherein the mass fraction of oleic acid in the solution is 0.4wt%, the solution is ball-milled in a silicon nitride ball mill, centrifuged, washed, and dried to obtain a mixture; the mixture is sintered in a nitrogen atmosphere at a temperature of 1650°C, a pressure of 40MPa, and a time of 15min, and naturally cooled to room temperature and then ground to obtain a ternary core;

[0173] S2: a mixed solution of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and aluminum nitrate is mixed and reacted with an anhydrous ethanol dispersion of the ternary core, followed by aging, separation, drying, and calcination to obtain a ternary core@self-healing oxide composite material;

[0174] Specifically, S2: mixing tetraethyl orthosilicate with anhydrous ethanol and deionized water to obtain a mixed solution A, wherein the molar ratio of tetraethyl orthosilicate to anhydrous ethanol is 1:4, and the molar ratio of tetraethyl orthosilicate to deionized water is 1:3, preparing a 1.6M aluminum nitrate solution, mixing it with the mixed solution A to obtain a mixed solution, wherein the molar ratio of tetraethyl orthosilicate to aluminum nitrate is 3:1, ultrasonically dispersing the ternary core in anhydrous ethanol and then adding the mixed solution dropwise to obtain a reaction solution B, wherein (the mass ratio of the ternary core to anhydrous ethanol is 1:100, the dropping speed of the mixed solution is 2 mL / min, and the mass ratio of the ternary core to tetraethyl orthosilicate is 1:15, stirring at 60°C for 4h, aging at room temperature for 12h, filtering, washing, and drying to obtain a pretreated material, which is calcined at 800°C for 3h in a nitrogen / air atmosphere to obtain a ternary core@self-healing oxide composite material;

[0175] S3: ammonium molybdate and ammonium tungstate are mixed with pyridine in deionized water, the pH is adjusted, and then reacted, separated, dried, and pyrolyzed to obtain a functionalized metal cluster network.

[0176] Specifically, S3: ammonium molybdate and ammonium tungstate are dissolved in deionized water at a molar ratio of 2:1, wherein the concentration of ammonium tungstate is 0.2M, pyridine is added, wherein the molar ratio of ammonium molybdate to pyridine is 1:2.8, and the pH is adjusted to 7 with 2M nitric acid to obtain a reaction solution C, which is stirred at 70°C for 5.6 hours, filtered, washed, and pre-dried at 80°C for 11.2 hours to obtain a crude product, which is pyrolyzed under a nitrogen atmosphere to obtain a functionalized metal cluster network, wherein the pyrolysis temperature is 550°C and the time is 3 hours;

[0177] S4: After ultrasonic exfoliation of the montmorillonite, the montmorillonite is reacted with a mixed solution of ammonium metavanadate and cerium nitrate, and the intercalated modified montmorillonite is obtained by separation, drying and calcination;

[0178] Specifically, S4: ultrasonically exfoliate the montmorillonite for later use; prepare a 0.12M ammonium metavanadate solution and a 0.12M cerium nitrate solution, mix the ammonium metavanadate solution and the cerium nitrate solution, add the exfoliated montmorillonite, and mix with ultrasound to obtain a reaction solution D, wherein the molar ratio of ammonium metavanadate to cerium nitrate is 1:2, and the mass ratio of montmorillonite to the total mass of ammonium metavanadate and cerium nitrate is 10:1, and transfer it into a high-pressure reactor for hydrothermal reaction at 185° C. for 26 hours, centrifuge, wash, freeze-dry, and then calcine in a nitrogen / air atmosphere to obtain intercalated modified montmorillonite, wherein the calcination temperature is 720° C. and the time is 2.2 hours;

[0179] S5: reacting vanadium trichloride with glucose in anhydrous ethanol under high pressure, and obtaining vanadium carbide through separation, drying and heat treatment;

[0180] Specifically, S5: dissolving vanadium trichloride in anhydrous ethanol at a concentration of 0.12 M under a nitrogen atmosphere, adding glucose, and stirring at 70° C. for 1 hour to obtain a reaction solution E, wherein the molar ratio of vanadium trichloride to glucose is 1:1.2, transferring the solution into a high-pressure reactor, reacting at 180° C. for 12 hours, and then filtering, washing, pre-drying, and heat-treating under a nitrogen atmosphere to obtain vanadium carbide, wherein the heat treatment temperature is 1100° C. and the time is 2.3 hours;

[0181] S6: dispersing boric acid, urea and vanadium carbide in N,N-dimethylformamide with a dispersant, and then preparing boron nitride-coated vanadium carbide through atomization and heat treatment processes;

[0182] Specifically, S6: mixing boric acid and urea in a molar ratio of 2.3:1 and dispersing them in N,N-dimethylformamide to obtain a boric acid mixture, wherein the total concentration of boric acid and urea is 1.2M, dispersing vanadium carbide in N,N-dimethylformamide and adding dispersant BYK-111 to obtain a vanadium carbide dispersion, wherein the mass ratio of vanadium carbide to N,N-dimethylformamide is 1:140, and the mass ratio of vanadium carbide to dispersant BYK-111 is 100:1, mixing the boric acid mixture and the vanadium carbide dispersion and stirring at 73°C for 3.4h, wherein the mass ratio of vanadium carbide to boric acid is 1:0.5, and then spraying through an atomizer to obtain a precursor, wherein the inlet temperature of the atomizer is 200°C and the outlet temperature is 100°C, which is heat treated at 1400°C for 2.3h in a nitrogen atmosphere to obtain boron nitride-coated vanadium carbide;

[0183] S7: Disperse polysilazane in anhydrous toluene, add a crosslinker, dispersant, catalyst and coupling agent, and then add the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalated modified montmorillonite and boron nitride-coated vanadium carbide in sequence. After dispersion and degassing, the coating is obtained, which is sprayed on the surface of the substrate and solidified to obtain a polysilazane-based green special refractory ceramic coating.

[0184] Specifically, S7: dispersing polysilazane in anhydrous toluene at a mass fraction of 35 wt.%, adding a crosslinking agent divinyldimethylsilane and a dispersant dodecyl phosphate, a catalyst dibutyltin dilaurate and a coupling agent isopropyl titanate, and stirring evenly to form a base liquid, wherein the amount of the crosslinking agent is 2.3% by mass of the polysilazane, the amount of the dispersant is 1.8% by mass of the polysilazane, the amount of the catalyst is 0.4% by mass of the polysilazane, and the amount of the coupling agent is 1.7% by mass of the polysilazane. The ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalation modified montmorillonite and boron nitride coated vanadium carbide were added to the base liquid respectively, stirred and dispersed, and vacuum degassed to obtain the coating, which was sprayed on the surface of the substrate and cured at 70°C for 3h to obtain a polysilazane-based green special refractory ceramic coating; the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalation modified montmorillonite and boron nitride coated vanadium carbide was 75:12:8:8:12.

[0185] Comparative Example 1

[0186] This comparative example provides a polysilazane-based green special refractory ceramic coating, which differs from Example 1 in that, in S7, the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, the functionalized metal cluster network, the intercalated modified montmorillonite, and the boron nitride-coated vanadium carbide is 60:20:5:7:10, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0187] Comparative Example 2

[0188] This comparative example provides a polysilazane-based green special refractory ceramic coating, which differs from Example 1 in that, in S7, the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, the functionalized metal cluster network, the intercalated modified montmorillonite, and the boron nitride-coated vanadium carbide is 60:2:5:7:10, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0189] Comparative Example 3

[0190] This comparative example provides a polysilazane-based green special refractory ceramic coating, which differs from Example 1 in that, in S7, the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, the functionalized metal cluster network, the intercalated modified montmorillonite, and the boron nitride-coated vanadium carbide is 60:8:10:7:10, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0191] Comparative Example 4

[0192] This comparative example provides a polysilazane-based green special refractory ceramic coating, which differs from Example 1 in that, in S7, the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, the functionalized metal cluster network, the intercalated modified montmorillonite, and the boron nitride-coated vanadium carbide is 60:8:1:7:10, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0193] Comparative Example 5

[0194] This comparative example provides a polysilazane-based green special refractory ceramic coating, which differs from Example 1 in that, in S7, the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, the functionalized metal cluster network, the intercalated modified montmorillonite, and the boron nitride-coated vanadium carbide is 60:8:5:10:10, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0195] Comparative Example 6

[0196] This comparative example provides a polysilazane-based green special refractory ceramic coating, which differs from Example 1 in that, in S7, the mass ratio of polysilazane to the ternary core@self-healing oxide composite material, the functionalized metal cluster network, the intercalated modified montmorillonite, and the boron nitride-coated vanadium carbide is 60:8:5:2:10, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0197] The performance test of the polysilazane-based green special refractory ceramic coatings of Examples 1-4 and Comparative Examples 1-6 was conducted, and the specific process is as follows:

[0198] Test the hardness of the coating according to GB / T 6739-2022;

[0199] Test the thermal shock resistance of the coating: Place the material in a 700°C oxygen high-temperature furnace for 10 minutes, take it out and place it at room temperature for 10 minutes, which is recorded as one thermal shock cycle test; record the state of the coating after 5 cycles.

[0200] The test results are shown in Table 1.

[0201] Table 1: Performance test results of polysilazane-based green special refractory ceramic coatings of Examples 1-4 and Comparative Examples 1-6

[0202]

[0203]

[0204] From the test results of Example 1 and Comparative Examples 1 and 2, it can be seen that excessive addition of the ternary core @ self-healing oxide composite material leads to an increase in the density of the coating, and at the same time produces a large difference in the thermal expansion coefficient, causing the coating to crack or peel off during the temperature shock resistance cycle. In addition, excessive addition will trigger interfacial stress concentration between the particles, resulting in overall brittleness of the coating and a decrease in hardness uniformity; the ternary core @ self-healing oxide composite material prevents the intrusion of oxygen and corrosive gases by generating a dense silica-alumina composite protective layer. Too little addition will lead to a decrease in the stability of the coating and a decrease in the hardness of the coating.

[0205] The test results of Example 1 and Comparative Examples 3 and 4 show that excessive addition of the functionalized metal cluster network can lead to cluster aggregation, resulting in uneven distribution or localized stress concentration, which weakens the overall strength and thermal shock resistance of the coating. Excessive addition can lead to uneven cluster distribution, forming stress concentration areas, and thus reducing the overall hardness uniformity. Insufficient addition can cause heat to accumulate locally in the coating, causing thermal damage. Furthermore, the metal clusters play a reinforcing role in the coating, especially at high temperatures, due to their high melting point and strong bonding strength, which increases hardness. Insufficient addition can weaken this strengthening effect, resulting in a decrease in coating hardness.

[0206] From the test results of Example 1 and Comparative Examples 5 and 6, it can be seen that the layered structure and embedded vanadium and cerium ions in the intercalated montmorillonite generate a stable oxide film at high temperature, providing antioxidant protection and preventing crack propagation through the layered structure. However, excessive addition will cause stacking and agglomeration between the layers, resulting in the formation of a weak interface inside the coating, reducing the overall bonding strength and weakening the hardness of the coating; insufficient addition will cause the coating to lack an effective crack buffer mechanism and secondary antioxidant barrier, and the hardness of the coating will be reduced.

[0207] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a polysilazane-based green special refractory ceramic coating, characterized in that: The preparation method comprises: S1: Titanium carbide, zirconium boride, and silicon nitride are dispersed in anhydrous ethanol with oleic acid, then ball-milled, separated, dried, and sintered at high temperature to obtain a ternary core; S2: a mixed solution of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and aluminum nitrate is mixed and reacted with an anhydrous ethanol dispersion of the ternary core, followed by aging, separation, drying, and calcination to obtain a ternary core@self-healing oxide composite material; S3: ammonium molybdate and ammonium tungstate are mixed with pyridine in deionized water, the pH is adjusted, and then reacted, separated, dried, and pyrolyzed to obtain a functionalized metal cluster network. S4: preparing and mixing an ammonium metavanadate solution and a cerium nitrate solution; ultrasonically exfoliating the montmorillonite, reacting the solution with the ammonium metavanadate and cerium nitrate solution, separating, drying, and calcining to obtain intercalated modified montmorillonite; S5: reacting vanadium trichloride with glucose in anhydrous ethanol under high pressure, and obtaining vanadium carbide through separation, drying and heat treatment; S6: dispersing boric acid, urea and vanadium carbide in N,N-dimethylformamide with a dispersant, and then preparing boron nitride-coated vanadium carbide through atomization and heat treatment processes; S7: Disperse polysilazane in anhydrous toluene, add a crosslinker, dispersant, catalyst and coupling agent, and then add the ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalated modified montmorillonite and boron nitride-coated vanadium carbide in sequence. After dispersion and degassing, the coating is obtained, which is sprayed on the surface of the substrate and cured to obtain a polysilazane-based green special refractory ceramic coating.

2. The method for preparing a polysilazane-based green special refractory ceramic coating according to claim 1, characterized in that: In S7: The crosslinking agent is divinyldimethylsilane, and the amount of the crosslinking agent is 2-3% of the mass of the polysilazane; The dispersant is any one of sodium lauryl sulfonate and lauryl phosphate, or a combination of the two; The dosage of the dispersant is 1-2% of the mass of the polysilazane; The catalyst is dibutyltin dilaurate, and the amount of the catalyst is 0.2-0.5% of the mass of the polysilazane; The coupling agent is isopropyl titanate, and the amount of the coupling agent is 1-2% of the mass of the polysilazane.

3. The method for preparing a polysilazane-based green special refractory ceramic coating according to claim 1, characterized in that: In S7: the mass ratio of the polysilazane, ternary core@self-healing oxide composite material, functionalized metal cluster network, intercalation modified montmorillonite, and boron nitride-coated vanadium carbide is (60-75):(8-12):(5-8):(5-8):(7-12).

4. The method for preparing a polysilazane-based green special refractory ceramic coating according to claim 1, characterized in that: In S1: The molar ratio of titanium carbide, zirconium boride and silicon nitride is (0.9-1.1):(0.9-1.1):(0.9-1.1); The total solid content of the titanium carbide, zirconium boride and silicon nitride dispersed in anhydrous ethanol is 15-20wt.%; The mass fraction of the oleic acid in the solution is 0.3-0.7 wt %.

5. The method for preparing a polysilazane-based green special refractory ceramic coating according to claim 1, characterized in that: In S2: The molar ratio of the tetraethyl orthosilicate to aluminum nitrate is (2-3):1; The mass ratio of the ternary core to tetraethyl orthosilicate is 1:(10-15); The calcination temperature is 750-800°C; The calcination time is 2-3 hours.

6. The method for preparing a polysilazane-based green special refractory ceramic coating according to claim 1, characterized in that: In S3: The molar ratio of ammonium molybdate to ammonium tungstate is (1-2):1; The concentration of the ammonium tungstate is 0.1-0.2M; The molar ratio of ammonium molybdate to pyridine is 1:(2-3).

7. The method for preparing a polysilazane-based green special refractory ceramic coating according to claim 1, characterized in that: In S4: The concentration of the ammonium metavanadate solution is 0.1-0.12M; The concentration of the cerium nitrate solution is 0.08-0.12M; The molar ratio of ammonium metavanadate to cerium nitrate is 1:(1-2); The mass ratio of the mixed solution of ammonium metavanadate and cerium nitrate to montmorillonite is 1:(8-10).

8. The method for preparing a polysilazane-based green special refractory ceramic coating according to claim 1, characterized in that: In S5: The concentration of the vanadium trichloride in anhydrous ethanol is 0.1-0.2M; The molar ratio of the vanadium trichloride to glucose is 1:(1-1.2).

9. The method for preparing a polysilazane-based green special refractory ceramic coating according to claim 1, characterized in that: In S6: The molar ratio of boric acid to urea is (2-3):1; The mass ratio of the vanadium carbide to boric acid is 1:(0.3-0.5); The dispersant is BYK-111, and the mass ratio of vanadium carbide to dispersant BYK-111 is (90-100):

1.

10. A polysilazane-based green special refractory ceramic coating prepared by the preparation method according to any one of claims 1 to 9.

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