Graphite silicon carbide coating part and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor materials, in particular to a graphite silicon carbide coating part and a preparation method thereof. The preparation method comprises the following steps: introducing etching gas to etch the surface of a graphite substrate to obtain a pretreated graphite substrate; carrying out chemical vapor deposition treatment on the pretreated graphite substrate to form a silicon carbide coating, and preparing a graphite silicon carbide coating part; the etching gas comprises hydrogen, water vapor and first diluent gas. According to the preparation method, the graphite substrate is etched by using the gas containing hydrogen and water vapor, the surface of the graphite substrate is pretreated, and then the silicon carbide coating is formed on the pretreated surface of the graphite substrate by adopting chemical vapor deposition, so that the bonding strength of the silicon carbide coating and the graphite substrate is improved; the risk that the silicon carbide coating in the graphite silicon carbide coating part falls off and cracks in the heating and cooling use process is reduced, and the service life of the graphite silicon carbide coating part is prolonged.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a graphite silicon carbide coated part and a method for preparing the same. Background Technology

[0002] Graphite-silicon carbide coated parts combine the advantages of graphite (high thermal conductivity and low coefficient of thermal expansion) with silicon carbide (high-temperature oxidation resistance and wear resistance), making them widely used in semiconductor manufacturing. They can be used in processes such as silicon single crystal growth, silicon epitaxy, and silicon carbide epitaxy, for example, as a base for semiconductor epitaxy equipment.

[0003] Graphite-silicon carbide coated parts typically consist of a graphite substrate and a silicon carbide coating on the surface of the graphite substrate. The silicon carbide coating is usually deposited on the graphite substrate surface using chemical vapor deposition (CVD). However, there is a drawback: low bonding strength between the graphite substrate and the silicon carbide coating. During use, the coating is prone to peeling and cracking, affecting the service life of the graphite-silicon carbide coated parts. Summary of the Invention

[0004] Based on this, in order to solve the technical problem of low bonding strength between graphite substrate and silicon carbide coating, this application provides a graphite silicon carbide coated part and its preparation method.

[0005] A first aspect of this application provides a method for preparing a graphite silicon carbide coated part, the method comprising the following steps:

[0006] Etching gas is introduced to etch the surface of the graphite substrate to obtain a pretreated graphite substrate;

[0007] The pretreated graphite substrate is subjected to chemical vapor deposition to form a silicon carbide coating, thereby preparing the graphite silicon carbide coated part;

[0008] The etching gas includes hydrogen, water vapor, and a first dilution gas.

[0009] In some embodiments, the etching gas comprises, by mole percentage, 20% to 60% hydrogen, 0.5% to 5% water vapor, and the balance being a first dilution gas.

[0010] In some embodiments, the molar ratio of hydrogen to water vapor is 25 to 40:1.

[0011] In some embodiments, the flow rate of the etching gas is 20 SLM to 40 SLM; and / or,

[0012] The etching temperature is 600℃~1200℃; and / or,

[0013] The total etching time is 2 to 5 hours.

[0014] In some embodiments, the etching includes a first-stage etching and a second-stage etching performed sequentially;

[0015] The etching temperature in the first stage is 600℃~800℃. The etching gas used in the first stage of etching includes 40%~60% hydrogen, 1%~5% water vapor and the remainder is a first dilution gas.

[0016] The etching temperature in the second stage is 1000℃~1200℃. The etching gas used in the second stage of etching, in molar percentage terms, includes 20%~40% hydrogen, 0.5%~3% water vapor, and the remainder is a first dilution gas.

[0017] In some implementations, the etching time for the first stage is 1 to 2 hours.

[0018] In some implementations, the etching time for the second stage is 1 hour to 3 hours.

[0019] In some embodiments, the parameters of the chemical vapor deposition process include: the gas source used includes a second dilution gas, a carrier gas, and an organosilicon source gas; and the temperature is 1200°C to 1600°C.

[0020] In some embodiments, the carrier gas includes hydrogen; and / or,

[0021] The organosilicon source gas includes at least one of trichloromethylsilane, trichlorosilane, and tetrachlorosilane; and / or,

[0022] The carrier gas includes hydrogen; and / or,

[0023] The first diluting gas and the second diluting gas each independently include at least one of argon and helium.

[0024] In some embodiments, the thickness of the silicon carbide coating is 50 μm to 150 μm.

[0025] A second aspect of this application provides a graphite silicon carbide coated part, which is prepared according to the above-described method for preparing graphite silicon carbide coated parts.

[0026] The method for preparing graphite silicon carbide coated parts described in this application has the following beneficial effects:

[0027] In the above-mentioned method for preparing graphite silicon carbide coated parts, the graphite substrate is etched using a gas including hydrogen and water vapor to pretreat the surface of the graphite substrate. Then, a silicon carbide coating is formed on the surface of the pretreated graphite substrate by chemical vapor deposition. This improves the bonding strength between the silicon carbide coating and the graphite substrate, reduces the risk of the silicon carbide coating in the graphite silicon carbide coated parts peeling off and cracking during use when heating and cooling, and improves the service life of the graphite silicon carbide coated parts. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating a method for preparing a graphite silicon carbide coated part in some embodiments. Detailed Implementation

[0030] To facilitate understanding of this application, a more comprehensive description of the application will be provided below in conjunction with specific embodiments. Preferred embodiments of the application are given in the specific embodiments. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0031] 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 terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0033] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features.

[0034] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0035] In this application, terms such as "further," "even more," "particularly," "for example," "like," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the coverage of different technical solutions presented earlier and later, but should not be construed as limiting the preceding technical solution or restricting the scope of protection herein. Unless otherwise specified herein, A (e.g., B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0036] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0037] When a numerical range is disclosed in this application, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed in this application should be understood to include any and all subranges to which they are included.

[0038] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0039] The terms "comprising" and "having," and any variations thereof, used in the embodiments of this application, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to such processes, methods, products, or devices.

[0040] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0041] In the flowchart of this application, although the steps are shown sequentially according to the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps. They can be executed in other orders. Moreover, at least some of the steps in the diagram may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. Their execution order is not necessarily sequential, but can be performed alternately or in turn with at least some of other steps or other sub-steps or stages.

[0042] The first aspect of this application provides a method for preparing a graphite silicon carbide coated part, in conjunction with reference to... Figure 1 The preparation method includes the following steps:

[0043] S1: Etching gas is introduced to etch the surface of the graphite substrate to obtain a pretreated graphite substrate;

[0044] S2: Chemical vapor deposition is performed on the pretreated graphite substrate to form a silicon carbide coating, thus preparing a graphite silicon carbide coated part;

[0045] The etching gas includes hydrogen, water vapor, and a first dilution gas.

[0046] In the above-mentioned method for preparing graphite silicon carbide coated parts, the graphite substrate is etched using a gas including hydrogen and water vapor to pretreat the surface of the graphite substrate. Then, a silicon carbide coating is formed on the pretreated graphite substrate surface by chemical vapor deposition. This improves the bonding strength between the silicon carbide coating and the graphite substrate, reduces the risk of the silicon carbide coating in the graphite silicon carbide coated parts peeling off and cracking during use when heating and cooling, and improves the service life of the graphite silicon carbide coated parts.

[0047] In some embodiments, the etching temperature is 600°C to 1200°C. Exemplarily, it can be 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, or any value within a range formed by any two of these point values ​​as endpoints.

[0048] In some embodiments, the etching gas, by molar percentage, comprises 20% to 60% hydrogen, 0.5% to 5% water vapor, and the balance being a first dilution gas. Exemplarily, the hydrogen content can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, or any value within a range formed by any two of these values ​​as endpoints; the water vapor content can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any value within a range formed by any two of these values ​​as endpoints. It is understood that using an etching gas containing the above components to etch a graphite substrate allows for controllable etching rate regulation, increases the deposition surface area, enhances nucleation sites during chemical vapor deposition, and increases coating adhesion.

[0049] In some embodiments, the molar ratio of hydrogen to water vapor in the etching gas is 25 to 40:1. Exemplarily, it can be 25:1, 30:1, 35:1, 40:1, or any value within a range formed by any two of these point values ​​as endpoints.

[0050] In some embodiments, the first diluting gas includes at least one of argon and helium.

[0051] In some embodiments, the flow rate of the etching gas is 20 SLM to 40 SLM. Exemplarily, it can be 20 SLM, 25 SLM, 30 SLM, 35 SLM, 40 SLM, or any value within a range formed by any two of these point values ​​as endpoints.

[0052] Understandably, SLM (Standard Liter per Minute) is the standard unit of gas flow rate, an abbreviation for standard liters per minute, used to express the volumetric flow rate of a gas under standard conditions, which are usually defined as a temperature of 0°C and a pressure of 1 atm (101325 Pascals).

[0053] In some implementations, the total etching time is 2 to 5 hours. For example, it can be 2 hours, 3 hours, 4 hours, or 5 hours.

[0054] In some embodiments, etching includes a first-stage etching and a second-stage etching performed sequentially. It is understood that when etching consists of a first-stage etching and a second-stage etching performed sequentially, the compositions of the etching gases used in the first-stage etching and the second-stage etching each independently satisfy the aforementioned ranges; the temperatures of the first-stage etching and the second-stage etching each independently satisfy the aforementioned ranges; the flow rates of the etching gas in the first-stage etching and the second-stage etching each independently satisfy the aforementioned ranges; and the total etching time is the sum of the time for the first-stage etching and the time for the second-stage etching.

[0055] In some implementations, etching may consist of only a first-stage etching or a second-stage etching.

[0056] In some embodiments, the temperature of the first stage etching is 600°C to 800°C, and the etching gas used in the first stage etching, by molar percentage, includes 40% to 60% hydrogen, 1% to 5% water vapor, and the balance being a first dilution gas.

[0057] In some embodiments, the temperature of the second-stage etching is 1000°C to 1200°C, and the etching gas used in the second-stage etching includes 20% to 40% hydrogen, 0.5% to 3% water vapor, and the balance being a first dilution gas, by molar percentage.

[0058] In some embodiments, the molar ratio of hydrogen to water vapor in the etching gas used in the first stage of etching may be the same as or different from the molar ratio of hydrogen to water vapor in the etching gas used in the second stage of etching.

[0059] Understandably, the first stage of etching is carried out at a lower temperature and with higher hydrogen and water vapor content. Combined with the second stage of etching at a higher temperature and with lower hydrogen and water vapor content, the differences in the chemical reaction mechanism and kinetics of hydrogen and water vapor with graphite at different temperatures can be utilized. Specifically, the chemical reaction rate is slow at lower temperatures, so the etching rate can be appropriately increased by increasing the etching gas concentration. At higher temperatures, the chemical reaction rate is faster, so the etching rate can be appropriately reduced by decreasing the concentration. Based on this, the two etching processes are seamlessly connected, ultimately achieving graphite surface modification and improving the bonding strength between graphite and the silicon carbide coating.

[0060] In some implementations, the flow rate of the etching gas during the first stage of etching is 20 SLM to 40 SLM.

[0061] In some implementations, the etching time for the first stage is 1 to 2 hours.

[0062] In some embodiments, the flow rate of the etching gas during the second stage etching is 20 SLM to 40 SLM.

[0063] In some implementations, the second-stage etching time is 1 to 3 hours.

[0064] In some embodiments, the parameters of the chemical vapor deposition process include: the gas source used includes a second dilution gas, a carrier gas, and an organosilicon source gas; and the temperature is 1200°C to 1600°C.

[0065] In some implementations, the carrier gas includes hydrogen.

[0066] In some embodiments, the organosilicon source gas includes at least one of trichloromethylsilane (MTS), trichlorosilane, and tetrachlorosilane.

[0067] In some embodiments, the second diluent gas includes at least one of argon and helium.

[0068] In some embodiments, the ratio of the flow rates of the second dilution gas, the carrier gas, and the organosilicon source gas is (5~20):(5~20):1. For example, the ratio of the flow rate of the second dilution gas to the flow rate of the organosilicon source gas can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, or any value within a range formed by any two of these point values ​​as end values; the ratio of the flow rate of the carrier gas to the flow rate of the organosilicon source gas can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, or any value within a range formed by any two of these point values ​​as end values.

[0069] In some embodiments, the process of forming a silicon carbide coating by chemical vapor deposition on a pretreated graphite substrate includes:

[0070] The pretreated graphite substrate is placed in a chemical vapor deposition chamber, vacuumed, heated to 1200℃~1600℃ and held for 0.5h~1.5h, and then a second dilution gas, a carrier gas and an organosilicon source gas are introduced to perform chemical vapor deposition, forming a silicon carbide coating on the surface of the pretreated graphite substrate.

[0071] In some embodiments, the thickness of the silicon carbide coating is 50 μm to 150 μm. Exemplarily, the thickness of the silicon carbide coating can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, or any value within a range formed by any two of these point values ​​as endpoints.

[0072] A second aspect of this application provides a graphite silicon carbide coated article, which is prepared according to the above-described method for preparing graphite silicon carbide coated articles.

[0073] Understandably, the above-mentioned graphite silicon carbide coated part has a multi-layer structure, which includes a graphite substrate and a silicon carbide coating disposed on the surface of the graphite substrate.

[0074] To make the objectives and advantages of this application clearer, the preparation method and effects of the graphite silicon carbide coated parts of this application are further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining this application and should not be used to limit this application. Unless otherwise specified, the following embodiments do not include components other than unavoidable impurities. Unless otherwise specified, the drugs and instruments used in the embodiments are conventional choices in the art. Experimental methods in the embodiments that do not specify specific conditions are implemented according to conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0075] Example 1

[0076] S1: At 600℃, an etching gas composed of hydrogen, water vapor and argon in a molar ratio of 40:1:59 is introduced to perform the first stage etching on the surface of the graphite substrate. The flow rate of the etching gas in the first stage etching is 30 SLM, and the etching time in the first stage etching is 1 hour.

[0077] The temperature was raised to 1000℃, and an etching gas composed of hydrogen, water vapor and argon in a molar ratio of 20:0.5:79.5 was introduced to perform a second stage of etching on the surface of the graphite substrate after the first stage of etching. The flow rate of the etching gas in the second stage of etching was 30 SLM, and the second stage of etching time was 2 hours, resulting in a pretreated graphite substrate.

[0078] S2: The pretreated graphite substrate is placed in a chemical vapor deposition chamber, vacuumed, and heated to 1400℃. Then, argon, hydrogen and MTS are introduced in a volume flow ratio of 10:10:1 to deposit a silicon carbide coating with a thickness of 100μm on the surface of the pretreated graphite substrate.

[0079] Example 2

[0080] S1: At 800℃, an etching gas composed of hydrogen, water vapor and argon in a molar ratio of 50:2:48 is introduced to perform the first stage etching on the surface of the graphite substrate. The flow rate of the etching gas in the first stage etching is 40 SLM and the etching time in the first stage etching is 1 hour.

[0081] The temperature was raised to 1200℃, and an etching gas composed of hydrogen, water vapor and argon in a molar ratio of 25:1:74 was introduced to perform a second stage of etching on the surface of the graphite substrate after the first stage of etching. The flow rate of the etching gas in the second stage of etching was 40 SLM, and the second stage of etching time was 2 hours, resulting in a pretreated graphite substrate.

[0082] S2: The pretreated graphite substrate is placed in a chemical vapor deposition chamber, vacuumed, and heated to 1400℃. Then, argon, hydrogen and MTS are introduced in a volume flow ratio of 10:10:1 to deposit a silicon carbide coating with a thickness of 100μm on the surface of the pretreated graphite substrate.

[0083] Example 3

[0084] The process is basically the same as in Example 1, except that in step S1, etching is performed for 3 hours only under the conditions of the first stage etching.

[0085] The specific process of step S1 is as follows: at 600°C, an etching gas composed of hydrogen, water vapor and argon in a molar ratio of 40:1:59 is introduced to etch the surface of the graphite substrate. The flow rate of the etching gas is 30 SLM and the etching time is 3 hours.

[0086] Example 4

[0087] The process is basically the same as in Example 1, except that in step S1, etching is performed for 3 hours only under the conditions of the second stage etching.

[0088] The specific process of step S1 is as follows: at 1000℃, an etching gas composed of hydrogen, water vapor and argon in a molar ratio of 20:0.5:79.5 is introduced to etch the surface of the graphite substrate. The flow rate of the etching gas is 30 SLM and the etching time is 3h.

[0089] Example 5

[0090] The process is basically the same as in Example 2, except that the composition of the etching gas in the first stage of etching is adjusted to a molar ratio of hydrogen, water vapor and argon of 40:2:58, and the composition of the etching gas in the second stage of etching is adjusted to a molar ratio of hydrogen, water vapor and argon of 20:1:79.

[0091] Comparative Example 1

[0092] The process is basically the same as in Example 1, except that step S1 is omitted, and a silicon carbide coating is formed directly on the surface of the graphite substrate by chemical vapor deposition.

[0093] Comparative Example 2

[0094] It is basically the same as Example 1, except that in step S1, water vapor is replaced with the same molar amount of hydrogen.

[0095] Specifically, the process of step S1 is as follows:

[0096] At 600℃, an etching gas composed of hydrogen and argon in a molar ratio of 41:59 was introduced to perform the first stage etching on the surface of the graphite substrate. The flow rate of the etching gas in the first stage etching was 30 SLM, and the etching time in the first stage etching was 1 hour.

[0097] The temperature was raised to 1000℃, and an etching gas composed of hydrogen and argon in a molar ratio of 20.5:79.5 was introduced to perform a second stage of etching on the surface of the graphite substrate after the first stage of etching. The flow rate of the etching gas in the second stage of etching was 30 SLM, and the second stage of etching time was 2 hours, resulting in a pretreated graphite substrate.

[0098] Performance testing:

[0099] Adhesion: The adhesion between the silicon carbide coating and the graphite substrate was tested according to the method specified in GB / T 5210-2006.

[0100] The performance test results of the graphite silicon carbide coated parts of each embodiment and comparative example are shown in Table 1.

[0101] Table 1

[0102]

[0103] As shown in Table 1, compared with the comparative example, the graphite substrate and silicon carbide coating of the graphite silicon carbide coated parts prepared in the examples have higher bonding strength, which can reduce the risk of silicon carbide coating peeling and cracking during use when heating and cooling, and improve the service life of graphite silicon carbide coated parts.

[0104] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing a graphite silicon carbide coated part, characterized in that, The preparation method includes the following steps: Etching gas is introduced to etch the surface of the graphite substrate to obtain a pretreated graphite substrate; The pretreated graphite substrate is subjected to chemical vapor deposition to form a silicon carbide coating, thereby preparing the graphite silicon carbide coated part; The etching gas includes hydrogen, water vapor, and a first dilution gas.

2. The preparation method according to claim 1, characterized in that, The etching gas comprises, by mole percentage, 20% to 60% hydrogen, 0.5% to 5% water vapor, and the balance being a first dilution gas.

3. The preparation method according to claim 2, characterized in that, The molar ratio of hydrogen to water vapor is 25~40:

1.

4. The preparation method according to claim 1, characterized in that, The etching temperature is 600℃~1200℃; and / or, The flow rate of the etching gas is 20 SLM to 40 SLM; and / or, The total etching time is 2 to 5 hours.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The etching includes a first-stage etching and a second-stage etching performed sequentially. The etching temperature in the first stage is 600℃~800℃. The etching gas used in the first stage of etching includes 40%~60% hydrogen, 1%~5% water vapor and the remainder is a first dilution gas. The etching temperature in the second stage is 1000℃~1200℃. The etching gas used in the second stage of etching, in molar percentage terms, includes 20%~40% hydrogen, 0.5%~3% water vapor, and the remainder is a first dilution gas.

6. The preparation method according to claim 5, characterized in that, The etching time for the first stage is 1 hour to 2 hours; and / or, The second stage of etching takes 1 to 3 hours.

7. The preparation method according to any one of claims 1 to 4, characterized in that, The parameters of the chemical vapor deposition process include: the gas source used includes a second dilution gas, a carrier gas, and an organosilicon source gas; the temperature is 1200℃~1600℃.

8. The preparation method according to claim 7, characterized in that, The carrier gas includes hydrogen; and / or, The organosilicon source gas includes at least one of trichloromethylsilane, trichlorosilane, and tetrachlorosilane; and / or, The carrier gas includes hydrogen; and / or, The first diluting gas and the second diluting gas each independently include at least one of argon and helium.

9. The preparation method according to any one of claims 1 to 4, characterized in that, The thickness of the silicon carbide coating is 50μm~150μm.

10. A graphite-silicon carbide coated part, characterized in that, The graphite silicon carbide coated part is prepared by the method according to any one of claims 1 to 9.

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