A forming process for a chemical vapor deposition furnace tank

Abstract

This invention relates to a forming process for a chemical vapor deposition furnace tank. The tank has several reinforcing rings both inside and outside, with adjacent reinforcing rings connected by longitudinal ribs. The reinforcing rings inside the tank are all rigid, while the reinforcing rings outside the tank are all ductile. First, rolled alloy plates are selected as the tank body material. High-carbon steel rings are selected as the internal reinforcing rings, and low-carbon steel rings are selected as the external reinforcing rings. Then, the rolled alloy plates are cut according to the furnace tank dimensions and bent to form the tank body. Next, the bent plates are welded and assembled into the furnace tank body, and internal and external reinforcing rings are welded onto the tank body. Finally, a Y-modified aluminum compound coating is prepared on the inner surface of the tank using a vapor deposition process, resulting in the chemical vapor deposition furnace tank. This invention has a simple manufacturing process, good stability, and can comprehensively solve the problems of dimensional and structural stability of furnace tanks under high temperature and large temperature gradient conditions, improving their reliability and service life.

Description

Technical Field

[0001] This invention belongs to the field of vapor deposition reaction and relates to a vapor deposition reaction equipment preparation technology, specifically to a forming process for a chemical vapor deposition furnace. Background Technology

[0002] The furnace canister is a core component of CVD (Chemical Vapor Deposition) equipment for hollow blades, and also a crucial part for internal surface coating processing. Because the furnace canister operates in a high-temperature, corrosive atmosphere for extended periods, its strength gradually decreases, leading to reduced structural stability, operational safety, and reliability, ultimately shortening its service life. Current furnace canister manufacturing technologies primarily employ external reinforcing ribs to extend service life, but these methods still fail to adequately meet long-term performance requirements.

[0003] 1. During use, the temperature of the furnace can reach over 1000 degrees Celsius. Under long-term high temperature, the strength of the furnace material will decrease to a certain extent, reducing its service life.

[0004] 2. When the furnace is in use, the reaction inside it produces corrosive gases, especially chloride ions, which have a strong corrosive effect on the tank material at high temperatures, damaging the tank structure and reducing the stability of the tank.

[0005] 3. During the reaction coating process, the furnace tank is under negative pressure for a long time. Under the long-term effects of high temperature, its own weight, and the pressure difference between the inside and outside, the furnace tank will undergo creep deformation, which will lead to a decrease in its reliability and structural stability.

[0006] 4. Under long-term high-temperature environment, the surface of the furnace can is in contact with air, which makes it very easy for surface oxidation to occur, thereby further reducing the service life of the furnace can.

[0007] 5. Under the combined effects of high temperature, chloride ion corrosion, and negative pressure, the furnace can collapse, thus greatly reducing its service life.

[0008] Therefore, there is an urgent need for a technology to further improve the durability and stability of chemical vapor deposition furnaces. Summary of the Invention

[0009] The purpose of this invention is to provide a chemical vapor deposition furnace tank forming process, which significantly improves the service life of the furnace tank by designing the furnace tank structure and forming process.

[0010] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0011] On one hand, the present invention provides a chemical vapor deposition furnace tank, including a tank body, wherein a plurality of reinforcing rings are respectively provided inside and outside the tank body, and adjacent reinforcing rings are connected by longitudinal ribs; the reinforcing rings inside the tank body are all rigid reinforcing rings, and the reinforcing rings outside the tank body are all flexible reinforcing rings.

[0012] This invention provides rigid and tough reinforcing rings inside and outside the tank, respectively. The rigid reinforcing rings have better corrosion resistance and compressive strength than the tough reinforcing rings. By combining the inner and outer reinforcements, the drawbacks of each are avoided and the advantages of each are utilized. The inner rigidity and outer toughness reinforcement design resists creep caused by negative pressure through internal rigidity and improves the stability of the tank under small deformations through external flexibility. As a result, the lifespan of the furnace tank in this application is much greater than that of a single-sided reinforcement.

[0013] Preferably, the rigid reinforcing ring is a high-carbon steel ring coaxially welded to the inner wall of the tank, and the toughening reinforcing ring is a low-carbon steel ring coaxially welded to the outer wall of the tank.

[0014] Preferably, the rigid reinforcing rings on the inner wall of the tank and the tough reinforcing rings on the outer wall are arranged at equal intervals, and the heights of the corresponding rigid reinforcing rings and tough reinforcing rings are corresponding.

[0015] Preferably, the longitudinal rib is a strip steel plate vertically welded to the surface of the tank.

[0016] Preferably, the inner wall of the tank is provided with an anti-corrosion coating that covers the rigid reinforcing ring.

[0017] Preferably, the tank body is composed of an upper conical section, a cylindrical section and a base section welded together, adopting a segmented design, which is convenient for processing and manufacturing; the reinforcing ring is set on the cylindrical section of the tank body.

[0018] Preferably, the base segment is provided with skirts around its perimeter to enhance strength and facilitate connection.

[0019] On the other hand, the present invention provides a forming process for a chemical vapor deposition furnace tank, comprising the following steps:

[0020] Step 1: Material preparation. Rolled alloy plate is selected as the material for tank body preparation. High carbon steel ring is selected as the internal reinforcing ring of the tank, and low carbon steel ring is selected as the external reinforcing ring.

[0021] Step 2: Bending and forming. The rolled alloy plate is cut according to the furnace tank size and bent into shape to obtain the tank body.

[0022] Step 3: Assembly. Weld the bent and shaped plates together to form the furnace tank body. Weld inner and outer reinforcing rings onto the tank body.

[0023] Step 4: Prepare the coating. Use chemical vapor deposition (CVD) to prepare a Y-modified aluminum compound coating on the inner surface of the tank to obtain a chemical vapor deposition tank. The mass percentage of Y in the Y-modified aluminum compound coating is 10%~30%.

[0024] Preferably, the rolling process of the alloy plate uses a roughing double-shaft mill with a reduction of 10~25mm per pass, an initial rolling temperature of 1000-1050℃, and a final rolling temperature of 810-850℃.

[0025] Preferably, the rolled alloy plate is a nickel-based high-temperature alloy, including grades such as M247, K444, K452, and In718.

[0026] Preferably, the upper conical section, cylindrical section and base section of the tank are rolled or bent into shape and then welded together.

[0027] Preferredly, during assembly, ERNiCrMo-1 material is selected as the filler material for welding between plates. Its main elements are Fe, Mn, Co, Cr, Mo and Ni, and its strength is higher than that of the selected nickel-based superalloy plate.

[0028] Prioritize welding with a voltage and current of 100-150A and 10-15V during assembly. Use argon as a protective gas during welding and weld at a speed of 100-135mm / min to ensure uniform welding. Use a 6-layer welding process to connect the tank structure.

[0029] The present invention also provides a process for preparing the coating in the forming process of the chemical vapor deposition furnace tank as follows:

[0030] Step 4.1: Prepare the infiltration agent, which includes AlY, AlFe, and NH4Cl. By adjusting the distribution ratio of each component of the infiltration agent, the molar ratio of Al to Y is 6-8:2-4, and the mass percentage of NH4Cl in the infiltration agent is 1%-2%. Spread the infiltration agent at the bottom of the vapor deposition chamber.

[0031] Step 4.2: Place the welded furnace tank body above the seepage agent in the vapor deposition chamber;

[0032] Step 4.3: Deposition. Heat the vapor deposition chamber to the deposition temperature and introduce process gas to perform Al and Y co-deposition. During the deposition process, control the pressure in the vapor deposition chamber to cyclically change within the range of 4-60 kPa. After the required deposition thickness is reached, stop introducing process gas and end the deposition. Prepare a Y-modified aluminum oxide coating on the inner surface of the furnace tank.

[0033] Preferably, the thickness of the Y-modified aluminide coating is 10-30 μm.

[0034] Preferably, the distance between the furnace tank body and the spreading infiltrate is 90-110 mm.

[0035] Preferably, the deposition temperature is 900-1100℃ and the deposition time is 1.5-3 h.

[0036] Preferably, after deposition is completed, the process gas is shut off, and an inert gas is introduced to clean the deposition chamber for a period of time. After the deposition chamber cools down to room temperature, the furnace tank is removed to obtain the Y-modified aluminum compound coating deposited on the surface of the furnace tank.

[0037] Preferably, the process gas includes H2 and HCl.

[0038] Preferably, before heating the vapor deposition chamber, process gas is introduced for purging, and the pressure inside the vapor deposition chamber is checked to ensure it meets the test requirements.

[0039] Preferably, after placing the furnace tank body into the vapor deposition chamber, a vacuum pump is used to evacuate the chamber, and the airtightness of the vapor deposition chamber is tested.

[0040] Preferably, during co-deposition, the pressure change in the vapor deposition chamber is controlled by a pulse, and the pulse waveform is a triangular pulse wave or a trapezoidal pulse wave.

[0041] The following benefits can be obtained by using this invention:

[0042] 1. In this invention, the furnace tank is prepared by adding heterogeneous reinforcing ribs (rigid reinforcing rings and tough reinforcing rings) both inside and outside. This can effectively improve the stability and strength of the furnace tank under the long-term action of high temperature, self-weight and internal and external pressure difference, and effectively slow down the occurrence of crushing.

[0043] 2. In this invention, the furnace tank is made of nickel-based high-temperature alloy as the base material, and a high-temperature corrosion-resistant coating is prepared on the surface to further improve the corrosion resistance of the furnace tank, slow down the high-temperature corrosion of the furnace tank caused by corrosive atmospheres such as chloride ions during use, and improve the reliability and structural stability of the furnace tank.

[0044] 3. The furnace tank in this invention is manufactured using ERNiCrMo-1 material welding, which has higher strength than alloy plates, ensuring that the furnace tank will not crack due to strength issues during application, thereby improving the reliability and service life of the furnace tank.

[0045] 4. This invention prepares a Y-modified aluminide coating as a high-temperature corrosion-resistant coating. By adding element Y, the interdiffusion of Ni and Al is significantly promoted, which can significantly increase the Al content in the matrix. At the same time, the addition of rare earth Y reduces the hardness of the coating, thereby improving the room temperature brittleness of the coating. Furthermore, rare earth Y is mainly distributed in the diffusion layer of the coating (the bonding layer between the Y-modified aluminide coating and the matrix). During oxidation, the rare earth elements in the diffusion layer can form oxide particles, pinning grain boundaries and phase boundaries, improving the adhesion between the coating and the matrix, which further reduces the tendency of the oxide film to crack and peel off.

[0046] The Y-modified aluminide coating exhibits significantly lower corrosion weight gain during high-temperature chloride ion corrosion tests under the same conditions compared to the alloy. It also shows a smoother corrosion kinetic curve and a flatter, denser corrosion layer, demonstrating superior corrosion resistance. In summary, this represents a complete forming process for the furnace tank, including the design of the furnace tank structure, the forming of the tank body, the welding of the joints, and the preparation of the coating. Attached Figure Description

[0047] Figure 1 This is a flow chart of the chemical vapor deposition furnace tank forming process of the present invention.

[0048] Figure 2 This is a schematic diagram of the external structure of the chemical vapor deposition furnace tank of the present invention.

[0049] Figure 3 This is a cross-sectional view of the chemical vapor deposition furnace of the present invention.

[0050] Figure 4 This is a top view of the chemical vapor deposition furnace tank of the present invention after the upper conical section has been removed.

[0051] Figure 5 Metallographic microscope images of the Y-modified aluminide coating prepared for the example;

[0052] Figure 6 Scanning electron microscope images of the Y-modified aluminide coating prepared for the example;

[0053] Figure 7 The energy spectrum of Y-modified aluminide coating prepared in the example is shown.

[0054] In the diagram: 1-Upper conical section, 2-Cylindrical section, 3-Base section, 4-Tough reinforcing ring, 5-Tough rectangular steel plate, 6-Rigid rectangular steel plate, 7-Rigid reinforcing ring, 8-Skirt. Detailed Implementation

[0055] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0056] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0057] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0058] like Figures 2 to 3 As shown, the present invention provides a chemical vapor deposition furnace tank, including a tank body, wherein a plurality of reinforcing rings are respectively provided inside and outside the tank body, and adjacent reinforcing rings are connected by longitudinal ribs; the reinforcing rings inside the tank body are all rigid reinforcing rings 7, and the reinforcing rings outside the tank body are all flexible reinforcing rings 4.

[0059] It should be noted that the number of rigid reinforcing rings 7 is not limited to a minimum of two, but generally should be 2-10, with the specific number depending on the tank size. Figure 3 Three examples are given, and the number of toughening stiffening rings 4 is the same. (See attached image.) Figure 3 Three examples are given in the text.

[0060] Generally speaking, the rigid stiffening ring 7 has better corrosion resistance than the tough stiffening ring 4. By combining internal and external reinforcement, the shortcomings of each can be avoided. At the same time, the internal rigid and external tough reinforcement design can resist creep caused by negative pressure through internal rigidity and improve the stability of the tank under small deformation through external flexibility, so that the life of the furnace tank in this application is much greater than that of single-sided reinforcement.

[0061] The tank can be any tank in the prior art, for example, such as Figure 2 and Figure 3 As shown, the tank body is composed of an upper conical section 1, a cylindrical section 2, and a base section 3 welded together. The reinforcing ring is set on the cylindrical section 2 of the tank body. The three-section tank body not only improves the strength of the tank body itself and adapts to the shape required for the reaction, but also facilitates the installation and preparation of the reinforcing ring.

[0062] It should be noted that the rigid reinforcing ring 7 can be any annular rigid steel plate fixed to the inner wall of the tank in the prior art. For example, it can be a high-carbon steel ring coaxially welded to the inner wall of the tank.

[0063] It should be noted that the toughening reinforcing ring 4 can be any annular tough steel plate fixed to the inner wall of the tank in the prior art. For example, it can be a low-carbon steel ring coaxially welded to the outer wall of the tank.

[0064] It should be noted that if Figure 2 and Figure 3 As shown, the rigid reinforcing ring 7 on the inner wall of the tank and the tough reinforcing ring 4 on the outer wall are arranged at equal intervals, and the heights of the rigid reinforcing ring 7 and the tough reinforcing ring 4 are corresponding. The equal interval arrangement improves the reinforcement performance of the tank, and the corresponding height arrangement of the inner and outer walls allows the rigid reinforcing ring 7 and the tough reinforcing ring 4 to act on the same stress area of ​​the tank simultaneously, thereby improving performance through coordination.

[0065] It should be noted that if Figure 3 and Figure 4 As shown, the longitudinal ribs are strip steel plates (or rectangular steel plates) welded vertically to the surface of the tank. The strip steel plates (or rectangular steel plates) can further improve the stability and lifespan of the tank. Here, verticality includes two layers. The first layer is that the strip steel plate itself is set vertically, that is, the length direction is the same as the axial direction of the tank. The second layer is that the strip steel plate is perpendicular to the surface of the tank.

[0066] As an improved embodiment, the longitudinal ribs used to connect the rigid stiffening rings 7 are rigid rectangular steel plates 6. The rigid rectangular steel plates 6 are not only welded to the side walls of two adjacent rigid stiffening rings 7 at their ends, but also welded to the inner wall of the tank.

[0067] The longitudinal ribs used to connect the toughening stiffening rings 4 are tough rectangular steel plates 5. The tough rectangular steel plates 5 are not only welded to the side walls of two adjacent toughening stiffening rings 4 at the ends, but also welded to the outer wall of the tank.

[0068] It should be noted that each pair of adjacent stiffening rings is connected by multiple longitudinal ribs, for example, in one embodiment, such as... Figure 4 As shown, four tough rectangular steel plates 5 are set between two adjacent toughness reinforcing rings 4. For tanks with more than two reinforcing rings on the inner or outer side, such as three reinforcing rings, the longitudinal ribs in the upper and lower directions correspond one-to-one, that is, they are on the same axial line.

[0069] It should be noted that the tank itself is made of high-temperature resistant alloys, such as nickel-based high-temperature alloys or cobalt-based high-temperature alloys.

[0070] As an improved embodiment, the base section 3 is provided with skirts 8 around its perimeter to enhance strength and facilitate connection. The skirts 8 not only increase the emphasis of the cylindrical section 2, but also allow for the provision of bolt holes to facilitate the fixation of the entire chemical vapor deposition furnace.

[0071] This invention also provides a forming process for a chemical vapor deposition furnace tank, comprising the following steps:

[0072] Step 1: Material preparation. Rolled alloy plate (nickel-based high-temperature alloy plate) is selected as the material for tank body preparation. High-carbon steel rings are selected as internal reinforcing rings for the tank body, and low-carbon steel rings are selected as external reinforcing rings. The rolling process of the rolled alloy plate adopts a rough rolling double new shaft, with a reduction of 10~25mm per pass, an initial rolling temperature of 1000-1050℃, and a final rolling temperature of 810-850℃.

[0073] Step 2: Bending and forming. Cut the rolled alloy plate according to the furnace size and use hot bending process to bend and form the alloy plate.

[0074] Step 3: Assembly. The bent plates are welded and assembled into the furnace tank body. Inner and outer reinforcing rings are welded onto the tank body. Welding is used at the joints between the plates. ERNiCrMo-1 material is selected as the filler material for the welding process. Its main elements are Fe, Mn, Co, Cr, Mo, and Ni. Its strength is higher than that of the selected nickel-based high-temperature alloy plate. Welding is performed at a voltage and current of 100-150A and 10-15V. Argon gas is used as the protective gas during the welding process, and the welding speed is 100-135mm / min to ensure uniform welding. A 6-layer welding process is used to connect the tank structure.

[0075] Step 4: Prepare the coating. Use chemical vapor deposition (CVD) to prepare a Y-modified aluminum compound coating on the inner surface of the tank to obtain a chemical vapor deposition tank. The mass percentage of Y in the Y-modified aluminum compound coating is 10%~30%.

[0076] The preparation method of Y-modified aluminide coating is as follows:

[0077] 1) Preparation of the infiltration agent: Take AlY powder and AlFe powder according to the elemental molar ratio Al:Y=6:4, and take NH4Cl powder according to the total mass ratio of 1% and mix them thoroughly;

[0078] 2) Setting out: Break the vacuum in the deposition chamber, select different proportions of infiltrator prepared in step 1) according to the requirements and place them evenly in the deposition chamber. Fix the furnace tank body on the fixture, align the bottom opening of the furnace tank body with the gas distribution plate, so that the process gas passes through the gas distribution plate and directly enters the inner wall of the tank to deposit on the inner wall of the tank. Adjust the distance between the furnace tank body and the infiltrator.

[0079] 3) Evacuate and adjust the pressure: Evacuate the sedimentation chamber, check the airtightness of the device, and when the pressure change is less than 10 Pa / min, purge H2 and Ar to adjust the pressure of the sedimentation chamber to 40 kPa.

[0080] 3) Deposition: Turn on the cooling water circulation, set the deposition temperature to 900℃ and the time to 1.5h. When the deposition chamber temperature reaches the deposition temperature, HCl and H2 are introduced at the set flow rate. The pressure circulation range is set to 4-50 kPa. The gas valve connecting the deposition chamber and the water ring pump is controlled to achieve periodic changes in the pressure of the deposition chamber. When the deposition time is reached, the deposition ends.

[0081] 4) Sampling: Turn off HCl and H2, purge Ar for 10 minutes to clean the deposition chamber, wait for the deposition chamber temperature to cool to room temperature, remove the furnace tank body, and prepare a Y-modified aluminum compound coating on the inner surface of the furnace tank body.

[0082] The prepared Y-modified aluminide coating was observed using a metallographic microscope, such as... Figure 5 As shown, the coating is uniform and dense, with a thickness of approximately 11.2 μm; Figure 6 A 2000x magnification image of the coating, taken using a scanning electron microscope, revealed good adhesion between the coating and the substrate. Electron probe microanalysis was used to observe the distribution of Y element within the coating, and the results are as follows... Figure 7 As shown, it was found that most of the Y element is concentrated in the interdiffusion layer, which has a significant impact on the coating performance.

[0083] The above embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Although the invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the invention do not depart from the spirit and scope of the invention and should be covered within the scope of the claims of the invention.

Claims

1. A forming process for a chemical vapor deposition furnace tank, characterized in that, Includes the following steps: Material preparation: Rolled alloy plate was selected as the material for tank body preparation, high carbon steel rings were selected as internal reinforcing rings for the tank, and low carbon steel rings were selected as external reinforcing rings. Bending and forming involves cutting the rolled alloy sheet according to the furnace tank size and bending the sheet to form the tank body. Assembly involves welding the bent and shaped plates together to form the furnace tank body, and welding inner and outer reinforcing rings onto the tank body. A coating was prepared by using chemical vapor deposition (CVD) to prepare a Y-modified aluminum compound coating on the inner surface of the tank, resulting in a chemical vapor deposition tank. The mass percentage of Y in the Y-modified aluminum compound coating was 10% to 30%.

2. The forming process of the chemical vapor deposition furnace tank according to claim 1, characterized in that: Adjacent reinforcing rings are connected by longitudinal ribs, which are strip steel plates vertically welded to the surface of the tank.

3. The forming process of the chemical vapor deposition furnace tank according to claim 1, characterized in that: The tank body is composed of an upper conical section, a cylindrical section and a base section welded together, and the reinforcing ring is provided on the cylindrical section of the tank body.

4. The forming process of the chemical vapor deposition furnace tank according to claim 3, characterized in that: The base section is surrounded by skirts to enhance strength and facilitate connection.

5. The forming process of the chemical vapor deposition furnace tank according to claim 1, characterized in that: During assembly, ERNiCrMo-1 material is selected as the filler material for welding between the plates, and argon is used as the protective gas during the welding process.

6. The forming process of the chemical vapor deposition furnace tank according to any one of claims 1-5, characterized in that: The process for preparing the coating is as follows: Prepare a permeation agent comprising AlY, AlFe, and NH4Cl. Adjust the distribution ratio of each component of the permeation agent to make the molar ratio of Al to Y 6-8:2-4, and the mass percentage of NH4Cl in the permeation agent 1%-2%. Spread the permeation agent at the bottom of the vapor deposition chamber. Place the welded furnace tank body above the seepage agent in the vapor deposition chamber; Deposition involves heating the vapor deposition chamber to the deposition temperature and introducing process gas for Al and Y co-deposition. During the deposition process, the pressure inside the vapor deposition chamber is controlled to cyclically change within the range of 4-60 kPa. Once the desired deposition thickness is reached, the process gas is stopped, and the deposition process is completed, resulting in a Y-modified aluminum oxide coating deposited on the surface of a nickel-based superalloy sample.

7. The forming process of the chemical vapor deposition furnace tank according to claim 6, characterized in that: The thickness of the Y-modified aluminide coating is 10-30 μm.

8. The forming process of the chemical vapor deposition furnace tank according to claim 6, characterized in that: The distance between the nickel-based superalloy sample and the spreading infiltration agent is 90-110 mm.

9. The forming process of the chemical vapor deposition furnace tank according to claim 2, characterized in that: The deposition temperature is 900-1100℃, and the deposition time is 1.5-3 h.

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