28-04-2014, 03:05 PM
Effect of Thermal aging on the erosion resistance of air plasma sprayed zirconia thermal barrier coating,
ABSTRACT
increase the performance, efficiency and reliability of thermal barrier coatings, it is important to understand the influence of the microstructure on the erosion resistance. Therefore, the erosion behavior of air plasma-sprayed 7 wt% yttria stabilized zirconia (7YSZ) thermal barrier coatings (TBC) at elevated temperatures was investigated. The paper focuses on both the porosity of the coating as well as the thermal pre-treatment of the ceramic. To simulate operating conditions on the ceramic samples, high-temperature erosion experiments at I093°C were carried out on as-sprayed samples as well as on samples, thermally aged at different temperatures up to 1482% in air prior to erosion testing. A significant dependence of erosion rate on porosity and thermal pre-treatment was found. Finally, a technique was developed to predict the erosion rates of air-plasma sprayed 7YSZ TBCs independent of aging conditions or porosity levels. Erosion rates seemed to be highly correlated to the micro-hardness of the zirconia TBC, A power law model was empirically derived to estimate erosion rates of plasma-sprayed 7YSZ ceramic thermal barrier coatings.