Collaborating Faculty
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Thermo-Mechanical Properties
• Relationship between external environment and mechanical properties through defect equilibria modeling.
This project is concerned with the thermo-mechanical stability of the solid oxide fuel cells (SOFCs). A change in the partial pressure of oxygen is expected to produce point defects in the ceramic conductors, which in turn will modify the bonding between the atoms. This change in atomic bonding manifests as changes in elastic modulus and surface energy, which will affect the fracture toughness and hence the failure of the SOFCs. For example, our recent results on ceria indicate that the elastic modulus can be reduced as high as 30% by exposing to a hydrogen environment. This phenomenon is explained by the increase in the oxygen vacancy concentration, which weakens the overall bonding between the atoms in the flourite structure. We would like to extend our studies perovskites, which are used as cathode materials in SOFCs. This project will involve synthesis of ceramic materials, structural analysis including x-ray and transmission electron microscopy, and mechanical properties evaluations using advanced techniques such as nanoindentation and microsample testing.
Selected Relevant Publications:
“Screen-Printed Dense Yttria-Stabilized-Zirconia Electrolytes for Anode-Supported Solid Oxide Fuel Cells,” B. White, E. D. Wachsman, M. L. Grilli, E. Traversa, A. Sanson, E. Roncari, and F. Pittalis, International Journal of Applied Ceramic Technology, submitted.
“The Effect of Oxygen Vacancy Concentration on Elastic Modulus of Flourite-Structured Oxides,” Y. Wang, K. Duncan, E. D. Wachsman, and F. Ebrahimi, Solid State Ionics, submitted.
"Modeling Defect Generation, Ambipolar Transport and Association in n-Type Mixed Ionic-Electronic Conducting Oxides," K. L. Duncan and E. D. Wachsman, Journal of the Electrochemical Society, submitted.
"Effect of Potential-Dependent Boundary Conditions and Non-Linear Potentials on Defect Distribution and Transport in n-Type Oxide Mixed Ionic-Electronic Conductors," K. L. Duncan and E. D. Wachsman, Journal of the Electrochemical Society, submitted.
“The Role of Point Defects in the Physical Properties of Oxides,” K. Duncan, Y. Wang, S.R. Bishop, F. Ebrahimi, and E. D. Wachsman, Journal of the American Ceramic Society, accepted.
“Stable and High Conductivity Bilayered Electrolytes for Lower Temperature Solid Oxide Fuel Cells,” J.Y. Park and E.D. Wachsman, Ionics, 12-1, 15-20 (2006).
“Thermo-Chemical Expansion of SOFC Materials,” S.R. Bishop, K.L. Duncan, and E. D. Wachsman, Solid State Ionic Devices IV, ECS Transactions, E.D. Wachsman, F.H. Garzon, E. Traversa, R. Mukundan, and V. Birss, Ed., 1-7, 13-22 (2006).
“Effects of Oxygen Vacancy Concentration on Mechanical Properties of Cerium Oxide,” Y. Wang, K.L. Duncan, E. D. Wachsman, and F. Ebrahimi, Solid State Ionic Devices IV, ECS Transactions, E.D. Wachsman, F.H. Garzon, E. Traversa, R. Mukundan, and V. Birss, Ed., 1-7, 23-34 (2006).
“Screen-Printed Dense Yttria-Stabilized-Zirconia Electrolytes for Anode-Supported Solid Oxide Fuel Cells,” B. M. White, M. L. Grilli, E. Traversa, E. Roncari, F. Pittalis, E. D. Wachsman and A. Sanson, Solid State Ionic Devices IV, ECS Transactions, E.D. Wachsman, F.H. Garzon, E. Traversa, R. Mukundan, and V. Birss, Ed., 1-7, 83-94 (2006).
“Evaluation of Time Constants Governing the Cathodic Reactions in SOFCs,” J. R. Smith, M. Orazem, K. Duncan, A. Chen, and E. D. Wachsman, Solid State Ionic Devices IV, ECS Transactions, E.D. Wachsman, F.H. Garzon, E. Traversa, R. Mukundan, and V. Birss, Ed., 1-7, 243-254 (2006).
“Synthesis and Characterization of Y 2Ru 2O 7 and Y 2-xPr xRu 2O 7 for the Cathode Application in Intermediate Temperature Solid Oxide Fuel Cells,” C. Abate, K. Duncan, V. Esposito, E. Traversa, and E. D. Wachsman, Solid State Ionic Devices IV, ECS Transactions, E.D. Wachsman, F.H. Garzon, E. Traversa, R. Mukundan, and V. Birss, Ed., 1-7, 255-262 (2006).
“Effect of Harsh Anneals on the LSM/YSZ Interfacial Impedance Profile,” J. R. Smith and E. D. Wachsman, Electrochimica Acta, 51, 1585-91 (2006).
“Ceramic PLD Coatings on Ferritic Stainless Steel Interconnect in IT-SOFCs,” F. Mattu, E.D. Wachsman and E. Traversa, Solid Oxide Fuel Cells IX, Electrochem. Soc., S.C. Singhal and J. Mizusaki, Ed, 2005-07, (2005).
"Defect Structure and n-Type Electrical Properties of SrCe 0.95Eu 0.05O 3- d ," S. J. Song, E. D. Wachsman, S. E. Dorris, and U. Balachandran, Journal of the Electrochemical Society, 150, A1484 (2003).
“Modeling the Performance and Stability of Bilayer Electrolytes for Low-Temperature Solid Oxide Fuel Cells,” K.L. Duncan and E.D. Wachsman, Solid State Ionic Devices III, Electrochem. Soc., E.D. Wachsman, K.S. Lyons, M. Carolyn, F. Garzon, M. Liu, and J. Stetter, Ed., 2002-26, 308-318 (2003).
“Defect Structure and n-Type Electrical Properties of SrCe 0.95Eu 0.05O 3- d ,” S. Song, E.D. Wachsman, S.E. Dorris and U. Balachandran, Solid State Ionic Devices III, Electrochem. Soc., E.D. Wachsman, K.S. Lyons, M. Carolyn, F. Garzon, M. Liu, and J. Stetter, Ed., 2002-26, 456-470 (2003).
"Solid State Oxygen Kinetics in Er 2O 3 Stabilized Bi 2O 3," E. D. Wachsman, N. Jiang, D. M. Mason, and D. A. Stevenson, in Proceedings of the First International Symposium on Solid Oxide Fuel Cells, Electrochemical Society 89-11, 15-29 (1989).