A surface coating for ceramic mould bricks, its method of manufacture and use

Abstract

The application provides a surface coating of a ceramic die brick and a preparation method and application thereof. In the direction from the ceramic die brick body to the ceramic die brick body, the surface coating comprises a boron nitride layer, a carbon layer and a silicon-carbon compound layer which are stacked in sequence. The application creates a composite coating system which can withstand high temperature environment and protect the base material through the synergistic effect of the composite coating of the boron nitride layer, the carbon layer and the silicon-carbon compound layer, while maintaining the unique performance of each material, thereby significantly improving the performance of the overall coating, improving the heat resistance, oxidation resistance and mechanical strength of the ceramic die brick, ensuring high-quality production while reducing the cost and improving the economic benefit.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ceramic mold bricks, and relates to a surface coating of a ceramic mold brick and a preparation method and application thereof. BACKGROUND

[0002] Currently, the production of HUD glass curved mirrors relies on mold bricks that can maintain stable shape and size at high temperatures (HUD is the abbreviation of English Head Up Display, which means "head-up display", also known as head-up display system). Traditional ceramic mold bricks are prone to physical and chemical performance degradation when exposed to high temperature environment for a long time, such as thermal shock cracks, surface oxidation and interface adhesion reduction. In addition, conventional single material coating cannot effectively cope with the stress concentration problem caused by thermal expansion mismatch. These mold bricks must be able to withstand continuous thermal cycles, maintain strict dimensional accuracy, and maintain their mechanical strength and chemical stability at high temperatures.

[0003] Existing ceramic mold bricks are mainly made of some ordinary refractory materials, such as alumina, silicon carbide and silicon nitride. Although these materials have certain high temperature resistance, they still have many problems at extreme temperatures, such as: (1) structural damage caused by thermal expansion mismatch: the existing ceramic mold bricks will inevitably produce thermal stress due to the inconsistency of the internal thermal expansion coefficient in repeated high temperature cycles, which will cause cracks or even breakage of the mold bricks, especially in the hole area of the mold bricks, the damage caused by thermal stress concentration is a common problem; (2) chemical reaction problem at high temperature: it is a certain phenomenon that ceramic mold bricks will chemically react with oxygen in the air under high temperature conditions, which changes the surface properties of the mold bricks and affects their service life and compatibility with glass; (3) insufficient interface adhesion: during the high temperature forming process, the interface adhesion between the mold bricks and the glass will decrease, which will directly affect the optical properties and structural integrity of the product; (4) production efficiency and cost-effectiveness problem: the production process of ceramic mold bricks is complex, such as accurate control of hole size and distribution, which not only reduces production efficiency, but also increases production cost; (5) life and durability limitation: the wear resistance and anti-degradation ability of ceramic mold bricks are limited, and they must be replaced after long-term use, which leads to production stagnation and cost increase. These problems lead to early failure of the mold bricks, increase the production cost, and affect the quality of the final product.

[0004] Therefore, the current technology has the defect that it cannot provide a stable and uniform working surface, cannot prevent chemical reactions at high temperatures, and cannot effectively control the stress caused by thermal expansion. These problems not only limit the service life of the mold brick, but also limit the manufacturing efficiency and performance of glass products. It is difficult to better solve the above problems through existing coating technologies such as simple oxidation layer or carbonization layer. The existing coating has the problem of insufficient stability in high temperature and high stress environment. Moreover, the preparation process of these coatings is often very complex, involving high energy consumption and high-cost equipment, making it difficult to achieve low-cost mass production.

[0005] Therefore, it is an urgent technical problem to develop a new ceramic mold brick surface engineering technology to provide higher performance to meet the needs of precision, durability and cost-effectiveness in the production process of high-end glass products such as HUD glass curved mirrors. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a surface coating of a ceramic mold brick and a preparation method and application thereof. The present application creates a composite coating system that can withstand high temperature environment and protect the base material through the synergistic effect of the composite coating of boron nitride layer, carbon layer and silicon-carbon compound layer, while maintaining the unique properties of each material. The performance of the overall coating is significantly improved, thereby improving the heat resistance, oxidation resistance and mechanical strength of the ceramic mold brick, ensuring high-quality production while reducing costs and improving economic benefits.

[0007] To achieve the purpose of the present application, the following technical solutions are adopted:

[0008] In a first aspect, the present application provides a surface coating of a ceramic mold brick, which includes a boron nitride layer, a carbon layer and a silicon-carbon compound layer stacked in order from the direction close to the body of the ceramic mold brick to the direction away from the body of the ceramic mold brick.

[0009] The present application provides a surface coating structure for ceramic mold bricks, which comprises a boron nitride layer, a carbon layer, and a silicon-carbon compound layer. The boron nitride layer serves as the first layer, which not only improves the thermal expansion matching but also introduces self-lubricating properties, effectively alleviating thermal stress caused by thermal expansion mismatch, especially at the interface between the ceramic mold brick and the glass substrate. In addition, the chemical inertness of boron nitride helps to protect the ceramic mold brick body from potential chemical corrosion in high-temperature environments. The carbon layer has good thermal stability and can provide additional oxidation protection. At high temperatures, the carbon layer acts as a protective barrier, preventing direct contact between the ceramic mold brick body and oxygen or other reactive gases, and also helps to alleviate interfacial stress, enhancing the integrity of the entire coating structure. The silicon-carbon compound layer exhibits extremely strong thermal stability in high-temperature environments, resisting structural changes and chemical degradation caused by extreme temperatures. Its hardness and wear resistance also help to improve the wear resistance of the surface, effectively transmitting loads and enhancing the structural integrity of the entire coating system. In some high-temperature applications, the silicon-carbon compound layer also protects other structures (such as the boron nitride layer and the carbon layer) from thermal stress and oxidation. Through the synergistic cooperation of the boron nitride layer, the carbon layer, and the silicon-carbon compound layer, as well as the layering sequence, the advantages of each layer are realized, and the heat resistance, oxidation resistance, and mechanical strength of the mold brick are significantly improved, creating a composite coating system that can withstand high-temperature environments and protect the substrate material. This system design takes into account the chemical, physical, and mechanical properties of the materials to ensure optimal performance and durability during the manufacturing process of HUD glass curved mirrors, and also improves the matching between the ceramic mold brick and the glass.

[0010] The surface coating structure provided by the present application must be synergistically combined by the boron nitride layer, the carbon layer, and the silicon-carbon compound layer to achieve stronger heat resistance, excellent oxidation resistance, and enhanced mechanical strength. The structure lacking any single layer cannot achieve such high efficiency and multifunctionality. Moreover, the layering sequence is crucial, and adjusting the layering sequence cannot achieve the best performance of each layer and the effective integration of these performances. This precise layering structure ensures the best complementarity and functional synergy between the layers, thereby achieving the expected overall performance improvement.

[0011] Preferably, the thickness of the boron nitride layer is 0.2-2 μm, such as 0.2 μm, 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 1.3 μm, 1.5 μm, 1.8 μm, or 2 μm, but is not limited to the listed values, and other unlisted values within this range are also applicable.

[0012] Preferably, the thickness of the carbon layer is 1-3 μm, such as 1 μm, 1.3 μm, 1.5 μm, 1.8 μm, 2 μm, 2.3 μm, 2.5 μm, 2.8 μm or 3 μm, etc., but not limited to the listed values, and other values not listed in the range are also applicable.

[0013] In the present application, the thickness of the carbon layer is too thin, which is not conducive to achieving sufficient thermal expansion matching and self-lubricating properties, resulting in an increase in thermal stress mismatch between the mold brick and the glass substrate in a high-temperature environment; and if the thickness is too thick, it will affect the overall thermal conductivity of the coating, resulting in a slower thermal response speed of the coating, thereby affecting the thermal stability and manufacturing efficiency of the entire mold brick.

[0014] Preferably, the thickness of the silicon-carbon compound layer is 3-5 μm, such as 3 μm, 3.3 μm, 3.5 μm, 3.8 μm, 4 μm, 4.3 μm, 4.5 μm, 4.8 μm or 5 μm, etc., but not limited to the listed values, and other values not listed in the range are also applicable.

[0015] In the present application, if the thickness of the silicon-carbon compound layer is too thin, it is difficult to achieve sufficient structural integrity and thermal stress cracking resistance; and if the thickness is too thick, the overall coating will become fragile, increasing the risk of material fracture, and resulting in uneconomical cost.

[0016] Preferably, the first interfacial layer is further included between the boron nitride layer and the carbon layer.

[0017] Preferably, the second interfacial layer is further included between the carbon layer and the silicon-carbon compound layer.

[0018] In the present application, the first interfacial layer and / or the second interfacial layer play a role in enhancing the interfacial adhesion and improving the chemical compatibility between the layers, effectively relieving the internal stress caused by the difference in thermal expansion coefficient between the materials, and ensuring the stability of the coating at high temperatures.

[0019] Preferably, the carbon layer is doped with silicon at the surface layer near the first interfacial layer, and / or the carbon layer is doped with silicon at the surface layer near the second interfacial layer.

[0020] In the present application, silicon doping is performed at two surface layers in the carbon layer (i.e., silicon doping is performed at the initial and later stages of carbon layer preparation), the first silicon doping is conducive to forming a stable carbon-based structure, while strengthening the structural transition between the boron nitride layer and the carbon layer; and the second silicon doping is conducive to ensuring the formation and optimization of the second interfacial layer; by performing non-continuous silicon doping in the carbon layer, the present application avoids excessive reaction between the carbon layer and silicon, thereby destroying the structure of the carbon layer and resulting in its inability to play a corresponding role.

[0021] Preferably, the first silicon doping has a doping amount in the carbon layer in a volume percentage of 0.01-0.1%, such as 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1%, etc., but not limited to the listed values, and other values not listed in the range are also applicable.

[0022] In the present application, if the first silicon doping has too large a doping amount, the electrical conductivity and thermal conductivity of the carbon layer will be reduced, affecting the efficiency of the thermal barrier; and if the first silicon doping has too small a doping amount, the bonding force between the carbon layer and the boron nitride layer will be affected, reducing the structural integrity, thereby affecting the mechanical stability and heat resistance of the entire coating.

[0023] Preferably, the second silicon doping has a doping amount in the carbon layer in a volume percentage of 0.1-1%, such as 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, etc., but not limited to the listed values, and other values not listed in the range are also applicable.

[0024] In the present application, if the second silicon doping has too large a doping amount, the second cross-linked interface layer will be too weak and prone to breakage under high temperature or mechanical stress; and if the doping amount is too small, the interfacial adhesion between the carbon layer and the silicon carbide layer will be affected, reducing the performance retention in high-temperature applications, especially the compatibility in the process of forming ceramic mold bricks and high-temperature glass.

[0025] In a second aspect, the present application provides a preparation method of a surface coating of a ceramic mold brick as described in the first aspect, the preparation method comprising the following steps:

[0026] Sequentially compounding a boron nitride layer, a carbon layer, and a silicon carbide layer on the surface of the ceramic mold brick body.

[0027] The preparation method provided by the present application forms a uniform and dense coating structure, which is suitable for large-scale production.

[0028] Preferably, the compounding method of the boron nitride comprises:

[0029] Depositing a boron nitride layer on the surface of the ceramic mold brick body by chemical vapor deposition method through a boron source and a nitrogen source.

[0030] Preferably, the boron source comprises a boron hydride.

[0031] Preferably, the nitrogen source comprises ammonia.

[0032] Preferably, the gas flow of the boron source is 10-50 cm 2 / min, such as 10 cm2 / min, 15 cm 2 / min, 20 cm 2 / min, 25 cm 2 / min, 30 cm 2 / min, 35 cm 2 / min, 40 cm 2 / min, 45 cm 2 / min, or 50 cm 2 / min, etc., but not only the listed values, other values within the range are also applicable.

[0033] Preferably, the gas flow of the nitrogen source is 20-100 cm 2 / min, for example 20 cm 2 / min, 30 cm 2 / min, 40 cm 2 / min, 50 cm 2 / min, 60 cm 2 / min, 70 cm 2 / min, 80 cm 2 / min, 90 cm 2 / min, or 100 cm 2 / min, etc., but not only the listed values, other values within the range are also applicable.

[0034] Preferably, the temperature of the chemical vapor deposition in the boron nitride deposition process is 900-1100°C, for example 900°C, 1000°C, or 1100°C, etc., and the time of the chemical vapor deposition is 1-3 h, for example 1 h, 2 h, or 3 h, etc., but not only the listed values, other values within the range are also applicable.

[0035] Preferably, after the boron nitride layer deposition, a first crosslinking treatment is performed on the surface of the boron nitride layer.

[0036] Preferably, the crosslinking agent of the first crosslinking treatment comprises an organic silicon crosslinking agent.

[0037] Preferably, the amount of the crosslinking agent in the first crosslinking treatment is 0.1-1 mL / cm 2 , for example 0.1 mL / cm 2 , 0.2 mL / cm 2 , 0.3 mL / cm 2 , 0.4 mL / cm 2 , 0.5 mL / cm 2 , 0.6 mL / cm 2 , 0.7 mL / cm 20.8 mL / cm 2 0.9 mL / cm 2 or 1 mL / cm 2 and so on, but not only the listed values, other values within the range are also applicable.

[0038] Preferably, the cross-linking temperature of the first cross-linking treatment is 150-300℃, such as 150℃, 175℃, 200℃, 225℃, 250℃, 275℃ or 300℃, and so on, but not only the listed values, other values within the range are also applicable.

[0039] Preferably, the cross-linking time of the first cross-linking treatment is 1-4h, such as 1h, 2h, 3h or 4h, and so on, but not only the listed values, other values within the range are also applicable.

[0040] Preferably, the composite method of the carbon layer comprises:

[0041] depositing a carbon source onto the surface of the boron nitride layer by chemical vapor deposition to obtain a carbon layer.

[0042] Preferably, during the deposition of the carbon layer, the gas flow of the carbon source is 50-200cm 2 / min, such as 50cm 2 / min, 100cm 2 / min, 150cm 2 / min or 200cm 2 / min, and so on, but not only the listed values, other values within the range are also applicable.

[0043] Preferably, during the deposition of the carbon layer, the temperature of the chemical vapor deposition is 800-1000℃, such as 800℃, 850℃, 900℃, 950℃ or 1000℃, and so on, and the time of the chemical vapor deposition is 1-2h, such as 1h or 2h, but not only the listed values, other values within the range are also applicable.

[0044] Preferably, during the deposition of the carbon layer, silicon is also doped in the deposition gas; the doping is performed in stages, with an initial doping amount of 0.01 to 0.1 vol%, such as 0.01 vol%, 0.02 vol%, 0.03 vol%, 0.04 vol%, 0.05 vol%, 0.06 vol%, 0.07 vol%, 0.08 vol%, 0.09 vol% or 0.1 vol%, and a later doping amount of 0.1 to 1 vol%, such as 0.1 vol%, 0.2 vol%, 0.3 vol%, 0.4 vol%, 0.5 vol%, 0.6 vol%, 0.7 vol%, 0.8 vol%, 0.9 vol% or 1 vol%, but not limited to the listed values, and other values not listed in the range are also applicable.

[0045] Preferably, after the deposition of the carbon layer, a second cross-linking treatment is performed on the surface of the carbon layer.

[0046] Preferably, the cross-linking agent of the second cross-linking treatment comprises an organosilicon cross-linking agent.

[0047] It should be noted that the type of organosilicon cross-linking agent in the present application is a conventional technical choice, including but not limited to methyltrichlorosilane.

[0048] Preferably, the amount of cross-linking agent used in the second cross-linking treatment is 0.1 to 1 mL / cm 2 , such as 0.1 mL / cm 2 , 0.2 mL / cm 2 , 0.3 mL / cm 2 , 0.4 mL / cm 2 , 0.5 mL / cm 2 , 0.6 mL / cm 2 , 0.7 mL / cm 2 , 0.8 mL / cm 2 , 0.9 mL / cm 2 or 1 mL / cm 2 , but not limited to the listed values, and other values not listed in the range are also applicable.

[0049] In the present application, during the first cross-linking treatment and the second cross-linking treatment, if the amount of cross-linking agent used is too much, it will affect the flexibility and overall toughness of the coating, causing the coating to be more prone to cracking or delamination under thermal cycling or mechanical stress, and if it is too little, it will cause the formation of the cross-linking interface layer to be insufficient, reducing the bonding strength of the interface and reducing the overall stability of the coating, especially in high-temperature or high-pressure applications, which can easily lead to failure of the coating.

[0050] Preferably, the cross-linking temperature of the second cross-linking treatment is 200-300℃, such as 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃ or 300℃, etc., but not limited to the listed values, and other values not listed within the range of values are also applicable.

[0051] Preferably, the cross-linking time of the second cross-linking treatment is 1-4h, such as 1h, 2h, 3h or 4h, etc., but not limited to the listed values, and other values not listed within the range of values are also applicable.

[0052] Preferably, the composite method of the silicon-carbon compound layer comprises:

[0053] The deposition of the silicon-carbon compound layer is carried out by a precursor impregnation-pyrolysis method.

[0054] The preparation method provided by the present application prepares the coating structure by a combined preparation method of chemical vapor deposition (CVD) and precursor impregnation-pyrolysis (PIP). By combining the application of CVD and PIP technologies, the advantages of each technology can be fully utilized while ensuring the uniformity and compactness of the coating. CVD provides the uniformity and high quality of the coating, while PIP allows the composite material to penetrate more deeply into the microstructure of the brick. The preparation method provided by the present application is particularly suitable for application processes that require high temperature performance and durability. By this method, it can be ensured that the coating remains stable throughout the entire service life, and its performance can be maintained even under high temperature and extreme conditions.

[0055] Preferably, after the deposition of the carbon layer, the ceramic brick is immersed in a silicon-carbon compound precursor, and pyrolysis is carried out to obtain a silicon-carbon compound layer.

[0056] Preferably, through the process of repeated impregnation and pyrolysis, the thickness and quality of the silicon-carbon compound layer can be effectively controlled.

[0057] Preferably, the pyrolysis temperature is 1000-1200℃, such as 1000℃, 1050℃, 1100℃, 1150℃ or 1200℃, etc., and the pyrolysis time is 2-4h, such as 2h, 3h or 4h, etc., but not limited to the listed values, and other values not listed within the range of values are also applicable.

[0058] As a preferred technical solution, the preparation method comprises the following steps:

[0059] The boron source and the nitrogen source are deposited on the surface of the ceramic brick body by chemical vapor deposition to obtain a boron nitride layer, and the boron nitride layer is subjected to a first cross-linking treatment at 150-300℃ for 1-4h using an organic silicon cross-linking agent in an amount of 0.1-1mL / cm 2 .

[0060] The carbon source is deposited onto the surface of the cross-linked boron nitride layer by chemical vapor deposition to obtain a carbon layer, and silicon is doped in the deposition gas during the deposition of the carbon layer; the doping is carried out in stages, the initial doping amount is 0.01 to 0.1 volume percent, and the later doping amount is 0.1 to 1 volume percent; after the carbon layer is deposited, the carbon layer is subjected to a second cross-linking treatment at 200 to 300 DEG C using an organic silicon cross-linking agent in an amount of 0.1 to 1 mL / cm 2

[0061] After the cross-linking treatment of the carbon layer is completed, the ceramic mold brick after the carbon layer is deposited is immersed in a silicon-carbon compound precursor to obtain a silicon-carbon compound layer by pyrolysis, thereby obtaining the surface coating of the ceramic mold brick.

[0062] It should be noted that the mold brick body provided by the present application is a conventional technical solution, and the structure, material and preparation process of the mold brick body for a curved mirror within the reasonable range of persons skilled in the art can be known, and the present application is applicable.

[0063] In a third aspect, the present application provides a ceramic mold brick, which comprises a ceramic mold brick body and a surface coating on the surface of the ceramic mold brick body, wherein the surface coating is as described in the first aspect.

[0064] In a fourth aspect, the present application further provides an application of the ceramic mold brick as described in the first aspect in a HUD glass curved mirror.

[0065] Compared with the prior art, the present application has the following beneficial effects:

[0066] ​The present application takes the composite layer of boron nitride layer, carbon layer and silicon-carbon compound layer stacked as the surface coating of the ceramic die brick; boron nitride as the first layer not only improves the thermal expansion matching, but also introduces the self-lubricating property, which can effectively relieve the thermal stress caused by the mismatch of thermal expansion, especially at the interface between the ceramic die brick and the glass substrate. In addition, the chemical inertness of boron nitride also helps to protect the ceramic die brick body from potential chemical corrosion in high temperature environment; the carbon layer has good thermal stability and can provide additional oxidation protection. At high temperatures, the carbon layer can act as a protective barrier to prevent direct contact between the ceramic die brick body and oxygen or other reactive gases, and can also help to relieve interface stress and enhance the integrity of the entire coating structure; the silicon-carbon compound layer exhibits extremely strong thermal stability in high temperature environment, can resist structural changes and chemical degradation caused by extreme temperatures, and the hardness and wear resistance also help to improve the wear resistance of the surface, can effectively transfer the load and enhance the structural integrity of the entire coating system. In some high temperature applications, the silicon-carbon compound layer can also protect other structures (such as boron nitride layer and carbon layer) from thermal stress and oxidation; through the synergistic cooperation of boron nitride layer, carbon layer and silicon-carbon compound layer and the stacking sequence, the advantages of each layer are exerted and synergistic effect is achieved, which significantly improves the heat resistance, oxidation resistance and mechanical strength of the die brick, and creates a composite coating system that can withstand high temperature environment and protect the base material; the design of this system takes into account the chemical, physical and mechanical properties of the material to ensure the best performance and durability during the manufacturing process of the HUD glass curved mirror, and also improves the matching between the ceramic die brick and the glass. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 The surface coating and the structure of the ceramic die brick provided for example 1 are shown in the schematic diagram.

[0068] Among them, 1-ceramic die brick body, 2-boron nitride layer, 3-carbon layer, 4-silicon-carbon compound layer. DETAILED DESCRIPTION

[0069] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations of the present application.

[0070] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the present application are intended to cover non-exclusive inclusion.

[0071] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0072] Embodiment 1

[0073] The present embodiment provides a surface coating of a ceramic die brick, as shown, along the direction close to the ceramic die brick body 1 to the direction away from the ceramic die brick body 1, the surface coating comprises boron nitride layer 2 (thickness of 2 μm), carbon layer 3 (thickness of 1 μm) and silicon-carbon compound layer 4 (thickness of 4 μm) stacked in sequence. Figure 1

[0074] The first cross-linking interface layer is further included between the boron nitride layer 2 and the carbon layer 3; the second cross-linking interface layer is further included between the carbon layer 3 and the silicon-carbon compound layer 4; the carbon layer 3 is first doped with silicon at the surface layer close to the first cross-linking interface layer (the doping amount of the first silicon doping in the carbon layer 3 is 0.1% in volume percentage); the carbon layer 3 is second doped with silicon at the surface layer close to the second cross-linking interface layer (the doping amount of the second silicon doping in the carbon layer is 0.1% in volume percentage).

[0075] The preparation method of the surface coating is as follows:

[0076] (1) Boron nitride (BN) layer deposition

[0077] Pre-treatment and pre-heating of the die brick: the pre-treated die brick (the type of the die brick is high-purity alumina ceramic) is placed in the reaction chamber of a hot-wall chemical vapor deposition (Thermal CVD) system; the hot-wall CVD system slowly heats the reaction chamber to the set deposition temperature to prevent thermal stress of the die brick; precise temperature monitoring equipment such as thermocouple is used to ensure that the temperature of the die brick is uniform during the whole pre-heating process;

[0078] Gas injection and boron nitride layer deposition: borohydride (borane: gas flow rate is 25 cm 2 / min) and ammonia gas (gas flow rate is 50 cm 2 / min) are injected into the hot-wall CVD system to start the BN layer deposition process; the deposition temperature is 1000℃, and the deposition time is 2h to obtain the boron nitride layer on the surface of the die brick body (during the deposition process, a spectrometer is used to monitor the growth and quality of the coating in real time);

[0079] Post-treatment and cooling: after the deposition is completed, the temperature of the hot-wall CVD system is gradually reduced to allow the coating to cool naturally;

[0080] ​Quality inspection: after cooling, the BN coating is visually and instrumentally inspected to ensure no defects; using precise measuring tools such as micrometer, confirm that the thickness of BN layer meets the specification requirements;

[0081] (2) Formation of the first cross-linking interface layer

[0082] The side surface of the boron nitride layer away from the body of the mold brick is subjected to a first cross-linking treatment of methyltrichlorosilane (0.5 mL / cm 2 ) at a temperature of 300°C for 3h, forming a first cross-linking interface layer on the surface of the boron nitride layer;

[0083] (3) Carbon layer deposition

[0084] Deposition of a carbon layer on the surface of the first cross-linking interface layer:

[0085] Pre-deposition inspection: after confirming that the boron nitride (BN) layer deposition and the first cross-linking interface layer are complete and have no defects, the deposition of the carbon layer is prepared to begin; the operating settings of the hot-wall chemical vapor deposition (CVD) system are maintained, and the optimal conditions for carbon layer deposition are adjusted;

[0086] Carbon source gas injection: inject methane (CH4, gas flow rate of 100 cm 2 / min) gas (with the addition of silane gas) into the CVD system to start the carbon layer deposition process; the process includes initial silicon-doped deposition (first silicon doping, ensuring that the amount of silicon doping in the initial stage is 0.1% of the volume percentage of the carbon layer, i.e., the initial growth and doping of the carbon layer), middle stage deposition, and late stage doping deposition (second silicon doping, ensuring that the amount of silicon doping in the late stage is 0.1% of the volume percentage of the carbon layer, i.e., silicon is continuously doped in the late stage until the end of the carbon layer, i.e., silicon doping is performed at the surface of the carbon layer away from the boron nitride layer); the deposition temperature throughout the deposition process is 1000°C, and the total deposition time is 3h, resulting in a mold brick structure with a deposited carbon layer (during the deposition process, a spectrometer is used to monitor the growth and quality of the coating in real time);

[0087] Post-processing and cooling: after the deposition is complete, gradually reduce the temperature of the hot-wall CVD system and allow the coating to cool naturally;

[0088] Quality inspection: after cooling, the carbon layer coating is visually and instrumentally inspected to ensure no defects; using precise measuring tools such as micrometer, confirm that the thickness of the carbon layer meets the specification requirements;

[0089] (4) Formation of the second cross-linking interface layer

[0090] The side surface of the carbon layer away from the body of the mold brick is subjected to a first cross-linking treatment of methyltrichlorosilane (0.5 mL / cm 2 ) at a temperature of 300°C for 3h, forming a first cross-linking interface layer on the surface of the carbon layer;

[0091] (5) Silicon carbide layer (SiC layer) deposition

[0092] Preparation for SiC layer deposition: Set up a precursor impregnation-pyrolysis (PIP) device, prepare and adjust the PIP device for SiC layer deposition;

[0093] SiC layer deposition: Select silicon carbide (SiC) precursor: Use polymethylsilane (MMS) as the precursor of the SiC layer; immerse the mold brick with deposited carbon layer in the SiC precursor solution, ensure uniform adsorption; after immersion, place the mold brick in a suitable environment to remove unreacted precursors; then perform pyrolysis at 1200°C for 4h to obtain a mold brick structure with a deposited SiC layer (during the deposition process, a spectrometer is used to monitor the growth and quality of the coating in real time), thereby obtaining the coating structure;

[0094] Post-processing and cooling: After deposition, gradually reduce the temperature of the device and allow the coating to cool naturally;

[0095] Quality inspection: After cooling, visually and instrumentally inspect the SiC layer to ensure no defects; use precise measuring tools such as micrometers to confirm that the thickness of the SiC layer meets the specification requirements.

[0096] Further, the present embodiment also provides a ceramic mold brick, as shown, comprising a ceramic mold brick body 1 (i.e., the mold brick in step (1)) and the above-mentioned surface coating. Figure 1

[0097] Embodiment 2

[0098] The present embodiment provides a surface coating of a ceramic mold brick, which comprises, in the direction from close to the ceramic mold brick body to far from the ceramic mold brick body, a boron nitride layer (thickness 0.2μm), a carbon layer (thickness 3μm), and a silicon carbide layer (thickness 3μm) stacked in sequence.

[0099] The boron nitride layer and the carbon layer further comprise a first interfacial crosslinking layer; the carbon layer and the silicon carbide layer further comprise a second interfacial crosslinking layer; the carbon layer at the surface layer close to the first interfacial crosslinking layer is subjected to first silicon doping (the doping amount of the first silicon doping in the carbon layer is 0.05% by volume); the carbon layer at the surface layer close to the second interfacial crosslinking layer is subjected to second silicon doping (the doping amount of the second silicon doping in the carbon layer is 0.5% by volume).

[0100] The preparation method of the surface coating is as follows:

[0101] (1) Boron nitride (BN) layer deposition

[0102] ​Pre-treatment and pre-heating of the mold brick: the pre-treated mold brick (mold brick type: high-temperature resistant silicon carbide-based ceramic) is placed in the reaction chamber of a hot-wall chemical vapor deposition (Thermal CVD) system; the hot-wall CVD system slowly heats the reaction chamber to the set deposition temperature, preventing thermal stress from occurring in the mold brick; precise temperature monitoring equipment such as thermocouples is used to ensure that the temperature of the mold brick is uniform throughout the pre-heating process;

[0103] Gas injection and boron nitride layer deposition: inject borohydride (borane: gas flow rate of 50 cm 2 / min) and ammonia gas (gas flow rate of 100 cm 2 / min) into the hot-wall CVD system to start the BN layer deposition process; the deposition temperature is 900°C, and the deposition time is 1.5 h, resulting in a boron nitride layer on the surface of the mold brick body (during the deposition process, a spectrometer is used to monitor the growth and quality of the coating in real time);

[0104] Post-processing and cooling: after the deposition is complete, gradually reduce the temperature of the hot-wall CVD system to allow the coating to cool naturally;

[0105] Quality inspection: after cooling, visually and instrumentally inspect the BN coating to ensure that it is defect-free; use precise measurement tools such as micrometers to confirm that the thickness of the BN layer meets the specification requirements;

[0106] (2) Formation of the first cross-linked interface layer

[0107] Perform first cross-linking treatment on the side surface of the boron nitride layer that is away from the mold brick body using methyltrichlorosilane (amount used: 0.1 mL / cm 2 ), at a temperature of 150°C for 4 h, forming a first cross-linked interface layer on the surface of the boron nitride layer;

[0108] (3) Carbon layer deposition

[0109] Deposition of the carbon layer on the surface of the first cross-linked interface layer:

[0110] Pre-deposition inspection: after confirming that the boron nitride (BN) layer deposition and the first cross-linked interface layer are complete and defect-free, prepare to start the carbon layer deposition; maintain the operating settings of the hot-wall chemical vapor deposition (CVD) system and adjust them to the optimal conditions for carbon layer deposition;

[0111] Carbon source gas injection: inject methane (CH4, gas flow rate of 200 cm 2 / min) gas (simultaneously incorporating silane gas), starting the deposition process of the carbon layer; including initial silicon-doped deposition (first silicon doping, ensuring the amount of silicon doping is 0.05% of the volume percentage of the carbon layer in the initial stage, i.e. the initial growth and doping of the carbon layer), middle stage deposition and late stage doping deposition (second silicon doping, ensuring the amount of silicon doping is 0.05% of the volume percentage of the carbon layer in the late stage, i.e. silicon is always doped in the late stage until the end of the carbon layer, i.e. silicon doping is performed at the surface of the carbon layer away from the boron nitride layer), the deposition temperature of the entire deposition process is 800°C, the total deposition time is 2.5h, and a mold brick structure with a deposited carbon layer is obtained (during the deposition process, a spectrometer is used to monitor the growth and quality of the coating in real time);

[0112] Post-processing and cooling: after the deposition is completed, the temperature of the hot-wall CVD system is gradually reduced, and the coating is allowed to cool naturally;

[0113] Quality inspection: after cooling, the carbon layer coating is visually and instrumentally inspected to ensure that it is defect-free; precise measuring tools such as micrometers are used to confirm that the thickness of the carbon layer meets the specification requirements;

[0114] (4) Formation of the second cross-linking interface layer

[0115] The surface of the carbon layer away from the body of the mold brick is subjected to a first cross-linking treatment with methyltrichlorosilane (0.1mL / cm 2 ) at a temperature of 200°C for 4h, forming a first cross-linking interface layer on the carbon surface;

[0116] (5) Deposition of the silicon-carbon compound layer (SiC layer)

[0117] Preparation for deposition of the SiC layer: set up a precursor impregnation-pyrolysis (PIP) device, prepare and adjust the PIP device for deposition of the SiC layer;

[0118] Deposition of the SiC layer: select a silicon carbide (SiC) precursor: use polymethylsilane (MMS) as the precursor for the SiC layer; immerse the mold brick with the deposited carbon layer in the SiC precursor solution to ensure uniform adsorption; after immersion, place the mold brick in a suitable environment to remove unreacted precursors; then perform pyrolysis at 1000°C for 3.5h, obtaining a mold brick structure with a deposited SiC layer (during the deposition process, a spectrometer is used to monitor the growth and quality of the coating in real time), thereby obtaining the coating structure;

[0119] Post-processing and cooling: after the deposition is completed, the temperature of the device is gradually reduced, and the coating is allowed to cool naturally;

[0120] Quality inspection: after cooling, the SiC layer is visually and instrumentally inspected to ensure that it is defect-free; precise measuring tools such as micrometers are used to confirm that the thickness of the SiC layer meets the specification requirements.

[0121] Further, the embodiment also provides a ceramic mold brick, comprising a mold brick body (i.e. the mold brick in step (1)) and the surface coating described above.

[0122] Embodiment 3

[0123] The embodiment provides a surface coating of a ceramic mold brick, which comprises, in the direction from the ceramic mold brick body to the ceramic mold brick body, a boron nitride layer (1 μm in thickness), a carbon layer (2 μm in thickness) and a silicon-carbon compound layer (5 μm in thickness) stacked in sequence.

[0124] The surface coating further comprises a first cross-linking interface layer between the boron nitride layer and the carbon layer, and a second cross-linking interface layer between the carbon layer and the silicon-carbon compound layer; the carbon layer is subjected to a first silicon doping (the doping amount of the first silicon doping in the carbon layer is 0.01% in volume percentage) at the surface layer close to the first cross-linking interface layer, and the carbon layer is subjected to a second silicon doping (the doping amount of the second silicon doping in the carbon layer is 1% in volume percentage) at the surface layer close to the second cross-linking interface.

[0125] The preparation method of the surface coating is as follows:

[0126] (1) Boron nitride (BN) layer deposition

[0127] Pre-treatment and pre-heating of the mold brick: the pre-treated mold brick (the mold brick is borosilicate glass) is placed in the reaction chamber of a hot-wall chemical vapor deposition (Thermal CVD) system; the hot-wall CVD system slowly heats the reaction chamber to a set deposition temperature to prevent thermal stress of the mold brick; precise temperature monitoring equipment such as thermocouples is used to ensure that the temperature of the mold brick is uniform during the whole pre-heating process;

[0128] Gas injection and boron nitride layer deposition: borohydride (borane: gas flow rate is 10 cm 2 / min) and ammonia gas (gas flow rate is 20 cm 2 / min) are injected into the hot-wall CVD system to start the BN layer deposition process; the deposition temperature is 1100°C, and the deposition time is 1 h to obtain the boron nitride layer on the surface of the mold brick body (during the deposition process, a spectrometer is used to monitor the growth and quality of the coating in real time);

[0129] Post-treatment and cooling: after the deposition is completed, the temperature of the hot-wall CVD system is gradually reduced to allow the coating to cool naturally;

[0130] Quality inspection: after cooling, the BN coating is subjected to visual and instrumental inspection to ensure that there is no defect; precise measuring tools such as micrometers are used to confirm that the thickness of the BN layer meets the specification requirements;

[0131] (2) Formation of the first cross-linking interface layer

[0132] The side surface of the boron nitride layer away from the body of the mold brick was subjected to a first cross-linking treatment with methyltrichlorosilane (1 mL / cm 2 ) at a temperature of 250°C for 1 h, forming a first cross-linking interface layer on the surface of the boron nitride layer;

[0133] (3) Carbon layer deposition

[0134] Deposition of a carbon layer on the surface of the first cross-linking interface layer:

[0135] Pre-deposition inspection: After confirming that the boron nitride (BN) layer deposition and the first cross-linking interface layer are complete and defect-free, the deposition of the carbon layer is prepared to begin; the operating settings of the hot-wall chemical vapor deposition (CVD) system are maintained, and the optimal conditions for carbon layer deposition are adjusted;

[0136] Carbon source gas injection: Injecting methane (CH4, gas flow rate of 50 cm 2 / min) gas (with the addition of silane gas) into the CVD system to start the carbon layer deposition process; including initial silicon-doped deposition (first silicon doping, ensuring that the amount of silicon doping is 0.01% of the volume percentage of the carbon layer in the initial stage, i.e., the initial growth and doping of the carbon layer), middle-stage deposition, and late-stage doping deposition (second silicon doping, ensuring that the amount of silicon doping is 1% of the volume percentage of the carbon layer in the late stage, i.e., silicon doping throughout the late stage until the end of the carbon layer, i.e., silicon doping at the surface of the carbon layer away from the boron nitride layer), the deposition temperature throughout the deposition process is 800°C, and the total deposition time is 1 h, obtaining a mold brick structure with a deposited carbon layer (during the deposition process, a spectrometer is used to monitor the growth and quality of the coating in real time);

[0137] Post-processing and cooling: After the deposition is complete, gradually reduce the temperature of the hot-wall CVD system, and allow the coating to cool naturally;

[0138] Quality inspection: After cooling, visually and instrumentally inspect the carbon layer coating to ensure that it is defect-free; using precise measurement tools such as micrometers, confirm that the thickness of the carbon layer meets the specification requirements;

[0139] (4) Formation of a second cross-linking interface layer

[0140] The side surface of the carbon layer away from the body of the mold brick was subjected to a first cross-linking treatment with methyltrichlorosilane (1 mL / cm 2 ) at a temperature of 250°C for 1 h, forming a first cross-linking interface layer on the surface of the carbon layer;

[0141] (5) Silicon-carbon compound layer (SiC layer) deposition

[0142] Preparation for SiC layer deposition: Set up a precursor infiltration-pyrolysis (PIP) device, and prepare and adjust the PIP device for SiC layer deposition;

[0143] SiC layer deposition: Selecting silicon carbide (SiC) precursor: using polymethylsilane (MMS) as the precursor of SiC layer; the mold brick with deposited carbon layer is immersed in the SiC precursor solution to ensure uniform adsorption; after immersion, the mold brick is placed in a suitable environment to remove unreacted precursors; then pyrolysis treatment at 1100℃ is carried out, and the pyrolysis time is 2h, to obtain the mold brick structure with deposited SiC layer (during the deposition process, a spectrometer is used to monitor the growth and quality of the coating in real time), thereby obtaining the coating structure;

[0144] Post-processing and cooling: after the deposition is completed, the temperature of the device is gradually reduced, and the coating is allowed to cool naturally;

[0145] Quality inspection: after cooling, the SiC layer is visually and instrumentally inspected to ensure that there are no defects; precise measuring tools such as micrometers are used to confirm that the thickness of the SiC layer meets the specification requirements.

[0146] Further, the embodiment also provides a ceramic mold brick, which comprises a mold brick body (i.e. the mold brick in step (1)) and the above-mentioned surface coating.

[0147] Example 4

[0148] The difference between this embodiment and Example 1 is that the thickness of the boron nitride layer in this embodiment is 3μm.

[0149] In the preparation method, the deposition time in step (1) is controlled to be 2.5h.

[0150] The rest of the preparation method and parameters remain the same as in Example 1.

[0151] Example 5

[0152] The difference between this embodiment and Example 1 is that the thickness of the carbon layer in this embodiment is 0.5μm.

[0153] In the preparation method, the deposition time in step (3) is controlled to be 1h.

[0154] The rest of the preparation method and parameters remain the same as in Example 1.

[0155] Example 6

[0156] The difference between this embodiment and Example 1 is that the thickness of the carbon layer in this embodiment is 4μm.

[0157] In the preparation method, the deposition time in step (3) is controlled to be 3.5h.

[0158] The rest of the preparation method and parameters remain the same as in Example 1.

[0159] Example 7

[0160] The difference between this example and Example 1 is that the thickness of the silicon-carbon compound layer in this example is 2 μm; the preparation method, the cracking time in step (5) is adjusted to 2 h.

[0161] The rest of the preparation method and parameters are consistent with Example 1.

[0162] Example 8

[0163] The difference between this example and Example 1 is that the thickness of the silicon-carbon compound layer in this example is 6 μm; the preparation method, the cracking time in step (5) is adjusted to 4 h.

[0164] The rest of the preparation method and parameters are consistent with Example 1.

[0165] Example 9

[0166] The difference between this example and Example 1 is that this example does not contain the first cross-linking interface layer;

[0167] In the preparation method, step (2) is not performed.

[0168] The rest of the preparation method and parameters are consistent with Example 1.

[0169] Example 10

[0170] The difference between this example and Example 1 is that this example does not contain the second cross-linking interface layer.

[0171] In the preparation method, step (4) is not performed.

[0172] The rest of the preparation method and parameters are consistent with Example 1.

[0173] Example 11

[0174] The difference between this example and Example 1 is that this example does not perform the first silicon doping;

[0175] In the preparation method, the silicon doping of the initial deposition of the carbon layer in step (3) is not performed.

[0176] The rest of the preparation method and parameters are consistent with Example 1.

[0177] Example 12

[0178] The difference between this example and Example 1 is that this example does not perform the second silicon doping;

[0179] In the preparation method, the silicon doping of the late deposition of the carbon layer in step (3) is not performed.

[0180] The rest of the preparation method and parameters are consistent with Example 1.

[0181] Comparative Example 1

[0182] The difference between this comparative example and Example 1 is that the coating structure in this comparative example does not contain a boron nitride layer.

[0183] In the preparation method, the deposition of the boron nitride layer in step (1) and the preparation of the first cross-linked interface layer in step (2) are not performed; the pre-processed and pre-heated mold brick is directly subjected to deposition of the carbon layer.

[0184] The remaining preparation method and parameters are consistent with those of Example 1.

[0185] Comparative Example 2

[0186] The difference between this comparative example and Example 1 is that the coating structure in this comparative example does not contain a carbon layer.

[0187] In the preparation method, the deposition of the carbon layer in step (3) and the preparation of the first cross-linked interface layer in step (4) are not performed.

[0188] The remaining preparation method and parameters are consistent with those of Example 1.

[0189] Comparative Example 3

[0190] The difference between this comparative example and Example 1 is that the coating structure in this comparative example does not contain a silicon-carbon compound layer.

[0191] In the preparation method, steps (4) and (5) are not performed.

[0192] The remaining preparation method and parameters are consistent with those of Example 1.

[0193] Comparative Example 4

[0194] The difference between this comparative example and Example 1 is that the stacking order of the boron nitride layer and the silicon-carbon compound layer in this comparative example is exchanged.

[0195] In the preparation process, the preparation process is adjusted adaptively.

[0196] The remaining preparation method and parameters are consistent with those of Example 1.

[0197] Comparative Example 5

[0198] The difference between this comparative example and Example 1 is that the stacking order of the carbon layer and the silicon-carbon compound layer in this comparative example is exchanged.

[0199] In the preparation process, the preparation process is adjusted adaptively.

[0200] The remaining preparation method and parameters are consistent with those of Example 1.

[0201] The ceramic tiles with surface coating structure provided by Examples 1-12 and Comparative Examples 1-5 were subjected to performance tests:

[0202] Adhesion strength test: the adhesion between the coating and the substrate was measured by tensile test using a universal testing machine. Under the test conditions, the application speed was 1 mm / min until the coating separated from the substrate, and the maximum force required was recorded.

[0203] High temperature resistance test: the sample was heated to 1000°C in a high temperature furnace for 2 hours, and then quickly cooled to room temperature, the changes in the surface and structure of the material were checked, and the stability and integrity of the coating at high temperature were evaluated;

[0204] Oxidation resistance test: the sample was placed in an oxidizing atmosphere (air) heated to 800°C for 3 hours, and the oxidation resistance of the coating was evaluated by comparing the weight change before and after;

[0205] Mechanical property test: a microhardness tester was used to measure the hardness and elastic modulus of the coating. A load of 500g was used, the duration was 15 seconds, and at least 5 points were measured to ensure consistency of the results;

[0206] The test results of the above tests are shown in Table 1.

[0207] Table 1

[0208]

[0209]

[0210] From Table 1, it can be seen that:

[0211] From the data results of Example 1 and Examples 4-8, it can be seen that the thickness of the boron nitride layer, the thickness of the carbon layer and the thickness of the silicon-carbon compound layer are too thin or too thick, which will cause the mechanical strength and thermal stability of the coating to decrease, thereby affecting the functionality and durability of the entire coating system. The appropriate thickness is a key factor to ensure excellent performance.

[0212] From the data results of Example 1 and Examples 9 and 10, it can be seen that without setting a cross-linking interface layer, the adhesion strength and interface compatibility between the coatings cannot be improved, which will cause the coating to delaminate and peel under high temperature or mechanical load, affecting its practicality.

[0213] From the data results of Example 1 and Examples 11 and 12, it can be seen that without first silicon doping and / or second silicon doping of the carbon layer, the oxidation resistance and thermal conductivity of the carbon layer will be affected, and silicon doping helps to improve the structural stability and chemical corrosion resistance of the carbon layer, thereby ensuring the performance of the coating in extreme environments.

[0214] From the data results of the example 1 and the comparative examples 1-5, it can be seen that the surface coating structure of the ceramic mold brick provided by the application, the boron nitride layer, the carbon layer and the silicon-carbon compound layer and the laminating sequence can realize the optimal physical and chemical properties, including high heat resistance, superior mechanical properties and excellent oxidation resistance, through the synergistic cooperation. A certain film layer structure or the exchange of the laminating sequence cannot obtain the required comprehensive performance, the characteristics of each layer and the sequence have a decisive influence on the final performance, and the wrong structure or sequence will greatly weaken the function of the coating.

[0215] In summary, through the synergistic cooperation of the boron nitride layer, the carbon layer and the silicon-carbon compound layer, the application significantly improves the performance of the overall coating while maintaining the unique performance of each material, creates a composite coating system that can withstand high temperature environment and protect the base material, thereby improving the heat resistance, oxidation resistance and mechanical strength of the ceramic mold brick, ensuring high-quality production while reducing costs and improving economic benefits.

[0216] The applicant declares that the above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the application can be easily thought of by any person skilled in the art in the technical field, and all fall within the protection scope and disclosure scope of the application.

Claims

1. A surface coating for ceramic molding bricks, characterized in that, The surface coating comprises, in the direction from the ceramic die brick body to the ceramic die brick body, a boron nitride layer, a carbon layer and a silicon-carbon compound layer in sequence.

2. The surface coating of a ceramic dielectric brick according to claim 1, characterized in that, The thickness of the boron nitride layer is 0.2-2 μm.

3. The surface coating of a ceramic dielectric brick according to claim 1, characterized in that, The thickness of the carbon layer is 1-3 μm.

4. The surface coating for ceramic molding bricks according to claim 1, characterized in that, The thickness of the silicon-carbon compound layer is 3-5 μm.

5. The surface coating for ceramic molding bricks according to claim 1, characterized in that, The boron nitride layer and the carbon layer further comprise a first cross-linking interface layer.

6. The surface coating for ceramic molding bricks according to claim 5, characterized in that, The carbon layer and the silicon-carbon compound layer further comprise a second cross-linking interface layer.

7. The surface coating of a ceramic dielectric brick according to claim 6, characterized in that, The carbon layer is subjected to first silicon doping at the surface layer close to the first cross-linking interface layer, and / or the carbon layer is subjected to second silicon doping at the surface layer close to the second cross-linking interface layer.

8. The surface coating of a ceramic dielectric brick according to claim 7, characterized in that, The doping amount of the first silicon doping in the carbon layer is 0.01-0.1% in volume percentage.

9. The surface coating of a ceramic dielectric brick according to claim 7, characterized in that, The doping amount of the second silicon doping in the carbon layer is 0.1-1% in volume percentage.

10. A method of producing a surface coating of a ceramic mould brick as claimed in any one of claims 1 to 9, characterised in that, The preparation method comprises the following steps: The boron nitride layer, the carbon layer and the silicon-carbon compound layer are sequentially compounded on the surface of the ceramic die brick body.

11. The preparation method according to claim 10, characterized in that: The boron nitride is compounded by the following method: The boron source and the nitrogen source are deposited on the surface of the ceramic die brick body by chemical vapor deposition to obtain the boron nitride layer.

12. The method of claim 11, wherein, The boron source comprises boron hydride.

13. The preparation method according to claim 11, characterized in that The nitrogen source comprises ammonia.

14. The method of claim 11, wherein, The gas flow rate of the boron source is 10 to 50 cm 2 / min.

15. The preparation method according to claim 11, characterized in that The gas flow rate of the nitrogen source is 20-100 cm 2 / min.

16. The method of claim 11, wherein, During the deposition of the boron nitride, the temperature of the chemical vapor deposition is 900-1100 ℃, and the time of the chemical vapor deposition is 1-3 h.

17. The method of claim 11, wherein, After the deposition of the boron nitride layer, the surface of the boron nitride layer is subjected to first cross-linking treatment.

18. The method of claim 17, wherein, The cross-linking agent of the first cross-linking treatment comprises an organic silicon cross-linking agent.

19. The method of claim 17, wherein, The amount of crosslinking agent used in the first crosslinking process is 0.1-1 mL / cm 2 .

20. The method of claim 17, wherein, The cross-linking temperature of the first cross-linking treatment is 150-300 ℃.

21. The method of claim 17, wherein, The cross-linking time of the first cross-linking treatment is 1-4 h.

22. The method of claim 10, wherein, The carbon layer is compounded by the following method: The carbon source is deposited on the surface of the boron nitride layer by chemical vapor deposition to obtain the carbon layer.

23. The method of claim 22, wherein, The gas flow rate of the carbon source during deposition of the carbon layer is 50-200 cm 2 / min.

24. The method of claim 22, wherein, During the deposition of the carbon layer, the temperature of the chemical vapor deposition is 800-1000 ℃, and the time of the chemical vapor deposition is 1-2 h.

25. The preparation method according to claim 22, characterized in that During the deposition of the carbon layer, the deposition gas is further doped with silicon; the doping is performed in stages, the initial doping amount is 0.01-0.1% in volume percentage, and the later doping amount is 0.1-1% in volume percentage.

26. The method of claim 22, wherein, After the deposition of the carbon layer, the surface of the carbon layer is subjected to second cross-linking treatment.

27. The method of claim 26, wherein, The cross-linking agent of the second cross-linking treatment comprises an organic silicon cross-linking agent.

28. The preparation method according to claim 26, characterized in that The amount of crosslinking agent used in the second crosslinking process is 0.1-1 mL / cm 2 .

29. The preparation method according to claim 26, characterized in that The cross-linking temperature of the second cross-linking treatment is 200-300 ℃.

30. The method of claim 26, wherein, The cross-linking time of the second cross-linking treatment is 1-4 h.

31. The method of claim 10, wherein, The silicon-carbon compound layer is compounded by the following method: The deposition of the silicon-carbon compound layer is performed by a precursor impregnation-pyrolysis method.

32. The method of claim 31, wherein, The ceramic die brick after the deposition of the carbon layer is immersed in a silicon-carbon compound precursor to obtain the silicon-carbon compound layer by pyrolysis.

33. The preparation method according to claim 31, characterized in that The pyrolysis temperature is 1000-1200 ℃, and the pyrolysis time is 2-4 h.

34. The method of claim 10, wherein, The preparation method comprises the following steps: The boron source and the nitrogen source are deposited on the surface of the ceramic mold brick body by a chemical vapor deposition method to obtain a boron nitride layer, and an organic silicon crosslinking agent is used to perform first crosslinking treatment on the boron nitride layer at 150-300 ℃ for 1-4 h with a dosage of 0.1-1 mL / cm 2 ; The carbon source is deposited onto the surface of the cross-linked boron nitride layer by a chemical vapor deposition method to obtain a carbon layer, and silicon is doped in the deposition gas during the deposition of the carbon layer; the doping is performed in stages, the initial doping amount is 0.01 to 0.1 volume percent, and the later doping amount is 0.1 to 1 volume percent; after the carbon layer is deposited, the carbon layer is subjected to a second cross-linking treatment at 200 to 300 DEG C using an organosilicon cross-linking agent in an amount of 0.1 to 1 mL / cm 2 ​ After the cross-linking treatment of the carbon layer, the ceramic die brick after the deposition of the carbon layer is immersed in a silicon-carbon compound precursor to obtain the silicon-carbon compound layer by pyrolysis, thereby obtaining the surface coating of the ceramic die brick.

35. A ceramic molding brick, characterized by The ceramic die brick comprises a ceramic die brick body and a surface coating on the surface of the ceramic die brick body, wherein the surface coating is as claimed in any one of claims 1-34.

36. Use of a ceramic die block as claimed in claim 35 in a HUD glass curve mirror.

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