Thermal barrier coatings for aircraft engines: history and directions

Thin thermal barrier coatings (TBCs) for protecting aircraft turbine section airfoils are examined. The discussion focuses on those advances that led first to TBC use for component life extension and more re-cently as an integral part of airfoil design. Development has been driven by laboratory rig and furnace testing, corroborated by engine testing and engine field experience. The technology has also been sup-ported by performance modeling to demonstrate benefits and life modeling for mission analysis. Factors that have led to the selection of current state-of-the-art plasma-sprayed and physical-vapor-deposited zirconia-yttria/MCrAlX TBCs are emphasized, as are observations fundamentally related to their behav-ior. Current directions in research into TBCs and recent progress at NASA are also noted.