A process for co-deposition of turbine blade shroud and airfoil coatings

Abstract

The application discloses a process method for co-deposition of a turbine blade edge plate and a blade body coating, which comprises the following steps: 1, loading the turbine blade to be processed into an outer edge plate protection box and an inner edge plate protection box; 2, coating a coating on the turbine blade; vacuumizing the loading chamber and the deposition chamber, when the vacuum degree of the deposition chamber is lower than a threshold value, sending the turbine blade into the deposition chamber through a servo motor, and starting to heat the part. When the thermocouple temperature in the thermocouple tube reaches a process temperature, the heating of the ceramic material ingot is started, until the current reaches a process size, the coating is started to be deposited; in the process of depositing the coating, the turbine blade is subjected to a rotating variable-speed type circular reciprocating motion along the main shaft axis from an initial position 0 to a terminal position 1. According to the design requirement of the coating thickness, the thickness of the coating is controlled by controlling the consumption of the evaporated ceramic material ingot; the turbine blade is retreated to the loading chamber, and after cooling, the turbine blade is taken out, so that the heat-resistant temperature and the working stability of the turbine blade are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine turbine blade manufacturing, specifically to a process method for co-deposition of turbine blade edge plate and blade body coating. Background Technology

[0002] Currently, the use of electron beam physical vapor deposition (EB-PVD) technology to prepare thermal barrier coatings for aero-engine turbine blades has advantages such as high bonding strength between the coating and the substrate, the ability to obtain columnar crystal structure, easy and precise control of the coating chemical composition, and long coating life. Therefore, this technology has been widely used in the preparation and processing of high-temperature protective coatings for turbine blades of various types of aero-engines, which has significantly improved the turbine blades' resistance to high-temperature oxidation, corrosion and heat insulation performance, and extended the engine's service life.

[0003] In the EB-PVD technology, the blade is placed above the ingot during coating deposition. An electron beam gun heats the part, while another electron beam gun evaporates the ingot, causing the coating vapor to be deposited onto the blade surface, forming a typical columnar crystalline structure.

[0004] However, in the existing technology, the thermal barrier coatings grown on the surface of turbine blade rim plates at a certain angle to the steam direction have a relatively small angle, resulting in a loose ceramic coating structure and weak bonding strength (<5MPa). This makes them very easy to peel off, which means that the thermal barrier coating cannot effectively protect the rim plate area. As a result, it is difficult to meet the design technical requirements for high-temperature thermal protection of the turbine blade rim plate area of ​​aero-engines. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a process for co-deposition of coatings on turbine blade rim plates and blade body, which solves the problems in the prior art and ensures that the entire flow channel surface of the turbine blade is covered by a thermal barrier coating, thereby significantly improving the heat resistance temperature and operational stability of the turbine blade.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A process for co-depositing a coating on a turbine blade rim and blade body includes the following steps:

[0008] Step 1: Install the turbine blades to be processed into the outer edge plate protection box and the inner edge plate protection box;

[0009] Step 2: Apply a coating to the turbine blades;

[0010] The specific process of applying the coating includes:

[0011] The loading chamber and deposition chamber are evacuated. When the vacuum level in the deposition chamber is lower than the threshold, the turbine blades are sent into the deposition chamber by a servo motor to start heating the parts. When the temperature of the thermocouple in the thermocouple tube reaches the process temperature, the ceramic ingot is heated until the current reaches the process value, and then the coating is deposited.

[0012] During the coating deposition process, the turbine blades undergo a variable-speed cyclic reciprocating motion along the main shaft axis from the initial position "0" to the final position "1". The coating thickness is controlled by adjusting the consumption of the evaporated ceramic ingots according to the coating thickness design requirements.

[0013] The turbine blades are moved into the loading chamber and, after cooling, are removed. The turbine blades have a thermal barrier coating on the entire flow path and the uncoated areas are protected.

[0014] Preferably, the turbine blades are cleaned before clamping, and acetone is used as the cleaning agent.

[0015] Preferably, the protective clamp consists of an outer edge plate protective box and an inner edge plate protective box, which are connected by a high-temperature alloy wire; the outer edge plate protective box is connected to the tooling connecting rod by welding, and the tooling connecting rod is connected to the rotating spindle of the equipment by connecting screws.

[0016] Preferably, the vacuum threshold is 5×10 -1 Pa.

[0017] Preferably, the spindle rotation speed range is 10-20 rpm during coating deposition.

[0018] Preferably, the distance between the initial position "0" and the ending position "1" is 150mm; the speed steps of the rotational speed change are 0-20mm / min, 20-40mm / min, 40-50mm / min, 20-40mm / min, and 0-20mm / min.

[0019] Preferably, during cooling, when the part is vacuum cooled to below 300°C, air is introduced into the loading chamber, and the furnace door is opened to remove the turbine blades.

[0020] Preferably, the initial position "0" is the ingot vapor cloud formed after the ingot is bombarded and evaporated by the electron beam gun. When the turbine blade, which is clamped in the protective clamp, rotates to the left side of the ingot vapor cloud under the drive of the main shaft of the equipment, this position is the initial position "0" of the spatial position between the turbine blade and the ingot vapor cloud. The steam formed by the ingot vapor cloud forms an angle of more than 20° with the left edge plate of the turbine blade.

[0021] Preferably, the termination position "1" is the position where the ingot vapor is formed after being bombarded and evaporated by the electron beam gun. When the turbine blade, which is clamped in the protective clamp, rotates to the right side of the ingot vapor under the drive of the main shaft of the equipment, this position is the termination position "1" of the spatial position between the turbine blade and the ingot vapor. The steam formed by the ingot vapor forms an angle of more than 20° with the right edge plate of the turbine blade.

[0022] Preferably, the turbine blades, driven by the rotating main shaft, move from the initial position "0" to the final position "1" along the main shaft axis in a non-uniform manner, and then return to the initial position "0" in a non-uniform manner.

[0023] Compared with the prior art, the present invention has the following beneficial technical effects:

[0024] This invention provides a process for co-deposition of thermal barrier coatings on turbine blade rim plates and blade body. By analyzing the structural design characteristics of the entire flow channel surface of the turbine blade and combining the working principle of the EB-PVD equipment, the thermal barrier coatings on the blade body surface and rim plate surface can be co-deposited according to the requirements of the turbine blade coating area by controlling the process parameters. Under the premise of ensuring the bonding strength and columnar crystal structure of the ceramic coating on the blade body surface, the bonding strength of the coating on the rim plate surface is significantly improved (reaching the technical target of ≥30MPa), and a relatively uniform columnar crystal structure is formed. This ensures that the entire flow channel surface of the turbine blade is covered by the thermal barrier coating, and greatly improves the heat resistance temperature and operational stability of the turbine blade rim plate.

[0025] The process method and process parameter control of this invention are simple and easy to process. Furthermore, by adjusting the corresponding process parameters, co-deposition of coatings on the blade rim and blade body of turbine blades of different sizes can be achieved. The product can be widely applied to the preparation of thermal barrier coatings for turbine blades of various types of aero-engines. This method can significantly improve the bonding strength of the coating on the rim surface while ensuring the bonding strength of the coating on the blade body surface, achieving full coverage of the flow channel surface with thermal barrier coating, and greatly improving the service stability of turbine blades. Attached Figure Description

[0026] Figure 1 Schematic diagram of EB-PVD equipment.

[0027] Figure 2 Schematic diagram of steam agglomeration of ingot.

[0028] Figure 3 A schematic diagram showing the initial position of the turbine blades and the spatial position of the steam cluster in the ingot.

[0029] Figure 4 Schematic diagram of the spatial position of the turbine blade termination position and the steam mass of the ingot.

[0030] Figure 5Schematic diagram of the speed at different positions in the variable speed reciprocating motion of the rotary spindle.

[0031] Figure 6 The process method of this invention deposits a coating structure at the rear edge plate.

[0032] Figure 7 The coating structure at the rear edge plate after deposition of the coating using the original process method. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0034] EB-PVD equipment structure as follows Figure 1 As shown, blades 106 are installed in outer edge plate protection boxes 1012 and inner edge plate protection boxes 1013 in loading chamber 102, and the outer edge plate protection boxes 1012 and inner edge plate protection boxes 1013 are connected using high-temperature alloy wire. The outer edge plate protection box 1012 is connected to the tooling connecting rod 107 by welding, and then the tooling connecting rod 107 is connected to the equipment rotating shaft 101 via connecting screw 1014. Driven by the rotating shaft 101, the part extends into the deposition chamber 109 in a rotating manner. An electron beam gun 1011 installed in the gun chamber 103 emits an electron beam 104 to heat the blades 106, and another electron beam gun 108 emits an electron beam 105 for evaporating the ingot 1010. The coating gas generated by the evaporation of the ingot 1010 coats the surface of the rotating blades 106, thereby obtaining a ceramic coating.

[0035] exist Figure 2 In the process, the coating gas generated by the evaporation of the ingot 201 forms a frustum-shaped coating vapor cloud 202. The turbine blade is located in the middle of the vapor cloud 202 to achieve coating. The coating area of ​​the blade is divided into: the blade surface perpendicular to the vapor direction and the rim surface at a certain angle to the vapor direction. The vapor atoms of the ceramic ingot evaporated by the EB-PVD process move upward, which determines that the blade surface perpendicular to the direction of vapor atom movement can form a uniform columnar crystal morphology. The ceramic coating grown on the rim surface at a certain angle to the vapor direction has a relatively loose structure and weak bonding strength (<5MPa) due to the small angle, making it very easy to peel off. As a result, the thermal barrier coating cannot effectively protect the rim area, making it difficult to meet the design technical requirements for high-temperature thermal protection of the rim area of ​​turbine blades in Chinese aero-engines.

[0036] Figure 3This is a schematic diagram showing the initial position of the turbine blade and the spatial position of the ingot vapor cloud in this invention. After the ingot 301 is bombarded and evaporated by an electron beam gun, it forms an ingot vapor cloud 302. In order to achieve coating on the left edge plate (outer edge plate) of the turbine blade 303, the turbine blade 303, which is clamped in the protective clamp 304, rotates at a speed of 10-20 rpm under the drive of the main shaft of the equipment to the left side position of the ingot vapor cloud 302. This position is defined as the initial position "0" of the spatial position between the turbine blade and the ingot vapor cloud. The steam formed by the ingot vapor cloud 302 forms an angle of more than 20° with the left edge plate of the turbine blade 303, thereby significantly improving the coating adhesion of the outer edge plate of the turbine blade 303.

[0037] Figure 4 This is a schematic diagram showing the spatial position of the turbine blade termination position and the steam cloud of the ingot. After the ingot 401 is bombarded and evaporated by an electron beam gun, it forms an ingot steam cloud 402. In order to achieve coating on the right edge plate (inner edge plate) of the turbine blade 403, the turbine blade 403, which is clamped in the protective clamp 404, rotates at a speed of 10-20 rpm under the drive of the main shaft of the equipment to the right side position of the ingot steam cloud 402. This position is defined as the termination position "1" of the spatial position between the turbine blade and the ingot steam cloud. The steam formed by the ingot steam cloud 402 forms an angle of more than 20° with the right edge plate of the turbine blade 403, thereby significantly improving the coating adhesion of the inner edge plate of the turbine blade 403.

[0038] Driven by the rotating main shaft, the turbine blade moves non-uniformly from the initial position "0" along the main shaft axis to the final position "1," and then returns to the initial position "0" again in a non-uniform manner. The distance from the initial position "0" to the final position "1" is 150mm. During this cyclical motion, the deposition distance of the vapor from the ingot to different parts of the blade's flow channel varies. Specifically, at "0," the distance between the vapor on the ingot surface and the outer edge plate is the longest, while at "1," the distance is the longest. The deposition distance is shortest when the blade is in the middle position between "0" and "1." Therefore, due to the difference in deposition distance, variable speed motion is required during the cyclical motion of the blade along the main shaft axis to ensure that the coating thickness of the blade body and edge plates meets design requirements. Calculations and experiments have verified that the speed variation of the turbine blade during the reciprocating motion along the rotating main shaft axis at different positions is as follows: Figure 5 As shown, the initial position "0" is set at 0mm, and the final position "1" is set at 150mm. The blade's cyclical movement through this variable speed mechanism improves the adhesion of the rim coating.

[0039] The specific process for applying a coating to turbine blades using this method is as follows:

[0040] Example 1

[0041] This invention analyzes the structural design characteristics of the entire flow channel surface of guide vanes and, combined with the working principle of EB-PVD equipment, designs a process for vapor deposition coating of the entire flow channel surface of guide vanes. This method can coat the blade surface and the edge plate surface with thermal barrier coating according to the coating area requirements of the guide vanes. While ensuring the bonding strength and columnar crystal structure of the thermal barrier coating on the blade surface, it significantly improves the bonding strength of the coating on the edge plate surface and forms a more uniform columnar crystal structure, thereby ensuring that the entire flow channel surface of the guide vanes is covered by thermal barrier coating, and greatly improving the heat resistance and operational stability of the guide vanes.

[0042] The specific steps are as follows:

[0043] Step 1, Cleaning: Use acetone as a cleaning agent to clean the turbine blades and tooling, preparing them for clamping. Cleaning is to prevent contamination of the parts, which could affect the adhesion of the coating.

[0044] Step 2, Tooling fabrication and clamping: According to Figure 1 The guide vanes to be processed are installed into the outer edge plate protection box 1012 and the inner edge plate protection box 1013, which are connected by high-temperature alloy wire. The outer edge plate protection box 1012 is connected to the tooling connecting rod 1017 by welding, and the tooling connecting rod is connected to the rotating spindle 101 of the equipment by connecting screw 1014.

[0045] Step 3, applying the coating: The specific process of applying the coating is as follows:

[0046] Furnace loading: Connect the device with the turbine working blades to the rotating shaft of the EB-PVD equipment via the connecting rod, start the rotating device, and check whether the rotating system is working properly.

[0047] Vacuuming: Vacuum the loading chamber and sedimentation chamber. When the vacuum level is below 5×10⁻⁶, apply vacuum. -1 At Pa, the blades are fed into the deposition chamber by a servo motor to start heating the parts. When the temperature of the thermocouple in the thermocouple tube reaches the process temperature, the ceramic ingot is heated until the current reaches the process value, and then the coating is deposited.

[0048] Deposited Coating: During the deposition process, to improve the adhesion between the blades and the ferrules, the position of the rotating spindle is controlled to cause the blades to undergo a variable-speed cyclic reciprocating motion along the spindle axis from the initial position "0" to the final position "1". The spindle rotation speed is 10-20 rpm. The parameters for the speed variation of the spindle during the cyclic reciprocating motion along the axis are detailed below. Figure 5 This method improves the adhesion of the rim coating while maintaining the high adhesion of the blade coating. Finally, the coating thickness is controlled by adjusting the consumption of the evaporated ceramic ingots, according to the coating thickness design requirements.

[0049] Cooling: The part is moved to the loading chamber. When the part is vacuum cooled to below 300°C, air is introduced into the loading chamber, the furnace door is opened, and the turbine working blades and tooling are removed. The tooling is removed to obtain turbine working blades with a thermal barrier coating on the entire flow channel surface and effective protection for the non-coated areas.

[0050] The inner and outer edge plates of the guide vane were subjected to microstructural analysis, and the results are as follows: Figure 6 As shown. With Figure 7 Compared to the coating microstructure at the trailing edge of the original process, Figure 6 The columnar crystal structure of the ceramic surface layer in the rim plate area is more obvious, the coating is complete, and it meets the design requirements for the coating structure of the rim plate area.

Claims

1. A process for co-depositing a coating on the blade rim and blade body of a turbine blade, characterized in that, Includes the following steps, Step 1: Install the turbine blades to be processed into the outer edge plate protection box and the inner edge plate protection box; Step 2: Apply a coating to the turbine blades; The specific process of applying the coating includes: The loading chamber and deposition chamber are evacuated. When the vacuum level in the deposition chamber is lower than the threshold, the turbine blades are sent into the deposition chamber by the servo motor to start heating the parts. When the temperature of the thermocouple in the thermocouple tube reaches the process temperature, the ceramic ingot is heated until the current reaches the process value, and then the coating is deposited. During the coating deposition process, the turbine blades are rotated and reciprocated along the main shaft axis from the initial position "0" to the final position "1". The coating thickness is controlled by controlling the consumption of the evaporated ceramic ingots according to the coating thickness design requirements. The turbine blades are moved into the loading chamber and, after cooling, are removed. The turbine blades have a thermal barrier coating on the entire flow channel surface and the non-coated areas are protected. The protective clamp consists of an outer edge plate protective box and an inner edge plate protective box, which are connected by a high-temperature alloy wire. The outer edge plate protective box is connected to the tooling connecting rod by welding, and the tooling connecting rod is connected to the rotating spindle of the equipment by connecting screws. The distance between the initial position "0" and the ending position "1" is 150mm; the speed steps of the rotational speed change are 0-20mm / min, 20-40mm / min, 40-50mm / min, 20-40mm / min, and 0-20mm / min. The initial position "0" refers to the steam cloud formed after the ingot is bombarded and evaporated by the electron beam gun. When the turbine blade, which is clamped in the protective fixture, rotates to the left side of the steam cloud under the drive of the main shaft of the equipment, this position is the initial position "0" of the spatial position between the turbine blade and the steam cloud. The steam formed by the steam cloud forms an angle of more than 20° with the left edge plate of the turbine blade. The terminus "position 1" refers to the steam cloud formed after the ingot is bombarded and evaporated by the electron beam gun. When the turbine blade, which is clamped in the protective fixture, rotates to the right side of the steam cloud under the drive of the main shaft of the equipment, this position is the terminus "position 1" of the spatial position between the turbine blade and the steam cloud. The steam formed by the steam cloud forms an angle of more than 20° with the right edge plate of the turbine blade.

2. The process for co-deposition of a coating on the blade rim and blade body according to claim 1, characterized in that, Before clamping the turbine blades, the turbine blades are cleaned using acetone as the cleaning agent.

3. The process for co-deposition of a coating on the blade rim and blade body according to claim 1, characterized in that, The vacuum threshold is 5×10 -1 Pa.

4. The process for co-deposition of a coating on the blade rim and blade body according to claim 1, characterized in that, During coating deposition, the spindle rotation speed ranges from 10 to 20 rpm.

5. The process for co-deposition of a coating on the blade rim and blade body according to claim 1, characterized in that, During cooling, when the parts are vacuum cooled to below 300°C, air is introduced into the loading chamber, and the furnace door is opened to remove the turbine blades.

6. The process for co-deposition of a coating on the blade rim and blade body according to claim 1, characterized in that, Driven by the rotating main shaft, the turbine blades move non-uniformly from the initial position "0" to the final position "1" along the axis of the main shaft, and then return to the initial position "0" in a non-uniform manner.

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