Thermomechanical Behavior of Plasma Sprayed Thermal Barrier Coatings

Results of fractographic and thermomechanical experiments on plasma sprayed thermal barrier coatings (TBCs) are presented which elucidate some of the structure/property aspects related to elasticity and fracture. The fractography results focus on the lamellar microstructure of TBCs with inter- and intra-splat cracks as the most prominent defects. The stiffness of the TBCs is addressed with respect to porosity, residual stress, applied stress, anisotropy of the spraying splats and annealing effects. The fracture behaviour is analysed in terms of segmentation and delamination cracks. The influence of inter- and intra-splat cracks on both macroscopic properties, stiffness and crack resistance, is discussed.