1 research outputs found
Oxygen diffusion in nanostructured perovskites
Nonstoichiometric perovskite-related oxides (such as ferrites and cobaltites,
etc.) are characterized by fast oxygen transport at ambient temperatures, which
relates to the microstructural texturing of these materials, consisting wholly
of nanoscale microdomains.
We have developed an inhomogeneous diffusion model to describe the kinetics
of oxygen incorporation into nanostructured oxides. Nanodomain boundaries are
assumed to be the high diffusivity paths for oxygen transport whereas diffusion
into the domains proceeds much slower. Using Laplace transform methods, an
exact solution is found for a ramped stepwise potential, allowing fitting of
the experimental data to theoretical curves (in Laplace transforms).
A further model generalization is considered by introducing additional
parameters for the size distribution of domains and particles.
The model has been applied for qualitative evaluation of oxygen diffusion
parameters from the data on wet electrochemical oxidation of nano-structured
perovskite SrCo_0.5Fe_0.2Ta_0.3O_{3-y} samples.Comment: Submitted for ICCMR-7 conference (Italy). Latex (elsart.cls), 15
pages, 7 figure