Silicide high-temperature ceramic coating for oxidation / ablation protection and preparation method of silicide high-temperature ceramic coating

Abstract

The invention discloses a silicide high-temperature ceramic coating for oxidation / ablation protection and a preparation method of the silicide high-temperature ceramic coating, and belongs to the technical field of preparation of high-temperature protective coatings. The method comprises the following steps: putting a carbon matrix material into a reaction chamber of a chemical vapor deposition furnace, then vacuumizing, putting transition metal element chloride into a solid precursor gasification furnace, and heating and gasifying the transition metal element chloride after the chemical vapor deposition furnace reaches a set temperature; the SiCl4 tank is heated, carrier gas H2 is introduced into the SiCl4 tank, the carrier gas H2 is introduced into the solid precursor gasification furnace, gasified SiCl4 and transition metal element chloride are brought into a gas mixing tank by the carrier gas H2 to be fully mixed, then the mixture is introduced into a reaction chamber of the chemical vapor deposition furnace, and argon is introduced; and depositing on the surface of the carbon matrix material, stopping introducing gas after deposition is completed, cooling under the protection of argon, and naturally cooling to room temperature along with the furnace to obtain the silicide high-temperature ceramic coating. According to the invention, a chemical vapor deposition technology is adopted, and the silicide ceramic protective coating is prepared under a specific deposition system of SiCl4-transition metal element chloride-H2-Ar.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature protective coating preparation, and in particular relates to a silicide high-temperature ceramic coating for oxidation / ablation protection and a preparation method thereof. Background Art

[0002] Carbon / carbon (C / C) composite materials have the characteristics of low density, high specific strength, and excellent high-temperature mechanical properties. They are ideal materials for high-temperature structural parts and are often used as thermal protection components such as aircraft throat liners and blades. They are important candidate materials in high-tech fields such as aerospace. However, C / C composite materials have insufficient antioxidant properties. They begin to oxidize at 370°C, and their oxidation rate gradually increases with increasing temperature. Therefore, how to solve the problem of high-temperature oxidation has become the key to the application of C / C composite materials.

[0003] For example, the prior art "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 by embedding infiltration process, which relies on the HfSiO4-SiO2 film formed by oxidation on the coating surface to play an oxygen barrier role. For another example, the Chinese patent with publication number CN116730747A provides a carbon-based composite material surface glass ceramic anti-oxidation coating and its preparation method, which performs high-temperature liquid phase sintering on a prefabricated layer containing a large amount of hafnium-based ceramics, so that the HfO2 produced by oxidation of HfSi2 and HfB2 in the prefabricated layer is fully infiltrated by the liquid phase SiO2 glass, and HfSiO4 is obtained by in-situ reaction, and finally an anti-oxidation coating inlaid with HfSiO4-SiO2 glass ceramics is obtained, thereby improving the high-temperature anti-oxidation performance of the silicon-based ceramic coating. Another prior art disclosed in "Preparation of TaSi2-modified ZrB2 / SiC composite powder and study on the oxidation resistance of coating" mentioned that with the increase of TaSi2, the eutectic area of ​​the coating will increase and the density of the coating will be significantly improved. Through ablation test, it was found that the addition of TaSi2 can increase the content of SiO2 and produce TaZr with good thermal stability. 2.75 O8 effectively improves the anti-oxidation and ablation performance of the coating.

[0004] Anti-oxidation ablation coating technology can provide oxidation resistance at higher temperatures by blocking the contact between oxygen and the substrate through the coating, which is an important way to protect C / C composite materials from oxidation. Chemical vapor deposition technology (CVD) has the advantages of designable coating composition and structure, controllable reaction atmosphere, and high coating bonding strength. It is one of the most effective methods for preparing anti-oxidation coatings. However, there are currently few reports on the preparation of silicide ceramic coatings by chemical vapor deposition, and it is impossible to provide technical support for the preparation of silicide ceramic coatings with dense structures and uniformly distributed components. Summary of the invention

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

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

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

[0008] S1: placing the carbon matrix material into the reaction chamber of the chemical vapor deposition furnace, then evacuating the reaction chamber of the chemical vapor deposition furnace, placing the transition metal element chloride in the solid precursor gasification furnace, and heating and gasifying the transition metal element chloride after the chemical vapor deposition furnace reaches the set temperature;

[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, and the vaporized SiCl4 and transition metal chloride are brought into the mixing tank by the carrier gas H2 to be fully mixed, and then introduced into the reaction chamber of the chemical vapor deposition furnace, and argon gas is introduced;

[0010] S3: Deposition is performed on the surface of the carbon matrix material. After the deposition is completed, H2, argon, transition metal chloride carrier gas and SiCl4 carrier gas are sequentially turned off. After cooling down under the protection of argon, the material is naturally cooled to room temperature with the furnace 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 element chloride is HfCl4;

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

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

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

[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 S2, the heating temperature of the SiCl4 tank is 25-60°C.

[0019] In one embodiment, in S2, the flow rate of H2 is 2-5 L / min; the flow rates of the carrier gas of 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°C / min; the target temperature of the cooling is 400°C.

[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 adopts SiCl4-transition metal chloride-H2-Ar as the coating deposition system;

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

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

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

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

[0027] The present invention provides a method for preparing a silicide high-temperature ceramic coating for oxidation / ablation protection, the core of which is to use chemical vapor deposition technology to prepare a silicide ceramic protective coating in a specific deposition system of SiCl4-transition metal chloride-H2-Ar. By precisely controlling the proportion of each component gas and the reaction conditions, a silicide ceramic protective coating is successfully deposited on the target substrate. This method not only simplifies the preparation process, but also realizes precise control of the coating composition and structure, significantly enhancing its anti-oxidation and anti-ablation properties. During the preparation process, a mixed gas such as SiCl4 (as a silicon source), transition metal chloride, and H2 (reducing gas) is fully mixed in advance in a gas mixing tank. This step ensures the high uniformity of the gas when it is transported to the deposition area, thereby ensuring the uniformity of the final coating composition and the consistency of thickness. This preparation method exhibits significant advantages of simple operation, good repeatability, and stable process.

[0028] Furthermore, the vaporized SiCl4 and transition metal chloride are fully mixed in the gas mixing tank under the guidance of H2 carrier gas. This mixing method helps to form a uniform mixed gas, providing a stable source of raw materials for the subsequent deposition process. The uniform mixing in the gas mixing tank can effectively avoid the stratification phenomenon that may occur during the flow of different raw materials, ensuring that the mixed gas has consistent composition and concentration when entering the reaction deposition chamber.

[0029] On the other hand, the present invention provides a silicide high temperature ceramic coating for oxidation / ablation protection prepared by the above preparation method, such as TaSi2 prepared by TaCl5 as Ta source; HfSi2 prepared by HfCl4 as Hf source; ZrSi2 prepared by ZrCl4 as Zr source. The above silicide coating has good high temperature oxidation resistance, broadens the traditional high temperature resistant oxidation resistance ceramic coating system, and improves the protection life of carbon matrix materials in high temperature service environment.

[0030] Furthermore, a TaSi2 coating was prepared on the surface of the carbon / carbon composite material. Under extreme oxyacetylene ablation conditions exceeding 1800°C, the coating can form molten Ta2O5 and dense glass phase SiO2, which can not only effectively resist high-temperature oxidation, but also automatically heal defects such as cracks and holes on the coating surface during the ablation process, thereby significantly improving the overall anti-oxidation and ablation performance of the coating. This feature fully demonstrates the composition advantages and application potential of silicide high-temperature ceramic coatings in extreme environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the XRD spectrum of the silicide high temperature ceramic coating of the present invention;

[0032] Figure 2 The middle figure (a) and figure (b) are SEM photos of the surface and cross section of the silicide high temperature ceramic coating at 1100°C, respectively;

[0033] Figure 3 The middle figure (a) and figure (b) are SEM photos of the surface and cross section of the silicide high temperature ceramic coating at 1200℃ respectively;

[0034] Figure 4 Schematic diagram of the mass and linear ablation rate of silicide high-temperature ceramic coating after oxyacetylene ablation. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

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

[0037] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0038] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0039] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

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

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

[0042] S1: placing the carbon matrix material into the reaction chamber of the chemical vapor deposition furnace, then evacuating the reaction chamber of the chemical vapor deposition furnace, placing the transition metal element chloride in the solid precursor gasification furnace, and heating and gasifying the transition metal element chloride after the chemical vapor deposition furnace reaches the set temperature;

[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, and the vaporized SiCl4 and transition metal chloride are brought into the mixing tank by the carrier gas H2 to be fully mixed, and then introduced into the reaction chamber of the chemical vapor deposition furnace, and argon gas is introduced;

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

[0045] In the above steps, a chemical vapor deposition process is used to prepare a silicide high temperature ceramic coating, and a suitable precursor is selected, such as transition metal chloride and SiCl4, which can decompose and react at high temperature to form the desired silicide ceramic coating. The precursor is pretreated, such as heated and vaporized, to ensure that it enters the reaction chamber evenly in a gaseous form. A carrier gas is used to bring the vaporized precursor into the reaction chamber and help form a uniform airflow in the reaction chamber. The flow rate and speed of the carrier gas are precisely controlled to ensure that the precursor gas can be evenly distributed in the reaction chamber and form a uniform coating on the surface of the substrate material.

[0046] In addition, in order to promote the gasification and preliminary 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 transform from liquid to gas through the flow of hydrogen, and to assist the efficient volatilization of transition metal chlorides in the gasifier. Under the guidance of the carrier gas, the gasified SiCl4 and transition metal chlorides enter the mixing tank. In the mixing tank, the two gases are fully mixed under turbulent or laminar flow conditions to ensure that they achieve a high degree of uniformity before entering the reaction deposition chamber. The uniformly mixed gas is then passed into the reaction deposition chamber, chemically reacting with the surface of the carbon matrix material pre-placed therein, and ultimately forming the desired silicide ceramic coating.

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

[0048] Step 1: placing the pretreated carbon matrix material in a reaction chamber of a chemical vapor deposition furnace;

[0049] Step 2: Pre-treatment, evacuate the reaction chamber of the chemical vapor deposition furnace to 20-100Pa, maintain the pressure to check the airtightness of the deposition furnace, and put an appropriate amount of transition metal chloride such as TaCl5 (50-150g) into a crucible in a vacuum glove box, place the crucible in a solid precursor gasification furnace, and heat the solid precursor gasification furnace after the deposition furnace reaches a set temperature of 1000-1200°C. The 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 the SiCl4 tank, introduce carrier gas H2 into the solid precursor gasification furnace, and the vaporized SiCl4 and transition metal chloride are brought into the mixing tank by the carrier gas H2 to be fully mixed, and then the carrier with transition metal chlorides such as TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. Open and introduce H2, transition metal chloride carrier gas and SiCl4 carrier gas, and set the flow rates to 2-5L / min, 0.5-2L / min, and 0.5-2L / min respectively.

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

[0052] Specifically, the silicide ceramic coating uses SiCl4 as a silicon source; the transition metal chloride precursor is not limited to TaCl5, and preferably, it is satisfied that the volatilization temperature can stably volatilize the precursor at 260-500°C, such as HfCl4 and ZrCl4. The above 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, the carrier gas H2 can be introduced into the SiCl4 tank first, and the carrier gas H2 can be introduced into the transition metal chloride such as TaCl5 gasifier, and the vaporized SiCl4 and TaCl5 are brought into the mixing tank by the carrier gas to be fully mixed and introduced into the reaction deposition chamber. The heating evaporation temperature of transition metal chloride such as TaCl5 is 260-500°C, and the carrier heating temperature of SiCl4 is 25-60°C to meet the vaporization temperature requirements.

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

[0055] The present invention also provides a silicide high-temperature ceramic coating for oxidation / ablation protection, which adopts the above-mentioned 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 with TaCl5 as the Ta source is TaSi2; the silicide high-temperature ceramic coating prepared with HfCl4 as the Hf source is HfSi2; the silicide high-temperature ceramic coating prepared with ZrCl4 as the Zr source is ZrSi2.

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

[0057] Taking TaCl5 as Ta source to prepare TaSi2 as an example, in an oxyacetylene ablation environment greater than 1800°C, the silicide high-temperature ceramic coating of TaSi2 forms molten Ta2O5 and dense glass phase SiO2.

[0058] The TaSi2 coating on the surface of the carbon / carbon composite material forms molten Ta2O5 and dense glass phase SiO2 in an oxyacetylene ablation environment greater than 1800°C, which can effectively self-heal defects such as cracks and holes formed in the coating during the ablation process, improve the coating's anti-oxidation and ablation properties, and give full play to the composition advantages of the silicide high-temperature ceramic coating.

[0059] In summary, the preparation method provided by the present invention is simple to operate, highly repeatable, and has a stable process. The prepared silicide coating has good high-temperature oxidation resistance, expands the traditional high-temperature resistant and antioxidant ceramic coating system, and improves the protection life of carbon-based materials in high-temperature service environments.

[0060] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0061] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0062] Example 1

[0063] The pretreated carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace; the pretreatment is performed, the reaction chamber of the chemical vapor deposition furnace is evacuated to 50Pa, and the pressure is maintained to check the airtightness of the deposition furnace. When the pressure rise rate is less than 2Pa / h, the test can be started; 120g of TaCl5 powder is placed in a crucible in a vacuum glove box, and the crucible is placed in a solid precursor gasification furnace. After the chemical vapor deposition furnace reaches a set temperature of 1000℃, the gasification furnace is heated to 260℃; after heating the SiCl4 tank at 25℃, a carrier gas H2 is introduced into the SiCl4 tank, and a carrier gas H2 is introduced into the solid precursor gasification furnace. The vaporized SiCl4 and transition metal elements are reacted with the gasifier. The chloride TaCl5 is brought into the mixing tank by the carrier gas H2 and fully mixed. Then the carrier with TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. The carrier gas of H2, TaCl5 and SiCl4 are opened and introduced, and the flow rates are set to 2L / min, 0.6L / min and 0.8L / min respectively. After 5 hours of deposition, the carrier gas of H2, Ar, TaCl5 and SiCl4 are turned off in turn. After the chemical vapor deposition furnace is cooled to 400℃ at a rate of 10℃ / min under the protection of Ar, the power and Ar are turned off, and the furnace is cooled to room temperature to end the deposition, and the silicide ceramic coating can be obtained.

[0064] Example 2

[0065] The pretreated carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace; the pretreatment is performed, the reaction chamber of the chemical vapor deposition furnace is evacuated to 50Pa, and the pressure is maintained to check the airtightness of the deposition furnace. When the pressure rise rate is less than 2Pa / h, the test can be started; 120g of TaCl5 powder is placed in a crucible in a vacuum glove box, and the crucible is placed in a solid precursor gasification furnace. After the chemical vapor deposition furnace reaches a set temperature of 1100°C, the gasification furnace is heated to 260°C; after heating the SiCl4 tank at 25°C, a carrier gas H2 is introduced into the SiCl4 tank, and a carrier gas H2 is introduced into the solid precursor gasification furnace. The vaporized SiCl4 and transition metal elements are reacted with the catalyst to form a reaction mixture. The chloride TaCl5 is brought into the mixing tank by the carrier gas H2 and fully mixed. Then the carrier with TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. The carrier gas of H2, TaCl5 and SiCl4 are opened and introduced, and the flow rates are set to 2L / min, 0.5L / min and 0.5L / min respectively. After 5 hours of deposition, the carrier gas of H2, Ar, TaCl5 and SiCl4 are turned off in turn. After the chemical vapor deposition furnace is cooled to 400℃ at a rate of 10℃ / min under the protection of Ar, the power and Ar are turned off, and the furnace is cooled to room temperature to end the deposition, and the silicide ceramic coating can be obtained.

[0066] At a deposition temperature of 1100 °C, the XRD patterns of the coatings were Figure 1 As shown in Figure 2, the coating consists of only a single TaSi2 phase without any other impurity phases. The surface and cross-sectional microstructures of the prepared TaSi2 coating are shown in Figure 2. Figure 2 As shown, the surface of the coating prepared at this temperature is relatively dense, and the thickness of the coating is about 25 μm after deposition for 5 h.

[0067] Example 3

[0068] The pretreated carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace; the pretreatment is performed, the reaction chamber of the chemical vapor deposition furnace is evacuated to 50Pa, and the pressure is maintained to check the airtightness of the deposition furnace. When the pressure rise rate is less than 2Pa / h, the test can be started; 150g of TaCl5 powder is placed in a crucible in a vacuum glove box, and the crucible is placed in a solid precursor gasification furnace. After the chemical vapor deposition furnace reaches a set temperature of 1200°C, the gasification furnace is heated to 260°C; after heating the SiCl4 tank at 25°C, a carrier gas H2 is introduced into the SiCl4 tank, and a carrier gas H2 is introduced into the solid precursor gasification furnace. The vaporized SiCl4 and transition metal elements The chloride TaCl5 is brought into the mixing tank by the carrier gas H2 and fully mixed. Then, the carrier with TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. The carrier gas of H2, TaCl5 and SiCl4 are opened and introduced, and the flow rates are set to 2.5L / min, 0.5L / min and 0.5L / min respectively. After 5 hours of deposition, the carrier gas of H2, ArTaCl5 and SiCl4 are turned off in turn. After 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 turned off, and the furnace is cooled to room temperature to end the deposition, and the silicide ceramic coating can be obtained.

[0069] As the deposition temperature increases, Figure 3 As shown in the figure, under the deposition environment of 1200℃, the surface morphology of the prepared coating gradually becomes denser, the deposition efficiency of the coating increases, and the thickness of the coating reaches 52μm. In addition, the TaSi2 coating is tested under oxyacetylene ablation. Figure 4 As shown, the mass and line ablation rate are reduced by 32% and 48% respectively compared with the single SiC coating.

[0070] Example 4

[0071] The pretreated carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace; the pretreatment is performed, the reaction chamber of the chemical vapor deposition furnace is evacuated to 20Pa, and the pressure is maintained to check the airtightness of the deposition furnace. When the pressure rise rate is less than 2Pa / h, the test can be started; 50g of TaCl5 powder is placed in a crucible in a vacuum glove box, and the crucible is placed in a solid precursor gasification furnace. After the chemical vapor deposition furnace reaches a set temperature of 1000℃, the gasification furnace is heated to 500℃; after heating the SiCl4 tank at 45℃, a carrier gas H2 is introduced into the SiCl4 tank, and a carrier gas H2 is introduced into the solid precursor gasification furnace. The vaporized SiCl4 and transition metal The metal chloride TaCl5 is brought into the mixing tank by the carrier gas H2 and fully mixed. Then the carrier with TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. The carrier gas of H2, TaCl5 and SiCl4 are opened and introduced, and the flow rates are set to 5L / min, 2L / min and 2L / min respectively. After 7 hours of deposition, the carrier gas of H2, Ar, TaCl5 and SiCl4 are turned off in turn. After the chemical vapor deposition furnace is cooled to 400℃ at 2℃ / min under the protection of Ar, the power and Ar are turned off, and the furnace is cooled to room temperature to end the deposition, and the silicide ceramic coating can be obtained.

[0072] Example 5

[0073] The pretreated carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace; the pretreatment is performed, the reaction chamber of the chemical vapor deposition furnace is evacuated to 100Pa, and the airtightness of the deposition furnace is checked while maintaining the pressure. When the pressure rise rate is less than 2Pa / h, the test can be started; 120g of HfCl4 powder is placed in a crucible in a vacuum glove box, the crucible is placed in a solid precursor gasification furnace, and the gasification furnace is heated to 500℃ after the chemical vapor deposition furnace reaches a set temperature of 1100℃; after heating the SiCl4 tank at 60℃, a carrier gas H2 is introduced into the SiCl4 tank, and a carrier gas H2 is introduced into the solid precursor gasification furnace, and the vaporized SiCl4 and transition metal The metal chloride HfCl4 is brought into the mixing tank by the carrier gas H2 and fully mixed. Then the carrier with HfCl4 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. The carrier gases of H2, HfCl4 and SiCl4 are opened and introduced, and the flow rates are set to 5L / min, 1L / min, and 1L / min respectively. After 10 hours of deposition, the carrier gases of H2, Ar, HfCl4 and SiCl4 are turned off in turn. After the chemical vapor deposition furnace is cooled to 400°C at a rate of 5°C / min under the protection of Ar, the power and Ar are turned off, and the furnace is cooled to room temperature to end the deposition, and the silicide ceramic coating can be obtained.

[0074] Example 6

[0075] The pretreated carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace; the pretreatment is performed, the reaction chamber of the chemical vapor deposition furnace is evacuated to 70Pa, and the pressure is maintained to check the airtightness of the deposition furnace. When the pressure rise rate is less than 2Pa / h, the test can be started; 150g of ZrCl4 powder is placed in a crucible in a vacuum glove box, and the crucible is placed in a solid precursor gasification furnace. After the chemical vapor deposition furnace reaches a set temperature of 1200°C, the gasification furnace is heated to 260°C; after heating the SiCl4 tank at 25°C, a carrier gas H2 is introduced into the SiCl4 tank, and a carrier gas H2 is introduced into the solid precursor gasification furnace. The vaporized SiCl4 and the transition metal elements The chloride ZrCl4 is brought into the mixing tank by the carrier gas H2 and fully mixed. Then, the carrier with TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. The carrier gases of H2, ZrCl4 and SiCl4 are opened and introduced, and the flow rates are set to 2.5L / min, 0.5L / min and 0.5L / min respectively. After 5 hours of deposition, the carrier gases of H2, Ar, ZrCl4 and SiCl4 are turned off in turn. After 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 turned off, and the furnace is cooled to room temperature to end the deposition, and the silicide ceramic coating can be obtained.

[0076] Comparative Example 1

[0077] The pretreated carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace; the pretreatment is performed, the reaction chamber of the chemical vapor deposition furnace is evacuated to 50Pa, and the pressure is maintained to check the air tightness of the deposition furnace. When the pressure rise rate is less than 2Pa / h, the test can be started; 150g of TaCl5 powder is placed in a crucible in a vacuum glove box, and the crucible is placed in a solid precursor gasification furnace, and the gasification furnace is heated after the chemical vapor deposition furnace reaches the set temperature of 900℃; the carrier with TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas A is introduced. r, open and introduce H2, TaCl5 and SiCl4 carrier gases, set the flow rates to 2.5L / min, 0.5L / min and 0.5L / min respectively, without passing through the mixed gas tank, and input each precursor gas into the chemical vapor deposition furnace separately; after 5h of deposition, turn off the H2, Ar, TaCl5 carrier gas and SiCl4 carrier gas respectively, and after the chemical vapor deposition furnace is cooled to 400℃ at a rate of 10℃ / min under Ar protection, turn off the power and Ar, and cool the furnace to room temperature to end the deposition, and the silicide ceramic coating can be obtained.

[0078] By observing the samples after deposition, the results showed that each precursor was directly introduced into the chemical vapor deposition furnace without passing through a gas mixing tank. No deposited coating was found on the surface of the carbon substrate after the deposition was completed, and a large amount of white products adhered to the deposition furnace, blocking the gas pipeline.

[0079] Comparative Example 2

[0080] The pretreated carbon matrix material is placed in the reaction chamber of the chemical vapor deposition furnace; the pretreatment is performed, the reaction chamber of the chemical vapor deposition furnace is evacuated to 50Pa, and the pressure is maintained to check the airtightness of the deposition furnace. When the pressure rise rate is less than 2Pa / h, the test can be started; 120g of TaCl5 powder is placed in a crucible in a vacuum glove box, and the crucible is placed in a solid precursor gasification furnace. After the chemical vapor deposition furnace reaches a set temperature of 900℃, the gasification furnace is heated to 260℃; after heating the SiCl4 tank at 25℃, a carrier gas H2 is introduced into the SiCl4 tank, and a carrier gas H2 is introduced into the solid precursor gasification furnace. The gasified SiCl4 and the transition The metal chloride is brought into the mixing tank by the carrier gas H2 and fully mixed. Then the carrier with TaCl5 and SiCl4 is connected to the chemical vapor deposition furnace, and the protective gas Ar is introduced. The carrier gases of H2, TaCl5 and SiCl4 are opened and introduced, and the flow rates are set to 2L / min, 0.6L / min and 0.8L / min respectively. After 5 hours of deposition, the carrier gases of H2, Ar, TaCl5 and SiCl4 are turned off in turn. After 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 turned off, and the furnace is cooled to room temperature to end the deposition, and the silicide ceramic coating can be obtained.

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

[0082] In summary, the present invention provides a method for preparing a high temperature resistant silicide ceramic protective coating, which has a simple preparation process and can control the composition and structure of the silicide ceramic coating to improve its anti-oxidation / ablation performance. In addition, the mixed gas is fully mixed in the gas mixing tank in advance, which can improve the uniformity of the mixed gas during the transportation of SiCl4, transition metal chloride, Ar, H2 and other gases in the deposition process, ensure the uniformity of the coating composition and thickness, and prepare a silicide coating with excellent high temperature anti-oxidation performance.

[0083] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a silicide high temperature ceramic coating for oxidation / ablation protection, characterized in that: The following steps are involved: S1: placing the carbon matrix material into the reaction chamber of the chemical vapor deposition furnace, then evacuating the reaction chamber of the chemical vapor deposition furnace, placing the transition metal element chloride in the solid precursor gasification furnace, and heating and gasifying the transition metal element chloride after the chemical vapor deposition furnace reaches the set temperature; S2: Heat the SiCl4 tank and introduce carrier gas H2 into the SiCl4 tank, introduce carrier gas H2 into the solid precursor gasification furnace, and the vaporized SiCl4 and transition metal chloride are brought into the mixing tank by the carrier gas H2 to be fully mixed, and then introduced into the reaction chamber of the chemical vapor deposition furnace, and argon gas is introduced; S3: Deposition is performed on the surface of the carbon matrix material. After the deposition is completed, H2, argon, transition metal chloride carrier gas and SiCl4 carrier gas are sequentially turned off. After cooling down under the protection of argon, the material is naturally cooled to room temperature with the furnace to obtain a silicide high temperature ceramic coating.

2. The method for preparing a silicide high temperature ceramic coating for oxidation / ablation protection according to claim 1, characterized in that: The transition metal chloride is one of TaCl5, HfCl4 and ZrCl4; When the silicide high temperature ceramic coating is TaSi2, the transition metal chloride is TaCl5; When the silicide high temperature ceramic coating is HfSi2, the transition metal element chloride is HfCl4; When the silicide high temperature ceramic coating is ZrSi2, the transition metal element chloride is ZrCl4.

3. The method for preparing a silicide high temperature ceramic coating for oxidation / ablation protection according to claim 1, characterized in that: In S1, the pressure in the reaction chamber of the chemical vapor deposition furnace after the vacuum treatment is 20-100 Pa; the set temperature is 1000-1200°C; and the heating and gasification temperature of the transition metal chloride is 260-500°C.

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

5. The method for preparing a 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.

6. The method for preparing a silicide high temperature ceramic coating for oxidation / ablation protection according to claim 1, characterized in that: In S2, the heating temperature of the SiCl4 tank is 25-60°C.

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

8. The method for preparing a 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°C; The cooling rate is 2-10°C / min; the target temperature of the cooling is 400°C.

9. A silicide high temperature ceramic coating for oxidation / ablation protection prepared according to the preparation method according to any one of claims 1 to 8, 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 Si source; 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 with TaCl5 as the Ta source is TaSi2; the silicide high-temperature ceramic coating prepared with HfCl4 as the Hf source is HfSi2; and the silicide high-temperature ceramic coating prepared with ZrCl4 as the Zr source is ZrSi2.

10. The silicide high temperature ceramic coating for oxidation / ablation protection according to claim 9, characterized in that: In an oxyacetylene ablation environment of greater than 1800° C., the TaSi2 silicide high temperature ceramic coating forms molten Ta2O5 and dense glass phase SiO2.

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