RESUMO
The purpose of this study is to evaluate the efficacy of yttria-stabilized zirconia (3Y-TZP) as an inert phase to prevent the decomposition of Bi2 V0.9 Cu0.1 O5.5 -δ (BICUVOX.1) electrolyte under reducing atmosphere. A post-mortem scanning electron microscopy (SEM) study was performed after chemical stability tests under hydrogen-rich atmosphere using a Sieverts-type apparatus. SEM results showed that BICUVOX.1 decomposition starts under a hydrogen pressure of 19.7 atm at 300°C, even in the case of the composite containing 3Y-TZP. The microstructure of BICUVOX.1 after decomposition was observed to be composed of microspheres ranging from 10 to 100 µm formed primarily of metallic bismuth. In the composite, in addition to microspheres, the microstructure contained bismuth fibers growth from the grain area of the BICUVOX.1 matrix. Despite significant surface morphological modifications, the grain-boundary-arranged 3Y-TZP particles in a BICUVOX.1-matrix composite did not result in enhanced chemical stability.
RESUMO
The BiMeVOx family of compounds appears to be more attractive for applications at low temperatures when ionic conductivity is the determining parameter. The objective of this study was to analysis the influence of voltage of the behavior of the Schottky barrier in both BiCuVOX and BiTiVOX. The samples were analyzed by atomic force microscopy and electric force microscopy (EFM). EFM experiments were conducted to map the electric field distribution on the surface. The formation of Schottky barriers was observed, and their height and width measured. BiCuVOX samples show a barrier width of 140 nm, and BiTiVOX shows a barrier width of 350 nm. The applied voltage has no effect on the barrier width but increases the peak height as observed in the cantilever frequency as measured with the EFM technique.
