Development of HEA Bond Coat Compositions for Thermal Barrier Coating Systems

The drive toward higher efficiency engines is demanding higher performance Thermal Barrier Coatings (TBC), both bond and top coats. This proposal is aimed at developing new and improved bond coats for the TBC system. STATEMENT OF HOW THIS PROBLEM IS BEING ADDRESSED High-entropy alloys (HEAs) have potential to be used as high temperature materials and in coating material applications due to their combination of strength, ductility, thermal stability, corrosion and wear resistance. We propose to develop new and improved bond coats using selected HEAs. Both cathodic arc evaporation and plasma spray will be used for coating deposition. WHAT IS TO BE DONE IN PHASE I In Phase I, we will initially explore cathodic arc evaporation of a few compositions selected from the design approach introduced by a co-investigator of this proposal. This will be a cost-effective process to quickly evaluate a few compositions. One composition will be down-selected from this initial screening for plasma spray deposition in Phase I. In Phase II, plasma spray technologies will be utilized extensively to deposit selected HEA coatings for field applications. COMMERCIAL APPLICATIONS AND OTHER BENEFITS Thermal barrier coatings (TBCs) applied to the surfaces of metallic parts in the hottest part of gas-turbine engines enable modern engines to operate at significantly higher gas temperatures, and therefore, at higher efficiencies than their predecessors. Gas turbine engines are a $42 billion industry worldwide (2010) with 65% of the sales accounting for jet engines and the remainder land-based engines for electricity generation. The latter fueled by natural gas or liquid fuels produce ~25% of all electricity in the U.S. and ~20% worldwide (2010). An increase in the engine efficiency will also decrease air pollution, especially with carbon dioxide, per 1 kW of produced energy, which is critical for regulating global warming. KEY WORDS Thermal barrier coatings, Bond coats, Gas turbine engines, Cathodic arc deposition, Plasma spray, High entropy alloy SUMMARY FOR MEMBERS OF CONGRESS TBCs applied to the surfaces of metallic parts in the hottest part of gas turbine engines enable modern engines to operate at significantly higher gas temperatures, and therefore, at higher efficiencies than their predecessors. UES Services, Inc. (UES Services) will develop new bond coatings for TBCs that will protect the metallic surfaces from oxidation and corrosion and enable engines to run at higher temperatures.