Effect of thermal aging on the erosion resistance of air plasma sprayed zirconia thermal barrier coating

To 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-s prayed 7 wt% yttria stabilized zirconia (7YSZ) thermal barrier coatings (TB C) at elevated temperatures was investigated. The paper focuses on both the porosity of the coating as well as the thermal pre-treatment of the cerami c. To simulate operating conditions on the ceramic samples, high-temperatur e erosion experiments at 1093 degrees C were carried out on as-sprayed samp les as well as on samples, thermally aged at different temperatures up to 1 482 degrees C in air prior to erosion testing. A significant dependence of erosion rate on porosity and thermal pre-treatment was found. Finally, a te chnique was developed to predict the erosion rates of air-plasma-sprayed 7Y SZ TBCs independent of aging conditions or porosity levels. Erosion rates s eem to be highly correlated to the micro-hardness of the zirconia TBC. A po wer-law model was empirically derived to estimate erosion rates of plasma-s prayed 7YSZ ceramic thermal barrier coatings. (C) 1999 Elsevier Science S.A . All rights reserved.