Thin-Film Thermocouple With Microcrystalline Glass Encapsulation for High-Temperature Applications

Troubleshooting of the hot-end components of aeroengines at high temperatures is critical in the aerospace field. However, current thin-film temperature sensors often cannot provide both high accuracy and high-temperature resistance, which limits the application of these sensors to hot-end components of aeroengines. Herein, an ITO/In2O3 thin-film thermocouple (TFTC) encapsulated in microcrystalline glass is developed through a facile and high-efficient tape mask process and magnetron technology. The protection mechanism of the microcrystalline glass on the ITO and In2O3 films was elucidated and used to achieve continuous operation at $1100~^{\circ }$ C for 130 h with a low drift rate (DR) ( $0.374~^{\circ }$ C/h). The TFTC exhibited excellent repeatability and high accuracy (above 0.5% FS), which was six times the accuracy of the unencapsulated TFTC. The TFTC with a protective layer of microcrystalline glass was prepared on an aeroengine guide vane to monitor radiative heat transfer at $1040~^{\circ }$ C. The application of TFTC with microcrystalline glass encapsulation on guide vanes paves the way for the development of health monitoring of aeroengine hot-end components.