Journal
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Volume 16, Issue 6, Pages 2568-2575Publisher
ROYAL SOC CHEMISTRY
DOI: 10.1039/c3cp53979b
Keywords
-
Funding
- DGAC (ISS2 project)
- University of Toulouse (ATUPS grant)
Ask authors/readers for more resources
O-18/O-16 exchange annealing and subsequent Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis is used to investigate oxygen transport in dense, nanocrystalline (average grain size d approximate to 300 nm) ceramics of nominally un-doped BaTiO3. Isotope penetration profiles are obtained as a function of temperature, 973 < T/K < 1173, at an oxygen activity aO(2) = 0.20 and as a function of oxygen activity, 0.002 < aO(2) < 0.20, at T = 1073 K. All isotope profiles show the same unusual shape: a flattened profile over the first similar to 10(2) nm, followed by a short, conventional diffusion profile. We demonstrate that the entire isotope profile can be described quantitatively by a numerical solution to the diffusion equation based on an increase in the local oxygen diffusion coefficient close to the surface. This position-dependent increase is attributed to additional oxygen vacancies that are generated by diffusion of chlorine impurities out of the ceramics. The presence of chlorine derives from the chemical route necessary to produce nanometric powders: it thus indicates a new manner in which nanocrystalline ceramics may differ from their microcrystalline counterparts.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available