A detailed characterization of BaMgAl10O17 : Eu phosphor as a thermal history sensor for harsh environments

Knowledge of component temperatures in gas turbines is essential for the design of thermal management systems and to maintain the lifetime of highly loaded parts as the firing temperature increases in pursuit of improved thermal efficiency. When on-line methods such as pyrometers and thermocouples are not suitable, a thermal history sensor can be used to record the maximum temperatures and read them out after operation. Currently, temperature sensitive paints are applied to obtain temperature profiles in gas turbine components but they present some limitations. A new method based on irreversible changes in the optical properties of thermographic phosphors can potentially overcome some of these difficulties. In particular, a sensor based on the oxidation of europium based phosphors has shown great potential. In this work the temperature sensing capabilities of the phosphor BaMgAl10O17:Eu are investigated in the temperature range from 700 °C to 1200 °C, and suitable measurands defined. The influence of practical factors comprising excitation fluence, exposure time, dopant concentration, cooling down time and atmosphere composition, on measurement accuracy and sensitivity are also reported