Fabrication and calibration of Pt-10%Rh/Pt thin film thermocouples

Platinum-10% rhodium vs. platinum thin film thermocouples with multi-layer structure were prepared on the nickel based superalloy substrates. The samples were calibrated in a thermocouple calibrating furnace in temperature range from 200 °C to 950 °C. The influences of anneal on the Seebeck coefficient and the relative sensitivity coefficient were investigated in detail. The results show that the Seebeck coefficient of the samples annealed in air is degenerated from 7.7 μV/°C down to 7.32 μV/°C and the sensitive coefficient is degenerated from 0.742 to 0.647 in average. However, the samples annealed in vacuum is improved from 7.7 μV/°C to 8.28 μV/°C and the sensitive coefficient is improved from 0.742 to 0.911 in average. The error was limited to 11 °C from 200 °C to 1000 °C. The loss efficacy time of all the samples is less than 20 h in our test condition.