Enhanced La0.8Sr0.2CrO3/Pt thin film thermocouple with Al2O3 coating layer for high temperature sensing

Abstract Thin film thermocouples (TFTCs) as a kind of passive sensor are used to measure in-situ high temperature and integrated surface devices. In this work, La0.8Sr0.2CrO3/Pt TFTCs were successfully fabricated by RF sputtering method. When the TFTCs were tested below 900 °C for multi-cycles, they showed an excellent stability and reproducibility. By comparing with the thermal responses of uncoated and coated with Al2O3 protection layer, the coated TFTC had a higher measurement temperature than uncoated TFTC, and good durability. The failure of TFTCs was mainly attributed to the volatilization of Pt and 0.2LSCO thin films at high temperature, while 0.2LSCO had a better thermal stability than Pt. The La0.8Sr0.2CrO3/Pt TFTC coated with Al2O3 protection layer may provide a new candidate thermal sensor for high temperature sensing in air.