A turbine rotating blade surface hot film coating lead structure and a preparation method thereof
By using magnetron sputtering technology to form conductive coated leads on the surface of turbine blades, the problems of easy breakage and delamination of traditional wires under high temperature and high speed are solved, and stable electrical connection and comparability of experimental data under complex curved surfaces are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CIVIL AVIATION UNIV OF CHINA
- Filing Date
- 2026-03-18
- Publication Date
- 2026-07-14
Smart Images
Figure CN121852872B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of surface coating and vacuum thin film deposition technology, and relates to the preparation and signal extraction of hot film coating leads in experimental measurements of aero-engines and gas turbines. Specifically, it relates to a hot film coating lead structure on the surface of a turbine rotating blade and its preparation method by magnetron sputtering in-situ deposition. Background Technology
[0002] In aerodynamic experiments on turbine rotor blades of aero-engines and gas turbines, hot film sensors (HFS) are commonly used to accurately obtain unsteady flow parameters on the blade surface. HFS typically outputs electrical signals in isothermal or constant-power operation, and its response is closely related to near-wall velocity gradients, turbulent fluctuations, and local heat transfer conditions. It can provide high-time-resolution observational data for key phenomena such as blade boundary layer transition, separation and reattachment, and secondary flow structures. Most common rotor blade tests are cold-state hot film experiments; for example, fan-stage hot film testing and turbine rotor blade hot film measurements mostly use cold-state experiments. Hot-end experiments applying hot film testing inside rotating turbines are rarely reported. This is mainly because the hot-end test environment involves multiple physical field coupling effects, including high-temperature gradients, strong centrifugal loads, complex vibration spectra, and periodic aerodynamic excitation. This places more stringent reliability requirements on sensor packaging, lead connections, and insulation protection. Any minor lead failure or poor contact can lead to loss of unsteady data, increased signal noise, or measurement drift.
[0003] Current technology involves attaching a thermal film to the blade surface and securing it with adhesive, then leading the wire out from the exposed position along the rotating disk. This traditional method of routing the wire from the sealed position has some inherent drawbacks. To ensure reliability, the wire diameter must be ≥0.5mm. Typically, the seal gap between the rotating and stationary blades is 1.5mm to 2.5mm, meaning the wire can occupy 20% to 40% of the gap. When the wire and its surface encapsulation layer enter this narrow gap area, in addition to occupying geometric margins, it may introduce frictional wear and the risk of localized jamming, leading to repeated compression and bending under the relative displacement between the rotating and stationary blades. Excessively thin wires are prone to breakage, resulting in unreliable experimental results. Excessively large wire diameters, combined with thick adhesive coatings, can cause the wire to crack and open due to axial movement during rotation when passing through the seal gap. Furthermore, under high temperature, high speed, and high centrifugal force, wires attached to the large curvature corners of the blades are prone to delamination, leading to experimental failure. Meanwhile, the manual pasting, wiring, and gluing processes are cumbersome, demanding high skill from operators, and the repeatability between different measuring points and different blades is difficult to guarantee. The process parameters are difficult to standardize and control, resulting in large variations in lead resistance, and making it difficult to effectively guarantee the lateral comparability and experimental repeatability of measurement data between different batches of experimental pieces.
[0004] In summary, existing lead-laying schemes based on adhesive bonding in turbine rotating blade hot film experiments generally suffer from problems such as easy rubbing and squeezing leading to circuit breaks due to large curvature under limited rotor-to-station clearance, easy aging and detachment of adhesive bonding in corner areas under the coupling of thermal cycling and centrifugal loads, and insufficient process consistency and repeatability. Therefore, addressing the aforementioned problems in turbine testing hot film lead-laying, and how to achieve highly reliable hot film signal extraction and stable electrical connection for complex curved surfaces and harsh service environments while meeting rotor-to-station fit and hot-end operating constraints, is an urgent technical problem to be solved. Summary of the Invention
[0005] (a) Purpose of the invention
[0006] To address the problems of wire breakage within narrow gaps in the sealed structure and wire delamination at corners when using existing hot-film lead wiring methods under high temperature and high speed rotation, this invention aims to provide a hot-film coated lead wire structure and preparation method for turbine rotating blade surfaces. The core of this invention lies in abandoning the traditional method of attaching wires to rotor blades. Instead, an insulating layer is first sprayed or deposited at the processing location. Then, magnetron sputtering thin film deposition technology is used to directly form conductive film circuits as signal leads on the surface of the blade substrate using a controllable deposition process, achieving reliable end electrical connections. The thickness of the film lead is 2 to 3 micrometers, ensuring circuit reliability. This effectively reduces the risk of cracking and circuit breakage caused by rubbing, squeezing, and axial movement of the attached wires in the narrow gap between the rotor and stationary seals. It also improves the adhesion stability and conductivity reliability of large curvature corners and complex curved surface areas under high temperature, high speed, and large centrifugal loads, and enhances the consistency and repeatability of the lead preparation process. This enables stable extraction of thermal film signals and comparability of experimental data in complex curved surfaces and seal transition areas. It overcomes the problem that traditional thermal films are prone to substrate melting under high-temperature conditions and can only be tested at low temperatures.
[0007] The experimental measurement object was a turbine blade. A coated lead wire was deposited on the turbine blade surface using magnetron sputtering. Starting from the pin position reserved by the hot-film sensor itself, the lead wire extended along the coated surface of the blade, continuously traversing the aerodynamic surface, blade root, and sealing area, finally terminating near the blade tenon end. The slip ring wire was welded to the coated lead wire for conductivity. The slip ring circuit used conventional routing at the low radius, running from the vent hole in the disk cavity to the slip ring device mounted on the rotating shaft end, reducing centrifugal force and improving reliability under high-speed operation.
[0008] (II) Technical Solution
[0009] To achieve the objective of this invention and solve its technical problems, the present invention adopts the following technical solution:
[0010] The first objective of this invention is to provide a magnetron sputtering in-situ deposition method for preparing a hot-film coating lead wire on the surface of a turbine rotating blade. This method forms a conductive coating lead wire electrically connected to a hot-film sensor pin on the blade surface and extends it to the end of the blade tenon face. The method includes at least the following steps:
[0011] SS1. Blade surface pretreatment: The circuit area to be processed on the surface of the turbine rotating blade is cleaned and activated to obtain a blade substrate surface that meets the requirements for thin film deposition adhesion;
[0012] SS2. Preparation of electrical insulation layer: An electrical insulation layer is formed on the circuit area to be processed on the surface of the blade substrate by spraying or deposition process. The electrical insulation layer covers at least the area where the hot film sensor pin is located and extends continuously to cover the blade root, the transition area between rotating and stationary blades and the end of the tenon face.
[0013] SS3. Lead Mask Design and Installation: Design and fabricate a lead mask with matching geometry according to the position of the hot film sensor pin and the preset lead path, and position and fix the lead mask on the surface of the electrical insulating layer. Define the magnetron sputtering deposition coating area with the opening area of the lead mask, so that the lead path extends continuously from the area where the hot film sensor pin is located to the electrical connection contact point area at the end of the tenon face.
[0014] SS4. Magnetron sputtering deposition of conductive layer: The blade with lead mask is placed in the vacuum chamber of the magnetron sputtering equipment. Copper material is deposited in situ by magnetron sputtering in the mask opening area on the surface of the electrical insulating layer as a functional conductive layer and formed as a continuous coated lead. The coated lead extends from the position of the hot film sensor pin along the aerodynamic surface of the blade, the blade root, and across the sealing transition part of the rotating-stationary blade to the end position of the tenon end face.
[0015] SS5. Thickened deposition of end contacts: At the end of the tenon face where the coated lead extends, copper material is deposited by magnetron sputtering to form an end contact point that is integrally formed with the coated lead. The deposition thickness is greater than that of the main body of the coated lead and has an increased contact area.
[0016] SS6. Mask Removal and Post-processing: Remove the lead mask, and anneal the coated leads and the electrical contact points at the ends of the terminals in a vacuum environment to enhance the adhesion to the electrical insulation layer. Perform electrical continuity and resistance consistency testing, and complete the preparation after passing the test.
[0017] The second objective of this invention is to provide a hot-film coated lead wire structure on the surface of a turbine rotating blade obtained by the above-described preparation method.
[0018] (III) Technical Effects
[0019] Compared with the prior art, the hot film coating lead wire structure and preparation method of the turbine rotating blade surface of the present invention have the following beneficial and significant technical effects:
[0020] (1) The present invention constructs a conductive coating wire with a thickness of micron by magnetron sputtering in situ deposition on the blade surface and continuously leads it out along the aerodynamic surface, blade root and sealing transition area to the end of the tenon end face. Since the thickness of the coating wire is usually between 2 and 3 microns, the geometric occupancy of the wire is significantly reduced in the scenario where the rotor-stationary clearance is limited. Even if the rotor axial movement occurs during high-speed rotation, the wire will not be scratched and broken, thereby improving the reliability of the hot film signal extraction and the continuity of the test.
[0021] (2) In view of the huge centrifugal force that the blades bear under the condition of tens of thousands of revolutions per minute, the present invention has optimized the disadvantage that the wires are easy to debond in stress concentration areas such as corners and roots of the blade surface under high temperature environment. The magnetron sputtering film and the blade substrate are molecular-scale bonded, with extremely strong adhesion, which can withstand high temperature and high speed, avoiding problems such as wire falling off. It can also ensure the consistency of circuit performance between different blades and different batches of experimental pieces, ensuring the comparability and repeatability of experimental data.
[0022] (3) The present invention integrates the lead start area, the main body area and the end face electrical connection contact area into one piece. The end face contact increases the contact area to adapt to welding conduction. It also cooperates with electrical continuity and resistance consistency detection to realize process quality closed loop, so that the circuit geometry and electrical characteristics between different measuring points and different blade test pieces can be repeated and traced, improving batch consistency and comparability of multi-point synchronous measurement data. Attached Figure Description
[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood in conjunction with the following description of the embodiments, in which:
[0024] Figure 1 The diagram shows the implementation flow of the magnetron sputtering in-situ deposition method for preparing thermal film coating leads on the surface of turbine rotating blades according to an embodiment of the present invention.
[0025] Figure 2 The diagram shows the hot film coating lead wire structure on the surface of the turbine rotating blade, where: (a) is a front view of a single-stage turbine, (b) is a cross-sectional view of the single-stage turbine along the AA direction, and (c) is a partially enlarged schematic diagram of the transition position between the rotating and stationary blades at region B.
[0026] Figure 3 The diagram shows the layout of the lead wires for the sealing transition and the tenon end face. (a) is a schematic diagram of the lead wire layout at the sealing transition position, (b) is a partial enlarged schematic diagram of area C, (c) is a schematic diagram of the lead wire layout at the tenon end face, and (d) is a partial enlarged schematic diagram of area D.
[0027] Explanation of reference numerals in the attached diagram: 1-coating lead wire, 2-stationary blade, 3-transition structure for sealing between the rotating and stationary blades. Detailed Implementation
[0028] This invention aims to provide a conductive coated lead wire structure and preparation method for a turbine rotating blade surface, which is used to form a conductive coated lead wire electrically connected to the pins of a thermal film sensor on the surface of the turbine rotating blade and lead the conductive coated lead wire to the end of the blade tenon face, so as to meet the requirements for stable signal output under conditions of limited rotor-to-stationary clearance and coupling of thermal cycling and centrifugal load. To make the technical solution and advantages of this invention clearer, the technical solution of this invention will be described in more detail below with reference to the accompanying drawings of the embodiments of this invention. The described embodiments are some embodiments of this invention, but not all embodiments, and are exemplary, intended to explain this invention, and should not be construed as limiting this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0029] It should be noted that the "sealing transition area" mentioned in this article refers to the geometric transition and small gap sensitive area near the sealing structure between the rotating blade and the stationary component. This invention reduces the risk of scratches by controlling the thickness and deposition posture of the thin film deposited in situ by magnetron sputtering.
[0030] Example 1: Method for preparing lead wires for hot film coating on turbine blade surface
[0031] As a specific example, such as Figure 1 As shown, the magnetron sputtering in-situ deposition method for preparing hot-film coating leads on the surface of turbine rotating blades provided in this embodiment of the invention focuses on the construction of an electrically insulating substrate, the definition of a mask pattern, and vacuum in-situ deposition forming, and mainly includes the following steps:
[0032] SS1. Blade surface pretreatment:
[0033] The surface of the turbine blades to be processed circuit areas is cleaned and activated to obtain a blade substrate surface that meets the requirements for thin film deposition. Specifically, microscopic contaminants are removed through physical roughening and chemical cleaning, and high-energy activation states are induced by plasma bombardment to improve interfacial wettability and enhance the interfacial bonding strength and anti-peeling stability of the subsequent electrical insulation layer.
[0034] Preferably, the cleaning and activation process includes at least the following sub-steps in sequence:
[0035] S101 Surface roughening treatment: Sandblasting is used to roughen the circuit area to be processed on the surface of the blade substrate. The sandblasting medium is white corundum sand or glass microspheres with a particle size of 180~320 mesh. The sandblasting air pressure is controlled within the range of 0.2~0.5 MPa. After sandblasting, the surface roughness Ra of the blade substrate is controlled within the range of 0.4~1.6 μm, so as to form a uniform micro-roughness on the surface, thereby improving the mechanical interlocking ability and adhesion stability of the subsequent electrical insulation layer and conductive layer.
[0036] S102 Organic Degreasing Cleaning: The roughened blade substrate surface is ultrasonically immersed in an organic solvent to remove grease and particulate contaminants. The ultrasonic cleaning frequency is not less than 40 kHz and the immersion time is not less than 15 min. The cleaning solvent is sequentially replaced by acetone and anhydrous ethanol in a two-step process. After immersion, solvent replacement and drainage are performed to reduce the impact of residual solvent on subsequent film formation.
[0037] S103 Deionized water rinsing: Deionized water is used to rinse the surface of the blade substrate after degreasing treatment to remove soluble residues and fine particles carried by solvent, and the rinsing time is controlled to ensure that the surface ion residue meets the cleanliness requirements for thin film deposition.
[0038] S104 Drying and dehumidification treatment: Dry the surface of the blade substrate after rinsing. It is preferred to use clean hot air circulation or infrared heating. The drying temperature is controlled within the range of 60℃ to 80℃ and the drying time is not less than 30 minutes. The surface of the circuit area to be processed is in a state with no visible water film and controlled moisture content to avoid moisture precipitation in the vacuum environment and causing interface defects.
[0039] S105 Surface Activation Treatment: After drying, the blades are placed in a plasma cleaning device, and the surface of the dried blade substrate is activated by plasma bombardment using argon or an argon-oxygen mixture as the working medium. The plasma power density is not less than 0.5 W / cm². 2 The working air pressure is controlled within the range of 10~50 Pa, and the activation time is not less than 10 min, so as to form an activated state with high surface energy on the surface of the blade substrate, ensuring that the adhesion performance of the subsequent electrical insulation layer meets the process requirements.
[0040] SS2. Preparation of the electrical insulation layer:
[0041] An electrically insulating layer is formed on the surface of the blade substrate in the area to be processed by spraying or deposition. The electrically insulating layer covers at least the area where the hot film sensor pin is located and extends continuously to cover the blade root, the transition area between rotating and stationary blades, and the end of the tenon face.
[0042] Preferably, the electrical insulation layer is prepared using either plasma spraying or physical vapor deposition (PVD). The choice of process method is determined based on a combination of the geometric complexity of the lead path and the required insulation layer thickness: plasma spraying is preferred for areas with relatively flat surfaces and high insulation layer thickness requirements; physical vapor deposition is preferred for geometrically complex curved surfaces such as the large curvature transition area at the blade root and the sealing transition area, to leverage its superior three-dimensional surface conforming ability and thickness uniformity. The material for the electrical insulation layer is selected from at least one of magnesium oxide, silicon oxide, or zirconium oxide. The specific selection of the electrical insulation layer material comprehensively considers the matching of the thermal expansion coefficient with the nickel-based superalloy substrate of the blade, the insulation strength requirements within the operating temperature range, and the chemical compatibility with the interface of the subsequent conductive layer. Magnesium oxide is the preferred material due to its balance of insulation performance and thermal stability. The deposition thickness is controlled at 1 mm. Within the μm range, and in the transition area of large curvature at the blade root and the transition area of the rotating-stationary blade sealing, the spraying angle or sputtering substrate posture is adjusted in segments to ensure that the electrical insulation layer has a uniform thickness and uninterrupted coverage in the curvature change area, thus ensuring the electrical insulation reliability of the subsequent conductive coating lead throughout the entire process.
[0043] It should be noted that the continuity of the electrical insulation layer and the reliability of the insulation are key prerequisites for achieving stable electrical isolation in multi-channel coated leads. This invention addresses the issues of missed coating and thinning at geometrically abrupt transition points such as the high curvature transition zone at the blade root and the transition zone between rotation and stationary sealing by segmented adaptive adjustment of the spraying angle or sputtering substrate posture. This ensures uninterrupted continuous coverage of the insulation layer throughout the entire lead path. Compared to traditional film lamination or manual insulation coating methods, this step employs an in-situ film formation process, giving the insulation layer superior three-dimensional surface conformability and high-temperature adhesion stability, effectively avoiding the risk of short circuits between the conductive layer and the blade metal substrate caused by local defects in the insulation layer.
[0044] SS3. Lead Mask Design and Installation:
[0045] Design and fabricate a lead mask with matching geometry based on the pin position of the hot film sensor and the preset lead path, and position and fix the lead mask on the surface of the electrical insulating layer. Define the magnetron sputtering deposition coating area with the opening area of the lead mask, so that the lead path extends continuously from the area where the hot film sensor pin is located to the electrical connection contact point area at the end of the tenon end face.
[0046] Preferably, in step SS3, the lead mask is made of a metal sheet or a high-temperature resistant polyimide film with good shape memory and sputter damage resistance, with a thickness controlled within the range of 0.05~0.3 mm, to simultaneously ensure the clarity of the opening area edge and the conformity of the mask to the blade surface. During mask installation, the mask is precisely aligned with the preset reference alignment mark on the blade surface using a positioning fixture, with a positioning accuracy of not less than ±0.05 mm. The local bonding gap between the mask and the surface of the electrical insulation layer does not exceed 0.01 mm to prevent sputtering particles from diffracting and causing blurring of the lead boundary and linewidth deviation. In addition, the opening area of the lead mask includes at least the lead starting area corresponding to the hot-film sensor pin, the lead body area extending along the preset lead path, and the electrical connection contact point area located at the end of the tenon end face. The geometric dimensions of the electrical connection contact point area at the end face are larger than the linewidth dimensions corresponding to the lead body area to meet the requirements of subsequent... In magnetron sputtering deposition, the end face electrical contact points required for welding connection are integrally formed, ensuring the linear continuity and boundary clarity of the lead body area. Furthermore, for multiple coated leads corresponding to multiple thermal film sensors on the same blade, an electrical isolation spacing design principle is adopted. The minimum spacing between adjacent leads is determined based on the maximum applied test voltage and the surface resistivity of the electrical insulation layer, and is not less than 0.3 mm. Multiple leads are arranged in a comb-like pattern at equal intervals in the blade root platform area and converge towards the tenon end face. At the end of the tenon end face, a numbered and identified multi-contact terminal area is formed in an array to realize the synchronous parallel output of multi-channel thermal film sensor signals, meeting the engineering application requirements of multi-point synchronous measurement on the blade surface.
[0047] It should be noted that the precision and positioning accuracy of the lead mask pattern directly determine the linear continuity and multi-channel electrical isolation quality of the coated leads. This invention integrates the lead body area, end-face contact extension area, and sensor pin start area into a unified mask pattern, achieving precise patterned deposition of the entire lead through a single alignment, eliminating the cumulative effect of positional deviations from step-by-step alignment; the quantitative design method of isolation spacing based on the surface resistivity of the insulating layer provides a quantitative electrical safety margin for multi-channel parallel lead-out; and the numbering scheme for the multi-contact array on the tenon end face effectively improves the recognition efficiency of parallel lead-out of multiple sensor signals.
[0048] SS4. Magnetron sputtering deposition of conductive layer:
[0049] The blade with the lead mask is placed in the vacuum chamber of the magnetron sputtering equipment. Copper material is deposited in situ by magnetron sputtering in the mask opening area on the surface of the electrically insulating layer as a functional conductive layer and formed as a continuous coated lead. The coated lead extends from the position of the hot film sensor pin along the aerodynamic surface of the blade, the blade root, and across the transition area between the rotating and stationary blades to the end position of the tenon end face.
[0050] Preferably, in step SS4, before sputtering and depositing the functional conductive layer of copper material, a metal attachment transition layer is first formed on the surface of the electrical insulating layer. The metal attachment transition layer is deposited in situ and continuously formed in the mask opening area by magnetron sputtering under vacuum environment, and is integrally formed with the subsequently deposited functional conductive layer of copper material in the same pattern range. The material is selected from at least one of titanium, chromium or nickel, and its film thickness is less than a preset ratio of the film thickness of the functional conductive layer of copper material. This is to improve the interfacial bonding strength of the functional conductive layer of copper material on the surface of the electrical insulating layer without reducing the electrical isolation performance of the electrical insulating layer, and to reduce the risk of interfacial peeling and conduction degradation under thermal cycling, vibration and centrifugal load. After the metal attachment transition layer is formed, its surface is cleaned and dried, and the copper material is deposited by magnetron sputtering while maintaining the lead mask positioning state and without destroying the vacuum condition, so as to obtain a continuously extending coated lead along the preset lead path and the end face electrical connection contact point.
[0051] More preferably, the functional conductive layer of copper material deposited in situ by magnetron sputtering includes at least:
[0052] S401. Vacuum Loading and Cavity Stabilization: Fix the blades equipped with the lead mask inside the vacuum chamber of the magnetron sputtering equipment, ensuring the surface to be deposited faces the sputtering target and that the mask opening area does not shift relative to the target. Evacuate the vacuum chamber and stabilize it to meet the working vacuum conditions for sputtering deposition, with a base vacuum level better than 5 × 10⁻⁶. -4 Pa ensures that residual gas does not contaminate the purity of the copper film or the adhesion interface;
[0053] S402. Bombardment cleaning and surface activation: High-purity argon gas (argon purity not less than 99.999%, working pressure adjusted to 0.5~2 Pa) is introduced into the vacuum chamber. A DC negative bias voltage is applied to the blade substrate (the bias voltage value is preferably controlled within the range of -100~-300 V). In-situ bombardment cleaning is performed on the surface of the electrical insulation layer in the mask opening area (bombardment cleaning time is preferably not less than 5 min) to remove the weak adsorption layer, so that the surface of the electrical insulation layer is restored to a high surface energy activated state, creating clean physicochemical conditions for the subsequent bonding of the transition layer and / or copper functional conductive layer.
[0054] S403. In-situ deposition of copper functional conductive layer: Using a copper target with a purity of not less than 99.99% as the sputtering source, high-purity argon as the sputtering working gas, and maintaining the blade substrate temperature below 100℃, the magnetron sputtering deposition process is initiated, with the sputtering power density controlled at 2~8 W / cm². 2Within the range, the working gas pressure is maintained in the range of 0.3~1.0 Pa, and the deposition rate is controlled in the range of 0.1~0.5 μm / min. While ensuring the density of the film, the deposition thermal effect is suppressed. Copper material is deposited in situ in the mask opening area on the surface of the electrical insulating layer to form a copper film. A continuous coated lead wire is obtained from the position of the hot film sensor pin along the aerodynamic surface of the blade, the blade root, and across the sealing transition part of the rotating and stationary blade to the end position of the tenon end face.
[0055] S404. Attitude control and continuous deposition: During the deposition process in the high curvature transition zone of the blade root platform and the sealing transition zone of the rotating-stationary blade, the blade is subjected to a composite motion control of rotation and translation relative to the sputtering target. The rotation angle of the blade around the chordal axis perpendicular to the blade covers a range of not less than ±30° of the normal direction of the curved surface. The rotation angular velocity and translation velocity are coordinated and matched to maintain the uniform deposition rate at each position, thereby changing the relative incident direction of sputtering particles and reducing the shadowing effect. This ensures that sputtering particles are uniformly incident and deposited on the corner curved surface, so that the copper film is continuously deposited in the high curvature area to form an electrical interconnection path.
[0056] S405. Film thickness control and sealing transition area adaptation: During the deposition process, the deposition time or deposition rate is controlled to keep the copper film thickness of the main body of the coated lead within the range of 2~3 μm, and the total thickness of the coated lead crossing the sealing transition area of the rotating-stationary blade is controlled to be less than 5% of the sealing gap size, so as to reduce the risk of scraping and breakage caused by axial movement during the rotation process.
[0057] S406. Termination of Deposition and Cooling Unloading: After reaching the target film thickness, terminate magnetron sputtering deposition and perform controlled cooling on the blades. The cooling rate shall not exceed 5°C / min. After cooling to room temperature, hold the pressure in the vacuum chamber for no less than 10 minutes to keep the residual stress of the film under control. Then, while maintaining the mask positioning, complete the unloading and transfer to the subsequent contact thickening deposition step.
[0058] It should be noted that during the deposition of the conductive layer, the working pressure, target-substrate distance, and substrate temperature should be controlled to stabilize the sputtering particle energy and film density. Target cleaning and in-situ bombardment cleaning of the substrate should be performed before deposition to improve interface cleanliness. During deposition, a combination of rotation and translational attitude control should be used to weaken the shadowing effect. Film thickness can be controlled through process control of deposition time or rate, resulting in uniform resistance distribution throughout the entire path, controlled residual stress, and reduced likelihood of microcracks.
[0059] SS5. Thickened deposition at the end contact:
[0060] At the end of the tenon face where the coated lead extends, copper material is deposited by magnetron sputtering to form an end face electrical contact point integrally formed with the coated lead. The deposition thickness is greater than that of the main body of the coated lead and has an increased contact area.
[0061] Preferably, in step SS5, the end face electrical contact point is formed by a staged thickening deposition method: first, a contact base layer is formed under the same process conditions as the coated lead body; then, while keeping the lead mask positioning unchanged and ensuring that the deposition window in the contact area does not shift, additional magnetron sputtering deposition is performed only on the contact area. The deposition thickness of the contact area is greater than that of the coated lead body, which also increases the contact area. After the additional deposition is completed, the contact area and the coated lead body form an integral continuous conductive structure to meet the consistency requirements of contact stability, vibration resistance reliability, and assembly identification during subsequent welding.
[0062] Furthermore, after completing the deposition of the end-face electrical connection contact point, a silicon nitride or aluminum oxide thin film is deposited in situ on the exposed copper layer surface of the main body of the coated lead as a conductive protective coating. The deposition thickness of the protective coating is controlled at 200~800 nm to achieve effective anti-oxidation protection while avoiding the risk of cracking and peeling caused by thermal expansion mismatch due to excessively thick coating. The protective coating continuously covers the lead path of the main body of the coated lead, and a coating shielding boundary is set in the end-face electrical connection contact point area to ensure that the protective coating does not cover the conductive contact surface of the end-face electrical connection contact point. This prevents the conductive performance of the coated copper lead from degrading due to high-temperature oxidation or airflow erosion during blade service, thereby significantly improving the environmental stability and long-term reliability of the coated lead without affecting the electrical connection operation of the signal output end.
[0063] It should be noted that the phased thickening deposition design of the end face electrical contact point and the selective in-situ covering of the protective coating together constitute the reliability assurance mechanism of the coated lead end. The former achieves the integral and continuous forming of the contact and lead body while maintaining the mask positioning, eliminating the risk of weak interface bonding caused by phased deposition; the latter retains the exposed conductivity of the contact area while implementing anti-oxidation protection for the lead body, effectively balancing the design contradiction between the high-temperature durability of the coated lead and the ease of operation of the end electrical connection, which is of great significance for improving the long-term service reliability of the blade rotation measurement system.
[0064] SS6. Mask Removal and Post-processing:
[0065] Remove the lead mask, and anneal the coated leads and the electrical contact area at the end face in a vacuum environment to enhance the adhesion with the electrical insulation layer. Then, complete the electrical continuity and resistance consistency test. After passing the test, the preparation is complete.
[0066] Preferably, in step SS6, the annealing process is carried out in a vacuum environment and includes at least the following steps: placing the demasked blade in a vacuum annealing apparatus and evacuating it to a vacuum level that meets the annealing requirements; the annealing vacuum level should be better than 1×10⁻⁶.-3 Pa is used to prevent high-temperature oxidation of the copper film during heating, which would lead to degradation of its conductivity. The blade is heated under vacuum conditions at a rate of 3-8 °C / min to bring the main body of the coated lead and the electrical contact area at the end face to the preset annealing temperature (150-350 °C to ensure the elimination of residual stress and grain refinement of the copper film while avoiding the thermal impact on the microstructure of the nickel-based superalloy substrate of the blade) and held for a preset holding time (30-120 min) to eliminate residual stress in the film deposition and enhance the interfacial bonding between the conductive layer and the electrical insulating layer. Subsequently, controlled cooling is performed under vacuum conditions at a rate not exceeding 5 °C / min to cool the blade to the preset temperature before it is removed from the furnace. After annealing, electrical continuity is tested along the entire path of the coated lead, and resistance consistency is tested at multiple test locations to determine whether the conduction state and resistance stability before and after annealing meet the preparation requirements.
[0067] Furthermore, the electrical continuity and resistance consistency detection includes at least the following: for each coated lead, multiple detection nodes are set along the entire path from the location of the thermal film sensor pin to the electrical connection contact point at the end of the tenon face. A combination of continuity testing and loop resistance testing is used to verify that the coated lead does not have open circuits, broken bands, or local non-conductive areas. The coated lead is divided into at least three test sections: the lead start area, the lead body area, and the electrical connection contact point area at the end of the face. The resistance value of each section is measured, and the resistance difference between sections is calculated to determine that the uniformity of the resistance distribution along the path of the coated lead meets the consistency requirements. Preferably, the ratio of the maximum to the minimum measured value of the total loop resistance of all coated leads on the same blade does not exceed 1.5, and the deviation of the total loop resistance value of any coated lead from the nominal design value does not exceed ±20%, to quantitatively determine the lead resistance consistency. The preparation is deemed qualified when the electrical continuity test is passed and the segmented resistance consistency meets the preset threshold conditions.
[0068] In addition, after the annealing process is completed and the test is qualified, the process also includes welding the end contact points of the external test signal wire and the coating lead wire to make them electrically connected, and attaching the welded external test signal wire to the disk wall and passing it through the vent hole of the disk cavity to the shaft end slip ring position, forming an electrical connection path for the measurement signal of the rotating component to be transmitted to the external test system, so as to realize the stable transmission and output of the thermal film signal.
[0069] It should be noted that this embodiment uses the surface of a turbine blade as the supporting substrate. Through the coordinated integration of processes such as blade surface pretreatment, electrical insulation layer preparation, patterned mask design and installation, in-situ deposition of a copper conductive layer by magnetron sputtering, end-face contact thickening, and post-annealing treatment, a continuous conductive path from the pin of the thermal film sensor to the electrical connection point at the end of the tenon end face is achieved. The process parameters of each step are coordinated and constrained to form a complete engineering implementation scheme suitable for the complex curved surface of a turbine blade, providing a reliable signal transmission basis for the synchronous measurement of multi-point dynamic thermal parameters on the blade surface.
[0070] Example 2: Turbine Rotating Blade Surface Thermal Film Coating Lead Wire Structure
[0071] Based on the preparation method of Example 1 above, Example 2 further provides a hot film coating lead structure and its signal lead-out layout on the surface of the turbine rotating blade obtained by the preparation method, so as to realize that the coating lead crosses the sealing transition position of the rotating and stationary blades and forms a weldable electrical connection contact point at the end of the tenon end face.
[0072] like Figure 2 As shown, the coating lead 1 is continuously laid along the surface of the turbine blade. At the blade root corner, it changes with the shape of the root chamfer and is tightly integrated with the blade root without being suspended or raised. Then it passes around the blade root platform and through the rotating-stationary blade sealing transition structure 3 constructed at the end of the stationary blade 2, and finally reaches the tenon end face, rather than the mortise and tenon position. The coating lead is thickened and enlarged at the end, thus structurally avoiding the clamping damage and assembly interference risk caused by the mortise and tenon assembly mating face to the coating lead.
[0073] like Figure 3 As shown, the coated lead wire 1 is led out from the blade surface and splits into two strands, distinguished by the direction of flow: upstream is the front, and downstream is the rear. One strand reaches the front end of the tenon, and the other reaches the rear end. The ends of both coated lead wires are thickened to form thickened contacts, ensuring that the contact area meets the process requirements for welding continuity. After the contacts are formed, the test signal wire is connected to the ends of the coated lead wires via welding. The signal wire is laid along the rotating disk, passes through the vent holes on the disk, reaches the shaft end, and connects to the external testing system through a slip ring device, thus forming a system-level output path for the measurement signal of the rotating component. The above structural layout fully combines the geometric space constraints of the turbine rotating component with the actual engineering requirements for outputting rotating mechanical signals, achieving a balance between the functional reliability and assembly coordination of the coated lead wire structure under high-speed rotation, vibration, and thermal shock environments.
[0074] The objectives of this invention have been fully and effectively achieved through the above embodiments. Those skilled in the art will understand that this invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments described above. Although the invention has been described with reference to what is currently considered the most practical and preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments, and any modifications that do not depart from the functional and structural principles of the invention will be included within the scope of the claims.
Claims
1. A method for preparing a hot-film coating lead wire on the surface of a turbine rotating blade by magnetron sputtering in-situ deposition, characterized in that, At least the following steps are included: SS1. The circuit area to be processed on the surface of the turbine blade is cleaned and activated to obtain a blade substrate surface that meets the requirements for thin film deposition adhesion; SS2. An electrically insulating layer is formed on the surface of the blade substrate in the area to be processed by spraying or deposition, covering the area where the hot film sensor pins are located and continuously extending to the blade root, the transition area between rotating and stationary blades and the end of the tenon face; SS3. Design and fabricate a lead mask with matching geometry based on the position of the hot film sensor pin and the preset lead path, and position and fix the lead mask on the surface of the electrical insulating layer. Define the magnetron sputtering deposition area with the opening area of the lead mask, so that the lead path extends continuously from the area where the hot film sensor pin is located to the electrical connection contact point area at the end of the tenon face. SS4. Place the blade equipped with the lead mask in the vacuum chamber of the magnetron sputtering equipment. Magnetron sputtering is used to deposit copper material in situ as a functional conductive layer in the mask opening area on the surface of the electrically insulating layer, forming a continuous coated lead. The coated lead extends from the position of the hot-film sensor pin along the aerodynamic surface of the blade, through the blade root, and across the transition area between the rotating and stationary blades to the end of the tenon face. During the deposition process in the high-curvature transition area of the blade root platform and the transition area between the rotating and stationary blades, a composite motion control of rotation and translation relative to the sputtering target is implemented. The rotation angle of the blade around the chordal axis perpendicular to the blade covers a range not less than ±30° of the normal direction of the curved surface, ensuring uniform incident deposition of sputtered particles onto the corner curved surface. Furthermore, the deposition time or deposition rate is controlled to keep the copper film thickness of the main body of the coated lead within the range of 2~3 μm, and the total thickness of the coated lead across the transition area between the rotating and stationary blades is less than 5% of the sealing gap size. SS5. At the end of the coated lead extending to the tenon end face, copper material is deposited by magnetron sputtering to form an end face electrical contact point integrally formed with the coated lead. The deposition thickness is greater than that of the main body of the coated lead and has an increased contact area. The end face electrical contact point is formed by a staged thickening deposition method. First, a contact base layer is formed under the same process conditions as the main body of the coated lead. Then, while keeping the lead mask positioning unchanged and the deposition window in the contact area does not shift, additional magnetron sputtering deposition is performed only on the contact area, so that the deposition thickness of the contact area is greater than that of the main body of the coated lead, and the contact area has an increased contact area. After the additional deposition is completed, the contact area and the main body of the coated lead form an integrally formed continuous conductive structure. SS6. Remove the lead mask, anneal the coated leads and the electrical connection contact area at the end face, and complete the electrical continuity and resistance consistency test. After passing the test, the preparation is complete.
2. The preparation method according to claim 1, characterized in that, In step SS1, the cleaning and activation process includes at least the following sub-steps in sequence: S101 Surface roughening treatment: Sandblasting process is used to roughen the circuit area to be processed on the surface of the blade substrate; S102 Organic degreasing cleaning: The roughened blade substrate surface is ultrasonically immersed in organic solvent, and solvent replacement and drainage are performed after immersion. S103 Deionized water rinsing: Deionized water is used to rinse the surface of the blade substrate after degreasing treatment, and the rinsing time is controlled so that the surface ion residue meets the cleanliness requirements for thin film deposition. S104 Drying and dehumidification treatment: The surface of the blade substrate after rinsing is dried so that the surface of the circuit area to be processed reaches a state where there is no visible water film and the moisture content is controlled. S105 Surface activation treatment: After drying, the blade is placed in a plasma cleaning device, and the surface of the blade substrate is activated by plasma bombardment using argon or argon-oxygen mixed gas as the working medium to form an activated state with high surface energy on the blade substrate surface.
3. The preparation method according to claim 1, characterized in that, In step SS2, the electrical insulation layer is prepared by plasma spraying or physical vapor deposition. The material is selected from magnesium oxide, silicon oxide or zirconium oxide. The deposition thickness is controlled within 1 μm. In the large curvature transition area of the blade root and the sealing transition area of the rotating-stationary blade, the spraying angle or sputtering substrate attitude is adjusted in segments to ensure that the electrical insulation layer has a uniform thickness and uninterrupted coverage in the curvature change area.
4. The preparation method according to claim 1, characterized in that, In step SS3, the opening area of the lead mask includes at least a lead starting area corresponding to the hot-film sensor pin, a lead body area extending along a preset lead path, and an electrical connection contact point area located at the end of the tenon end face. The geometric dimensions of the electrical connection contact point area at the end face are larger than the corresponding dimensions of the lead body area. Furthermore, for multiple coated leads corresponding to multiple hot-film sensors on the same blade, an electrical isolation spacing design principle is adopted. The minimum spacing between adjacent leads is determined based on the maximum applied test voltage and the surface resistivity of the electrical insulation layer and is not less than 0.3 mm. Multiple leads are arranged in a comb-like pattern at equal intervals in the blade root platform area and converge toward the tenon end face. At the end of the tenon end face, a numbered multi-contact terminal area is formed in an array.
5. The preparation method according to claim 1, characterized in that, In step SS4, before sputtering and depositing the functional conductive layer of copper material, a metal attachment transition layer is first formed on the surface of the electrically insulating layer. The transition layer is deposited in situ and continuously formed in the mask opening area by magnetron sputtering under vacuum environment, and is integrally formed with the subsequently deposited functional conductive layer of copper material in the same pattern range. The material is selected from at least one of titanium, chromium or nickel, and its film thickness is less than a preset ratio of the film thickness of the functional conductive layer of copper material. After the transition layer is formed, its surface is cleaned and dried, and the copper material is deposited by magnetron sputtering while maintaining the lead mask positioning state and without destroying the vacuum condition.
6. The preparation method according to claim 1 or 5, characterized in that, In step SS4, the in-situ deposition of a functional conductive layer of copper material by magnetron sputtering includes at least the following sub-steps: S401. Vacuum loading and cavity stabilization: Fix the blade with the lead mask in the vacuum cavity of the magnetron sputtering equipment, so that the surface to be deposited faces the sputtering target and the mask opening area does not move relative to the target. Evacuate the vacuum cavity and stabilize it to meet the working vacuum conditions for sputtering deposition. S402. Bombardment cleaning and surface activation: High-purity argon gas is introduced into the vacuum chamber, a DC negative bias voltage is applied to the blade substrate, and in-situ bombardment cleaning is performed on the surface of the electrical insulation layer in the mask opening area to remove the weak adsorption layer and restore the surface of the electrical insulation layer to a high surface energy activated state. S403. In-situ deposition of copper functional conductive layer: using a copper target with a purity of not less than 99.99% as the sputtering source and high-purity argon as the sputtering working gas, the magnetron sputtering deposition process is started to deposit copper material in-situ in the mask opening area on the surface of the electrical insulating layer to form a copper thin film. S404. Attitude control and continuous deposition: During the deposition process in the high curvature transition zone of the blade root platform and the transition zone between rotating and stationary blades, the blades are subjected to a composite motion control of rotation and translation relative to the sputtering target to ensure uniform incident deposition of sputtering particles on the corner curved surface. S405. Film Thickness Control and Sealing Transition Area Adaptation: Control the deposition time or deposition rate to keep the copper film thickness of the main body of the coated lead within the range of 2~3 μm, and control the total thickness of the coated lead crossing the sealing transition area of the rotor-stationary blade to be less than 5% of the sealing gap size; S406. Termination of Deposition and Cooling Unloading: After the target film thickness is reached, magnetron sputtering deposition is terminated and the blades are subjected to controlled cooling to keep the residual stress of the film under control.
7. The preparation method according to claim 1, characterized in that, After completing the deposition of the end-face electrical connection contact point in step SS5, a silicon nitride or aluminum oxide thin film is deposited in situ on the exposed copper layer surface of the main body of the coated lead as a conductive protective coating. The protective coating continuously covers the lead path of the main body of the coated lead. At the same time, a coating shielding boundary is set in the end-face electrical connection contact point area to ensure that the protective coating does not cover the conductive contact surface of the end-face electrical connection contact point.
8. The preparation method according to claim 1, characterized in that, In step SS6, the annealing process includes at least the following: placing the demasked blade in a vacuum annealing apparatus and evacuating it to the required vacuum conditions; heating the blade under vacuum conditions to bring the main body of the coated lead and the electrical contact point at the end face to a preset annealing temperature and maintaining the temperature for a preset duration; then subjecting the blade to controlled cooling under vacuum conditions to cool it to the preset temperature before removing it from the furnace; and after annealing, performing electrical continuity testing on the entire path of the coated lead and resistance consistency testing at multiple testing locations to determine whether the conduction state and resistance stability before and after annealing meet the preparation requirements.
9. The preparation method according to claim 1 or 8, characterized in that, In step SS6, the electrical continuity and resistance consistency detection includes at least the following: for each coated lead, multiple detection nodes are set along the entire path from the location of the thermal film sensor pin to the electrical connection contact point at the end of the tenon face; a combination of continuity testing and loop resistance testing is used to verify that the coated lead does not have open circuits, broken bands, or local non-conductive areas; the coated lead is divided into at least three test sections according to the lead start area, the lead body area, and the electrical connection contact point area at the end of the face; the resistance value of each section is measured and the resistance difference between sections is calculated to determine that the uniformity of the resistance distribution along the path of the coated lead meets the consistency requirements; when the electrical continuity test is qualified and the segment resistance consistency meets the preset threshold conditions, the preparation is deemed qualified.
10. The preparation method according to claim 1, characterized in that, Step SS6, after the annealing process is completed and the test is passed, also includes welding the end contact points of the external test signal wire and the coating lead wire to make them conductive. The welded external test signal wire is then attached to the disk wall and passes through the vent hole in the disk cavity to the slip ring position at the shaft end, forming an electrical connection path for the measurement signal of the rotating component to be transmitted to the external test system, thereby realizing the stable transmission and system-level output of the thermal film signal.
11. A heat-film coated lead wire structure on the surface of a turbine rotating blade obtained by the preparation method according to any one of claims 1 to 10.