Europium-doped Yttria-stabilized Zirconia for High-temperature Phosphor Thermometry

In this paper a study of the temperature-dependent luminescence properties of europium-doped yttria-stabilized zirconia (YSZ: Eu) powder are presented with a view to evaluating the potential of this material and lanthanide-doped YSZ generally for temperature measurement in the thermal barrier coating systems used in gas turbines. The time constant of the exponential emission decay occurring after ultraviolet excitation with a pulsed neodymium-doped yttrium aluminium garnet (YAG: Nd) laser was shown to be temperature dependent with a dynamic range from 26 to 800°C. Temperature dependence was observed for two distinct emission lines at 591 and 607 nm and the precision with which temperatures can be measured was estimated to be ±0.05 °C at the elevated temperature. The results demonstrate that YSZ: Eu can be considered as a thermographic phosphor and employed for temperature or heat flux measurements on surfaces in gas turbines or for monitoring purposes during coating production where the temperature is an important controlling parameter. Possible improvements in the measurement system to enhance its performance, the optimization of the YSZ: Eu formulation and the use of other lanthanides dopants are proposed for future work.