PVD coatings for protection of aero engine components under challenging environments

Abstract

Advanced aero engines operate under extreme conditions. This ultimately calls for materials with increased high temperature capability and lightweight components that are pushed to its limits. Usage of coatings offers the potential to prolong lifetime, to increase operating temperatures, and to protect turbine components. Several PVD coating techniques that are used to protect turbine parts will be presented. Thermal barrier coatings (TBCs) are applied to increase lifetime and efficiency of turbine blades and vanes in aero-engines and land-based gas turbines by reducing the average metal temperature and mitigating the detrimental effects of hot spots. The presentation highlights the behaviour of coatings that are produced by electron beam-physical vapor deposition (EB-PVD) especially under high loadings of dust, commonly described as CMAS deposits, that are ingested in aero-engines during the flight. The presentation provides results on several new TBCs, especially their improved behaviour under the influence of deposits. PVD methods are also capable to protect TiAl against oxidation. Magnetron Sputtering is a suitable method to manufacture the desired complex coatings that are either multi-element coatings such as TiAlCrY, TiSiAl, or complex MAX-phases. Finally, for very challenging conditions in terms of temperature that can be present in engines and hypersonic flight applications, CMC (Ceramic Matrix Composites) and Ultra High Temperature Ceramics (UHTCs) are potential solutions. Both ceramic materials need complex and demanding coatings to provide an adequate service life. The presentation will show results on promising PVD-based metallic and ceramic coatings for these materials.