A method for producing a multicomponent chemical vapor deposition diffusion-type aluminide coating

Abstract

The application provides a method for preparing a diffusion type aluminide compound coating by multi-component chemical vapor deposition, relates to the technical field of high-temperature protective coating preparation, and can realize co-deposition of multiple active elements or alloying elements and aluminum elements and accurate control of a deposition content; the application can realize control of different reaction temperatures and reaction pressures; the application can realize co-deposition of active elements at different aluminizing times, and co-deposition can occur at the beginning, middle or end of reaction according to different process parameters; and the coating prepared by the application is uniform in composition and has few internal defects.

Description

Technical Field

[0001] This invention relates to the field of high-temperature protective coating preparation technology, specifically to a method for preparing diffusion-type aluminide coatings by multi-electrochemical vapor deposition. Background Technology

[0002] The service performance of hot-end components in aero-engines directly determines the engine's thrust-to-weight ratio, fuel efficiency, and service life. With the continuous increase in engine thrust and turbine inlet temperature, traditional metal protective coatings are gradually revealing their insufficient service life under high-temperature oxidation and hot corrosion environments. For turbine blades, in addition to the outer surface, the blade cavity is also subjected to a complex service environment of high temperature, high stress, and corrosive atmosphere for extended periods. This is especially true for double-walled blades with multiple film-forming pores and complex cooling channel structures, where the protection of the internal cavity is particularly critical. When using traditional embedding infiltration or vapor-phase infiltration processes to prepare aluminide coatings, it is often difficult to achieve uniform coverage of the complex internal cavity structure, easily leading to coating gaps or component segregation in localized areas, thereby inducing failure problems such as internal cavity corrosion and substrate perforation.

[0003] Chemical vapor deposition (CVD) technology has become an important method for preparing high-temperature protective coatings for aero-engine blades due to its excellent gas-phase transport capabilities and compositional controllability. By introducing active or alloying elements into CVD aluminide coatings, oxide film grains can be effectively refined, sulfur diffusion can be suppressed, and oxide film adhesion can be improved, thereby significantly enhancing the high-temperature service performance of the coating. However, in existing technologies, doping elements are mostly introduced in a single or non-synergistic manner, making it difficult to achieve uniform deposition of multiple elements within complex cavities. The compositional consistency and stability of the prepared coatings still need to be improved.

[0004] Therefore, there is an urgent need for a diffusion-type aluminide coating preparation method that can achieve the synergistic introduction of multiple elements, controllable process parameters, and is applicable to complex internal cavity structures. Summary of the Invention

[0005] In view of the above problems, this invention proposes a method for preparing diffusion-type aluminide coatings by multi-element chemical vapor co-deposition. The aim is to achieve the simultaneous deposition and diffusion of aluminum and at least one active element on the substrate surface, forming a high-temperature protective coating with uniform composition, strong bonding and excellent performance. This method achieves stable control of coating composition and thickness, improves process repeatability, and is suitable for coating preparation of high-temperature alloy components of aero-engines, especially complex internal cavity structure surfaces.

[0006] This invention provides a method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition, comprising: Step 1: In the chemical vapor deposition equipment, a low-temperature reaction zone for aluminum source, a medium-temperature reaction zone for active elements, and a deposition zone are set up respectively; the low-temperature reaction zone for aluminum source and the medium-temperature reaction zone for active elements are connected to the deposition zone through gas channels respectively; Optionally, the chemical vapor deposition equipment includes a main pipe that leads directly to the deposition zone, a low-temperature zone channel 7, and a medium-temperature zone channel 6, each with its own independent access. The main pipeline directly leading to the deposition zone is an independent H2 input pipeline, providing the hydrogen gas required for the reduction reaction; its function is to reduce AlCl3 / ZrCl4: AlCl3 + 3 / 2 H2 → Al + 3HCl ZrCl4 + 2H2 → Zr + 4HCl; and to regulate the total pressure in the deposition zone. The low-temperature channel 7 first passes through the low-temperature reaction zone, where Ar, H2 and HCl are introduced. Its functions are: to carry HCl to react with Al to generate AlCl3; and to use Ar / H2 as a carrier gas to deliver AlCl3 into the deposition zone. The intermediate temperature channel 6 first passes through the intermediate temperature reaction zone, through which Ar, H2 and HCl are introduced. Its functions are: to carry HCl to react with Zr / Hf to generate ZrCl4 / HfCl4; and to use Ar / H2 as a carrier gas to deliver the metal chloride into the deposition zone.

[0007] Step 2: Place the aluminum source material in the low-temperature reaction zone of the aluminum source, place at least one active element source material in the medium-temperature reaction zone of the active element, and fix the metal substrate to be treated in the deposition zone. Step 3: Introduce carrier gas and reaction gas into the low-temperature reaction zone of the aluminum source and the medium-temperature reaction zone of the active element, respectively; Based on the thermodynamic-kinetic coupling model, the temperature of the low-temperature reaction zone of the aluminum source, the temperature of the medium-temperature reaction zone of the active element, the temperature of the deposition zone, the flow rate of the carrier gas and the reaction gas in each reaction zone, the deposition time and the deposition pressure are respectively controlled to achieve the control of the doping content of the active element and obtain the controlled aluminum-containing gas phase and the active element-containing gas phase. Aluminum-containing gas phase and active element-containing gas phase migrate to the surface of the metal substrate and undergo simultaneous co-deposition and diffusion reactions to form an element-doped diffusion-type aluminide coating.

[0008] Optionally, the diffusion-type aluminide coating includes a Zr-doped aluminide coating, an interdiffusion region, and a high-temperature alloy substrate.

[0009] Optionally, the main phase of the diffusion-type aluminide coating is aluminide, and the second phase is a small amount of active elements.

[0010] Optionally, the aluminum source is high-purity metallic aluminum particles or a compound that can generate an aluminum-containing gas phase during the reaction process, placed in the low-temperature reaction zone of the aluminum source, and supported by a graphite labyrinth structure.

[0011] Preferably, the filling volume of the aluminum particles is 3 / 4 to 4 / 5 of the volume of the low-temperature reaction chamber; The aluminum particles are cylindrical particles with a diameter of φ6x6mm or φ3x3mm.

[0012] Optionally, the carrier gas is Ar; the reactant gases are H2 and HCl.

[0013] Optionally, the reaction temperature in the low-temperature reaction zone of the aluminum source is 300–600℃, and the reaction temperature in the medium-temperature reaction zone of the active element is 100–500℃; the deposition temperature is 600–1200 °C, the deposition pressure is 5–60 kPa, the heating rate is 5–20℃ / min, and the deposition time is 60–150 min. Optionally, the deposition time includes the co-deposition time of active elements and the deposition time of single aluminum; The ratio of co-deposition time to deposition time of active elements is 0.02-0.2:1, in order to achieve effective doping of active elements and avoid their excessive aggregation.

[0014] For example, graphite paper is laid in the graphite component structure of a graphite maze, and aluminum particles are evenly laid on the surface of the graphite paper.

[0015] Optionally, the low-temperature reaction zone of the aluminum source and the medium-temperature reaction zone of the active element in step 1 are respectively provided with independent gas guiding channels to achieve effective control of the atmosphere in different reaction zones.

[0016] Optionally, the active element is Zr, Hf, Y, Dy, Ce and / or La; Optionally, step 3 also includes gas scrubbing, the specific steps of which include: Ar gas is introduced into the reaction chamber, and after evacuating to 5-20 kPa, Ar gas is introduced again. This process is repeated 2-5 times. The furnace was pumped down to 1-10 Pa using a mechanical pump, and Ar gas was then introduced back in.

[0017] Optionally, the H2 carrier gas flow rate in the main pipeline is 1-10 SLM; The ratio of Ar gas, H2 gas, and HCl gas flow rates in the low-temperature reaction zone is 0-5:0-5:0-1; The ratio of Ar gas, H2 gas, and HCl gas flux in the mesophilic reactor is 0-5:0-5:0-1.

[0018] Optionally, step 3 includes a heating stage, a co-deposition stage, and a single aluminum deposition stage; During the heating phase, adjust the H2 carrier gas flow rate in the main pipeline to 0.5-2 SLM; The ratio of Ar, H2, and HCl gas flow rates in the low-temperature reaction zone is 1-5:0.5-2:0; The ratio of Ar gas, H2 gas, and HCl gas flux in the mesophilic reactor is 0.5-3:0.5-2:0; During the co-deposition stage, the H2 flux in the main pipeline is adjusted to 2-6 SLM; The ratio of Ar, H2, and HCl gas flow rates in the low-temperature reaction zone is 0-2:1-5:0.05-0.5; The ratio of Ar, H2, and HCl gas fluxes in the mesophilic reactor is 0-3:0-2:0.1-0.8. During the single aluminum deposition stage, adjust the H2 flux in the main pipeline to 3-8 SLM; The ratio of Ar gas, H2 gas, and HCl gas flow rates in the low-temperature reaction zone is 0-2 : 2-5 : 0.2-1.0; The ratio of Ar gas, H2 gas, and HCl gas flux in the mesophilic reactor is 0-2:0-3:0.

[0019] In this invention, the active element is placed in the form of particles in multiple high-temperature resistant reaction vessels. The multiple high-temperature resistant reaction vessels are placed in the medium-temperature reaction zone of the active element in sequence. The uppermost and lowermost containers do not contain active elements to ensure smooth gas flow.

[0020] Optionally, the high-temperature resistant reaction vessel in step 2 is made of stainless steel, nickel, or graphite, with a diameter smaller than that of the pipe in the medium-temperature reaction zone. The active element particles are spread in 1-2 layers in the high-temperature resistant reaction vessel to avoid airflow blockage and ensure reaction uniformity.

[0021] Optionally, the thermodynamic-dynamic coupling model expression is:

[0022] in, J i For elements i Depositing molar flux on the substrate surface k i For elements i Constants related to reaction kinetics P i For elements i The effective partial pressure in the reaction zone, n It is the reaction order. Q i For elements i The apparent activation energy of the reaction T The reaction temperature. R is the gas constant.

[0023] The expression for the atomic percentage of aluminum or active elements in the coating is:

[0024] The expression for the mass percentage of aluminum or active elements in the coating is:

[0025] in, M i For elements i molar mass, For elements i The percentage of atoms in the coating. For elements i Molar flux of deposition on the substrate surface Represents the total depositional molar flux. Represents element i Percentage by mass in the coating This represents the total mass deposition flux.

[0026] In multi-element co-deposition processes, the content of each element in the coating is determined by its corresponding vapor deposition flux. Deposition flux is related to reaction temperature, reactant gas partial pressure, and reaction kinetic parameters. By adjusting the amount of different element sources added, the carrier gas flow rate, and the reaction zone temperature, the deposition flux ratio of each element can be controlled, thereby achieving precise control over the atomic or mass fraction of each element in the coating. For the doping of two or more active elements, the reaction temperature corresponding to the same reaction rate is first determined based on the halogenation reaction, and then the doping ratio is determined based on the content of each element placed in the high-temperature resistant reaction vessel.

[0027] This invention enables the co-deposition of aluminum and active or alloying elements during chemical vapor deposition, achieving stable control of coating composition and thickness, and improving process repeatability.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The present invention can achieve co-deposition of multiple active elements or alloying elements and aluminum elements, and achieve precise control of the deposition content; (2) The present invention can achieve control over different reaction temperatures and reaction pressures; (3) The present invention can achieve co-deposition of active elements at different aluminizing times. Co-deposition can occur at the beginning, middle or end of the reaction depending on different process parameters. (4) The coating prepared by the present invention has a uniform composition and fewer internal defects. Attached Figure Description

[0029] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0030] Figure 1This is a schematic diagram of the chemical vapor deposition equipment used in the embodiments of the present invention; Figure 2 This is a schematic diagram of the structure of the intermediate-temperature reaction zone for active elements in an embodiment of the present invention; Figure 3 This is a schematic diagram of the temperature selection curve for controlling the doping content when two or more active elements are co-deposited in an embodiment of the present invention; Figure 4 This is a schematic diagram of the cross-sectional morphology of the coating prepared in Example 1 of the present invention; Figure 5 This is a schematic diagram of the cross-sectional morphology of the coating prepared in Example 2 of the present invention.

[0031] In the diagram: 1-Heating furnace, 2-Sample rack, 3-Graphite maze, 4-Medium temperature reaction zone, 5-Low temperature reaction zone, 6-Gas channel of medium temperature reaction chamber, 7-Gas channel of low temperature reaction chamber, 8-High temperature resistant reaction vessel, 9-Ventilation hole, 10-Gas pipeline, 11-First type of active element particles, 12-Second type of active element particles. Detailed Implementation

[0032] To better understand the above-described objectives, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other. Furthermore, the present invention can be implemented in other ways different from those described herein; therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0033] A specific embodiment of the present invention, such as Figure 1-5 A method for preparing a diffusion-type aluminide coating by multi-dimensional chemical vapor co-deposition is disclosed. Example 1 A method for preparing diffusion-type aluminide coatings by multi-electrochemical vapor deposition includes the following steps: Step 1: Select high-purity aluminum particles with a size of φ6mm × 6mm as the aluminum source and spread them evenly on the surface of the graphite base plate inside the graphite labyrinth 3 in the reaction chamber of the heating furnace 1. Aluminum particles are placed in the low-temperature reaction zone 5, with the volume of aluminum particles accounting for 3 / 4 of the total volume of the reactor. Step 2: Select high-purity Zr particles with a size of φ2mm × 5mm as the active element source. The intermediate temperature reaction zone 4 includes multiple high-temperature resistant reaction vessels 8 made of graphite material arranged equidistantly from top to bottom; High-purity Zr particles are evenly spread in the middle of multiple high-temperature resistant reaction vessels made of graphite material in the intermediate temperature reactor. Two layers of high-purity Zr particles are spread in each high-temperature reaction vessel. The top and bottom layers do not contain active elements to ensure smooth flow of reaction gases; Step 3: Fix the high-temperature alloy substrate, which has been mechanically ground, sandblasted and cleaned, onto the sample holder 2 and place it in the deposition zone inside the heating furnace; Ar gas is introduced into the reaction chamber of the heating furnace, and after being evacuated to 8 kPa, Ar gas is introduced again to purify the atmosphere of the furnace chamber. This process is repeated 5 times. The furnace was pumped down to 5 Pa using a mechanical pump, and Ar gas was reintroduced. Open the gas valve and adjust the H2 carrier gas flow rate in the main pipeline to 1 SLM. In the cryogenic reactor, the Ar gas flow rate is 3 SLM, the H2 carrier gas flow rate is 1 SLM, and the HCl carrier gas flow rate is 0 SLM. In the mesophilic reactor, the Ar gas flux was 1 SLM, the H2 carrier gas flux was 1 SLM, and the HCl carrier gas flux was 0 SLM, with the pressure stabilized at 20 kPa. The temperature inside the furnace was raised to 1050 °C at a heating rate of 10 °C / min, the temperature in the low-temperature reaction zone was raised to 300 °C, and the temperature in the medium-temperature reaction zone was raised to 400 °C, and then held for 20 min. The H2 flux in the main pipeline was adjusted to 3 SLM. In the low-temperature reaction zone, the Ar flux was 0 SLM, the H2 carrier gas flux was 3 SLM, and the HCl carrier gas flux was 0.1 SLM. In the medium-temperature reaction zone, the Ar flux was 2 SLM, the H2 flux was 0 SLM, and the HCl carrier gas flux was 0.2 SLM. The pressure was stabilized at 20 kPa and held for 20 min to achieve the co-deposition of Al and Zr elements. The H2 flux in the main pipeline was adjusted to 5 SLM, the Ar flux in the low-temperature reaction zone was 0 SLM, the H2 carrier gas flux was 3 SLM, and the HCl carrier gas flux was 0.5 SLM, and the Ar flux in the medium-temperature reaction zone was 0 SLM, the H2 flux was 2 SLM, and the HCl carrier gas flux was 0 SLM. The pressure was stabilized at 20 kPa and held for 120 min to achieve single Al element deposition. After the entire process is completed, sample one is obtained. Sample one is then removed, and the following is obtained: Figure 4 The coating morphology shown is divided into three parts: Zr-doped aluminum oxide coating, interdiffusion region, and high-temperature alloy substrate. According to the composition analysis, the coating composition of sample one is Ni-35.68Al-0.51Zr (wt.%).

[0034] Example 2 A method for preparing diffusion-type aluminide coatings by multi-electrochemical vapor deposition includes the following steps: Step 1: Select high-purity aluminum particles with a size of φ6mm × 6mm as the aluminum source and lay them flat on the surface of the graphite component chassis inside the graphite labyrinth. Aluminum particles are placed in the low-temperature reaction zone, with the volume of aluminum particles occupying approximately 4 / 5 of the total reactor volume. Step 2: Select high-purity Zr particles with a diameter of 2mm × 5mm and high-purity Hf particles with a diameter of 1mm × 5mm; Zr particles were laid at the bottom of four high-temperature resistant reaction vessels made of graphite material, and Hf particles were laid on top of them; no active element particles were placed in the top and bottom containers to ensure smooth flow of reaction gas. Step 3: Place the high-temperature alloy substrate, which has undergone pretreatment processes such as mechanical grinding, sandblasting, and cleaning, on the sample holder and place it in the heating furnace; First, fill the equipment with Ar gas, then evacuate it to 8 kPa, and then fill it with Ar gas again to clean the atmosphere inside the furnace. Repeat this process 3 times. Then, use a mechanical pump to evacuate it to 7 Pa and fill it with Ar gas. Open the gas valve and adjust the H2 flux in the main pipeline to 1 SLM, the Ar flux in the low-temperature reaction zone to 3 SLM, the H2 carrier gas flux to 1 SLM, and the HCl carrier gas flux to 0 SLM, and the Ar flux to 1 SLM, the H2 flux to 1 SLM, and the HCl carrier gas flux to 0 SLM in the medium-temperature reaction zone; stabilize the pressure at 20 kPa. The temperature inside the furnace was raised to 1000 °C at a heating rate of 10 °C / min, the temperature in the low-temperature reaction zone was raised to 320 °C, and the temperature in the medium-temperature reaction zone was raised to 450 °C, and held for 20 min. The H2 flux in the main pipeline was adjusted to 5 SLM, the Ar flux in the low-temperature reaction zone was 0 SLM, the H2 carrier gas flux was 3 SLM, and the HCl carrier gas flux was 0.5 SLM, and the Ar flux in the medium-temperature reaction zone was 0 SLM, the H2 flux was 3 SLM, and the HCl carrier gas flux was 0 SLM. The pressure was stabilized at 20 kPa and held for 120 min to achieve single Al element deposition.

[0035] The H2 flux in the main pipeline was adjusted to 3 SLM, the Ar flux in the low-temperature reaction zone was 0 SLM, the H2 carrier gas flux was 3 SLM, and the HCl carrier gas flux was 0.2 SLM, and the Ar flux in the medium-temperature reaction zone was 2 SLM, the H2 flux was 0 SLM, and the HCl carrier gas flux was 0.4 SLM. The pressure was stabilized at 20 kPa and held for 30 min to achieve the co-deposition of Al, Zr, and Hf elements. After the entire process is completed, sample two is obtained. Sample two is then removed, and the following is obtained: Figure 5The coating morphology shown is divided into three parts: Zr and Hf doped aluminum oxide coating, interdiffusion region, and high-temperature alloy substrate. Composition analysis revealed that the coating composition of sample two was Ni-32.90Al-1.79Zr-0.193Hf (wt.%).

[0036] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition, characterized in that, include: Step 1: In the chemical vapor deposition equipment, a low-temperature reaction zone for aluminum source, a medium-temperature reaction zone for active elements, and a deposition zone are set up respectively; the low-temperature reaction zone for aluminum source and the medium-temperature reaction zone for active elements are connected to the deposition zone through gas channels respectively; Step 2: Place the aluminum source material in the low-temperature reaction zone of the aluminum source, place at least one active element source material in the medium-temperature reaction zone of the active element, and fix the metal substrate to be treated in the deposition zone. Step 3: Introduce carrier gas and reaction gas into the low-temperature reaction zone of the aluminum source and the medium-temperature reaction zone of the active element, respectively; Based on the thermodynamic-kinetic coupling model, the temperature of the low-temperature reaction zone of the aluminum source, the temperature of the medium-temperature reaction zone of the active element, the temperature of the deposition zone, the flow rate of the carrier gas and the reaction gas in each reaction zone, the deposition time and the deposition pressure are respectively controlled to achieve the control of the doping content of the active element and obtain the controlled aluminum-containing gas phase and the active element-containing gas phase. Aluminum-containing gas phase and active element-containing gas phase migrate to the surface of the metal substrate and undergo simultaneous co-deposition and diffusion reactions to form an element-doped diffusion-type aluminide coating.

2. The method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition according to claim 1, characterized in that, The carrier gas is Ar; the reactant gases are H2 and HCl.

3. The method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition according to claim 2, characterized in that, The chemical vapor deposition equipment includes a main pipeline that directly leads to the deposition zone, a low-temperature zone channel (7), and a medium-temperature zone channel (6). The main pipeline directly leading to the deposition zone is an independent H2 input pipeline, providing the hydrogen required for the reduction reaction and regulating the total pressure in the deposition zone; Ar, H2 and HCl are introduced into the low-temperature channel (7), carrying HCl to react with Al to generate AlCl3; Ar / H2 is used as a carrier gas to deliver AlCl3 into the deposition zone; Ar, H2 and HCl are introduced into the medium temperature channel (6), and HCl is carried to react with Zr / Hf to generate ZrCl4 / HfCl4; Ar / H2 is used as a carrier gas to deliver the metal chloride into the deposition zone.

4. The method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition according to claim 1, characterized in that, The reaction temperature in the low-temperature reaction zone of the aluminum source is 300–600℃, and the reaction temperature in the medium-temperature reaction zone of the active elements is 100–500℃.

5. The method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition according to claim 1, characterized in that, The temperature in the deposition zone was 600-1200 °C, the deposition pressure was 5-60 kPa, and the deposition time was 60-150 min.

6. The method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition according to claim 1, characterized in that, The active elements are Zr, Hf, Y, Dy, Ce and / or La.

7. The method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition according to claim 3, characterized in that, The H2 carrier gas flow rate in the main pipeline is 1-10 SLM; The ratio of Ar gas, H2 gas, and HCl gas flow rates in the low-temperature reaction zone is 0-5:0-5:0-1; The ratio of Ar gas, H2 gas, and HCl gas flux in the mesophilic reactor is 0-5:0-5:0-1.

8. The method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition according to claim 1, characterized in that, The thermodynamic-dynamic coupling model is expressed as follows: in, J i For elements i Depositing molar flux on the substrate surface k i For elements i Constants related to reaction kinetics P i For elements i The effective partial pressure in the reaction zone, n It is the reaction order. Q i For elements i The apparent activation energy of the reaction T The reaction temperature. R is the gas constant.

9. The method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition according to claim 1, characterized in that, Step 3 includes the heating stage, the co-deposition stage, and the single aluminum deposition stage; During the heating phase, adjust the H2 carrier gas flow rate in the main pipeline to 0.5-2 SLM; The ratio of Ar, H2, and HCl gas flow rates in the low-temperature reaction zone is 1-5:0.5-2:0; The ratio of Ar gas, H2 gas, and HCl gas flux in the mesophilic reactor is 0.5-3:0.5-2:0; During the co-deposition stage, the H2 flux in the main pipeline is adjusted to 2-6 SLM; The ratio of Ar, H2, and HCl gas flow rates in the low-temperature reaction zone is 0-2:1-5:0.05-0.5; The ratio of Ar, H2, and HCl gas fluxes in the mesophilic reactor is 0-3:0-2:0.1-0.

8. During the single aluminum deposition stage, adjust the H2 flux in the main pipeline to 3-8 SLM; The ratio of Ar gas, H2 gas, and HCl gas flow rates in the low-temperature reaction zone is 0-2 : 2-5 : 0.2-1.0; The ratio of Ar gas, H2 gas, and HCl gas flux in the mesophilic reactor is 0-2:0-3:

0.

10. The method for preparing a diffusion-type aluminide coating by multi-element chemical vapor co-deposition according to claim 9, characterized in that, Deposition time includes the co-deposition time of active elements and the deposition time of single aluminum; The ratio of co-deposition time to deposition time of active elements is 0.02-0.2:1, in order to achieve effective doping of active elements and avoid their excessive aggregation.

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