Remarkable thermal stability of zirconium-yttrium oxide thin film thermistors for ultra-high temperature measurement up to 1500 ℃

The pursuit of high-temperature resistance, long-term reliability and stability simultaneously for thermosensitive thin film materials is longstanding. However, most precious metal or ceramic thin films face oxidation failure and instability in extremely high-temperature environments, making it difficult to meet the demands of practical applications. Herein, zirconium-yttrium oxide (ZYO) is initially proposed to be used as the thermosensitive thin film material for ultra-high temperature measurement. ZYO thin films with high quality were produced via magnetron sputtering. Furthermore, the recrystallization refinement process during high-temperature annealing fills the voids in the film, resulting in a uniform and dense microstructure. Such configuration underpins the remarkable thermal stability of the ZYO thin film thermistor, which exhibits a resistance drift rate of only 0.67 %/h at 1200 °C and remain the function when exposure at 1550 °C. Following the Steinhart-Hart equation, it also achieves real-time temperature sensing across 800 ℃ to 1500 ℃ with excellent repeatability. Notably, through the cyclic thermal shocks of 200 ℃/s heating to 1500 ℃, the thin film thermistor illustrates the stable microstructure and electrical properties. This attractive material with excellent thermosensitive performance has tremendous application potential in extreme environments.