Polymer-derived ceramic thin-film thermocouples for high temperature measurements

Thin-film thermocouples are used as temperature detection components in aircraft engines. However, the preparation of traditional thin-film thermocouples is complex, and their high-temperature stability performance attributes are poor. In this study, polymer-derived ceramic (PDC) technology is introduced to prepare polymer-derived ceramic thin-film thermocouples. Due to the superior high-temperature and adhesion performance characteristics of polymer-derived ceramics and the protective effects of the products of polymer precursors on the thin films, the performance attributes of thin-film thermocouples are greatly improved. After simplifying the preparation process and outputting a large thermoelectric potential, the polymer-derived ceramic thin-film thermocouple exhibits good repeatability, stability, and thermoelectric potential output consistency. At 1200 °C, the peak output is 203 mV, and the average Seebeck coefficient is approximately 182 μV/°C. The temperature measurement error is 0.316%. In the 8-h drift test, the coefficient first increases at 1.26 °C/h and then steadily decreases at −0.63 °C/h. This polymer-derived ceramic thin-film thermocouple has excellent performance and can be applied to the in situ monitoring of thermal components in high-temperature and harsh environments, such as engines.