Laser surface texturing to improve EB-PVD thermal barrier coating adhesion

The development of internal cooling network in HP blades coupled with the use of thermal barrier coating allows to increase the turbine entry temperature in order to improve the efficiency of aero-engines. The thermal barrier system which is composed of three different layers deposited on a nickel-based superalloy substrate, is submitted during service to complex thermo-mechanical paths. The resulting damage mechanisms may lead to a premature spallation of the coating and a substantial deterioration of the substrate. To ensure a mechanical anchoring between layers leading to the slowdown of the coating spallation, different patterns have been developed on the bond coat by laser texturing. After surface morphology optimization, damage mechanisms of the textured thermal barrier coating systems will be presented.