Research On Preparation And Performance Of High Precision Flexible Thin Film Temperature Sensor With Graphical Design

Hot-end components such as compressor blades and bearings are core components in the aviation field.Instantaneous changes in temperature seriously affect the working life of hot-end components.Meanwhile,as the surface structure of hot-end components become complex,it puts forward higher requirements for temperature measurement accuracy.So,it is critical to monitor the temperature information of hot-end components rapidly and accurately in real-time for their reliability and safety.Based on the measurement of temperature information of hot-end components with heterogeneous surface structures and combined with thin film fabrication technology and finite element simulation,the design and fabrication of flexible and high-precision platinum（Pt）thin film thermal resistance were investigated in this thesis.Then the performance of static and dynamic properties of thin film thermal resistance was further studied.Firstly,based on finite element simulation,the effects of applying the load in different directions and the different patterns of the functional layer on the change of resistance of the sensor were investigated,and the functional layer structure of the sensor was further optimized.The simulation results show that the resistance change of the sensor is significantly affected by applying the load along the Z axis（vertical direction）,followed by applying the load along the X axis（horizontal transverse direction）,and applying the load along the Y axis（horizontal longitudinal direction）is the least.However,when applying the load in the same direction,the absolute value of the relative change in resistance of the sensor with fractal pattern is smaller than that of the sensor with serpentine pattern,indicating that the fractal pattern can enhance the flexibility and stretchability of the sensor and reduce the interference of stress on the sensor.Secondly,thin film thermal resistance with multilayer structure was prepared and the performance of the insulating layer was studied.The graphical design of functional layer was fulfilled by using photolithography technology and the thin film was deposited by magnetron sputtering.The high temperature performance test results of the insulation layer show that compared with the Al₂O₃ insulation layer and the Al ON+Al₂O₃ composite insulation layer,the resistance of the YSZ/Al₂O₃ composite insulation layer is 2 MΩat800℃,demonstrating excellent insulation performance.It can be seen from the SEM cross-sectional images that the sensors have multilayered film structure,and the structure of the YSZ/Al₂O₃ composite insulation layer is dense and free of pores and cracks.Finally,the performance of static and dynamic of the sensors was studied.Multiple cycle calibrations results show that the sensors exhibit excellent repeatability and consistency.The excellent insulation performance of the YSZ/Al₂O₃ composite insulating layer improves the measurement accuracy of the sensor.Its measurement uncertainty is±1.33℃,which is superior to the sensors with the Al₂O₃ and Al ON+Al₂O₃ composite insulating layers.At the same time,the thermal hysteresis and measurement uncertainty of the sensor with Al₂O₃ protective layer are 0.64%and±1.23℃,which are significantly superior to the standard Pt100 temperature sensor and the sensor without protective layer.So,the Al₂O₃ protective layer can improve the stability and measurement accuracy of the sensor.The response time of the sensors was measured by pulsed laser.The results show that the sensor with YSZ/Al₂O₃ composite insulating layer has faster response,with a response time of 97.30μs.However,the protective layer can affect heat transfer,which can slow down the response speed of the sensor.The bending test results show that the flexibility and stretchability of the sensor with fractal pattern were significantly improved.The influence of the substrate deformation and vibration on the performance of the sensor could be mitigated.The pattern of functional layer has little impact on the measurement uncertainty and response time of the sensors.The sensor installed on the metal substrate by welding process exhibits excellent stability,tracking and erosion resistance characteristics in wind tunnel tests.