High temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions and preparation method thereof

Abstract

The present invention discloses a high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions and a preparation method thereof. The high temperature resistant thin film sensor comprises a substrate and a high temperature glue layer, a Ta2O5 thin film layer and a SiO2 thin film layer arranged on its surface, as well as a first thin film thermocouple, a thermocouple stack and a strain sensitive grid, and the surface is covered with a protective layer. The preparation method thereof comprises: preparing the above-mentioned thin film layers on the surface of the substrate. Compared with conventional high temperature resistant thin film sensors, the high temperature resistant thin film sensor of the present invention has more excellent high temperature resistance and structural stability, longer service life, higher measurement accuracy, and can be used to measure the working parameters (such as temperature, strain, heat flow, etc.) of turbine blades at high working temperature and high speed at the same time. It has high use value and good application prospects. The preparation method thereof has the advantages of simple process, convenient operation, low preparation cost, high yield rate, etc., is suitable for large-scale preparation, and is conducive to industrial application.

Description

Technical Field

[0001] The present invention belongs to the technical field of thin film sensors, and relates to a high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions and a preparation method thereof. Background Art

[0002] With the continuous improvement of the thrust-to-weight ratio of aircraft engines and the continuous improvement of the power of heavy-duty gas turbines, the speed and operating temperature of the turbine blades of the unit are also getting higher and higher. Generally speaking, the operating temperature of the turbine blades is as high as or even exceeds 1100℃, and the speed is as high as 20,000 rpm or higher, which puts higher requirements on the monitoring of the blade working parameters (temperature, strain, heat flow, etc.). At present, temperature film sensors, pressure film sensors and heat flow film sensors are often used to monitor the temperature, strain and heat flow of the blades. However, due to the poor adhesion of the insulation layer in the existing film sensors, it is easy to break or fall off under high temperature conditions. This makes the existing film sensors still have defects such as poor high temperature resistance, poor stability and short service life. It cannot meet the current measurement requirements of turbine blades at high operating temperatures and high speeds. It is not only not conducive to obtaining accurate measurement accuracy, but also may cause serious damage to the performance and life of the engine / turbine, and it is difficult to ensure their safety. In addition, for thin film sensors with temperature, strain and heat flow measurement functions, due to the limited size of the blade surface, higher requirements are placed on the preparation process of the insulating layer and the functional film layer. However, the existing thin film sensor preparation method mainly adopts the magnetron sputtering process for preparation, which is still difficult to prepare a high-temperature resistant insulating layer with good density and strong adhesion, and it is difficult to complement defects. It is easy to generate leakage current at high temperature, resulting in conduction between the thin film sensor and the substrate and introducing large measurement errors. It is also difficult to achieve the refined preparation of multiple functional film layers. Multiple functional films are prone to mutual interference, and it is difficult to ensure that the thin film sensor has high accuracy. At the same time, the existing preparation method also has the defects of complex process and difficult operation, which greatly limits the wide application of thin film sensors in blade process parameter monitoring. Therefore, it is of great significance to obtain a high-temperature resistant thin film sensor with good high temperature resistance, good stability, long service life, high measurement accuracy, and a simple process and convenient operation preparation method for the integration of temperature, strain and heat flow test functions, which is of great significance to promote the wide application of thin film sensors in blade process parameter monitoring. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a high-temperature resistant thin film sensor which has good high-temperature resistance, good stability, long service life and high measurement accuracy and integrates temperature, strain and heat flow testing functions. A preparation method of a high-temperature resistant thin film sensor which has simple process and convenient operation and integrates temperature, strain and heat flow testing functions is also provided.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions, comprising a substrate, wherein the surface of the substrate is provided with a high temperature glue layer, a Ta2O5 thin film layer and a SiO2 thin film layer in sequence from bottom to top; a multifunctional composite functional layer is provided on the SiO2 thin film layer; the multifunctional composite functional layer comprises a first thin film thermocouple for measuring temperature, a thermocouple stack for measuring heat flow and a strain sensitive grid for measuring strain; the multifunctional composite functional layer is also covered with a protective layer.

[0006] The above-mentioned high temperature resistant thin film sensor is further improved, wherein the material of the high temperature adhesive layer is Al2O3; the thickness of the high temperature adhesive layer is 3μm~5μm; the thickness of the Ta2O5 thin film layer is 1μm~1.5μm; the thickness of the SiO2 thin film layer is 1.5μm~2μm.

[0007] The above-mentioned high temperature resistant thin film sensor is further improved, wherein the first thin film thermocouple includes a first positive electrode thin film and a first negative electrode thin film, one end of the first positive electrode thin film is connected to one end of the first negative electrode thin film to form a working end; the material of the first positive electrode thin film is NiCr alloy; the thickness of the first positive electrode thin film is 600nm~800nm; the material of the first negative electrode thin film is NiSi alloy; the thickness of the first negative electrode thin film is 600nm~800nm.

[0008] The above-mentioned high temperature resistant thin film sensor is further improved, wherein the thermocouple stack includes at least two second thin film thermocouples connected in series, the second thin film thermocouple includes a second positive electrode film and a second negative electrode film, one end of the second positive electrode film is connected to one end of the second negative electrode film to form a working end; the material of the second positive electrode film is PtRh alloy; the thickness of the second positive electrode film is 1μm~5μm; the material of the second negative electrode film is Pt; the thickness of the second negative electrode film is 1μm~5μm.

[0009] The above-mentioned high temperature resistant thin film sensor is further improved in that the material of the strain sensitive grid is PdCr alloy; the thickness of the strain sensitive grid is 500nm.

[0010] The above-mentioned high temperature resistant thin film sensor is further improved, and the high temperature resistant thin film sensor also includes a first lead electrode, a second lead electrode, a third lead electrode, a fourth lead electrode, a fifth lead electrode, and a sixth lead electrode arranged on the substrate; the material of the first lead electrode, the second lead electrode, the third lead electrode, the fourth lead electrode, the fifth lead electrode, and the sixth lead electrode are all Pt; the thickness of the first lead electrode, the second lead electrode, the third lead electrode, the fourth lead electrode, the fifth lead electrode, and the sixth lead electrode are all 1μm to 1.5μm.

[0011] The above-mentioned high temperature resistant thin film sensor is further improved in that the external end of the first positive electrode thin film is connected to the first lead electrode; and the external end of the first negative electrode thin film is connected to the second lead electrode.

[0012] The above-mentioned high temperature resistant thin film sensor is further improved in that the external end of the second positive electrode thin film is connected to the third lead electrode; the external end of the second negative electrode thin film is connected to the fourth lead electrode.

[0013] The above-mentioned high temperature resistant thin film sensor is further improved in that two ends of the strain sensitive grid are respectively connected to the fifth lead electrode and the sixth lead electrode.

[0014] The above-mentioned high temperature resistant thin film sensor is further improved in that a thermal barrier layer is also provided on the thermocouple stack; the thermal barrier layer covers the middle part of the thermocouple; the material of the thermal barrier layer is Al2O3; the thickness of the thermal barrier layer is 3μm to 4μm.

[0015] The above-mentioned high temperature resistant thin film sensor is further improved in that the material of the protective layer is yttria-stabilized zirconium oxide and the thickness of the protective layer is 1 μm to 3 μm.

[0016] The above-mentioned high temperature resistant thin film sensor is further improved in that the substrate is an engine blade.

[0017] As a general technical concept, the present invention also provides a method for preparing a high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions, comprising the following steps:

[0018] S1, grinding and cleaning the substrate;

[0019] S2, coating a high temperature adhesive layer on the surface of the substrate;

[0020] S3, heat treating the high temperature adhesive layer;

[0021] S4, using a dual ion beam sputtering coating process to deposit a Ta2O5 thin film layer on the surface of the high temperature glue layer after heat treatment;

[0022] S5, heat treating the Ta2O5 thin film layer;

[0023] S6, depositing a SiO2 thin film layer on the surface of the heat-treated Ta2O5 thin film layer using a dual ion beam sputtering coating process;

[0024] S7, placing a flexible mask on the SiO2 thin film layer, and using a dual ion beam sputtering coating process to prepare a strain sensitive grid at a corresponding position on the SiO2 thin film layer; placing a stainless steel mask on the SiO2 thin film layer, and using a dual ion beam sputtering coating process to prepare a first thin film thermocouple at a corresponding position on the SiO2 thin film layer; placing a flexible mask on the SiO2 thin film layer, and using a dual ion beam sputtering coating process to prepare a thermocouple stack at a corresponding position on the SiO2 thin film layer;

[0025] S8, preparing a protective layer on the first thin film thermocouple, the thermocouple stack and the strain sensitive grid by using a dual ion beam sputtering coating process;

[0026] S9. Perform heat treatment on the protective layer to complete the preparation of the high temperature resistant thin film sensor.

[0027] The above preparation method is further improved, and step S7 also includes: placing a stainless steel mask on the thermocouple stack, and preparing a thermal barrier layer on the thermocouple stack using a dual ion beam sputtering coating process; during the preparation of the thermal barrier layer, the process parameters of the dual ion beam sputtering coating process are: voltage of 500V to 530V, and current of 50mA to 53mA.

[0028] The above-mentioned preparation method is further improved, and in step S8, before preparing the protective layer, it also includes: placing a flexible mask on the first thin film thermocouple, the thermocouple stack and the strain sensitive grid, and using a dual ion beam sputtering coating process to prepare a first lead electrode, a second lead electrode, a third lead electrode, a fourth lead electrode, a fifth lead electrode, and a sixth lead electrode on the SiO2 thin film layer; during the preparation of the first lead electrode, the second lead electrode, the third lead electrode, the fourth lead electrode, the fifth lead electrode, and the sixth lead electrode, the process parameters of the dual ion beam sputtering coating process are: using a Pt target material with a purity of 99.99% as the target material, a voltage of 500V~530V, and a current of 45mA~50mA.

[0029] The above preparation method is further improved, in step S1, the substrate is polished with 800# sandpaper for 20min to 30min; the cleaning is ultrasonic cleaning in acetone for 10min to 15min, ultrasonic cleaning in alcohol for 15min to 20min, and ultrasonic cleaning in deionized water for 15min to 20min in sequence; after the cleaning is completed, it is dried at 80°C to 100°C for 20min to 30min.

[0030] The above preparation method is further improved, in step S2, a high-temperature adhesive layer is coated on the surface of the substrate by using a glue spreader; after the coating is completed, it is air-dried in air for 1 hour to 1.5 hours.

[0031] The above preparation method is further improved. In step S3, the heat treatment is first heated to 80°C to 90°C for 25min to 45min, then heated to 215°C to 235°C for 20min to 40min, and finally heated to 330°C to 350°C for 30min to 50min.

[0032] The above preparation method is further improved. In step S4, the process parameters of the dual ion beam sputtering coating process are: using a Ta2O5 target material with a purity of 99.99% as the target material, and the background vacuum is less than 2.5×10 -4 Pa, voltage is 400V~450V, current is 40mA~50mA, and oxygen flow rate is 4sccm~6sccm.

[0033] The above preparation method is further improved, in step S5, the heat treatment is carried out in an oxygen atmosphere; the temperature of the heat treatment is 550°C to 650°C; and the time of the heat treatment is 4h to 6h.

[0034] The above preparation method is further improved. In step S6, the process parameters of the dual ion beam sputtering coating process are: using SiO2 target material with a purity of 99.99% as the target material, and the background vacuum is less than 3.0×10 -4 Pa, voltage is 460V~480V, current is 40mA~50mA, and oxygen flow rate is 6sccm~8sccm.

[0035] The above preparation method is further improved. In step S7, during the preparation of the strain sensitive gate, the process parameters of the dual ion beam sputtering coating process are: using 87% Pd-13% Cr target material with a purity of 99.99% as the target material, the voltage is 500V~550V, and the current is 45mA~55mA.

[0036] The above-mentioned preparation method is further improved. In step S7, during the preparation of the first thin film thermocouple, a 90% Ni-10% Cr target material with a purity of 99.99% is used as a target material to prepare the first positive electrode film, and a 97% Ni-3% Si target material with a purity of 99.99% is used as a target material to prepare the first negative electrode film; during the preparation of the first positive electrode film, the process parameters of the dual ion beam sputtering coating process are: voltage of 500V~550V, current of 45mA~55mA; during the preparation of the first negative electrode film, the process parameters of the dual ion beam sputtering coating process are: voltage of 500V, current of 40mA~50mA.

[0037] The above-mentioned preparation method is further improved. In step S7, during the preparation of the thermocouple stack, a Pt-10% Rh target material is used as a target material to prepare the second positive electrode film, and a Pt target material with a purity of 99.99% is used as a target material to prepare the second negative electrode film; during the preparation of the second positive electrode film, the process parameters of the dual ion beam sputtering coating process are: voltage of 500V~580V, current of 40mA~50mA; during the preparation of the second negative electrode film, the process parameters of the dual ion beam sputtering coating process are: voltage of 520V, current of 45mA~50mA.

[0038] The above preparation method is further improved. In step S8, the process parameters of the dual ion beam sputtering coating process are: using a YSZ target material with a purity of 99.99% as the target material, a voltage of 500V to 530V, and a current of 40mA to 55mA.

[0039] The above preparation method is further improved, in step S8, the temperature of the heat treatment is 1200° C.; the time of the heat treatment is 2 h to 5 h.

[0040] The above-mentioned preparation method is further improved, and the high-temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions includes a substrate, and the surface of the substrate is provided with a high-temperature glue layer, a Ta2O5 thin film layer and a SiO2 thin film layer from bottom to top; a multifunctional composite functional layer is provided on the SiO2 thin film layer; the multifunctional composite functional layer includes a first thin film thermocouple for measuring temperature, a thermocouple stack for measuring heat flow and a strain sensitive grid for measuring strain; the multifunctional composite functional layer is also covered with a protective layer.

[0041] The above preparation method is further improved, wherein the material of the high temperature adhesive layer is Al2O3; the thickness of the high temperature adhesive layer is 3μm to 5μm; the thickness of the Ta2O5 thin film layer is 1μm to 1.5μm; the thickness of the SiO2 thin film layer is 1.5μm to 2μm.

[0042] The above-mentioned preparation method is further improved, wherein the first thin film thermocouple includes a first positive electrode film and a first negative electrode film, one end of the first positive electrode film is connected to one end of the first negative electrode film to form a working end; the material of the first positive electrode film is NiCr alloy; the thickness of the first positive electrode film is 600nm~800nm; the material of the first negative electrode film is NiSi alloy; the thickness of the first negative electrode film is 600nm~800nm.

[0043] The above-mentioned preparation method is further improved, wherein the thermocouple stack includes at least two second thin film thermocouples connected in series, the second thin film thermocouple includes a second positive electrode film and a second negative electrode film, one end of the second positive electrode film is connected to one end of the second negative electrode film to form a working end; the material of the second positive electrode film is PtRh alloy; the thickness of the second positive electrode film is 1μm to 5μm; the material of the second negative electrode film is Pt; the thickness of the second negative electrode film is 1μm to 5μm.

[0044] The above preparation method is further improved in that the material of the strain sensitive gate is PdCr alloy; and the thickness of the strain sensitive gate pattern is 500nm.

[0045] The above-mentioned preparation method is further improved, and the high temperature resistant thin film sensor also includes a first lead electrode, a second lead electrode, a third lead electrode, a fourth lead electrode, a fifth lead electrode, and a sixth lead electrode arranged on the substrate; the material of the first lead electrode, the second lead electrode, the third lead electrode, the fourth lead electrode, the fifth lead electrode, and the sixth lead electrode are all Pt; the thickness of the first lead electrode, the second lead electrode, the third lead electrode, the fourth lead electrode, the fifth lead electrode, and the sixth lead electrode are all 1μm to 1.5μm.

[0046] The above preparation method is further improved in that the external end of the first positive electrode film is connected to the first lead electrode; the external end of the first negative electrode film is connected to the second lead electrode.

[0047] The above preparation method is further improved in that the external end of the second positive electrode film is connected to the third lead electrode; the external end of the second negative electrode film is connected to the fourth lead electrode.

[0048] The above-mentioned preparation method is further improved in that two ends of the strain sensitive gate are connected to the fifth lead electrode and the sixth lead electrode respectively.

[0049] The above preparation method is further improved in that a thermal barrier layer is also provided on the thermocouple stack; the thermal barrier layer covers the middle part of the thermocouple; the material of the thermal barrier layer is Al2O3; the thickness of the thermal barrier layer is 3μm to 4μm.

[0050] The above preparation method is further improved in that the material of the protective layer is yttria-stabilized zirconia; and the thickness of the protective layer is 1 μm to 3 μm.

[0051] The above-mentioned preparation method is further improved in that the substrate is an engine blade.

[0052] Compared with the prior art, the advantages of the present invention are:

[0053] (1) In view of the defects of existing thin film sensors such as poor high temperature resistance, poor stability, short service life and low measurement accuracy caused by poor compactness and adhesion of the insulating layer and easy cracking or falling off at high temperatures, the present invention creatively provides a high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions. A high temperature glue layer, a Ta2O5 thin film layer and a SiO2 thin film layer are arranged on the surface of the substrate from bottom to top. The high temperature resistant composite insulating layer formed thereby has the advantages of good compactness, good adhesion, good high temperature insulation and is not easy to crack or fall off under high temperature conditions. On this basis, a multifunctional composite functional layer is arranged on the high temperature resistant insulating layer, so that the multifunctional composite functional layer can be stably attached to the substrate, without Not only can the multifunctional composite functional layer be effectively prevented from falling off, cracking and other problems caused by stress concentration, but the multifunctional composite functional layer can also operate stably at higher operating temperatures and rotation speeds. The thin film sensor thus formed has the advantages of good high temperature resistance, good structural stability and long service life. At the same time, the high temperature resistant thin film sensor constructed by the present invention can simultaneously measure parameters such as temperature, strain and heat flow, and can measure a maximum temperature of 1500°C, and can be used normally for more than 100 hours at 1200°C. More importantly, by measuring real-time temperature data and combining the resistance temperature coefficient of the strain sensitive grid, the influence of temperature on the resistance value of the strain resistor can be eliminated, thereby compensating the strain resistor value and improving the strain measurement accuracy. Compared with conventional high-temperature resistant thin film sensors, the high-temperature resistant thin film sensor of the present invention integrates temperature, strain and heat flow testing functions, has more excellent high-temperature resistance and structural stability, longer service life, and higher measurement accuracy. It is a new type of thin film sensor that can be widely used and has excellent detection performance. It can be used to measure the working parameters (such as temperature, strain, heat flow, etc.) of turbine blades at high operating temperature and high speed. It has high use value and good application prospects.

[0054] (2) In view of the defects of existing thin film sensors, such as poor high temperature resistance, poor stability, short service life, and low measurement accuracy, caused by poor density and adhesion of the insulating layer and easy cracking or falling off at high temperatures, the present invention creatively provides a preparation method of a high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions. Considering that the substrate is generally a turbine blade, and the turbine blade is generally a nickel-based alloy with a maximum operating temperature of 1200°C, a high temperature glue (such as Al2O3) is first coated on the surface of the substrate and the high temperature glue is heat treated. By developing a heat treatment process for the high temperature glue layer, the high temperature glue layer is well adhered to the substrate material, that is, the high temperature The adhesive layer is stably attached to the surface of the substrate. At the same time, the Ta2O5 film layer and the SiO2 film layer formed on the surface of the high-temperature adhesive layer by ion beam sputtering have good adhesion to the high-temperature adhesive layer. The high-temperature resistant composite insulating layer thus formed has the advantages of good density, good adhesion, good high-temperature insulation and not easy to crack or fall off under high temperature conditions, thereby solving the problems of high-temperature adhesive adhesion and overall high-temperature shedding. Furthermore, considering the adhesion matching problem between the insulating film and the high-temperature adhesive, in order to prepare an insulating film layer with strong adhesion on the high-temperature adhesive layer, a dual ion beam sputtering process is selected to prepare the insulating film (Ta2O5 film, SiO2 film). The sputtering effect of the dual ion beam can not only Improving the morphology of the high-temperature adhesive layer surface is conducive to the stable adhesion of the insulating film on the surface of the high-temperature adhesive layer, and it can also prepare an insulating film with better density, which is conducive to improving the high-temperature resistance of the insulating film, so that it has stronger insulation strength at high temperatures. More importantly, the high-temperature adhesive and double ion beam sputtering are combined to prepare the high-temperature resistant insulating layer, which is to directly perform ion beam plating on the high-temperature adhesive. The high-temperature adhesive coating has low requirements on the surface roughness of the blade substrate, so there is no need to fully grind and polish the blade, avoiding the problem of blade grinding and polishing, saving time and cost, and increasing the success rate of insulating film preparation; on this basis, considering the adhesion of the multifunctional composite functional layer and the insulating film In order to solve the matching problem, the present invention adopts the dual ion beam sputtering method, which can not only prepare a multifunctional composite functional layer with good density, but also stably attach the multifunctional composite functional layer to the insulating film. At the same time, with the cooperation of the flexible mask and the hard mask, the line size of the multifunctional composite functional layer pattern can be effectively controlled, which can not only realize the refined preparation of the multifunctional composite functional layer, but also avoid the mutual interference between the sputtering of different functional layers, so as to improve the measurement accuracy of the sensor, thereby preparing a high-temperature resistant thin film sensor with good high-temperature resistance, high stability, long service life, and high measurement accuracy, which integrates temperature, strain and heat flow test functions. Compared with the conventional preparation method, the preparation method of the present invention has the advantages of simple process, convenient operation, low preparation cost, high yield rate, etc. It is suitable for large-scale preparation and conducive to industrial application.

[0055] (3) In the preparation method of the present invention, by optimizing the heat treatment process of the high-temperature adhesive layer, specifically, first heating the temperature to 80°C to 90°C for 250min to 45min, then heating the temperature to 215°C to 235°C for 20min to 40min, and finally heating the temperature to 330°C to 350°C for 30min to 50min, the high-temperature adhesive layer can be better attached to the substrate surface, thereby making the insulating film and the multifunctional composite functional layer more stably attached to the substrate surface, which is more conducive to improving the high temperature resistance and service life of the sensor.

[0056] (4) In the preparation method of the present invention, by optimizing the material system of the functional film layer (strain sensitive grid, first thin film thermocouple, thermocouple stack), for example, using 90% Ni-10% Cr target material and 97% Ni-3% Si target material with a purity of 99.99% as the target material for preparing the first thin film thermocouple, and using Pt-10% Rh target material and Pt target material with a purity of Pt as the target material for preparing the thermocouple stack, it can ensure that the sensor has better measurement effect and higher measurement accuracy. By optimizing the sputtering parameters (such as sputtering voltage and beam current) of the functional film layer (strain sensitive grid, first thin film thermocouple, thermocouple stack), the adhesion between the film layers is greatly increased, and the problem of the functional film layer falling off during the subsequent film layer preparation process is solved. By optimizing the heat treatment process parameters, it is more conducive to improving the compactness of each film layer, so as to ensure the quality and high-temperature stability of each film layer. For example, by optimizing the heat treatment temperature of the Ta2O5 thin film layer to 550℃~650℃ and the time to 4h~6h, it is more conducive to improving the compactness of the Ta2O5 thin film layer, so that the insulation performance of the insulating layer is better. For example, by optimizing the heat treatment temperature of the protective layer to 1200℃ and the time to 2h~5h, it is more conducive to improving the compactness of each film layer of the sensor, so that the sensor has better high-temperature stability. In order to solve the layout and miniaturization requirements of temperature, strain heat flow integrated high-temperature sensors, the sensor layout is finely designed in the present invention, and the lead electrodes are set at the root of the substrate and arranged in a row, which not only solves the problem of sensor lead interference testing but also increases the aesthetics and convenience of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0058] Figure 1 This is a schematic diagram of the cross-sectional structure of a high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions in Example 1 of the present invention.

[0059] Figure 2 This is a schematic diagram of the top view of the high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions in Example 1 of the present invention.

[0060] Figure 3 This is a process flow chart of preparing a high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions in Example 1 of the present invention.

[0061] Figures 4a to 4g This is a layout diagram of different masks in Example 1 of the present invention.

[0062] Legend:

[0063] 1. Substrate; 2. High-temperature adhesive layer; 3. Ta2O5 thin film layer; 4. SiO2 thin film layer; 5. Multifunctional composite functional layer; 511. First positive electrode thin film; 512. First negative electrode thin film; 521. Second positive electrode thin film; 522. Second negative electrode thin film; 53. Strain sensitive grid; 61. First lead electrode; 62. Second lead electrode; 63. Third lead electrode; 64. Fourth lead electrode; 65. Fifth lead electrode; 66. Sixth lead electrode; 8. Protective layer. DETAILED DESCRIPTION

[0064] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0065] Embodiment 1:

[0066] like Figure 1 and Figure 2 As shown, a high-temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions includes a substrate 1, on the surface of which a high-temperature adhesive layer 2, a Ta2O5 thin film layer 3 and a SiO2 thin film layer 4 are arranged in sequence from bottom to top, wherein a multifunctional composite functional layer 5 is arranged on the SiO2 thin film layer 4, and the multifunctional composite functional layer 5 includes a first thin film thermocouple for measuring temperature, a thermocouple stack for measuring heat flow and a strain sensitive grid 53 for measuring strain, and the multifunctional composite functional layer 5 is also covered with a protective layer 8.

[0067] In this embodiment, the material of the high temperature adhesive layer 2 is Al2O3, and the thickness is 3.5 μm; the thickness of the Ta2O5 thin film layer 3 is 1.5 μm; and the thickness of the SiO2 thin film layer 4 is 1.5 μm.

[0068] In this embodiment, the first thin film thermocouple includes a first positive electrode film 511 and a first negative electrode film 512, and one end of the first positive electrode film 511 is connected to one end of the first negative electrode film 512 to form a working end; the material of the first positive electrode film 511 is NiCr alloy with a thickness of 800nm; the material of the first negative electrode film 512 is NiSi alloy with a thickness of 800nm.

[0069] In this embodiment, the thermocouple stack includes at least two second thin film thermocouples connected in series, the second thin film thermocouple includes a second positive electrode film 521 and a second negative electrode film 522, one end of the second positive electrode film 521 is connected to one end of the second negative electrode film 522 to form a working end; the material of the second positive electrode film 521 is PtRh alloy, with a thickness of 2μm; the material of the second negative electrode film 522 is Pt, with a thickness of 2μm.

[0070] In this embodiment, the strain sensitive gate 53 is made of PdCr alloy and has a thickness of 500 nm.

[0071] In this embodiment, the high temperature resistant thin film sensor also includes a first lead electrode 61, a second lead electrode 62, a third lead electrode 63, a fourth lead electrode 64, a fifth lead electrode 65, and a sixth lead electrode 66 arranged on the root of the base (the end of the blade base close to the turbine bearing); the first lead electrode 61, the second lead electrode 62, the third lead electrode 63, the fourth lead electrode 64, the fifth lead electrode 65, and the sixth lead electrode 66 are all made of Pt, and their thickness is 1 μm.

[0072] In this embodiment, the external end of the first positive electrode film 511 is connected to the first lead electrode 61, and the external end of the first negative electrode film 512 is connected to the second lead electrode 62. The first lead electrode 61 and the second lead electrode 62 are respectively connected to the data collector through lead wires.

[0073] In this embodiment, the external end of the second positive electrode film 521 is connected to the third lead electrode 63, and the external end of the second negative electrode film 522 is connected to the fourth lead electrode 64. The third lead electrode 63 and the fourth lead electrode 64 are respectively connected to the data collector through lead wires.

[0074] In this embodiment, two ends of the strain sensitive grid 53 are respectively connected to the fifth lead electrode 65 and the sixth lead electrode 66. The fifth lead electrode 65 and the sixth lead electrode 66 are respectively connected to the data acquisition device through lead wires.

[0075] In this embodiment, a thermal barrier layer is further provided on the thermocouple stack, and the thermal barrier layer covers the middle part of the thermocouple stack, wherein the material of the thermal barrier layer is Al2O3 and the thickness is 3.5 μm.

[0076] In this embodiment, the material of the protective layer 8 is yttria-stabilized zirconia, and the thickness is 3 μm.

[0077] In this embodiment, the substrate 1 is an engine blade.

[0078] A method for preparing a high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions in the above embodiment, the schematic diagram of the preparation process is as follows Figure 3As shown, the following steps are included:

[0079] (1) Surface grinding: Use 800# sandpaper to grind the surface of the engine blade for 20 minutes.

[0080] (2) Cleaning: The polished engine blades were ultrasonically cleaned in acetone for 15 min, in alcohol for 15 min, and in deionized water for 15 min, and then dried at 100°C for 20 min.

[0081] (3) Applying high-temperature glue: Place the engine blade in a glue-spreading fixture, and use a glue-spreading machine to evenly apply a layer of high-temperature glue whose main material is Al2O3 on the polished surface of the engine blade, with a thickness controlled at 3.5 μm.

[0082] (4) Heat treatment with high temperature glue: The engine blades coated with high temperature glue are placed in air to dry for 1 hour, and then placed in a drying oven for heat treatment. The heat treatment process is to first heat the temperature to 85°C for 30 minutes, then heat the temperature to 215°C for 30 minutes, and finally heat the temperature to 335°C for 30 minutes.

[0083] (5) Preparation of Ta2O5 thin film: Ta2O5 thin film was prepared on the high temperature glue layer after heat treatment by dual ion beam sputtering coating process, wherein the target material used was Ta2O5 target material with a purity of 99.99%, and the sputtering background vacuum was less than 2.5*10 -4 Pa, the sputtering voltage is 450 V, the sputtering current is 45 mA, oxygen is supplemented during the sputtering process, the oxygen flow rate is 4 sccm, and the sputtering thickness is 1.5 μm.

[0084] (6) Heat treatment of Ta2O5 film: The engine blade coated with Ta2O5 film is placed in a high-temperature tube furnace for oxidation heat treatment, wherein the heat treatment temperature is 600°C, the heat treatment time is 4 h, and oxygen is passed through the heat treatment process with a flow rate of 4 sccm.

[0085] (7) Preparation of SiO2 thin film: SiO2 thin film was prepared on the oxidized Ta2O5 thin film by dual ion beam coating method. The target material was SiO2 target with a purity of 99.99%. The sputtering background vacuum was less than 3.0*10 -4 The sputtering voltage is 460 V, the sputtering current is 44 mA, oxygen is supplemented during the sputtering process, the oxygen flow rate is 6 sccm, and the sputtering thickness is 1.5 μm.

[0086] (8) Preparation of PdCr strain sensitive gate: Figure 4aAs shown, a flexible mask 71 is placed on the SiO2 film layer, and a PdCr strain sensitive gate is prepared at the corresponding position of the SiO2 film by a dual ion beam sputtering method. The target material uses a 87% Pd-13% Cr target material with a purity of 99.99%, a sputtering voltage of 550 V, a sputtering current of 48 mA, and a sputtering thickness of 500 nm.

[0087] (9) Preparation of thin film thermocouples: Figure 4b , 4c As shown, a stainless steel mask is placed on the SiO2 film layer, and a K-type thin film thermocouple is prepared at the corresponding position of the SiO2 film by a dual ion beam sputtering method. First, a NiCr positive electrode thin film is prepared using a stainless steel mask 72, and a 90% Ni-10% Cr target with a purity of 99.99% is used as the target material, the sputtering voltage is 550V, the sputtering current is 48mA, and the sputtering thickness is 800nm. Then, a NiSi negative electrode thin film is prepared using a stainless steel mask 73, and a 97% Ni-3% Si target with a purity of 99.99% is used as the target material, the sputtering voltage is 500V, the sputtering current is 45mA, and the sputtering thickness is 800nm.

[0088] (10) Preparation of thermocouple stack: Figure 4d , 4e As shown, a flexible mask is placed on the SiO2 film layer, and a thermocouple stack is prepared at the corresponding position of the SiO2 film by dual ion beam sputtering. First, a positive electrode Pt-10% Rh film is prepared using a flexible mask 74, and a Pt-10% Rh target with a purity of 99.99% is used as the target material, the sputtering voltage is 500V, the sputtering current is 50mA, and the sputtering thickness is 2μm. Then, a negative electrode Pt film is prepared using a flexible mask 75, and a Pt target with a purity of 99.99% is used as the target material, the sputtering voltage is 520V, the sputtering current is 50mA, and the sputtering thickness is 2μm.

[0089] (11) Preparation of thermal barrier layer of thermocouple stack: Figure 4f As shown, a stainless steel mask 76 is placed on the thermocouple stack, and an Al2O3 thermal barrier layer is prepared at the corresponding position of the thermocouple stack by dual ion beam sputtering. The thermal barrier layer covers the middle half of the thermocouple stack. The sputtering voltage is 450V, the sputtering current is 50mA, and the sputtering thickness is 3.5μm.

[0090] (12) Preparation of Pt electrode: Figure 4gAs shown, a flexible mask 77 is placed on the first thin film thermocouple, the thermocouple stack and the strain sensitive grid, and a dual ion beam sputtering method is used to prepare Pt electrodes (including a first lead electrode, a second lead electrode, a third lead electrode, a fourth lead electrode, a fifth lead electrode and a sixth lead electrode) at the electrode positions of the PrCr strain sensitive grid, the thin film thermocouple and the thermocouple stack. The target material used is a Pt target material with a purity of 99.99%, the sputtering voltage is 520 V, the sputtering current is 50 mA, and the sputtering thickness is 1 μm.

[0091] (13) Preparation of YSZ protective layer: A YSZ protective layer was prepared on all sensitive layers except the electrode by dual ion beam sputtering. The target material used was a YSZ target with a purity of 99.99%. The sputtering voltage was 500 V, the sputtering current was 55 mA, and the sputtering thickness was 3 μm.

[0092] (14) Heat treatment: The sample is placed in an air environment at 1200°C for high temperature annealing for 2 h. After cooling to room temperature, the sample is taken out to obtain an engine blade high temperature resistant thin film sensor that integrates temperature, strain and heat flow testing functions.

[0093] After testing, the engine blade high temperature resistant thin film sensor integrated with temperature, strain and heat flow testing functions prepared by the present invention can work normally for more than 100 hours under high temperature conditions of 1200°C, while the normal working time of the existing conventional high temperature resistant thin film sensor (the high temperature resistant insulating layer used in the sensor is composed of a high temperature oxide layer, an Al2O3 thin film layer, a Ta2O5 thin film layer and a Si3N4 thin film layer) is generally 50 hours, which shows that the high temperature resistant thin film sensor of the present invention has more excellent high temperature resistance and stability, and a longer service life; at the same time, the engine blade high temperature resistant thin film sensor integrated with temperature, strain and heat flow testing functions prepared by the present invention, when used to simultaneously measure temperature, strain and heat flow, has a temperature measurement range of 0 to 1500°C, a strain test range of 0 to 6000 microstrain, a heat flow test range of 0 to 2 MW, and a temperature measurement accuracy of 1.5% FS, a strain measurement accuracy of 5% FS, and a heat flow test accuracy of 8% FS. It can be seen that the high-temperature resistant thin film sensor of the present invention, which integrates temperature, strain and heat flow testing functions, has the advantages of good temperature resistance, high performance, good stability, long service life, high measurement accuracy, etc. It is a new type of thin film sensor that can be widely used and has excellent detection performance. It can be used to measure the working parameters (such as temperature, strain, heat flow, etc.) of turbine blades at high operating temperature and high speed. It has high use value and good application prospects.

[0094] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions, characterized in that: It comprises a substrate, on the surface of which a high temperature glue layer, a Ta2O5 thin film layer and a SiO2 thin film layer are arranged in sequence from bottom to top; a multifunctional composite functional layer is arranged on the SiO2 thin film layer; the multifunctional composite functional layer comprises a first thin film thermocouple for measuring temperature, a thermocouple stack for measuring heat flow and a strain sensitive grid for measuring strain; the multifunctional composite functional layer is also covered with a protective layer; the first thin film thermocouple comprises a first positive electrode thin film and a first negative electrode thin film, one end of the first positive electrode thin film is connected to one end of the first negative electrode thin film to form a working end; the material of the first positive electrode thin film is NiCr alloy; the thickness of the first positive electrode thin film is 600nm-800nm; the material of the first negative electrode thin film is NiSi alloy; the thickness of the first negative electrode thin film is 600nm-800nm; the thermocouple stack comprises at least two second thin film thermocouples connected in series, the second thin film thermocouple comprises a second positive electrode thin film and a second negative electrode film, one end of the second positive electrode film is connected to one end of the second negative electrode film to form a working end; the material of the second positive electrode film is PtRh alloy; the thickness of the second positive electrode film is 1μm~5μm; the material of the second negative electrode film is Pt; the thickness of the second negative electrode film is 1μm~5μm; the material of the strain sensitive grid is PdCr alloy; the thickness of the strain sensitive grid is 500nm; the high temperature resistant thin film sensor also includes a first lead electrode, a second lead electrode, a third lead electrode, a fourth lead electrode, a fifth lead electrode, and a sixth lead electrode arranged on the substrate; the material of the first lead electrode, the second lead electrode, the third lead electrode, the fourth lead electrode, the fifth lead electrode, and the sixth lead electrode are all Pt; the thickness of the first lead electrode, the second lead electrode, the third lead electrode, the fourth lead electrode, the fifth lead electrode, and the sixth lead electrode are all 1μm~1.5μm.

2. The high temperature resistant thin film sensor according to claim 1, characterized in that: The material of the high temperature adhesive layer is Al2O3; the thickness of the high temperature adhesive layer is 3μm to 5μm; the thickness of the Ta2O5 thin film layer is 1μm to 1.5μm; the thickness of the SiO2 thin film layer is 1.5μm to 2μm.

3. The high temperature resistant thin film sensor according to claim 2, characterized in that: The external end of the first positive electrode film is connected to the first lead electrode; the external end of the first negative electrode film is connected to the second lead electrode; The external end of the second positive electrode film is connected to the third lead electrode; the external end of the second negative electrode film is connected to the fourth lead electrode; Two ends of the strain sensitive grid are connected to the fifth lead electrode and the sixth lead electrode respectively.

4. The high temperature resistant thin film sensor according to any one of claims 1 to 3, characterized in that: A thermal barrier layer is also provided on the thermocouple stack; the thermal barrier layer covers the middle part of the thermocouple; the material of the thermal barrier layer is Al2O3; the thickness of the thermal barrier layer is 3μm to 4μm; The material of the protective layer is yttria-stabilized zirconium oxide; the thickness of the protective layer is 1 μm to 3 μm; The substrate is an engine blade.

5. A method for preparing a high temperature resistant thin film sensor integrating temperature, strain and heat flow testing functions as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1, grinding and cleaning the substrate; S2, coating a high temperature adhesive layer on the surface of the substrate; S3, heat treating the high temperature adhesive layer; S4, using a dual ion beam sputtering coating process to deposit a Ta2O5 thin film layer on the surface of the high temperature glue layer after heat treatment; S5, heat treating the Ta2O5 thin film layer; S6, depositing a SiO2 thin film layer on the surface of the heat-treated Ta2O5 thin film layer using a dual ion beam sputtering coating process; S7, placing a flexible mask on the SiO2 thin film layer, and using a dual ion beam sputtering coating process to prepare a strain sensitive grid at a corresponding position on the SiO2 thin film layer; placing a stainless steel mask on the SiO2 thin film layer, and using a dual ion beam sputtering coating process to prepare a first thin film thermocouple at a corresponding position on the SiO2 thin film layer; The flexible mask is placed on the SiO2 thin film layer, and a thermocouple stack is prepared at a corresponding position on the SiO2 thin film layer by using a dual ion beam sputtering coating process; S8, preparing a protective layer on the first thin film thermocouple, the thermocouple stack and the strain sensitive grid by using a dual ion beam sputtering coating process; S9, heat-treating the protective layer to complete the preparation of the high temperature resistant thin film sensor; Step S7 further includes: placing a stainless steel mask on the thermocouple stack, and preparing a thermal barrier layer on the thermocouple stack by a dual ion beam sputtering coating process; during the preparation of the thermal barrier layer, the process parameters of the dual ion beam sputtering coating process are: a voltage of 500V to 530V, and a current of 50mA to 53mA; In step S8, before preparing the protective layer, it also includes: placing a flexible mask on the first thin film thermocouple, the thermocouple stack and the strain sensitive grid, and using a dual ion beam sputtering coating process to prepare a first lead electrode, a second lead electrode, a third lead electrode, a fourth lead electrode, a fifth lead electrode, and a sixth lead electrode on the SiO2 thin film layer; during the preparation of the first lead electrode, the second lead electrode, the third lead electrode, the fourth lead electrode, the fifth lead electrode, and the sixth lead electrode, the process parameters of the dual ion beam sputtering coating process are: using a Pt target material with a purity of 99.99% as a target material, a voltage of 500V to 530V, and a current of 45mA to 50mA.

6. The preparation method according to claim 5, characterized in that In step S1, the substrate is polished with 800# sandpaper for 20 min to 30 min; the cleaning is ultrasonic cleaning in acetone for 10 min to 15 min, ultrasonic cleaning in alcohol for 15 min to 20 min, and ultrasonic cleaning in deionized water for 15 min to 20 min in sequence; after the cleaning is completed, the substrate is dried at 80°C to 100°C for 20 min to 30 min; In step S2, a high-temperature adhesive layer is coated on the surface of the substrate by using a glue spreader; after the coating is completed, the substrate is air-dried in air for 1 hour to 1.5 hours; In step S3, the heat treatment is firstly heated to 80°C to 90°C for 25 min to 45 min, then heated to 215°C to 235°C for 20 min to 40 min, and finally heated to 330°C to 350°C for 30 min to 50 min; In step S4, the process parameters of the dual ion beam sputtering coating process are: using a Ta2O5 target with a purity of 99.99% as the target material, and the background vacuum is less than 2.5×10 -4 Pa, voltage is 400V~450V, current is 40mA~50mA, oxygen flow rate is 4sccm~6sccm; In step S5, the heat treatment is performed in an oxygen atmosphere; the temperature of the heat treatment is 550° C. to 650° C.; the time of the heat treatment is 4 h to 6 h; In step S6, the process parameters of the dual ion beam sputtering coating process are: using SiO2 target material with a purity of 99.99% as the target material, and the background vacuum is less than 3.0×10 -4 Pa, voltage is 460V~480V, current is 40mA~50mA, oxygen flow rate is 6sccm~8sccm; In step S7, during the preparation of the strain sensitive grid, the process parameters of the dual ion beam sputtering coating process are: using 87% Pd-13% Cr target material with a purity of 99.99% as the target material, the voltage is 500V~550V, and the current is 45mA~55mA; during the preparation of the first thin film thermocouple, using 90% Ni-10% Cr target material with a purity of 99.99% as the target material to prepare the first positive electrode thin film, and using 97% Ni-3% Si target material with a purity of 99.99% as the target material to prepare the first negative electrode thin film; during the preparation of the first positive electrode thin film, the process parameters of the dual ion beam sputtering coating process are: voltage is 500V~550V, current is 45mA~55 mA; in the preparation process of the first negative electrode film, the process parameters of the dual ion beam sputtering coating process are: voltage of 500V, current of 40mA~50mA; in the preparation process of the thermocouple stack, a Pt-10%Rh target material with a purity of 10% was used as a target material to prepare the second positive electrode film, and a Pt target material with a purity of 99.99% was used as a target material to prepare the second negative electrode film; in the preparation process of the second positive electrode film, the process parameters of the dual ion beam sputtering coating process are: voltage of 500V~580V, current of 40mA~50mA; in the preparation process of the second negative electrode film, the process parameters of the dual ion beam sputtering coating process are: voltage of 520V, current of 45mA~50mA; In step S8, the process parameters of the dual ion beam sputtering coating process are: using a YSZ target material with a purity of 99.99% as the target material, a voltage of 500V to 530V, and a current of 40mA to 55mA; In step S9, the temperature of the heat treatment is 1200° C.; the time of the heat treatment is 2 h to 5 h.

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