Mechanical and Dielectric Relaxation in 8 Mol% YSZ

Thursday, 28 May 2015: 10:20
Continental Room A (Hilton Chicago)
P. Gao, M. Radovic (Texas A&M University), G. Brankovic, and Z. Brankovic (University of Belgrade)
8 mol% Yittria Stabilized Zirconia (8YSZ) with high ionic conductivity is currently essential material for highly-efficient and environmentally-friendly energy technologies, such as solid oxide fuel cells (SOFCs). Mechanical properties, as well as electrochemical properties, of 8YSZ are of great importance for reliability and durability of SOFCs which work under harsh environment including high temperature, mechanical stress, electrical field, oxidizing/reducing environment, etc. In this study, mechanical behavior of 8YSZ was studied by cycling compression testing and Dynamic Mechanical Analysis (DMA) in the 25 – 600°C temperature range. Both testing methods demonstrate significant frequency dependent mechanical losses in the 50 – 500°C temperature range that can be attributed to anelastic reorientation of oxygen vacancy – dopant clusters. In addition, electrical polarization and impedance spectroscopy were carried on in the same temperature range, and the results are compared to the results of mechanical spectroscopy. Underplaying mechanisms for electro-mechanical coupling in 8YSZ were discussed in more details in this paper.