Study of the amplitude-dependent mechanical behaviour of yttria-stabilised zirconia thermal barrier coatings

Widely used in turbines for propulsion and power generation, thermal barrier coatings (TBCs) increase the efficiency of turbine engines by allowing them to work at higher temperatures, due to their thermal insulating properties. Typically TBC systems consist of a metallic bondcoat (BC) and a ceramic topcoat (TC). Previous research has revealed that ceramic TCs possess an amplitude-dependent mechanical behaviour and that they can be used as damping treatments, due to their good damping properties. The microstructure and the properties of ceramic TCs vary significantly depending on the employed deposition technique. This work investigates the differences in the mechanical behaviour of yttria-stabilised zirconia (YSZ with 8 wt% yttria) TC deposited by atmospheric plasma spraying (APS) and electron beam-physical vapour deposition (EB-PVD), by means of tests run with the amplitude dependent damping (ADD) test rig and of scanning electron microscopy (SEM) analysis.