Tool for preparing blade coating through CVD (Chemical Vapor Deposition)

Abstract

The utility model discloses a tool for preparing a blade coating through CVD (Chemical Vapor Deposition), and belongs to the technical field of chemical vapor deposition. The tool comprises three layers of base plates which are arranged in parallel from top to bottom, and blades on which coatings are to be deposited are placed on the base plates; the three layers of substrates are supported and connected through supporting rods; wherein three coaxial round holes are formed in the center positions of the three layers of base plates, and air inlet hole rods are arranged in the three round holes in a penetrating mode; the air inlet hole rod is of a hollow rod structure, and a plurality of air outlet holes are evenly formed in the side wall of the hollow rod. The top end of the air inlet hole rod is sealed, and the bottom end of the air inlet hole rod communicates with the air inlet cloud disc. The tool is arranged in the reaction kettle, and can effectively buffer gas, so that the gas is fully mixed, and the gas diffusion is facilitated; and a larger effective airflow circulation area can be created, and deep holes and thin holes of the blade can be uniformly plated.

Description

Technical Field

[0001] This utility model relates to the field of chemical vapor deposition technology, specifically to a tooling for CVD preparation of blade coatings. Background Technology

[0002] Chemical vapor deposition (CVD) technology was used to prepare aluminide coatings on the surface of aero-engine blades. The preparation process includes the generation of gaseous aluminides and aluminizing. The reactive gas first reacts with the aluminum-donating agent in a diffusion agent generator to generate gaseous halides. Then, using a gas carrier (H2), the gaseous halides are transported through an insulated pipe to a high-temperature reaction chamber, where they react with the blade substrate under high-temperature, low-pressure conditions to form the aluminide coating.

[0003] In chemical vapor deposition (CVD), uniform distribution of gaseous raw materials can accelerate the deposition rate and improve the density and uniformity of the deposited coating. However, when using existing CVD equipment to deposit aluminide coatings on blade surfaces, the reactor has only one gas inlet with a low height, which cannot quickly diffuse to every part of the effective isothermal zone. Sometimes, uneven gas diffusion occurs, and even the edges may not be reached, leading to unstable reaction rates between the halide gas and the substrate, uneven blade coating, or even no coating deposited on the workpiece surface at the edges. Insufficient inlet height and small convection space may also cause uneven coating thickness inside the blade cavity and coating failure inside deep holes.

[0004] Therefore, improving the quality and deposition efficiency of CVD coatings on blade surfaces is a pressing technical problem that needs to be solved. Utility Model Content

[0005] The purpose of this invention is to provide a tooling for CVD preparation of blade coatings. This tooling is installed inside the reactor and can effectively buffer the gas, make the gas fully mixed, and help the gas diffusion; it can also create a larger effective airflow circulation zone, so that the deep holes and fine holes of the blades can be uniformly coated.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A CVD tooling for preparing blade coatings includes three parallel substrates arranged from top to bottom, on which blades to be coated are placed; the three substrates are supported and connected by support rods; wherein: three coaxial circular holes are opened at the center of the three substrates, and air inlet rods are inserted through the three circular holes; the top end of the air inlet rods is sealed, and the bottom end of the air inlet rods is connected to an air inlet disk.

[0008] Furthermore, the substrate has fixing holes, and the support rods are inserted into the fixing holes on the substrate and fastened with bolts; there are 4 support rods, and there are also 4 fixing holes on each substrate; the diameter of the support rods is 12-20mm.

[0009] Furthermore, the air inlet rod is a hollow rod structure, with several air outlet holes evenly opened on the side wall of the hollow rod. The outer diameter of the hollow rod is 40-50mm, the wall thickness of the hollow rod is 2-4mm, and the diameter of the air outlet holes is 2-4mm.

[0010] Furthermore, each substrate layer has a thermocouple hole, and the measuring end of the thermocouple is placed in the thermocouple hole; the diameter of the thermocouple hole is 30-35mm.

[0011] Furthermore, the air intake cloud disk includes an outer shell and multiple gas flow channels within the outer shell. An air intake port is located at the bottom of the outer shell, through which the carrier gas and precursor gas used in CVD deposition are introduced. After passing through the multiple gas flow channels, they enter the air intake port rod. The outer shell of the air intake cloud disk is a cuboid, and multiple gas flow channels arranged vertically and parallel to each other are located within the outer shell, with the connecting openings between adjacent layers on opposite sides.

[0012] Furthermore, the substrate is provided with a plurality of slits, including long slits and short slits, and the long slits and short slits are arranged radially and alternately around the central circular hole of the substrate.

[0013] Furthermore, the air intake vent rod, support rod, and air intake cloud disk are made of 310S stainless steel.

[0014] The advantages and beneficial effects of this utility model are as follows:

[0015] 1. When the tooling of this utility model introduces gas, the reaction gas is first fully mixed in the air inlet cloud disk and undergoes a secondary effective reaction. Then, it is evenly sprayed out through the air inlet hole rod and diffused to every part of the effective uniform temperature zone, so that every workpiece (blade) on the substrate can be evenly contacted with the gaseous halide generated by the reaction of the reaction gas and the penetrant, and carry out effective reaction deposition. The substrate reaction rate is more stable and the coating thickness is more uniform.

[0016] 2. When using the tooling of this utility model to deposit aluminide coating on the blade surface, the carrier gas, precursor gas and unreacted reaction gas first enter the inlet cloud disk, where they can be fully mixed and undergo a secondary effective reaction in the multi-layer gas flow channel of the inlet cloud disk, and then uniformly sprayed out through the holes on the inlet air hole rod, which can form a uniform coating on the workpiece.

[0017] 3. When using the tooling of this utility model to deposit aluminide coating on the blade surface, the design of multiple slits on the substrate allows excess gas after deposition to be quickly extracted and discharged by a vacuum pump, providing a larger convection space and forming an effective airflow circulation. This allows for uniform coating of complex-shaped surfaces and deep and fine holes in the blade.

[0018] 4. In this utility model tooling, a three-layer substrate is used, which allows a large number of substrates to be placed in the same furnace. Attached Figure Description

[0019] Figure 1 This is a three-dimensional view of the coating tooling structure of this utility model.

[0020] Figure 2 This is a front view of the coating tooling of this utility model;

[0021] Figure 3 This is a schematic diagram of the coil in the tooling of this utility model;

[0022] Figure 4 This is a schematic diagram of the base plate in the tooling of this utility model;

[0023] In the diagram: 1-Inlet vent rod; 101-Outlet vent; 2-Thermocouple hole; 3-Substrate; 301-Long slit; 302-Short slit; 4-Support rod; 5-Inlet cloud disk; 501-Outer shell; 502-Cloud disk inlet vent; 503-Multi-layer gas flow channel. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings.

[0025] This invention provides a tooling for CVD preparation of blade coatings, such as... Figure 1-4 As shown. The fixture includes three substrates 3 arranged in parallel from top to bottom. The substrates 3 are used to place the workpieces (blades) to be coated. By using three substrates, a large number of workpieces can be placed in the same furnace.

[0026] The three-layer substrate is supported and connected by support rods 4. Specifically, each substrate 3 has four fixing holes, and the support rods 4 are inserted into the fixing holes and fastened with bolts. The diameter of the support rods is preferably 15mm.

[0027] The tooling also includes an air inlet rod 1, which is a hollow rod structure with a closed top and an open bottom. Several air outlet holes 101 are evenly opened on the side wall of the hollow rod. The outer diameter of the hollow rod is preferably 45 mm, the wall thickness is preferably 3 mm, and the diameter of the air outlet holes 101 on the side wall is preferably 3 mm.

[0028] The air intake rod 1 is inserted into a circular hole at the center of the three-layer substrate (the side wall of the air intake rod is in contact with the edge of the central circular hole of the substrate), and the bottom end of the air intake rod 1 is connected to the coil 504 in the air intake disk 5.

[0029] The air intake cloud disk 5 includes an outer shell 501 and a multi-layer gas flow channel 503 inside the outer shell. The bottom of the outer shell is provided with a cloud disk air intake hole 502. The carrier gas and precursor gas during CVD deposition are introduced through the cloud disk air intake hole 502, and after passing through the multi-layer gas flow channel 503, they enter the air intake hole rod 1.

[0030] Preferably, the outer shell 501 of the air intake disk is a cuboid shell, and the shell contains multiple layers of gas flow channels 503 arranged in parallel vertically, with the connecting openings of adjacent layers on opposite sides. The lower end of the air intake vent rod 1 passes through the outer shell of the air intake disk and extends into the uppermost layer of the multiple gas flow channels. That is, after the mixed gas flows to the uppermost layer of the multiple gas flow channels, it directly enters the air intake vent rod 1.

[0031] Preferably, the substrate 3 has multiple slits, including long slits 301 and short slits 302, which are arranged radially and alternately around the central circular hole of the substrate. This slit design facilitates further diffusion and exhaust of gas.

[0032] Preferably, each substrate of the tooling of this utility model has a thermocouple hole 2, and the measuring end of the thermocouple is placed in the thermocouple hole 2; the diameter of the thermocouple hole is preferably 32mm.

[0033] Preferably, the air intake rod 1, the support rod 4, and the air intake disk 5 are made of 310S stainless steel.

[0034] When using this tooling, the working end of the thermocouple inside the reactor is placed in the thermocouple hole of the tooling, and the air inlet of the air inlet disk is connected to the air inlet of the reactor. The workpiece (blade) is evenly and reasonably placed on the three-layer substrate, and then the reactor and heating furnace are covered. The exhaust end of the reactor is connected to a vacuum pump. During the reaction process, the periodic change of pressure in the reaction chamber is controlled by adjusting the proportional regulating valve connected to the vacuum pump, thereby achieving uniform deposition of the coating in the deep and fine pores of the blade.

[0035] Example 1:

[0036] This embodiment describes the preparation of an aluminized coating on a single-crystal superalloy blade using chemical vapor deposition (CVD). During the CVD process, the reactive gas HCl and an Al-containing diffusion agent react in a diffusion agent generator to produce a gaseous halide, AlCl₂. xThe precursor, a gaseous halide precursor, and a very small amount of unreacted reactive gas (HCl) are introduced into the inlet cloud disk through an insulated pipe along with the carrier gas H2. After thorough mixing and a secondary effective reaction, the mixture enters the inlet vent rod and is uniformly sprayed out through the exhaust port, diffusing outwards. The gaseous halide diffuses to the substrate surface and adsorbs onto it, undergoing a chemical reaction to generate the desired solid film (aluminized coating). The gaseous byproducts generated after the reaction of the reactive gas (HCl) on the substrate surface detach from the substrate surface and are removed by a vacuum pump.

[0037] When gas is introduced into this fixture, it is first thoroughly mixed in the inlet disc for a secondary effective reaction. Then, it is evenly sprayed out through the inlet nozzle, diffusing to every part of the effective uniform temperature zone. This ensures that every workpiece (blade) on the substrate can uniformly contact the gaseous halides generated by the reaction of the reactive gas and the penetrant, resulting in effective reaction deposition. This leads to a more stable substrate reaction rate and a more uniform coating thickness. Excess gas is extracted and discharged, creating a larger convection space and forming an effective airflow circulation, enabling uniform coating even on complex surfaces and in deep or fine holes in blades.

[0038] This utility model's tooling can be disassembled in sections before use, and its surface can be sandblasted or polished for subsequent use. This utility model not only solves the problem of incomplete and uneven atmosphere coverage within the reactor, but also controls deposition efficiency and process stability, making it easier to uniformly coat the surfaces of complex-shaped workpieces, as well as their deep and fine holes, directly improving production efficiency. It eliminates the need to design special air intake tooling for each type of blade, saving production costs.

[0039] This utility model includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the overall innovative concept of this utility model shall be considered within the protection scope of this utility model.

Claims

1. A tooling for CVD preparation of blade coatings, characterized in that: The fixture includes three parallel substrates arranged from top to bottom, on which blades to be coated are placed. The three substrates are supported and connected by support rods. Among them, three coaxial circular holes are opened at the center of the three substrates, and air inlet rods are inserted through the three circular holes. The air inlet rods are hollow rods with several air outlet holes evenly opened on the side walls of the hollow rods. The top of the air inlet rods is sealed, and the bottom of the air inlet rods is connected to the air inlet disk.

2. The tooling for CVD preparation of blade coatings according to claim 1, characterized in that: The substrate has fixing holes, and the support rods are inserted into the fixing holes on the substrate and fastened with bolts; there are 4 support rods, and there are also 4 fixing holes on each substrate; the diameter of the support rods is 12-20mm.

3. The tooling for CVD preparation of blade coatings according to claim 1, characterized in that: The hollow rod has an outer diameter of 40-50mm, a wall thickness of 2-4mm, and an air outlet diameter of 2-4mm.

4. The tooling for CVD preparation of blade coatings according to claim 1, characterized in that: Each substrate layer has a thermocouple hole, and the measuring end of the thermocouple is placed in the thermocouple hole; the diameter of the thermocouple hole is 30-35mm.

5. The tooling for CVD preparation of blade coatings according to claim 1, characterized in that: The air intake cloud disk includes an outer shell and multiple gas flow channels inside the outer shell. The bottom of the outer shell is provided with a cloud disk air intake hole. The carrier gas and precursor gas during CVD deposition are introduced through the cloud disk air intake hole and enter the air intake hole rod after passing through the multiple gas flow channels.

6. The tooling for CVD preparation of blade coatings according to claim 5, characterized in that: The outer shell of the air intake cloud disk is a cuboid shell, and the shell contains multiple layers of gas flow channels arranged in parallel vertically, with the connection ports of adjacent layers on opposite sides.

7. The tooling for CVD preparation of blade coatings according to claim 1, characterized in that: The substrate has multiple slits, including long slits and short slits, which are arranged radially and alternately around the central circular hole of the substrate.

8. The tooling for CVD preparation of blade coatings according to claim 1, characterized in that: The air intake vent rod, support rod, and air intake cloud disk are made of 310S stainless steel.

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