Interaction of molten silicates with thermal barrier coatings under temperature gradients

This paper examines the effect of temperature gradients on the interaction between silicate deposits and thermal barrier coating (TBC) systems. A dedicated test facility, in which a CO2 laser is employed to impose a controllable thermal gradient through the coating and underlying substrate, is used to investigate the interaction between two silicate compositions with state-of-the-art 7YSZ EB-PVD TBCs. The experimental results are then used to guide the development of expressions that describe the nature of silicate infiltration in the TBCs, the evolution of coating elastic modulus, and the generation and release of stresses.