1000 H STABILITY TEST OF THE AU PD THERMOCOUPLE AT 1000-DEGREES-C/

A newly developed Au/Pd thermocouple has shown very high reproducibili ty and good immersion characteristics. A stability test of the Au/Pd t hermocouple has been conducted for 1000 h at 1000 degrees C in air to assess its suitability for practical application. Two thermocouples fr om two manufacturers were fabricated and their emf values were checked in a silver freezing-point cell before and after the soaking at 1000 OC. It was found that the high-temperature stability of the Au/Pd ther mocouple is within +/-30 mK (2 sigma) throughout the test time. This r esult implies that the Au/Pd thermocouple possesses characteristics wh ich may make it suitable for use as a secondary high-temperature therm ometer in industry.