Multilayered Thermal Barrier Coatings by CVD

Turbine engine component life is currently limited by creep, creep-rupture, oxidation/corrosion, and thermomechanical fatigue. The use of protective coatings, such as nickel-chromium-aluminum-yttrium (NiCrAlY) and more recently platinum aluminides and various thermal barrier coatings (TBCs), has enabled higher temperatures and longer component life to be achieved, but component life and temperature capability still limit obtainable engine operating efficiency. Reduction in component temperature through the development and use of improved operating temperatures to be used at constant component life. Additionally, lowering oxygen diffusion through the TBC will increase the life of the TBC itself, and reduce or eliminate oxidation and corrosion of the bondcoat and underlying component structure. Extension of TBC technology to increasingly complicated combustor, blade, and vane geometries and cooling passages requires improved applilcation methods. In this Phase I project, Ultramet proposes to demostrate the chemical vapor deposition (CVD) of multilayered, low-permeability and low-conductivity improved thermal barrier coatings and bondcoats, and to quantify the improvement in performance thus made possible through analytical modelilng and burner rig verification.