Development of Low-Drift Nickel-Based Thermocouples for High-Temperature Applications

Recent progress on the new nickel-based thermocouples for high-temperature applications developed at the Department of Materials Science and Metallurgy in the University of Cambridge is described in this paper. Isothermal drift at temperatures above 1000 °C as a function of the thermocouple diameter has been studied for both conventional nickel-based thermocouples and the new nickel-based thermocouple. The new nickel-based thermocouple experiences a much reduced drift compared to conventional sensors. Tests in thermal cyclic conditions have been undertaken on conventional and new nickel-based thermocouples, showing a clear improvement for the new sensors at temperatures both higher and lower than 1000 °C. The improvements achievable with the new nickel-based thermocouple in both isothermal and thermal cycling conditions suggest that the new sensor can be used at high temperatures, where current conventional sensors are not reliable, as well as at temperatures lower than 1000 °C with improved performance compared to the conventional sensors.