Integration of ITO-In₂O₃ Thin-Film Thermocouples on NiCoCrAlY Coating for In Situ Aeroengine Alloy Blades Temperature Monitoring

Monitoring the internal temperature of aeroengines is crucial for ensuring their performance and safety, as excessive temperatures can lead to engine failure. However, traditional temperature measurement methods exhibit limitations, such as interference with the flow field and an inability to conduct in situ temperature measurements while providing real-time feedback. In this study, a multinode thermocouple sensor was developed for the in situ temperature detection of the surface of aeroengine blades. The thin-film architecture of the sensor facilitates in situ preparation without disrupting the surface smoothness of the tested component. To achieve this, a multilayer film structure was created on the blade surface using microelectromechanical system (MEMS) technology, employing NiCoCrAlY alloy as the transition layer and Al₂O₃ as the insulating layer material. ITO-In₂O₃ thin-film thermocouples (TFTCs) were subsequently deposited directly onto the surface of the aeroengine turbine blades using magnetron sputtering technology (MST). Performance tests indicate that TFTC sensors annealed at 900 ◦C can achieve an average Seebeck coefficient of 64.30 µV/◦C, with a repeatability of 96.9% at 850 ◦C and a laser dynamic response time of 11.69 µs. Under high-temperature airflow conditions, the sensor maintained excellent thermoelectric output performance and temperature measurement capability. The proposed sensor, after further optimization, may be suitable for in situ monitoring of temperatures within aircraft engine turbines. This capability would be valuable for performance assessment, failure detection, and the optimization of turbine blades.