Advanced MCrAlY Alloys with Doubled TBC lifetime Part I Principal of Alloy design and FCT results

Thermal barrier coatings (TBC) have been used in both aero engines and industrial gas turbines for a few decades, however, the most commonly used MCrAlY bond coats which control air plasma sprayed (APS) TBC lifetime are still deposited by the powders developed in 1980s. APS TBCs predominately fails within top coat near interface /or at interface with thermally grown oxides (TGO). TBC lifetime can be increased by either increasing top coat fracture strength (strain tolerance) or reducing the tensile stress in top coat or both. By focusing on the reduction of tensile stress in top coats, three new bond coat alloys have been designed and developed. More than doubled TBC lifetime have been achieved by using new alloys as bond coat.