Abstract
Thermal barrier coatings (TBCs) experience thermal gradients, excessive temperature, and high heat flux from hot gases in turbines during service. These extended thermal effects induce sin-tering and significant microstructure changes, which alter the resulting thermal conductivity within the TBCs. In this study plasma-sprayed Yttria Stabilized Zirconia (YSZ) TBCs using dif-ferent starting powders and process parameters were subjected to thermal aging at several tem-peratures and time intervals, after which their thermal conductivity was measured at room tem-perature. The thermal conductivity results are analyzed by introducing the Larson-Miller pa-rameter describing the creep behavior of thermal conductivity increase with annealing tempera-ture and time. One set of selected coatings was also annealed under the same conditions and the thermal conductivity was measured at elevated temperatures. The temperature-dependent ther-mal conductivity data is analyzed and used to predict long-term thermal behavior for general YSZ coating design.
