Please consider attending the following: MATERIALS ENGINEERING SEMINAR "The Effect of Biofuel Impurities on the Hot Corrosion of Yttria Stabilized Zirconia Thermal Barrier Coatings" By Jorge H. Ramirez Velasco Purdue MSE Ph.D. Final Exam Advisor: Professor Rodney W. Trice ABSTRACT Aircraft propulsion and industrial power generation have highlighted the critical role of gas turbines in modern society. Currently, components for these applications must withstand temperatures of at least 1400°C when operating within the combustor and the high-pressure sections of a gas turbine engine. With superalloys operating at its maximum capacity, ceramic multilayered materials systems known as thermal barrier coatings (TBCs) provide thermal and environmental protection to the engine's components. However, the introduction of biofuels into gas turbines applications has come with new challenges. The contaminants found in military and commercial biofuels are known to include oxides of alkali and alkaline earth metals and silicon oxides. While calcium-magnesium-aluminum silicates (CMAS) are typically ingested as particulate in volcanic ash and desert sand theaters, the impurity list in biofuels includes the necessary elements to form CMAS without exposure to any specific environment. CMAS is particularly destructive for operating temperatures above its melting temperature (~1250°C), mainly reducing yttria-stabilized zirconia (YSZ) TBCs lifetimes. Thus, identification of the corrosive compounds produced by the interaction of biofuel contaminants/TBCs and a specific understanding of its adverse effect is mandatory to avoid the failure of gas turbines. In this work, solutions containing the impurities of interest are prepared and sprayed onto TBCs simulating the deposit of the impurities during combustion. Subsequently, the TBCs are subject to thermal gradient testing up to 1400°C, and their microstructures evaluated. Date: Wednesday, November 20, 2019 Time: 9:00 A.M. Place: ARMS 3115