Alternate deposition coating process and tantalum carbide coating
By separating carbon and tantalum deposition steps, the process addresses surface roughness and uneven distribution in tantalum carbide coatings, achieving a dense and uniform coating with enhanced adhesion and reduced material waste.
Patent Information
- Application Number
- CN202411358969.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-01-03
AI Technical Summary
Existing tantalum carbide coating processes face issues with surface roughness and uneven distribution due to gas phase nucleation of carbon source precursors, leading to poor adhesion and high material waste.
The process separates carbon and tantalum deposition steps, forming a carbon coating first, followed by tantalum, to suppress gas phase nucleation and improve adhesion, with controlled conditions for each step.
This approach results in a dense, uniform tantalum carbide coating with reduced roughness and improved adhesion, lowering material costs and simplifying processing.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the field of tantalum carbide coatings, in particular to an alternating deposition coating process and tantalum carbide coatings. Background Art
[0002] Coating technology is a widely used surface treatment process, which enables the base material component to obtain or enhance its target performance by coating a single layer or multiple layers of metal, alloy, ceramic and other materials on the surface of the base material. The current mainstream coating preparation technologies mainly include: brushing method, embedding method, chemical vapor deposition (CVD), magnetron sputtering deposition method, ion beam assisted deposition method, pulsed laser deposition method, liquid phase pulse discharge deposition method, etc.
[0003] Among them, chemical vapor deposition is widely used in the field of coating technology because it has a high deposition rate and can quickly obtain a high-density coating. When the existing CVD method is used to prepare carbide coating processes (taking tantalum carbide as an example) on a large scale, the traditional technical means is to simultaneously introduce precursors such as propylene, hydrogen, and TaCl5 to form a tantalum carbide coating under certain temperature and pressure conditions. For example, the prior art discloses a method for preparing a tantalum carbide coating by CVD, sublimating a tantalum salt into a gaseous state, introducing argon as a carrier gas, carrying the gaseous tantalum salt into a mixing tank, and mixing it with hydrogen and propylene for deposition reaction to obtain a tantalum carbide coating with high mechanical properties, corrosion resistance, and thermal shock resistance. The prior art also discloses a method for preparing a tantalum-tantalum carbide composite coating and its products. By introducing tantalum pentachloride or tantalum pentafluoride gas, mixed olefins, and hydrogen mixed gas into the reaction chamber, a tantalum carbide coating is prepared to improve the surface finish and the aesthetics of the product. However, none of these prior arts solve the above technical problems.
[0004] In this context, how to improve the quality of the coating, reduce the roughness of the surface of the tantalum carbide coating, and improve its surface finish has become a technical problem that needs to be urgently solved in this field. Summary of the invention
[0005] A first aspect of the present invention provides an alternating deposition plating process, which comprises: providing a component to be plated, and performing carbon deposition and tantalum deposition on the surface of the component to be plated, respectively, to obtain a tantalum carbide coating.
[0006] Preferably, the steps of respectively depositing carbon and tantalum on the surface of the component to be plated include:
[0007] S1. Preheating the part to be plated;
[0008] S2. Carbon deposition is performed on the surface of the component to be plated to form a carbon coating layer;
[0009] S3. Performing tantalum deposition on the carbon-plated layer to form a tantalum-plated layer, so as to obtain a tantalum carbide plating layer on the surface of the component to be plated.
[0010] In the traditional coating process, tantalum source, carbon source and reducing gas are introduced together for deposition reaction. The carbon source precursor is prone to gas phase nucleation under the coating conditions. On the one hand, the carbon source core formed by gas phase nucleation adsorbs tantalum source vapor, forming a relatively high concentration area at the nucleation center; on the other hand, the barrier for continued nucleation at the nucleation center is greatly reduced, so the tantalum source is easy to deposit on the carbon source core, inducing a large amount of tantalum source precursor to gas phase nucleation, and finally resulting in problems of uneven distribution and particle agglomeration.
[0011] The present invention innovatively separates the carbon deposition and tantalum deposition processes in time, and obtains a tantalum carbide coating through a process design of substrate-carbon coating-tantalum coating, fundamentally solving the gas phase nucleation problem that is easy to occur during the decomposition of carbon source precursors (such as propylene). By first introducing a carbon source precursor below 1000°C to form a carbon coating on the surface of the component to be tested, under this condition, the carbon source will not undergo gas phase nucleation but will be directly converted into deposited carbon, and the deposited carbon is used as a buffer layer between the tantalum carbide coating and the substrate (such as graphite), reducing the problem of easy shedding of the coating caused by the sudden change in the thermal expansion coefficient between the substrate materials when the tantalum carbide coating is directly deposited, and improving the adhesion between the coating and the substrate; by depositing tantalum on the carbon coating, the tantalum source precursor is converted from a compound to a single substance under the action of a reducing gas and fully reacts with the carbon coating. In this process, gaseous carbon and tantalum diffuse into each other's aggregation area at high temperature, and finally react to form a dense and uniform tantalum carbide coating. The tendency of gas phase nucleation particles to appear inside the obtained coating is significantly suppressed, and the quality of the coating is improved. At the same time, the waste of tantalum source precursor caused by induced gas phase nucleation of tantalum source precursor is solved, the utilization efficiency of tantalum source precursor is significantly improved, and the material cost is greatly reduced.
[0012] Preferably, the steps S2 and S3 are repeatedly cycled until the thickness of the tantalum carbide coating reaches a target thickness, and the number of cycles is an even number.
[0013] More preferably, the target thickness is 10 μm-20 μm.
[0014] In addition to improving the quality of tantalum carbide coating, the process proposed by the present invention can also realize cyclic operation to increase the coating sequence; that is, the coating sequence during actual processing can be designed as substrate-carbon coating-tantalum coating-...-tantalum coating, and the coating thickness can be flexibly adjusted according to demand, and carbon deposition and tantalum deposition are cyclically repeated according to the demand for target thickness. The carbon deposition and tantalum deposition conditions in each cycle can be independently adjusted according to the process requirements, and the controllability is strong. The process implementation conditions of the present invention are wide, and the process steps are simple and easy to implement, easy to promote in large-scale production, and the process is highly practical.
[0015] During the cyclic plating, it is preferred that the plating process finally terminates at the tantalum plating layer, which effectively avoids the defects of the deposited carbon easily adsorbing impurities and the low density of the plating; the plating is controlled to terminate at the tantalum plating layer, giving the plating layer excellent surface flatness and density, significantly improving the quality of the product.
[0016] Preferably, the step S2 comprises: setting the reaction environment temperature to 600° C.-1000° C., introducing a carbon source precursor and a protective gas to perform carbon deposition.
[0017] More preferably, the reaction environment temperature in step S2 is 800°C-1000°C.
[0018] Most preferably, the reaction environment temperature in step S2 is 850°C.
[0019] Preferably, in the step S2, the target reaction environment temperature is set while controlling the reaction environment pressure to 5000Pa-8000Pa; preferably, the reaction environment pressure is 6000Pa-7500Pa, and most preferably, the reaction environment pressure is 7000Pa.
[0020] Preferably, in step S2, the introduction time of the carbon source precursor is 1 min-60 min, and the flow rate of the carbon source precursor is 10 sccm-800 sccm.
[0021] More preferably, in step S2, the introduction time of the carbon source precursor is 5 min-50 min, and the flow rate of the carbon source precursor is 20 sccm-500 sccm.
[0022] Most preferably, in step S2, the introduction time of the carbon source precursor is 20 min, and the flow rate of the carbon source precursor is 50 sccm.
[0023] Preferably, the carbon source precursor has the general structural formula of C x H y , where 1≤x≤5, 2≤y≤8.
[0024] Examples of carbon source precursors include ethylene (C2H4), propylene (C3H6), methane (CH4), acetylene (C2H2), etc.; propylene is more preferred.
[0025] Preferably, the flow rate of the protective gas in step S2 is 0.5slm-60slm; more preferably, the flow rate of the protective gas is 1slm-30slm; and most preferably, the flow rate of the protective gas is 5slm.
[0026] The protective gas is an inert gas commonly used in the art, such as argon, nitrogen, etc., preferably argon.
[0027] Preferably, the step S3 includes: setting the reaction environment temperature to 1050° C.-2400° C., and introducing a tantalum source precursor and a carrier gas to perform tantalum deposition.
[0028] More preferably, the reaction environment temperature in step S3 is 1250°C-2000°C.
[0029] Most preferably, the reaction environment temperature in step S3 is 1600°C.
[0030] Preferably, in the step S3, the target reaction environment temperature is set while controlling the pressure to be 5000Pa-20000Pa; preferably 10000Pa-16000Pa, and optimally 15000Pa.
[0031] Preferably, the introduction rate of the tantalum source precursor in the step S3 is 0.5 g / min-150 g / min; more preferably 1 g / min-100 g / min; most preferably 30 g / min.
[0032] Preferably, the introduction time of the tantalum source precursor in the step S3 is 1 min-60 min; more preferably 5 min-50 min; most preferably 30 min.
[0033] Preferably, the carrier gas is hydrogen and argon.
[0034] Preferably, in the step S3, hydrogen and tantalum source precursor are introduced simultaneously.
[0035] Preferably, the flow rate of hydrogen is 0.5slm-30slm; more preferably 1slm-20slm; most preferably 2slm.
[0036] Preferably, when the argon gas is introduced simultaneously with the hydrogen gas, the flow rate thereof is 0.1 slm-70 slm; more preferably 1 slm-50 slm; most preferably 5 slm.
[0037] When the introduction of hydrogen stops, the flow rate of argon is adjusted to keep the gas introduction amount constant; the introduction time of argon in this stage is 1 min-40 min; more preferably 5 min-50 min; most preferably 10 min.
[0038] Preferably, the tantalum source precursor includes at least one of tantalum pentachloride, tantalum pentafluoride and tantalum pentabromide; more preferably tantalum pentachloride.
[0039] The present invention further limits the process conditions of the alternating deposition coating, especially limits the concentration of the tantalum source precursor in the gas phase precursor mixture, which improves the utilization rate of the tantalum source precursor on the one hand and optimizes the gas molecule diffusion process on the other hand, which can significantly accelerate the growth rate of the coating. The current process conditions are 2*10 -4mol / L concentration, the gas phase nucleation phenomenon is very obvious. The improved process of the present invention is 1*10 -3 mol / L, there is still no obvious gas phase nucleation phenomenon, which shows that the probability of gas phase nucleation particles being wrapped inside the coating is reduced and the coating quality is improved.
[0040] Preferably, the interval time between step S2 and step S3 is 0.5 min-30 min; more preferably, the interval time is 1 min-15 min; most preferably, the interval time is 10 min.
[0041] Preferably, the alternating deposition coating process further comprises S4. subjecting the tantalum carbide coating to a heat preservation reaction.
[0042] Preferably, the temperature of the insulation reaction is 1500° C.-2800° C., the pressure of the insulation reaction is 5 Pa-120000 Pa, and the time of the insulation reaction is 0.5 h-5 h.
[0043] More preferably, the temperature of the insulation reaction is 2000° C.-2500° C., the pressure of the insulation reaction is 10 Pa-100000 Pa, and the time of the insulation reaction is 1 h-3 h.
[0044] Most preferably, the temperature of the insulation reaction is 2500° C., the pressure of the insulation reaction is 50000 Pa, and the time of the insulation reaction is 2 hours.
[0045] A second aspect of the present invention provides a tantalum carbide coating prepared by the process described above, wherein the roughness of the tantalum carbide coating is less than 2 μm.
[0046] Preferably, the surface roughness of the tantalum carbide coating is less than 1 μm; more preferably, the surface roughness of the tantalum carbide coating is less than 0.8 μm.
[0047] Beneficial effects:
[0048] The alternating deposition coating process provided by the present invention has the following advantages:
[0049] (1) The present invention adopts a CVD method to provide a new tantalum carbide coating process. By separating the deposition processes of the carbon source precursor and the tantalum source precursor in time, the gas phase nucleation phenomenon is suppressed while the waste of the tantalum source precursor caused by the induced gas phase nucleation of the tantalum source precursor is effectively reduced. The utilization efficiency of the tantalum source precursor is significantly improved, which not only improves the quality of the tantalum carbide coating, but also greatly reduces the material cost.
[0050] (2) The alternating deposition plating process of the present invention is flexible in operation and can repeat the carbon deposition and tantalum deposition in a cycle according to the target thickness requirement. The carbon deposition and tantalum deposition conditions in each cycle can be independently adjusted according to the process requirements, and the controllability is strong.
[0051] (3) The present invention further controls the coating sequence to be substrate-carbon coating-tantalum coating-...-tantalum coating. On the one hand, starting from the carbon coating, the deposited carbon can be used as a buffer layer between the tantalum carbide coating and the substrate (such as graphite), thereby reducing the problem of easy peeling of the coating caused by the sudden change in the thermal expansion coefficient between the coating and the substrate material, and improving the adhesion between the coating and the substrate; on the other hand, the coating is terminated at the tantalum coating, thereby avoiding the defects of easy adsorption of impurities by the deposited carbon and low density of the coating; controlling the coating to terminate at the tantalum coating gives the coating excellent surface flatness and density, thereby significantly improving the quality of the product.
[0052] (4) The present invention can optimize the gas molecule diffusion process in the vapor deposition process by controlling the coating process conditions, especially the carbon coating process, the tantalum coating process and the final insulation conditions, so that the coating is dense and uniform. The improved process is 1*10 -3 mol / L, there is still no obvious gas phase nucleation phenomenon, which shows that the probability of gas phase nucleation particles encapsulated in the coating is reduced, and the coating quality is improved. The roughness of the final tantalum carbide coating can be reduced to below 2μm, which is significantly lower than the roughness level of the tantalum carbide coating prepared by the traditional process; and the overall process is simple and easy to operate, convenient for batch operation, and highly practical.
[0053] (5) After the present invention solves the gas phase nucleation problem, the powder contaminants on the sample surface are significantly reduced, and the subsequent sample processing is significantly simplified, which provides great convenience for the processing operation of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS
[0054] Figure 1 .SEM image of the tantalum carbide coating prepared in Example 1;
[0055] Figure 2 . SEM image of the tantalum carbide coating prepared in Example 2;
[0056] Figure 3 . SEM image of the tantalum carbide coating prepared in Example 3;
[0057] Figure 4 . Comparison diagram of the reaction chamber after preparing tantalum carbide coating in Example 1 and Comparative Example 1 (left: Example 1, right: Comparative Example 1);
[0058] Figure 5 .Comparison diagram of samples after preparing tantalum carbide coating in Example 1 and Comparative Example 1 (left: Example 1, right: Comparative Example 1). DETAILED DESCRIPTION
[0059] The present invention adopts a CVD method to provide a new tantalum carbide coating process.
[0060] The traditional technical means simultaneously introduces precursors such as propylene, hydrogen, and TaCl5 to form a tantalum carbide coating under certain temperature and pressure conditions. In this process, gas phase nucleation is prone to occur during the decomposition of carbon source precursors (such as propylene). It is well known that in the vapor deposition process, once a nucleation core is generated in the vapor phase precursor, the tantalum source precursor will nucleate in large quantities at the nucleation center under the process conditions. On the one hand, this phenomenon causes a large amount of tantalum source precursor to be wasted, greatly reducing the utilization efficiency of the tantalum source precursor; on the other hand, part of the black powder formed by vapor phase nucleation is not extracted and adheres to the surface of the sample, which has an adverse effect on the subsequent cleaning of the sample and the quality of the coating. The vapor phase nucleation particles are wrapped in the coating, which reduces the quality of the coating and the surface roughness of the coating is high.
[0061] In some embodiments of the present invention, the deposition processes of the carbon source precursor and the tantalum source precursor are separated in time, and the carbon source precursor is introduced first to form a uniform carbon coating layer on the surface of the component to be plated, so that it can fully react with the reduced tantalum; this solves the problem that when the tantalum source, carbon source and reducing gas are introduced together, the carbon source precursor undergoes gas phase nucleation, thereby inducing a large amount of tantalum source precursor to gas phase nucleate, resulting in uneven distribution and particle agglomeration. While suppressing the gas phase nucleation phenomenon, the waste of tantalum source precursor caused by the induced gas phase nucleation of tantalum source precursor is effectively reduced, and the utilization efficiency of tantalum source precursor is significantly improved, which not only improves the quality of tantalum carbide coating, but also greatly reduces material costs.
[0062] Example 1
[0063] This embodiment provides an alternating deposition coating process and a tantalum carbide coating, wherein the alternating deposition coating process comprises the following steps:
[0064] S1. Preheating the part to be plated: cleaning and drying the part to be plated (graphite part), and then transferring it to the reaction chamber, confirming that the air tightness of the reaction system meets the standard (the standard condition is that the pressure rise rate is stably lower than 25Pa / h), and then heating it to 850°C;
[0065] S2. When the temperature of the reaction chamber reaches 850°C and the pressure reaches 7000Pa, a carbon source precursor (propylene, C3H6) and a protective gas (argon) are introduced to perform carbon deposition on the surface of the component to be plated and form a carbon coating layer; wherein the flow rate of the propylene is 50sccm, and the flow rate of the argon is 5slm. After 20min, the introduction of the propylene and argon is stopped, and the pressure of the reaction chamber is reduced to below 300Pa;
[0066] S3. After stopping the introduction of propylene for 10 minutes, the reaction chamber temperature is set to 1600° C., the pressure is raised to 15000 Pa, and a tantalum source precursor (tantalum pentachloride) and a carrier gas (hydrogen and argon) vaporized at 260° C. are introduced to deposit tantalum on the surface of the part to be plated to form a tantalum-plated layer; wherein the introduction speed of the tantalum pentachloride is 30 g / min, the flow rate of the hydrogen is 2 slm, and the flow rate of the argon is 5 slm; after 30 minutes, the introduction of the hydrogen and tantalum pentachloride is stopped, and the argon flow rate is adjusted to 2 slm and maintained for 10 minutes before the introduction of argon is stopped;
[0067] S4. The tantalum carbide coating is subjected to a heat preservation reaction at a temperature of 2500° C., a pressure of 50000 Pa, and a time of 2 hours to obtain a tantalum carbide coating, and the coating process is completed.
[0068] The roughness of the tantalum carbide coating prepared in this embodiment is 0.61 μm; the SEM image of the tantalum carbide coating is shown in Figure 1 .
[0069] Example 2
[0070] This embodiment provides an alternating deposition coating process and a tantalum carbide coating, wherein the alternating deposition coating process comprises the following steps:
[0071] S1. Preheating the part to be plated: cleaning and drying the part to be plated (graphite part), and then transferring it to the reaction chamber, confirming that the air tightness of the reaction system meets the standard (the standard condition is that the pressure rise rate is stably lower than 25Pa / h), and then heating it to 1000°C;
[0072] S2. When the temperature of the reaction chamber reaches 1000°C and the pressure reaches 7000Pa, a carbon source precursor (propylene, C3H6) and a protective gas (argon) are introduced to perform carbon deposition on the surface of the component to be plated and form a carbon coating layer; wherein the flow rate of the propylene is 50sccm, and the flow rate of the argon is 5slm. After 20min, the introduction of the propylene and argon is stopped, and the pressure of the reaction chamber is reduced to below 300Pa;
[0073] S3. After stopping the introduction of propylene for 10 minutes, the reaction chamber temperature is set to 1600° C., the pressure is raised to 15000 Pa, and a tantalum source precursor (tantalum pentachloride) and a carrier gas (hydrogen and argon) vaporized at 260° C. are introduced to deposit tantalum on the surface of the part to be plated to form a tantalum-plated layer; wherein the introduction speed of the tantalum pentachloride is 30 g / min, the flow rate of the hydrogen is 2 slm, and the flow rate of the argon is 5 slm; after 30 minutes, the introduction of the hydrogen and tantalum pentachloride is stopped, and the argon flow rate is adjusted to 2 slm and maintained for 10 minutes before the introduction of argon is stopped;
[0074] S4. The tantalum carbide coating is subjected to a heat preservation reaction at a temperature of 2500° C., a pressure of 50000 Pa, and a time of 2 hours to obtain a tantalum carbide coating, and the coating process is completed.
[0075] The roughness of the tantalum carbide coating prepared in this embodiment is 0.63 μm; the SEM image of the tantalum carbide coating is shown in Figure 2 .
[0076] Example 3
[0077] This embodiment provides an alternating deposition coating process and a tantalum carbide coating, wherein the alternating deposition coating process specifically comprises the following steps:
[0078] S1. Preheating the part to be plated: cleaning and drying the part to be plated (graphite part), and then transferring it to the reaction chamber, confirming that the air tightness of the reaction system meets the standard (the standard condition is that the pressure rise rate temperature is lower than 25Pa / h), and then heating it to 850°C;
[0079] S2. When the temperature of the reaction chamber reaches 850°C and the pressure reaches 7000Pa, a carbon source precursor (propylene) and a protective gas (argon) are introduced to perform carbon deposition on the surface of the component to be plated and form a carbon coating layer; wherein the flow rate of the propylene is 50sccm, and the flow rate of the argon is 5slm. After 20min, the introduction of the propylene and argon is stopped, and the pressure of the reaction chamber is reduced to below 300Pa;
[0080] S3. After stopping the introduction of propylene for 10 minutes, the reaction chamber temperature is set to 1600° C., the pressure is raised to 15000 Pa, and a tantalum source precursor (tantalum pentachloride) and a carrier gas (hydrogen and argon) vaporized at 260° C. are introduced to deposit tantalum on the surface of the part to be plated to form a tantalum-plated layer; wherein the introduction speed of the tantalum pentachloride is 30 g / min, the flow rate of the hydrogen is 2 slm, and the flow rate of the argon is 5 slm; after 30 minutes, the introduction of the hydrogen and tantalum pentachloride is stopped, and the argon flow rate is adjusted to 7 slm and maintained for 10 minutes before the introduction of argon is stopped;
[0081] S4. Repeat step S2 to perform carbon deposition again;
[0082] S5. Repeat step S3 to deposit tantalum again;
[0083] S6. After 15 minutes after the completion of step S5, the tantalum carbide coating is subjected to a heat preservation reaction at a temperature of 2500° C., a pressure of 50000 Pa, and a time of 2 hours to obtain a tantalum carbide coating, and the coating process is completed.
[0084] The roughness of the tantalum carbide coating prepared in this embodiment is 0.57 μm; the SEM image of the tantalum carbide coating is shown in Figure 3 .
[0085] Comparative Example 1
[0086] This comparative example provides a conventional coating process and tantalum carbide coating, the steps comprising:
[0087] 1. Clean and dry the parts to be plated (graphite parts), then transfer them to the reaction chamber. After confirming that the air tightness of the reaction system meets the standard (the standard condition is that the pressure rise rate is stably lower than 25Pa / h), heat it to 1600℃;
[0088] 2. After the temperature of the reaction chamber reaches 1600°C and the pressure reaches 15000 Pa, argon, hydrogen, tantalum pentachloride and propylene gas are introduced, wherein the propylene flow rate is 50 sccm, the argon flow rate is 5 slm, the tantalum pentachloride introduction rate is 30 g / min, and the hydrogen flow rate is 2 slm; after 30 minutes, the introduction of hydrogen, propylene and tantalum pentachloride is stopped, and the argon flow rate is adjusted to 2 slm;
[0089] 3. Adjust the argon flow rate to 2slm and keep it for 15 minutes, then stop the argon flow and the process is completed.
[0090] The roughness of the tantalum carbide coating prepared in this comparative example is 2.13 μm.
[0091] Comparative Example 2
[0092] This comparative example provides a conventional coating process and tantalum carbide coating, the steps comprising:
[0093] 1. Clean and dry the parts to be plated (graphite parts), then transfer them to the reaction chamber. After confirming that the air tightness of the reaction system meets the standard (the standard condition is that the pressure rise rate is stably lower than 25Pa / h), heat it to 1250℃;
[0094] 2. After the temperature of the reaction chamber reaches 1250°C and the pressure reaches 15000 Pa, argon, hydrogen, tantalum pentachloride and propylene gas are introduced, wherein the propylene flow rate is 50 sccm, the argon flow rate is 5 slm, the tantalum pentachloride introduction rate is 30 g / min, and the hydrogen flow rate is 2 slm; after 30 minutes, the introduction of hydrogen, propylene and tantalum pentachloride is stopped, and the argon flow rate is adjusted to 2 slm;
[0095] 3. Adjust the argon flow rate to 2slm and keep it for 15 minutes, then stop the argon flow and the process is completed.
[0096] Comparative Example 3
[0097] This comparative example provides an alternating deposition coating process and a tantalum carbide coating, wherein the alternating deposition coating process comprises the following steps:
[0098] 1. Preheat the parts to be plated: clean and dry the parts to be plated (graphite parts), then transfer them to the reaction chamber, confirm that the air tightness of the reaction system meets the standard (the standard condition is that the pressure rise rate is stably lower than 25Pa / h), and then heat them to 1200°C;
[0099] 2. When the temperature of the reaction chamber reaches 1200°C and the pressure reaches 7000Pa, a carbon source precursor (propylene, C3H6) and a protective gas (argon) are introduced to perform carbon deposition on the surface of the component to be plated and form a carbon coating layer; wherein the flow rate of the propylene is 50sccm, and the flow rate of the argon is 5slm. After 20 minutes, the introduction of the propylene and argon is stopped, and the pressure of the reaction chamber is reduced to below 300Pa;
[0100] 3. After stopping the introduction of propylene for 10 minutes, the temperature of the reaction chamber is set to 1600° C., the pressure is raised to 15000 Pa, and a tantalum source precursor (tantalum pentachloride) vaporized at 260° C. and a carrier gas (hydrogen and argon) are introduced to deposit tantalum on the surface of the component to be plated to form a tantalum coating; wherein the introduction rate of the tantalum pentachloride is 30 g / min, the flow rate of the hydrogen is 2 slm, and the flow rate of the argon is 5 slm; after 30 minutes, the introduction of the hydrogen and tantalum pentachloride is stopped, the argon flow rate is adjusted to 2 slm and maintained for 10 minutes, and then the introduction of argon is stopped;
[0101] 4. The tantalum carbide coating is subjected to a heat preservation reaction at a temperature of 2500° C., a pressure of 50000 Pa, and a time of 2 hours to obtain a tantalum carbide coating, and the coating process is completed.
[0102] Performance Testing
[0103] 1. Roughness
[0104] The roughness of the tantalum carbide coatings of Examples 1 to 3 and Comparative Examples 1 to 3 was measured using a Jitai TR100 surface roughness tester, and the measurement results were taken as the average of multiple point tests; the test results are shown in Table 1. It can be seen from Table 1 that the roughness of the tantalum carbide coating obtained by the alternating deposition coating process of the present invention is significantly reduced compared with the traditional process, and the surface smoothness of the tantalum carbide coating is improved.
[0105] Table 1
[0106] sample Roughness(μm) Example 1 0.61 Example 2 0.63 Example 3 0.57 Comparative Example 1 2.13 Comparative Example 2 2.21 Comparative Example 3 2.15
[0107] 2. SEM images
[0108] Example 1 SEM image of tantalum carbide coating Figure 1 The thickness of the single coating in Example 1 is about 10 μm. The SEM image of the tantalum carbide coating in Example 2 is shown in FIG. Figure 2The thickness of the single coating in Example 2 is about 10 μm. The SEM image of the tantalum carbide coating in Example 3 is shown in FIG. Figure 3 In Example 3, after 2 cycles, the coating thickness is about 20 μm.
[0109] from Figure 1-3 It can be seen that no gas phase nucleation phenomenon occurs inside the tantalum carbide coating obtained by the alternating deposition coating process of the present invention, and the coating quality is significantly improved.
[0110] 3. Comparison of particle agglomeration
[0111] The implementation of Example 1 and Comparative Example 1 were compared, and the particle agglomeration and gas phase nucleation trend were judged by observing the reaction chamber and the surface of the coating after the process was completed; the comparison diagrams are shown in FIG. Figure 4 , 5 ; Figure 4 , 5 In the figures, the left figure corresponds to Example 1, and the right figure corresponds to Comparative Example 1. It can be seen from the figures that after the tantalum carbide coating is prepared by the traditional preparation process in Comparative Example 1, a large amount of black powder (particles precipitated after gas phase nucleation) can be seen with the naked eye covering the crucible and the sample surface, reflecting serious particle agglomeration and obvious gas phase nucleation trend. After the process of Example 1, the reaction chamber and the sample surface are clean and bright, without any black powder, which proves that the preparation process of the present invention can significantly inhibit the gas phase nucleation of the carbon source and induce the gas phase nucleation trend of the tantalum source, and finally there is no problem of particle agglomeration and black powder covering the crucible and the sample surface.
Claims
1. An alternating deposition coating process, characterized in that: The alternating deposition plating process comprises: providing a component to be plated, and performing carbon deposition and tantalum deposition on the surface of the component to be plated, respectively, to obtain a tantalum carbide plating layer.
2. The alternating deposition coating process according to claim 1, characterized in that: The steps of respectively depositing carbon and tantalum on the surface of the component to be plated include: S1. Preheating the part to be plated; S2. Carbon deposition is performed on the surface of the component to be plated to form a carbon coating layer; S3. Performing tantalum deposition on the carbon-plated layer to form a tantalum-plated layer, so as to obtain a tantalum carbide plating layer on the surface of the component to be plated.
3. The alternating deposition coating process according to claim 2, characterized in that: The steps S2 and S3 are repeatedly cycled until the thickness of the tantalum carbide coating reaches a target thickness, and the number of the cycle operations is an even number; the target thickness is 10 μm-20 μm.
4. The alternating deposition coating process according to claim 2, characterized in that: The step S2 includes: setting the reaction environment temperature to 600° C.-1000° C., introducing a carbon source precursor and a protective gas to perform carbon deposition.
5. The alternating deposition coating process according to claim 4, characterized in that: In the step S2, the introduction time of the carbon source precursor is 1 min-60 min, and the flow rate of the carbon source precursor is 10 sccm-800 sccm.
6. The alternating deposition coating process according to claim 1, characterized in that: The carbon source precursor has the general structural formula of C x H y , where 1≤x≤5, 2≤y≤8.
7. The alternating deposition coating process according to claim 2, characterized in that: The step S3 includes: setting the reaction environment temperature to 1050° C.-2400° C., introducing a tantalum source precursor and a carrier gas to perform tantalum deposition.
8. The alternating deposition coating process according to claim 7, characterized in that: In the step S3, the introduction rate of the tantalum source precursor is 0.5 g / min-150 g / min, and the introduction time is 1 min-60 min.
9. The alternating deposition coating process according to claim 2, characterized in that: Also includes: S4. The tantalum carbide coating is subjected to a heat preservation reaction; Wherein, the temperature of the insulation reaction is 1500°C-2800°C, the pressure of the insulation reaction is 5Pa-120000Pa, and the time of the insulation reaction is 0.5h-5h.
10. A tantalum carbide coating prepared by the process according to any one of claims 1 to 9, characterized in that: The surface roughness of the tantalum carbide coating is less than 2 μm.