Understanding Alloy Chemistry for Enhanced Environmental Resistance

Materials used in technologies with aggressive chemical environments such as gas turbines, fuel cells, batteries, and solar thermal power plants are being pushed to their operation limits to meet market demands for higher power and efficiency at reduced emissions and operating costs. The continued development of next-generation technologies requires a fundamental understanding of how materials respond to extreme chemical environments, which will enable the design of high performance alloys. This award supports fundamental research to learn how the composition and structure of high performance alloys can be engineered to improve performance in these environments. The ultimate goal is to provide tools for the design of corrosion-resistant materials for aggressive chemical environments found in future sustainable technologies, such as heat transfer fluid for concentrated solar power systems, gas turbines, and molten carbonate fuel cells. The knowledge gained in this project has broad applicability across fields essential for the future of U.S. competitiveness, including electrochemical energy storage (batteries), materials synthesis, and corrosion-resistant coatings. The research will be incorporated into courses at the graduate and undergraduate level, and will enhance K-12 outreach programs directed at broadening participation in STEM.

This research centers on understanding the impact of alloying elements in controlling (1) the degradation reactions at interfaces between the alloy and its chemical environment at elevated temperatures (650-950°C), (2) the structure and chemistry of the protective oxide layer, as well as (3) the thermodynamic and mass transport properties of alloys - critical factors in the formation of protective oxide layers. Based on a model Ni-Al system, the research team will determine the thermodynamic, mass transport properties, and interfacial degradation reactions of Ni-based alloys under the systematic control of alloy chemistry (Cr, Pt, and Hf) using electrochemical techniques. The researchers will test the hypothesis that alloying elements (Cr, Pt, and Hf) can enhance environmental resistance of the Ni-Al alloys by facilitating the formation of a protective oxide layer (Al2O3). The work will result in the creation of a database of thermodynamic, mass transport, and interfacial corrosion properties of multi-component alloys, as well as the experimental techniques for their measurement.