Enhanced temperature sensing performance of T-type TFTCs with SiC encapsulation layer from liquid nitrogen to 900 ℃

In iron and steel metallurgy, accurate temperature monitoring of the crystallizer is essential for safe production. However, extreme conditions-including high temperatures, pressure, friction, and the limitations of traditional detection methods-hinder precise measurements. To address these challenges, we developed T-type thin-film thermocouples (TFTCs) with a silicon carbide (SiC) protective layer, achieving stable, high accuracy across a wide temperature range. The sensor operates effectively in both liquid nitrogen and high-temperature, with a maximum error of −0.9 °C in calibration experiments conducted between −80 °C and 900 °C. Long-term stability tests demonstrate reliable operation for 24 h at 700 °C and for up to one month at 300 °C and 600 °C, with maximum errors of 3.9 °C, −1.8 °C, and −4.3 °C, respectively. This sensor exhibits robust capabilities for stable and long-term temperature measurement. Its precision and stability enable simultaneous measurement of both low and high temperatures, offering significant potential for continuous monitoring of crystallizer copper plate temperatures in iron and steel production.