Harrington, George F., Skinner, Stephen J., and Kilner, John A.
Journal of the American Ceramic Society. Mar2018, Vol. 101 Issue 3, p1310-1322. 13p.
CERAMICS, GADOLINIUM, STRAINS & stresses (Mechanics), ION scattering, THIN films, and SOLID solutions
Lattice strain is a relatively unexplored route to modify the degradation effects in functional oxides for high-temperature electrochemical devices. In this paper, we present results on the segregation of Gd to the surface of strained Gd0.1Ce0.9O2-δ films using low-energy ion scattering to assess the surface composition. The potential for strain-modified segregation is discussed as well as the challenges in studying and implementing it. [ABSTRACT FROM AUTHOR]
Knauth, Philippe, Harrington, George F., Bishop, Sean R., Saltsburg, Howard, Tuller, Harry L., and Gauckler, L.
Journal of the American Ceramic Society. Jul2016, Vol. 99 Issue 7, p2415-2421. 7p. 1 Black and White Photograph, 1 Diagram, 2 Charts, 12 Graphs.
CERIUM oxides, NANORODS, DILATOMETRY, ELECTRIC properties, THERMAL expansion, and PROTON conductivity
The electrical and dilatometric properties of CeO2 nanopowders were examined as function of particle shape and size, including nanorods and nanocubes. Nanorods show continuous irreversible shrinkage, linked to particle reordering and compaction. Thermal expansion of CeO2 nanocubes was analyzed and was found to be consistent with literature data for microcrystalline ceria with no apparent nanosize effects. The electrical properties of the loosely compacted nanopowders were generally found to be characterized by n-type electronic conduction, except for proton conductivity contributions associated with adsorbed moisture at temperatures below 400°C. The PO2 and temperature dependences of the conductivity were examined in terms of defect chemical models. The lower effective enthalpy of reduction for nanorods (1.5 eV) in comparison with nanocubes (1.8 eV), both being much smaller than the value found for "bulk" ceria (4.7 eV), can be related to the larger surface to volume ratio of the nanorods, where oxide ion removal is more facile and less energy costly. [ABSTRACT FROM AUTHOR]