| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advanced Materials for Energy Conversion and Storage VI
|
| Presentation Title |
Alloying Iron Foams with Nickel to Mitigate Kirkendall Microporosity Formation during Redox Cycling at 800°C |
| Author(s) |
Stephen K. Wilke, Andrew B. Geltmacher, Patrick G. Callahan, David J. Rowenhorst, David C. Dunand |
| On-Site Speaker (Planned) |
Stephen K. Wilke |
| Abstract Scope |
The lifetime of iron-based energy conversion and storage materials is limited during high-temperature oxidation/reduction cycling (e.g., in chemical looping or solid-oxide iron-air batteries) due to pulverization and sintering. Material degradation is typically attributed to the large phase transformation volume changes, but recently we have also identified Kirkendall porosity formation as a major underlying mechanism. Freeze-cast, lamellar iron foams (~70 vol. % porous) provide a promising architecture to accommodate the redox volume changes while facilitating redox gas transport, but during cycling the foams still densify and form a gas-blocking surface layer. To address the remaining Kirkendall effect, we fabricate and test alloyed iron-nickel foams (0-25 mol. % Ni) as a strategy to alter the solid-state diffusion kinetics and decrease Kirkendall microporosity formation. Using metallography, SEM/EDS, and X-ray tomography, we describe the role of nickel in microporosity formation, foam densification, and redox-induced structural changes. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |