High Spatial Resolution High-Temperature Thin-Film Temperature Sensor With HfO₂ Protective Layer

Accurate measurement of temperature fields with high spatial resolution in extreme environments is critically important for applications including aerospace, steel smelting, and blast damage analysis. However, current temperature measurement methods for ultra-high temperature components, whether on surfaces or internal structures, are predominantly limited to single-point measurements with low spatial resolution, hindering accurate representation of localized temperature fields in components or structures. In this study, we propose a high spatial resolution thin-film thermocouple array featuring shared electrodes. The sensitive electrodes, composed of ITO/In2O3, and a protective HfO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> layer are fabricated through a magnetron sputtering process. This design facilitates accurate multi-point temperature measurements on surfaces or within structures under extreme conditions, up to 1100 °C, enabling precise capture of temperature gradients in temperature fields. The thin-film thermocouple array with an HfO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> protective layer exhibits outstanding high-temperature stability, with a maximum drift rate of 0.27 °C/h at 1100 °C, and high accuracy, achieving a full-scale measurement error of ±1.6% across the range of 50 °C to 1100 °C. This work presents a feasible approach for precise temperature field measurement in extreme environments.