Phosphor thermometry instrumentation for synchronized acquisition of luminescence lifetime decay and intensity on thermal barrier coatings

Thermal barrier coatings (TBCs) are used to protect turbine components from extreme environments and to allow for the turbine system to operate at temperatures beyond the melting point of the underlying superalloy blade. Existing in situ temperature measurement methods for high temperature evaluation have inherent uncertainties that impose important safety margins. Improving the accuracy of temperature measurements on the materials in operating conditions is key for more reliable lifetime predictions and to increase turbine system efficiencies. For this objective, phosphor thermometry shows great potential for non-invasive high temperature measurements on luminescent coatings. In this work, a phosphor thermometry instrument has been developed to collect two emission peaks simultaneously of an erbium and europium co-doped yttria-stabilized zirconia TBC, enabling an extended temperature range and high precision of the in situ temperature assessment. The luminescence lifetime decays and the intensity variations of both dopants were captured by the instrument, testing its high sensitivity and extended temperature range capabilities for accurate measurements, up to operating temperatures for turbine engines. The results open the way for the applicability of portable phosphor thermometry instrumentation to perform effective temperature monitoring on turbine engine materials and support the advancement of innovative sensing coatings. (paper)