Metrological Comparison and Uncertainty Analysis of Standard Platinum-Rhodium 30-Platinum-Rhodium 6 Thermocouples

Thermocouple sensors based on Seebeck effect are widely used in industrial fields such as petrochemical, metallurgical, and aerospace due to their simple structure, high reliability and wide temperature range. To evaluate the technical consistency of national metrology institutions in high-temperature measurement and transfer capabilities, the National Administration of Market Regulation organized the “Metrological Comparison Project for Standard Platinum Rhodium 30-Platinum Rhodium 6 Thermocouple Verification Devices.” The pilot laboratory is the National Institute of Metrology. Five characteristic temperature points (1100 °C, 1200 °C, 1300 °C, 1400 °C, 1500 °C) were set in the 1100 °C–1500 °C temperature zone by the transfer standard method, and The normalized deviation (En value) was employed to quantify the thermoelectric voltage measurement deviations of participating laboratories. Experimental data demonstrated that the absolute En values for all laboratories were below the critical threshold of 1. Further combined with measurement uncertainty analysis, the results verified the metrological transfer capabilities of these institutions in high-temperature ranges, as well as the traceability assurance of China’s high-temperature metrology system, providing technical support for international equivalence and mutual recognition.