Development of High Entropy Oxides and other Complex Oxides for Advanced Thermal Barrier Coatings

Due to the need for increased efficiency in turbine engines, novel surface solutions will be needed to meet the challenges of higher operating temperatures and component longevity. This will require alternatives to legacy thermal barrier coatings such as higher temperature phase stability, lower thermal conductivity, and mitigation against corrosion caused by siliceous dust. One materials solution to address these needs are high entropy oxides (HEOs). Due to their complexity HEOs offer properties which may be favorable for advanced TBCs as well as offer vast possibilities for materials and coating development.

The following work presents insights into how HEOs and other chemically complex oxides can be designed, manufactured, deposited, and tested for TBC applications. Compositions were selected utilizing Oerlikon’s Rapid Alloy Development tool that captures integrated computational materials engineering and big data informatics. Descriptors for preferred properties are assigned to filter and select compositions. These chemistries were then fabricated into thermal spray powders and deposited via atmospheric plasma spray and characterized. Thermal properties such as conductivity, CTE, and sintering resistance, were evaluated and performance tests such as FCT and CMAS were conducted for select compositions. Overall results and findings are discussed and compared with legacy TBC materials to demonstrate market potential.