EB-PVD thermal barrier coatings for aeroengines and gas turbines

Ceramic thermal barrier coatings (TBCs) offer the potential to significantl y improve efficiencies of nero engines as well as stationary gas turbines f or power generation. Our internally cooled turbine parts temperature gradie nts of the order of 100 to 150 degreesC can be achieved. Today, state-of- t he-art TBCs, typically consisting of an yttria-stabilised zirconia top coat and a metallic bond coat deposited onto a superalloy substrate, are mainly used to extend lifetime. Further efficiency improvements require TBCs bein g an integral part of the component which, in turn, requires reliable and p redictable TBC performance. Presently, TBCs fabricated hy electron beam phy sical vapor deposition are favoured for high performance applications. The paper highlights critical research and development needs for advanced TBC s ystems, such as reduced thermal conductivity, increased temperature capabil ity, lifetime prediction modelling, process modelling, bond coat oxidation, and hot corrosion resistance as well as improved erosion behaviour.