A silicide high-temperature ceramic coating for oxidation / ablation protection and a method of making the same

Abstract

This invention discloses a silicide high-temperature ceramic coating for oxidation / ablation protection and its preparation method, belonging to the field of high-temperature protective coating preparation technology. The method is as follows: A carbon substrate material is placed in the reaction chamber of a chemical vapor deposition (CVD) furnace, followed by vacuum treatment. A transition metal chloride is placed in a solid precursor gasification furnace. After the CVD furnace reaches the set temperature, the transition metal chloride is heated and vaporized. A SiCl4 container is heated, and carrier gas H2 is introduced into the SiCl4 container. Carrier gas H2 is also introduced into the solid precursor gasification furnace. The vaporized SiCl4 and transition metal chloride are carried by the carrier gas H2 into a mixing tank for thorough mixing. This mixture is then introduced into the reaction chamber of the CVD furnace, and argon gas is introduced. Deposition is performed on the surface of the carbon substrate material. After deposition, the gas supply is turned off, and the material is allowed to cool naturally to room temperature under argon protection, thus obtaining a silicide high-temperature ceramic coating. This invention employs chemical vapor deposition technology to prepare a silicide ceramic protective coating in a specific deposition system of SiCl4-transition metal chloride-H2-Ar.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature protective coating preparation technology, specifically relating to a silicide high-temperature ceramic coating for oxidation / ablation protection and its preparation method. Background Technology

[0002] Carbon / carbon (C / C) composites possess characteristics such as low density, high specific strength, and excellent high-temperature mechanical properties, making them ideal materials for high-temperature structural components. They are commonly used in thermal protection components such as aircraft throat liners and blades, and are important candidate materials in high-tech fields such as aerospace. However, C / C composites have insufficient oxidation resistance, beginning to oxidize at 370℃, and the oxidation rate gradually increases with rising temperature. Therefore, solving the problem of easy oxidation at high temperatures is crucial for the application of C / C composites.

[0003] For example, the existing technology disclosed in "Li Shuping, Li Kezhi, Yuan Qinlu. Carbon-based composite material SiC-HfSi2 anti-ablation composite coating (English), Journal of the Chinese Ceramic Society 02(2010):352-356" discloses a technical solution for preparing HfSi2-SiC coating using an embedding and melting process, which relies on the HfSiO4-SiO2 film formed by oxidation on the coating surface to play an oxygen barrier role. Another example is Chinese patent CN116730747A, which provides a glass-ceramic anti-oxidation coating for carbon-based composite materials and its preparation method. This involves high-temperature liquid-phase sintering of a prefabricated layer containing a large amount of hafnium-based ceramics, allowing HfO2 produced by the oxidation of HfSi2 and HfB2 in the prefabricated layer to be fully wetted by the liquid-phase SiO2 glass, obtaining HfSiO4 through in-situ reaction, and finally obtaining an anti-oxidation coating with HfSiO4-SiO2 glass-ceramic inlay, thereby improving the high-temperature anti-oxidation performance of the silicon-based ceramic coating. Another prior art, "Preparation of TaSi2-modified ZrB2 / SiC composite powder and study on the antioxidant properties of the coating," mentions that with the increase of TaSi2, the eutectic region of the coating increases, and the coating density is significantly improved. Ablation tests show that the addition of TaSi2 can increase the SiO2 content and produce TaZr with good thermal stability. 2.75 O8 effectively improves the coating's resistance to oxidation and ablation.

[0004] Antioxidant ablation coating technology, by blocking oxygen from contacting the substrate through the coating, provides higher-temperature antioxidation capabilities and is an important approach to the oxidation protection of C / C composites. Chemical vapor deposition (CVD) technology has advantages such as designable coating composition and structure, controllable reaction atmosphere, and high coating adhesion strength, making it one of the most effective methods for preparing antioxidant coatings. However, there are currently few reports on the preparation of silicide ceramic coatings by CVD, which cannot provide technical support for the preparation of silicide ceramic coatings with dense structures and uniform compositional distribution. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a silicide high-temperature ceramic coating for oxidation / ablation protection and its preparation method, so as to improve the protection life of traditional silicide ceramic coatings against carbon / carbon composite materials and broaden the preparation system of chemical vapor deposition coatings.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] This invention provides a method for preparing a silicide high-temperature ceramic coating for oxidation / ablation protection, comprising the following steps:

[0008] S1: The carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace, and then the reaction chamber of the chemical vapor deposition furnace is evacuated. The transition metal chloride is placed in the solid precursor gasification furnace. After the chemical vapor deposition furnace reaches the set temperature, the transition metal chloride is heated and vaporized.

[0009] S2: Heat the SiCl4 tank and introduce carrier gas H2 into the SiCl4 tank. Introduce carrier gas H2 into the solid precursor gasification furnace. The gasified SiCl4 and transition metal chloride are carried by carrier gas H2 into the mixing tank for thorough mixing. Then, introduce it into the reaction chamber of the chemical vapor deposition furnace and introduce argon gas.

[0010] S3: Deposition is performed on the surface of a carbon matrix material. After deposition, H2, argon, transition metal chloride carrier gas and SiCl4 carrier gas are turned off in sequence. After cooling under argon protection, the furnace is naturally cooled to room temperature to obtain a silicide high-temperature ceramic coating.

[0011] In one embodiment, the transition metal chloride is one of TaCl5, HfCl4, and ZrCl4;

[0012] When the silicide high-temperature ceramic coating is TaSi2, the transition metal chloride is TaCl5.

[0013] When the silicide high-temperature ceramic coating is HfSi2, the transition metal chloride is HfCl4.

[0014] When the silicide high-temperature ceramic coating is ZrSi2, the transition metal chloride is ZrCl4.

[0015] In one embodiment, in S1, the pressure in the reaction chamber of the chemical vapor deposition furnace after vacuum treatment is 20-100 Pa; the set temperature is 1000-1200℃; and the heating and vaporization temperature of the transition metal element chloride is 260-500℃.

[0016] In one embodiment, in step S1, the amount of the transition metal chloride is 50-150g.

[0017] In one embodiment, in S2, the molar ratio of H2 to SiCl4 is 5:1; and the molar ratio of H2 to transition metal chloride is 10:1.

[0018] In one embodiment, in step S2, the heating temperature of the SiCl4 tank is 25-60°C.

[0019] In one embodiment, in step S2, the flow rate of H2 is 2-5 L / min; the flow rates of the carrier gas of the transition metal chloride and the carrier gas of SiCl4 are both 0.5-2 L / min.

[0020] In one embodiment, the deposition time is 2-10 hours; the deposition temperature is 1000-1200°C.

[0021] The cooling rate is 2-10℃ / min; the target temperature for cooling is 400℃.

[0022] The present invention also provides a silicide high-temperature ceramic coating for oxidation / ablation protection prepared by the above preparation method, wherein the silicide high-temperature ceramic coating uses SiCl4-transition metal chloride-H2-Ar as the coating deposition system.

[0023] SiCl4 was used as the Si source; the transition metal chloride was one of TaCl5, HfCl4 and ZrCl4, which were used as the Ta source, Hf source and Zr source, respectively.

[0024] The silicide high-temperature ceramic coating prepared by TaCl5 as Ta source is TaSi2; the silicide high-temperature ceramic coating prepared by HfCl4 as Hf source is HfSi2; and the silicide high-temperature ceramic coating prepared by ZrCl4 as Zr source is ZrSi2.

[0025] In one embodiment, under an oxyacetylene ablation environment at a temperature greater than 1800°C, the silicide high-temperature ceramic coating of TaSi2 forms molten Ta2O5 and dense glassy SiO2.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention provides a method for preparing a silicide high-temperature ceramic coating for oxidation / ablation protection. The core of this method lies in using chemical vapor deposition (CVD) technology to prepare a silicide ceramic protective coating in a specific deposition system of SiCl4-transition metal chloride-H2-Ar. By precisely controlling the proportions of each component gas and the reaction conditions, the silicide ceramic protective coating is successfully deposited on the target substrate. This method not only simplifies the preparation process but also achieves precise control over the coating composition and structure, significantly enhancing its oxidation and ablation resistance. During the preparation process, SiCl4 (as the silicon source), transition metal chloride, and H2 (reducing gas) are pre-mixed thoroughly in a mixing tank. This step ensures high uniformity of the gas when delivered to the deposition area, thereby guaranteeing the uniformity of the final coating composition and the consistency of its thickness. This preparation method exhibits significant advantages such as simple operation, good repeatability, and stable process.

[0028] Furthermore, the vaporized SiCl4 and transition metal chlorides are thoroughly mixed in the mixing tank under the guidance of H2 carrier gas. This mixing method helps to form a homogeneous gas mixture, providing a stable source of raw materials for the subsequent deposition process. Uniform mixing in the mixing tank effectively avoids stratification that may occur when different raw material gases flow, ensuring that the mixed gas has a consistent composition and concentration when it enters the reaction deposition chamber.

[0029] In another aspect, this invention provides silicide high-temperature ceramic coatings for oxidation / ablation protection prepared using the above-described methods. For example, a silicide high-temperature ceramic coating prepared using TaCl5 as the Ta source is called TaSi2; a silicide high-temperature ceramic coating prepared using HfCl4 as the Hf source is called HfSi2; and a silicide high-temperature ceramic coating prepared using ZrCl4 as the Zr source is called ZrSi2. These silicide coatings exhibit good high-temperature oxidation resistance, broadening the traditional high-temperature oxidation-resistant ceramic coating system and improving the protection lifespan of carbon-based materials under high-temperature service environments.

[0030] Furthermore, a TaSi2 coating was prepared on the surface of a carbon / carbon composite material. Under extreme oxyacetylene ablation conditions exceeding 1800℃, the coating formed molten Ta2O5 and dense glassy SiO2. This not only effectively resisted high-temperature oxidation but also automatically healed defects such as cracks and pores on the coating surface during ablation, thus significantly improving the overall oxidation and ablation resistance of the coating. This characteristic fully demonstrates the compositional advantages and application potential of silicide high-temperature ceramic coatings in extreme environments. Attached Figure Description

[0031] Figure 1 The XRD pattern of the silicide high-temperature ceramic coating of the present invention;

[0032] Figure 2 Figures (a) and (b) are SEM images of the surface and cross-section of the silicide high-temperature ceramic coating at 1100℃, respectively.

[0033] Figure 3 Figure (a) and Figure (b) are SEM images of the surface and cross-section of the silicide high-temperature ceramic coating at 1200℃, respectively.

[0034] Figure 4 This is a schematic diagram showing the quality and linear ablation rate of the silicide high-temperature ceramic coating after oxyacetylene ablation. Detailed Implementation

[0035] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0036] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0037] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0038] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0039] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0040] This invention provides a silicide high-temperature ceramic coating for oxidation / ablation protection and its preparation method.

[0041] The steps of the above preparation method are as follows:

[0042] S1: The carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace, and then the reaction chamber of the chemical vapor deposition furnace is evacuated. The transition metal chloride is placed in the solid precursor gasification furnace. After the chemical vapor deposition furnace reaches the set temperature, the transition metal chloride is heated and vaporized.

[0043] S2: Heat the SiCl4 tank and introduce carrier gas H2 into the SiCl4 tank. Introduce carrier gas H2 into the solid precursor gasification furnace. The gasified SiCl4 and transition metal chloride are carried by carrier gas H2 into the mixing tank for thorough mixing. Then, introduce it into the reaction chamber of the chemical vapor deposition furnace and introduce argon gas.

[0044] S3: Deposition is performed on the surface of a carbon matrix material. After deposition, H2, argon, transition metal chloride carrier gas and SiCl4 carrier gas are turned off in sequence. After cooling under argon protection, the furnace is naturally cooled to room temperature to obtain a silicide high-temperature ceramic coating.

[0045] In the above steps, a silicide high-temperature ceramic coating is prepared using chemical vapor deposition (CVD). Suitable precursors, such as transition metal chlorides and SiCl4, are selected to decompose and react at high temperatures to generate the desired silicide ceramic coating. The precursors are pretreated, such as by heating and vaporizing, to ensure they enter the reaction chamber uniformly in gaseous form. A carrier gas is used to carry the vaporized precursor into the reaction chamber and helps to form a uniform gas flow within it. The flow rate and velocity of the carrier gas are precisely controlled to ensure that the precursor gas is uniformly distributed within the reaction chamber and forms a uniform coating on the substrate material surface.

[0046] In addition, to facilitate the gasification and initial mixing of key raw materials, hydrogen (H2) is pre-introduced into a container containing silicon tetrachloride (SiCl4) and a gasifier containing transition metal chlorides such as TaCl5, HfCl4, and ZrCl4. The purpose of this step is to help SiCl4 transition from a liquid to a gaseous state through the flow of hydrogen and to facilitate the efficient volatilization of the transition metal chlorides in the gasifier. Guided by a carrier gas, the gasified SiCl4 and transition metal chlorides enter a mixing tank. Inside the mixing tank, the two gases are thoroughly mixed under turbulent or laminar flow conditions to ensure a high degree of homogeneity before entering the reactive deposition chamber. The homogeneously mixed gas is then introduced into the reactive deposition chamber, where it chemically reacts with the surface of a pre-placed carbon matrix material to ultimately form the desired silicide ceramic coating.

[0047] In one specific implementation, a method for preparing a silicide high-temperature ceramic coating for oxidation / ablation protection is provided, comprising the following steps:

[0048] Step 1: Place the pretreated carbon matrix material into the reaction chamber of the chemical vapor deposition furnace;

[0049] Step 2: Pretreatment: Evacuate the chemical vapor deposition furnace reaction chamber to 20-100 Pa and check the airtightness of the deposition furnace while maintaining pressure. Place an appropriate amount of transition metal chloride, such as TaCl5 (50-150g), into a crucible inside a vacuum glove box. Place the crucible in a solid precursor gasification furnace. After the deposition furnace reaches the set temperature of 1000-1200℃, heat the solid precursor gasification furnace. This heating temperature is the heating and gasification temperature of the transition metal chloride.

[0050] Step 3: Heat the SiCl4 tank and introduce carrier gas H2 into it. Introduce carrier gas H2 into the solid precursor gasification furnace. The gasified SiCl4 and transition metal chlorides are carried by the carrier gas H2 into the mixing tank for thorough mixing. Then, connect the carrier containing transition metal chlorides such as TaCl5 and SiCl4 to the chemical vapor deposition furnace, introduce protective gas Ar, and turn on and introduce H2, carrier gas of transition metal chlorides and carrier gas of SiCl4. Set the flow rate to 2-5 L / min, 0.5-2 L / min and 0.5-2 L / min respectively.

[0051] Step 4: After deposition for 2-10 hours, turn off H2, Ar, the carrier gas of transition metal chloride and SiCl4 in sequence. After the chemical vapor deposition furnace is cooled to 400℃ at 2-10℃ / min under Ar protection, turn off the power and Ar, and let the furnace cool to room temperature to end the deposition. The silicide ceramic coating can then be obtained.

[0052] Specifically, the silicide ceramic coating uses SiCl4 as the silicon source; the transition metal chloride precursor is not limited to TaCl5, but preferably, it is a precursor that can stably volatilize at a volatilization temperature of 260-500℃, such as HfCl4 and ZrCl4. The aforementioned transition metal chloride can be selected from one of TaCl5, HfCl4, and ZrCl4; the molar ratio of the carrier gas H2 / SiCl4 = 5:1; the molar ratio of the carrier gas H2 / transition metal chloride = 10:1; when the silicide high-temperature ceramic coating is TaSi2, the corresponding transition metal chloride is TaCl5; when the silicide high-temperature ceramic coating is HfSi2, the corresponding transition metal chloride is HfCl4; when the silicide high-temperature ceramic coating is ZrSi2, the corresponding transition metal chloride is ZrCl4.

[0053] Specifically, in step 3, carrier gas H2 can be first introduced into the SiCl4 tank and into the transition metal chloride gasifier such as TaCl5. The gasified SiCl4 and TaCl5 are then carried by the carrier gas into a mixing tank for thorough mixing before being introduced into the reaction deposition chamber. The heating and evaporation temperature of the transition metal chloride such as TaCl5 is 260-500℃, and the carrier heating temperature of SiCl4 is 25-60℃ to meet the gasification temperature requirements.

[0054] Specifically, the deposition temperature of the silicide ceramic coating is 1000-1200℃, and the deposition time is 2-10 hours.

[0055] The present invention also provides a silicide high-temperature ceramic coating for oxidation / ablation protection, using the above-mentioned SiCl4-transition metal chloride-H2-Ar as the coating deposition system; using SiCl4 as the Si source; the transition metal chloride is one of TaCl5, HfCl4 and ZrCl4, which are used as Ta source, Hf source and Zr source respectively; the silicide high-temperature ceramic coating prepared by TaCl5 as Ta source is TaSi2; the silicide high-temperature ceramic coating prepared by HfCl4 as Hf source is HfSi2; and the silicide high-temperature ceramic coating prepared by ZrCl4 as Zr source is ZrSi2.

[0056] Taking the preparation of TaSi2 using TaCl5 as the Ta source as an example, a chemical vapor deposition process is used in the SiCl4-TaCl5-H2-Ar deposition system, where SiCl4 is used as the Si source and the transition metal chloride TaCl5 is used as the Ta source, to prepare a silicide ceramic protective coating.

[0057] Taking the preparation of TaSi2 using TaCl5 as the Ta source as an example, under an oxyacetylene ablation environment at a temperature greater than 1800℃, the silicide high-temperature ceramic coating of TaSi2 forms molten Ta2O5 and dense glassy SiO2.

[0058] When the TaSi2 coating on the surface of carbon / carbon composite material is subjected to an oxyacetylene ablation environment above 1800℃, molten Ta2O5 and dense glassy SiO2 are formed. This effectively heals defects such as cracks and pores formed in the coating during the ablation process, improves the coating's resistance to oxidation and ablation, and fully leverages the compositional advantages of the silicide high-temperature ceramic coating.

[0059] In summary, the preparation method provided by this invention is simple to operate, highly repeatable, and has a stable process. It produces silicide coatings with good high-temperature oxidation resistance, broadens the traditional high-temperature oxidation-resistant ceramic coating system, and improves the protection life of carbon-based materials under high-temperature service environments.

[0060] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0061] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0062] Example 1

[0063] Pretreated carbon matrix material is placed in the reaction chamber of a chemical vapor deposition (CVD) furnace. For pretreatment, the CVD reaction chamber is evacuated to 50 Pa, and the pressure is maintained to check the furnace's airtightness. When the pressure rise rate is less than 2 Pa / h, the experiment can begin. 120 g of TaCl5 powder is placed in a crucible inside a vacuum glove box. The crucible is then placed in a solid precursor vaporization furnace. After the CVD furnace reaches the set temperature of 1000℃, the vaporization furnace is heated to 260℃. A SiCl4 container is heated at 25℃, and carrier gas H2 is introduced into the SiCl4 container and then into the solid precursor vaporization furnace. The vaporized SiCl4 and transition metal elements... The silicide TaCl5 is carried by the carrier gas H2 into the mixing tank and thoroughly mixed. Then, the carrier containing TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. H2, the carrier gas for TaCl5, and the carrier gas for SiCl4 are then introduced, with the flow rates set to 2 L / min, 0.6 L / min, and 0.8 L / min respectively. After 5 hours of deposition, the H2, Ar, TaCl5, and SiCl4 carrier gases are turned off sequentially. The chemical vapor deposition furnace is cooled to 400°C at a rate of 10°C / min under Ar protection. The power and Ar are then turned off, and the furnace is cooled to room temperature in the furnace cooling zone to complete the deposition, thus obtaining the silicide ceramic coating.

[0064] Example 2

[0065] Pretreated carbon matrix material is placed in the reaction chamber of a chemical vapor deposition (CVD) furnace. For pretreatment, the CVD reaction chamber is evacuated to 50 Pa, and the pressure is maintained to check the furnace's airtightness. If the pressure rise rate is less than 2 Pa / h, the experiment can begin. 120 g of TaCl5 powder is placed in a crucible inside a vacuum glove box. The crucible is then placed in a solid precursor vaporization furnace. After the CVD furnace reaches the set temperature of 1100 °C, the vaporization furnace is heated to 260 °C. A SiCl4 container is heated at 25 °C, and carrier gas H2 is introduced into the SiCl4 container and then into the solid precursor vaporization furnace. The vaporized SiCl4 and transition metal elements... The silicide TaCl5 is carried by the carrier gas H2 into the mixing tank and thoroughly mixed. Then, the carrier containing TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. H2, the carrier gas for TaCl5, and the carrier gas for SiCl4 are then introduced, with the flow rates set to 2 L / min, 0.5 L / min, and 0.5 L / min respectively. After 5 hours of deposition, the H2, Ar, TaCl5, and SiCl4 carrier gases are turned off sequentially. The chemical vapor deposition furnace is cooled to 400°C at a rate of 10°C / min under Ar protection. The power and Ar are then turned off, and the furnace is cooled to room temperature in the furnace cooling zone to complete the deposition, thus obtaining the silicide ceramic coating.

[0066] The XRD pattern of the coating prepared at a deposition temperature of 1100℃ is as follows: Figure 1 As shown, the coating consists of only a single TaSi2 phase, with no other impurity phases forming. The surface and cross-sectional microstructure of the prepared TaSi2 coating are as follows. Figure 2 As shown, the coating surface prepared at this temperature is relatively dense, and the coating thickness is approximately 25 μm after 5 hours of deposition.

[0067] Example 3

[0068] Pretreated carbon matrix material is placed in the reaction chamber of a chemical vapor deposition (CVD) furnace. For pretreatment, the CVD reaction chamber is evacuated to 50 Pa, and the pressure is maintained to check the furnace's airtightness. If the pressure rise rate is less than 2 Pa / h, the experiment can begin. 150 g of TaCl5 powder is placed in a crucible inside a vacuum glove box. The crucible is then placed in a solid precursor vaporization furnace. After the CVD furnace reaches the set temperature of 1200 °C, the vaporization furnace is heated to 260 °C. A SiCl4 container is heated at 25 °C, and carrier gas H2 is introduced into the SiCl4 container and then into the solid precursor vaporization furnace. The vaporized SiCl4 and transition metal elements... Chloride TaCl5 is carried by carrier gas H2 into a mixing tank and thoroughly mixed. Then, the carrier containing TaCl5 and SiCl4 is connected to a chemical vapor deposition furnace, and protective gas Ar is introduced. H2, carrier gas for TaCl5, and carrier gas for SiCl4 are then introduced, with flow rates set sequentially to 2.5 L / min, 0.5 L / min, and 0.5 L / min. After 5 hours of deposition, H2, Ar, carrier gas for TaCl5, and carrier gas for SiCl4 are sequentially turned off. The chemical vapor deposition furnace is cooled to 400°C at a rate of 10°C / min under Ar protection. The power supply and Ar are then turned off, and the furnace is cooled to room temperature in the furnace cooling zone to complete the deposition, thus obtaining a silicide ceramic coating.

[0069] As the deposition temperature increases, such as Figure 3 As shown, under a deposition environment of 1200℃, the surface morphology of the prepared coating gradually becomes denser, the deposition efficiency increases, and the coating thickness reaches 52 μm. Furthermore, the TaSi2 coating exhibits good performance under oxyacetylene ablation testing. Figure 4 As shown, its quality and line ablation rate were reduced by 32% and 48%, respectively, compared to a single SiC coating.

[0070] Example 4

[0071] Pretreated carbon matrix material was placed in the reaction chamber of a chemical vapor deposition (CVD) furnace. For pretreatment, the CVD reaction chamber was evacuated to 20 Pa, and the pressure was maintained to check the furnace's airtightness. When the pressure rise rate was less than 2 Pa / h, the experiment could begin. 50 g of TaCl5 powder was placed in a crucible inside a vacuum glove box. The crucible was then placed in a solid precursor vaporization furnace. After the CVD furnace reached the set temperature of 1000℃, the vaporization furnace was heated to 500℃. A SiCl4 container was heated to 45℃, and carrier gas H2 was introduced into the SiCl4 container and then into the solid precursor vaporization furnace. The vaporized SiCl4 and transition gold... The elemental chloride TaCl5 is carried by the carrier gas H2 into the mixing tank and thoroughly mixed. Then, the carrier containing TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. H2, the carrier gas of TaCl5, and the carrier gas of SiCl4 are turned on and introduced, and the flow rates are set to 5L / min, 2L / min, and 2L / min respectively. After deposition for 7 hours, the H2, Ar, the carrier gas of TaCl5, and the carrier gas of SiCl4 are turned off in sequence. The chemical vapor deposition furnace is cooled to 400°C at 2°C / min under Ar protection. Then, the power supply and Ar are turned off, and the furnace is cooled to room temperature with the furnace cooling zone to end the deposition. The silicide ceramic coating can then be obtained.

[0072] Example 5

[0073] Pretreated carbon matrix material was placed in the reaction chamber of a chemical vapor deposition (CVD) furnace. For pretreatment, the CVD reaction chamber was evacuated to 100 Pa, and the pressure was maintained to check the furnace's airtightness. When the pressure rise rate was less than 2 Pa / h, the experiment could begin. 120 g of HfCl4 powder was placed in a crucible inside a vacuum glove box. The crucible was then placed in a solid precursor vaporization furnace. After the CVD furnace reached the set temperature of 1100 °C, the vaporization furnace was heated to 500 °C. The SiCl4 container was heated to 60 °C, and then carrier gas H2 was introduced into the SiCl4 container and the solid precursor vaporization furnace. The vaporized SiCl4 and transition gold... The elemental chloride HfCl4 is carried by the carrier gas H2 into the mixing tank and thoroughly mixed. Then, the carrier containing HfCl4 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. The carrier gas of H2, HfCl4 and SiCl4 are turned on and introduced, and the flow rates are set to 5 L / min, 1 L / min and 1 L / min respectively. After deposition for 10 h, the carrier gas of H2, Ar, HfCl4 and SiCl4 are turned off in sequence. The chemical vapor deposition furnace is cooled to 400 °C at 5 °C / min under Ar protection. The power and Ar are turned off and the furnace is cooled to room temperature in the furnace cooling zone to end the deposition. The silicide ceramic coating can then be obtained.

[0074] Example 6

[0075] Pretreated carbon matrix material is placed in the reaction chamber of a chemical vapor deposition (CVD) furnace. For pretreatment, the CVD reaction chamber is evacuated to 70 Pa, and the pressure is maintained to check the furnace's airtightness. If the pressure rise rate is less than 2 Pa / h, the experiment can begin. 150 g of ZrCl4 powder is placed in a crucible inside a vacuum glove box. The crucible is then placed in a solid precursor vaporization furnace. After the CVD furnace reaches the set temperature of 1200 °C, the vaporization furnace is heated to 260 °C. The SiCl4 container is heated to 25 °C, and then carrier gas H2 is introduced into the SiCl4 container and the solid precursor vaporization furnace. The vaporized SiCl4 and transition metal elements... ZrCl4 chloride is carried by carrier gas H2 into a mixing tank and thoroughly mixed. Then, the carrier containing TaCl5 and SiCl4 is connected to a chemical vapor deposition furnace, and protective gas Ar is introduced. H2, ZrCl4 carrier gas, and SiCl4 carrier gas are turned on and introduced, with flow rates set to 2.5 L / min, 0.5 L / min, and 0.5 L / min respectively. After 5 hours of deposition, H2, Ar, ZrCl4 carrier gas, and SiCl4 carrier gas are turned off sequentially. The chemical vapor deposition furnace is cooled to 400°C at 10°C / min under Ar protection. The power supply and Ar are then turned off, and the furnace is cooled to room temperature in the furnace cooling zone to end the deposition process, thus obtaining a silicide ceramic coating.

[0076] Comparative Example 1

[0077] The pretreated carbon matrix material was placed in the reaction chamber of a chemical vapor deposition (CVD) furnace. For pretreatment, the CVD reaction chamber was evacuated to 50 Pa, and the pressure was maintained to check the airtightness of the deposition furnace. When the pressure rise rate was less than 2 Pa / h, the experiment could begin. 150 g of TaCl5 powder was placed in a crucible inside a vacuum glove box. The crucible was then placed in a solid precursor vaporization furnace. The furnace was heated after reaching the set temperature of 900 °C. A carrier containing TaCl5 and SiCl4 was then connected to the CVD furnace, and protective gas A was introduced. r, turn on and introduce carrier gases H2, TaCl5 and SiCl4, and set the flow rates to 2.5L / min, 0.5L / min and 0.5L / min respectively. Do not pass through the mixing tank. Each precursor gas is separately introduced into the chemical vapor deposition furnace. After 5 hours of deposition, turn off the carrier gases H2, Ar, TaCl5 and SiCl4 in sequence. The chemical vapor deposition furnace is cooled to 400℃ at 10℃ / min under Ar protection. Then turn off the power and Ar. Let the furnace cool to room temperature. The deposition is then completed, and the silicide ceramic coating can be obtained.

[0078] Observations of the deposited samples revealed that when the precursor was directly introduced into the chemical vapor deposition furnace without passing through the mixing tank, no deposited coating was found on the carbon matrix surface after deposition, and a large amount of white product adhered to the inside of the deposition furnace, blocking the gas path.

[0079] Comparative Example 2

[0080] Pretreated carbon matrix material was placed in the reaction chamber of a chemical vapor deposition (CVD) furnace. For pretreatment, the CVD reaction chamber was evacuated to 50 Pa, and the pressure was maintained to check the furnace's airtightness. When the pressure rise rate was less than 2 Pa / h, the experiment could begin. 120 g of TaCl5 powder was placed in a crucible inside a vacuum glove box. The crucible was then placed in a solid precursor vaporization furnace. After the CVD furnace reached the set temperature of 900 °C, the vaporization furnace was heated to 260 °C. After heating the SiCl4 container at 25 °C, carrier gas H2 was introduced into the SiCl4 container and then into the solid precursor vaporization furnace. The vaporized SiCl4 and transition gas... Metal chlorides are carried by carrier gas H2 into a mixing tank and thoroughly mixed. Then, a carrier containing TaCl5 and SiCl4 is connected to a chemical vapor deposition furnace, and a protective gas Ar is introduced. H2, TaCl5, and SiCl4 carrier gases are then introduced, with flow rates set sequentially to 2 L / min, 0.6 L / min, and 0.8 L / min. After 5 hours of deposition, the H2, Ar, TaCl5, and SiCl4 carrier gases are sequentially turned off. The chemical vapor deposition furnace is cooled to 400°C at a rate of 10°C / min under Ar protection. The power supply and Ar are then turned off, and the furnace is cooled to room temperature in the furnace cooling zone to complete the deposition, thus obtaining a silicide ceramic coating.

[0081] At a deposition temperature of 900℃, no coating was deposited on the surface of the carbon material substrate, and the morphology of the carbon material surface remained consistent with that before deposition, without any significant changes.

[0082] In summary, this invention provides a method for preparing a high-temperature resistant silicide ceramic protective coating. The preparation process is simple, and the composition and structure of the silicide ceramic coating can be controlled to improve its oxidation / ablation resistance. Furthermore, pre-mixing the mixed gas in a mixing tank improves the uniformity of the mixed gas during the deposition process, ensuring uniformity of coating composition and thickness, and resulting in a silicide coating with excellent high-temperature oxidation resistance.

[0083] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A silicide high-temperature ceramic coating for oxidation / ablation protection, characterized in that, The silicide high-temperature ceramic coating uses SiCl4-transition metal chloride-H2-Ar as the coating deposition system; SiCl4 is used as the Si source; the transition metal chloride is one of TaCl5, HfCl4 and ZrCl4, which are used as the Ta source, Hf source and Zr source, respectively; the silicide high-temperature ceramic coating prepared by using TaCl5 as the Ta source is TaSi2; under an oxyacetylene ablation environment above 1800℃, the TaSi2 silicide high-temperature ceramic coating forms molten Ta2O5 and dense glassy SiO2; The silicide high-temperature ceramic coating prepared by using HfCl4 as the Hf source is HfSi2; the silicide high-temperature ceramic coating prepared by using ZrCl4 as the Zr source is ZrSi2. The method for preparing the silicide high-temperature ceramic coating for oxidation / ablation protection includes the following steps: S1: The carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace, and then the reaction chamber of the chemical vapor deposition furnace is evacuated. The transition metal chloride is placed in the solid precursor gasification furnace. After the chemical vapor deposition furnace reaches the set temperature, the transition metal chloride is heated and vaporized. S2: Heat the SiCl4 tank and introduce carrier gas H2 into the SiCl4 tank. Introduce carrier gas H2 into the solid precursor gasification furnace. The gasified SiCl4 and transition metal chloride are carried by carrier gas H2 into the mixing tank for thorough mixing. Then, introduce it into the reaction chamber of the chemical vapor deposition furnace and introduce argon gas. S3: Deposition is performed on the surface of a carbon matrix material. After deposition, H2, argon, transition metal chloride carrier gas and SiCl4 carrier gas are turned off in sequence. After cooling under argon protection, the furnace is naturally cooled to room temperature to obtain a silicide high-temperature ceramic coating.

2. The silicide high-temperature ceramic coating for oxidation / ablation protection according to claim 1, characterized in that, In step S1, the pressure in the reaction chamber of the chemical vapor deposition furnace after vacuum treatment is 20-100 Pa; the set temperature is 1000-1200℃; and the heating and vaporization temperature of the transition metal element chloride is 260-500℃.

3. The silicide high-temperature ceramic coating for oxidation / ablation protection according to claim 1, characterized in that, In step S1, the amount of the transition metal chloride is 50-150g.

4. The silicide high-temperature ceramic coating for oxidation / ablation protection according to claim 1, characterized in that, In S2, the molar ratio of H2 to SiCl4 is 5:1; the molar ratio of H2 to transition metal chloride is 10:

1.

5. The silicide high-temperature ceramic coating for oxidation / ablation protection according to claim 1, characterized in that, In step S2, the heating temperature of the SiCl4 tank is 25-60℃.

6. The silicide high-temperature ceramic coating for oxidation / ablation protection according to claim 1, characterized in that, In step S2, the flow rate of H2 is 2-5 L / min; the flow rates of the carrier gas of the transition metal chloride and the carrier gas of SiCl4 are both 0.5-2 L / min.

7. The silicide high-temperature ceramic coating for oxidation / ablation protection according to claim 1, characterized in that, The deposition time is 2-10 hours; the deposition temperature is 1000-1200℃. The cooling rate is 2-10℃ / min; the target temperature for cooling is 400℃.

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